It's great to be after lunch and I think let's approach this in the spirit of this document and we write this from the perspective of kids But as a bunch of adults, let's play right and that's what the system needs to start doing is to start playing together a little bit better Let's also acknowledge that our planning that we may have really goes for naught if we continue to devalue and underpay the world of EC So all our plans are rooted in that right there. Let's let's change that piece This is our story and it's unique to us. It's our context You have unique challenges you have unique stories to tell and so we will tell a story from Mildreni Valley That is not my story. It's it's a collective story.  You're gonna go play on the playground apparatus And the parents are saying to you that will be your school I'll suggest right now that it's already that child school and we need to open the door to that child before they turn the age of five And we need to have that child and and I think the child gets it I think we need to have adults understand that the playground the school in the classroom or the kids Doesn't belong to the adults, right? So there is a shift in mindset right there that we need to be following A lot of stuff will return on investment investment in child care child You know early years and so on there is so much out there that we have been doing like many other school districts I'm gonna talk about a couple things in particular where we might be playing outside the box a little bit First let's acknowledge that we do lots of great things in schools Our strong start programs have been amazing and I want to reinforce because I think we sometimes Understate the value of those programs that are as much about educating and informing and connecting parents to be better parents Which is foundational to everything because they are probably the most consistent adult in that child's life So those are really important and we operate some great strong starts I wish we could have enough money to pay for them, but that's another story Let's look it in we are also operating before and after school care on our school In our school buildings on our school grounds some of those are in partnerships with organizations community schools non-profits and so on and and those are working Amazingly and I will reiterate reiterate that piece this morning that if we have enough room for the kids between the bells We've got enough room for the kids before and after the bells We just got to find a way of making it happen And if that sounds overwhelming You know when we look at how many child children are actually going to access it We're not really saying a school of 250 has needs to have 250 spaces for it It's going to be a smaller number than that, but we shouldn't let that fear of being oh my god We can't do it stop us from starting so we started doing some of those programs We also have as many as you do childcare on And in our schools on our school sites some of those Really the majority of them are through lease arrangements with not-for-profits and other organizations who operate them on Our school sites what might be a little different is that the school district our school district is actually a daycare provider We hold the license for a preschool program, which in fact is illegal because If you read the school actors is one line in there that says that we aren't actually allowed to offer early learning programs except Giving prior approval from the minister now the minister actually came and visited it was awesome And he didn't tell me to shut it down. So I think tacitly that means it's okay to keep going and so So we are we operate that We're the license holder we hire the employee to And we pay that person $25 an hour because it's just a morally right thing to do and We also so it's it's meeting that demand for do you have additional space that we can access? Yes, but the really cool thing about that is we've also made that what we call the learning lab It's a hub where we have early childhood educators in partnership with North Island College They come and it's part of their early childhood program and they spend time in that environment as part of their ECE program So not only were we meeting space needs We're also looking at increasing capacity and those people who enter the ECE profession. So it's awesome And then we also had an earlier center for the past three years Which built some amazing relationships in our community multiple partners multiple agencies and so on and we lost our funding But we then got it back because we were successful in the process and we now hold the MCFD contract for the regional earlier services in our district and We're able to continue the work that we started years ago in our community and we have that regional approach now and To do that we hired Three individuals to provide leadership and management to it So we have three people in our district who are dedicated solely to the world of early learning It's not off the side of someone's desk. It's not part of another portfolio So our district leads Stacey medicine the principal is with us today I also have two others who are managers of our contract and so they breathe life into the MCFD contract They are also and I'm going to use the word pedagogist does for us because they are working with our community To engage with those who are offering childcare pre-k those who are in primary classrooms So it's learning its education its partnerships its collaboration and so on It's it's new to us but I think that group of amazing women are just rocking it for us and hands up to them You stand up and I have to finish And I just want to make it all really clear to everybody Okay, and we've also Created a bit of a stir out there a little bit of a ripple goes through our community Some people understand us and love us some people are afraid of us and reject us because the big systems come in to take over Ours is not about control. We seek no control over this We want to influence and we think we have some resources to help influence the early learning world And that's what we're trying to do So if it ever happens at the end of the day that it resides in the Ministry of Education right on and and if it means that people Are going to get paid the decent wage? Awesome. We just got to fund the thing right? But we've tried we're working outside the box We're building childcare and new buildings and everything else We'll come back and tell you how it went, but it's really a Rewarding piece because I am a secondary English teacher And for me who realized I'm way too far downstream This is the upstream solution. So thank you In 1998 a Coquitlam middle school community grappled with two worrisome issues a lack of after-school care programs for its kids and Some of its youth becoming involved in high-risk behaviors The community created a plan to provide its own after-school program to foster resiliency skills in vulnerable kids Secured grant funding and in January 2000 Kateslam from the Halka Malam word meaning coming together Began serving students at Banting Middle School Created to support indigenous youth. The program however was free and open to all Kateslam has grown over the years to serve three additional middle schools in 2017 the first Kateslam mini program opened at Glen Elementary. I have the honor of being Glenn's principal Glenn sits in the urban heart of Coquitlam and serves more than 520 students in kindergarten to grade 5 who speak 39 different languages We are indeed a United Nations of schools with a mosaic that represents many of the world's cultures Despite this diversity our community is united by one value It takes a village to believe to raise a child many caregivers in our village However, experience financial pressures complex work demands and difficulty securing child care as a school system our ability to mediate directly Those financial and work pressures is minimal But possibilities certainly do exist for us to significantly alleviate child care challenges and in doing so Indirectly alleviate the other pressures perhaps contributing to improved family mental health Kateslam is one possibility Its model is simple Utilize existing school district spaces and organizational structures to provide high quality before and after school programming for students Employ an affordable flexible not-for-profit fee structure provide nutritious hot breakfasts Hire safe caring and responsible adults who are trained in youth and social work Education or child development and psychology Deliver beyond the bells of the school day Evidence-informed programming designed to help children develop skills in self-regulation resiliency personal and social awareness and responsibility compassion kindness and curiosity Allow parents to meaningfully engage every day with their neighborhood school within the bookends of their work day and Bring schools and a community partner together to share in the work of supporting children and families to thrive Essentially Kateslam allows the Glen Village to provide its members with seamless care and education on a shoestring So what does Kateslam mini look like sound like feel like for the kids? It's arriving at school up to an hour before classes start Meeting friends and program staff in the community kitchen for a hot breakfast And then when the bell rings trendling off to meet their teachers later It's heading down the hall to the multi-purpose room to unite with program staff once again and begin working on homework Have a healthy snack and then pursue a mix of structured and unstructured activities such as crafts cooking reading games Toys outdoor play movement activities in the gym and of course special projects for families Bringing kids to a familiar building with safe trusted Staff before heading off to work and then picking them up from the same familiar faces and building at the end of the work day For Glenn school staff. It's collaborating with a trusted partner to best meet the needs of kids and improve their chances in life So why is Kateslam not in every one of our district schools? Well, we have met some obstacles to expansion We're currently navigating the dilemma of whether to seek licensing under the community care and assisted living act or to continue as a single Theme recreational program which does not require licensing this journey is proving is proving quite complex The expectations of the act as we've heard today are much