bluuebunny/crossref_metadata_2025 huggingface dataset:
Neural Differentiation of Human ES Cells
Authors: A. Cohen Malkiel , Itsykson Pavey , E. Reubinoff Benjamin
Published: October 2007

Human embryonic stem cells (hESCs) may be converted into highly enriched cultures of neural precursors under defined culture conditions. The neural precursors can proliferate in culture for prolonged periods of time, and can differentiate in vitro into mature neurons, astrocytes, and oligodendrocytes. The neurons are functional and have normal electrophysiological properties. After transplantation to the developing rodent brain, the neural precursors migrate extensively into the host brain parenchyma, respond to host brain signals, and differentiate in a region‐specific manner to progeny of the three neural lineages. The establishment of neuroectodermal precursors from hESCs allows the study of human neurogenesis in vitro and is an aid in drug discovery. In addition, the neural precursors may potentially serve as a platform for the development of specific functional neural cells for transplantation and gene therapy of neurological disorders. In this unit, we introduce methods for the derivation, propagation and characterization of hESC‐derived neural precursors. Curr. Protoc. Cell Biol. 36:23.7.1‐23.7.20. © 2007 by John Wiley & Sons, Inc.
Cotrimerizations of Acetylenic Compounds
Authors: Agenet Nicolas , Buisine Olivier , Slowinski Franck , Gandon Vincent , Aubert Corinne , Malacria Max
Published: October 2007

The cyclotrimerization of acetylenic compounds is a useful method for the construction of three new bonds in a one‐step process. Although symmetry‐allowed, there is a paucity of examples of purely thermal [2+2+2] cycloadditions. The first example reported was in 1866, which was the cyclization of acetylene to benzene. High temperatures are required for this reaction and a mixture of products is formed. In 1948, Reppe discovered the first transition‐metal catalyzed version of this reaction in which nickel was used and substituted benzenes were formed. Since then catalysts based on transition metals, lanthanides, actinide, and aluminum have been developed for the cycloaddition of substituted alkynes to benzene derivatives. Many compounds can take part in the cyclization reactions to give four‐, five‐,six, or eight membered rings. Many of these reactions have found many applications in organic synthesis

This chapter is devoted to early to late transition metal‐mediated cotrimerization of acetylenic compounds directed towards organic synthesis. It addresses the scope and generality of the reaction, as well as the current state of the art, with regard to region‐and stereoselectivities. In the context of selectivity, a mechanistic overview is provided. Inter‐and intramolecular versions of the cyclizations are presented with an emphasis on applications in synthesis. The literature up to mid‐2004 is covered.
Glycosylation on Polymer Supports
Authors: Bufali Simone , Seeberger Peter H.
Published: October 2007

Oligosaccharide synthesis has gained major attention in the last two decades particularly in the total synthesis of biologically interesting molecules. Carbohydrates contain many stereocenters and are often branched oligomers. The preparation of these complex methods is time consuming and mostly carried out by specialized laboratories. The synthesis of oligosaccharides is challenging because every glycosylation creates a new stereogenic center. Each carbohydrate unit has up to four sites for chain elongation, which exhibit similar reactivity. The strategic choice of protection for the hydroxyl and amino groups is essential

The use of polymeric support can simplify the synthesis. Glycosylation efficiency can be increased using one coupling partner (either the glycoside nucleophile or glycoslyating agent) or other reagent in excess. Use of polymeric supports results in shortened process times since intermediate purification steps are not required. This chapter deals with the choice of carbohydrate monomers or dimers including the protecting groups and an anomeric leaving group, the choice of polymer support, and the selection of a proper linker resistant to all relevant reaction conditions. The choice of carbohydrate building blocks requires an appropriate protecting group strategy. It is important to consider whether the carbohydrate is connected to the support via the anomeric position or another hydroxyl group.
Sickle cell disease and pulmonary hypertension in Africa: A global perspective and review of epidemiology, pathophysiology, and management
Authors: Aliyu Zakari Y. , Kato Gregory J. , Taylor James , Babadoko Aliyu , Mamman Aisha I. , Gordeuk Victor R. , Gladwin Mark T.
Published: October 2007

Secondary pulmonary hypertension (PAH) has been shown to have a prevalence of 30% in patients with sickle cell disease (SCD) with mortality rates of 40% at 40 months after diagnosis in the United States. The burden of SCD is highest in sub‐Saharan Africa, especially in Nigeria (West Africa), where approximately 6 million people are afflicted. The true global incidence, prevalence, and burden of SCD and its associated end organ complications however remain unknown. Chronic hemolysis represents a prominent mechanistic pathway in the pathogenesis of SCD‐associated pulmonary hypertension via a nitric oxide (NO) scavenging and abrogation of NO salutatory effects on vascular function, including smooth muscle relaxation, downregulation of endothelial adhesion molecules and inhibition of platelet activation. Many known infectious risk factors for PAH are also hyperendemic in Africa, including Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome (HIV/AIDS), chronic hepatitis B and C, and possibly malaria. Interactions between these infectious complications and SCD‐related hemolysis could yield an even higher prevalence of pulmonary hypertension and compound the existing global health systems challenges in managing SCD. Indeed, our preliminary analysis of African immigrants currently in the United States suggests that pulmonary hypertension represents a significant complication of SCD in the African subcontinent. There is clearly a need to include Africa and other parts of the world with high SCD prevalence in future comprehensive studies on the epidemiology and treatment of end organ complications of an aging SCD population world‐wide. Am. J. Hematol., 2008. Published 2007 Wiley‐Liss, Inc.
Chromosome 5q subtelomeric deletion syndrome
Authors: Rauch Anita , Dörr Helmuth‐Günther
Published: October 2007

