Performance investigation of an innovative H-bridge derived multilevel inverter topology for marine applications

441-449An innovative single-phase and three-phase H-bridge derived multilevel inverter topology is being proposed in this manuscript. The proposed topology makes use of relatively fewer switching devices compared to conventional Cascaded H-Bridge (CHB) multilevel inverter. In other words, the proposed inverter topology is capable of producing more number of levels in the voltage waveform with same number of switching devices. It is also established in this paper, that this proposed topology is superior in terms of requirement of lesser number of gate driving circuits and reduction in the harmonic content in the output voltage waveform. The proposed inverter topologies are driven by SPWM modulation technique. These converter topologies are not only beneficial for the power conditioning systems in the power system network but also for the other novel applications like in marine ships. In this manuscript, the performance comparisons of the proposed inverter topologies with that of conventional topology based on simulation results with MATLAB/SIMULINK have been presented

ALL-OPTICAL METHOD FOR DISTORTION ELIMINATION IN PHASE-MODULATED MICROWAVE PHOTONIC LINKS

Microwave photonic systems arose from the need to accomplish engineering goals that were not possible in the electrical domain alone. One of the first applications of photonic systems was in long haul microwave signal transport, leveraging the wide bandwidth and low propagation loss afforded by optical fiber. As these microwave photonic links became more widespread, so too did the efforts to improve their performance, most importantly the desire to minimize noise and distortion within the link in order to maximize dynamic range and linear performance. In this thesis, we demonstrate a new class of methods for microwave photonic link linearization that connects insights from a seemingly unrelated field- nonlinear optics- with microwave photonics to enhance the distortion-free operation of these links. Finally, we show applications for these methods in other areas of microwave photonics, particularly microwave signal generation

PHYTOCHEMICAL AND ANTIOXIDANT ACTIVITY OF CINNAMOMUM TAMALA LEAF EXTRACT

Cinnamon tamala, is a tree that is also known as bay leaf or tejpatta, it is native to India and included in the family Lauraceae. It has been proved that this plant has various pharmacological activities such as anti-tumor, anti-inflammatory, anti-oxidant, etc. In this present study, the phytochemical profile of the leaf is investigated both qualitatively and quantitatively. After the phytochemical investigation of the leaf, antioxidant potency for free radical scavenging (ABTS and DPPH) was examined. The presence of various alkaloids, steroids, and flavones was revealed by qualitative assessment. Cinnamon oil exhibited highest antioxidant activity having IC50 value of 40.85± 4.96 and 18.57 ± 0.10μg/ml in DPPH and ABTS assa

Macro-to-Micro Interface for the Control of Cellular Organization

The spatial organization of cellular communities plays a fundamental role in determining intercellular communication and emergent behavior. Few tools, however, exist to modulate tissue organization at the scale of individual cells, particularly in the case of dynamic manipulation. Micromechanical reconfigurable culture achieves dynamic control of tissue organization by culturing adherent cells on microfabricated plates that can be shifted to reorganize the arrangement of the cells. Although biological studies using this approach have been previously reported, this paper focuses on the engineering of the device, including the mechanism for translating manual manipulation to precise microscale position control, fault-tolerant design for manufacture, and the synthetic-to-living interface.National Science Foundation (U.S.) (Faculty Early Career Development Program)National Institute of Diabetes and Digestive and Kidney Diseases (U.S.)David & Lucile Packard FoundationNational Institutes of Health (U.S.). Ruth L. Kirschstein National Research Service Awar

Antibiotic resistance pattern in intensive care unit of a tertiary care teaching hospital

