Hi there, Sandy Allnock here with a pen review that is not a technical review.  All right, I bought way too many pens in my pen fetish that I've had lately.  That's what I'm telling myself, I did it for you to show you what the good pens are, not good pens. And I've got this fancy box, you do not need a fancy box. A lot of people put them in a drawer, in a little plastic thingy or something. I mean, like you don't need something fancy, but since I had all these, I thought it would be cool to get a fancy case. So I've arranged them in order of price. The two that I took out are like super cheap and the rest of these are really decent pens for drawing with. So let's start with the low end, the Platinum Preppy. And this one is kind of considered a throwaway pen, even though you can replace the ink in that little cartridge. I'll show you in a minute on a different pen, how you can replace it. These come in all different colors. They're great for things like planners or making shopping lists. And you can draw with them, but I don't find them to be particularly great to draw with. They feel a little bit like a big pen in their body because they're just lightweight cheap plastic, but for a fancy feeling pen to write your shopping list with, they're awesome. If you have little kids who wanna feel fancy, this is a great little pen that like 450, I think, up to maybe seven or eight dollars at the max is kind of the price range. So go check those out and see, cause they're fun. The Platinum Prefonte, I don't know if that's how you say it or not, but that one is basically an upgrade to the Platinum Preppy, a little bit nicer, but it's got the same cartridge thingy in it, the same little thing that holds the ink. And this one, you have to drop the ink in with a dropper into that little hole. Imagine me in my crazy, unsteady hands trying to do that. Yeah, that could be a mess. So there you go. It's one of the reasons why I don't like this one. I don't like things that are gonna make a mess on me. And then trying to shove it back in there and get it in just right so that it doesn't leak all over, that's a thing. So some people consider these two pens to be somewhat disposable. And they'll, I know a couple of friends who buy pens for other people just to get them busy drawing. You could put these in a stocking stuffer, that sort of thing, make them as a gift, attach them to a planner. I mean, they're just fun pens, but they're not great, like the pens that I would choose to use for artwork necessarily. But they write okay, they're not great. They don't have the pour that I like from a good pen, by which I mean, I like when the ink really just kind of pours out of the pen so I get a lot of ink on the paper. This Pilot Retropop is kind of fun. It's about a $20-ish pen. And the body is metal, so it feels more substantial. And the bladder on this one is weird, though. It's got this little thing that holds the ink and it's like a plastic or rubber squishy thing.  Of course, pop that bubble before you do it. But again, I get messy with pens like this and I don't like messy because it takes me forever to wash all that ink off my hands. So this is not one of my go-tos necessarily, just knowing that it's going to be a challenge for the likes of me to fill the pen. But I've done these little doodles, these little test doodles in this little sketchbook because I wanted to just try each of these pens all at once. I did all the filming in one day so I could remind myself, even though I bought some of these pens a month or two ago, what they all feel like in comparison to each other so I could get to a final recommendation. So this Muji, this one is really a kind of a cool pen. It's in the $20 to $25 range, depending on where you get it. And the body is much thinner than the pens that I like. So that's the only thing that I don't like about that one, but it writes beautifully. The nib is gorgeous on it.  I've added a piston converter to it and I'll talk more about piston converters as we go. It comes with a little cartridge that just pops in there and you can buy replacement cartridges to put in and not have to do any ink bottle stuff with them at all. And it writes nicely, it has good flow to it. It's the body size that you may or may not like. It's really dependent on the person. There's some people that are really particular about how the pen feels in their hand. The Nudler's Ahab Flex I bought because I wanted to try a flex nib and see what the heck that even was. And there are other nibs that I don't even have that eventually I want to try. And you can replace nibs on a lot of these pens but I'm not gonna go to that extent because it scares me, I feel like I'm gonna break something. But this one has a piston built into it and it's a plunger kind of thing.  So this one does not need a separate kind of ink cartridge or anything or a piston converter to put in it. The flexiness I was not impressed with just because I was expecting more, I think. It's a little flexy but not super flexy. There might be other flex nibs that have a wider variety.  But I found that I split the two points. There's like two tines on this thing and it would split and then I'd get a white line in there or it would get a little scratchy or whatever. You can also draw with these pens sometimes upside down. Just turn the nib the opposite way and right with it the other direction. There are some pens that do that, some pens you can't tell any difference and some pens just make a mess when you do that. But that flex nib you can write upside down. Pen BBS, this one, they number their pens instead of giving them names. This is a demonstrator pen. All the ones that you can see through are called demonstrator pens. And that means you can demonstrate. There's ink in there. And this one doesn't have much ink in it because I can't figure out how to work the plunger daily. It's got a real special system. I'm not even gonna go into it. I have not been able to function with it. I can get like maybe a quarter inch of ink into it. It's got this really nice big barrel and I can't get enough ink in there. The pen writes nicely, I just can't fill it enough. So I'm not recommending it because I don't know how to fill it. So there's that, right? Now, any of these fountain pens, by the way, if you're going to fill them with fountain pen ink and not with cartridges, you're gonna have to buy a bottle of ink as well. And I'll talk about ink in a little bit here. The Lamy Safari and All-Star pens. The All-Star is a little wider body than the Safari. And as far as I can tell, they're the same pen otherwise. One is just a little bigger in my bronze All-Star. I bought, it was like a, I don't know, anniversary, something, something type of pen. So it was a little fancier, a little more expensive. But I put a Piston Converter in them and these required their own Piston Converters. There's some that are universal ones, some that are special. And I have just got so many Piston Converters now that don't fit anything that I have because I didn't know which one to get. So there's that. Both of these have the similar problem for me. And I know there's tons of people that just they adore these pens, these Lamis. I'm not a big fan of them because I find that they get stuck. And by stuck, I mean when the pen has been sitting in the box for a day or two or three or four and you try to use it again, you have to sort of work with it and jiggle it to get it going. It just doesn't have that automatic flow. I don't have any other pens that do that. And this one also sometimes when you make a long, quick line, it'll skip. So I don't find the flow is good in these pens. They're in the mid-range and I was really surprised that they have this after all the great things I'd heard about the Lamis. When I bought the Allstar and it did that, I thought, well, maybe I'll get the Safari and see if it did and it did it too. So let's talk about my favorites. These next two are my favorites, the Twizby Eco. And again, this is a demonstrator and you can get them with different colored caps on them. And a demonstrator pen is clear so you can see all that ink, see all that delicious ink. It's really easy to fill that much. I wish that other pen would fill that much. But I like this pen enough that I bought two more. The reason I bought two more is because I have a medium and I wanted a fine and an extra fine so I could compare them for you. Yes, I live for you. I'm very nice that way. And it has a wrench that it comes with and tools and stuff because you can fill these by taking that back end off and doing an ink dropper into a nice big open area.  Or you can do what I'm gonna do, which is to use the little piston suction thingy to make it work. It comes with its own piston system. The nib itself is very pretty. Some of the nibs are not all that pretty and this is one that has a very pretty nib on it. And you can see that the ink would go from the body down into the nib as you use it. Now to fill them, you just put the piston thing down and this is the same for all the piston converters. You just close it up somehow.   And if it's a good piston then it generally does that really easily. The ink that I'm using here and that I'd recommend if you want a waterproof ink is platinum carbon. I have tons of ink too. I'll do a video someday on inks once I know more about them. But this bottle is like the coolest out of all the bottles. I mean, well, the bottle itself is not the coolest. I have some really beautiful bottles. But this feature is the coolest and I'm thinking I wanna find out how to get more of these for all my other bottles. It has this little insert. And at first I was like, what the heck is a chalice doing in there? A little plastic chalice. And I found a video online that explained it. So what you do with this is instead of getting all the ink stuck in the bottom, which when you get down to just the last little dregs of ink in a bottle, you can't quite get to it with your pen. But with this one, you turn it upside down and then the cup fills with ink. So you don't end up with ink that's useless down in the bottom. So I'm shoving the pen nib down into the ink and then just twisting the piston converter. So I'm just sucking the ink up into the piston. Actually, I was going down first and now I'm going back up and you can see I've got ink in there. I was demonstrating, so I didn't get all the way full. However, that's as easy as it is. And the only ink cleanup that there is is to wipe off the nib that went in there into the bottle itself. And I absolutely love the ones that are easy to fill that don't get ink all over my hands and the Twizby Eco does that. So I'm gonna do my little scribbles with the extra fine, the fine and the medium. If you are going for just one pen, I would definitely say Twizby Eco is a really good starter pen. Like, you