bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic diversity and adaptive variations under static and dynamic management: a case of rice landraces from parts of Odisha in India
Authors: Logapriyan M. , Bisht I. S. , Bhat K. V. , Pani D.
Published: October 2013

In the present study, inter- and intrapopulation diversity of five named rice landraces from parts of Odisha state of India representing static and dynamic management was examined using 14 sequence-tagged microsatellite site primer pairs. A total of 64 alleles were detected in ten populations of the five named landraces. The number of alleles ranged from 2 to 7, with an average of 4.57 alleles per locus. Of the 64 alleles, 60 were common and four were rare. Moderate-to-low diversity was observed in the landrace populations, with the number of alleles per population ranging from 16 to 25 and the percentage of polymorphism ranging from 14.29 to 64.29, respectively. The analysis of molecular variance indicated a highest variation of 75.7% among populations within groups (staticvs.dynamic). The pairwise estimates ofFSTrevealed very high significant population differentiation, which ranged from 0.68 to 0.89, indicating that the populations share limited genetic diversity among them. However, not many variations were observed in the phenotypes of populations representing static and dynamic management. This shows that adaptations of a population apparently persist over generations, but the underlying genotypes change and new alleles or combinations may arise and increase in frequency at the expense of other alleles that have disappeared. The importance of population biology research forin situconservation requires both descriptive and hypothesis testing to guide technical improvement and management of landrace populations.
A Failure to Prohibit: New York City's Underground Bob Veal Trade
Authors: Specht Joshua
Published: October 2013

During the Progressive Era, bob veal, the meat of calves slaughtered at younger than four weeks of age, was incorrectly believed to be poisonous, and its sale was prohibited in areas across the United States. Yet a thriving underground trade persisted. This article studies bob veal's prohibition in Progressive Era New York City to understand where the meat was coming from, how it reached diners' tables, and who was eating it. I argue that bob veal's consumers, many of whom were recent immigrants and the urban poor, recognized the meat was benign. In examining the prohibition's failure, this article studies the politics of regulation and policing. For the ban's advocates, the language and assumptions of the broader pure food and public health movements were simultaneously empowering and constraining, giving reformers a political language to build institutional support for the prohibition and helping journalists sell newspapers even as this language required effacing the complexity of the bob veal trade. From the perspective of bob veal's many producers, smugglers, and consumers, this article highlights how a diffuse social power—a politics on the ground—can trump formal authority.
The Disastrous First Fund-Raising Campaign in Legal Education: The Harvard Law School Centennial, 1914–1920
Authors: Kimball Bruce A.
Published: October 2013

Between 1915 and 1925, Harvard University conducted the first national public fund-raising campaign in higher education in the United States. At the same time, Harvard Law School attempted the first such effort in legal education. The law school organized its effort independently, in conjunction with its centennial in 1917. The university campaign succeeded magnificently by all accounts; the law school failed miserably. Though perfectly positioned for this new venture, Harvard Law School raised scarcely a quarter of its goal from merely 2 percent of its alumni. This essay presents the first account of this campaign and argues that its failure was rooted in longstanding cultural and professional objections that many of the school's alumni shared: law students and law schools neither need nor deserve benefactions, and such gifts worsen the overcrowding of the bar. Due to these objections, lethargy, apathy, and pessimism suffused the campaign. These factors weakened the leadership of the alumni association, the dean, and the president, leading to inept management, wasted time, and an unlikely strategy that was pursued ineffectively. All this doomed the campaign, particularly given the tragic interruptions of the dean's suicide and World War I, along with competition from the well-run campaigns for the University and for disaster relief due to the war.
Long bone histology indicates sympatric species ofDimetrodon(Lower Permian, Sphenacodontidae)
Authors: Shelton Christen D. , Sander P. Martin , Stein Koen , Winkelhorst Herman
Published: October 2013

The Briar Creek Bonebed (Artinskian, Nocona Formation) in Archer County is one of the richest sources ofDimetrodonbones in the Lower Permian of Texas, USA. Based on size, a small (D.natalis), an intermediate (D. booneorum), and a large species (D. limbatus) have been described from this locality. It has been proposed that these traditionally recognised species represent an ontogenetic series of only one species. However, the ontogenetic series hypothesis is inconsistent with the late ontogenetic state of the small bones, as suggested by their osteology and degree of ossification. Histological analysis of newly excavated material from the Briar Creek Bonebed has resolved some of the discretion between these two competing hypothesis, confirming the coexistence of a small (D. natalis) with at least one largerDimetrodonspecies. An external fundamental system is present in the largest sampled long bones identified asD. natalis. The histology ofD. natalispostcrania is described as incipient fibro lamellar bone. This tissue is a combination of parallel-fibred and woven-fibred bone that is highly vascularised by incipient primary osteons. The species status ofD. booneorumandD. limbatusremain unresolved.
«Es ist nicht mehr das alte Leben, das wir führen …» – Beratung von Angehörigen im pflegerischen
Authors: Langer Juliane , Ewers Michael
Published: October 2013

