bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of a new titanium dual initiator for the synthesis of poly(ε‐caprolactone)‐b‐polystyrene block copolymers by the combination of coordination and nitroxide mediated polymerizations
Authors: Li Xinxin , Jeanmaire Thomas , Zerroukhi Amar 
Published: December 2007

AbstractPoly ε‐caprolactone‐polystyrene block‐copolymers (PCL‐b‐PSt) were synthesized using a modified titanium catalyst as the dual initiator. Alcoholysis of Ti(OPr)4 by 4‐hydroxy 2,2,6,6 tetramethyl piperidinyl‐1‐oxyl (HO‐TEMPO) gave a bifunctional initiator Ti(OTEMPO)4. Poly ε‐caprolactone prepolymer end‐capped with the nitroxide group was first prepared by ring opening polymerization of ε‐caprolactone with this initiator at high conversion. The nitroxide‐end‐capped structure and molar mass (Mn) of the polymers were demonstrated by typical UV absorption band. This analytical technique indicates a near‐quantitative nitroxide functionality and a Mn in good agreement with size exclusion chromatography (SEC) ones. This polyester prepolymer was used to further initiate the radical polymerization with styrene and reach the block copolymers (PCL‐b‐PSt). All the prepolymers and block copolymers were characterized by SEC and NMR spectroscopy. Additionally, the preparation of star polymers bearing two kinds of arms (PCL and PSt) was envisaged and a preliminary result was given. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Structural characterization and dynamic water adsorption of electrospun polyamide6/montmorillonite nanofibers
Authors: Li Qi , Wei Qufu , Wu Ning , Cai Yibing , Gao Weidong 
Published: December 2007

AbstractA facile compounding process, which combined nanocomposite process with electrospinning for preparing novel polyamide6/organic modified montmorillonite (PA6/O‐MMT) composite nanofibers, is reported. In this compounding process, the O‐MMT slurry was blended into the formic acid solution of PA6 at moderate temperatures, where the nanosized O‐MMT particles were first dispersed in N,N‐dimethyl formamide solvent homogeneously via ultrasonic mixing. Subsequently the solution via electrospinning formed nanofibers, which were collected onto aluminum foil. The O‐MMT platelets were detected to be exfoliated at nanosize level and dispersed homogeneously along the axis of the nanofibers using an electron transmission microscope. Scanning electron microscope and atomic force microscope were used to analysis the size and surface morphology of polyamide6/O‐MMT composite nanofibers. The addition of O‐MMT reduced the surface tension and viscosity of the solution, leading to the decrease in the diameter of nanofiber and the formation of rough and ridge‐shape trails on the nanofiber surface. The behavior of the dynamic water adsorption of composite nanofibers was also investigated and discussed in this article. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Novelty and topicality in interactive information retrieval
Authors: Xu Yunjie , Yin Hainan 
Published: December 2007

AbstractThe information science research community is characterized by a paradigm split, with a system‐centered cluster working on information retrieval (IR) algorithms and a user‐centered cluster working on user behavior. The two clusters rarely leverage each other's insight and strength. One major suggestion from user‐centered studies is to treat the relevance judgment of documents as a subjective, multidimensional, and dynamic concept rather than treating it as objective and based on topicality only. This study explores the possibility to enhance users' topicality‐based relevance judgment with subjective novelty judgment in interactive IR. A set of systems is developed which differs in the way the novelty judgment is incorporated. In particular, this study compares systems which assume that users' novelty judgment is directed to a certain subtopic area and those which assume that users' novelty judgment is undirected. This study also compares systems which assume that users judge a document based on topicality first and then novelty in a stepwise, noncompensatory fashion and those which assume that users consider topicality and novelty simultaneously and as compensatory to each other. The user study shows that systems assuming directed novelty in general have higher relevance precision, but systems assuming a stepwise judgment process and systems assuming a compensatory judgment process are not significantly different.
Capital punishment and anatomy: History and ethics of an ongoing association
Authors: Hildebrandt S. 
Published: December 2007

