cssi/SciSciGPT-SciSciNet huggingface dataset:
Luminescent Charge-Transfer Platinum(II) Metallacycle

The photophysical and electrochemical properties of a platinum(II) diimine complex bearing the bidentate diacetylide ligand tolan-2,2‘-diacetylide (tda), Pt(dbbpy)(tda) [dbbpy = 4,4‘-di-tert-butyl-2,2‘-bipyridine] (1), are compared with two reference compounds, Pt(dbbpy)(C⋮CPh)2 (2) and Pt(dppp)tda [dppp = 1,3-bis(diphenylphosphino)propane] (3), respectively. The X-ray crystal structure of 1 is reported, which illustrates the nearly perfect square planarity exhibited by this metallacycle. Chromophore 2 possesses low-lying charge-transfer excited states analogous to 1, whereas structure 3 lacks such excited states but features a low-lying platinum-perturbed tda intraligand triplet manifold. In CH2Cl2, 1 exhibits a broad emission centered at 562 nm at ambient temperature, similar to 2, but with a higher photoluminescence quantum yield and longer excited-state lifetime. In both instances, the photoluminescence is consistent with triplet-charge-transfer excited-state parentage. The rigidity imposed by the cyc...
Heat capacity studies on single crystal annealed Fe 3 O 4

Single crystals of magnetite were grown and annealed under a controlled oxygen atmosphere to produce homogeneous, single phase samples. Heat capacity studies revealed a single, sharp first order heat capacity transition at the Verwey transition ${T}_{V}$\ensuremath{\simeq}121 K, no anomaly at 10 K, no evidence for short range order, and an entropy of transition of \ensuremath{\Delta}${S}_{v}$=R ln2 per mole of ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$. A model accounting for this numerical result is discussed.
Effect of sodium bisulfite on properties of soybean glycinin

The objective of this work is to understand the function of glycinin in soy protein adhesive formation. Glycinin protein was treated with sodium bisulfite, and physicochemical, morphological, and adhesion properties of the modified soy glycinin were characterized. More disulfide bonds that associated acidic and basic polypeptides of glycinin broke as the sodium bisulfite concentration increased. The reduction of disulfide bonds did not decrease the thermal stability of glycinin. Instead, the denaturation temperature of modified glycinin increased as sodium bisulfite increased. Sodium bisulfite-induced disulfide bond cleavage increased the surface hydrophobicity of modified glycinin. Hydrophobic force is the main driving force for glycinin aggregation, and the balance between hydrophobic and electrostatic forces makes glycinin form chainlike aggregates. The adhesive strength and water resistance of glycinin dropped significantly at lower levels of sodium bisulfite and then increased as the amount of sodium bisulfite increased up to 24 g/L. The adhesive performance decreased again with further addition of sodium bisulfite. The adhesive strength of glycinin was not improved by sodium bisulfite modification in the studied range.
Harmful Medication Errors in Children: A 5-Year Analysis of Data from the USP's MEDMARX® Program

Harmful pediatric medication errors are common in hospitals and health systems. Understanding what products are involved in these errors is important in the prevention of future errors. We used data from a voluntary medication error reporting system (MEDMARX®) and identified 816 harmful outcomes involving 242 medications during a 5-year period. Eleven medications accounted for more than one third of reported errors ( n = 261 or 34.5%). Wrong dosing and omission errors were common and were associated with therapeutic classes such as opioid analgesics (e.g., morphine and fentanyl), antimicrobial agents (e.g., vancomycin and gentamicin), and antidiabetic agents (e.g., insulin). Older commonly used agents still resulted in a substantial number of harmful pediatric medication errors and should be included in the focus of patient safety activities.
Using seabird habitat modeling to inform marine spatial planning in central California's National Marine Sanctuaries.

Understanding seabird habitat preferences is critical to future wildlife conservation and threat mitigation in California. The objective of this study was to investigate drivers of seabird habitat selection within the Gulf of the Farallones and Cordell Bank National Marine Sanctuaries to identify areas for targeted conservation planning. We used seabird abundance data collected by the Applied California Current Ecosystem Studies Program (ACCESS) from 2004–2011. We used zero-inflated negative binomial regression to model species abundance and distribution as a function of near surface ocean water properties, distances to geographic features and oceanographic climate indices to identify patterns in foraging habitat selection. We evaluated seasonal, inter-annual and species-specific variability of at-sea distributions for the five most abundant seabirds nesting on the Farallon Islands: western gull (Larus occidentalis), common murre (Uria aalge), Cassin’s auklet (Ptychorampus aleuticus), rhinoceros auklet (Cerorhinca monocerata) and Brandt’s cormorant (Phalacrocorax penicillatus). The waters in the vicinity of Cordell Bank and the continental shelf east of the Farallon Islands emerged as persistent and highly selected foraging areas across all species. Further, we conducted a spatial prioritization exercise to optimize seabird conservation areas with and without considering impacts of current human activities. We explored three conservation scenarios where 10, 30 and 50 percent of highly selected, species-specific foraging areas would be conserved. We compared and contrasted results in relation to existing marine protected areas (MPAs) and the future alternative energy footprint identified by the California Ocean Uses Atlas. Our results show that the majority of highly selected seabird habitat lies outside of state MPAs where threats from shipping, oil spills, and offshore energy development remain. This analysis accentuates the need for innovative marine spatial planning efforts and provides a foundation on which to build more comprehensive zoning and management in California’s National Marine Sanctuaries.
Box I and II motif from myelin basic protein gene promoter binds to nuclear proteins from rodent brain

