bluuebunny/crossref_metadata_2025_split huggingface dataset:
Examination of the Causes of Covariation Between Conduct Disorder Symptoms and Vulnerability to Drug Dependence
Authors: Button Tanya M. M. , Hewitt John K. , Rhee Soo Hyun , Young Susan E. , Corley Robin P. , Stallings Michael C. 
Published: May 2006

AbstractConduct disorder (CD) symptoms and substance dependence commonly co-occur. Both phenotypes are highly heritable and a common genetic influence on the covariation has been suggested. The aim of this study was to determine the extent to which genes and environment contribute to the covariance between CD and drug dependence using twins from the Colorado Longitudinal Twin Sample and the Colorado Twin Registry. A total of 880 twin pairs (237 monozygotic [MZ] female, 195 MZ male, 116 dizygotic [DZ] female, 118 DZ male and 214 DZ opposite-sex) aged 13 to 18 (mean = 15.65) were included in the analysis. CD was assessed by lifetimeDiagnostic and Statistical Manual of Mental Disorders(4th ed.; DSM-IV; American Psychiatric Association, 1994) symptom count and a polysubstance dependence vulnerability index was developed from responses to the Composite International Diagnostic Interview — Substance Abuse Module. A bivariate Cholesky Decomposition model was used to partition the cause of variation and covariation of the two phenotypes. No sex-limitation was observed in our data, and male and female parameter estimates were constrained to be equal. Both CD symptoms and dependence vulnerability were significantly heritable, and genes, shared environment and nonshared environment all contributed to the covariation between them. Genes contributed 35% of the phenotypic covariance, shared environment contributed 46%, and nonshared environmental influences contributed the remaining 19% to the phenotypic covariance. Therefore, there appears to be pleiotropic genetic influence on CD symptoms and dependence vulnerability.
False Disease Region Identification From Identity-By-Descent Haplotype Sharing in the Presence of Phenocopies
Authors: Macgregor Stuart , Knott Sara A. , Visscher Peter M. 
Published: May 2006

AbstractLinkage analysis (either parametric or nonparametric) is commonly applied to identify chromosomal regions using related individuals affected by disease. In complex disease the incomplete relationship between phenotype and genotype can be modeled using a phenocopy parameter, the probability that an individual is affected given they do not carry the disease mutation of interest, and a nonpenetrance parameter, the probability that an individual is not affected given they do carry the disease mutation of interest. If the linkage phase between multiple markers and a putative disease locus is known, then haplotypes carrying the mutation can, in principle, be identified by comparing the chromosome segments that are shared identical-by-descent (IBD) across affected individuals. We consider here the effect of a nonzero phenocopy rate on the linkage peak and hence upon the identification of disease haplotypes that are shared IBD between affected individuals. We show, by theory and computer simulation, that in diseases for which there is a nonzero phenocopy rate, the chromosomal regions identified may not include the true disease locus. We utilize a LOD-1 confidence interval for a widely used nonparametric linkage statistic. We find that in small/moderate samples this confidence interval may be inappropriate. We give specific examples where the phenocopy rates are nonnegligible in some complex diseases. The success of further work to identify the causal mutations underlying the linkage peaks in these diseases will depend on researchers allowing for the presence of phenocopies by examining appropriately wide regions around the initial positive linkage finding.
A genome‐wide screen for nicotine dependence susceptibility loci
Authors: Swan Gary E. , Hops Hyman , Wilhelmsen Kirk C. , Lessov‐Schlaggar Christina N. , Cheng Li S.‐C. , Hudmon Karen S. , Amos Christopher I. , Feiler Heidi S. , Ring Huijun Z. , Andrews Judy A. , Tildesley Elizabeth , Benowitz Neal 
Published: May 2006

