bluuebunny/crossref_metadata_2025_split huggingface dataset:
Association of cytomegalovirus infection with post‐transplantation cardiac rejection as studied using the polymerase chain reaction
Authors: Fernando Sirimali , Booth James , Boriskin Yuri , Butcher Philip , Carrington David , Steel Helen , Tryhorn Yvonne , Corbishley Catherine , Keeling Philip , Murday Andrew , McKenna William 
Published: March 2007

AbstractThe relationship between cytomegalovirus (CMV) infection and cardiac allograft rejection is controversial, some authors reporting a significant association, others not, on the basis of the results of conventional virological diagnosis by culture or serology. This problem was reinvesti‐gated in 88 patients using a semi‐quantitative nest polymerase chain reaction (PCR) procedure for detecting CMV DNA in endomyocardial biopsy specimens. Significantly more positive biopsies were obtained from patients with moderate (grade 2; P = 0.02) or severe (grade 3a‐4; P = 0.03) rejection than with no or mild (grade 0‐1 b) rejection, whereas there was no significant association between rejection and CMV as diagnosed by virus isolation from urine, throat or blood, or by the detection of CMV‐IgM.PCR‐positive biopsies originated most frequently from CMV‐antibody positive recipients (R+) of hearts from seropositive donors (D+), in association with moderate or severe rejection rather than with mild or no rejection The detection of CMV in the heart thus seemed to be related more to R+D+ serological status than to severity of rejection, that is, to circumstances that favoured co‐infection with strains of CMV from both donor and recipient. Studies on sequential biopsy specimens from selected patients also provided evidence that CMV infection and rejection were not always related events.The PCR was able to differentiate latent from active CMV infection; moreover, some seroneg‐ative individuals gave repeatedly positive biopsies, thereby supporting the work of others that some patients undergo CMV infection without mounting a detectable antibody response.The use of the PCR provided additional and more definitive information linking CMV and post‐transplantation cardiac rejection when compared to conventional methods of viral diagnosis which were less suitable as correlates of deep seated focal infection. © 1994 Wiley‐Liss, inc.
Epidemiology of hepatitis C virus in Western Venezuela: Lack of specific antibody in indian communities
Authors: Blitz‐Dorfman Linda , Monsalve Francisca , Porto Leticia , Weir Jesús , Arteaga Melvis , Padrón Guillermo , León Pilar , Echevarría José M. 
Published: March 2007

AbstractHepatitis C virus (HCV) is transmitted mainly by the parenteral route after percutaneous exposure to virus‐infected products or body fluids. Thus, HCV shares with hepatitis B and D (HBV, HDV) viruses this common transmission route. The prevalence of antibody against HCV (anti‐HCV) was studied in 1155 serum samples from individuals at risk of infection by bloodborne or sexually transmitted agents, as well as from others lacking such risk factors, from the city of Maracaibo, Venezuela. Anti‐HCV and serological markers of infection by HBV and HDV were also studied in further 550 samples taken from Bari Indians living in different communities in the Perija mountains. State of Zulia, Venezuela. The results obtained showed that recipients of blood or blood products are at increased risk of HCV infection in Maracaibo, whereas sexual transmission plays only a minor role if any. Both HBV and HDV infections were highly prevalent among Bari Indians (64.4% positive for anti‐HBc; 11.1% of HBsAg carriers; 15.3% positive for anti‐HDV among HBsAg carriers). No anti‐HCV positive samples were, however, detected among them, thus suggesting either that HCV has not still reached this population or that HBV and HDV are transmitted by routes unshared by HCV. Anti‐HCV was also absent among samples from mentally retarded patients from Maracaibo, thus confirming similar findings from other countries and supporting the existence of specific transmission mechanisms for HBV and HDV which are not working for HCV. © 1994 Wiley‐Liss, Inc.
Characterization of substituted polyacetylene microstructure by pyrolysis gas chromatography
Authors: Doležal Zdeněk , Kubinec Róbert , Sedláček Jan , Pacáková Vera , Vohlídal Jirí 
Published: March 2007