The box I and II motif located within the promoter of the myelin basic protein gene contains a simian virus 40 T-antigen-binding site, a MyoD/E2a-binding site, and a glucocorticoid receptor-binding site. We have found proteins within nuclear extracts from adult mouse brain, rat embryonic cerebral cortex in culture, and a mouse oligodendrocyte-like cell line that bind to a 32P-labeled synthetic DNA fragment containing the sequences of the box I and II motif. Three major complexes (A, B, and C) were seen in gel-shift assays. Only complexes A and B were competed out by the unlabeled box I and II fragment or by another synthetic DNA fragment that also contains sequences similar to a glucocorticoid receptor-binding site. Therefore, complexes A and B were thought to be specific. The expression pattern of the proteins responsible for the formation of these complexes was also assessed during development in mouse brain.
Propulsion for the space station

Abstract Propulsion for the Space Station requires a unique, challenging combination of features. The propulsion requirements demand responsive capabilities for orbit control and countering on-board or externally induced forces, and precision control for station-keeping with minimum disturbances. The propulsion design must provide high performance to minimize propellant requirements, have extremely high reliability, provide an extended long-life capability, control emissions and outgasses that could impact in-space operations, and provide maximum safety. Comprehensive evaluations have been performed of numerous design options; these included monopropellants, earth-storable bipropellants, subcritically and supercritically stored cryogenic propellants, use of residual and/or waste fluids, pump-fed and pressure-fed systems, systems with and without gas accumulators, various pressurization methods, and several types of thrusters. The NASA Space Station program office has defined a baseline propulsion system based on hydrogen/oxygen thrusters, using an on-board water electrolysis system to provide the propellants. This system is combined with a low thrust (100 millipound) resistojet propulsion module that can operate using excess or waste fluids. With this combined on-board propulsion system the need to transport propellants to orbit is basically eliminated, as is the need to collect, store, and return waste fluids to earth. Prototype thrusters for the on-board propulsion have been fabricated and tested, with excellent performance and durability demonstrated. Features that enhance long life, maintainability, servicing, and health monitoring have been studied and are being incorporated. A versatile propulsion test bed has been designed and an extensive demonstration program initiated.
Electrodeposition on a moving wire in an overflow cell

Abstract The effect of sweep rate of cathodic potential, wire speed, superimposed fluid flow rate, temperature and concentration of CuSO4 solutions with large excess of H2SO4 was studied on 0·51 mm diameter horizontal copper wire. The limiting current density, IL was found to increase with wire speed. W and ILL is proportional to W0·42 up to 2·5 m/s and to W0·90 up to 40 m/s in the absence of additional fluid flow. IL increased with increasing fluid flow rate especially at low wire speeds (
The effects of race, residence, and prenatal care on the relationship of maternal age to neonatal mortality.

This population-based study explores whether excessive neonatal mortality rates (NMRs) among infants with teenage mothers are attributable to young maternal age or to a translation of environmental disadvantage into reproductive disadvantage. First births from the 1976-79 linked birth and infant death registers for three states are analyzed. The data set is sufficiently large (305,907 births) to measure maternal age in fine gradations while including several control variables in logit analyses. The associations of racial identification and prenatal care with low birthweight, short gestation, and neonatal mortality overshadow and confound the association between teenage and poor outcome. At every maternal age, higher NMRs are observed for Blacks compared to Whites. The hypothesis that excessive neonatal mortality among Blacks is due to the greater frequency of teenage childbearing among Blacks is refuted. Indeed, unlike White, Black primiparae above age 23 experience higher NMRs than most Black or White te...
Effects of Modified Effective Length Models of the Rupture Zone on the Analysis of a Fluid Journal Bearing

Two versions of a model for the thermal behavior of the lubricant film in the cavitation region of a journal bearing are presented and incorporated into a solution algorithm for the operating characteristics of an axially grooved bearing. The model is based on an approximation of the flow as two parts: Couette-like streamers plus uniform velocity portions adhered to the journal. One version (CH) results from assuming a constant ratio between the cavity height and the local gap height. The other (FH), results from assuming a constant thickness of the adhered fluid layer. An approximate energy equation is derived for the rupture zone and applied to the calculation of the bearing wall temperature. Parametric studies of the effects of the choice of cavity dimensions indicate that for appropriate choices the agreement between theory and published experiment is significantly better for the new methods. Agreement is lightly better for the FH model that for the CH model, and because of physical arguments the FH m...
Development of high-definition aqueous polyvinylpyrrolidone photoresists for cathode ray tubes

