bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, characterization and investigation of the thermal behaviour of six novel polynuclear cobalt and copper complexes for potential application in MOCVD
Authors: Das Mahua , Shivashankar S. A. 
Published: November 2006

AbstractNew tetranuclear complexes of copper and cobalt have been prepared under ambient conditions from corresponding metal acetates in acetone, using triethanolamine and diethanolamine as the ligands. The complexes have been characterized by infrared spectroscopy, mass spectroscopy, elemental analysis and thermal analysis. The mass spectra of the complexes show that the complexes retain the acetate moiety in their structures. Simultaneous thermogravimetric and differential thermal analysis (TGA–DTA) reveal that the complexes are solids that sublime over the temperature range 50–100 °C, under atmospheric pressure. The TGA–DTA curves reveal that the complexes retain carbon at temperatures as high as 500 °C. The presence of carbon is known to limit the mobility of growth species for oxides, restricting them to nanometersized crystals. Thus, the complexes have potential applications as precursors in the growth of nanostructured metal oxide thin films under specific CVD conditions. Because of their low sublimability, the complexes are prospective candidates as precursors for low‐temperature growth of multilayer oxide thin films where the thickness of individual layers needs to be controlled at nanometer level and for introducing dopants at low concentrations by MOCVD technique. Copyright © 2006 John Wiley & Sons, Ltd.
Immunogenetic risk and protective factors for juvenile dermatomyositis in Caucasians
Authors: Mamyrova Gulnara , O'Hanlon Terrance P. , Monroe Jason B. , Carrick Danielle Mercatante , Malley James D. , Adams Sharon , Reed Ann M. , Shamim Ejaz A. , James‐Newton Laura , Miller Frederick W. , Rider Lisa G. 
Published: November 2006

AbstractObjectiveTo define the relative importance (RI) of class II major histocompatibility complex (MHC) alleles and peptide binding motifs as risk or protective factors for juvenile dermatomyositis (DM), and to compare these with HLA associations in adult DM.MethodsDRB1 and DQA1 typing was performed in 142 Caucasian patients with juvenile DM, and the results were compared with HLA typing data from 193 patients with adult DM and 797 race‐matched controls. Random Forests classification and multiple logistic regression were used to assess the RI of the HLA associations.ResultsThe HLA–DRB1*0301 allele was a primary risk factor (odds ratio [OR] 3.9), while DQA1*0301 (OR 2.8), DQA1*0501 (OR 2.1), and homozygosity for DQA1*0501 (OR 3.2) were additional risk factors for juvenile DM. These risk factors were not present in patients with adult DM without defined autoantibodies. DQA1 alleles *0201 (OR 0.37), *0101 (OR 0.38), and *0102 (OR 0.51) were identified as novel protective factors for juvenile DM, the latter 2 also being protective factors in adult DM. The peptide binding motif DRB1 9EYSTS13 was a risk factor, and DQA1 motifs F25, S26, and 45(V/A)W(R/K)47 were protective. Random Forests classification analysis revealed that among the identified risk factors for juvenile DM, DRB1*0301 had a higher RI (100%) than DQA1*0301 (RI 57%), DQA1*0501 (RI 42%), or the peptide binding motifs. In a logistic regression model, DRB1*0301 and DQA1*0201 were the strongest risk and protective factors, respectively, for juvenile DM.ConclusionDRB1*0301 is ranked higher in RI than DQA1*0501 as a risk factor for juvenile DM. DQA1*0301 is a newly identified HLA risk factor for juvenile DM, while 3 of the DQA1 alleles studied are newly identified protective factors for juvenile DM.
Immunosuppressive medications and hospitalization for cardiovascular events in patients with rheumatoid arthritis
Authors: Solomon Daniel H. , Avorn Jerry , Katz Jeffrey N. , Weinblatt Michael E. , Setoguchi Soko , Levin Raisa , Schneeweiss Sebastian 
Published: November 2006

