bluuebunny/crossref_metadata_2025_split huggingface dataset:
D-Dimer Concentrations in Normal Pregnancy: New Diagnostic Thresholds Are Needed
Authors: Kline Jeffrey A , Williams Ginger W , Hernandez-Nino Jackeline 
Published: March 2005

Abstract
Background: Pregnancy is known to increase the D-dimer concentration above the conventional normal threshold of 0.50 mg/L, leading to an increased false-positive D-dimer test when venous thromboembolism (VTE) is clinically suspected in a pregnant patient. Our aim was to determine the effect of normal pregnancy on the D-dimer concentration.
Methods: Healthy women who were seeking to become pregnant and had no preexisting condition known to increase the D-dimer concentration were identified. Quantitative D-dimer measurements (MDA turbidimetric assay) and fibrinogen assays were performed before conception, at each trimester, and at 4 weeks postpartum. Patients were excluded for fetal loss or preeclampsia.
Results: A total of 50 women were enrolled in the study, and blood samples were obtained at preconception and all trimesters from 23 women. The mean (SD) preconception D-dimer concentration was 0.43 (0.49) mg/L, and 79% of women had a D-dimer concentration &lt;0.50 mg/L. D-Dimer increased with each trimester such that only 22% of women in the second trimester and none (of 23) in the third trimester (95% confidence interval, 0–14%) had a D-dimer concentration &lt;0.50 mg/L. We found no correlation between either the D-dimer and fibrinogen concentrations or between the increases in D-dimer and fibrinogen with pregnancy.
Conclusions: Normal pregnancy causes a progressive increase in circulating D-dimer. The D-dimer test has no use in ruling out VTE in the third trimester if a cutoff of 0.50 mg/L is used. A large management study is needed to establish new thresholds for the D-dimer to rule out VTE in each trimester.
Cover Picture: Bistable Nematic Liquid Crystals with Self‐Assembled Fibers (Adv. Mater. 6/2005)
Authors: Mizoshita N. , Suzuki Y. , Hanabusa K. , Kato T. 
Published: March 2005

AbstractThe cover shows a recording process using nematic liquid crystal alignment. On p. 692, Kato and co‐workers report that reversibly bistable states have been achieved for nematic liquid crystals incorporating a small amount of self‐assembled fibers. Homeotropic monodomains and non‐aligned multidomains can be fixed and switched by thermal treatment in electric fields. The technique is applied to the formation of rewritable light scattering patterns, as shown on the cover.
Weight‐height relationships and body mass index: Some observations from the diverse populations collaboration
Authors:   Diverse Populations Collaborative Group
Published: March 2005

AbstractBody mass index (BMI, weight (kg)/height (m)2) is the most widely used weight‐height index worldwide. This universal use of BMI assumes that the rationale for its use is universally applicable. We examine two possible rationales for using BMI as a universal measure. The first rationale is that BMI is strongly correlated with weight, but is independent of height. The second rationale is that BMI correctly captures the relationship between weight and height, which implies that the slope of log weight regressed on log height is 2. We examined the weight‐height relationship in 25 diverse population samples of men and women from the US, Europe, and Asia. The analysis included 72 subgroups with a total of 385,232 adults aged 25 years and older. Although BMI was highly correlated with weight in all studies, a significant, negative correlation between BMI and height was found in 31 out of 40 subgroups of men (r = −0.004 to −0.133) and 32 of 32 groups of women (r = −0.016 to −0.205). When log weight was regressed on log height, the 95% confidence intervals (CI) of the slopes did not include 2 in 25 out of 40 male subgroups. The summary estimate of the slopes across studies of men was 1.92 (95% CI, 1.87–1.97). For women, slopes were lower than 2 in 28 of 32 subgroups with a summary estimate of 1.45 (95% CI, 1.39–1.51). In most of the populations, BMI is not independent of height; weight does not universally vary with the square of height; and the relationship between weight and height differs significantly between males and females. The use of a single BMI standard for both men and women cannot be justified on the basis of weight‐height relationships. Am J Phys Anthropol 128:220‐229, 2005. © 2005 Wiley‐Liss, Inc.
Measurement and modeling of poly(vinyl acetate)–solvent viscosity mixtures
Authors: Modarress Hamid , Mohsen‐Nia Mohsen 
Published: March 2005

