bluuebunny/crossref_metadata_2025 huggingface dataset:
Intermolecular Double Prins‐Type Cyclization: A Facile and Efficient Synthesis of 1,6‐Dioxecanes
Authors: Ullapu Punna Reddy , Min Sun‐Joon , Chavre Satish N. , Choo Hyunah , Lee Jae Kyun , Pae Ae Nim , Kim Youseung , Chang Moon Ho , Cho Yong Seo
Published: February 2009

Verdoppelter Einsatz: Die Titelreaktion überführt eine Reihe aromatischer Aldehyde in 26–85 % Ausbeute mithilfe von Allenylmethyl‐/Allylsilanen in 1,6‐Dioxecan‐Derivate (siehe Schema; Ar=Aryl, Tf=Triflat, THF=Tetrahydrofuran, TMS=Trimethylsilyl). Die Bisdien‐Produkte wurden durch Diels‐Alder‐Reaktionen in Tricyclen umgewandelt.

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The Role of Free N‐Heterocyclic Carbene (NHC) in the Catalytic Dehydrogenation of Ammonia–Borane in the Nickel NHC System
Authors: Zimmerman Paul M. , Paul Ankan , Zhang Zhiyong , Musgrave Charles B.
Published: February 2009

Enders' N‐heterocyclic carbene (NHC) dehydrogenates ammonia–borane with a relatively low barrier, producing NH2BH2 and NHC–(H)2. The nickel NHC catalyst present in the reaction media can activate the NHC–(H)2 produced to regenerate the free NHC and release H2. The release of free NHC enables further dehydrogenation of ammonia–borane.

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Photocontrolled Translational Motion of a Microscale Solid Object on Azobenzene‐Doped Liquid‐Crystalline Films
Authors: Kausar Abu , Nagano Hiroto , Ogata Tomonari , Nonaka Takamasa , Kurihara Seiji
Published: February 2009

On the move: Irradiation of azobenzene‐doped liquid crystalline films with UV/Vis light results in the photocontrolled translational motion of microscale solid object on the surface, which occurs throughcis–transisomerization of the azobenzene unit. Irradiation with an Ar+laser (488 nm) resulted in precise control of the translational motion so that the particle always moved away from the irradiation position (see picture).

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Evaluation of the potential use of ultrasound during the industrial manufacturing of high impact polystyrene
Authors: Bouquet Gilbert , Veraart Rudi , Peltier Jean
Published: February 2009

During the production of high impact polystyrene the rubber particle formation process is very important to control the final physical property balance. Besides the rubber viscosity, the presence of a copolymer to reduce the interfacial tension between the rubber and polystyrene phase is central. Such a copolymer can be added or can be made during the polymerization. In this study, it was attempted to create a block rubber in situ using ultrasound. Polybutadiene dissolved in styrene has been sonicated to create macroradicals. It was anticipated that these macroradicals would initiate the polymerization of styrene thus generating a poly(butadiene‐block‐styrene) acting as emulsifier during the production of high impact polystyrene. No evidence was found for the formation of a block copolymer but the higher reactivity and the resulting rubber particles indicate that besides rubber molecular weight reduction extra functionality was introduced on the rubber. No attempts were made to define the nature of the functionality. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Discrimination of the roles of crosslinking density and morphology in the swelling behavior of crosslinked polymers: Poly(N‐vinylimidazole) hydrogels
Authors: Pacios Isabel E. , Piérola Inés F.
Published: February 2009

The degree of swelling (S) of crosslinked polymers depends on several variables whose individual contributions are difficult to be distinguished. The aim of this work is to determine the contributions of the morphology to S, discriminating them from the effect of the crosslinking density. Under usual conditions of synthesis, these two characteristics vary simultaneously but here, several samples of chemically crosslinked poly(N‐vinylimidazole) having the same permanent crosslinking density (determined by DSC) and different porous morphologies (determined by SEM) were prepared. It was thus found that the variation of S with porosity, keeping constant the rest of variables, is strongly solvent dependent. Swelling in methanol is almost constant whereas for ethanol, deionized water, and aqueous HCl solutions, S depends on morphological features in a different way for each medium. It was concluded that S increases with inherent porosity and solvent effects arise from the counterbalance of such increment with the dependence of the polymer‐solvent interaction parameter on the polymer volume fraction. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Diffusivities of dichloromethane in poly(lactide‐co‐glycolide)
Authors: Foss Willard R. , Anderl Jeffrey N. , Clausi Amber L. , Burke Paul A.
Published: February 2009

Diffusion of dichloromethane in poly(lactide‐co‐glycolide) (PLGA), the rate‐limiting step in the later stages of drying of microparticles formed in common encapsulation processes, was studied by the step‐change sorption technique in a dynamic vapor sorption apparatus. Methods were developed to create films of polymer with the appropriate thicknesses for accurate diffusion determination over a wide range of solvent composition. Mutual diffusivities were measured at 5, 25, and 35°C from 10 to 70 wt % solvent. Values range from 2 × 10−10 m2/s at high solvent compositions to as low as 1 × 10−13 m2/s at solvent compositions just above the glass transition of the mixture. Equilibrium sorption isotherms were measured in the same apparatus and agreed favorably with Flory‐Huggins theory using a value of χ = 0.31. The glass transition temperatures of the system were measured over the range of 0–11 wt % solvent content by modulated differential scanning calorimetry. The composition dependence was fit to the Fox equation, which estimated values of the pure polymer and the solvent Tg to be 39.3 and −131°C, respectively. These values, along with the diffusivity data, were used to deduce the free‐volume parameters specific to PLGA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of isomery in drug release from poly(butyl monoitaconate‐co‐acrylamide) hydrogels
Authors: Katime Issa , Canjura O. , Cesteros L. C. , Mendizábal E. , Mendizábal Adriana P.
Published: February 2009

