902 research outputs found
The lower Krishna Basin trajectory: relationships between basin development and downstream environmental degradation
No full textRiver basin development / Lakes / Environmental degradation / Ecosystems / Mangroves / Water allocation / Groundwater / Water quality / Salinity / Irrigated farming / Institutions / Irrigation canals / Rural development
GABAergic neuroactive steroids: a new frontier in bipolar disorders?
No full textNeurosteroids are synthesized in the brain and modulate brain excitability. There is increasing evidence of their sedative, anesthetic and antiseizure properties, as well as their influence on mood. Currently neurosteroids are classified as pregnane neurosteroids (allopregnanolone and allotetrahydrodeoxycorticosterone), androstane neurosteroids (androstanediol and etiocholanone) or sulfated neurosteroids (pregnenolone sulfate and dehydroepiandrosterone sulfate). Both preclinical and clinical findings indicate that progesterone derivative neurosteroids such as allopregnanolone and allotetrahydrodeoxycorticosterone play a role in mood disorders. Clozapine and olanzapine, which were shown to be effective in stabilizing bipolar disorder, elevate pregnenolone levels in rat hippocampus, cerebral cortex, and serum. In lithium-treated mice, the blood levels of allopregnanolone and pregnenolone were elevated compared to control levels. Women diagnosed with bipolar disorder typically show symptomatic exacerbation in relation to the menstrual cycle, and show vulnerability to the onset or recurrence of mood disorders immediately after giving birth, when the levels of neurosteroid derivatives of progesterone drop. Whereas in women who had recovered from bipolar disorder, the plasma concentration of allopregnanolone was elevated compared to either healthy controls or women with major depressive disorder during the premenstrual period. During depressive episodes, blood level of allopregnanolone is low. Treatment with fluoxetine tends to stabilize the levels of neurosteroids in depression. These findings converge to suggest that these steroids have significant mood-stabilizing effect. This hypothesis is consistent with the observation that a number of anticonvulsants are effective therapies for bipolar disorder, a finding also consistent with the antiseizure properties of neurosteroids. Further exploration of action of neuroactive steroids is likely to open new frontiers in the investigation of the etiology and treatment of mood disorders, particularly bipolar disorders
Single stage soft-switched high-frequency transformer isolated AC-to-DC bridge converter and extension to multiphase converter
No full textThis thesis presents the operation, analysis, simulation and experimental results of a
single-phase single-stage soft-switched high frequency (HF) transformer isolated ac-to-dc
bridge converter with low total harmonic distortion (THD) and its extension to ac-to-dc
multiphase converter. A single-phase single-stage soft-switched ac-to-dc bridge converter
cell has been proposed based on a new gating scheme. Due to the discontinuous current
mode (DCM) operation of the boost inductor, natural power factor correction and low
THD are ensured. The single-stage ac-to-dc multiphase converter is realized based on this
bridge converter cell to reduce HF harmonic components in the line current.
The steady-state operation of the single-stage bridge converter is explained for all
operating modes. Intervals of operation in these modes are identified and analyzed. The
steady-state solutions are presented. Based on these solutions, design curves are obtained.
Design example of a 1.7 kW converter is presented to illustrate the design procedure.
Operational characteristics are obtained for different line and load conditions. PSPICE
simulation results for the designed converter are presented. An experimental prototype is
built to verify the operation and performance of the converter. All four switches in the
fixed frequency bridge converter undergo soft switching (common switch requires an
auxiliary circuit) for a wide line and load range.
A single-stage HF transformer isolated ac-to-dc multiphase converter is proposed. The
analyses of the single-stage bridge converter cell are extended to the multiphase
converter. It is shown that N = 3 is near the optimum number of cells to reduce the input
current HF harmonic components. A design example of a 166 to 260 V (rms) input, 420
V output, 5 kW converter switching at 50 kHz is presented. PSPICE simulation results
are obtained for the designed converter to study its performance for varying load and line
conditions. A 3-cell 1.5 kW experimental prototype is built and experimental results are
obtained. All the results show that HF harmonics in the line current are reduced and
output voltage ripple frequency is increased. Each cell handles equal power and all
bridge-switches are soft switched. As a result, uniform thermal distribution is obtained.