AbstractGenome‐wide model free linkage analysis was conducted for nicotine dependence and tobacco use phenotypes in 607 members of 158 nuclear families consisting of at least two ever smokers (100 or more cigarettes smoked in lifetime). DNA from whole blood was genotyped for 739 autosomal microsatellite polymorphisms with an average inter‐marker distance of 4.6 cM. A peak LOD score of 2.7 was observed on chromosome 6 for scores for the Fagerström Test for Nicotine Dependence. Exploratory analyses were conducted to determine whether sequence variation at other loci affected other measures of dependence or tobacco use. Four additional loci with LOD scores of 2.7 or more were associated with alternative measures of nicotine dependence, one with current frequency of use, and one with smoking cessation. Several of the corresponding support intervals were near putative loci reported previously (on chromosomes 6, 7, and 8) while others appear to be novel (on chromosomes 5, 16, and 19). © 2006 Wiley‐Liss, Inc.
Directed evolution of an industrial biocatalyst: 2‐deoxy‐D‐ribose 5‐phosphate aldolase
Authors: Jennewein Stefan , Schürmann Martin , Wolberg Michael , Hilker Iris , Luiten Ruud , Wubbolts Marcel , Mink Daniel 
Published: May 2006

AbstractAldolases are emerging as powerful and cost efficient tools for the industrial synthesis of chiral molecules. They catalyze enantioselective carbon‐carbon bond formations, generating up to two chiral centers under mild reaction conditions. Despite their versatility, narrow substrate ranges and enzyme inactivation under synthesis conditions represented major obstacles for large‐scale applications of aldolases. In this study we applied directed evolution to optimize Escherichia coli 2‐deoxy‐D‐ribose 5‐phosphate aldolase (DERA) as biocatalyst for the industrial synthesis of (3R,5S)‐6‐chloro‐2,4,6‐trideoxyhexapyranoside. This versatile chiral precursor for vastatin drugs like Lipitor (atorvastatin) is synthesized by DERA in a tandem‐aldol reaction from chloroacetaldehyde and two acetaldehyde equivalents. However, E. coli DERA shows low affinity to chloroacetaldehyde and is rapidly inactivated at aldehyde concentrations useful for biocatalysis. Using high‐throughput screenings for chloroacetaldehyde resistance and for higher productivity, several improved variants have been identified. By combination of the most beneficial mutations we obtained a tenfold improved variant compared to wild‐type DERA with regard to (3R,5S)‐6‐chloro‐2,4,6‐trideoxyhexapyranoside synthesis, under industrially relevant conditions.
Influence of water‐miscible organic solvents on kinetics and enantioselectivity of the (R,‐specific alcohol dehydrogenase from Lactobacillus brevis
Authors: Schumacher Jan , Eckstein Marrit , Kragl Udo 
Published: May 2006

AbstractUsing the organic solvents acetonitrile and 1,4‐dioxane as water‐miscible additives for the alcohol dehydrogenase (ADH)‐catalyzed reduction of butan‐2‐one, we investigated the influence of the solvents on enzyme reaction behavior and enantioselectivity. The NADP+‐dependent (R,‐selective ADH from Lactobacillus brevis (ADH‐LB) was chosen as biocatalyst. For cofactor regeneration, the substrate‐coupled approach using propan‐2‐ol as co‐substrate was applied. Acetonitrile and 1,4‐dioxane were tested from mole fraction 0.015 up to 0.1. Initial rate experiments revealed a complex kinetic behavior with enzyme activation caused by the substrate butan‐2‐one, and increasing KM values with increasing solvent concentration. Furthermore, these experiments showed an enhancement of the enantioselectivity for (R,‐butan‐2‐ol from 37% enantiomeric excess (ee) in pure phosphate buffer up to 43% ee in the presence of 0.1 mol fraction acetonitrile. Finally, the influence of the co‐solvents on water activity of the reaction mixture and on enzyme stability was investigated.
Involvement of protein kinase B and mitogen-activated protein kinases in experimental normothermic liver ischaemia–reperfusion injury
Authors: Cursio R , Filippa N , Miele C , Van Obberghen E , Gugenheim J 
Published: May 2006

Abstract

Background
This study evaluated the role of protein kinase B (PKB), phosphatidylinositol 3-kinase (PI3-K), Bcl-2-associated death protein (BAD) and mitogen-activated protein kinases (MAPKs) in normothermic ischaemia–reperfusion (IR)-induced apoptosis in rat liver.

Methods
Rats were divided into two groups that received either phosphate-buffered saline (control) or the caspase inhibitor Z-Asp-2,6-dichorobenzoyloxymethylketone (Z-Asp-cmk), injected intravenously 2 min before the induction of 120 min of normothermic liver ischaemia. Liver apoptosis was assessed by the terminal deoxyribonucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) method. PI3-K, PKB, BAD and MAPK activities were measured in ischaemic and non-ischaemic lobes at various times after reperfusion.

