bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plastics Testing
Authors: Shah Vishu 
Published: January 2013

Abstract
The present chapter reviews plastic material. Plastics, unlike metals, ceramics, and other traditional materials, do not exhibit a linear stress‐strain relationship and are sensitive to change in temperature, rate of loading environment, and so on. Over the years ASTM has done an excellent job in developing and providing the plastic industry with standard testing procedures. These standards have and continue to play a preeminent role in all aspects important to the effective utilization of plastics. The study finds that mechanical properties, among all the properties of plastic materials, are often the most important properties because virtually all service conditions and the majority of end‐use applications involve some degree of mechanical loading. Several tests have been presented to study the fatigue behavior, hardness, and thermal, optical, and electrical properties of plastic materials. The study also notes that environmental factors have significant detrimental effects on appearance and properties. Therefore, any attempt to design plastic parts without a clear understanding of the degradation mechanisms induced by the environment would result in a premature failure of the product.
Data Acquisition and Display Systems
Authors: Milliman Philip C. 
Published: January 2013

AbstractData acquisition includes acquiring raw data from the process being measured and converting data into usable units. A digital‐to‐analog (D/A) and analog‐to‐digital (A/D) converter performs the actual processing required to bring analog information from or to the process. This chapter attempts to cover aspects of data acquisition and manipulation that may help the engineer better understand issues and give a foundation for using and even constructing tools. A discussion of pros and cons of different strategies helps the reader to understand the trade‐offs in system selection and construction. Often the data obtained from a process are not in the form or units desired and several methods of transforming data to produce proper units, reduce storage quantity, and reduce noise have been described. The current values can be inspected and stored for inspection later, values can be trended, alarm conditions can be detected and reported, or some output back to the process can be performed. Finally, all relevant aspects regarding data analysis and data communications have been displayed comprehensively. Other data acquisition and display topics have also been covered such as data chain, web programs and interfaces, configuration versus implementation and store and forward.
Enzymatic Fragment Condensation of Side Chain‐Protected Peptides using Subtilisin A in Anhydrous Organic Solvents: A General Strategy for Industrial Peptide Synthesis
Authors: Nuijens Timo , Schepers Annette H. M. , Cusan Claudia , Kruijtzer John A. W. , Rijkers Dirk T. S. , Liskamp Rob M. J. , Quaedflieg Peter J. L. M. 
Published: January 2013

AbstractHerein, the enzymatic condensation of side chain‐protected peptide fragments using subtilisin A in anhydrous organic solvents is described. A screening with dipeptide Cbz‐Val‐Xxx carboxamidomethyl esters with H‐Xxx‐Val‐NH2 nucleophiles was performed, wherein Xxx stands for every (side chain‐protected) amino acid residue. Finally, it was demonstrated that it is feasible to enzymatically condense larger peptide fragments (up to the 10‐mer level) bearing multiple side chain‐protecting groups with very high conversion.
Preactivation: An Alternative Strategy in Stereoselective Glycosylation and Oligosaccharide Synthesis
Authors: Yang Lin , Qin Qi , Ye Xin‐Shan 
Published: January 2013

AbstractThe multifaceted biological importance of carbohydrates has made them very popular targets in modern synthetic chemistry. Great progress has been made in stereoselective glycosylation methods and the construction of complex oligosaccharides. This Focus Review highlights the versatile applications of preactivation strategies in stereoselective glycosylation and oligosaccharide synthesis. Recent advances in synthetic methods, such as 4,6‐O‐benzylidene‐acetal‐directed β‐mannosylation, the 1,2‐cis‐glycosylation mediated by a chiral auxiliary, the use of an oxazolidinone or carbonate protecting group, and glycosylation with participating additives, are described. Various examples of sequential glycosylation based on preactivation protocols for efficient oligosaccharide assembly are also summarized.
Iron‐Functionalized Silica Nanoparticles as a Highly Efficient Adsorbent and Catalyst for Toluene Oxidation in the Gas Phase
Authors: Popova Margarita , Ristić Alenka , Lazar Karoly , Maučec Darja , Vassileva Mihaela , Novak Tušar Nataša 
Published: January 2013

