bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐Performance, Low‐Operating‐Voltage Organic Field‐Effect Transistors with Low Pinch‐Off Voltages
Authors: Wu Weiping , Liu Yunqi , Wang Ying , Xi Hongxia , Gao Xike , Di Chongan , Yu Gui , Xu Wei , Zhu Daoben 
Published: February 2008

AbstractOrganic field‐effect transistors suffer from ultra‐high operating voltages in addition to their relative low mobility. A general approach to low‐operating‐voltage organic field‐effect transistors (OFETs) using donor/acceptor buffer layers is demonstrated. P‐type OFETs with acceptor molecule buffer layers show reduced operating voltages (from 60–100 V to 10–20 V), with mobility up to 0.19 cm2 V−1 s−1 and an on/off ratio of 3 × 106. The subthreshold slopes of the devices are greatly reduced from 5–12 V/decade to 1.68–3 V/decade. This favorable combination of properties means that such OFETs can be operated successfully at voltages below 20 V (|VDS| ≤ 20 V, |VGS| ≤ 20 V). This method also works for n‐type semiconductors. The reduced operating voltage and low pinch‐off voltage contribute to the improved ordering of the polycrystalline films, reduced grain boundary resistance, and steeper subthreshold slopes.
Cyclization of Allenyne‐1,6‐diols Catalyzed by Gold and Silver Salts: An Efficient Selective Synthesis of Dihydrofuran and Furan Derivatives
Authors: Kim Sundae , Lee Phil Ho 
Published: February 2008

AbstractTreatment of allenyne‐1,6‐diols with gold and silver catalysts selectively produced 2,5‐dihydrofuran and furan derivatives, respectively, in good to excellent yields through the selective activation and differentiation of the double and triple bonds in allenyne‐1,6‐diols. It is noteworthy that the chemoselectivity is clearly switched by simply changing the metal from gold to silver.
Rationally‐Designed S‐Chiral Bissulfinamides as Highly Enantioselective Organocatalysts for Reduction of Ketimines
Authors: Pei Dong , Zhang Yu , Wei Siyu , Wang Meng , Sun Jian 
Published: February 2008

AbstractWe recently reported the first example of S‐chiral organocatalysts, that are highly efficient and enantioselective in substoichometric amounts, and which use a chiral monosulfinamide group as Lewis base to activate trichlorosilane (HSiCl3) to reduce N‐arylketimines. A plausible mechanism involving two molecules of the monosulfinamde catalyst for the activation of HSiCl3 prompted us to design S‐chiral bissulfinamides as new catalysts. We herein describe our findings that an easily prepared S‐chiral bissulfinamide bearing a five‐methylene linkage not only inherited the excellent substrate generality from the monosulfinamide catalysts, but also exhibited further improved enantioselectivity.
Multiscale characterization framework for sorption enhanced reaction processes
Authors: Kapil Ankur , Bhat Shrikant A. , Sadhukhan Jhuma 
Published: February 2008

AbstractA multiscale simulation and characterization framework has been developed for sorption enhanced reaction processes with heterogeneous multifunctional catalysts with sorption properties. Particles with in situ catalytic and sorption functionalities have obvious advantages in achieving high‐purity and productivity. These processes are strongly limited by diffusion inside particle. In order to tackle this problem a more detailed characterization at particle level is essential, which is the main objective here. A unified framework has been developed that integrates continuum model at bulk scale with the diffusion‐reaction‐sorption model at particle porous scale in a fixed‐bed reactor. At bulk scale the objectives of purity and productivity are sensitive to various design and operating variables, such as wall temperature, bed voidage and feed compositions, etc. Two important particle level characteristics are also identified: distribution of catalyst and sorbent inside particles, and the ratio of pore radius to tortuosity. It has been demonstrated that considering detailed diffusivity model at porous level offers better insights into catalyst design and process intensification. Natural gas reforming reaction with sorption producing pure hydrogen for fuel cell and combustion applications has been used as a case study to establish the effectiveness of the methodology. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Decision framework for chemical process design including different stages of environmental, health, and safety assessment
Authors: Sugiyama Hirokazu , Fischer Ulrich , Hungerbühler Konrad , Hirao Masahiko 
Published: February 2008