AbstractThe viscosities of various poly(vinyl acetate) (PVAc)–solvent mixtures (PVAc–toluene, PVAc–benzene, and PVAc–cyclohexanone) were measured at different temperatures with a Haake viscometer. The required molecular weight of a commercial‐grade PVAc sample was measured with an Ubbelohde viscometer. The measured viscosities were correlated with a previously proposed viscosity model, and the model parameters were calculated. The results indicated the applicability of the model to the viscosity calculations of PVAc–solvent mixtures. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1244–1249, 2005
Mechanism of Anionic Dearomatizing Reactions of Diphenylphosphinamide Derivatives: A Theoretical and Experimental Study
Authors: Ramallal Antonio Morán , Fernández Ignacio , López Ortiz Fernando , González Javier 
Published: March 2005

AbstractThe mechanism of the anionic dearomatisation of phosphinamide derivatives has been investigated both theoretically and experimentally. The potential‐energy surface of model reactions was studied at the Becke3LYP/6‐31+G* level of theory, and according to this study, a pre‐reactive complex is formed between the alkyllithium and the phosphinamide. This complex evolves preferentially through NCα‐metalation of the phosphinamide. The intramolecular nucleophilic addition of the carbanion to the ortho position of the aromatic ring leads to the dearomatised products, in a reaction that has been shown to be under thermodynamic control. Coordinating co‐solvents, such as hexamethyl phosphoramide (HMPA) or N,N′‐dimethyl‐N,N′‐propylene urea (DMPU), appear to influence the reaction by favouring the formation of solvent‐separated ion pairs. The cyclisation reaction of allylphosphinamide derivatives was also studied. It was found that both the α‐ and γ‐attack of the allyl anion can take place, however the formation of the seven‐membered ring products derived from the γ‐attack are clearly favoured.
Photoinduced Electron Transfer Reactions by SmI2 in THF: Luminescence Quenching Studies and Mechanistic Investigations
Authors: Prasad Edamana , Knettle Brian W. , Flowers Robert A. 
Published: March 2005

AbstractPhotoluminescence quenching studies of SmI2 in dry THF were carried out in the presence of five different classes of compounds: ketone, alkyl chloride, nitrile, alkene and imine. The free energy change (ΔG 0) of the photoinduced electron transfer (PET) reactions was calculated from the redox potentials of the donor (SmI2) and acceptors. The bimolecular quenching constants (kq) derived from the Stern–Volmer experiments parallel the free energy changes of the PET processes. The observed quenching constants were compared with the theoretically derived electron transfer rate constants (ket) from Marcus theory and found to be in good agreement when a value of λ=167 kJ mol−1 (40 kcal mol−1) was used for the reorganization energy of the system. A careful comparison of the excited state dynamics of SmII in the solid state to the results obtained in solution (THF) provides new insight in to the excited states of SmII in THF. The activation parameters determined for the PET reactions in SmI2/1‐chlorobutane system are consistent with a less ordered transition state and high degree of bond reorganization in the activated complex compared to similar ground state reactions. Irradiation studies clearly show that SmI2 acts as a better reductant in the excited state and provides an alternative pathway for rate enhancement in known and novel functional group reductions.
Synthesis, X‐ray Crystal Structures, and Gas Sorption Properties of Pillared Square Grid Nets Based on Paddle‐Wheel Motifs: Implications for Hydrogen Storage in Porous Materials
Authors: Chun Hyungphil , Dybtsev Danil N. , Kim Hyunuk , Kim Kimoon 
Published: March 2005

