bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of employability outcomes among patients with early or long‐standing rheumatoid arthritis
Authors: Han Chenglong , Smolen Josef , Kavanaugh Arthur , St.clair E. William , Baker Daniel , Bala Mohan 
Published: March 2008

AbstractObjectiveTo compare employability between patients with early and long‐standing rheumatoid arthritis (RA) and examine the relationships between improvement in employability and disease stage after adjustment for demographic characteristics, disease activity, physical functioning, and response to therapy.MethodsWe evaluated the employability data from 2 double‐blind, randomized, placebo‐controlled studies of infliximab plus methotrexate (MTX) in patients with RA. Patients were incomplete responders to MTX in 1 study and had never taken MTX in the other study. Patients age <65 years were categorized as having early RA (≤3 years disease duration) or long‐standing RA (>3 years disease duration). Physical functioning was assessed using the Health Assessment Questionnaire (HAQ) and clinical response was determined based on the American College of Rheumatology 20% improvement criteria (ACR20).ResultsPatients with early RA were more likely to be employable at baseline than those with long‐standing RA, even after adjusting for baseline HAQ scores. Among patients who were not employable at baseline but achieved an ACR20 response after 1 year of treatment, after adjusting for baseline HAQ score, the patients with early RA who had never taken MTX were 3 times more likely to become employable compared with those with long‐standing RA who had an incomplete response to MTX at baseline.ConclusionIn 2 clinical trials, patients with early RA were more likely to show improved employment outcomes after treatment than those with long‐standing RA, suggesting intervention as early as possible in the disease course maximizes an individual patient's employment potential.
Fabrication of Selenium/Carbon Core–Shell Submicrowires and Carbon Submicrotubes by a Facile Solution Process
Authors: Wang Weizhi , Qiu Sheng , Xi Baojuan , Chen Liyong , Xiong Shenglin , Zhang Zude 
Published: March 2008

AbstractWe show a facile one‐step surfactant‐assisted solution process to fabricate selenium/carbon (Se/C) coaxial core–shell submicrowires and their transformation into carbon submicrotubes by dissolution of the Se cores at ambient temperature. The formation process of the Se/C core–shell submicrowires was investigated. The results of the investigation and further experiments confirm that the thickness of the carbon shell could be tailored by controlling the experimental conditions. The as‐synthesized Se/C core–shell submicrowires and the carbon submicrotubes are potentially useful in applications such as in nanodevices or biomedicine.
A General Approach for Sample Size and Power Calculations Based on the Haseman–Elston Method
Authors: Hädicke Oliver , Pahlke Friedrich , Ziegler Andreas 
Published: March 2008

AbstractRisch and Zhang (1995; Science 268: 1584‐9) reported a simple sample size and power calculation approach for the Haseman–Elston method and based their computations on the null hypothesis of no genetic effect. We argue that the more reasonable null hypothesis is that of no recombination. For this null hypothesis, we provide a general approach for sample size and power calculations within the Haseman–Elston framework. We demonstrate the validity of our approach in a Monte‐Carlo simulation study and illustrate the differences using data from published segregation analyses on body weight and heritability estimates on carotid artery artherosclerotic lesions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Simple Numerical Approach Towards Improving the Two One‐Sided Test for Average Bioequivalence
Authors: Cao Li , Mathew Thomas 
Published: March 2008

AbstractFor testing average bioequivalence, a simple test that improves upon the two‐one sided test (TOST) is derived. The new test uses a critical value that is a non‐increasing continuous function of the sample standard deviation, and the function is numerically obtained. Simulation results show that the resulting test performs well in terms of type I error probability; in particular, the test avoids the conservatism of the TOST. Consequently, the test provides better power compared to the TOST, especially when the variance becomes large. Numerical results also show that our test results in power that is very similar to the other improved tests available in the literature. An advantage of our improved test is that it is just as easy to carry out as the TOST. An example is used to illustrate the new test. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inferences About the Between‐Study Variance in Meta‐Analysis with Normally Distributed Outcomes
Authors: Tian Lili 
Published: March 2008

AbstractThis paper presents a new approach for confidence interval estimation of the between‐study variance in meta‐analysis with normally distributed responses based on the concepts of generalized variables. Simulation study shows that the coverage probabilities of the proposed confidence intervals are generally satisfactory. Moreover, the proposed approach can easily provide P ‐values for hypothesis testing. For meta‐analysis of controlled clinical trials or epidemiological studies, within which the responses are normally distributed, the proposed approach is an ideal candidate for making inference about the between‐study variance. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nearest Neighbour Adjustment and Linear Variance Models in Plant Breeding Trials
Authors: Piepho Hans‐Peter , Richter Christel , Williams Emlyn 
Published: March 2008