Aqueous photoresists that are capable of higher resolutions than are currently employed by the cathode ray tube (CRT) industry were developed by combining photoactivators, which activate at shorter UV wavelengths with polyvinylpyrrolidone (PVP). Two photoactivators were synthesized: 4,4′-diazido-2,2′-biphenyl disodium disulfonate (DABP), which has a maximum absorbance at 264 nm, and 4,4′-diazido-2,2′-biphenylethane disodium disulfonate (DABPE), which has a maximum absorbance at 258 nm. The PVP/DABP and PVP/DABPE photoresists successfully imaged a pattern with resolution as small as 4.4 μm with photoactivator concentrations greater than 20% of the PVP concentration. Addition of silane and emulgen greatly improved the performance of the photoresists with more uniform coatings of thicknesses of up to 1.4 μm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1637–1644, 2006
Roads to polyploidy: the megakaryocyte example.

Polyploidy, recognized by multiple copies of the haploid chromosome number, has been described in plants, insects, and in mammalian cells such as, the platelet precursors, the megakaryocytes. Several of these cell types reach high ploidy via a different cell cycle. Megakaryocytes undergo an endomitotic cell cycle, which consists of an S phase interrupted by a gap, during which the cells enter mitosis but skip anaphase B and cytokinesis. Here, we review the mechanisms that lead to this cell cycle and to polyploidy in megakaryocytes, while also comparing them to those described for other systems in which high ploidy is achieved. Overall, polyploidy is associated with an orchestrated change in expression of several genes, of which, some may be a result of high ploidy and hence a determinant of a new cell physiology, while others are inducers of polyploidization. Future studies will aim to further explore these two groups of genes.
Induced pluripotent stem cells: paths to new medicines. A catalyst for disease modelling, drug discovery and regenerative therapy.

Human embryonic stem cells (hESCs) have captured the interest of scientists, the public and the media because of their potential to realize the goal of regenerative medicine, to aid drug discovery and to advance our knowledge about human development and biology. However, practical applications have been slow to come, owing to technical challenges and to the intense ethical and moral debate over the destruction of embryos that has led to legislation prohibiting or seriously curtailing the generation of hESC lines in some countries. Nevertheless, on 21 January 2009, the US Food and Drug Administration (FDA) approved the first Investigational New Drug Application for a therapy based on hESCs to repair spinal cord injury, which was developed by Geron (Menlo Park, CA, USA). Because traditional techniques to generate hESCs use surplus IVF embryos, it is not possible to create patient or disease‐specific stem‐cell lines—a drawback that significantly diminishes their therapeutic usability. The recent breakthrough work of 'reprogramming' human somatic cells to become pluripotent cells has therefore energized the field; in addition, it offers basic researchers and clinical scientists the possibility to generate patient or disease‐specific stem‐cell lines without the legal, regulatory and ethical problems that often go hand‐in‐hand with hESCs. In fact, because these reprogrammed cells are so similar in developmental potential to authentic hESCs, they are able to differentiate into all possible cell types representing all three embryonic germ layers (Takahashi & Yamanaka, 2006; Takahashi et al , 2007; Yu et al , 2007; Park et al , 2008a). They have therefore been named induced pluripotent stem cells (iPSCs). The iPSC technology could become an extremely useful tool for basic research, therapeutic developments and other applications; for example, human stem cells could have a significant impact on drug development and toxicity tests to replace and refine animal experiments and tests. …
Nuclear Binding Sites for Juvenile Hormone and Its Analogs in the Epidermis of the Tobacco Hornworm

Juvenile hormones (JH) are sesquiterpene derivatives that regulate both morphogenetic and reproductive development in insects. The larval epidermis of the tobacco hornworm, Manduca sexta, was found to take up both 3H-JH I and a biologically active JH analog, [125I]iodovinylmethoprenol (IVMA), from the incubation medium with 33% of the label going to the nucleus in both cases. An exchange assay using isolated nuclei showed the presence of two binding sites with approximate KD values of 7 and 88 nM for JH I and 4 and 59 nM for IVMA. There were about 10,000 of the high affinity sites per nucleus. The binding of both hormones was sensitive to pH and Pronase digestion. In competition studies, JH II and JH III competed for 3H-JH I binding sites, whereas IVMA, hydroprene, and methoprene did not. In similar studies, methoprene and hydroprene competed for [125I]IVMA binding sites but JH I, JH II, and JH III were all ineffective. These results are consistent with the presence of specific and distinct binding sites for JH and IVMA in these nuclei.
Experimental Investigations of the Viscoelastic and Damage Behaviors of Hot-Mix Asphalt in Compression