AbstractCatalytic oxidation is one of the most important industrially applicable processes for the decomposition of volatile organic compounds (VOCs) in polluted air. The advanced VOC removal process is composed of an adsorption unit and a catalytic incinerator. Many efforts have been made to design a combined adsorption–catalytic unit with optimal activity and selectivity. We demonstrate that iron‐functionalized silica nanoparticles with interparticle mesoporosity (FeKIL‐2) act as highly efficient adsorbents and catalysts with optimal Fe/Si molar ratios of 0.01 in toluene oxidation as model VOCs in the gas phase. By using UV/Vis, FTIR, and Mössbauer spectroscopic techniques, we prove that the enhanced activity of the catalyst is attributed to iron incorporated into the silica matrix, which depends on the iron content. The iron content with Fe/Si≤0.01 leads to the formation of stable Fe3+ ions in the silica matrix, which ensures easier oxygen release from the catalyst (Fe3+/Fe2+ redox cycles). The increase in the iron content with Fe/Si>0.01 leads to the formation of oligonuclear iron complexes. The material thus introduces a promising, environmentally friendly, cost‐effective, and highly efficient catalyst with combined adsorption and catalytic properties for the removal of low‐concentration VOC from polluted air.
TetrathiafulvaleneBenzothiadiazoles as Redox‐Tunable Donor–Acceptor Systems: Synthesis and Photophysical Study
Authors: Pop Flavia , Amacher Anneliese , Avarvari Narcis , Ding Jie , Daku Latevi Max Lawson , Hauser Andreas , Koch Marius , Hauser Jürg , Liu Shi‐Xia , Decurtins Silvio 
Published: January 2013

AbstractElectrochemical and photophysical analysis of new donor–acceptor systems 2 and 3, in which a benzothiadiazole (BTD) unit is covalently linked to a tetrathiafulvalene (TTF) core, have verified that the lowest excited state can be ascribed to an intramolecular‐charge‐transfer (ICT) π(TTF)→π*(benzothiadiazole) transition. Owing to better overlap of the HOMO and LUMO in the fused scaffold of compound 3, the intensity of the 1ICT band is substantially higher compared to that in compound 2. The corresponding CT fluorescence is also observed in both cases. The radical cation TTF+. is easily observed through chemical and electrochemical oxidation by performing steady‐state absorption experiments. Interestingly, compound 2 is photo‐oxidized under aerobic conditions.
Synchronizing Steric and Electronic Effects in {RuII(NNNN,P)} Complexes: The Catalytic Dehydrative Alkylation of Anilines by Using Alcohols as a Case Study
Authors: Weickmann Daniel , Frey Wolfgang , Plietker Bernd 
Published: January 2013

AbstractA series of new hexacoordinated {RuII(NNNN,P)} complexes was prepared from [RuCl2(R3P)3]. Their structure was determined by X‐ray crystallography. The catalytic potential of this new class of complexes was tested in the alkylation of aniline with benzyl alcohol. In this test reaction, the influence of the counteranion plus electronic influences at the tetradentate ligand and the phosphine ligand were examined. The electrochemistry of all complexes was studied by cyclic voltammetry. Depending on the substituent at the ligand backbone, the complexes showed a different behavior. For all N‐benzyl substituted complexes, reversible RuII/III redox potentials were observed, whereas the N‐methyl substituted complex possessed an irreversible oxidation event at small scan rates. Furthermore, the electronic influence of different substituents at the ligand scaffold and at the phosphine on the RuII/III redox potential was investigated. The measured E0 values were correlated to the theoretically determined HOMO energies of the complexes. In addition, these HOMO energies correlated well with the reactivity of the single complexes in the alkylation of aniline with benzyl alcohol. The exact balance of redox potential and reactivity appears to be crucial for synchronizing the multiple hydrogen‐transfer events. The optimized catalyst structure was applied in a screening on scope and limitation in the catalytic dehydrative alkylation of anilines by using alcohols.
Inner Workings of a Cinchona Alkaloid Catalyzed Oxa‐Michael Cyclization: Evidence for a Concerted Hydrogen‐Bond‐Network Mechanism
Authors: Hintermann Lukas , Ackerstaff Jens , Boeck Florian 
Published: January 2013