AbstractIn recent years, many chemical companies have adopted the concept of sustainable development as a core business value. In this context and with focus on early phases, we present a novel design framework that comprises four stages of process modeling and multiobjective evaluation considering monetary and nonmonetary aspects. Each stage is characterized by the available information as a basis for process modeling and assessment. Appropriate modeling approaches, and evaluation indicators for economy, life‐cycle environmental impacts, environment, health, and safety (EHS) hazard, and technical aspects are selected for each defined stage. The proposed framework is demonstrated on the design of a methyl methacrylate (MMA) process: considering 17 synthesis routes, the framework is mimicked step‐by‐step, to select the route with the best multiobjective performances, and to produce an optimized process flowsheet. As a validation of the framework, evaluation profile of six routes over all stages are compared, and crucial points are identified that should be estimated considerably well in early stages of the framework. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Causes of work‐related injuries among young workers in British Columbia
Authors: Holizki Theresa , McDonald Rose , Foster Valerie , Guzmicky Michael 
Published: February 2008

AbstractBackgroundWe conducted a study to determine the types and causes of serious injuries to young workers (YW) (ages 14–24) in British Columbia.MethodsThe WorkSafeBC database from 2000 to 2005 was searched for all claims, all non‐health‐care‐only (NHCO) injuries and all serious injury claims involving workers aged 14–24.ResultsOf 384,250 NHCO claims, 15.6% were for YW, not significantly different from the British Columbia workforce (P > 0.75). Of the 5217 serious injuries, 9.8% (including 40 fatalities) were to YW—455 males and 56 females, significantly different from the workforce (50% male) (2 = 259.8; df = 1; P < 0.001). Ten percentage of YW injuries occurred in the first week, 20% in the first month, of employment. Education level of injured YWs was lower than average for the provincial workforce. Only 38% of YWs injured in vehicle crashes (the most common cause of fatalities) were wearing seatbelts.ConclusionsSafety training should be provided before YWs start work and in media other than school. Seatbelt use should be addressed. Am. J. Ind. Med. 51:357–363, 2008. © 2008 Wiley‐Liss, Inc.
Synthesis of polypyrrole nanofibers by ultrasonic waves
Authors: Athawale Anjali A. , Katre Prachi P. , Bhagwat S. V. , Dhamane A. H. 
Published: February 2008

AbstractNanofibers of polypyrrole have been synthesized by sonochemical method in the presence of a structure directing agent, i.e. dodecyl benzene sulphonic acid (DBSA). The length of the fibers is seen to increase significantly from ∼13 nm to greater than ∼1700 nm, while the diameter is ∼13–17 nm, respectively. The reaction was carried out under ambient conditions by varying the concentration of pyrrole (0.001–0.1M), ammonium persulphate (0.0075–0.02M), and DBSA (0.05–0.2M). However, the formation of fibers is observed at a specific ratio of 1 : 0.5 : 5. The UV–vis spectra exhibit a sharp peak at a wavelength of ∼490 nm corresponding to the polaron band indicating the formation of polypyrrole. The X‐ray diffractogram shows a broad peak in the 2θ range of ∼10°–30° and two sharp peaks at ∼31° and 32° confirming the formation of polypyrrole. The morphological analysis of the sample have been carried out by transmission as well as scanning electron microscopy which reveals the formation of extraordinary long fibers having the length extending to more than ∼1700 nm. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of cellulose sulfate from α‐cellulose isolated from Lantana camara by the direct esterification method
Authors: Bhatt Neetu , Gupta P. K. , Naithani Sanjay 
Published: February 2008

