SiNx/(Al,Ga)N interface barrier in N-polar III-nitride transistor structures studied by modulation spectroscopy.

Contactless electroreflectance studies coupled with numerical calculations are performed on in-situ SiNx capped N-polar III-nitride high electron mobility transistor (HEMT) structures with a scaled channel thickness in order to analyse the built-in electric field in the GaN channel layer. The experimentally obtained field values are compared with the calculated field versus channel thickness curves. Furthermore, the experimental and theoretical sheet carrier densities, ns, are evaluated. While a gradual decrease in carrier concentration with decreasing channel thickness is expected for N-polar structures, experimentally a sudden drop in the ns values is observed for samples with very thin channels. The additional loss in charge was associated with a change in the SiNx/AlGaN interface Fermi level at very thin channel thicknesses.

Mercury(II) selective sensors based on AlGaN/GaN transistors.

This work presents the first polymer approach to detect metal ions using AlGaN/GaN transistor-based sensor. The sensor utilised an AlGaN/GaN high electron mobility transistor-type structure by functionalising the gate area with a polyvinyl chloride (PVC) based ion selective membrane. Sensors based on this technology are portable, robust and typically highly sensitive to the target analyte; in this case Hg2+. This sensor showed a rapid and stable response when it was introduced to solutions of varying Hg2+ concentrations. At pH 2.8 in a 10-2 M KNO3 ion buffer, a detection limit below 10-8 M and a linear response range between 10-8 M-10-4 M were achieved. This detection limit is an order of magnitude lower than the reported detection limit of 10-7 M for thioglycolic acid monolayer functionalised AlGaN/GaN HEMT devices. Detection limits of approximately 10-7 M and 10-6 M in 10-2 M Cd(NO3)2 and 10-2 M Pb(NO3)2 ion buffers were also achieved, respectively. Furthermore, we show that the apparent gate response was near-Nernstian under various conditions. X-ray photoelectron spectroscopy (XPS) experiments confirmed that the sensing membrane is reversible after being exposed to Hg2+ solution and rinsed with deionised water. The success of this study precedes the development of this technology in selectively sensing multiple ions in water with use of the appropriate polymer based membranes on arrays of devices.

Steady-state carbamazepine pharmacokinetics following oral and stable-labeled intravenous administration in epilepsy patients: effects of race and sex.

Carbamazepine is a widely prescribed antiepileptic drug. Owing to the lack of an intravenous formulation, its absolute bioavailability, absolute clearance, and half-life in patients at steady state have not been determined. We developed an intravenous, stable-labeled (SL) formulation in order to characterize carbamazepine pharmacokinetics in patients. Ninety-two patients received a 100-mg infusion of SL-carbamazepine as part of their morning dose. Blood samples were collected up to 96 hours after drug administration. Plasma drug concentrations were measured with liquid chromatography-mass spectrometry, and concentration-time data were analyzed using a noncompartmental approach. Absolute clearance (l/hr/kg) was significantly lower in men (0.039 ± 0.017) than in women (0.049 ± 0.018; P = 0.007) and in African Americans (0.039 ± 0.017) when compared with Caucasians (0.048 ± 0.018; P = 0.019). Half-life was significantly longer in men than in women as well as in African Americans as compared with Caucasians. The absolute bioavailability was 0.78. Sex and racial differences in clearance may contribute to variable dosing requirements and clinical response.

Development and Validation of a Stability-indicating UV Spectroscopic Method for Candesartan in Bulk and Formulations.

A simple, specific, accurate and stability-indicating UV- Spectrophotometric method was developed for the estimation of candesartan cilexitil, using a Shimadzu, model 1700 spectrophotometer and a mobile phase composed of methanol: water in the ratio of 9:1 at wave length (λ(max)) 254 nm. Linearity was established for candesartan in the range of 10-90 µg/ml. The percentage recovery of was found to be in the range of 99.76-100.79%. The drug was subjected to acid, alkali and neutral hydrolysis, oxidation, dry heat, UV light and photolytic degradation. Validation experiments performed to demonstrate system suitability, specificity, precision, linearity, accuracy, interday assay, intraday assay, robustness, ruggedness, LOD, and LOQ. While estimating the commercial formulation there was no interference of excipients and other additives. Hence this method can be used for routine determination of candesartan cilexetil in bulk and their pharmaceutical dosage forms. The proposed method for stability study shows that there was appreciable degradation found in stress condition of candesartan.

Mapping soil textural fractions across a large watershed in north-east Florida.