AbstractA systematic modulation of organic ligands connecting dinuclear paddle‐wheel motifs leads to a series of isomorphous metal‐organic porous materials that have a three‐dimensional connectivity and interconnected pores. Aromatic dicarboxylates such as 1,4‐benzenedicarboxylate (1,4‐bdc), tetramethylterephthalate (tmbdc), 1,4‐naphthalenedicarboxylate (1,4‐ndc), tetrafluoroterephthalate (tfbdc), or 2,6‐naphthalenedicarboxylate (2,6‐ndc) are linear linkers that form two‐dimensional layers, and diamine ligands, 4‐diazabicyclo[2.2.2]octane (dabco) or 4,4′‐dipyridyl (bpy), coordinate at both sides of Zn2 paddle‐wheel units to bridge the layers vertically. The resulting open frameworks [Zn2(1,4‐bdc)2(dabco)] (1), [Zn2(1,4‐bdc)(tmbdc)(dabco)] (2), [Zn2(tmbdc)2(dabco)] (3), [Zn2(1,4‐ndc)2(dabco)] (4), [Zn2(tfbdc)2(dabco)] (5), and [Zn2(tmbdc)2(bpy)] (8) possess varying size of pores and free apertures originating from the side groups of the 1,4‐bdc derivatives. [Zn2(1,4‐bdc)2(bpy)] (6) and [Zn2(2,6‐ndc)2(bpy)] (7) have two‐ and threefold interpenetrating structures, respectively. The non‐interpenetrating frameworks (1–5 and 8) possess surface areas in the range of 1450–2090 m2g−1 and hydrogen sorption capacities of 1.7–2.1 wt % at 78 K and 1 atm. A detailed analysis of the sorption data in conjunction with structural similarities and differences concludes that porous materials with straight channels and large openings do not perform better than those with wavy channels and small openings in terms of hydrogen storage through physisorption.
Structure Characterization and Possible Biogenesis of Three New Families of Nortriterpenoids: Schisanartane, Schiartane, and 18‐Norschiartane
Authors: Li Rong‐Tao , Xiao Wei‐Lie , Shen Yun‐Heng , Zhao Qin‐Shi , Sun Han‐Dong 
Published: March 2005

AbstractFour new, highly oxygenated nortriterpenoids with unique schisanartane skeletons, micrandilactones D–G (1–4), have been isolated from the leaves and stems of Schisandra micrantha, and their structures have been elucidated on the basis of extensive spectral studies. The postulated biogenetic sequences of sixteen highly oxygenated nortriterpenoids and bisnortriterpenoids with new skeletons from three Schisandra species are discussed and have been compared from a chemotaxonomic standpoint.
Native myelin oligodendrocyte glycoprotein promotes severe chronic neurological disease and demyelination in Biozzi ABH mice
Authors: Smith Paul A. , Heijmans Nicole , Ouwerling Boudewijn , Breij Esther C. , Evans Nicholas , van Noort Johannes M. , Plomp Arianne C. , Delarasse Cécile , ‘t Hart Bert , Pham‐Dinh Danielle , Amor Sandra 
Published: March 2005

AbstractMyelin oligodendrocyte glycoprotein (MOG) is a powerful encephalitogen for experimental autoimmune demyelination. However, the use of MOG peptides or recombinant proteins representing part of the protein fails to fully address the possible pathogenic role of the full‐length myelin‐derived protein expressing post‐translational modifications. Immunization of mice with central nervous system tissues from wild‐type (WT) and MOG‐deficient (MOG–/–) mice demonstrates that MOG in myelin is necessary for the development of chronic demyelinating experimental autoimmune encephalomyelitis (EAE) in mice. While immunization with WT spinal cord homogenate (SCH) resulted in a progressive EAE phenotype, MOG–/– SCH induced a mild self‐limiting acute disease. Following acute EAE with MOG–/– SCH, mice developed T cell responses to recombinant mouse MOG (rmMOG), indicating that MOG released from myelin is antigenic; however, the lack of chronic disease indicates that such responses were not pathogenic. Chronic demyelinating EAE was observed when MOG–/– SCH was reconstituted with a dose of rmMOG comparable to MOG in myelin (2.5% of total white matter‐derived protein). These data reveal that while immunization with the full‐length post‐translational modified form of MOG in myelin promotes the development of a more chronic autoimmune demyelinating neurological disease, MOG (and/or other myelin proteins) released from myelin during ongoing disease do not induce destructive autoimmunity.
Experimental investigation on the role of water in the mechanical behavior of structural dentine
Authors: Kishen A. , Asundi A. 
Published: March 2005

