bluuebunny/crossref_metadata_2025_split huggingface dataset:
Topochemical Synthesis of Cobalt Oxide‐Based Porous Nanostructures for High‐Performance Lithium‐Ion Batteries
Authors: Li Cheng Chao , Yin Xiao Ming , Li Qiu Hong , Chen Li Bao , Wang Tai Hong 
Published: January 2011

AbstractTwo kinds of topochemical conversion routes from cobalt hydroxide precursors to cobalt oxide‐based porous nanostructures are presented: pyrolysis in air and hydrothermal treatment by the Kirkendall diffusion effect. These cobalt hydroxide precursors were synthesized by a simple hydrothermal approach with sodium acetate as mineralizer at 200 °C. Detailed proof indicates that the process of cobalt hydroxide precursor growth is dominated by a nucleation, dissolution, renucleation, growth, and exfoliation mechanism. By the topochemical conversion processes several Co3O4 nanostructures, such as cobalt oxide‐coated cobalt hydroxide carbonate nanowires, cobalt oxide nanotubes, hollow cobalt oxide spheres, and porous cobalt oxide nanowires, have been synthesized. The obtained Co3O4 nanostructures have also been evaluated as the anode materials in lithium‐ion batteries. It was found that the as‐prepared Co3O4 nanostructures exhibited high reversible capacity and good cycle performance due to their porous structure and small size.
Modeling the cis‐Oxo‐Labile Binding Site Motif of Non‐Heme Iron Oxygenases: Water Exchange and Oxidation Reactivity of a Non‐Heme Iron(IV)‐Oxo Compound Bearing a Tripodal Tetradentate Ligand
Authors: Company Anna , Prat Irene , Frisch Jonathan R. , Mas‐Ballesté Dr Ruben , Güell Mireia , Juhász Gergely , Ribas Xavi , Münck Dr Eckard , Luis Josep M. , Que Lawrence , Costas Miquel 
Published: January 2011

AbstractThe spectroscopic and chemical characterization of a new synthetic non‐heme iron(IV)‐oxo species [FeIV(O)(Me,HPytacn)(S)]2+ (2, Me,HPytacn=1‐(2′‐pyridylmethyl)‐4,7‐dimethyl‐1,4,7‐triazacyclononane, S=CH3CN or H2O) is described. Complex 2 was prepared by reaction of [FeII(CF3SO3)2(Me,HPytacn)] (1) with peracetic acid. Complex 2 bears a tetradentate N4 ligand that leaves two cis sites available for binding an oxo group and a second external ligand but, unlike the related iron(IV)‐oxo species with tetradentate ligands, it is remarkably stable at room temperature (t1/2>2 h at 288 K). Its ability to exchange the oxygen atom of the oxo ligand with water has been analyzed in detail by means of kinetic studies, and a mechanism is proposed on the basis of DFT calculations. Hydrogen‐atom abstraction from CH bonds and oxygen‐atom transfer to sulfides by 2 have also been studied. Despite its thermal stability, 2 proves to be a very powerful oxidant that is capable of breaking the strong CH bond of cyclohexane (bond dissociation energy=99.3 kcal mol−1).
Mimicking Photosynthetic Antenna‐Reaction‐Center Complexes with a (Boron Dipyrromethene)3–Porphyrin–C60 Pentad
Authors: Liu Jian‐Yong , El‐Khouly Mohamed E. , Fukuzumi Shunichi , Ng Dennis K. P. 
Published: January 2011

AbstractA highly efficient functional mimic of the photosynthetic antenna‐reaction‐center complexes has been designed and synthesized. The model contains a zinc(II) porphyrin (ZnP) core, which is connected to three boron dipyrromethene (BDP) units by click chemistry, and to a C60 moiety using the Prato procedure. The compound has been characterized using various spectroscopic methods. The intramolecular photoinduced processes of this pentad have also been studied in detail with steady‐state and time‐resolved absorption and emission spectroscopic methods, both in polar benzonitrile and nonpolar toluene. The BDP units serve as the antennae, which upon excitation undergo singlet–singlet energy transfer to the porphyrin core. This is then followed by an efficient electron transfer to the C60 moiety, resulting in the formation of the singlet charge‐separated state (BDP)3–ZnP.+–C60.−, which has a lifetime of 476 and 1000 ps in benzonitrile and toluene, respectively. Interestingly, a slow charge‐recombination process (${k{{{\rm T}\hfill \atop {\rm CR}\hfill}}}$=2.6×106 s−1) and a long‐lived triplet charge‐separated state (${\tau {{{\rm T}\hfill \atop {\rm CS}\hfill}}}$=385 ns) were detected in polar benzonitrile by nanosecond transient measurements.
Selectivity among Two Lectins: Probing the Effect of Topology, Multivalency and Flexibility of “Clicked” Multivalent Glycoclusters
Authors: Cecioni Samy , Faure Sophie , Darbost Ulrich , Bonnamour Isabelle , Parrot‐Lopez Hélène , Roy Olivier , Taillefumier Claude , Wimmerová Michaela , Praly Jean‐Pierre , Imberty Anne , Vidal Sébastien 
Published: January 2011