AbstractA series of substituted acetylenes has been polymerized with WOCl4/Ph4Sn metathesis catalyst and [Rh(cod)OMe]2 insertion catalyst, and the thermal degradation of the polyacetylenes prepared has been studied using pyrolysis capillary gas chromatography (Py‐GC) with flame ionization and mass spectrometric detection to obtain information on the effect of the catalyst on the head‐tail (H‐T) isomerism of polyacetylenes (poly(phenylacetylene), poly[(4‐methylphenyl)acetylene], poly(benzylacetylene), poly[(2‐fluorophenyl)acetylene], poly[(3‐fluorophenyl)acetylene], and poly[(4‐fluorophenyl)acetylene]). Cyclotrimers have been found to be the main pyrolysis products in all cases. Direct Py‐MS connection was used to determine the temperature profiles of the released pyrolysis products. 1,3,5‐Trisubstituted benzenes were found to be the predominant pyrolysis products of the polymers prepared with the insertion catalyst, which proves the presence of long head‐to‐tail sequences of monomeric units in these polyacetylenes. On the other hand, both 1,2,4‐ and 1,3,5‐trisubstituted benzenes are present in significant amounts in the pyrolysis products of polymers prepared with the metathesis catalyst, which proves the presence of a significant content of the head‐to‐head (HH) and tail‐to‐tail (TT) linkages in these isomers of polyacetylenes. Contents of the regular (HT) and inverse (HH‐TT) monomer linkages (RML and IML, respectively) in polymer chains were determined from the relative amounts of di‐, tri‐, and tetrasubstituted benzenes found in the Py‐GC products.
On RD‐rational Krylov approximations to the core‐functions of exponential integrators
Authors: Moret I. 
Published: March 2007

AbstractThe paper deals with the application of the restricted‐denominator rational Krylov method, recently discussed in (BIT 2004; 44(3):595–615; SIAM J. Sci. Comput. 2005; 27:1438–1457), to the computation of the action of the so‐called φ‐functions, which play a fundamental role in several modern exponential integrators. The analysis here presented is devoted in particular to the construction of error estimates of easy practical use. Copyright © 2007 John Wiley & Sons, Ltd.
H(curl) auxiliary mesh preconditioning
Authors: Kolev Tzanio V. , Pasciak Joseph E. , Vassilevski Panayot S. 
Published: March 2007

AbstractThis paper analyses a two‐level preconditioning scheme for H(curl) bilinear forms. The scheme utilizes an auxiliary problem on a related mesh that is more amenable for constructing optimal order multigrid methods. More specifically, we analyse the case when the auxiliary mesh only approximately covers the original domain. The latter assumption is important since it allows for easy construction of nested multilevel spaces on regular auxiliary meshes. Numerical experiments in both two and three space dimensions illustrate the optimal performance of the method. Published in 2007 by John Wiley & Sons, Ltd.
Boundary‐conforming coordinates with grid line control for acoustic scattering from complexly shaped obstacles
Authors: Villamizar Vianey , Weber Matthew 
Published: March 2007

AbstractThe current work sets forth a practical approach to numerically solve two‐dimensional direct acoustic scattering problems from complexly shaped scatterers with severe singularities, such as corners and cusps. First, boundary conforming coordinates are generated. This generation is performed through an elliptic grid generator algorithm, including control of the coordinate lines. The grid line control solely depends on the initial distribution of grid points. Following the grid generation process, the initial boundary value problem, modelling the scattering phenomenon, is formulated in terms of the new curvilinear coordinates, and a finite‐difference time domain method is implemented. The presence of the boundary singularities causes instability of the numerical method. However, by appropriately controlling the distance between grid lines in the vicinity of these singularities, stability and convergence are achieved. A semianalytical formula for the differential scattering cross‐section is obtained from the discrete Fourier transform of the computed scattered pressure field. The method is successfully applied to several interesting scatterers of various shapes. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007
Nasopharyngeal carcinoma: a review of its causes and its diagnosis in skeletal material
Authors: Mark S. 
Published: March 2007

AbstractSmoky fires in small, poorly ventilated structures have been cited as a risk factor for nasopharyngeal carcinoma (NPC) since the 1920s (Dobson, 1924). Furthermore, based on five cited cases of ancient NPC, it has been proposed that NPC was a common condition with a wide geographical distribution in ancient populations (Wells, 1964a,b). Both interpretations have continued to appear in the literature (Ortner, 2003), but recently, Aufderheide & Rodríguez‐Martín (1998) have argued that the number of cases of NPC is inflated due to ‘diagnostic imprecision’. This paper reviews medical advances that in the last few decades have shed considerable light on risk factors for NPC, and also reviews criteria for diagnosing NPC. Based on these data, a reexamination of the five cited cases of ancient NPC suggests that only one case may be NPC, and the prevalence and distribution of this disease may have been more variable than originally thought. Furthermore, a better understanding of the aetiology of NPC and criteria for diagnosis may allow for more precise research designs for studying ancient populations. Copyright © 2007 John Wiley & Sons, Ltd.
Kinetic study on copolymerization of ethylene and 1‐hexene catalyzed by Cp2ZrCl2/MAO catalytic system
Authors: Wang Jianfeng , Wang Li , Gao Haoqi , Wang Wenqin , Jiang Guohua , Dong Xiaocheng , Wang Wei , Feng Lianfang 
Published: March 2007

