Laboratories for an undergraduate course in power electronics

Laboratory exercises to accompany an undergraduate power electronics course are discussed. Topics include inductors, periodic steady state, drive circuits, PWM control, average switch models, and startup. These laboratories present an evolutionary sequence of increasingly difficult, design-oriented power electronics laboratories     

Age of onset of drug use and its association with DSM-IV drug abuse and dependence: results from the National Longitudinal Alcohol Epidemiologic Survey

Although adaptive explanations for menstruation go back at least twenty-five hundred years, in the last decade two new hypotheses have been advanced. The first suggests that menstruation evolved to cleanse the uterus of pathogens introduced by sperm, and the second argues that the function of endometrial regression (with the associated menstruation in humans) is to save energy by getting rid of tissue, rather than maintaining it in the absence of an available blastocyst. Both these suggestions may be questioned on the grounds that they do not take into account the physiology of the reproductive processes involved. Menstruation is not an independent physiological process and is unlikely to have been selected for independently of the evolutionary events that led to it. Furthermore, most primitive menstruating animals would have menstruated infrequently, and many may have reproduced or died without ever menstruating. In order to provide a context for understanding how menstruation may have come about, the evolution of the female vertebrate reproductive tract is briefly reviewed. In later stages, the coevolution of the embryo and uterus resulted in an intimate association between the trophoblast and the uterine blood vessels. As the embryo became more invasive, the uterus responded with increased cellular growth and differentiation of the endometrium to accommodate it. This reached its peak in mammals (such as rodents and humans), where the embryo passes through the epithelium into the endometrial stroma, which responds with differentiation of cells and blood vessels. Progesterone, secreted after ovulation, plays a crucial role in preparation for pregnancy. In addition to its well-known effects on the uterus, progesterone may be important in suppressing the inflammatory reaction that would be expected in response to the presence of a foreign body, such as an embryo. It is also suggested that vascular and cellular differentiation of the endometrial stroma has evolved by adaptation of the inflammatory (granulation tissue) reaction. When progesterone levels fall at the end of the cycle, there is tissue breakdown and bleeding. The uterus then reforms for the next ovulatory cycle. It is shown that the female reproductive tract has multiple functions that must occur in sequence. The coevolution of the embryo and maternal tract thus led to the close contact of two genetically different tissues, and problems such as the inflammatory reaction had to be overcome. Menstruation is a necessary consequence of these evolutionary changes, and needed no adaptive value in order to evolve.     

Correlation between vascular and cellular responses to atrial natriuretic peptide and to sodium nitroprusside

Atrial natriuretic peptide (ANP) and sodium nitroprusside (SNP) increase cGMP in vascular smooth muscle cells and act as vasodilators in some, but not all, blood vessels. In this present study, we attempted to correlate the ability of these two agents to dilate blood vessels with the ability to increase cGMP in cultured vascular smooth muscle cells. In the isolated guinea pig heart, SNP dose-dependently increased coronary flow while ANP was ineffective. In smooth muscle cells cultured from the coronary system, SNP increased intracellular cGMP in a dose-dependent manner while ANP had no effect on cGMP in these cells. In isolated guinea-pig thoracic aorta, precontracted with K+, both ANP and SNP produced relaxation and ANP was the more potent. In smooth muscle cells cultured from the aorta, ANP and SNP increased cGMP and the potency relationship was similar to the intact vessel. These results support the view that phenotypic properties of vascular smooth muscle cells can account for differences in the response of blood vessels to vasodilators.     

On the implementation of bytecode compression for interpreted languages

This paper describes a new method for code space optimization for interpreted languages called LZW‐CC . The method is based on a well‐known and widely used compression algorithm, LZW , which has been adapted to compress executable program code represented as bytecode. Frequently occurring sequences of bytecode instructions are replaced by shorter encodings for newly generated bytecode instructions. The interpreter for the compressed code is modified to recognize and execute those new instructions. When applied to systems where a copy of the interpreter is supplied with each user program, space is saved not only by compressing the program code but also by automatically removing the unused implementation code from the interpreter. The method's implementation within two compiler systems for the programming languages Haskell and Java is described and implementation issues of interest are presented, notably the recalculations of target jumps and the automated tailoring of the interpreter to program code. Applying LZW‐CC to nhc98 Haskell results in bytecode size reduction by up to 15.23% and executable size reduction by up to 11.9%. Java bytecode is reduced by up to 52%. The impact of compression on execution speed is also discussed; the typical speed penalty for Java programs is between 1.8 and 6.6%, while most compressed Haskell executables run faster than the original. Copyright © 2008 John Wiley & Sons, Ltd.     