AbstractThis paper reviews methods for nearest neighbour analysis that adjust for local trend in one dimension. Such methods are commonly used in plant breeding and variety testing. The focus is on simple differencing methods, including first differences and the Papadakis method. We discuss mixed model representations of these methods on the scale of the observed data. Modelling observed data has a number of practical advantages compared to differencing, for example the facility to conveniently compute adjusted cultivar means. Most models considered involve a linear variance‐covariance structure and can be represented as state‐space models. The reviewed methods and models are exemplified using three datasets. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Inner‐Shell Film: An Immediate Structure Participating in Pearl Oyster Shell Formation
Authors: Yan Zhenguang , Ma Zhuojun , Zheng Guilan , Feng Qiaoli , Wang Hongzhong , Xie Liping , Zhang Rongqing 
Published: March 2008

AbstractIn mollusks, the inner shell film is located in the shell‐mantle zone and it is important in shell formation. In this study, we found that the film was composed of two individual films under certain states and some columnar structures were observed between the two individual films. The inner shell film was separated with the process of ethylenediaminetetraacetic acid (EDTA) treatment and the film proteins were extracted. Amino acid analysis showed that the film proteins may consist of shell framework proteins. The calcite crystallization experiment showed that the film proteins could inhibit the growth of calcite, while the CaCO3precipitation experiment showed that the film proteins could accelerate the rate of CaCO3precipitation. All these results suggested that the film plays an important role in shell formation. It may facilitate the aragonite formation by inhibiting the growth of calcite and accelerate the shell growth by promoting the precipitation of CaCO3crystals.
Control of Porosity Geometry in Amino Acid Derived Nanoporous Materials
Authors: Perez Barrio Jorge , Rebilly Jean‐Noël , Carter Benjamin , Bradshaw Darren , Bacsa John , Ganin Alexey Y. , Park Hyunsoo , Trewin Abbie , Vaidhyanathan Ramanathan , Cooper Andrew I. , Warren John E. , Rosseinsky Matthew J. 
Published: March 2008

AbstractSubstitution of the pillaring ligand in the homochiral open‐framework [Ni2(L‐asp)2(bipy)] by extended bipy‐type ligands leads to a family of layer‐structured, homochiral metal‐organic frameworks. The 1D channel topology can be modified by the nature of the organic linker, with shape, cross‐section and the chemical functionality tuneable. In addition, the volume of these channels can be increased by up to 36 % compared to the parent [Ni2(L‐asp)2(bipy)]. The linker 1,4‐dipyridylbenzene (3rbp) gives access to a new layered homochiral framework [Ni2(L‐asp)2(3rbp)] with channels of a different shape. In specific cases, non‐porous analogues with the linker also present as a guest can be activated to give porous materials after sublimation. Their CO2 uptake shows an increase of up to 30 % with respect to the parent [Ni2(L‐asp)2(bipy)] framework.
Copper(II) Coordination Chemistry of Westiellamide and Its Imidazole, Oxazole, and Thiazole Analogues
Authors: Comba Peter , Gahan Lawrence R. , Haberhauer Gebhard , Hanson Graeme R. , Noble Christopher J. , Seibold Björn , van den Brenk Anna L. 
Published: March 2008