different from those of the school act For instance the adult to child ratio and floor space ratios that are deemed safe for my Glenn students during instructional time Do not meet criteria for childcare Kateslam currently operates under conditions similar to those under which children learn with their teachers and support staff during Instructional hours, but a child care license would require greater numbers of staff and a lesser number of students Thus reducing our capacity to offer the program at the affordable costs that we currently do While the licensing officers in our community have been extremely eager to work with us The act currently allows them very little in fact no flexibility for exemptions on staffing and space ratios Predictable operational funding is another obstacle to expansion Kateslam which also offers programs in five other district elementary schools Succeeds because of the dedication and tenacity of its executive director Karen Bell She works tirelessly to chase down donations and grants that allow her to pay staff and the bills While charging a flexible and affordable rate to families I am able to provide safe space free of charge and we share costs on many of the operational expenses But this is certainly not a sustainable model when Karen retires Kateslam may well cease to be Recruitment and retention of staff is the final obstacle to expansion We are currently able to secure high quality staff willing to work at the minimum wage our shoestring budget allows Because they are so passionate about what they do However, this pool of human capital is limited and the level of expertise and experience required for this work Certainly deserves a higher wage an increase to our funding would allow us to recruit and retain enough high quality staff to expand I'm grateful for the opportunity to share about our Kateslam collaboration Thank you to all three ministries and I just wanted to end by saying I've been doing this for 27 years And this summit just leaves me so hopeful that together our greater provincial village will be able to come together to craft a system of seamless Care and education for all BC families to thrive. Thank you First of all, it's a we're starting out as a partnership with the Ministry of Education And they're offering us some support and some people and some critical friends as we work through this We have hired two amazing early childhood educators that are part of the district team one starts at 7 30 a.m. and Finishes at 1 30 in the afternoon. So she works In the kindergarten classroom in a in a program before and then stays in the kindergarten classroom When the teacher arrives at 8 30 to be a part of that team the second early childhood educator starts at 11 30 and Continues to work in the kindergarten classroom and stays until 5 30 p.m. So it's a seamless day Where there's overlap of two hours in the middle of the day and the two early childhood educators and our amazing kindergarten teacher Work collaboratively as an educated team to deliver an amazing well-rounded program for our kindergarten and grade ones and We're already finding out that the they're thriving together They're equals in there and the space is shared and the resources are shared and then during the End of the day because there are more than one kindergarten teacher involved They end their day every day with some outdoor learning and then when it's dismissal time Some children go off to their families and some return to the kindergarten classroom again in a shared space with shared resources and shared Supplies so we've are we're just beginning just backing up how it came to be I want to thank Maureen Dockendorf for showing me a video was 11 minute video From Ontario that showed the concept of this seamless day, and then we had a conversation about this Are you interested in trying some of this well? I've never been shy of kind of stepping out and trying something new But in this case I saw some amazing opportunities for our families and more importantly some amazing opportunities for our children and I had just the perfect classroom that would work in this situation because I knew a Teacher remember it's the it's the end of May That I could approach and of course she was on board and I want to just stop right now And I'm talking fast because I know only in five minutes and I have a lot to say But I just want to say that you know I certainly played a role in getting this off the ground and helping to create the vision in my district But the real work is happening in that kindergarten classroom with those ECEs And I want to introduce Malia Dirk at the back and stand up Malia If you want to connect with Malia She's the kindergarten teacher in that room That's taken a lot of risks and working out some bumps because we really hope we can leverage this to be on this one site So again, we looked at this video with Maureen Dawkendorf talked to Malia and then we I really wanted to work with our partner group So we have a partner group that already works in that school on some preschool programs Some before and after and I didn't want to come in as the big district. We're going to compete We're going to steal your ECEs So met with them talked to them about the vision and how can we work together to make this happen and not only were they Supportive we ended up really strengthening that partnership even more so because by us focusing on kindergarten and grade one they could focus on some of the older children and that was a Challenge for them to have a quality program that addressed Kindergartens and grade ones and then maybe up to you know 11 or 12 years old and then it allowed more people On the waitlist to get in so that really was positive and actually even more strengthened Our relationship and presented more opportunities for us So then I had to work with our QP Union because we had to create some new job descriptions We didn't have ECEs in a seamless day as part of our employment So we had to work with them in that and then I also had to work with our QP Union on agreeing to a letter of understanding Because we wanted some language agreement or language around bumping and leaves that wouldn't be good in this environment Particularly similar to what we have a strong start. So it was right in the middle of bargaining But we kind of could have these side conversations and again super super supportive and that worked really well with our our QP Union so then we put a posting out and Actually, we're worried about recruiting but we were able to recruit two amazing early childhood educators and then Put up we had to get licensed and I will tell you that I knew nothing about licensing and that was a really good thing in this case Because I'm not sure I would have treaded down I always see my job as a superintendent to try and keep the noise away from the people who really do the work and the principles and The teacher Malia so I said well I can I run a district I can go down this road and get this space license It's June and parents were signing up and really thrilled well That was a another process and you know, that's a whole nother story, and I still have a little bit of PTSD about that process but we got that place license with want just by losing one week and I just will suffice it to say that I needed less scrutiny to run a school district and As a superintendent and to work with my principal then I did at getting this one space license But we were able to get it licensed. I certainly felt the pressure of those parents They wanted in and they couldn't wait to begin and they had no plan B I was almost going to have them dropped off at my office at one point it I was actually not thinking very straight at one point because Everyone was so anxious to get this going But what are we already noticing in our humble beginnings of just a couple months in our parents are loving this program Not only do they love the one-stop drop-off, but they love the seamless day of policies We're starting to meet with our parents and they're telling us of the policies that are now in line with what happens during the school day Something we didn't even realize and they appreciate that they Appreciate that their children are coming home really connected and loving three adults in their classroom And the parents are saying that we feel connected in fact I come to the end of the pick them up and I get to hear stories about my child's whole day and the Eces know at the end what kind of day that that child has so parents are giving us such positive feedback we've We're consulting with Sharon Jaroski because we've agreed to do an evaluation piece of this around student outcomes So we're already meeting parents and telling them about the kind of outcomes around social emotional learning and attachment to adults and All the good things that we know makes a difference to connecting students to school and to Their teachers so we've started that Our ECEs are telling us that they are how thriving they are in this environment. Not only are they having Professionally a very satisfying experience, but they're talking about how they're growing professionally Working alongside an amazing teacher working with the framework of early learning in a way that makes them valued contributors to this educational team during the day