AbstractObjectiveThe risk of cardiovascular disease (CVD) is increased in patients with rheumatoid arthritis (RA), most likely because of increased systemic inflammation. Prior research suggests that immunosuppressive medications may reduce the risk of CVD among RA patients. This study was undertaken to investigate the effects of various immunosuppressive medications on the risk of cardiovascular events among a group of older patients with RA.MethodsIn this nested case–control study, the source cohort was derived from Medicare beneficiaries receiving a drug benefit from the state of Pennsylvania. These individuals were required to have been diagnosed as having RA on at least 2 visits and to have filled a prescription for an immunosuppressive agent. Cases were defined as those patients who were hospitalized for a cardiovascular event such as myocardial infarction or stroke, and 10 control subjects were matched to each case by age, sex, and calendar year of the index date (the time of the first cardiovascular event in each case). Current use of an immunosuppressive medication was defined as having filled a prescription for these agents within the 90 days prior to the index date. Multivariate logistic regression models that included important covariates were assessed to determine the risk of cardiovascular events associated with immunosuppressive agents and their combinations.ResultsAmong the study cohort, we identified 3,501 RA patients who fulfilled our eligibility criteria. During followup of this cohort, 946 patients were hospitalized for a cardiovascular event. Although the 95% confidence intervals (95% CIs) were wide in adjusted risk regression models with methotrexate (MTX) monotherapy as the reference group, biologic immunosuppressive agents showed neither protective nor deleterious effects (with biologics monotherapy, odds ratio [OR] 1.0, 95% CI 0.5–1.9; with biologics plus MTX combination therapy, OR 0.8, 95% CI 0.3–2.0; and with biologics plus other immunosuppressive agents, OR 1.2, 95% CI 0.7–2.2). Monotherapy with oral glucocorticoids was associated with an increased risk of cardiovascular events (OR 1.5, 95% CI 1.1 – 2.1), and a similar trend in the direction of risk was seen with glucocorticoid combination therapy (OR 1.3, 95% CI 0.8–2.0). Cytotoxic immunosuppressive agents other than MTX (azathioprine, cyclosporine, and leflunomide) were also associated with an increased risk of cardiovascular events (with both monotherapy and combination treatment, OR 1.8, 95% CI 1.1–3.0).ConclusionWhen compared with RA patients receiving MTX monotherapy, those receiving biologic immunosuppressive agents had neither an increased nor decreased risk of experiencing a cardiovascular event, whereas use of oral glucocorticoids and cytotoxic immunosuppressive agents was associated with significant increases in the risk of cardiovascular events.
Nucleus pulposus notochord cells secrete connective tissue growth factor and Up‐regulate proteoglycan expression by intervertebral disc chondrocytes
Authors: Erwin W. Mark , Ashman Keith , O'Donnel Paul , Inman Robert D. 
Published: November 2006

AbstractObjectiveTo identify the components of conditioned medium obtained from intervertebral disc nucleus pulposus–derived canine notochord cells, and to evaluate the capacity of such factors to affect disc‐derived chondrocyte gene expression of aggrecan, versican, and hyaluronic acid synthase 2 (HAS‐2) as a function of culture conditions.MethodsCanine notochord cells obtained from nonchondrodystrophic dogs were cultured within alginate beads under conditions of serum deficiency (Dulbecco's modified Eagle's medium [DMEM]) to produce notochord cell–conditioned medium (NCCM). NCCM was evaluated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and liquid chromatography–tandem mass spectroscopy. Bovine disc–derived chondrocytes were cultured with serum‐deficient medium (DMEM) and NCCM and assayed for the effect of tissue culture conditions on aggrecan, versican, and HAS‐2 gene expression. Next, chondrocyte gene expression for aggrecan was evaluated using DMEM containing recombinant connective tissue growth factor (rCTGF), and the results compared with those obtained using NCCM and DMEM.ResultsNCCM contained aggrecan, Cu/Zn superoxide dismutase, fibronectin, and CTGF precursor. Culture with NCCM caused an up‐regulation of aggrecan, versican, and HAS‐2 gene expression. NCCM induced aggrecan gene expression in chondrocytes at a level similar to that induced by 100–200 ng/ml rCTGF. Nonchondrodystrophic and chondrodystrophic canine notochord cells exhibited similar levels of CTGF gene expression.ConclusionNucleus pulposus–derived notochord cells secrete CTGF (CCN2), a recently discovered multifunctional growth factor. There is no difference between CTGF gene expression in nonchondrodystrophic and chondrodystrophic canine notochord cells, suggesting a possible role of CTGF as an anabolic factor within the disc nucleus that is, to at least some degree, dependent on the population of notochord cells within the disc nucleus.
Extreme value analysis within a parametric outlier detection framework
Authors: Cabras S. , Morales J. 
Published: November 2006

