bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Electronic Nature and Reactivity of the Larger Acenes
Authors: Thorley Karl J. , Anthony John E. 
Published: May 2014

AbstractThe astounding electronic performance of acenes such as tetracene and pentacene (and their heteroaromatic counterparts) stands to revolutionize the field of organic electronics, promising novel consumer electronics for power generation and information display in lightweight, flexible form factors. These results have rekindled interest in acenes larger than pentacene, to determine how electronic properties are further altered by extending conjugation. This research has had to encompass many fundamental studies, as even the simple nature of aromaticity in larger acenes is still a controversial topic. Further, the reactivity of acenes toward oligomerization or oxidation becomes significant in larger acenes, while the diminishing solubility complicates isolation and characterization. This article surveys recent works describing the nature of aromaticity and reactivity in larger acenes, methods used to prepare parent acenes larger than pentacene, and functionalization approaches to soluble, reasonably stable large acenes.
Regulation of apoptosis by heat shock proteins
Authors: Kennedy Donna , Jäger Richard , Mosser Dick D , Samali Afshin 
Published: May 2014

AbstractThermotolerance, the acquired resistance of cells to stress, is a well‐established phenomenon. Studies of the key mediators of this response, the heat shock proteins (HSPs), have led to the discovery of the important roles played by these proteins in the regulation of apoptotic cell death. Apoptosis is critical for normal tissue homeostasis and is involved in diverse processes including development and immune clearance. Apoptosis is tightly regulated by both proapoptotic and antiapoptotic factors, and dysregulation of apoptosis plays a significant role in the pathophysiology of many diseases. In the recent years, HSPs have been identified as key determinants of cell survival, which can modulate apoptosis by directly interacting with components of the apoptotic machinery. Therefore, manipulation of the HSPs could represent a viable strategy for the treatment of diseases. Here, we review the current knowledge with regard to the mechanisms of HSP‐mediated regulation of apoptosis. © 2014 IUBMB Life, 66(5):327–338, 2014
Effects of calcium‐modified titanium implant surfaces on platelet activation, clot formation, and osseointegration
Authors: Anitua Eduardo , Prado Roberto , Orive Gorka , Tejero Ricardo 
Published: May 2014

AbstractThe clinical success of load bearing dental and orthopedic implants relies on adequate osseointegration. Because of its favorable properties, titanium is generally considered as the material of choice. Following implant placement, titanium surfaces establish an ionic equilibrium with the surrounding tissues in which calcium plays major roles. Calcium is a cofactor of the coagulation cascade that mediates plasma protein adsorption and intervenes in a number of other intra and extracellular processes relevant for bone regeneration. In this study, titanium surfaces were modified with calcium ions (Ca2+surfaces) and their responses toin vitroandin vivomodels were analyzed. Unlike unmodified surfaces, Ca2+surfaces were superhydrophilic and induced surface clot formation, platelet adsorption and activation when exposed to blood plasma. Interestingly,in vivoosseointegration using a peri‐implant gap model in rabbit demonstrated that Ca2+surfaces significantly improved peri‐implant bone volume and density at 2 weeks and bone implant contact at 8 weeks as compared to the unmodified controls. The combination of Ca2+surfaces with plasma rich in growth factors produced significantly more bone contact already at 2 weeks of implantation. These findings suggest the importance of the provisional matrix formation on tissue integration and highlight the clinical potential of Ca2+titanium surfaces as efficient stimulators of implant osseointegration. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 969–980, 2015.
Supported Palladium Oxide Nanoparticles in SBA‐15 as a Heterogeneous Catalyst for the Aerobic Oxidation of Alcohols
Authors: Atashin Hassan , Malakooti Reihaneh 
Published: May 2014

AbstractPalladium nanoparticles were first synthesized through the thermal decomposition method and subsequently immobilized on ordered mesoporous silica material, SBA‐15, to afford PdO/SBA‐15 catalyst. The synthesized catalyst was characterized by X‐ray diffraction, nitrogen adsorption‐desorption measurement, transmission electron microscopy, and inductively coupled plasma atomic emission spectrometry. The catalytic activity was tested for the aerobic oxidation of alcohols. Easy recovery, high yeilds and relatively short reaction times were observed for the mentioned catalyst.
Distance‐dependent Enhancement in Raman Spectroscopy Probed by Conjugated Molecules with Different Molecular Lengths
Authors: Maggie Liou Yen‐Chen , Chen Jiann‐Yeu , Yang Jyisy 
Published: May 2014

