bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mimicking Chitin: Chemical Synthesis, Conformational Analysis, and Molecular Recognition of the β(1→3) N‐Acetylchitopentaose Analogue
Authors: Morando Maria , Yao Yanping , Martín‐Santamaría Sonsoles , Zhu Zhenyuan , Xu Tong , Cañada F. Javier , Zhang Yongmin , Jiménez‐Barbero Jesús 
Published: March 2010

AbstractMimicking Nature by using synthetic molecules that resemble natural products may open avenues to key knowledge that is difficult to access by using substances from natural sources. In this context, a novel N‐acetylchitooligosaccharide analogue, β‐1,3‐N‐acetamido‐gluco‐pentasaccharide, has been designed and synthesized by using aminoglucose as the starting material. A phthalic group has been employed as the protecting group of the amine moiety, whereas a thioalkyl was used as the leaving group on the reducing end. The conformational properties of this new molecule have been explored and compared to those of the its chito analogue, with the β‐1,3 linkages, by a combined NMR spectroscopic/molecular modeling approach. Furthermore, the study of its molecular recognition properties towards two proteins, a lectin (wheat germ agglutinin) and one enzyme (a chitinase) have also been performed by using NMR spectroscopy and docking protocols. There are subtle differences in the conformational behavior of the mimetic versus the natural chitooligosaccharide, whereas this mimetic is still recognized by these two proteins and can act as a moderate inhibitor of chitin hydrolysis.
Surfactant‐Stabilized Small Hydrogel Particles in Oil: Hosts for Remarkable Activation of Enzymes in Organic Solvents
Authors: Das Dibyendu , Roy Sangita , Debnath Sisir , Das Prasanta Kumar 
Published: March 2010

AbstractHydrogels of amino acid based cationic surfactant having C16 tails were used to immobilize heme proteins and enzyme. These hydrogel‐entrapped proteins/enzyme showed remarkable activation when dispersed in organic solvent. The activation effect (ratio of the activity of the hydrogel‐entrapped enzyme in organic solvent to the activity of the native enzyme in water) of cytochrome c increased up to 350‐fold with varying protein and gelator concentration. Hydrogel‐entrapped hemoglobin and horseradish peroxidase (HRP) also showed markedly improved activity in organic solvent. Alteration in the structure of the gelator and its supramolecular arrangement showed that the protein immobilized within amphiphilic networks with larger interstitial space exhibited higher activation. This striking activation of hydrogel‐entrapped proteins stems from the following effects: 1) the hydrophilic domain of the amphiphilic networks facilitates accessibility of the enzyme to the water‐soluble substrate. 2) the surfactant, as an integral part of the amphiphilic network, assists in the formation of a distinct interface through which reactants and products are easily transferred between hydrophilic and hydrophobic domains. 3) Surfactant gelators help in the dispersion and stabilization of gel matrix into small particles in organic solvent, which enhances the overall surface area and results in improved mass transfer. The activation was dramatically improved up to 675‐fold in the presence of nongelating anionic surfactants that helped in disintegration of the gel into further smaller‐sized particles. Interestingly, hydrogel‐immobilized HRP exhibited about 2000‐fold higher activity in comparison to the activity of the suspended enzyme in toluene. Structural changes of the entrapped enzyme and the morphology of the matrix were investigated to understand the mechanism of this activation.
Adaptative Biaryl Phosphite–Oxazole and Phosphite–Thiazole Ligands for Asymmetric Ir‐Catalyzed Hydrogenation of Alkenes
Authors: Mazuela Javier , Paptchikhine Alexander , Pàmies Oscar , Andersson Pher G. , Diéguez Montserrat 
Published: March 2010

AbstractA library of readily available phosphite–oxazole/thiazole ligands (L1 a–g–L7 a–g) was applied in the Ir‐catalyzed asymmetric hydrogenation of several largely unfunctionalized E‐ and Z‐trisubstituted and 1,1‐disubstituted terminal alkenes. The ability of the catalysts to transfer chiral information to the product could be tuned by choosing suitable ligand components (bridge length, the substituents in the heterocyclic ring and the alkyl backbone chain, the configuration of the ligand backbone, and the substituents/configurations in the biaryl phosphite moiety), so that enantioselectivities could be maximized for each substrate as required. Enantioselectivities were therefore excellent (enantiomeric excess (ee) values up to >99 %) for a wide range of E‐ and Z‐trisubstituted and 1,1‐disubstituted terminal alkenes. The biaryl phosphite moiety was a very advantageous ligand component in terms of substrate versatility.
Signal‐regulated systems and networks
Authors: van Zyl Terence L. , Ehlers Elizabeth M. 
Published: March 2010