Results
The number of TUNEL-positive cells was significantly decreased after pretreatment with Z-Asp-cmk. In controls, PI3-K and PKB activities and BAD phosphorylation were inhibited in ischaemic liver lobes. The MAPKs (extracellular signal-regulated kinases, c-Jun N-terminal kinase and p38) showed different patterns of activation during IR. PKB activity was not modified by pretreatment with Z-Asp-cmk.

Conclusion
Induction of apoptosis during IR liver injury might be triggered by inactivation of the antiapoptotic PI3-K–PKB pathway and activation of the proapoptotic MAPKs.
Surgeon experience and trends in intraoperative complications in laparoscopic cholecystectomy
Authors: Hobbs M S , Mai Q , Knuiman M W , Fletcher D R , Ridout S C 
Published: May 2006

Abstract

Background
Intraoperative complications, particularly bile duct injuries (BDIs), have increased since the introduction of laparoscopic cholecystectomy (LC). This excess risk is expected to decline as surgeon experience in laparoscopic surgery increases.

Methods
This was a population-based study of trends in intraoperative injuries in 33 309 cholecystectomies carried out in Western Australia between 1988 and 1998, based on hospital discharge abstracts. Endpoints were identified from diagnostic and procedure codes in index or postoperative readmissions, or a register of endoscopic retrograde cholangiopancreatography procedures, and validated using hospital records. Multivariate analysis was used to estimate the risk of complications associated with potential risk factors.

Results
Following the introduction of LC in 1991, the prevalence of all complications doubled by 1994 then stabilized, whereas that of BDI declined after 1994. The risk of complications increased with age, was higher in men, teaching and country hospitals, and was higher for LC and more complicated operations. It was lower when intraoperative cholangiography was performed and with increasing surgeon experience. Approximately 20 per cent of all complications and 30 per cent of BDIs were attributable to surgeons who had performed 200 or fewer cholecystectomies in the previous 5 years.

Conclusion
The risk of intraoperative complications declined with increasing surgical experience and use of intraoperative cholangiography.
Neoadjuvant chemotherapy and resection of advanced synchronous liver metastases before treatment of the colorectal primary
Authors: Mentha G , Majno P E , Andres A , Rubbia-Brandt L , Morel P , Roth A D 
Published: May 2006

Abstract

Background
In many patients with advanced synchronous liver metastases from colorectal tumours, the metastases progress during treatment of the primary, precluding curative treatment. The authors have investigated a management strategy that involves high-impact chemotherapy first, resection of liver metastases second and finally removal of the primary tumour in patients with adverse prognostic factors.

Methods
Twenty consecutive patients with non-obstructive colonic (nine patients) or rectal (11 patients) cancer and advanced synchronous liver metastases were treated according to this strategy. Median age was 56 years. Patients received between two and six cycles of 5-fluorouracil, oxaliplatin and irinotecan-based chemotherapy. Data were collected prospectively.

Results
Overall survival rates at 1, 2, 3 and 4 years after the start of treatment were 85, 79, 71 and 56 per cent respectively, with a median survival of 46 months. Sixteen of the 20 patients had complete removal of liver metastases and colorectal tumours (resectability rate 80 per cent).

Conclusion
This new strategy produced resectability and survival rates better than those expected from the published data on patients with disease of similar severity. It allows initial control and downstaging of liver metastases, and delivery of preoperative radiotherapy for rectal cancer without the fear that liver metastases will meanwhile progress beyond the possibility of cure.
Palladium‐Catalyzed Cross‐Coupling Reactions of Silanolates: A Paradigm Shift in Silicon‐Based Cross‐Coupling Reactions
Authors: Denmark Scott. E. , Baird John D. 
Published: May 2006