My name is A K Suresh and I am from the department of chemical engineering at IIT Bombay. In the next few lectures I will be talking about an important class of heterogeneous reactions namely gas liquid reactions. Now these are important from an industrial point of view as well as from an academic point of view. From an industrial point of view because industry uses these reactions for two important objectives one is to do a gas clean up for example removal of carbon dioxide from flue gases and removal of catalyst poisons such as H 2 S etcetera or carbon monoxide from gas streams which are to be subjected to any further reaction steps. And the second objective is to make products of commercial value such as for example absorption of sulphur trioxide in sulphuric acid to produce olium absorption of nitrogen oxides in water to produce nitric acid and so on. They are important from an academic point of view because there are more complex three phase systems or even more complex multi phase systems whose analysis runs in a similar manner to the analysis of gas liquid reactions. Let us provide some context so you can see where this class of reactions fits into the general landscape of reaction engineering that you have been seeing so far. When we study reactions we usually begin with the simplest class of reactions which is homogeneous reactions. Now, these are reactions in which everything is in the same phase all the reactants and products and catalysts if there are some they are all in the same phase and the reaction expressions turn out to be simple they are often of the type you know C A raise to m and C B raise to n type of rate expressions. Let us take an example such as reaction A in the liquid phase reacting with B in the liquid phase lower case B being the stoichiometric factor giving C also in the liquid phase. So this is the liquid phase reaction because the reactants as well as the product and if there is a catalyst the catalyst as well are all present in the liquid phase. Now such reactions you have seen before and they are often analyzed using expressions of this type and the analysis is simple the experiments to recover the values of k m and n are straight forward to setup and interpret and the design of reactions using these kinds of rate expressions is also relatively straight forward. Now the method of analysis that we use for these kinds of reactions can also be extended to simple heterogeneous systems simple heterogeneous systems as long as the species influencing the rate influencing the rate are in one phase. So what I am saying is in this reaction for example the rate expression contains the concentration of A and the concentration of B and as long as the as A and B are present in the same phase it does not really matter whether C is in the same phase or not it might volatilize being a volatile product or it might precipitate out of the phase. But the method of analysis is essentially the same as if C was also in the same phase however the matters get somewhat complicated when the reactants and catalyst if there is one are distributed among different phases. The simplest of so these are what are called as heterogeneous reactions as you know and the simplest of these reactions so let us say heterogeneous reactions and the simplest of these are those in which there is a continuous phase and there is a dispersed phase and there are just two phases. Now we have already seen the one class of such reactions which are gas solid reactions and in gas solid reactions you have seen two types one is catalytic in which case you model the diffusion in the pores of the solid catalyst and you recover a concentration profile of the diffusing reactant and use that to construct what is known as an effectiveness factor which is a factor that modifies the intrinsic rate. On the other hand you have also studied non catalytic gas solid reactions which further can be grouped into models in which or situations in which the reaction takes place at a front and this leads to the shrinking core type of models and you have also seen reactions in which the reaction takes place throughout the solid and these are these reactions are described by what are called as uniform reaction model uniform concentration models. In the catalytic reactions as well as the uniform reaction models we will call this U R M uniform reaction models as I said earlier you are modeling the concentration profile through the solid and for purposes of simplicity you can treat the solid particles to be spherical in shape and then you write the diffusion equation for a sphere get the concentration profile diffusion with reaction get the concentration profile and differentiate the concentration profile at the surface to find out the rate at which the reactant is entering into the solid which is the rate at which the reactant is being consumed by reaction. Now whether it is catalytic whether it is non catalytic whether it is shrinking core whether it is uniform reaction the point to be noted is that the reactions are in the dispersed phase the reactions are in the dispersed phase which happens to be solid in this particular case by contrast the type of reactions that we are going to study now which are gas liquid reactions are those in which the reaction is in the continuous phase this is because the normal situation with gas liquid systems is for example a gas being bubbled through a column of liquid which may be being stirred as in a sparged and stirred reactor or which may be being stirred by the flow of the gas itself such as in a bubble column also there are equipment such as packed beds and so on where also where you can say that there are both the gas phase and the liquid phase are continuous but the point is that the reaction is in the continuous phase which is the liquid phase. So here the although the although conceptually the issues are very similar to the case of gas solid reactions the method of analysis has historically evolved in a different way. What is considered for example in the case of gas solid reactions which I talked about a minute earlier is that the reaction is taken as the basic process there is a certain reaction that takes place at a certain intrinsic rate and the rate of that reaction is modified downwards that is it is decreased by the influence of transport factors by the fact that the transport is not able to cope up with the velocity of reaction under all circumstances. So there is an effectiveness factor which is which has a value less than one which multiplies the intrinsic reaction rate and you get the actual rate of reaction whereas in the case of the gas liquid reactions which we are going to consider now what is taken as the basic process is the process of mass transfer that is there is a gas there is a liquid there is a process of mass transfer that can occur whether or not there is a reaction that is taking place. But if this substance from the gas phase that is dissolving in the liquid phase has a reactant within the liquid phase to react with then the occurrence of the reaction will speed up the rate of mass transfer. So there is the basic process of mass transfer which is speeded up by the occurrence of chemical reaction contrast this with the situation in the heterogeneous catalysis case where there is the reaction which is slowed down by the occurrence of mass transfer or by the existence of mass transfer limitations. So this is a difference in perspective that needs to be understood because here we are going to talk about enhancement factors which have values more than one which multiply the basic mass transfer rate to give you the rate at which the gaseous solute is being consumed. So the basic process being mass transfer we need to understand the theories of mass transfer at least we need to revisit the theories of mass transfer because these theories provide a mechanistic basis and that mechanistic basis serves us in good stead when we want to include a reaction in the works. So there are basically two theories of mass transfer that we will consider one of which is called as the film theory and the second of which is actually a class of theory it is not a single theory and that class of theories we will call as the surface renewal theory. Now in what I am going to be talking from now on I am talking about the processes which are occurring in at any particular location in an equipment like this for the sake of concreteness let us take bubble column as our equipment. Now this is a cylindrical vessel such as this and gas is being continuously bubbled through and the liquid may be in continuous flow or may be sitting there getting converted it may be batch. So the gas inside the bubble column exists in the form of bubbles of various sizes and because of the churning action of the bubbles the liquid is in a state of agitation there is a state of turbulence. And what we are talking about is the events that occur at any particular position in the in this kind of an equipment for example say a particular location on the surface of a bubble at which absorption of the gaseous component A is occurring into the liquid. So the gas contains a solute A which is soluble in the liquid and so there is no reaction for now. So the A dissolves in the liquid and diffuses into the liquid that is the process that we are considering. So the first model that we will consider and additionally I must also mention that in such a process from your knowledge of mass transfer you know that there is a gas phase resistance and there is a liquid phase resistance. In order to keep matter simple we will assume that there is no gas phase resistance in the in the initial discussion. We will look at the consequences of including a gas phase resistance towards the end of the this set of lectures. So with those assumptions now we are ready to consider both types of visualization which have appeared in the literature. The first one as I said is called the film theory. Now in film theory the situation is assumed to be something like this. This is the gas liquid interface the solid line here is the gas liquid interface on this side is the gas this is part of the bubble and on this side is the liquid which is in turbulent motion. And what is assumed in the film theory is that the entire resistance to mass transfer is located in a thin film which is shown by as the region between the solid line and the dashed line here. So this is called as the film and outside the film the concentration of the solute or concentration of whatever there is in the liquid is assumed to be uniform by the and it is kept uniform by the action of turbulence. There is assumed to be an equilibrium at the gas liquid interface itself. In other words the concentration on the liquid side of the interface which I have called as C A star here is in equilibrium with the partial pressure of A on the gas side of the interface which is assumed to be known because we are assuming that there is no gradients in the partial pressure there is no mass transfer resistance on the gas side. So and this region this thickness of the film is usually denoted by the symbol delta the Greek symbol delta. And it is assumed that there is no turbulence or there is no motion of any kind within this region delta. In other words this film is assumed to be essentially stagnant and it absorbs the gas by a process of steady state diffusion. Steady state because irrespective of whether the entire bubble column is operating at steady state or unsteady state the film is always assumed to be in a state of what is called as quasi steady state. What it means is that because the volume of the liquid within