In this paper, the characteristic behaviors of hot-mix asphalt (HMA) in compression are studied by using concepts from the viscoelastic continuum damage (VECD) modeling approach. Temperature and frequency sweep tests with and without confining pressure were performed to determine the linear viscoelastic properties of HMA. The analysis of these tests showed that HMA exhibits significant and reversible stress-hardening behavior. This behavior was subsequently modeled by using a model developed from similar efforts for granular materials. To prove the importance of considering this characteristic behavior, constant crosshead rate tests were performed and analyzed with and without stress hardening. The VECD analysis framework was utilized for this purpose. When stress-hardening behavior was taken into account, it was found that microdamage-induced softening occurred over a range of temperatures from 5°C to 55°C. This finding suggests that microdamage may be significant for conditions in which HMA rutting is a...
Classroom Deliberation in an Era of Political Polarization

From 2005 to 2009, we were engaged in a longitudinal study of high school classes that included deliberations about controversial political issues. The purpose of the study was twofold: to examine ...
Optical coherence tomography and hyperspectral imaging of vascular recovery in a model of peripheral arterial disease

Peripheral arterial disease (PAD) leads to an increased risk of myocardial infarction and stroke, increased mortality, and reduced quality of life. The mouse hind limb ischemia (HLI) model is the most commonly used system for studying the mechanisms of collateral vessel formation and for testing new PAD therapies, but there is a lack of techniques for acquiring physiologically-relevant, quantitative data intravitally in this model. In this work, non-invasive, quantitative optical imaging techniques were applied to the mouse HLI model over a time course. Optical coherence tomography (OCT) imaged changes in blood flow (Doppler OCT) and microvessel morphology (speckle variance OCT) through the skin of haired mice with high resolution. Hyperspectral imaging was also used to quantify blood oxygenation. In ischemic limbs, blood oxygenation in the footpad was substantially reduced after induction of ischemia followed by complete recovery by three weeks, consistent with standard measures. Three dimensional images of the vasculature distal to vessel occlusion acquired with speckle variance OCT revealed changes in OCT flow signal and vessel morphology. Taken together, OCT and hyperspectral imaging enable intravital acquisition of both functional and morphological data which fill critical gaps in understanding structure-function relationships that contribute to recovery in the mouse HLI model. Therefore, these optical imaging methods hold promise as tools for studying the mechanisms of vascular recovery and evaluating novel therapeutic treatments in preclinical studies.
Autonomous security for autonomous systems

The Internet's interdomain routing protocol, BGP, supports a complex network of Autonomous Systems which is vulnerable to a number of potentially crippling attacks. Several promising cryptography-based solutions have been proposed, but their adoption has been hindered by the need for community consensus, cooperation in a public key infrastructure (PKI), and a common security protocol. Rather than force centralized control in a distributed network, this paper examines distributed security methods that are amenable to incremental deployment. Typically, such methods are less comprehensive and not provably secure. The paper describes a distributed anomaly detection and response system that provides comparable security to cryptographic methods and has a more plausible adoption path. Specifically, the paper makes the following contributions: (1) it describes pretty good BGP (PGBGP), whose security is comparable (but not identical) to secure origin BGP; (2) it gives theoretical proofs on the effectiveness of PGBGP; (3) it reports simulation experiments on a snapshot of the Internet topology annotated with the business relationships between neighboring networks; (4) it quantifies the impact that known exploits could have on the Internet; and (5) it determines the minimum number of ASes that would have to adopt a distributed security solution to provide global protection against these exploits. Taken together these results explore the boundary between what can be achieved with provably secure centralized security mechanisms for BGP and more distributed approaches that respect the autonomous nature of the Internet.
Does the first year of teaching have to be a bad one? A case study of success

Abstract During the past two decades, researchers have shown considerable interest in teachers engaged in their first year of employment, a career phase believed to have long-term implications for teaching effectiveness, job satisfaction, and career length. One result of this line of inquiry is an extensive set of case studies describing failure in first-year teaching. However, there are occasional reports of positive examples of teacher induction, and close examination of new teachers who succeed has been suggested as an alternative means to understand success and failure in teaching. The study reported here is a case study of success in first-year teaching. Based on observations and interviews conducted over the course of one academic year, it focuses on the descriptions and interpretations of a new physical education teacher at a public school in the United States. The results revealed several factors which impacted the success of the first-year teacher studied, some related to preservice teacher preparation, others to school context, and others a result of taking an active role in the school social context. Three major themes evolved: (a) a match between expectations, personality, and workplace realities; (b) evidence of impact; and (c) using successful strategies to manage student behavior and enter the social and political culture of the school. The findings draw attention to the interplay between personal background, experiences during teacher preparation, and workplace characteristics as influences of not only relative success in teaching, but also a teacher's perceptions and interpretations of her school, students, and teaching performance.
The Role of Culture in Parents' Socialization of Children's Emotional Development

