bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biopolymere als vielseitige Ressource für die Nanochemie
Authors: Schnepp Zoe 
Published: December 2012

AbstractBiologisches Material ist eine ergiebige Quelle für chemisch vielfältige Makromoleküle wie Polysaccharide, Polypeptide und polyaromatische Verbindungen. Viele dieser biologischen Polymere (Biopolymere) sind auf spezifische Funktionen hin evolutionär optimiert, z. B. über die Molekülkettenlänge, die Funktionalisierung und die Monomersequenz. Gegenwärtig werden zahlreiche Anstrengungen unternommen, die sich auf den chemischen Aufschluss von Biopolymeren für die Verwendung als Treibstoff oder als Ausgangsverbindungen für die Synthese richten. Darüber hinaus gibt es ein steigendes Interesse an der unmittelbaren Verwendung von Biopolymeren für die Herstellung funktioneller Materialien. Dieser Kurzaufsatz zieht Beispiele aus der jüngeren Vergangenheit heran, um aufzuzeigen, wie Biopolymere neue Wege für die Synthese nanostrukturierter Materialien eröffnen können.
Biopolymers as a Flexible Resource for Nanochemistry
Authors: Schnepp Zoe 
Published: December 2012

AbstractBiomass is an abundant source of chemically diverse macromolecules, including polysaccharides, polypeptides, and polyaromatics. Many of these biological polymers (biopolymers) are highly evolved for specific functions through optimized chain length, functionalization, and monomer sequence. As biopolymers are a chemical resource, much current effort is focused on the breakdown of these molecules into fuels or platform chemicals. However there is growing interest in using biopolymers directly to create functional materials. This Minireview uses recent examples to show how biopolymers are providing new directions in the synthesis of nanostructured materials.
CFD analysis to study the effect of design variables on the particle cut size in hydrocyclones
Authors: Delgadillo J. A. , Rosales‐Marin G. , Perez‐Alonso C. , Ojeda C. 
Published: December 2012

ABSTRACTThe modification of hydrocyclone geometry changes the dynamics of the flow, so the particle cut size is affected. Computational fluid dynamics was applied to predict particle classification according to size. Fluent code was used to perform computer simulations for five different hydrocyclone geometries using large eddy simulation and volume of fluid models. The sensitivity to computed modifications in particle classification was evaluated by changing basic design variables, such as spigot diameter, vortex finder diameter, and cone angle. The results show that the particle cut size can be predicted for changes in geometric configuration for a wide range of slurry concentration with a small degree of error using computational fluid dynamics. The error can be attributed to the absence of particle–particle and fluid–particle interaction modeling. However, this assumption is known to be valid only for diluted slurries and some regions within the hydrocyclone. As soon as the particles enter the system, most of them are located within the walls, creating diluted slurry conditions in the main core of the hydrocyclone. The computed results for more concentrated slurries were therefore close to the experimental cut‐size values. In all cases, the particle cut size was predicted successfully. Therefore, the evaluation of changes in the standard geometry to manipulate the dynamics and achieve the desired particle cut size becomes possible. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.
Multicolor electrochromism of low‐bandgap copolymers based on pyrrole and 3,4‐ethylenedioxythiophene: Fine‐tuning colors through feed ratio
Authors: Zhao‐yang Zhang , Yi‐jie Tao , Xiao‐qian Xu , Yong‐jiang Zhou , Hai‐feng Cheng , Wen‐wei Zheng 
Published: December 2012

AbstractThe copolymerization of pyrrole with 3,4‐ethylenedioxythiophene (EDOT) is successfully achieved in boron trifluoride diethyl etherate via direct anodic oxidation of the monomer mixtures on indium‐tin oxide working electrodes. The resultant copolymers are characterized by electrochemical methods, FT‐IR, XPS, SEM, and spectroelectrochemical analysis. The copolymer films present excellent electrochromic properties especially the multicolor electrochromism which can be tuned through the feed ratio of pyrrole and EDOT. The neutral copolymer films exhibit blue‐shift with the increasing feed ratio of pyrrole and EDOT, and the calculated band gaps of the copolymers are as low as that of PEDOT film. Furthermore, the electrochemical and optical stability has been improved by the incorporation of EDOT units into the polymer chains. The copolymer prepared with the changing feed ratio of pyrrole and EDOT at 1/4 retains 71% of its original electroactivity after 500 cycles and 72% of its optical contrast after 500 steps. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Film‐forming behavior and mechanical properties of colloidal silica/polymer latex blends with high silica load
Authors: Yang Ling , Zhou Shuxue , Gu Guangxin , Wu Limin 
Published: December 2012