Seit 2012 ist das Entlassungsmanagement in Deutschland gesetzlich vorgeschriebener Teil der Krankenhausbehandlung, um Versorgungskontinuität zu gewährleisten sowie Patient(inn)en und Angehörige beim kritischen Übergang vom Krankenhaus in die ambulante Weiterversorgung zu unterstützen. Offen ist weitgehend, wie die darin integrierte Informationen und Beratung von Angehörigen Pflegebedürftiger konzeptualisiert werden kann. Durchgeführt wurde eine explorative Befragung pflegender Angehöriger in Form von Gruppendiskussionen mit dem Ziel, ihre Erfahrungen und Sichtweisen für eine bedarfsgerechte Gestaltung der Information und Beratung im Entlassungsmanagement zu erheben und nutzbar zu machen. Die Ergebnisse bieten Hinweise auf den aus Sicht der Befragten günstigen Zeitpunkt der Information und Beratung und auf die Bedeutung von Vertrauen für die Angebote, die möglichst weit über die Grenzen des Krankenhauses hinausreichen sollten. Neben krankheits- und pflegebezogenen, organisatorischen und bürokratischen Aspekten war den Angehörigen an emotionaler Auseinandersetzung, Problemlösung und Belastungsreduktion sowie Peerunterstützung im Alltag gelegen. Angehörige in die Konzeptentwicklung für das Entlassungsmanagement einzubinden ist hilfreich, um die Informations- und Beratungsangebote bedarfsgerecht ausrichten zu können.
Sténose œsophagienne non-néoplasique: pas toujours si bénigne
Authors: Lorenz Julie , Vollenweider Peter , Vuilleumier Henri , Schwab Marcos
Published: October 2013

Die ösophageale intramurale Pseudodivertikulose ist selten und ihre Ätiologie ungeklärt, doch sind mit ihr häufig drei Entitäten assoziiert: die gastroösophageale Refluxkrankheit, die ösophageale Candidose und die alkoholische Ösophagitis. Mit konservativer Therapie ist der Verlauf dieser Pathologien weitgehend gutartig. Schwere Fälle, die auf die konservative Therapie nicht ansprechen, können jedoch eine aggressivere Behandlung notwendig machen. Wir präsentieren einen Fall eines Patienten mit einer schweren Ösophagitis, kompliziert durch eine chronische Mediastinitis mit lebensbedrohlichen Auswirkungen, der als Therapie eine Ösophegektomie brauchte.
Asymmetric dimethylarginine attenuates serum starvation-induced apoptosis via suppression of the Fas (APO-1/CD95)/JNK (SAPK) pathway
Authors: Li H , Zhou Y , Zhao A , Qiu Y , Xie G , Jiang Q , Zheng X , Zhong W , Sun X , Zhou Z , Jia W
Published: October 2013

Asymmetric dimethylarginine (ADMA) is synthesized by protein arginine methyltransferases during methylation of protein arginine residues and released into blood upon proteolysis. Higher concentrations of ADMA in blood have been observed in patients with metabolic diseases and certain cancers. However, the role of ADMA in colon cancer has not been well investigated. ADMA serum levels in human patients diagnosed with colon cancer were found to be higher than those present in healthy subjects. ADMA treatment of LoVo cells, a human colon adenocarcinoma cell line, attenuated serum starvation-induced apoptosis and suppressed the activation of the Fas (APO-1/CD95)/JNK (SAPK) (c-Jun N terminal protein kinase/stress-activated protein kinase)pathway. ADMA also suppressed the activation of JNK triggered by death receptor ligand anti-Fas mAb and exogenous C2-ceramide. Moreover, we demonstrated that ADMA pretreatment protected LoVo cells from doxorubicin hydrochloride-induced cell death and activation of the Fas/JNK pathway. In summary, our results suggest that the elevated ADMA in colon cancer patients may contribute to the blocking of apoptosis of cancer cells in response to stress and chemotherapy.
Empirical validation of viral quasispecies assembly algorithms: state-of-the-art and challenges
Authors: Prosperi Mattia C. F. , Yin Li , Nolan David J. , Lowe Amanda D. , Goodenow Maureen M. , Salemi Marco
Published: October 2013

Next generation sequencing (NGS) is superseding Sanger technology for analysing intra-host viral populations, in terms of genome length and resolution. We introduce two new empirical validation data sets and test the available viral population assembly software. Two intra-host viral population ‘quasispecies’ samples (type-1 human immunodeficiency and hepatitis C virus) were Sanger-sequenced and plasmid clone mixtures at controlled proportions were shotgun-sequenced using Roche's 454 sequencing platform. The performance of different assemblers was compared in terms of phylogenetic clustering and recombination with the Sanger clones. Phylogenetic clustering showed that all assemblers captured a proportion of the most divergent lineages, but none were able to provide a high precision/recall tradeoff. Estimated variant frequencies mildly correlated with the original. Given the limitations of currently available algorithms identified by our empirical validation, the development and exploitation of additional data sets is needed, in order to establish an efficient framework for viral population reconstruction using NGS.
An Introduction to Chemical Grouping, Categories and Read-Across to Predict Toxicity
Authors: Cronin M. T. D.
Published: October 2013

