bluuebunny/crossref_metadata_2025_split huggingface dataset:
CNS response to a thermal stressor in human volunteers and rats may predict the clinical utility of analgesics
Authors: Borsook David , Pendse Gautam , Aiello‐Lammens Mathew , Glicksman Marcie , Gostic Julie , Sherman Seth , Korn Joshua , Shaw Marnie , Stewart Ken , Gostic Richard , Bazes Shelly , Hargreaves Richard , Becerra Lino 
Published: June 2007

AbstractfMRI was used to test the hypothesis that global brain activation following a stressor (a thermal stimulus) that activates multiple brain circuits in healthy subjects can predict which drugs have higher potential for clinical utility for neuropathic pain. The rationale is that a drug will modulate multiple neural circuits that are activated by the system‐specific stressor (e.g., pain). In neuropathic pain, some brain circuits have altered function, but most brain systems are “normal.” Thus, the manner in which a drug effect on neural circuits is modulated by the stressor may provide insight into the clinical utility based on the readout of brain activation in response to the stimulus. Six drugs with known clinical efficacy (or lack thereof) in treating neuropathic pain were selected and the CNS response to each drug in the presence or absence of a pain stimulus was examined. The present results suggest that it is possible to identify potentially effective drugs based on patterns of brain activation in healthy human subjects and indicate that CNS activity is a more sensitive measure of drug action than standard psychophysical measures of pain intensity. This approach was repeated in rats and showed that a similar fMRI paradigm segregates these drugs in a similar manner suggesting a potential “translational tool” in evaluating drug efficacy for neuropathic pain. The sensitivity of this paradigm using fMRI allows clinical screening in small groups of healthy subjects, suggesting it could become a useful tool for drug development as well as for elucidating the mechanisms of neuropathic disease and therapy. Drug Dev. Res. 68:23–41, 2007. © 2007 Wiley‐Liss, Inc.
Matrix metalloproteinase and aggrecanase generated aggrecan fragments: implications for the diagnostics and therapeutics of destructive joint diseases
Authors: Sumer Eren U. , Qvist Per , Tankó László B. 
Published: June 2007

AbstractThe degradation of extracellular matrix (ECM) components of articular cartilage is a hallmark of joint‐destructive diseases like osteoarthritis (OA) and rheumatoid arthritis (RA). A major component of the ECM is aggrecan, a proteoglycan, which is among the first matrix components to be degraded by the action of catabolic enzymes, increasingly expressed and activated during the inflammatory responses accompanying the aforementioned joint‐diseases. The two main families of enzymes are Matrix Metalloproteinases (MMPs) and aggrecanases, which both contribute to the degradation of the ECM, although their relative importance may vary between matrix components. Understanding the process of aggrecan degradation has crucial implications for improving the early diagnosis and monitoring of destructive joint‐diseases, as well as the therapeutic responses to disease‐modifying agents with potential chondroprotective effects. In the present review, we wish to provide an update on the emerging knowledge in the field obtained from ex vivo cartilage explants subjected to catabolic enzymes relevant for the pathogenesis of osteoarthritis (OA), as well as from synovial fluid of OA patients. In addition, we discuss the present status of specific immunochemical biomarker assays that were recently introduced to serve as diagnostic tools and emerging concepts of pharmacological interventions targeting the inhibition of aggrecan destruction, with the ultimate aim of decreasing the epidemiological burden of OA and rheumatoid arthritis (RA). Drug Dev Res 68:1–13, 2007. © 2007 Wiley‐Liss, Inc.
Mutual Influences of Ligands as Revealed by 2H NMR Shifts and the Angular Overlap Model Parameters: trans‐ and cis‐[CrX2(N)4]‐Type Complexes with Aliphatic Amine Ligands
Authors: Yamaguchi‐Terasaki Yukiko , Fujihara Takashi , Kaizaki Sumio 
Published: June 2007

