bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asymmetric 1,3‐Dipolar Cycloaddition Reaction between α,β‐Unsaturated Aldehydes and Nitrones Catalyzed by Well‐Defined Iridium or Rhodium Catalysts
Authors: Carmona Daniel , Lamata M. Pilar , Viguri Fernando , Rodríguez Ricardo , Fischer Thomas , Lahoz Fernando J. , Dobrinovitch Isabel T. , Oro Luis A. 
Published: July 2007

AbstractReaction of the complexes (SM,RC)‐[(η5‐C5Me5)M{(R)‐Prophos}(H2O)](SbF6)2 (M=Rh, Ir) with α,β‐unsaturated aldehydes diastereoselectively gave complexes (SM,RC)‐[(η5‐C5Me5)M{(R)‐Prophos}(enal)](SbF6)2 which have been fully characterized, including an X‐ray molecular structure determination of the complex (SRh,RC)‐[(η5‐C5Me5)Rh{(R)‐Prophos}(trans‐2‐methyl‐2‐pentenal)](SbF6)2. These enal complexes efficiently catalyze the enantioselective 1,3‐dipolar cycloaddition of the nitrones N‐benzylideneaniline N‐oxide and 3,4‐dihydroisoquinoline N‐oxide to the corresponding enals. Reactions occur with excellent regioselectivity, perfect endo selectivity and with enantiomeric excesses up to 94 %. The absolute configuration of the adduct 5‐methyl‐2,3‐diphenylisoxazolidine‐4‐carboxaldehyde was determined through its (R)‐(−)‐α‐methylbenzylamine derivative.
Nitrilase‐Catalyzed Selective Hydrolysis of Dinitriles and Green Access to the Cyanocarboxylic Acids of Pharmaceutical Importance
Authors: Zhu Dunming , Mukherjee Chandrani , Biehl Edward R. , Hua Ling 
Published: July 2007

AbstractTo further explore its synthetic applications, the nitrilase bll6402 from Bradyrhizobium japonicum strain USDA110 has been examined toward the hydrolysis of various dinitriles. It has been found that nitrilase bll6402 effectively hydrolyzed α,ω‐dinitriles to ω‐cyanocarboxylic acids, and the selectivity was independent of the substrate chain length. This feature is distinct from all the known nitrilases of various sources. Nitrilase bll6402 was thus applied to the synthesis of 1‐cyanocycloalkaneacetic acids, the useful precursors for the synthesis of gabapentin and its analogues.
Highly Enantioselective Transfer Hydrogenation of α‐Imino Esters by a Phosphoric Acid
Authors: Kang Qiang , Zhao Zhuo‐An , You Shu‐Li 
Published: July 2007

AbstractChiral phosphoric acids have been identified as highly efficient organocatalysts for the asymmetric transfer hydrogenation of α‐imino esters and amide. Utilizing Hantzsch esters as the hydrogen donor, versatile highly enantioenriched α‐amino esters and their derivatives were obtained with up to 98 % ee.
Genetic factors in physical growth and development and their relationship to subsequent health outcomes
Authors: Czerwinski Stefan A. , Lee Miryoung , Choh Audrey C. , Wurzbacher Keith , Demerath Ellen W. , Towne Bradford , Siervogel Roger M. 
Published: July 2007

AbstractNormal physical growth during childhood is influenced by both genetic and environmental factors. However, few studies have examined whether there are shared genetic effects between aspects of child growth and later health outcomes. In this study, we estimate the influence of genetic factors on growth in stature during childhood and determine whether there are pleiotropic effects of genes influencing both childhood growth and later adult health outcomes using familial data. Serial stature data (i.e., birth through adulthood) from participants in the Fels Longitudinal Study were used to derive stature growth parameters. Adult health outcome data for each participant were available for at least one visit after age 30 years. Maximum likelihood‐based variance component methods were used to determine the heritability of each parameter and to examine the relationships between growth parameters and adult health outcomes by estimating genetic correlations between the traits. Heritability estimates for the growth parameters are generally high and statistically significant ranging in magnitude from 0.65–0.98. Heritabilities for adult health outcomes are also significant ranging from 0.31–0.98. Results of the phenotypic correlation analysis show that stature growth parameters are significantly related to several adult health outcomes including stature, weight, BMI, systolic and diastolic blood pressure, percent body fat, fat‐free mass, skeletal muscle mass in the arms and legs, and total body bone mass. Results of the genetic correlation analysis reveal some evidence of common genetic pathways underlying certain aspects of growth and adult health outcomes including body composition and blood pressure variables. Am. J. Hum. Biol., 2007. © 2007 Wiley‐Liss, Inc.
Adverse environments: Investigating local variation in child growth
Authors: Moffat Tina , Galloway Tracey 
Published: July 2007