This chapter describes the need for toxicological information to determine the hazard of chemicals and hence allow for risk assessment. Specifically this chapter introduces the grouping together of similar chemicals into categories to allow for read­across, or interpolation, of toxicity. The history behind read­across, its context as an in silico method in addition to its advantages and disadvantages, as well as the purpose and process of category formation are described. This chapter is supported by an overview of the key literature and publicly available guidance in this area.
Elucidating asymmetric yield behavior of copper nano-wires during tensile and compressive load
Authors: Liu Wei-Ting , Hsiao Chun-I , Hsu Wen-Dung
Published: October 2013

Molecular dynamic simulations were performed to investigate the effects of tensile and compressive loading on the mechanical properties of face-centered cubic single-crystal copper [001] nano-wires with diameters ranging from 2 to 10 nm. Characterization of the initial optimized structures revealed large variations in interatomic spacing, stress, and potential energy in all nano-wires, which resulted in tensile stress for surface atoms and compressive stress for internal atoms. This phenomenon is more apparent in thin nano-wires (<6 nm) than thick nano-wires (≥10 nm). These variations are the origins of asymmetric yielding and asymmetric Poisson ratio in [001] copper nano-wires during tension and compression. For example, the Poisson's ratio exceeds 0.5 as the compressive strain approaches yield, indicating that the mechanical properties of single-crystal [001] nano-wire show strong directionality. The finding provides a fundamental understanding of the influence of the wire diameter on the mechanical properties of [001] nano-wires.
On fluid-solid direct coexistence simulations: The pseudo-hard sphere model
Authors: Espinosa Jorge R. , Sanz Eduardo , Valeriani Chantal , Vega Carlos
Published: October 2013

We investigate methodological issues concerning the direct coexistence method, an increasingly popular approach to evaluate the solid-fluid coexistence by means of computer simulations. The first issue is the impact of the simulation ensemble on the results. We compare the NpT ensemble (easy to use but approximate) with the NpzT ensemble (rigorous but more difficult to handle). Our work shows that both ensembles yield similar results for large systems (>5000 particles). Another issue, which is usually disregarded, is the stochastic character of a direct coexistence simulation. Here, we assess the impact of stochasticity in the determination of the coexistence point. We demonstrate that the error generated by stochasticity is much larger than that caused by the use of the NpT ensemble, and can be minimized by simply increasing the system size. To perform this study we use the pseudo hard-sphere model recently proposed by Jover et al. [J. Chem. Phys. 137, 144505 (2012)], and obtain a coexistence pressure of p* = 11.65(1), quite similar to that of hard spheres (only about 0.6% higher). Therefore, we conclude that this model can be reliably used to investigate the physics of hard spheres in phenomena like crystal nucleation.
Dynamics of glass-forming liquids. XVII. Dielectric relaxation and intermolecular association in a series of isomeric octyl alcohols
Authors: Singh Lokendra P. , Alba-Simionesco Christiane , Richert Ranko
Published: October 2013

It is well established that many mono-hydroxy alcohols show an extra relaxation process of the Debye type in addition to the signatures of primary and secondary structural relaxations, which is observed only in dielectric spectroscopy and related techniques. In order to gain further insight into the nature of this Debye peak, we study the linear and nonlinear dielectric behavior of a series of isomeric octyl alcohols and of mixtures of n-propanol with one of the octanols. These samples display systematic variations of the Debye peak intensity and concomitant changes in the Kirkwood correlation factor gK from 0.1 to 4, indicative of different equilibrium constants, Kc/r, that characterize the populations of non-polar ring and polar open chain structures. For cases where Kc/r is not too far from unity, we find that a high electric field shifts Kc/r towards more chains, and that the accompanying change in the end-to-end vector of hydrogen-bond connected structures occurs on the Debye time scale. The results suggest that gK is correlated with the spectral separation of the Debye and primary structural peaks, as both features depend on steric hindrance of chain flexibility or bond rotation barriers and on average chain lengths. Based on the complex dynamics of supercooled mono-hydroxy alcohols with three relaxation peaks that cover many orders of magnitude in frequency, it is argued that a frequency dependent gK may be required for assessing the average orientational correlations within hydrogen-bonded structures correctly.
Adhesion energy characterization of monolayer graphene by vibrational spectroscopy
Authors: Vahdat Armin Saeedi , Cetinkaya Cetin
Published: October 2013

As at nano/micro-scale van der Waals forces often dominate various other types of forces, the accurate adhesion characterization of graphene (Gr) is essential to its processing, manipulation, and possible integration into integrated circuits and other nano/micro-scale devices. Since 2010, the reported (experimental) adhesion energy of monolayer Gr with silicon dioxide (SiO2) has increased from 151 ± 28 mJ/m2 to 450 ± 20 mJ/m2. Here, we report a set of adhesion energy values for Gr monolayers on a SiO2 substrate by adopting a unique vibrational spectroscopy approach based on the motion of adhesive microparticles on a vibrating substrate. The reported results indicate that the work-of-adhesion measurements of monolayer Gr on SiO2 could be highly scattered and its mean value is determined as WSiO2−Gr = 1160.26 mJ/m2, which is the highest value reported to date. Unlike the reported existing methods, the current non-contact and non-destructive spectral technique requires no knowledge of the mechanical properties of Gr. Based on the reported data, with the current approach, it is also demonstrated that the weak adhesive interactions between a polystyrene latex microparticle and SiO2 substrate across the monolayer Gr can be detected as well.
Wear minimization through utilization of atomic-scale functional surface structure
Authors: Kim Hyun-Joon , Kim Dae-Eun
Published: October 2013