AbstractThe article presents the use of signal regulatory networks (SRNs), a biologically inspired model based on gene regulatory networks. SRNs are a way of understanding a class of self‐organizing IT systems, signal‐regulated systems (SRSs). This article builds on the theory of SRSs and introduces some formalisms to clarify the discussion. An exemplar SRS that can be evaluated using SRNs is presented. Finally, an implementation of an adaptive and robust solution, built on a theory of SRSs and analyzed as a SRN, is shown to be plausible. © 2010 Wiley Periodicals, Inc. Complexity, 2010
Evaluation of apoptosis in cytologic specimens
Authors: Shtilbans Viktor , Wu Maoxin , Burstein David E. 
Published: March 2010

AbstractA hallmark of neoplasia is dysregulated apoptosis, programmed cell death. Apoptosis is crucial for normal tissue homeostasis. Dysregulation of apoptotic pathways leads to reduced cytocidal responses to chemotherapeutic drugs or radiation and is a frequent contributor to therapeutic resistance in cancer. The literature pertaining to detection of apoptotic pathway constituents in cytologic specimens is reviewed herein. Virtually all methods for detecting apoptosis, including classic cytomorphologic evaluation, TUNEL assay, immunocytochemistry, and gene sequence analysis, may be applied to cytologic samples as well as tissue. Components of both intrinsic and extrinsic apoptotic pathways have been studied, including many reports examining p53 and bcl‐2, as well as studies of caspase inhibitory proteins XIAP and survivin, death receptors and ligands such as Fas, Fas‐ligand, and TRAIL. p53 undergoes oncogenic alteration more than any other protein; its immunocytochemical detection almost always connotes loss of its physiologic role as an inducer of apoptosis in response to a damaged genome. Several reports establish cytologic sampling as being as useful as tissue sampling. In one respect cytologic sampling is superior to tissue sampling in particular, by allowing clinicians to repeat sampling of the same tumor before and after administration of therapy; a number of reports use this approach to attempt to predict tumor response by assaying the effect of chemotherapy on the induction of apoptosis. Diagn. Cytopathol. 2010;38:685–697. © 2010 Wiley‐Liss, Inc.
Identification and characterization of the n‐6 fatty acid‐producing Mucor rouxii native isolate CFR‐G15
Authors: Mamatha Shivaramu S. , Halami Prakash M. , Venkateswaran Govindarajulu 
Published: March 2010

AbstractIn zygomycetes fungi, many Mucor spp. have been known to produce γ‐linolenic acid (GLA) in their biomass. Among 250 soil samples screened, 20 Mucor isolates showed GLA in their mycelial mass under normal cultivation conditions. Sudan Black B was used for screening their qualitative oleaginesity. Among the representative isolates, Mucor sp. CFR‐G15, when grown in a fat‐producing medium, showed a maximum lipid content of 30 ± 1.32% in its mycelia and 14.42 ± 0.74% GLA. By using gene‐specific primers, the 18S rRNA gene and the Δ6 DES gene were amplified by PCR technique. The nucleotide sequences of the 18S rRNA and Δ6 DES genes exhibited >98% homology with M. rouxii ATCC 24905 (accession nos. AF117923 and AF296076, respectively), suggesting taxonomic identity. The native isolate M. rouxii CFR‐G15 reported in this study was found to be promising for the development of an economical process in the industrial production of GLA.
Flux schemes based finite volume method for internal transonic flow with condensation
Authors: Halama J. , Benkhaldoun F. , Fořt J. 
Published: March 2010

AbstractThis paper describes the development of numerical method for the solution of condensing steam flow in internal aerodynamics problems. The numerical method is based on the fractional step method, where the resulting set of ODEs is solved by the two‐stage Runge–Kutta method and the homogeneous set of PDEs by a finite volume method. The flow does not contain both phases (gas and liquid) in the whole domain, therefore we discuss properties of used finite volume methods in several cases of single‐phase transonic flow in a channel and a turbine cascade. We present numerical results of two‐phase flow of condensing steam in 2D nozzle achieved by several numerical methods and show the differences in results caused by numerical diffusion. Copyright © 2010 John Wiley & Sons, Ltd.
Summing nondetects: Incorporating low-level contaminants in risk assessment
Authors: Helsel Dennis R 
Published: March 2010