AbstractThreshold selection is a key aspect in extreme values analysis, especially when the sample size is small. The main idea underpinning this work is that extreme observations are assumed to be outliers of a specified parametric model. We propose a threshold selection method based on outlier detection using a suitable measure of surprise. Copyright © 2006 John Wiley & Sons, Ltd.
A versatile esterase from Bacillus subtilis: Cloning, expression, characterization, and its application in biocatalysis
Authors: Schmidt Marlen , Henke Erik , Heinze Birgit , Kourist Robert , Hidalgo Aurelio , Bornscheuer Uwe T. 
Published: November 2006

AbstractAn esterase from Bacillus subtilis DSM402 (BS2) was cloned and functionally expressed in E. coli. The enzyme is active up to 50°C, and the Vmax (1449 mM/min) and KM values (119 mM) were determined using p‐nitrophenyl acetate as substrate. BS2 belongs to the few hydrolases that can act on tertiary alcohols and was therefore used to resolve racemic acetates of selected tertiary alcohols, but also to selectively remove the tert‐butyl ester protecting group from peptides. In addition, the enzyme shows promiscuous amidase activity.
Effect of indole‐3‐acetic acid administration by gavage and by subcutaneous injection on rat leukocytes
Authors: Pugine Silvana M. P. , Brito Poliana de P. , Alba‐Loureiro Tatiane C. , Costa Ernane J. X. , Curi Rui , De Melo Mariza P. 
Published: November 2006

AbstractThis study was done to investigate the effect of indole‐3‐acetic acid (IAA) administered subcutaneously and by gavage on neutrophil function and cytotoxicity in neutrophils and lymphocytes. A gavage administration resulted in an increase in phagocytic capacity in neutrophils in a dose depended manner for 1 mg, 2 mg, 18 mg, and 40 mg of IAA per kg of body mass, respectively, compared with the control. Similarly, subcutaneous administration of IAA at 2, 18, and 40 mg per kg of body mass promoted a significant rise in phagocytosis by neutrophils. H2O2 production in neutrophils from treated rats by gavage was similar to those receiving subcutaneous IAA treatment, and did not show a significant difference between treatments and control. IAA treatment, whether by gavage or subcutaneous, did not produce an alteration in antioxidant enzyme activities or in glucose‐6‐phosphate dehydrogenase activity of either neutrophils or lymph nodes. Subcutaneous IAA administration did not alter the neutrophil and lymphocyte death as deduced by unaltered membrane integrity, DNA fragmentation and mitochondrial transmembrane potential, compared with controls. In conclusion, IAA administration either subcutaneously or by gavage could increase the phagocytic capacity by neutrophils and this acid administration did not have prooxidant effects or cytotoxic effects on neutrophils and lymphocytes. Copyright © 2006 John Wiley & Sons, Ltd.
Selective Labeling of Proteins by Using Protein Farnesyltransferase
Authors: Duckworth Benjamin P. , Zhang Zhiyuan , Hosokawa Ayako , Distefano Mark D. 
Published: November 2006