A method for wear minimization through utilization of an atomic-scale functional surface structure is proposed. The basic idea is to effectively dissipate the frictional energy generated during contact sliding so that its contribution to permanent displacement of atoms is minimized. This may be achieved by using a surface structure with optimum compliance that can accommodate the contact stresses through elastic, rather than permanent, deformation of the structure. This method was verified through molecular dynamics simulation of atomic-scale wear of a tip sliding against a hard coating layer that is supported by an atomic-scale functional surface structure.
Efficiency of dislocation density reduction during heteroepitaxial growth of diamond for detector applications
Authors: Stehl C. , Fischer M. , Gsell S. , Berdermann E. , Rahman M. S. , Traeger M. , Klein O. , Schreck M.
Published: October 2013

The development of dislocation density and micro-strain in heteroepitaxial diamond films on iridium was measured over more than two decades of thickness up to d ≈ 1 mm. Simple mathematical scaling laws were derived for the decrease of dislocation density with increasing film thickness and for its correlation with micro-strain. The Raman line width as a measure of micro-strain showed a huge decrease to 1.86 cm−1, close to the value of perfect single crystals. The charge collection properties of particle detectors built from this material yield efficiencies higher than 90% in the hole-drift mode, approaching the performance of homoepitaxial films.
Spectrally tailored mid-infrared super-continuum generation in a buried waveguide spanning 1750 nm to 5000 nm for atmospheric transmission
Authors: McCarthy J. , Bookey H. , Beecher S. , Lamb R. , Elder I. , Kar A. K.
Published: October 2013

We show how nonlinear spectral broadening in a buried chalcogenide mid-infrared waveguide can be used to reshape the spectrum of a femtosecond pulse train at 4260 nm in order to reduce the effects of atmospheric absorption due to carbon dioxide. The nonlinear spectral broadening results in the source with −20 dB spectral width spanning over 3500 nm, from 1700 nm to 5200 nm. This represents a potential route to tailored sources for long-range mid-infrared applications.
Effect of maize endosperm hardness, drying temperature and microbial enzyme supplementation on the performance of broiler chickens
Authors: Kaczmarek S. A. , Cowieson A. J. , Józefiak D. , Rutkowski A.
Published: October 2013

This study was conducted to determine the influence of maize endosperm type (soft or vitreous), drying temperature (60, 100, 140°C), and enzyme addition (no enzyme or phytase + xylanase) on broiler chicken growth, amino acid availability, and phytate phosphorus hydrolysis. One-day-old Ross-308 broiler chicks (total 1200) were allotted to floor pens with a randomised complete block design (2 × 3 × 2). Diets were formulated to be marginally deficient in Lys, total sulfur amino acids, calcium, and nonphytate phosphorus.
A positive effect (P < 0.05) of enzyme addition on chicken bodyweight gain to day 35 was observed (1884 vs 1940 g). Bodyweight gains and feed conversion ratios (FCR) were linearly depressed when drying temperature was increased. Chickens fed vitreous maize were characterised by lower bodyweight gain (1932 vs 1893 g; P < 0.05) and higher FCR (1.796 vs 1.840g : g; P < 0.05). There were no interactions between any of the main effects for overall performance metrics. The use of phytase improved phytic acid digestibility (0.302 vs 0.389; P < 0.05) but phytic acid digestibility was unaffected (P > 0.05) by drying temperature or hardness. The highest drying temperature had a negative effect on amino acids digestibility (P < 0.05). The use of phytase and xylanase improved amino acid apparent ileal digestibility (P < 0.05), except for Cys, Met, and Phe. Results from this study show that drying temperature and vitreousness of maize influence the nutritional value of this grain for broilers. Part of the beneficial effect of the addition of phytase + xylanase to diets with overheated maize for poultry appears to be mediated through an improvement in amino acid availability.
Functional genomics to study stress responses in crop legumes: progress and prospects
Authors: Kudapa Himabindu , Ramalingam Abirami , Nayakoti Swapna , Chen Xiaoping , Zhuang Wei-Jian , Liang Xuanqiang , Kahl Guenter , Edwards David , Varshney Rajeev K.
Published: October 2013

Legumes are important food crops worldwide, contributing to more than 33% of human dietary protein. The production of crop legumes is frequently impacted by abiotic and biotic stresses. It is therefore important to identify genes conferring resistance to biotic stresses and tolerance to abiotic stresses that can be used to both understand molecular mechanisms of plant response to the environment and to accelerate crop improvement. Recent advances in genomics offer a range of approaches such as the sequencing of genomes and transcriptomes, gene expression microarray as well as RNA-seq based gene expression profiling, and map-based cloning for the identification and isolation of biotic and abiotic stress-responsive genes in several crop legumes. These candidate stress associated genes should provide insights into the molecular mechanisms of stress tolerance and ultimately help to develop legume varieties with improved stress tolerance and productivity under adverse conditions. This review provides an overview on recent advances in the functional genomics of crop legumes that includes the discovery as well as validation of candidate genes.
Distribution and clinical correlates of viral and host genotypes in Chinese patients with chronic hepatitis C virus infection
Authors: Rao Huiying , Wei Lai , Lopez‐Talavera Juan Carlos , Shang Jia , Chen Hong , Li Jun , Xie Qing , Gao Zhiliang , Wang Lei , Wei Jia , Jiang Jianning , Sun Yongtao , Yang Ruifeng , Li Hong , Zhang Haiying , Gong Zuojiong , Zhang Lunli , Zhao Longfeng , Dou Xiaoguang , Niu Junqi , You Hong , Chen Zhi , Ning Qin , Gong Guozhong , Wu Shuhuan , Ji Wei , Mao Qing , Tang Hong , Li Shuchen , Wei Shaofeng , Sun Jian , Jiang Jiaji , Lu Lungen , Jia Jidong , Zhuang Hui
Published: October 2013

