bluuebunny/crossref_metadata_2025 huggingface dataset:
ChemInform Abstract: UV Photoinduced Dynamics in Protonated Aromatic Amino Acid
Authors: Gregoire G. , Lucas B. , Barat M. , Fayeton J. A. , Dedonder‐Lardeux C. , Jouvet C.
Published: August 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: Synthesis, Chemical Properties and Biological Activities of Cyclic Bis(3′‐5′)diguanylic Acid (c‐Di‐GMP) and Its Analogues
Authors: Hyodo Mamoru , Hayakawa Yoshihiro
Published: August 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: 5‐Substituted Nucleosides in Biochemistry and Biotechnology
Authors: Ahmadian Mohammad , Bergstrom Donald E.
Published: August 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: The Properties of 4′‐Thionucleosides
Authors: Yokoyama Masataka
Published: August 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: Importance of Backbone and Solvent Properties for Conformational Dynamics in Polypeptides
Authors: Doose Soeren
Published: August 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: Investigation on the Beckmann Rearrangement Reaction Catalyzed by Porous Solids: MAS NMR and Theoretical Calculations
Authors: Lezcano‐Gonzalez Ines , Boronat Mercedes , Blasco Teresa
Published: August 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.
369 Tflop/s molecular dynamics simulations on the petaflop hybrid supercomputer ‘Roadrunner’
Authors: Germann Timothy C. , Kadau Kai , Swaminarayan Sriram
Published: August 2009

We describe the implementation of a short‐range parallel molecular dynamics (MD) code, SPaSM, on the heterogeneous general‐purpose Roadrunner supercomputer. Each Roadrunner ‘TriBlade’ compute node consists of two AMD Opteron dual‐core microprocessors and four IBM PowerXCell 8i enhanced Cell microprocessors (each consisting of one PPU and eight SPU cores), so that there are four MPI ranks per node, each with one Opteron and one Cell. We will briefly describe the Roadrunner architecture and some of the initial hybrid programming approaches that have been taken, focusing on the SPaSM application as a case study. An initial ‘evolutionary’ port, in which the existing legacy code runs with minor modifications on the Opterons and the Cells are only used to compute interatomic forces, achieves roughly a 2× speedup over the unaccelerated code. On the other hand, our ‘revolutionary’ implementation adopts a Cell‐centric view, with data structures optimized for, and living on, the Cells. The Opterons are mainly used to direct inter‐rank communication and perform I/O‐heavy periodic analysis, visualization, and checkpointing tasks. The performance measured for our initial implementation of a standard Lennard–Jones pair potential benchmark reached a peak of 369 Tflop/s double‐precision floating‐point performance on the full Roadrunner system (27.7% of peak), nearly 10× faster than the unaccelerated (Opteron‐only) version. Copyright © 2009 John Wiley & Sons, Ltd.
Neural correlates of successful and partial inhibitions in children: An ERP study
Authors: Cragg Lucy , Fox Allison , Nation Kate , Reid Corinne , Anderson Mike
Published: August 2009

This experiment used event‐related potentials (ERPs) to investigate the neural processes underlying the development of response inhibition in a modified version of the go/no‐go paradigm [Cragg and Nation [2008] Developmental Science 11(6): 819–827]. N2 and P3 ERP components on correct go trials and partial and successful inhibitions were compared in 7‐ and 9‐year‐old children. A larger N2 effect on successful inhibitions was found in 9‐year‐olds compared to 7‐year‐olds at fronto‐central electrodes. N2 amplitude was positively related to behavioral performance in the 7‐year‐olds suggesting it may reflect inhibitory processes; however, this relationship was not present in the 9‐year‐olds. Age differences were also apparent in the go P3, perhaps indicating differences in stimulus processing. The no‐go P3 component was larger on successful than partial inhibitions. In contrast, there was no difference in N2 amplitude between partial and successful inhibitions. A significant difference was found in N2 latency however. This suggests that inhibitory processes are similar in both cases but initiated earlier on successful inhibitions. N2 latency was also shorter in 9‐year‐olds than 7‐year‐olds supporting an increase in the efficiency of response inhibition with age. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 533–543, 2009.
InIII and GaIII Complexes of Sugar‐Substituted Tripodal Trisalicylidene Imines: The First 68Ga‐Labelled Sugar Derivative
Authors: Gottschaldt Michael , Bohlender Carmen , Pospiech Anne , Görls Helmar , Walther Martin , Müller Dirk , Klette Ingo , Baum Richard P. , Schubert Ulrich S.
Published: August 2009

Gallium and indium complexes derived from salicylaldimines of 1,1,1‐tris(aminomethyl)ethane (TAME) with pendantxylose, glucose and galactose units have been synthesised as model compounds for potential application as radiotracers. The formed neutral complexes have been characterised by NMR spectroscopy, elemental analysis, mass spectrometry and, in the case of the galactose‐bearing InIII complex, by single‐crystal X‐ray structure analysis. Octahedral coordination was observed with the appearance of an equilibrium of Λ‐ and Δ‐isomers at the metal centre. The glucose‐appended ligand was radiolabelled with 68GaIII ions in up to 98 % yield depending on the prevailing pH value. The in vitro stability of the radioactive complex was examined by challenge experiments against apo‐transferrin and blood plasma. Very high stability was observed; even after a period of 2 h, 90 % of the complex could still be detected. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Ligand‐Free Iron/Copper‐Cocatalyzed Amination of Aryl Iodides
Authors: Wu Xiao‐Feng , Darcel Christophe
Published: August 2009