know, if you're just looking for one that's gonna be a workhorse, it's gonna do a lot for you. It's got a lot of ink and holds a ton in there. It'll work for a long time. It doesn't seem to get gummed up. I haven't had it had any problems with skipping. It writes right away. And it's in like the $32 range for pens. And so if you're looking for something in that range, that is definitely my recommendation. And that's one of the reasons why I bought three of them because I not only wanted to compare them, but I wanted to make sure that this pen is all that the medium was because I've had this medium for a while and really enjoyed it. It's really fun. I mean, I even just make notes with it, not just drawing with it because I just love the way it writes. So there's that. The Twizby Eco comes with in the little box. It comes with a little diagram. So you can see how to fill it. If you can read Japanese bonus points for you, but the pictures are pretty clear and there's always videos for a lot of these pens and instructions in Japanese and a little paragraph in English. But those are my three recommendation pens. However, this is not my favorite pen. So if I were to just have one pen that could do me, this would be the Visconti Mirage. Now I told you the Twizby Eco is 32. This one is 149. You get fancy things like your initials on the back end of it. They'll give you a little metal chip things that are magnetic and put them on there. And it's really cool. The magnet inside this thing just snaps the cap on so nicely. The body of it is, I guess hexagonal. Not sure how many sides this actually is. Haven't actually counted them, but it's got a good feel to it. The nib is gorgeous and I like pretty things. So a pretty nib is a good thing. And of course I got the yellow one. That was the thing that got me to look at it because I was looking for a yellow pen because that's my favorite color. When posting the cap, which is putting the cap on the back, I always line up the clip on the top of the pen that's right across from where the nib is gonna be. And then that clip doesn't kind of rest on your hand. Makes it more comfortable for drawing. This one comes with a piston converter. So it better for that price for 150 bucks. But it writes beautifully. And if for any reason, any pen doesn't start working if you have to get them started, just take the piston and twist it a little bit and it'll push a little bit of ink into the nib and things will start to work. So now let's talk paper. I have two papers that I wanted to test against each other. This Paris paper for pens and Hanamool's lettering paper because I'd heard about both of them. The Paris paper for pens I'd heard most and I've been using that paper for a lot of drawings and it works fine. And all of a sudden I found this lettering paper. I thought that sounds interesting. So I picked up a tiny pack of it.  So I did the same boxes with each of my fountain pens on both papers. And this was part of my exercise of trying to decide once and for all if I'm gonna tell you what pen to buy. I wanted to be sure I had a good recommendation. I didn't wanna change my mind in a couple of weeks and go, well, you know, I really kind of like this one better. So I did all of this work in one day so I could have this flowing experience of all the pens and know exactly how they felt and what I liked and what I didn't about each one. So this little doodle exercise also taught me a lot about the papers themselves. The papers that you use with pen and ink, with fountain pen, you can of course draw on anything. But some of them are going to be a little more on the absorbent side, which means they're going to feather a little bit. They're gonna bleed just slightly. And some papers are not gonna do that as much. They're gonna be a little more on the smooth and not so absorbent side, but they need to not be so non-absorbent that they float. So there's a really fine line between the two and trying to figure out which papers are perfect. I haven't gotten to that point yet, but that's part of what this whole test was for. And I found that the Paris paper for pens, which you would think would be the perfect paper when it says paper for pens, ended up actually doing more of the fuzzing out than I expected. I didn't realize that it did that much, but I didn't realize it until I tried it against the Hannibal paper. Because it looked really great to me until I compared directly. And that was an interesting thing because it told me how little I actually looked super closely at my work. But if you need a paper that's gonna be super crisp, I would say the Hannibal is gonna be better. I also use a bunch of other different papers too. I'm always testing new fun things and trying every paper that I have with all the different mediums that I have. So, you know, who knows what papers I'm gonna find are great recommendations. I found some bamboo paper that I tried just the other day. And while I don't know enough about it to recommend it, it was really a lot of fun and it got really good line quality for me for the type of drawing that I did. It was a terrible drawing in how it ended up, but so we have the Paris paper for pens, which is a little creamier than the super white of the Hannibal. And the lines you'll be able to see just barely. I'm trying to zoom way in and it's not super clear, but you can see the crispness of the Hannibal lines on the right versus the Paris paper for pens on the left. But I was happy with Paris paper for pens until I got the Hannibal. So everything is in relation to everything else. So put all the pens back in the box. These two are gonna go back in the car and in the purse for shopping notes and that sort of thing. And this box comes also in a single tray instead of a double tray. So for people who are not gonna be a dork and buy 20 pens, then you can get one for just 10 pens or you can just put them in a cup or a drawer and that's just fine. So I did this other drawing on the Hannibal paper and using the Retropop pen. And I did this for Instagram and I actually drew this picture of a penguin. And his name is Wellington and he is the rock hopper penguin or one of the rock hoppers that lives in the Shed Aquarium in Chicago. And I have been watching him throughout quarantine season because since they were closed, they thought it would be fun to let the penguins have a little mental stimulation adventure and let them run around in the aquarium. So they got to meet the other critters and they got to go to the store and they got to go on stairs and they were just walking around all over the place. So if you go to the Shed Aquarium's Instagram or I'm sure they're doing it on their Facebook too but I tend to look more on Instagram, just look up the Shed Aquarium and see if you have little videos of these guys. I'm sure they're also on Twitter. So if you're a Twitter user, just go find them because Wellington's been having a really good time. He's been having a lot of adventures. And one of the things I was hoping, I don't know if this will happen by the time I post this little video on Instagram because at the time I'm doing this voice over I haven't posted it yet. But this little guy I'm gonna hope will be my ticket to get into the Shed Aquarium and like draw some behind the scenes of the penguins. I wanna go to Chicago after everything's over and visit the Shed Aquarium. I love going to aquariums in all different places in the country and drawing. I love drawing the fish and the animals and stuff. There's just something about that that gives me a little excited thrill.  I'm gonna give one little ode to ink, a very short ode when it comes to fountain pens. If you buy a fountain pen and you plan to just buy ink cartridges for it then you don't have to buy any ink bottles. You just buy more cartridges and you're fine. You're good to go. Just pop those in.  And I don't know enough about ink to tell you much except for this is the one black ink that I found that's waterproof. Is this carbon black by Platinum?  I found if you watched my Earth Day video recently that I had some ink in a pen and I thought it was the carbon black from Platinum and it was carbon black from somebody else and it ended up bleeding. So sometimes that just happens but you gotta work with what you got in your pen.  I have not gotten to that point because that terrifies me but I have also not gotten to the point of trying to store them empty because I'm using them a lot and if you're using them a lot then that's not usually much of a problem but if you're using a waterproof ink like this it's more likely if you let it sit for a month or two months it's gonna gunk it up. So just know that if you're not gonna use it very often you'll want to empty it and clean it in between uses but I recommend that you just get one and get started and you don't have to get a fancy pen like if you don't wanna get a fountain pen by all means get whatever makes you happy. I have classes on my website that I've taught with Sharpie pens just doodling with a Sharpie pen. You don't have to do anything fancy you can do that on computer paper it really doesn't have to be rocket science just do it. And I've got classes that you can take in learning how to draw in pencil and do shading and do perspective and stuff if that's what you wanna learn but just do it. I have a class that I launched a few months ago that has been kind of one of the best things I think I've done in a while which is 30 days to more confidence, sketching. And in that class I had so many people that started out on day one, day two, day three and they're like oh my gosh this is terrible I'm never gonna get it I'm awful and just blah blah blah and by day 15, 16, 17 they are all of a sudden saying man I can see the improvement I can see I'm getting better. And I'm not saying you have to go take that class but I am saying if you draw every day you will get better it's just going to happen. So don't worry about the first couple of days and if you do something that comes out like poop like my drawing on that bamboo paper don't worry about it like just it's a piece of paper so what you start on a new piece of paper start a new drawing just start. If you wait until you have the right paper or the right pen and the right everything you'll never get there. But for me having really beautiful pens that feel beautiful and paper that just feels like the pen is soaring across it that gets me excited. And then I'm more excited to sit down and draw. So if you're one of those the supplies are linked in the doobly doo down below and you can shop to your heart's content if that's what you need but just do it just do some drawing. Enjoy yourself enjoy the process and you will get better I promise. All right thanks so much for sticking around this long this was a huge crazy video. I will see you again very soon. Bye bye.


