bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct differentiation of stereoisomers of ezetimibe/ambrisentan/atorvastatin and their mechanism study by electrospray ionization quadrupole time‐of‐flight mass spectrometry
Authors: Wang Lu , Wang Yali , Yu Lushan , Sun Cuirong , Kang Yu , Zeng Su 
Published: October 2018

AbstractA mass spectrometric method is introduced for rapid and accurate chiral quantification by examining a trimeric metal complex into which a chiral reference is incorporated with the analyte. Several metal ions (CuII, NiII, MgII, MnII, CoII, and ZnII) were selected as the central metal ion, and chiral drugs ezetimibe (EZM) and ambrisentan (AMB) were used as the reference to each other for isomeric differentiation by using electrospray ionization quadrupole time‐of‐flight mass spectrometry. Doubly charged trimeric cluster ions instead of the singly charged clusters were applied in this study. Kinetic method (KM) and chiral recognition (CR) method were used for construction of a calibration curve for chiral quantitation. The results from the two methods were found to be complementary to each other, which improved quantitative analysis of stereoisomers for EZM. Furthermore, we have successfully used S‐AMB as reference for the chiral differentiation of enantiomeric atorvastatin (ATO), which is frequently combined with EZM as a codrug. Experimental results showed that the binary mixture of EZM and ATO enantiomers can be determined simultaneously without prior separation steps. The direct measurement of chiral purity within 5% was demonstrated. This mass spectrometric method represents an effective alternative to commonly used chromatographic techniques as means of chiral purity determination and is of potential use in rapid screening experiments.
Seasonal space use and habitat selection of sambar in Taiwan
Authors: Yen Shih‐Ching , Wang Ying , Yu Pin‐Huan , Kuan Yuan‐Peng , Liao Yu‐Chuan , Chen Kuang‐Hsun , Weng Guo‐Jing 
Published: October 2018

ABSTRACTSambar (Rusa unicolor) in Taiwan experienced overexploitation by humans before the 1990s. In recent years, however, the population has recovered rapidly, and has become regionally abundant, resulting in damage to forests in some conservation areas. We investigated space use and habitat selection of sambar using global positioning system telemetry and resource selection function models. We collected sambar locations from 12 collared deer (6 males and 6 females) from December 2009 to March 2014 in Taroko National Park, Taiwan. Males had the largest mean home range size during the hot‐wet season (May–Oct, 95% fixed kernel method: 1.43 ± 0.23 km2). Males in the cold‐dry season (Nov–Apr) and females in both seasons had similar mean home range sizes of approximately 0.70 km2. Sambar moved to higher elevations during the hot–wet season and moved to lower elevations during the cold–dry season. Sambar preferred cypress (Chamaecyparis spp.) forest, pine (Pinus spp.) forest, fir (Abies spp.)‐hemlock (Tsuga spp.) forest, or thicket to broad‐leaved forest and open areas during both seasons. In addition, they preferred areas that were humid and had moderate solar radiation. We recommend estimating sambar population density in the cold–dry season when males and females have similar home range sizes. We predict that the rapid growth of the sambar population in Taiwan will be restrained as they expand to lower elevations because they prefer alpine landcover types and sambar habitats at lower elevations are fragmented. © 2018 The Wildlife Society.
Factors influencing nesting ecology of lesser prairie‐chickens
Authors: Lautenbach Joseph M. , Haukos David A. , Sullins Daniel S. , Hagen Christian A. , Lautenbach Jonathan D. , Pitman James C. , Plumb Reid T. , Robinson Samantha G. , Kraft John D. 
Published: October 2018