AbstractWe have previously reported the relationship between 2H NMR chemical shift differences (Δδ) and the angular overlap model (AOM) parameter eσ(F), which represents the σ antibonding interaction energy obtained from the solvatochromism, for trans‐[CrF2([D4]‐3,2,3‐tet)]n+ {[D4]3,2,3‐tet = 1,10‐diamino‐4,7‐diazadecane [NH2(CH2)3NH(CD2)2NH(CH2)3NH2]} and cis‐α‐[CrF2([D4]trien)]n+ {[D4]trien = triethylenetetraamine [NH2(CH2)2NH(CD2)2NH(CH2)2NH2]}. In analogy to these relations, the co‐ligand effect on the Δδ values for cis‐α‐[CrX2([D4]trien)]n+ and trans‐[CrX2([D4]3,2,3‐tet)]n+ is found to be well correlated with the reported eσ(X) values for the co‐ligands X. This is the first example of the co‐ligand effect, or a mutual influence of ligands, associated with variation of the Cr–N and Cr–X bonds in cis‐ and trans‐[CrX2N4]‐type complexes. This Δδ vs. eσ(X) correlation offers an indirect method for estimating the eσ(X) values for didentate X2 as well as monodentate X ligands from the 2H NMR chemical shifts and ranking them in the two‐dimensional spectrochemical series. Plots of Δδ vs. eσ(FX) for trans‐[CrF(X)([D4]3,2,3‐tet)]n+ do not necessarily lie on the Δδ vs. eσ(X) correlation line for the F(X) complexes with averaged eσ(FX) = 1/2[eσ(X) + eσ(F)] values ― eσ[F(CN)] is close to eσ(F), for example ― thereby demonstrating a mutual influence between the CN– and F– ligands in the trans positions through a push‐pull action or π donor–acceptor interaction.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
New Open‐Framework Mixed‐Valence Chromium(III) Cerium(III)/(IV) Sulfate: CrCeIII7CeIV6(HSO4)6(SO4)21·75H2O
Authors: Casari Barbara M. , Langer Vratislav 
Published: June 2007

AbstractThe title compound, synthesized from CrVI and CeIV species, crystallizes in the space group P63 with a = 19.3015(2), c = 25.2684(4) Å, and Z = 2. The structural design of the title compound differs essentially from structures of known mixed‐valence cerium compounds which all form three‐dimensional networks. In the title compound the cerium atoms, interlinked by sulfate groups, extend to form layers held together by hydrogen‐bonding contacts. Perpendicular to these layers there are 10 Å wide channels. One third of the channels host solvent water only, while the other two thirds of the channels also host [Cr(H2O)6]3+ and [Ce(SO4)3(H2O)6]3– units, blocking each of these channels once per unit cell, resulting in 14 Å long voids.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Controlled Stabilization and Flocculation of Gold Nanoparticles by Means of 2‐Pyrazin‐2‐ylethanethiol and Pentacyanidoferrate(II) Complexes
Authors: Toma Sergio H. , Bonacin Juliano A. , Araki Koiti , Toma Henrique E. 
Published: June 2007

Abstract2‐Pyrazin‐2‐ylethanethiol (PZT) interacts with gold nanoparticles (AuNps) and pentacyanidoferrates, providing a suitable bridging ligand for the exploitation of the coordination chemistry involved in the stabilization of the colloidal solutions and in the controlled formation of aggregates in the presence of dimethyl sulfoxide. The electronic and vibrational spectra of the molecules have been investigated and discussed based on DFT and ZINDO/S theoretical calculations. The PZT‐modified AuNps exhibit strong SERS, coherent with the electromagnetic enhancement mechanism. In contrast, the charge‐transfer mechanism seems to predominate in the Raman spectra of the [Fe(CN)5PZT]3–‐modified gold nanoparticles.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Steric and Electronic Effects in the Dimerization of Wanzlick Carbenes: The Alkyl Effect
Authors: Denk Michael K. , Hezarkhani Azardokht , Zheng Feng‐Lan 
Published: June 2007

AbstractThe steric and electronic influence of N‐alkyl substituents on the dimerization energies ΔG° of Wanzlick carbenes (imidazolidin‐2‐ylidenes) was investigated experimentally and through DFT methods for a series of non‐symmetrically substituted Wanzlick carbenes. A series of 3‐alkyl‐1‐tert‐butylimidazolidin‐2‐ylidenes with decreasing steric demand of the alkyl substituent (isopropyl, ethyl and methyl) were obtained in four steps from the commercially available N‐alkylaminoethanol compounds. The carbenes are hydrolytically sensitive, colorless oils that can be distilled without decomposition and show no sign of dimerization to the respective enetetramines, even after prolonged heating. Calculations at the B98/6‐31G(d) level confirm that the dimerization of all three carbenes is thermodynamically unfavorable. To separate the steric and electronic stabilization of Wanzlick carbenes by N‐alkyl substituents, the formation energies of R,H3 mono‐alkyl enetetramines were used to derive electronic increments for the N‐alkyl substituents. The computational data show that all alkyl substituents electronically stabilize Wanzlick carbenes vs. their dimerization products with increments ranging from 2.97 kcal mol–1 (N‐methyl) to as high as 6.28 kcal mol–1 (N‐tert‐butyl). For combinations of N‐methyl, N‐ethyl and N‐isopropyl substituents, the increments are additive and the dimerization energies were found to be free of noticeably steric effects. Significant steric strain was found for all tBu‐substituted carbenes with strain energies of the dimerization products ranging from 6.92 kcal mol–1 [formation of (E)‐Me2tBu2‐enetetramine] to 24.23 kcal mol–1 (formation of tBu4 enetetramine). The tert‐butyl substituent thus assumes a unique position by strongly stabilizing the carbenes electronically as well as sterically.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Repeated Dihydrogen Elimination from Boranes and Gallanes Stabilized by Guanidine‐Type Bases: A Quantum Chemical Study Motivated by Recent Experimental Results
Authors: Ciobanu Oxana , Himmel Hans‐Jörg 
Published: June 2007

