Thermoelectric power measurements of wide band gap semiconducting nanowires

We investigated the temperature-dependent thermoelectric power (TEP) of individual wide band gap ZnO and GaN semiconducting nanowires by fabricating the devices with good Ohmic contacts. In the temperature range of 10-300 K, the measured TEP of both nanowires was linearly dependent on temperature, indicating the degenerate doping nature of these nanowires. The room temperature TEP value of ZnO nanowires was as high as -400 mu V/K while an order of magnitude smaller TEP value was observed in GaN. The negative sign of TEP values shows that electrons are the majority carriers in these wide band gap nanowires. More importantly, in comparison with gate-dependent transport measurements of the nanowire field effect transistors, analysis of temperature-dependent TEP measurements provides a reliable way of estimating the majority carrier concentration of nanowires, where conventional Hall effect measurements cannot be used.open116075sciescopu

Phase-Boundary of several Multicube Superconducting Circuits in a Magnetic-Field of Arbitrary Magnitude and Direction

Journals published by the American Physical Society can be found at http://journals.aps.org/A previous study [C.-R. Hu and C.-H. Huang, Phys. Rev. B 43, 7718 (1991)] of the phase boundary T(c)(H) of a single-cube superconducting circuit in an external magnetic field H of arbitrary magnitude and direction is extended here to superconducting circuits containing 2 X 2 X 2, 4 X 4 X 4, and 6 X 6 X 6 cubes. For the last two cases, the study reported here is limited to the vicinity of one major peak of T(c)(H) only, in order to limit the total computing time. However, by going up to 6 X 6 X 6 cubes, we have practically obtained the limiting behavior, in the vicinity of this major peak studied, of an n X n X n cube circuit as n --> infinity. This result is believed to illustrate the generic behavior of all such major peaks, which, as has been noted in the earlier work of Hu and Huang, is the most important property of such circuits for most applicational purposes

Regulation of the pehA gene encoding the major polygalacturonase of Xanthomonas campestris by CIp and RpfF

[[abstract]]Exopolysaccharide and several extracellular enzymes of Xanthomonas campestris pv. campestris (Xcc), the causative agent of black rot in crucifers, are virulence factors. In this study, sequence and mutational analysis has demonstrated that Xcc pehA encodes the major polygalacturonase, a member of family 28 of the glycosyl hydrolases. Using the 5' RACE (rapid amplification of cDNA ends) method, the pehA transcription initiation site was mapped at 102 nt downstream of a CIp (cAMP receptor protein-like protein)-binding site. Transcriptional fusion assays showed that pehA transcription is greatly induced by polygalacturonic acid, positively regulated by CIp and RpfF (an enoyl-CoA hydratase homologue which is required for the synthesis of cis-11-methyl-2-dodecenoic acid, a low-molecular-mass diffusible signal factor), subjected to catabolite repression, which is independent of CIp or RpfF, and repressed under conditions of oxygen limitation or nitrogen starvation. Our findings extend previous work on CIp and RpfF regulation to show that they both influence the expression of pehA in Xcc

Factors considered by undergraduate medical students when selecting specialty of their future careers

Introduction: medical students are the source of a country's physicians. Determining how medical students select their areas of specialization isthe key to achieve a balanced distribution of doctors among all specialties. The objective is to identify the number of medical students who havedecided their postgraduate specialty career, their career specialties preference, and factors that may influence their decision to select a particular specialty.Methods: a facility based cross-sectional study was conducted in  September 2013 at Faculty of Medicine, University of Medical Sciences and Technology, Khartoum, Sudan. A self-administered semi-structured  questionnaire comprising demographic data and questions about future specialties preferences and factors influencing those preferences was  distributed to 887 male and female students, (from first to fifth academicyears) recruited in the study.Results: response rate was 73% with 647 questionnaires collected, out of 887 eligible medical students. Of the returned questionnaires, 604 were valid. The majority of students (541, 89.6%) have chosen a specialty. Surgery, medicine, paediatrics and obstetrics and gynecology were the most selected specialties. The least selected specialty was  anaesthesiology. A significant association was found between gender and specialty choice using Chi-square test (p=0.00). There was no association between undergraduate level and specialty choice (p=0.633). The most common reason for choosing a specific specialty was "Personal Interest" (215, 39.7 %) followed by being "Helpful to the community" (144, 26.6%). Conclusion: surgery, medicine, paediatrics and obstetrics and gynecology were the most selected specialties