the film is so small the contents of the film get adjusted to any changes that are happening outside on an instantaneous basis. And therefore the diffusing species always feels as though conditions are not changing conditions are study. So what we have said so far is that there is a film and the film is stagnant and the film is of thickness delta. And the diffusion process within the film is steady state molecular diffusion that is because turbulence cannot penetrate into the film. The effect of turbulence is only felt outside the film in the liquid bulk. So with these assumptions the governing differential equation is easy to write you can either make a shell balance as you have done for example in transport phenomena you can refer to the pages on mass transfer and burst toward light foot. If you need to refresh that part of the syllabus basically the continuity equation for a is given by d a d square c a by d x square equals 0 which basically says that if you take any you know in the film that I showed of thickness delta. This is the x direction that is the direction away from the gas liquid interface is the x direction and that the diffusion is assumed to be unidimensional unidirectional. And what we are saying here is that if you take a an infinitesimal element here of thickness d x then whatever is entering at this point must equal the rate at which material is leaving at that point because there is nothing no accumulation this being steady state and there is no reaction therefore, there is no consumption. So, this is the differential equation that that describes the transport of a through the film. In this d a is the diffusivity of a through the liquid dissolved a through the liquid. Now, this being a second order differential equation requires two conditions two boundary conditions in order to formulate it completely. And those conditions are given by saying that at x is equal to 0 which is the gas liquid interface the concentration of a is equal to concentration of a in equilibrium with the partial pressure on the gas side of the gas liquid interface. And at x is equal to delta the concentration of a is equal to c a b which is the concentration of a in the bulk of the liquid. So, this is a particularly simple differential equation to solve. And what it is essentially saying is that the second derivative of the concentration with respect to x is 0 if the second derivative is 0 the first derivative must be a constant and if the first derivative is a constant the concentration profile is a straight line. So, the solution to this equation is can be shown graphically in this manner. So, this is x is equal to 0 this is x is equal to delta and there is a straight line profile that stretches from c a star at the gas liquid interface to c a bulk at the edge of the film. The particular equation that this follows is c a equals c a star minus c a star minus c a b divided by delta multiplied by x. You can easily verify that this is a straight line it is linear in x and at x is equal to 0 this gives c a is equal to c a star if you put x is equal to delta c a star will cancel and you get c a is equal to c a b. So, it satisfies the differential equation it satisfies the two boundary conditions and therefore, this is the solution. What we are interested in is the rate at which gas is entering the liquid in the gas at the gas liquid interface and that is denoted by n a the flux of a in units of moles of a per unit area per unit time and this is given by minus d a d c a by d x which is fixed law. So, d c a by d x to be evaluated at x is equal to 0 because that is where we want the flux and d c a by d x is evaluated in a straight forward manner from the linear equation. And we obtain if you did the simple differentiation you will get this equation let me write that again n a equals d a divided by delta into c a star minus c a b compare this with the usual way in which mass transfer into turbulent liquids is described in terms of a mass transfer coefficient and a driving force. And comparing these two we arrive at the interpretation of the mass transfer coefficient in the film theory paradigm as k l is equal to d a by delta. So what this says is that the mass transfer coefficient varies in direct proportion to the diffusivity of a in the liquid and it varies in inverse proportion to the film thickness. In spite of its appearance this is not an equation that you can use to predict the value of k l because the value of delta is unknown. All you can say is that the stronger the turbulence the more intense the turbulence the thinner is the film expected to be because turbulence can now reach closer to the interface. Beyond that it is very difficult to calculate a value of delta given the conditions of the you know let us say power input or whatever in the into the liquid. So this equation is as much a definition of k l as it is a definition of delta. So there is no way in which you can calculate a value of delta and therefore, calculate a value of k l. This should be taken as saying that the only way to calculate delta is to actually measure the mass transfer coefficient experimentally and use this equation to calculate delta. So then what is the use of this equation? It makes one testable prediction that the mass transfer coefficient is proportional to d a. How does this prediction bear out in practice? It turns out that the diffusivities of gases in liquids do not vary over a very wide range. So it is not the most straightforward of matters to actually test this equation rigorously. But available data indicate that k l is actually proportional to d a to the power n where n has a value that varies between 0.5 and 0.67. In other words it is less than proportional to the value of the diffusivity. So this is what experiments indicate to the extent that we can make out what the experiments are saying. So now let us proceed to the second theory and this as I said is not a single theory. But this is known as we will call this as surface renewal theories and we will make use of this nomenclature surface renewal to indicate that the picture of the gas liquid interface in this theory or in this class of theories is something that is constantly being renewed. So material from the bulk of the liquid is constantly being brought to the interface and is constantly being removed from the interface and mixed into the bulk. So in this surface renewal theory under this heading of surface renewal theories we will consider two variations one due to Higbee and the second due to Dankwurz. The Higbee version of the surface renewal theory is also called as penetration theory and Dankwurz's version of the theory is simply called as Dankwurz's surface renewal theory. So irrespective of whether we are talking about the Higbee theory or the Dankwurz's theory all surface renewal theory I mean there are other versions of the surface renewal theory as well. But these are the more classical ones and it is enough for our purpose to really understand these two theories because as we will see later there is no qualitative difference between these theories and various other theories that have later been proposed. So irrespective of whether we are talking about Higbee theory and the Dankwurz theory the development is identical up to a point and it is only at the late stages of the theory that we have to invoke an assumption which will distinguish the Higbee theory from the Dankwurz theory. So let us proceed with the development here what is assumed is that the picture at the gas liquid interface is something like this. So here this bold line once again is the gas liquid interface which is part of the surface of a bubble as we have considered earlier. So what is assumed here is that the liquid bulk which is in a state of constant churning because of either agitation or because of gas flow or other means of creating turbulence and the action of this turbulence is essentially to throw elements of liquid onto the surface that is what this arrow indicates. So elements of liquid from the liquid bulk are thrown onto the liquid gas liquid interface and once there they spend a length of time which we call as the residence time of the surface element and at the end of the time they are removed from the surface and then recycle to the bulk. While they are residing at the interface they are in direct contact with a surface element is in direct contact with the gas phase solute which is on this side and the gas phase solute we have called A and A has a concentration of C A star at inside the inside the element at the gas liquid interface. In other words what we are saying is that the moment the liquid element lands at the gas liquid interface the interface achieves equilibrium with the gas phase and from there on the solute tries to diffuse into the liquid into the liquid element for as long as the element is at the surface. Once the element leaves the surface it is mixed up with the liquid bulk and the concentrations are evened out. So while the liquid element is at the gas liquid interface what is taking place is a process of unsteady state diffusion instead unsteady state Fickian diffusion. Contrast this with the situation earlier where the process that we considered was a steady state Fickian diffusion process. So and we are saying that on the microscopic scale at any particular location at the gas liquid interface the process is an unsteady state Fickian diffusion process irrespective of whether the macroscopic process in the entire equipment is taking place at a steady state or unsteady state. This is to be clearly understood because we are here talking about local rate phenomena only. So that is what the concentration profiles shown as dashed lines here indicate the as time progresses as the element spends more and more time at the interface the concentration profiles proceed into the liquid in that manner. So what is the and also another important assumption here is that the time for which the liquid element resides at the interface is so short that the and the penetration of the geyser solute so small that the penetration is confined to a region that is close to the interface. So for all practical purposes the liquid element may be considered to be infinite in depth. So what is the governing differential equation then? So we have to write the unsteady state balance for a and that is shown in that manner. It is the same equation except that the difference in the input minus the output for any differential