AbstractThe design of multivalent glycoconjugates has been developed over the past decades to obtain high‐affinity ligands for lectin receptors. While multivalency frequently increases the affinity of a ligand for its lectin through the so‐called “glycoside cluster effect”, the binding profiles towards different lectins have been much less investigated. We have designed a series of multivalent galactosylated glycoconjugates and studied their binding properties towards two lectins, from plant and bacterial origins, to determine their potential selectivity. The synthesis was achieved through copper(I)‐catalysed azide–alkyne cycloaddition (CuAAC) under microwave activation between propargylated multivalent scaffolds and an azido‐functionalised carbohydrate derivative. The interactions of two galactose‐binding lectins from Pseudomonas aeruginosa (PA‐IL) and Erythrina cristagalli (ECA) with the synthesized glycoclusters were studied by hemagglutination inhibition assays (HIA), surface plasmon resonance (SPR) and isothermal titration microcalorimetry (ITC). The results obtained illustrate the influence of the scaffold’s geometry on the affinity towards the lectin and also on the relative potency in comparison with a monovalent galactoside reference probe.
Vapor‐ and Mechanical‐Grinding‐Triggered Color and Luminescence Switches for Bis(σ‐fluorophenylacetylide) Platinum(II) Complexes
Authors: Ni Jun , Zhang Xu , Wu Yu‐Hui , Zhang Li‐Yi , Chen Zhong‐Ning 
Published: January 2011

AbstractSquare‐planar bis(σ‐fluorophenylacetylide) platinum(II) complexes [Pt(Me3SiCCbpyCC‐SiMe3)(CCC6H4F)2] (CCC6H4F‐2 for 2, CCC6H4F‐3 for 3, and CCC6H4F‐4 for 4; Me3SiCCbpyCCSiMe3=5,5′‐bis(trimethylsilylethynyl)‐2,2′‐bipyridine) were prepared and were characterized by spectroscopic and luminescence studies, and X‐ray crystallography. The color and luminescence of crystalline complex 3 is specifically sensitive to CHCl3 vapor to afford 140–180 nm of luminescence vapochromic redshift, which is useful for specific detection of CHCl3 vapor. Complex 4 displays selective luminescence vapochromic properties to CH2Cl2 and CHCl3 vapors with a luminescence vapochromic shift response of ca. 150–200 nm. Interestingly, complexes 2–4 exhibit reversible, and naked‐eye perceivable, mechanical stimuli‐responsive color and luminescence changes. When solid species 2–4 are crushed gently or ground, the crystalline state is converted to an amorphous phase. Meanwhile, bright yellow‐orange luminescence in the crystalline species is converted to dark red under UV light irradiation with 100–160 nm of mechanochromic shift response. A vapochromic or mechanochromic cycle was monitored by dynamic variations in emission spectra and X‐ray diffraction (XRD) patterns. The halohydrocarbon vapor‐ or mechanical‐grinding‐triggered color and luminescence switches are most likely correlated to a shorted intermolecular Pt–Pt distance as that revealed in vapochromic species 4⋅0.5 CH2Cl2 by X‐ray crystallography, thus leading to an increased contribution from intermolecular Pt–Pt interaction as demonstrated by DTF computational studies.
Bioactive natural products and chirality
Authors: Mori Kenji 
Published: January 2011

AbstractMori's synthetic works on bioactive natural products in general and pheromones in particular started about 40 years ago to establish their absolute configurations and also to clarify their stereochemistry–bioactivity relationships. Results indicate that bioactive natural products are not always enantiomerically pure, and the stereochemistry–bioactivity relationships are not simple but complicated. For example, neither (R)‐ nor (S)‐sulcatol, the aggregation pheromone of an ambrosia beetle, is behaviorally bioactive, whereas their mixture is active. In the case of olean, the sex pheromone of the olive fruit fly, its (R)‐isomer is active against the males and the (S)‐isomer is active against the females. Recent synthesis of two new insect pheromones is discussed to illustrate the modern methods in enantioselective synthesis. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
The search for a deterministic origin for the presence of nonracemic amino‐acids in meteorites: A computational approach
Authors: Vandenbussche Sophie , Reisse Jacques , Bartik Kristin , Lievin Jacques 
Published: January 2011