The Fe2O3/CuI system efficiently catalyzes the direct amination of aryl iodides with aqueous ammonia in ethanol at 90 °C under aerobic conditions. No ligand was used to perform such reaction. A very wide variety of functional groups was tolerated on the aryl iodide partner. This procedure is economically and environmentally attractive as a result of the use of aqueous ammonia and ethanol.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Enhancement of the Electrochemical Performance of Prussian Blue Modified Electrode via Ionic Liquid Treatment
Authors: Zhang Ling , Song Zhining , Zhang Qian , Jia Xiaoguang , Zhang Hongbo , Xin Shigang
Published: August 2009

This article first reports the preparation of a Prussian blue (PB) modified electrode with improved electrochemical properties at the functionalized glass carbon electrode (GC) by imidazolium based ionic liquid. The molecular ionic liquid film on the GC electrode has been found to influence the electrodeposition of PB by a way of enhancement of voltammetric currents, suggesting efficient electrodepositon. Such efficient electrodeposition was caused by the static electric effect which existed between the positively charged imidazolium group on the electrode surface and the negative ferric‐ferricyanide in solution. Compared with the PB/GC electrode, the PB/[Bmim][Cl]/GC electrode showed much better electrochemical stability after successive potential cycling for 250 cycles. A comparative study on amperometric responses of both electrodes to reduce H2O2 was also investigated. PB/[Bmim][Cl]/GC electrode showed a better electrocatalytic performance to H2O2 with wider linear detection range and higher sensitivity than that at the electrode without [Bmim][Cl]. Furthermore, the kinetics for both electrodes was discussed. The PB/[Bmim][Cl]/GC electrode possessed a greater diffusion coefficient.
Voltammetric Determination of 4‐Nitrophenol Using a Novel Type of Silver Amalgam Paste Electrode
Authors: Niaz Abdul , Fischer Jan , Barek Jiří , Yosypchuk Bogdan , Sirajuddin  , Bhanger Muhammad Iqbal
Published: August 2009

A differential pulse voltammetric (DPV) method was developed for the determination of 4‐nitrophenol (4‐NP) at a newly developed silver amalgam paste electrode (AgA‐PE) in Britton–Robinson buffer pH 3.0. The electrode is based on a disposable plastic pipette tip filled with paste amalgam based on a mixture of mercury and fine silver powder (9 : 1, w/w). The experimental parameters, such as pH of Britton–Robinson buffer and activation and regeneration potential of the electrode surface were optimized. The reduction peak current dependences were linear for the concentration of 4‐NP from 0.2 to 100 μM. The method showed reproducible results with RSD (n=45) of 1.7%. The limit of determination (LOD) was 0.3 μM. The method was successfully applied for the direct determination of 4‐NP in drinking water.
Sperm protein 17 is a novel marker for predicting cisplatin response in esophageal squamous cancer cell lines
Authors: Kausar Tasneem , Ahsan Aarif , Hasan Md. Raghibul , Lin Lin , Beer David G. , Ralhan Ranju
Published: August 2009

Expression of sperm protein 17 (Sp17) mRNA has been reported in various malignancies. In an earlier study, we reported the upregulation of Sp17 transcripts in primary esophageal squamous cell carcinomas (ESCCs) using differential display and detected Sp17 transcripts in 86% of ESCCs by RT‐PCR, whereas no transcripts were detected in the paired normal esophageal tissues. Herein we hypothesized that Sp17 might be used as a marker for detecting the response of anticancer therapies in ESCCs. Our results indicated that Sp17 protein levels in esophageal squamous cancer cell lines decreased in response to treatment with (i) the HSP90 activity inhibitor geldanamycin, (ii) the tyrosine kinase inhibitor erlotinib and (iii) cisplatin (chemotherapeutic agent commonly used in management of ESCC). In contrast, the Sp17 levels did not decrease in response to radiation therapy and treatment with the chemotherapeutic agent, gemcitabine. Further investigations showed that cisplatin induced decrease in Sp17 levels was due to transcriptional inhibition and cisplatin‐resistant cell lines did not show this decrease in Sp17 levels in response to cisplatin treatment. In addition, we also carried our mass spectophotometric analysis to identify the binding partners of Sp17 to characterize its possible involvement in esophageal tumorigenesis and chemoresistance.
Separation and recovery of cellulose and lignin using ionic liquids: a process for recovery from paper‐based waste
Authors: Lateef Huma , Grimes Sue , Kewcharoenwong Pajaree , Feinberg Benjamin
Published: August 2009

BACKGROUND: The production of paper makes use of cellulose and lignin as a raw material, and almost all cellulose and lignin production comes from raw wood materials, contributing to deforestation and resulting in potential environmental harm. It is therefore beneficial to develop technologies for cellulose and lignin recovery for re‐use and sustainability of resources.

