High power-supply rejection current-mode low-dropout linear regulator

Power management components can be found in a host of different applications ranging from portable hand held gadgets to modern avionics to advanced medical instrumentations, among many other applications. Low-dropout (LDO) linear regulators are particularly popular owing to their: ease of use, low cost, high accuracy, low noise, and high bandwidth. With all its glory, however, it tends to underperform switched-mode power supplies (SMPS) when with comes to power conversion efficiency, although the later generates a lot of ripple at its output. With the growing need to improve system efficiency (hence longer battery life) without degrading system performance, many high end (noise sensitive) applications such as data converters, RF transceivers, precision signal conditioning, among others, use high efficiency SMPS with LDO regulators as post-regulators for rejecting the ripple generated by SMPS. This attribute of LDO regulators is known as power supply rejection (PSR). With the trend towards increasing switching frequency for SMPS, to minimize PC board real estate, it is becoming ever more difficult for LDO regulators to suppress the associate high frequency ripple since at such high frequencies, different parasitic components of the LDO regulator start to deteriorate its PSR performance. There have been a handful of different techniques suggested in the literature that can be used to achieve good PSR performance at higher frequencies. However, each of these techniques suffers from a number of drawbacks ranging from reduced efficiency to increased cost to increased solution size, and with the growing demand for higher efficiency and smaller power supplies, these techniques have their clear limitations. The objective of this research project is to develop a novel current-mode LDO regulator that can achieve good high frequency PSR performance without suffering from the afore mentioned drawbacks. The proposed architecture was fabricated using a proprietary 1.5 um Bipolar process technology, and the measurement results show a PSR improvement of 20dB (at high frequencies) over conventional regulators. Moreover, the proposed LDO regulator requires a small 15nF output capacitor for stability, which is far smaller than some of the currently used techniques.M.S.Committee Chair: Rincón-Mora, Gabriel; Committee Member: Ghovanloo, Maysam; Committee Member: Leach, W. Marshal

Dental students’ perceptions and feedback on teaching and learning pharmacology

Background: There is a shift in the teaching learning process with the advent of newer methodologies. The present study was conducted to obtain feedback from 2 year dental students regarding teaching and learning methodology and their perception about pharmacology.Methods: This was an observational, cross-sectional questionnaire based survey. A self-designed questionnaire containing 10 questions with 4-6 options regarding the teaching and learning methodology was given to 2nd year dental students. Responses was collected and data was compiled in Microsoft excel and statistically analyzed.Results: A total of 97 students participated in this survey. Students opinion revealed that, Gastrointestinal followed by general pharmacology and cardiovascular system were the most favorite topics. Majority preferred studying from “standard text books” and method of learning was “understanding” of the subject rather mugging. Majority of the students said that preferred lectures taken via LCD projectors and rated viva and MCQ as preferred method of evaluation university exams. Interactive classes and tutorials were the most preferred techniques.Conclusions: The study concluded that interactive classes and overhead /LCD based lectures should be inculcated in routine learning and teaching program of pharmacology. There is a need to qualitatively assess the various teaching and learning methods, so as to understand students views and their perception for improving teaching and learning pharmacology. The outcome will help us to modify and improve quality of under graduate dental pharmacology teaching and learning

Pharmacoepidemiological profile and appropriateness of drug use in paediatric diarrhoea patients: a cross sectional study in western India

Background: The background of the study was to analyze the prescribing pattern and appropriateness of drug treatment of diarrhoea.Methods: Total 194 pediatric patients with diarrhoea (140 admitted at tertiary care centre and 54 patients attended primary health care centre) were included and their demographic details; disease related parameters, drug treatment and adverse drug reactions were recorded. Appropriateness of drug treatment was analyzed using the WHO and Indian Academy of Pediatrics (IAP) guidelines for management of diarrhoea.Results: Most patients (27.32%) were less than 1 year of age and majority 54.64% were males. Most common presenting symptoms was diarrhoea with dehydration (100%) followed by vomiting (60%), fever (54.29%). Stool cultures were carried out only in 22.86% patients at tertiary health care centre while no investigations were carried out at PHC. Average number of drugs prescribed per patient was 8.25 ± 1.3. All the patients were given fluid replacement therapy. 94.29% and 85.19% patients were prescribed antimicrobials at tertiary centre (THC) and PHC respectively. Most common antibiotic used was cephalosporins (82%) followed by aminoglycosides (48.57%) of patients at THC while ofloxacin (82.60%) and metronidazole (17.40%) were commonly used at PHC.  Analgesic/antipyretic was required in 70.71% and 85.19% of patients at THC and PHC respectively. Comparing with the WHO diarrhoea management guidelines and IAP guidelines, only 8 (14.81%) prescriptions were considered as rational. 2.85% patients developed mucocutaneous rash as ADR.Conclusions: Inappropriate prescribing for diarrhoea is highly prevalent in society. Emphasis on proper diagnosis and treatment, education and availability of locally effective guidelines may help in a better and judicious use of drugs in children