AbstractAmino‐acid enantiomeric excesses (ee's) have been detected in different types of carbonaceous chondrites, all in favor of the L enantiomer. In this article, we discuss possible deterministic causes to the presence of these amino‐acid ee's in meteorites and evaluate in particular enantioselective photolysis by circularly polarized light (CPL). The electronic circular dichroism spectra of a set of amino‐ and hydroxy‐acids, all detected in chondritic matter but some with ee's and others without ee's, were calculated and compared. The spectra were calculated for the most stable conformation(s) of the considered molecules using quantum mechanical methods (density functional theory). Our results suggest that CPL photolysis in the gas phase was perhaps not at the origin of the presence of ee's in meteorites and that the search for another, but still unknown, deterministic cause must be seriously undertaken. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Chiral separation of D,L‐mandelic acid through cellulose membranes
Authors: Ma Chao , Xu Xiao‐Lin , Ai Ping , Xie Sheng‐Ming , Lv Ying‐Chun , Shan Hai‐Qin , Yuan Li‐Ming 
Published: January 2011

AbstractThis work reports the chiral separation of D,L‐mandelic acid with cellulose membranes. Cellulose was chosen as membrane material because it possesses multichiral carbon atoms in its molecular structure unit. The flux and permselective properties of membrane using aqueous solutions of D,L‐mandelic acid as feed solution was studied. The top surface and cross‐section morphology of the resulting membrane were examined by scanning electron microscopy. When the membrane was prepared with 8.1 wt % cellulose and 8.1 wt % LiCl in the DMA casting solution, and the operating pressure and feed concentration of racemate were 0.0125 MPa and 0.5 mg/ml, respectively, over 90% of enantiomeric excess could be obtained. This is the first report that the cellulose membrane is used for isolating the optical isomers of D,L‐mandelic acid. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Nitrooxyacyl Derivatives of Salicylic Acid: Aspirin‐Like Molecules that Covalently Inactivate Cyclooxygenase‐1
Authors: Cena Clara , Tosco Paolo , Marini Elisabetta , Lazzarato Loretta , Piccinini Marco , Ramondetti Cristina , Lupino Elisa , Fruttero Roberta , Gasco Alberto 
Published: January 2011

AbstractA recently described series of nitrooxyacyl derivatives of salicylic acid, displaying aspirin‐like anti‐inflammatory and platelet anti‐aggregatory properties, were evaluated for their abilities to inhibit cyclooxygenase (COX). A number of these compounds irreversibly inhibited both COX‐1 and COX‐2 isoforms when tested in isolated human platelets and monocytes. Further studies using COX‐1 expressed in human HEK293T cells showed that this inhibition mechanism is similar to that of aspirin; namely, the products are able to covalently bind to the Ser 530 residue present in the active cleft of the enzyme. Molecular modeling enabled us to rationalize this behavior. Because these products were previously found to display NO‐dependent properties in rat animal models, particularly as they decreased in vivo gastrotoxicity and induced in vitro vasodilation, they represent a new and interesting class of potential aspirin‐like antithrombotic agents worthy of further study.
24‐Hour Fasting with Diabetes: guide to physicians advising patients on medication adjustments prior to religious observances (or outpatient surgical procedures)
Authors: Grajower Martin M. 
Published: January 2011

AbstractPatients with diabetes may undergo an approximately 24‐h fast for a voluntary religious observance or in preparation for a medical procedure. Commonly, patients will manage their diabetes before and during such fasting without guidelines from their doctors, often because they did not ask for advice. The physician should therefore take the lead in advising patients how to fast safely, in order to avoid the situation wherein the patient manages medication changes on his/her own. Furthermore, it sends a message to the patient that having diabetes does not preclude living a reasonably ‘normal’ life, even when it comes to religious observances. Copyright © 2011 John Wiley & Sons, Ltd.
The First Total Synthesis of Topsentolide B3
Authors: Sreedhar Eppakayala , Venkanna Arramshetti , Chandramouli Nagula , Babu K. Suresh , Rao Janaswamy Madhusudana 
Published: January 2011