In this work, we report the synthesis and characterization of poly(butyl monoitaconate‐co‐acrylamide) hydrogels to be used as drug release agents. Four isomers of butanol were used to synthesize the hydrogels. The influence of butyl monoitaconate isomery on swelling behavior, Young's and compression moduli, cross‐linking density and molar mass between cross‐links are reported. It was found that by increasing butyl ramification, equilibrium degree of swelling, and the time for reaching swelling equilibrium decreases. Cross‐linking density, Young's and compression moduli increases as butyl ramification increases. The release of theophylline and aminophylline drugs used in therapy for respiratory diseases were studied and it was found that theophylline was released faster than aminophylline © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Evaluation of molecular orientation in injection molded parts with microscale features by Raman spectroscopy
Authors: Murakami Osamu , Yamada Kazushi , Kotaki Masaya , Hamada Hiroyuki
Published: February 2009

Molecular orientation of polycarbonate (PC) in injection‐molded parts with microscale features was characterized by means of polarized Raman spectroscopy, and the relationship between microstructure and replication was discussed. The microscale feature size of continuous v‐groove was 20 μm in depth and 50 μm in width. PC injection‐molded parts were molded with various molding conditions. The molecular orientation distribution along flow direction on the cross‐section of molding parts were evaluated by the intensity ratio of the bands at 635 to 703 cm−1 (I635/I703) in the Raman spectra. Molecular orientation along the flow direction inside the v‐groove was higher than that of the core and the opposite surface region. In particular, the highest molecular orientation was at the surface of the v‐groove. Among the injection molding conditions, the mold temperature showed significant effect on the molecular orientation and replication. Higher mold temperature caused high replication and low molecular orientation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The relative influence of advice from human experts and statistical methods on forecast adjustments
Authors: Önkal Dilek , Goodwin Paul , Thomson Mary , Gönül Sinan , Pollock Andrew
Published: February 2009

Decision makers and forecasters often receive advice from different sources including human experts and statistical methods. This research examines, in the context of stock price forecasting, how the apparent source of the advice affects the attention that is paid to it when the mode of delivery of the advice is identical for both sources. In Study 1, two groups of participants were given the same advised point and interval forecasts. One group was told that these were the advice of a human expert and the other that they were generated by a statistical forecasting method. The participants were then asked to adjust forecasts they had previously made in light of this advice. While in both cases the advice led to improved point forecast accuracy and better calibration of the prediction intervals, the advice which apparently emanated from a statistical method was discounted much more severely. In Study 2, participants were provided with advice from two sources. When the participants were told that both sources were either human experts or both were statistical methods, the apparent statistical‐based advice had the same influence on the adjusted estimates as the advice that appeared to come from a human expert. However when the apparent sources of advice were different, much greater attention was paid to the advice that apparently came from a human expert. Theories of advice utilization are used to identify why the advice of a human expert is likely to be preferred to advice from a statistical method. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of 100 mT homogeneous static magnetic field on [Ca2+]c response to ATP in HL‐60 cells following GSH depletion
Authors: Belton Michelle , Prato Frank S. , Rozanski Camilla , Carson Jeffrey J.L.
Published: February 2009

Calcium is an important molecule in a number of biological systems. Often these systems are signal transduction cascades involving molecules such as ATP. ATP activates second messengers which can interact with ion channels on the endoplasmic/sarcoplasmic reticulum resulting in the emptying of the intracellular calcium stores and an increase in cytosolic free calcium concentration ([Ca2+]c). Changes in [Ca2+]c can be influenced by external factors such as a static magnetic field (SMF). One hypothesis suggests that a SMF affects the cells through the radical pair mechanism. By reducing the number of antioxidant molecules like glutathione (GSH), the proportion of free radicals in the cells is increased and may lead to a greater probability of a biological response to a SMF. The purpose of this study was to determine if the [Ca2+]c response to ATP was affected by depletion of GSH by diethylmaleate (DEM) and the absence or presence of a 100 mT homogeneous SMF. Undifferentiated HL‐60 cells were loaded with fura‐2 AM. [Ca2+]c was measured in real time using a ratiometric fluorescence spectroscopy system. Various (DEM) ranging from 1 to 15 mM were added to deplete GSH. Cells were either exposed to sham or magnetic field (100 mT) for 13 min (780 s) and challenged with 1 µM ATP. The data show that [Ca2+]c was elevated following treatment with DEM with greater [Ca2+]c at higher [DEM]. The [Ca2+]c response to ATP was decreased as the DEM concentration increased. However, there was no effect of a 100 mT SMF on the average [Ca2+]c peak following ATP activation or the full width at half maximum (FWHM) of the [Ca2+]c response and recovery after ATP activation. Bioelectromagnetics 30:322–329, 2009 © 2009 Wiley‐Liss, Inc.
Shadows of complexity: what biological networks reveal about epistasis and pleiotropy
Authors: Tyler Anna L. , Asselbergs Folkert W. , Williams Scott M. , Moore Jason H.
Published: February 2009

