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biosensors Biosensors Biosensors Biosensors 2079-6374 MDPI 10.3390/bios2020171 biosensors-02-00171 Article Developing a Real Time Sensing System to Monitor Bacteria in Wound Dressings Farrow Malcolm J. 1 Hunter Iain S. 2 Connolly Patricia 1 * Department of Bioengineering, University of Strathclyde, Wolfson Centre, Glasgow, G4 0NW, UK; E-Mail: Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, G1 1XW, UK; E-Mail: Author to whom correspondence should be addressed; E-Mail: 09 05 2012 06 2012 2 2 171 188 20 03 2012 20 04 2012 25 04 2012 © 2012 by the authors; licensee MDPI, Basel, Switzerland. 2012

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (

Infection control is a key aspect of wound management strategies. Infection results in chemical imbalances and inflammation in the wound and may lead to prolonged healing times and degradation of the wound surface. Frequent changing of wound dressings may result in damage to healing tissues and an increased risk of infection. This paper presents the first results from a monitoring system that is being developed to detect presence and growth of bacteria in real time. It is based on impedance sensors that could be placed at the wound-dressing interface and potentially monitor bacterial growth in real time. As wounds can produce large volumes of exudate, the initial system reported here was developed to test for the presence of bacteria in suspension. Impedance was measured using disposable silver-silver chloride electrodes. The bacteria Staphylococcus aureus were chosen for the study as a species commonly isolated from wounds. The growth of bacteria was confirmed by plate counting methods and the impedance data were analysed for discernible differences in the impedance profiles to distinguish the absence and/or presence of bacteria. The main findings were that the impedance profiles obtained by silver-silver chloride sensors in bacterial suspensions could detect the presence of high cell densities. However, the presence of the silver-silver chloride electrodes tended to inhibit the growth of bacteria. These results indicate that there is potential to create a real time infection monitor for wounds based upon impedance sensing.

electrical impedance infection sensor Staphylococcus aureus wound
1. Introduction

Wounds in the skin provide an ideal environment for bacteria to inhabit and colonise the wound [1]. This may lead to an established infection where the human immune system struggles to reduce the numbers of bacteria. Suspected wound infections require sampling of tissue and fluid, which is an invasive procedure in that it requires disturbing the dressing to swab the areas and exudate suspected of harbouring infection. Infection diagnostic systems used in hospital laboratories comprise mainly culture methods [2] and these are slow, costly and labour intensive [3]. This may delay the selection of an appropriate wound healing regime and increase the time before focused treatment can be started. Wound management would be greatly advanced if the presence of infection could be monitored in real time without disturbing the dressing.

Frequency of dressing changes varies from country to country, in some community settings dressings are changed daily but advanced wound dressings should only require changing every three to seven days unless wound exudate is particularly heavy. Thus there is opportunity for infection monitoring systems that do not require removal of the dressing.

The electrical impedance of tissues has been studied in a range of applications which include excised tissues, diagnosis of cancer, nutritional assessment, and muscle and lung functionality [4,5]. During the 1970s and 1980s bacterial growth monitored by electrical impedance methods was studied extensively due to the prospect of automation [6,7,8,9,10,11]. More recently, research has concentrated on micro and nano devices to create possible point of care diagnostic devices [12]. However these would still require dressing changes or sampling of wound exudate. Studies that have combined electrical impedance and sensors, and that can be used without removing the dressing include a system to monitor the size of chronic wounds [13], and a product to monitor wound moisture levels [14,15].

Electrical impedance can be represented in the form of its magnitude (|Z|) and phase angle (θ), or in complex notation with resistance (Z') and reactance (Z"). These are related by Equations (1) and (2).

To examine the relative changes from the initial readings over time, the impedance measurements can be normalised. The normalised impedance modulus (|Z|n) at each frequency point is calculated by dividing the hourly reading (|Z|hour) by the reading at zero hours (|Z|time = 0), as shown in Equation (3).

Thus |Z|n = 1 for all frequencies at time zero and deviations from this with time can be seen clearly on a graphical plot of |Z|n against frequency. Similarly the normalised phase angle (Equation (4)), resistance and reactance can be calculated.

The normalised impedance data are analysed by comparing the normalised impedance profile plots (either normalised impedance modulus, or normalised phase angle, or both) against frequency in order to look for discernible differences caused by the presence of cells that were not present on the control plots. One feature of particular interest that emerges is the frequency band or location of any peaks in such graphs that occurred in the normalised impedance profiles over frequency. Normalised impedance data shows that different cell types demonstrate different characteristic responses from day to day in the growth cycle, that were consistent from culture to culture, with different locations of peaks in Zn with respect to frequency. Such consistent characteristic responses meant that cells could be typed in culture according to their normalised impedance profile across the frequency spectrum and that this might be extended to bacteria [16]. Impedance normalisation has also been used to monitor cell mobility, adhesion and alterations [17,18,19,20].

The aim of the current study was to investigate the feasibility of creating an infection monitor for wounds by combining the normalised impedance profile method with the moisture sensors previously described by McColl et al. [15]. The hypothesis was that these might have the potential to provide unique signature traces to indicate the presence of bacteria and differentiate species of bacteria. Wounds can produce significant quantities of fluid, with a moderately exuding wound producing 0.5 mL per square centimetre in a 24 h period [21]. This provides a suitable environment for bacteria to grow in the wound fluid and creates problems with exudate management in wound dressings. In addition the bacteria can attach and create biofilms on tissue components within the wound [22,23]. Therefore it is important to study bacterial suspensions and formation of biofilms on the electrode surfaces as part of the representation of possible scenarios in wounds. This paper describes the impedance profiles of bacterial growth in suspensions using screen-printed electrodes and several strains of Staphylococcus aureus, a species commonly isolated from wounds [3]. The results of the biofilm study will be detailed in a future companion paper.

2. Materials and Methods

The key experiments performed were to:

Investigate the effects on impedance profiles against frequency with the sensor system for: Staphylococcus aureus growth in suspension, both in a standard culture broth, and when boosted by the addition of glucose to the same broth.

Investigate the effects of: (a) lower inoculation density on the impedance profiles and (b) the effect of glucose concentration on the impedance profiles. These experiments were performed to explore the detection limits and understand the differences caused by the presence of glucose seen in the initial experiments.

Test the changes in growth inhibition that might have been caused by the presence of the silver-silver chloride (Ag-AgCl) sensors by prewashing of the sensors to remove early release of silver chloride deposits

Investigate the effect of different cell inoculation densities on the bacterial growth of three strains of Staphylococcus aureus in the presence of Ag-AgCl sensors.

Investigate the effect of the application of voltage during the impedance measurements on the bacterial growth of three strains of Staphylococcus aureus. This was to further investigate the inhibiting effect seen in previous experiments, as previous results indicated that by performing the impedance measurements growth inhibition was increased.

The conditions and methods for each of the experiments are given below.

2.1. Bacteria

The bacteria used in the experiments were Staphylococcus aureus: one laboratory strain RN4220, and two clinical isolates SA081, and SA082 donated by the Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde. All three strains were stored in 80% (v/v) glycerol at −80 °C. For use, the strains were streaked onto Mueller-Hinton agar (38 g/L) (Oxoid, Cambridge, UK) and incubated for 24 h before experiments. A single colony was grown in Mueller-Hinton broth (MHB) for 24 h and serially diluted to provide the inoculation density for each of the suspension experiments.

2.2. Sensors

The disposable silver-silver chloride (Ag-AgCl) sensors were identical to those created for a clinical trial monitoring moisture levels underneath wound dressings [15] and made available for the project by Ohmedics Ltd. ( The sensors were manufactured by screen printing a silver chloride ink onto a flexible polyethylene substrate. Each sensor had two planar electrodes with 3 mm diameter tips, 10 cm track lengths and connection pads (Figure 1(a)). The tracks were insulated with an adhesive layer of the polyethylene. Before the experiments, the sensors were sterilised in 70% (v/v) ethanol for 10 min and rinsed three times in sterile water [24,25].

2.3. Key Experiments 2.3.1. Growth of Strain RN4220

The test rig consisted of one impedance culture vial with a sensor inside and one control culture vial with no sensor. The impedance vial consisted of a 20 mL universal vial (Greiner Bio-One, Stonehouse, UK) and a specially designed PTFE cap which held the screen-printed Ag-AgCl sensor suspended in the centre of the vial (Figure 1(b)). The control vial was a standard 20 mL universal vial. Both vials were filled with 5 mL of MHB. Both vials were held with a clamp stand on an orbital shaker 240 rpm (IKA, Staufen, Germany), inside an incubator, 37 °C (LEEC, Nottingham, UK). The sensor was connected via crocodile clips and BNC cables to a Solartron 1260 frequency response analyser (Solartron, Hampshire, UK). Impedance measurements involved frequency sweeps from 1 MHz to 0.1 Hz at an RMS voltage of 200 mV.