AbstractThe copper(II) coordination chemistry of westiellamide (H3Lwa), as well as of three synthetic analogues with an [18]azacrown‐6 macrocyclic structure but with three imidazole (H3L1), oxazole (H3L2), and thiazole (H3L3) rings instead of oxazoline, is reported. As in the larger patellamide rings, the Nheterocycle‐Npeptide‐Nheterocycle binding site is highly preorganized for copper(II) coordination. In contrast to earlier reports, the macrocyclic peptides have been found to form stable mono‐ and dinuclear copper(II) complexes. The coordination of copper(II) has been monitored by high‐resolution electrospray mass spectrometry (ESI‐MS), spectrophotometric and polarimetric titrations, and EPR and IR spectroscopies, and the structural assignments have been supported by time‐dependent studies (UV/Vis/NIR, ESI‐MS, and EPR) of the complexation reaction of copper(II) with H3L1. Density functional theory (DFT) calculations have been used to model the structures of the copper(II) complexes on the basis of their spectroscopic data. The copper(II) ion has a distorted square‐pyramidal geometry with one or two coordinated solvent molecules (CH3OH) in the mononuclear copper(II) cyclic peptide complexes, but the coordination sphere in [Cu(H2Lwa)(OHCH3)]+ differs from those in the synthetic analogues, [Cu(H2L)(OHCH3)2]+ (L=L1, L2, L3). Dinuclear copper(II) complexes ([CuII2(HL)(μ‐X)]+; X=OCH3, OH; L=L1, L2, L3, Lwa) are observed in the mass spectra. While a dipole–dipole coupled EPR spectrum is observed for the dinuclear copper(II) complex of H3L3, the corresponding complexes with H3L (L=L1, L2, Lwa) are EPR‐silent. This may be explained in terms of strong antiferromagnetic coupling (H3L1) and/or a low concentration of the dicopper(II) complexes (H3Lwa, H3L2), in agreement with the mass spectrometric observations.
Nucleophilic Additions to Alkylidene Bis(sulfoxides)—Stereoelectronic Effects in Vinyl Sulfoxides
Authors: Wedel Tobias , Gehring Timo , Podlech Joachim , Kordel Elena , Bihlmeier Angela , Klopper Wim 
Published: March 2008

AbstractConjugate additions of nucleophiles (e.g. enolates, amines and malonate anions) to bis(p‐tolylsulfinyl)alkenes, alkylidene‐1,3‐dithiane‐1,3‐dioxides and alkylidene‐1,3‐dithiolane‐1,3‐dioxides have recently been published. Reasons for different selectivities and reaction rates will be discussed by consideration of steric and electronic effects. The preferred mode of attack can be explained by stereoelectronic effects (hyperconjugation) in the primarily carbanion, which is stabilized by n→S‐O‐σ* interaction with an antiperiplanar SO group. Calculation of the transition states [BP86/aug‐TZVP] for the addition of acetone enolate to the dithiane‐derived alkylidene bis(sulfoxide) revealed that 6.6–7.3 kJ mol−1 more energy is needed for an attack leading to a less‐stabilized carbanion. Two axial SO groups in dithiolane‐derived alkylidene bis(sulfoxides) lead to a higher reactivity towards nucleophiles.
Exploring Helical Folding of Oligoureas During Chain Elongation by High‐Resolution Magic‐Angle‐Spinning (HRMAS) NMR Spectroscopy
Authors: Violette Aude , Lancelot Nathalie , Poschalko Alexander , Piotto Martial , Briand Jean‐Paul , Raya Jesus , Elbayed Karim , Bianco Alberto , Guichard Gilles 
Published: March 2008

AbstractThe development of novel folding oligomers (foldamers) for biological and biomedical applications requires both precise structural information and appropriate methods to detect folding propensity. However, the synthesis and the systematic conformational investigation of large arrays of oligomers to determine the influence of factors, such as chain length, side chains, and surrounding environment, on secondary structure can be quite tedious. Herein, we show for 2.5‐helical N,N′‐linked oligoureas (γ‐peptide lineage) that the whole process of foldamer characterization can be accelerated by using high‐resolution magic‐angle‐spinning (HRMAS) NMR spectroscopy. This was achieved by monitoring a simple descriptor of conformational homogeneity (e.g., chemical shift difference between diastereotopic main chain CH2 protons) at different stages of oligourea chain growth on a solid support. HRMAS NMR experiments were conducted on two sets of oligoureas, ranging from dimer to hexamer, immobilized on DEUSS, a perdeuterated poly(oxyethylene)‐based solid support swollen in solvents of low to high polarity. One evident advantage of the method is that only minute amount of material is required. In addition, the resonance of the deuterated resin is almost negligeable. On‐bead NOESY spectra of high quality and with resolution comparable to that of liquid samples were obtained for longer oligomers, thus allowing detailed structural characterization.
Coordination Chemistry of the cyclo‐(P5tBu4)− Ion: Monomeric and Oligomeric Copper(I), Silver(I) and Gold(I) Complexes
Authors: Gómez‐Ruiz Santiago , Wolf Robert , Bauer Sebastian , Bittig Henry , Schisler Andrea , Lönnecke Peter , Hey‐Hawkins Evamarie 
Published: March 2008