Abstract
Low-level contaminants often are present below the detection or reporting limits of a laboratory, resulting in values reported as a nondetect or less-than. How can these values be summed along with detected concentrations to obtain a total, particularly when weighting factors such as toxic equivalence factors (TEFs) are used? The most common method employed by environmental scientists for summing nondetects along with detected values is to substitute one-half the detection limit for each nondetect. This substitution allows the least precise measurements, data with high detection limits, to have a strong influence on the resulting total amount. Substitution methods have repeatedly been shown to provide substandard results in studies over the last 2 decades. Here an alternative, the Kaplan–Meier (KM) method used throughout the fields of medical and industrial statistics, is used to obtain the total. KM estimates are far less affected by the least precise data than are estimates computed using substitution. No assumptions about the distribution of data (whether they follow a normal or other distribution) need be made. Direct application of KM to computation of toxicity equivalence concentrations (TECs) is shown. Integr Environ Assess Manag 2010;6:361–366. © 2009 SETAC
Are endocrine disruptors among the causes of the deterioration of aquatic biodiversity?
Authors: Zhou Jin , Cai Zhong-Hua , Zhu Xiao-Shan 
Published: March 2010

Abstract
Exposure to environmental pollutants such as endocrine-disrupting compounds (EDCs) is now taken into account to explain partially the biodiversity decline of aquatic ecosystems. Much research has demonstrated that EDCs can adversely affect the endocrine system, reproductive health, and immune function in aquatic species. These toxicological effects include 1) interference with normal hormonal synthesis, release, and transport, 2) impairment of growth, development, and gonadal maturation, and 3) increased sensitivity to environmental stressors. Recent studies also have confirmed that EDCs have carcinogenic and mutagenic potential. In essence, these changes in physiological and biochemical parameters reflect, to some extent, some phenotypic characteristics of the deterioration of aquatic biodiversity. At present, evidence at the molecular level shows that exposure to EDCs can trigger genotoxicity, such as DNA damage, and can reduce genetic diversity. Field studies have also provided more direct evidence that EDCs contribute to the population decrease and biodiversity decline. Evolutionary toxicology and multigenerational toxicity tests have further demonstrated that EDCs can damage an organism's offspring and eventually likely lead to loss of evolutionary potential. Taken together, these results provide some basis for understanding the relationship between variety deterioration and EDC exposure. It is conceivable that there is a causal association between EDC exposure and variety deterioration of aquatic organisms. Integr Environ Assess Manag 2010;6:492–498. © 2010 SETAC
Regulatory aspects on the use of fish embryos in environmental toxicology
Authors: Halder Marlies , Léonard Marc , Iguchi Taisen , Oris James T , Ryder Kathy , Belanger Scott E , Braunbeck Thomas A , Embry Michelle R , Whale Graham , Norberg-King Teresa , Lillicrap Adam 
Published: March 2010

Abstract
Animal alternative tests are gaining serious consideration in an array of environmental sciences, particuarly as they relate to sound management of chemicals and wastewater discharges. The ILSI Health and Environmental Sciences Institute and the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) held an International Workshop on the Application of the Fish Embryo Test in March, 2008. This relatively young discipline is following advances in animal alternatives for human safety sciences, and it is advisable to develop a broad comparison of how animal alternative tests involving fish are viewed in a regulatory context over a wide array of authorities or advising bodies. These include OECD, Western Europe, North America, and Japan. This paper summarizes representative practices from these regions. Presently, the global regulatory environment has varying stances regarding the protection of fish for use as an experimental animal. Such differences have a long-term potential to lead to a lack of harmony in approaches to fish toxicity testing, especially for chemicals in commerce across multiple geographic regions. Implementation of alternative methods and approaches will be most successful if accepted globally, including methods of fish toxicity testing. An important area for harmonization would be in the interpretation of protected and nonprotected life stages of fish. Use of fish embryos represent a promising alternative and allow bridging to more technically challenging alternatives with longer prospective timelines, including cell-based assays, ecotoxicogenomics, and QSARs. Integr Environ Assess Manag 2010;6:484–491. © 2010 SETAC
The european union risk assessment on zinc and zinc compounds: The process and the facts
Authors: Bodar Charles W.M. , Pronk Marja E.J. , Sijm Dick T.H.M. 
Published: March 2010