Background and Aim

Chronic hepatitis C virus (HCV) infection is relatively frequent in China. This study investigated the clinical, demographic, and viral and host genetic characteristics that may influence disease manifestations and clinical management.

Methods

In this cross‐sectional observational study, treatment‐naïve Han ethnic adults with recently confirmed chronic HCV infection were enrolled at 28 hospitals across China. HCV genotype and host interleukin 28B (IL28B) genotypes were determined and compared with patient demographic parameters and medical status.

Results

Among the 997 HCV‐positive patients analyzed, 56.8% were infected with HCV genotype 1b, followed in prevalence by genotypes 2, 3, and 6, with substantial regional variation. Overall, 84.1% of patients were IL28B genotype CC (rs12979860), with little regional variation. Cirrhosis was reported in 10.1% of patients and was significantly associated with hepatitis B virus coinfection, low HCV viral load, low serum alanine aminotransferase, high serum aspartate aminotransferase, diabetes, and high pickled food consumption. Medical procedures were common transmission risk factors; however, lifestyle‐associated risk factors, including intravenous drug abuse and tattoos or piercings, were more common in patients with HCV genotype 3 or 6.

Conclusions

Most HCV‐infected Han Chinese patients were IL28B genotype CC (rs12979860). HCV genotypes varied by geographic region, and disease characteristics differed according to HCV genotype. Relatively frequent detection of advanced liver disease may reflect limitations on access to antiviral therapy, and suggests that greater awareness of factors that influence HCV‐associated disease may help avoid clinical complications and improve patient outcomes.
Derived categories and rationality of conic bundles
Authors: Bernardara Marcello , Bolognesi Michele
Published: October 2013

We show that a standard conic bundle over a minimal rational surface is rational and its Jacobian splits as the direct sum of Jacobians of curves if and only if its derived category admits a semiorthogonal decomposition by exceptional objects and the derived categories of those curves. Moreover, such a decomposition gives the splitting of the intermediate Jacobian also when the surface is not minimal.
Corrigendum: On the use of a discrete form of the Itô formula in the article ‘Almost sure asymptotic stability analysis of the -Maruyama method applied to a test system with stabilising and destabilising stochastic perturbations’
Authors: Berkolaiko Gregory , Buckwar Evelyn , Kelly Cónall , Rodkina Alexandra
Published: October 2013

In the original article [LMS J. Comput. Math. 15 (2012) 71–83], the authors use a discrete form of the Itô formula, developed by Appleby, Berkolaiko and Rodkina [Stochastics 81 (2009) no. 2, 99–127], to show that the almost sure asymptotic stability of a particular two-dimensional test system is preserved when the discretisation step size is small. In this Corrigendum, we identify an implicit assumption in the original proof of the discrete Itô formula that, left unaddressed, would preclude its application to the test system of interest. We resolve this problem by reproving the relevant part of the discrete Itô formula in such a way that confirms its applicability to our test equation. Thus, we reaffirm the main results and conclusions of the original article.
Efficient Thermal-Impedance Simulation of Insulated-Gate Bipolar Transistors Modules on Heat Sinks
Authors: Gradinger Thomas B. , Drofenik Uwe
Published: October 2013

The prediction of temperatures in power semiconductor modules, such as insulated-gate bipolar transistors (IGBTs) is critical to ensure adequate lifetime modeling of the devices. A temperature of particular interest is that of the semiconductor junction, which is used to assess the lift-off of wire bonds. For many applications featuring dynamic loads, the junction temperature needs to be simulated for so-called mission profiles of significant duration. To limit the computational expense, the simulations are based on thermal impedances from junction to ambient, which may be obtained from numerical 3-d simulations. Even these 3-d simulations can be computationally expensive. In power-electronic systems, often, large heat sinks are used with a multitude of mounted IGBT modules, interacting thermally. In such cases, the detailed 3-d models become large and the transient simulations are not feasible. In the present work, a method is proposed that allows us to significantly reduce the 3-d model size. To this end, the ideas of compact or boundary-condition-independent models are used. The presented method has the advantage that, unlike in model-order reduction, the system matrices of the 3-d model are not needed. This makes the method applicable to commercial simulation software like ANSYS Icepak™, that does not give access to the system matrices. The method is implemented via MATLAB™ scripts that automatically generate 3-d ANSYS Icepak™ models of IGBT modules on a heat sink. An example case of two IGBT modules mounted on an air-cooled heat sink is presented, and the method is shown to yield good accuracy (thermal-impedance errors below 8% and thermal-resistance errors close to zero), while reducing the model's mesh size by the factor of 14. Further error reduction is expected to be possible by adapting the model parameters. This can be subject to future work.
Stress Mitigation Design of a Tubesheet by Considering the Thermal Stress Inducement Mechanism
Authors: Ando Masanori , Takasho Hideki , Kawasaki Nobuchika , Kasahara Naoto
Published: October 2013