(a) The basic design of the screen-printed sensors. (b) The bacterial suspension test vial comprised a 30 mL universal vial, 5 mL of media, a specifically designed polytetrafluoroethylene (PTFE) cap and a Ag-AgCl sensor. (c) The test rig to allow parallel measurement of up to eight bacterial suspension test vials.

Two initial impedance measurements were performed on the impedance vial before bacterial inoculation to read the background impedance, and then measurements performed once every hour for 17 h. Both vials were inoculated with a single colony of RN4220, approximately 1 × 106 CFU∙mL−1, after the background impedance readings were taken. The final numbers of bacteria were calculated by colony counts. For the control vial no inoculation was performed. The control vial impedance readings were taken in order to record any conditioning effects of the MHB on the electrode impedance, and to observe such changes when no bacteria were present. The complete protocol was repeated over five independent experiments on this strain.

To examine whether the culture media affected the impedance measurements, the RN4220 growth procedure described above was repeated with the MHB media but with added glucose. In this case each vial contained 4.9 mL of MHB and 0.1 mL of 10% glucose (w/v) to create a 0.2% (v/v) glucose concentration. Five replicate experiments were also performed.

2.3.2. Lower Inoculation Densities, Glucose and Pre-washing

To allow hourly impedance measurements to be performed on up to eight bacterial suspensions in parallel, a modified test rig was created (Figure 1(c)). The test vials were held in a specially designed PTFE rack on the orbital shaker. The sensors were connected to the 1260 frequency analyser via a Solatron 1281 multiplexor (Solartron, Hampshire, UK). Test vials were filled with 4.9 mL of media and inoculated with 100 μL of RN4220 culture containing approximately 1 × 103 CFU∙mL−1, diluted from a 24 h MHB culture. Control vials containing bacteria and no sensors were used in parallel for each of the parameter variations.

The first parallel suspension experiment investigated: (a) the effect of lower inoculation density on the impedance profiles; (b) the effect of glucose concentration on the impedance profiles; and (c) whether pre-washing the sensors improved bacterial growth. The pre-washed sensors were washed for 24 h in MHB with the media refreshed three times prior to the start of the impedance measurements. The eight vials were: (1) MHB; (2) MHB, RN4220; (3) MHB-0.2% glucose; (4) MHB-0.1% glucose, RN4220; (5) MHB-0.2% glucose, RN4220; (6) MHB-0.4% glucose, RN4220; (7) MHB, with pre-washed sensor; (8) MHB, with pre-washed sensor, RN4220. Hourly impedance measurements were performed on all eight vials for 16 hours and the complete protocol repeated three times.

2.3.3. Presence of Ag-AgCl Sensors

To investigate bacterial growth simply in the presence of silver from the Ag-AgCl sensors (without any application of voltage for impedance measurements) the bacteria were grown from four different starting cell densities for 24 h in systems in which the sensors were present but no impedance measurements were made. Two 20mL universal vials were filled with 4.9 mL of (MHB) to create a test and control vial. A sensor was placed in the test vial and both vials inoculated with 100 μL of media containing approximately 1 × 105 CFU∙mL−1, diluted from a 24 h broth culture. An additional three pairs of test and control vials (no sensors present) were also tested with starting cell densities of 1 × 104, 1 × 103 and 1 × 102 CFU∙mL−1. Cultures were grown at 37 °C for 24 h on an orbital shaker (240 rpm). The final numbers of bacteria were calculated using colony counts. The complete procedure was replicated three times for each of the strains RN4220, SA081 and SA082.

2.3.4. Presence of Impedance Measurements

The second parallel suspension experiment investigated the influence of the application of voltage during the hourly impedance measurements on bacterial growth. Eight test vials were paired into four sets. All had sensors placed inside. Each pair of vials was inoculated from separate 24 h cultures and impedance measurements were only performed on one vial from each pair every hour for 24 h. This was repeated for each strain of Staphylococcus aureus: RN4220, SA081 and SA082. In addition, hourly impedance measurements were performed on four additional control test vials containing only MHB in order to track any conditioning effect of the impedance measurements on electrodes in the broth.

3. Results 3.1. RN4220 Growth

At the end of the experiments (17 h) the RN4220 vials containing sensors had reached cell densities of approximately 1 × 109 CFU∙mL−1, which matched the RN4220 control vials. This indicates that, from an inoculation density of 1 × 106 CFU∙mL−1, the sensors probably had no effect on bacterial growth. The normalised magnitude, phase angle, resistance and reactance readings, as discussed in Section 1, were examined for differences between the RN4220 cultures and the control cultures without bacteria.

Examples of the normalised phase angle profiles from the single suspension experiments: (a) Control, MHB-only; (b) RN4220 culture 1; (c) RN4220 culture 2. Dotted line indicates the normalized phase angle peak.

The normalised profiles showed some clear trends and differences between the control vial and the vial with bacterial suspension. The most significant difference in the normalised magnitude was that in the MHB-only vials the value of the reading between 0.1 and 1 Hz decreased to a value of 0.5 while the RN4220 culture vials decreased to values of 0.4 and 0.3. However the discernible differences were more pronounced in the normalised phase angle. In the control (MHB-only), a peak in the normalised phase angle occurred between 50 and 100 Hz at the start and decreased over time to between 0.79 and 2.00 Hz at 17 h (Figure 2(a)). The normalised phase angle peak of the control (MHB-only) descended below 10 Hz between 4 and 10 h across all five separate samples. In contrast, in the RN4220 cultures, the normalised phase peak after 10 h remained between 32 and 20 Hz and hence never descended below 10 Hz (Figure 2(b)). This was repeatable over 5 separate culture experiments. Therefore it appears that the two cultures do have separate signature traces in the phase angle over frequency and is the first indication that peaks in signature traces of phase angles in normalised impedance plots could distinguish between the absence and/or growth of bacteria. In three of the five RN4220 cultures, a secondary peak appeared at a frequency less than 10 Hz and reached a higher magnitude by 17 h than the primary peak (Figure 2(c)). However the primary peak was still visible and allows the RN4220 cultures to be distinguished from the MHB-only samples by comparison of the normalised phase angle plots.

Examples of the normalised magnitude profiles from the single suspension experiments: (a) Control, MHB and 0.2% glucose; (b) RN4220 in MHB and 0.2% glucose. Arrows indicate peaks of interest.

There were similar discernible differences in the normalised phase peak between the MHB with glucose and the RN4220 culture in MHB with glucose. The normalised phase peak at 17 h was between 1 and 2 Hz in all five media-only cultures, and between 10 and 32 Hz for the RN4220-glucose cultures. In addition to the differences in the normalised phase peaks the normalised magnitude peaks showed clear differences with the added glucose. In the MHB-glucose-only vials by 17 h a first peak had occurred between 1 and 3 Hz and a second one between 200 and 1.3 kHz (Figure 3(a)). In contrast, in the RN4220-glucose experiments the first and second peaks were not present at the end of the experiment, however a third peak between 2.5 k and 6.3 kHz was present, as shown in Figure 3(b). The change in the peaks shown in the RN4220 cultures occurred between 4 and 8 h after inoculation. This was repeatable over five separate culture experiments and is the first evidence that discernible differences in the normalised phase angle profiles occur due to the presence of bacteria, depending on the media contents.

3.2. Lower Inoculation Densities, Glucose and Pre-washing

The final cell densities of RN4220 after 16 h culture with Ag-AgCl sensors in MHB, MHB with glucose and with pre-washed sensors, showed wide variation, as shown in Figure 4. The control cultures, which contained no sensors, always reached approximately 1 × 109 CFU∙mL−1 within 24 h. Only one of the three vials with sensors in MHB grew to a density in excess of 5 × 107 CFU∙mL−1. In the experiments with added glucose and sensors present, one MHB-0.1% glucose, three MHB-0.2% glucose and one MHB-0.4% glucose vials grew to more than 5 × 107 CFU∙mL−1. For the sensors that were pre-washed before inoculation, only two of the three vials reached densities above 5 × 107 CFU∙mL−1. In total there were 15 RN4220 vials with sensors, and of these 15 it was observed that 8 reached cell densities above 5 × 107 CFU∙mL−1, and the remaining 7 remained below this level. This was evidence that the presence of the Ag-AgCl sensors may have inhibited the RN4220 growth from lower inoculation densities. The level of glucose appears to affect the amount of inhibition, with 0.2% being the optimum to overcome the reduced growth.