Assessment of regional scale soil spatial variation and mapping their distribution is constrained by sparse data which are collected using field surveys that are labor intensive and cost prohibitive. We explored geostatistical (ordinary kriging-OK), regression (Regression Tree-RT), and hybrid methods (RT plus residual Sequential Gaussian Simulation-SGS) to map soil textural fractions across the Santa Fe River Watershed (3585 km(2)) in north-east Florida. Soil samples collected from four depths (L1: 0-30 cm, L2: 30-60 cm, L3: 60-120 cm, and L4: 120-180 cm) at 141 locations were analyzed for soil textural fractions (sand, silt and clay contents), and combined with textural data (15 profiles) assembled under the Florida Soil Characterization program. Textural fractions in L1 and L2 were autocorrelated, and spatially mapped across the watershed. OK performance was poor, which may be attributed to the sparse sampling. RT model structure varied among textural fractions, and the model explained variations ranged from 25% for L1 silt to 61% for L2 clay content. Regression residuals were simulated using SGS, and the average of simulated residuals were used to approximate regression residual distribution map, which were added to regression trend maps. Independent validation of the prediction maps showed that regression models performed slightly better than OK, and regression combined with average of simulated regression residuals improved predictions beyond the regression model. Sand content >90% in both 0-30 and 30-60 cm covered 80.6% of the watershed area.

Socio-economic inequalities in child health: recent evidence from India.

This paper analyses the Indian National Family Health Survey (2005-2006) data to present certain broad descriptive features of child health inequalities in India and their distribution across well-defined socio-economic groups classified by gender and sector-of-origin, and their dispersal across space. This study finds that poorer sections of the population are beleaguered with ill health whether in the quest for child survival or due to anxieties pertaining to child nutrition. The concentration index value for the indicators of under-five mortality, full immunisation and underweight outcomes at the national level is calculated to be -0.159, 0.204 and -0.158, respectively. The other disturbing finding here is that there are reigning regional and gender disadvantages irrespective of the developmental status of the State. This study would not only help policymakers to recognise these persistent inequalities but also would help understand health performance at the state and regional levels thus facilitating targeting intervention.

Efficacy of two multimodal treatments on physical strength of occupationally subgrouped male with low back pain.

OBJECTIVES: Some occupations are more prone to low back pain (LBP) due to their static work postures and work place design. Multidisciplinary pain programs have shown their effectiveness in the management of LBP in general population but which treatment and which segment of the population will be benefited more was not investigated yet. This study determines the effect of two treatment protocols on five occupationally subgrouped male LBP patients. METHODS: A total of 102 occupational male, 20-40 yrs of age, with sub-acute or chronic nonspecific LBP were randomized and treated either with conventional treatment a combination of two electrotherapy (ultrasound and short wave diathermy) and one exercise therapy (lumbar strengthening exercises) or dynamic muscular stabilization techniques (DMST) an active approach of stabilizing training. At the end of the treatment, subjects of both the groups were further stratified in five subgroups on the basis of their occupation. The pain was the primary outcome measure while physical strength [back pressure changes (BPC) and abdominal pressure changes (APC)] the secondary. RESULTS: The Pain, BPC and APC of all subgroups improved significantly (P < 0.01) in the both treatments but more in DMST. For each variable, improvement in subgroups differed within and between the treatments. Overall improvement in all assessed variables were evident on Desk workers followed by Shop keepers the most while BPC of Movement job, APC of Others and Pain of Sedentary and Shop keepers improved the least. CONCLUSIONS: Study concluded that for the management of occupational LBP, DMST is more effective than conventional treatment. The Pain of Sedentary and Shopkeepers and physical strength of Movement job and Others may need more clinical attention. Findings of this study may be helpful in the management of occupational LBP.

Potent bactericidal action of a flavonoid fraction isolated from the stem bark of Butea frondosa.

The flavonoid fraction isolated from the ethyl acetate fraction (BF-1) of Butea frondosa (L.) stem bark exhibited distinct antimicrobial activity when tested against 129 bacterial strains belonging to 9 different genera of both gram-positive and gram-negative types. Minimum inhibitory concentration (MIC) of the fraction BF-1 was determined following NCCLS guidelines using the agar dilution method. Twenty-four out of 36 strains of Staphylococcus aureus were inhibited by 50-200 mg/l of the fraction. This fraction also inhibited strains of Bacillus spp., Shigella spp., Salmonella spp. and even a few Pseudomonas at concentrations between 50-200 mg/l. Other bacteria including Escherichia coli, Vibrio cholerae and V. parahaemolyticus were moderately sensitive to BF-1. In the in vivo studies, this fraction offered significant protection to Swiss albino mice at a concentration of 80 microg/mouse (p<0.001) when they were challenged with 50 median lethal dose of Salmonella enteritidis NCTC 74. A fraction named BF-1 that was isolated from an ethyl acetate fraction of Butea frondosa provided protection against an infection from a Salmonella enteritidis NCTC strain.

Antibacterial Activity of Ethanol Extract of Andrographis paniculata.

