bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the Transition Metal Ion Induced Fluorescence Enhancement of 1,8‐Naphthalimide Derivatives†
Authors: Wen Guo‐Tao , Zhu Man‐Zhou , Wang Zhuo , Meng Xiang‐Ming , Hu Hui‐Yuan , Guo Qing‐Xiang 
Published: September 2006

AbstractTwo fluorosensor systems have been designed and synthesized with their photophysical properties and fluorescence responses toward the transition metal ions studied. The fluorosensor was composed of 1,8‐naphthalimide and 4‐chloro‐1,8‐naphthalimide as fluorophore respectively, an amino moiety as the receptor and a hydrocarbon chain as the spacer to link the fluorophore and receptor. Fluorescence intensity of these systems is very weak due to the process of the efficient intramolecular photoinduced electron transfer (PET) in the absence of metal ions. Titration of the transition metal ions can switch on the fluorescence immediately. The intensity of released fluorescence is even higher than the expected from the consideration of the PET in these systems. It may be rationalized that the receptor bound to transition metal ions and the solvation of the fluorophore by the water molecules from the hydrated transition metal salts, may significantly cause fluorescence enhancement.
Stereospecific Synthesis of (Z)‐α‐Fluoro‐β‐trifluoromethyl Vinyl Iodides and Their Application to the Synthesis of Polyfluorinated Thienyl Alkadienes†
Authors: Shen Yan‐Chang , Wang Guo‐Ping 
Published: September 2006

AbstractThe direct iodination of polyfluorinated vinyl stannanes by tin‐iodine exchange methodology was achieved giving(Z)‐α‐fluoro‐β‐trifluoromethyl vinyl iodides stereospecifically. Changing the substituent in R group from the electron‐withdrawing group to electron‐donating group led to an increase in the yield from 78% to 90%, while it was moved from para to meta position the reaction did not afford a dramatic change in the yield (90% to 95%). In addition, this reaction also can be applied to the vinyl stannane with heterocyclic group. The further coupling reaction of prepared vinyl iodide containing heterocyclic moiety with (Z)‐α‐fluoro‐β‐trifluoromethylstannanes gave polyfluorinated heterocyclic alkadienes with 2E,4E‐selectivity.
Correlating Expression Data with Gene Function Using Gene Ontology†
Authors: Liu Qi , Deng Yong , Wang Chuan , Shi Tie‐Liu , Li Yi‐Xue 
Published: September 2006

AbstractClustering is perhaps one of the most widely used tools for microarray data analysis. Proposed roles for genes of unknown function are inferred from clusters of genes similarity expressed across many biological conditions. However, whether function annotation by similarity metrics is reliable or not and to what extent the similarity in gene expression patterns is useful for annotation of gene functions, has not been evaluated. This paper made a comprehensive research on the correlation between the similarity of expression data and of gene functions using Gene Ontology. It has been found that although the similarity in expression patterns and the similarity in gene functions are significantly dependent on each other, this association is rather weak. In addition, among the three categories of Gene Ontology, the similarity of expression data is more useful for cellular component annotation than for biological process and molecular function. The results presented are interesting for the gene functions prediction research area.
Indium Trichloride‐Mediated Facile Synthesis of 3‐(Substituted methylthio)‐4‐phenyl‐5‐(3,4,5‐trimethoxyphenyl)‐4H‐1,2,4‐triazole in Water†
Authors: Yang Song , Song Bao‐An , Jin Lin‐Hong , Hu De‐Yu 
Published: September 2006