Parents’ emotion coaching of children and modeling of effective emotional responses are associated with children’s positive emotional development. However, much of the research in this area has been with European American families. This study examined parents’ self-reports about their emotion regulation patterns and coaching their children about emotions, across three racial and ethnic groups (African American, European American, and Multiracial), to determine how well these parental behaviors predicted their children’s self-reports of depressive and anxiety symptoms 18 to 24 months later (N = 99). For the African American families, a higher level of coaching about anger and sadness by mothers was linked with lower depressive symptoms in their children. A higher level of anger coaching by fathers within the Multiracial group was also associated with lower anxiety and depressive symptoms. This study supports the importance of cultural values, within racial and ethnic groups, in parenting approaches associa...
Six intermediate-mass stars with far-infrared excess: a search for evolutionary connections

ABSTRA C T We present the results of high-resolution spectroscopic, low-resolution spectrophotometric and spectropolarimetric and broad-band multicolour observations of four B-type stars (HD 4881, 5839, 224648 and 179218) and two A-type stars (HD 32509 and 184761) with strong far-infrared (IR) excesses. The excess in HD 184761, which is located at a distance of 65 pc from the Sun, was recognized for the first time. Double-peaked Ha emission line profiles are found in HD 4881 and HD 5839, while HD 184761, HD 224648 and HD 32509 display no emission in Ha. The remarkable variations observed in the Ha profile of HD 179218 are also observed in some classical Be and Herbig Ae/Be stars. An intrinsic component of polarization is clearly present in HD 179218, only an interstellar component is detected in HD 4881 and HD 224648, and HD 184761 was found to be unpolarized. Improved effective temperatures for all six objects were derived. Parallaxes measured by the Hipparcos satellite were used to determine positions of the stars in the HR diagram. HD 4881 and HD 5839 are an order of magnitude more luminous than main-sequence stars of similar temperatures and are most likely newly discovered classical Be stars. Study of the high-resolution IRAS maps and modelling of the spectral energy distributions of HD 4881, HD 5839 and HD 224648 suggest that the observed large IR excesses are caused by radiation from circumstellar dust rather than free‐free radiation or infrared cirrus, so they may be higher mass counterparts of b Pictoris stars. HD 32509, HD 224648 and HD 184761, which have very small near-IR excesses, are probably young main-sequence stars. HD 179218, which exhibits the largest near- and far-IR excess in the sample, is an isolated pre-main-sequence Herbig Be star.
Recent advances in memory consistency models for hardware shared memory systems

The memory consistency model of a shared memory system determines the order in which memory operations will appear to execute to the programmer. The memory consistency model for a system typically involves a tradeoff between performance and programmability. The paper provides an overview of recent advances in hardware optimizations; compiler optimizations, and programming environments relevant to memory consistency models of hardware distributed shared memory systems. We discuss recent hardware and compiler optimizations that exploit the observation that it is sufficient to only appear as if the ordering rules of the consistency model are obeyed. These optimizations substantially improve the performance of the strictest consistency model, making it more attractive for its programmability. Recent concurrent programming languages and environments, on the other hand, support more relaxed consistency models. We discuss several such environments, including POSIX threads, Java, and OpenMP.
Parameter estimation for MRF stereo

This paper presents a novel approach for estimating parameters for MRF-based stereo algorithms. This approach is based on a new formulation of stereo as a maximum a posterior (MAP) problem, in which both a disparity map and MRF parameters are estimated from the stereo pair itself. We present an iterative algorithm for the MAP estimation that alternates between estimating the parameters while fixing the disparity map and estimating the disparity map while fixing the parameters. The estimated parameters include robust truncation thresholds, for both data and neighborhood terms, as well as a regularization weight. The regularization weight can be either a constant for the whole image, or spatially-varying, depending on local intensity gradients. In the latter case, the weights for intensity gradients are also estimated. Experiments indicate that our approach, as a wrapper for existing stereo algorithms, moves a baseline belief propagation stereo algorithm up six slots in the middlebury rankings.
Spatial and multidimensional visualization of Indonesia's village health statistics

