bluuebunny/crossref_metadata_2025 huggingface dataset:
A finite volume cell‐centered Lagrangian hydrodynamics approach for solids in general unstructured grids
Authors: Sambasivan Shiv Kumar , Shashkov Mikhail J , Burton Donald E
Published: January 2013

A finite volume cell‐centered Lagrangian hydrodynamics approach, formulated in Cartesian frame, is presented for solving elasto‐plastic response of solids in general unstructured grids. Because solid materials can sustain significant shear deformation, evolution equations for stress and strain fields are solved in addition to mass, momentum, and energy conservation laws. The total stress is split into deviatoric shear stress and dilatational components. The dilatational response of the material is modeled using the Mie‐Grüneisen equation of state. A predicted trial elastic deviatoric stress state is evolved assuming a pure elastic deformation in accordance with the hypo‐elastic stress‐strain relation. The evolution equations are advanced in time by constructing vertex velocity and corner traction force vectors using multi‐dimensional Riemann solutions erected at mesh vertices. Conservation of momentum and total energy along with the increase in entropy principle are invoked for computing these quantities at the vertices. Final state of deviatoric stress is effected via radial return algorithm based on the J‐2 von Mises yield condition. The scheme presented in this work is second‐order accurate both in space and time. The suitability of the scheme is evinced by solving one‐ and two‐dimensional benchmark problems both in structured grids and in unstructured grids with polygonal cells. Copyright © 2013 John Wiley & Sons, Ltd.
Synthesis and Self‐Assembly of Bolaamphiphiles Based on β‐Amino Acids or an Alcohol
Authors: Mainkar Prathama S. , Sridhar Chirumarry , Sudhakar Ambadi , Chandrasekhar Srivari
Published: January 2013

The synthesis of bolaamphiphiles from unusual β‐amino acids or an alcohol and C12 or C20 spacers is described. Unusual β‐amino acids such as a sugar amino acid, an AZT‐derived amino acid, a norbornene amino acid, and an AZT‐derived amino alcohol were coupled with spacers under standard conditions to get the novel bolaamphiphiles 5–8 (Scheme 1), 12 and 13 (Scheme 2), and 17 and 20 (Scheme 3). Some of these compounds, on precipitation from MeOH/H2O, self‐assembled into organized molecular structures.
Two New Sesquiterpenes from Euonymus alatus
Authors: Yan Zhao‐Hui , Han Zhu‐Zhen , Hu Xian‐Qing , Liu Qing‐Xin , Zhang Wei‐Dong , Liu Run‐Hui , Li Hui‐Liang
Published: January 2013

Two new sesquiterpenes, 1 and 2, as well as the five known compounds 3–7, were isolated from the stems of Euonymus alatus. Compounds 2–7 have a β‐dihydroagarofuran skeleton. The structures of these compounds were elucidated mainly by spectroscopic methods (1D‐, 2D‐NMR, ESI‐MS, and HR‐ESI‐MS). We also report the X‐ray crystal structure of evonine (3) for the first time.
Unexpected Approach to the Synthesis of 2‐Phenylquinoxalines and Pyrido[2,3‐b]pyrazines via a Regioselective Reaction
Authors: Alizadeh Abdolali , Mokhtari Javad
Published: January 2013

An unexpected approach to the preparation of quinoxaline and pyrido[2,3‐b]pyrazine derivatives 5 is described. The reaction between 1H‐indole‐2,3‐diones 1, 1‐phenyl‐2‐(triphenylphosphoranylidene)ethanone (2), and benzene‐1,2‐ or pyridine‐2,3‐diamines 3 proceeds in MeOH under reflux in good to excellent yields (Scheme 1 and Table). No co‐catalyst or activator is required for this multi‐component reaction (MCR), and the reaction is, from an experimental point of view, simple to perform. The structures of 5, 5′, and 6 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and were confirmed by comparison with reference compounds. A plausible mechanism for this type of reaction is proposed (Scheme 2).
Synthesis and Evaluation of Four Hederagenin Glycosides as α‐Glucosidase Inhibitor
Authors: Liu Qing‐Chao , Guo Tian‐Tian , Guo Shou‐Dong , Li Wen‐Hong , Li Dong
Published: January 2013