AbstractIn this article, silica sol (diameter: 8–100 nm) and polymer latex (Tg < 25°C) were mixed and dried at room temperature to prepare nanocomposite films with high silica load (≥50 wt %). Effects of silica size, silica load, and the Tg of the polymer on the film‐forming behavior of the silica/polymer latex blend were investigated. The transparency, morphology, and mechanical properties of the nanocomposite films were examined by UV–Vis spectroscopy, SEM, and nanoindentation tests, respectively. Transparent and crack‐free films were produced with silica loads as high as 70 wt %. Thirty nanometers was found to be the critical silica size for the evolution of film‐forming behavior, surface morphology, and mechanical properties. Colloidal silica particles smaller than this critical size act as binders to form strong silica skeleton. This gives the final silica/polymer nanocomposite film its porous surface and high mechanical strength. However, silica particles with sizes of 30 nm or larger tend to work as nanofillers rather than binders, causing poor mechanical strength. We also determined the critical silica load appeared for the mechanical strength of silica/polymer film at high silica load. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Development of olive oil based organogels using sorbitan monopalmitate and sorbitan monostearate: A comparative study
Authors: Shah Dipak K. , Sagiri Sai S. , Behera B. , Pal Kunal , Pramanik Krishna 
Published: December 2012

AbstractThe present work deals with preparation of the olive oil (OO) based organogels using sorbitan monostearate (SMS) and sorbitan monopalmitate (SMP) as organogelators for controlled drug delivery applications. Metronidazole (MZ) was used as the model drug. Gels were prepared by solubilizing the organogelators in OO at 60°C under stirring. As the solution was cooled down, the gelator molecules precipitate as an isotropic phase having networked structures, which immobilized OO. Formation of 3D networked structure was confirmed by light, phase contrast, and scanning electron microscopy. Accelerated thermal stability studies demonstrated the thermal stability and thermoreversibility of the organogels. DSC and gel disintegration studies suggested that the SMS based organogels were having higher thermal and physical strength as compared to the SMP based organogels. Viscometric analysis suggested the pseudoplastic flow behavior of the gels. The SMS organogels were more amorphous as compared to the SMP organogels of same composition. Drug release from the organogels followed Fickian diffusion kinetics. The drug loaded gels have shown good antimicrobial property against Escherichia coli and Bacillus subtilis and were found to be highly hemocompatible in nature. On the basis of the preliminary results, the developed organogels can be used as matrices for the topical drug delivery. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
A process for preparing polyethylene wax microspheres and optimization of their dissolution precipitation by response surface methodology
Authors: Jia Yin‐yin , Zhang Long 
Published: December 2012

AbstractPolyethylene wax (PEW) microspheres were prepared by the dissolution precipitation method using a PEW byproduct as the starting material. The influence of surfactant type on the morphology and melting point of the product was investigated. The effects of each factor, including the concentration of anionic surfactants, cooling rate, and stirring rate, on the particle sizes were studied using a three‐level, three‐factor Box–Behnken design. The experimental parameters were optimized using response surface methodology. The melting point was found to increase when the blend surfactant was employed. The optimal conditions were an anionic surfactant concentration, cooling rate, and stirring rate of 1.0–3.5%, 1.00 °C/s and 1000 rpm, respectively. Under these conditions, the mean particle size was 15 μm, and the highest yield was 94.25%. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Novel preparation method for enhancing nanoparticle dispersion and barrier properties of poly(ethylene terephthalate) and poly(m‐xylylene adipamide)
Authors: Wang Yin , Jabarin Saleh A. 
Published: December 2012

AbstractA modified melt blending method has been developed for preparing exfoliated nanocomposites of poly(ethylene terephthalate) with sodium‐montmorillonite (Na‐MMT) and poly(m‐xylylene adipamide) with Na‐MMT. In this novel compounding process, a Na‐MMT water solution was blended with the polymer in a twin screw extruder. This mixing process ensured that the silica nanoparticles were exfoliated in the polymer matrix through fixing the nanoparticles within the polymer matrix almost as they were in water. Transmission electron microscopy (TEM) and X‐ray diffraction were used to determine nanoparticle dispersion level. The absence of the X‐ray basal reflections in conjunction with the TEM images revealed the exfoliation of clay platelets. Differential scanning calorimetry illustrated that the nucleating abilities of montmorillonite were related to clay content and dispersion morphology. Oxygen permeation results indicated that the improved morphologies had enhanced the barrier properties of the nanocomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Loss of methylation in CpG sites in the NF‐κB enhancer elements of inducible nitric oxide synthase is responsible for gene induction in human articular chondrocytes
Authors: de Andrés María C. , Imagawa Kei , Hashimoto Ko , Gonzalez Antonio , Roach Helmtrud I. , Goldring Mary B. , Oreffo Richard O. C. 
Published: December 2012