AbstractAnatomical science has used the bodies of the executed for dissection over many centuries. As anatomy has developed into a vehicle of not only scientific but also moral and ethical education, it is important to consider the source of human bodies for dissection and the manner of their acquisition. From the thirteenth to the early seventeenth century, the bodies of the executed were the only legal source of bodies for dissection. Starting in the late seventeenth century, the bodies of unclaimed persons were also made legally available. With the developing movement to abolish the death penalty in many countries around the world and with the renunciation of the use of the bodies of the executed by the British legal system in the nineteenth century, two different practices have developed in that there are Anatomy Departments who use the bodies of the executed for dissection or research and those who do not. The history of the use of bodies of the executed in German Anatomy Departments during the National Socialist regime is an example for the insidious slide from an ethical use of human bodies in dissection to an unethical one. There are cases of contemporary use of unclaimed or donated bodies of the executed, but they are rarely well documented. The intention of this review is to initiate an ethical discourse about the use of the bodies of the executed in contemporary anatomy. Clin. Anat. 21:5–14, 2008. © 2007 Wiley‐Liss, Inc.
Tailor‐Made Fructooligosaccharides by a Combination of Substrate and Genetic Engineering
Authors: Zuccaro Alga , Götze Sven , Kneip Susanne , Dersch Petra , Seibel Jürgen 
Published: December 2007

AbstractThe combination of sucrose analogues as novel substrates (substrate engineering) and highly active recombinant β‐fructofuranosidase from A. niger (genetic engineering) provides a new powerful tool for the efficient preparative synthesis of tailor‐made saccharides of the important 1‐kestose and 1‐nystose type headed with different monosaccharides of interest. These novel compounds have been isolated. They did not display toxic effects or suppress cell growth in initial studies, making these new compounds potential candidates for prebiotics.
A Process Integration based Approach for the Analysis of an Evaporator System
Authors: Khanam S. , Mohanty B. 
Published: December 2007

AbstractA scalable new mathematical model based on the principles of Process Integration has been developed for the analysis of multiple effect evaporator (MEE) systems. It uses the concepts of stream analysis, temperature path and internal heat exchange for the formulation of the model equations. In addition to the above concepts, the model also takes into account the variable physico‐thermal properties of steam/vapor, condensate and liquor, while simulating the MEE system. The present model consists of a set of linear equations and does not present any stability or oscillation problems during solution as is generally seen in the case of models that are based on sets of nonlinear equations. The model equations are automatically generated through a computer program and the model was run for three different liquor and flow sequences to prove its utility. The results obtained are compared with published models.
Magnetic Field, Flow Field and Inclusion Collision Growth in a Continuous Caster with EMBR
Authors: Lei H. , Xu G. , He J. 
Published: December 2007

AbstractA three‐dimension mathematical model has been developed to describe the magnetic field, fluid flow and inclusion transport in a continuous caster with electromagnetic brake (EMBR). According to the model, all the governing equations can be expressed as a general differential equation, so a general numerical method was developed to solve these equations. The numerical results agree well with the experimental result. In the continuous caster, the inclusion distributions have ‘M’ shape under the nozzle and ‘W’ shape at the exit, which come from the centrifugal effect and the collision and aggregation among inclusions. The three‐dimensional static magnetic field can effectively damp local flows and affect the inclusion transport in a continuous caster. If EMBR is installed under the nozzle, it can promote the inclusion removal and the inclusion ‘M’ distribution disappears.
Study of the Effects of External and Internal Diffusion on the Propane Dehydrogenation Reaction over Pt‐Sn/Al2O3 Catalyst
Authors: Mohagheghi M. , Bakeri G. , Saeedizad M. 
Published: December 2007

AbstractIn the study of a reaction on a heterogeneous catalyst, external and internal mass diffusion play an important role since they can have an inherent affect on the kinetics of the reaction. Therefore, in the study of intrinsic rates of reaction, the effects of external and internal mass diffusion must be eliminated or considered prior to proper kinetic studies. In this study, the effects of external and internal mass diffusion on the propane dehydrogenation reaction over a Pt/Sn catalyst were investigated. Some experiments were performed in a laboratory scale setup and the required data was gathered. The rate of reaction was considered to be first order based on propane. External diffusion was studied using Mears' criterion and internal diffusion was investigated by the Thiele Module and the Internal Effectiveness Factor, based on experimental data.
Spray Scrubbing of Particulates with a Critical Flow Atomizer
Authors: Bandyopadhyay A. , Biswas M. N. 
Published: December 2007