The pure 3.5 Mb subtelomeric deletion syndrome is very rare but causes a recognizable phenotype characterized by prenatal lymphedema with increased nuchal translucency, pronounced muscular hypotonia in infancy, borderline intelligence, postnatal short stature with delayed bone age due to growth hormone deficiency, and multiple minor anomalies including mildly bell‐shaped chest, minor congenital heart defects, and a distinct facial gestalt. Terminal deletions including the adjacent ∼2 Mb NSD1‐locus show a compound phenotype with overlap to Sotos syndrome. Larger terminal deletions including also chromosomal bands 5q35.1 and 5q35.2 cause a more severe phenotype with normal body length, significant congenital heart defect, microcephaly, profound developmental retardation or early death due to respiratory failure. Heart defects in the latter are explained by haploinsufficiency of the NKX2.5 gene at 5q35.1. The deletion breakpoint of the 3.5 Mb subtelomeric microdeletion maps to a low copy repeat which is identical to the distal copy of two highly similar regions flanking the recurrent interstitial NSD1 microdeletion. As meiotic mispairing between these low copy repeats seem to be much more likely than a terminal aberration, these neighborhood may prevent occurrence of the subtelomeric deletion syndrome, which could explain the rareness of the latter. © 2007 Wiley‐Liss, Inc.
DNA‐binding, antibacterial and spectral investigations of drug–Fe(II) complexes
Authors: Pansuriya Pramod B. , Patel Mohan N.
Published: October 2007

The antibiotic agent ciprofloxacin is well known for its drug design and coordinating ability towards metal ions. Iron(II) complexes of ciprofloxacin with various neutral bidentate ligands have been prepared. The structure of complexes has been investigated using spectral, physicochemical and elemental analyses. Antibacterial activity has been carried out using agar plate technique against Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Salmonella typhi, Escherichia coli and Serratia marcescens. The results show a significant increase in antibacterial activity compared with parental ligands, metal salt and standard drugs (ofloxacin, levofloxacin). The DNA binding and cleavage efficacy were determined using absorption titration and gel electrophoresis techniques, respectively. The DNA binding and cleavage efficacy were increased in complexes compared with parental ligands and metal salt. Copyright © 2007 John Wiley & Sons, Ltd.
Tragwerkssimulation von Verbundkonstruktionen aus Stahlbeton – Teil 1: Konzept und dreidimensionale Modellbildung
Authors: Lindig Volker
Published: October 2007

Bestimmte Konstruktionen und außergewöhnliche Beanspruchungen machen es mitunter auch bei der praktischen Tragwerksplanung erforderlich, realitätsnahe Simulationen durchzuführen, um z. B. die Entscheidungsfindung rechnerisch abzusichern sowie Detaillösungen zu beurteilen. Versuche sind auf einfache Modelltragwerke beschränkt. Eine Bewertung realer Tragwerke kann nur auf der Basis numerischer Simulationsverfahren erfolgen. Voraussetzung für solche dreidimensionalen Tragwerksanalysen unter dem Aspekt der Gebrauchs‐ und Grenztragfähigkeit sind geeignete Modelle zur Berücksichtigung der vielfältigen physikalisch nichtlinearen Einflüsse. Universelle FE‐Programme bieten hierfür die grundsätzliche Möglichkeit, eigene Materialmodelle in Abhängigkeit von der Zielstellung einzusetzen. Bei Verbundtragwerken ergibt sich zusätzlich das Problem der nachgiebigen Fuge, deren Einfluss auf das Gesamttragverhalten bedeutsam ist. Der Beitrag gliedert sich in 2 Teile: Teil 1 zeigt einen vorteilhaften Weg der Modellbildung auf. In Teil 2 werden spezifische Ansätze für die dreidimensionale Modellierung der Verbundfuge abgeleitet. Zudem folgt für eine generierte Verbundrahmenkonstruktion die Beschreibung von Detailuntersuchungen im Eckbereich. Es werden Empfehlungen für die Konstruktion gegeben.
Nachweis der Gebrauchstauglichkeit von Bauteilen aus Stahlbeton nach DIN 1045 und nach EC 2
Authors: Friedrich Richard
Published: October 2007

Der Beitrag behandelt die häufig vorkommenden biegebeanspruchten Bauteile mit rechteckförmigem Querschnitt aus normalfestem Normalbeton C 20 bis C 50 mit einseitiger Bewehrung aus Betonstahl BSt 500. Bei der Berechnung der Durchbiegung w wird das Betonkriechen und ‐schwinden berücksichtigt, bei der Berechnung der Rißbreite wk und der Spannungen σc und σs das Kriechen allein.
Maternal mental health and faltering growth in infants
Authors: Dunne Laura , Sneddon Helga , Iwaniec Dorota , Stewart Moira C.
Published: October 2007

This study reports on the first phase of a large‐scale, longitudinal, multidisciplinary community study examining the growth, learning and development of young children with a particular focus on failure to thrive without organic cause. However, the group identified in this study may be better described as weight faltering. This paper examines the psychological data collected using the Parenting Stress Index, Rosenberg Self‐Esteem and the General Health Questionnaire in relation to child growth. There were no significant differences between the mothers of the weight faltering and control children in terms of parenting stress, maternal depression, maternal perceptions of their parenting competence or maternal self‐esteem. Maternal sensitivity to comments about child size, regardless of direction, had a negative impact on mood. Copyright © 2007 John Wiley & Sons, Ltd.
Bayesian latent variable regression via Gibbs sampling: methodology and practical aspects
Authors: Chen Hongshu , Bakshi Bhavik R. , Goel Prem K.
Published: October 2007

