bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Potent Integrin Antagonist from a Small Library of Cyclic RGD Pentapeptide Mimics Including Benzyl‐Substituted Azabicycloalkane Amino Acids
Authors: Arosio Daniela , Belvisi Laura , Colombo Lino , Colombo Matteo , Invernizzi Donatella , Manzoni Leonardo , Potenza Donatella , Serra Massimo , Castorina Massimo , Pisano Claudio , Scolastico Carlo 
Published: September 2008

AbstractA small library of cyclic RGD pentapeptide mimics, including benzyl‐substituted azabicycloalkane amino acids, was synthesized with the aim of developing active and selective integrin antagonists. In vitro binding assays established one particular compound with affinity for both the αvβ3and the αvβ5integrins. The synthesis in solution and the in vitro screening of these RGD derivatives, as well as the determination of the conformational properties of the integrin ligands by spectroscopic and computational methods are described.
HP‐NMR Study of the Pd‐Catalyzed Methoxycarbonylation of Styrene Using Monodentate and Bidentate Phosphane‐Modified Systems
Authors: Muñoz Bianca K. , Santos Garcia Eva , Godard Cyril , Zangrando Ennio , Bo Carles , Ruiz Aurora , Claver Carmen 
Published: September 2008

AbstractCatalytically active palladium systems bearing the monodentate phosphetane ligand 1 and diphosphane 2 were studied by multinuclear NMR and HP‐NMR spectroscopy under methoxycarbonylation conditions. The reaction of the complex [PdCl2(1)2] (1a) with pTsOH yields the dimeric complex [PdCl(μ‐Cl)(1)]2 (1b), which was characterized by multinuclear NMR spectroscopy and X‐ray crystallography. The isolated complex 1b was tested as a precursor in the methoxycarbonylation of styrene, providing poor activity and enantioselectivity. Evidences for the protonation of ligand 1 under catalytic conditions were obtained. When complex [Pd(OTs)(OH2)(R,R‐bdpp)][OTs] (2b) was used as the catalyst precursor evidences for both hydride and methoxycarbonylation mechanisms were achieved. Two isomeric forms of [Pd(π‐methylbenzyl)(R,R‐bdpp)], 2h and 2i, were characterized by multinuclear NMR spectroscopy and DFT calculations. The results obtained by DFT calculations showed that the two most stable isomers contain the ligand bdpp in the “chair” conformation and that both isomers have very similar energies. The hydrido‐carbonyl‐bridged complex [Pd2(μ‐H)(μ‐CO)(R,R‐bdpp)2][OTs] (2e) was also detected under catalytic conditions. Deuterium labeling experiments using [D4]MeOH and GC‐MS analysis of the unconverted substrate and products were performed and the results indicate that the styrene insertion step into the Pd–H bond of the catalyst is irreversible when the phosphetane containing system is used, whereas this step is reversible when the diphosphane precursor is used as the incorporation of deuterium was only observed in the latter case.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Soft–Soft Interactions Involving Iodoselenophosphonium Cations: Supramolecular Structures of Iodine Adducts of Bulky Trialkylphosphane Selenides
Authors: du Mont Wolf‐W. , Bätcher Michael , Daniliuc Constantin , Devillanova Francesco A. , Druckenbrodt Christian , Jeske Jörg , Jones Peter G. , Lippolis Vito , Ruthe Frank , Seppälä Emma 
Published: September 2008