AbstractIn this study, the distance‐dependent enhancement effect in surface‐enhanced Raman scattering (SERS) was explored with molecules bearing different lengths of conjugated double bonds. These conjugated molecules were synthesized utilizing the diazotization‐coupling reaction allowing a thio group on one end and a nitro group on the other end. The thiol group allows the probed molecule to chemisorb on the surface of silver nanoparticles (AgNPs). The opposite end of each molecule contains a nitro group, which gives an intense SERS signal to show a fair and accurate comparison of the effect of chain length. The obtained SERS intensities were correlated with the chain lengths of these synthesized molecules, which ranged from 0.6 to 2.0 nm between the nitro and thiol groups. Based on these results, the electromagnetic field effect was mainly responsible for the signal enhancements in SERS measurements. Also, the obtained signals were exponentially decayed due to the distances of the surface of AgNPs. Based on the SERS intensities of the conjugated molecules, the contribution of CT effect to SERS for these examined molecules were limited.
Elaidic acid (EA) generates dysfunctional high‐density lipoproteins and consumption of EA exacerbates hyperlipidemia and fatty liver change in zebrafish
Authors: Park Ki‐Hoon , Kim Jong‐Min , Cho Kyung‐Hyun 
Published: May 2014

ScopeIt is well known thattrans‐fatty acids have proatherogenic properties while HDL has antiatherogenic activities in plasma. However, there has been no report on the effects oftrans‐fat on the functional and structural properties of HDL.Methods and resultsTo compare physiological properties, we synthesized reconstituted HDL (rHDL) containing stearic acid (18:0), oleic acid (18:1,cis), or elaidic acid (EA, 18:1,trans). An rHDL containing EA (EA‐rHDL) showed loss of antioxidant ability and induced the highest uptake of oxidized LDL into human macrophages. EA‐rHDL caused the strongest cellular senescence in human dermal fibroblast cells along with the highest production of inflammatory species in macrophages co‐treated with fructose. Injection of EA‐rHDL into zebrafish embryos resulted in acute embryonic toxicity with the lowest survivability. Consumption oftrans‐fat for 20 weeks resulted in remarkable hyperlipidemia, elevation of serum cholesteryl ester transfer protein activity, hepatic inflammation, and fatty liver changes.ConclusionIncorporation of EA impaired the beneficial effects of rHDL against atherogenesis. In zebrafish, EA‐rHDL resulted in acute embryonic toxicity, and consumption of EA caused remarkable hyperlipidemia, inflammation, and fatty liver changes.
Uniform convergence analysis of hybrid numerical scheme for singularly perturbed problems of mixed type
Authors: Mukherjee Kaushik , Natesan Srinivasan 
Published: May 2014

AbstractIn this article, we consider a class of singularly perturbed mixed parabolic‐elliptic problems whose solutions possess both boundary and interior layers. To solve these problems, a hybrid numerical scheme is proposed and it is constituted on a special rectangular mesh which consists of a layer resolving piecewise‐uniform Shishkin mesh in the spatial direction and a uniform mesh in the temporal direction. The domain under consideration is partitioned into two subdomains. For the spatial discretization, the proposed scheme is comprised of the classical central difference scheme in the first subdomain and a hybrid finite difference scheme in the second subdomain, whereas the time derivative in the given problem is discretized by the backward‐Euler method. We prove that the method converges uniformly with respect to the perturbation parameter with almost second‐order spatial accuracy in the discrete supremum norm. Numerical results are finally presented to validate the theoretical results.© 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1931–1960, 2014
Thigh fat and muscle each contribute to excess cardiometabolic risk in SouthAsians, independent of visceral adipose tissue
Authors: Eastwood Sophie V. , Tillin Therese , Wright Andrew , Mayet Jamil , Godsland Ian , Forouhi Nita G. , Whincup Peter , Hughes Alun D , Chaturvedi Nishi 
Published: May 2014