RESULTS: Three imidazolium based ionic liquids (ILs), 1‐(2‐cyanoethyl)‐3‐methylimidazolium bromide (cyanoMIMBr), 1‐propyl‐3‐methylimidazolium bromide (propylMIMBr) and 1‐butyl‐3‐methylimidazolium chloride (butylMIMCl), were synthesised by microwave technology and fully characterised by mass spectrometry, thermogravimetric differential scanning calorimetry, thin layer chromatography, nuclear magnetic resonance and Fourier transform infrared spectroscopies. Cellulose and lignin were soluble in all three ILs with solubility being greatest in cyanoMIMBr. Regeneration of cellulose and lignin was achieved from saturated solutions of cellulose in IL and lignin in IL for all three ILs. The ILs propylMIMBr and butylMIMBr have been used for the first time in the separation and recovery of cellulose and lignin and regeneration of the IL from a mixture of cellulose and lignin in IL. FTIR analysis confirms successful recovery.

CONCLUSIONS: This work demonstrates the ability of ILs to separate and recover cellulose and lignin from a mixed system. Copyright © 2009 Society of Chemical Industry
Nitrate‐dependent degradation of 17α‐ethinylestradiol by acclimated activated sludge under anaerobic conditions
Authors: Zeng Qingling , Li Yongmei , Gu Guowei
Published: August 2009

BACKGROUND: The synthetic estrogen 17α‐ethinylestradiol (EE2) is of great environmental concern. Batch experiments were conducted to investigate the removal of EE2 by activated sludge under anaerobic conditions with or without nitrate. The effect of temperature on EE2 removal was also estimated.

RESULTS: No biodegradation of EE2 was observed in the absence of nitrate; owing to sorption onto the activated sludge, the overall removal EE2 rate was 62%; the sorption was fitted to both Freundlich and linear sorption models; the sorption rate decreased with the increase temperature. In the presence of nitrate, the overall removal rate of EE2 was greater than 97% after 72 h, mostly from biodegradation (95%); the biodegradation could be described by first‐order reaction kinetics with average rate constant of 0.0344 h−1; increasing temperature enhanced the rate constant and the removal rate could be as high as 96–98% in the temperature range 10–30 °C.

CONCLUSION: EE2 was removed by activated sludge under anaerobic conditions. In the absence of nitrate, the removal of EE2 was a result of sorption onto activated sludge. In the presence of nitrate, biodegradation was the dominant process for EE2 removal. Higher temperature improves biodegradation rate, but reduces the sorption of EE2 onto activated sludge. Copyright © 2009 Society of Chemical Industry
The oxidative degradation of sulfadiazine at the interface of α‐MnO2 and water
Authors: Dong Jun , Li Yongtao , Zhang Lijia , Liu Chengshuai , Zhuang Li , Sun Lina , Zhou Jianmin
Published: August 2009

BACKGROUND: Sulfadiazine (SD), a widely used antibiotic chemical, has been detected in contaminated water and soils. Manganese dioxides are common minerals with a high redox potential and can act as active oxidants for SD degradation in wastewater treatment.

RESULTS: α‐MnO2 was used to promote SD oxidative degradation. At pH 4.6 and 25 °C, 92.7% of SD (0.02 mmol L−1) was degraded by 1.0 g L−1α‐MnO2. SO42− was detected as the inorganic end product from the mineralization of SD. The ecological toxicity index of average well color development (AWCD) in SD solution was 2.01 after the solution was degraded by α‐MnO2 for 2 h, while the AWCD was 0.48 for the solution without α‐MnO2 treatment. The degradation rate of SD can be improved by increasing the dosages of α‐MnO2 and the reaction temperature, but the rate was limited by increased initial SD concentration and reaction pH.

CONCLUSION: SD can be effectively degraded and mineralized with α‐MnO2. These results are helpful for removing antibiotics by manganese dioxides in the environment, and also for exploring new technology for wastewater treatment. Copyright © 2009 Society of Chemical Industry
Risk bartering: what post‐M&A integration teams really do
Authors: Harwood Ian A. , Chapman Chris B.
Published: August 2009

This study is based on a £240m post‐merger and acquisition integration project within an FTSE100 pharmaceutical manufacturing supply chain network which was successfully implemented over a four‐year period.

By adopting a grounded theory methodology, the research identifies phenomena that occurred within the integration teams to give insights into ‘what is going on here?’

Through constant comparison analytical techniques, the research develops a substantive theory of ‘risk bartering,’ which explains how key individuals engaged and negotiated with each other, resulting in mutually acceptable integration scenarios, with risk being used as an underlying trading ‘currency.’ This provides novel insights into the role of risk in M&A integration change programs.

Copyright © 2009 John Wiley & Sons, Ltd.
Globalfocusing: corporate strategies under pressure
Authors: Meyer Klaus E.
Published: August 2009

On the global stage, competitive advantages are gained by creating, transferring, and exploiting competences across operations and locations internationally.

In consequence, conglomerates are redesigning their strategies to focus on core businesses, yet with a global scope. De‐diversification and internationalization thus complement each other in a process of ‘globalfocusing.’

This paper outlines the shifts in the relative barriers to entry to countries and industries that have been driving these processes of change in corporate strategies on the global stage.

On this basis, implications of the change in global strategy are derived for decision‐makers in both business and politics who are operating in the volatile global economy.

Copyright © 2009 John Wiley & Sons, Ltd.
Quality management: a fixture or a vital process?
Authors: Murphy William H. , Leonard Denis
Published: August 2009

We address the current status of quality management (QM) in companies in this paper.

Interviews with senior executives of 19 companies spanning multiple industries and company sizes indicate that there are now at least five recurring themes related to QM's current role in companies:

— Realized gains from QM keep it a fixture at most companies.

— The aim of well‐serving customers is appropriately integrated into quality efforts.

