Thermal conductivity-based hydrogen in argon detector (HAD): Design, development of instrumentation, and performance evaluation.

The Hydrogen in Argon Detectors (HADs) working on the principle of thermal conductivity difference between argon (reference) and argon + H2 (sample) in the cover gas of a sodium-cooled fast breeder reactor using the Wheatstone bridge circuit. The output of HAD is very sensitive to the gas flow rate and to the variation in ambient temperature. The RMSnoise of current was brought within ±1 µA by a constant current source across the bridge. The temperature correction factor fed in the processor brought down the RMSnoise in the HAD signal within ±2.4 mV than the uncorrected one having RMSnoise of ±230 mV. The filtered noise of HAD facilitates enhancing the detection limit of HAD down to 30 ppm (3σ) of hydrogen in argon.

Contact angle measurement system with liquid sodium in inert atmosphere.

Liquid sodium is the heat transport medium in fast breeder reactors due to its favorable chemical, physical, and nuclear properties. Wetting of liquid sodium with the material of reactor components is essential for the effective functioning of the reactor. Liquid sodium wetting plays a crucial role, such as in (i) heat transfer and (ii) image reconstruction under sodium ultrasonic scanners. Contact angle is the inverse measure of the wetting of liquids over solid surfaces. A contact angle measurement system was set up in an inert atmosphere glow box to study the wetting behavior of liquid sodium on reactor materials. The contact angle of liquid sodium on nickel surface was measured as a function of temperature, and the results obtained were found to be in good agreement with the literature values. The contact angle of liquid sodium on SS316LN as a function of temperature was measured for the first time using this facility.

Design, development, and instrumentation of isopiestic experimental setup.

An isopiestic experimental facility for the measurement of vapor pressures has been designed, fabricated, and commissioned. Using the vapor pressure data as a function of temperature, useful thermodynamic properties of alloys and compounds of interest can be derived. The isopiestic facility comprises a pair of furnaces, temperature controllers, thermocouple movement mechanism, user interface, and data collection. Four such experimental setups have been commissioned. This experimental facility is useful to determine the vapor pressures of a volatile component over the condensed phases as a function of temperature and composition. Using the vapor pressure data, the thermodynamic properties of various systems can be determined. The experimental setup was validated by a Pr-Cd isopiestic run, and the results are compared with the data reported in the literature.

Design and development of heater control circuit without temperature sensor for monitoring hydrogen in argon.

A thin film based tin oxide sensor is developed to monitor low levels of hydrogen (concentration ranging from 5 to 75 ppm) in the cover gas plenum of the fast breeder test reactor. The heater and the sensor patterns are integrated on a miniature alumina substrate, and necessary electrical leads are incorporated into it. For proper functioning of the sensor, the heater has to be maintained at a constant temperature of 350 °C. This paper gives an outline of the electronics developed to measure the sensor signal and to control the heater temperature. The major challenge in this work is that there was no provision for embedding a temperature sensor on the heater surface due to physical constraints. This constrained the maintenance of a constant heater temperature for the proper functioning of the sensor. This led us to develop and demonstrate a heater control circuit without a temperature sensor to maintain a fixed temperature for monitoring hydrogen in argon, and electronics for the above-mentioned circuitry is discussed.

Design and development of instrumentation for the measurement of sensor array responses.

Indigenous instrumentation has been designed and developed for the measurement of the concentration of analytes from eight conductometric metal oxide sensors. The hardware scheme of instrumentation is based on the astable multivibrator configuration. The hardware measures the resistance output from the sensors, conditions, processes, and displays the data on the liquid crystal display. An 8051 based processor averages the data, converts them into engineering units, and sends them to remote PC through ethernet communication for post-data analysis. A graphical user interface (GUI) is developed to acquire, monitor, and display the eight channels' sensor output. GUI plots the online data and offline data as a popup window. The hardware and software of the instrument were tested with standard resistors for calibration and found that in-house developed instrumentation is able to measure with an accuracy of ±0.5% with a resolution of 500 Ω. The instrument has been tested with a semiconductor metal oxide sensor, viz., chromium niobate (CrNbO4).

AllerBase: a comprehensive allergen knowledgebase.

Database URL: http://bioinfo.net.in/AllerBase/Home.html.

Application of principal component analysis to gas sensing characteristics of Cr0.8Fe0.2NbO4 thick film array.