ObjectiveTo compare fat distribution and associations between fat depots and cardiometabolic traits in South Asians and Europeans.MethodsFive hundred and fourteen South Asians and 669 Europeans, aged 56‐86. Questionnaires, record review, blood testing, and coronary artery calcification scores provided diabetes and clinical plus subclinical coronary heart disease (CHD) diagnoses. Abdominal visceral (VAT) and subcutaneous adipose tissue, thigh subcutaneous adipose tissue (TSAT), intermuscular and intramuscular thigh fat and thigh muscle were measured by CT.ResultsAccounting for body size, South Asians had greater VAT and TSAT than Europeans, but less thigh muscle. Associations between depots and disease were stronger in South Asians than Europeans. In multivariable analyses in South Asians, VAT was positively associated with diabetes and CHD, while TSAT and thigh muscle were protective for diabetes, and thigh muscle for CHD. Differences in VAT and thigh muscle only partially explained the excess diabetes and CHD in South Asians versus Europeans. Insulin resistance did not account for the effects of TSAT or thigh muscle.ConclusionsGreater VAT and TSAT and lesser thigh muscle in South Asians contributed to ethnic differences in cardiometabolic disease. Effects of TSAT and thigh muscle were independent of insulin resistance.
Effect of temperature and volume on the tensile and adhesive properties of photocurable resins
Authors: Harding David R. , Goodrich Holly , Caveglia Aaron , Anthamatten Mitchell 
Published: May 2014

ABSTRACTKnowing the mechanical properties of UV‐curable resins at cryogenic conditions is important to ongoing fusion‐energy research and to emerging aerospace applications. The tensile and interfacial shear strengths of two commercially available UV‐curable resins were measured at room‐temperature and cryogenic conditions for both bulk and reduced (subnanoliter) specimen volumes. The tensile properties of cured specimens are remarkably sensitive to both testing temperature and specimen size. For one type of resin, the cold (−150 °C) tensile strength of subnanoliter specimens is ∼9× larger (179 ± 19 MPa) than bulk values at room temperature. The interfacial shear strength between SiC fibers and small volumes of resin volumes is comparable to the bulk, room‐temperature tensile strength, but it varies over a wide range at −150 °C (15–53 MPa). All resins were fully cured, and an analysis of fractured surfaces revealed microstructural features. The enhanced strength in microscopic specimens may be related to inhomogeneous stress fields that develop during cure. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 936–945
Burning Characteristics of Microcellular Combustible Objects Fabricated by a Confined Foaming Process
Authors: Yang Weitao , Li Yuxiang , Ying Sanjiu 
Published: May 2014

AbstractMicrocellular combustible objects for application of combustible case ammunition and caseless ammunition were fabricated by a confined pressure quenching foaming process using supercritical CO2 as foaming agent. The experimental results showed that the force constant (f) of objects obviously increased with an increasing RDX content and that the force constant of formulation with 55 % RDX is comparable to that of traditional felted case. Pressure histories, dp/dt‐t, and dynamic vivacity curves were investigated and compared by closed vessel tests. The influencing factors such as RDX content, expansion ratio, foaming temperature, sample size, and loading density were analysed. The results revealed that RDX content and expansion ratio significantly affected the burning properties, whereas the foaming temperature did not have obvious influence. Moreover, the burning behavior also changed with sample size and loading density.
Are unconfined hydrogen vapor cloud explosions credible?
Authors: Thomas James Kelly , Eastwood Craig , Goodrich Martin 
Published: May 2014

Owner/operators of chemical processing and petroleum refining sites often ask whether unconfined hydrogen vapor cloud explosions (VCEs) can actually occur. This question normally arises during the course of a consequence‐based facility siting study (FSS) or a quantitative risk assessment (QRA). While it is generally recognized that a hydrogen release within a process enclosure could lead to an explosion, the potential for an external hydrogen release to cause a VCE is not as widely recognized and is often questioned. This uncertainty appears to stem from the impression that a hydrogen release always ignites quickly and near the point of release such that a flammable cloud does not have time to develop prior to ignition and/or that a hydrogen release never produces a flammable cloud of any significant volume due to its positive buoyancy. Unfortunately, neither impression is correct. Hydrogen releases are actually susceptible to delayed ignition, and hydrogen releases can form significant flammable gas clouds near grade level. Unconfined hydrogen VCEs can and do occur. Furthermore, given the potential for rapid flame acceleration associated with hydrogen, the consequences of a hydrogen VCE can be severe. Consideration of such events in FSS and QRAs is, therefore, warranted.Prior accidental hydrogen VCEs are reviewed to establish that such events do occur. Selected hydrogen VCE tests are also discussed to establish the potential severity of such events. Moosemiller and Galindo [10th Global Congress on Process Safety, 2014 Annual AIChE Meeting, New Orleans, LA, March 30–April 2, 2014] reviewed the ignition characteristics of hydrogen relative to the potential for a delayed ignition, and only the conclusions from that article are presented here. Example dispersions, using both simplified dispersion and computational fluid dynamics methods, are presented to illustrate the flammable gas volumes that can be created by hydrogen release scenarios. Blast load predictions are presented to illustrate the range of loads that could result from a hydrogen VCE due to such a release. © 2014 American Institute of Chemical Engineers Process Saf Prog 34: 36–43, 2015
How is local material entropy production represented in a numerical model?
Authors: Gassmann Almut , Herzog Hans‐Joachim 
Published: May 2014