A community health assessment (CHA) is used to identify and address health issues in a given population. Effective CHA requires timely and comprehensive information from a wide variety of sources, such as: socio-economic data, disease surveillance, healthcare utilization, environmental data, and health resource allocation. Indonesia is a developing country with 235 million inhabitants over 13,000 islands. There are significant barriers to conducting CHA in developing countries like Indonesia, such as the high cost of computing resources and the lack of computing skills necessary to support such an assessment. At the University of Pittsburgh, we have developed the Spatial OLAP (On-Line Analytical Processing) Visualization and Analysis Tool (SOVAT) for performing CHA. SOVAT combines Geographic Information System (GIS) technology along with an advanced multidimensional data warehouse structure to facilitate analysis of large, disparate health, environmental, population, and spatial data. The objective of this paper is to demonstrate the potential of SOVAT for facilitating CHA among developing countries by using health, population, healthcare resources, and spatial data from Indonesia for use in two CHA cases studies. Bureau of Statistics administered data sets from the Indonesian Census, and the Indonesian village statistics, were used in the case studies. The data consisted of: healthcare resources (number of healthcare professionals and facilities), population (census), morbidity and mortality, and spatial (GIS-formatted) information. The data was formatted, combined, and populated into SOVAT for CHA use. Case study 1 involves the distribution of healthcare professionals in Indonesia, while case study 2 involves malaria mortality. Screen shots are shown for both cases. The results for the CHA were retrieved in seconds and presented through the geospatial and numerical SOVAT interface. The case studies show the potential of spatial and multidimensional analysis using SOVAT for community health assessment in developing countries. Since SOVAT is based primarily on open-source components and can be deployed using small personal computers, it is cost-effective for developing countries. Also, combining the strength in analysis and the ease of use makes tools like SOVAT ideal for healthcare professionals without extensive computer skills.
Selective electron beam irradiation of high purity semi-insulating 4H silicon carbide substrates to characterize the effects on photoconductive semiconductor switch operation

High energy electron beam irradiation of bulk SiC creates crystal defects within the material which act as deep traps. These deep traps capture charge carriers and in turn increase the resistivity/blocking voltage of SiC photoconductive semiconductor switches (PCSS). Irradiation has been reported to increase the blocking field of a vertical SiC PCSS to 705 kV/cm when the entire sample region is irradiated with a 1×1018 cm-2 dose from a 1 MeV electron beam1. This paper investigates selectively irradiating specific regions of a SiC PCSS gap to characterize the effects on DC operation. Lateral switches were fabricated on a high-purity semi-insulating 4H-SiC sample and subsequently irradiated to form three sample types of differing irradiation regions. The selectively irradiated regions are: 1) mid-gap, 2) both contact-gap interfaces, and 3) a single gap-contact interface used for both anode and cathode testing configurations depending upon the polarity of the applied voltage.
High speed RLS using scaled tangent rotations (STAR)

The QR decomposition based recursive least-squares (RLS) adaptive filtering algorithm (QRD-RLS) has a processing speed limitation. Fine-grain pipelining of the recursive loops within the cells using look-ahead techniques requires large hardware increase. A new scaled tangent rotation (STAR) is used instead of the usual Givens rotations. The scaled tangent rotation (STAR) RLS algorithm (STAR-RLS) is designed such that fine-grain pipelining can be accomplished very easily. The scaled tangent rotation are not exactly orthogonal transformations but tend to become orthogonal asymptotically. Simulation results show that the algorithm performance is similar to that of the QRD-RLS algorithm. The STAR-RLS algorithm can be mapped onto a systolic array. The computational complexity and inter cell communications are considerably lower than the QRD-RLS algorithm and the square-root free techniques. >
Computer-paced versus experimenter-paced working memory span tasks: Are they equally reliable and valid?☆

article i nfo Working memory span tasks are popular measures, in part, because performance on these tasks predicts per- formance on other measures of cognitive ability. The traditional method of span-task administration is the experimenter-paced version, whose reliability and validity have been repeatedly demonstrated. However, computer-paced span tasks are becoming increasingly more popular. Despite their popularity, no study had sys- tematicallycomparedexperimenter-pacedandcomputer-pacedversionsof thereadingspanandoperationspan tasks. Such a comparison is important because research labs in many universities across many countries admin- ister these span tasks with a variety of methods. The purpose of the present study was to evaluate the reliability and validity of computer-paced span tasks and to compare these estimates to those of experimenter-paced span tasks. Results indicated that experimenter-paced and computer-paced span tasks share some overlap, but also measure additional and distinct processes. Computer-paced span tasks were highly reliable measures as well as valid indicators of fluid intelligence (Gf). Thus, computer-paced span tasks may be the optimal type of admin- istration given their methodological advantages over experimenter-paced span tasks.
The Role of Methane in the Global Environment

The increasing concentration of methane (CH4) in the atmosphere is of concern because of the potential effects that it can have on global atmospheric chemistry and climate. Due to its relatively long atmospheric lifetime, methane emissions do not have an appreciable effect on local or regional air pollution. However, methane chemistry does have an important influence on the global atmosphere, affecting the amount of ozone (O3) in both the troposphere and stratosphere, the amount of hydroxyl (OH) in the troposphere, and the amount of water vapor (H2O) in the stratosphere. The oxidation of methane is an important source of atmospheric carbon monoxide (CO) and formaldehyde (CH2O). Methane is the most abundant reactive trace gas in the troposphere. In addition, methane is a greenhouse gas, and its increasing concentrations are of interest to concerns about climate change.
The Debt Trap: Wealth Transfers and Debt-Equity Choices of Junk-Grade Firms