The transient changes in resistances of Cr0.8Fe0.2NbO4 thick film sensors towards specified concentrations of H2, NH3, acetonitrile, acetone, alcohol, cyclohexane and petroleum gas at different operating temperatures were recorded. The analyte-specific characteristics such as slopes of the response and retrace curves, area under the curve and sensitivity deduced from the transient curve of the respective analyte gas have been used to construct a data matrix. Principal component analysis (PCA) was applied to this data and the score plot was obtained. Distinguishing one reducing gas from the other is demonstrated based on this approach, which otherwise is not possible by measuring relative changes in conductivity. This methodology is extended for three Cr0.8Fe0.2NbO4 thick film sensor array operated at different temperatures.

Identification of ligand binding pockets on nuclear receptors by machine learning methods.

Nuclear receptors constitute a super family of protein hormones that serve as transcription factors. They typically reside in the cytosol and, after ligand binding, migrate to the nucleus to exert their biological action. Ligands are lipophilic, small molecules including retinoids, steroids, thyroxine, and vitamin D. Nuclear receptors being important regulators of gene expression, constitute 13% of proteins targeted by various drugs. Thus it becomes important to identify the ligand binding pockets on these proteins. Support Vector Machine (SVM) classifier was built to identify nuclear receptor ligand binding pockets. Positive dataset consisted of the ligand binding pockets of known nuclear receptor-ligand complex structures. Negative dataset consisted of ligand binding pockets of proteins other than nuclear receptors and nonligand binding pockets of nuclear receptors. SVM model yielded a 10 fold cross-validation accuracy of 96% using linear kernel. Also, it is helpful to find out the class of nuclear receptor in order to design a "class-specific" drug. In case of the multiclass nuclear receptor dataset comprising of nuclear receptors belonging to three different classes, SVM model for classification yielded an average 10-fold cross validation accuracy of 92 % for this dataset. SVM algorithm identifies and classifies nuclear receptor binding pockets with excellent accuracy. Top ranked features indicate the hydrophobic nature of ligand binding pocket of nuclear receptors. Conserved Leucine and phenylalanine residues form a distinguishing feature of these binding pockets. Along-with identification of NR binding pockets, important top ranked features are listed which would be useful in screening of possible drug molecules with NRs as molecular targets.

Advantages of collagen based biological dressings in the management of superficial and superficial partial thickness burns in children.

Collagen based dressings for acute burn wound management have been extensively used in India, particularly in the city of Chennai. Due to the high levels of humidity in our city, closed dressings become infected and treatment with topical antimicrobials, like Silver Sulfadiazine cream, quickly become desiccated. Collagen membrane dressings were manufactured by the biomaterial laboratory of the Central Leather Research Institute (CLRI), Government of India in Chennai, and then the process was patented. Collagen was extracted from bovine skin and Achilles tendons, and then reconstituted. This was used on burn wounds as dressings after clearance from the Institutional Review Board and Ethics Committees of the Hospital and CLRI. Continued research in this field to enable resulted in the design of silver sulphadiazine loaded alginate microspheres which were embedded in the reconstituted collagen. Controlled delivery of silver sulphadiazine. This collagen membrane was used in chronic infected burns. Low molecular weight heparin was given subcutaneously to improve wound healing in burn injuries and collagen membrane dressings were also applied. After several trials the process technology was patented. The advantages and disadvantages of the collagen membrane cover is elaborated in a group of 487 pediatric burn patients. The trial was conducted at the burn unit of Kanchi Kamakoti Childs Trust Hospital (KKCTH) in Chennai, India.

Pansements à base de collagène pour la gestion des blessures par brûlure ont été largement utilisés en Inde, en particulier dans la ville de Chennai. En raison des niveaux élevés d'humidité dans notre ville, les pansements fermées deviennent infectés et les traitements par les antimicrobiens topiques, comme la crème de sulfadiazine d'argent, deviennent vite desséchées. Le laboratoire de biomatériaux de l'Institut central de recherche sur le cuir (ICRC), gouvernement de l'Inde à Chennai, a fabriqué les pansements de membrane de collagène et le processus de fabrication a été breveté. Le collagène a été extrait de peau de bovin et de tendons d'Achille. Suite à l'autorisation de la commission de révision institutionnelle et les comités d'éthique de l'hôpital et l'ICRC, le collagène a été reconstitué et a été utilisé sur les brûlures comme pansements. Poursuite des recherches dans ce domaine a abouti à la conception des microsphères d'alginate chargées d'argent sulphadiazine qui ont été intégrées dans le collagène reconstitué. Cela a permis la libération contrôlée de sulfadiazine d'argent. Cette membrane de collagène a été utilisée dans les brûlures chroniques infectées. Les héparines de bas poids moléculaire ont été mises par injection sous-cutanée pour améliorer la cicatrisation des blessures par brûlure, et des pansements à membrane de collagène ont également été appliquées. Après plusieurs essais, la technologie de procédé a été breveté. Les avantages et les inconvénients de la couverture de la membrane de collagène est élaboré dans un groupe de 487 patients pédiatriques brûlés. Le procès s'est déroulé à l'unité des grands brûlés de l'hôpital Kanchi Kamakoti Childs Trust à Chennai, en Inde.