AbstractAn environmentally benign and efficient process for the preparation of 3‐(substituted methylthio)‐4‐phenyl‐5‐ (3,4,5‐trimethoxyphenyl)‐4H‐1,2,4‐triazole was achieved by the reaction of 4‐phenyl‐5‐(3,4,5‐trimethoxyphenyl)‐ 4H‐1,2,4‐triazole‐3‐thiol with different halides in aqueous media mediated by indium trichloride in high yields.
Plasma interleukin‐6 levels are increased in subjects with impaired glucose tolerance but not in those with impaired fasting glucose in a cohort of Italian Caucasians
Authors: Cardellini Marina , Andreozzi Francesco , Laratta Emanuela , Marini Maria Adelaide , Lauro Renato , Hribal Marta Letizia , Perticone Francesco , Sesti Giorgio 
Published: September 2006

AbstractBackgroundWhile the relationship between impaired glucose tolerance (IGT) and circulating interleukin‐6 (IL‐6) is well established, there is no information whether IL‐6 levels are elevated in impaired fasting glucose (IFG).MethodsTo this end, we examined the relationship between plasma IL‐6 concentration and different degrees of glucose homeostasis in a cohort of 470 Italian Caucasian subjects comprising 236 normal glucose tolerant (NGT), 49 IFG, 51 IGT, and 134 type 2 diabetic subjects.ResultsWe observed that IL‐6, CRP and fibrinogen levels were higher in subjects with IGT or type 2 diabetes as compared with NGT and IFG subjects. Univariate correlations between IL‐6 concentrations and metabolic variables in the whole cohort showed that IL‐6 levels were positively correlated with age, BMI, waist, systolic and diastolic blood pressure, fasting plasma glucose, triglycerides, CRP, fibrinogen, and negatively correlated with insulin sensitivity, IGF‐I and HDL. In a subgroup analysis including NGT, IFG and IGT (n = 336), IL‐6 levels were positively correlated with age, BMI, waist, systolic and diastolic blood pressure, triglycerides, CRP, fibrinogen, fasting insulin, 2 h post‐load glucose, and negatively correlated with insulin sensitivity, IGF‐I and HDL. Stepwise linear regression analysis in a model including gender, age, BMI, waist, glucose tolerance status, fasting plasma glucose, 2 h post‐load glucose, triglycerides, HDL, fasting insulin, and insulin sensitivity revealed that waist was the only independent variable associated with IL‐6 levels accounting for 21.0% of its variation (P < 0.0001).ConclusionsThese data show that IGT and type 2 diabetes, but not IFG, are associated with elevated plasma IL‐6 levels. Copyright © 2006 John Wiley & Sons, Ltd.
Gliclazide protects human islet beta‐cells from apoptosis induced by intermittent high glucose
Authors: Del Guerra S , Grupillo M , Masini M , Lupi R , Bugliani M , Torri S , Boggi U , Del Chiaro M , Vistoli F , Mosca F , Del Prato S , Marchetti P 
Published: September 2006

AbstractBackgroundDecreased beta‐cell mass, mainly due to apoptosis, is crucial for the development and progression of type 2 diabetes. Chronic exposure to high glucose levels is a probable underlying mechanism, whereas the role of oral anti‐diabetic agents (sulphonylureas in particular) is still unsettled.MethodsTo directly investigate more on such issues, we prepared isolated human islets, which were then cultured for 5 days in continuous normal glucose concentration (NG, 5.5 mmol/L) or normal and high (HG, 16.7 mmol/L) glucose levels (alternating every 24 h), with or without the addition of therapeutical concentration (10 µmolL) of gliclazide or glibenclamide.ResultsIntermittent high glucose caused a significant decrease of glucose‐stimulated insulin secretion, which was not further affected by either sulphonylurea. Apoptosis, as assessed by electron microscopy, was also significantly increased by alternating high glucose exposure, which was accompanied by altered mitochondria morphology and density volume, and increased concentrations of nitrotyrosine, a marker of oxidative stress. Gliclazide, but not glibenclamide, was able to significantly reduce high glucose induced apoptosis, mitochondrial alterations, and nitrotyrosine concentration increase.ConclusionTherefore, gliclazide protected human beta‐cells from apoptosis induced by intermittent high glucose, and this effect was likely to be due, at least in part, to the anti‐oxidant properties of the molecule. Copyright © 2006 John Wiley & Sons, Ltd.
Metformin prolongs the postprandial fall in plasma ghrelin concentrations in type 2 diabetes
Authors: English P. J. , Ashcroft A. , Patterson M. , Dovey T. M. , Halford J. C. G. , Harrison J. , Eccleston D. , Bloom S. R. , Ghatei M. A. , Wilding J. P. H. 
Published: September 2006