AbstractMonomeric boranes and gallanes stabilized by guanidine derivatives undergo in certain cases H2 elimination reactions leading in a first step to dinuclear E(III) hydrides (E = B or Ga) and in the second step upon elimination of further H2 to dinuclear compounds with the elements in the formal oxidation state +II featuring a direct E–E bond. The thermodynamics for such H2 elimination reactions were calculated applying several methods and basis sets. In addition the calculations provide information about possible mechanisms. Thus the calculations suggest the first step to be an intramolecular H2 elimination followed by a cycloaddition reaction. The second H2 elimination, in which E–E and H–H bonds are formed at the expense of E–H bonds, is almost energy neutral, as anticipated from the small differences in electronegativity between E and H. The reaction barriers are important indicators to answer the question if H2 elimination can be made reversible. Reversible H2 elimination and addition would make this class of compounds in principle interesting for hydrogen storage applications, although obviously the weight percentage of stored dihydrogen is in the special systems presented herein not sufficient for mobile applications. The compounds can also be applied for dehydrocoupling and transfer hydrogenation to deliver a stoichiometric amount of H2 to olefins. Finally, the possibility of elimination of a third H2 leading to a dinuclear E(I) species with an E–E double bond is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
An Acyclic Aminonaphthyridine‐Based Receptor for Carbohydrate Recognition: Binding Studies in Competitive Solvents
Authors: Mazik Monika , Cavga Hüseyin 
Published: June 2007

Abstract1H NMR spectroscopic and microcalorimetric titrations revealed that receptor 3b, consisting of three protonated 2‐amino‐1,8‐naphthyridine units, binds N‐acetylneuraminic acid (Neu5Ac), the most commonly occurring sialic acid, with high affinity in competitive solvents such as water/dimethyl sulfoxide. Receptor 3b is able to form neutral/charge‐reinforced hydrogen bonds and ion pairs with Neu5Ac, similar to sialic acid‐binding proteins. Furthermore, indications for weak binding of neutral sugars, such as methyl β‐D‐glucopyranoside, D‐maltose and D‐cellobiose were provided by NMR spectroscopy. Molecular modelling calculations, synthesis and binding studies in aqueous media are described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Performance evaluation of steel reduced flange plate moment connections
Authors: Chou Chung‐Che , Wu Chia‐Ching 
Published: June 2007

AbstractThis study details a new moment connection that overcomes difficulties in achieving field‐weld quality and eliminates steel beam buckling encountered in steel moment connections. This study presents cyclic test and finite element analysis results of full‐scale subassemblies using steel reduced flange plates (RFPs) to connect steel beam flanges and the column without any other direct connection. Since the RFP connection is designed as strong column‐strong beam‐weak RFPs, the RFP functions as a structural fuse that eliminates weld fractures and beam buckling. Test and analytical results show that (1) the connections transferred the entire beam flexural strength to the column and reached an interstorey drift of 4% with minor strength degradation, (2) failure of the connections was owing to buckling or fracturing of the RFP and not of the beam, and (3) the RFP connection subassembly, modelled using the nonlinear finite element computer program ABAQUS, exhibited hysteretic behaviour similar to that of the flange plate (FP) moment connection subassembly. The inelastic buckling force of the RFP was also evaluated by nonlinear regression analyses performed on a nonlinear model that relates buckling force to RFP geometries. Copyright © 2007 John Wiley & Sons, Ltd.
Discrete‐like crack simulation by smeared crack‐based FEM for reinforced concrete
Authors: Sato Yuichi , Naganuma Kazuhiro 
Published: June 2007

