bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Esterase with Superior Activity and Enantioselectivity towards 1,2‐O‐Isopropylideneglycerol Esters Obtained by Protein Design
Authors: Godinho Luis F. , Reis Carlos R. , van Merkerk Ronald , Poelarends Gerrit J. , Quax Wim J. 
Published: November 2012

AbstractThe Escherichia coli esterase YbfF displays high activity towards 1,2‐O‐isopropylideneglycerol (IPG) butyrate and IPG caprylate, and prefers the R‐enantiomer of these substrates, producing the S‐enantiomer of the IPG product in excess. To improve the potential of the enzyme for the kinetic resolution of racemic esters of IPG, an enhancement of the activity and enantioselectivity would be highly desirable. Molecular docking of the R‐enantiomer of both IPG esters into the active site of YbfF allowed the identification of proximal YbfF active site residues. Four residues (25, 124, 185 and 235) were selected as targets for mutagenesis, in order to enhance YbfF activity and enantioselectivity towards IPG esters. Random mutagenesis at positions 25, 124, 185 and 235 yielded several best YbfF variants with enhanced activity and enantioselectivity towards IPG esters. The best YbfF mutant, W235I, exhibited a 2‐fold higher enantioselectivity than wild‐type YbfF, with an E=38 for IPG butyrate and an E=77 for IPG caprylate. Molecular docking experiments further support the enhanced enantioselectivity shown experimentally and the structural effects of this amino acid substitution on the active site of YbfF are provided. The engineered W235I mutant is an attractive catalyst for practical applications in the kinetic resolution of IPG esters.
Transition Metal‐Free α‐C(sp3)H Bond Functionalization of Amines by Oxidative Cross Dehydrogenative Coupling Reaction: Simple and Direct Access to C‐4‐Alkylated 3,4‐Dihydroquinazoline Derivatives
Authors: Kumar R. Arun , Saidulu G. , Prasad K. Rajendra , Kumar G. Sathish , Sridhar B. , Reddy K. Rajender 
Published: November 2012

AbstractA transition metal‐free catalytic system has been developed for the cross dehydrogenative coupling of amines with nitroalkanes under mild condition employing potassium iodide/tert‐butyl hydrogen peroxide catalytic system. This methodology was further extended for the construction of biologically important N‐heterocycles, namely, 3,4‐dihydroquinazoline derivatives. This novel strategy provides a simple, efficient, and direct access to 4‐alkyl‐3,4‐dihydroquinazoline derivatives.
TCF4 (e2‐2; ITF2): A schizophrenia‐associated gene with pleiotropic effects on human disease
Authors: Navarrete Katherinne , Pedroso Inti , De Jong Simone , Stefansson Hreinn , Steinberg Stacy , Stefansson Kari , Ophoff Roel A. , Schalkwyk Leonard C. , Collier David A. 
Published: November 2012

AbstractCommon SNPs in the transcription factor 4 (TCF4; ITF2, E2‐2, SEF‐2) gene, which encodes a basic Helix‐Loop‐Helix (bHLH) transcription factor, are associated with schizophrenia, conferring a small increase in risk. Other common SNPs in the gene are associated with the common eye disorder Fuch's corneal dystrophy, while rare, mostly de novo inactivating mutations cause Pitt‐Hopkins syndrome. In this review, we present a systematic bioinformatics and literature review of the genomics, biological function and interactome of TCF4 in the context of schizophrenia. The TCF4 gene is present in all vertebrates, and although protein length varies, there is high conservation of primary sequence, including the DNA binding domain. Humans have a unique leucine‐rich nuclear export signal. There are two main isoforms (A and B), as well as complex splicing generating many possible N‐terminal amino acid sequences. TCF4 is highly expressed in the brain, where plays a role in neurodevelopment, interacting with class II bHLH transcription factors Math1, HASH1, and neuroD2. The Ca2+ sensor protein calmodulin interacts with the DNA binding domain of TCF4, inhibiting transcriptional activation. It is also the target of microRNAs, including mir137, which is implicated in schizophrenia. The schizophrenia‐associated SNPs are in linkage disequilibrium with common variants within putative DNA regulatory elements, suggesting that regulation of expression may underlie association with schizophrenia. Combined gene co‐expression analyses and curated protein–protein interaction data provide a network involving TCF4 and other putative schizophrenia susceptibility genes. These findings suggest new opportunities for understanding the molecular basis of schizophrenia and other mental disorders. © 2012 Wiley Periodicals, Inc.
Beyond the “central sinus”: radiographic findings in patients undergoing revision functional endoscopic sinus surgery
Authors: Gore Mitchell R. , Ebert Charles S. , Zanation Adam M. , Senior Brent A. 
Published: November 2012