Small-signal analysis of the single-stage ac-to-dc bridge converter cell is presented for
all operating modes using state-space averaging technique. Based on this analysis, small
signal transfer functions are obtained. Frequency response of the transfer functions are
plotted using MATLAB program and verified by PSPICE simulation results. A closed
loop control system is designed and frequency response of the overall loop gain is
presented. Large-signal transient behavior of the converter cell is studied with open loop
using PSPICE simulation program for step change in line and load conditions. The
simulation results show that the closed loop system is required to improve the converter
performance during step increase in line voltage.Graduat
Fabrication of nanoadjuvant with poly-ɛ-caprolactone (PCL) for developing a single-shot vaccine providing prolonged immunity [Corrigendum]
No full textPrashant CK, Bhat M, Srivastava SK, et al. Int J Nanomedicine. 2014;9:937–950.On page 937, the author affiliations have been listed incorrectly. The correct author list is as follows:Chandravilas Keshvan Prashant1Madhusudan Bhat2Sandeep Kumar Srivastava2Ankit Saxena3Manoj Kumar4Amar Singh3Mohammed Samim5Farhan Jalees Ahmad6Amit Kumar Dinda21Faculty of Engineering and Interdisciplinary Sciences, Jamia Hamdard, New Delhi, India; 2Department of Pathology, 3Department of Transplant Immunology and Immunogenetics, All India Institute of Medical Sciences, New Delhi, India; 4Centre for Biomedical Engineering, Indian Institute of Technology, New Delhi, India; 5Department of Chemistry, Faculty of Science, Jamia Hamdard, New Delhi, India; 6Department of Pharmaceutics, Faculty of Pharmacy, Jamia Hamdard, New Delhi, IndiaRead the original articl
Birth size, risk factors across life and cognition in late life: protocol of prospective longitudinal follow-up of the MYNAH cohort
No full textIntroduction: For late-life neurocognitive disorders, as for other late-life chronic diseases, much recent interest has focused on the possible relevance of Developmental Origins of Health and Disease (DOHaD). Programming by undernutrition in utero, followed by overnutrition in adult life may lead to an increased risk, possibly mediated through cardiovascular and metabolic pathways. This study will specifically examine, if lower birth weight is associated with poorer cognitive functioning in late life in a south Indian population.Methods and analysis: From 1934 onwards, the birth weight, length and head circumference of all babies born in the CSI Holdsworth Memorial Hospital, Mysore, India, were recorded in obstetric notes. Approximately 800 men and women from the Mysore Birth Records Cohort aged above 55 years, and a reliable informant for each, will be asked to participate in a single cross-sectional baseline assessment for cognitive function, mental health and cardiometabolic disorders. Participants will be assessed for hypertension, type-2 diabetes and coronary heart disease, nutritional status, health behaviours and lifestyles, family living arrangements, economic status, social support and social networks. Additional investigations include blood tests (for diabetes, insulin resistance, dyslipidaemia, anaemia, vitamin B12 and folate deficiency, hyperhomocysteinemia, renal impairment, thyroid disease and Apolipoprotein E genotype), anthropometry, ECG, blood pressure, spirometry and body composition (bioimpedance). We will develop an analysis plan, first using traditional univariate and multivariable analytical paradigms with independent, dependent and mediating/confounding/interacting variables to test the main hypotheses.Ethics and dissemination: This study has been approved by the research ethics committee of CSI Holdsworth Memorial Hospital. The findings will be disseminated locally and at international meetings, and will be published in open access peer reviewed journals
Three-phase high-frequency transformer isolated soft-switching DC-DC resonant converters
No full textThere is an increasing demand for power converters with small size, light weight, high conversion efficiency and higher power density. Also, in many applications, there is a need for dc-to-dc converters to accept dc input voltage and provide regulated and/or isolated dc output voltage at a desired voltage level including telecommunications equipment, process control systems, and in industry applications.
This thesis presents the analysis, design, simulation and experimental results of three-phase high-frequency transformer isolated resonant converters. The first converter presented is a three-phase LCC-type dc-dc resonant converter with capacitor output filter including the effect of the magnetizing inductance of the three-phase HF transformer. The equivalent ac load resistance is derived and the converter is analyzed by using approximation analysis approach. Base on this analysis, design curves have been obtained and a design example is given. Intusoft simulation results for the designed converter are given for various input voltage and for different load conditions. The experimental verification of the designed converter performance was established by building a 300 W rated power converter and the experimental results have been given. It is shown that the converter works in zero-voltage switching (ZVS) at various input voltage and different load conditions.
A three-phase (LC)(L)-type dc-dc series-resonant converter with capacitive output filter has been proposed. Operation of the converter has been presented using the operating waveforms and equivalent circuit diagrams during different intervals. An approximate analysis approach is used to analyze the converter operation, and design procedure is presented with a design example. Intusoft simulation results for the designed converter are given for input voltage and load variations. Experimental results obtained in a 300 W converter are presented. Major advantages of this converter are the leakage and magnetizing inductances of the high-frequency transformer are used as part of resonant circuit and the output rectifier voltage is clamped to the output voltage. The converter operates in soft-switching for the inverter switches for the wide variations in supply voltage and load and it requires narrow switching frequency variation (compared to LCC-type) to regulate the output voltage.
A three-phase high-frequency transformer isolated interleaved (LC)(L)-type dc-dc series-resonant converter with capacitive output filter using fixed frequency control is proposed. The converter operation for different modes is presented using the operating waveforms and equivalent circuit diagrams during different intervals. This converter is modeled and then analyzed using the approximate complex ac circuit analysis approach. Based on the analysis, design curves were obtained and the design procedure is presented with a design example. The designed converter is simulated using PSIM software to predict the performance of the converter for variations in supply voltage and load conditions. The converter operates in ZVS for the inverter switches with minimum input voltage and loses ZVS for two switches in each bridge for higher input voltages.Graduat
A Study of the Queueing Systems M/G/1 and GI/M/1
No full textThis report examines single-server queueing systems, focusing on M/G/1 (Poisson arrivals with general service times) and GI/M/1 (general independent arrivals with negative exponential service times). Traditional approaches, often relying on transforms to analyze distributions, have been criticized for obscuring key behavioral details. The report explores more recent advancements and research in queueing systems. The author presents a simplified method for studying queueing systems that minimizes the use of transforms while maintaining analytical rigor, making it well-suited for teaching and practical applications. The report extends its applicability to systems with group arrivals and services, using Kendall’s notation to denote queue configurations
Effect of solvent on the morphology of MoS2 nanosheets prepared by ultrasonication-assisted exfoliation
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