Numerical models of the atmosphere should fulfil fundamental physical laws. The second law of thermodynamics is associated with positive local entropy production and dissipation of available energy. In order to guarantee this positivity in numerical simulations, subgrid‐scale turbulent fluxes of heat, water vapour and momentum are required to depend on numerically resolved gradients in a unique way. The task of parametrization remains to deliver phenomenological coefficients.Inspecting commonly used parametrizations for subgrid fluxes, we find that some of them obey the second law of thermodynamics and some do not. The conforming approaches are Smagorinsky momentum diffusion, phase changes and sedimentation fluxes for hydrometeors. Conventional turbulent heat‐flux parametrizations do not conform with the second law. A new water‐vapour flux formulation is derived from the requirement of locally positive entropy production. The conventional and new water‐vapour fluxes are compared using high‐resolution radiosonde data. Conventional water‐vapour fluxes are wrong by up to 10% and exhibit a negative bias.Two numerical tests (the Boulder windstorm test case and a convective boundary‐layer experiment) are performed with the Icosahedral Nonhydrostatic model at the Institute for Atmospheric Physics (ICON–IAP). The experiments compare conventional and entropy‐consistent heat‐flux parametrizations. Both test cases indicate that negative thermal dissipation can occur for the conventional heat flux. Obviously, the additional energy made available by this negative dissipation to the resolved turbulence is later on dissipated by friction, so that the total dissipation is again comparable, at least for the boundary‐layer experiment.
Seismic performance and cost‐effectiveness of high‐rise buildings with increasing concrete strength
Authors: Aman Mwafy , Nadeem Hussain , Khaled El‐Sawy 
Published: May 2014

SummaryThe relationship between the seismic performance and economics of high‐rise buildings when designed to different material strengths is investigated in this paper. To represent the modern high‐rise construction, five 60‐story reinforced concrete buildings with varying concrete strengths, ranging from 45 MPa to 110 MPa, are designed and detailed to fine accuracy keeping almost equal periods of vibration. Detailed fiber‐based simulation models are developed to assess the relative seismic performance of the reference structures using incremental dynamic analyses and fragility functions. It is concluded that a considerable saving in construction cost and gain in useable area are attained with increasing concrete strength. The safety margins of high‐strength concrete in tall structures may exceed those of normal‐strength concrete buildings, particularly at high ground motion intensity levels. The recommendations of this systematic study may help designers to arrive at cost‐effective designs for high‐rise buildings in earthquake‐prone regions without jeopardizing safety at different performance levels. Copyright © 2014 John Wiley & Sons, Ltd.
Aerofoil optimization for vertical‐axis wind turbines
Authors: Ferreira Carlos Simão , Geurts Ben 
Published: May 2014

AbstractAn expression for the aerodynamic optimization of aerofoils for 2D lift driven vertical‐axis wind turbines is derived as a function of lift slope and drag. As lift slope is proportional to aerofoil thickness, the aerodynamic optimum is found in thick aerofoils, which are also structurally advantageous. Using a genetic optimization algorithm, the objective function is used to generate aerofoils whose performance in a vertical‐axis wind turbine is calculated using a potential flow solution of the induction field and 2D polars calculated with XFOIL. The results demonstrate power and structural gains. This approach can lead to reductions in rotor mass due to the thicker and thus stiffer aerofoils, without compromising aerodynamic performance. Copyright © 2014 John Wiley & Sons, Ltd.
Validation of boundary layer parameterization schemes in the Weather Research and Forecasting (WRF) model under the aspect of offshore wind energy applications—part II: boundary layer height and atmospheric stability
Authors: Krogsæter O. , Reuder J. 
Published: May 2014

