bluuebunny/crossref_metadata_2025_split huggingface dataset:
35Cl NQR and X‐Ray Studies of Pentachloroethylstannate(IV) Salts
Authors: Storck Peter , Weiss Alarich 
Published: July 2012

AbstractThe 35CI NQR spectra of pentachloroethylstannate(IV) complex salts A2[(C2H5)SnCl5)] with four different cations A⊕ (A⊕ = Tetra‐ methylamnionium, [(CH3)4N]⊕ (I), Pyridinium, [CSHSNH]⊕ (II). Methylammonium, [CH3NH3]⊕ (III), and 4‐Picolinium, [4‐CH3 ‐ C5H4NH]⊕ (IV)) have been recorded and their crystal structures were determined. The compounds crystallize with a distorted K2PtCI6‐type structure ((I): space group C62h/c, a = 1408.9 pm, b = 1123.2 pm, c = 1332.7 pm, β = 90.94°, Z = 4; (II): space group C52h/c, a = 1618.8 pm, b = 744.6 pm, c = 1520.0 pm, β = 90.515°, Z = 4; (IV): space group Ct‐Pi, a = 1093.4 pm, b = 938.8 pm, c = 722.6 pm, α = 108.37°, β = 90.84', γ = 93.90, Z = 2 = (IV): space group D42‐P212121, a = 2181.1 pm, b = 1088.3 pm, c = 858.2 pm, Z = 4). The effects of the substitution of one Cl⊖ ligand within a SnCl2⊖6 octahedron by the stronger electron donor C2H⊖5 are: (a) The mean strength of all 5 Sn—Cl bonds is lowered. This is reflected by a decrease of the mean 35Cl NQR frequencies and an increase in Sn—Cl bond length compared with hexachlorostannates; (b) There exists a distinct cis and trans influence of the ethyl group. The Sn—Cl bonds in cis position to the ethyl group are highly weakened (cis‐weakening), while the trans effect is much smaller in magnitude and probably of opposite sign (trans‐strengthening). The influence of hydrogen bonds weakens Sn—Cl bonds in addition to cis‐weakening. A correlation of 35Cl NQR frequencies and Sn—Cl bond lengths shows a slope of —0.6 MHz/pm. The ethyl group is ordered in (II) and (III), disordered in (IV) and rotates in (I). In (I) a phase transition at 180 K could be detected by 35Cl NQR and DTA, the reason of which may be a freezing in of the ethyl group rotation.
Thermodynamical expectation values in restrained equilibria, dielectrical and electro‐optical relaxation strengths, and the Kerr effect of PMMA
Authors: Gallenkamp Uwe , Jungnickel Bernd‐J. 
Published: July 2012

AbstractThe Kerr effect of PMMA is composed of several relaxation steps which differ remarkably in their time scales. The relative strengths of these steps are quite different after application and removal of the electric field, respectively. In the present paper, general equations for such relaxation step strengths are derived considering that occasionally certain molecular motional modes are frozen in at a given observation temperature and, therefore, only restrained thermodynamic equilibria can be attained. The results are also applicable to any other, in case non‐linear, relaxation phenomenon. By means of the derived equations, the contributions of every relaxation step to the dielectric susceptibility and the Kerr constant are calculated, taking into account also possible orientation correlations between the relaxing structural units. With these relations, in turn, the dielectric permittivities and the Kerr constants of PMMA can be calculated. The derived equations, moreover, predict a peculiar cross‐over electro‐optical transient relaxation behaviour for molecules with suitable conformational degrees of freedom.
Electrochemical in‐situ investigations on polycrystalline gold electrodes with oscillating quartz crystals: Deposition and bulk diffusion of palladium
Authors: Stöckel Wolfgang , Schumacher Rolf 
Published: July 2012

AbstractThe electrochemical deposition of palladium on polycrystalline gold substrates was followed in the UPD range and under conditions where massive metal deposition occurs. These processes were studied by means of in‐situ microweighing, cyclic voltammetry and the registration of frequency and current with time. In addition, the diffusion kinetics of palladium into the gold substrate was studied under UPD conditions. The latter process leads to alloy formation. The electrosorption valency γ for palladium adsorbates was determined to be γ = 1.8. The apparent diffusion coefficient D of palladium into the gold electrode yields D ≈ 10−17 cm2/s for the conditions applied here.
The integrated intensities of chemically‐exchanging vibrational bands as given by the Bloch equations
Authors: Wood Kurt A. , Strauss Herbert L. 
Published: July 2012