AbstractBackgroundWeight loss is difficult to achieve in type 2 diabetes and many therapies are associated with weight gain, an effect attenuated by metformin. We studied the effects of metformin on energy expenditure, appetite and the regulation of PYY and ghrelin in type 2 diabetes.MethodsPlasma peptide YY (PYY), ghrelin, resting metabolic rate (RMR), postprandial thermogenesis (PPTG), and appetite ratings were measured at baseline and following a mixed meal in 11 type 2 diabetic subjects treated with diet alone (T2D) and 10 treated with metformin monotherapy (T2MF). The groups were similar in age, gender and adiposity.ResultsThere were no differences in baseline anthropometric, or metabolic variables between the groups. Postprandially, plasma ghrelin fell equally in both groups (23% versus 24.5%, p < 0.05 versus baseline, p = NS between groups) but were reduced for longer in T2MF (below baseline 60–240 min T2MF versus 60–180 min T2D) coincidentally with a prolonged sensation of fullness and suppression of hunger in the metformin‐treated group. There were no differences in PYY concentrations, RMR or PPTG.ConclusionsMetformin prolongs the postprandial fall in ghrelin concentrations. These effects may prolong the inter‐meal interval, thereby decreasing snack intake and daily energy intake, promoting weight loss. Copyright © 2006 John Wiley & Sons, Ltd.
Chiral 1,10‐Phenanthroline‐Bridged Calix[6]arenes
Authors: Konrad Serge , Bolte Michael , Näther Christian , Lüning Ulrich 
Published: September 2006

AbstractSeveral approaches to chiral derivatives of the 1,10‐phenanthroline‐bridged calix[6]arene 3 have been investigated, and seven new chiral calix[6]arenes have been synthesized. The C2‐symmetric axially chiral bimacrocycle 5 has been synthesized as racemic mixture; calixarenes 8, 14, 18, 19, 20 and 21 carrying chiral substituents (camphorsulfonyl, myrtanyl) have been prepared using enantiomerically pure reagents. Three chiral bimacrocycles 5, 19 and 20 have also been analyzed by X‐ray analyses. All compounds have been tested as ligands for copper ions in the CuI‐catalyzed cyclopropanation of styrene and indene.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Long Chain‐Substituted and Triply Functionalized Molecular Knots – Synthesis, Topological Chirality and Monolayer Formation
Authors: Böhmer Athanasia , Brüggemann Jens , Kaufmann Astrid , Yoneva Albena , Müller Sonja , Müller Walter M. , Müller Ute , Vergeer Frank W. , Chi Lifeng , De Cola Luisa , Fuchs Harald , Chen Xiaoming , Kubota Takateru , Okamoto Yoshio , Vögtle Fritz 
Published: September 2006