AbstractThe challenging task of identifying and studying protein function has been greatly aided by labeling proteins with reporter groups. Here, we present a strategy that utilizes an enzyme that labels a four‐residue sequence appended onto the C terminus of a protein, with an alkyne‐containing substrate. By using a bio‐orthogonal cycloaddition reaction, a fluorophore that carried an azide moiety was then covalently coupled to the alkyne appended on the protein. FRET was used to calculate a Förster (R) distance of 40 Å between the eGFP chromophore and the newly appended Texas Red fluorophore. This experimental value is in good agreement with the predicted R value determined by using molecular modeling. The small recognition tag, the high specificity of the enzyme, and the orthogonal nature of the derivatization reaction will make this approach highly useful in protein chemistry.
Rh‐Catalyzed Enantioselective Conjugate Addition of Arylboronic Acids with a Dynamic Library of Chiral tropos Phosphorus Ligands
Authors: Monti Chiara , Gennari Cesare , Piarulli Umberto 
Published: November 2006

AbstractA library of 19 chiral tropos phosphorus ligands, based on a free‐to‐rotate (tropos) biphenol unit and a chiral P‐bonded alcohol (11 phosphites, 1‐P(O)2O to 11‐P(O)2O) or secondary amine (8 phosphoramidites, 12‐P(O)2N to 19‐P(O)2N), were screened, individually and in combinations of two, in the rhodium‐catalyzed asymmetric conjugate addition of arylboronic acids to enones and enoates. High enantioselectivities (up to 99 % ee) and excellent yields were obtained in the addition to either cyclic or acyclic substrates. The flexible biphenolic P ligands outperformed the analogous rigid binaphtholic P ligands. Variable‐temperature 31P NMR studies revealed that the biphenolic ligands are tropos even at low temperature. Only below 190 K was a coalescence observed; upon further cooling, two atropisomers were detected. The Rh homocomplexes ([Rh(La)2]+) were also studied: in general, a single doublet (P–Rh coupling) was observed in the case of the biphenolic phosphite ligands, over the temperature range 380–230 K, demonstrating their tropos nature in the rhodium complexes even at low temperatures. On the other hand, the phosphoramidites showed different behaviors depending on the structure of the ligand and on the nature of the rhodium source. The spectrum at 230 K of the mixture of [Rh(acac)(eth)2] (eth=C2H4) with phosphite 6‐P(O)2O and phosphoramidite 19‐P(O)2N (the most enantioselective ligand combination in the conjugate addition reaction) revealed the presence of four homocomplexes (total approximately 40 %: [Rh{6‐P(O)2O}2], [Rh{(aR)‐19‐P(O)2N}2], [Rh{(aS)‐19‐P(O)2N}2], [Rh{(aR)‐19‐P(O)2N}{(aS)‐19‐P(O)2N}]) and one heterocomplex, [Rh{6‐P(O)2O}{(aR)‐19‐P(O)2N}] (approximately 60 %) In the heterocomplex, the biphenol‐derived phosphite is free to rotate (tropos) while the biphenol‐derived phosphoramidite shows a temperature‐dependent tropos/atropos behavior (coalescence temperature=310 K).
One‐Electron versus Two‐Electron Mechanisms in the Oxidative Addition Reactions of Chloroalkanes to Amido‐Bridged Rhodium Complexes
Authors: Tejel Cristina , Ciriano Miguel A. , López José A. , Jiménez Sonia , Bordonaba Marta , Oro Luis A. 
Published: November 2006