AbstractWet scrubbers are gaining importance over other devices for particulate collection with the increasing stringency of pollution regulations. The scrubbing of particulates (soot and fly‐ash) in a spray tower with a two‐phase critical flow atomizer using water is reported in this article. The atomizer is capable of generating droplets with a high degree of spray uniformity. Preliminary studies reveal that the atomizer deployed in the present investigation is energetically more favorable than existing atomizers. With this atomizer, the scrubbing performances of a model spray tower are determined experimentally in terms of different operating variables. Various physical interactions with the exception of electrostatic effects are found to significantly influence the removal efficiency. The removal efficiency is found to increase with the inlet particle loading, gas flow rate and liquid to gas flow rate ratio. Experiments reveal that the present system collects finer (soot) particles (with a Sauter Mean Diameter (SMD) of 1.43 μm) more efficiently than the relatively coarse (fly‐ash) particles (SMD of 6.38 μm) under similar experimental conditions. Further investigation reveals that almost 100 % removal efficiency (zero penetration) of both soot and fly‐ash particles can be attained at a much lower QL/QG ratio of 3 m3/1000 actual cubic meters (ACM) than for the existing systems. A unique correlation is developed for predicting the performance of the spray tower in terms of various pertinent variables of the system. The predicted values agree very well with the experimental values (± 10 % deviation). A comparison of the performance of the present system with the existing systems indicates that the spray tower developed is techno‐enviro‐economically more favorable than existing systems.
Effects of Additives on the Activity and Enantioselectivity of Candida rugosa Lipase in a Biphasic Medium
Authors: Salgın S. , Takaç S. 
Published: December 2007

AbstractThe effects of Li+, Na+, K+, Mg2+ and Zn2+ ions on the activity and enantioselectivity of Candida rugosa lipase (CRL) were investigated in a biphasic medium composed of phosphate buffer solution (containing a metal ion within a 50–500 mM concentration range) and isooctane. The hydrolytic activities of CRL towards p‐nitrophenyl acetate were measured after incubation of the enzyme in the presence of metal ions for 24 h, and they were compared to that obtained after incubation in the absence of any metal ion. The CRL activity was stimulated by the chloride salts of Li+, K+ and Mg2+ for all concentrations considered and the highest enhancement was achieved by Li+ with a 1.24–1.75 fold increase observed. The effects of metal ions on the enantioselectivity of CRL were investigated by performing the hydrolysis of racemic Naproxen methyl ester in the same biphasic medium containing Li+, Na+, K+, Mg2+ and Zn2+ ions. The addition of metal ions increased the hydrolysis rate by ca. 1.31–1.45 fold relative to the control, whereas the enantiomeric excess of product increased slightly in the presence of the metal ions. The effect of Triton X‐100 on the activity and enantioselectivity of the CRL was also investigated by employing 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 mM concentrations of it in phosphate buffer solution of the biphasic medium. High concentrations of Triton X‐100 stimulated the enzyme activity up to 1.66 fold after 24 h incubation. Triton X‐100 increased the hydrolysis rate almost independently of the concentration.
Amavadin and Other Vanadium Complexes as Remarkably Efficient Catalysts for One‐Pot Conversion of Ethane to Propionic and Acetic Acids
Authors: Kirillova Marina V. , Kuznetsov Maxim L. , da Silva José A. L. , Guedes da Silva Maria Fátima C. , Fraústo da Silva João J. R. , Pombeiro Armando J. L. 
Published: December 2007