AbstractThe reactions of trialkylphosphane selenides tBuniPr3–nPSe (n = 3: 1a; n = 2: 1b; n = 1: 1c; n = 0: 1d) with iodine are studied with the help of heteronuclear NMR spectroscopy, vibrational spectroscopy, and X‐ray crystal structure determinations. The reaction of 1a with one equivalent of iodine provides, after crystallization from dichloromethane/pentane, solid 2a, which consists of pairs of molecular adducts tBu3PSe–I–I, together with chains of alternating [(tBu3PSe)2I]+ and I3– ions. The addition of iodine to 1b, 1c, and 1d in a 1:1 molar ratio furnishes ionic solids with the formulation [(tBuniPr3–nPSe)2I]+[I3]– (n = 2: 2b; n = 1: 2c; n = 0: 2d). Compounds 2a–2d exhibit supramolecular structures based on various kinds of weak Se···I and Se···Se interactions. In 2a, the uncharged molecules form dimers through Se···Se contacts, while the anions and cations assemble to form chains through linear P–Se···Ianion contacts. The ionic compounds 2b and 2d consist of the same type of chains, although they are not isotypic to each other. The two independent formula units of 2c are topologically different; one forms cation–anion chains analogous to those of 2b and 2d, whereas the other forms cation chains through Se···Se contacts. Se···I contacts between the latter chains and triiodide anions are very long but seem to be structurally significant; for such contacts, at well above the sum of the van der Waals radii, we propose the term tertiary contacts. On using more than one equivalent of I2, compounds corresponding to the formulation tBuniPr3–nPSeIx (x = 3, n = 3: 3a; x = 4, n = 1: 4c; x = 7, n = 2 and 0: 5b and 5d) were isolated as single crystals. Ionic 3a contains pairs of cations [(tBu3PSe)2I]+, connected by Se···Se contacts, located between corrugated layers of polymeric I5– anions. Compound 4c consists of two independent formula units tBuiPr2PSeI2·I2, which could, however, be regarded as tBuiPr2PSeI+·I–·I2 because of the long I–I distance adjacent to Se. To a fair approximation, the packing of the two units is independent; unit 1 forms dimers (···Se–I–I···I–I···)2, whereas the same motif in unit 2 forms chains. The structural subunits are linked through further contacts involving terminal iodine atoms from tBuiPr2PSeI···I units, which thereby form μ3‐bridging units, and by additional I–I···Se contacts. In 5b,iodide‐bridged cations [tBu2iPrPSeI···I···ISePiPrtBu2]+ are anchored to a polyiodide network of formal composition I11–[= (I–)(I2)5] through I···I contacts. Except for one I···I contact, the polyiodide is two‐dimensional, although highly puckered. In 5d, [iPr3PSeI]+ cations and I2 molecules exhibit weak I···I interactions with I– units from puckered square‐net‐like polyiodide layers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A4Ge9 (A = K, Rb) as Precursors for Hg‐Substituted Clathrate‐I Synthesis: Crystal Structure of A8Hg3Ge43
Authors: Kaltzoglou Andreas , Ponou Siméon , Fässler Thomas F. 
Published: September 2008

AbstractThe Hg‐substituted type‐I clathrates A8Hg3+xGe43–x (A = K, Rb) were obtained by solid‐state reactions from the corresponding Zintl phases A4Ge9 and Hg or HgO. The crystal structures of the compounds were determined by single‐crystal and powder X‐ray diffraction methods. They crystallize in the space group Pm$\bar {3}$n, with a = 10.849(1) Å and x = 0.19(5) for K8Hg3+xGe43–x (1) and a = 10.875(1) Å and x = 0.03(7) for Rb8Hg3+xGe43–x (2). Specific atomic positions (6c site) of the Ge framework are partially substituted by Hg atoms, whereas the alkali‐metal atoms reside at the center of the cavities. Both compounds exceed the electron‐counting rule for Zintl phases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis, Characterization, and In Vitro Antitumor Activity of New Amidineplatinum(II) Complexes Obtained by Addition of Ammonia to Coordinated Acetonitrile
Authors: Intini Francesco P. , Pellicani Raffaella Z. , Boccarelli Angela , Sasanelli Rossella , Coluccia Mauro , Natile Giovanni 
Published: September 2008

AbstractNew cis‐ and trans‐dichloridoplatinum(II) complexes, which contain two amidine ligands or one amidine and one ammine ligand, cis‐ and trans‐[PtCl2{(Z)‐HN=C(NH2)CH3}2] (1) and cis‐ and trans‐[PtCl2(NH3){(Z)‐HN=C(NH2)CH3}] (2), have been prepared from the corresponding nitrile complexes by amminolysis in thf solution. All synthesized compounds were characterized by elemental analysis, ESI‐MS, and IR and NMR spectroscopy. Amidines are isosters of iminoethers and ketimines. The trans isomers of the platinum complexes of the latter are endowed with an unexpectedly high antitumor activity. An important feature of complexes 1 and 2, as compared to iminoethers, is the exclusive preference for the Z configuration of the amidine ligand(s). The tumor cell growth inhibitory potency of the amidine compounds was tested towards a pair of human ovarian tumor cell lines A2780 (cancer cells sensitive to cisplatin) and A2780cisR (cancer cells with acquired resistance to cisplatin), and compared to that of cisplatin. From the obtained results it appears that the resistance factor is lower for cis‐amidine complexes as compared to cisplatin, and for trans compounds it is lower as compared to cis compounds.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Terpyridineplatinum(II) Incorporation in N‐Methylpyrrole‐Based Polyamides by Solid Phase Techniques
Authors: van Holst Marcelis , Le Pevelen Delphine , Aldrich‐Wright Janice 
Published: September 2008

