bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of stable α‐helices using global sequence optimization
Authors: Petukhov Michael , Tatsu Yoshiro , Tamaki Kazuyo , Murase Sachiko , Uekawa Hiroko , Yoshikawa Susumu , Serrano Luis , Yumoto Noboru 
Published: February 2009

AbstractThe rational design of peptide and protein helices is not only of practical importance for protein engineering but also is a useful approach in attempts to improve our understanding of protein folding. Recent modifications of theoretical models of helix‐coil transitions allow accurate predictions of the helix stability of monomeric peptides in water and provide new possibilities for protein design. We report here a new method for the design of α‐helices in peptides and proteins using AGADIR, the statistical mechanical theory for helix‐coil transitions in monomeric peptides and the tunneling algorithm of global optimization of multidimensional functions for optimization of amino acid sequences. CD measurements of helical content of peptides with optimized sequences indicate that the helical potential of protein amino acids is high enough to allow formation of stable α‐helices in peptides as short as of 10 residues in length. The results show the maximum achievable helix content (HC) of short peptides with fully optimized sequences at 5 °C is expected to be ∼70–75%. Under certain conditions the method can be a powerful practical tool for protein engineering. Unlike traditional approaches that are often used to increase protein stability by adding a few favorable interactions to the protein structure, this method deals with all possible sequences of protein helices and selects the best one from them. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Alloy softening in a martensitic stainless steel
Authors: Gupta C. , Chakravartty J. K. 
Published: February 2009

AbstractA study of the tensile flow behavior in the microstrain region of a martensitic stainless steel within the temperature range 77–273 K has been carried out. The ductility and work hardening in the low‐temperature region were found to be significantly larger than those of the ambient at temperatures where alloy softening was taking place. Thermal‐activation analysis of data has attributed the low‐temperature deformation behavior to the operation of the Peierls mechanism. While the Dorn–Rajnak model was found to fit the data, the observed alloy softening was attributed to the operation of an intrinsic mechanism that promoted the double‐kink formation on dislocations within a limited temperature range below ambient. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light soaking effect on photocurrent collection in (Zn,Mg)O/Cu(In,Ga)Se2 solar cells
Authors: Minemoto Takashi , Hori Hiroaki , Takakaura Hideyuki 
Published: February 2009

AbstractThe metastable behaviour, so‐called light soaking (LS) effect, on (Zn,Mg)O (ZMO)/Cu(In,Ga)Se2 (CIGS) solar cells with controlled conduction band offset (CBO) values of the ZMO/CIGS layers was characterized. When the conduction band of ZMO is higher than that of CIGS, which creates the notch of the ZMO/CIGS interface in the conduction band, metastable current‐voltage curves were observed. The metastability becomes prominent with increasing the CBO value. Quantum efficiency measurements before and after the LS revealed that the LS effect was mainly originated by the metastability in the photocurrent collection which influenced by the notch acting as a barrier for photo‐generated electrons in the CIGS layer. The model for the LS effect is discussed with simulated energy band diagrams. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cu(In,Ga)S2 films prepared by two‐stage evaporation on ZnO coated substrates
Authors: Kaigawa R. , Morimoto A. , Funahashi K. , Fujie R. , Wada T. , Sasaki M. , Merdes S. , Klenk R. 
Published: February 2009

AbstractWe have prepared Cu(In,Ga)S2 films with an almost homogeneous Ga depth distribution using the two‐stage multi‐source evaporation process on soda lime glass (SLG) substrates with one of three different kinds of back contact: Mo(1000nm), ZnO(500nm), and Mo(30nm)/ZnO(500nm), respectively. We have investigated the depth profiles of Zn and Na (diffused from SLG) in Cu(In,Ga)S2 films by secondary ion mass spectroscopy (SIMS) and compare them to those in films prepared by single stage co‐evaporation. The efficiencies are higher on Mo/ZnO than they are on ZnO. It was observed by SIMS that the amount of Zn in Cu(In,Ga)S2 on Mo/ZnO is lower than it is in Cu(In,Ga)S2 on ZnO. The obtained efficiencies are generally higher with two‐stage evaporation than with single stage co‐evaporation. The Na concentration in Cu(In,Ga)S2 prepared by two‐stage evaporation is two orders of magnitude higher than in single stage co‐evaporated films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of Sn‐doped and Sn:Ce‐codoped CaAl2S4 and application to white light emitting phosphor
Authors: Sorimachi Hiroshi , Ohta Hitoshi , Tanaka Kunihiko , Uchiki Hisao 
Published: February 2009