If outstanding debt is risky, issuing equity transfers wealth from equity holders to debt holders. If existing leverage is high and bankruptcy costs are small, this wealth transfer effect outweighs the gains to stockholders from optimizing firm value. Empirically, we find that for investment-grade firms, higher leverage implies a greater likelihood of issuing equity, as expected in a standard tradeoff model. However, consistent with the impact of wealth transfer effects, for junk-grade firms, higher leverage implies a greater likelihood of issuing debt. The analysis implies an additional route through which historical shocks determine firms’ financing choices.
Dynamic whole-body 68Ga-DOTATOC PET/CT

648 Objectives 68Ga-DOTATOC PET/CT has established an important role for imaging neuroendocrine tumors (NET) and dynamic PET has been proposed as the preferred acquisition mode (Velikyan 2014). Metastatic NETs can be large and often extend well beyond the axial range of a single PET bed position. We assessed the feasibility of dynamic whole-body (WB) 68Ga-DOTATOC PET/CT which involves the acquisition of dynamic PET data over an extended axial range. Methods Our dynamic WB PET/CT protocol involved WB (eyes to mid-thigh) low-dose CT; 68Ga-DOTATOC injection simultaneous with the start of a 6 min, single-bed, dynamic PET over the heart; immediately followed by 8 sequential WB PET scans (8 × 7 bed positions × 1.5 min / bed). 4 patients with metastatic NETs were studied. For each patient the above imaging protocol was repeated within 4 days. The second study was performed following administration of unlabeled octreotide to assess its effect on tracer distribution. Results Cancer burden was extensive with one tumor measuring 32 cm in the axial direction. Tumor time-activity curves increased throughout the ~90 min imaging period. Tumor SUVs were generally high (SUV 10-60) and very consistent between the repeated studies on the same patient (mean absolute difference 5.7 ± 4.9 % when comparing SUV at last WB pass). Uptake in the spleen was reduced following unlabeled octreotide (mean SUV difference -39.2 ± 25.0 %), with implications for radionuclide therapy. In one patient the extended scan range enabled by the dynamic WB technique revealed unexpected metastases in the thoracic vertebrae. The initial dynamic series over the heart and negligible myocardial uptake in the WB images suggests potential for non-invasive image-derived input function determination, although this capability needs to be carefully validated. Conclusions A dynamic WB PET/CT protocol provides valuable kinetic information over an extended scan range and is ideally suited for use with 68Ga-labelled somatostatin analogs.
Fixing Email

Columnist Charles Day describes some possible solutions for dealing with the daily email deluge.
A calibration-free approach for measuring fracture aperture distributions using X-ray computed tomography

Various methods have been proposed to measure fracture aperture distributions, including X-ray computed tomography (CT) imaging, which has the advantage that it can be combined with dynamic flow experiments. In this paper, we present a calibration-free missing CT attenuation (CFMA) imaging method for measuring fracture apertures that avoids time-consuming calibration. In addition, this model does not assume a homogeneous matrix and thus provides a good estimate of fracture apertures even when rock properties are heterogeneous. The validity of the CFMA model is established by four approaches: comparing apertures calculated with the conventional calibration-based method; evaluating model predictability at different scanner voxel sizes; comparing with calibration coefficients in the literature from a number of experiments with different rocks and X-ray scanners; and comparing aperture measurements for dry and wet scans. We analyze the systematic error and the random error introduced by rock heterogeneities and CT scanning and show that by averaging 5 replicate scans, we reduce the aperture measurement error to ∼22 µm.
Cross-protection between Venezuelan equine encephalomyelitis and eastern equine encephalomyelitis virus.

SummaryMice were capable of with standing a large challenge dose of virulent Venezuelan equine encephalomyelitis virus and a substantial challenge dose of eastern equine encephalomyelitis virus after immunization with an attenuated 9t strain of VEE virus. This resistance was elicited after administration of the 9t strain by the intraperitoneal, subcutaneous, and respiratory routes, the latter being accomplished by short exposures to aerosols of the attenuated strain. Rabbits and guinea pigs, which were refractory to infections with EEE virus, were protected against lethal doses of the heterologous virulent VEE virus.
Synthesis and Characterization of Chitosan-Mg-Based Composite Scaffolds for Bone Repair Applications