element is equal to the accumulation here because we are considering an unsteady state process. So here x is that direction away from the interface as before. So this is now a partial differential equation first order in time and second order in x and therefore we need an initial condition and two boundary conditions. The initial condition is specified by saying that at t equal to 0 the concentration at the concentration everywhere within the element is equal to the bulk concentration. So at time equal to 0 the element has just landed at the gas liquid interface and throughout the element the concentration is equal to the bulk concentration which is where it came from. At t greater than 0 we have the first boundary condition at x is equal to 0 we have c a equal to c a star. In other words what we are saying is that the moment the element arrives at the interface at the gas liquid interface the concentration achieves equilibrium. And at t greater than 0 as x tends to infinity remember that the element can be considered to be infinitely deep because the gas does not get to penetrate anywhere near the far end of the element. So as x tends to infinity the concentration is unchanged it is the same as what it was at the beginning of the process. So this is the differential equation and the governing this is the governing differential equation and the initial and boundary conditions. Now you might have seen these kinds of equations in your transport phenomena course again either in momentum transport or heat transport or mass transport. And these are amenable to solution by a technique called as similarity transformation. What you notice is that the conditions at t equal to 0 and x equal to infinity are identical at t equal to 0 the concentration is equal to c a b for all x at x equal to infinity for all time the concentration is once again equal to the same value. This suggests that you might be able to define a variable which is a combination of x divided by t to the power alpha such that the by replacing by doing the transformation in terms of this combined variable we will be able to eliminate t and x completely and have a single ordinary differential equation in terms of xi alone. So you can see that the basis for this comes from the fact that this works for an equation of this kind number 1. And number 2 whether x is equal to 0 or whether t equal to 0 or x is equal to infinity xi has the value of infinity and at that value the concentrations are the same. So the value of alpha which makes this transformation work can be calculated by substituting this into the differential equation. And then find looking for such a value of alpha the so that x and t do not occur except as the group of x divided by t to the power alpha. It turns out that the value of alpha that does the job is half or you can deal with a variable of the type x divided by root t and in order to eliminate some constants what is normally done is this variable is used in order to transform the partial differential equation to an ordinary differential equation. Now I will not go through the details of the derivation this can be if you substitute this into the differential equation here it gets transformed to an ordinary differential equation which turns out to be fairly simple to solve. Now once you have done that you got an equation for concentration which is an error function. So it is actually C A minus C A bulk divided by C A star minus C A bulk equals error function complement of x divided by 4 d A t. This error function complement is nothing but 1 minus error function of x divided by 4 d A t and error function itself is defined as 2 by root pi 0 to u e to the power minus let us say t squared d t. So that is the definition of error function. So error function is a tabulated function you will find this for various values of u tabulated in mathematical hand books. So you have got this as the concentration profile and if you plot this concentration profile for various values of time you will get a picture that is something like this. So you have x and all concentration profile start with C A star as soon as the element lands at the interface it has a profile that is something like this that is a t equal to 0 at larger values of time you have concentration profiles developing in that manner as t increases. From these concentration profiles we can calculate the instantaneous rate of absorption in a surface element which has spent let us say t seconds at the interface. We do this by applying Fick's law as usual except that in this case because we are dealing with a concentration profile that is a function of x as well as t we have to use the partial derivative of concentration with respect to x evaluated at x equal to 0. So we do this as follows we have the concentration profile as given by this expression here if we differentiate this we get d C A upon d x we have to differentiate the error function here. So we get first of all C A star minus C A B and as usual we apply the chain rule of differentiation differentiate the error function with respect to the argument and then differentiate the argument with respect to x. So when we do that the first differentiation of the error function with respect to the argument is simply the integrand itself evaluated at the upper limit. So we get that as 2 by root pi e to the power minus x squared divided by 4 d A t and differentiating the argument with respect to x we get 1 by square root of 4 d A t. So the 2 will cancel with the square root of 4 here and this whole thing has to be evaluated at x equal to 0 which means that we get there is a negative sign as well coming from the fact that we have the error function complement and so we get minus C A star minus C A B 1 over root pi d A t and substituting this in that expression over here we will get N A i of t as square root of d A upon pi t C A star minus C A B. So this is the rate of absorption in an element which has spent let us say t seconds at the interface. So now let us step back a moment and take stock at what we are trying to do. So we started with an operating piece of equipment such as the bubble column and then we said that we want to understand the local phenomena which are taking place at any location in this bubble column let us say at a particular point on the surface of a typical bubble. Now we are saying that even that particular point on the surface of a typical bubble is itself composed of several thousands of these what we have called surface elements and each of these elements has spent a different length of time absorbing at the interface. In other words the interface itself can be pictured you know this particular location on the surface of a bubble that we are talking about if I want to spread that out in this manner then it is nothing but a mosaic of surface elements which I can picture like this. Some of these surface elements might have just arrived some of these might have arrived a little earlier and so on and there are those elements which are about to leave right. So there are short lived elements there are I mean there are elements which have just arrived there are elements which have been absorbing for some time and there are elements which have been there a long time. So what we have calculated on the previous slide is the absorption rate in a typical element of this kind which is of age t. So this absorbs we said at this rate. Now if you want to calculate the rate at which the entire surface is absorbing then we need to know what part of the surface is how old. In other words what fraction of the surface elements that make up this unit interface has spent what length of time at the interface. So in order to do this we define the age distribution function I of t d t which is the fraction of all surface elements of age t to t plus d t. If we define this internal age distribution as it is called then the average rate of absorption by the entire surface or average flux of absorption is given by integrating the instantaneous rate of absorption with respect to time weighted with the internal age distribution function. So what we are saying here is that this is the rate at which an element of age t is absorbing and this is the fraction of the surface which is of age t and therefore the average rate of absorption of the entire surface is given by this expression. Now what do we use for this function I of t. So this is where the difference between Higby theory and Danckwert's theory plays out. So we will consider these two concepts one by one. So if we consider the Higby's version of the surface renewal theory what he said was that every element of every surface element every surface element spends exactly the same length of time at the interface spends the same time and let us call that as t b at the interface this is the central assumption. So if you look at this assumption this is what happens in plug flow an element enters into a plug flow environment spends exactly a preordained amount of time which is decided by the volume of the plug flow environment divided by the volumetric flow rate and then it leaves. So since every liquid element is spending the same length of time at the interface. So as we have said this is similar to plug flow we can use the internal age distribution of a plug flow environment for I of t dt in order to calculate the average flux. Now if you go back to the residence time distribution theory then you will recall that for a plug flow vessel for a plug flow environment the I of t function has this form it is 1 over t b for t less than or equal to t b and it is equal to 0 if t is greater than t b. Graphically this looks something like this if you are plotting I as a function of time there is a time t b and this is the kind of distribution that we are talking about. There is nothing of age greater than t b and less than t b for every age there is an equal fraction. So this is what is the internal age distribution for a plug flow vessel and using this we can calculate N a as N a I which is square root of d a by t multiplied by the internal age distribution and integrated from 0 to t b because outside of t b for all times greater than t b this function is 0. So this is quite easy to evaluate I have forgotten the c a star minus c b c a b which is of course there. So what we get is 1 over t b square root of d a by pi c a star minus c a b integral of 1 over root t d t 0 to t b. So if you perform this integration the result is square root of 4 d a