AbstractThe kinetics of ethylene and 1‐hexene copolymerization catalyzed by Cp2ZrCl2/MAO was studied. A new kinetic mathematical model that takes the reactivation effect of MAO into account has been developed. Applying this model, the good agreement between the experimental data and the fitting profiles was achieved. POLYM. ENG. SCI., 47:540–544, 2007. © 2007 Society of Plastics Engineers
Multiple criteria optimization with variability considerations in injection molding
Authors: Castro Carlos E. , Ríos Mauricio Cabrera , Castro José M. , Lilly Blaine 
Published: March 2007

AbstractInjection molding (IM) is the most important process for mass‐producing of plastic products. The difficulty of optimizing an IM process is that the performance measures (PMs) usually show conflicting behavior. The aim of this work is to demonstrate a method utilizing CAE, statistical testing, artificial neural networks (ANNs), and data envelopment analysis (DEA) to find the best compromises between multiple PMs, considering the variability in these PMs in an explicit manner. Two case studies are presented. The first case study, based on a virtual part, is discussed in detail in order to illustrate this method. The second case study is experimentally based and makes use of the American Society of Testing Materials (ASTM) mold to illustrate how this approach applies when purely experimental results are available. POLYM. ENG. SCI., 47:400–409, 2007. © 2007 Society of Plastics Engineers
Experimental characterization and computational simulations of the impact behavior of injection‐molded polymers
Authors: Viana Júlio C. , Cunha António M. , Billon Noelle 
Published: March 2007

AbstractThe multiaxial impact test in polymers is analyzed. The impact response of a propylene copolymer is characterized under different test conditions. Due to the nature of the impact event and to the complex material behavior, an intricate stress state is developed rendering rather difficult the assessment of the intrinsic impact properties. Furthermore, processing determine polymer microstructure, which significantly influences the impact response. The multiaxial impact test was simulated using a finite element code. The computed force‐displacement curves fall in between the computed ones with two extreme contact conditions between striker and plate. Friction plays an important role from medium strain levels until the peak force is reached, determining its intensity. The constitutive coefficients at high strain‐rates were identified by an inverse method. The adopted constitutive model allows the computation of the force‐deflection curve until the force peak, but not its full description. For that, a modified version was used that more correctly takes into account the strain hardening of the polymer. Finally, it is emphasized the importance of the knowledge of the heat conversion factor for realistically predicting the mechanical behavior of polymers at high strain‐rates. POLYM. ENG. SCI., 47:337–346, 2007. © 2007 Society of Plastics Engineers.
Intrinsic lifetime of polyethylene pipelines
Authors: Brown Norman 
Published: March 2007

AbstractAn equation was developed for calculating the time to failure by slow crack growth (SCG) failure in any polyethylene structure. The equation requires the following experimental inputs: (1) the resistance to SCG as measured by the PENT test (ASTM F1473), (2) the stress intensity of the defect from which failure originates, and (3) the temperature. A simple experiment for determining the stress intensity is presented. The equation was applied to SCG failures that are associated with the inherent random defects that occur in the wall of all pipes. The size of the inherent random defect that exists in commercial gas pipes was found to be 0.14 mm. POLYM. ENG. SCI., 47:477–480, 2007. © 2007 Society of Plastics Engineers.
Application of a capacitive transducer for online part weight prediction and fault detection in injection molding
Authors: Fung Ka Tsai , Gao Furong , Chen Xi 
Published: March 2007

AbstractThis article extends the applications of in‐mold capacitive transducer to packing stage for on‐line part weight prediction and check‐ring failure detection for injection molding. Experiments under various conditions show that the proposed on‐line part weight prediction is robust and effective, which may pave the way for on‐line closed‐loop part weight control. POLYM. ENG. SCI., 47:347–353, 2007. © 2007 Society of Plastics Engineers.
Nonisothermal crystallization behavior of poly(ϵ‐caprolactone)/attapulgite nanocomposites by DSC analysis
Authors: Liu Qi , Peng Zhiqin , Chen Dajun 
Published: March 2007