Bone has a remarkable ability to regenerate and heal itself when damaged. Most minor injuries heal naturally over time, but when the defects are larger, they require a substrate to support the cell growth and guide the repair process. Bone grafting is currently done by using either an autograft, where the substrate is harvested from a suitable donor site within the patient’s body; or an allograft, where the substrate is harvested from a cadaver. However, both techniques have significant drawbacks. In autografting, significant complications tend to arise from donor site morbidity. In allografting, the issues are the risk of disease transmission, and the logistical difficulties in the local or even global matching process for donor tissue. A third approach, employing tissue-engineered scaffold materials, provides superior performance by helping to restore bone tissue functions during regeneration and by subsequent resorption of the graft material as new bone tissue forms. These bioactive scaffolds are porous and made of natural materials that are capable of harboring growth factors, drugs, genes, or stem cells. The objectives of this research are to synthesize biofunctional composite scaffold materials, based on chitosan (CS) and magnesium (Mg), for use in bone regeneration and to measure their physiochemical properties. Scaffolds were fabricated from the aqueous dispersions of starting materials by subsequent freezing and phase separation by the lyophilization process. A CS solution was prepared by dissolving CS in 2 % (v/v) acetic acid solution, whereas carboxymethyl chitosan (CMC) was dissolved in deionized water. The concentrations of CS and CMC (in a constant 1:1 weight ratio) ranged between 2% and 5 %. Various dry weight percentages of Mg gluconate (MgG) were added to the scaffolds by dissolving the MgG solution in the CS/CMC. SEM imaging showed the scaffolds to possess uniform porosity with a pore size distribution range of 100–150 μm. Micro CT analysis showed that the pores were distributed throughout the scaffold’s entire volume and they were highly interconnected. Compressive strengths of up to 340 kPa and compressive moduli of up to 5 MPa were obtained for these fabricated scaffolds. When introduced into a cell culture medium, these scaffolds were found to remain intact, retaining their original three-dimensional frameworks and ordered porous structures maintaining sufficient mechanical strength. These observations provide a new effective approach for preparing scaffold materials suitable for bone tissue engineering.Copyright © 2015 by ASME
Functional Stem Cell Biomechanics: Application of Biophysical Techniques and Multi-content 3D Image Analysis

The mechanical properties of the cell - cytoskeleton elasticity, membrane tension, and adhesion strength - play an important role in the regulation of stem cell differentiation. While the cellular mechanical properties are significantly altered during stem cell specification to a particular phenotype, the complexity of events associated with transformation of these precursor cells leaves many questions unanswered about morphological, structural, proteomic, and functional changes in differentiating stem cells. However, control of cell behaviors might be feasible through manipulation of the cellular mechanical properties using external physical stimuli and manipulation of mechanically sensitive signaling molecules. Biomechanical regulation of stem cell differentiation can minimize the number of chemicals and growth factors that would otherwise be required for tissue engineering. Coupled with a thorough understanding of stem cell behavior, both experimentally and computationally, development of more effective approaches is a feasible way to expand stem cells and to regulate their phenotypic commitment. We recently developed a high-content/high-throughput screening algorithm that offers significant improvements in 3D quantitative analysis at the single cell level. A consistent pattern observed in all types of stem cell differentiation indicates the cytoskeleton remodeled significantly before lineage-specific cellular changes occurred. This demonstrates that cellular mechanical transformations are a precursor to stem cell differentiation and to phenotypic functionality.
Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome, is the leading cause of chronic liver disease. Treatments target lifestyle modification and improvement of underlying risk factors. Noninvasive biomarkers for diagnosis and staging of NAFLD and safe, cost-effective treatments for patients with nonalcoholic steatohepatitis (NASH) and/or NASH-related cirrhosis are currently under investigation.
Restenosis rate after percutaneous transluminal coronary angioplasty: a literature overview.

In order to elucidate factors affecting the rate of angioplasty restenosis, we reviewed 212 published reports on restenosis after percutaneous transluminal coronary angioplasty. We used five specific methodologic standards to select the 31 reports most likely to produce unbiased results. Sixty one factors judged to be related to restenosis rate were investigated. Only shorter duration of data collection (p=0.0003) was related to higher restenosis rate. This factor may be related to inexperience in choosing subjects or performing procedures. Other factors whose association with restenosis rate did not reach our predetermined level of statistical significance (p less than .01) were angioplasties of the left circumflex artery (p=.02), angioplasty of total occlusions (p=.02) and advanced age (p=.05). The association of shorter data collection with higher restenosis rates suggests that improved outcome may result from consolidation to a few centers specializing in this technique.
Old English Meter

(1990). Old English Meter. ANQ: A Quarterly Journal of Short Articles, Notes and Reviews: Vol. 3, No. 2, pp. 69-74.
Recent Developments in the Nitroxide-Catalyzed Oxidation of Amines: Preparation of Imines and Nitriles

This Concept highlights the discovery and developments in the oxidations of amines catalyzed by TEMPO (2,2,6,6-tetramethylpiperidinyl-N-oxyl) and related catalytic systems. The most important feature of these systems is that, with slight modifications in the reaction media, amines are selectively oxidized to either an imine or nitrile. Progress made toward the oxidation of various benzylic, allylic, and aliphatic amines and possible reaction mechanism pathways are discussed.