by pi t b into c a star minus c a b. Comparing this with the usual mass transfer rate expression we find that the mass transfer coefficient in this theory is interpreted as 4 d a by pi t b. So this has 2 things to say that k l is proportional to square root of d a number 1 and k l is inversely proportional to 1 over square root of the mean residence time at the interface. Now Higbee was led to this model by consideration of a single bubble that rises through a quiescent column of liquid. So if you have a quiescent column of liquid and let a single bubble rise in such a column then it is easy to imagine that for every bubble new liquid meets the bubble at the north pole slides down the surface of the bubble and disengages from the bubble at the south pole. So if this is the kind of manner of contacting between gas and liquid then you can calculate that the time for which the gas is in contact with any element of liquid is nothing but the diameter of the bubble divided by the rise velocity of the bubble. So for these situations you can actually calculate t b from these kinds of considerations and plug it into this expression here and therefore you can actually do a prediction of k l. So if you do that it turns out that the results are quite in accord with the experimental data and this equation bears itself out quite creditably. But you can do this kind of a calculation of t b only for very simple situations such as this and the actual situation in an operating piece of process equipment is far more complex. The bubbles are do not rise in a single straight line they are moving in zigzag ways all over the place. The liquid is not quiescent the liquid itself is in turbulent motion and in addition there are coalescence and d d dispersion processes to which the bubbles are subject. So in this kind of a complex situation it is not possible to calculate the value of t b from first principles. So we should regard in those kinds of situations the equation as providing a definition for t b as much as the equation provides a definition for k l. In other words what I am saying is t b is to be regarded as a fitting parameter to be calculated from experimentally measured values of k l. So if that is the case then this equation leaves us with just one testable prediction that is k l is proportional to square root of diffusivity and as we have already remarked at the beginning of while dealing with film theory this is quite in accordance with experimental data. So experimental data do bear out that the mass transfer coefficients are proportional to something like the square root of diffusivity. Now let us look at what Danckwerts had to say about the surface age distribution and how the predictions of that theory are different from the Higby's theory. So Danckwerts's surface renewal theory. So what Danckwerts said was the Higby's concept of plug flow of surface elements and every element spending an exactly equal length of time at the interface is alright for very simple situations as single bubbles rising through the a quies and column of liquid. But in actual operating pieces of equipment the situation being far more complex elements of liquid are landing randomly at the interface and they are randomly being taken away from the interface. So the situation here is far more like in a well mixed vessel and very different from what it is in a plug flow vessel. So he said that why do not we look at the gas liquid interface as though it was a well mixed environment. If that is the case we turn back to the residence time distribution theory and see what it has to say about the distribution of internal ages for well mixed environments and there we come upon this kind of an expression I of t for a well mixed environment I of t is given by 1 over t b e to the power minus t upon t b or this is written in the language of Danckwert's theory in that manner where S what Danckwert's called as a surface renewal rate is nothing but the reciprocal of the mean residence time. So that is the internal age distribution that we have to use in conjunction with the instantaneous rate of absorption in order to predict the average rate of absorption which therefore for this theory takes on this form d a divided by pi t that is the instantaneous rate of absorption multiplied by S into e to the power minus S t d t the whole thing integrated from 0 to infinity and we have to add the driving force term which is part of the N a i t d a pi pi t under the square root multiplied by C A star minus C A b. So when we do this so this you know if we take the constant elements out then we see that it is nothing but square root of d a upon pi C A star minus C A b into S integral 0 to infinity 1 over root t e to the power minus S t d t. Now the simplest way to evaluate this integral is to recognize that this is nothing but the Laplace transform of 1 over square root of t. So if you look up the Laplace transform of 1 over square root of t from a table of Laplace transforms and substitute we will find that this amounts to root of d a S multiplied by C A star minus C A b. Comparing this with the mass transfer rate expression we find that the Danckwert theory predicts K L as being able being equal to square root of d a S. So we have this and we have the earlier expression due to Higbee and if we compare this and this two things are obvious. One is the square root of d a dependence is there in both of them and in fact if you look at the way in which we are doing these integrations it does not matter it does not matter as to what you assume for this function i f t d t the square root of d a dependence comes from within the expression for n a i f t and therefore that is not going to change irrespective of what you substitute for i f t d t. So it is not surprising that both Higbee and Danckwert's theory predict that K L is proportional to square root of d a and in that respect therefore there is nothing to distinguish one theory from the other. As to the other prediction of whether K L is inversely proportional to square root of t b both of these do predict an inverse proportionality between square root of t b. There is a constant here that is not very different from one which is the only difference between the Higbee's theory and the Danckwert's theory. So all in all there does not seem to be very much that distinguishes the Danckwert's theory from the Higbee theory especially when you consider that this t b is something that cannot be measured from first principles and therefore the only way you can fix t b is to actually go back to a measured value of the mass transfer coefficient. So we will conclude this section by making some concluding remarks on the two theories that we have seen under the surface renewal category. The first remark we make is that in the surface renewal theories it is a given that K L is proportional to square root of d a and in that respect these theories are better than the film theory which predicts that K L is proportional to d a to the power 1 linearly proportional to d a and the second thing is that the Higbee's theory and the Danckwert's theory are somewhat similar in terms of their quantitative predictions of the mass transfer coefficient there being a difference of about 10 percent if the value of t b is exactly known. Given that the value of a t b is not known and it can only be obtained from experiments there is you can say that the Higbee's theory and the Danckwert's theory are virtually saying the same thing. The third point is if that is the case and the Danckwert's theory seems to be more complicated in terms of the internal age distribution function it uses why worry about the Danckwert's theory at all. The real advantage of the Danckwert's theory is mathematical advantage is nature of Danckwert's theory surfaces when you have got linear systems to consider such as the simple mass transfer problem that we have considered so far that arises when you look at this integral here and we made the point that the way to evaluate this integral is to recognize the parallel between the averaging process that is going on here and Laplace transformation. So, what this suggests is that if you have a situation in which the governing equations can be solved by Laplace transforming the equation remember that the governing equation in the surface renewal theories is always going to be a partial differential equation and one of the techniques of solving partial differential equations which are linear is to Laplace transform the equations with respect to time and eliminate time and convert this to an ordinary differential equation. So, if you use that technique and get the equation in the Laplace domain as an ordinary differential equation and solve it then the required quantities which are the flux the concentration profile etcetera the average concentration profile etcetera can be obtained without actually inverting the transform to back to the time domain and you can work in the Laplace domain as itself and directly obtain the results. So, this gives you an advantage in terms of the mathematical aspects of solving the differential equations that arise. So, we will conclude by summarizing the important aspects of today's lecture. So, we consider the problem of mass transfer or what we may call as physical mass transfer because there is no reaction here into an agitated liquid. Experimentally this situation is always explained using in mass transfer coefficient and the usual way in which the absorption flux is written is to invoke a mass transfer coefficient and a driving force of this kind. So, this is how experimentally we describe the physical mass transfer into an agitated liquid. So, we considered two theories one is the film theory and the film theory said that K L is proportional to diffusivity. We considered the surface renewal theories and the surface renewal theory said that K L is proportional to square root of diffusivity. Now, this is more correct when you look at the evidence that is available of the way in which the mass transfer coefficient depends on diffusivity and this is not so correct. However, the advantage here is that there are ordinary differential equations to solve and here there are partial differential equations to solve. Therefore, from a mathematical point of view if we can use this theory based on some consideration it is going to be always easier to solve. So, we will keep that in mind and in the next lecture when we take up the effect of chemical reaction on the mass transfer rate. We will first do our deliberations in terms of the film theory. We will disregard for the moment that the film theory is less realistic as compared to the surface renewal theories. We will assume that the film theory is a model that is acceptable in some sense and then we will look at the effect of chemical reaction on the physical mass transfer. We will go through the development and then we will see how the development will differ if we were to use surface renewal theories. Then it will turn out that if all you are interested in is the is in predicting the effect of mass transfer effect on effect on mass transfer of the chemical reaction then one theory is nearly as good as another. Having said that there are some kinds of reaction for which the surface renewal variety of theories will give you a better prediction as compared to the film theory. So, we will come to those aspects as we go along, but I have made these comments just to justify my use of the film theory in the initial sections of the consideration of chemical reaction and its effect on mass transfer.