AbstractThe first total synthesis of the cytotoxic oxylipin Topsentolide B3 has been accomplished in 15 steps with an overall yield of 24 %. Starting with readily available cis‐butene diol as a synthon, the synthesis involved Marouka allylation and Sharpless hydroxylation for the construction of three asymmetric centers. The nine‐membered lactone ring was built through a selective Grubbs ring‐closing metathesis reaction. Other key steps in the synthesis are CuI‐mediated alkynylation and Swern oxidation reactions. This provides a unique approach to the synthesis of oxylipins and offers the advantages of brevity and relatively high overall yield.
2′‐Deoxy‐2′‐α‐C‐(hydroxymethyl)adenosine as Potential anti‐HCV Agent
Authors: Chavain Natascha , Herdewijn Piet 
Published: January 2011

AbstractBecause of the importance of C‐branched nucleosides in the discovery of new antiviral molecules, we decided to synthesize 2′‐deoxy‐2′‐α‐C‐(hydroxymethyl)adenosine as a potential anti‐HCV agent. The synthesis of a new adenosine analogue following two different synthetic routes is described. The new C‐branched nucleoside was tested for its antiviral activity and found to be inactive.
The potential of white‐rot fungi to degrade phorbol esters of Jatropha curcas L. seed cake
Authors: de Barros Cândida R. M. , Ferreira Luis M. M. , Nunes Fernando M. , Bezerra Rui M. F. , Dias Albino A. , Guedes Cristina V. , Cone John W. , Marques Guilhermina S. M. , Rodrigues Miguel A. M. 
Published: January 2011

AbstractThe potential of solid‐state cultivation, with three white‐rot fungi (Bjerkandera adusta, Ganoderma resinaceum and Phlebia rufa), to decrease phorbol esters concentration of Jatropha curcas L. was evaluated in this study. Incubation was conducted in 250 mL Erlenmeyer flasks without agitation at 28°C for 30 days. Phorbol esters were analyzed by reverse‐phase HPLC after an extraction procedure using dichloromethane. All fungi studied were able to decrease the concentration of phorbol esters, mainly B. adusta and P. rufa which significantly reduced (p<0.05) phorbol esters contents to non‐toxic levels. These results suggest that white‐rot fungi could be potentially used as a possible approach for the biological treatment of the oilseed cake.
Assessment of the backflashover occurrence rate on HV transmission line towers
Authors: Sarajcev Petar , Goic Ranko 
Published: January 2011

SUMMARYAn assessment of the backflashover occurrence rate on the high voltage (HV) transmission line towers is presented in this paper. It is based on a mathematical model that accounts for the transmission line geometry, keraunic level, statistical distribution of lightning current parameters, and correlation between statistical variables defining the lightning current waveshape. Furthermore, assessment of the backflashover occurrence rate on these towers accounts for the tower footing impulse resistance, lightning impulse insulation strength of the insulator strings and surge impedance of the tower itself. Proposed theoretical analysis is backed by the most recent propositions of parameters that define statistical distributions of lightning current parameters and then applied to the typical HV transmission line example. This analysis might be useful when scrutinizing the several first transmission line towers incoming to the HV substations. Hence, here presented analysis could be subsequently applied for the design of the HV substation overvoltage protection. Finally, a sensitivity analysis is provided, in regards to the parameters of the log‐normal distributions defining lightning current amplitude and steepness, as well as in regards to the tower footing impulse resistance. Copyright © 2011 John Wiley & Sons, Ltd.
Shape‐memory anchoring system for bladder sensors
Authors: Pereira Iaci M. , Axisa Fabrice , Oréfice Rodrigo L. , Vanfleteren Jan , Neves Hercules P. 
Published: January 2011

AbstractIn this work, we propose the use of shape‐memory polymer as an anchoring system for a bladder sensor. The anchoring system was designed from a biomedical biodegradable water‐based poly(ester‐urethane) produced in an aqueous environment by using isophorone diisocyanate/hydrazine (hard segment) and poly(caprolactone diol)/2,2‐bis (hydroxymethyl) propionic acid (soft segment) as the main reagents. Tensile strength and elongation‐at‐break deterioration upon degradation in synthetic urine were investigated. In‐body shape recovery was simulated and measured in synthetic urine. Results indicated that shape recovery can occur at body temperature and expulsion of the sensor by the body along with urine may occur through the combined effect of urine hydrolytic attack and compression exerted by the bladder walls. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Development, validation, and results of a measure of 30‐day readmission following hospitalization for pneumonia
Authors: Lindenauer Peter K. , Normand Sharon‐Lise T. , Drye Elizabeth E. , Lin Zhenqiu , Goodrich Katherine , Desai Mayur M. , Bratzler Dale W. , O'Donnell Walter J. , Metersky Mark L. , Krumholz Harlan M. 
Published: January 2011