ABSTRACTLesser prairie‐chicken (Tympanuchus pallidicinctus) populations have declined since the 1980s. Understanding factors influencing nest‐site selection and nest survival are important for conservation and management of lesser prairie‐chicken populations. However, >75% of the extant population is in the northern extent of the range where data on breeding season ecology are lacking. We tested factors influencing fine‐scale and regional nest‐site selection and nest survival across the northern portion of the lesser prairie‐chicken range. We trapped and affixed satellite global positioning system and very high frequency transmitters to female lesser prairie‐chickens (n = 307) in south‐central and western Kansas and eastern Colorado, USA. We located and monitored 257 lesser prairie‐chicken nests from 2013 to 2016. We evaluated nest‐site selection and nest survival in comparison to vegetation composition and structure. Overall, nest‐site selection in relation to vegetation characteristics was similar across our study area. Lesser prairie‐chickens selected nest microsites with 75% visual obstruction 2.0–3.5 dm tall and 95.7% of all nests were in habitat with ≥1 dm and ≤4 dm visual obstruction. Nests were located in areas with 6–8% bare ground, on average, avoiding areas with greater percent cover of bare ground. The type of vegetation present was less important than cover of adequate height. Nest survival was maximized when 75% visual obstruction was 2.0–4.0 dm. Nest survival did not vary spatially or among years and generally increased as intensity of drought decreased throughout the study although not significantly. To provide nesting cover considering yearly variation in drought conditions, it is important to maintain residual cover by managing for structural heterogeneity of vegetation. Managing for structural heterogeneity could be accomplished by maintaining or strategically applying practices of the Conservation Reserve Program, using appropriate fire and grazing disturbances in native working grasslands, and establishing site‐specific monitoring of vegetation composition and structure. © 2018 The Wildlife Society.
Effects of soil type, temperature, moisture, application dose, fertilizer, and organic amendments on chemical properties and biodegradation of dimethyl disulfide in soil
Authors: Han Dawei , Yan Dongdong , Wang Qiuxia , Fang Wensheng , Wang Xianli , Li Jun , Wang Dong , Li Yuan , Ouyang Canbin , Cao Aocheng 
Published: October 2018

AbstractDimethyl disulfide (DMDS) is a potential alternative to methyl bromide for soil fumigation to control soil‐borne disease. Laboratory experiments were conducted to investigate the effects of combinations of soil and environmental factors of DMDS degradation in soil. The results showed that soil pH and soil organic matter content are the major factors influencing the degradation of DMDS in soil. Generally, DMDS degradation was significantly slower in acidic and high organic content soils. The degradation rate increased with temperature and water content. However, when the temperature exceeded 35°C, the degradation rate decreased, and when the soil water content was raised to 10%, the change in DMDS degradation was not significant in Fangshan soil. The degradation of DMDS in soil depended on the initial application rate. Degradation slowed down as the fumigant application rate increased. DMDS degradation in soil was restrained by the addition of organic matter to soil, and the effect was enhanced by increased dosage. DMDS degradation in soil was also restrained by the use of chemical fertilizers except when amended with sodium dihydrogen phosphate and sodium thiosulfate. The impact of fumigant application rates and chemical fertilizers on bacterial communities in soil was determined by 16S rRNA amplicon sequencing. The results showed that bacterial diversity was affected by different treatments. Our study provides useful information to evaluate environmental safety assessments of DMDS in soil.
Analysis of drought and vulnerability in the North Darfur region of Sudan
Authors: Mohmmed Alnail , Zhang Ke , Kabenge Martin , Keesstra Saskia , Cerdà Artemi , Reuben Makomere , Elbashier Mohammed M.A. , Dalson Twecan , Ali Albashir A.S. 
Published: October 2018