Adoption of double-wall straight-tube steam generators (SGs) made of Mod.9Cr-1Mo steel is planned for next-generation fast breeder reactors (FBRs) in Japan. One of the major concerns with the SG is the structural integrity of the tubesheet. During a transient event, a maximum thermal stress may be induced by the temperature distribution in the tubesheet, and the magnitude of the stress depends on the configuration of the tubesheet. Therefore, the stress generation mechanism of a tubesheet was studied through finite element (FE) analysis. Semispherical tubesheet models were investigated for the first survey of the thermal stress mechanism. The calculated results of the semispherical tubesheet model indicated an extensive peak stress around the outermost hole. The recognized thermal stress mechanism of a semispherical tubesheet is as follows: (1) The dominant thermal stress is hoop stress caused by the temperature difference between the perforated and surrounding regions. (2) The thermal stress is insensitive to the size of the specific portion, although it is dominated by an interaction mechanism between the perforated and surrounding regions. (3) The stress concentration around the edge of the holes generates a peak stress. (4) The amplitude of the peak stress depends on the tubesheet penetration angle, and the stress concentration becomes greatest near the outermost hole. Based on the above stress generation mechanism, we proposed a stress-mitigated tubesheet, a center-flattened spherical tubesheet (CFST), as an improved configuration. The calculated peak stress of the CFST was smaller than that of the semispherical tubesheet. Further investigation revealed the detailed stress generation mechanism of the CFST during a thermal transient. There were, in fact, two different comparable thermal peak stress mechanisms observed for the CFST. Both the location and magnitude of the maximum peak stress depended on the steam temperature histories during the thermal transient. The radial stress caused by structural discontinuity, which was located at the outermost hole, depended on the rate (dT/dt) of the steam temperature change. The hoop stress caused by the interaction between the perforated and surrounding regions, which occurred at the first inner layer hole (with respect to the outermost layer holes) depended on the range (ΔT) of the steam temperature change.
Design of a Novel Long-Range Inflatable Robotic Arm: Manufacturing and Numerical Evaluation of the Joints and Actuation
Authors: Voisembert Sébastien , Mechbal Nazih , Riwan Alain , Aoussat Ameziane
Published: October 2013

The aim of this paper is to present the design of a new long-range robotic arm based on an inflatable structure. Inflatable robotics has potential for improved large payload-to-weight ratios, safe collision, and inspection in areas inaccessible to human beings as in nuclear plants. The robot presented here is intended to operate inspection or maintenance missions in critical installation taking care to not collide with its environment. It is made with innovative inflatable joints and an original actuation system. Prototypes of this inflatable manipulator were constructed using two different manufacturing procedures. Using ls-dyna nonlinear dynamic finite element modeling we have numerically analyzed the specific geometry and dynamical behavior of the resulting joints. The simulations have given insight into understanding the joint bending process and have revealed guidance for optimizing the conception.
Low Cycle Fatigue and Creep-Fatigue Behavior of Alloy 617 at High Temperature
Authors: Cabet Celine , Carroll Laura , Wright Richard
Published: October 2013

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the very high temperature nuclear reactor (VHTR), expected to have an outlet temperature as high as 950 °C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanisms and failure life. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950 °C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle fatigue specimens exhibited transgranular cracking. Intergranular cracking was observed in the creep-fatigue specimens and the addition of a hold time at peak tensile strain degraded the cycle life. This suggests that creep-fatigue interaction occurs and that the environment may be partially responsible for accelerating failure.
Calculation of Dynamic Stress Intensity Factors for Pipes During Crack Propagation by Dynamic Finite Element Analysis
Authors: Mitsuya Masaki , Motohashi Hiroyuki , Oguchi Noritake , Aihara Shuji
Published: October 2013

A dynamic finite element analysis method was proposed for calculating the dynamic stress intensity factors for pipes during crack propagation. The proposed method can directly calculate the stress intensity factors without the simplification used in theoretical analyses, and it can consider the effects of the crack velocity and gas decompression. It was found that the stress intensity factors of long propagating cracks in pipes saturated at a certain value in the case of a high crack velocity. However, the stress intensity factors for pipes were in good agreement with those of band plates in the case of a high crack velocity, the stress intensity factors for pipes were different from those of band plates in the case of a low crack velocity. This result could be explained by the effect of bulging on the stress distribution around a crack tip. The effect of bulging was more prominent for pipes with smaller diameters. In contrast, the dynamic stress intensity factors for band plates were in good agreement with the theoretical values that consider the dynamic effects and tended to decrease monotonically with increasing crack velocity. Additionally, the effects of gas decompression, caused by leakage from opened cracks, on the stress intensity factors for pipes were investigated. An explanation of the change in crack direction, reflecting a change from an axial crack to a circumferential crack, which is observed in actual pipeline fractures, was given by analyzing the ratio of the longitudinal stress to lateral stress.
Two-Degree-of-Freedom Decoupled Nonredundant Cable-Loop-Driven Parallel Mechanism
Authors: Liu Hanwei , Gosselin Clément , Laliberté Thierry
Published: October 2013