AbstractCinchona alkaloids catalyze the oxa‐Michael cyclization of 4‐(2‐hydroxyphenyl)‐2‐butenoates to benzo‐2,3‐dihydrofuran‐2‐yl acetates and related substrates in up to 99 % yield and 91 % ee(ee=enantiomeric excess). Catalyst and substrate variation studies reveal an important role of the alkaloid hydroxy group in the reaction mechanism, but not in the sense of a hydrogen‐bonding activation of the carbonyl group of the substrate as assumed by the Hiemstra–Wynberg mechanism of bifunctional catalysis. Deuterium labeling at C‐2 of the substrate shows that addition of ROH to the alkenoate occurs withsyndiastereoselectivity of ≥99:1, suggesting a mechanism‐based specificity. A concerted hydrogen‐bond network mechanism is proposed, in which the alkaloid hydroxy group acts as a general acid in the protonation of the α‐carbanionic center of the product enolate. The importance of concerted hydrogen‐bond network mechanisms in organocatalytic reactions is discussed. The relative stereochemistry of protonation is proposed as analytical tool for detecting concerted addition mechanisms, as opposed to ionic 1,4‐additions.
Microenvironment Effects in Electrocatalysis: Ionic‐Liquid‐Like Coating on Carbon Nanotubes Enhances the Pd‐Electrocatalytic Alcohol Oxidation
Authors: Li Shuwen , Dong Zhengping , Yang Honglei , Guo Shujing , Gou Galian , Ren Ren , Zhu Zhejun , Jin Jun , Ma Jiantai 
Published: January 2013

AbstractA new catalyst consisting of ionic liquid (IL)‐functionalized carbon nanotubes (CNTs) obtained through 1,3‐dipolar cycloaddition support‐enhanced electrocatalytic Pd nanoparticles (Pd@IL(Cl−)‐CNTs) was successfully fabricated and applied in direct ethanol alkaline fuel cells. The morphology, structure, component and stability of Pd@IL(Cl−)‐CNTs were systematic characterized by transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM), Raman spectra, thermogravimetric analysis (TGA) and X‐ray diffraction (XRD). The new catalyst exhibited higher electrocatalytic activity, better tolerance and electrochemical stability than the Pd nanoparticles (NPs) immobilized on CNTs (Pd@CNTs), which was ascribed to the effects of the IL, larger electrochemically active surface area (ECSA), and greater processing performance. Cyclic voltammograms (CVs) at various scan rates illustrated that the oxidation behaviors of ethanol at all electrodes were controlled by diffusion processes. The investigation of the different counteranions demonstrated that the performance of the IL‐CNTs hybrid material was profoundly influenced by the subtly varied structures of the IL moiety. All the results indicated that the Pd@IL(Cl−)‐CNTs catalyst is an efficient anode catalyst, which has potential applications in direct ethanol fuel cells and the strategy of IL functionalization of CNTs could be available to prepare other carbonaceous carrier supports to enhance the dispersivity, stability, and catalytic performance of metal NPs as well.
Molecular and phylogenetic characterization of honey bee viruses, Nosema microsporidia, protozoan parasites, and parasitic mites in China
Authors: Yang Bu , Peng Guangda , Li Tianbang , Kadowaki Tatsuhiko 
Published: January 2013

AbstractChina has the largest number of managed honey bee colonies, which produce the highest quantity of honey and royal jelly in the world; however, the presence of honey bee pathogens and parasites has never been rigorously identified in Chinese apiaries. We thus conducted a molecular survey of honey bee RNA viruses, Nosema microsporidia, protozoan parasites, and tracheal mites associated with nonnative Apis mellifera ligustica and native Apis cerana cerana colonies in China. We found the presence of black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and sacbrood virus (SBV), but not that of acute bee paralysis virus (ABPV) or Kashmir bee virus (KBV). DWV was the most prevalent in the tested samples. Phylogenies of Chinese viral isolates demonstrated that genetically heterogeneous populations of BQCV, CBPV, DWV, and A. cerana‐infecting SBV, and relatively homogenous populations of IAPV and A. meliifera‐infecting new strain of SBV with single origins, are spread in Chinese apiaries. Similar to previous observations in many countries, Nosema ceranae, but not Nosema apis, was prevalent in the tested samples. Crithidia mellificae, but not Apicystis bombi was found in five samples, including one A. c. cerana colony, demonstrating that C. mellificae is capable of infecting multiple honey bee species. Based on kinetoplast‐encoded cytochrome b sequences, the C. mellificae isolate from A. c. cerana represents a novel haplotype with 19 nucleotide differences from the Chinese and Japanese isolates from A. m. ligustica. This suggests that A. c. cerana is the native host for this specific haplotype. The tracheal mite, Acarapis woodi, was detected in one A. m. ligustica colony. Our results demonstrate that honey bee RNA viruses, N. ceranae, C. mellificae, and tracheal mites are present in Chinese apiaries, and some might be originated from native Asian honey bees.
Linking spatial earthworm distribution to macropore numbers and hydrological effectiveness
Authors: van Schaik Loes , Palm Juliane , Klaus Julian , Zehe Erwin , Schröder Boris 
Published: January 2013