AbstractBACKGROUND:Readmission following hospital discharge has become an important target of quality improvement.OBJECTIVE:To describe the development, validation, and results of a risk‐standardized measure of hospital readmission rates among elderly patients with pneumonia employed in federal quality measurement and efficiency initiatives.DESIGN:A retrospective cohort study using hospital and outpatient Medicare claims from 2005 and 2006.SETTING:A total of 4675 hospitals in the United States.PATIENTS:Medicare beneficiaries aged >65 years with a principal discharge diagnosis of pneumonia.INTERVENTION:None.MEASUREMENTS:Hospital‐specific, risk‐standardized 30‐day readmission rates calculated as the ratio of predicted‐to‐expected readmissions, multiplied by the national unadjusted rate. Comparison of the areas under the receiver operating curve (ROC) and measurement of correlation coefficient in development and validation samples.RESULTS:The development sample consisted of 226,545 hospitalizations at 4675 hospitals, with an overall unadjusted 30‐day readmission rate of 17.4%. The median risk‐standardized hospital readmission rate was 17.3%, and the odds of readmission for a hospital one standard deviation above average was 1.4 times that of a hospital one standard deviation below average. Performance of the medical record and administrative models was similar (areas under the ROC curve 0.59 and 0.63, respectively) and the correlation coefficient of estimated state‐specific standardized readmission rates from the administrative and medical record models was 0.96.CONCLUSIONS:Rehospitalization within 30 days of treatment for pneumonia is common, and rates vary across hospitals. A risk‐standardized measure of hospital readmission rates derived from administrative claims has similar performance characteristics to one based on medical record review. Journal of Hospital Medicine 2010. © 2010 Society of Hospital Medicine
A Model for Flow‐enhanced Nucleation Based on Fibrillar Dormant Precursors
Authors: Roozemond Peter C. , Steenbakkers Rudi J. A. , Peters Gerrit W. M. 
Published: January 2011

AbstractA model for flow‐enhanced nucleation is presented based on the concept of a polymer melt containing a fixed number of nucleation precursors with a fixed size distribution. Depending on the size, precursors can either be active (i.e. susceptible to nucleation, the characteristic time scale of which is governed by the deformation rate) and grow into a spherulite or remain dormant. The size distribution of precursors is derived by combining nucleation theory and experimentally determined quiescent spherulite number densities. Longitudinal precursor growth, causing activation of dormant precursors, is a function of molecular deformation: the stretch of high molecular weight chains. Both the eXtended Pom‐Pom and the Rolie‐Poly model are tested to calculate the molecular deformation. A quantitative agreement is found between simulations and experimental results. magnified image
Complex behavioral and synaptic effects of dietary branched chain amino acids in a mouse model of amyotrophic lateral sclerosis
Authors: Venerosi Aldina , Martire Alberto , Rungi Angela , Pieri Massimo , Ferrante Antonella , Zona Cristina , Popoli Patrizia , Calamandrei Gemma 
Published: January 2011

AbstractScope: We hypothesized that chronic supplementation with branched chain amino acids (BCAAs) affects neurobehavioral development in vulnerable gene backgrounds.Methods and results: A murine model of amyotrophic lateral sclerosis (ALS), G93A mice bearing the mutated human superoxide dismutase 1 (SOD1) gene, and control mice received from 4 to 16 wk of age dietary supplementation with BCAAs at doses comparable to human usage. Motor coordination, exploratory behaviors, pain threshold, synaptic activity and response to glutamatergic stimulation in primary motor cortex slices were evaluated between the 8th and 16th week. The glial glutamate transporter 1 (GLT‐1) and metabotropic glutamate 5 receptor (mGlu5R) were analyzed by immunoblotting in cortex, hippocampus and striatum. BCAAs induced hyperactivity, decreased pain threshold in wild‐type mice and exacerbated the motor deficits of G93A mice while counteracting their abnormal pain response. Electrophysiology on G93A brain slices showed impaired synaptic function, reduced toxicity of GLT‐1 blocking and increased glutamate toxicity prevented by BCAAs. Immunoblotting indicated down‐regulation of GLT‐1 and mGlu5R in G93A, both effects counteracted by BCAAs.Conclusion: These results, though not fully confirming a role of BCAAs in ALS‐like etiology in the genetic model, clearly indicate that BCAAs' complex effects on central nervous system depend on gene background and raise alert over their spread use.