AbstractNew topological chiral molecular knots (knotanes) 3a–6 of the amide type were substituted with long aliphatic side chains (butyloxy, hexyloxy, octenyloxy, decyloxy) and with p‐bromobenzyloxy and oligoethylene glycol ether units, which resulted in improved solubility and enhanced potential for racemate separation. In consequence, the knotanes with longer substituted chains could be separated even on commercially available noncovalently bound chiral stationary phases. The (p‐bromobenzyloxy)‐knotane 6 and the octenyloxy‐knotane 4 were synthesized with the intention of using their functional sidechains in further reactions, 6 being used in Suzuki‐type reactions, while 4 was consequently allowed to react in the presence of Grubbs catalyst in metathesis reactions. The achieved solubility allowed us to test the abilities of the alkyl chain‐substituted knotanes 3a–c and the (p‐bromobenzyloxy)‐knotane 6 to form Langmuir–Blodgett films. The assemblies were investigated on mica by AFM technique. A key point of focus was the (topological) chirality of the long chain‐substituted knotanes. To address this point, the racemates were enantioseparated by HPLC on various chiral phases, and the obtained pure enantiomers were found to exhibit pronounced Cotton effects in their circular dichroism spectra. The absolute configurations of all new knots were derived by comparison with the unsubstituted knot. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The Stereochemical Course of the Generation and Interception of aSix‐Membered Cyclic Allene: 3δ2‐1H‐Naphthalene (2,3‐Didehydro‐1,2‐dihydronaphthalene)
Authors: Christl Manfred , Braun Martin , Fischer Hartmut , Groetsch Stefan , Müller Germar , Leusser Dirk , Deuerlein Stephan , Stalke Dietmar , Arnone Mario , Engels Bernd 
Published: September 2006

AbstractThe bromofluorocarbene adduct rac‐1 of indene, possessing the fluorine atom at the endo position, is a useful substrate for the generation of the isonaphthalene 4 by the Doering–Moore–Skattebøl reaction. By resolution of rac‐1, an enantiomerically pure precursor of a six‐membered cyclic allene was obtained for the first time. The treatment of (+)‐ or (–)‐1, dissolved in 2,5‐dimethyl‐, 2‐tert‐butyl‐5‐methyl‐, or 2,5‐bis(tert‐butyl)furan, with methyllithium gave rise to the [4+2] cycloadducts 6 of 4 to the furans. It was shown by means of HPLC on Chiralcel OD that the formation of 6 proceeded with about 40 % ee, and that this value was independent of the type and concentration of the furan, and the reaction temperature. The absolute configurations of the enantiomers 1, as well as those of the enantiomers 6, were determined by simulation of the CD spectra by quantum chemical methods and by the comparison of them with the experimental spectra. In the case of (+)‐1, the reliability of this procedure was checked by X‐ray crystal structure analysis. On the basis of these results, a model is proposed for the steric course of the reaction sequence, leading from a pure enantiomer 1 to the 70:30 mixtures of the product enantiomers 6. The use of indene as trapping reagent for 4 furnished the [2+2] cycloadduct 15. For the preparation of rac‐15, the particularly simple one‐pot procedure was employed, in which indene, tetrabromomethane, and methyllithium were combined and in which the dibromocarbene adduct 2 of indene serves as precursor of 4. Compound 2 could not be isolated, but was characterised by low‐temperature 1H NMR spectra. The conversion of (+)‐ or (–)‐1 into 4 in the presence of indene afforded 15 only with a very low enantioselectivity. The constitutions and the relative configurations of 15 as well as the compounds 8 and 16, which resulted from thermolysis of the cycloadducts 6b and 15, respectively, were elucidated by X‐ray crystal diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
C2‐Chiral Substituted cis‐1,3,5,7‐Tetraazadecalins as Proton Sponges:A Computational Study
Authors: Singh Ajeet , Chakraborty Shampa , Ganguly Bishwajit 
Published: September 2006

AbstractDensity functional quantum chemical calculations at the B3LYP/6‐31+G* and B3LYP/6‐31+G** levels have been performed to calculate the proton affinities of chiral cis‐1,5‐diazadecalins 1,2 and substituted cis‐1,3,5,7‐tetraazadecalin 3. The calculated gas‐phase proton affinities of cis‐1,3,5,7‐tetraazadecalins are higher than that of 1,8‐bis(dimethylamino)naphthalene (4). cis‐1,5‐Diazadecalins show lower proton affinities compared with those of substituted 1,3,5,7‐tetraazadecalins. Cooperative and anomeric effects seem to be responsible for the additional stabilization of the protonated forms of 1,3,5,7‐tetraazadecalins. Intramolecular proton transfer energies have been predicted for these amines and discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Dimethoxycarbene: Conformational Analysis of a Reactive Intermediate
Authors: Reisenauer Hans Peter , Romanski Jaroslaw , Mloston Grzegorz , Schreiner Peter R. 
Published: September 2006