A novel two-degree-of-freedom (DOF) cable-loop slider-driven parallel mechanism is introduced in this paper. The novelty of the mechanism lies in the fact that no passive rigid-link mechanism or springs are needed to support the end-effector (only cables are connected to the end-effector) while at the same time there is no actuation redundancy in the mechanism. Sliders located on the edges of the workspace are used and actuation redundancy is eliminated while providing force closure everywhere in the workspace. It is shown that the two degrees of freedom of the mechanism are decoupled and only two actuators are needed to control the motion. There are two cable loops for each direction of motion: one acts as the actuating loop while the other is the constraint loop. Due to the simple geometric design, the kinematic and static equations of the mechanism are very compact. The stiffness of the mechanism is also analyzed in the paper. It can be observed that the mechanism's stiffness is much higher than the stiffness of the cables. The proposed mechanism's workspace is essentially equal to its footprint and there are no singularities.
Ultrathin, Molecular-Sieving Graphene Oxide Membranes for Selective Hydrogen Separation
Authors: Li Hang , Song Zhuonan , Zhang Xiaojie , Huang Yi , Li Shiguang , Mao Yating , Ploehn Harry J. , Bao Yu , Yu Miao
Published: October 2013

Gas Separations

When gas separation membranes are made thinner, they usually allow permeating gases to pass through faster. However, a thinner membrane may be poorer at separating between gas species.

Kim
et al.

(p.
91
) examined the permeability and selectivity of layered graphene and graphene oxide membranes. Gas molecules diffuse through defective pores and channels that form between the layers. Controlling these structures tuned the properties of the membranes to allow the extraction of carbon dioxide from other gases.

Li
et al.

(p.
95
) describe membranes as thin as 1.8 nanometers made from only two to three layers of graphene oxide. Small defects within the layers allowed hydrogen to pass through, separating it from carbon dioxide and nitrogen.
Mice Genetically Deficient in Vasopressin V1a and V1b Receptors Are Resistant to Jet Lag
Authors: Yamaguchi Yoshiaki , Suzuki Toru , Mizoro Yasutaka , Kori Hiroshi , Okada Kazuki , Chen Yulin , Fustin Jean-Michel , Yamazaki Fumiyoshi , Mizuguchi Naoki , Zhang Jing , Dong Xin , Tsujimoto Gozoh , Okuno Yasushi , Doi Masao , Okamura Hitoshi
Published: October 2013

Resetting the Circadian Clock

Fatigue and other symptoms of jet lag arise when the body's internal circadian clock is out of sync with environmental light-dark cycles. Studying genetically modified mice lacking two receptors for the peptide hormone vasopressin under experimental conditions simulating jet lag,

Yamaguchi
et al.

(p.
85
; see the Perspective by

Hastings

) concluded that vasopressin signaling in the suprachiasmatic nucleus (SCN)—a region of the brain known to control circadian rhythms—impedes adjustment to the environmental clock. Infusion of vasopressin receptor antagonists directly into the SCN of wild-type mice accelerated their recovery from jet lag, suggesting that this pathway may merit further investigation as a pharmacological target for treating jet lag.
From Matter to Self-Organizing Life
From Strange Simplicity to Complex Familiarity
A Treatise on Matter, Information, Life, and Thought

by Manfred Eigen

Oxford University Press, Oxford, 2013. 754 pp. $225, £125. ISBN 9780198570219.
Authors: Traulsen Arne
Published: October 2013

Through a collection of 50 questions and associated stories, Eigen offers a wide-ranging consideration of "the physical nature of information and its role in life processes."
The IPCC Gains Confidence in Key Forecast
Authors: Kerr Richard A.
Published: October 2013

The latest international climate assessment may appear to rubberstamp the same old guess of how bad global warming will get, but the science is now actually much advanced.
Hey, You've Got to Hide Your Work Away
Authors: Malakoff David
Published: October 2013

Debate is simmering over how and when to publish sensitive data.
Effects of Substitutions at the 4′ and 2 Positions on the Bioactivity of 4′-Ethynyl-2-Fluoro-2′-Deoxyadenosine
Authors: Kirby Karen A. , Michailidis Eleftherios , Fetterly Tracy L. , Steinbach Musetta A. , Singh Kamalendra , Marchand Bruno , Leslie Maxwell D. , Hagedorn Ariel N. , Kodama Eiichi N. , Marquez Victor E. , Hughes Stephen H. , Mitsuya Hiroaki , Parniak Michael A. , Sarafianos Stefan G.
Published: October 2013

