Derivation of new double-input DC-DC converters using the building block methodology

In most power electronic systems, the instantaneous input and output power vary by time and are not exactly identical with each other. Hence, providing a good match between them is a complicated task to deal with if not impossible. Furthermore, due to the wide variation range of the processed power, the overall efficiency of the system is not high. The solution is to hybridize the system using an energy storage unit like in hybrid electric vehicles, power factor correction systems, and photovoltaic systems. Multi-input converters play a key role in such hybridized systems, where it is required to have more than one power source...In this thesis, a systematic approach to derive several new double-input converters using H-bridge cells or single-pole triple-throw switches as building blocks is proposed. Different operating modes and the switch realization of the new converters are obtained and their corresponding voltage ratios are derived. Bidirectional power flow is also considered. All of the proposed converters consist of only one inductor; hence, the number of passive elements that are required is reduced. The operating characteristics of the new converters are verified using simulation results --Abstract, page iii

Synthesis of Double-Input DC-DC Converters using a Single-Pole Triple-Throw Switch as a Building Block

Hybridizing power electronic systems using an energy storage unit has gained popularity in transportation and power system applications. This task has traditionally been performed by using several independent power electronic converters. Multi-input converters, due to their reduced part count and improved efficiency, seem to be an advantageous option to replace the conventional converters. A few multi-input converter topologies have been reported in the literature; however, there is not a systematic approach to derive them. Furthermore, all possible topologies are not completely explored and it is difficult to derive new converters from the existing topologies. Hence, in this paper, a systematic approach to derive multi-input converters by using single-pole triple-throw switches as building blocks is presented

Restricted Investment in Private Equity: The Volcker Rule\u27s Incursion Into Banking?

Investment in private equity originally came from individual investors and corporations. However, over the years institutional investors have become prominent in the investor pool with the hope of achieving risk adjusted returns. Banks have become significant sources of funds in the private equity market. Bank affiliate groups account for a significant share of the private equity activity as well as the banks’ own capital. A distinct feature of a leveraged buyout by a private equity firm as opposed to strategic buyouts and other transactions is the significant reliance on debt financing. Typically, shell companies with substantially no assets would be formed by the private equity firms to effect the buyout. A substantial portion of this buyout would be funded by investment banks or possibly commercial banks, issuing high yield debt and other related financial offerings. This structure makes the banks very crucial players in the buyout and exposes them directly to the risk of the upshot of the buyout. Private equity opens avenues for diversified and promising returns. But, investment in private equity, perceived as more risky and volatile as opposed to other publicly traded securities, is being viewed by the government as less favorable in the current market dynamics. The nature of these businesses being high leveraged, make them more likely to falter in a crisis, thus adding to the systemic risk of the investors. In 2007, the housing bubble burst and the economy took a hit, exposing a host of risky lending and investment practices. The banking sector was especially found at the center of the economic ruin. Banks involved in a variety of arenas outside the conventional commercial banking sphere became particularly critical in this economic situation. The regulators’ approach towards the banks has been censorious in various respects. Owing to the nature of private equity investment practice and the economic conditions of the US market, Section 619 of the Dodd Frank Act, known as the Volcker Rule, was proposed prohibiting banks from investing in proprietary trading and further banning investment in hedge funds and private equity, with the view that such funds can be alternative vehicles for proprietary trading. The regulatory agencies currently are in the process of formulating rules in connection with the new law. Having opened the floor for comment from various financial entities, experts, international organizations and individuals, the legislators have received mixed responses to the proposed rules. This paper critically examines the rules by putting forward different perspectives towards their implementation and effects

Dislodging Anchored Diagnoses: An Unusual Presentation Of Acute Appendicitis

Cognitive errors are the most common cause of diagnostic errors in the process of clinical decision making. Recently, there has been an immense focus on the new science of error prevention in health care. Anchored thinking or heuristics is a form of cognitive error that portrays shortcuts or abbreviated thinking in the light of diagnostic uncertainty. The risk is of comfort in a typical scenario and not being able to adapt to a new situation. Here we present an intriguing case of acute appendicitis in a patient who was initially admitted and treated for hypothermia and alcohol withdrawal. As the patient recovered from his withdrawal and neared the end of his hospital stay, he developed persistent leukocytosis, mild metabolic acidosis and vague abdominal discomfort, leading us to pursue further work up resulting in a new diagnosis. If unrecognized, delayed diagnosis and significant harm with potential for rupture of the appendix, peritonitis, significant morbidity and even mortality could have occurred. This case serves as an example of how to avoid errors resulting from heuristic thinking for the reason that incongruity of data was specifically looked for and consequently recognized