AbstractFive different planetary boundary layer (PBL) schemes in the Weather Research and Forecasting (WRF) model have been tested with respect to their capability to model boundary layer parameters relevant for offshore wind deployments. For the year 2005, model simulations based on the YSU, ACM2, QNSE, MYJ and MYNN2 PBL schemes with WRF have been performed for the North Sea and validated against measurements from the FINO1 platform. In part I, the investigations had focused on the key parameters 100 m mean wind speed and wind shear in terms of the power‐law exponent. In part II, the focus is now set on the capability of the model to represent height and stability of the marine atmospheric boundary layer.Considerable differences are found among the PBL schemes in predicting the PBL height. A substantial part of this variation is explained by the use of different PBL‐height definitions in the schemes. The use of a standardized procedure in calculating the PBL height from common WRF output parameters, in particular the temperature gradient and the wind shear, leads to reduced differences between the different schemes and a closer correspondence with the FINO1 measurements. The study also reveals a very clear seasonal dependency of the atmospheric stability over Southern North Sea. During winter time, the marine atmospheric boundary layer is more or less neutral with several episodes of unstable periods. During spring and early summer, the occurrence of periods with very stable stratification becomes dominant with stable conditions up to 40–45% of the time when warm continental air is advected from the South. In general, the results of part II confirm again that the MYJ scheme performs slightly better than the others and can therefore be suggested as first choice for marine atmospheric boundary layer simulations without a priori information of atmospheric stability in the region of interest. Copyright © 2014 John Wiley & Sons, Ltd.
Influence of a Second Cation (M = Ca2+, Mg2+) on the Phase Evolution of (BaxM1–x)F2 Starting from Amorphous Deposits
Authors: Mu Xiaoke , Sigle Wilfried , Bach Andreas , Fischer Dieter , Jansen Martin , van Aken Peter A. 
Published: May 2014

AbstractA second type of cation (Mg2+, Ca2+) was introduced into BaF2 by low‐temperature atomic beam deposition. The structure evolution from low‐temperature (–150 °C) amorphous deposits to high‐temperature (< 1000 °C) annealed crystalline phases was studied by in‐situ transmission electron microscopy and X‐ray diffraction. Amorphous (Ba0.5, Ca0.5)F2 crystallizes in a first step to metastable solid solution phase (fluorite‐type), which then decomposes into the pure phases of CaF2 and BaF2 at higher temperature. The crystallization behavior of amorphous (BaxMg1–x)F2 is completely different. When the Mg/Ba atomic ratio is around 1:1, the mixture transforms to the ternary compound BaMgF4 at annealing, and no decomposition occurs by further heating up to 1000 °C. When the Ba concentration is below 15 % in atomic ratio (x < 0.15), the mixture forms a solid solution phase (rutile type) with the lattice expanded by +1 % compared to rutile type MgF2. The difference between the phase evolutions of the two mixture systems is discussed.
Three New Coordination Compounds with Neodymium Based on Tetrazole Containing Carboxylic Acid Ligands
Authors: Zou Jian‐Hua , Zhu Da‐Liang , Li Fei‐Fei , Li Fu‐Song , Wu He , Li Qiao‐Yun , Yang Gao‐Wen , Zhang Ping , Miao Yun‐Xia , Xie Jian 
Published: May 2014

AbstractReactions of three tetrazole containing carboxylic acid ligands, namely, Hpztza, Htzpya, and Hpytza [Hpztza = 5‐(2‐pyrazinyl)tetrazole‐2‐acetic acid, Htzpya = 3‐(5‐tetrazolyl)pyridine‐1‐acetic acid, Hpytza = 5‐(3‐pyridyl)tetrazole‐2‐acetic acid] with NdCl3·6H2O under hydrothermal conditions, afforded the complexes [Nd(pztza)2(H2O)6]·pztza·3H2O (1), [Nd2(tzpya)2(H2O)12]Cl4·2H2O (2), and [Nd(pytza)2Cl(H2O)2] (3). The compounds were structurally characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. X‐ray diffraction analyses revealed that compound 1 displays a mononuclear structure, 2 shows a dinuclear structure, and 3 features a 1D polymeric chain structure via pytza as linker. Furthermore, the luminescent properties investigated at room temperature in the solid state show that compound 2 has an obvious decrease in its luminescence, when compared to the ligand.