Pleiotropy, in which one mutation causes multiple phenotypes, has traditionally been seen as a deviation from the conventional observation in which one gene affects one phenotype. Epistasis, or gene–gene interaction, has also been treated as an exception to the Mendelian one gene–one phenotype paradigm. This simplified perspective belies the pervasive complexity of biology and hinders progress toward a deeper understanding of biological systems. We assert that epistasis and pleiotropy are not isolated occurrences, but ubiquitous and inherent properties of biomolecular networks. These phenomena should not be treated as exceptions, but rather as fundamental components of genetic analyses. A systems level understanding of epistasis and pleiotropy is, therefore, critical to furthering our understanding of human genetics and its contribution to common human disease. Finally, graph theory offers an intuitive and powerful set of tools with which to study the network bases of these important genetic phenomena.
The ‘kinetochore maintenance loop’—The mark of regulation?
Authors: Brown William R. A. , Xu Zheng‐yao
Published: February 2009

Kinetochores can form and be maintained on DNA sequences that are normally non‐centromeric. The existence of these so‐called neo‐centromeres has posed the problem as to the nature of the epigenetic mechanisms that maintain the centromere. Here we highlight results that indicate that the amount of CENP‐A at human centromeres is tightly regulated. It is also known that kinetochore assembly requires sister chromatid cohesion at mitosis. We therefore suggest that separation or stretching between the sister chromatids at metaphase reciprocally determines the amount of centromere assembly in the subsequent interphase. This reciprocal relationship forms the basis of a negative feedback loop that could precisely control the amount of CENP‐A and faithfully maintain the presence of a kinetochore over many cell divisions. We describe how the feedback loop would work, propose how it could be tested experimentally and suggest possible components of its mechanism.
Dinoflagellate mitochondrial genomes: stretching the rules of molecular biology
Authors: Waller Ross F. , Jackson Christopher J.
Published: February 2009

Mitochondrial genomes represent relict bacterial genomes derived from a progenitor α‐proteobacterium that gave rise to all mitochondria through an ancient endosymbiosis. Evolution has massively reduced these genomes, yet despite relative simplicity their organization and expression has developed considerable novelty throughout eukaryotic evolution. Few organisms have reengineered their mitochondrial genomes as thoroughly as the protist lineage of dinoflagellates. Recent work reveals dinoflagellate mitochondrial genomes as likely the most gene‐impoverished of any free‐living eukaryote, encoding only two to three proteins. The organization and expression of these genomes, however, is far from the simplicity their gene content would suggest. Gene duplication, fragmentation, and scrambling have resulted in an inflated and complex genome organization. Extensive RNA editing then recodes gene transcripts, and trans‐splicing is required to assemble full‐length transcripts for at least one fragmented gene. Even after these processes, messenger RNAs (mRNAs) lack canonical start codons and most transcripts have abandoned stop codons altogether.
Using embryonic stem cells to form a biological pacemaker via tissue engineering technology
Authors: Ou Dong‐Bo , Lang Hong‐Juan , Chen Rui , Liu Xiong‐Tao , Zheng Qiang‐Sun
Published: February 2009

Biological pacemakers can be achieved by various gene‐based and cell‐based approaches. Embryonic stem cells (ESCs)‐derived pacemaker cells might be the most promising way to form biological pacemakers, but there are challenges as to how to control the differentiation of ESCs and to overcome the neoplasia, proarrhythmia, or immunogenicity resulting from the use of ESCs. As a potential approach to solve these difficult problems, tissue‐engineering techniques may provide a precise control on the different cell components of multicellular aggregates and the forming of a construct with‐defined architectures and functional properties. The combined interactions between ESC‐derived pacemaker cells, supporting cells, and matrices may completely reproduce pacemaker properties and result in a steady functional unit to induce rhythmic electrical and contractile activities. As ESCs have a high capability for self‐renewal, proliferation, and potential differentiation, we hypothesize that ESCs can be used as a source of pacemaker cells for tissue‐engineering applications and the ambitious goal of biological cardiac pacemakers may ultimately be achieved with ESCs via tissue‐engineering technology.
Development and characterization of a tissue engineered pancreatic substitute based on recombinant intestinal endocrine L‐cells
Authors: Bara Heather , Sambanis Athanassios
Published: February 2009

A tissue engineered pancreatic substitute (TEPS) consisting of insulin‐producing cells appropriately designed and encapsulated to support cellular function and prevent interaction with the host may provide physiological blood glucose regulation for the treatment of insulin dependent diabetes (IDD). The performance of agarose‐based constructs which contained either a single cell suspension of GLUTag‐INS cells, a suspension of pre‐aggregated GLUTag‐INS spheroids, or GLUTag‐INS cells on small intestinal submucosa (SIS), was evaluated in vitro for total cell number, weekly glucose consumption and insulin secretion rates (GCR and ISR), and induced insulin secretion function. The three types of TEPS studied displayed similar number of cells, GCR, and ISR throughout 4 weeks of culture. However, the TEPS, which incorporated SIS as a substrate for the GLUTag‐INS cells, was the only type of TEPS tested which was able to retain the induced insulin secretion function of non‐encapsulated GLUTag‐INS cells. Though improvements in the expression level of GLUTag‐INS cells and/or the number of viable cells contained within the TEPS are needed for successful treatment of a murine model of IDD, this study has revealed a potential method for promoting proper cellular function of recombinant L‐cells upon incorporation into an implantable three‐dimensional TEPS. Biotechnol. Bioeng. 2009;103: 828–834. © 2009 Wiley Periodicals, Inc.
Scale‐up analysis for a CHO cell culture process in large‐scale bioreactors
Authors: Xing Zizhuo , Kenty Brian M. , Li Zheng Jian , Lee Steven S.
Published: February 2009