AbstractThe incorporation of terpyridineplatinum(II) centres into sequence‐selective polyamides has been explored in this study, with the aim of producing cytotoxic molecules that display DNA sequence specificity. To facilitate this a terpyridineplatinum(II)‐based metallointercalator has been developed, which can be incorporated into sequence‐selective polyamides using standard machine‐assisted peptide coupling techniques. A novel N‐methylpyrrole‐based metallopolyamide, containing the new terpyridineplatinum(II) moiety, was also synthesised to validate this new method of incorporation.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Chemical and enzymatic interesterification of tristearin/triolein‐rich blends: Microstructure and polymorphism
Authors: Ahmadi Latifeh , Wright Amanda J. , Marangoni Alejandro G. 
Published: September 2008

AbstractMixtures of fully hydrogenated canola oil and high‐oleic sunflower oil were interesterified chemically and enzymatically with sodium methoxide and Candida antarctica lipase, respectively. Polymorphic behavior and crystal morphology of the10–100% blends before and after interesterification were studied using powder X‐ray diffraction spectroscopy and polarized light microscopy. X‐ray analysis revealed a predominance of the β' form in the IE‐blends (interesterified, both chemical and enzymatic) and the β form crystals in the NI‐blends (non‐interesterified). Dilution and crystallization at 20, 30, 40 and 50 °C did not change the polymorphism of the NI‐blends, but did in the IE‐blends. Small changes in the long spacings of the blends after interesterification were observed. Small‐angle reflections centered at 45 Å suggested the presence of a 2L lamellar crystalline structure. Needle‐like crystals were predominant in the IE‐blends while large symmetrical spherulites were observed in the NI‐blends crystallized at 30 °C for 24 h. Over 75% of the structural elements had areas between 1 and 20 µm2 in the NI‐ and IE‐blends, and the NI‐blends showed a higher percentage of crystals in this range compared to the IE‐samples. The box counting dimension (Db) increased as a function of crystalline area fraction in polarized light micrographs of the samples. Moreover, a higher Db in the chemically interesterified sample relative to the enzymatically interesterified sample at an equivalent area fraction, was attributed to the homogeneity in the distribution of crystalline mass.
Stereoselective Synthesis of (+)‐Goniodiol, (+)‐Goniotriol, (–)‐Goniofupyrone, and (+)‐Altholactone Using a Catalytic Asymmetric Hetero‐Diels–Alder/Allylboration Approach
Authors: Favre Annaïck , Carreaux François , Deligny Michael , Carboni Bertrand 
Published: September 2008

AbstractThe stereoselective total synthesis of several members of the styryllactone family was achieved efficiently from common intermediate 8, prepared by a catalytic asymmetric inverse‐electron‐demand hetero‐Diels–Alder/allylboration sequence. The transformation of 8 into α,β‐unsaturated lactone led to the preparation of (+)‐goniodiol (1) in a reduced number of steps. The epoxidation reaction was used to generate the remaining stereogenic centers on the lactone moiety of 8, and these intermediates were then elaborated into (+)‐goniotriol (2), (–)‐goniofupyrone (3), and (+)‐altholactone (4) by an isomerization or cyclization step.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A Coumarin‐Based Chromogenic Sensor for Transition‐Metal Ions Showing Ion‐Dependent Bathochromic Shift
Authors: Lin Weiying , Yuan Lin , Cao Xiaowei , Tan Wen , Feng Yanming 
Published: September 2008

AbstractCoumarin pyridyl ketone1was designed and synthesized as a new chromogenic sensor for transition‐metal ions. Remarkably, the chemosensor showed ion discrimination by exhibiting different extents of bathochromic shifts: 118 nm for Cu2+, 80 nm for Ni2+, and 55 nm for Cd2+. This ion‐dependent redshift in the visible region allows the selective detection of these three transition‐metal ions by the naked eye. Studies of reference compounds and IR and NMR spectroscopy revealed that the pyridyl ketone moiety was the metal‐binding site, whereas the carbonyl group on the coumarin moiety did not participate in the metal‐binding process.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Stereoselective Synthesis of Bicyclo[4.2.1]nonanes – a Temporary‐Bridge Approach to Cyclooctanoids
Authors: Michaut Antoine , Miranda‐García Sonia , Menéndez J. Carlos , Coquerel Yoann , Rodriguez Jean 
Published: September 2008