Hello everyone, I once again welcome you all to MSP lecture series on transfer metal chemistry. In my previous lecture I started discussing about the preparation of important and very useful coordination compounds and also organometallic compounds having labile ligand so that you can do substitution reaction to make desired complexes of your choice for whatever the desired application. So let me continue from where I had stopped. In my previous lecture I had wrote the preparation of rhodium chlorocort dimer and that is a very useful compound. So let me write few more complexes to make you familiar with the preparative methods. Let me give the preparation of another important compound of rhodium that is rhodium chlorocarbonyl dimer. This is the compound I am talking about. This is a dimer having symmetric chlorobidges. This is very interesting. This is a solid state reaction. Take rhodium trichloride trihydride and pass carbon monoxide at 90 to 95 degree centigrade. So you get this compound. So in this one what are the other products we are going to get, we are going to get. So let us try to see whether this reaction is balanced or not. In this reaction we are getting this phosphine, now one has to be very careful and this reaction has to be carried out in a well ventilated hood. So how to do this reaction? As I mentioned in this case we are not using any solvent. For this one it is very simple.  You have to bubble about couple of bubbles per second, very slow to minimize wastage of carbon monoxide. It is also very poisonous. Then what happens? It will keep on coming like this because of positive pressure and it touches here. It will start moving carbon monoxide and this entire place is immersed in up to here it should be immersed in liquid paraffin and heated to 90 degree to 95 degree centigrade. It should not exceed beyond 90 degrees in that case what happens? It may lose this water in that case it becomes anhydrous and that is not reactive. So you will not get the product and here of course this is an outlet for CO. So in this reaction when you are doing this the CO will react with rhodium chlorocarbonyl dimer in this formation and of course here the phosphine will be coming out and water will be coming out and then water vapors also will be condensed in somewhere here and then very nice crystals of this dimer will start subliming and it will come here. And you have some grayish color rhodium trichlorate trihydrate. You can visually monitor the disappearance of starting compound that indicates formation of rhodium chlorocarbonyl dimer and it is almost 100 percent pure and in case if you find some dust and other things due to the impurity present in rhodium chloride trihydrate what you can do is you take the product later of course is a fritt is there. You can add here trihexane and then you apply pressure so that you can collect it from this side solution and then solution on cooling to 0 degree temperature you can see very orange crystals of rhodium chlorocarbonyl dimer formation and it is moderately stable one can use it for further substitution reactions with various phosphines and other ligands. And in case carbon monoxide cylinders are not there that carbon monoxide can be generated in the laboratory by using formic acid and sulphuric acid. What you can do is you can take formic acid in a flask and then add using a dropping funnel sulphuric acid drop wise and when the carbon monoxide is liberated because of dehydration process water and sewer formed and this sewer will try to come out to the valve something like this so when you add from here sulphuric acid using a dropping funnel pressure equalizing dropping funnel you can see the better picture in any of this books. So here you pass here here you have sulphuric acid when a rhodium drop wise here to the formic acid and CO will come and this CO may carry moisture so it has to be pass it through again sulphuric acid and bubbling through sulphuric acid and collected here and then this can be used here.  Now let us go to another important compound of ruthenium, ruthenium dichlorosimene dimer. I shall write the structure later first I will give you the preparation take ruthenium trichloride take ruthenium trichloride trihydrate as usual and treat with two equivalents of a slightly excess of simene. Simene is this aromatic compound having this kind of para substituents and take this reaction mixture in ethanol and reflects it reflects we use this delta we get the desired dimer in almost quantitative yield. So this is how the dimer looks like and plus what we get is so this is a very useful compound in many catalytic reactions in homogeneous catalysis and of course this also once again when you perform some reactions with phosphins and other ligands this breaks symmetrically here and it generates a vacant coordination site. So there you can place a desired ligand and of course once you do this reaction in a polar solvent you can also knock out one of the chlorine and again put another phosphine or use a bidentate ligand and for removal of halogens from metal the best method is to use salts such as silver tetrafluoroborate or silver triflate or silver acetate okay silver triflate you can use or one can also use AGPF6 there are plenty of such salts are available having larger anion the advantage with larger anion is if the anions are larger the compounds readily crystallize and isolation in pure crystalline form and also looking into the structure would be very easy and one can also use corresponding potassium salts also if the compounds are more reactive otherwise ideal way is to use some of the silver salts and silver halide will precipitate out and that can be separated and you have anionic compounds cat anion complexes with this larger anions. Now let me give the preparation of another important compound Palladium allyl dimer so for the preparation of this one one has to make to begin with if you do not have potassium or sodium pallidate one has to make that one that is very simple take palladium chloride and treat that one with sodium chloride or potassium chloride in water you can get the corresponding pallidate once of making this one take this sodium tetrapallidate treat this one with allyl chloride so this is a method used for preparation of palladium chloride allyl dimer it has a haplocity eta 3 and another important compound is BD2 DBA thrice so of course I showed you other day preparation of palladium and platinum tetra crystalline phosphine very useful compound after that one another important compound that is widely used in catalysis as a starting 0 valent palladium complex is BD2 DBA thrice so let me give you the preparation of this one so what is DBA di benzene acetone so this can be prepared very easily starting from benzaldehyde and acetone one can prepare this compound in large quantities in almost quantitative yield few hours reaction this is simple condensation reaction once you have this one bright yellow color stuff one can treat this one with palladium chloride using a reducing agent such as sodium acetate this is called DBA this should be heated to strictly 55 degree centigrade one should not go beyond that one if you exceed this temperature it may leads to some other product or some reduction of palladium to palladium 0 and that becomes useless and also that reduces yield of the product initially BD DBA thrice is formed so this is a balanced chemical equation for the preparation of BD DBA thrice starting from P D P D palladium chloride this P D DBA thrice will be in equilibrium so what it does is in solution it forms this one plus DBA comes out so one gram of palladium chloride can give you as much as 3.5 grams of P D DBA thrice and of course once after making P D DBA thrice if you dissolve that one in chloroform and if you crystallize it comes as a solvated with chloroform something like this and if you crystallize this one in toluene it will be solvated with toluene or if you crystallize in dichloromethane one mole of dichloromethane will be X and if you want to use this compound which is free from any chlorinated solvents and if you think this chlorine will affect your reaction better to go for toluene solvated one otherwise for most of the purposes one can go for this one it gives excellent yield and also this compound very nicely crystallizes and handling would be very easy. How this is binding I will show you here it is a P D DBA thrice means you may be wondering what is the geometry something like this this double bonds will be binding and of course here you have phenyl groups are there ok. So, another one will also bind like this and you have about 3.2 separation is there palladium palladium. So, this is how it binds and palladium has diagonal planar geometry having weak palladium palladium interaction. Let me give you the preparation of some metal carbonyl complexes of course when I go to classification of ligands and discuss about carbon as a donor atom or ligands containing carbon as donor atom I shall give you more information nevertheless when we have homolyptic metal carbonyl there are 3 ways we can activate CO bonds for further substitution reaction one is thermal reaction. So, taking metal carbonyl and heating in presence of desired ligand using aliphatic or aromatic ligand solvents one has to be careful with aromatic solvents because aromatic solvent itself can bind in eta 6 fashion to form for example, if you if you take molybdenum hexa carbonyl and treat with benzene or reflects in benzene you may form some sort of eta 6 are in coordinated tricarbonyl complex like C6H6 MOCO3. So, in order to prevent the formation of aromatic complexes one should use solvents such as heptane or metacyclohexane and heating to about 100 degree centigrade can give you thermally activated where you can eliminate 1 or 2 carbon monoxide and in its place you can bring desired phosphines or some other ligands and then if you another method is photochemical reaction and photochemical reaction you do perform photochemical reaction using THF or something initially what happens carbon monoxide comes out and in its place loosely held THF coordination will be there and later when you add a better sigma donor ligand such as phosphine that can replace and of course when you the advantage with photochemical reaction you can monitor the reaction using IR and IR can tell you by just looking into how many observations we are getting stretching frequencies you can observe whether it is forming eta 5, eta 4 or eta 3 that also depends on the type of ligands you are using and sometime you also end up with getting a mixture of compounds and you should be able to know how to separate them. If not best is to go for CO4 complexes having two labile ligands so that you can do it very easily in a substitution reactions so those things also I will tell you and another one is you can also use mild reagents to replace carbon monoxide at room temperature and carbon monoxide comes out in the form of very inert gas and in its place you can now the site that is vacated by carbon monoxide can be substituted by phosphines and other ligands. So you can use three methods according to the convenience to begin with let me show you how to make some of these MOCO4 compounds having C2V symmetry for example if you take MO or in general MCO6 where M is chromium molybdenum or tungsten and treat this one with Narborna diene it is also called NBD take in heptane ok take this with MOCO6 or yeah MCO6 with slight excess of Narborna diene and heat it in heptane what you can get is a compound of this type having four carbonyl groups this is called bicyclo heptadiene this also called Narborna diene and here the advantage with this one is you can see this is a very strained chelating ligand and because of this strain what happens you can readily substitute this one with a bidentate ligand for example you take this one treat with DPPM perhaps you know what is DPPM already we discussed several times it can readily form this type of compounds in almost quantitative yield NBD comes out here and sometime if there is a problem of separating NBD what you can do the same reaction in reflex in hexane in that case what happens at that temperature when NBD comes out it undergoes some sort of polymerization to form insoluble stuff and that will stick to the walls inside and as a result this compound is dissolved in hexane and that comes out very easily and separation would be very easy. So there is a advantage sometime performing this reaction with slightly higher temperature so NBD gets polymerized sometime it also forms cyclic polymers one can use these compounds for further reactions of course in case of chromium molybdenum tungsten temperature little varies and also yields are little different one can get good yield in case of molybdenum and yields are much lower in case of chromium and tungsten and in place of NBD one can also use cycloctadiene also this also one can use this compound is slightly more stable compared to NBD complexes and again they have very characteristic smell once when they are replaced with appropriate ligands you can also the smell the liberated one near the reaction that also indicates that yes your reaction is complete or substitution is going on or it is completed you should be able to see. So another couple of important compounds of molybdenum tungsten are having four carbon monoxide groups are these complex piperazine complexes and this can also be made starting from MOCO6 here only in case of molybdenum and tungsten one can make this compound this piperidines will be binding here and this one you take this two and reflects in heptane within about two hours bright yellow precipitate is formed one has to do heart filtration heart filtration will ensure that unreacted MOCO6 or WCO6 comes out and after heart filtration whatever remains on the filter paper insoluble material that is this compound. Of course in heptane it is insoluble whether this compound is highly soluble in dichloromethane and at room temperature if you add any other phosphines two equivalents of mono phosphines or a bisphosphine you can readily knock off and make MOCO MCO4 complexes in almost quantitative yield. Why I am telling all these compounds are you can further use this compounds to make molybdenum tungsten two complexes that are very widely used in metathesis, olefin metathesis and ring opening polymerization reactions and other things in organic chemistry. From that point of view these are very important reactions. Let me continue giving the preparation of several other interesting compounds as we go through the classification of ligands that means I would stop at this juncture and in my next lecture let me talk about the classification of ligands and there are several ways to do classification. Let me do the classification by choosing donor atoms so that way I can cover almost all ligands we come across under one donor atom for example hydrogen donor atom, nitrogen donor atom or oxygen donor atom or carbon donor atoms all important ligands coming under those donor atoms would be discussed in detail. So until then have an excellent time reading chemistry.