Stressor-Induced “Inflammaging” of Vascular Smooth Muscle Cells via Nlrp3-Mediated Pro-inflammatory Auto-Loop

Calcification of the vessel wall as one structural pathology of aged vessels is associated with high cardiovascular mortality of elderly patients. Aging is linked to chronic sterile inflammation and high burden of reactive oxygen species (ROS), leading to activation of pattern recognition receptors (PRRs) such as Nlrp3 in vascular cells. The current study investigates the role of PRR activation in the calcification of vascular smooth muscle cells (VSMCs). Therefore, in vitro cell culture of primary rat VSMCs and ex vivo aortic stimulations were used to analyze osteogenic, senescence and inflammatory markers via real-time PCR, in situ RNA hybridization, Western Blot, photometric assays and histological staining. Induction of ROS and DNA-damage by doxorubicin induces a shift of VSMC phenotype toward the expression of osteogenic, senescence and inflammatory proteins. Induction of calcification is dependent on Nlrp3 activity. Il-1 beta as a downstream target of Nlrp3 induces the synthetic, pro-calcifying VSMC phenotype. Inhibition of PRR with subsequent reduction of chronic inflammation might be an interesting target for reduction of calcification of VSMCs, with subsequent reduction of cardiovascular mortality of patients suffering from vessel stiffness

Dislodging Anchored Diagnoses: An Unusual Presentation Of Acute Appendicitis

Cognitive errors are the most common cause of diagnostic errors in the process of clinical decision making. Recently, there has been an immense focus on the new science of error prevention in health care. Anchored thinking or heuristics is a form of cognitive error that portrays shortcuts or abbreviated thinking in the light of diagnostic uncertainty. The risk is of comfort in a typical scenario and not being able to adapt to a new situation. Here we present an intriguing case of acute appendicitis in a patient who was initially admitted and treated for hypothermia and alcohol withdrawal. As the patient recovered from his withdrawal and neared the end of his hospital stay, he developed persistent leukocytosis, mild metabolic acidosis and vague abdominal discomfort, leading us to pursue further work up resulting in a new diagnosis. If unrecognized, delayed diagnosis and significant harm with potential for rupture of the appendix, peritonitis, significant morbidity and even mortality could have occurred. This case serves as an example of how to avoid errors resulting from heuristic thinking for the reason that incongruity of data was specifically looked for and consequently recognized

Maternal health interventions in resource limited countries: a systematic review of packages, impacts and factors for change

The burden of maternal mortality in resource limited countries is still huge despite being at the top of the global public health agenda for over the last 20 years. We systematically reviewed the impacts of interventions on maternal health and factors for change in these countries. A systematic review was carried out using the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Articles published in the English language reporting on implementation of interventions, their impacts and underlying factors for maternal health in resource limited countries in the past 23 years were searched from PubMed, Popline, African Index Medicus, internet sources including reproductive health gateway and Google, hand-searching, reference lists and grey literature. Out of a total of 5084 articles resulting from the search only 58 qualified for systematic review. Programs integrating multiple interventions were more likely to have significant positive impacts on maternal outcomes. Training in emergency obstetric care (EmOC), placement of care providers, refurbishment of existing health facility infrastructure and improved supply of drugs, consumables and equipment for obstetric care were the most frequent interventions integrated in 52%-65% of all 54 reviewed programs. Statistically significant reduction of maternal mortality ratio and case fatality rate were reported in 55% and 40% of the programs respectively. Births in EmOC facilities and caesarean section rates increased significantly in 71%-75% of programs using these indicators. Insufficient implementation of evidence-based interventions in resources limited countries was closely linked to a lack of national resources, leadership skills and end-users factors. This article presents a list of evidenced-based packages of interventions for maternal health, their impacts and factors for change in resource limited countries. It indicates that no single magic bullet intervention exists for reduction of maternal mortality and that all interventional programs should be integrated in order to bring significant changes. State leaders and key actors in the health sectors in these countries and the international community are proposed to translate the lessons learnt into actions and intensify efforts in order to achieve the goals set for maternal health