Fast empirical Bayesian LASSO for multiple quantitative trait locus mapping

<p>Abstract</p> <p>Background</p> <p>The Bayesian shrinkage technique has been applied to multiple quantitative trait loci (QTLs) mapping to estimate the genetic effects of QTLs on quantitative traits from a very large set of possible effects including the main and epistatic effects of QTLs. Although the recently developed empirical Bayes (EB) method significantly reduced computation comparing with the fully Bayesian approach, its speed and accuracy are limited by the fact that numerical optimization is required to estimate the variance components in the QTL model.</p> <p>Results</p> <p>We developed a fast empirical Bayesian LASSO (EBLASSO) method for multiple QTL mapping. The fact that the EBLASSO can estimate the variance components in a closed form along with other algorithmic techniques render the EBLASSO method more efficient and accurate. Comparing with the EB method, our simulation study demonstrated that the EBLASSO method could substantially improve the computational speed and detect more QTL effects without increasing the false positive rate. Particularly, the EBLASSO algorithm running on a personal computer could easily handle a linear QTL model with more than 100,000 variables in our simulation study. Real data analysis also demonstrated that the EBLASSO method detected more reasonable effects than the EB method. Comparing with the LASSO, our simulation showed that the current version of the EBLASSO implemented in Matlab had similar speed as the LASSO implemented in Fortran, and that the EBLASSO detected the same number of true effects as the LASSO but a much smaller number of false positive effects.</p> <p>Conclusions</p> <p>The EBLASSO method can handle a large number of effects possibly including both the main and epistatic QTL effects, environmental effects and the effects of gene-environment interactions. It will be a very useful tool for multiple QTL mapping.</p

Obstetric professionals’ perceptions of non-invasive prenatal testing for Down syndrome: clinical usefulness compared with existing tests and ethical implications

Background: While non-invasive prenatal testing (NIPT) for fetal aneuploidy is commercially available in many countries, little is known about how obstetric professionals in non-Western populations perceive the clinical usefulness of NIPT in comparison with existing first-trimester combined screening (FTS) for Down syndrome (DS) or invasive prenatal diagnosis (IPD), or perceptions of their ethical concerns arising from the use of NIPT. Methods: A cross-sectional survey among 327 obstetric professionals (237 midwives, 90 obstetricians) in Hong Kong. Results: Compared to FTS, NIPT was believed to: provide more psychological benefits and enable earlier consideration of termination of pregnancy. Compared to IPD, NIPT was believed to: provide less psychological stress for high-risk women and more psychological assurance for low-risk women, and offer an advantage to detect chromosomal abnormalities earlier. Significant differences in perceived clinical usefulness were found by profession and healthcare sector: (1) obstetricians reported more certain views towards the usefulness of NIPT than midwives and (2) professionals in the public sector perceived less usefulness of NIPT than the private sector. Beliefs about earlier detection of DS using NIPT were associated with ethical concerns about increasing abortion. Participants believing that NIPT provided psychological assurance among low-risk women were less likely to be concerned about ethical issues relating to informed decision-making and pre-test consultation for NIPT. Conclusions: Our findings suggest the need for political debate initially on how to ensure pregnant women accessing public services are informed about commercially available more advanced technology, but also on the potential implementation of NIPT within public services to improve access and equity to DS screening services

Iron content in forage sorghum (Sorghum bicolor (L.) Moench) measured on different slit widths with atomic absorption spectrometry