AbstractObjectiveTo investigate whether the abnormal expression of inducible nitric oxide synthase (iNOS) by osteoarthritic (OA) human chondrocytes is associated with changes in the DNA methylation status in the promoter and/or enhancer elements of iNOS.MethodsExpression of iNOS was quantified by quantitative reverse transcriptase–polymerase chain reaction. The DNA methylation status of the iNOS promoter and enhancer regions was determined by bisulfite sequencing or pyrosequencing. The effect of CpG methylation on iNOS promoter and enhancer activities was determined using a CpG‐free luciferase vector and a CpG methyltransferase. Cotransfections with expression vectors encoding NF‐κB subunits were carried out to analyze iNOS promoter and enhancer activities in response to changes in methylation status.ResultsThe 1,000‐bp iNOS promoter has only 7 CpG sites, 6 of which were highly methylated in both control and OA samples. The CpG site at −289 and the sites in the starting coding region were largely unmethylated in both groups. The NF‐κB enhancer region at −5.8 kb was significantly demethylated in OA samples compared with control samples. This enhancer element was transactivated by cotransfection with the NF‐κB subunit p65, alone or together with p50. Critically, methylation treatment of the iNOS enhancer element significantly decreased its activity in a reporter assay.ConclusionThese findings demonstrate the association between demethylation of specific NF‐κB–responsive enhancer elements and the activation of iNOS transactivation in human OA chondrocytes, consistent with the differences in methylation status observed in vivo in normal and human OA cartilage and, importantly, show association with the OA process.
Hearing loss in Muckle‐Wells syndrome
Authors: Kuemmerle‐Deschner Jasmin B. , Koitschev Assen , Ummenhofer Katharina , Hansmann Sandra , Plontke Stefan K. , Koitschev Christiane , Koetter Ina , Angermair Eva , Benseler Susanne M. 
Published: December 2012

AbstractObjectiveMuckle‐Wells syndrome (MWS) is an inherited autoinflammatory disease characterized by fevers, rashes, arthralgia, conjunctivitis, and sensorineural hearing loss. In MWS, NLRP3 gene mutations are associated with excessive interleukin‐1 release. The aims of this study were to determine the otologic characteristics of MWS, define trajectories of hearing loss, and explore the association with distinct NLRP3 genotypes.MethodsA prospective observational cohort study of children and adults diagnosed as having MWS was conducted at a single center. NLRP3 gene mutations were determined. Patients underwent standardized clinical, laboratory, and otologic assessments, including pure tone audiometry, vestibular organ testing, and tinnitus evaluation. Trajectories of hearing loss were defined for each genotype. The genotype‐specific risk of progression of hearing loss was determined.ResultsA total of 33 patients ages 3–75 years who were members of 5 families with 4 different NLRP3 gene mutations were included. The majority of patients (67%) experienced bilateral sensorineural hearing loss. Even in cases of profound hearing loss vestibular reactivity remained normal. Fourteen adult patients reported nondebilitating tinnitus. Overall, hearing impairment progressed with age. Patients with the T348M mutation were at highest risk of rapid progression of sensorineural hearing loss.ConclusionPatients with MWS are at risk of developing progressive sensorineural hearing loss without vestibular involvement. Hearing impairment starts at high frequencies and can subsequently progress to profound hearing loss. Progression is age dependent. Patients with different NLRP3 mutations had distinctly different trajectories of hearing loss, suggesting a mutation‐specific risk that should be considered when making treatment decisions.
3,14‐Bis(p‐nitrophenyl)‐17,17‐dipentyltetrabenzo[a,c,g,i]‐fluorene: A New Fluorophore Displaying Both Remarkable Solvatochromism and Crystalline‐Induced Emission
Authors: Ueda Yoshiaki , Tanigawa Yusuke , Kitamura Chitoshi , Ikeda Hiroshi , Yoshimoto Yuichi , Tanaka Mirai , Mizuno Kazuhiko , Kurata Hiroyuki , Kawase Takeshi 
Published: December 2012