— The realization that pursuit of QM solely for the sake of winning awards can have harmful consequences.

— QM's emphasis on self‐assessment and quality models is seen as valuable for providing focus and direction.

— Gaps in integrating QM beyond operations exist in most companies.

Our findings suggest that most businesses continue to have substantial opportunities for improvement in terms of more fully engaging QM throughout the firm. This makes it imperative that strategists engage and ultimately evolve companies so as to achieve their full potential. QM is not a fad of the century just past. Instead, it is a powerful means for companies to continue on a path to superior performance.

Copyright © 2009 John Wiley & Sons, Ltd.
Comparison of normal and low‐lignin hull/high‐oil groat oat as energy sources for broiler chicks
Authors: Thacker Philip A , Widyaratne Gemunu P , Rossnagel Brian G
Published: August 2009

BACKGROUND: Oats are not widely utilised in poultry rations. The principal reason for this is their high fibre content. Fibre is not very digestible by poultry and its presence impairs the digestibility of energy and other nutrients. A new low‐lignin hull/high‐oil groat (LLH/HOG) oat was developed recently and the present study was conducted to determine its nutritional value for poultry.

RESULTS: In experiment 1, gain of broiler chicks fed the control was higher (P < 0.01) than that of birds fed normal oat. Gain and intake of birds fed LLH/HOG oat were superior (P < 0.01) to those of birds fed normal oat. Feed conversion (FC) was higher for birds fed the control than for birds fed normal oat (P < 0.01), while FC for birds fed the control and LLH/HOG oat did not differ (P > 0.05). FC was better for birds fed LLH/HOG than for birds fed normal oat (P < 0.01). In experiment 2, weight gain (P < 0.01), feed intake (P < 0.01) and FC (P = 0.07) declined as the level of LLH/HOG oat in the diet increased.

CONCLUSION: Feeding LLH/HOG oat to broilers improved weight gain and FC compared with feeding normal oat. These results give a strong indication that LLH/HOG oat is superior to normal oat as an energy source for poultry. However, despite improvements in chemical composition, LLH/HOG oat is still inferior to wheat for use in broiler rations. Copyright © 2009 Society of Chemical Industry
Effects of citric acid supplementation on rumen fermentation, urinary excretion of purine derivatives and feed digestibility in steers
Authors: Wang Cong , Liu Qiang , Meng Jie , Yang Wen Zhu , Yang Xiao Min , He Dong Chang , Dong Kuan Hu , Huang Ying Xiang
Published: August 2009

BACKGROUND: An increase feed efficiency and rate of gain were observed from addition of sodium citrate to the diet of fatting lamb. It is suggested that the small amounts of citric acid (CA) may have a catalytic effect on rumen microbial metabolism which would result in a potential means of increasing feed efficiency. The objective was to evaluate the effects of CA supplementation on rumen fermentation, ruminal microbial production by measuring urinary excretion of purine derivatives, and digestibility in the total tract of steers.

RESULTS: Ruminal pH linearly (P = 0.01) decreased, whereas total volatile fatty acid concentration linearly (P = 0.01) increased with increasing CA supplementation. Ratio of acetate to propionate linearly (P = 0.01) increased due to the increase in acetate production. Urinary excretion of purine derivatives was quadratically (P = 0.02) changed, with the lowest for control, medium for low CA and highest for medium and high CA supplementation. Similarly, digestibilities of nutrients in the total tract were also linearly and quadratically increased with increasing dosages of CA.

CONCLUSION: Supplementation of CA increased rumen acetate concentration and thus increased ratio of acetate to propionate. Urinary excretion of purine derivatives and total digestibility were improved. In the experimental conditions of this trial, the optimum citric acid dose was about 200 g citric acid per steer per day. Copyright © 2009 Society of Chemical Industry
Identification of repressed gene transcript accumulation in three albino mutants of Bambusa edulis Munro by cDNA microarray analysis
Authors: Wu Fu‐Hui , Liu Nien‐Tze , Chou Shu‐Jen , Shen Shu‐Chen , Chang Bill Chia‐han , Pan Chao‐Yu , Lin Choun‐Sea
Published: August 2009

BACKGROUND: Bamboo is an economically important market vegetable and processed food product in Asia. An accelerated growth rate and increased photosynthesis efficiency would be valuable agronomic traits in commercial bamboo culture. Tissue culture‐derived albino mutants can be used as experimental material to investigate this phenomenon, but the current body of genetic information available on bamboo is very limited.

RESULTS: A cDNA library was constructed from in vitro shoots of Bambusa edulis Munro and subsequently used in a bamboo microarray analysis to investigate the gene profiles of three albino mutants (ab, ab1, ab2) cultured under light/dark and dark conditions. Analysis of the array data suggested that no gene transcript accumulation was significantly upregulated, but that transcript accumulation of 24 genes was downregulated by <50% relative to the wild type. This repression was determined to be light‐independent as these genes were also repressed when ab mutant shoots were incubated in the dark. Microarray analysis of the light sensitivity of specific gene expression of the mutant ab and wild type shoots identified 14 genes as being highly expressed when cultured in the light, 12 of which showed a similar response to light in both the wild type and ab mutant. The transcripts of a group of bamboo‐specific genes (three isoforms) accumulated less in all albino mutants, and another group of bamboo‐specific genes (six isoforms) accumulated less under dark conditions. The microarray results were confirmed by reverse transcriptase polymerase chain reaction. Using the rice protoplast transformation, the products of the bamboo‐specific albino‐repressed gene 09A06 were found to be localized to the chloroplast.