AbstractRecent predictions of dramatic integrated intensity changes in vibrational bands undergoing collapse due to chemical exchange are the result of improper normalization factors inserted into the Bloch‐equation treatment. For the correct form of the Bloch equations, integrated intensity is approximately conserved. However, even in this case the problems inherent in applying the Bloch equations to vibrational systems remain.
Rates and mechanisms of the reactions of ethanol and propanol with fluorine and chlorine atoms
Authors: Khatoon T. , Edelbüttel‐Einhaus J. , Hoyermann K. , Wagner H. Gg. 
Published: July 2012

AbstractThe reactions of C2H5OH (1), C2H5OD (2), C2D5OD (3), 1‐C3H7OH (4), 2‐C3H7OH (5), 2‐C3H7OD (6) with F atoms and the reactions of C2H5OH (7), 1‐C3H7OH (8), 1‐C3H7OD (9), 2‐C3H7OD (10) with Cl atoms have been studied in a discharge flow reactor and a Laval nozzle reactor at room temperature and at pressures of a few mbar. Samples of the reaction mixtures were withdrawn continuously by a molecular beam device and analyzed by a mass spectrometer. The rates of the reactions were measured relative to the standard reactions C2H6 + F (0) and C2H6 + Cl (00) yielding k1/k0 = 1.06, k2/k0 = 1.25, k3/k0 = 1.20, k4/k0 = 1.26, k5/k0 = 1.06, k6/k0 = 1.20, k7/k00 = 2, k9/k00 = 4. For the reactions of F atoms with alcohols the probability of attack at one of the alkyl H atoms was found to be five times less than at the hydroxyl H atom site. For the reactions of Cl atoms with alcohols no abstraction from the OH group was observed, the abstraction from the alkyl groups follows the thermodynamically favoured route by forming mainly secondary radicals.
Association between weight gain during pregnancy and neural tube defects and gastroschisis in offspring
Authors: Yang Wei , Carmichael Suzan L. , Tinker Sarah C. , Shaw Gary M. ,   the National Birth Defects Prevention Study
Published: July 2012

AbstractBACKGROUNDLimited information is available about the association of maternal weight gain during pregnancy and birth defects. The objective of this study was to investigate the association of maternal weight gain with neural tube defects (NTDs) and gastroschisis among offspring.METHODSWe used data from the National Birth Defects Prevention Study, an ongoing multicenter, population‐based, case‐control study. Mothers of cases and controls were interviewed by telephone. Analyses included 255 anencephaly, 577 spina bifida, 648 gastroschisis cases, and 5587 controls with deliveries from 1999 to 2005. After subtracting birth weight, the associations of total and average weekly weight gain (kg) with each phenotype were estimated, stratified by gestational age (<37 vs. ≥37 weeks) and adjusted for relevant covariates.RESULTSAmong deliveries <37 weeks gestation, mothers of infants with anencephaly and spina bifida had lower weight gains compared to control mothers; no association between weight gains and gastroschisis was observed. Among deliveries ≥37 weeks, mothers of infants with anencephaly had lower weight gains during pregnancy; a similar association was not observed for spina bifida; mothers of infants with gastroschisis were twice as likely to have weight gains in the highest quartile. Stratification by maternal age (gastroschisis) or body mass index (BMI) or race/ethnicity (all phenotypes) did not alter odds ratio estimates.CONCLUSIONAltered weight gain during pregnancy may be a consequence of carrying an NTD/gastroschisis affected fetus or a marker for underlying factors common to the etiology of these birth defects. It is possible that whatever mechanisms influence weight gain may also influence the development of NTDs and gastroschisis, but in opposite directions.
High‐Performance Liquid Chromatographic Enantioseparation of Unusual Isoxazoline‐Fused 2‐Aminocyclopentanecarboxylic Acids on (+)‐(18‐Crown‐6)‐2,3,11,12‐Tetracarboxylic Acid‐Based Chiral Stationary Phases
Authors: Sipos László , Ilisz István , Aranyi Anita , Gecse Zsanett , Nonn Melinda , Fülöp Ferenc , Hyun Myung Ho , Péter Antal 
Published: July 2012