Item Number- SCP-3841 Object Class- SAFE Special Containment Procedures- Cover stories attributing the debris ring around light and B to asteroid impacts and other non-anomalous stellar phenomena have been disseminated. Discovery of SCP-3841 by civilian astronomers is impossible due to the planet's atmospheric haze. However, in the event this does occur, any resultant research will be discredited by Foundation-run academic journals, which will publish their own papers presenting different explanations for the discoveries. Amnesticization of involved persons may be performed if deemed necessary. Four monitoring satellites and surface observation probes have been deployed by Foundation extrasolar exploration vessels to monitor light and B for signs of further activity. Light and B is classified as off-limits for potential human interstellar colonization in the near future. Description- SCP-3841 designates the remnants of a halted K-class event, K-3841, that occurred on the exoplanet Light and B at an unknown time in the recent past. The exact details of the event are unclear, though it is known to have resulted in the extinction of all life on Light and B, including its native sapient civilization hereafter Lightenians. The primary cause of K-3841 is presumed to have been SCP-3841 Omega. An organism whose skeletal remains span two continents on Light and B. The cadaver is 3,300 kilometers long and is hexapedal in nature, similar in structure to the bodies of Lightenians, with the frontmost two legs possessing feet that could act as graspers. When alive it likely had a skull with the same structure of Lightenians skulls, having two lower jaws and an upper jaw. But the entire head region has been destroyed. Fragments of it have been found in craters across the planet, in orbits around Light and B, and in orbits around Light and Star at the escape velocity of Light and B. Surrounding the lower portion of the skeleton is a crater with a 300 kilometer radius, likely the site where SCP-3841 Omega began its formation. The hind legs and tail structure of the skeleton are incomplete, suggesting that the organism had not fully formed when it expired. What anomalous means the organism used to stay alive in spite of its size are unclear. What substance forms the skeleton is unknown. No tools such as drills and laser carvers have penetrated its surface, and no amount of applied heat or force have caused damage. Decaying organic matter is attached to the sides of the skeleton, holding some sections together, which progressively converts into a reddish-brown slurry of organic chemicals that falls from SCP-3841 Omega. This currently covers much of the region surrounding SCP-3841 Omega, filling former lakes and oceans. The last of the matter attached to the skeleton is expected to finish decaying in 50 years. Other structures of anomalous origin have been discovered in the vicinity of SCP-3841 Omega. Exploration teams investigating Lightenian cities found several structures of concentric circles formed from thousands of Lightenian cadavers, all of which had been attached by fusion of the limbs. Skyscrapers, primarily those ringing the crater, have calcified organic growths formed from fused Lightenian bodies that extend in directions away from the crater's epicenter. These reach lengths of up to 0.6 kilometers and heights of up to 1 kilometer, many having collapsed in recent years. Symbols of potentially thomic nature are also carved into mountain ranges, islands, and remaining skyscrapers. Lighten B is barren as a result of K-3841. No living fauna, flora, and a microscopic life have been found, and all regions previously containing liquid are entirely dry. CO2 and methane are the most abundant atmospheric gases, forming a dense haze that encompasses the planet and blocks light from Lighten's star. Atmospheric conditions and radiation levels are consistent with those of global nuclear fallout. A gradually dissipating debris ring of rocky matter orbits Lighten B. Its origins are uncertain. Little knowledge exists on Lightenian civilization. Present observations indicate that they had reached the same level of technological advancement as modern humanity, though what culture they had has not been determined. Book-like objects and the remnants of computer systems have been uncovered, but have all contained cognitohazardous depictions of SCP-3841 Omega that induce vegetative states in organisms that view them. All Lightenian cadavers discovered to date lack a brain-equivalent organ, despite the presence of empty spaces in their skulls where a brain could reside. Most cadavers were found with their heads pointing in the direction of SCP-3841 Omega's crater. While the exact events of K-3841 are not understood, hypotheses have been proposed to explain the death of SCP-3841 Omega. Initially it was believed that mass nuclear bombardment of the head caused its destruction, which while potentially an explanation for the nuclear fallout, was ruled out after tests with nuclear equipment failed to damage recovered skeleton fragments. No other known weaponry possessed by the Lightenians could have caused the damage. The leading hypothesis is that, during the formation of SCP-3841 Omega, it gained such a mass that it generated a gravitational field sufficient enough to alter the orbit of a small moon of Lighten B. Continued alterations from the field and further size growth led to the moon's orbit intersecting with SCP-3841 Omega, resulting in it directly impacting the head. The accidental death then halted K-3841. This is consistent with the existence of the debris field and the widespread of skull fragments. Lighten B is not expected to be habitable for the next thousand years, if ever. Addendum 1. SCP-3841 Omega Decay Slurry Alterations From 2030 to 2033, probes that had been continually analyzing the chemicals in the SCP-3841 Omega Decade Matter Slurry detected increasing quantities of chemicals similar in nature to amino acids. RNA and DNA equivalent structures emerged soon after. In 2034, the first single-celled organisms were observed, and as of 2035, colonies of multicellular organisms have formed in the slurry and the land bordering it. The colonies primarily convert CO2 to O2. Additional probes and monitoring devices are scheduled for deployment on Lighten B. Previously predicted time spans for habitability are under reconsideration.


A senior administration official tells CNN that President Biden told Prime Minister Netanyahu that the U.S. will not participate in any offensive operations against Iran. Do you think that's the right call or should direct U.S. military action as some of your colleagues in the Senate are suggesting? Should that be on the table? I don't agree with that. And I just think we should follow and have Israel's back in the situation. I don't agree with the President. That doesn't change anything that he's a fantastic President and I'm proud to stand with him and campaign for him and vote for him. Marco Rubio was just on the show and he said the White House leaking the fact that Biden told Netanyahu not to directly respond, to take the win, quote unquote, was offensive to him because it seemed to suggest that it's Biden trying to appease the far left in his party. What's your response? Well, I don't know. I mean, the President is entitled to his own views and whatever he decides to do. But I would never capitulate to the fringe. I'll never pander to that as well. In fact, that helps that empowers Hamas. You just heard Senator John Federman accuse Biden of empowering Hamas by capitulating to the fringe in his party because he dared to say that he doesn't want tensions between Israel and Iran to escalate. He's trying to cool tensions. Now I have my criticism of Biden in this situation and we'll get to that in a moment. But not that long ago, Federman is the one who said that anyone who criticized Biden is a Trump supporter. And we also have to start having, you know, all kinds of Democrats criticizing the President too publicly. I don't understand why. I don't know what's in it for you to do that, whether you're just chasing clout or you want to make in the news or anything like that. But if you're not willing to just support the President now and say these kinds of things, you might as well just get your MAGA hat because you now are helping Trump with this. Well, I guess it's time for Genocide John to break out his MAGA hat because he is now publicly criticizing the President and in effect helping Trump by his own logic. Now I say this because Axios tweets that Biden was hit with a barrage of criticism from both sides of the aisle by telling Netanyahu that he won't support an Israeli counter-attack against Iran. Now that's a bit of a misrepresentation because if you dive into the article, Biden isn't actually being criticized by both sides. The only Democrat on the record criticizing Biden is John Federman. In fact, Chris Coons is mentioned in the article, but he agrees with the President's approach. In other words, John Federman is the only Democrat teaming up with Republicans to lambast Biden for not directly wanting to escalate tensions further, which puts him in the same camp as neocons like Marco Rubio and even John Bolton who are currently chomping at the bit for war with Iran. Last night, the Iranians launched 320 plus crews and ballistic missiles and drones. It's a blessing that the Israelis find only 1% got through, but not every night is going to be that good. And unless Iran sees a powerful response, that risk will continue. And the way to reestablish deterrence is not proportional. That's academic talk. The way you established deterrence is by telling your adversary, if you ever try that again, the price you will pay will be so much higher than any gain you think you can get, you shouldn't even think about it. I don't know what they'll do, I can't predict it, but I will tell you this. If Joe Biden, as some press reports have it, is urging the Israelis not to retaliate at all, he is an embarrassment to the United States. This is an American interest to make sure that Iran, which is the principal threat to international peace and security in the region, is at a minimum put in its place. So he's beating the war drums hard, but expectedly so. Now, it's also really deeply irresponsible for so-called journalists like Jake Tapper to bring on one of the most war horny people in America when things could spiral out of control. Like we don't need his input right here, not only because Bush-era neocon should be in prison and not on television, but because his appearance is redundant. Why bring on neocons like John Bolton when you can have John Federman pair it the same exact shit?  