bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Single‐Source‐Precursor Approach to Late Transition Metal Molybdate Materials: The Structural Role of Chelating Ligands in the Formation of Heterometallic Heteroleptic Alkoxide Complexes
Authors: Werndrup Pia , Seisenbaeva Gulaim A. , Westin Gunnar , Persson Ingmar , Kessler Vadim G. 
Published: February 2006

AbstractThe synthesis and structural determination of three new heterometallic molybdenum complexes, one with cobalt and two with nickel and two of these with β‐diketonate ligands and one with amino alcohol ligands, are presented. The reaction of cobalt acetylacetonate with [MoO(OMe)4] provides [Co2Mo2O2(acac)2(OMe)10] (1) and [MoO(acac)(OMe)3] (4),and the reaction of nickel acetylacetonate with [MoO(OMe)4]provides [Ni2Mo2O2(acac)2(OMe)10] (2) and 4. The reaction of [Ni(ORN)2] (RN = CHMeCH2NMe2) with [MoO(OMe)4] yields [Ni2Mo2O2(ORN)2(OMe)10] (3). The two new oxomolybdenum complexes undergo ether elimination upon storage to give the corresponding dioxo complexes [MoO2(acac)(OMe)]2 (5) and [MoO2(ORN)(OMe)]2 (6). Compounds 3 and 4 could also be obtained from the reaction of stoichiometric amounts of Hacac with [MoO(OMe)4] and [MoO2(OMe)2], respectively. The local structure around the nickel atom in compound 2 in solution and compound 3 in the solid state and in toluene/hexane solution has been determined by means of EXAFS spectroscopy. The complexes are intended to be used as single‐source precursors, which are attractive in coatings and for the preparation of mesoporous materials; its application for the synthesis of nickel molybdate by sol–gel processing is therefore reported. The oxide material obtained from 3 displays a uniform grain size and a large surface area. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
The Role of Anions in Addressing the Outcome of the Reaction of Tetramethylthiourea with cis‐PtII(phos)2 Moieties (phos = PPh3 or ${1 \over 2}$dppe), Cyclometallation vs. Hydrolysis to Monothiocarbamato, and the Crystal Structure of trans‐Bis(N‐dimethylmonothiocarbamato)bis(triphenylphosphane)platinum(II)
Authors: Alesi Maria , Fantasia Serena , Manassero Mario , Pasini Alessandro 
Published: February 2006

AbstractThe product of the reaction between tetramethylthiourea (tmtu) and cis‐PtII(phos)2 moieties (phos = PPh3, or ${1 \over 2}$ dppe)depends on the anionic species present. With NO3–, CF3CO2–,CF3SO3– and BF4–, the cyclometallate cationic complex [Pt(phos)2(tmtu*‐C,S)]+ is obtained (tmtu* is tmtu deprotonated at one methyl group). The acetato and malonato complexes are inactive towards such deprotonation, but, in the presence of water, promote tmtu hydrolysis with formation of N‐dimethylmonothiocarbamato (mtc) complexes in which mtc is S‐coordinated. cis‐[Pt(PPh3)2(mtc)2] isomerises slowly to the trans isomer, whose crystal structure is reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Nebularic Acids and Nebularilactones, Novel Drimane Sesquiterpenoids from the Fungus Lepista nebularis
Authors: Kemami Wangun Hilaire V. , Dörfelt Heinrich , Hertweck Christian 
Published: February 2006

AbstractFour (nor‐)drimane sesquiterpenoids, nebularic acids A (1) and B (2) and nebularilactones A (3) and B (4), were isolated from a cultured Lepista nebularis strain by bioassay‐guided chromatography, and their structures were elucidated by mass spectrometry and NMR spectroscopy. Nebularic acid A (1) and in particular nebularic acid B (2), which features an α,β‐epoxy carboxylate moiety, show antifungal and antibacterial activities. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis of Ecteinascidin 743 Analogues from Cyanosafracin B: Isolation of a Kinetically Stable Quinoneimine Tautomer of a 5‐Hydroxyindole
Authors: Ceballos Plácido A. , Pérez Marta , Cuevas Carmen , Francesch Andrés , Manzanares Ignacio , Echavarren Antonio M. 
Published: February 2006