AbstractThis paper chronicles the conceptual development, proof of principle experiments, and recent advances in the palladium‐catalyzed cross‐coupling reactions of the conjugate bases of organosilanols. The discovery that led to the design and refinement of this process represents a classical illustration of how mechanistic studies can provide a fertile ground for the invention of new reactions. On the basis of a working hypothesis (which ultimately proved to be incorrect) and the desire to effect silicon‐based cross‐coupling without the agency of fluoride activation, a mild and practical palladium‐catalyzed cross‐coupling of alkenyl‐, aryl‐, and heteroaryl silanolates has been developed. The mechanistic underpinnings, methodological extensions, and the successful applications of this technology to the synthesis of complex molecules are described.
Conformational Behavior of Pyrazine‐Bridged and Mixed‐Bridged Cavitands: A General Model for Solvent Effects on Thermal “Vase–Kite” Switching
Authors: Roncucci Pamela , Pirondini Laura , Paderni Giuseppe , Massera Chiara , Dalcanale Enrico , Azov Vladimir A. , Diederich François 
Published: May 2006

AbstractThe controllable switching of suitably bridged resorcin[4]arene cavitands between a “vase” conformation, with a cavity capable of guest inclusion, and a “kite” conformation, featuring an extended flattened surface, provides the basis for ongoing developments of dynamic molecular receptors, sensors, and molecular machines. This paper describes the synthesis, X‐ray crystallographic characterization, and NMR analysis of the “vase–kite” switching behavior of a fully pyrazine‐bridged cavitand and five other mixed‐bridged quinoxaline‐bridged cavitands with one methylene, phosphonate, or phosphate bridge. The pyrazine‐bridged resorcin[4]arene cavitand displayed an unexpectedly high preference for the kite conformation in nonpolar solvents, relative to the quinoxaline‐bridged analogue. This observation led to extensive solvent‐dependent switching studies that provide a detailed picture of how solvent affects the thermal vase–kite equilibration. As for any thermodynamic process in the liquid phase, the conformational equilibrium is affected by how the solvent stabilizes the two individual states. Suitably sized solvents (benzene and derivatives) solvate the cavity of the vase form and reduce the propensity for the vase‐to‐kite transition. Correspondingly, the kite geometry becomes preferred in bulky solvents such as mesitylene, incapable of penetrating the vase cavity. As proposed earlier by Cram, the kite form is preferred at low temperatures due to the more favorable enthalpy of solvation of the enlarged surface. Furthermore, the kite conformation is more preferred in solvents with substantial hydrogen‐bonding acidity: weak hydrogen‐bonding interactions between the mildly basic quinoxaline and pyrazine nitrogen atoms and solvent molecules are more efficient in the open kite than in the closed vase form. Vase‐to‐kite conversion is entirely absent in dipolar aprotic solvents lacking any H‐bonding acidity. Thermal vase–kite switching requires fully quinoxaline‐ or pyrazine‐bridged cavitands, whereas pH‐controlled switching is also applicable to systems incorporating only two or three such bridges.
Peculiarities of C60.− Coordination to Cobalt(II) Octaethylporphyrin in Ionic Multicomponent Complexes: Observation of the Reversible Formation of CoC(C60−) Coordination Bonds
Authors: Konarev Dmitri V. , Khasanov Salavat S. , Otsuka Akihiro , Saito Gunzi , Lyubovskaya Rimma N. 
Published: May 2006

AbstractIonic multicomponent complexes containing the C60− anion, cobalt(II) octaethylporphyrin (OEP), and the noncoordinating tetramethylphosphonium cation (TMP+), [(TMP+){CoIIOEP(C60−)}(C6H5CN)x(C6H4Cl2)1−x] (x≅0.75) (1), or the coordinating cation of N‐methyldiazabicyclooctane (MDABCO+), [{(MDABCO+)CoIIOEP(C60−)}(C6H5CN)x(C6H4Cl2)1−x] (x≅0.67) (2), were obtained. Diamagnetic σ‐bonded {CoIIOEP(C60−)} units in 1 have the Co⋅⋅⋅C(C60−) distance of 2.268(1) Å at 100 K and are stable up to 290 K. Both MDABCO+ and C60− coordinate to CoIIOEP in 2. In this case, a noticeably longer Co⋅⋅⋅C(C60−) distance of 2.508(4) Å was observed at 100 K. As a result, the unprecedented reversible formation of the CoC(C60−) coordination σ bond is realized in 2 and is accompanied by a transition from a paramagnetic to a diamagnetic state in the 50–250 K range. It was shown, for the first time, that the Co⋅⋅⋅C distance of about 2.51 Å is a boundary distance below which the CoC(C60−) coordination bond is formed.
Noncovalent Functionalization and Solubilization of Carbon Nanotubes by Using a Conjugated Zn–Porphyrin Polymer
Authors: Cheng Fuyong , Adronov Alex 
Published: May 2006