AbstractNorth Darfur of Sudan is located on the edge of the Sahara Desert and endures frequent droughts due to water shortages and high summer temperatures. Monitoring and understanding drought characteristics are essential for integrated drought risk mitigation and prevetion of land degradation. This study evaluates drought conditions in North Darfur by analyzing the spatiotemporal distribution of drought using three drought indices (Standardized Precipitation Index, Vegetation Condition Index, and Soil Moisture Content Index) and their combined drought index (CDI) from 2004 to 2013. Biophysical and socioeconomic indicators are further used to measure vulnerability to drought risk and its three components (exposure, sensitivity, and adaptive capacity) through a comprehensive risk assessment framework. The results show that most of North Darfur has experienced prolonged droughts during the study period, especially from 2007 to 2011. There is also a significant correlation between the monsoon season CDI and annual crop yield anomaly. The results confirm the validity of the CDI index, which provides a comprehensive description of the drought situation by combing four drought indices quantifying different drought aspects. The vulnerability results show that the majority of this region is highly exposed and sensitive to drought risks. In particular, the northern zone of the region is highly vulnerable, which is categorized by less‐crop diversity, higher land degradation, frequent droughts, and high‐poverty levels. This study provides valuable information for coping with climate change‐induced drought risk in this region and demonstrates that there is still a large room for enhancing the adaptation capacity in this region.
Furfuryl‐ and Maleimido Polysaccharides: Synthetic Strategies Toward Functional Biomaterials
Authors: Elschner Thomas , Obst Franziska , Heinze Thomas 
Published: October 2018

AbstractIn context with facile and efficient syntheses of functional polymeric materials, the combination of polysaccharides and functional moieties based on renewable resources is a sustainable and valuable approach. This review presents alternatives to prominent click reactions utilizing biopolymer derivatives with furfuryl and maleimide groups. On the one hand, the cross‐linking by Diels–Alder reaction of these polymers enables the synthesis of novel materials in the fields of self‐healing polymers, tissue engineering, and drug delivery. On the other hand, thiol‐ene click reactions allow their conjugation to complex (bio)molecules. Different synthetic strategies are reviewed and the applicability of functional materials is evaluated.
Comparison of superplastic forming abilities of as‐cast AZ91 magnesium alloy prepared by twin roll casting and WE43 magnesium alloy
Authors: Taylor S. , Janik V. , Grimes R. , Mogire E. , Dashwood R. 
Published: October 2018

AbstractThis paper describes and compares the superplastic behaviour and microstructural evolution of twin roll cast AZ91 and WE43 rolled sheet alloys. Tests were carried out in uniaxial tension on both alloys across a range of temperatures (300 °C–525 °C) and strain rates (1⋅10‐4 s‐1–1⋅10‐1 s‐1). In the case of WE43 gas bulge testing was employed at 400 °C and 0.6 MPa to offer a better analogy to superplastic forming than uniaxial tensile testing. Elongations of over 400 % were observed within WE43 when tested at 450 °C and 1⋅10‐3 s‐1 strain rate, and over 200 % within AZ91 when tested at 350 °C and 1⋅10‐3 s‐1 strain rate. A peak cone height of 41 mm was achieved with WE43 at a temperature of 400 °C and pressure of 0.6 MPa. Electron back scattered detection technique was employed to analyse the microstructural evolution of the two alloys during the forming process. Both WE43 and AZ91 were observed to undergo dynamic recrystallization during elevated temperature tensile testing and failed at low strain rates mainly by means of coalescence of cavitation, in the case of AZ91 at high strain rates cracking of Al12Mg17 intermetallic particles was the dominating failure mechanism. Both alloys were seen to achieve good levels of superplastic ductility over 200 % elongation, which would be industrially useful in niche vehicle and aerospace manufacturing.
Texture and mechanical properties of single crystal copper during equal channel angular pressing by route C
Authors: Guo T.B. , Li Q. , Wang C. , Jia Z. , Hu Y. , Tang X.C. 
Published: October 2018

AbstractSingle crystal copper has excellent electrical and thermal conductivity, but the lower strength seriously limited its application. Traditional strengthening methods, such as alloying, will severely damage its conductivity. Severe plastic deformation is the most effective methods for increasing the metals strength and not reducing the conductivity. The microstructure and texture evolution of single crystal copper (99.999 %) during equal channel angular pressing by route C was investigated by scanning electron microscopy, X‐ray diffraction, electron backscatter diffraction and transmission electron microscopy, the mechanical properties and conductivity were tested, and the influence mechanism of texture and microstructure on mechanical properties and conductivity were analyzed. The results show that during equal channel angular pressing, the original <111> orientation gradually changed to <001>, accompany lots of low‐angle grain boundaries were formed. With strain increasing, the high‐angle grain boundaries increased gradually, and the deformation bands with <110> orientation was formed in the single crystal structure, which plays a positive role on the conductivity. After 5 passes, the tensile strength of single crystal copper increased from 168 MPa to 415 MPa by route A and 385 MPa by route C, and the elongation declined sharply from 63 % to 30 % and 27.9 %, respectively. After 16 passes, the hardness increased from 60.4 HV to 130.8 HV and the conductivity only slightly down.magnified image
High‐performance Cu/Al laminated composites fabricated by horizontal twin‐roll casting
Authors: Liu S. Y. , Wang A. Q. , Lu S. J. , Xie J. P. 
Published: October 2018