AbstractCellulose, a (1→4)‐linked β‐D‐glucopyranosyl polysaccharide, is the main plant cell wall constituent and is water insoluble in its native form. Sodium cellulose sulfate possesses excellent water solubility at degree of substitution (DS) levels as low as 0.25. Cellulose sulfate was prepared from α‐cellulose isolated from Lantana camara by sulfation in a heterogeneous medium. The variables studied were reaction time, reaction temperature, normality of sulfuric acid, and quantity of sulfuric acid. A water‐soluble cellulose sulfate ester with a DS of 0.392 was obtained at a reaction time of 60 min, a temperature 0°C, a normality of 34.2N aqueous sulfuric acid, and a quantity of aqueous sulfuric acid of 40 mL/g of α‐cellulose. The optimized product exhibited cold‐water solubility and a clear solution in an aqueous medium, which suggested interesting rheological properties. The optimized product was further evaluated with IR spectroscopy, scanning electron microscopy, thermogravimetric analysis/differential thermal analysis, and wide‐angle X‐ray diffraction. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Transgenic plant factories for the production of biopolymers and platform chemicals
Authors: van Beilen Jan B. 
Published: February 2008

AbstractIn the mid‐to long‐term, resource constraints will force society to cover a significant share of the future demand for fuels, materials and chemicals by renewable resources. This trend is already visible in the increasing conversion of carbohydrates and plant oils to fuels, chemicals, and polymers. In this perspective, we discuss current efforts and ideas to produce platform chemicals and polymers directly in transgenic plants. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd
Structure‐activity relationship study and NMR analysis of fluorobenzoyl pentapeptide GPR54 agonists
Authors: Tomita Kenji , Oishi Shinya , Ohno Hiroaki , Fujii Nobutaka 
Published: February 2008

AbstractGPR54 is a Gq‐protein coupled receptor involved in cancer metastasis and regulation of the endocrine system. GPR54 activation by endogenous ligands attenuates the mobility of carcinomas and stimulates the secretion of gonadotropin‐releasing hormone. GPR54 agonists are, therefore, potential therapeutic candidates for cancer metastasis and hormonal diseases. Pentapeptide derivatives of kisspeptin C‐terminus were identified as potent GPR54 agonists in our previous studies. In the present study, we investigated the structure‐activity relationship of a variety of pentapeptides having various fluorine‐substituted benzoyl groups at the N‐terminus. Among these, a 4‐fluorobenzoyl derivative was the most potent agonist. On the other hand, the derivatives having multiple fluoro‐substituting groups showed less binding affinity. NMR analysis of these peptides and their N‐terminal partial structures suggested that fluorine substituents affect the benzoyl conformation. o‐Monofluorobenzoyl is likely to be in a coplanar conformation due to the intramolecular CFHN hydrogen bonding between o‐fluorine and amide hydrogen; the o,o‐difluorobenzoyl moiety exists in a distorted conformation probably due to the steric hindrance and/or electrostatic repulsion between two o‐fluorine atoms and carbonyl oxygen. © 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 503–511, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Peptide‐polymer biotherapeutic synthesis on novel cross‐linked beads with “spatially tunable” and “isolated” functional sites
Authors: Jacob M. K. , Leena S. , Kumar K. S. 
Published: February 2008

AbstractSolid phase synthesis of polymer biotherapeutics using conventional polymers suffers from many limitations such as low synthetic yield and purity. The conventional polymers prepared by either pre‐ or post‐functionalization strategies have no control over the point of functionalization. Hence we report a novel cross‐linked polymer in which the functional groups are spatially tuned to predefined distance with optimal site isolation. This has been achieved by the design and synthesis of a tetra functional PEG, 3,3′‐(PEG)bis(1‐(4‐vinylphenoxy)propan‐2‐ol) (bis(VPP)PEG). It has been incorporated at cross‐linking of 1–12%, into a polystyrene network by free radical suspension polymerization. In this polymer, the distance between hydroxyl functional groups has been spatially tuned in a predefined manner by varying the length of the cross‐linker backbone from ethylene glycol to PEG1000 Da and the loading capacity could be varied from 0.1 to 0.9 mmol/g. The polymer has been characterized by SEM, FTIR, and 13C NMR. The polymer exhibits excellent swelling behavior and high chemical stability. The synthetic efficiency of the polymer was demonstrated by the successful synthesis of three structural classes of PEGylated antimicrobial peptide biotherapeutics and the difficult ACP (65–74) fragment. Thus the “spatially defined” and “site isolated” synthesis within the new polymer offers a novel strategy for synthesis of difficult peptide‐polymer bioconjugates. The bioassay studies shows that PEGylation of AMPs significantly reduces their hemolytic potential but the retainment of antibacterial property was dependent both on the peptide sequence and the size of PEG used. © 2008 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 512–525, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Tropomyosin expression and dynamics in developing avian embryonic muscles
Authors: Wang Jushuo , Thurston Harold , Essandoh Eugene , Otoo Mary , Han Mingda , Rajan Arun , Dube Syamalima , Zajdel Robert W. , Sanger Jean M. , Linask Kersti K. , Dube Dipak K. , Sanger Joseph W. 
Published: February 2008