But I mean, Bolton, he had the same exact thoughts about Biden capitulating to the fringe as John Federman had. And I would say this too about this escalation, this fear of a wider war. The administration fears a wider war because it's worried about gasoline prices in the United States. It's worried about the left wing of the Democratic Party. The fact is, Israel has been in a wider war since October the 7th, which the administration has resolutely refused to recognize. Now, you expect that from a neocon like John Bolton. He doesn't care at all about escalation. And to the extent that he cares, he wants things to escalate further because he wants war with Iran and has been open about wanting war with Iran for decades. But when it comes to Democrats like John Federman, we shouldn't just accept that they're being openly militaristic on national television, right? But like John Bolton, he also doesn't care about escalation. Senator, what is your reaction to Iran's attack on Israel and how worried are you that this is the beginning of an open war between the two countries? Well, a couple of things, actually. I think it really demonstrates how it's astonishing that we are not standing firmly with Israel and there should never be any kinds of conditions on all that. When a nation can launch hundreds of drones towards Israel, I'm not going to be talking about conditions ever. And second, I think that also was Iran had to have some fireworks after Israel smoked that Iranian general. And I am here for that. And I think it's just a matter of theater, part of it as well too. And finally, it demonstrates how unstable things are and why we need to lean in and stand with Israel. He is almost indistinguishable from John Bolton at this point, although there are two exceptions. First, if you watch Bolton's full interview on CNN, which you should not, but if you do, he comes up with a range of targets in Iran for Israel, whereas Federman basically says, look, I'm not going to make any recommendations. Israel leads and will follow. So there's one difference. Second, and what makes Federman the weaker war propagandist than Bolton is he acknowledges why Iran launched those missiles at Israel in the first place, because Israel smoked in Iranian general, which he totally thinks is cool and supports by the way. Now that right there is a rookie mistake, because if you're trying to manufacture consent for a war, you end up undermining your case. If you don't portray the enemy as a belligerent bad guy who just spontaneously chose to attack you or your ally for no reason, because if the audience finds out that Israel actually struck Iran first, then they might learn that Israel is actually the real aggressor in this situation and not Iran. And they might not necessarily view further attacks by Israel as defensive. And you always want the audience to think that this is defensive. Any move that you take is defensive. Any move that your opponent takes is offensive by definition. That's like war propaganda 101. So Federman overplayed his cards here and accidentally revealed why all of this is happening. On April 1st, Israel bombed an Iranian embassy in Damascus and the hundreds of drones fired at Israel by response was actually the real retaliatory response. But after they go to Iran into an attack, they are now vowing to quote retaliate against Iran. Now Iran is vowing to respond again if Israel responds again. And now Israel is ironically demanding that the UN Security Council take action against Iran for the attack that they provoked out of them. And I find this so interesting because when the UN Security Council passed the ceasefire resolution, well, Israel chose to ignore it and accuse them of supporting Hamas. But now that the UN Security Council might be of use to Israel, well, they're choosing to respect the authority of the UN Security Council. Interesting how that works, right? So Israel is basically the geopolitical equivalent of a bully that cries to the teacher after they get punched back. Now here's the thing, both Iran and the United States, they don't actually want war. But Israel and specifically Netanyahu is trying to drag them both into conflict. But the question is why and nobody knows for sure we can't get into Netanyahu's head. We can only speculate. But I think that Professor Sultan Barakat, he has some really compelling theories that I want you to hear. But I think the reason he's doing it is achieving colorful objectives.  Iran will retaliate as a threat. He's also managed to silence the criticism, the little criticism that started to come from Washington D.C. concerning his operations in Gaza. Now it's very unlikely that we hear anyone saying anything against Israel over the coming few days. The fact that the U.S. President is rushing back to D.C. That's an example. And Israel is deploying war planes in the air. It suggests that they think it is imminent. They think it's imminent and they probably think, they're made to think it's imminent by Israel. And they think that Israel needs them even more. He's also going to accelerate the delivery of the weapons that Biden has promised, including the critical F-35 jet fighters. And the most, I think, critical is he's going to silence the opposition within his own country. Now he will stop the right for demonstrations on the basis that we're all on the threat of Iran. I think the professor is right. There is increasing pressure on Netanyahu to not invade Rafa and to withdraw entirely from Gaza. But all of a sudden, nobody's talking about that. Nobody's talking about what he's doing in Gaza. We're all focused on Israel versus Iran. That's the point. Netanyahu has an interest to keep the genocide in Gaza going as long as possible and to escalate as much as he can because his own political survivability hinges on it. And this isn't necessarily something that's unique to Israel or Netanyahu. He's not the first leader to use war for purposes of political expediency. And he won't be the last. But war with Iran only serves Netanyahu. It doesn't serve the people of Israel. It doesn't serve Iran or the people of Iran. And it certainly doesn't serve the United States and the people of the United States. In fact, war with Iran would be catastrophic for Joe Biden's reelection campaign, which is why he's telling Netanyahu that the U.S. isn't going to support retaliatory strikes against Iran any further. But here's the problem. As Trita Parsi puts it, Biden needs to prevent further escalation, not just declare his desire to stay out of it. And that right there is a really important point because it's not enough for Biden to continue urging Netanyahu to do things when Netanyahu just doesn't listen to anything Biden has to say. He disregards his input. It's in one ear out the other. And that's because Biden hasn't used his leverage or even tried to hold Netanyahu accountable in any way. Biden needs to take concrete steps to stop further escalation. Otherwise, he could inadvertently pull the United States into a war with Iran, whether he likes it or not. Because the U.S. is going to defend Israel regardless if they started it or not. Netanyahu knows this, which is why he's playing this deadly game of chicken right now. The U.S. already intercepted some of the drones that Iran fired. And they'd do it again if they had to, obviously. So Biden needs to make sure that the United States isn't put in that position. And that requires him to do what he's been needing to do for a long time.  Cut off the weapons. Cut off support. And support for this position, contrary to popular belief, isn't actually fringe. Both of the genocide Johns, both Bolton and Federman, want you to believe that it's fringe, but it's not. On April 12th, major Democratic Party organizations signed a joint letter calling on Biden to do just that, including Indivisible, Move On, the SCI Union, Working Families Party, and even the Center for American Progress, who has literally hosted events with Netanyahu. And I say all of that to say that pressure on Biden to cut off weapons to Israel is at an all-time high. And Netanyahu knows this.  But odds are, Biden is going to be more apprehensive about cutting off weapons to Israel now, more than ever, so as to not upset the warmongers who will accuse him of capitulating to the left or Hamas or Iran or whoever if he chooses to act right now. But if he does actually want to avoid war with Iran, cutting off Israel is a necessity.  We can't lose focus of that. Netanyahu wants us to not think about that. He wants us to be distracted, but don't get distracted. Now, the reason why politicians like John Federman are increasingly frustrated with the so-called fringe of the Democratic Party is because he's tired of them questioning him about his support for genocide everywhere he goes, case in point. Senator, you do agree that the vast majority of hostages who have been released were released through ceasefire negotiations, true or false? No, that's a question. You don't want to answer it? Senator, I always thought you were an anti-racist, but it seems like you value Israeli lives more than you value Palestinian lives. Is that true? So you think an Israeli life is more valuable than a Palestinian life? He's not even pretending anymore. He used to say, oh, I care about both Palestinians and Israelis.  But I mean, none of us should be surprised considering the fact that this is the same exact guy who pulled a gun on a black jogger when he was the mayor of Braddock. So, you know, it's not necessarily a shocker that his racism extended towards other people as well, including Palestinians. But John Federman is one of many politicians cheering on Israel's genocide in Gaza and now chomping at the bid for war with Iran at the behest of Israel, specifically at the behest of Netanyahu. He is a symptom of a sickness and deep rot within our political system. And if he thinks that I'm fringe, that's fine by me. If being against war and genocide makes me fringe, I will happily wear that fringe title like a badge of honor. I'd rather be fringe and moral than mainstream and immoral with hands that are blood-soaked.