AbstractA series of cis‐α,γ‐difunctionalized five‐membered cyclic β‐oxo esters have been chemo‐, regio‐ and diastereoselectively prepared through an efficient domino anionic ring‐cleavage/ring‐reconstitution/alkylation sequence including a 1,3‐shift of the ester group. These unsaturated substrates were successfully engaged in various ring‐closing metatheses to provide a reliable access to functionalized bicyclo[4.2.1]nonanes, precursors of cyclooctanoids following the selective fragmentation of the one‐carbon bridge.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Using a hidden Markov model to analyse extreme rainfall events in Central‐East Sardinia
Authors: Betrò Bruno , Bodini Antonella , Cossu Q. Antonio 
Published: September 2008

AbstractThe aim of this paper is to investigate the capability of a hidden Markov model (HMM) in identifying possible recurrent patterns in the occurrence of extreme events over a small area of Central‐East Sardinia (Italy), for the purposes of hydrogeological risk prevention. In this area, three intense rainfall events (defined as more than 40 mm in a day) per year are expected during the period September–January. They often assume the characteristics of an extreme event, here defined as more than 100 mm of precipitation in a day. The main interest of modelling daily rainfall data by a HMM lies in the underlying correspondence between the hidden states and the concept of discrete weather states. To model the precipitation at each station, given the weather state, we suggest using a mixture of a point mass at zero and of Weibull distributions, these latter showing a better fit to the considered data than the more usual Gamma and Exponential distributions. Copyright © 2008 John Wiley & Sons, Ltd.
The index rainfall in the regional frequency analysis of extreme events in Tuscany (Italy)
Authors: Caporali Enrica , Cavigli Elisabetta , Petrucci Alessandra 
Published: September 2008

AbstractIn the framework of regional frequency analysis of annual maximum of rainfall depth for short duration storms, the aim of this work is to find expressions of the scale factor of a non‐dimensional regional probability distribution, that is the index rainfall. Over a territory of about 22 000 km2in Tuscany (Italy), the time series of precipitation extreme events of 470 rain gauges, in the period from 1923 to 2002, have been collected and investigated. The Tuscany Region has been divided into three zones and sub‐zones on the basis of a hierarchical regionalization procedure, based on the index rainfall method, and the two‐component extreme value (TCEV) distribution, as the probabilistic model. On the time series, characterized by a low spatial correlation, a local extreme value analysis, based on the generalized extreme value (GEV) distribution, has been also achieved. At the gauge site, the authors introduce the hypotheses that the estimated GEV corresponds to the estimated extreme value of the regional frequency analysis. The index rainfall at the gauge site can be therefore assumed as the ratio of the GEV distribution estimated rainfall and the probabilistic growth factor defined in the hierarchical regionalization procedure. On the basis of the assumption above, a multivariate analysis has been also proposed, with the aim to model the relationship among the spatial variability of index rainfall and the territory characteristics. Copyright © 2008 John Wiley & Sons, Ltd.
A joint association test for multiple SNPs in genetic case‐control studies
Authors: Wang Tao , Jacob Howard , Ghosh Soumitra , Wang Xujing , Zeng Zhao‐Bang 
Published: September 2008

AbstractFor a dense set of genetic markers such as single nucleotide polymorphisms (SNPs) on high linkage disequilibrium within a small candidate region, a haplotype‐based approach for testing association between a disease phenotype and the set of markers is attractive in reducing the data complexity and increasing the statistical power. However, due to unknown status of the underlying disease variant, a comprehensive association test may require consideration of various combinations of the SNPs, which often leads to severe multiple testing problems. In this paper, we propose a latent variable approach to test for association of multiple tightly linked SNPs in case‐control studies. First, we introduce a latent variable into the penetrance model to characterize a putative disease susceptible locus (DSL) that may consist of a marker allele, a haplotype from a subset of the markers, or an allele at a putative locus between the markers. Next, through using of a retrospective likelihood to adjust for the case‐control sampling ascertainment and appropriately handle the Hardy‐Weinberg equilibrium constraint, we develop an expectation‐maximization (EM)‐based algorithm to fit the penetrance model and estimate the joint haplotype frequencies of the DSL and markers simultaneously. With the latent variable to describe a flexible role of the DSL, the likelihood ratio statistic can then provide a joint association test for the set of markers without requiring an adjustment for testing of multiple haplotypes. Our simulation results also reveal that the latent variable approach may have improved power under certain scenarios comparing with classical haplotype association methods.Genet. Epidemiol. 2008. © 2008 Wiley‐Liss, Inc.
The impact of diabetes on employment in Canada
Authors: Latif Ehsan 
Published: September 2008