Bioprocess scale‐up is a fundamental component of process development in the biotechnology industry. When scaling up a mammalian cell culture process, it is important to consider factors such as mixing time, oxygen transfer, and carbon dioxide removal. In this study, cell‐free mixing studies were performed in production scale 5,000‐L bioreactors to evaluate scale‐up issues. Using the current bioreactor configuration, the 5,000‐L bioreactor had a lower oxygen transfer coefficient, longer mixing time, and lower carbon dioxide removal rate than that was observed in bench scale 5‐ and 20‐L bioreactors. The oxygen transfer threshold analysis indicates that the current 5,000‐L configuration can only support a maximum viable cell density of 7 × 106 cells mL−1. Moreover, experiments using a dual probe technique demonstrated that pH and dissolved oxygen gradients may exist in 5,000‐L bioreactors using the current configuration. Empirical equations were developed to predict mixing time, oxygen transfer coefficient, and carbon dioxide removal rate under different mixing‐related engineering parameters in the 5,000‐L bioreactors. These equations indicate that increasing bottom air sparging rate is more efficient than increasing power input in improving oxygen transfer and carbon dioxide removal. Furthermore, as the liquid volume increases in a production bioreactor operated in fed‐batch mode, bulk mixing becomes a challenge. The mixing studies suggest that the engineering parameters related to bulk mixing and carbon dioxide removal in the 5,000‐L bioreactors may need optimizing to mitigate the risk of different performance upon process scale‐up. Biotechnol. Bioeng. 2009;103: 733–746. © 2009 Wiley Periodicals, Inc.
Teaching mobile and wireless information systems development in engineering courses
Authors: Licea Guillermo , Aguilar Leocundo , Juárez J. Reyes , Martínez Luis G.
Published: February 2009

MADEE (Mobile Application Development and Execution Environment) is a platform that supports the development of small and middle size mobile and wireless information systems for handheld devices. MADEE allows a student to develop applications faster and easier than using conventional development tools. This study presents the results and experience obtained using MADEE to support the introduction of mobile and wireless information systems development concepts in the context of computer engineering courses. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 261–268, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20251
A high‐performance and well‐manageable distributed measurement laboratory with an object‐oriented approach
Authors: Lai Yuan‐Cheng , Lin Jian‐Wei
Published: February 2009

The distributed measurement laboratory (DML) can provide users with the capability of performing and practicing their experiments in a transparent manner on remote instruments located in different geographic areas and connected with a wide area network. In this article, we propose a high‐performance and well‐manageable DML, named HPWM, which is characterized by three main novel features: (1) using .NET Remoting to provide better network performance and having scalable and extendable architecture; (2) using Asynchronous JavaScript and XML (AJAX) to provide an efficient and lightweight Graphic User Interface (GUI) without browser plug‐ins; and (3) offering adequate management functionalities to well manage users and instruments and establishing their relationships. The software structure used for developing HPWM is also described. Finally, HPWM has been tested in the academic and industrial education and has shown its correctness and effectiveness. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 344–355, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20265
Glucose deprivation increases nuclear DNA repair protein Ku and resistance to radiation induced oxidative stress in human cancer cells
Authors: Li Jie , Ayene Roashan , Ward Kathleen M. , Dayanandam Eswarkumar , Ayene Iraimoudi S.
Published: February 2009

Recent studies have indicated that nutrient deprivation particularly glucose may play a major role in tumor cell tolerance to a generally oxidative stress environment in solid tumors. Here, we studied the impact of glucose deprivation on the response of human colon (HT29) and prostate (DU145) cancer cells to γ radiation. A significant decrease in intracellular glucose level was observed in glucose deprived cells as measured by bioreductive assay. The survival of HT29 and DU145 were increased by 30 and 100% respectively when these cells were exposed to γ radiation in the absence of glucose compared to that in the presence of glucose. In glucose depleted medium, glutathione (GSH), a free radical scavenger, content remained the same, and showed no correlation with the radiation resistance induced by glucose deprivation. Glucose regulated protein78 (GRP78), a stress response survival protein, was not significantly increased in cells deprived of glucose for 4 h compared to those cells in glucose. DNA repair protein Ku, which is known to play a major role in cellular resistance to radiation, was significantly increased in glucose deprived cancer cells that showed enhanced radiation resistance. These results have demonstrated, for the first time, that glucose deprivation mediated stress increased the expression of nuclear Ku and resistance to radiation induced oxidative stress in human cancer cells. The additional resistance caused by glucose deprivation in cancer cells has clinical significance since solid tumors are known to have low level of glucose due to diffusion limited blood supply and higher metabolic activity. Copyright © 2009 John Wiley & Sons, Ltd.
Successful embolization of a left ventricular pseudoaneurysm after perventricular ventricular septal defect device closure
Authors: Breinholt John P. , Rodefeld Mark D. , Hoyer Mark H.
Published: February 2009