Thank you for your interaction. Okay, good afternoon, everyone. And thank you for giving me the opportunity to be here to share my experience with you. I hope that at the end of my talk, you will be familiar with the pharmacovision system in Thailand and also know how pharmacovision and pharmacogenomics work together. I have divided my presentation in three parts. The first is the overview of the Thai pharmacovision system. The second is the Thai vigilant based pharmacovision data bed. And the third part is the pharmacovision and pharmacogenomics research. For the overview of the Thai pharmacovision system, I classify it into levels. The first level is the national level, the pharmacovision network and management. I classify it into levels, one with the national level and the second is the hospital level. And another part is the surveillance methods utilized in the pharmacovision. We do both passive and active methods. Let me introduce a little bit about Thailand. Thailand is a country in the Southeast Asia with a population of 65 million people divided in the 77 provinces. Pharmacovision was active in 1983 and the National Center was set up as a part of the Thai FDA at the same year. The year later, Thailand joined the official program for international drug monitoring as the 26th member in 1984. Right now, I think it's about 100 countries. This slide shows our network and the management at the national level. Someone called is the medical pharmacovision. Hospital is our main source of reports. About 1,000 to 1,500 setting reports to our center each year. Their reports are voluntary, not mandatory. But anyway, most of them are government hospitals and the government has the policy for them to report to us. For the company of marketing authority, it's mandatory for just early the new drug according to the safety monitoring program. And all the data that we analyze, if the signal is detected, it will proceed to consider the pharmacovision especially community to consider whether any measure should be implemented. For the communication measure, we can do immediately. But for the regulatory measure, we have to get the adoption from the drug community. Then Thai FDA will do the enforcement for that recreation. The AERI reporting system is the main system that the hospital used to report to us. Anyway, the other methods are welcome such as email, fax, seminal, and post-paste mail. Every month, we will send back the letter to acknowledgement and to inform how many reports that we receive from each hospital or each company and inform how the quality that they send to us. Each report will be classified by the component of the report. And for the routine, we will have a drug bulletin and also each year we will do the annual report. And in some situations, some of them will be feedback to the reporter. This safety monitoring is a condition for the new drug application only. So during two years, this program will be conducted for two years. During these two years, the company has to do the ADR monitoring. So they send us the report.  Now let's move to the hospital level. In the hospital, pharmacies pay the major role in this activity. When there is an ADR diagnosis, pharmacies will be notified to collect the data and do the assessment. Physicians in Thailand don't want to fill in any report. So pharmacies take care of this job. And after they do a causality assessment, they will feedback the result to the physician. Sometimes they have a discussion whether to agree with the result or not. At the same time, pharmacies will send the report to our center and try to minimize the risk by several methods. For example, they will provide the dark alert card to the patient. This card will document the suspected drug name, adverse drug reaction, and causality assessment level, and also the reporter. And recommend the patient how to use this card because it's very hard for the patient to remember the name, pieces, or English name. So we recommend them have to take this card every time when they see the doctor. Sometimes when the pharmacies will do the causality consultation, to do the patient consultation, to the patient who receives the medicine that can induce the serious cutaneous adverse drug reaction, this is the book for them. And this slide shows several many methods that we use to try to minimize the risk. This is the sticker to inform that this patient developed adverse drug reaction, this patient charge, medical record, and also patient bed. Some of you may have a question why we add on so many pairs because we would like to convey this message to the one who should know about that. And the information about it also input in the dispensing program to alert when the doctor prescribed the same medicine with the same patient who experienced the adverse drug reaction. Then the pharmacy will call back to confirm whether the doctor still would like to prescribe that medicine or not. The causality assessment method that the pharmacies use is the same as the USFDA, which is the old Uppsala monitoring method, and also Nalangzhou algorithm, and also the Thai algorithm. The Thai algorithm is modified from the visual UMC. For the surveillance method that we use, we use both passive and active methods. For the passive methods, spontaneous reporting is the main method that for all drug. And for the targeted spontaneous reporting is for some safety concerns or some drug of interest. For example, it's conditional approval new drug or herbal medicine, which is the national essential drug lead, and the medicine used in the public health program such as NGTB drug or ARV. For the active surveillance, the intensive hospital monitoring will be conducted for some products only. And I hope that this year or next year, the cohort even monitoring will be implemented for the new drug of NGTB. And for the registry, we conducted only one project. Because Thailand has a problem that the incident of the peerless aperture associated with illiteracy is higher than the other country in the world. For the type which way I will classify as shown on the slide. This slide shows the characteristics of our database. Right now, about 6 million reports were accumulated. Over half of them have been received in the last six years. About 50,000 reports were received each year. Only 2.1% of the reports were submitted by the company. Most of them come from the hospital, and about 20% of serious cases were received. During 1984 to 2014, about 18,000 reports were received. We can classify as HHS is the most adverse drug reaction that we receive. For the epidemoniclysis is the preferred term of the toxic epidemoniclysis. We use the base O, who are different from the beta. Similar, but not the same. But the pacification is the same. This slide shows the Steven Johnson syndrome. The total HHS and 10 report is 11,000 right now. The proportion of this report in Taiwee Tibet is about 1.8. This is the characteristic of the report. About half of them rank at the probable level. And 2% of them have a dead outcome. This slide shows the more suspected drug associated with HHS and 10. I think it's similar to the US FDA. And this slide shows the signal that our report contributes to generate signals. Two of them is Steven Johnson, this PTU. The number, this is five reports come from Thailand, from 12. And this is the signal generation that do by our Thai FDA. We found the steptomycin associated with the Steven Johnson syndrome in 2013. This slide shows the report in our last bed. Consistence with the publication from Africa. That indicated that an increasing list of the serious, serious cutaneous reactions associated with the use of the Taiwee acetalzone in person who with HIV. So, at the same time, our data can detect the signal. Even though the report didn't mention that this patient is HIV patient or not, but at the same time that the HIV epidemic in Thailand. This is public in the debate or within. For the research and publication that you see in our database. This is our colleagues' thesis. We evaluate reporting serious adverse drug reactions in Thailand against study of HHSN10. The study is a cross-sectional study. We select 14 selected hospitals from five legions of Thailand. We compare the report that our center received in 2005 compared with the report. How can I say? The ICD-10 compared to the report from this hospital. We retreat the case by using the ICD-10 computer-like system. And then verify with the patient medical record. The results show that the under-report is about 44 percent. And this cut-dance submission is about 8 percent. This slide shows the publication that you see in our database. Both of them. And now let's move to the last part. This picture shows our campus. And this one, even if I'm not here, but from the Dr. Wasan picture, confirm that I was there. And from the brainstorming, we found that the association between HHSN10 confirmed. And we estimate that if we... about 90 percent can be prevented by screening tests. So from the brainstorming, there are several... even come out. One is the proposal for the universal screen for carbamazepine. And they need the economic study. And also they need to develop the pharmacogenomic testing center. And at the same time, the pharmacogenomic network has been conducted. From the result, the testing for the neuropathic pain is not effective, but not for the epilepsy. Epilepsy