Pregled AC-DC i DC-DC pretvarača za primjene u LED rasvjeti

High-Brightness Light Emitting Diodes (HB-LEDs) are considered the future trend in lighting not only due to their high efficiency and high reliability, but also due to their other outstanding characteristics: chromatic variety, shock and vibration resistance, etc. Nevertheless, they need the development of new power supplies especially designed for boosting and taking advantage of their aforementioned characteristics. Besides, their behaviour is completely different from the rest of lighting devices and, consequently, it should be also taken into account in the design of the converters used to drive them. As a result, many well-known topologies have been optimized or redesigned in order to be used in LED–lighting applications and many new topologies have come up in the recent years with the same purpose. In this paper, the main HB-LED characteristics will be explained, highlighting how they influence the design of their power supplies. After, the main topologies will be presented from the simplest to the most complex ones, analysing their advantages and disadvantages.Svjetleće diode s visokom razinom svjetline (HB-LED) smatraju se budućim trendom u rasvjeti zahvaljujući ne samo visokom stupnju efikasnosti i pouzdanosti, nego i njihovim izvanrednim svojstvima: raznolikost boja, otpornost na udarce i vibracije i sl. Ipak, s ciljem potpunog iskorištenja prethodno spomenutih svojstava, potrebno je razviti nove, posebno osmišljene izvore napajanja. Osim toga, ponašanje im se posve razlikuje od ostalih tipova rasvjete što je potrebno uzeti u obzir pri projektiranju pretvarača za njihovo napajanje. Kao posljedica toga, mnoge su poznate topologije pretvarača optimirane ili preoblikovane posebno za primjenu u LED rasvjeti, a zadnjih nekoliko godina mnoge nove su se tek pojavile. U ovom članku objašnjena su osnovna HB-LED svojstva naglašavajući njihov utjecaj na razvoj izvora napajanja. Uz to, prikazane su osnovne topologije, od najjednostavnijih do najsloženijih, ujedno analizirajući prednosti i nedostatke pojedinih

Meningococcus serogroup C clonal complex ST-10217 outbreak in Zamfara State, Northern Nigeria.

After the successful roll out of MenAfriVac, Nigeria has experienced sequential meningitis outbreaks attributed to meningococcus serogroup C (NmC). Zamfara State in North-western Nigeria recently was at the epicentre of the largest NmC outbreak in the 21st Century with 7,140 suspected meningitis cases and 553 deaths reported between December 2016 and May 2017. The overall attack rate was 155 per 100,000 population and children 5-14 years accounted for 47% (3,369/7,140) of suspected cases. The case fatality rate (CFR) among children 5-9 years was 10%, double that reported among adults ≥ 30 years (5%). NmC and pneumococcus accounted for 94% (172/184) and 5% (9/184) of the laboratory-confirmed cases, respectively. The sequenced NmC belonged to the ST-10217 clonal complex (CC). All serotyped pneumococci were PCV10 serotypes. The emergence of NmC ST-10217 CC outbreaks threatens the public health gains made by MenAfriVac, which calls for an urgent strategic action against meningitis outbreaks

Maternal and child health interventions in Nigeria: a systematic review of published studies from 1990 to 2014

BACKGROUND: Poor maternal and child health indicators have been reported in Nigeria since the 1990s. Many interventions have been instituted to reverse the trend and ensure that Nigeria is on track to achieve the Millennium Development Goals. This systematic review aims at describing and indirectly measuring the effect of the Maternal, Newborn, and Child Health (MNCH) interventions implemented in Nigeria from 1990 to 2014. METHODS: PubMed and ISI Web of Knowledge were searched from 1990 to April 2014 whereas POPLINE® was searched until 16 February 2015 to identify reports of interventions targeting Maternal, Newborn, and Child Health in Nigeria. Narrative and graphical synthesis was done by integrating the results of extracted studies with trends of maternal mortality ratio (MMR) and under five mortality (U5MR) derived from a joint point regression analysis using Nigeria Demographic and Health Survey data (1990-2013). This was supplemented by document analysis of policies, guidelines and strategies of the Federal Ministry of Health developed for Nigeria during the same period. RESULTS: We identified 66 eligible studies from 2,662 studies. Three interventions were deployed nationwide and the remainder at the regional level. Multiple study designs were employed in the enrolled studies: pre- and post-intervention or quasi-experimental (n = 40; 61%); clinical trials (n = 6;9%); cohort study or longitudinal evaluation (n = 3;5%); process/output/outcome evaluation (n = 17;26%). The national MMR shows a consistent reduction (Annual Percentage Change (APC) = -3.10%, 95% CI: -5.20 to -1.00 %) with marked decrease in the slope observed in the period with a cluster of published studies (2004-2014). Fifteen intervention studies specifically targeting under-five children were published during the 24 years of observation. A statistically insignificant downward trend in the U5MR was observed (APC = -1.25%, 95% CI: -4.70 to 2.40%) coinciding with publication of most of the studies and development of MNCH policies. CONCLUSIONS: The development of MNCH policies, implementation and publication of interventions corresponds with the downward trend of maternal and child mortality in Nigeria. This systematic review has also shown that more MNCH intervention research and publications of findings is required to generate local and relevant evidence