AbstractThe compound syn‐[{Rh(μ‐NH{p‐tolyl})(CNtBu)2}2] (1) oxidatively adds CCl bonds of alkyl chlorides (RCl) and dichloromethane to each metal centre to give the cationic complexes syn‐[{Rh(μ‐NH{p‐tolyl})(η1‐R)(CNtBu)2}2(μ‐Cl)]Cl and anti‐[{Rh(μ‐NH{p‐tolyl})Cl(CNtBu)2}2(μ‐CH2)]. Reaction of 1 with the chiral alkyl chloride (−)‐(S)‐ClCH(Me)CO2Me (R*Cl) gave [{Rh(μ‐NH{p‐tolyl})(η1‐R*)(CNtBu)2}2(μ‐Cl)]Cl ([3]Cl) as an equimolecular mixture of the meso form (R,S)‐[3]Cl‐Cs and one enantiomer of the chiral form [3]Cl‐C2. This reaction, which takes place in two steps, was modeled step‐by‐step by reacting the mixed‐ligand complex syn‐[(cod)Rh(μ‐NH{p‐tolyl})2Rh(CNtBu)2] (4) with R*Cl, as a replica of the first step, to give [(cod)Rh(μ‐NH{p‐tolyl})2RhCl(η1‐R*)(CNtBu)2] (5) with racemization of the chiral carbon. Further treatment of 5 with CNtBu to give the intermediate [(CNtBu)2Rh(μ‐NH{p‐tolyl})2RhCl(η1‐R*)(CNtBu)2], followed by reaction with R*Cl reproduced the regioselectivity of the second step to give (R,S)‐[3]Cl‐Cs and [3]Cl‐C2 in a 1:1 molar ratio. Support for an SN2 type of reaction with inversion of the configuration in the second step was obtained from a similar sequence of reactions of 4 with ClCH2CO2Me first, then with CNtBu, and finally with R*Cl to give [(CNtBu)2(η1‐CH2R)Rh(μ‐NH{p‐tolyl})2(μ‐Cl)Rh(η1‐R*)(CNtBu)2]Cl (R = CO2Me, [7]Cl) as a single enantiomer with the R configuration at the chiral carbon. The reactions of 1 with (+)‐(S)‐XCH2CH(CH3)CH2CH3 (X = Br, I) gave the related complexes [{Rh(μ‐NH{p‐tolyl})(η1‐CH2CH(CH3)CH2CH3)(CNtBu)2}2(μ‐X)]X, probably by following an SN2 profile in both steps.
One‐Step Fabrication and High Photocatalytic Activity of Porous TiO2 Hollow Aggregates by Using a Low‐Temperature Hydrothermal Method Without Templates
Authors: Liu Zhaoyang , Sun Darren D. , Guo Peng , Leckie James O. 
Published: November 2006

AbstractPorous TiO2 hollow aggregates have been synthesized on a large scale by means of a simple hydrothermal method without using any templates. The as‐prepared products were characterized by means of field emission scanning electron microscopy, XRD, TEM, nitrogen adsorption, UV/Vis diffuse reflectance spectroscopy, and FTIR spectroscopy. The photocatalytic activity of the aggregates was demonstrated through the photocatalytic degradation of Rhodamine B. Structural characterization indicates that the porous TiO2 aggregates are 500–800 nm in diameter and display mesoporous structure. The average pore sizes and BET surface areas of the aggregates are 12 nm and 168 m2 g−1, respectively. Optical adsorption investigations show that the aggregates possess an optical band‐gap energy of 3.36 eV. The as‐prepared products were substantially more effective photocatalysts than the commercially available photocatalyst P25. The dye degradation rate of the porous TiO2 hollow aggregates is more than twice that of P25. The high photoactivities of the aggregates can be attributed to the combined effects of several factors, namely, large surface areas, the existence of mesopores, and the high band‐gap energy. In addition, the as‐prepared products can be easily recycled.
Oxidation of Linear Trinuclear Ruthenium Complexes [Ru3(dpa)4Cl2] and [Ru3(dpa)4(CN)2]: Synthesis, Structures, Electrochemical and Magnetic Properties
Authors: Kuo Ching‐Kuo , Liu Isiah Po‐Chun , Yeh Chen‐Yu , Chou Chung‐Hsien , Tsao Ting‐Bin , Lee Gene‐Hsiang , Peng Shie‐Ming 
Published: November 2006