AbstractHorizontal twin‐roll casting technology was successfully introduced to produce high‐performance copper/aluminum (Cu/Al) laminated composites. The interface morphology, electrical properties and peeling strength after different annealing and cold rolling processes were investigated and contrasted with Cu/Al clad plates fabricated by conventional methods. The results show that sound metallurgical bonding between the copper and aluminum matrix can be attained after the horizontal twin‐roll casting processes and Al2Cu is the only intermetallics at the interfacial region, the thickness of interfacial interlayer is about 0.7 μm. The peeling strength is 31.4 N/mm and can be further increased to 37.1 N/mm after annealing at 250 °C. However, higher temperature like 400 °C will cause the excessive growth of intermetallics so that peeling strength sharply decreases to 9.2 N/mm. Electrical conductivity of the clad plate is 51 MS/m. At the same electrical current intensity, the temperature‐rise of the composite plate is between the pure copper plate and the aluminum plate, and closer to the copper plate. All of the properties are outstanding than that of Cu/Al clad plate fabricated by conventional methods.
Investigation of the damage evolution of metal inserts embedded in carbon fiber reinforced plastic by means of computed tomography and acoustic emission
Authors: Pottmeyer F. , Schlegel O. , Weidenmann K.A. , Merzkirch M. 
Published: October 2018

AbstractCarbon fiber reinforced plastics are promising materials for lightweight structures, for instance in automotive applications due to their outstanding specific mechanical properties. However, the load transfer in structural carbon fiber reinforced plastics parts via a detachable connection poses a challenge for the composite. Conventionally, the parts have to be drilled for this purpose whereby the fiber continuity is interrupted and hence the associated local stress accumulation decreases the load bearing capacity of the composite. This can be prevented by using embedded metal elements, so‐called inserts, for joining parts in structures. The damage behavior under tensile loading of inserts turned out to be extremely complex and is based on different mechanisms. In order to understand the damage evolution under tensile loading detailed knowledge about the deformation of the insert, crack growth in the laminate and debonding between metal insert and carbon fiber reinforced plastics is necessary. This paper aims for an investigation of the in situ failure behavior during tensile loading of composite sheets equipped with two different types of inserts by means of acoustic emission and computed tomography analysis. An inductive strain gauge was additionally installed underneath the laminate when performing the tensile tests monitored by acoustic emission analysis.
The role of compatible solutes in desiccation resistance of Acinetobacter baumannii
Authors: Zeidler Sabine , Müller Volker 
Published: October 2018

AbstractAcinetobacter baumannii is a nosocomial pathogen which can persist in the hospital environment not only due to the acquirement of multiple antibiotic resistances, but also because of its exceptional resistance against disinfectants and desiccation. A suitable desiccation assay was established in which A. baumannii ATCC 19606T survived for ca. 1 month. The growth medium slightly influenced survival after subsequent desiccation. A significant effect could be attributed to the growth phase in which bacteria were dried: In exponential phase, cells were much more desiccation sensitive. The main focus of the present study was the elucidation of the role of compatible solutes, which are known to protect many bacteria under low water activity conditions, in desiccation survival of A. baumannii. Exogenous trehalose was shown to efficiently protect A. baumannii on dry surfaces, in contrast to other compatible solutes tested such as mannitol or glycine betaine. To analyze the importance of intracellularly accumulated solutes, a double mutant lacking biosynthesis pathways for mannitol and trehalose was generated. This mutant accumulated glutamate as sole solute in the presence of high NaCl concentrations and showed severe growth defects under osmotic stress conditions. However, no effect on desiccation tolerance could be seen, neither when cells were dried in water nor in the presence of NaCl.
A comparison of preconditioned Krylov subspace methods for large‐scale nonsymmetric linear systems
Authors: Ghai Aditi , Lu Cao , Jiao Xiangmin 
Published: October 2018