AbstractDentine is a porous hydrated composite structure that forms the major bulk of the human tooth. The aim of this study was to investigate the role of free water on the in‐plane, mechanical strain response in dentine structure. A digital moiré interferometry was used for this purpose. It was observed from this experiment that structural dentine demonstrated distinct strain gradients in the axial (perpendicular to the dentinal tubules) and lateral (parallel to the dentinal tubules) directions. The hydrated dentine displayed significant increase in strain with stress in the direction perpendicular to the dentinal tubules, and this response was characteristic of a tough material. On the contrary, the dehydrated dentine, which was dehydrated at 24°C, 55% relative humidity for 72 h showed a strain response characteristic of a brittle material. The strains formed in the direction parallel to the dentinal tubules for hydrated dentine were consistent and did not vary much with increase in applied loads. Upon dehydration, the outer dentine experienced higher strains, and the difference between the outer and inner dentine became more conspicuous with increase in loads. This experiment highlights hydration‐induced, distinct in‐plane strain gradients in the directions perpendicular and parallel to the dentinal tubules in the dentine structure. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 192–200, 2005
Levels of 4‐aminobiphenyl‐induced somatic H‐ras mutation in mouse liver DNA correlate with potential for liver tumor development
Authors: Parsons Barbara L. , Beland Frederick A. , Von Tungeln Linda S. , Delongchamp Robert R. , Fu Peter P. , Heflich Robert H. 
Published: March 2005

AbstractThe utility of liver H‐ras codon 61 CAA to AAA mutant fraction as a biomarker of liver tumor development was investigated using neonatal male mice treated with 4‐aminobiphenyl (4‐ABP). Treatment with 0.1, 0.3, or 1.0 μmol 4‐ABP produced dose‐dependent increases in liver DNA adducts in B6C3F1 and C57BL/6N mice. Eight months after treatment with 0.3 μmol 4‐ABP or the DMSO vehicle, H‐ras codon 61 CAA to AAA mutant fraction was measured in liver DNA samples (n = 12) by allele‐specific competitive blocker‐polymerase chain reaction (ACB‐PCR). A significant increase in average mutant fraction was found in DNA of 4‐ABP‐treated mice, with an increase from 1.3 × 10−5 (control) to 44.9 × 10−5 (treated) in B6C3F1 mice and from 1.4 × 10−5 to 7.0 × 10−5 in C57BL/6N mice. Compared with C57BL/6N mutant fractions, B6C3F1 mutant fractions were more variable and included some particularly high mutant fractions, consistent with the more rapid development of liver foci expected in B6C3F1 mouse liver. Twelve months after treatment, liver tumors developed in 79.2% of 4‐ABP‐treated and 22.2% of control B6C3F1 mice; thus measurement of H‐ras mutant fraction correlated with subsequent tumor development. This study demonstrates that ACB‐PCR can directly measure background levels of somatic oncogene mutation and detect a carcinogen‐induced increase in such mutation. Published 2005 Wiley‐Liss, Inc.
Analysis of three‐dimensional crack initiation and propagation using the extended finite element method
Authors: Areias Pedro M. A. , Belytschko Ted 
Published: March 2005

AbstractAn Erratum has been published for this article in International Journal for Numerical Methods in Engineering 2005, 63(8): 1228.We present a new formulation and a numerical procedure for the quasi‐static analysis of three‐dimensional crack propagation in brittle and quasi‐brittle solids. The extended finite element method (XFEM) is combined with linear tetrahedral elements. A viscosity‐regularized continuum damage constitutive model is used and coupled with the XFEM formulation resulting in a regularized ‘crack‐band’ version of XFEM. The evolving discontinuity surface is discretized through a C0 surface formed by the union of the triangles and quadrilaterals that separate each cracked element in two. The element's properties allow a closed form integration and a particularly efficient implementation allowing large‐scale 3D problems to be studied. Several examples of crack propagation are shown, illustrating the good results that can be achieved. Copyright © 2005 John Wiley & Sons, Ltd.
Kinetic study of TNF‐α production and its regulatory mechanisms in acinar cells during acute pancreatitis induced by bile–pancreatic duct obstruction
Authors: Ramudo Laura , Manso Manuel A , Sevillano Sara , de Dios Isabel 
Published: March 2005