BackgroundFunctional endoscopic sinus surgery (FESS) is widely used by otolaryngologists to treat chronic rhinosinusitis (CRS). The sinonasal anatomy and pathology found in patients with CRS varies widely, as does the FESS technique practiced by otolaryngologists. Variations in the completeness of cell group dissection, combined with the technical challenge of angled endoscopy, result in a wide variation of the post‐FESS cavities harboring persistent disease. The purpose of this study was to identify previously incompletely dissected anatomic structures associated with mucosal thickening found in patients undergoing revision FESS for persistent or recurrent CRS.MethodsRetrospective review of axial, coronal, and sagittal computed tomography (CT) scans of patients undergoing revision FESS by 3 fellowship‐trained rhinologists at a tertiary referral center.ResultsThe CT scans of 55 patients undergoing revision FESS were reviewed. The most frequent radiographic findings were residual anterior and posterior ethmoid cells or septations, found in 65% of sides and 75% of patients. In addition, residual anterior ethmoid agger nasi cells, unopened sphenoid, and residual uncinates were found in 52%, 51%, and 46% of sides, respectively. A large percentage of the patients demonstrated residual ethmoid cells present on the lamina papyracea and skull base, with a lower number found posterior to the middle turbinate basal lamella. A greater number of residual right‐sided vs left‐sided ethmoid cells was noted, with the difference being significant (p < 0.05) at the skull base.ConclusionAnalysis of CT scans of patients undergoing revision FESS for persistent or recurrent CRS frequently reveals persistent anatomical structures or incompletely resected cells associated with persistent mucosal thickening. Meticulous, complete cell group dissection combined with use of angled endoscopy along with identification of possible predisposing structures may aid in the reduction of need for revision surgery.
Dynamic rheological behavior and mechanical properties of PVC/CPE/MAP–POSS nanocomposites
Authors: Du Yonggang , Gao Jungang , Yang Jianbo , Liu Xiaoqian 
Published: November 2012

AbstractPoly(vinyl chloride)/chlorinated polyethylene (PVC/CPE)/methylacryloylpropyl‐containing polyhedral oligomeric silsesquioxane (MAP–POSS) nanocomposites are prepared. The plastic behavior and dynamic rheological behavior of PVC/CPE/MAP–POSS are investigated. The influences of composition on dynamic storage modulus G′, loss modulus G″, and complex viscosity η* of PVC/CPE/MAP–POSS melts are discussed. The dynamic mechanical properties, mechanical properties, and morphology are determined. The results show that both plastic time and balance torque of the nanocomposites decrease, but the G′, G″, and η* all increase with increasing MAP–POSS content. The maximum value of the dynamic mechanical loss tan δ decreases and elasticity increases when MAP–POSS is added. The impact strength of the nanocomposites increases with increasing MAP–POSS content and has the best value at 10% content of MAP–POSS, which is 5.38 kJ/m2 higher than that of the blend without MAP–POSS. The MAP–POSS can be used as an efficient process aid and impact aid for the PVC/CPE blend. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of flavonoid laurate esters by transesterification
Authors: Bridson James H. , Grigsby Warren J. , Main Lyndsay 
Published: November 2012

AbstractLaurate esters of catechin and condensed tannins were synthesized by both transesterification and conventional acylation techniques. Transesterification was developed as an alternative route to prepare flavonoid fatty acid esters as a prerequisite to advancing potential applications. Resorcinol, catechin, and two condensed tannins were transesterified with vinyl esters, and the resulting products were compared to those formed with lauroyl chloride. The esterified products, including catechin pentalaurate, were characterized both chemically and thermally. Transesterification produced partially substituted derivatives, with a preference for substitution at the catechol ring. Melt features were identified at or below 50°C, which were dependent upon the level of substitution. In addition, the tannin laurates showed thermal stability to at least 100°C and moderate retention of antioxidant properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of low viscosity, fast UV curing solder resist based on epoxy resin for ink‐jet printing
Authors: Yang Chao , Yang Zhen‐Guo 
Published: November 2012