AbstractThe expression of striated muscle proteins occurs early in the developing embryo in the somites and forming heart. A major component of the assembling myofibrils is the actin‐binding protein tropomyosin. In vertebrates, there are four genes for tropomyosin (TM), each of which can be alternatively spliced. TPM1 can generate at least 10 different isoforms including the striated muscle‐specific TPM1α and TPM1κ. We have undertaken a detailed study of the expression of various TM isoforms in 2‐day‐old (stage HH 10–12; 33 h) heart and somites, the progenitor of future skeletal muscles. Both TPM1α and TPM1κ are expressed transiently in embryonic heart while TPM1α is expressed in somites. Both RT‐PCR and in situ hybridization data suggest that TPM1κ is expressed in embryonic heart whereas TPM1α is expressed in embryonic heart, and also in the branchial arch region of somites, and in the somites. Photobleaching studies of Yellow Fluorescent Protein‐TPM1α and ‐TPM1κ expressed in cultured avian cardiomyocytes revealed that the dynamics of the two probes was the same in both premyofibrils and in mature myofibrils. This was in sharp contrast to skeletal muscle cells in which the fluorescent proteins were more dynamic in premyofibrils. We speculate that the differences in the two muscles is due to the appearance of nebulin in the skeletal myocytes premyofibrils transform into mature myofibrils. Cell Motil. Cytoskeleton 2008. © 2008 Wiley‐Liss, Inc.
Design, Synthesis, and Stereochemical Evaluation of a Novel Chiral Amine–Palladacycle
Authors: Ding Yi , Li Yongxin , Zhang Yi , Pullarkat Sumod A. , Leung Pak‐Hing 
Published: February 2008

AbstractA novel chiral palladacycle containing ortho‐metallated (±)‐1‐(3,6‐dimethylnaphthalen‐2‐yl)‐N,N‐dimethylethylaminewas designed and synthesized by a multi‐step synthesis by using 2,7‐dimethylnaphthalene as the starting material. The structure and palladacycle ring conformation of the triphenylphosphane derivative was investigated by X‐ray structural analysis in the solid state and by 2D ROESY NMR spectroscopy in solution. Through a designed intramolecular steric interaction, the five‐membered naphthylamine chelate can be locked into a fixed conformation, both in the solid state and in solution. The racemic cyclopalladated complex could be efficiently resolved through the formation of its (S)‐prolinato and (S)‐alaninato derivatives. The structure and absolute configuration of the two optically resolved palladium complexes were determined by X‐ray diffraction. Both the (R,R) and (S,S)‐di‐μ‐chlorido dimeric palladium complexes containing the resolved amine ligand was obtained chemoselectively by treating the corresponding prolinato and alaninato derivatives with 1 M hydrochloric acid. Despite the severe interchelate steric constraint within these new organopalladium complexes, the bulky monodentate ligand 3,4‐dimethyl‐1‐phenylphosphole (dmpp) was able to split the chlorido bridges regiospecifically in the position trans to the NMe2 group. With the new palladacycle used as the chiral template, the stereoselectivity of Diels–Alder cycloaddition between dmpp and ethyl vinyl ketone significantly improves relative to that of other analogue complexes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Characterization of DNA Layers Adsorbed on Glassy Carbon Electrodes
Authors: Pedano María L. , Pietrasanta Lía I. , Teijelo Manuel López , Rivas Gustavo A. 
Published: February 2008