Bayesian latent variable regression (BLVR) aims to utilize all available information for empirical modeling via a Bayesian framework. Such information includes prior knowledge about the underlying variables, model parameters and measurement error distributions. This paper improves upon the existing optimization‐based BLVR (BLVR‐OPT) method [1] by developing a sampling‐based Bayesian latent variable regression (BLVR‐S) method that relies on Gibbs sampling. Use of the sampling‐based framework not only provides point estimates, but its ability to generate samples that represent the posterior distribution of the unknown variables, also readily provides error bounds. Features and advantages of this method are demonstrated via examples based on simulated data and real Near‐Infrared (NIR) spectroscopy data. Practical aspects of Bayesian modeling such as determining when the extra computation may be worth the effort are addressed by an empirical study of the effects of the amount of training data and signal to noise ratio (SNR). The benefits of BLVR seem to be most significant when the number of measurements is limited and when noise in output variables is relatively large. Copyright © 2007 John Wiley & Sons, Ltd.
Inclusion Complexes for Use in Room‐Temperature Gas‐Sensor Design
Authors: Mi Liwei , Hou Hongwei , Xu Jiaqiang , Xu Hong , Song Zhiyong , Tang Mingsheng , Fan Yaoting
Published: October 2007

The inclusion complex [{Co(bpy)(H2O)4}·(fcds)]n (1), which has been constructed using the guest molecule ferrocene‐1,1′‐disulfonate (fcds), the bridging ligand 4,4′‐bipyridine (bpy) and d7 Co2+, contains an infinite zigzag chain formed by the central CoII ion and the bridging bpy ligand. Guest fcds molecules lie between two adjacent zigzag chains. The highly conjugated structure of complex 1 means that it can be used as a metal‐organic semiconductor, and it also shows a high response to liquefied petroleum gas (LPG) and ethanol/petroleum ether (EP) at room temperature. The inclusion complexes [{Co(bpp)2(H2O)2}·(fcds)·4H2O]n [2; bpp = 1,3‐bis(4‐pyridyl)propane] and [{Zn(bpy)(H2O)4}·(fcds)]n (3), on the other hand, cannot be employed as room‐temperature gas sensors because they are insulators. The electrical resistivity of inclusion complex [{Ni(bpy)(H2O)4}·(fcds)]n (4) is 621 MΩ, whereas that of [{Co(bpy)(H2O)4}SO4·(4‐abaH)2·3H2O]n (5) (4‐abaH = 4‐aminobenzoic acid) is only 137 MΩ. This means that the semi‐conducting properties of such inclusion complexes depend on both the conjugated structure and the central metal ions. Furthermore, conjugated inclusion complexes with an odd number of electrons could be useful for the design of highly selective room‐temperature gas sensors.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Tetranuclear Nickel(II) Complexes Composed of Pairs of Dinuclear LNi2 Fragments Linked by Acetylenedicarboxylate, Terephthalate, and Isophthalate Dianions: Synthesis, Structures and Magnetic Properties
Authors: Klingele Julia , Klingele Marco H. , Baars Oliver , Lozan Vasile , Buchholz Axel , Leibeling Guido , Plass Winfried , Meyer Franc , Kersting Berthold
Published: October 2007

The tetranuclear nickel(II) complexes [(LNiII2)2(acetylenedicarboxylate)][BPh4]2 (2[BPh4]2), [(LNiII2)2(terephthalate)][BPh4]2 (3[BPh4]2), and [(LNiII2)2(isophthalate)][BPh4]2(4[BPh4]2), where L2– represents a macrocyclic hexaaza‐dithiophenolate ligand, have been synthesized and characterised by UV/Vis spectroscopy, IR spectroscopy, X‐ray crystallography, and magnetic susceptibility measurements. Each dicarboxylate dianion acts as a quadridentate bridging ligand linking two bioctahedral LNi2 units via μ1,3‐bridging carboxylate functions to generate discrete [(LNiII2)2(dicarboxylate)]2+ dications with a central LNi2(O2C–R–CO2)Ni2L core. The structures differ mainly in the distance between the center of the Ni···Ni axes of the isostructural LNi2 units (8.841(1) Å in 2[BPh4]2, 10.712(1) in 3[BPh4]2, and 9.561(1) in 4[BPh4]2) and the tilting angle between the two Ni2O2 planes (86.3° in 2[BPh4]2, 58.2° in 3[BPh4]2, 20.9° in 4[BPh4]2). Magnetic susceptibility measurements on the complexes over the range 2.0–295 K reveal the presence of weak ferromagnetic exchange interactions between the NiII ions within the dinuclear subunits with values for the magnetic exchange constant J1 of 23.1(5), 18.1(5), and 14.2(5) cm–1 for 2[BPh4]2, 3[BPh4]2, and 4[BPh4]2, respectively (H = –2JS1S2). The magnitude of the exchange interaction J2 across the dicarboxylate bridges is in all cases less than 0.1 cm–1, suggesting that no significant interdimer exchange coupling occurs in 2[BPh4]2–4[BPh4]2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Aggregation Phenomena of Long α‐ and α,ω‐Substituted Oligothiophenes – the Effect of Branched vs. Linear End‐Groups
Authors: Ellinger Stefan , Kreyes Andreas , Ziener Ulrich , Hoffmann‐Richter Carola , Landfester Katharina , Möller Martin
Published: October 2007