CONCLUSION: A Bambusa edulis shoot cDNA library was used to establish a bamboo microarray, which successfully identified gene transcripts that were repressed in the albino mutants. The subcellular localization of these bamboo‐specific gene products was identified by rice protoplast transient expression, where 09A06 accumulated around the chloroplast. Copyright © 2009 Society of Chemical Industry
Layer‐by‐Layer Nano‐Encapsulation of Microbes: Controlled Cell Surface Modification and Investigation of Substrate Uptake in Bacteria
Authors: Franz Bettina , Balkundi Shantanu S. , Dahl Christiane , Lvov Yuri M. , Prange Alexander
Published: August 2009

LbL nano self‐assembly coating of A. vinosum with different polyelectrolyte combinations is presented as an example to investigate substrate uptake in bacteria. The effects of surface charge and the formation of a physical barrier provides new insights in the contact mechanisms between the cell surface and insoluble elemental sulfur. Furthermore, uptake of sulfide by encapsulated cells was investigated. Growth experiments of coated cells showed that surface charge did neither affect sulfide uptake nor the contact formation between the cells and solid sulfur. However, increasing layers slowed or inhibited the uptake of sulfide and elemental sulfur. This work demonstrates how defining surface properties of bacteria has potential for microbiological and biotechnological applications.

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Antitumor Efficacy of Colon‐Specific HPMA Copolymer/9‐Aminocamptothecin Conjugates in Mice Bearing Human‐Colon Carcinoma Xenografts
Authors: Gao Song‐Qi , Sun Yongen , Kopečková Pavla , Peterson C. Matthew , Kopeček Jindřich
Published: August 2009

The antitumor activity of a colon‐specific N‐(2‐hydroxypropyl)methacrylamide (HPMA) copolymer – 9‐aminocamptothecin (9‐AC) conjugate (P‐9‐AC) was assessed in orthotopic and subcutaneous animal (HT29 xenograft) tumor models. P‐9‐AC treatment of mice bearing orthotopic colon tumors, with a dose of 3 mg/kg of 9‐AC equivalent every other day for 6 weeks, resulted in regression of tumors in 9 of 10 mice. A lower dose of P‐9‐AC (1.25 mg/kg of 9‐AC equivalent) every other day for 8 weeks inhibited subcutaneous tumor growth in all mice. No liver metastases were observed. Colon‐specific release of 9‐AC from polymer conjugates enhanced antitumor activity and minimized the systemic toxicity.

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Biosensing with Functionalized Single Asymmetric Polymer Nanochannels
Authors: Ali Mubarak , Schiedt Birgitta , Neumann Reinhard , Ensinger Wolfgang
Published: August 2009

In this work, we describe the direct covalent attachment of protein recognition elements (biotin) with the carboxyl groups present on the walls of polyimide nanochannels. Subsequently, these biotinylated channels were used for the bio‐specific sensing of protein analytes. Moreover, surface charge of these asymmetric nanochannels was reversed from negative to positive via the conversion of carboxyl groups into terminated amino groups. The negatively charge (carboxylated) and positively charged (aminated) channels were further used for the electrochemical sensing of bovine serum albumin (BSA, pI = 4.7). These biorecognition events were assessed from the changes in the ionic current flowing through the nanochannel.

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A Biomimetic Chemical Approach to Facile Preparation of Large‐Area, Patterned, ZnO Quantum Dot/Polymer Nanocomposites on Flexible Plastics
Authors: Zou Shengli , Bai Huadong , Yang Peng , Yang Wantai
Published: August 2009

This study reports a new biomimetic approach to fabricate ZnO quantum dots (QDs) directed by surface‐immobilized acidic‐polymer brushes. Through multiple characterization methods including XPS, high‐resolution TEM, SEM, AFM, XRD, UV‐vis absorption and fluorescence spectroscopy, we found that surface‐photografted poly(acrylic acid) chains could mediate the heterogeneous nucleation and growth processes of zinc precursors to obtain ZnO QDs with a diameter of 4–5 nm. These QDs show quantum effects such as a blue shift of the excitation energy and enhanced UV emission, and more importantly, could be further formed in situ within the polymer matrix to fabricate transparent inorganic/organic hybrid nanocomposites and large‐area arrays on flexible plastic (poly(propylene)) substrate. It is expected that the results presented could instantly raise interest in the research and industrial fields, such as polymer‐supported advanced technologies, ZnO nanocrystals, biomineralization, and macroelectronics.

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Self‐Assembly and Photoresponsivity Property of Amphiphilic ABA Triblock Copolymers Containing Azobenzene Moieties in Dilute Solution
Authors: Tang Xinde , Gao Longcheng , Fan Xinghe , Liang Xiaochao , Zhou Qifeng
Published: August 2009

The self‐assembly and photoresponsivity of amphiphilic azobenzene‐containing ABA triblock copolymers PA6Cm‐b‐PEGn‐b‐PA6Cmsynthesized by atom transfer radical polymerization (ATRP) were reported. Different self‐assembly morphologies formed by the gradual addition of water to the copolymer solutions in THF. The formation process and aggregate morphology were characterized by UV–Visible spectroscopy and transmission electron microscope (TEM). The triblock copolymers start to form aggregates at the critical water content (CWC). With the addition of water, the aggregates show different morphologies, such as spherical micelles, vesicles, network‐like aggregates, and colloidal spheres, which involves the transformation between primary and secondary aggregates and the association/disassociation of aggregates. Photoresponsive property and aggregation behavior of these copolymers in solution under UV–Visible light irradiation were also investigated.