AbstractSynthetic amavadin Ca[V{ON[CH(CH3)COO]2}2] and its models Ca[V{ON(CH2COO)2}2] and [VO{N(CH2CH2O)3}], in the presence of K2S2O8 in trifluoroacetic acid (TFA), exhibit remarkable catalytic activity for the one‐pot carboxylation of ethane to propionic and acetic acids with the former as the main product (overall yields up to 93 %, catalyst turnover numbers (TONs) up to 2.0×104). The simpler V complexes [VO(CF3SO3)2], [VO(acac)2] and VOSO4 are less active. The effects of various factors, namely, C2H6 and CO pressures, time, temperature, and amounts of catalyst, TFA and K2S2O8, have been investigated, and this allowed optimisation of the process and control of selectivity. 13C‐labelling experiments indicated that the formation of acetic acid follows two pathways, the dominant one via oxidation of ethane with preservation of the CC bond, and the other via rupture of this bond and carbonylation of the methyl group by CO; the CC bond is retained in the formation of propionic acid upon carbonylation of ethane. The reactions proceed via both C‐ and O‐centred radicals, as shown by experiments with radical traps. On the basis of detailed DFT calculations, plausible reaction mechanisms are discussed. The carboxylation of ethane in the presence of CO follows the sequential formation of C2H5., C2H5CO., C2H5COO. and C2H5COOH. The C2H5COO. radical is easily formed on reaction of C2H5CO. with a peroxo V catalyst via a V{η1‐OOC(O)C2H5} intermediate. In the absence of CO, carboxylation proceeds by reaction of C2H5. with TFA. For the oxidation of ethane to acetic acid, either with preservation or cleavage of the CC bond, metal‐assisted and purely organic pathways are also proposed and discussed.
Synthesis of chiral vicinal diols and analysis of them by capillary zone electrophoresis
Authors: Liu Peng , He Wei , Zhao Yan , Wang Ping‐An , Sun Xiao‐Li , Li Xiao‐Ye , Zhang Sheng‐Yong 
Published: December 2007

AbstractThis paper describes an improved access to 1,4‐bis (9‐O‐quininyl) phthalazine [(QN)2PHAL], a very useful chiral ligand for catalytic asymmetric dihydroxylation (AD), by using CaH2 as acid‐binding reagent in a high yield under mild conditions. The application of (QN)2PHAL to the AD reactions of eight olefins exhibited excellent enantioselectivity and activity with corresponding chiral vicinal diols. Furthermore, a capillary zone electrophoresis method was developed to separate the aforementioned chiral vicinal diols by using of neutral β‐cyclodextrin (β‐CD) as chiral selector and borate as running buffer. High resolution was achieved under the optimal conditions of β‐CD 2.2% (w/v), pH 10, 200 mM borate buffer at 15 kV, and 20°C within 15 min. The relative standard deviations of the corrected peak areas and migration time were less than 3.9% and 1.3%, respectively. In addition, the developed method was successfully applied to the determination of the purity and the enantiomeric excesses value (%ee) of the AD reaction products. Chirality, 2008. © 2007 Wiley‐Liss, Inc.
The presence of halide salts influences the non‐covalent interaction of MRI contrast agents and human serum albumin
Authors: Henrotte Virginie , Muller Robert N. , Bartholet Annick , Elst Luce Vander 
Published: December 2007

AbstractThe rationale and objectives of the study were to evaluate the influence of the experimental conditions (buffer, salt, etc.) on the data characterizing the non‐covalent interaction between MRI contrast agents and human serum albumin and hence their in vivo relaxivity. The interaction of three gadolinium contrast agents (Gd‐EOB‐DTPA, Gd‐BOPTA and MP‐2269) with human serum albumin was assessed through the measurement of proton relaxation rate enhancement in various experimental conditions. The data show the negative effect of halide salts on the paramagnetic relaxation enhancement of the three contrast agents. The presence of halide salts can thus have a negative effect on the efficacy of MRI contrast agents interacting with HSA. In addition, careful attention must be paid to comparisons of the binding parameters of various contrast agents reported in different studies since the composition of the medium can greatly influence the non‐covalent interaction. Copyright © 2007 John Wiley & Sons, Ltd.
ghrelinis a novel target of Pax4 in endocrine progenitors of the pancreas and duodenum
Authors: Wang Qian , Elghazi Lynda , Martin Sophie , Martins Isabelle , Srinivasan R. Satish , Geng Xin , Sleeman Mark , Collombat Patrick , Houghton Janet , Sosa‐Pineda Beatriz 
Published: December 2007

AbstractPax4‐deficient mice have a severe gastrointestinal endocrine deficiency: they lack most pancreatic cells that produce insulin or somatostatin and various duodenal endocrine cell types. Remarkably,Pax4‐deficient mice also have an overabundance of ghrelin‐expressing cells in the pancreas and duodenum. Detailed analysis of thePax4nullizygous pancreas determined that the mutant islets are largely composed of a distinctive endocrine cell type that expresses ghrelin, glucagon, islet amyloid polypeptide (IAPP), and low levels of Pdx1. Lineage‐tracing analysis revealed that most of these unique endocrine cells directly arose fromPax4‐deficient progenitors. Previous in vitro work reported that Pax4 is a transcriptional repressor ofislet amyloid polypeptide(IAPP) andglucagon. In this study, we expanded those results by showing that Pax4 is also a repressor ofgherlin. Together, our data further support the notion that Pax4 activity is necessary to establish appropriate patterns of gene expression in endocrine progenitors of the digestive tract. Developmental Dynamics 237:51–61, 2008. © 2007 Wiley‐Liss, Inc.
Midkine‐b regulates cell specification at the neural plate border in zebrafish
Authors: Liedtke Daniel , Winkler Christoph 
Published: December 2007