The final cell numbers of RN4220 in the parallel suspension experiment from low starting cell densities. Bar colours indicate sample number: Red—sample one; Blue—sample two; and Yellow—sample three.

An example of the normalised profiles with Ag-AgCl sensors in parallel suspensions: (a) MHB; (b) MHB and low density RN4220 at 16 h; (c) MHB and high density RN4220 at 16 h. Dotted lines indicates the normalised phase angle peak at 16 h.

The normalised phase angle profiles of the lower inoculation density experiments again showed the clearest differences between bacterial cultures and MHB–only vials with sensors present in both to record impedance. In all 24 vials, irrespective of the media type or preparation of the sensor, there were three types of normalised phase angle profiles. The profile for the controls, the MHB-only, contained a peak that increased in magnitude over time and at 16 hours was between 0.79 and 1.58 Hz (Figure 5(a)). These peaks were caused by a reduction in the resistance and capacitance from the background reading. There were two contrasting normalised phase angle profiles for the vials inoculated with low density RN4220 depending on the final cell density reached. The profiles of the low final cell density vials (<1 × 107 CFU∙mL−1) were very similar to the media-only profiles, with magnitudes of the peak above 1.26 and frequencies between 0.79 and 1.58 Hz, and the difference between them could not be distinguished (Figure 5(b)). These profiles occurred in all of the inoculated vials and the final cell numbers were found to be less than 5 × 107 CFU∙mL−1. The second RN4220 phase profile (Figure 5(c)) occurred in vials inoculated with low starting density RN4220 but in these the final cell densities were between 1 × 108 and 1 × 109 CFU∙mL−1. The magnitudes of the peak were below 1.26 and the frequencies of the peaks between 1.58 and 2.00 Hz. This change in the peak was caused by a larger decrease in the resistance and an increase in the capacitance, potentially indicating the increase in metabolites and cell membranes respectively. Therefore it appears that once bacterial cultures reach a sufficient cell density a separate signature trace in the normalised phase angle over frequency occurs and indicates that comparing signature traces could discern between the absence and or/growth of bacteria above certain densities.

Examination of the magnitude and frequency of the normalised phase angle peak at 16 h shows a distinction in magnitude between the RN4220 cultures that reached above 5 × 107 CFU∙mL−1 and those that did not. However the frequency of the peak is not completely distinct due to overlapping frequency ranges at approximately 1.58 Hz (Figure 6). This has obvious implications for a detection system that uses frequency bands to discern the absence or presence of bacteria.

The magnitude and frequency of the normalised phase angle peak from all 24 vials from the parallel suspension experiments. The majority of the vials with cell densities that reached above 1 × 107 CFU∙mL−1 occurred in the lower right quadrant, while the media only and lower density vials occurred in the upper left quadrant.

3.3. Presence of Ag-AgCl Sensors

To investigate the effect of the inoculation density on the bacterial growth in the presence of Ag-AgCl sensors, the presence of which will introduce some silver ions into the culture system, the three strains of Staphylococcus aureus were grown from four starting cell densities between 1 × 102 and 1 × 105 CFU∙mL−1 without the application of voltage for impedance measurements (Figure 7). This would also show whether the clinical strains were more robust in the presence of the AgCl than RN4220. The final cell densities with sensors indicated that, below a critical starting cell density, it was not guaranteed that the final cell densities would reach 1 × 109 CFU∙mL−1 (expected level based on the RN4220 controls without sensors). For RN4220, this critical starting density was approximately 1,000 CFU∙mL−1 while, for SA081 and SA082, the density was approximately 1 × 105 CFU∙mL−1. This provides further evidence that the presence of the Ag-AgCl sensors has an influence on bacterial growth rates and that the two clinical strains may not be as resistant to AgCl as the RN4220 strain.

The final numbers of RN4220, SA081 and SA082 with Ag-AgCl sensors after 24 h culturing from different starting densities. Three replicate cultures are shown for each of the three strains of Staphylococcus aureus at each starting density. Sample 1(); Sample 2(); Sample 3(); Mean control ().

3.4. Influence of Impedance Measurement

The final experiment investigated the influence of applying voltage to the electrodes, with impedance measurements and Ag-AgCl sensors, on the bacterial growth of the three Staphylococcus aureus strains. The controls of all three strains, which contained no sensors, always reached approximately 1 × 109 CFU∙mL−1 within 24 h. The strain RN4220 reached control levels without impedance measurements. However the 4 separate vials with impedance measurements had final cell densities between 2 × 103 and 6 × 103 CFU∙mL−1 (Figure 8(a)). In the vials without impedance measurements, the strain SA081 reached 1 × 108 CFU∙mL−1 in three vials and only 1 × 106 CFU∙mL−1 in the fourth. With impedance measurements the SA081 strain reached cell densities between 1 × 103 and 1 × 106 CFU∙mL−1. The strain SA082 without impedance measurements reached control densities in two vials and only 1 × 104 CFU∙mL−1 in the other two. Similarly, the strain SA082 had two vials reaching 1 × 108 CFU∙mL−1 and two vials reaching 3 × 104 CFU∙mL−1 with impedance measurements. These results suggest that performing impedance measurements every hour may have an influence on the bacterial growth. These final cell densities clearly show that the presence of the Ag-AgCl electrodes inhibits normal growth rates and that the application of electrical voltage during the impedance measurements increases this reduction.

The normalised phase angle profiles from the influence of impedance measurement experiments were expected to be similar to those detailed in Section 3.2. The frequency of the normalised phase angle peak occurred in all 4 control and 12 bacterial cultures between 0.8 and 2 Hz with no discernible differences between the controls and bacterial cultures. However the differences in magnitude changes of the peaks as seen in the parallel suspension experiments were observed (Figure 8(b)). The normalised phase angle peaks of the 4 media-only and 10 low density vials of RN4220, SA081 and SA082 started at approximately 8 h and increased over time to magnitudes above a value of 1.5. In contrast the peaks of the two high density SA082 vials increased until 13 to 14 h and then decreased for the remaining hours. Despite the low number of samples displaying high cell densities it appears that the examination of normalised phase profiles of multiple strains of Staphylococcus aureus shows a difference in the signature trace when growth is in excess of 5 × 107 CFU∙mL−1 compared with low density cultures (<1 × 106 CFU∙mL−1) or media only. This is the first evidence that the phase signature traces over frequency can be used to discern high growth levels in multiple strains of Staphylococcus aureus.

(a) The final cell numbers of RN4220, SA081 and SA082 with Ag-AgCl sensors after 24 h with and without the application of impedance measurements. Four replicate cultures are shown for each of the three strains of Staphylococcus aureus. () Start value; () Final cell density without impedance measurements; () Control growth with no sensors; () Final cell density with impedance measurements. (b) Typical magnitudes of the normalised phase angle peak over time from the influence of impedance measurement experiments. The peak occurs at approximately 8 h and increases over time unless the bacteria reach cell densities in excess of 1×107 CFU∙mL−1 where upon it starts to decrease.

4. Discussion 4.1. Detection of Bacteria

The normalised impedance profiles over frequency have shown a novel way of detecting the presence and/or absence of bacteria in real time. The analysis of the profiles for unique signature traces will indicate the presence of Staphylococcus aureus strains in excess of 5 × 107 CFU∙mL−1, which is in accordance with the detection limits of earlier studies of bacteria growth with impedance [8]. These earlier studies on bacteria in bulk fluids, Ur and Brown [11], Cady [6], Richards et al. [10], and Firstenberg-Eden and Eden [7], for example, concentrated on specific frequencies and produced characteristics curves over time for different species of bacteria. Firstenberg-Eden and Eden [7] also produced a mathematical model for calculating the starting cell density. The limitations of these systems were that they required controlled conditions to reproduce the curves and parameters known about the bacteria to calculate the cell densities. The advantage of the normalised impedance profiles over frequency is that once the signature traces are known the controls are not required. This may be ideal for monitoring wounds for infection in real time when a control would not be possible.