AbstractNanocomposites based on biodegradable poly(ε‐caprolactone) (PCL) and attapulgite (AT) were prepared by solution mixing. The nonisothermal crystallization of the pure PCL and PCL/AT nanocomposites at different AT contents and different cooling rates were investigated by differential scanning calorimetry (DSC). There are significant dependence of nonisothermal crystallization behavior and kinetics of PCL/AT nanocomposites on the AT content and cooling rate. The Jeziorny method has been employed to analyze the DSC data. The results show that Jeziorny method could describe this system well. It can be concluded that AT can be used as an effective nucleating agent and has effects on the growth of crystallites in the crystallization process of PCL matrix. POLYM. ENG. SCI., 47:460–466, 2007. © 2007 Society of Plastics Engineers.
Effect of nucleating additives on crystallization of poly(m‐xylylene adipamide)
Authors: Naudy Sophie , Fulchiron René 
Published: March 2007

AbstractStatic crystallization study was carried out on virgin and nucleated poly(m‐xylylene adipamide) (MXD6) which were, respectively, named PA1 and PA2. For PA2, the nucleating additives consist in talc (1%) and PA66 (11%). The three used experimental techniques (rheometer, calorimetry, and a hot stage coupled with an optical microscope) showed complementary results as the DSC could not be used to measure the low crystallization kinetics of PA1. Characteristic crystallization times were measured according to the crystallization conditions (temperature, cooling rate). Isothermal crystallization study allowed the determination of the thermodynamic melting point of the MXD6 and the description of the lamellae growth rate by the Hoffman–Lauritzen equation. For PA2, the creation of a soft network due to PA66 crystallization prior to the MXD6 crystallization was highlighted thanks to a specific rheological study. Lastly, kinetic models, based on both Avrami and Hoffman–Lauritzen theories, were proposed to depict the crystallization process. POLYM. ENG. SCI., 47:365–373, 2007. © 2007 Society of Plastics Engineers.
Influence of wall thickness on the creep rupture performance of polyethylene pipe
Authors: Krishnaswamy Rajendra K. 
Published: March 2007

AbstractA thermal gradient is inherent to the solidification of extruded profiles such as pipes. Depending on the magnitude of the gradient, varying levels of residual stresses are frozen‐in during the pipe fabrication step. In this investigation, the residual stress state of a polyethylene (PE) pipe was altered by changing its wall thickness. Creep rupture testing of the subject pipes of varying wall thickness provided an insight on how residual stresses influences both ductile and brittle fracture processes. POLYM. ENG. SCI., 47:516–521, 2007. © 2007 Society of Plastics Engineers.
Crystallization kinetics and morphology of the mesomorphic form of syndiotactic polypropylene
Authors: Pucciariello Rachele , Villani Vincenzo , Cascone Alfonso , Guadagno Liberata , Vittoria Vittoria 
Published: March 2007

AbstractFor the first time the kinetics of formation of syndiotactic polypropylene mesophase close to 0 °C through differential scanning calorimetry has been investigated. The calorimetric data have been analyzed through the well‐known Avrami analysis. We have obtained Avrami coefficients less or at most equal to 2, which are likely to indicate a nearly bidimensionality of the crystallites. The morphology of the mesophase, not known up to now, has been examined through atomic force microscopy (AFM): lamellar structures have been observed. The fractal dimension of the AFM images has been evaluated through the box counting method. It resulted about 2, in a very good agreement with the calculated Avrami coefficients. An infrared and diffractometer analysis on samples kept for increasing times at 0 °C has also been performed to confirm the calorimetric data. The experimental results allow one to better clarify the kinetics of mesophase‐formation. It has been found that a time of 3 h at 0 °C is actually necessary for the complete crystallization of the trans‐planar mesophase, a longer time is needed to stabilize the mesophase domains when the sample is extracted from 0 °C at room temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 936–944, 2007
Heterogeneity of glass transition dynamics in polyurethane‐poly(2‐hydroxyethyl methacrylate) semi‐interpenetrating polymer networks
Authors: Karabanova L. V. , Sergeeva L. M. , Svyatyna A. V. , Yakushev P. N. , Egorova L. M. , Ryzhov V. A. , Bershtein V. A. 
Published: March 2007