Abstract
A risk assessment on zinc and zinc compounds was carried out within the framework of Council Regulation 793/93/EEC on Existing Chemicals. This risk assessment basically followed the European Union (EU) technical guidance documents (TGDs). These TGDs are built on the current knowledge on quantitative risk assessments, mainly for organic chemicals. This article describes the tailor-made approach for the zinc risk assessment. This work lasted almost a decade and involved the contributions of all EU member states and industry, who discussed the risk assessment during technical meetings. The risk assessment is initially based on scientific findings but is interrelated with pragmatic considerations. It follows a comprehensive approach, covering both environmental and human health. In the environmental part, new methodologies were developed to deal with the natural background of zinc, essentiality, speciation, and the use of species sensitivity distributions. The major results and the process of drawing conclusions of the risk assessment are outlined: potential environmental risks of zinc and zinc compounds may occur at local and regional scales in surfacewater, sediment, and soil. No potential health risks were identified for consumers and man indirectly exposed via the environment. For workers, potential health risks were identified only for zinc oxide and zinc chloride.
Methamidophos, dichlorvos, O‐methoate and diazinon pesticides used in Turkey make a covalent bond with butyrylcholinesterase detected by mass spectrometry
Authors: Tacal Ozden , Lockridge Oksana 
Published: March 2010

AbstractOrganophosphorus pesticides used most commonly in Turkey include methamidophos, dichlorvos, O‐methoate and diazinon. These toxic chemicals or their metabolites make a covalent bond with the active site serine of butyrylcholinesterase. Our goal was to identify the adducts that result from the reaction of human butyrylcholinesterase with these pesticides. Highly purified human butyrylcholinesterase was treated with a 20‐fold molar excess of pesticide. The protein was denatured by boiling and digested with trypsin. MS and MSMS spectra of HPLC‐purified peptides were acquired on a MALDI‐TOF‐TOF 4800 mass spectrometer. It was found that methamidophos added a mass of +93, consistent with addition of methoxy aminophosphate. A minor amount of adduct with an added mass of +109 was also found. Dichlorvos and O‐methoate both made dimethoxyphosphate (+108) and monomethoxyphosphate adducts (+94). Diazinon gave a novel adduct with an added mass of +152 consistent with diethoxythiophosphate. Inhibition of enzyme activity in the presence of diazinon developed slowly (15 h), concomitant with isomerization of diazinon via a thiono‐thiolo rearrangement. The isomer of diazinon yielded diethoxyphosphate and monoethoxyphosphate adducts with added masses of +136 and +108. MSMS spectra confirmed that each of the pesticides studied made a covalent bond with serine 198 of butyrylcholinesterase. These results can be used to identify the class of pesticides to which a patient was exposed.
A comprehensive review of surface modification for neural cell adhesion and patterning
Authors: Khan Saida , Newaz Golam 
Published: March 2010

AbstractThis comprehensive literature review covers recent studies on patterning neuronal cells by topographical modifications on material surfaces targeted for neural prostheses. We explore different materials that are used as the candidate surface for neuronal cell adhesion. Cell–material interactions are identified in both cases where the material surface was in direct contact with cells and where the materials were coated to facilitate cell adhesion. Commonly used coating materials and coating methods are discussed. The existing hypotheses behind mechanism of the response of neuronal cells to a specific topography are presented briefly. A few selected important studies have been presented to show the range of techniques employed and the extent of the research area. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
In vivo testing of a biodegradable woven fabric made of bioactive glass fibers and PLGA80—A pilot study in the rabbit
Authors: Alm Jessica J. , Frantzén Janek P. A. , Moritz Niko , Lankinen Petteri , Tukiainen Mikko , Kellomäki Minna , Aro Hannu T. 
Published: March 2010