AbstractThis paper examines the impact of diabetes on the employment of Canadian males and females ages 15–64. Using data from the National Population Health Survey (1998), it utilizes a recursive bivariate probit approach to take into account the potential endogeneity of diabetes in employment outcomes. The results suggest that treating diabetes as exogenous yields an over‐estimation of its impact on male employment. The study finds that diabetes has a significant negative impact on female employment probability, but has no significant impact on that of non‐white Canadians. An implication thus is that policy‐makers should take endogeneity into account in estimating labor market costs of chronic diseases such as diabetes. Copyright © 2008 John Wiley & Sons, Ltd.
New evidence of preference reversals in health utility measurement
Authors: Bleichrodt Han , Pinto Prades Jose Luis 
Published: September 2008

AbstractA central assumption in health utility measurement is that preferences are invariant to the elicitation method used. This assumption is challenged by preference reversals. Previous studies have observed preference reversals between choice and matching tasks and between choice and ranking tasks. We present a preference reversal that is entirely derived from choices, the basic primitive of economics and utility theory. The preference reversal was observed in two studies regarding health states after stroke. Both studies involved large representative samples from the Spanish population, interviewed professionally, and face‐to‐face. Possible explanations for the preference reversal are the anticipation of disappointment and elation in risky choice and the impact of ethical considerations about the value of life. Copyright © 2008 John Wiley & Sons, Ltd.
Prognostic relevance of SOCS3 hypermethylation in patients with glioblastoma multiforme
Authors: Martini Maurizio , Pallini Roberto , Luongo Giuseppe , Cenci Tonia , Lucantoni Corrado , Larocca Luigi Maria 
Published: September 2008

AbstractAlterations in the signal transduction pathways are key mechanisms in the pathogenesis of de novo glioblastoma multiforme (GBM), which are also involved in the resistance to chemo‐ and radiotherapy. Here, we analyzed the methylation status and mRNA expression of suppressor of cytokine signaling (SOCS)1‐2‐3, 3 of the most important inhibitory molecules of the signal transduction circuitry, in 46 GBM specimens. The relationship between methylation status of SOCS1‐2‐3 and clinical outcome was investigated. Using methylation‐specific PCR (MS‐PCR) and sequencing, after bisulphite modification, we found that the promoter of SOCS1‐2‐3 was methylated in 24, 6.5 and 35% of GBM, respectively. Real‐time analysis showed that in methylated GBM, mRNA expression for SOCS1‐2‐3 was reduced by 5, 3 and 7‐folds, respectively, when compared with unmethylated GBM. Moreover, methylation of SOCS3 promoter significantly associated with an unfavorable clinical outcome (p < 0.0002). Our data suggest that methylation of SOCS3 may be involved in the pathogenesis of GBM and in the resistance of this neoplasm to conventional treatment. © 2008 Wiley‐Liss, Inc.
Why do large breast cancers still present in a population offered screening?
Authors: Kricker Anne , Newman Beth , Gertig Dorota M. , Goumas Chris , Armes Jane , Armstrong Bruce K. 
Published: September 2008

AbstractRates of large breast cancers should decrease in a population that is offered mammography screening, but women continue to present with them. We sought an explanation in a population‐based epidemiological study of 1,459 women diagnosed with invasive breast cancer in 2002–2003 in Australia; breast cancers were ≥2 cm in 766 women (53%) and 11–1.9 cm in a comparison group (693, 47%). We interviewed the women about their personal, mammogram and breast histories in the years before diagnosis and collected biological characteristics of tumors and mammogram dates from medical records. The strongest correlate of breast cancer size at diagnosis was the method of detection: the odds of a ≥2 cm breast cancer was substantially lower for detection by a screening mammogram (OR = 0.27, 95% CI 0.21–0.34; p < 0.001) than for detection after a breast symptom. Higher BMI (ORs ∼1.6 for ≥25 kg/m2), higher cancer grade (ORs of 1.6 for moderate, 2.89 for high grade) and lobular type (OR 2.09, 95% CI 1.45–3.0) were also independent correlates (p < 0.001) of a ≥2 cm breast cancer. HRT use strongly reduced the odds but only in cancers detected after a breast symptom (OR = 0.49, 95% CI 0.33–0.74; p = 0.002), not in those detected by a screening mammogram. As assessed from their proportional contribution to ≥2 cm breast cancers in our study population, lack of mammogram detection, BMI ≥25 kg/m2 and moderate or high grade of the cancer were the most important factors with population attributable fractions of 42%, 11% and 29% respectively; the first 2 are amenable to intervention. © 2008 Wiley‐Liss, Inc.