Nucleos(t)ide reverse transcriptase inhibitors (NRTIs) form the backbone of most anti-HIV therapies. We have shown that 4′-ethynyl-2-fluoro-2′-deoxyadenosine (EFdA) is a highly effective NRTI; however, the reasons for the potent antiviral activity of EFdA are not well understood. Here, we use a combination of structural, computational, and biochemical approaches to examine how substitutions in the sugar or adenine rings affect the incorporation of dA-based NRTIs like EFdA into DNA by HIV RT and their susceptibility to deamination by adenosine deaminase (ADA). Nuclear magnetic resonance (NMR) spectroscopy studies of 4′-substituted NRTIs show that ethynyl or cyano groups stabilize the sugar ring in the C-2′-exo/C-3′-endo (north) conformation. Steady-state kinetic analysis of the incorporation of 4′-substituted NRTIs by RT reveals a correlation between the north conformation of the NRTI sugar ring and efficiency of incorporation into the nascent DNA strand. Structural analysis and the kinetics of deamination by ADA demonstrate that 4′-ethynyl and cyano substitutions decrease the susceptibility of adenosine-based compounds to ADA through steric interactions at the active site. However, the major determinant for decreased susceptibility to ADA is the 2-halo substitution, which alters the pK
a
of N1 on the adenine base. These results provide insight into how NRTI structural attributes affect their antiviral activities through their interactions with the RT and ADA active sites.
Trends in Human Fecal Carriage of Extended-Spectrum β-Lactamases in the Community: Toward the Globalization of CTX-M
Authors: Woerther Paul-Louis , Burdet Charles , Chachaty Elisabeth , Andremont Antoine
Published: October 2013

In the last 10 years, extended-spectrum β-lactamase-producing enterobacteria (ESBL-E) have become one of the main challenges for antibiotic treatment of enterobacterial infections, largely because of the current CTX-M enzyme pandemic. However, most studies have focused on hospitalized patients, though today it appears that the community is strongly affected as well. We therefore decided to devote our investigation to trends in ESBL-E fecal carriage rates and comprehensively reviewed data from studies conducted on healthy populations in various parts of the world. We show that (i) community ESBL-E fecal carriage, which was unknown before the turn of the millennium, has since increased significantly everywhere, with developing countries being the most affected; (ii) intercontinental travel may have emphasized and globalized the issue; and (iii) CTX-M enzymes, especially CTX-M-15, are the dominant type of ESBL. Altogether, these results suggest that CTX-M carriage is evolving toward a global pandemic but is still insufficiently described. Only a better knowledge of its dynamics and biology will lead to further development of appropriate control measures.
A Current Perspective on Daptomycin for the Clinical Microbiologist
Authors: Humphries Romney M. , Pollett Simon , Sakoulas George
Published: October 2013

Daptomycin is a lipopeptide antimicrobial with
in vitro
bactericidal activity against Gram-positive bacteria that was first approved for clinical use in 2004 in the United States. Since this time, significant data have emerged regarding the use of daptomycin for the treatment of serious infections, such as bacteremia and endocarditis, caused by Gram-positive pathogens. However, there are also increasing reports of daptomycin nonsusceptibility, in
Staphylococcus aureus
and, in particular,
Enterococcus faecium
and
Enterococcus faecalis
. Such nonsusceptibility is largely in the context of prolonged treatment courses and infections with high bacterial burdens, but it may occur in the absence of prior daptomycin exposure. Nonsusceptibility in both
S. aureus
and
Enterococcus
is mediated by adaptations to cell wall homeostasis and membrane phospholipid metabolism. This review summarizes the data on daptomycin, including daptomycin's unique mode of action and spectrum of activity and mechanisms for nonsusceptibility in key pathogens, including
S. aureus
,
E. faecium
, and
E. faecalis
. The challenges faced by the clinical laboratory in obtaining accurate susceptibility results and reporting daptomycin MICs are also discussed.
Evaluation of Commercially Available Reagents for Diagnosis of Histoplasmosis Infection in Immunocompromised Patients
Authors: Zhang Xiaochun , Gibson Bill , Daly Thomas M.
Published: October 2013

Urinary histoplasma antigen measurement can be useful for diagnosing systemic histoplasmosis and for monitoring treatment response, especially in immunocompromised patients. However, testing has traditionally been limited to specialized reference laboratories, as immunoassay reagents for the antigen were not widely available. Recently, a polyclonal-antibody-based
in vitro
diagnostic (IVD) kit for histoplasma antigen detection was released, as well as monoclonal-antibody reagents against the target. We evaluated the analytical and clinical performance of the two reagents. Both assays were capable of detecting histoplasma antigen in urine samples over a wide dynamic range, although the monoclonal assay showed improved precision and analytical sensitivity relative to the polyclonal IVD. In a test set of clinically characterized patient samples, the monoclonal laboratory-developed test (LDT) demonstrated 90.5% sensitivity and 96.3% specificity versus 61.9% sensitivity and 79.3% specificity for the polyclonal IVD, with areas under the curve (AUCs) of 0.987 and 0.754, respectively. The major differences between the two assays were higher background reactivity in healthy donors with the polyclonal assay and an increased signal response in positive samples for the monoclonal assay. The impact of these differences on monitoring treatment response was evaluated in a series of patients undergoing treatment for histoplasmosis. While all the assays gave similar qualitative estimates of treatment response, responses were more evident using the monoclonal assay. In summary, we conclude that while multiple assays are available for measuring histoplasma antigen in urine, a monoclonal-antibody-based assay appears to provide improved analytical performance for management of immunocompromised histoplasmosis patients.