Abstract[Na{cyclo‐(P5tBu4)}] (1) reacts with [CuCl(PCyp3)2] (Cyp=cyclo‐C5H9) and [CuCl(PPh3)3] (1:1) to give the corresponding copper(I) complexes with a tetra‐tert‐butylcyclopentaphosphanide ligand, [Cu{cyclo‐ (P5tBu4)}(PCyp3)2] (2) and [Cu{cyclo‐(P5tBu4)}(PPh3)2] (3). The CuCl adduct of 2, [Cu2(μ‐Cl){cyclo‐(P5tBu4)}(PCyp3)2] (4), was obtained from the reaction of 1 with [CuCl(PCyp3)2] (1:2). Compounds 2 and 3 rearrange, even at −27 °C, to give [Cu4{cyclo‐ (P4tBu3)PtBu}4] (5), in which ring contraction of the [cyclo‐(P5tBu4)]− anion has occurred. The reaction of 1 with [AgCl(PCyp3)]4 or [AgCl(PPh3)2] (1:1) leads to the formation of [Ag4{cyclo‐(P4tBu3)PtBu}4] (6). Intermediates, which are most probably mononuclear, “[Ag{cyclo‐(P5tBu4)}(PR3)2]” (R=Cyp, Ph) could be detected in the reaction mixtures, but not isolated. Finally, the reaction of 1 with [AuCl(PCyp3)] (1:1) yielded [Au{cyclo‐(P5tBu4)}(PCyp3)] (7), whereas an inseparable mixture of [Au3{cyclo‐(P5tBu4)}3] (8) and [Au4{cyclo‐(P4tBu3)PtBu}4] (9) was obtained from the analogous reaction with [AuCl(PPh3)]. Complexes 3–7 were characterised by 31P NMR spectroscopy, and X‐ray crystal structures were determined for 3–9.
Ring‐Closing Metathesis: Novel Routes to Aromatic Heterocycles
Authors: Donohoe Timothy J. , Fishlock Lisa P. , Procopiou Panayiotis A. 
Published: March 2008

AbstractOlefin metathesis has been established as an important and general reaction in synthetic organic chemistry. Recently, it has attracted interest as a powerful tool for the construction of aromatic heterocycles. The importance of heteroaromatic motifs in medicinal chemistry and biology, as well as the efficiency and wealth of metathesis transformations, have resulted in significant success in this rapidly developing area.
Studies on para‐selectivity and yield enhancement in zeolite catalyzed toluene nitration
Authors: Sreedhar I. , Reddy K. Suresh Kumar , Ramakrishna M. , Kulkarni S. J. , Raghavan K.V. 
Published: March 2008

AbstractThe nitration of toluene using solid acid catalyst is carried out in batch and semi‐batch reactors with or without continuous water withdrawal. The effect of process parameters viz., nature of catalyst, agitation speed, nitric acid‐toluene dispersion morphology, catalyst to toluene ratio, temperature, nitric acid dosing and boil‐up rates (BRs) on overall conversions, and para‐selectivity is investigated. The micro‐reaction environment around the catalyst particle and its influence on lattice aluminum transformation to achieve improved para‐selectivity has received special attention. These studies have established the importance of dispersion morphology of reactants and microenvironment around catalyst particles for achieving preferred conversion and para‐selectivity in toluene nitration.
Hydrosulphide oxidation pathways in oxic alkaline media containing iron/cerium oxide‐hydroxide
Authors: Petre Catalin F. , Larachi Faïçal 
Published: March 2008

AbstractThe oxidation kinetics of hydrosulphide by iron/cerium oxide‐hydroxide (FeCeOx) and dissolved oxygen (DO2) was studied at 0.1 MPa and 298 K in a batch slurry reactor. The oxidation of hydrosulphide by the FeCeOx/DO2 system proceeded via a combined heterogeneous–homogeneous pathway to yield zerovalent sulphur and thiosulphate. The role of dissolved oxygen was twofold: (i) it reoxidized the iron from Fe(II) to active Fe(III), (ii) it prompted the homogeneous oxidation of hydrosulphide to polysulphides and of polysulphides to thiosulphate. The Fe(III) in situ regeneration by DO2 showed that FeCeOx holds promise for a redox scrubbing process targeting the elimination of H2S from the Kraft mill effluents.
Modelling and process development for gaseous separation with silicone‐coated polymeric membranes
Authors: Jiang Xin , Kumar Ashwani 
Published: March 2008