AbstractA novel photosensitive low viscosity epoxy resin was synthesized by polyethylene glycol (PEG)‐modified bisphenol‐A epoxy resin (E51). The resin was modified by ethylene glycol, diethylene glycol, and different molecule weights (200,300,400) PEGs to optimize the minimum viscosity. FTIR was used to determine molecule structure. Cationic photoinitiator (UVI‐6976) mixed with modified resin (10 wt %), was utilized to boost the resin curing under UV light. The curing degree was beyond 90% within 40 s and the whole process was monitored by photo‐DSC. The modified resin diluted with ethylene glycol diglycidyl ether, was screen printed onto polyimide and polyethylene terephthalate substrate, and the properties of solder mask were up to China printed circuit association standard. The solder resist also meet all requirements under ink‐jet printing technology as the viscosity is under 60 mPa·s and the curing duration is <1 min. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Insight into the Origin of the Positive Effects of Imidazolium Salt on Electrocatalytic Activity: Ionic Carbon Nanotubes as Metal‐Free Electrocatalysts for Oxygen Reduction Reaction
Authors: Kim Youn Soo , Shin Ju Yeon , Jeon Hyun Ji , Cha Areum , Lee Chongmok , Lee Sang‐gi 
Published: November 2012

AbstractWe report remarkable metal‐free electrocatalytic activities of the imidazolium salt‐functionalized ionic multi‐walled carbon nanotubes (IM‐f‐MWCNTs) in the oxygen reduction reaction (ORR). The electrocatalytic activity can be attributed to the induced polarization of the π‐electrons of CNTs, thus accelerating interfacial electron transfer. The zwitterionic MWCNTs functionalized with poly(vinylimidazolium sulfonate) have a more positive surface charge and exhibit a better electrocatalytic activity than the poly(vinylbutylimidazolium chloride)‐functionalized MWCNTs. The IM‐f‐MWCNTs showed better fuel selectivity than the commercial Pt/C electrocatalyst.
Chemical Synthesis and Enzymatic Testing of CMP‐Sialic Acid Derivatives
Authors: Wolf Saskia , Warnecke Svenja , Ehrit Jörg , Freiberger Friedrich , Gerardy‐Schahn Rita , Meier Chris 
Published: November 2012

AbstractThe cycloSal approach has been used in the past for the synthesis of a range of phosphorylated bioconjugates. In those reports, cycloSal nucleotides were allowed to react with different phosphate nucleophiles. With glycopyranosyl phosphates as nucleophiles, diphosphate‐linked sugar nucleotides were formed. Here, cycloSal‐nucleotides were used to prepare monophosphate‐linked sugar nucleotides successfully in high anomeric purity and high chemical yield. The method was successfully used for the synthesis of three nucleotide glycopyranoses as model compounds. The method was then applied to the syntheses of CMP‐N‐acetyl‐neuraminic acids (CMP‐Neu5NAc) and of four derivatives with different modifications at their amino functions (N‐propanoyl, N‐butanoyl, N‐pentanoyl and N‐cyclopropylcarbonyl). The compounds were used for initial enzymatic studies with a bacterial polysialyltransferase (polyST). Surprisingly, the enzyme showed marked differences in terms of utilisation of the four derivatives. The N‐propanoyl, N‐butanoyl, and N‐pentanoyl derivatives were efficiently used in a first transfer with a fluorescently labelled trisialo‐acceptor. However, elongation of the resulting tetrasialo‐acceptors worsened progressively with the size of the N‐acyl chain. The N‐pentanoyl derivative allowed a single transfer, leading to a capped tetramer. The N‐cyclopropylcarbonyl derivative was not transferred.
Total Synthesis of (+)‐trans‐Trikentrin A
Authors: Tébéka Iris R. M. , Longato Giovanna B. , Craveiro Marcus V. , de Carvalho João E. , Ruiz Ana L. T. G. , Silva Luiz F. 
Published: November 2012

AbstractSeveral syntheses have already been reported for cis‐trikentrins and herbindoles, which are indole alkaloids unsubstituted at the C2 and C3 positions that bear a trans‐1,3‐dimethylcyclopentyl unit. Herein, we describe the first asymmetric and stereoselective synthesis of the more challenging trans‐trikentrin A as its naturally occurring isomer. Different approaches were investigated and the strategy of choice was a combination of an enzymatic kinetic resolution and a thallium(III)‐mediated ring contraction. The antiproliferative activities of the natural product and related intermediates have been tested against human tumor cell lines, leading to the discovery of new compounds with potent antitumor activity.
Investigation of Nanoscopic Free Volume and Interfacial Interaction in an Epoxy Resin/Modified Clay Nanocomposite Using Positron Annihilation Spectroscopy
Authors: Patil Pushkar N. , Sudarshan Kathi , Sharma Sandeep K. , Maheshwari Priya , Rath Sangram K. , Patri Manoranjan , Pujari Pradeep K. 
Published: November 2012