Hybrid biogeography based simultaneous feature selection and MHC class I peptide binding prediction using support vector machines and random forests.

Accurate detection of peptides binding to specific Major Histocompatibility Complex Class I (MHC-I) molecules is extremely important for understanding the underlying process of the immune system, as well as for effective vaccine design and developing immunotherapies. Development of learning algorithms and their application for binding predictions have thus speeded up the state-of-the-art in immunological research, in a cost-effective manner. In this work, we propose the application of a hybrid filter-wrapper algorithm employing concepts from the recently developed biogeography based optimization algorithm, in conjunction with SVM and Random Forests for identification of MHC-I binding peptides. In the process, we demonstrate the effectiveness of this evolutionary technique, coupled with weighted heuristics, for the construction of improved prediction models. The experiments have been carried out for the CoEPrA competition datasets (accessible online at: http://www.coepra.org) and the results show a marked improvement over the winner results in some situations and comparably good with regard to others .We thus hope to initiate further research on the application of this new bio-inspired methodology for immunological research.

Current scenario in chemical burns in a developing country: Chennai, India.

Chemical burns are not uncommon in India. Both accidental and non-accidental chemical burns are encountered in our setting. In the paediatric age group, chemical burns are mainly accidental. Analysis of chemical burn admissions to the Burn Units of a medical college hospital, and to an exclusively tertiary care children's hospital in Chennai, India, from 2001 to 2010 is described. A total number of 75 adults and 38 children are included in the study. Detailed analysis of age, sex, percentage of burn total body surface area (TBSA %), causative agents, aetiology (accidental or non-accidental), treatment instituted, mortality, and outcome are reported.

Profile of burn sepsis challenges and outcome in an exclusive children's hospital in Chennai, India.

A group of 273 paediatric patients admitted to Kanchi Kamakoti Childs Trust Hospital Burn Unit, Chennai, India between the years 2004 to 2010 were analysed retrospectively. Of these, 89 were suffering from sepsis and septic shock and 15 died. Strict adherence to antibiotic administration and to the Paediatric Intensive Care Unit (PICU) and management protocol improved the outcome, especially in 2009 and 2010.

A challenging case of total phalloplasty.

Plastic surgery continues to maintain a prominent presence in the evolution of male genital reconstruction. In this case report, we are presenting a case of post-electric burn with a total loss of penis. Sustaining other major injuries following an electric burn with loss of right upper limb and extensive tissue damage to left upper limb, abdomen and both thighs, this young male patient was initially managed from life-threatening problems. With many options closed following a major electric burn and its acute management, penile and urethral reconstruction was a unique and a great challenge in this patient. Heeding to the patient's wish of male pattern micturition, we had performed a successful reconstruction of urethra and entire phallus with groin flap.

Defensinpred: defensin and defensin types prediction server.

Defensins are considered to play an important role in the innate immune system of virtually all life forms, from insects and plants to amphibians and mammals. They are classified into alpha, beta and theta-defensins. Fast and accurate computational prediction of defensin and defensin types will help in annotating unidentified defensin novel peptides. Identified defensins, owing to their small length and potent antimicrobial activity can be used effectively for development of new clinically applicable antibiotics. Thus predicting the defensin candidates will aid in accurate identification of novel peptide drugs. Support vector machines prediction model accuracy was 99% for defensin and defensin types. The results indicate that it is most accurate and efficient prediction method for defensin peptides. User friendly defensin web server is provided at www.defensinpred.cdac.in for the benefit of scientific community.

ClassAMP: a prediction tool for classification of antimicrobial peptides.

Antimicrobial peptides (AMPs) are gaining popularity as anti-infective agents. Information on sequence features that contribute to target specificity of AMPs will aid in accelerating drug discovery programs involving them. In this study, an algorithm called ClassAMP using Random Forests (RFs) and Support Vector Machines (SVMs) has been developed to predict the propensity of a protein sequence to have antibacterial, antifungal, or antiviral activity. ClassAMP is available at http://www.bicnirrh.res.in/classamp/.

SVM prediction of ligand-binding sites in bacterial lipoproteins employing shape and physio-chemical descriptors.