Spectrum of clinical and biochemical profile and its importance in diabetic ketoacidosis: a tertiary care hospital experience in Gujarat

Background: Diabetes mellitus (DM) is a disorder of multiple etiologies, and diabetic ketoacidosis (DKA) is one of the life-threatening complications of DM. This study was aimed to study the clinical and biochemical profile of DKA patients. Methods: We conducted this retrospective study at a tertiary care hospital in Gujarat. We included total 100 patients above the age of 18 years having DM, presented with DKA. A detailed history, clinical examination and biochemical tests were carried out: random blood sugar, urinalysis, arterial blood gas analysis, serum ketone, HbA1c, serum creatinine, serum electrolytes- potassium and sodium and serum osmolality. The results were analysed using Microsoft excel. Results: Out of total 100 patients, 76 (76%) patients had type 1 DM and 24 (24%) had type 2 DM, 42 (42%) were in the age group of 18-30 years. The mean age was 39.75±12.14 years. There were 56 (56%) males and 44 (44%) females with male: female ratio of 1.3:1. Most common clinical features of DKA were nausea/vomiting (88%), breathlessness (43%) and fever (35%). The main biochemical parameters altered were blood sugar (>400 mg/dl in 41%) and serum ketones (≥5 in 84%) as well as majority of patients (64%) had their HbA1c level between 11-15% with the mean HbA1c value of 12.25±2.43%. Conclusions: DKA is a frequently observed emergency with high mortality rate. Education regarding symptoms of ketoacidosis, not missing insulin doses especially during illness, strict adherence to treatment and lifestyle modifications can greatly reduce DKA occurrence

Experimental Shear Study on Reinforced High Strength Concrete Beams Made Using Blended Cement

With the increased application of High Strength Concrete (HSC) inconstruction and lack of proper guidelines for structural design in India,behavioral study of high strength concrete is an important aspect ofresearch. Research on the behavior of HSC reinforced beams with concretestrength more than 60 MPa has been carried out in the past and is stillcontinuing to understand the structural behavior of HSC beams. Along withthe many benefits of the high strength concrete, the more brittle behavior isof concern which leads to sudden failure. This paper presents the behaviorof reinforced HSC beams in shear with considering the effects of variousfactors like shear reinforcement ratio, longitudinal reinforcement ratio, l/dratio (length to depth ratio), etc. Ten numbers Reinforced Concrete Beamsof various sizes using concrete mix with three different w/c ratios (0.46, 0.26and 0.21) were cast for shear strength assessment. The beams were tested insimply supported condition over two fixed steel pedestals with load rate of0.2 mm/minute in displacement control. Mid-point deflection was measuredusing LVDT. A comparative analysis of theoretical approaches of Eurocode, extension of current IS code up to M90 and the experimental datawas done to understand the behavior of beams. Shear capacities of beamswithout any factors of safety were used to assess the actual capacities andthen was compared with the experimental capacity obtained. Results ofthis study can be used in the design of high strength concrete and will bemore reliable in Indian continent as the regional materials and exposureconditions were considered

Otopathogenic Staphylococcus aureus Invades Human Middle Ear Epithelial Cells Primarily through Cholesterol Dependent Pathway

Chronic suppurative otitis media (CSOM) is one of the most common infectious diseases of the middle ear especially affecting children, leading to delay in language development and communication. Although Staphylococcus aureus is the most common pathogen associated with CSOM, its interaction with middle ear epithelial cells is not well known. In the present study, we observed that otopathogenic S. aureus has the ability to invade human middle ear epithelial cells (HMEECs) in a dose and time dependent manner. Scanning electron microscopy demonstrated time dependent increase in the number of S. aureus on the surface of HMEECs. We observed that otopathogenic S. aureus primarily employs a cholesterol dependent pathway to colonize HMEECs. In agreement with these findings, confocal microscopy showed that S. aureus colocalized with lipid rafts in HMEECs. The results of the present study provide new insights into the pathogenesis of S. aureus induced CSOM. The availability of in vitro cell culture model will pave the way to develop novel effective treatment modalities for CSOM beyond antibiotic therapy