AbstractPhthalimido derivatives of cyanosafracin B have been synthesized as analogues of the antitumor agent ecteinascidin 743. As part of this study, a quinoneimine has been prepared, which is a kinetically stable tautomer of a 5‐hydroxyindole. This quinoneimine tautomer is stable under acidic and mild basic conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Vapor‐Surface Sol‐Gel Deposition of Titania Alternated with Protein Adsorption for Assembly of Electroactive, Enzyme‐Active Films
Authors: Lu Haiyun , Yang Jing , Rusling James F. , Hu Naifei 
Published: February 2006

AbstractCombining vapor‐surface sol‐gel deposition of titania with alternate adsorption of oppositely charged iron heme proteins provided ultrathin {TiO2/protein}n films with reversible voltammetry extended to 15 TiO2/protein bilayers, more than twice that of more conventional polyion‐protein or nanoparticle‐protein films made by alternate layer‐by‐layer adsorption. Catalytic activity toward O2, H2O2, and NO$\rm{ {_{2}^{-}}}$ was also improved significantly compared to the conventionally fabricated films. The method involves vaporization of titanium butoxide into thin films of water, forming porous TiO2 sol‐gel layers. Myoglobin (Mb), hemoglobin (Hb), and horseradish peroxidase (HRP) were assembled by adsorption alternated with the vapor‐deposited TiO2 layers. Improved electrochemical and catalytic performance may be related to better film permeability leading to better mass transport within the films, as suggested by studies with soluble voltammetric probes, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The electrochemical and electrocatalytic activity of the films can be controlled by tailoring the amount of water with which the metal alkoxide precursor vapor reacts and the number of bilayers deposited in the assembly.
Monolithic silica capillary column with coated cellulose tris(3,5‐dimethylphenylcarbamate) for capillary electrochromatographic separation of enantiomers
Authors: Qin Feng , Xie Chuanhui , Feng Shun , Ou Junjie , Kong Liang , Ye Mingliang , Zou Hanfa 
Published: February 2006

AbstractMonolithic silica capillary columns were prepared by a sol‐gel process in fused‐silica capillaries with an inner diameter of 50 μm and were modified by coating of cellulose tris(3,5‐dimethylphenylcarbamate). Influences of the factors in the modification process on enantiomer separations were investigated. The prepared columns were used to perform enantiomer separations by CEC. Fifteen and two pairs of enantiomers were separated under aqueous and nonaqueous mobile phases, respectively, and most of them were baseline‐separated with very high column efficiencies. The Van Deemter curve was found flat under high linear velocity of the mobile phase, which indicated favorable kinetic properties of the prepared columns. Baseline separation of a pair of enantiomers was achieved in 90 s with high‐column efficiency by short‐end separation under high voltage.
Determination of acid–base dissociation constants of amino‐ and guanidinopurine nucleotide analogs and related compounds by capillary zone electrophoresis
Authors: Šolínová Veronika , Kašička Václav , Koval Dušan , Česnek Michal , Holý Antonín 
Published: February 2006

AbstractCZE has been applied for determination of acid–base dissociation constants (pKa) of ionogenic groups of newly synthesized amino‐ and (amino)guanidinopurine nucleotide analogs, such as acyclic nucleoside phosphonate, acyclic nucleoside phosphonate diesters and other related compounds. These compounds bear characteristic pharmacophores contained in various important biologically active substances, such as cytostatics and antivirals. The pKa values of ionogenic groups of the above compounds were determined by nonlinear regression analysis of the experimentally measured pH dependence of their effective electrophoretic mobilities. The effective mobilities were measured by CZE performed in series of BGEs in a broad pH range (3.50–11.25), at constant ionic strength (25 mM) and temperature (25°C). pKa values were determined for the protonated guanidinyl group in (amino)guanidino 9‐alkylpurines and in (amino)guanidinopurine nucleotide analogs, such as acyclic nucleoside phosphonates and acyclic nucleoside phosphonate diesters, for phosphonic acid to the second dissociation degree (—2) in acyclic nucleoside phosphonates of amino and (amino)guanidino 9‐alkylpurines, and for protonated nitrogen in position 1 (N1) of purine moiety in acyclic nucleoside phosphonates of amino 9‐alkylpurines. Thermodynamic pKa of protonated guanidinyl group was estimated to be in the range of 7.75–10.32, pKa of phosphonic acid to the second dissociation degree achieved values of 6.64–7.46, and pKa of protonated nitrogen in position 1 of purine was in the range of 4.13–4.89, depending on the structure of the analyzed compounds.
Radiation‐induced DNA damage and repair in peripheral blood mononuclear cells from Nijmegen breakage syndrome patients and carriers assessed by the Comet assay
Authors: Bürger Susann , Schindler Detlev , Fehn Martin , Mühl Bettina , Mahrhofer Hartmut , Flentje Michael , Hoehn Holger , Seemanová Eva , Djuzenova Cholpon S. 
Published: February 2006