Bacterial lipoproteins play critical roles in various physiological processes including the maintenance of pathogenicity and numbers of them are being considered as potential candidates for generating novel vaccines. In this work, we put forth an algorithm to identify and predict ligand-binding sites in bacterial lipoproteins. The method uses three types of pocket descriptors, namely fpocket descriptors, 3D Zernike descriptors and shell descriptors, and combines them with Support Vector Machine (SVM) method for the classification. The three types of descriptors represent shape-based properties of the pocket as well as its local physio-chemical features. All three types of descriptors, along with their hybrid combinations are evaluated with SVM and to improve classification performance, WEKA-InfoGain feature selection is applied. Results obtained in the study show that the classifier successfully differentiates between ligand-binding and non-binding pockets. For the combination of three types of descriptors, 10 fold cross-validation accuracy of 86.83% is obtained for training while the selected model achieved test Matthews Correlation Coefficient (MCC) of 0.534. Individually or in combination with new and existing methods, our model can be a very useful tool for the prediction of potential ligand-binding sites in bacterial lipoproteins.

Rapidly swept, ultra-widely-tunable 1060 nm MEMS-VCSELs.

Demonstrated are 1060 nm microelectromechanical-systems-based tunable vertical-cavity surface-emitting lasers (MEMS-VCSELs) with a 100 nm continuous tuning range under repetitively scanned operation at rates beyond 500 kHz and a 90 nm continuous tuning range under static operation. These devices employ a thin strained InGaAs multiple quantum well active region integrated with a fully oxidised GaAs/AlxOy bottom mirror and a suspended dielectric top mirror. The devices are optically pumped via 850 nm light. These ultra-widely tunable lasers represent the first MEMS-VCSELs reported in this wavelength range, and are ideally suited for application in ophthalmic swept-source optical coherence tomography.

High-sweep-rate 1310 nm MEMS-VCSEL with 150 nm continuous tuning range.

Microelectromechanical-systems-based vertical-cavity surface-emitting lasers (MEMS-VCSELs) capable of a 150 nm continuous tuning range near 1310 nm are demonstrated. These devices employ a thin optically pumped active region structure with large free-spectral range, which promotes wide and continuous tuning. To achieve VCSEL emission at 1310 nm, a wide-gain-bandwidth indium phosphide-based multiple quantum well active region is combined with a wide-bandwidth fully oxidised GaAs-based mirror through wafer bonding, with tuning enabled by a suspended dielectric top mirror. These devices are capable of being scanned over the entire tuning range at frequencies up to 500 kHz, making them ideal for applications such as swept source optical coherence tomography and high-speed transient spectroscopy.

Prehospital HMG Co-A reductase inhibitor use and reduced mortality in hemorrhagic shock due to trauma.

INTRODUCTION: 3-Hydroxy-3-methyl-glutaryl Co-A reductase inhibitors (HMG Co-A reductase inhibitors, statins) are commonly used medications for the control of serum cholesterol. Recent data suggests that these medications also modify the inflammatory pathways in sepsis, septic shock, and hemorrhagic shock due to ruptured abdominal aortic aneurysms. Statin use in hemorrhagic shock due to trauma, however, has conflicting data, with one study showing improvement, but only in certain subsets of patients. STUDY DESIGN: We retrospectively reviewed the medical records of patients from our institution's trauma registry database from January 2000 to December 2008. We included patients with an age greater than 45 years and an Injury Severity Score (ISS) greater than 15 with evidence of shock as follows: hypotension, elevated serum lactate, base deficit, metabolic acidosis, or objective evidence of end-organ malperfusion. We excluded patients with devastating head injury, patients with pre-existing advance directives directing against life-sustaining measures, patients for whom family or health care proxies withdrew support in 24 h or less, and patients who succumbed to their injuries in the first 24 h in the hospital. We compared age, gender, mortality, statin use, aspirin use, and Sequential Organ Failure Assessment (SOFA) scores. RESULTS: Mortality in the group without prehospital statin use was 38.1% (95% confidence interval [CI]: 28.4-48.8%) and mortality in the group with prehospital statin use was 8.3% (95% CI: 2.13-22.5%, P = 0.0009). The absolute risk reduction was 29.8% and the relative risk reduction was 78.1%. Survivors were statistically significantly younger than nonsurvivors in the group without prehospital statin use, but not in the group with documented prehospital statin use. There was no similar benefit to aspirin use. There were no significant differences in the SOFA scores, hospital length of stay (HLOS), or intensive care unit length of stay (ICU LOS) between statin users and nonusers. CONCLUSIONS: Prehospital HMG Co-A reductase use was associated with improved survival in a population with severe trauma and evidence of ongoing hemorrhagic shock.