bluuebunny/crossref_metadata_2025_split huggingface dataset:
Disruption of Topoisomerase II Perturbs Pairing in Drosophila Cell Culture
Authors: Williams Benjamin R , Bateman Jack R , Novikov Natasha D , Wu C-Ting 
Published: September 2007

AbstractHomolog pairing refers to the alignment and physical apposition of homologous chromosomal segments. Although commonly observed during meiosis, homolog pairing also occurs in nonmeiotic cells of several organisms, including humans and Drosophila. The mechanism underlying nonmeiotic pairing, however, remains largely unknown. Here, we explore the use of established Drosophila cell lines for the analysis of pairing in somatic cells. Using fluorescent in situ hybridization (FISH), we assayed pairing at nine regions scattered throughout the genome of Kc167 cells, observing high levels of homolog pairing at all six euchromatic regions assayed and variably lower levels in regions in or near centromeric heterochromatin. We have also observed extensive pairing in six additional cell lines representing different tissues of origin, different ploidies, and two different species, demonstrating homolog pairing in cell culture to be impervious to cell type or culture history. Furthermore, by sorting Kc167 cells into G1, S, and G2 subpopulations, we show that even progression through these stages of the cell cycle does not significantly change pairing levels. Finally, our data indicate that disrupting Drosophila topoisomerase II (Top2) gene function with RNAi and chemical inhibitors perturbs homolog pairing, suggesting Top2 to be a gene important for pairing.
Purification and Localization of Nitric Oxide Synthases from Hybrid Tilapia (Nile Tilapia × Mozambique Tilapia)
Authors: Wang Way-Shyan , Hung Shao-Wen , Lin Yu-Hsing , Tu Ching-Yu , Wong Min-Liang , Chiou Shiow-Her , Shieh Meng-Tong 
Published: September 2007

Abstract
The aims of this study were to purify and localize the nitric oxide synthases (NOSs) from hybrid tilapia (Nile tilapia Oreochromis niloticus × Mozambique tilapia O. mossambicus). The purification procedures involved affinity chromatography with a 2′, 5′-ADP-agarose 4B column and ion exchange with a diethylaminoethanol Bio-Gel A column. The results from gel filtration assays showed that the molecular weights of neuronal NOS (nNOS) and inducible NOS (iNOS) were 178 and 120 kDa, respectively. The sodium dodecyl sulfate–polyacrylamide gel electrophoresis results showed that there were three bands with molecular weights of 89, 47, and 29 kDa from the purified nNOS. However, only one band, with a molecular weight of 120 kDa, appeared on the gel from the purified iNOS. Hybrid tilapia nNOS was a dimer structure, while iNOS appeared to be a monomer structure. Moreover, our results revealed that the activities of nNOS and iNOS were significantly higher after the addition of Ca+2 or Mg+2 ions individually. However, when l-arginine and NADPH were present, the addition of 1 mM of either ion did not further increase the activity. The chemical l-NG-methyl-l-arginine could inhibit the activities of the purified NOSs with or without l-arginine. Western blot analyses showed only an 89-kDa immunoreactive band from the extracts of cerebrum; however, we did not find the specific bands in other tissues, such as gill, intestine, liver, spleen, and anterior kidney. We found another 120-kDa immunoreactive protein band with the rabbit antirat iNOS serum against iNOS from the extracts of anterior kidney and spleen. The results of immunohistochemistry with the rabbit antihuman nNOS serum indicated that the nNOS existed in the cerebellum, olfactory bulb, diencephalons, and nerve cell bodies and neuronal fibers of the spinal cord. Interestingly, only macrophages from anterior kidney and spleen showed positive reactions with the rabbit antirat iNOS serum. In the same way, the endothelial NOS (eNOS) located in the heart and epithelial cells of the blood vessels reacted positively with the rabbit antibovine eNOS serum.
Use of Eyeballs for Establishing Ploidy of Asian Carp
Authors: Jenkins Jill A. , Thomas R. Glenn 
Published: September 2007