AbstractThe neutral, monocationic, and dicationic linear trinuclear ruthenium compounds [Ru3(dpa)4(CN)2], [Ru3(dpa)4(CN)2][BF4], [Ru3(dpa)4Cl2][BF4], and [Ru3(dpa)4Cl2][BF4]2 (dpa=the anion of dipyridylamine) have been synthesized and characterized by various spectroscopic techniques. Cyclic voltammetric and spectroelectrochemical studies on the neutral and oxidized compounds are reported. These compounds undergo three successive metal‐centered one‐electron‐transfer processes. X‐ray structural studies reveal a symmetrical Ru3 unit for these compounds. While the metalmetal bond lengths change only slightly, the metalaxial ligand lengths exhibit a significant decrease upon oxidation of the neutral complex. The electronic configuration of the Ru3 unit changes as the axial chloride ligands are replaced by the stronger “π‐acid” cyanide axial ligands. Magnetic measurements and 1H NMR spectra indicate that [Ru3(dpa)4Cl2] and [Ru3(dpa)4Cl2][BF4]2 are in a spin state of S=0 and [Ru3(dpa)4Cl2][BF4], [Ru3(dpa)4(CN)2], and [Ru3(dpa)4(CN)2][BF4] are in spin states of S=1/2, 1, and 3/2, respectively. These results are consistent with molecular orbital (MO) calculations.
A sufficient condition of controllability of RLCM active networks over F(z)
Authors: Lu Kai‐Sheng 
Published: November 2006

AbstractThis paper defines the separability of an RLCM active network and finds a sufficient condition that the active network is controllable and observable over F(z) if its passive network is controllable and observable over F(z). So the controllability (observability) criteria in (Proc. IEEE ISCAS, 2005) can be used to analyse and design active networks. Copyright © 2006 John Wiley & Sons, Ltd.
Reticular Nickel Microwires with Assembled Nanostructures: Synthesis, Magnetism and Catalysis for the Growth of Carbon Nanotubes
Authors: Ni Xiaomin , Zhao Qingbiao , Zhang Yongfeng , Zheng Huagui 
Published: November 2006

AbstractReticular nickel microwires assembled from different‐shaped building blocks are fabricated by a simple, one‐pot method in the absence of any surfactants or external magnetic field. The synthetic process involves the chemical reduction of a nickel complex with hydrazine under controlled reaction conditions. Our strategy focuses on the modulation of the reaction rate to control the shape of the subunits and their spontaneous assembly behavior, which avoids the need for surfactants or an external force. The nickel wires can be reproducibly created with the assistance of various complexants, such as citrate, tartrate, lactate, ethylenediamine, triethanolamine and diethanolamine, which proves the generality of this method. These nickel wires show variable magnetic properties and catalysis for the growth of carbon nanotubes in pyrolyzing acetone due to the nature of their microstructures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
I–‐Catalyzed Reaction of 5‐Methoxyoxazoles with Organic Iodides – An Efficient Synthesis of Azalactones
Authors: Lu Lianghua , Lu Ping , Ma Shengming 
Published: November 2006

AbstractAn I–‐catalyzed methoxy carbon–oxygen bond cleavage in 5‐methoxyoxazoles leading to the synthesis of azalactones, precursors of quaternary amino acids, has been developed. A series of 4‐substituted azalactones were obtained through the variation of the alkyl iodides and differently substituted 5‐methoxyoxazoles. Further study indicated that azalactone 3aa may be easily converted to benzoyl‐protected quaternary amino acid 4aa. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of a Cyclic Tetrameric Purine by Successive Cross‐Coupling Reactions and Subsequent Pd‐Catalyzed Cyclization
Authors: Guthmann Holger , Könemann Martin , Bach Thorsten 
Published: November 2006

AbstractThe tetrameric N‐benzyl‐protected purine (quaterpurine) 2 was synthesized and characterized as its palladium complex [2·Pd]. The synthesis commenced with the Pd‐catalyzed cross‐coupling of 8‐zincated 9‐benzyl‐6‐chloro‐8‐iodopurine (9) and 9‐benzyl‐6‐iodopurine (11) establishing the first C‐6/C‐8 bond. The sequence was repeated twice after iodo‐de‐chlorination at C‐6′ (C‐6″) of the respective dimer 12 and trimer 15. The final ring closure was achieved at the tetrameric 6″′‐chloro‐8‐iodoquaterpurine 3b by a reductive intramolecular cross‐coupling with hexamethylditin in the presence of Pd2(dba)3 and P(2‐furyl)3. The overall yield in the eight step sequence was 17 % starting from 9‐benzyl‐6‐chloropurine (8), the immediate precursor of 11. Other strategies to combine the purine fragments, i.e. by dimer/dimer bond formation or by regioselective cross‐coupling, were not successful. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)