AbstractA highly soluble, conjugated Zn–porphyrin polymer was synthesized and found to strongly interact with the surface of single‐walled carbon nanotubes, producing a soluble polymer–nanotube complex. Successful complexation required the addition of trifluoroacetic acid to the solvent (THF). It was found that the complex remained soluble after excess free polymer was removed from solution, and could be centrifuged at high speed with no observable sedimentation. Furthermore, the polymer–nanotube assembly resulted in enhanced planarization and conjugation within the porphyrin polymer, which was manifested in a 127 nm bathochromic shift of the Q‐band absorption. Control experiments with the Zn–porphyrin monomer indicated that homogeneous solutions could be prepared by means of sonication, but the monomer–nanotube interactions were significantly weaker, leading to nanotube precipitation within minutes. Atomic force microscopy (AFM) studies indicated that the polymer enables exfoliation of nanotube bundles and is able to “stitch” multiple nanotubes together into a series of long, interconnected strands.
Synthesis and Characterization of the Oxynitride Y2Mo2O4.5N2.5 Pyrochlore: A Neutron Diffraction and Magnetic Study.
Authors: Martinez‐Lope M. J. , Casais M. T. , Alonso J. A. 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis and Crystal Structure of AlH2P3O10×2H2O; a New Structure‐Type for Layered Acid Phosphates.
Authors: Rishi Steven K. , Kariuki Benson M. , Checker Neal J. , Godber John , Wright Adrian J. 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Thermal Stability Study of BaAl2Si2O8:Eu2+ Phosphor Using Its Polymorphism for Plasma Display Panel Application.
Authors: Im Won Bin , Kim Yong‐Il , Jeon Duk Young 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
LaFePdO3 Perovskite Automotive Catalyst Having a Self‐Regenerative Function.
Authors: Tanaka Hirohisa , Tan Isao , Uenishi Mari , Taniguchi Masashi , Kimura Mareo , Nishihata Yasuo , Mizuki Jun'ichiro 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Inverse Perovskites (Eu3O)E with E: Sn, In — Preparation, Crystal Structures and Physical Properties.
Authors: Kirchner M. , Schnelle W. , Niewa R. 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
[Ho5(H2O)16 (OH)2As6W64O220]25‐, a Large Novel Polyoxoanion from Trivacant Keggin Fragments.
Authors: Drewes Daniel , Piepenbrink Markus , Krebs Bernt 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Sterically Congested “Roofed” 2‐Iminothioethers as New Chiral Ligands for Palladium‐Catalyzed Asymmetric Allylic Alkylation.
Authors: Tokuda Ryoh , Matsunaga Hirofumi , Ishizuka Tadao , Nakajima Makoto , Kunieda Takehisa 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Enantioselective Alkylation of Reissert Compounds in Phase Transfer Catalyzed Reactions.
Authors: Brozda Danuta , Hoffman Krzysztof , Rozwadowska Maria D. 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Rhodium N‐Heterocyclic Carbene Catalyzed [4 + 2] and [5 + 2] Cycloaddition Reactions.
Authors: Lee Sang Ick , Park Se Yeoun , Park Ji Hoon , Jung Il Gu , Choi Soo Young , Chung Young Keun , Lee Bun Yeoul 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Propionic Acids in Organic Synthesis: Novel Synthesis of Benzimidazole, 3,1‐Benzoxazine, 3‐Aminoquinazoline and 3‐Aminothieno[2,3‐d]pyrimidine Derivatives Containing 2‐Naphthyl Propionyl Moiety.
Authors: Al‐Sehemi Abdullah G. M. , El‐Sharief A. M. Sh. , Ammar Y. A. 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Highly Selective Aerobic Oxidation of Alcohol Catalyzed by a Gold(I) Complex with an Anionic Ligand.
Authors: Guan Bingtao , Xing Dong , Cai Guixing , Wan Xiaobin , Yu Nan , Fang Zhao , Yang Liping , Shi Zhangjie 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Selective Reduction of Aromatic Nitriles to Aldehydes by Lithium Diisobutylpiperidinohydroaluminate (LDBPA).
Authors: Ha Ji Hyun , Ahn Jin Hee , An Duk Keun 
Published: May 2006

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.