Abstract
Grass carp Ctenopharyngodon idella, silver carp Hypophthalmichthys molitrix, and bighead carp H. nobilis are now established and relatively common in the Mississippi and Atchafalaya rivers. Commercial fishers of Louisiana's large rivers report recurrent catches of grass carp, and the frequency of bighead carp and silver carp catch is increasing. Twelve black carp Mylopharyngodon piceus were recently captured from the Mississippi and Atchafalaya River system, and 10 were analyzed for ploidy. By using the methods described herein, all 10 fish were determined to be diploid. Such correct identifications of ploidy of feral Asian carp species, as well as other species, would provide science-based information constructive for meeting reporting requirements, tracking fish movements, and forecasting expansion of species distribution. To investigate the postmortem period for sample collection and to lessen demands on field operations for obtaining samples, a laboratory study was performed to determine the length of time for which eyeballs from postmortem black carp could be used for ploidy determinations. Acquiring eyes rather than blood is simpler and quicker and requires no special supplies. An internal DNA reference standard with a documented genome size, including erythrocytes from diploid black carp or Nile tilapia Oreochromis niloticus, was analyzed simultaneously with cells from seven known triploid black carp to assess ploidy through 12 d after extraction. Ploidy determinations were reliable through 8 d postmortem. The field process entails excision of an eyeball, storage in a physiological buffer, and shipment within 8 d at refrigeration temperatures (4°C) to the laboratory for analysis by flow cytometry.
Differentiation and Enrichment of Hepatocyte-Like Cells from Human Embryonic Stem Cells In Vitro and In Vivo
Authors: Duan Yuyou , Catana Andreea , Meng Ying , Yamamoto Naoki , He Songqing , Gupta Sanjeev , Gambhir Sanjiv Sam , Zern Mark A. 
Published: September 2007

Abstract
Human embryonic stem cells (hESC) may provide a cell source for functional hepatocytes. The aim of this study is to establish a viable human hepatocyte-like cell line from hESC that can be used for cell-based therapies. The differentiated hESC were enriched by transducing with a lentivirus vector containing the green fluorescent protein (GFP) gene driven by the α1-antitrypsin promoter; the GFP gene is expressed in committed hepatocyte progenitors and hepatocytes. GFP+ hESC were purified by laser microdissection and pressure catapulting. In addition, differentiated hESC that were transduced with a lentivirus triple-fusion vector were transplanted into NOD-SCID mice, and the luciferase-induced bioluminescence in the livers was evaluated by a charge-coupled device camera. GFP+ hESC expressed a large series of liver-specific genes, and expression levels of these genes were significantly improved by purifying GFP+ hESC; our results demonstrated that purified differentiated hESC express nearly physiological levels of liver-specific genes and have liver-specific functions that are comparable to those of primary human hepatocytes. The differentiated hESC survived and engrafted in mouse livers, and human liver-specific mRNA and protein species were detected in the transplanted mouse liver and serum at 3 weeks after transplantation. This is the first time that human albumin generated by hESC-derived hepatocytes was detected in the serum of an animal model. This also represents the first successful transplantation of differentiated hESC in an animal liver and the first bioluminescence imaging of hESC in the liver. This study is an initial step in establishing a viable hepatocyte-like cell line from hESC.
Disclosure of potential conflicts of interest is found at the end of this article.
Exergoecological analysis of processing of SO2-containing gases from zinc production
Authors: Patronov G. , Magaeva S. 
Published: September 2007

AbstractAn energy and technological study of processing SO2-containing metallurgical gases from zinc production to sulfuric acid production using the exergy method of thermodynamic analysis has bean carried out. A real operating installation since 2003 at the KCM-SA, Plovdiv, Bulgaria, has been used as the model scheme. The principal production stages have been analyzed. The absolute and the relative exergy characteristics of the separate stages as well as of the process as a whole have been calculated. The results have been used to evaluate the influence of sulfuric acid production on the environment. The results obtained have been compared with previous studies on similar processes both in zinc and in copper production. The studied installation of sulfuric acid production has good exergoecological indices, defining it as an effective process both in thermotechnical and in ecological aspects.
Study of controlled tetracycline release from porous calcium phosphate/polyhydroxybutyrate composites
Authors: Medvecký L’ , Štulajterová R. , Briančin J. 
Published: September 2007