AbstractEpoxy/clay nanocomposites are synthesized using clay modified with the organic modifier N,N‐dimethyl benzyl hydrogenated tallow quaternary ammonium salt (Cloisite 10A). The purpose is to investigate the influence of the clay concentration on the nanostructure, mainly on the free‐volume properties and the interfacial interactions, of the epoxy/clay nanocomposite. Nanocomposites having 1, 3, 5 and 7.5 wt. % clay concentrations are prepared using the solvent‐casting method. The dispersion of clay silicate layers and the morphologies of the fractured surfaces in the nanocomposites are studied using X‐ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The observed XRD patterns reveal an exfoliated clay structure in the nanocomposite with the lowest clay concentration (≤1 wt. %). The ortho‐positronium lifetime (τ3), a measure of the free‐volume size, as well as the fractional free volume (fv) are seen to decrease in the nanocomposites as compared to pristine epoxy. The intensity of free positron annihilation (I2), an index of the epoxy–clay interaction, decreases with the addition of clay (1 wt. %) but increases linearly at higher clay concentrations. Positron age‐momentum correlation measurements are also carried out to elucidate the positron/positronium states in pristine epoxy and in the nanocomposites. The results suggest that in the case of the nanocomposite with the studied lowest clay concentration (1 wt. %), free positrons are primarily localized in the epoxy–clay interfaces, whereas at higher clay concentrations, annihilation takes place from the intercalated clay layers.
Reciprocating Motion of a Self‐Propelled Object on a Molecular Layer
Authors: Nakata Satoshi , Miyaji Tatsuya , Sato Taisuke , Hoshikawa Miho , Ikura Yumihiko S. , Izumi Shunsuke 
Published: November 2012

AbstractThe mode change of a simple autonomous motor depending on the nature of a monolayer on water is investigated. A camphor disk is floated on a molecular layer of N‐stearoyl‐p‐nitroaniline (C18ANA), which gives a surface‐pressure (π)–area per molecule (A) isotherm with a local maximum and a local minimum. The nature of the camphor motion changes depending on A, and in particular, reciprocating motion is observed at a lower A while cutting out its own trajectory of motion. The characteristic motion of a camphor disk depending on A is discussed in relation to the π–A isotherm of C18ANA and the influence of the molecular interaction between molecules on the driving force of motion.
Thermally Induced Release of Internal Liquid Phase Encapsulated in a Polymer Membrane Grown by Photoactivated DLICVD
Authors: Manole Claudiu Constantin , Maury Francis , Demetrescu Ioana 
Published: November 2012

AbstractAn encapsulation of a liquid phase in a thin poly(methyl methacrylate) (PMMA) membrane is achieved in one step by pulsed direct liquid injection (DLI)CVD. The polymer thin film is grown by photo‐activation of the gas phase. An original step of the process, described as thermally induced release of internal liquid phase, permits control of the encapsulated liquid during the CVD polymerization. This step highlights a phenomenon that facilitates a conversion of thermal energy into mechanical energy at the nanometer scale. The experimental results are consistent with biomimetic phenomena as biopolymer membranes of living systems, which show how nature makes an efficient use of miniaturization and temperature gradient.
A Comparative Study of Various Supported Catalysts on the Growth of Aligned Carbon Nanotube Forests on Aluminum Foils
Authors: Ummethala Raghunandan , Khavrus Vyacheslav O. , Leonhardt Albrecht , Büchner Bernd , Eckert Jürgen 
Published: November 2012

AbstractThe influence of a variety of supported catalyst combinations, Fe/Al2O3, Co/Al2O3, Ni/Al2O3, Fe/MnO, Co/MnO, and Ni/MnO, on the growth morphology of carbon nanotubes (CNTs) on aluminum foils is studied. CNT arrays are synthesized by thermal CVD at 645 °C using acetylene as the precursor. The morphology and distribution of the synthesized CNT arrays are analyzed by scanning electron microscopy (SEM). The chemical constitution of each combined catalyst is determined by performing X‐ray diffraction (XRD) investigations on the decomposed and reduced catalysts. Thermodynamic calculations are performed to understand the correlation between the chemical state of the catalyst particles on the substrate and the morphology of the resulting nanotube arrays.
Ethanol pre‐exposure during adolescence or adulthood increases ethanol intake but ethanol‐induced conditioned place preference is enhanced only when pre‐exposure occurs in adolescence
Authors: Carrara‐Nascimento Priscila Fernandes , Olive M. Foster , Camarini Rosana 
Published: November 2012