Perventricular device closure has become an important management adjunct for ventricular septal defects deemed inoperable and difficult to address in the catheterization laboratory. Complications directly related to the procedure are rarely reported, and all have been manifest in the periprocedural period. We present the case of a 6‐week‐old boy who underwent perventricular closure of a muscular ventricular septal defect and had a left ventricle pseudoaneurysm identified 10 months later during catheterization to close residual septal defects. We describe the subsequent percutaneous coil embolization of the pseudoaneurysm and clinical follow‐up. © 2009 Wiley‐Liss, Inc.
Use of Selenium to Detect Mercury in Water and Cells: An Enhancement of the Sensitivity and Specificity of a Seleno Fluorescent Probe
Authors: Tang Bo , Ding Baiyu , Xu Kehua , Tong Lili
Published: February 2009

Seleno fluorescent probe: An organoselenium fluorescent probe (FSe‐1) for mercury was designed based on the irreversible deselenation mechanism. FSe‐1 exhibits an ultrahigh selectivity and sensitivity for Hg2+ detection only for reactive selenium atom sites, due the strong affinity between Se and Hg. Furthermore, the new probe has been successfully used for imaging mercury ions in RAW 264.7 cells (a mouse macrophage cell line; see figure).

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Inspired by the antitoxic function of selenium towards heavy‐metal ions, we designed an organoselenium fluorescent probe (FSe‐1) for mercury. The reaction of FSe‐1 and Hg2+ is an irreversible deselenation mechanism based on the selenophilic character of mercury. FSe‐1 exhibits an ultrahigh selectivity and sensitivity for Hg2+ detection only for reactive selenium atom sites due to the strong affinity between Se and Hg. The experimental results proved that FSe‐1 was selective for Hg2+ ions over other relevant metal ions and bioanalytes, and also showed an enhancement in sensitivity of up to 1.0 nM, which is lower than the current Environmental Protection Agency standard for drinking water. Furthermore, the new probe has been successfully applied to the imaging of mercury ions in RAW 264.7 cells (a mouse macrophage cell line) with high sensitivity and selectivity.
Palladium‐Catalyzed Intramolecular Hydroamination of Allenes Coupled to Aerobic Alcohol Oxidation
Authors: Qiu Shuifa , Wei Yunyang , Liu Guosheng
Published: February 2009

Taking the air! A PdII‐catalyzed intramolecular hydroamination of allenes coupled to alcohol oxidation has been developed. This reaction is performed by using a nitrogen‐based ligand under aerobic conditions, under which the molecular oxygen is used as the terminal oxidant for the reoxidation of Pd0 species to complete the catalytic cycle.

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Cyclometalated Platinum(II) Complexes as Highly Sensitive Luminescent Switch‐On Probes for Practical Application in Protein Staining and Cell Imaging
Authors: Wu Peng , Wong Ella Lai‐Ming , Ma Dik‐Lung , Tong Glenna So‐Ming , Ng Kwan‐Ming , Che Chi‐Ming
Published: February 2009

Protein‐staining platinum: The luminescent switch‐on characteristic of the platinum(II) complex can be utilized for staining a series of proteins in sodium dodecyl sulfate‐polyarcylamide gels, to give emissive gel images directly under UV light (see figure). The detection sensitivity for BSA protein is down to 6.0 ng, revealing potential practical applications of luminescent platinum(II) complexes in the luminescent signaling of biomolecules.

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Catalytic Asymmetric Intramolecular Hydroarylations of ω‐Aryloxy‐ and Arylamino‐Tethered α,β‐Unsaturated Aldehydes
Authors: Lu Hai‐Hua , Liu Hui , Wu Wei , Wang Xu‐Fan , Lu Liang‐Qiu , Xiao Wen‐Jing
Published: February 2009

Economical approach: The first organocatalytic asymmetric intramolecular hydroarylation of phenol‐ and aniline‐derived enals offers one of the most straightforward and atom‐economic approaches to enantioriched chromans and tetrahydroquinolines (up to 96 % ee; see scheme).

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ChemInform Abstract: A Bio‐Inspired Copper Catalyst System for Practical Catalytic Cyanation of Aryl Bromides.
Authors: Schareina Thomas , Zapf Alexander , Cotte Alain , Mueller Nikolaus , Beller Matthias
Published: February 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Immobilization of NHC‐Bearing Palladium Catalysts on Polyvinylpyridine: Applications in Suzuki—Miyaura and Hartwig—Buchwald Reactions under Batch and Continuous‐Flow Conditions.
Authors: Mennecke Klaas , Kirschning Andreas
Published: February 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
High throughput multiplexed method for evaluation of enantioselective performance of chiral selectors by HPLC‐ESI‐MS and dynamic titration: Cinchona alkaloid carbamates discriminating N‐blocked amino acids
Authors: Fryčák Petr , Schug Kevin A.
Published: February 2009