is a borderline. And this is the nice center of the pharmacogenomic testing. And three-day quarantine turns around time for this service. And this slide shows the first announcement for the nationwide pharmacogenomic service. And the pilot-free testing for the all-carbamazepine presky in Bangkok. And for the study, 18 hospitals, which is our pharmacovigilane network, participate in the thyska pharmacogenomic-fed one study. And this slide shows how our center participates in this study. Every week, one of my colleagues will detect the case. And then inform the researcher, Dr. Sulakamed. And this slide shows the number of DNA samples collected based on the suspected drug. And I show this slide again because someone may think that because of carbamazepine testing, they do the case, but I think we have to find out. Further research have to conduct. I will end my talk with this slide. The collaborating with the pharmacovigilane team and pharmacogenomic team not just only benefit each other, for my opinion, I think it's benefit for the patient's safety as well. Thank you for your attention. And thank you, Dr. Sulakamed, for preparing the third part. Great. Thank you very much. Yes, Dr. Leader. That was very interesting. I noticed on a couple of slides one in the reported cases that the number of reported cases of cotrimoxazole, trimethoprimsulfa was exceeded considerably that of carbamazepine. And also in your collected DNA samples, you had a lot of cotrimoxazole samples. Do you think that's a function of an increased susceptibility in the Thai population, or does that reflect a use that's greater than what we might use in North America or Europe? I passed this to Dr. Sulakamed. Okay. I think there are several factors. First, we use a lot of surfamethoxazole because we have HIV epidemic. And this drug is used for opportunistic prophylaxis before we have a national antiretroviral program. So we have a lot of cases five, ten years ago back to more surfamethoxazole is recommended for the one who cannot afford the antiretroviral. So at that time, we use a lot. So we have a lot of cases with adverse drug reactions. And the second is that surfamethoxazole is the highly suspected drugs. When we treat the HIV infected patient, we usually give them multiple drugs. And then if you have multiple drugs and the pharmacist or the physician has to pick the causative drugs, then it will be the highly suspected. So it's become the first one. So every time we, I mean, anyone reported it become the first one that pick it to be the suspected drug. So that's the second. And the third one, we found some association with HLA class one with this surfamethoxazole in Thai population. And we are trying to publish the data. And probably we have some specific association with some HLA and Liu. So maybe these are the explaining factors. But it's the combination of surfamethoxazole and trimethoprim that you're giving? Or is it a combination? Yes. Is there much use of trimethoprim alone? We rarely use it. We usually use them together. I confirm that when pharmacists always think that south farm medicine is the suspected drug for the student and student. So the HLA always is the suspected drug for that report. I wonder if maybe Dr. Sirakameth or others could comment on the interaction between Stevens Johnson and HIV AIDS. And that it seems that patients with AIDS are at like, you know, a thousand fold increased risk. Or so particularly when their CD4 counts are low. Do you want to comment on that? So we have also the developing, which is the another drugs that cause Steve intense in our populations. And yes, we observed that Steven Tennis has a lot of hybrids in HIV population. But we do not know exactly why. So maybe it's a topic that we can study. Yes, Dr. Malkin. We used to have, we used to see a central number of cases related to never opinion, especially in France. And we had some suspect that at some point maybe patients of African origin may be more susceptible. We could not really prove that. But these were people living in the greater area of Paris where you have a higher population, deriving from these countries in Africa. But ever since there's other alternatives, we hardly see cases of the never opinion in Europe and central Europe. Our colleagues from South Africa report a completely different picture. The majority, this is let's say a governmental hospital run by the government. So everyone comes there, the poor people as well. Most of them are HIV infected plus have tuberculosis. So that means they have six, seven drugs, three or four for each of the conditions. And it's very difficult to identify the culprit one because they are kind of started pretty much at the same time. And they have developed a certain protocol how to deal with it. Because sometimes it's not easy to say whether it is one of the anti TB drugs or of the HIV drugs. So they stop everything and then step by step reintroduce the drugs. Because otherwise they would risk that the germs would be not sensitive to any medication anymore. So these are probably the people who could talk about this best. But of course, none is here right now. So in our prospective court study in Malawi, we followed a thousand patients from initiation of virupine for at least six months afterwards. At that time, the policies were not to start anti tuberculosis therapy at the same time. So these patients were started on triple therapy in terms of the virupine as Zidavidine and Stavidine at that time. So that because of the high risk of these hypersensitivity syndromes, the Malawian Ministry, National Health Ministry has changed the drugs now. If Averins is the commonly used drug, Stavidine is also gone because of peripheral neuropathy. But when we have done the work and this is also seen in northern European populations, the actual risk factor in terms of CD4 count is that you have to have a high CD4 count greater than 250 to be able to get the Stephen Johnson syndrome. I guess the pathogenetic point of view from that is that if you have too low a CD4 count, you don't actually have the immune system to be able to generate an immune response to start killing you off your skin cells. Just to follow on that, there is some data that also suggests with neuropeners. I think there's three or four separate studies that suggest in patients that are switching with undetectable HIV viral load that they don't get the reaction. So if they're virulogically suppressed or HIV is controlled, they don't seem to be at higher risk regardless of their CD4 count. So I think that's interesting. I just had a second question just regarding geography of Thailand and the diversity within it. I know northern Thailand has a lot more higher prevalence of specific Caucasian HLA alleles like HLA B5701. Do you see any signals across the country in terms of actually differences, potentially in terms of reporting of specific drug reactions based on that diversity? I'm not sure I get your question, but is this about the geographical distribution? Northern Thailand has different HLA representation like certain HLA B alleles like HLA B5701. The carriage rate there would be as high as 10% just like in Europeans. We did the determination of the regional distribution of HLA B specifically. And 1501 has a northern-souten gradation, but it's not so large difference. In the northern, we have like a 6% or something and then in the southern, we have 10%. But that's the only frequency. So if it's a carrier, it's turned out to be 12 to 20 ranging from the northern to the southern. But the southern has higher rate of prevalence of 1502. But for the 3505, it's about 3% distributed all over the country. There's no specific difference in the region, but the Indonesian population has a lot higher 35% or 5%. But then I think the question is, do you see a geographic influence of rates? I mean, I guess the numbers may be too low to see, but do you see different rates of SGS10? We don't see that, I think. What actually happens with regards to like health care in Thailand where patients access care as opposed to where they're from? There were two maps that we represent. And the first one is NICE Center for Pharmacogenomic Testing. And the other one is the 18 hospitals that participate in collecting the examples for these Stephen 10's cares. So that 18 hospitals is voluntarily working with us. So they are the hospitals that have adverse drug reaction pharmacists. So these pharmacists are interested in Stephen 10's more than the others. So they work with the patients and they get the sample for us to test in the research. And another thing is most of these hospitals are tertiary hospitals. So the Stephen Jensen case always refers to these hospitals. Dr. Wimun, could you go back to the slide, your wish base? The one that did. The one that from 2010 and then dropping the Stephen Jensen cases. Because one of our objective is to try to eradicate Stephen Jensen and 10. So in Thailand, can I say that now we are approaching that mode of eradication? And my question is what is the cause of dropping of Stephen Jensen and 10 because of the pharmacogenomic screening or because of the pharmacists in the hospital? Let me show another piece. It's not just only the Stephen Jensen case drop. It's the total, this one also drop. But anyway, I just see the proportion of the Stephen Jensen and 10 case is the same proportion as during we conduct the study from 2010 to 2012. It's about 1.6 to 1.7. It's still the same. And I think it's not just only the testing at the hospital. It's a policy that the pharmacists have to redo the Stephen Jensen case as much as they can. So whenever the doctor prescribe the drug that can induce the Stephen Jensen, they will give the counseling to the patient. How can the podium of the Stephen Jensen and ask the patient come as fast as they can to stop the drug? So I think this might be one of the factors that decrease the case. And the other one might be the testing. So I think we have to conduct the research to find out what is the real factor. So in Thailand it's quite interesting that in provinces, pharmacists are more powerful than clinicians. They have more say in Stephen Jensen how to prescribe the medication. But in Bangkok, doctors have a final say, not the pharmacists. Somehow that is debatable. We could find out the way. But anyhow, somehow the Stephen Jensen is dropping. Because for the drug safety, it's like the pharmacist's role to reduce the risk of the drug.