Five homologous series of α‐ and α,ω‐substituted oligothiophenes up to an undecamer with branched and linear alkyl chains, respectively, are presented. These series are compared with respect to self‐organisation in solution and in solid state. UV/Vis absorption data for the long disubstituted branched oligothiophenes indicate the formation of aggregates in solution, expressed by a bathochromic shift of the absorption maximum and the appearance of shoulders. These changes in the spectra are obtained by variation of the solvent quality and/or the temperature. Contrary, the linear disubstituted oligothiophenes exhibit the formation of H‐aggregates in solution indicated by a hypsochromic shift in the UV/Vis spectra. Results from fluorescence spectroscopy support the existence of aggregates. No aggregation phenomena were found for the monoalkylated branched oligothiophenes. In contrast, H‐aggregation is found for the monoalkylated linear oligomers. This unexpected influence of the branching of the alkyl end groups on the aggregation behaviour in solution is discussed with the aid of mixed substituted oligothiophenes. Further information on shape and size of the aggregates present in solution is found by AFM measurements revealing that the linear substituents rather provoke the formation of anisotropic structures whereas the branched alkyl chains lead to spherical nanoobjects. Investigations of the thermal behaviour in solid state show that some of the oligomers exhibit thermotropic liquid crystalline phases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
One‐Step Addition of Sulfonic Acids to Acetylene Derivatives: An Alternative and Stereoselective Approach to Vinyl Triflates and Fluorosulfonates
Authors: Vasilyev Aleksander V. , Walspurger Stéphane , Chassaing Stefan , Pale Patrick , Sommer Jean
Published: October 2007

Acetylenic acids and esters as well as acetylenic ketones were efficiently and stereoselectively converted in one step to the corresponding vinyl triflates or fluorosulfonates in triflic or fluorosulfonic acids. Depending on the reaction conditions the E or the Z isomer can be obtained very conveniently in high isolated yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Decadal changes in distribution and frequency of wood in a free meandering river, the Ain River, France
Authors: Lassettre Neil S. , Piégay Hervé , Dufour Simon , Rollet Anne‐Julia
Published: October 2007

This study examined the temporal dynamics and longitudinal distribution of wood over a multi‐decadal timescale at the river reach scale (36 km) and a meander bend scale (300–600 m) in the Ain River, a large gravel‐bed river flowing through a forested corridor, and adjusting to regulation and floodplain land‐use change.

At the 36 km scale, more wood was recruited by bank erosion in 1991–2000 than since the 1950s. The longitudinal distribution of accumulations was similar between 1989 and 1999, but in both years individual pieces occurred homogeneously throughout the reach, while jam distribution was localized, associated with large concave banks. A relationship between the mean number of pieces and the volume recruited by bank erosion (r2= 0·97) indicated a spatial relationship between areas of wood production and storage.

Wood mass stored and produced and channel sinuosity increased from 1993 to 2004 at three meander bends. Sinuosity was related to wood mass recruited by bank erosion during the previous decade (r2= 0·73) and both of these parameters were correlated to the mean mass of wood/plot (r2= 0·98 and 0·69 respectively), appearing to control wood storage and delivery at the bend scale. This suggests a local origin of wood stored in channel, not input from upstream trapped by preferential sites.

The increase in wood since 1950 is a response to floodplain afforestation, to a change from braided to meandering channel pattern in response to regulation, and to recent large floods. We observed temporal stability of supply and depositional sectors over a decade (on a reach scale). Meander bends were major storage sites, trapping wood with concave banks, also delivering wood. These results, and the link between sinuosity and wood frequency, establish geomorphology as a dominant wood storage and recruitment control in large gravel‐bed rivers. Copyright © 2007 John Wiley & Sons, Ltd.
Modelling volatility clustering in electricity price return series for forecasting value at risk
Authors: Karandikar R. G. , Deshpande N. R. , Khaparde S. A. , Kulkarni S. V.
Published: October 2007

Modelling of non‐stationary time series using regression methodology is challenging. The wavelet transforms can be used to model non‐stationary time series having volatility clustering. The traditional risk measure is variance and now a days Value at Risk (VaR) is widely used in finance. In competitive environment, the prices are volatile and price risk forecasting is necessary for the market participants. The forecasting period may be 1 week or higher depending upon the requirement. In this paper, a model is developed for volatility clustering in electricity price return series and its application for forecasting VaR is demonstrated. The first model is using GARCH (1, 1). The VaR of variance rate series, that is worst‐case volatility is calculated using variance method using wavelet transform. The model is used to forecast variance rate (volatility) for a sample case of 1‐week half‐hourly price return series. The second model developed is for forecasting VaR for price return series of 440 days. This model is developed using waveletsviamulti‐resolution analysis and uses regime‐switching technique. The historical data of daily average prices is obtained from 100% pool type New South Wales (NSW), a zonal market of National Electricity Market (NEM), Australia. Copyright © 2007 John Wiley & Sons, Ltd.
An upwind finite‐volume element scheme and its maximum‐principle‐preserving property for nonlinear convection–diffusion problem
Authors: Gao Fuzheng , Yuan Yirang , Yang Danping
Published: October 2007

For a class of nonlinear convection–diffusion equation in multiple space dimensions, a kind of upwind finite‐volume element (UFVE) scheme is put forward. Some techniques, such as calculus of variations, commutating operators and prior estimates, are adopted. It is proved that the UFVE scheme is unconditionally stable and satisfies maximum principle. Optimal‐order estimates in H1‐norm are derived to determine the error in the approximate solution. Numerical results are presented to observe the performance of the scheme. Copyright © 2007 John Wiley & Sons, Ltd.
Lack of correlation between synaptopodin expression and the ability to induce LTP in the rat dorsal and ventral hippocampus
Authors: Vlachos Andreas , Maggio Nicola , Segal Menahem
Published: October 2007