Down in front back it goes far side.  It was easy


Good day everybody. This is going to be a demonstration of the entire ease of Vegas and the company Vegas This is a supine cadaver. I'm standing on the right side camera person is also on the right side So the extent of the ease of figures is from the neck to the abdomen The cervical ease of Vegas is approximately from this level where my instrument is pointing to T1 So that is a cervical ease of Vegas Then if I were to lift up this then we have the thoracic ease of Vegas Thoracic ease of Vegas is from T1 to T10 To T1 is the thoracic inlet T10 is the ease of agile hiatus in the diaphragm It is running in the posterior medial sternum and then we have the abdominal ease of Vegas Which is a very short segment but we have pulled it down to make it look a little big It is from T10 to T11 Initially the ease of Vegas is situated a little on the right side and we can see it is located to the Right of the descending thoracic aorta But as it goes down at the level of diaphragm It moves a little in front of the aorta and it moves to the left and we can see the aorta is moving to the back So it moves to the left and this is where it exists through the ease of vigil hiatus So therefore abdominal segment of ease of Vegas is from T10 to T11 This is only just half an inch apart from that there are a few other points The cervical portion of the ease of Vegas and thoracic part of ease of Vegas does not have any serosal covering So therefore there is no protection While the abdominal part of the ease of Vegas is encircled by visceral baritoneum, which is referred to as the serosa Now we come to the sites of ease of vigil constrictions The first constriction is at its origin itself And that is referred to as the upper ease of vigil sphincter or the pharyngeal ease of vigil junction This constriction is produced by a muscle called the cricopharyngeus muscle Which is the muscle of the pharynx and that constitutes the upper ease of vigil sphincter This constriction is approximately 15 centimeter from the incisor teeth as seen through an ease of vigil scope The next constriction is at this complex that we can see here We can see this is the arch of the aorta The arch of the aorta as it goes it curves posteriorly and behind and therefore it compresses the ease of vigil from the side And we can see it here. It compresses the ease of vigil on the side here So this is another constriction and closely accompanying that constriction is this constriction produced by the bifurcation of the trachea into the left and the right principal problems So these two constrictions together are considered to be approximately at the level of 25 centimeters from the incisor teeth Aortic arch constriction is from the sides therefore it is best seen in an anterior posterior view While the tracheal bifurcation constriction is moved from anterior posterior So therefore this best seen in a lateral view of a barium swallow This is a barium swallow to show the aortic arch and the left main bronchus constriction of the ease of vigil And the third constriction is at the ease of vigil hiatus Which is at the level of 40 centimeters from the incisor teeth and this constriction is produced by This structure of the diaphragm Now if you were to look closely we can see this muscle fibers that we see here This is the right crust of the diaphragm The right crust of the diaphragm as it goes it completely encircles the ease of vigours and it comes back again This constitutes the lower ease of vigil sphincter and this constitutes the lowest constriction for the diaphragmatic constriction This is another barium swallow to show the diaphragmatic constriction and the dilatation of that called the phrenic ampulla So we have seen the two sphincters as we have seen the constrictions Now let's take a look at the blood supply and the venous drainage The blood supply of the cervical to the ease of vigours is the inferior thyroid artery This is the thyroid and the inferior thyroid artery is a branch of the Subclavian artery Venus drainage is to the inferior thyroid vein which drains into the brachialcephalic vein the thoracic part of the ease of vigours the blood supply is from the descending thoracic aorta the ease of vagal branches and the venous drainage is to this vein here This is the gaseous vein So this is also part of the systemic circulation because it drains into the supia vena gava Abdominal part of the ease of vigours gets a blood supply totally different This is the celiac trunk and we can see these branches this is the left gastric artery and The ease of vigil branch of the left gastric artery supplies the abdominal part of the ease of vigours and the venous drainage is to the left Gastric vein which drains into the portal vein So therefore we have a very important clinical correlation here The abdominal part of the ease of vigours belongs to the portal circulation The rest of these are figures belongs to the systemic circulation So in the sub-bucosa of the ease of vigours at the lower end. There are small microscopic communications Which is not visible in a normal person and those communications are referred to as the porta systemic communications In a patient with alcoholic cirrhosis and portal hypertension These porta systemic communications become dilated and then they become known as ease of vigil varices Which we can see through an endoscope and these can rupture and they can lead to life-threatening hematomases This is a distinction specimen from another cadaver to show alcoholic maternal cirrhosis of the liver and This is an ease of vigours scopic view the lower end the ease of vigours to show ease of vigil varices Which I described just now The next point which I want to mention to you was about the nerve supply of the ease of vigours We have seen this nerve here and we can see this nerve here This is the right vagus and we can see the right vagus is coming down from the neck and it is Going in front of the sub-cavian artery and is entering into the thorax It is going behind the helm of the lung Similarly the left vagus this is the left vagus and we can see it is coming in the carotid sheath It goes behind the helm of the left lung and below the helm it breaks up into a plexus And we have removed most of the plexus, but we can see some of the fibres of the plexus here And after that the left vagus comes anterior and we can see that here It is curving anteriorly and The right vagus goes posterior and we can see it is going posterior and Both of them exit the thorax through the same hiatus. That's the isophageal hiatus The left vagus or the anterior vagus is the smaller one It supplies only the anterior part of the stomach and it supplies the hepatic and the bilia plexus The right vagus, the posterior vagus is the larger one and it supplies up to the neck cap Surveical isophagus and the thoracic isophagus The cervical isophagus drains into the lower deep cervical nodes and the thoracic isophagus It drains into the stereometastinal nodes While the abdominal isophagus it drains into the celiac nodes Cancer of the thoracic isophagus and the cervical isophagus they tend to spread very rapidly because there is no serosal covering And therefore cancer of the isophagus is very difficult to treat and the life expectancy and the prognosis is very poor The best way to study the isophagus is by means of a barium swallow followed by isophagoscopy Another gold standard test for the isophagus is isophageal Pressure recording which is referred to as isophageal manometry, which is required in mortality disorders which I will describe just now and Because there is no serosal covering in the thoracic part of the isophagus while doing an isophagoscopy rupture of the isophagus and various unit is is a likely possibility And finally some other pathologies pertaining to the isophagus Sometimes there may be a mismatch in the peristaltic constrictions of the isophagus and that can lead to dysphagia One such condition is referred to as press by isophagus and the other is what is known as diffuse isophageal spasm They are all because of abnormalities of the Sympathetic parasympathetic supply of the isophagus So these are some of the points which I wanted to mention to you about the isophagus and the vagus nerve In the cervical region thoracic region and the abdominal region. That's all for now. Dr. Sanja Sanyal signing out David was the camera person my MD1 students are my silent spectators. If you have any questions or comments Please mention the comment section below. Have a nice day


Welcome back to our lecture series, Math 3120, Transition to Advanced Mathematics for Students at Southern Utah University. As usual, I'll be your professor today, Dr. Andrew Missildine. This is the first video for lecture 25, for which let me remind you in the previous lecture 24, we introduced so-called properties of relations. We indicated five properties that a relation can have. Recall that a relation is a subset of the Cartesian product. It's a way of connecting two objects that belong to a set together. There were a couple of properties we introduced. We had talked about the reflexive property and its antonym, the irreflexive property. We talked about the symmetric property with its counterpart anti-symmetric property. And then we also talked about the transitive property. Now there was a reason why we picked these four properties. These are the four, five properties, excuse me. We talked about these five properties the most often because these are properties we often want relations to have. And it usually don't just want one or two.  Now some of them are for the most part mutually exclusive except for trivial cases. So we're not gonna get all five of them. But there are some examples of very important relations that exhibit many of those properties we had talked about. Now the one that gets the most attention in a course like Math 3120 is the notion of an equivalence relation for which we will talk about that in the very next lecture, number 26. But in this one, before we talk about equivalence relation, I actually wanna talk about its often forgotten stepbrother, the notion of a partial order. This sometimes gets neglected in a Math 3120 topic, lecture series for example. We're not gonna do it in our lecture series but like notice in the textbook that this lecture series is based upon the book of proof. There actually is no topic about partial order. So this is gonna be completely supplementary for this video. So if you have been following along with the book, do make sure to take amply good notes for this topic because again, this is completely coming out of, this is not in the book of proof I should say there. All right, so what is a partial order? So imagine we have a set X. First of all, a partial order is a relation on X. So that is our partial order we often are gonna draw a symbol that in some regard looks like the less than or equal to symbol. So many people will just use less than or equal to. You'll notice mine actually has a little bit more like curly Q to it. And that's to make it look like a less than or equal to symbol, but not actually the same thing. Now, if anyone's actually trying to create such a symbol in latex, I do wanna mention that the less than or equal to symbol you probably know is backslash le. But this symbol right here, its name is actually backslash P-R-E-Q, sorry, P-R-C-E-Q. The P-R-C would give you this without the line on the bottom. The E-Q puts the line on the bottom. The P-R-E-C is short for predecessor. So it's trying to suggest there's some type of relationship between an element and the next element. So that's what that symbol is in case you want to replicate it. But some other partial orders we're gonna see in a moment like the set containment symbol. I mean, it's even on the screen right here. It also very much resembles this, but as opposed to this one, which comes to a complete point, this is more rounded, this is a compromise, there is some curvature, you know, concavity is there, but it comes to a cusp nonetheless. Anyways, we're gonna try to use this symbol for a little bit as a generic partial order. And this is because it's by analog a generalization to the less than or equal to symbol. We've talked about that in just a second. So a relation is called a partial order if it satisfies the following three properties that a relation can sometimes satisfy. To be a partial order, you must have the reflexive property which remember the reflexive property says that each element X inside of the set is related to itself. And this holds for every element in the set. Every element is related to itself, it's reflexive. You look into the mirror, you see reflection, that's the reflexive property. Now for a partial order, it's also required that the anti-symmetric property holds for which reminder, what is the anti-symmetric property? The anti-symmetric property says that if X is related to Y and Y is related to X, then that can only happen when X and Y are equal to themselves, right? X and Y have to equal each other. Now we do allow for that because of the reflexive property, right? If X equals Y, then X of course is related to Y because X is related to X. Now the anti-symmetry says that the only time that the relation goes in both direction is when equality happens. So you can never reverse the relation without it being equal already. And then the third property that a partial order has is the transitive property, which as a reminder of the transitive property