AbstractMidkines compose a family of secreted, heparin‐binding growth factors with neurotrophic activity in vitro, but largely unknown functions in mammals in vivo. Here we show that one member of this family, Midkine‐b (Mdkb), is responsible for establishment of the neural plate border in zebrafish. We propose that MdkB acts downstream of several signaling factors, most notably retinoic acid, implicated in neural crest cell (ncc) induction and refines a zone of competence for ncc and Rohon‐Beard (RB) sensory neuron formation. Overexpression of Mdkb expands the cell numbers of various ncc precursor subtypes and results in a significant increase in the number of RB neurons at the neural plate border. On the other hand, Morpholino‐mediated knockdown of Mdkb leads to a dramatic reduction of ncc and a loss of sensory neurons. Our results imply that Mdkb is required for the earliest steps of cell specification at the neural plate border in zebrafish. Developmental Dynamics 237:62–74, 2008. © 2007 Wiley‐Liss, Inc.
β1 integrin expression on endothelial cells is required for angiogenesis but not for vasculogenesis
Authors: Tanjore Harikrishna , Zeisberg Elisabeth M. , Gerami‐Naini Behzad , Kalluri Raghu 
Published: December 2007

AbstractIntegrins are a family of cell adhesion receptors that are involved in cell–matrix and cell–cell communications. They facilitate cell proliferation, migration, and survival. Using the Cre‐Lox system, we deleted β1 integrin on Tie2‐positive (Tie2‐cre β1 Int fl/fl) vascular endothelial cells. Deletion of β1 integrin on vascular endothelial cells results in embryonic lethality. Blood vessel defects are encountered in the Tie2‐Cre β1 Int fl/fl embryos at embryonic age (E9.5), and embryos die before reaching E10.5. The embryos exhibit growth retardation and both histological evaluation and PECAM‐1 staining of E9.5 embryos revealed defects in angiogenic sprouting and vascular branching morphogenesis. Large and medium‐size vessel formation is not affected in these embryos. Angiogenic defects were observed in several regions of the embryo and yolk sacs. These results indicate that β1 integrin expression on vascular endothelial cells is crucial for embryonic angiogenesis but dispensable for vasculogenesis. Developmental Dynamics 237:75–82, 2008. © 2007 Wiley‐Liss, Inc.
Functional evolutionary history of the mouse Fgf gene family
Authors: Itoh Nobuyuki , Ornitz David M. 
Published: December 2007

AbstractFibroblast Growth Factors (FGFs) are polypeptides with diverse activities in development and physiology. The mammalian Fgf family can be divided into the intracellular Fgf11/12/13/14 subfamily (iFGFs), the hormone‐like Fgf15/21/23 subfamily (hFGFs), and the canonical Fgf subfamilies, including Fgf1/2/5, Fgf3/4/6, Fgf7/10/22, Fgf8/17/18, and Fgf9/16/20. However, all Fgfs are evolutionarily related. We propose that an Fgf13‐like gene is the ancestor of the iFgf subfamily and the most likely evolutionary ancestor of the entire Fgf family. Potential ancestors of the canonical and hFgf subfamilies, Fgf4‐, Fgf5‐, Fgf8‐, Fgf9‐, Fgf10‐, and Fgf15‐like, appear to have derived from an Fgf13‐like ancestral gene. Canonical FGFs function in a paracrine manner, while hFGFs function in an endocrine manner. We conclude that the ancestral Fgfs for these subfamilies acquired this functional diversity before the evolution of vertebrates. During the evolution of early vertebrates, the Fgf subfamilies further expanded to contain three or four members in each subfamily. Developmental Dynamics 237:18–27, 2008. © 2007 Wiley‐Liss, Inc.