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Effect of Processing Variables on the Morphology of Electrospun Poly[(lactic acid)‐co‐(glycolic acid)] Nanofibers
Authors: Liu Fujuan , Guo Rui , Shen Mingwu , Wang Shanyuan , Shi Xiangyang
Published: August 2009

A systematic study of the effects of $\overline M _{\rm w}$, flow rate, voltage, and composition on the morphology of electrospun PLGA nanofibers is reported. It is shown that changes of voltage and flow rate do not appreciably affect the morphology. However, the $\overline M _{\rm w}$ of PLGA predominantly determines the formation of bead structures. Uniform electrospun PLGA nanofibers with controllable diameters can be formed through optimization. Further, multi‐walled carbon nanotubes can be incorporated into the PLGA nanofibers, significantly enhancing their tensile strength and elasticity without compromising the uniform morphology. The variable size, porosity, and composition of the nanofibers are essential for their applications in regenerative medicine.

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1D to 3D NMR study of microporous alumino‐phosphate AlPO4‐40
Authors: Morais Cláudia M. , Montouillout Valérie , Deschamps Michael , Iuga Dinu , Fayon Franck , Paz Filipe A. A. , Rocha João , Fernandez Christian , Massiot Dominique
Published: August 2009

From one‐ to two‐ and three‐dimensional MAS NMR solid‐state experiments involving 31P and 27Al, we show that the structure of microporous alumino‐phosphate AlPO4‐40 contains at least four times more sites than expected, and we attribute two types of AlIV sites. The newly described 27Al‐31P MQ‐HMQC opens new possibilities of describing details of three‐dimensional bounded networks. Copyright © 2009 John Wiley & Sons, Ltd.
On‐line acoustic attenuation spectroscopy of emulsions stabilized by vinyl alcohol–vinyl acetate copolymers: a model system for the suspension polymerization of vinyl chloride
Authors: Boscher Virginie , Helleboid Renaud , Lasuye Thierry , Stasik Bernard , Riess Gérard
Published: August 2009

BACKGROUND: Poly[(vinyl alcohol)‐co‐(vinyl acetate)] (PVA) copolymers obtained by partial hydrolysis of poly(vinyl acetate) are currently used as industrial stabilizers in the suspension polymerization of vinyl chloride monomer (VCM). Their molecular characteristics, mainly the average degree of hydrolysis (DH) and average degree of polymerization (DPw), have a major influence on the monomer droplet size and the properties of the final poly(vinyl chloride) resin.

RESULTS: The average droplet size and size distribution of chlorobutane/water emulsions, as a model system for VCM/water emulsions, were studied using acoustic attenuation spectroscopy on‐line with an agitated laboratory reactor. The emulsions were stabilized by PVA with DH values between 73 and 88 mol% and DPw values between 450 and 2500. The effects of agitation speed, stirring time and concentration of the PVA copolymers were investigated. An attempt was made to correlate the interfacial tension and the droplet size.

CONCLUSION: On‐line acoustic spectroscopy appears to be a suitable technique for the real‐time control of the droplet size of monomer suspensions. The advantages and limitations of the technique are outlined. The validity and the application limits of the commonly cited correlation between the droplet size and the Weber number are established for polymeric surfactant‐stabilized emulsions. Copyright © 2009 Society of Chemical Industry
Preparation and properties of core–shell alginate–carboxymethylchitosan hydrogels
Authors: Abreu Flávia OMS , Bianchini Carla , Kist Tarso BL , Forte Maria Madalena C
Published: August 2009

BACKGROUND: Hydrogels of alginate (ALG) with partially carboxymethylated chitosan (CMCHI) have been produced for drug delivery, based on the interactions between the negative groups and an ionic crosslinker. In the present work, CMCHI was used to evaluate the influence of amino groups that are positively charged at pH = 4 and 6 on the ALG–CMCHI core–shell hydrogel preparation. An ANOVA statistics tool was used to evaluate the effect of composition, pH and chitosan chemical nature on the morphology and swelling properties of the hydrogels in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF).

RESULTS: The ALG–CMCHI core–shell hydrogels presented smaller (ca 2.3 µm) and more homogeneous microparticles than those with unmodified chitosan (ca 5.5 µm). The ALG–CMCHI hydrogels showed higher thermal stability and lower degree of swelling in SGF (314%) compared to those with chitosan (708%), since in the former hydrogels the protective layers that surround the particles are negatively charged.

CONCLUSION: CMCHI can replace chitosan in the production of core–shell hydrogels with improved properties since the negative charge surrounding the ALG–CMCHI particles favours a lower degree of swelling. The results point out a possible prevention of burst release in SGF, sustaining the swelling ability of the ALG–CMCHI core–shell hydrogels in SIF, promising appropriate drug release. Copyright © 2009 Society of Chemical Industry
Synthesis and characterization of novel aromatic polyamides derived from 2,2′‐bis(p‐phenoxyphenyl)‐4, 4′‐diaminodiphenyl ether
Authors: Behniafar Hossein , Khosravi‐borna Saeed
Published: August 2009

BACKGROUND: Wholly aromatic polyamides (aramids) are high‐performance polymeric materials with outstanding heat resistance and excellent chemical stabilities due to chain stiffness and intermolecular hydrogen bonding of amide groups. Synthesis of structurally well‐designed monomers is an effective strategy to prepare modified forms of these aramids to overcome lack of organo‐solubility and processability limitations.