ABSTRACTDue to its high spatial and temporal variability, preferential flow is difficult to measure and quantify. Earthworms create macropores that provide common pathways for preferential flow. Therefore in this article, we link earthworm abundance to macropore numbers and hydrological effectiveness, with the future aim to use species distribution models of earthworms for the spatial parameterization of preferential flow.Earthworms are generally categorized into three ecological types with varying burrowing behaviour, resulting in a different impact on soil hydrological processes. Therefore, we studied the relationships between the abundance of the earthworm ecological types and macropores of different size classes and in different soil depths. The abundance and biomass of earthworms were well correlated to different sizes of macropores in different soil depths. This is mainly the case for the larger, vertically oriented macropores (>6 mm diameter), which are generally connected to the soil surface and hydrologically most effective. The correlation of total earthworm biomass and macropores ranges from 0·72 to 0·89 for different soil depths.Although there is quite some variation in infiltration patterns, infiltration from macropores into the matrix is profile‐specific, as it varies strongly between profiles, but not within one profile. Macropore coating seems to have a larger effect on this macropore matrix interaction than the soil physical properties of the matrix. Although the amount of macropores and their effectiveness are clearly related to the earthworm distribution, the variation in infiltration from macropores to soil matrix should be further studied. Copyright © 2013 John Wiley & Sons, Ltd.
Response surface optimization of ultrasonic‐assisted extraction of carotenoids from oil palm (Elaeis guineensisJacq.) fronds
Authors: Ofori‐Boateng C. , Lee K. T. 
Published: January 2013

AbstractOil palm (Elaeis guineensisJacq.) fronds (OPF) are the most abundant oil palm solid wastes that are generated during oil palm agriculture and harvest. Palm oil and some other palm wastes have been reported to contain high concentrations of carotenoids with vital bioactive properties. However, the extraction and quantification of carotenoids fromOPFhave not been reported. In this study, ultrasonic‐assisted extraction,HPLC–FLDfor quantification, and response surface methodology (RSM) for optimization of β‐carotene, lutein, and zeaxanthin fromOPFextracts were investigated. The effects of extraction temperature (X1: 30–70°C), extraction time (X2: 10–50 min), and solvent–sample ratio (X3: 10–50 mL/g) on the recovery of β‐carotene (Y1), lutein (Y2), and zeaxanthin (Y3) were investigated using three‐levelBox–Behnken design (BBD) experiment. At a desirability of 1, the optimum extraction conditions for β‐carotene (30.14°C, 37.11 min, and 23.18 mL/g), lutein (30.00°C, 39.09 min, and 19.24 mL/g), and zeaxanthin (30.09°C, 36.76 min, and 22.38 mL/g) yielded carotenoid concentrations of 17.95 μg/g dry weight (DW), 261.99 μg/gDW, and 29.99 μg/gDW, respectively.
Hepatitis B virus hepatotropism is mediated by specific receptor recognition in the liver and not restricted to susceptible hosts
Authors: Schieck Alexa , Schulze Andreas , Gähler Caroline , Müller Thomas , Haberkorn Uwe , Alexandrov Alexander , Urban Stephan , Mier Walter 
Published: January 2013