AbstractSn‐doped CaAl2S4 polycrystals and single crystals were synthesized by solid state reaction and chemical transport reaction method, respectively. They showed broad photoluminescence (PL) spectra in the visible region under the ultraviolet excitation and their luminescence color was pale yellow under the excitation at 325 nm. Three excitation bands at 3.67, 3.80, and 3.91 eV and three emission bands at 1.75, 1.93, and 2.15 eV were observed in photoluminescence excitation and PL spectra at 16 K. These bands were attributed to Sn ions which formed Tl+‐type impurity center. For the application to white LED, Ce was co‐doped into CaAl2S4:Sn polycrystals to enhance blue emission. As a result, Sn (0.5 mol%) and Ce (0.5 mol%) co‐doped CaAl2S4 polycrystals showed white luminescence with chromatic coordinates of (0.393, 0.392) and (0.364, 0.343) under the excitation at 325 and 330 nm, respectively. The highest quantum efficiency of 43% was obtained for Sn (0.1 mol%) and Ce (0.5 mol%) co‐doped CaAl2S4 polycrystals under 320 nm excitation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of Ge and P codoped p ‐type CuInS2 bulk crystals
Authors: Kato Takamasa , Yamaguchi Hiroshi , Muranaka Tsutomu , Nabetani Yoichi , Matsumoto Takashi 
Published: February 2009

AbstractCodoping of Ge and P into CuInS2 was carried out in order to grow p ‐type CuInS2 bulk crystals reproducibly in the S‐poor alloy composition region. The codoping condition for p ‐type crystal growth was made clear for the growth temperatures of 850 and 900 °C. The electrical and photoluminescence properties of codoped p ‐type crystals were also studied. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependence of excitonic emission in CuInSe2
Authors: Yakushev M. V. , Martin R. W. , Mudryi A. V. 
Published: February 2009

AbstractRadiative recombination processes in CuInSe2 (CIS) single crystals grown by the vertical Bridgman technique were studied using photoluminescence (PL) and reflectance (RF) spectroscopies at temperatures from 4.2 to 60 K, and excitation intensity from 0.6 to 30 W/cm2. Study of the quenching parameters of the A and B free‐ and first three bound‐excitons (M1, M2 and M3) in high‐quality CuInSe2 single crystal leads to estimates for the binding energy of the A (7.7 meV) and B (7.9 meV) free excitons as well as dissociation energies for the M1, M2 and M3 bound‐excitons. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multi‐platform observations of a springtime case of Bodélé and Sudan dust emission, transport and scavenging over West Africa
Authors: Flamant C. , Lavaysse C. , Todd M. C. , Chaboureau J.‐P. , Pelon J. 
Published: February 2009

AbstractThe structure of the Saharan air layer over Niger and Benin during a major springtime dust event from the Bodélé region and Sudan is investigated using airborne lidar and dropsonde measurements. Aircraft operations were conducted on 13 and 14 June 2006, within the framework of the African Monsoon Multidisciplinary Analysis Special Observing Period. Complementary ground‐based and satellite observations, as well as European Centre for Medium‐range Weather Forecasts analyses are used to investigate the regional aspects of emission, transport and deposition in the period from 9 to 14 June 2006, to provide a framework for the interpretation of the airborne measurements. The study details the transport patterns of dust from eastern Saharan sources towards the southwest in the springtime, and highlights the role of the intertropical discontinuity and the Darfur mountains in injecting the aerosols from Bodélé and Sudan, respectively, over the monsoon flow, and in the African easterly jet (AEJ) region. It also illustrates the impact of the daily variability of the emissions in the source regions on the dust load advected westward by the AEJ and observed over Benin. The impact of a mesoscale convective system (MCS) on the dust load and vertical distribution observed over Benin and southern Niger was also investigated, nearly 12 hours after its passage over Benin. The only discernible impact on the dust distribution is observed to be associated with widespread subsidence in the wake of the MCS, over northern Benin and Niger. Wet scavenging related to convective or stratiform rain could not be observed, as processed air masses were replaced by fresh dust transported in the upper Saharan air layer by the AEJ. Over southern Benin, the dust distribution appeared to be mostly controlled by processes affecting the planetary boundary layer upstream, i.e. over Nigeria or Chad. Because springtime dust from remote eastern sources (such as observed in this case) is mainly transported into the AEJ, it could impact on the radiation budget in the AEJ region, thereby possibly modifying the West African weather at the synoptic scale. Copyright © 2009 Royal Meteorological Society
Comment on ‘Can multi‐model combination really enhance the prediction skill of probabilistic ensemble forecasts?’
Authors: Weigel A. P. , Bowler N. E. 
Published: February 2009