AbstractEpigenetic and life history approaches to child growth are centered on the relationship between the organism and its environment. However, defining and operationalizing the concept of environment is challenging, in light of the multiple variables that influence growth. Moreover, the concept of adaptation as it applies to child growth is seldom considered in the developed country context. This paper presents a study of children living in three neighborhoods in the City of Hamilton, Ontario, Canada. Two of the communities are considered adverse environments on the basis of low socioeconomic status, and their inner city, industrial location. In contrast to children living in the higher socioeconomic status area, children in these adverse environments display negative growth indicators, i.e., somewhat constrained linear growth in one and risk for overweight and obesity in both. Although both these inner city neighborhoods constitute adverse environments, they differ in ways that have a significant impact on children's growth. We argue for a definition of “adverse environment” that is broadly based, incorporating a range of physical, social, and temporal factors that are highly localized and sensitive to community‐level influences on growth and health. As well, we consider whether higher prevalence of overweight and obesity is adaptive in any way to these adverse environments and conclude that they are more likely to be deleterious than adaptive in either the long or short term. Am. J. Hum. Biol., 2007. © 2007 Wiley‐Liss, Inc.
Tradeoffs between oxygen and energy in tibial growth at high altitude
Authors: Bailey S.M. , Xu J. , Feng J.H. , Hu X. , Zhang C. , Qui S. 
Published: July 2007

AbstractSome studies of high altitude populations argue that stature reduction results from caloric, rather than hypoxic, stress. However, tradeoff models of oxygen and glucose metabolism predict that in hypoxemia, glucose metabolism will be downregulated. We used tradeoff assumptions in two hypotheses: First, that hypoxia targets leg segment growth differentially, and second, that proportions of leg segments partition the impact of high altitude into hypoxemic and energetic components. A group of 113 Han and Tibetan middle school children at 3100 m aged 8 to 11 were measured for segment anthropometries, skinfolds, vital capacity, blood oxygen saturation, and percent body fat. MANOVA showed that Tibetan children were significantly larger and fatter than Han children. Independent of ethnicity or caloric status, absolute and relative tibia length was significantly reduced in children with lower blood oxygen saturation. Height, chest circumference, sitting height, tibia length, and ankle diameter were greatest in fatter children, independent of ethnicity or blood oxygen. For children of either ethnicity with the lowest blood oxygen, size as well as proportion was impacted. These results support the tradeoff model. Caloric reserves and ethnicity independently affect total skeletal size. Oxygen saturation and ethnicity affect leg proportions. In hypoxemia, body fat has less impact on growth than when ample oxygen is present. Therefore, we should qualify the claim that size in high altitude populations stems from nutritional stress. The findings also suggest that decanalization may have different meanings and outcomes depending on which body segments contribute to the effect. Am. J. Hum. Biol., 2007. © 2007 Wiley‐Liss, Inc.
The influence of pressure and temperature on coal pyrolysis/gasification
Authors: Chen Hanping , Yang Haiping , Ju Fudong , Wang Jing , Zhang Shihong 
Published: July 2007

AbstractThe aim of the study is mainly to understand the effect of pressure and temperature on the property of coal particles in pyrolysis/gasification. The pyrolysis of Shenfu (SF) coal sample and the gasification of resultant char were carried out in a thermogravimetric analyzer (TGA) under pressurized and ambient conditions. The gas released from coal pyrolysis was analyzed using a portable FTIR spectrometer connected to the TGA. Simultaneously, the surface structure and main chemical compounds of the pyrolyzed char particles were analyzed using gas sorption (ASAP2020), CNHS, etc. analysis instruments. First, the pyrolysis of SF coals was carried out in a pressurized TGA at various pressures (0.1, 0.8, 1.5, 3 and 5 Mpa) with a heating rate of 10 °C min−1 and a final temperature of 1000 °C. It was observed that higher pressures accelerated the devolatilization of coal samples at lower temperatures (<500 °C), while the maximum mass loss rate was reduced, and the solid char yield increased with increasing pressure. The specific surface area and chemical components changed with changing system pressure. The gasification reactivity of the solid char particles obtained was analyzed using ambient thermal balance at 1000 °C, using CO2 as the gasifying agent. The gasification reactivity increased with increasing pyrolysis pressure. Then the pyrolysis of SF coal was carried out under different temperatures (500, 650, 800 and 1000 °C) at ambient and higher pressures (3 Mpa). With increasing temperature, the gas product from coal pyrolysis enhanced greatly at the expense of decreasing charcoal residue. The surface area of the char particles obtained were minimum at 800 °C (ambient pressure) and at 600 °C (3 Mpa). The gasification reactivity of solid charcoal residues decreased considerably with increasing pyrolysis temperature at ambient pressure, while at 3 Mpa a different result was obtained, with the highest gasification reactivity at 800 °C. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Interfacial adhesion of plasma‐treated carbon fiber/poly(phthalazinone ether sulfone ketone) composite
Authors: Lu Chun , Chen Ping , Yu Qi , Ding Zhenfeng , Lin Zaiwen , Li Wei 
Published: July 2007