Because of the generally different interaction of enantiomers with biological systems, there has been an ever increasing demand for artificial highly enantioselective systems that can facilitate separation processes involved in the research and development of enantiomerically pure drugs. Such systems may be discovered by large‐scale screening of compound libraries which warrants rapid and cost‐efficient screening methods. Here, we demonstrate enantioselectivity determination for systems of cinchona alkaloid carbamates and N‐blocked amino acids using HPLC‐MS and the recently developed dynamic titration technique (Fryčák P, Schug KA. Anal Chem 2008;80:1385‐1393). A mixture of nine N‐blocked amino acids (either D or L enantiomers) was separated on a reversed‐phase column with cinchona alkaloid carbamates added postcolumn. Dissociation constants of the observed noncovalent complexes were determined from the HPLC‐MS data. Enantioselectivity was then calculated from the dissociation constants, pointing out the best performing systems. For these systems, apparent dissociation constants were measured for the whole range of enantiomeric composition and were shown to obey a proposed theoretical model. Chirality, 2009. © 2009 Wiley‐Liss, Inc.
Chiral separation of catechin by capillary electrophoresis using mono‐, di‐, tri‐succinyl‐β‐cyclodextrin as chiral selectors
Authors: Kim Hyunmyung , Choi Youngjin , Lim Jun , Paik Seung‐R , Jung Seunho
Published: February 2009

The chiral separation of (±)‐catechin was investigated by capillary electrophoresis using characterized succinyl‐β‐cyclodextrins (Suc‐β‐CDs) with one to three degree of substitution values. The effects of nature and concentration of Suc‐β‐CDs and running buffer pH on the migration time and resolution of (±)‐catechin are discussed. All three kinds of Suc‐β‐CDs show a clear baseline separation of (±)‐catechin in capillary electrophoresis. Mono‐Suc‐β‐CD effectively separated (±)‐catechin, and additional substituted CDs (di‐ and tri‐Suc‐β‐CD) were capable of chiral separation at a broad pH range. The optimum running conditions were found to be 100 mM borate buffer (pH 9.8) containing 5 mM mono‐Suc‐β‐CD with no methanol organic modifier. Chirality, 2009. © 2009 Wiley‐Liss, Inc.
Synthesis, SAR, and Biological Evaluation of α‐Sulfonylphosphonic Acids as Selective Matrix Metalloproteinase Inhibitors
Authors: Rubino Maria Teresa , Agamennone Mariangela , Campestre Cristina , Fracchiolla Giuseppe , Laghezza Antonio , Loiodice Fulvio , Nuti Elisa , Rossello Armando , Tortorella Paolo
Published: February 2009

Selective MMP inhibitors: Eleven α‐sulfonylphosphonates were synthesized and tested as MMP inhibitors. The IC50 values for most of them are in the nanomolar range against MMP‐2, ‐8, ‐13, and ‐14, with an interesting selectivity profile versus MMP‐9.

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Eleven simple α‐sulfonylphosphonates, new analogues of previously reported α‐sulfonylaminophosphonates, were prepared and tested as MMP inhibitors. The IC50 values of most of these compounds are in the nanomolar range against MMP‐2, ‐8, ‐13, and ‐14. Compound 11 proved to be the most effective inhibitor of MMP‐2 (IC50=60 nM), with interesting selectivity versus the antitarget enzymes MMP‐3 and MMP‐9. The mode of binding of the new phosphonates in the active site of MMP‐2 was studied, and variations in inhibition was explained by means of molecular modeling.
Association of marijuana use and the incidence of testicular germ cell tumors
Authors: Daling Janet R. , Doody David R. , Sun Xiaofei , Trabert Britton L. , Weiss Noel S. , Chen Chu , Biggs Mary L. , Starr Jacqueline R. , Dey Sudhansu K. , Schwartz Stephen M.
Published: February 2009

BACKGROUND:

The incidence of testicular germ cell tumors (TGCTs) has been increasing the past 4 to 6 decades; however, exposures that account for this rise have not been identified. Marijuana use also grew during the same period, and it has been established that chronic marijuana use produces adverse effects on the human endocrine and reproductive systems. In this study, the authors tested the hypothesis that marijuana use is a risk factor for TGCT.

METHODS:

A population‐based, case‐control study of 369 men ages 18 to 44 years who were diagnosed with TGCT from January 1999 through January 2006 was conducted in King, Pierce and Snohomish Counties in Washington State. The responses of these men to questions on their lifetime marijuana use were compared with the responses of 979 age‐matched controls who resided in the same 3 counties during the case diagnosis period.

RESULTS:

Men with a TGCT were more likely to be current marijuana smokers at the reference date compared with controls (odds ratio [OR], 1.7; 95% confidence interval [95% CI], 1.1‐2.5). In analyses according to histologic type, most of the association between current marijuana use and TGCT was observed in men who had nonseminomas/mixed histology tumors (current use: OR, 2.3; 95% CI, 1.3‐4.0). Age at first use among current users (age <18 years [OR, 2.8] vs age ≥18 years [OR, 1.3]) and frequency of use (daily or weekly [OR, 3.0] vs less than once per week [OR, 1.8]) appeared to modify the risk.