BACTERIAL DISEASES OF LIVESTOCK ANIMALS AND THEIR IMPACT ON HUMAN HEALTH

Recently, whole world is facing the problem of infectious diseases related to animal diseases that pose significant threats to human health. In other words, humans may acquire zoonotic infections through various routes i.e. food, water etc. The transmission of certain bacterial diseases (through food and water) is one of the important cause of illness in both developing and developed countries. Most of the infectious pathogens that are normally reside in the intestinal tract of healthy animals and may transmit the disease through products (meat, milk or eggs) and faecal contamination of the environment. Normally, minute amount of intestinal contents are released and contaminate milk during milking; carcass at slaughter and egg during laying. Generally, risk associated with this type of contamination is somehow minimised where proper food hygiene is normally applied throughout the entire food chain from production, through processing to preparation at home. In this view, we provide some information about bacterial diseases of livestock animals and their effect or impact on human health.Â

The role of increased reactive oxygen species on 3T3-L1 preadipocytes differentiation

Differentiation of preadipocytes plays an important role in human physiology by accommodating adipocyte expansion and maintaining energy homeostasis. Any process that interferes with preadipocytes differentiation could alter energy homeostasis. In our study, we observed the effect of increased levels of ROS, which has been shown to affect adipocyte functioning, on preadipocytes differentiation. Our study shows that increased levels of ROS can inhibit 3T3-L1 preadipocytes differentiation. While the preadipocytes eventually became resistant to the increased levels of ROS, its effect on differentiation was already fixed. The mechanism by which increased levels of ROS impaired differentiation was by decreasing and delaying Cyclin D1 expression. This would affect the phosphorylation status of retinoblastoma protein which is required for cell cycle progression into the S-phase. Since clonal expansion was halted, the activity and expression of essential transcription factors needed for differentiation C/EBPβ and PPARγ were affected, leading to impaired differentiation. Furthermore, we have shown that once the increased ROS levels are restored to lower amounts, the 3T3-L1 preadipocytes were able to differentiate into mature adipocytes when exposed to MDI. The amount of differentiation observed was diminished compared to the normally differentiating 3T3-L1 preadipocytes, but was significantly greater than cells that kept differentiating in the presence of increased ROS. Overall, we have outlined the timeframe during which oxidative stress impairs 3T3-L1 preadipocyte differentiation. We have shown that, once that increased ROS levels are lowered, differentiation can be restored, but not to the same degree as unstressed differentiating 3T3-L1 preadipocytes

Management recommendations for pancreatic manifestations of von Hippel–Lindau disease

Von Hippel–Lindau disease (VHL) is a multineoplasm inherited disease manifesting with hemangioblastoma of the central nervous system and retina, adrenal pheochromocytoma, renal cell carcinoma, pancreatic neuroendocrine tumors and cysts, and neoplasms/cysts of the ear, broad ligament, and testicles. During 2018-2020, the VHL Alliance gathered several committees of experts in the various clinical manifestations of VHL to review the literature, gather the available evidence on VHL, and develop recommendations for patient management. The current report details the results of the discussion of a group of experts in the pancreatic manifestations of VHL along with their proposed recommendations for the clinical surveillance and management of patients with VHL. The recommendations subcommittee performed a comprehensive systematic review of the literature and conducted panel discussions to reach the current recommendations. The level of evidence was defined according to the Shekelle variation of the Grading of Recommendations, Assessment, Development, and Evaluation grading system. The National Comprehensive Cancer Network Categories of Evidence and Consensus defined the committee members' interpretation of the evidence and degree of consensus. The recommendations encompass the main aspects of VHL-related pancreatic manifestations and their clinical management. They are presented in a clinical orientation, including general planning of screening and surveillance for pancreatic neuroendocrine tumors, utility of biochemical biomarkers, the optimal choice for imaging modality, indirect risk stratification, indications for tissue sampling of VHL-related pancreatic neuroendocrine tumors, and interventions. These recommendations are designed to serve as the reference for all aspects of the screening, surveillance, and management of VHL-related pancreatic manifestations