AbstractPorous calcium phosphate ceramics were prepared by sintering of mixtures of nanocrystalline apatitic calcium phosphate and fibrous natural cotton cellulose after pressing at temperatures of 1150 °C and 1250 °C. Micro-and macropores were present in microstructures of ceramic samples. The microstructures of porous ceramics were similar to those observed in bone tissues and fiber-like randomly oriented texture was observed in ceramics. Polyhydroxybutyrate (PHB) biopolymer layers are distributed homogeneously in the samples after evaporation of the diluent (chloroform) from the PHB vacuum impregnated porous samples. The tetracycline (TTC) release rate decreases with the content of polyhydroxybutyrate in the ceramic samples, which corresponds to the rise in amount of biopolymer displaced in the pores of ceramics. The concentration of TTC in the phosphate buffer saline solution varies almost linearly with time after the first seven hours from the start of the release of the calcium phosphate ceramic samples with 2.4 mass % of polyhydroxybutyrate. The initial burst effect was significantly depressed by the preparation method used.
Excess molar volumes of the (cyclohexane + pentane, or hexane, or heptane, or octane, or nonane) systems at the temperature 298.15 K
Authors: Balán J. , Morávková L. , Linek J. 
Published: September 2007

AbstractThe densities of the (cyclohexane + pentane, or hexane, or heptane, or octane, or nonane) systems were measured at the temperature 298.15 K by means of a vibrating-tube densimeter. Their respective excess molar volumes were calculated and correlated using the fourth-order Redlich—Kister equation, with the maximum likelihood principle being applied in the determination of the adjustable parameters. The values of excess molar volumes were negative for the cyclohexane + pentane system, whereas they were positive for the other systems with the values increasing with the number of carbon atoms in the respective alkane molecules.
Solid-state vibrational spectra and theoretical study of alaninamide acetate
Authors: Kolev T. 
Published: September 2007

AbstractSolid-state IR and Raman spectroscopic elucidation of alaninamide acetate is preformed by means of the possibilities of linear-polarized IR and Raman methods. The experimental assignment is compared with theoretical vibrational analysis with the intention to explain the influence of intermolecular interactions in solid phase on the spectroscopic properties of the compound studied. The 1H and 13C NMR spectra in solution are compared with the corresponding ones of alanine, studying the amidation effect on the chemical shift signals in the alanine moieties.
Synthesis and antifungal activity of alkyland arylsulfanylpyridinylguanidines
Authors: Palát K. , Braunerová G. , Miletín M. , Buchta V. 
Published: September 2007

AbstractA series of alkyl- and arylsulfanylpyridylguanidines was synthesized and their antimicrobial activity was evaluated in vitro against eight potentially pathogenic strains of fungi. Compounds with an alkylsulfanyl substitution have antifungal activity, which improves with increasing length of the aliphatic chain.
Isolation and identification of flower oil components from four Staphylea L. species
Authors: Laciková L’. , Švajdlenka E. , Mašterová I. , Grančai D. 
Published: September 2007

AbstractChemical composition of the hydrodistilled volatile fraction from flowers of four Staphylea L. species (Staphylea colchica Stev., Staphylea elegans Zab., Staphylea holocarpa Hemsl., Staphylea pinnata L.) was determined by the GC/MS method. Compounds in fresh and dried flowers (stored for 1 year) were determined. Mostly, structures of different oxygenated aliphatic hydrocarbons in all four species were found. Different aldehydes, ketones, esters of higher fatty acids, and hexadecanoic acid were identified, with dominating content of tricosane, hexadecanoic acid and also of heneicosane, pentacosane, heptacosane, and nonacosane. In S. pinnata L. (fresh flowers) some nonaliphatic hydrocarbons, and in S. holocarpa Hemsl. (fresh flowers) esters of higher fatty acids were found.
Mechanical Properties and Environmental Behavior of a Magnesium Alloy with a Nano‐/Sub‐Micron Structure
Authors: Aghion E. , Arnon A. 
Published: September 2007