ABSTRACTThe enantiomers of four unusual isoxazoline‐fused 2‐aminocyclopentanecarboxylic acids were directly separated on chiral stationary phases containing (+)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid as chiral selector. The nature of the alcoholic modifier (MeOH, EtOH, IPA) exerted a great effect on the retention, whereas the selectivity and resolution did not change substantially. Two types of dependence of retention on alcohol content were detected: k1 increased continuously with increasing alcohol content or a U‐shaped retention curve was observed. A comparison of the chromatographic data obtained with HCOOH, AcOH, TFA, HClO4, H2SO4, or H3PO4 as acidic modifier at a constant concentration demonstrated that in most cases, larger k values were obtained on the application of AcOH or HCOOH, and an increase of the acid content resulted in a decrease of retention. Some mechanistic aspects of the chiral recognition process are discussed with respect to the structures of the analytes and selector. The sequence of elution of the enantiomers was determined in all cases. Chirality 24:817‐824, 2012. © 2012 Wiley Periodicals, Inc.
Layout optimization method for magnetic circuit using multistep utilization of genetic algorithm combined with design space reduction
Authors: Okamoto Yoshifumi , Tominaga Yusuke , Sato Shuji 
Published: July 2012

AbstractLayout optimization with ON/OFF information of magnetic material in finite elements is one of the most attractive tools in the initial conceptual and practical design of electrical machinery for engineers. Heuristic algorithms based on random search allow engineers to define general‐purpose objects. However, there are many iterations of finite element analysis, and it is difficult to achieve a practical solution without island and void distribution by using a direct search method, such as simulated annealing (SA), genetic algorithm (GA), and so on. This paper presents a layout optimization method based on GA. The proposed method can arrive at a practical solution by means of multistep utilization of the GA, and the convergence speed is considerably improved by using it in combination with reduction of the design space. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(3): 19‐30, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22290
KSRP: A checkpoint for inflammatory cytokine production in astrocytes
Authors: Li Xuelin , Lin Wei‐Jye , Chen Ching‐Yi , Si Ying , Zhang Xiaowen , Lu Liang , Suswam Esther , Zheng Lei , King Peter H. 
Published: July 2012

AbstractChronic inflammation in the central nervous system (CNS) is a central feature of many neurodegenerative and autoimmune diseases. As an immunologically competent cell, the astrocyte plays an important role in CNS inflammation. It is capable of expressing a number of cytokines such as tumor necrosis factor alpha (TNF‐α) and interleukin‐1 beta (IL‐1β) that promote inflammation directly and through the recruitment of immune cells. Checkpoints are therefore in place to keep tight control over cytokine production. Adenylate/uridylate‐rich elements (ARE) in the 3′ untranslated region of cytokine mRNAs serve as a major checkpoint by regulating mRNA stability and translational efficiency. Here, we examined the impact of KH‐type splicing regulatory protein (KSRP), an RNA binding protein which destabilizes mRNAs via the ARE, on cytokine expression and paracrine phenotypes of primary astrocytes. We identified a network of inflammatory mediators, including TNF‐α and IL‐1β, whose expression increased 2 to 4‐fold at the RNA level in astrocytes isolated from KSRP−/− mice compared to littermate controls. Upon activation, KSRP−/− astrocytes produced TNF‐α and IL‐1β at levels that exceeded control cells by 15‐fold or more. Conditioned media from KSRP−/− astrocytes induced chemotaxis and neuronal cell death in vitro. Surprisingly, we observed a prolongation of half‐life in only a subset of mRNA targets and only after selective astrocyte activation. Luciferase reporter studies indicated that KSRP regulates cytokine gene expression at both transcriptional and post‐transcriptional levels. Our results outline a critical role for KSRP in regulating pro‐inflammatory mediators and have implications for a wide range of CNS inflammatory and autoimmune diseases. © 2012 Wiley Periodicals, Inc.
Sex‐related differences of cAMP‐specific PDE4B3 mRNA in oligodendrocytes following systemic inflammation
Authors: Johansson Emily M. , Sanabra Cristina , Mengod Guadalupe 
Published: July 2012