AbstractInterfacial adhesion between fiber and matrix has a strong influence on composite mechanical performance. To exploit the reinforcement potential of the fibers in advance composite, it is necessary to reach a deeper understanding on the relation between fiber surface treatment and interfacial adhesion. In this study, air plasma was applied to modify carbon fiber (CF) surface, and the capability of plasma grafting for improving the interfacial adhesion in CF/thermoplastic composite was discussed and also the mechanism for composite interfacial adhesion was analyzed. Results indicated that air plasma treatment was capable of increasing surface roughness as well as introducing surface polar groups onto CF; both chemical bonding and mechanical interaction were efficient in enhancements of interlaminate shear strength of CF/PPESK composite, while mechanical interaction has a dominant effect on composite interfacial adhesion than chemical bonding interaction. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Thermoforming process of amorphous polymeric sheets: Modeling and finite element simulations
Authors: Makradi A. , Belouettar S. , Ahzi S. , Puissant S. 
Published: July 2007

AbstractA temperature and strain rate dependent model for the thermoforming process of amorphous polymer materials is proposed. The polymeric sheet is heated at a temperature above the glass transition temperature then deformed to take the mold shape by the means of an applied pressure. The applied process temperature is taken uniform throughout the sheet and its variation is due only to the adiabatic heating. The behavior of the polymeric material is described by a micromechanically‐based elastic‐viscoplastic model. The simulations are conducted for the poly(methyl methacrylate) using the finite element method. The polymer sheet thickness and the orientation of the polymer molecular chains show an important dependence on the process temperature, the applied pressure profile, and the contact forces with the mold surface. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Engineering and utilizing a stopword list in Greek Web retrieval
Authors: Lazarinis Fotis 
Published: July 2007

AbstractThe main aim of the article is the presentation of the construction process of a stopword list for a non‐Latin language and the evaluation of the effect of stopword elimination from user queries. The article presents the phases of engineering a stopword list for the Greek language as well as the problems faced and the inferences deduced from this procedure. A set of 32 authentic queries are proposed by users and are run in Google with and without the stopwords. The importance of eliminating the stopwords from the user queries is then evaluated, in terms of relevance, in the top‐10 results from Google.
Electron‐Transfer Properties and Active‐Site Structure of the Type 1 (Blue) Copper Protein Umecyanin
Authors: Dennison Christopher , Van Driessche Gonzalez , Van Beeumen Jos , McFarlane William , Geoffrey Sykes A. 
Published: July 2007

AbstractThe electron self‐exchange rate constant for the Type 1 blue copper protein umecyanin from horseradish roots has been determined as 6.1 × 103 M−1 S−1 at pH 7.5, I = 0.100 M, 25°C by an NMR line‐broadening method. The value obtained is one of the lower self‐exchange rate constants determined for this class of protein; this is attributed to the presence of positively charged residues near to the electron‐transfer site. The self‐exchange rate constants calculated by means of a Marcus analysis of data for the cross‐reactions (25°C) of umecyanin with azurin and cytochrome c551 (both from Pseudomonas aeruginosa) are substantially less at 8.0M−1 S−1 and 13.9M−1S−1, respectively, and are independent of pH in the range 7.0–8.0, I = 0.100M. The discrepancy between the self‐exchange rate constants obtained by these two different methods can be rationalised if it is assumed that umecyanin reacts with the two proteins employed in the cross‐reaction studies through the same site, but that this site is different from that used for the self‐exchange process. A comparison of the primary structure of umecyanin with those of other Type 1 copper proteins has revealed that a glutamine rather than a methionine is likely as the fourth ligand of Cu at the active site. Other comparisons are made with stellacyanin, and the electron‐transfer reactivity of the two proteins is discussed.
Molecular Dynamics with a Quantum‐Chemical Potential: Solvent Effects on an SN2 Reaction at Nitrogen
Authors: Liu Haiyan , Müller‐Plathe Florian , van Gunsteren Wilfred F. 
Published: July 2007