AbstractNewly developed magnesium alloys with a consolidated nano/sub‐micron structure and substantially higher specific strength may be considered as an interesting candidate for super‐light high‐strength applications. Consolidated nano/sub‐micron structure applies to alloys with a combined microstructure of nano‐crystalline and sub‐micron grains. The aim of the present study was to explore the mechanical and environmental behavior of a consolidated nano/sub‐micron magnesium alloy with the composition of AZ31. This was required in order to evaluate the applicability of this new structured alloy for practical applications. Although the nano/sub‐micron structured alloy has more than twice the hardness and strength of the conventional alloy, its ductility and corrosion resistance were significantly lower. In addition, its stress corrosion characteristics were inferior. The significant limitation of the nano‐structured alloy, in terms of ductility and corrosion performance, restricts its potential use as a structural material for practical applications.
Thermodynamic Simulation of Phase Formation During Blending of Mg‐Alloys by Thixomolding
Authors: Kozlov A. , Djurdjevic M. , Schmid‐Fetzer R. 
Published: September 2007

AbstractThixomolding, as a semisolid processing approach, offers a unique opportunity to produce new Mg‐alloys by mixing different feedstock chips at room temperature. This way of blending or mixing two or more commercially available standard Mg alloys will produce a new alloy with different melting range, solidification path, phase distribution and metallurgical and mechanical properties. This paper demonstrates the applicability of thermodynamic modeling to generate detailed information about phase formation in thixomolding process. For this purpose the process is pictured by appropriate thermodynamic calculations using a multicomponent Mg alloy database.
A New Analytical Approach to Reveal the Mechanisms of Grain Refinement
Authors: StJohn D. H. , Cao P. , Qian M. , Easton M. A. 
Published: September 2007

AbstractThis paper presents an overview of a new methodology for investigating the grain refinement performance of alloys and master alloys and then uses this methodology to shed new light on the mechanisms occurring during superheating and native grain refinement, and the effect of iron and manganese on grain refinement in magnesium alloys. The methodology also describes changes in grain size upon Zr grain refinement of Mg and has been used to analyse the potential for the use of SiC to grain refine Mg‐Al alloys. With this new methodology, and the knowledge it generates, the potential for the discovery of new or improved refiners is significantly enhanced.
Hydrolytically Stable Phosphorylated Hybrid Silicas for Proton Conduction
Authors: Jin Y. G. , Qiao S. Z. , da Costa J. C. D. , Wood B. J. , Ladewig B. P. , Lu G. Q. 
Published: September 2007

AbstractA new approach to the synthesis of fully immobilized phosphorus functionalized hybrid proton conductive gels based on phosphonic acid grafting is presented in this paper. The hybrid silicas with different amounts of phosphonic acid have been prepared and characterized using Fourier‐transform infrared spectroscopy, X‐ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area analysis, thermogravimetric analysis, and electrochemical techniques. The proton conductivity of the materials depend strongly on hydration, which increases by four orders of magnitude over the relative humidity (RH) range of 20 to 100 %, up to a maximum of 0.027 S cm–1 at 100  °C and 100 % RH. For the reported samples, proton conduction is believed to occur within a dynamic hydrogen‐bond network formed by functionalized P–OH groups and water molecules by the Grotthuss mechanism. However, the proton conductive sites (P–OH) are likely to be partially immobilized by strong protonic receptors (N atoms in amines), which reduces the free P–OH groups and restricts proton transfer. Hydration may cause a bonding structural rearrangement, which results in more free P–OH groups as active proton conductive sites and, therefore, greatly increased proton conductivity is observed.
Soluble Phenanthrenyl‐Imidazole‐Presenting Regioregular Poly(3‐octylthiophene) Copolymers Having Tunable Bandgaps for Solar Cell Applications
Authors: Chang Y.‐T. , Hsu S.‐L. , Su M.‐H. , Wei K.‐H. 
Published: September 2007