AbstractDimethoxycarbene was prepared from an oxadiazoline precursor under high‐vacuum flash pyrolysis (HVFP) conditions and was trapped at low temperatures by matrix isolation techniques (Ar, 10 K). The excellent agreement between the computed [CCSD(T)/cc‐pVDZ] IR spectrum of the mixture of conformers of dimethoxycarbene and the experimentally measured IR absorptions allows a detailed analysis ofthe conformational preference of dimethoxycarbene. ItsUV spectrum is in agreement with earlier studies and ourTD‐B3LYP/6‐311+G(d,p) computations. The computed [CCSD(T)/cc‐pVDZ] rotational profile is rather steep and separates the s‐trans,s‐trans and s‐cis,s‐trans conformers by a 16 kcal mol–1 barrier, whilst the s‐cis,s‐cis conformer is too high‐lying to be observable (+17 kcal mol–1). In marked contrast with the gauche,gauche minimum of dimethoxymethane, the s‐trans,s‐trans conformer of dimethoxycarbene is slightly preferred (0.5 kcal mol–1). The s‐cis,s‐trans conformer equilibrates at the high temperatures required during HFVP generation and both conformers can be identified in the IR spectrum of the argon matrix at 10 K. The conformational preference is partly due to the minimization of the overall dipole moment in the s‐trans,s‐trans conformer. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Conformational Analysis of C‐4′‐Modified (2‐Oxabicyclo[3.1.0]hexyl)pyrimidine Nucleosides
Authors: Gagneron Julien , Gosselin Gilles , Mathé Christophe 
Published: September 2006

AbstractWe report on the synthesis of hitherto unknown pyrimidine nucleoside analogues bearing the 2‐oxabicyclo[3.1.0]hexane scaffold (5, 6, 8, 13–17 and 19) with various modifications at the C‐4′ position including methylene, azido, and arabino‐like configuration. Conformational analysis on the nucleoside analogues 6, 14 and 17 indicates that the conformation of such C‐4′‐modified nucleoside analogues was restricted in the South‐East hemisphere of the pseudorotation cycle (between a 0T1 and a 2E conformation). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Study of the Substituent‐Influenced Anomeric Effect in the Ring‐Chain Tautomerism of 1‐Alkyl‐3‐aryl‐naphth[1,2‐e][1,3]oxazines
Authors: Szatmári István , Tóth Diána , Koch Andreas , Heydenreich Matthias , Kleinpeter Erich , Fülöp Ferenc 
Published: September 2006

AbstractThe stabilities of the trans (B) and cis (C) tautomeric ring forms that are experimentally observed in the ring‐chain tautomeric interconversion of 1‐alkyl‐3‐aryl‐2,3‐dihydro‐1H‐naphth[1,2‐e][1,3]oxazines has been investigated. Stability differences are explained by the analysis of the natural bond orbital results for the lone pairs of electrons that are on the heteroatoms in the oxazine ring system and by regression analysis of the calculated 13C NMR chemical shift values. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Genotyping of simple sequence repeat factors implicated in shadow band generation revisited
Authors: Olejniczak Marta , Krzyzosiak Wlodzimierz J. 
Published: September 2006

AbstractPCR amplification of microsatellite sequences generates, besides the main product corresponding to allele size, also additional, undesired products usually shorter by multiples of the repeated unit. These extra products known as shadow bands or stutter products may complicate genotyping. The mechanism by which these artifacts are formed is not well understood and so no effective remedy has been found to cope with these spurious products. In this study, using the DNA templates containing the CAG/CTG repeats flanked by gene‐specific sequences and universal priming sites, we analyzed the effects of many PCR variables on the shadow band generation. The most important result was that at the decreased temperature of the denaturation step during PCR cycling the shadow bands were either not formed or were strongly suppressed. Several possible sources of this effect are discussed.
Factors associated with treatment seeking in a community sample of European American and Mexican American women with eating disorders
Authors: Cachelin Fary M. , Striegel‐Moore Ruth H. , Regan Pamela C. 
Published: September 2006