AbstractSolvent effects on an SN2 reaction at nitrogen (Cl− + NH2Cl → ClNH2 + Cl−) in dimethyl ether solution were studied by means of molecular dynamics simulation with a combined quantum‐chemical and molecular‐mechanical potential. The energetics and geometrical parameters of the reaction in the gas phase, calculated by means of the semiempirical model PM3(the quantum chemical part of the combined potential), were compared with ab initio calculations up to the 6‐311 + G* */MP2 and 6‐311 + G(2 d,p)/MP2 levels of theory. Compared with the gas phase potential energy surface, the free energy profile of the reaction in dimethyl ether solution shows that the solvent makes the ion‐dipole complex well shallower by approximately 6.4 kcal mol−1 and raises the height of the effective barrier from the complex to the transition state by about 2.2 kcal mol−1. The overall transition barrier between the separated reactants and the products is raised from 6.4 kcal mol−1 to 15.0 kcal mol−1 upon solvation. The radial distribution functions between solvent‐solute atom pairs at different stages of the reaction course were compared. Results show that better solvation of the charge‐localised separated reactants is responsible for the increase in the barrier height. Polarisation of the solute by its surroundings is also discussed.
Ionic Fluorination of Carbon Monoxide as a Route to Gasphase Carbonylation of Inert CH and NH Bonds
Authors: Grandinetti Felice , Pepi Federico , Ricci Andreina 
Published: July 2007

AbstractGaseous FCO+ ions from the ionization of mixtures of nitrogen trifluoride and carbon monoxide execute selective and efficient CO‐functionalization of the C–H bonds of benzene and toluene and of the N–H bond of ammonia. The occurrence of these carbonylation reactions has been unambiguously ascertained by Fourier‐transform ion cyclotron resonance (FT‐ICR) spectrometry, and the details of the structure and the mechanism of formation of the precursor FCO+ ions have been investigated. FT‐ICR experiments show that these ions, structurally assigned as F–C–O+ by collisionally activated dissociation (CAD) spectrometry, arise from the reaction of CO.+ with NF3 and of NF+2 with CO. Combining the latter F+ transfer with the independently observed fluoride‐ion abstraction by FCO+ from NF3 results in a catalytic cycle in which gaseous NF+2 ions promote the conversion of carbon monoxide into carbonic difluoride, F2CO, with nitrogen trifluoride as the source of F.
Giant Magnetoresistance Phenomenon in Manganates
Authors: Rao C. N. R. 
Published: July 2007

AbstractThe discovery of giant magnetoresistance (GMR) in rare earth manganates of the general formula Ln1–xAxMnO3 (Lnrare earth, A=divalent cation) has aroused much interest not only because of its technological implications, but also due to the fascinating features and mechanism of the phenomemon in these oxides. GMR is observed in these manganates when they become ferromagnetic and transform from an insulating state to a metallic state close to the Curie temperature. The essential features of magnetoresistance in the manganates can be understood on the basis of the double‐exchange mechanism, but this is too simplistic to account for all the observed data. The most curious property of the manganates relates to the high resistivity exhibited in the so‐called metallic state. Charge ordering competes with the double‐exchange interaction responsible for ferromagnetism and GMR in these materials. The charge‐ordered (charge‐crystal) insulating state in the rare earth manganates can be melted into a metallic and ferromagnetic charge‐liquid state by applying a magnetic field, thus providing a unique case of charge and spin separation in solids. The observation of GMR in Tl2Mn2O7 shows that there can be causes other than double‐exchange for the phenomenon.
Synthesis of a Pentasaccharide–Oligonucleotide Conjugate: A Novel Antithrombotic Agent
Authors: Buijsman Rogier C. , Kuijpers Will H. A. , Basten Jan E. M. , Kuyl‐Yeheskiely Esther , van der Marel Gijsbert A. , van Boeckel Constant A. A. , van Boom Jacques H. 
Published: July 2007