The mechanisms that have the potential to cause differences in the normalised impedance of biological systems within the frequency range examined are counterion diffusion effects and capacitive charging of cell membranes. At low frequencies (between 10 Hz and a few kilohertz) the impedance is characterised by counterion diffusion effects while the capacitive charging of cell membranes occurs in the tens of kilohertz to tenths of a megahertz range [5]. The counterion diffusion effect is caused by the cell membranes acting as large capacitors and the current flowing only through the extracellular media. The impedance within the capacitive membrane charging frequency range is governed by cell membrane reactance. As the frequency increases the membrane is not fully charged therefore decreasing the reactance. In addition this allows more current to flow inside the cell and hence the resistance decreases.

The relative changes over time observed in the normalised phase profiles with MHB-only may be due to oxidation of the electrode surface or absorption of molecules onto the electrode surfaces. In the RN4220 cultures, the presence of the cells produced further changes observed in the normalised phase profiles. One explanation for these additional changes is that they are due to the metabolism of nutrient molecules to smaller and more conductive ones. An increase in conductivity of bacterial cultures was previously explained by changes to smaller and more highly charged molecules in the media [7]. Another possibility is that this may be linked to the increased number of suspended cells and their membranes. Finally, although there may be some bacterial attachment to the electrodes the major influence on the impedance in this experimental arrangement is the growth of the organisms in the bulk broth. Of course, as the technique is transferred to wound dressings then attachment to the electrodes may become a much more important influence.

The contents of the media can influence the impedance profiles, as observed in the single suspension experiments when 0.2% glucose was added to the MHB. In comparison to the experiments without glucose, there were noticeable differences in the normalised impedance magnitude profiles between the controls and the bacterial cultures. The profile for the RN4220 cultures with 0.2% glucose showed an additional magnitude peak between 2.5 k and 6.3 kHz. This additional peak may have been caused by a change in the structure of the cell walls since it has been shown that the available nutrients, including carbon have an influence on the structure and composition of Staphylococcus aureus cell walls [26]. Another possibility is an additional metabolic product is produced when glucose is present, for example, bacteria metabolise glucose to lactic acid and then to carbonic acid [7]. This would alter the media composition and the interaction between the cells and media could have caused an additional peak in the normalised magnitude.

There were an increased number of cell replications from the lower starting cell density in the parallel experiments. The glucose would have been used for energy and basic cell construction rather than modified cell structures. This may be the reason why the additional magnitude peak was not observed in the parallel experiments with glucose. In the intended application of monitoring wounds, the availability of nutrients may be restricted in the host [27] and therefore the signature traces as a result of the bacteria-glucose interaction may also not occur.

Another consideration is whether in an actual wound detecting 5 × 107 CFU∙mL−1 would be adequate or actually be a late warning system given that infections are more likely to occur at cell densities greater than 1 × 105 CFU per gram of tissue [3]. Correlations between swab cultures and tissue biopsies have been shown, for example, 1 × 105 CFU per gram of tissue is equivalent to approximately 5.9 × 105 CFU per swab of a square centimetre [28]. However, it is still unclear how bacteria levels per tissue gram or per cm2 would relate to a detection system that indicates 5 × 107 CFU mL−1. The levels of bacteria in a wound must be evaluated with other important factors, including bacterial virulence and host resistance [29]. Therefore valuable information given by an infection monitoring system for wounds could be used to indicate, like semi-quantitative swabs, the growth between light (1+) and profuse (4+) cultures [3]. This would provide information to the healthcare personnel that could be used in addition to other factors to select the most appropriate treatment options.

4.2. Bacterial Growth

The bacterial growth experiments from different densities suggest that below a critical cell density the Ag-AgCl sensors are slowing or inhibiting growth. The probable cause is silver ions, which are known to inhibit bacterial growth by cell membrane damage and damage to associated proteins [30,31]. Alternatively silver salts have been shown to enhance or diminish the mechanism of silver inhibition depending on the concentration of the anions [32,33]. Therefore there may have been differences in precipitation of AgCl between individual samples.

The range of cell densities observed in the experiments described in Section 3.2 may have been affected by the media contents, sensor preparation and presence of impedance measurements. In all three experimental runs the RN4220 culture with 0.2% glucose added to the MHB reached the levels of control which could be related to a glucose concentration for an optimum growth rate. The pre-washed sensors reached the control levels in two of the three experimental runs possibly indicating that pre-washing of the sensors is a solution to the problem of inhibition. The one pre-washed sensor vial that did not achieve the control levels of growth may have been poorly washed.

The possibility of the impedance measurements having a detrimental effect on the bacterial growth was confirmed in the influence of impedance measurement experiments on all three Staphylococcus aureus strains. This possibly indicates that the measurements were causing more silver to be released into the media or that the electric current was damaging the culture. This is surprising since the total current density for the short time of measurement was in the range of 50 A∙m−2 at a voltage of 200 mV rms. Inhibition of bacteria by electrical stimulation generally uses constant currents or high voltage pulsed currents for prolonged periods, hours or days, for example [34]. Also an alternating current did not inhibit Escherichia coli compared with a direct current [35]. Therefore it would seem unlikely that an alternating current that is applied for approximately 2 min every hour directly causes the inhibition.

It is worth mentioning that a chronic wound in vivo is a complex environment with many additional factors potentially effecting the normalised impedance measurements, for example the dressing material, moisture levels, and the differences between colonisation, active infection and biofilm growth. Dressing materials that release silver or iodine will affect the measurements in a similar manner to the silver being released from the Ag-AgCl electrodes and therefore the bacteria are likely to still produce a noticeable change in the normalised impedance. Moisture levels are unlikely to be an issue with an active infection because infected wounds tend to produce more exudate than colonized wounds. The effect of biofilms on normalised impedance profiles has been investigated in a companion study.

5. Conclusion

This paper has shown that, by using electrical impedance with screen-printed disposable Ag-AgCl sensors in bacterial cultures and analysing the normalised impedance profiles over the frequency spectrum, the presence and/or absence of bacteria can be monitored in real time. Clearly the results obtained relate only to Staphylococcus aureus and work is now required to look at other types of bacteria and multiple organism cultures to check for the relevant impedance signatures. If signatures for other types of bacteria can be clearly identified then this novel system would be ideal to monitor infection underneath dressings, allowing healthcare personnel to make more informed decisions about changing dressings and administrating the best treatment. Recently, the presence of biofilms in wounds has been highlighted as one of the causes of delayed wound healing. Therefore, examining the impedance signature traces over frequency with biofilm growth on the disposable electrodes will also be a part of future work. The concept described here is the subject of a patent application by the Univerity of Strathclyde [16].

Malcolm Farrow was the recipient of a doctoral studentship funded by the EPSRC.