In the present study the ethanol extract of the aerial part of Andrographis paniculata was prepared and evaluated for antimicrobial activity against eleven bacterial strains by determining minimum inhibitory concentration and zone of inhibition. Minimum inhibitory concentration values were compared with control and zone of inhibition values were compared with standard ciprofloxacin in concentration 100 and 200 mug/ml. The results revealed that, the ethanol extract is potent in inhibiting bacterial growth of both Gram-negative and Gram positive bacteria.

Newer approaches to the diagnosis of early onset neonatal sepsis.

Accurate and timely diagnosis of early onset neonatal sepsis remains challenging to the clinician and the laboratory. A test with a rapid turnaround time with 100% sensitivity, rather than high specificity, which allows accurate diagnosis and appropriate antimicrobial treatment or which allows antibiotics to be safely withheld in non-infected infants, is desirable. Many potential markers (acute phase reactants, cell surface markers, cytokines) are not routinely available to the laboratory, and most likely combinations of markers will ensure greater diagnostic accuracy. In the future, molecular biology techniques offer the prospect of rapid identification of both pathogens and antimicrobial resistance markers.

Uptake and distribution of natural radioactivity in wheat plants from soil.

The uptake of naturally occurring uranium, thorium, radium and potassium by wheat plant from two morphologically different soils of India was studied under natural field conditions. The soil to wheat grain transfer factors (TF) were calculated and observed to be in the range of 4.0 x 10(-4) to 2.1 x 10(-3) for 238U, 6.0 x 10(-3) to 2.4 x 10(-2) for 232Th, 9.0 x 10(-3) to 1.6 x 10(-2) for 226Ra and 0.14-3.1 for 40K. Observed ratios (OR) of radionuclides with respect to calcium have been calculated to explain nearly comparable TF values in spite of differences in soil concentration of the different fields. They also give an idea about the discrimination exhibited by the plant in uptake of essential and nonessential elements. The availability of calcium and potassium in soil for uptake affects the uranium, thorium and radium content of the plant. The other soil factors such as illite clays of alluvial soil which trap potassium in its crystal lattice and phosphates which form insoluble compounds with thorium are seen to reduce their availability to plants. A major percentage (54-75%) of total 238U, 232Th and 226Ra activity in the plant is concentrated in the roots and only about 1-2% was distributed in the grains, whereas about 57% of 40K activity accumulated in the shoots and 16% in the grains. The intake of radionuclides by consumption of wheat grains from the fields studied contributes a small fraction to the total annual ingestion dose received by man due to naturally existing radioactivity in the environment.

Environmental impact of coal industry and thermal power plants in India.

Coal is the only natural resource and fossil fuel available in abundance in India. Consequently, it is used widely as a thermal energy source and also as fuel for thermal power plants producing electricity. India has about 90,000 MW installed capacity for electricity generation, of which more than 70% is produced by coal-based thermal power plants. Hydro-electricity contributes about 25%, and the remaining is mostly from nuclear power plants (NPPs). The problems associated with the use of coal are low calorific value and very high ash content. The ash content is as high as 55-60%, with an average value of about 35-40%. Further, most of the coal is located in the eastern parts of the country and requires transportation over long distances, mostly by trains, which run on diesel. About 70% oil is imported and is a big drain on India's hard currency. In the foreseeable future, there is no other option likely to be available, as the nuclear power programme envisages installing 20,000 MWe by the year 2020, when it will still be around 5% of the installed capacity. Hence, attempts are being made to reduce the adverse environmental and ecological impact of coal-fired power plants. The installed electricity generating capacity has to increase very rapidly (at present around 8-10% per annum), as India has one of the lowest per capita electricity consumptions. Therefore, the problems for the future are formidable from ecological, radio-ecological and pollution viewpoints. A similar situation exists in many developing countries of the region, including the People's Republic of China, where coal is used extensively. The paper highlights some of these problems with the data generated in the author's laboratory and gives a brief description of the solutions being attempted. The extent of global warming in this century will be determined by how developing countries like India manage their energy generation plans. Some of the recommendations have been implemented for new plants, and the situation in the new plants is much better. A few coal washeries have also been established. It will be quite some time before the steps to improve the environmental releases are implemented in older plants and several coal mines due to resource constraints.

Regulation of nuclear radiation exposures in India.