Our objective was to know the right slit width for iron (Fe) concentration of forage sorghum, sorghum hybrid (Sorghum bicolor (L.) Moench), and also to discern which water treatment sludge (WTS) were good for ruminant's health with the feeding sorghum on the present study. The present experiment was carried out on a randomized block design with four treatments; Control, alum sludge compost, alum sludge + NPK (nitrogen, phosphorus, potassium fertilizers), alum sludge compost + NPK (nitrogen, phosphorus, potassium fertilizers). Sorghum hybrid was harvested, and iron content of it was analyzed with an atomic absorption spectrophotometer on background correction (BGC) mode. In order to analyze the iron (Fe) content of the sorghum with the spectrophotometer, three different slit widths conditions were used; 0.15, 0.20 and 0.25 nm. Absorbance and background values were obtained during the Fe analyses with the apparatus. When the background value is small, it is preferred for some trace metals’ analyses. Both (AM/BS) ratio (mean of the absorbance values&lt;AM&gt; to the standard deviation of back ground values&lt;BS&gt;) and (AS&lt;standard deviation of the absorbance values&gt;/BS) ratio, were larger on 0.25 nm slit than those on 0.15 and 0.20 nm slit, and, from our experiment, the condition seemed better on the 0.25 nm slit for the iron analysis with the spectrophotometer. Therefore, the sorghum hybrid grown on (Alum+NPK) and on (Compost only) might be dangerous for ruminants because of their higher values than 200 mg Fe/kg DM (dry matter).Key words: Absorbance, alum sludge, atomic absorption spectrophotometer, background, forage sorghum hybrid, iron, slit

Architecture of Pol II(G) and molecular mechanism of transcription regulation by Gdown1.

Tight binding of Gdown1 represses RNA polymerase II (Pol II) function in a manner that is reversed by Mediator, but the structural basis of these processes is unclear. Although Gdown1 is intrinsically disordered, its Pol II interacting domains were localized and shown to occlude transcription factor IIF (TFIIF) and transcription factor IIB (TFIIB) binding by perfect positioning on their Pol II interaction sites. Robust binding of Gdown1 to Pol II is established by cooperative interactions of a strong Pol II binding region and two weaker binding modulatory regions, thus providing a mechanism both for tight Pol II binding and transcription inhibition and for its reversal. In support of a physiological function for Gdown1 in transcription repression, Gdown1 co-localizes with Pol II in transcriptionally silent nuclei of early Drosophila embryos but re-localizes to the cytoplasm during zygotic genome activation. Our study reveals a self-inactivation through Gdown1 binding as a unique mode of repression in Pol II function

The Effects of Cocaine on Different Redox Forms of Cysteine and Homocysteine, and on Labile, Reduced Sulfur in the Rat Plasma Following Active versus Passive Drug Injections

Received: 28 November 2012 / Revised: 19 April 2013 / Accepted: 6 May 2013 / Published online: 16 May 2013 The Author(s) 2013. This article is published with open access at Springerlink.comThe aim of the present studies was to evaluate cocaine-induced changes in the concentrations of different redox forms of cysteine (Cys) and homocysteine (Hcy), and products of anaerobic Cys metabolism, i.e., labile, reduced sulfur (LS) in the rat plasma. The above-mentioned parameters were determined after i.p. acute and subchronic cocaine treatment as well as following i.v. cocaine self-administration using the yoked procedure. Additionally, Cys, Hcy, and LS levels were measured during the 10-day extinction training in rats that underwent i.v. cocaine administration. Acute i.p. cocaine treatment increased the total and protein-bound Hcy contents, decreased LS, and did not change the concentrations of Cys fractions in the rat plasma. In turn, subchronic i.p. cocaine administration significantly increased free Hcy and lowered the total and protein-bound Cys concentrations while LS level was unchanged. Cocaine self-administration enhanced the total and protein-bound Hcy levels, decreased LS content, and did not affect the Cys fractions. On the other hand, yoked cocaine infusions did not alter the concentration of Hcy fractions while decreased the total and protein-bound Cys and LS content. This extinction training resulted in the lack of changes in the examined parameters in rats with a history of cocaine self-administration while in the yoked cocaine group an increase in the plasma free Cys fraction and LS was seen. Our results demonstrate for the first time that cocaine does evoke significant changes in homeostasis of thiol amino acids Cys and Hcy, and in some products of anaerobic Cys metabolism, which are dependent on the way of cocaine administration