References Kingsley A. A proactive approach to wound infection Nurs. Stand. 2001 15 50 58 12216211 Costerton J.W. Post J.C. Ehrlich G.D. Hu F.Z. Kreft R. Nistico L. Kathju S. Stoodley P. Hall-Stoodley L. Maale G. James G. Stoereanos N. DeMeo P. New methods for the detection of orthopedic and other biofilm infections FEMS Immunol. Med. Microbiol. 2011 61 133 140 10.1111/j.1574-695X.2010.00766.x21204998 Bowler P.G. Duerden B.I. Armstrong D.G. Wound microbiology and associated approaches to wound management Clin. Microbiol. Rev. 2001 14 244 269 10.1128/CMR.14.2.244-269.200111292638 Rutkove S.B. Electrical impedance myography: Background, current state, and future directions Muscle Nerve 2009 40 936 946 10.1002/mus.21362 Rigaud B. Morucci J.P. Chauveau N. Bioelectrical impedance techniques in medicine. 1. Bioimpedance measurement—Second section: Impedance spectrometry Crit. Rev. Biomed. Eng. 1996 24 257 351 9196884 Cady P. Rapid automated bacterial identification by impedance measurement New Approaches to the Identification of Microorganisms Heden C. Illeni T. Wiley New York, NY, USA 1975 73 99 Firstenberg-Eden G. Eden G. Impedance Microbiology Wiley New York, NY, USA 1984 Eden G. Eden R. Enumeration of microorganisms by their dynamic AC conductance patterns IEEE Trans. Biomed. Eng. 1984 31 193 198 10.1109/TBME.1984.3254066368364 Kell D.B. Davey C.L. Conductimetric and impedimetric devices Biosensors: A Practical Approach Cass A.E. Oxford University Press Oxford, UK 1990 125 154 Richards J.C.S. Jason A.C. Hobbs G. Gibson D.M. Christie R.H. Electronic measurement of bacterial-growth J. Phys. E 1978 11 560 568 10.1088/0022-3735/11/6/017355620 Ur A. Brown D.F.J. Monitoring of bacterial activity by impedance measurements New Approaches to the Identification of Microorganisms Heden C. Illeni T. Wiley New York, NY, USA 1975 63 71 Lazcka O. Del Campo F.J. Munoz F.X. Pathogen detection: A perspective of traditional methods and biosensors Biosens. Bioelectron. 2007 22 1205 1217 10.1016/j.bios.2006.06.03616934970 Weber S.A. Watermann N. Jossinet J. Byrne J.A. Chantrey J. Alam S. So K. Bush J.O. Kane S. McAdams E.T. Remote wound monitoring of chronic ulcers IEEE Trans. Inf. Technol. Biomed. 2010 14 371 377 10.1109/TITB.2010.204260520659833 McColl D. Cartlidge B. Connolly P. Real time monitoring of moisture levels in wound dressings in vitro: An experimental study Int. J. Surg. 2007 5 316 322 10.1016/j.ijsu.2007.02.008 McColl D. MacDougall M. Watret L. Connolly P. Monitoring moisture without disturbing the wound dressing Wounds UK 2009 5 94 99 Shedden L. Connolly P. A System and Method for Cell Characterisation Patent Application WO/2009/136157 May 2009 Lind R. Connolly P. Wilkinson C.D.W. Breckenridge L.J. Dow J.A.T. Single cell mobility and adhesion monitoring using extracellular electrodes Biosens. Bioelectron. 1991 6 359 367 10.1016/0956-5663(91)85023-P Giaever I. Keese C.R. Micromotion of mammalian-cells measured electrically Proc. Natl. Acad. Sci. USA 1991 88 7896 7900 10.1073/pnas.88.17.78961881923 Rothermel A. Nieber M. Mueller J. Wolf P. Schmidt M. Robitzki A. Real time measurement of PMA-induced cellular alterations by microelectrode array-based impedance spectroscopy BioTechniques 2006 41 445 450 10.2144/00011225417068960 Whulanza Y. Ucciferri N. Domenici C. Vozzi G. Ahluwalia A. Sensing scaffolds to monitor cellular activity using impedance measurements Biosens. Bioelectron. 2011 26 3303 3308 10.1016/j.bios.2011.01.00221256732 Thomas S. Fear M. Humphreys J. Disley L. Waring M. The effect of dressing on the production of exudate from venous leg ulcers Wounds 1996 8 145 150 James G.A. Swogger E. Wolcott R. Pulcini E.D. Secor P. Sestrich J. Costerton J.W. Stewart P.S. Biofilms in chronic wounds Wound Repair Regen. 2008 16 37 44 10.1111/j.1524-475X.2007.00321.x18086294 Schierle C.F. de la Garza M. Mustoe T.A. Galiano R.D. Staphylococcal biofilms impair wound healing by delaying reepithelialization in a murine cutaneous wound model Wound Repair Regen. 2009 17 354 359 10.1111/j.1524-475X.2009.00489.x19660043 Smith K. Hunter I.S. Efficacy of common hospital blocides with biofilms of multi-drug resistant clinical isolates J. Med. Microbiol. 2008 57 966 973 10.1099/jmm.0.47668-018628497 Sopwith W. Hart T. Garner P. Preventing infection from useable medical equipement: A systematic review BMC Infect. Dis. 2002 2 1 10 10.1186/1471-2334-2-111835694 Dobson C.B. Archibald A.R. Effect of specific growth limitations on cell wall composition of Staphylococcus aureus H Arch. Microbiol. 1978 119 295 301 10.1007/BF00405409736712 Brown M.R.W. Williams P. The influence of environment on envelope properties affecting survival of bacteria in infections Annu. Rev. Microbiol. 1985 39 527 556 10.1146/annurev.mi.39.100185.0025233904611 Levine N.S. Lindberg R.B. Mason A.D. Pruitt B.A. The quantitative swab culture and smear: A quick, simple method for determining the number of viable aerobic bacteria on open wounds J. Trauma 1976 16 89 94 10.1097/00005373-197602000-000021255833 Schultz G.S. Sibbald R.G. Falanga V. Ayello E.A. Dowsett C. Harding K. Romanelli M. Stacey M.C. Teot L. Vanscheidt W. Wound bed preparation: A systematic approach to wound management Wound Repair Regen. 2003 11 1 28 10.1046/j.1524-475X.2003.11101.x12581419 Clement J.L. Jarrett P.S. Antibacterial silver Met. Based Drugs 1994 1 467 482 10.1155/MBD.1994.46718476264 Percival S.L. Bowler P.G. Russell D. Bacterial resistance to silver in wound care J. Hosp. Infect. 2005 60 1 7 10.1016/j.jhin.2004.11.01415823649 Gupta A. Maynes M. Silver S. Effects of halides on plasmid-mediated silver resistance in Escherichia coli Appl. Environ. Microbiol. 1998 64 5042 5045 9835606 Silver S. Bacterial silver resistance: Molecular biology and uses and misuses of silver compounds FEMS Microbiol. Rev. 2003 27 341 353 10.1016/S0168-6445(03)00047-012829274 Kloth L.C. Electrical stimulation for wound healing: A review of evidence from in vitro studies, animal experiments, and clinical trials Int. J. Low. Extrem. Wounds 2005 4 23 44 10.1177/1534734605275733 Rowley B.A. Electrical current effects on Escherichia-coli growth-rates Exp. Biol. Med. 1972 139 929 934 10.3181/00379727-139-36269

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House committee lifts ban on Common Core

The state House passed a resolution Thursday to lift the ban on implementing the Common Core State Standards, allowing the standards to go forward pending final approval from the Senate.

When the Legislature passed the Department of Education budget this summer, it inserted a ban on funding Common Core implementation — despite three years of preparation by teachers and school administrators.

The House established a special subcommittee to further examine Common Core. That subcommittee’s chairman, state Rep. Tim Kelly, R-Saginaw Township, urged the House Education Committee on Thursday morning to lift the ban.

Kelly said his subcommittee held more than 17 hours of testimony, and spent “an awful amount of time and an awful amount of effort getting to this point.”

“It is my considered opinion that we move forward with Common Core and lift the pause,” Kelly said.

The House Education Committee voted on Thursday morning to support the resolution by an 11-5 margin, while the full House approved it later in the day by an 85-21 tally.

“Representatives from both sides of the aisle worked together for our number one priority: our children,” said state Rep. Theresa Abed, D-Grand Ledge.

The state would face the following consequences for failing to implement Common Core:

  • Michigan will lose its flexibility waiver to the federal No Child Left Behind Act, immediately making every school in Michigan accountable for having 100 percent of students proficient in math and reading.
  • Not a single public school will qualify as making AYP, resulting in NCLB sanctions like providing students with choice and transportation to other school districts, costly tutoring services, and much more.
  • Local districts will once again have to change learning standards for teachers and students, and will be forced to base teacher evaluations on the old MEAP and Michigan Merit Exam.
  • School districts will lose untold amounts of federal Title I funds that would have otherwise gone to help underprivileged students.

The Common Core State Standards have strong support from educators, as more than 75 percent of National Education Association members either support the standards wholeheartedly or with some reservations, according to a poll released earlier this month by the NEA.


text:
A History of North Texas Men's Golf

A golf magazine once called the University of North Texas the "Notre Dame" of men's golf -- for a very good reason.  With 83 tournament championships, including four NCAA crowns and 30 conference titles to its credit, North Texas has earned international recognition in the sport.

In all, the Mean Green have competed in the NCAA Tournament 34 times as a team and placed in the top 10 on 16 of those occasions. The program's long list of successes also includes seven Lone Star Conference titles, two Gulf Coast Conference championships, 13 Missouri Valley Conference titles, three Southland Conference championships, three Sun Belt Conference championships one Big West Conference title and now one Conference USA championship.

In 2011 the Mean Green received its first at-large bid to the NCAA Tournament in the modern era.  North Texas then captured consecutive conference titles in 2012 and 2013 for the first time since 1974-75. In 2015 the Mean Green captured the first C-USA title and their third league crown in the last four seasons.

North Texas sponsored its first varsity golf team in 1939, but much of the squad's history was written after Fred Cobb, a college golf pioneer, was named head coach in 1946. He saw his efforts pay off just two years later when the Eagles went undefeated and untied in 11 matches and won three tournaments.