Synaptopodin (SP), an actin binding protein associated with the spine apparatus, has been proposed to affect the ability of neurons to undergo synaptic plasticity. In the present study, we compared the density of SP puncta in stratum radiatum of the dorsal hippocampus (DH) with that of the ventral hippocampus (VH), a region that expresses only small and short lived LTP. Surprisingly, the VH contains significantly higher density of SP puncta than the DH. Following exposure to an acute stress, LTP was enhanced in the VH and suppressed in the DH. While SP density did change following stress, no similar trends were seen in the two sectors of the hippocampus. Thus, our results indicate a lack of clear interrelation between the density of SP and the ability to express LTP in the hippocampus. © 2007 Wiley‐Liss, Inc.
Removal of dentin matrix proteoglycans by trypsin digestion and its effect on dentin bonding
Authors: Bedran‐Russo Ana Karina B. , Pereira Patricia N. R. , Duarte Wagner R. , Okuyama Katsushi , Yamauchi Mitsuo
Published: October 2007

The aim of this study was to investigate the effect of trypsin digestion on removal of chondroitin sulfate proteoglycans (CS‐PGs) in demineralized dentin, and subsequent dentin bonding. Bovine dentin fragments were demineralized, treated with or without trypsin, stained with cupromeronic blue, and observed under transmission electron microscopy. Demineralized sections with or without trypsin digestion were also subjected to immunohistochemical analysis with anti‐chondroitin‐4‐sulfate (C4S) monoclonal antibody, 2‐B‐6. The presence of galactosamine and glucosamine in the trypsin digest was confirmed by amino acid analysis. Bond strength testing was performed on trypsin treated and control specimens where samples were either kept moist or dried and re‐wet, then bonded. Bond strength significantly decreased after trypsin treatment (p < 0.05). TEM, immunohistochemical, and amino acid analyses demonstrated that trypsin digestion efficiently removed C4S‐PGs from demineralized dentin matrix. This study indicates that the detrimental effects observed on dentin bonding by trypsinization may be due in part to the removal/cleavage of the C4S‐PGs, and further underscore the importance of C4S‐PGs on dentin bonding. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Evaluation of the antimicrobial activity of ebselen: Role of the yeast plasma membrane H+‐ATPase
Authors: Chan Grace , Hardej Diane , Santoro Michelle , Lau‐Cam Cesar , Billack Blase
Published: October 2007

Ebselen (2‐phenyl‐1,2‐benzisoselenazol‐3(2H)‐one) is a selenium‐containing antioxidant demonstrating anti‐inflammatory and cytoprotective properties in mammalian cells and cytotoxicity in lower organisms. The mechanism underlying the antimicrobial activity of ebselen remains unclear. It has recently been proposed that, in lower organisms like yeast, the plasma membrane H+‐ATPase (Pma1p) could serve as a potential target for this synthetic organoselenium compound. Using yeast and bacteria, the present study found ebselen to inhibit microbial growth in a concentration‐ and time‐dependent manner, and yeast and Gram‐positive bacteria to be more sensitive to this action (IC50 ∼ 2–5 μM) than Gram‐negative bacteria (IC50 < 80 μM). Washout experiments and scanning electron microscopic analysis revealed ebselen to possess fungicidal activity. In addition, ebselen was found to inhibit medium acidification by PMA1‐proficient haploid yeast in a concentration‐dependent manner. Additional studies comparing PMA1 (+/−) and PMA1 (+/+) diploid yeast cells revealed the mutant to be more sensitive to treatment with ebselen than the wild type. Ebselen also inhibited the ATPase activity of Pma1p from S. cerevisae in a concentration‐dependent manner. The interaction of ebselen with the sulfhydryl‐containing compounds L‐cysteine and reduced glutathione resulted in the complete and partial prevention, respectively, of the inhibition of Pma1p ATPase activity by ebselen. Taken together, these results suggest that the fungicidal action of ebselen is due, at least in part, to interference with both the proton‐translocating function and the ATPase activity of the plasma membrane H+‐ATPase. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:252–264, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20189
Lead‐induced alterations of apoptosis and neurotrophic factor mRNA in the developing rat cortex, hippocampus, and cerebellum
Authors: Chao Shirley L. , Moss Jason M. , Harry G. Jean
Published: October 2007

Previous reports have recently shown the prototypic neurotoxicant, lead, to induce apoptosis in the brains of developing organisms. In the current study, timed‐pregnant rats were exposed to lead acetate (0.2% in the drinking water) 24 h following birth at postnatal day 1 (PND 1). Dams and pups were continuously exposed to lead through the drinking water of the dam until PND 20. Postnatal exposure in the pups resulted in altered mRNA levels of the following apoptotic and neurotrophic factors: caspase 2 and 3, bax, bcl‐x, brain‐derived neurotrophic factor (BDNF). Ribonuclease protection assays were conducted to measure the factors simultaneously at the following postnatal time points: 9, 12, 15, 20, 25, days. Our results suggest a brain region‐ and time‐specific response following lead acetate exposure. The region most vulnerable to alterations occurs in the hippocampus with alterations beginning at PND 12, in which caspase 3, bcl‐x, BDNF increase with lead exposure. Significant treatment effects were not observed for both the cortex and cerebellum. © 2007 Wiley Periodicals, Inc. J Biochem Mol Toxicol 21:265–272, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20191
Deregulation of cofactor of BRCA1 expression in breast cancer cells
Authors: Sun Jianlong , Watkins Gareth , Blair Ashley L. , Moskaluk Christopher , Ghosh Sagar , Jiang Wen G. , Li Rong
Published: October 2007