AbstractSex‐related differences have been observed in the incidence and severity of several neurological diseases and in sepsis in humans. Cyclic adenosine monophosphate (cAMP) has been shown to play an important role in modulating the inflammatory environment during neuroinflammation and importantly in protecting myelin from excitotoxic cell death. Considering the sexual dimorphism in the functional properties of oligodendrocytes and the importance of a systemic inflammation in the progression of multiple sclerosis, we focused on identifying possible sex‐related differences in the alterations previously reported for the two phosphodiesterase4B (PDE4B) splice‐variants (PDE4B2 and PDE4B3) mRNA expression during innate neuroinflammation. PDE4A, PDE4B, and PDE4D are present in oligodendrocytes and we have previously reported that PDE4B3 mRNA is readily expressed in both oligodendrocytes and neurons. In this study, we analyzed the influence of an intraperitoneal lipopolysaccharide injection on the distribution pattern and expression levels of the PDE4B mRNA splicing variants in both male and female mice brains. Clear differences were observed in PDE4B2 and PDE4B3 mRNA expression levels in males compared with females in a time‐dependent manner. Furthermore, we observed that the clear downregulation of PDE4B3 mRNA was reflected in a lower percentage of oligodendrocytes positive for this transcript which correlated with a decrease in inducible cAMP early repressor expression in female corpus callosum. © 2012Wiley Periodicals, Inc.
Determination of synthetic wind functions for estimating open water evaporation with Computational Fluid Dynamics
Authors: Vidal‐López P. , Martínez‐Alvarez V. , Gallego‐Elvira B. , Martín‐Górriz B. 
Published: July 2012

AbstractA computational fluid dynamics (CFD)‐based methodology is proposed to derive convective mass‐transfer coefficients (wind functions) that are required for estimating evaporation of water bodies with the mass‐transfer method. Three‐dimensional CFD was applied to model heat transfer in two water bodies: a Class‐A tank evaporimeter and an on‐farm artificial pond. The standard k–ɛ model assuming isotropic turbulence was adopted to describe turbulent heat transport, whereas the heat and mass transfer analogy was assumed to derive the wind functions.The CFD‐derived wind functions were very similar to those empirically derived from the experimental water bodies. The evaporation rates calculated with the synthetic wind functions were in good agreement with hourly and daily evaporation measurements for the tank and pond, respectively. The proposed CFD‐approach is generalisable and cost effective, because it has low input data requirements. Besides, it provides additional capability of modelling the spatial distribution of the evaporation rate over the water surface. Although the application of CFD to water bodies evaporation modelling is still in development, it looks very promising. Copyright © 2012 John Wiley & Sons, Ltd.
A reliable and efficient first principles‐based method for predicting pKa values. 4. organic bases
Authors: Zhang Shuming 
Published: July 2012

AbstractThe ionization (dissociation) constant (pKa) is one of the most important properties of a drug molecule. It is reported that almost 68% of ionized drugs are weak bases. To be able to predict accurately the pKa value(s) for a drug candidate is very important, especially in the early stages of drug discovery, as calculations are much cheaper than determining pKa values experimentally. In this study, we derive two linear fitting equations (pKa = a × ΔE + b; where a and b are constants and ΔE is the energy difference between the cationic and neutral forms, i.e., ΔE = Eneutral−Ecationic) for predicting pKas for organic bases in aqueous solution based on a training/test set of almost 500 compounds using our previously developed protocol (OLYP/6‐311+G**//3‐21G(d) with the the conductor‐like screening model solvation model, water as solvent; see Zhang, Baker, Pulay, J. Phys. Chem. A 2010, 114, 432). One equation is for saturated bases such as aliphatic and cyclic amines, anilines, guanidines, imines, and amidines; the other is for unsaturated bases such as heterocyclic aromatic bases and their derivatives. The mean absolute deviations for saturated and unsaturated bases were 0.45 and 0.52 pKa units, respectively. Over 60% and 86% of the computed pKa values lie within ±0.5 and ±1.0 pKa units, respectively, of the corresponding experimental values. The results further demonstrate that our protocol is reliable and can accurately predict pKa values for organic bases. © 2012 Wiley Periodicals, Inc.
Computational prediction of monosaccharide binding free energies to lectins with linear interaction energy models
Authors: Mishra Sushil Kumar , Sund Johan , Åqvist Johan , Koča Jaroslav 
Published: July 2012

AbstractThe linear interaction energy (LIE) method to compute binding free energies is applied to lectin‐monosaccharide complexes. Here, we calculate the binding free energies of monosaccharides to the Ralstonia solanacearum lectin (RSL) and the Pseudomonas aeruginosa lectin‐II (PA‐IIL). The standard LIE model performs very well for RSL, whereas the PA‐IIL system, where ligand binding involves two calcium ions, presents a major challenge. To overcome this, we explore a new variant of the LIE model, where ligand–metal ion interactions are scaled separately. This model also predicts the saccharide binding preference of PA‐IIL on mutation of the receptor, which may be useful for protein engineering of lectins. © 2012 Wiley Periodicals, Inc.
Comparison of three humanized mouse models for adoptive T cell transfer
Authors: Volk Andreas , Hartmann Sylvia , Muik Alexander , Geiß Yvonne , Königs Christoph , Dietrich Ursula , von Laer Dorothee , Kimpel Janine 
Published: July 2012