AbstractBehavioral sensitization has been suggested to contribute to uncontrolled alcohol consumption. The aim of this study was to investigate the effects of repeated ethanol administration in adolescent and adult mice on subsequent ethanol consumption and conditioned place preference (CPP). Mice were administered ethanol for 15 consecutive days. This ethanol regimen induced behavioral sensitization to a lesser degree in adolescents than in adults. Following ethanol treatment, mice were subjected to CPP procedure, or given a free choice between water and ethanol solutions. While ethanol‐pretreated adult mice did not display a robust ethanol‐induced CPP, ethanol induced a significant CPP in mice pretreated with ethanol during adolescence. Ethanol pretreated mice, regardless of age, showed higher ethanol intake to saline‐treated mice. The present findings suggest that ethanol‐induced neuroadaptations underlying behavioral sensitization may activate mechanisms responsible for enhanced ethanol intake, and also reveals that ethanol pre‐exposure during adolescence increases ethanol reward as measured by CPP. © 2012 Wiley Periodicals, Inc. Dev Psychobiol 56: 36–48, 2014.
Subsyndromal delirium in older people: a systematic review of frequency, risk factors, course and outcomes
Authors: Cole Martin G. , Ciampi Antonio , Belzile Eric , Dubuc‐Sarrasin Marika 
Published: November 2012

ObjectiveTo determine the frequency, risk factors, course and outcomes of subsyndromal delirium (SSD) in older people by systematically reviewing evidence on these topics.MethodsSubsyndromal delirium was defined as the presence of one or more symptoms of delirium, not meeting criteria for delirium and not progressing to delirium. MEDLINE, EMBASE, PsycINFO and the Web of Science were searched for potentially relevant articles published from 1996 to June 2011. The bibliographies of relevant articles were searched for additional references. Twelve studies met the inclusion criteria. The validity of included studies was assessed according to Evidence‐Based Medicine criteria. Information about the study population and methods, age, gender, proportion with dementia, diagnostic criteria, period and frequency of observation, and the topics above was systematically abstracted, tabulated and synthesized using standard meta‐analysis techniques.ResultsThe combined prevalence of SSD was 23% (95% CI, 9–42%); the combined incidence was 13% (95% CI, 6–23%). Risk factors were similar to those for delirium. Episodes lasted up to 133 days and were often recurrent. Outcomes were poor and often intermediate between those of older people with or without delirium. Of note, there was significant unexplained heterogeneity in the results of studies of prevalence, incidence and some risk factors.ConclusionsSSD in older people may be a frequent and clinically important condition that falls on a continuum between no symptoms and full delirium. Because of significant unexplained heterogeneity in the results of studies of SSD, however, the results of this review must be interpreted cautiously. Further research is necessary. Copyright © 2012 John Wiley & Sons, Ltd.
Phosphodiesterases in neurodegenerative disorders
Authors: Bollen Eva , Prickaerts Jos 
Published: November 2012

AbstractCyclic nucleotide phosphodiesterases (PDEs) are responsible for the breakdown of cyclic nucleotides, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). As such, they are crucial regulators of levels of cyclic nucleotide‐mediated signaling. cAMP signaling and cGMP signaling have been associated with neuroplasticity and protection, and influencing their levels in the cell by inhibition of PDEs has become a much studied target for treatment in a wide array of disorders, including neurodegenerative disorders. In this review, we will focus on the involvement of PDEs in neurodegenerative disorders. In comparison with preclinical work, data on human patients are scarce. Alzheimer's disease is associated with changes in PDE4, PDE7, and PDE8 expression in the brain. Altered functioning of PDE4 as well as PDE11 is associated with major depressive disorder. In multiple sclerosis, there are indications of alterations in expression of several PDE subtypes in the central nervous system; however, evidence is indirect. In Huntington's disease and Parkinson's disease, most research has focused on PDE1B and PDE10, because of their abundant presence in striatal neurons. In another rare, neurodegenerative striatal motor disorder, that is, autosomal‐dominant striatal degeneration, genetic defects in PDE8B gene are thought to underlie the neurodegenerative processes. Although the latter disorder has showed a causative dysfunction of PDEs, this does not hold for the neurodegenerative disorders discussed above, in which changes in PDE levels seemingly rather represent secondary changes and compensation to prior existing dysfunction. However, normalizing cyclic nucleotide signaling via PDE inhibition remains interesting for the treatment of neurodegenerative disorders. © 2012 IUBMB IUBMB Life, 64(12): 965–970, 2012