says that if X is related to Y and Y is related to Z, then that means that X is related to Z. And so any relation that satisfies these three conditions, reflexive, anti-symmetric and transitive, we call that a partial order. The naming of this will make a little bit more sense in just a moment. Now the set X for which the partial order is a relationship on, the set X equipped with a partial order makes the set into what we call a partially ordered set. Or some people refer to this as a post set for short, partially ordered set, post set. And so a partially ordered set is a set with a partial order. Sometimes we say a partial ordering on it. And the name, I mean, we'll get a little bit more into this in a moment. Why this called a partial order is because this relation is giving an ordering on it. It gives us some way of saying that an element is bigger than another element. And so the canonical example of a partial order is take the set of real numbers. If you take two elements inside the set of real numbers, A and B, and these could be positive, negative, zero, they could be rational, irrational, any real numbers here. We say that A is less than or equal to B if B minus A is a non-negative number. So that's what it means for A to be less than or equal to B, that when you take the difference, B minus A, you don't get something negative, you get something positive, or it could be zero. Like if A is equal to B, then B minus A will equal zero, that's okay, we do want this thing to be reflexive after all. If you take any number A, A minus A is equal to zero, which that is not negative, and therefore we get that A is less than or equal to A. It satisfies the reflexive property. What about anti-symmetry? Well, if you have anti-symmetry, if A is less than or equal to B, that means B minus A is not negative, okay? And likewise, if you have the other direction, B is less than or equal to A, that means A minus B is of course not negative, like so. And so what that then gives us here, which you'll notice that B minus A is just negative one times A minus B, and you can factor the negative out on the other side, B minus A, like so, for which then if you times both sides by negative one, you'll get that B minus A is less than or equal to zero, that is B minus A is not positive in this situation. Now you might wonder, like, is the definition of less than or equal to circular because I'm using this symbol to describe itself. This right here is just a shorthand for non-negative, and this right here is a shorthand for non-positive. I can describe a positive number without any reference to the linear ordering of the real line or anything like that. So don't worry, this is just shorthand. I'm not having a circular definition here. But my point is, to check anti-symmetry, if A is less than or equal to B, that gives you the B minus A is greater than or equal to zero. If B is less than or equal to A, that implies that B minus A is less than or equal to zero here, the only way these are both happening is because B minus A is equal to zero, which means that B equals A. So the anti-symmetry property holds as well. And then for the last one, for transitivity, for transitivity we would take A is less than or equal to B, we then also take A, sorry, B is less than or equal to C, and we wanna argue that A is less than C. So how do we do that? We'll notice that this right here tells us that B minus A is not negative. This one right here tells us that C minus B is not negative. When you add those together, if I take B, if I take C minus B and I add it to B minus A, well, that clearly simplifies to be C minus A. But if you take a non-negative number plus a non-negative number, that is still non-negative, and this then tells us that A is less than or equal to C. So we get that. So in fact, this is a transitive relation and therefore this is a partial order. And this is essentially where the name comes from. It's a partial order because we have an ordering. With the real numbers, this less than or equal to symbol tells us that you have one number less than or equal to the other number. That's where the ordering is coming from. Now, in the case of the real numbers, and you could also talk about the rational numbers, the integers or the natural numbers as well, as subsets of this poset, they themselves also become partially ordered sets using the exact same relation. Any subset of a poset is itself a poset with that same ordering. Now this right here with the real numbers is an example of what we call a total order or a linear order for which every element, there's a relationship between A or B. So if you take any two elements A, there is a relation between them. One is either less than or equal to the other or vice versa. Now in general, that's not a requirement. We'll see an example of that in just a second. But in general, that's not a requirement to be a partial order. There does not have to be a relation between elements of the same set. So given two elements X and Y, it doesn't have to be the case that X is less than or equal to Y or that Y is less than or equal to X. If that does happen, if there is a relationship between X and Y, we say the elements are comparable. This would happen if X is less than or equal to Y or Y is less than or equal to X. So let me give you an example of this. And this actually explains why we call this a partial order as opposed to a total order that happens on the real numbers. Because in general, only some of the elements are comparable and as such, we have them partially ordered. We need another axiom. If we want to guarantee a total ordering, these three properties here don't guarantee it by themselves. All right, so a canonical example of a partial order that is incomplete and hence why it's justified to call it partial is to look at the power set of any set. So X is any set whatsoever. It could be a finite set. It could be an infinite set. It could be an empty set for all I care. You take any set whatsoever, then P of X remember is the power set of X by definition, this was the set of all subsets of X. Then if you take the power set of X and you equip the relation of set containment, that is the subset symbol, this then forms a partial ordering on the power set and thus the power set can be thought of as a partially ordered set, okay? Now to prove that a relation is a partial order, you have to check the three axioms, the three properties that it needs to have. And typically people go in the order that I've already listed, reflexive, anti-symmetric, and transitive, but you can go in any order, it doesn't matter. People generally start with the reflexive property, it's the easiest one, it's the first one listed. Admittedly when it comes to a partial order, the anti-symmetric property is generally the hardest one to do, but it typically comes second. Transitive in my opinion is usually the medium one, but we usually put a third there. So let's check that. Why is the subset symbol, the subset relation reflexive? Well, if we want to show that a set is a subset of another, we take an arbitrary element of the left set and argue that it is inside of the right set. So if X is inside of A, then X is inside of A. That's a fairly straightforward statement, I think we all would agree that's a true statement. Now since X was an arbitrary set of A, this then shows that A is a subset of A. We already talked about this before, but here's a formal proof in case there was any doubt. A is a subset of A. This symbol is a reflexive relation, okay? Now let's go to anti-symmetry here. Now while this can be difficult in general for the subset symbol, this is actually fairly straightforward. If A is less than or equal to B, and B is less than or equal to A, so we assume the relation goes in both directions. This is then like the definition of what it means for two sets to be equal. If A is a subset of B, that means every element of A is an element of B. Now if B is a subset of A, that means every element of B is an element of A, and two sets are by definition equal to each other when they have the exact same elements. So every element of A is an element of B, every element of B is an element of A, so A and B have the exact same elements, that makes them equal. That's the definition of equality on sets. And in fact, this is how one usually proves that two sets are equal to each other. You show that they're subsets in both directions. So honestly, how we prove that sets is equal is essentially using the anti-symmetric property of this symbol here, right? So it is anti-symmetric. This one's fairly straightforward. It's really built into the definition of equality of sets. So that one wasn't so convoluted or anything like that. The third one, transitivity. We would, to show transitivity, we would assume two relations. A is related to B, and B is related to C. That would manifest itself in this situation as saying that A is a subset of B, and B is a subset of C. What we then need to show is that A is related to C. That is the first element here is related to the third element there, which means we need to show that A is a subset of C. Now, how do I show that A is a subset of C? I'm gonna take an arbitrary element of A and argue why it belongs to C. So take the element X right there. X, take X to be a generic element of A. Now, by assumption, since A is a subset of B, every element of X is an element of B. Therefore, X is an element of B. But by our other assumption, B is a subset of C. Every element of B is also an element of C. So since X is an element of B, that means that X is an element of C. And since X was a generic element of A, this shows that every element of A is an element of B, and that's what it means to be a subset. So we've now shown that the subset relation is reflexive, anti-symmetric, and transitive. That makes it into a partial order, and therefore the power set of any set is a poset, which is kind of fun, right? The power set is a poset, right? It's like an abbreviated power set. You might say poset, and someone might think it's the other poset, the partially ordered set, and you would be right still. That's kind of a fun little coincidence there. This is really, this example right here is sort of the canonical example of a partial order that's incomplete. Let's try to offer a concrete example. Let's take the set X, which contains three elements, A, B, and C, and let's introduce some other sets here. So we'll take Y to be the subset that only contains A. We'll take Z to be the subset that contains A and B. I need another one, but I ran out of letters, so I'll go back up the alphabet. We'll take W to be the set that contains B and C, like so. So these are all subsets of X, and thus members of the power set. Now, some relations are gonna be very straightforward here. So like Y is a subset of X, Y is a subset of Z, W is a subset of X, for example. These are relations that do hold inside of this power set, but it turns out there are some relations that don't hold. For example, Y is not a subset of W. Y contains the element A, W does not, and therefore Y is not a subset of W, but it also goes the other direction. Y, or excuse me, W is not a subset of Y. W contains the element B, Y does not. I mean, W also contains the element C and Y does not, but it turns out only one counter example is necessary here. Y is not a subset of W, but W is not a subset of Y. They are not comparable to each other. These are example of incomparable elements. Similarly, we have that Z is not a subset of W because Z contains A and W doesn't, but W is not a subset of Z because W contains C and Z does not. These give us two examples of incomparable elements that do exist inside of this partially ordered set, and this phenomenon here is exactly why we call it a partially ordered set. The relation does describe order. It does tell us when one element is larger than other, but because of incomparable elements, it's only partially ordered. Some elements we can't say are bigger or smaller than each other. Let's consider one more example of a very important partial order that we've discussed before, the divisibility relation. Of course, we never talked about it being a partial order before because we never had that vocabulary, but now let's actually argue that under the right conditions, divisibility forms a partial order. And so using divisibility, we can construct a poset. So take, for example, any positive integer N, then let X be the set of positive divisors of N. So for example, if we take N to equal 12, then we would take X to equal one, two, three, four, not five, six actually, N12. So these are the six positive divisors of 12. So consider this set right here, the divisors of 12, or the divisors of some positive integer N in that situation. If you equip the divisors of N with the divisibility relation, because it is a relation, this actually makes it into a partially ordered sets. Now, how do you show that something is a poset? You have to show that the relation is a partial order, which always means three things, reflexive, anti-symmetric, and transitive.  