AbstractCytokines play a critical role in acute pancreatitis (AP) but the contribution of different cell sources to cytokine production is unclear. Unfortunately, there are no data concerning the molecular mechanisms involved in the inflammatory response in humans during AP. For this reason, the aim of this study was to analyse the ability of acinar cells, in comparison with leukocytes, to produce TNF‐α at different stages of AP induced in rats by bile–pancreatic duct obstruction (BPDO) and to investigate the time course of oxidant‐sensitive mechanisms involved in cytokine production. The role of oxygen free radicals as messengers of the mechanisms underlying acinar cell TNF‐α production was assessed in BPDO rats treated with N‐acetylcysteine (NAC). While monocytes were not able to produce TNF‐α until 12 h after inducing AP, acinar cells triggered TNF‐α production from 6 h after BPDO, at which time the pancreas develops maximal oxidative stress. Phosphorylated p38‐MAPK and activated NF‐κB were detected in acinar cells from 6 h after BPDO. NAC treatment reduced pancreatic glutathione depletion during the early stages of AP and attenuated the activation of p38‐MAPK and NF‐κB for 48 h following BPDO. As a result, acinar cells in NAC‐treated rats failed to produce TNF‐α during AP. In addition, NAC delayed monocyte TNF‐α production, thereby maintaining low TNF‐α levels in plasma during BPDO. In conclusion, acinar cells contribute directly to the inflammatory response during BPDO‐induced AP by producing TNF‐α even before inflammatory cells in the peripheral blood. The blockade of oxidant‐mediated signal transduction pathways induced by NAC treatment prevented acinar cell TNF‐α production. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
A new Fourier transform photo‐modulation spectroscopic technique for narrow band‐gap materials in the mid‐ to far‐infra‐red
Authors: Hosea T. J. C. , Merrick M. , Murdin B. N. 
Published: March 2005

AbstractThere is a large number of technologically important semiconducting optoelectronic materials with narrow band‐gaps in the “finger‐print” region of the infra‐red (IR) spectrum. However, in many instances their band‐structures have not been very well characterised, making it difficult to engineer their properties. Part of the reason is that the key non‐destructive optical characterisation tool, modulation spectroscopy, becomes increasingly difficult as one attempts to look further out into the IR. To date, conventional diffraction‐grating‐based modulation spectroscopy has been applied predominantly below ∼4 µm. We have developed a new photo‐modulation system, based on a Fourier transform spectrometer, that permits such measurements out to much longer wavelengths. We discuss the advantages and technical difficulties of implementing such a system, and give the results obtained so far for narrower‐gap materials, including bulk‐like GaSb, InAs and InSb, comparing these with what can be obtained with conventional modulation spectroscopy arrangements. We apply our new technique to measure the bandgap in dilute‐N InSbN, achieving what we believe are the first modulation spectroscopy measurements in the mid‐IR beyond ∼6 µm. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positron annihilation study of HVPE grown thick GaN layers
Authors: Misheva M. , Larsson H. , Gogova D. , Monemar B. 
Published: March 2005

AbstractSingle‐crystalline GaN layers with a thickness up to 330 µm were grown by hydride vapor phase epitaxy on basal plane sapphire at gallium stable conditions in a bottom‐fed vertical reactor at atmospheric pressure. Positron annihilation spectroscopy experiments were implemented in order to identify native point defects in the as‐grown non‐intentionally doped n‐type GaN. Comparatively low concentrations of Ga vacancy related defects in the order of 1016 to 1017 cm–3 were extracted from the positron annihilation spectroscopy data. The Ga vacancy defect concentration was related to the intensity of the yellow photoluminescence band centered at 2.2 eV. The influence of the growth rate on the Ga vacancy related defect concentration was investigated. A trend of decreasing of the defect concentration with increasing of layer thickness is observed, which correlates with improving crystalline quality with the thickness. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic properties of a transverse Ising model with a four‐spin interaction
Authors: Kaneyoshi T. 
Published: March 2005

AbstractThe magnetic properties (phase diagram and magnetizations) of the spin‐½ transverse Ising model with two‐spin (J) and four‐spin (J4) interactions on honeycomb lattice are investigated by the use of the correlated effective‐field theory superior to the standard mean‐field and the Zernike approximations. The results of the phase diagram are greatly different from those obtained within the Zernike approximation, especially for the negative region of the ratio α (α = J4/J). In the low‐temperature region, the longitudinal and transverse magnetizations show many characteristic behaviors in the variation of α. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A model for the microwave assisted magnetoresistance oscillations in a 2D electron system
Authors: Torres Manuel , Kunold Alejandro 
Published: March 2005

AbstractIn this work we present a model for the photoconductivity of a two dimensional electron system (2DES) subjected to a magnetic field. The model includes the microwave and Landau contributions in a non‐perturbative exact way, Impurity scattering effects are treated perturbatively. Based on this formalism, we provide a Kubo‐like formula that takes into account the oscillatory Floquet structure of the problem. We discuss results related with the recently discovered zero‐resistance states. It is found that, in agreement with experiment, negative dissipation can only be induced in very high mobility samples. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)