Cofactor of BRCA1 (COBRA1) is an integral component of the human negative elongation factor (NELF), a four‐subunit protein complex that inhibits transcription elongation. Previous in vivo work indicates that COBRA1 and the rest of the NELF complex repress estrogen‐dependent transcription and the growth of breast cancer cells. In light of the COBRA1 function in breast cancer‐related gene expression, we sought to examine regulation of COBRA1 expression in both established breast cancer cell lines and breast carcinoma tissues. We found that COBRA1 expression was inversely correlated with breast cancer progression, as tumor samples of patients who had distant metastasis and local recurrence expressed very low levels of COBRA1 mRNA when compared to those who were disease free for over 10 years (P = 0.0065 and 0.0081, respectively). Using both breast and prostate cancer cell lines, we also explored the possible mechanisms by which COBRA1 expression is regulated. Our results indicate that the protein abundance of COBRA1 and the other NELF subunits are mutually influenced in a tightly coordinated fashion. Small interfering RNA (siRNA) that targeted at one NELF subunit dampened the protein levels of all four subunits. Conversely, ectopic expression of COBRA1 in the knockdown cells partially rescues the co‐depletion of the NELF subunits. In addition, our study suggests that a post‐transcriptional, proteasome‐independent mechanism is involved in the interdependent regulation of the NELF abundance. Furthermore, a lack of COBRA1 expression in breast carcinoma may serve as a useful indicator for poor prognosis. J. Cell. Biochem. 103: 1798–1807, 2008. © 2007 Wiley‐Liss, Inc.
Biodegradation kinetics of the soluble slowly biodegradable substrate in polyamide carpet finishing wastewater
Authors: Yildiz Günay , Insel Güçlü , Cokgor Emine Ubay , Orhon Derin
Published: October 2007

BACKGROUND: Carpet manufacturing and finishing with purely synthetic fibers has received relatively little attention, compared to other textile processing types. This study evaluates the biodegradation kinetics of organic compounds generated from polyamide‐based carpet manufacturing.

RESULTS: Experiments were conducted on pre‐washing and dyeing/softening wastewater effluents. Model evaluation of oxygen uptake rate profiles with dual hydrolysis kinetics revealed that the soluble slowly hydrolysable chemical oxygen demand (COD) was the major fraction, constituting nearly 97% of the biodegradable COD and 78% of total COD content. Degradation of the slowly hydrolysable COD fraction was characterized with a rate coefficient of 0.72 day−1, a significant rate limiting step for substrate utilization. Model simulation of system performance indicated that an unusually long hydraulic retention time was required for an activated sludge system to reduce the effluent COD concentration.

CONCLUSION: Compared to domestic wastewater, two additional hydrolysable COD fractions with different degradation kinetics were characterized. The dyeing and softening step had the highest slowly biodegradable organic matter content, with the lowest degradation rate. Simulation results showed that soluble slowly hydrolysable COD degradation did not cause any problem in terms of effluent quality. With the system operated under reduced solids retention time, the effluent COD quality was significantly influenced by the slow hydrolysis rate of soluble hydrolysable matter. Copyright © 2007 Society of Chemical Industry
Improvement of the catalytic performance of lignin peroxidase in reversed micelles
Authors: Lan Jing , Zhang Yun , Huang Xirong , Hu Ming , Liu Weifeng , Li Yuezhong , Qu Yinbo , Gao Peiji
Published: October 2007

BACKGROUND: Anionic surfactant sodium bis (2‐ethylhexyl) sulfosuccinate (AOT) had an inhibiting effect on lignin peroxidase (LiP). To improve the catalytic activity of LiP in an AOT reversed micelle in isooctane, nonionic surfactant polyoxyethylene lauryl ether (Brij30) was incorporated into the interfacial membrane. H2O2 played dual roles in the LiP‐catalyzed oxidation of substrates. To obtain a sustainable high activity of LiP, a coupled enzymatic reaction, i.e. the glucose oxidase (GOD)‐catalyzed oxidation of glucose was used as an H2O2 source.

RESULTS: Owing to modification of the charge density of the interfacial membrane, the activity of LiP in an optimized AOT/Brij30 reversed micellar medium (χB (the molar percentage of Brij30) = 0.53, ω0 ([H2O]/([AOT] + [Brij30]) = 23, pH = 4.8) was 40 times that in a single AOT reversed micelle. Due to the controlled release of H2O2, the concentration of H2O2 in the mixed reversed micellar medium was maintained at a moderately high level throughout, which made the LiP‐catalyzed oxidation of substrates proceed at a higher conversion rate than counterparts in which H2O2 was supplied externally in one batch at the beginning of the reaction. Decolourization of two waterless‐soluble aromatic dyes (pyrogallol red and bromopyrogallol red) using LiP coupled with GOD in the medium also demonstrated that a higher decolourization percentage was obtained if H2O2 was supplied enzymatically.

CONCLUSION: The proposed measures (both physicochemical and biochemical) were very effective, giving significant improvement in the catalytic performance of LiP in a single AOT reversed micelle in isooctane, which helped to degrade or transform hydrophobic aromatic compounds with LiP in reversed micelles more efficiently. Copyright © 2007 Society of Chemical Industry
Adsorptive removal of anionic and non‐ionic surfactants from aqueous phase using Posidonia oceanica (L.) marine biomass
Authors: Ncibi Mohamed Chaker , Mahjoub Borhane , Seffen Mongi
Published: October 2007

BACKGROUND:

In this study, the capability of low‐cost, renewable and abundant marine biomass Posidonia oceanica (L.) for adsorptive removal of anionic and non‐ionic surfactants from aqueous solutions have been carried out in batch mode. Several experimental key parameters were investigated including exposure time, pH, temperature and initial surfactant concentration.