I'm sure there's some mnemonic device you could do there. R, anti-symmetric, T, so rat, I guess. I don't know, think about a rat eating a relation. I don't know, use whatever mnemonic device you want. We got to check those three things, and we'll do that in that order. The proof of a partial order always has those three ingredients. Let's first check that that divisibility is a reflexive relation. Now to do that, we have to take an arbitrary element of X. Our set X is the set of positive divisors of N. So being an element of X is an equivalent thing to saying that D divides N. So just so you're aware, when I say that D divides N, now I'm just saying that it's a member of X, okay? So what I didn't need to do to show that it's reflexive, I need to show that D divides D. But to show that D divides D, I need D to equal something times D, and that has a natural candidate's one. So notice that D equals one times D, and that shows that D divides D. So we get that divisibility is a reflexive relation. Okay? I had mentioned earlier that anti-symmetry is generally the hardest one, and this will then manifest that prophecy I made. At least we'll give an example of such a thing. It turns out the divisibility anti-symmetry can be a little bit problematic. And this is actually the reason why we require things to be positive, because it turns out the proof of anti-symmetry would fail if we allowed for negative numbers here, but since we've only restricted our attention to positive integers, I think we'll be an anti-symmetric relation in that situation. All right, so to do that, we need to take two elements of our set. So take elements D and E, they both are positive divisors of N, that means we belong to the set X, and then let's suppose that D divides E and E divides D. So to prove anti-symmetry, since it's a conditional statement, there's an if and then a then. We assume the if part and then we prove the then part. We're gonna assume that D divides E and E divides D, and then we need to argue that D and E are equal to each other.  This is just basic direct proof right now. So because D divides E, that means there exists some integer A such that D times A is equal to E. So these ones are connected like so. Now, because E divides D, there exists some positive integer B such that EB is equal to D, like so. So you have the yellow relation that gives us that equation and the blue relation gives you the second equation like so. So, okay, let's then go forward with that. Notice that both of these equations involve the integers E and D. So if I substitute one into the other, like let's take this equation and then substitute the equation for E. If we carry that forward here, D is equal to EB, but D is itself equal, sorry, E echo is equal to DA times B, for which if you rewrite that, D is equal to D times AB. Now, there's a common factor of D here in this situation. And because this is an equation with integers, I can divide by D, but wait a second. If I wanna divide by D, I do need to make sure that D is not equal to zero. But remember, we're choosing positive divisors of N, D is not zero because zero is not positive. So you can divide both sides by D and you're gonna end up with one equals A times B. All right? Like we mentioned earlier, because D and E were positive integers, A and B themselves had to be positive integers to make those divisibility factorizations work. And as such, the only way you can have a product of positive integers equal to one is that A and B themselves have to equal one. But then come back to this equation right here, D equals EB. Well, D equals EB, but B is equal to one. So that means D equals one E, which then makes it equal to E. So because we had the relation going in both directions, it enforced that D and E were equal to each other. And this shows us that divisibility is anti-symmetric. And like I said earlier, it is requisite that we have positive integers. Because notice that negative two divides two and we have that two divides negative two, but two is not equal to negative two. If you allow divisibility to range over all integers, it's not anti-symmetric, but over the positive integers, you do get anti-symmetry in that situation. So that's an important, a little caveat I want to make mention there. Anti-symmetry was the hardest one. Transitivity is not so bad here. So let's take three arbitrary elements of X. So DEF, they're all elements of X, which means they divide N, they're divisors of N. And then we, again, transitive is and if then statement conditional. There's hypotheses, D divides E and E divides F. Then we have a conclusion, D divides F. So we will assume the hypothesis, we assume D divides E and E divides F. Then we conclude that D divides F, but we have to provide the justification in the meanwhile here, okay? Now since D divides E, that means there's a positive integer A such that E equals A times D. Likewise, because E divides F, that means there exists some positive integer B such that F is equal to E times B. So I'm just unraveling the definitions of divisibility here. For which case then, how do you end with D divides F there? If you want to D divides F, you're going to have to find some integer when times by D gives you F. And so by combining these equations together, we don't get kept in planet, we actually are gonna get the equation that we're looking for. Because notice that both of these equations involve an E. If you substitute this into the other, you get the following, F equals EB. Now E is equal to AD. So notice we have F is equal to D times AB. Since AB is a positive integer, we get that D divides F and that gives us the conclusion. So therefore, divisibility is a transitive relation. And so now we've shown all three properties, reflexive, anti-symmetric, transitive. We've got the whole ugly rat looking at us right now. And this is the general template for proving something's a poset. You check the relation as reflexive, anti-symmetric, and transitive. Now, one more thing I wanna enter into this video about partially ordered sets is how do we visualize partially ordered sets? Cause we've talked about before how a relation can be visualized as a digraph, a directional graph here. It turns out because of the properties of a partial order, we can actually simplify the relational digraph significantly. And this gives us what's referred to as a haze diagram. The haze diagram for a poset X with relation less than or equal to there. What you do here is whenever, well, the vertices of your graph are gonna be elements of X, okay?  Whenever there's a relation between X and Y, but there's no one who sits in between them. So if Y is the immediate successor of X, we then draw a line and no others. Now, unlike the relational digraphs we drew earlier, we don't draw arrowheads on these things. Let me give you an example of such a thing. So take this set X equals ABC and consider the power set, which because of the set containment symbol, the relation there, this makes it a poset. We talked about this in depth earlier. Notice that this set contains, this poset contains eight elements. The power set because X has cardinality of three, the power set will have a cardinality of two cubed, which is equal to eight. So there are eight vertices on this graph, which you see illustrated on the right right there. I'm gonna organize it in an upward direction. I'm gonna put the smallest element on the bottom. I'm gonna put the biggest element on the top and this thing always flows upward. This is why on a hazard diagram, we never draw arrowheads because the direction is always flowing upward.  I don't need arrows because I know that's how haze diagrams are drawn. Now the very smallest element in this poset is the empty set. The empty set is a subset of everything. Now, when we draw a line on the haze diagram, we only draw the line for immediate successors. So for example, the empty set is a subset of the singleton A and there are no other sets in between them because since this only contains one element and this contains zero elements, the only way you'd have to fit in between is you'd have to have less than one but greater than zero elements, which is not possible. So the singleton is an immediate successor of the empty set and in fact, all three singletons are. So we're gonna draw arrows like this. Then with regard to the singleton A, let's just consider it for a moment. It is a subset of A, B, A, C and A, B, C. It's also of course a subset of itself. Now in a haze diagram, we don't draw loops like with a relational diagram, we would draw a loop like this because the singleton A is related to itself. We don't draw loops on a haze diagram because since it's a partially ordered set, we know it's reflexive. I don't need to tell you with an illustration that's reflexive, I know that as part of the definition. So with a haze diagram, we draw no loops because those loops offer a bunch of, they just come, they make it more complicated and add so much encumbrance to the diagram that we don't need them because we know, oh, it's a subset. I know that it's reflexive, okay? Also, we don't draw arrowheads because for partially ordered sets, the relation is anti-symmetric. I know that the direction goes upward, it never goes downward. There's no two directions, it's always flowing up. So I don't need the arrowhead because I know the direction it goes, okay? That's again, simplification we get to the diagram there. Now again, the subset A is a subset of A, B, A, C and A, B, C. But the immediate successors of A are A, B and A, C. I'm not gonna draw a direct arrow to A, B, C. Instead, because the relation is transitive, right? Because the relation is transitive, I don't need a direct arrow to A, B, C. I just need a path. Remember with a relational digraph, if there was a path from one vertex to another, there must have been a direct edge if the relation was transitive. POSETs are fact transitive. And so because there's a path from A to B, from A to A, B, C always traveling upwards, I don't need a direct edge because the path, because there's a path, I know there's an edge. And so haze diagrams are designed exactly to take all of the pertinent information of a partially ordered set, but have it abbreviated and simplified. I don't need arrowheads because it's anti-symmetric. I don't need loops because it's reflexive. I don't need all of the possible edges because it's transitive, any path I also can infer is an edge.  Let's look at some examples using divisor graphs. These are often referred to as divisor graphs. So for example, if we look at the positive divisors of four, we're gonna get one, two and four. And by divisibility, one divides two, one divides four, but it's not the immediate divisor. Two divides four and there's nothing in between them. So this one, this divisibility graph is an example of a linear order, a total order, because the graph forms a line. One divides two, two divides four. And then the other relation is one divides four, but I get that because there's a path here. This is an example of a linear or sometimes called total order. The haze diagram will look like a line in that situation, which is why we call it a linear order. Total order because everything is comparable to each other. Now in general, divisibility graphs, haze diagrams, are not going to be a total order. Like for example, if you take the divisors of six, the divisors of six are gonna be one, two, three and six. And the haze diagram would look like the following. One divides two, one divides three. Two divides six and two divides three. All the other relations can be inferred from what's there. One divides six because there's a path there. There's nothing between one and two or one and three with respect to divisibility. There's nothing between two and six or six and three with respect to divisibility. This would give us that haze diagram there. Let's do one that's a little bit more complicated. Let's do the divisor graph for 24. The divisors of 24 are one, two, three, four, six, eight, 12 and 24 itself. Of course, every divisor graph will include the number and itself, it also include one. And as you're building the divisor graph, like a little hint I can give you is one always goes on the bottom and always goes on the top, okay? Then the next ones that are gonna be immediately above one are gonna be its prime divisors. The prime divisors of 24 are two and three. These are gonna be the things that are immediately above one because after all, the only divisors of a prime number are one and itself. So there's no other divisors that sit between them, all right? So then the numbers that sit above the prime numbers are gonna be those which have two prime divisors, like six, which is two times three and four, which is two times two. A repeated prime is perfectly acceptable there, all right? Then the next numbers are gonna be those with three prime divisors, like eight, which is two times two times two and 12, which is two times two times three.  Those with four prime divisors, five prime divisors, six prime divisors until we reach the top. And so this gives us then the haza diagram for the divisors of 24.


From Soldiers Radio and Television, this is the Army Now. The Army celebration continues with a twilight tattoo at Joint Base, Meyer Henderson Hall, Virginia. The Army's most senior enlisted soldier attended the event and shared his thoughts.  I'm very excited. You know, we've got amazing men and women that serve every single day and those that serve before. It's an amazing opportunity. He also added the soldier's dedication to their country has remained tried and true from the very beginning. You do something that less than one percent of the rest of the American people can do. Serve our nation. We're proud of our service. We believe that we're part of something larger in ourselves and that we're protecting the American way of life. I think the same hole is true today as it did 237 years ago. That's the Army Now.