Abstract

The human hepatitis B virus (HBV) causes acute and chronic infections in humans and chimpanzees. HBV infects its hosts at minimal inoculation doses and replicates exclusively in hepatocytes. The viral determinants for the pronounced species specificity and the high efficacy to address hepatocytes in vivo are unknown. Previous findings showed that N-terminally myristoylated peptides constituting a receptor binding domain of the HBV large envelope (L)-protein block HBV entry in vitro and in vivo. Here we investigate the ability of such peptidic receptor ligands to target the liver. Injection of radioactively labeled HBVpreS-lipopeptides resulted in rapid accumulation in livers of mice, rats, and dogs but not cynomolgus monkeys. Without lipid moiety the peptide was excreted by renal filtration, indicating its possible retention through the lipid by serum factors. Organ distribution studies of 26 HBVpreS peptide variants revealed a correlation of HBV infection inhibition activity and the ability to target mouse livers. Together with complementary studies using primary hepatocytes of different species, we hypothesize that HBV hepatotropism is mediated through specific binding of the myristoylated N-terminal preS1-domain of the HBV L-protein to a hepatocyte specific receptor. Moreover, the restricted infectivity of HBV to human primates is not generally determined by the absence of this binding receptor in nonsusceptible hosts (e.g., mice) but related to postbinding step(s) (e.g., membrane fusion).
Conclusion
: HBVpreS-lipopeptides target to the liver. This observation has important clinical implications regarding the pharmacokinetic properties of Myrcludex B, the first entry inhibitor for HBV/HDV. In addition, this provides the basis for the application of the peptides as vehicles for hepatocyte-specific drug targeting. (HEPATOLOGY 2013)
Coupled heat and mass transfer by MHD free convection flow along a vertical plate with streamwise temperature and species concentration variations
Authors: Chamkha Ali J. , EL‐Kabeir S.M.M. , Rashad A.M. 
Published: December 2012

AbstractThe problem of steady, laminar, coupled heat and mass transfer by MHD free convective boundary‐layer flow along a vertical flat plate with the combined effects of streamwise sinusoidal variations of both the surface temperature and the species concentration in the presence of Soret and Dufour effects is considered. A suitable set of dimensionless variables is used to transform the governing equations of the problem into a non‐similar form. The resulting non‐similar equations have the property that they reduce to various special cases previously considered in the literature. An adequate and efficient implicit, tri‐diagonal finite difference scheme is employed for the numerical solution of the obtained equations. Various comparisons with previously published work are performed and the results are found to be in excellent agreement. A representative set of numerical results for the velocity, temperature, and concentration profiles as well as the surface shear stress, rate of heat transfer, and the rate of mass transfer is presented graphically for various parametric conditions and is discussed. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21033
Stem Cell Models for Drug Discovery and Toxicology Studies
Authors: Liu Wenwei , Deng Yaguang , Liu Ying , Gong Wenrong , Deng Wenbin 
Published: January 2013

ABSTRACTHuman stem cells and their derivatives could provide virtually unlimited sources of tissue for a wide range of toxicity models that could complement conventional animal models with more relevant, humanized versions. Human embryonic stem cells (hESCs) have already been proven valuable for drug/toxicity screens and mechanistic studies including analysis of disease pathway and developmental toxicity. Human‐induced pluripotent stem cells (iPSCs), which are generated by reprogramming somatic cells back to become hESC‐like cells, allow assays to be designed where the contribution of an individual's genetic background or environmental exposure history to toxicity response can be determined. Comprehensive profiling of hESC/iPSCs via genomics, proteomics, transcriptomics, and metabolomics could be used to elucidate pathway perturbations that underlie toxicity and disease, enabling the development of predictive assays for toxicity. While technological hurdles still exist for widespread use and implementation, incorporation of human stem cell based assays into drug discovery and toxicity testing offers the potential for safer, more customized medicines and more accurate risk assessment for environmental toxicants, as well as reduced costs and decreased use of animal models. We examine limitations and deficiencies of current toxicology approaches and how human stem cell based in vitro assays may overcome them. We describe how human stem cells are used for predictive toxicology. We also identify technological limitations that prevent stem cells from being integrated into standard practice, as well as new tools and technologies that may overcome them. We discuss research priorities that are most useful for transforming cell‐based toxicology models into reality, and research areas in which stem cell technology could make substantial contributions to the development and implementation of stem cell based models for toxicity testing. Increased use of human in vitro models of toxicity could reduce the use of animals in safety and risk assessment studies and offers the potential to dramatically enhance our understanding of the molecular basis of toxicity, leading to improved human models and assays for predicting biological response to drugs and environmental hazards. © 2012 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:17‐27, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.21470