AbstractThe purpose of this study was to perform an intra‐animal comparison of biodegradable woven fabrics made of bioactive glass (BG) fibers and poly(L‐lactide‐co‐glycolide) 80/20 copolymer (PLGA80) fibers or PLGA80 fibers alone, in surgical stabilization of bone graft. The BG fibers (BG 1‐98) were aimed to enhance bone growth at site of bone grafting, whereas the PLGA component was intended to provide structural strength and flexibility to the fabric. Bone formation was analyzed qualitatively by histology and quantitatively by peripheral quantitative computed tomography (pQCT) at 12 weeks. The surgical handling properties of the control PLGA80 fabric were more favorable. Both fabrics were integrated with the cortical bone surfaces, but BG fibers showed almost complete resorption. There were no signs of adverse local tissue reactions. As a proof of material integration and induced new bone formation, there was a significant increase in bone volume of the operated femurs compared with the contralateral intact bone (25% with BG/PLGA80 fabric, p < 0.001 and 28% with the control PLGA80 fabric, p = 0.006). This study failed to demonstrate the previously seen positive effect of BG 1‐98 on osteogenesis, probably due to the changed resorption properties of BG in the form of fibers. Therefore, the feasibility and safety of BG as fibers needs to be reevaluated before use in clinical applications. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Modeling of maximum dry density and optimum moisture content of stabilized soil using artificial neural networks
Authors: Hossein Alavi Amir , Hossein Gandomi Amir , Mollahassani Ali , Akbar Heshmati Ali , Rashed Azadeh 
Published: March 2010

AbstractThis study considers the use of artificial neural networks (ANNs) to predict the maximum dry density (MDD) and optimum moisture content (OMC) of soil‐stabilizer mix. Multilayer perceptron (MLP), one of the most widely used ANN architectures in the literature, is utilized to construct comprehensive and accurate models relating the MDD and OMC of stabilized soil to the properties of natural soil such as particle‐size distribution, plasticity, linear shrinkage, and the type and quantity of stabilizing additives. Five ANN models are constructed using different combinations of the input parameters. Two separate sets of ANN prediction models, one for MDD and the other for OMC, and also a combined ANN model for multiple outputs are developed using the potentially influential input parameters. Relative‐importance values of various inputs of the models are calculated to determine the significance of each of the predictor variables to MDD and OMC. Inferring the most relevant input parameters based on Garson's algorithm, modified ANN models are separately developed for MDD and OMC. The modified ANN models are utilized to introduce explicit formulations of MDD and OMC. A parametric study is also conducted to evaluate the sensitivity of MDD and OMC due to the variation of the most influencing input parameters. A comprehensive set of data including a wide range of soil types obtained from the previously published stabilization test results is used for training and testing the prediction models. The performance of ANN‐based models is subsequently analyzed and compared in detail. The results demonstrate that the accuracy of the proposed models is satisfactory as compared to the experimental results.
Organometallic Complexes for Nonlinear Optics, 47 – Synthesis and Cubic Optical Nonlinearity of a Stilbenylethynylruthenium Dendrimer
Authors: Jeffery Christopher J. , Cifuentes Marie P. , Dalton Gulliver T. , Corkery T. Christopher , Randles Michael D. , Willis Anthony C. , Samoc Marek , Humphrey Mark G. 
Published: March 2010

AbstractThe synthesis of the 1st generation dendrimer 1,3,5‐{trans‐[Ru(C≡C‐3,5‐(trans‐[Ru(C≡CPh)(dppe)2(C≡CC6H4‐4‐(E)‐CHCH)])2C6H3)(dppe)2(C≡CC6H4‐4‐(E)‐CHCH)]}3C6H3 proceeds by a novel route that features Emmons‐Horner‐Wadsworth coupling of 1,3,5‐C6H3(CH2PO(OEt)2)3 with trans‐[Ru(C≡CC6H4‐4‐CHO)Cl(dppe)2] and 1‐I‐C6H3‐3,5‐(CH2PO(OEt)2)2 with trans‐[Ru(C≡CPh)(C≡CC6H4‐4‐CHO)(dppe)2] as key steps. The stilbenylethynylruthenium dendrimer is much more soluble than its ethynylated analog 1,3,5‐{trans‐[Ru(C≡C‐3,5‐(trans‐[Ru(C≡CPh)(dppe)2(C≡CC6H4‐4‐C≡C)])2C6H3)(dppe)2(C≡CC6H4‐4‐C≡C)]}3C6H3 and, in contrast to the ethynylated analog, is a two‐photon absorber at telecommunications wavelengths.magnified image