AbstractNijmegen breakage syndrome (NBS) patients and carriers are predisposed to malignancy and are often treated with X‐irradiation. In the present study, the single‐cell gel electrophoresis (Comet) assay was used to examine radiation‐induced DNA damage and repair in peripheral blood mononuclear cells from NBS patients (n = 13) and carriers (n = 36) of six unrelated families. Cells from apparently healthy donors (n = 10) and from breast cancer patients with normal clinical radiosensitivity (n = 10) served as controls. Cells were irradiated with 5 Gy of X‐rays and assayed for initial DNA damage and for residual DNA damage after 40 min of repair; the kinetics of DNA repair also was estimated. In addition, the nuclear area of unirradiated cells was extracted from the Comet data. The initial radiation‐induced DNA fragmentation indicated that cells from members of two out of six NBS families were significantly more sensitive to X‐irradiation than cells from the controls. Cells from four NBS families had longer DNA repair half‐time values, while cells from five NBS families had significantly increased residual DNA damage following repair. The mean nuclear area of unirradiated cells processed in the Comet assay was 1.3‐fold higher in cells from all NBS families than in the controls (P < 0.05). Notably, the Comet assay parameters (initial and residual DNA damage and the repair kinetics) of irradiated NBS cells predicted the carrier status of the majority (86%) of blindly tested individuals. The prediction of NBS status was higher if the nuclear area of unirradiated cells was used as the endpoint. The results of this study suggest that the impaired radiation response of NBS cells should be taken into account if radiotherapy of NBS patients and carriers is required. Environ. Mol. Mutagen, 2006. © 2006 Wiley‐Liss, Inc.
DNA damage in bone marrow and blood cells of mice exposed to municipal sludge leachates
Authors: Tewari Anamika , Dhawan Alok , Gupta Shrawan Kumar 
Published: February 2006

AbstractLeachates of municipal solid waste from unsecured disposal sites contaminate sources of potable water and affect human health. In the present study, we have used the Comet assay to evaluate the DNA damage in mice exposed to municipal sludge leachates. Ten percent leachates were prepared from municipal sludge obtained from two different disposal drains. Male Swiss albino mice were treated daily with 0.1–0.4 ml of the leachates by oral gavage for 15 days, and the DNA damage was evaluated in bone marrow and blood using Olive tail moment, % tail DNA, and tail length as measures of DNA damage. Physicochemical and metal analysis of the leachates detected the presence of cadmium, chromium, copper, nickel, lead, and zinc, as well as elevated concentrations of sulfate and nitrate. Both of the leachates produced significant dose‐responsive increases in DNA damage in both mouse tissues. There were no significant differences in the responses for any of the Comet endpoints between tissues (for the same leachate sample) or between leachate samples (for the same tissue). The results of this study indicate that municipal waste leachates produce DNA damage in vivo. Environ. Mol. Mutagen. 2006. © 2006 Wiley‐Liss, Inc.
Haplotype association analysis for late onset diseases using nuclear family data
Authors: Li Chun , Boehnke Michael 
Published: February 2006