AbstractWe have used Grignard metathesis polymerization to successfully synthesize a series of regioregular polythiophene copolymers that contain electron‐withdrawing and conjugated phenanthrenyl‐imidazole moieties as side chains. The introduction of the phenanthrenyl‐imidazole moieties onto the side chains of the regioregular polythiophenes increased their conjugation lengths and thermal stabilities and altered their bandgap structures. The bandgap energies, determined from the onset of optical absorption, could be tuned from 1.89 eV to 1.77 eV by controlling the number of phenanthrenyl‐imidazole moieties in the copolymers. Moreover, the observed quenching in the photoluminescence of these copolymers increases with the number of phenanthrenyl‐imidazole moieties in the copolymers, owing to the fast deactivation of the excited state by the electron‐transfer reaction. Both the lowered bandgap and fast charge transfer contribute to the much higher external quantum efficiency of the poly(3‐octylthiophene)‐side‐chain‐tethered phenanthrenyl‐imidazole than that of pure poly(3‐octylthiophene), leading to much higher short circuit current density. In particular, the short circuit current densities of the device containing the copolymer having 80 mol % phenanthrenyl‐imidazole, P82, improved to 14.2 mA cm–2 from 8.7 mA cm–2 for the device of pure poly(3‐octylthiophene), P00, an increase of 62 %. In addition, the maximum power conversion efficiency improves to 2.80 % for P82 from 1.22 % for P00 (pure P3OT). Therefore, these results indicate that our polymers are promising polymer photovoltaic materials.
Thermosensitive Nanostructures Comprising Gold Nanoparticles Grafted with Block Copolymers
Authors: Li D. , Cui Y. , Wang K. , He Q. , Yan X. , Li J. 
Published: September 2007

AbstractBinary thermosensitive nanocomposites are fabricated by grafting block copolymers of poly(N‐isopropylacrylamide) and poly(methoxy‐oligo(ethylene glycol) methacrylate) onto gold nanoparticles through consecutive, surface‐initiated, atom‐transfer radical polymerization (ATRP). These Au@copolymer nanocomposites display a well‐defined core/shell nanostructure and have two thermosensitive points near 33 and 55 °C in an aqueous suspension corresponding to the thermally induced conformational transition of inner homopolymer segments and outer oligo(ethylene glycol)‐containing copolymer layer, respectively. Silver nanoparticles trapped within Au@copolymer nanocomposites with weakly crosslinked shells display thermally modulated catalytic activity as heterogeneous catalysts because of the thermosensitive collapse of the polymer layers.
Investigation on the Low Luminous Efficiency in a Polymer Light‐Emitting Diode with a High Work‐function Cathode by Soft Contact Lamination**
Authors: Lee T.‐W. 
Published: September 2007

AbstractThis article reports the main origin of the low luminescent efficiency in hole‐dominant polymer light‐emitting diodes by controlling the hole injection and by chemically modifying the cathode by molecular monolayers. Since molecular modification of the top electrode is impossible when one deposits the electrode using a vacuum deposition method, this study was performed using a soft contact lamination technique to form electrical contacts on top of the emissive layer. The top electrode was chemically modified with an alkane thiol self‐assembled monolayer (SAM) to act as an interfacial spacer layer between the emitting layer and the cathode. Herein, it is reported that, contrary to common belief, a high device quantum efficiency can be achieved from the dominantly hole‐transporting device with a high work‐function cathode (like Au) by facilitating more hole injection from the anode in the device with low population of exciton quenching channels near the cathode.
An exploratory study of the relationship between four candidate genes and neurocognitive performance in adult ADHD
Authors: Boonstra A. Marije , Kooij J.J. Sandra , Buitelaar Jan K. , Oosterlaan Jaap , Sergeant Joseph A. , Heister J.G.A.M. Angelien , Franke Barbara 
Published: September 2007

AbstractSince neurocognitive performance is a possible endophenotype for Attention Deficit Hyperactivity Disorder (ADHD) we explored the relationship between four genetic polymorphisms and neurocognitive performance in adults with ADHD. We genotyped a sample of 45 adults with ADHD at four candidate polymorphisms for the disorder (DRD4 48 base pair (bp) repeat, DRD4 120 bp duplicated repeat, SLC6A3 (DAT1) 40 bp variable number of tandem repeats (VNTR), and COMT Val158Met). We then sub‐grouped the sample for each polymorphism by genotype or by the presence of the (putative) ADHD risk allele and compared the performance of the subgroups on a large battery of neurocognitive tests. The COMT Val158Met polymorphism was related to differences in IQ and reaction time, both of the DRD4 polymorphisms (48 bp repeat and 120 bp duplication) showed an association with verbal memory skills, and the SLC6A3 40 bp VNTR polymorphism could be linked to differences in inhibition. Interestingly, the presence of the risk alleles in DRD4 and SLC6A3 was related to better cognitive performance. Our findings contribute to an improved understanding of the functional implications of risk genes for ADHD. © 2007 Wiley‐Liss, Inc.