CONCLUSIONS:

An association was observed between marijuana use and the occurrence of nonseminoma TGCTs. Additional studies of TGCTs will be needed to test this hypothesis, including molecular analyses of cannabinoid receptors and endocannabinoid signaling, which may provide clues regarding the biologic mechanisms of TGCTs. Cancer 2009. © 2009 American Cancer Society.
A new autosomal STR nineplex for canine identification and parentage testing
Authors: van Asch Barbara , Alves Cíntia , Gusmão Leonor , Pereira Vânia , Pereira Filipe , Amorim António
Published: February 2009

A single multiplex PCR assay capable of simultaneously amplifying nine canine‐specific autosomal STR markers (FH3210, FH3241, FH2004, FH2658, FH4012, REN214L11, FH2010, FH2361 and the newly described C38) was developed for individual identification and parentage testing in domestic dogs. In order to increase genotyping efficiency, amplicon sizes were optimized for a 90–350 bp range, with fluorescently labelled primers for use in Applied Biosystems, Inc., platforms. The performance of this new multiplex system was tested in 113 individuals from a case‐study population and 12 random dogs from mixed‐breed origin. Co‐dominant inheritance of STR alleles was investigated in 101 father, mother and son trios. Expected heterozygosity values vary between 0.5648 for REN214L11 and 0.9050 for C38. The high level of genetic diversity observed for most markers provides this multiplex with a very high discriminating power (matching probability=1.63/1010 and matching probability among siblings=4.9/103). Allele sequences and a proposal for standardized nomenclature are also herein presented, aiming at implementing the use of this system in forensic DNA typing and population genetic studies. This approach resulted in an optimized and well‐characterized canine DNA genotyping system that is highly performing and straightforward to integrate and employ routinely. Although this STR multiplex was developed for use and tested in a case‐study population, the Portuguese breed Cão de Gado Transmontano, it proved to be useful for general identification purposes or parentage testing.
Sequence‐related amplified polymorphism, an effective molecular approach for studying genetic variation inFasciolaspp. of human and animal health significance
Authors: Li Qiao‐Yan , Dong Shi‐Juan , Zhang Wei‐Yu , Lin Rui‐Qing , Wang Chun‐Ren , Qian De‐Xing , Lun Zhao‐Rong , Song Hui‐Qun , Zhu Xing‐Quan
Published: February 2009

In the present study, a recently described molecular approach, namely sequence‐related amplified polymorphism (SRAP), which preferentially amplifies ORFs, was evaluated for the studies of genetic variation amongFasciola hepatica,Fasciola giganticaand the “intermediate”Fasciolafrom different host species and geographical locations in mainland China. Five SRAP primer combinations were used to amplify 120Fasciolasamples after ten SRAP primer combinations were evaluated. The number of fragments amplified fromFasciolasamples using each primer combination ranged from 12 to 20, with an average of 15 polymorphic bandsperprimer pair. Fifty‐nine main polymorphic bands were observed, ranging in size from 100 to 2000 bp, and SRAP bands specific toF. hepaticaorF. giganticawere observed. SRAP fragments common toF. hepaticaand the “intermediate”Fasciola, or common toF. giganticaand the “intermediate”Fasciolawere identified, excised and confirmed by PCR amplification of genomic DNA using primers designed based on sequences of these SRAP fragments. Based on SRAP profiles, unweighted pair‐group method with arithmetic averages clustering algorithm categorized all of the examined representativeFasciolasamples into three groups, representing theF. hepatica, the “intermediate”Fasciola, or theF. gigantica. These results demonstrated the usefulness of the SRAP technique for revealing genetic variability betweenF. hepatica,F. giganticaand the “intermediate”Fasciola, and also provided genomic evidence for the existence of the “intermediate”FasciolabetweenF. hepatica andF. gigantica. This technique provides an alternative and a useful tool for the genetic characterization and studies of genetic variability in parasites.
Qualitative performance evaluation of torque control methods for industrial applications
Authors: Tripathi Anurag , Dwivedi Bharti , Chandra Dinesh
Published: February 2009

Robust control of torque has been a motivation for research in the servo and electric drives industry. For industrial drives and servo applications AC machine drives are gaining prominence over the conventional DC‐motor drives. Two methods, (a) field oriented control (FOC) and (b) the direct torque control (DTC) have been proposed to control an AC motor. FOC is a current control method and needs co‐ordinated transformation. Torque dynamic depends upon the modulator, which also decides the steady state performance. DTC on the other hand is more robust and has physically the fastest torque dynamic. These methods have succeeded in achieving a fast and dynamically decoupled torque control but at what expense? Problems of FOC are saturation of current controllers, current control in the overmodulation region, and parameter sensitivity. Problems with DTC are variable switching frequency and sampling period dependence of hysteresis controllers, during digital implementation. This paper highlights the problems and explains a method of achieving direct control of torque using a method of stator flux vector control. The analysis carried out here is backed with appropriate simulation results. Copyright © 2009 John Wiley & Sons, Ltd.
Pioglitazone promotes survival and prevents hepatic regeneration failure after partial hepatectomy in obese and diabetic KK-Ay mice #
Authors: Aoyama Tomonori , Ikejima Kenichi , Kon Kazuyoshi , Okumura Kyoko , Arai Kumiko , Watanabe Sumio
Published: February 2009