RESULTS:

It was found that the highest surfactant adsorption capacities reached at 30 °C were determined as 2.77 mg g−1 for anionic NaDBS and as 1.81 mg g−1 for non‐ionic TX‐100, both at pH 2. The biosorption process was revealed as a thermo‐dependent phenomenon. Equilibrium data were well described by the Langmuir isotherm model, suggesting therefore a homogeneous sorption surface with active sites of similar affinities. The thermodynamic constants of the adsorption process (i.e. ΔG°, ΔH° and ΔS°) were respectively evaluated as − 8.28 kJ mol−1, 48.07 kJ mol−1 and − 42.38 J mol−1 K−1 for NaDBS and − 9.67 kJ mol−1, 95.13 kJ mol−1 and − 174.09 J mol−1 K−1 for TX‐100.

CONCLUSION:

Based on this research, valorization of highly available Posidonia oceanica biomass, as biological adsorbent to remove anionic and non‐ionic surfactants, seems to be a promising technique, since the sorption systems studied were found to be favourable, endothermic and spontaneous. Copyright © 2007 Society of Chemical Industry
Synthesis, characterization and biodistribution of 99mTc(CO)3–ABP and comparison with 99mTc–ABP
Authors: Liu Jian , Wang Fenglong , Zhang Junbo , Yang Shuye , Guo Haixun , Wang Xuebin
Published: October 2007

The (l‐hydroxy‐4‐amino‐butylidene‐l,l‐bisphosphate) (ABP) is a compound that inhibits bone resorption, and a highly effective drug in the treatment of metastatic bone disease. The fac‐[99mTc(CO)3(H2O)3]+ precursor was reacted with ABP in saline (pH=3–4) at 45°C for 15 min to produce the 99mTc(CO)3–ABP complex. The radiochemical purity (RCP) of the product was over 90% as measured by thin layer chromatography and high‐performance liquid chromatography. No decomposition of the complex at room temperature (25°C) was observed over a period of 6 h. Its partition coefficient indicated that it was a weak hydrophilic complex. The biodistribution in normal mice of 99mTc(CO)3–ABP complex differed greatly from that of 99mTc–ABP, and the former had a lower bone uptake as compared with that of the latter. The experiment results showed that the incorporation of the [99mTc(CO)3]+ core into the ABP ligand may drastically change the characterization and biological features as compared with 99mTc–ABP. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of carbon‐14‐labelled pyronaridine tetraphosphate
Authors: Park Sang Hyun , Pradeep Kannampalli , Jang Seung Ho
Published: October 2007

Pyronaridine tetraphosphate is an antimalarial drug which is currently being widely investigated for use in the chemotherapy of malaria. We synthesized carbon‐14‐labelled pyronaridine tetraphosphate (14C‐PNDP, 5) by a classical method and also by a microwave irradiation technique for use in biodistribution studies and pharmacokinetic analysis. The application of microwave irradiation facilitated the use of high temperatures resulting in decreased reaction time and employed far less amount of the starting material when compared with the classical method. 14C‐PNDP (5) thus synthesized had a chemical purity of >99% as determined by high‐performance liquid chromatography (HPLC) and a radiochemical purity of >99% as determined by radio‐HPLC. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of a deuterium‐labelled standard of bufotenine (5‐HO‐DMT)
Authors: Wang Yu‐Yun , Chen Chinpiao
Published: October 2007

The Batcho–Leimgruber strategy was employed to synthesize 3‐(2‐dimethylamino‐[2H4]‐ethyl)‐1H‐indol‐5‐ol (bufotenine, 5‐HO‐DMT) (8) from commercial 3‐methyl‐4‐nitro‐phenol (1), benzyl bromide and N,N–dimethylformamide–dimethylacetal. Compound 4 was synthesized from compound 3 using the Batcho–Leimgruber strategy in the presence of Raney nickel and hydrazine hydrate. Compound 4 was treated with oxalyl chloride, dimethylamine and lithium aluminum [2H4]‐hydride to yield [2‐(5‐benzyloxy‐1H‐indol‐3‐yl)‐[2H4]‐ethyl]‐dimethyl‐amine (7). The benzyl ether in compound 7 was cleaved by hydrogenolysis to give bufotenine 8. Copyright © 2007 John Wiley & Sons, Ltd.
Self‐adjoint sensitivity analysis of lossy dielectric structures with electromagnetic time‐domain simulators
Authors: Song Yunpeng , Li Ying , Nikolova Natalia K. , Bakr Mohamed H.
Published: October 2007

We present an efficient self‐adjoint approach for the computation of response derivatives in lossy inhomogeneous structures with time‐domain electromagnetic solvers. Our approach yields the responses and their derivatives with only one system analysis regardless of the number of optimizable parameters. The only requirement is to access the field solution at the perturbation grid points. The computation is performed as an independent post‐process outside the solver. This makes our approach easy to implement as stand‐alone software, which aids microwave design based on commercial computer‐aided design packages. We show that our sensitivity analysis approach yields Jacobians of second‐order accuracy for lossy dielectric structures. The approach is verified through 1‐D, 2‐D and 3‐D examples using the time‐domain field solutions obtained with solvers based on the finite‐difference time‐domain (FDTD) and transmission line modeling (TLM) methods. Copyright © 2007 John Wiley & Sons, Ltd.
Establishment of Azotobacter on plant roots: chemotactic response, development and analysis of root exudates of cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.)
Authors: Kumar Rakesh , Bhatia Ranjana , Kukreja K. , Behl Rishi Kumar , Dudeja Surjit Singh , Narula Neeru
Published: October 2007