Background: Antimicrobials are a major class of drugs prescribed in Intensive Care Unit (ICU). Widespread use of empirical antibiotic therapy has facilitated the emergence of drug resistance, since empirical therapy is very often initiated at the outset, even before culture and sensitivity reports are available. The problem of drug resistance is on a rise, therefore, this study was planned to assess the drug resistance and sensitivity patterns of the blood isolates recovered from ICU.Methods: An observational- prospective study was conducted in the Tertiary care teaching hospital over a period of twelve months to assess antibiotic resistance and sensitivity pattern. A total of 104 consecutive patients receiving antibiotics in the ICU and having blood cultures with significant growth were included in the study. Blood sample was collected and after obtaining a culture growth, the identification and antimicrobial sensitivity testing was done.Results: Blood stream infection by Gram-negative bacteria (50.96%) was more common than Gram-positive bacteria (49.04%). Coagulase negative Staphylococci (CoNS) was the predominant single blood culture isolate (35.58%). Klebsiella pneumoniae (13.46%), Escherichia coli (12.50%), Acinetobacter baumannii complex (7.69%) were commonly isolated gram negative organisms. Gram positive isolates were resistant to beta lactams in maximum patients whereas Tigecycline, Linezolid, Daptomycin, Vancomycin, Nitrofurantoin and Teicoplanin were sensitive against them. Common gram negative isolates were sensitive to Colistin and Tigecycline but resistant to most of the antibiotics.Conclusions: A preponderance of gram negative bacteria over gram positive bacteria was noted with a higher degree of resistance to most of the first line antimicrobial agents.

Clinical study of cases of intrauterine foetal death in a tertiary centre

Background: Foetal death at any stage of pregnancy is a tragic event and one of the unhappy events in the field of obstetrics. The present study was done to determine the probable etiology for antepartum and intrapartum foetal deaths and to study the role of antenatal care in prevention of intrauterine foetal deaths.Methods: The cases of intrauterine foetal deaths in OBGY department at MGM hospital, Kalamboli and Kamothe with either ultrasound reports proving Intrauterine foetal death  (IUFD) or diagnosed on clinical examination by absence of foetal heart rate with gestational age more than 28 weeks by dating from Naegle’s rule or by ultrasonography were studied. Inclusion criteria includes as following; 1) All cases of IUFD >28 weeks of gestation; 2) Baby weight of 1000 grams or more and exclusion criteria includes molar pregnancy.Results: The foetal death rate was 27.76/1000 births. Major causes of IUFD were PE and eclampsia (34.78%), unexplained (14.49%) and abruptio placentae (7.25%). Majority of the stillbirth were seen in preterm pregnancy between 34 - 36 (18.85%) weeks followed by 28 - 30 weeks (17.39%). Majority of foetuses were preterm and of birth weight between 1 - 1.5 kg (28.26%) followed by 1.5 - 2 kg (26.09%).Conclusions: Present studies showed that majority of IUFDs were preventable. Pre-eclampsia and abruption which are the major causes of IUFD can be reduced by improving education of the patient to avail obstetric care, more frequent visits for high risk pregnancies, timely reference to specialist. Early registration is an important pre-requisite for early detection of risk factors.

Cross-Layer Optimization on Different Data Rates for Efficient Performance in Wireless Sensor Network

The traditional protocols used in wireless sensor networks adhere to stringent layering approaches, which decreases the performance of the quality of service (Quality of Service) metrics. As per specifications 802.15.4, wireless sensor networks are inexpensive and energy efficient. It is essential for evaluating the performance of WSNs. Researchers have looked into the fundamental aspects of a single physical layer and the medium access control (MAC) layer protocol using methodologies calculated using several mathematical models or experimental approaches, respectively. In this research, we offer an improved cross-layer analytical model that utilises a thorough combining and interacting of a Markov chain model of the MAC layer's propagation with a model of the PHY layer's propagation. This combination and interaction are described in detail. Various Quality of Service (quality of service) statistics are presented and evaluated, and a cross-layer effectiveness degradation study is conducted under different inputs of multi-parameter vectors. Other parameters, such as Average Wait Time, Reliability, Failure Probability, and Throughput, have been estimated from the simulation results and contrasted with standardised models. The cross-layer model provides a more thorough performance study with various cross-layer parameter sets, some of which comprise distance, power transmission, and offered loads, among other things