AbstractDerivatization of the octadecathymidylate derivative 18 (T18 ODN) containing a free amine function with sulfo‐SIAB® gave the corresponding iodoacetyl ODN 21. Conjugation of the latter with the thiol‐containing pentasaccharide 17c gave pentasaccharide–ODN conjugate III, which exhibited anti‐Xa and antithrombin activities of 173 U mg‐1 and 5 U mg‐1, respectively.
Clinical stage after preoperative chemoradiation is a better predictor of patient outcome than the baseline stage for localized gastric cancer
Authors: Patel Pooja R. , Mansfield Paul F. , Crane Christopher H. , Wu Tsung‐Teh , Lee Jeffrey H. , Lynch Patrick M. , Morris Jeffrey , Pisters Peter W. , Feig Barry , Sunder Punita K. , Izzo Julie G. , Ajani Jaffer A. 
Published: July 2007

AbstractBACKGROUND.For patients with localized gastric cancer (LGC) who are receiving preoperative chemoradiation (CTRT), the postsurgical pathologic stage predicts overall survival (OS) better than the baseline stage. The authors hypothesized that presurgical (postCTRT) stage would also correlate better with patient outcome than the baseline stage.METHODS.The authors analyzed 74 LGC patients treated with preoperative CTRT receiving similar treatment. Patients were staged with baseline endoscopic ultrasonography (EUS) and laparoscopy. Patients received induction chemotherapy, then CTRT (45 Gy), and had an attempted surgery. After CTRT, patients had complete preoperative staging including EUS in 35 patients.RESULTS.Thirty‐five had all 3 sets of staging, baseline, presurgical, and postsurgical. Baseline stage did not associate with OS (P = .16) nor disease‐free survival (DFS; P = .13). However, presurgical stage was associated with OS (P = .01), and DFS (P = .05). OS was also associated with postsurgical stage and was longer for stages 0 and I than for stages III and IV (P = .01 and .04, respectively). Similarly, DFS was longer in postsurgical pathologic stages 0, I, and II than in stage III or IV (P < .001, <.001, and <.01, respectively). Baseline staging did not correlate with the proportion of patients alive at 4 years; however, presurgical staging did. Patients with stage I or II survived longer than those with stage III or IV (81% vs 25%; P < .01).CONCLUSIONS.Heterogeneity in clinical biology of LGC is best reflected after CTRT in presurgical and postsurgical pathologic stages rather than by the baseline stage. Correlation of outcome with presurgical staging may facilitate strategies to individualize therapy for LGC. Cancer 2007. © 2007 American Cancer Society.
An efficient hourglass control implementation for the uniform strain hexahedron using the Total Lagrangian formulation
Authors: Joldes Grand Roman , Wittek Adam , Miller Karol 
Published: July 2007

AbstractThe under‐integrated hexahedron is one of the best candidates for use in real‐time surgical simulations, because of its computational efficiency. This element requires a very efficient method of controlling the zero energy (hourglass) modes that arise from one‐point integration. An efficient implementation of the perturbation hourglass control method proposed by Flanagan and Belytschko for the uniform strain hexahedron is presented. The implementation uses the Total Lagrangian formulation and takes into consideration large deformations and rigid body motions. By using the Total Lagrangian formulation most of the necessary components for calculating the hourglass forces can be pre‐computed, leading to a significant reduction of the additional computation time required for hourglass control. The performance evaluation results show the very good accuracy and computational efficiency of the presented algorithm. Copyright © 2007 John Wiley & Sons, Ltd.
Segregation and scheduling for P2P applications with the interceptor middleware system
Authors: Anglano Cosimo 
Published: July 2007

AbstractVery large size peer‐to‐peer systems are often required to implement efficient and scalable services, but usually they can be built only by assembling resources contributed by many independent users. Among the guarantees that must be provided to convince these users to join the P2P system, particularly important is the ability of ensuring that P2P applications and services run on their nodes will not unacceptably degrade the performance of their own applications because of an excessive resource consumption. In this paper we present the Interceptor, a middleware‐level application segregation and scheduling system, which is able to strictly enforce quantitative limitations on node resource usage and, at the same time, to make P2P applications achieve satisfactory performance even in face of these limitations. A proof‐of‐concept implementation has been carried out for the Linux operating system, and has been used to perform an extensive experimentation aimed at quantitatively evaluating the Interceptor. The results we obtained clearly demonstrate that the Interceptor is able to strictly enforce quantitative limitations on node resource usage, and at the same time to effectively schedule P2P applications. Copyright © 2007 John Wiley & Sons, Ltd.