India has a long-term program of wide spread applications of nuclear radiations and radioactive sources for peaceful applications in medicine, industry, agriculture and research and is already having several thousand places in the country where such sources are being routinely used. These places are mostly outside the Department of Atomic Energy (DAE) installations. DAE supplies such sources. The most important application of nuclear energy in DAE is in electricity generation through nuclear power plants. Fourteen such plants are operating and many new plants are at various stages of construction. In view of the above mentioned wide spread applications, Indian parliament through an Act, called Atomic Energy Act, 1964 created an autonomous body called Atomic Energy Regulatory Board (AERB) with comprehensive authority and powers. This Board issues codes, guides, manuals, etc., to regulate such installations so as to ensure safe use of such sources and personnel engaged in such installations and environment receives radiation exposures within the upper bounds prescribed by them. Periodic reports are submitted to AERB to demonstrate compliance of its directives. Health, Safety and Environment Group of Bhabha Atomic Research Centres, Mumbai carries out necessary surveillance and monitoring of all installations of the DAE on a routine basis and also periodic inspections of other installations using radiation sources. Some of the nuclear fuel cycle plants like nuclear power plants and fuel reprocessing involve large radioactive source inventories and have potential of accidental release of radioactivity into the environment, an Environmental Surveillance Laboratory (ESL) is set up at each such site much before the facility goes into operation. These ESL's collect baseline data and monitor the environment throughout the life of the facilities including the decommissioning stage. The data is provided to AERB and is available to members of the public. In addition, a multi-tier system of AERB permissions is in place to ensure that all aspects of safety have been considered before permission to operate is granted. The stages where permission of AERB is essential are site selection, design data, and several stages during construction and operation. The details required by AERB include provision for treatment and storage of radioactive waste, de-commissioning procedures and provision of costs. In addition to AERB, nuclear power plants have to comply with the requirements of Ministry of Environment and Forests and get their clearance. This is given on the basis of Environmental Impact Assessment Report which should satisfy the authorities that no ecological damage will be caused and the facility will not have adverse effect on the environment. In addition, the State Pollution Control Board where the facility is to be located has to permit the site of the plant for its proposed discharges into the environment. It is largely due to the above comprehensive regulatory controls that none of the plants in India had any accident during the last 34 decades of operation. The type of measurements carried out by the ESL's and results from a few typical ESL's will be presented.

Demography of Indian aging, 2001-2051.

India is the second largest country in the world, with 72 million elderly persons above 60 years of age as of 2001, compared to China's 127 million. One of the objectives of this paper is to assess the emerging scenario of elderly for the first half of the 21st century. According to projections, the elderly in the age group 60 and above is expected to increase from 71 million in 2001 to 179 million in 2031, and further to 301 million in 2051; in the case of those 70 years and older, they are projected to increase from 27 million in 2001 to 132 million in 2051. Among the elderly persons 80 and above, they are likely to improve their numbers from 5.4 million in 2021 to 32.0 million in 2051. The increasing number and proportion of elderly will have a direct impact on the demand for health services and pension and social security payments. Mobilizing resources for geriatric care and providing sufficient maintenance for the elderly will emerge as a major responsibility for heath-care providers and pension economists.

MR appearance of interpeduncular lipoma.

Interpeduncular lipoma (IPL) is a very rare benign intracranial lesion. Non-invasive diagnosis of this condition is important, as these lesions are usually asymptomatic and are found incidentally. We describe a rare case of IPL in a 35-year-old woman presenting with headache of long duration and a recent increase in severity and frequency of headache. There was no neurological abnormality on clinical examination. MR imaging demonstrated a homogeneous lobulated T1-hyperintense and T2-hypointense lesion in interpeduncular fossa. A T1-weighted fat suppression sequence with chemical shift method confirmed the fatty nature of the lesion. The patient was managed conservatively.

Giant-cell tumors of the patella.

This study describes the clinical, radiographic, and histopathologic features, and discusses the management options of 11 cases of benign giant-cell tumors of the patella seen over 20 years. Fine needle aspiration cytology was a useful preoperative diagnostic tool. Ptellectomy and reconstruction of the extensor apparatus is the favored treatment option with curettage and bone grafting restricted to selected localized lesions.

Delivery-related complications and determinants of caesarean section rates in India.

Caesarean section rates have been increasing worldwide, raising the question of the appropriateness of the selection of cases for the procedure. This paper examines the levels and correlates of delivery-related complications and caesarean section deliveries in 18 selected states of India in terms of specific maternal and institutional factors, using data from the National Family Health Surveys, 1992-93. Goa (15.3%) and Kerala (13.7%) were the two states with relatively higher caesarean section rates. There is reason to believe that current rates are part of a rising trend. This cannot be attributed entirely to the rise in institutional deliveries alone because of the strong association between caesarean sections and private sector institutions. Apart from the fact that the states of Kerala and Goa have relatively high caesarean section rates, in Andhra Pradesh, Bihar, Gujarat, Karnataka, Punjab and Uttar Pradesh the risk of undergoing caesarean section in private sector institutions is four or more times that in the public sector. It is possible that this extremely useful surgical procedure is being misused for profit purposes in the private sector in several states. There is therefore a need to examine this phenomenon using data disaggregated by the nature of caesarean sections, i.e. whether it was an elective or an emergency caesarean section along with the reasons for the choice.