AbstractThis paper proposes a permeance equation for vapour–permanent gas mixtures in a silicone‐coated polymeric membrane. The equation was derived from the Arrhenius relationship by combining an apparent activation energy and interaction parameter. Accurate values of transmembrane flux were obtained by incorporating this proposed equation, which was dependent on temperature and feed composition. The equation parameters were correlated with the experimental data of eight mixtures consisting of hydrocarbons such as ethylene, ethane, propylene and propane with nitrogen covering a broad range of temperature and concentration. A numerical integration scheme was used for developing a crossflow model utilizing the above equation, which allowed the estimation of product properties including the membrane plasticization cases. The study also reports examples of implementation of this approach in potential industrial applications for the recovery of ethylene and propylene from nitrogen.
Adsorption of mercaptan from model gasoline on 13X loaded with Zn2+
Authors: Yongping Zeng , Shengui Ju , Weihong Xing , Changlin Chen 
Published: March 2008

AbstractAdsorption of mercaptan on 13X loaded with Zn2+ from model gasoline was studied at different concentration and temperatures. The results indicate that high temperature and low concentration favour the removal of mercaptan from the model gasoline. The adsorptive amount of the untreated adsorbents loaded with Zn2+ is less than the treated with heat obviously, but the adsorbed amount is not enhanced distinctly by the way of increasing the treating temperature. A pseudo‐first‐order mechanism has been proposed to describe the adsorption in the model gasoline system. The desulphurizing capability increases due to the Zn2+ impregnated. With the concentration of Zn2+ higher, the adsorptive amount for ethanethiol increases. Adsorption mechanism shows that it is a chemical adsorption. Two different methods of regeneration were investigated.
Heterogeneous kinetics of oxidation of alcohols: PTC techniques
Authors: Sankarshana T. , Rao M. Bhagvanth 
Published: March 2008

Abstract2‐ethyl‐1‐hexanol, n‐heptanol, and n‐hexanol oxidation by potassium permanganate was carried out in a baffled stirred reactor under heterogeneous conditions using phase transfer techniques. Tricaprylylmethylammonium chloride (Aliquat 336) was employed as the phase transfer catalyst. Kinetics of the oxidation was investigated. The rate constants were determined by varying the concentration of the catalyst, the concentration of alcohols and temperature. The rate constants agree well with those obtained under homogeneous conditions for all the three alcohols. The variation in the values under heterogeneous conditions were found to be less than 6 %.
Energy‐efficient complex distillation sequences: Control properties
Authors: Robles‐Zapiain Salvador , Segovia‐Hernández Juan Gabriel , Bonilla‐Petriciolet Adrián , Maya‐Yescas Rafael 
Published: March 2008

AbstractFour thermally coupled distillation systems were designed for the separation of five‐component mixtures (the light‐ends separation section of a crude distillation plant); their steady‐state design was obtained by starting from a conventional distillation sequence and then optimizing for minimum energy consumption. The thermally coupled distillation systems were compared to sequence based on conventional columns design. Comparison was based on controllability properties under open and closed loop operation, following the dynamic behaviour after common industrial operating disturbances. Simulation results were analyzed by the singular value decomposition technique and with the performance examination of elimination of feed disturbances using PI controllers. It was found that thermally coupled distillation systems are controllable and, sometimes, they exhibit dynamic responses that are easier to manage than in the case of conventional distillation sequences; this result is innovative in the study of this kind of systems.
Alkylation of benzene with isopropanol over SAPO‐5: A kinetic study
Authors: Upadhyayula S. 
Published: March 2008

AbstractThe kinetics of benzene alkylation with isopropanol has been studied in vapour phase over SAPO‐5 catalyst. On the basis of the product distribution pattern obtained over this large pore molecular sieve, a reaction mechanism has been proposed. Based on this reaction network, suitable phenomenological models have been derived and fitted to the kinetic data. A Langmuir‐Hinshelwood model with surface reaction involving single site mechanism fitted the data better than the other models. The deactivation kinetics has also been investigated in the low temperature chosen. The activation energy for the deactivation reaction in this range is found to be lower than that for the main reaction.
Systems Biology: The synergistic interplay between biology and mathematics
Authors: Dhurjati Prasad , Mahadevan Radhakrishnan 
Published: March 2008

AbstractSystems Biology is a nascent field that arose from the technology driven omics measurement revolution. It goes beyond mere data analysis and focuses on the biological behaviour emerging from the dynamic interactions between system components that are organized in a hierarchical and highly connected manner. Mathematical models have been used as a conceptual framework to study such systems and their impact is maximal when there is a synergistic interplay of the models with experimental data and biological domain knowledge. The review provides an introduction to the modelling process and selectively highlights manuscripts that have strong biological impact.