Cobb's 1949 team garnered its first of four consecutive NCAA championships in 1949. The many standouts who donned the green and white during that period included Billy Maxwell, Don January, L.M. Crannell Jr., Buster Reed, Palmer Lawrence, Gene Towry, Joe Conrad, Bill Turner, Stan Mosel, A.J. Triggs and Marion Hiskey.

During Cobb's reign, the Mean Green fashioned a 72-10-3 record. Nine of the defeats, however, came in his first two seasons at the helm.

Following Cobb's death in 1955, Herb Ferrill took over the program. Among the team's accomplishments during his 30 years as head coach were two runner-up finishes and two third-place finishes at the NCAA Championships and 13 Missouri Valley Conference titles.

Since the All-America team was created in 1958, a host of North Texas players have earned selection to the elite group, including Dick Whetzle, Dick Smith, Bobby Greenwood, Frank Luke, Don Wilson, Ron Folk, Jimmy Clayton, Jerry Greiner, Guy Collins, John Granger, Doug Higgins and Mike McCaffrey.  Many of them went on to enjoy professional careers.

Under current head coach Brad Stracke, the program is having a rebirth to national prominence. After capturing the first Conference USA title in school history in 2015 and winning the third league crown in four years, Stracke was the C-USA Coach of the Year. It is the second time he has been named Coach of the Year in the last three seasons.

In 2013, Rodolfo Cazaubon was named to Golfweek's All-America team as he was tabbed as an honorable mention pick after his record-breaking season. Cazaubon became the first North Texas golfer to be named an All-American since Mike McCaffrey in 1992 and is the 13th player in school history to earn the honor, picking up the Mean Green's 21st All-America award since 1958.

2015 saw the Mean Green advance to the NCAA Tournament for the 34th time in school history and Juan Munoz win the Conference USA championship. Freshman Michael Cotton was named the C-USA All-Freshman team and North Texas finished the season ranked in the top-75 for the third time in the last four seasons.

Additonally former North Texas golfers Carlos Ortiz and Cazaubon have been enjoying success on the PGA Tour. Ortiz was the 2014 Web.com Tour Player of the Year and is a full-time member of the PGA Tour. Cazaubon is working his way towards the PGA Tour as well, having captured one PGA Tour Latinoamerica event.

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text:
WASHINGTON – President Obama announced his pick for US Trade Representative is Mike Froman, a national security and economic advisor to the president. He will succeed Ron Kirk, who resigned in March, if confirmed by the US Senate.

“He's been a key negotiator alongside Ron Kirk on those trade agreements for South Korea, Colombia, and Panama, which support tens of thousands of American jobs,” said President Obama.

Froman served during the Clinton administration as chief of staff to Treasury Secretary Robert Rubin. He also worked as deputy assistant secretary for Eurasia and the Middle East. Before joining the Obama administration, he held various positions at Citigroup. He also was a senior fellow at the Council of Foreign Relations.

“He has won the respect of our trading partners around the world,” the President continued. “He has also won a reputation as being an extraordinarily tough negotiator while doing it. He does not rest until he’s delivered the best possible deal for American businesses and American workers. He’s fought to make sure that countries that break the rules are held accountable.”


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text:
Joshua L. Dunaief, MD, PhD

faculty photo
Adele Niessen Professor of Ophthalmology
Department: Ophthalmology
Graduate Group Affiliations

Contact information
305 Stellar Chance
422 Curie Blvd.
Philadelphia, PA 19104-6100
B.A. (Biology)
Harvard University (magna cum laude), 1987.
PhD (Microbiology)
Columbia University, 1994.
Columbia University, 1996.
Permanent link

Description of Research Expertise

Research Interests
Mechanisms of oxidative stress induced apoptosis in the retina

Key words: AMD, iron, oxidative stress, apoptosis, retina, aging, mitochondria.

Description of Research
Age related macular degeneration (AMD) is the most common cause of irreversible blindness, yet its pathogenesis is poorly understood. Evidence suggests that cumulative oxidative damage contributes to AMD and aging in general. My lab has found that AMD retinas have iron overload, which can increase oxidative stress. Increased understanding of retinal iron homeostasis may lead to treatments for AMD. To investigate the mechanisms of retinal iron regulation, we use transgenic mouse models, human retinal tissue, and a dual chamber tissue culture system to study iron transport. A mouse line deficient in the iron transporting ferroxidases ceruloplasmin and hephaestin develops age-dependent retinal iron overload and retinal degeneration with features of AMD (Hahn et al., PNAS, 2004). Recent research suggests that iron plays a key role in apoptosis induced by a variety of insults. Further investigation of the mechanisms of retinal iron homeostasis and of iron induced apoptosis are the focus of the lab.

Rotation Projects
1)Study mechanisms of retinal iron regulation by performing histology and immunofluorescence on retinal sections from transgenic and knockout mice. You will learn retinal anatomy and the techniques of ocular microdissection, cryosectioning, plastic sectioning and microscopy.

2)Test the potentially protective effects of iron chelators on cultured retinal cells. You will learn tissue culture, qPCR, and cell death assays.

Lab personnel:
Majda Hadziahmetovic, postdoc
Ying Song, research specialist
Jared Iacovelli, graduate student
Allan Hunter, K12 fellow
Natalie Wolkow, MD/PhD student
Steve Grieco, research assistant
Alyssa Cwanger, research assistant
Jennifer Lee, research assistant
Sally Chu, undergraduate student

Selected Publications

Li Y, Song D, Song Y, Zhao L, Wolkow N, Tobias JW, Song W, Dunaief JL: Iron-induced Local Complement Component 3 (C3) Up-regulation via Non-Canonical TGF-β Signaling in the Retinal Pigment Epithelium. Journal Biol Chem 290(19): 11918-34, May 2015.

Choi Soo Young, Baek Jeong-In, Zuo Xiaofeng, Kim Seok-Hyung, Dunaief Joshua L, Lipschutz Joshua H: Cdc42 and sec10 Are Required for Normal Retinal Development in Zebrafish. Invest Ophthalmol Vis Sci 56(5): 3361-70, May 2015.

Jiang Ruiwei, Hua Chao, Wan Yike, Jiang Bo, Hu Huiyin, Zheng Jiashuo, Fuqua Brie K, Dunaief Joshua L, Anderson Gregory J, David Samuel, Vulpe Chris D, Chen Huijun: Hephaestin and ceruloplasmin play distinct but interrelated roles in iron homeostasis in mouse brain. J Nutr 145(5): 1003-9, May 2015.

Hunter Allan A, Smit-McBride Zeljka, Anderson Rachel, Bordbari Matthew H, Ying Gui-Shuang, Kim Esther S, Park Susanna S, Telander David G, Dunaief Joshua L, Hjelmeland Leonard M, Morse Lawrence S: GSTM1 and GSTM5 Genetic Polymorphisms and Expression in Age-Related Macular Degeneration. Curr Eye Res Page: 1-7, Apr 2015 Notes: Epub ahead of print.

Guo LY, Alekseev O, Li Y, Song Y, Dunaief JL: Iron Increases APP Translation and Amyloid-Beta Production in the Retina. Exp Eye Res 129: 31-7, Dec 2014.

Wolkow Natalie, Li Yafeng, Maminishkis Arvydas, Song Ying, Alekseev Oleg, Iacovelli Jared, Song Delu, Lee Jennifer C, Dunaief Joshua L: Iron upregulates melanogenesis in cultured retinal pigment epithelial cells. Experimental eye research 128: 92-101, Nov 2014.

Song D, Grieco S, Li Y, Hunter A, Chu S, Zhao L, Song Y, DeAngelis RA, Shi L, Liu Q, Pierce EA, Nishina PM,Lambris JD, Dunaief JL: A murine Rp1 missense mutation causing protein mislocalization and slowly progressive photoreceptor degeneration Am J Pathol 184(10): 2721-9, Oct 2014.

Zhao L, Li Y, Song D, Song Y, Theur M, Cwanger A, Su G, Dunaief JL: A High serum iron causes mouse retinal iron accumulation caused by despite an intact blood-retinal barrier Am J Pathol. Aug 2014 Notes: Epub ahead of print.

Zhao L, Wang C, Song D, Li Y, Song Y, Su G, Dunaief JL : Systemic administration of the antioxidant/iron chelator alpha lipoic acid protects against light-induced photoreceptor degeneration in the mouse retina Invest Ophthalmol Vis Sci 55(9): 5979-88, Aug 2014.