AbstractThis note refers to the study of Weigel et al. (2008), where the success of multi‐model ensemble combination has been evaluated with a Gaussian stochastic toy model. The authors concluded that multi‐models can outperform the best participating single models, but only if the single model ensembles are under‐dispersive. Here we introduce two improved versions of the toy model of Weigel et al. For one of these models the combination of well‐dispersed (i.e. reliable) forecasts can improve the prediction skill, but for the other model this possibility is excluded. It is argued that, for normally distributed variables, the first model may be applicable in the context of short‐ and medium‐range forecasting, but the latter may be more appropriate to seasonal forecasting. Copyright © Royal Meteorological Society and Crown Copyright, 2009.
Radiative transfer validation study from the European Aqua Thermodynamic Experiment
Authors: Newman Stuart M. , Knuteson Robert. O. , Zhou Daniel K. , Larar Allen. M. , Smith William L. , Taylor Jonathan P. 
Published: February 2009

AbstractThe European AQUA Thermodynamic Experiment (EAQUATE) brought together collocated hyperspectral measurements from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite, as well as three airborne interferometers operating in the troposphere and stratosphere. Simultaneous observations of temperature, water vapour and trace gases have been used to constrain the atmospheric state, for validation of radiometric accuracy and radiative transfer modelling. The close agreement of observations with model spectra, in the 800–1200 cm−1 region, indicates that the accuracy of modelling AIRS spectra is sufficient for beneficial use of the data in operational weather forecasting. The variability of atmospheric water vapour was found to be a fundamental constraint in the modelling of the 1400–1600 cm−1 region, emphasising the requirement for a high density of observations in future validation campaigns. Copyright © Royal Meteorological Society and Crown Copyright, 2009.
Direct intramolecular gas‐phase transfer reactions during fragmentation of sildenafil and thiosildenafil analogs in electrospray ionization mass spectrometry
Authors: Reepmeyer John C. 
Published: February 2009

AbstractA study is made of the mass spectral fragmentation pathways of sildenafil, thiosildenafil, and analogous compounds. A prominent gas‐phase reaction that occurs during collision‐induced dissociation (CID) of thiosildenafil compounds is the transfer of an alkyl group from the piperazine nitrogen atom to the sulfur atom of the thiocarbonyl group. This phenomenon is clearly demonstrated through a comparison of electrospray ionization mass spectral fragmentation patterns of four sildenafil‐type compounds and three related thiosildenafil derivatives. Molecular modeling and fragmentation patterns support a direct intramolecular alkyl transfer mechanism rather than an ion‐neutral complex mechanism. CID of thiohydroxyhomosildenafil results in a facile hydroxyethyl migration to the sulfur atom followed by a second intramolecular reaction to form a spiro‐1,3‐oxathiolane ring, which fragments in two directions to generate both carbonyl and thiocarbonyl product ions from this thiocarbonyl compound. While methyl migration to the thiocarbonyl sulfur atom of thiosildenafil is dominant, methyl migration to the carbonyl oxygen atom of sildenafil may occur to a small extent. Published in 2008 by John Wiley & Sons, Ltd.
Electrochemical properties of niosomes‐modified Au electrode and its interaction with 1‐anilino‐8‐naphthalene‐sulfonate
Authors: Yang Chang‐Ying , Dai Zhong‐Xu , Li Xin , Rong Fan‐Chong 
Published: February 2009