AbstractIn haplotype‐based association studies for late onset diseases, one attractive design is to use available unaffected spouses as controls (Valle et al. [1998] Diab. Care 21:949–958). Given cases and spouses only, the standard expectation‐maximization (EM) algorithm (Dempster et al. [1977] J. R. Stat. Soc. B 39:1–38) for case‐control data can be used to estimate haplotype frequencies. But often we will have offspring for at least some of the spouse pairs, and offspring genotypes provide additional information about the haplotypes of the parents. Existing methods may either ignore the offspring information, or reconstruct haplotypes for the subjects using offspring information and discard data from those whose haplotypes cannot be reconstructed with high confidence. Neither of these approaches is efficient, and the latter approach may also be biased. For case‐control data with some subjects forming spouse pairs and offspring genotypes available for some spouse pairs or individuals, we propose a unified, likelihood‐based method of haplotype inference. The method makes use of available offspring genotype information to apportion ambiguous haplotypes for the subjects. For subjects without offspring genotype information, haplotypes are apportioned as in the standard EM algorithm for case‐control data. Our method enables efficient haplotype frequency estimation using an EM algorithm and supports probabilistic haplotype reconstruction with the probability calculated based on the whole sample. We describe likelihood ratio and permutation tests to test for disease‐haplotype association, and describe three test statistics that are potentially useful for detecting such an association. Genet. Epidemiol. 2006. © 2006 Wiley‐Liss, Inc.
Self‐reported health: reliability and consequences for health inequality measurement
Authors: Clarke Philip M. , Ryan Chris 
Published: February 2006

AbstractSelf‐reported health (SRH) is one of the most frequently employed measures for assessing income‐related health inequalities between counties. A previous study has shown that 28% of respondents changed their assessment of their health status when asked a SRH question on two occasions in the same survey (first as part of self‐completed questionnaire and then in a personal interview). This study re‐examines this issue using another survey where SRH was again asked twice of respondents, but this time the personal interview was first and self‐completion second. We find the same variation in responses, but the predominant direction is away from the ‘extreme’ categories ‘Excellent’ and ‘Poor’ which is the opposite direction to the previous study. We therefore conclude that the most likely explanation is a mode of administration effect that makes people less likely to choose the extreme categories in a self‐completion questionnaire, but not a personal interview. However, this effect has a relatively minor impact on measures of inequality. This is due to a large proportion of the movement (i.e. movement to the middle) not being related to income and hence does not systematically impact on the cumulative distribution of health across this measure of socio‐economic status. Copyright © 2006 John Wiley & Sons, Ltd.
Who does the hat fit? Teenager heterogeneity and the effectiveness of information policies in preventing cannabis use and heavy drinking
Authors: Etilé Fabrice 
Published: February 2006

AbstractThis paper models heterogeneity in the relationship between exposure to information at school or in the media and cannabis use and heavy drinking, using latent class techniques applied to data on French teenagers collected in 1993. Teenagers cluster in five classes which differ in their tastes for drunkenness and cannabis, and in the correlations between information exposure and cannabis use or heavy drinking. Teenager heterogeneity and habit‐formation or precociousness effects limit the effectiveness of general information policies. Improving the impact of prevention requires that interventions be better targeted and personalised. We show how economic theory, latent class techniques and existing psychometric questionnaires can be used to build simple statistical tools for targeting prevention policies. Copyright © 2006 John Wiley & Sons, Ltd.
Vascular perfusion of human lung cancer in a rat orthotopic model using dynamic contrast‐enhanced magnetic resonance imaging
Authors: Rosen Yael , Ramniceanu Gregory , Margalit Raanan , Grobgeld Dov , Eilam Raya , Degani Hadassa , Furman‐Haran Edna 
Published: February 2006

AbstractLung cancer is the leading cause of death among cancers. Early detection and diagnosis present a major goal in the efforts to improve survival rates of lung cancer patients. Changes in angiogenic activity and microvascular perfusion properties in cancers can serve as markers of malignancy. The aim of this study was to employ MRI means to measure the microvascular perfusion parameters of orthotopic nonsmall cell lung cancer, using the experimental rat model. Anatomical and dynamic contrast‐enhanced lung images were acquired at high spatial resolution, and registered and analyzed, pixel by pixel and globally, by means of a model‐based algorithm. The MRI output yielded color‐coded parametric images of the influx and efflux transcapillary transfer constants that indicated rapid microvascular perfusion. The transfer constants were about 1 order of magnitude higher than those found in other tumors or in nonorthotopic lung cancer, with the influx constant median value of 0.42 min−1 and the efflux constant median value of 1.61 min−1. The rapid perfusion was in accord with the immunostaining of the capillaries, which suggested the tumor exploitation of the existing alveolar vessels. The results showed that high resolution, dynamic, contrast‐enhanced MRI is an effective tool for the quantitative measurement of spatial and temporal changes in lung cancer perfusion and vasculature. © 2006 Wiley‐Liss, Inc.
TGF‐β1 immobilized tri‐co‐polymer for articular cartilage tissue engineering
Authors: Chou Cheng‐Hung , Cheng Winston T. K. , Lin Chien‐Cheng , Chang Chih‐Hung , Tsai Chien‐Chen , Lin Feng‐Huei 
Published: February 2006