AbstractA DNA layer adsorbed at glassy carbon electrodes (GCE) was characterized by ellipsometry, atomic force microscopy (AFM) and scanning electron microscopy (SEM). The presence of the adsorbed DNA layer on polished glassy carbon electrodes was assessed indirectly by ellipsometric measurements. Ellipsometry was also useful to evaluate the influence of the oxide layer formed on glassy carbon electrodes, either spontaneously or after electrochemical pretreatments, on the DNA adsorption and further electrooxidation process. SEM and AFM images of the electrode surface covered by a thick layer of DNA reveal a nonuniform distribution, leaving channels and islands of the biological material.
Simultaneous Determination of Glucose and L‐Glutamate Using a Capillary Enzyme Reactor with Electrochemical Detection
Authors: Hooper Stephanie E. , Anderson Mark R. 
Published: February 2008

AbstractAn electrophoresis capillary that incorporates two enzymes for the simultaneous determination of glucose and L‐glutamate is described. The enzymes deposited along the separation capillary walls react with their respective substrate as they are separated during the electrophoresis to produce hydrogen peroxide that is detected by amperometry as the hydrogen peroxide zone emerges from the end of the capillary. Even though both enzyme reactions produce a common product, hydrogen peroxide, the hydrogen peroxide produced by each enzyme reaction stays in narrow zones that migrate the length of the capillary at different rates. The rate of migration for the individual H2O2 zones is consistent with the expected mobility of neutral glucose and of anionic L‐glutamate, respectively. This property allows each enzyme substrate to be characterized in a single experiment and in the presence of other electroactive substances.
Technical Concept of a Flow‐through Microreactor for In‐situ RT‐PCR
Authors: Felbel J. , Reichert A. , Kielpinski M. , Urban M. , Häfner N. , Dürst M. , Köhler J. M. , Weber J. , Henkel T. 
Published: February 2008

AbstractThis paper presents a novel flow‐through reverse transcription‐polymerase chain reaction (RT‐PCR) microreactor with optimized thermal and fluidic characteristics. It integrates the steps of reverse transcription of the initially applied RNA sample and the amplification of specific DNA fragments of the cDNA formed. The microreactor comprises a heating plate with different temperature zones and an interchangeable fluidic chip with serpentine microchannels. The heating plate provides temperature zones for reverse transcription, hot start activation, denaturation, annealing and extension. The fluidic chip contains a serpentine microchannel with integrated features for segmented sample stream generation and dosing operations, which is guided over the temperature zones according to the thermal protocol of RT‐PCR. Reverse transcription is performed in an integrated microchannel section immediately before the amplification of the cDNA's, generated from the primarily applied RNA sample. One feature of this chip system is the generation of a segmented flow for high‐throughput analysis of RT‐PCR samples. It is shown that RT‐PCR reactions can be performed successfully in the microreactor with continuous and segmented flow regimes. The aim of the experiments was the detection of the HPV 16 DNA genome and of viral oncogene transcripts (E6/E7), respectively. Both markers are of importance in medical diagnostics and will be applied in further studies for the identification of oncogene positive cells in cell populations by means of flow‐through in‐situ RT‐PCR.
System Development for Generating Homogeneous Cell Suspensions and Transporting them in Microfluidic Components
Authors: Schumacher J. T. , Grodrian A. , Lemke K. , Römer R. , Metze J. 
Published: February 2008

AbstractMiniaturized biological test assays require an even distribution of the utilized cells in every single segment. For the cell dispension, two devices with a volume of about 2 milliliter were developed enabling simultaneous mixing and processing of suspensions into capillaries. These items will be used to generate homogeneous suspensions for a duration of up to one hour and distributing them with special microfluidic chips. Both devices could be easily sterilized by autoclaving and contain an agitator which is contactlessly driven with variable speed. Precise transportation of the mixed fluid in the lower microliter per minute range was realized by the use of syringe pumps. Suspensions with yeast, mammalian cells and beads were applied to investigate the efficiency of mixing and transportation as well as the effect on viability. At certain time intervals, samples were taken from the outlet, and the cell and bead content with the related viability was determined using an automated particle analyzer and counting chamber under the microscope. Yeast suspensions were handled up to two hours and hybridoma cells up to one hour without remarkable loss of viability whereby the degree of mixing was sufficient for these time periods. The results show that these modules are feasible tools for homogeneous mixing of cell suspensions, and transport through microfluidic devices allows dispensation of them into fluid segments on a microliter or nanoliter scale.