AbstractThe peculiarities of segmental dynamics over the temperature range of −140 to 180 °C were studied in polyurethane‐poly(2‐hydroxyethyl methacrylate) semi‐interpenetrating polymer networks (PU‐PHEMA semi‐IPNs) with two‐phase, nanoheterogeneous structure. The networks were synthesized by the sequential method when the PU network was obtained from poly(oxypropylene glycol) (PPG) and adduct of trimethylolpropane (TMP) and toluylene diisocyanate (TDI), and then swollen with 2‐hydroxyethyl methacrylate monomer with its subsequent photopolymerization. PHEMA content in the semi‐IPNs varied from 10 to 57 wt %. Laser‐interferometric creep rate spectroscopy (CRS), supplemented with differential scanning calorimetry (DSC), was used for discrete dynamic analysis of these IPNs. The effects of anomalous, large broadening of the PHEMA glass transition to higher temperatures in comparison with that of neat PHEMA, despite much lower Tg of the PU constituent, and the pronounced heterogeneity of glass transition dynamics were found in these networks. Up to 3 or 4 overlapping creep rate peaks, characterizing different segmental dynamics modes, have been registered within both PU and PHEMA glass transitions in these semi‐IPNs. On the whole, the united semi‐IPN glass transition ranged virtually from −60 to 160 °C. As proved by IR spectra, some hybridization of the semi‐IPN constituents took place, and therefore the effects observed could be properly interpreted in the framework of the notion of “constrained dynamics.” The peculiar segmental dynamics in the semi‐IPNs studied may help in developing advanced biomedical, damping, and membrane materials based thereon. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 963–975, 2007
Effect of tube length on the chemisorptions of one and two hydrogen atoms on the sidewalls of (3,3) and (4,4) single‐walled carbon nanotubes: A theoretical study
Authors: Kaczmarek Anna , Dinadayalane T. C. , Łukaszewicz Jerzy , Leszczynski Jerzy 
Published: March 2007

AbstractDensity functional theory (B3LYP) calculations using 3‐21G and 6‐31G(d) basis sets were performed for four different lengths of (3,3) and (4,4) armchair single‐walled carbon nanotubes to examine the effect of tube length on the chemisorption process. The significant changes in the CC bond lengths by H‐chemisorption are due to the change of hybridization of carbon atom(s) from sp2 to sp3 at the chemisorption site(s). In general, 3‐21G basis set overestimates the bond distances and reaction exothermicities compared to 6‐31G(d) basis set; however, both the basis sets reveal similar trend. The exothermicity for the addition of two H atoms is about 2–2.5 times that of one H chemisorption except for H (1,3) addition. The present study reveals that the positional preference for the chemisorption of two hydrogen atoms is not same for the armchair and zigzag type nanotubes. The reaction energies for hydrogen chemisorption on the surface of (3,3) nanotubes are substantially higher than for (4,4) SWNTs, probably due to the greater curvature and larger strain in the former case. The change of tube length has significant effect on the reaction energies of hydrogen chemisorption and band gap values. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
The Bacterial Two-Hybrid System as a Reporter System for Analyzing Protein-Protein Interactions
Authors: Giesecke Astrid V. , Joung J. Keith 
Published: March 2007

INTRODUCTIONThe bacterial two-hybrid system provides a convenient method for rapidly and quantitatively assessing the effect of specific mutations on protein-protein interactions. It is well suited to analyzing series of mutants (e.g., those generated from alanine scanning experiments or comprehensive mutagenesis of DNA-binding sites). The Escherichia coli lacZ gene (encoding β-galactosidase) serves as a reporter gene because its expression is easily measured using a quantitative assay. This protocol describes methods for assessing the interaction of hypothetical proteins X and Y in the bacterial two-hybrid system. Plasmids expressing the hybrid proteins DBD-X and RNAP-Y are constructed. Protein X can be fused either to a monomeric DBD (the zinc finger domain from the Zif268 protein) or to the dimeric bacteriophage λcI repressor protein. Protein Y can be fused either to the monomeric E. coli RNAP ω-subunit or to the dimeric E. coli RNAP α. Plasmids encoding these hybrid proteins are used to transform an appropriate lacZ reporter strain. Quantitative β-galactosidase assays are performed to measure the effect of the two-hybrid proteins on reporter gene expression. Following successful demonstration of X-Y interaction in this system, these protocols can be used to assess the effects of mutations on the interaction of X and Y.