Biofertilizers contribute in N2 fixation, P solubilization, phytohormone production and thus enhance plant growth. Beneficial plant‐microbe interactions and the stability and effectiveness of biofertilizer depend upon the establishment of bacterial strains in the rhizosphere of the plant. This interaction depends upon many factors, one of them being plant exudates. Root exudates are composed of small organic molecules like carbonic acids, amino acids or sugars etc., which are released into the soil and bacteria can be attracted towards these exudates due to chemotaxis. The chemotactic behaviour of Azotobacter strains was studied using cotton (Desi HD 123 and American H 1098) and wheat (WH 711) seedlings and the root exudates of these two plants were chemically characterized. Analysis of the root exudates revealed the presence of sugars and simple polysaccharides (glucose), amino acids (glutamate, lysine) and organic acids (citric acid, succinic acid, maleic acid, malonic acid). Differences between cotton cultivars in root exudates were observed which influenced chemotactic response in Azotobacter. These results indicate colonization with rhizobacteria which implies that optimal symbionts, on the sides of both plant cultivar and bioinoculant bacteria can lead to better plant growth under cultivation conditions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Regulation of pyrimidine formation in Pseudomonas oryzihabitans
Authors: West Thomas P.
Published: October 2007

The regulation of pyrimidine formation in the opportunistic human pathogen Pseudomonas oryzihabitans was investigated at the level of enzyme synthesis and at the level of activity for the pyrimidine biosynthetic pathway enzyme aspartate transcarbamoylase. Although pyrimidine supplementation of succinate‐grown P. oryzihabitans cells produced little effect on the de novo pyrimidine biosynthetic pathway enzyme activities, pyrimidine limitation experiments undertaken using an orotidine 5′‐monophosphate decarboxylase mutant strain isolated from P. oryzihabitans ATCC 43272 indicated that repression of enzyme synthesis by pyrimidines was occurring. Following pyrimidine limitation of the succinate‐grown decarboxylase mutant strain cells, aspartate transcarbamoylase and dihydroorotase activities were found to increase by about 3‐fold while dihydroorotate dehydrogenase and orotate phosphoribosyltransferase activities were also observed to increase relative to their activities in the mutant strain cells grown on excess uracil. At the level of enzyme activity, aspartate transcarbamoylase in P. oryzihabitans was strongly inhibited by pyrophosphate, ADP, ATP and GTP in the presence of saturating substrate concentrations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Postglacial relative sea‐level observations from Ireland and their role in glacial rebound modelling
Authors: Brooks Anthony J. , Bradley Sarah L. , Edwards Robin J. , Milne Glenn A. , Horton Ben , Shennan Ian
Published: October 2007

The British Isles have been the focus of a number of recent modelling studies owing to the existence of a high‐quality sea‐level dataset for this region and the suitability of these data for constraining shallow earth viscosity structure, local to regional ice sheet histories and the magnitude/timing of global meltwater signals. Until recently, the paucity of both glaciological and relative sea‐level (RSL) data from Ireland has meant that the majority of these glacial isostatic adjustment (GIA) modelling studies of the British Isles region have tended to concentrate on reconstructing ice cover over Britain. However, the recent development of a sea‐level database for Ireland along with emergence of new glaciological data on the spatial extent, thickness and deglacial chronology of the Irish Ice Sheet means it is now possible to revisit this region of the British Isles. Here, we employ these new data to constrain the evolution of the Irish Ice Sheet. We find that in order to reconcile differences between model predictions and RSL evidence, a thick, spatially extensive ice sheet of ∼600–700 m over much of north and central Ireland is required at the LGM with very rapid deglaciation after 21 k cal. yr BP. Copyright © 2007 John Wiley & Sons, Ltd.
Red clover (Trifolium pratense L.) isoflavones: determination of concentrations by plant stage, flower colour, plant part and cultivar
Authors: Saviranta Niina MM , Anttonen Mikko J , von Wright Atte , Karjalainen Reijo O
Published: October 2007

BACKGROUND: Red clover (Trifolium pratense L.), a widely used fodder, has recently received considerable interest as a valuable source of isoflavones for many health‐related applications. The aim of this study was to analyse the concentrations of four isoflavones, daidzein, genistein, formononetin and biochanin A, in extracts of leaves, stems, roots and different coloured flowers from red clover by high‐performance liquid chromatography and to determine the antifungal activities of the extracts.

RESULTS: Among greenhouse‐grown samples the highest amounts of daidzein and genistein were found in petioles (0.11–0.28 and 0.30–0.54 mg g−1 respectively), while leaves were rich in formononetin and biochanin A (5.57–9.05 and 10.94–14.59 mg g−1 respectively). High formononetin concentrations were found in roots, but very little biochanin A. Among field‐grown samples the highest concentrations of daidzein and genistein were detected in stems collected in August (0.24 and 0.55 mg g−1 respectively), while the highest amounts of formononetin and biochanin A were found in young leaves collected in June (7.47 and 9.69 mg g−1 respectively). Most of the extracts inhibited the growth of Drechslera teres, while the root extract showed the strongest effect against Microdochium nivale.

CONCLUSION: High levels of bioactive compounds found not only in inflorescences but also in roots, leaves and stems suggest that red clover may be an inexpensive and valuable resource for many applications. Copyright © 2007 Society of Chemical Industry
Phosphorus‐Containing Epoxy Curing Agents via Imine Linkage
Authors: Lin Ching Hsuan , Hwang Ting Yu , Taso Ya Ru , Lin Tsung Li
Published: October 2007

Two new phenol‐type curing agents, (3) and (4), were synthesized by the condensation of 4 (or 2)‐hydroxybenzaldehyde and 4‐aminophenol, followed by the addition of DOPO to the resulting imine linkage. Two reaction mechanisms, conjugate‐addition and carbocation mechanisms, were proposed. The fact that the ratio of the configuration of the two diastereomers depends on the reaction solvent indicates that the carbocation mechanism is the more reasonable one. (3) and (4) served as curing agents for epoxy resins, and the resulting epoxy thermosets exhibited good flame retardancy, and moderate Tg and thermal stability. The nitrogen‐phosphorus synergistic effect explains the high flame retardancy.

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