SummaryPreconditioned Krylov subspace (KSP) methods are widely used for solving large‐scale sparse linear systems arising from numerical solutions of partial differential equations (PDEs). These linear systems are often nonsymmetric due to the nature of the PDEs, boundary or jump conditions, or discretization methods. While implementations of preconditioned KSP methods are usually readily available, it is unclear to users which methods are the best for different classes of problems. In this work, we present a comparison of some KSP methods, including GMRES, TFQMR, BiCGSTAB, and QMRCGSTAB, coupled with three classes of preconditioners, namely, Gauss–Seidel, incomplete LU factorization (including ILUT, ILUTP, and multilevel ILU), and algebraic multigrid (including BoomerAMG and ML). Theoretically, we compare the mathematical formulations and operation counts of these methods. Empirically, we compare the convergence and serial performance for a range of benchmark problems from numerical PDEs in two and three dimensions with up to millions of unknowns and also assess the asymptotic complexity of the methods as the number of unknowns increases. Our results show that GMRES tends to deliver better performance when coupled with an effective multigrid preconditioner, but it is less competitive with an ineffective preconditioner due to restarts. BoomerAMG with a proper choice of coarsening and interpolation techniques typically converges faster than ML, but both may fail for ill‐conditioned or saddle‐point problems, whereas multilevel ILU tends to succeed. We also show that right preconditioning is more desirable. This study helps establish some practical guidelines for choosing preconditioned KSP methods and motivates the development of more effective preconditioners.
A hybrid variational Allen‐Cahn/ALE scheme for the coupled analysis of two‐phase fluid‐structure interaction
Authors: Joshi Vaibhav , Jaiman Rajeev K. 
Published: October 2018

SummaryWe present a partitioned iterative formulation for the modeling of fluid‐structure interaction (FSI) in two‐phase flows. The variational formulation consists of a stable and robust integration of three blocks of differential equations, viz, an incompressible viscous fluid, a rigid or flexible structure, and a two‐phase indicator field. The fluid‐fluid interface between the two phases, which may have high density and viscosity ratios, is evolved by solving the conservative phase‐field Allen‐Cahn equation in the arbitrary Lagrangian‐Eulerian coordinates. While the Navier‐Stokes equations are solved by a stabilized Petrov‐Galerkin method, the conservative Allen‐Cahn phase‐field equation is discretized by the positivity preserving variational scheme. Fully decoupled implicit solvers for the two‐phase fluid and the structure are integrated by the nonlinear iterative force correction in a staggered partitioned manner and the generalized‐α method is employed for the time marching. We assess the accuracy and stability of the phase‐field/ALE variational formulation for two‐ and three‐dimensional problems involving the dynamical interaction of rigid bodies with free surface. We consider the decay test problems of increasing complexity, namely, free translational heave decay of a circular cylinder and free rotation of a rectangular barge. Through numerical experiments, we show that the proposed formulation is stable and robust for high density ratios across fluid‐fluid interface and for low structure‐to‐fluid mass ratio with strong added‐mass effects. Overall, the proposed variational formulation produces results with high accuracy and compares well with available measurements and reference numerical data. Using unstructured meshes, we demonstrate the second‐order temporal accuracy of the coupled phase‐field/ALE method via decay test of a circular cylinder interacting with the free surface. Finally, we demonstrate the three‐dimensional phase‐field FSI formulation for a practical problem of internal two‐phase flow in a flexible circular pipe subjected to vortex‐induced vibrations due to external fluid flow.