AbstractA numerical process that simulates crack propagation in reinforced concrete through post‐crack stress redistribution is presented. This process is developed within the context of the smeared crack approach. Continuity and orientation of the reinforcing bar components are automatically recognized in the pre‐processing stage. The process explicitly outputs crack widths by computing the bond slips along reinforcement, without imposing any additional nodes between the reinforcement and concrete. The process is incorporated with a finite element algorithm, and the validation is investigated through sample 3D static analyses of nine concrete specimens subjected to monotonic shear and flexure loads. These specimens contain relatively well‐distributed steel bars and fiber reinforced polymer (FRP) sheets of reinforcement ratio from 0.11 to 0.57%. The analyses predict the crack patterns and crack widths well, although some disagreements are found between the test and the analysis results. The proposed process outputs discrete, continuous in crack directions, and element boundary‐free crack patterns. Copyright © 2007 John Wiley & Sons, Ltd.
IntServ6: an approach to support QoS over IPv6 wired and wireless networks
Authors: Padilla Jhon J. , Paradells Josep 
Published: June 2007

AbstractIn this paper we propose a new approach for Quality of Service (QoS) support on Internet. This approach, named IntServ6, is based on the Integrated Services Architecture (ISA). It takes advantage of the IPv6 header flow label field to improve a set of the standard ISA properties such as reservations within tunnels, flows aggregation and interconnection with MPLS transport networks. IntServ6 can be used for QoS support in IPv6 wired and wireless networks. This paper describes the IntServ6 operation and performance evaluation over both environments. Evaluation results show that this approach has a better router performance with respect to the standard IntServ. Thus, IntServ6 reduces the mean packet delay and reduces the packet delay dependence with the mobility. Copyright © 2007 John Wiley & Sons, Ltd.
Dynamic stall modelling on airfoils based on strong viscous–inviscid interaction coupling
Authors: Riziotis Vasilis A. , Voutsinas Spyros G. 
Published: June 2007

AbstractThe prediction of the aerodynamic performance of pitching airfoils in stall conditions is considered in the context of strong viscous–inviscid interaction modelling. The aim of the work is to demonstrate the capabilities of a low‐cost dynamic stall model well suited for engineering applications. The model is formulated on the basis of a standard panel method combined with a vortex blob approximation of the wake. The development of the boundary layer over the airfoil and the evolution of the shear layer in the wake are taken into account by means of strong viscous–inviscid interaction coupling. To this end a transpiration layer is added to the inviscid formulation which represents the displacement effect viscosity results in the flow while the non‐linear coupled equations are solved simultaneously. Separation is modelled by introducing a second wake originating from the separation point (‘double‐wake’ concept) which is provided as part of the
boundary layer solution. The theoretical presentation of the model is supported with favourable comparisons to four sets of wind tunnel measurements. Copyright © 2007 John Wiley & Sons, Ltd.
Sediment provenance of late Quaternary morainic, fluvial and loess‐like deposits in the southwestern Verkhoyansk Mountains (eastern Siberia) and implications for regional palaeoenvironmental reconstructions
Authors: Popp Steffen , Belolyubsky Innokenty , Lehmkuhl Frank , Prokopiev Andrei , Siegert Christine , Spektor Valentin , Stauch Georg , Diekmann Bernhard 
Published: June 2007

AbstractA provenance analysis of late Quaternary deposits from tributaries of the Aldan and Lena rivers in Central Yakutia (eastern Siberia) was carried out using analysis of heavy minerals and clay mineralogy. Cluster analysis revealed one assemblage that is characterized by relatively high proportions of amphibole, orthopyroxene and garnet as well as pedogenic clay minerals, reflecting a sediment provenance from the wide catchment area of the Lena and Aldan rivers. In contrast, the three other clusters are dominated by stable heavy minerals with varying amounts of clinopyroxene, apatite and garnet, as well as high percentages of illite and chlorite that are indicative of source rocks of the Verkhoyansk Mountains. Glacial moraines reveal the local mountain source signal that is overprinted by the Lena‐Aldan signal in the oldest moraines by reworking processes. Alluvial sediments in the Verkhoyansk Foreland show a clear Lena source signal through intervals of the middle and late Pleistocene, related to a stream course closer to the mountains at that time. Loess‐like cover sediments are characterized by the dominant Lena provenance with increasing proportions of local mountain sources towards the mountain valleys. Aeolian sands in an alluvial terrace section at the mountain margin covering the time between 30 ka and 10 ka BP reflect temporarily dominant inputs of aeolian materials from the Lena Plains. Copyright © 2007 John Wiley & Sons, Ltd.
Does free complementary health insurance help the poor to access health care? Evidence from France
Authors: Grignon Michel , Perronnin Marc , Lavis John N. 
Published: June 2007