RESULTS: A novel class of wholly aromatic polyamides was prepared from a new diamine, namely 2,2′‐bis(p‐phenoxyphenyl)‐4,4′‐diaminodiphenyl ether (PPAPE), and two simple aromatic dicarboxylic acids. Two reference polyamides were also prepared by reacting 4,4′‐diaminodiphenyl ether with the same comonomers under similar conditions. M̄w and M̄n of the resultant polymers were 8.0 × 104 and 5.5 × 104 g mol−1, respectively. Polymers resulting from PPAPE exhibited a nearly amorphous nature. These polyamides exhibited excellent organo‐solubility in a variety of polar solvents and possessed glass transition temperatures up to 200 °C. The 10% weight loss temperatures of these polymers were found to be up to 500 °C under a nitrogen atmosphere. The polymers obtained from PPAPE could be cast into transparent and flexible films from N,N‐dimethylacetamide solution.

CONCLUSION: The results obtained show that the new PPAPE diamine can be considered as a good monomer to enhance the processability of its resultant aromatic polyamides while maintaining their high thermal stability. The observed characteristics of the polyamides obtained make them promising high‐performance polymeric materials. Copyright © 2009 Society of Chemical Industry
Isospecific polymerization of vinyl ethers with titanium catalysts containing modified tridentate anionic donor ligands
Authors: Sudhakar Padmanabhan , Vijayakrishna Kari
Published: August 2009

BACKGROUND: Stereo‐regulated polymerization of vinyl ethers (VEs) assumes significance because of its elegance and the resultant unique polymer properties. Although several Lewis acid catalysts polymerize VEs with good control of molecular weight, achieving stereo‐regularity is quite challenging. There are literature reports of a few catalyst systems capable of producing highly isotactic poly(vinyl ether) (PVE) only at lower temperatures with the polymer becoming atactic with an increase in reaction temperature. Hence innovating new catalyst systems which can produce highly stereo‐regular PVEs with high molecular weight at ambient temperature is quite challenging.

RESULTS: We used two different titanium pre‐catalysts (1‐TiCl2 and 2‐TiCl2) for the polymerization of VEs. These pre‐catalysts in combination with methylaluminoxane (MAO)/borate polymerized VEs in higher conversions. Highly isotactic poly(n‐butylvinyl ether) (PBVE; 75% dyad isotactic ratio) was obtained with 1‐TiCl2/MAO at ambient temperature.

CONCLUSION: We synthesized unimodal and highly isotactic PBVE with molecular weights of the order of 105 g mol−1 using the non‐metallocene‐type single‐site catalyst system 1‐TiCl2/MAO even at ambient temperature. The symmetry around the metal centre in the pre‐catalyst and the polymerization temperature played a major role in controlling the stereo‐regularization of the olefin inserted. Copyright © 2009 Society of Chemical Industry
Growth of scandium aluminum nitride nanowires on ScN(111) films on 6H‐SiC substrates by HVPE
Authors: Bohnen Tim , van Dreumel Gerbe W. G. , Hageman Paul R. , Algra Rienk E. , van Enckevort Willem J. P. , Vlieg Elias , Verheijen Marcel A. , Edgar James H.
Published: August 2009

The formation of ScAlN nanowires on ScN/6H‐SiC(0001) by hydride vapor phase epitaxy (HVPE) was analyzed. The diameters and lengths of the nanowires were 50 to 150 nm and 1 µm, respectively. The nanowires had a Al/Sc metal ratio of 95/5 as measured by energy dispersive analysis of X‐rays (EDX). The 4.84 Å unit cell periodicity along the length of the ScAlN nanowires was similar to that of pure AlN (4.98 Å), as measured by Fourier transforms of high resolution transmission electron microscopy images of a single nanowire. Only the (111) and (222) peaks of the ScN continuous film and the (0006) of the 6H‐SiC substrate were detected by θ‐2θ X‐ray diffraction. A tentative model, based on catalyst‐induced growth, is proposed to explain the unintentional formation of nanowires on the ScN film. This model is based on the production of volatile Al (possibly AlCl) by the reaction of the scandium metal source with the alumina reactor tube and subsequent reaction with hydrogen chloride. This reacts with ammonia in the deposition zone to create ScAlN nanowires, catalyzed by small ScAl clusters, which are spontaneously formed on the ScN film before the nanowire growth.

magnified image

SEM images of the ScAlN nanowires.
Chinese hamster ovary cell viability on hydrogen and oxygen terminated nano‐ and microcrystalline diamond surfaces
Authors: Smisdom Nick , Smets Ilse , Williams Oliver A. , Daenen Michaël , Wenmackers Sylvia , Haenen Ken , Nesládek Miloš , D'Haen Jan , Wagner Patrick , Rigo Jean‐Michel , Ameloot Marcel , vandeVen Martin
Published: August 2009