AbstractA series of 17,17‐dialkyl‐3,14‐diaryltetrabenzofluorenes were efficiently prepared by using Suzuki–Miyaura cross‐coupling reactions of the corresponding 3,14‐dibromo derivatives. Studies of the unique fluorescence properties of these compounds showed that they display intense blue to yellow fluorescence with high quantum yields in the solution state and blue to orange fluorescence with moderate quantum yields in the solid state. In addition, the fluorescence wavelength of the bis(p‐nitrophenyl) derivative is remarkably solvent‐dependent in a manner that correlates with the solvent polarity parameter ET(30). The results of density function theory calculations suggest that the intramolecular charge‐transfer character of the HOMO–LUMO transition is responsible for the large solvent effect. Moreover, addition of water to a tetrahydrofuran (THF) solution of this compound leads to quenching of the yellow fluorescence owing to an increase in the solvent polarity. However, when the amount of water fraction exceeds 70 %, a new fluorescence band appears at the same orange‐red emission wavelength as that of the solid‐state fluorescence. This observation suggests the occurrence of a crystallization‐induced emission (CIE) phenomenon in highly aqueous THF.
Stereocontrolled Organocatalytic Strategy for the Synthesis of Optically Active 2,3‐Disubstituted cis‐2,3‐Dihydrobenzofurans
Authors: Christensen Jannie , Albrecht Łukasz , Jørgensen Karl Anker 
Published: December 2012

AbstractAn intramolecular, organocatalyzed Michael addition has been developed to obtain biologically important 2,3‐disubstituted cis‐2,3‐dihydrobenzofurans. By using mandelic acid salts of primary aminocatalysts, derived from cinchona alkaloids, the intramolecular cyclization reaction has been developed to proceed in high yield, with moderate to good diastereoselectivity, and up to 99 % ee. Based on the absolute configuration of the formed 2,3‐disubstituted‐cis‐2,3‐dihydrobenzofurans and by considering the observed substrate scope restrictions, a mechanistic rationalization has been presented.
Dividends in finite time horizon
Authors: Cardoso Rui M.R. 
Published: December 2012

In this paper, we consider the classical risk model modified in two different ways by the inclusion of a dividend barrier. For Model I, we present numerical algorithms, which can be used to approximate or bound the expected discounted value of dividends up to a finite time horizon, t, or ruin if this occurs earlier. We extend this by requiring the shareholders to provide the initial capital and to pay the deficit at ruin each time it occurs so that the process then continues after ruin up to time t. For Model I, we assume the full premium income is paid as dividends whenever the surplus exceeds a set level.In our Model II, we assume dividends are paid at a rate less than the rate of premium income. Copyright © 2012 John Wiley & Sons, Ltd.
Functional motor recovery is improved due to local placement of GDNF microspheres after delayed nerve repair
Authors: Wood Matthew D. , Gordon Tessa , Kemp Stephen W.P. , Liu Edward H. , Kim Howard , Shoichet Molly S. , Borschel Gregory H. 
Published: December 2012

AbstractThe majority of bioengineering strategies to promote peripheral nerve regeneration after injury have focused on therapies to bridge large nerve defects while fewer therapies are being developed to treat other nerve injuries, such as nerve transection. We constructed delivery systems using fibrin gels containing either free GDNF or polylactide–glycolic acid (PLGA) microspheres with GDNF to treat delayed nerve repair, where ELISA verified GDNF release. We determined the formulation of microspheres containing GDNF that optimized nerve regeneration and functional recovery in a rat model of delayed nerve repair. Experimental groups underwent delayed nerve repair and treatment with GDNF microspheres in fibrin glue at the repair site or control treatments (empty microspheres or free GDNF without microspheres). Contractile muscle force, muscle mass, and MUNE were measured 12 weeks following treatment, where GDNF microspheres (2 weeks formulation) were superior compared to either no GDNF or short‐term release of free GDNF to nerve. Nerve histology distal to the repair site demonstrated increased axon counts and fiber diameters due to GDNF microspheres (2 weeks formulation). GDNF microspheres partially reversed the deleterious effects of chronic nerve injury, and recovery was slightly favored with the 2 weeks formulation compared to the 4 weeks formulation. Biotechnol. Bioeng. 2013; 110: 1272–1281. © 2012 Wiley Periodicals, Inc.
Whole‐cell‐based CYP153A6‐catalyzed (S)‐limonene hydroxylation efficiency depends on host background and profits from monoterpene uptake via AlkL
Authors: Cornelissen Sjef , Julsing Mattijs K. , Volmer Jan , Riechert Ole , Schmid Andreas , Bühler Bruno 
Published: December 2012