AbstractBackgroundHumanized mouse models for adoptive T cell transfer are important for preclinical efficacy and toxicity studies. However, common xenograft models using immunodeficient mice have so far failed to efficiently support the homing of human T cells to secondary lymphoid tissues.MethodsWe established a new mouse model for the adoptive transfer of genetically‐modified (gm) T cells using conditioned BALB/c mice. Conditioning involved cyclophosphamide injections, lethal irradiation and radioprotection with bone marrow from immunodeficient mice. We compared repopulation kinetics and the quality of grafts in these modified Trimera (mT3) mice with immunodeficient BALB/c Rag2−/− interleukin (IL)2 receptor gamma (rg) knockout (DKO) and NOD/LtSz‐scid IL2rg−/− (NSG) recipient mouse strains.ResultsDKO mice showed only marginal engraftment until onset of graft‐versus‐host disease, whereas mT3 and NSG were repopulated with comparable kinetics. However, T cell repertoire and human cytokine profiles suggest a xenoreactivity‐driven gm T cell expansion in mT3 mice, whereas NSG mice were characterized by an initial homeostatic proliferation. Morphological analysis revealed high levels of human gm T cell infiltration in the spleen and liver of all three mouse strains. However, mT3 mice provided the strongest homing of human gm T cells to mucosal sites. Additionally, mT3 mice were the only model with macroscopically visible superficial inguinal lymph nodes. These lymph nodes strongly supported the homing of gm T cells.ConclusionsIn the present study, we give proof‐of‐concept that wild‐type mice can accept gm T cell grafts while providing secondary lymphoid structures. Despite limitations, mT3 mice are a valid alternative for applications that specifically rely on improved secondary lymphoid structures. Copyright © 2012 John Wiley & Sons, Ltd.
Posttraumatic stress disorder and memory: Evidence of maladaptations to stressors
Authors: Ashby Erin L. , Cornelius Allen 
Published: July 2012

AbstractPeople with posttraumatic stress disorder (PTSD) are entering the workforce in record numbers as they discharge from the military and attempt to enter the civilian workforce. Understanding how PTSD affects the human mind will help organizations manage their employees more effectively by allowing supervisors to set up systems that compensate for deficits. PTSD appears to cause significant memory and attentional deficits; however, it is difficult to determine whether the attentional deficits contribute to the memory deficits. The current study used the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to examine the memory deficits separate from the attention difficulties in people with PTSD. Results demonstrated that PTSD severity correlated with attention issues, but not memory issues. The authors discuss these findings in terms of their clinical and organizational applications.
Horned grebe habitat use of constructed wetlands in Alberta, Canada
Authors: Kuczynski Eva C. , Paszkowski Cynthia A. , Gingras Bev A. 
Published: July 2012

AbstractWetland degradation has resulted in declines in populations of aquatic birds throughout North America. Horned grebe (Podiceps auritus), a migratory diving bird experiencing population decline, may benefit from wetland construction. We examined horned grebe use of borrow pits (ponds created during highway construction) in Alberta, Canada. Our goals were to document patterns of occurrence and breeding success of grebes on borrow pits and to determine if occupied and unoccupied sites differed in local habitat or landscape characteristics. In May 2003 and 2007, 330 constructed ponds were surveyed for horned grebes. We chose 100 occupied and 100 unoccupied ponds for additional surveys in 2007 and 2008, and collected habitat and landscape data for these sites. We used generalized linear mixed model and generalized linear model regression, coupled with Akaike's Information Criterion, to determine which environmental variables were most effective in explaining occurrence of horned grebes. The best model included all measured local and landscape habitat features. Horned grebes occurred on 36% of ponds in May 2003 and 2007, and chicks were produced on 74.5–81.3% of occupied ponds in 2007 and 2008. Grebes occupied larger ponds with more emergent and riparian vegetation and avoided ponds that supported beavers, contained human structures, and were primarily surrounded by forest within 1 km. On ponds with grebe pairs, chicks were produced more often on sites surrounded by more riparian vegetation. We conclude that the construction of small wetlands offers a promising means of increasing breeding habitat for horned grebes and present specific recommendations for breeding pond construction. © 2012 The Wildlife Society.