AbstractThe gold electrode was modified by noisomes, prepared by sonicating the mixed solution of PEG 6000/Tween 80/Span 80/H2O. Electrochemical cyclic voltammetry (CV) and impedance spectroscopy (EIS) were performed for characterizing the modification. The construction of multilayer films of octadecanethiol (ODT)‐niosomes had almost no pinholes, which elicited that niosomes‐coated electrode through ODT assembly was more effective immobilization compared to direct modification method. A large semicircle formation in the entire range of frequency indicated the complete electron‐transfer control for the redox reaction, implying a perfect blocking behavior. The Nyquist plot was consisting of two depressed semicircles after storage for 36 h in air, which implied a progressive and uniform construction manner, as expected for porous coatings. The modified electrode was used to investigate the interaction between 1‐anilino‐8‐naphthalene‐sulfonate (ANS) and noisomes. It was found that the low‐frequency semicircular arcs increase in diameter, indicating that the increase in the resistance Rp attributed mainly to the niosomes/solution interface. It was due to the binding of ANS to the niosomes‐modified electrode surface, exhibited against diffusing species through the pores. Copyright © 2009 John Wiley & Sons, Ltd.
Focused ion beam irradiation—morphological and chemical evolution in PMMA
Authors: Kochumalayil J. J. , Meiser A. , Soldera F. , Possart W. 
Published: February 2009

AbstractFor poly(methyl methacrylate) (PMMA) as a representative of amorphous thermoplastic polymers, the milling effects, and the chemical changes due to ion bombardment with a focused ion beam (FIB) at normal incidence are studied with scanning force microscopy (SFM), scanning electron microscopy (SEM)/energy dispersive X‐ray (EDX), and infrared (IR) spectroscopy for varying conditions of Ga+ treatment, including the effect of partial water pressure. Stopping and Range of Ions in Matter (SRIM) simulation results for 30 keV Ga+ at normal incidence show that the zone of primary ion–polymer interaction extends ca 100 nm into the PMMA. Accordingly, this interaction region is much wider than the original beam diameter. The width of the region where the recoiled ions interact strongly with the polymer chains is larger. Secondary processes, such as fragment diffusion and phonon transport, are expected to extend even farther into the polymer. SEM and SFM reveal distinct topologies of areas milled without or in presence of water vapour. Water vapour–assisted FIB milling produces more roughness and defects. The infrared attenuated total reflection spectroscopy (IR‐ATR) spectra indicate that ion milling in PMMA damages methacrylate side groups in particular. In contrary to metals, an increase in the degree of milling is found when the beam spot overlap parameter increases. Copyright © 2009 John Wiley & Sons, Ltd.
Correcting for multivariate measurement error by regression calibration in meta‐analyses of epidemiological studies
Authors:   Fibrinogen Studies Collaboration
Published: February 2009

AbstractWithin‐person variability in measured
values of multiple risk factors can bias their associations with disease. The multivariate regression calibration (RC) approach can correct for such measurement error and has been applied to studies in which true values or independent repeat measurements of the risk factors are observed on a subsample. We extend the multivariate RC techniques to a meta‐analysis framework where multiple studies provide independent repeat measurements and information on disease outcome. We consider the cases where some or all studies have repeat measurements, and compare study‐specific, averaged and empirical Bayes estimates of RC parameters. Additionally, we allow for binary covariates (e.g. smoking status) and for uncertainty and time trends in the measurement error corrections. Our methods are illustrated using a subset of individual participant data from prospective long‐term studies in the Fibrinogen Studies Collaboration to assess the relationship between usual levels of plasma fibrinogen and the risk of coronary heart disease, allowing for measurement error in plasma fibrinogen and several confounders. Copyright © 2009 John Wiley & Sons, Ltd.
Nanoparticles for Optical Molecular Imaging of Atherosclerosis
Authors: Douma Kim , Prinzen Lenneke , Slaaf Dick W. , Reutelingsperger Chris P. M. , Biessen Erik A. L. , Hackeng Tilman M. , Post Mark J. , van Zandvoort Marc A. M. J. 
Published: February 2009