AbstractThe purpose of this study was to investigate factors associated with treatment seeking in a community sample of European American and Mexican American women with eating disorders. We also explored which variables were associated with receiving treatment. Participants were 190 women with eating disorders (80 Mexican American, 110 European American) who were diagnosed using the SCID‐IV and Eating Disorder Examination. Results indicated that treatment seeking is associated with ethnicity (i.e. being European American), suffering from bulimia nervosa and more frequent purging, longer duration of disorder and psychiatric comorbidity and, for Mexican American women, higher degree of acculturation. Detection and treatment of eating disorder was associated with ethnicity (European American), earlier age of onset and lower BMI. Given the debilitating and chronic nature of eating disorders, further knowledge of factors that impede or facilitate help seeking and detection and treatment is needed. Copyright © 2006 John Wiley & Sons, Ltd and Eating Disorders Association.
Does the economy affect teenage substance use?
Authors: Arkes Jeremy 
Published: September 2006

AbstractThis research examines how teenage drug and alcohol use responds to changes in the economy. In contrast to the recent literature confirming pro‐cyclical alcohol use among adults, this research offers strong evidence that a weaker economy leads to greater teenage marijuana and hard‐drug use and some evidence that a weaker economy also leads to higher teenage alcohol use. The findings are based on logistic models with state and year fixed effects, using teenagers from the NLSY‐1997. The evidence also indicates that teenagers are more likely to sell drugs in weaker economies. This suggests one mechanism for counter‐cyclical drug use – that access to illicit drugs is easier when the economy is weaker. These results also suggest that the strengthening economy in the 1990s mitigated what would otherwise have been much larger increases in teenage drug use. Copyright © 2006 John Wiley & Sons, Ltd.
Cognitive testing in early phase clinical trials: outcome according to adverse event profile in a Phase I study
Authors: Collie Alex , Maruff Paul , Snyder Peter J. , Darekar Miss Amanda , Huggins John P. 
Published: September 2006

AbstractBackgroundIt has been proposed that objective cognitive testing provides additional information to that collected via adverse event (AE) recordings. However, in clinical trials of compounds with potentially negative effects on cognition, the results of cognitive testing may overlap with AE recordings.AimsTo examine cognitive function in subjects who do and do not report sedation‐related AEs in a Phase I clinical trial.MethodsFive computerized cognitive tasks were administered to 28 healthy male volunteers enrolled in a simulated Phase I study using midazolam to induce sedation‐related AEs and cognitive dysfunction. For each subject, the magnitude of cognitive change between pre‐dose and 1 hr post‐dose assessments was calculated. Group and individual level cognitive outcome was compared between subjects who did and did not report sedation‐related AEs following administration of 1.75 and 5.25 mg midazolam.ResultsAt both doses of midazolam, cognitive dysfunction was observed in both subject groups (i.e., those who did and did not report AEs). Analysis of individual outcomes identified consistent cognitive dysfunction among subjects who reported sedation‐related AEs. Further, in the 5.25 mg condition a subset of individuals (66.7%) who did not report sedation‐related AEs nevertheless displayed substantial cognitive dysfunction.ConclusionsFollowing administration of oral midazolam, there is a dissociation between sedation‐related AE recordings and performance on computerized cognitive tests of motor function, attention, strategy use and problem solving, learning and delayed recall. Inclusion of computerized cognitive tests in early phase trials may allow identification of subtle cognitive change, beyond that which is possible by self‐report and clinical observation. Copyright © 2006 John Wiley & Sons, Ltd.