AbstractThe French government introduced a ‘free complementary health insurance plan’ in 2000, which covers most of the out‐of‐pocket payments faced by the poorest 10% of French residents. This plan was designed to help the non‐elderly poor to access health care. To assess the impact of the introduction of the plan on its beneficiaries, we use a longitudinal data set to compare, for the same individual, the evolution of his/her expenditures before‐and‐after enrolment in the plan. This before‐and‐after analysis allows us to remove most of the spuriousness due to individual heterogeneity. We also use information on past coverage in a difference‐in‐difference analysis to evaluate the impact of specific benefits associated with the plan. We attempt at controlling for changes other than enrolment through a difference‐in‐difference analysis within the eligible (rather than enrolled) population. Our main result is the plan's lack of an overall effect on utilization. This result is likely attributable to the fact that those who were enrolled automatically in the free plan (the majority of enrollees), already benefited from a relatively generous plan. The significant effect among those who enrolled voluntarily in the free plan was likely driven by those with no previous complementary coverage. Copyright © 2007 John Wiley & Sons, Ltd.
Predictors of response of U.S. veterans to treatment for the hepatitis C virus
Authors: Backus Lisa I. , Boothroyd Derek B. , Phillips Barbara R. , Mole Larry A. 
Published: June 2007

Abstract

The currently recommended treatment for hepatitis C virus (HCV) infection is pegylated interferon alfa (PEG-INF) and ribavirin, which can be difficult to tolerate. More information about predicting sustained virologic response (SVR) may allow more informed treatment decisions to be made. This retrospective observational cohort study identified predictors of SVR to PEG-INF and ribavirin in routine medical practice at 121 Department of Veterans Affairs facilities. Among 5,944 patients infected with HCV genotypes 1, 2, or 3 who had been treated with PEG-INF and ribavirin, SVR rates were 20%, 52%, and 43%, respectively, and discontinuation rates were 68% (prior to 48 weeks), 34% (24 weeks), and 41% (24 weeks), respectively. In multivariate analysis, significant predictors of decreased likelihood of genotype 1 patients having an SVR were being African American, clinical liver disease, diabetes, low cholesterol, low hemoglobin, low platelet count, and treatment at a low-volume facility. Predictors of increased likelihood of genotype 1 patients having an SVR were low-level HCV viremia, elevated ALT quotient, and receiving PEG-INF 2A (rather than 2B). For genotype 2 patients, increasing body mass index, prior use of interferon, and low platelet count were negative predictors; only low-level HCV viremia was a positive predictor. For genotype 3 patients, only receiving PEG-INF 2A affected the likelihood of an SVR; its effect was positive.

Conclusion:

Among patients for whom HCV treatment is initiated during routine medical care, multiple factors including form of PEG-INF received affect the SVR rate for genotype 1 patients. Few of these factors affect the rate for genotype 2 patients, and even fewer do so for genotype 3 patients. (HEPATOLOGY 2007.)
Assembly and budding of a hepatitis B virus is mediated by a novel type of intracellular vesicles
Authors: Mhamdi Mouna , Funk Anneke , Hohenberg Heinz , Will Hans , Sirma Hüseyin 
Published: June 2007

Abstract

Formation of enveloped viruses involves assembly and budding at cellular membranes. In this study, we elucidated the morphogenesis of hepadnaviruses on the ultrastructural and biochemical level using duck hepatitis B virus (DHBV) as a model system. Formation of virus progeny initiates at the endoplasmic reticulum (ER) and is conserved both in vitro and in vivo. The morphogenesis proceeds via membrane-surrounded vesicles containing both virions and subviral particles, indicating a common morphogenetic pathway. The virus particle–containing vesicles (VCVs) are generated and maintained by reorganization of endomembranes accompanied by a striking disorganization of the rough ER (rER). VCVs are novel organelles with unique identity and properties of ER, intermediate compartment, endosomes, and multivesicular bodies. VCVs are dynamic structures whose size and shape are regulated by both membrane fusion and fission.

Conclusion:

Our data indicate a strong reorganization of endomembranes during DHBV infection, resulting in the biogenesis of novel organelles serving as multifunctional platforms for assembly and budding of virus progeny. (HEPATOLOGY 2007.)