Song Delu, Grieco Steve, Li Yafeng, Hunter Allan, Chu Sally, Zhao Liangliang, Song Ying, DeAngelis Robert A, Shi Lan-Ying, Liu Qin, Pierce Eric A, Nishina Patsy M, Lambris John D, Dunaief Joshua L: A Murine Rp1 Missense Mutation Causes Protein Mislocalization and Slowly Progressive Photoreceptor Degeneration. The American journal of pathology Jul 2014.

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Last updated: 06/02/2015
The Trustees of the University of Pennsylvania


text:
Right-wing media narrative on Christmas Day plot falling apart

The right-wing media narrative that the Obama administration endangered security by giving Miranda rights to alleged attempted Christmas Day bomber Umar Farouk Abdulmutallab is falling apart. Contrary to claims based on unnamed sources in the right-wing media, Obama administration officials agree that Abdulmutallab gave valuable intelligence during his first interrogation and that Abdulmutallab has begun divulging intelligence again.

Right-wing media run with false claim that Abdulmutallab was not interrogated

Media claim Abdulmutallab was not interrogated. On Fox News' Your World, pundit K.T. McFarland claimed that administration officials "just let this guy get -- not be interrogated." Similarly, The Weekly Standard's Stephen Hayes falsely claimed that Director of National Intelligence Dennis Blair "admitted that Abdulmutallab was not interrogated for intelligence purposes." In addition, Sean Hannity falsely claimed that Abdulmutallab was not interrogated, saying: "[W]e have an underwear bomber that has information, that wanted to kill 300 Americans and we don't interrogate the guy and we let him lawyer-up."

In fact, Abdulmutallab was interrogated and intelligence, law enforcement officials agree he gave valuable information. Blair stated on January 20, "The FBI interrogated Umar Farouk Abdulmutallab when they took him into custody. They received important intelligence at that time, drawing on the FBI's expertise in interrogation that will be available in the HIG [High-value detainee Interrogation Group] once it is fully operational." Additionally, FBI director Robert Mueller testified that interrogators interviewed Abdulmutallab "to gain ... intelligence about whether there's another bomb, whether other coconspirators, where'd he get the bomb, all of that information without the benefit of -- or within the Miranda warnings."

Abdulmutallab has cooperated with interrogators since being Mirandized

Media claim DNI Blair testified that intelligence was lost because of the handling of Abdulmutallab. In her National Tea Party Convention speech, Sarah Palin claimed that Abdulmutallab "was questioned for only 50 minutes," adding: "We have a choice in how to do this. The choice was only question him for 50 minutes and then read his Miranda rights. ... [T]here are questions we would have liked this foreign terrorist to answer before he lawyered up and invoked our U.S. constitutional right to remain silent." The Wall Street Journal previously claimed in an editorial that that Blair "told the Senate that by immediately handing Abdulmutallab to the civilian justice system, the government all but slammed the door on its ability to interrogate him thoroughly."

In fact, Abdulmutallab has cooperated with interrogators since being Mirandized. Responding to Senate Intelligence Committee chairwoman Sen. Dianne Feinstein in a February 2 hearing (accessed via the Nexis database), Mueller agreed that "Abdulmutallab has provided valuable information" and that "the interrogation continues despite the fact he has been Mirandized." Blair testified in the same hearing: "There are decisions that have to be made in which you balance the requirement for intelligence with the requirement for a prosecution and the sorts of pressure that you bring onto the people that you arrest in either form. It's got to be a decision made at the time. And I think the balance struck in the Mutallab was a very -- was an understandable balance. We got good intelligence, we're getting more."

Moreover, Reuters reported in a February 2 article that "a law enforcement official" said "Abdulmutallab is talking and has been talking since last week providing useful, actionable and current intelligence that we've been actively following up on." The New York Times also reported:

Umar Farouk Abdulmutallab, the Nigerian man accused of trying to blow up a jetliner bound for Detroit on Dec. 25, started talking to investigators after two of his family members arrived in the United States and helped earn his cooperation, a senior administration official said Tuesday evening.

Mr. Abdulmutallab, 23, began speaking to F.B.I. agents last week in Detroit and has not stopped, two government officials said. The officials declined to disclose what information was obtained from him, but said it was aiding in the investigation of the attempted terrorist attack.

"With the family, the F.B.I. approached the suspect," the senior administration official said, speaking to reporters at the White House on the condition of anonymity because of the pending legal case. "He has been cooperating for days."

Claim that administration hurt national security by disclosing Abdulmutallab's cooperation refuted

Fox forwarded claim that Obama administration hurt national security by disclosing Abdulmutallab's cooperation. Fox News has repeatedly forwarded Sen. Kit Bond's dubious claim that it was wrong to disclose that Abdulmutallab was cooperating with the investigation because, according to Bond, FBI officials, including Mueller, instructed members of the Senate Intelligence Committee that "keeping the fact of his cooperation quiet was vital to preventing future attacks against the United States." Indeed, Fox News' website FoxNation.com went so far as to ask: "Did Obama admin. help terrorists by saying undie bomber was talking?"

In fact, Intelligence Committee Chair Feinstein stated that administration didn't tell committee to keep quiet about Abdulmutallab's cooperation. A February 4 FoxNews.com article about Bond's criticism noted that "Feinstein added later that at no time in the briefing did Mueller say that Abdulmutallab's cooperation was not to be revealed" and that "Bond, however, did not attend Monday's briefing, but spoke separately with Mueller." Additionally, on February 4, Fox News national correspondent Catherine Herridge reported that "[t]wo law enforcement officials dispute Bond's characterization of the phone call with the FBI director. They claim Mueller was warning the senator that new information about Abdulmutallab could become public. The senator says others weren't on that call, he was, and he knows what happened."

Claim that Bush administration did not treat terrorism suspects in similar manner debunked

Perino claimed shoe bomber was handled differently because there was "no system in place" to hold Abdulmutallab in military custody. On Fox & Friends, former White House press secretary Dana Perino attempted to rebut the Obama administration's comparison of their use of civilian trials for alleged terrorists with the Bush administration's similar treatment of shoe bomber Richard Reid by falsely suggesting that "there wasn't a system in place" for former President Bush to order Reid to be held by the military.

Hundreds of detainees were placed in military custody before shoe bomber pleaded guilty and was sentenced. Reid was arrested in December 2001, pleaded guilty on October 4, 2002, and was sentenced on January 30, 2003. Soon after the war in Afghanistan began in October 2001, the United States began holding detainees in military custody. For instance, in the 2006 case of Hamdan v. Rumsfeld, the Supreme Court majority opinion stated that in November 2001, the plaintiff in that case, Salim Ahmed Hamdan, "was captured by militia forces and turned over to the U.S. military." In the 2004 case of Rasul v. Bush, Justice John Paul Stevens, writing for the majority, stated: "Petitioners in these cases are 2 Australian citizens and 12 Kuwaiti citizens who were captured abroad during hostilities between the United States and the Taliban. Since early 2002, the U.S. military has held them -- along with, according to the Government's estimate, approximately 640 other non-Americans captured abroad -- at the Naval Base at Guantanamo Bay." Additionally, Jose Padilla was initially held in the civilian court system after his arrest on a material witness charge and was transferred to military custody on June 9, 2002. And Yaser Hamdi was held in military custody at Guantánamo Bay beginning in January 2002 and transferred to a military brig in South Carolina in April 2002.

Bush Attorney General Ashcroft praised handling of Reid as an example of "progress because of the combined and cooperative efforts of law enforcement and intelligence." From an August 25 speech by then-Attorney General John Ashcroft:

Around this nation, we can point to quiet, steady progress because of the combined and cooperative efforts of law enforcement and intelligence:

132 individuals have been convicted or pled guilty, including shoe-bomber Richard Reid, "American Taliban" John Walker Lindh, six members of the Buffalo cell, and two members of the Detroit cell.