AbstractMolecular imaging contributes to future personalized medicine dedicated to the treatment of cardiovascular disease, the leading cause of mortality in industrialized countries. Endoscope‐compatible optical imaging techniques would offer a stand‐alone alternative and high spatial resolution validation technique to clinically accepted imaging techniques in the (intravascular) assessment of vulnerable atherosclerotic lesions, which are predisposed to initiate acute clinical events. Efficient optical visualization of molecular epitopes specific for vulnerable atherosclerotic lesions requires targeting of high‐quality optical‐contrast‐enhancing particles. In this review, we provide an overview of both current optical nanoparticles and targeting ligands for optical molecular imaging of atherosclerotic lesions and speculate on their applicability in the clinical setting.magnified image
Coupled Ionic and Electronic Transport Model of Thin‐Film Semiconductor Memristive Behavior
Authors: Strukov Dmitri B. , Borghetti Julien L. , Williams R. Stanley 
Published: February 2009

AbstractThe memristor, the fourth passive circuit element, was predicted theoretically nearly 40 years ago, but we just recently demonstrated both an intentional material system and an analytical model that exhibited the properties of such a device. Here we provide a more physical model based on numerical solutions of coupled drift‐diffusion equations for electrons and ions with appropriate boundary conditions. We simulate the dynamics of a two‐terminal memristive device based on a semiconductor thin film with mobile dopants that are partially compensated by a small amount of immobile acceptors. We examine the mobile ion distributions, zero‐bias potentials, and current–voltage characteristics of the model for both steady‐state bias conditions and for dynamical switching to obtain physical insight into the transport processes responsible for memristive behavior in semiconductor films.
The neurokinin‐3 (NK3) and the neurokinin‐1 (NK1) receptors are differentially targeted to mesocortical and mesolimbic projection neurons and to neuronal nuclei in the rat ventral tegmental area
Authors: Lessard Andrée , Savard Martin , Gobeil Fernand , Pierce Joseph P. , Pickel Virginia M. 
Published: February 2009

AbstractTonic activation of neurokinin‐3 (NK3) receptors in dopamine neurons of the ventral tegmental area (VTA) has been implicated in the pathophysiology of schizophrenia. This psychiatric disorder is associated with a dysfunctional activity in VTA projection neurons that can affect cognitive function at the level of the medial prefrontal cortex (mPFC) as well as motor and motivational states controlled in part by mesolimbic output to the nucleus accumbens (Acb). To determine the relevant sites for NK3receptor activation within this neuronal network, we used confocal and electron microscopy to examine NK3receptors (Cy5; immunogold) and retrograde labeling of fluorogold (FG, FITC; immunoperoxidase) in the VTA of rats receiving either Acb or mPFC injections of FG. Comparison was made with neurokinin‐1 (NK1) receptors, which are also present, but less abundant then NK3receptors, in dopaminergic and GABAergic VTA neurons. There were no observable differences between NK3and NK1receptors in their primary locations in the cytoplasm and on the plasma membrane of VTA somata and dendrites with or without FG. Dendrites labeled with FG retrogradely transported from mPFC, however, contained more NK3or less NK1immunogold particles (plasmalemmal + cytoplasmic) then those retrogradely labeled following FG injection in the Acb. Moreover, only the NK3receptors were detected in neuronal nuclei in the VTA and in the nuclei of human HEK‐293T NK3‐transfected cells. The enrichment of NK3receptors in mesocortical projection neurons and nuclear distribution of these receptors may provide insight for understanding the selective antipsychotic effectiveness of NK3antagonists. Synapse 63:484–501, 2009. © 2009 Wiley‐Liss, Inc.
A hybrid genetic algorithm and optimality criteria method for optimum design of RC tall buildings under multi‐load cases
Authors: Li Gang , Lu Haiyan , Liu Xiang 
Published: February 2009

AbstractThis paper proposes a hybrid heuristic and criteria‐based method of optimum design that combines the advantages of both the genetic algorithm (GA) and the rigorously derived optimality criteria (OC) for structural optimum design of reinforced concrete tall buildings under multi‐load cases based on the current Chinese design codes. The entire optimum design procedure is divided into two parts: strength optimum design and stiffness optimum design, which are performed by the GA and the OC method, respectively. The optimum reinforcement detailing, which satisfies the strength, serviceability, ductility and other constraints related to the user‐specified rules and regulations in design codes, is achieved by constructing the data sets containing different available reinforcement bar diameter in a pre‐specified pattern. An adaptive feasible region technique is developed to improve the efficiency of GA. Finally, a practical frame‐shear‐wall structure (30‐storey) is optimized to illustrate the effectiveness and practicality of the proposed optimum design method. Copyright © 2009 John Wiley & Sons, Ltd.