Transfected Chinese hamster ovary cells were cultured on bare uncoated chemical vapor deposited thin nano‐ and microcrystalline diamond surfaces, hydrophobic hydrogen‐ and hydrophilic oxygen‐terminated. Optical and biochemical analyses show that compared to glass controls, growth and viability were not significantly affected (one‐way‐analysis of variance, ANOVA). Based on two‐way ANOVA analyses, neither grain size nor surface termination had a significant influence until 5 days post‐seeding.
Ab initio prediction of half‐metallic ferromagnetic metamaterials composed of alkali metals with nitrogen
Authors: Zberecki Krzysztof , Adamowicz Leszek , Wierzbicki Michał
Published: August 2009

The first‐principles full‐potential linearized augmented plane‐wave method based on density functional theory is used to investigate electronic structure and magnetic properties of IA subgroup elements with nitrogen (LiN, NaN, KN, and RbN) in assumed three types of crystalline structure (rock salt, wurtzite, and zinc‐blende). We find that, due to the spin polarized p orbitals of N, all four compounds are half‐metallic ferromagnets with wide energy bandgaps (up to 2.0 eV). The calculated total magnetic moment in all investigated compounds for all three types of crystal structure is exactly 2.00 µB per formula unit. The predicted half‐metallicity is robust with respect to lattice‐constant contraction. In all the cases ferromagnetic phase is energetically favored with respect to the paramagnetic one. These theoretical results extend the range of materials which are potential candidates for synthesizing new magnetic systems needed in spin electronics.
Mass spectrometric study of N‐glycans from serum of woodchucks with liver cancer
Authors: Lattová Erika , McKenzie Eilean J. , Gruwel Marco L. H. , Spicer Vic , Goldman Radoslav , Perreault Hélène
Published: August 2009

Woodchucks have been a preferred lab animal model of chronic hepatitis B viral infection. The model recapitulates the disease progression of HBV infection to hepatocellular carcinoma (HCC) and has documented similarities in protein glycosylation with human HCC. This study examined N‐glycans in serum of animals with(out) HCC. Oligosaccharides were released enzymatically using PNGaseF from total serum or from serum partially fractionated by extraction. Two different extraction procedures – reversed‐phase high‐performance liquid chromatography (RP‐HPLC) and solid‐phase extraction (SPE) on a cation‐exchange/reversed‐phase STRATA‐XC cartridge – were used with the purpose of confirming glycosylation profiles. Oligosaccharides were analyzed by matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) after derivatization with phenylhydrazine and/or permethylation. Characteristic fragment ions produced under MS/MS conditions allowed discrimination between isomeric structures of oligosaccharides, including those sialylated with two types of acidic residues. The complementary methods allowed structural characterization of oligosaccharides from various N‐glycan classes. Furthermore, to validate results, glycosylation profiles of woodchuck sera were compared to glycans obtained from mouse serum on the same conditions. In summary, we have identified 40 N‐glycan structures in the serum of woodchucks and some types of oligosaccharide structures appeared to increase in HCC samples following protease digest. The study provides improved tools for the characterization of N‐glycans from total serum in the progression of liver disease. Copyright © 2009 John Wiley & Sons, Ltd.
Systematic analysis of posttranscriptional gene expression
Authors: Morris Adam R. , Mukherjee Neelanjan , Keene Jack D.
Published: August 2009

Recent systems studies of gene expression have begun to dissect the layers of regulation that underlie the eukaryotic transcriptome, the combined consequence of transcriptional and posttranscriptional events. Among the regulatory layers of the transcriptome are those of the ribonome, a highly dynamic environment of ribonucleoproteins in which RNA‐binding proteins (RBPs), noncoding regulatory RNAs (ncRNAs) and messenger RNAs (mRNAs) interact. While multiple mRNAs are coordinated together in groups within the ribonome of a eukaryotic cell, each individual type of mRNA consists of multiple copies, each of which has an opportunity to be a member of more than one modular group termed a posttranscriptional RNA operon or regulon (PTRO). The mRNAs associated with each PTRO encode functionally related proteins and are coordinated at the levels of RNA stability and translation by the actions of the specific RBPs and noncoding regulatory RNAs. This article examines the methods that led to the elucidation of PTROs and the coordinating mechanisms that appear to regulate the RNA components of PTROs. Moreover, the article considers the characteristics of the dynamic systems that drive PTROs and how mRNA components are bound collectively in physical ‘states’ to respond to cellular perturbations and diseases. In conclusion, these studies have challenged the extent to which cellular mRNA abundance can inform investigators of the functional status of a biological system. We argue that understanding the ribonome has greater potential for illuminating the underlying coordination principles of growth, differentiation, and disease. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Biological Mechanisms > Regulatory Biology
Characterization of chromosomal integration sites for heterologous gene expression in Saccharomyces cerevisiae
Authors: Bai Flagfeldt Dongmei , Siewers Verena , Huang Le , Nielsen Jens
Published: August 2009

The construction of mitotically stable yeast strains for heterologous gene or pathway expression often requires chromosomal integration. However, transcription levels vary between different chromosome regions. We therefore characterized 20 different integration sites of the Sacchromyces cerevisiae genome by inserting lacZ as a reporter gene under the control of two different promoters and determining expression levels through enzyme activity measurement. An up to 8.7‐fold difference was detected between the sites conferring lowest and highest expression, respectively. This opens the opportunity for modulating gene expression levels while retaining promoter and culture conditions. Copyright © 2009 John Wiley & Sons, Ltd.