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text:
Thursday, August 20, 2009
  • AOL Sues Over Trademark

    AOL's Platform-A has sued rival for allegedly infringing on AOL's rights to the names and In papers filed this week in federal district court in Virginia, AOL argues that's name tricks customers into thinking the company is affiliated with the AOL brands and The Web giant is alleging trademark infringement and unfair competition. ...Read the whole story

  • How Ad Position Affects Conversion Rates

    For marketers wondering how conversion rates change depending on where ads appear on Web pages, Google Chief Economist Hal Varian appears to have an answer -- though he calls the problem "tricky," because Google ranks ads by bid times and ad quality, so ads in higher positions tend to have higher quality. ...Read the whole story

  • EBay Dumps Old Affiliate Model, Adopts Quality-Click Pricing

    EBay has revamped its affiliate program, replacing the cost-per-lead and rev-share models typical of affiliate marketing with a cost-per-click model. Changes in the eBay Partner Network have been underway for about a year, since eBay brought the affiliate program in house to get better acquainted with its top affiliate publishers and forge closer relationships with them. ...Read the whole story

  • Bigger Isn't Necessarily Better When It Comes To Online Ad Formats

    In most media, advertisers pay more for the biggest, and theoretically most noticeable advertising formats, because they believe they work better. But when it comes to online advertising, smaller, and ostensibly less expensive, may actually work better. That is the conclusion of new research unveiled this morning by advertising effectiveness researcher Dynamic Logic. ...Read the whole story

  • AMEX OPEN Forum To Bridge Social Media Divide

    American Express OPEN Forum has begun to develop tools that will allow small business owners to bridge the gap between building relationships and connecting through social media. Pulse, a feature scheduled for launch later this summer, will help business owners participate in Twitter conversations from the OPEN Forum platform, Marcy Shinder, vice president of brand management at American Express OPEN, tells Online Media Daily. ...Read the whole story

  • CareerBuilder Building Network Aimed At LinkedIn

    Taking direct aim at LinkedIn, CareerBuilder has launched a social network for job seekers named BrightFuse. "Online networking is an important piece of the puzzle for workers wishing to build professional relationships," said Liz Harvey, senior director of online products for CareerBuilder. ...Read the whole story

  • Old Phones Learn New Tricks

    Regular mobile phones are taking on more and more of the advanced features of smartphones as they strive to compete with growing popularity of high-end devices like the iPhone and BlackBerry. In its latest mobile-tracking report, market researcher NPD Group points out that feature phones still account for the vast majority of U.S. mobile phone sales, with 72% of the market in the second quarter. ...Read the whole story

  • MySpace Likes iLike To The Tune Of $20M

    In an effort to invigorate its fading star, MySpace on Wednesday announced the acquisition of popular music recommendation startup iLike. While the size of the deal was not disclosed, it was reportedly in the range of $20 million. MySpace CEO Owen Van Natta also rejected any idea that the acquisition was necessary to save MySpace Music from an untimely demise. ...Read the whole story

  • Time Warner, YouTube Strike Programming Deal
  • Missouri Woman Lands In Court For 'Cyberbullying' On Craigslist
  • MRM Names Speidel To SVP Post
  • FLO TV, Rentrak Partner On Mobile Measurement
A Brand's-Eye View of Behavioral Targeting

As click through rates, according to Doubleclick, have cratered at .1% on an industry average, everybody is looking for a solution to the performance crisis befalling our industry. ...More


text:
Aperghis, Storm in a head

Combining sound, words and images

At the heart of the world of Georges Aperghis, a composer without limits.

He was and he remains a radical figure. Composer Georges Aperghis' fondness for adventure withstands the test of time. Born in 1945 in Athens, he moved to France when he was 18 and it was with modern composers such as Pierre Schaeffer and Pierre Henry, or his fellow countryman Iannis Xenakis, that he learnt to sweep aside all categorisations. Today, at the head of a catalogue of more than a hundred works, Georges Aperghis pursues his quest for groundbreaking inventiveness in which the voice plays a Major role. But the man who pushes creativity beyond the limits, the undisputed hero of profuse sound, has the greatest respect and fondness for his performers.

It is through them, that the filmmaker Catherine Maximoff invites us into his special world: by speaking to us of Aperghis' music, by deciphering his written pieces between 1978 and 2004 ("it wasn't a score, confides one of the singers, it was a sort of living being that hated me…"), they also tell us who he is.

Georges Aperghis composer

Movie director : Catherine Maximoff
Collection : Juxtapositions
Musical period : Contemporary music

Duration : 57 min
Production date : 2006
Production : © Idéale Audience / Les Films du Présent / Arte France
Available version(s) : FR ST EN, FR

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Ursocol 150

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Kindly mention usage and side effects of ursocol 150mg. tablets

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Verwon Says:
Ursocol contains the active ingredient Ursodeoxycholic Acid, it most commonly used to treat Liver conditions and gall stones.

Side effects may include: nausea and drowsiness.

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mathew philip Says:
dear sirs,,
kindly advise the contents of ursocol 150...i am advised to
take 1 each at two times...

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Annapolis, MD

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Tapping into the Field at The Banyan Tree

  • February 3, 2014 · 7:30 PM

I love our new home at the Banyan Tree! Come and tap into your soul, One Love/the Universe/Spirit/your Higher Self/God/All That Is! Soar with the angels and pulse with Mother Earth!

I love these words by Stephen Schwartz: "There is is an enormous impulse to create and...true creation is an embrace. There is an enormous impulse to express the love, to be the love, to make the love manifest and there is an enormous impulse to put all of that in chains."
And what is that impulse to put it all in chains? It is feeling the need to control born out of fear fed by locked up pain. What I love so much about tapping is that it frees up the locked pain, brings down the intensity of the emotional reaction, the old patterning of the brain, giving us the inner space to breathe, to choose again, to be more mindful, expansive and willing to risk our distorted perceptions of what provides "safety."

It is this freedom that I hope that these healing meditations inspire.

May everyone's light shine with ever increasing effulgence!

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  • Wade

    Never saw a location posted with an address!

    February 4, 2014

    • Holly T.

      Hi Wade, I think I assumed that since the site has the address for the Banyan Tree and I've held it there 4 other times, that it would be there. My apologies...I'm going to post now again for the sessions and will make sure it's added. Warmest regards, Holly

      February 5, 2014

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How would you describe your overall health and what interested you in Kale U.?

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Red Sauce or Gravy Basics

  • March 8, 2014 · 5:00 PM
  • Naturally Delicious

Learn how to make red sauce from a few basic ingredients.  Sample some delicious foods with sauce and taste your own creation by the end of class.  All ingredients and tools are included and you will learn with a very hands on approach.  Everyone will be participating and cooking their own small serving of sauce.  We will also modify the basic recipe according to your preferences, with meat or vegetarian options.

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  • Jayne

    Thanks Mary for the hands-on cooking lesson. Enjoyed meeting everyone.

    1 · March 9, 2014

  • Maria D.

    A lot of fun. Everyone was so patient and kind.

    March 8, 2014

  • sarah.0818

    quick questions-I am coming this Saturday but I noticed that the time was originally 12-2, but now it is 5-7? I just wanted to make sure so I don't show up at the wrong time. Thanks!!

    March 6, 2014

    • Maria D.

      hey Sarah. The class is 5 to 7. I think I had a kids class 12-2, but this class you signed up for is def. 5-7. Look forward to meeting you.

      March 6, 2014

  • Jayne

    How long is the class?

    February 24, 2014

    • Maria D.

      The class would be about one hour to 1 1/2 hours.

      February 24, 2014

  • Kevin

    Hey, can't make this one, but hope to make another.

    February 10, 2014

  • Maria D.

    I am open to having a meetup outside of Kearny if someone is open to opening their kitchen to group or if a local church or resturant will make themselves available, if there is demand in your area. I will be having a meetup at my local library for which there will be no charge, but it will not be so hands on because we expect larger crowds. My qualifications are that of an experienced and passionate home cook and caterer.

    January 26, 2014

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    A former member

    I have three questions, are these meetings always going to be in Kearny? I live in northwestern NJ, and it is pretty far away. Second, will there always be a charge? What are the qualifications of the person teaching?

    January 26, 2014

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June 30, 2014 - 4 went

Jackson Park Library (Roanoke) Show & Tell on Monday June 30

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Faith F.

Goose Creek, SC

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Hi Everyone, My husband and I moved here in January. He has had a few years of Italian and is part Italian, I am Italian by marriage but love the language and the country! We will hopefully make it to meet ya'll soon. Faith and Ron Felice

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[Sydney] The 2nd annual Mises Seminar

Building upon last years successful event, we have managed to bring together some of best free-market economists and libertarian philosophers from around the world for a weekend of fun and lively discussion.

This years special international guest speaker is the prodigious Professor Walter Block. He will be joined by 10 other academic speakers from Australia.

For more information please visit: http://www.mises.org.au.

(feel free to buy tickets here or on our website; noting that there are over 100 people already attending)

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