AbstractLiving microbial cells are considered to be the catalyst of choice for selective terpene functionalization. However, such processes often suffer from side product formation and poor substrate mass transfer into cells. For the hydroxylation of (S)‐limonene to (S)‐perillyl alcohol by Pseudomonas putida KT2440 (pGEc47ΔB)(pCom8‐PFR1500), containing the cytochrome P450 monooxygenase CYP153A6, the side products perillyl aldehyde and perillic acid constituted up to 26% of the total amount of oxidized terpenes. In this study, it is shown that the reaction rate is substrate‐limited in the two‐liquid phase system used and that host intrinsic dehydrogenases and not CYP153A6 are responsible for the formation of the undesired side products. In contrast to P. putida KT2440, E. coli W3110 was found to catalyze perillyl aldehyde reduction to the alcohol and no oxidation to the acid. Furthermore, E. coli W3110 harboring CYP153A6 showed high limonene hydroxylation activities (7.1 U g). The outer membrane protein AlkL was found to enhance hydroxylation activities of E. coli twofold in aqueous single‐phase and fivefold in two‐liquid phase biotransformations. In the latter system, E. coli harboring CYP153A6 and AlkL produced up to 39.2 mmol (S)‐perillyl alcohol L within 26 h, whereas no perillic acid and minor amounts of perillyl aldehyde (8% of the total products) were formed. In conclusion, undesired perillyl alcohol oxidation was reduced by choosing E. coli's enzymatic background as a reaction environment and co‐expression of the alkL gene in E. coli represents a promising strategy to enhance terpene bioconversion rates. Biotechnol. Bioeng. 2013; 110: 1282–1292. © 2012 Wiley Periodicals, Inc.
Real‐time detection of cellular death receptor‐4 activation by fluorescence resonance energy transfer
Authors: Dereli‐Korkut Zeynep , Gandhok Harmeet , Zeng Ling Ge , Waqas Sidra , Jiang Xuejun , Wang Sihong 
Published: December 2012

AbstractTargeted therapy involving the activation of death receptors DR4 and/or DR5 by its ligand, TRAIL, can selectively induce apoptosis in certain tumor cells. In order to profile the dynamic activation or trimerization of TRAIL–DR4 in live cells in real‐time, the development of an apoptosis reporter cell line is essential. Fluorescence resonance energy transfer (FRET) technology via a FRET pair, cyan fluorescence protein (CFP) and yellow fluorescence protein (YFP), was used in this study. DR4‐CFP and DR4‐YFP were stably expressed in human lung cancer PC9 cells. Flow cytometer sorting and limited dilution coupled with fluorescence microscopy were used to select a monoclonal reporter cell line with high and compatible expression levels of DR4‐CFP and DR4‐YFP. FRET experiments were conducted and FRET efficiencies were monitored according to the Siegel's YFP photobleaching FRET protocol. Upon TRAIL induction a significant increase in FRET efficiencies from 5% to 9% demonstrated the ability of the DR4‐CFP/YFP reporter cell line in monitoring the dynamic activation of TRAIL pathways. 3D reconstructed confocal images of DR4‐CFP/YFP reporter cells exhibited a colocalized expression of DR4‐CFP and DR4‐YFP mainly on cell membranes. FRET results obtained during this study complements the use of epi‐fluorescence microscopy for FRET analysis. The real‐time FRET analysis allows the dynamic profiling of the activation of TRAIL pathways by using the time‐lapse fluorescence microscopy. Therefore, DR4‐CFP/YFP PC9 reporter cells along with FRET technology can be used as a tool for anti‐cancer drug screening to identify compounds that are capable of activating TRAIL pathways. Biotechnol. Bioeng. 2013; 110: 1396–1404. © 2012 Wiley Periodicals, Inc.
Resection margin involvement and tumour origin in pancreatic head cancer (Br J Surg 2012 99 1036–1049)
Authors: Erdmann J , van Eijck C H J 
Published: December 2012

Abstract
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