Pathogenesis of metabolic syndrome–related nonalcoholic steatohepatitis (NASH) involves abnormal tissue-repairing responses in the liver. We investigated the effect of pioglitazone, a thiazolidinedione derivative (TZD), on hepatic regenerative responses in obese, diabetic KK-Ay mice. Male KK-Ay mice 9 weeks after birth underwent two-thirds partial hepatectomy (PH) after repeated intragastric injections of pioglitazone (25 mg/kg) for 5 days. Almost half of the KK-Ay mice died within 48 hours of PH;however, mortality was completely prevented in mice pretreated with pioglitazone. In KK-Ay mice, bromodeoxyuridine (BrdU) incorporation to hepatocyte nuclei 48 hours after PH reached only 1%; however, pioglitazone pretreatment significantly increased BrdU-positive cells to 8%. Cyclin D1 was barely detectable in KK-Ay mice within 48 hours after PH. In contrast, overt expression of cyclin D1 was observed 24 hours after PH in KK-Ay mice pretreated with pioglitazone. Hepatic tumor necrosis factor alpha (TNF-α) messenger RNA (mRNA) was tremendously increased 1 hour after PH in KK-Ay mice, the levels reaching ninefold over C57Bl/6 given PH, whereas pioglitazone blunted this increase by almost three-fourths. Pioglitazone normalized hypoadiponectinemia in KK-Ay mice almost completely. Serum interleukin (IL)-6 and leptin levels were elevated extensively 24 hours after PH in KK-Ay mice, whereas the levels were largely decreased in KK-Ay mice given pioglitazone. Indeed, pioglitazone prevented aberrant increases in signal transducers and activators of transcription (STAT)3 phosphorylation and suppressor of cytokine signaling (SOCS)-3 mRNA in the liver in KK-Ay mice. Conclusion: These findings indicated that pioglitazone improved hepatic regeneration failure in KK-Ay mice. The mechanism underlying the effect of pioglitazone on regeneration failure most likely involves normalization of expression pattern of adipokines and subsequent cytokine responses during the early stage of PH. (Hepatology 2009.)
Age-related decrease in proteasome expression contributes to defective nuclear factor-κB activation during hepatic ischemia/reperfusion #
Authors: Huber Nadine , Sakai Nozomu , Eismann Thorsten , Shin Thomas , Kuboki Satoshi , Blanchard John , Schuster Rebecca , Edwards Michael J. , Wong Hector R. , Lentsch Alex B.
Published: February 2009

Hepatic ischemia/reperfusion (I/R) leads to liver injury and dysfunction through the initiation of a biphasic inflammatory response that is regulated by the transcription factor nuclear factor κB (NF-κB). We have previously shown that there is an age-dependent difference in the injury response to hepatic I/R in mice that correlates with divergent activation of NF-κB such that young mice have greater NF-κB activation, but less injury than old mice. In this study, we investigated the mechanism by which age alters the activation of NF-κB in the liver during I/R. Young (4-5 weeks) and old (12-14 months) mice underwent partial hepatic I/R. Livers were obtained for RNA microarray analysis and protein expression assays. Using microarray analysis, we identified age-dependent differences in the expression of genes related to protein ubiquitinylation and the proteasome. In old mice, genes that are involved in the ubiquitin-proteasome pathway were significantly down-regulated during I/R. Consistent with these findings, expression of a critical proteasome subunit, non-adenosine triphosphatase 4 (PSMD4), was reduced in old mice. Expression of the NF-κB inhibitory protein, IκBα, was increased in old mice and was greatly phosphorylated and ubiquitinylated. The data provide strong evidence that the age-related defect in hepatic NF-κB signaling during I/R is a result of decreased expression of PSMD4, a proteasome subunit responsible for recognition and recruitment of ubiquitinylated substrates to the proteasome. It appears that decreased PSMD4 expression prevents recruitment of phosphorylated and ubiquitinylated IκBα to the proteasome, resulting in a defect in NF-κB activation. (Hepatology 2009.)
L-ornithine and phenylacetate synergistically produce sustained reduction in ammonia and brain water in cirrhotic rats #
Authors: Davies Nathan A. , Wright Gavin , Ytrebφ Lars M. , Stadlbauer Vanessa , Fuskevåg Ole-Martin , Zwingmann Claudia , Davies Ceri D. , Habtesion Abeba , Hodges Stephen J. , Jalan Rajiv
Published: February 2009

Treatment of hyperammonemia and hepatic encephalopathy in cirrhosis is an unmet clinical need. The aims of this study were to determine whether L-ornithine and phenylacetate/phenylbutyrate (administered as the pro-drug phenylbutyrate) (OP) combined are synergistic and produce sustained reduction in ammonia by L-ornithine acting as a substrate for glutamine synthesis, thereby detoxifying ammonia, and the phenylacetate excreting the ornithine-derived glutamine as phenylacetylglutamine in the urine. Sprague-Dawley rats were studied 4 weeks after bile duct ligation (BDL) or sham operation. Study 1: Three hours before termination, an internal carotid sampling catheter was inserted, and intraperitoneal saline (placebo), OP, phenylbutyrate, or L-ornithine were administered after randomization. BDL was associated with significantly higher arterial ammonia and brain water and lower brain myoinositol (P < 0.01, respectively), compared with sham-operated controls, which was significantly improved in the OP-treated animals; arterial ammonia (P < 0.001), brain water (P < 0.05), brain myoinositol (P < 0.001), and urinary phenylacetylglutamine (P < 0.01). Individually, L-ornithine or phenylbutyrate were similar to the BDL group. In study 2, BDL rats were randomized to saline or OP administered intraperitoneally for 6 hours or 3, 5, or 10 days and were sacrificed between 4.5 and 5 weeks. The results showed that the administration of OP was associated with sustained reduction in arterial ammonia (P < 0.01) and brain water (P < 0.01) and markedly increased arterial glutamine (P < 0.01) and urinary excretion of phenylacetylglutamine (P < 0.01) in each of the OP treated groups. Conclusion: The results of this study provide proof of the concept that L-ornithine and phenylbutyrate/phenylacetate act synergistically to produce sustained improvement in arterial ammonia, its brain metabolism, and brain water in cirrhotic rats. (Hepatology 2009.)