AbstractTri‐co‐polymer with composition of gelatin, hyaluronic acid and chondroitin‐6‐sulfate has been used to mimic the cartilage extracellular matrix as scaffold for cartilage tissue engineering. In this study, we try to immobilize TGF‐β1 onto the surface of the tri‐co‐polymer sponge to suppress the undesired differentiation during the cartilage growth in vitro. The scaffold was synthesized with a pore size in a range of 300–500 μm. TGF‐β1 was immobilized on the surface of the tri‐co‐polymer scaffold with 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimid (EDC) as a crosslinking agent. Tri‐co‐polymer scaffolds with and without TGF‐β1 were seeded with porcine chondrocytes and cultured in a spinner flask for 2, 4, and 6 weeks. The chondrocytes were characterized by the methods of immunohistochemical staining with anti‐type II collagen and anti‐S‐100 protein monoclonal antibody, and RT‐PCR. After culturing for 4 weeks, chondrocytes showed positive in S‐100 protein, Alcian blue, and type II collagen for the scaffold with TGF‐β1 immobilization. There is no observed type I and type X collagen expression in the scaffolds from the observation of RT‐PCR. In addition, the scaffold without TGF‐β1 immobilization, type X collagen, can be detected after cultured for 2 weeks. Type I collagen was progressively expressed after 4 weeks. These results can conclude that TGF‐β1 immobilized scaffold can suppress chondrocytes toward prehypertrophic chondrocytes and osteolineage cells. The tri‐co‐polymer sponge with TGF‐β1 immobilization should have a great potential in cartilage tissue engineering in the future. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Three‐dimensional printing of porous polyethylene structure using water‐based binders
Authors: Suwanprateeb J. , Chumnanklang R. 
Published: February 2006

AbstractThis study demonstrated a freeform fabrication of porous hydrophobic polyethylene parts by three‐dimensional printing technique, using water‐based binder. This involved initially making a green structure by printing a binder onto the mixture of polyethylene and water soluble adhesive powder bed. The green structure was thermal treated to melt polyethylene fraction to achieve a well‐connected structure within the part. Adhesive components were then leached out in water, leaving only porous structure of polyethylene. Specimens with ratios of polyethylene to adhesive from 80:20 to 20:80 were fabricated and characterized. It was found that increasing polyethylene content increased density, modulus, and strength while decreased porosity. Preliminary in vitro toxicity test of porous parts using L929 cells showed that the cells that were in contact with samples were healthy. No inhibition zone was observed. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Relationship between fracture toughness and flexural strength in dental porcelains
Authors: Cesar Paulo Francisco , Yoshimura Humberto Naoyuki , Miranda Walter Gomes , Miyazaki Caroline Lumi , Muta Luciana Mayumi , Filho Leondardo Eloy Rodrigues 
Published: February 2006

AbstractThe aim of this study was to investigate the correlation between fracture toughness (KIc) and flexural strength (FS) in dental porcelains. Porcelains with different leucite contents and clinical indications were used (A, B, C, D, and E). KIc was determined by surface crack in flexure method (SCF) and FS was determined by four‐point‐bending test. Microstructural characterization was also carried out. The leucite contents of porcelains A, B, C, D, and E were, respectively, 22, 22, 6, 15, and 0%. Materials with higher leucite content (A and B) presented significantly higher KIc values compared to materials with lower leucite content (C and E). The Weibull moduli (m) of porcelains A and B were statistically higher than those of the other three materials. Regarding characteristic strength (σ0), porcelains D and E showed similar values and statistically higher than those of the other materials which were statistically different from each other. According to the regression analysis, σ0 increased with the increase of KIc until ∼0.75 MPa m1/2. After that, the increase in KIc was accompanied by a decrease in σ0. However, the Weibull modulus increased with the increase in KIc, especially for values greater than 0.80 MPa m1/2. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006