Molecular structure and driving force to metastable states: Janus faces in polymer crystallization

This paper is a retrospective of a past dedicated to research on polymers and a situation sketch of the present and the near future. (Co)polymers discussed are mainly based on ethylene. (Cross‐)fractionation techniques combined with state‐of‐the‐art characterization techniques, like quantitative differential scanning calorimetry, are powerful tools for the study of the links between two main topics: molecular structure and crystallization/melting. These form the two ‘Janus faces’ polymers can show, namely Face 1: the molecular structure resulting from polymerization with the keyword ‘nature’; and Face 2: the driving force of crystallization towards a metastable state, with the keyword ‘nurture’. After all, to meet demands for properties of products, in principle one starts with a given molecular architecture, after which dedicated processing, including application of temperature–time ramps, has to do the job. With new instrumentation, especially fast scanning (chip) calorimetry, for the first time in history the driving force towards crystallization into one of the possible metastable states – via Face 2 – can be controlled, of course within certain limits given by Face 1. This promising outlook of combining the faces to a useful symbiosis of Janus will be a challenge for those working in the science of crystallization of polymers. © 2018 Society of Chemical Industry     

Scientific Paragon to Hospital Mall: The Evolving Design of the Hospital, 1885–1994

Since 1885, the hospital has evolved from a public charity to a scientific paragon. A growing chorus of criticism, though, attacks its impersonality and inhospitality, especially in the emerging competitive health market which emphasizes ambulatory care. Hospital administrators have responded by asking designers to re-create the hospital into a more welcoming and accessible place. A popular method of achieving comfort and familiarity has been to adapt elements of the shopping mall to the hospital and even to consider merging mall and hospital. This adaptation raises important concerns about the evolution of attitudes toward illness and death, private and public spaces, and the mall as a modern design standard. This article highlights one unusual implication, the possibility that the mall, viewed as a reason for the diminishment of public space, might be a means of opening to the public one of society's most closed institutions—the hospital.     

Determination of total dietary fibre and available carbohydrates: A rapid integrated procedure that simulates in vivo digestion

The new definition of dietary fibre introduced by Codex Alimentarius in 2008 includes resistant starch and the option to include non‐digestible oligosaccharides. Implementation of this definition required new methodology. An integrated total dietary fibre method was evaluated and accepted by AOAC International and AACC International (AOAC Methods 2009.01 and 2011.25; AACC Method 32–45.01 and 32–50.01, and recently adopted by Codex Alimentarius as a Type I Method. However, in application of the method to a diverse range of food samples and particularly food ingredients, some limitations have been identified. One of the ongoing criticisms of this method was that the time of incubation with pancreatic α‐amylase/amyloglucosidase mixture was 16 h, whereas the time for food to transit through the human small intestine was likely to be approximately 4 h. In the current work, we use an incubation time of 4 h, and have evaluated incubation conditions that yield resistant starch and dietary values in line with ileostomy results within this time frame. Problems associated with production, hydrolysis and chromatography of various oligosaccharides have been addressed resulting in a more rapid procedure that is directly applicable to all foods and food ingredients currently available.

     

Painful justice: an ethical perspective on the allocation of trauma services in Australia

Australia faces general and particular problems in the just distribution of trauma services, such as a proliferation of expensive technologies, economic and geographic limitations on their provision, and inequities in allocation. The ethics of shalom in which people live in harmonious relationships with each other, the world and God provide a moral framework for the discussion of the allocation of health care. Ethics deal with people and their relationships, which entails examining the nature and consequences of an action or policy and the character of the persons and institutions involved. The goal of health care, including trauma services, is not to 'fight disease' or to improve the health of the community, but to return people to proper functioning as people-in-relationships, as far as this is practicable. In applying this to the equitable provision of trauma services in Australia, we should distinguish between sustenance rights and community-provided mercies. The former are basic services that we need in order to function meaningfully in the community, and to which we are entitled (eg., basic health care). The latter are other benefits that we as members of the community choose to provide for each other, but to which we are not entitled per se (eg., ICU, Tertiary Trauma Centres). We should do all we reasonably can to ensure that all people receive their healthcare sustenance rights, that healthcare mercies are equitably distributed, and that the person-orientation of health care is maintained in the face of 'technological imperatives'.