The four hederagenin glycosides 1–4 were efficiently synthesized through one‐pot sequential glycosylations with glycose 1‐(trichloroacetimidate)s as donors, resulting in a significantly simplified synthetic procedure without isolation of glycosylation intermediates. The activity of the synthetic hederagenin glycosides 1–4 against α‐glucosidase type IV was evaluated; hederagenin glycoside 4 containing an α‐L‐rhamnopyranosyl unit showed the best activity with an IC50 value of 47.9 μM.
Prenylated Benzene Metabolites from Melicope pteleifolia
Authors: Yang Li‐Jun , Jiang Kun , Tan Jun‐Jie , Qu Shi‐Jin , Luo Hong‐Feng , Tan Chang‐Heng , Zhu Da‐Yuan
Published: January 2013

Chemical investigation on the stem and root of Melicope pteleifolia afforded three new prenylated benzene metabolites as racemic mixtures, named pteleifolins A–C (1–3, resp.). Their gross structures were elucidated on the basis of spectroscopic analysis, especially 2D‐NMR experiments. An enantiomer resolution of (±)‐1 using chiral HPLC was performed, and the absolute configuration of the enantiomers were determined to be (+)‐(S)‐1 and (−)‐(R)‐1 by means of circular‐dichroism analysis.
Isoindolones from Lasiosphaera fenzliiReich. and Their Bioactivities
Authors: Lü Wen‐Wen , Gao Yun‐Jia , Su Ming‐Zhi , Luo Zhou , Zhang Wei , Shi Guo‐Bing , Zhao Qing‐Chun
Published: January 2013

Two new, 1 and 2, along with one known isoindolone, 3, were isolated from the AcOEt extract of Lasiosphaera fenzlii Reich. The structures of these compounds were determined as 4,6‐dihydroxy‐1H‐isoindole‐1,3(2H)‐dione (1), 4,6‐dihydroxy‐2,3‐dihydro‐1H‐isoindol‐1‐one (2), and clitocybin A (3) on the basis of chemical and spectroscopic evidences. The bioactivity assays revealed that all of them were devoid of significant cytotoxicities against tumor cells, whereas 1 exhibited potent antiangiogenic activity by inhibiting the secretion of vascular endothelial growth factor (VEGF) in A549 cells.
Folic acid supplementation and cancer risk: A meta‐analysis of randomized controlled trials
Authors: Qin Xianhui , Cui Yimin , Shen Lin , Sun Ningling , Zhang Yan , Li Jianping , Xu Xin , Wang Binyan , Xu Xiping , Huo Yong , Wang Xiaobin
Published: January 2013

There are growing data and a continuing controversy over the effect of folic acid supplementation on cancer risk. We conducted a meta‐analysis based on up‐to‐date published relevant randomized trials to further examine this issue. Relative risk (RR) was used to measure the effect of folic acid supplementation on risk of cancer using a random‐effects model. Overall, folic acid supplementation had no significant effect on total cancer incidence (13 trials, n = 49,406, RR = 1.05; 95% CI: 0.99–1.11, p = 0.13), colorectal cancer (seven trials, n = 33,824, 1.01; 0.82–1.23, p = 0.95), other gastrointestinal cancer (two trials, n = 20,228, 1.00; 0.75–1.33, p = 0.99), prostate cancer (five trials, n = 27,065, 1.17; 0.84–1.62, p = 0.35), other genitourinary cancer (two trials, n = 20,228, 0.97; 0.75–1.27, p = 0.84), lung cancer (five trials, n = 31,864, 1.00; 0.84–1.21, p = 0.97), breast cancer (four trials, n = 19,800, 0.82; 0.63–1.07, p = 0.15), hematological malignancy (three trials, n = 25,670, 0.87; 0.64–1.17, p = 0.35) and total cancer mortality (six trials, n = 31,930, 1.02; 0.90–1.15, p = 0.81). However, a significantly reduced risk was observed for melanoma (three trials, n = 19,128, 0.47; 0.23–0.94, p = 0.03). Furthermore, higher total cancer incidence risk was observed among those trials with a higher percent use of lipid‐lowering drugs (>60%, 1.10; 1.00–1.20, p = 0.04), or with lower percent baseline hypertension (≤70%, 1.08; 1.00–1.16, p = 0.057).Consistently, meta‐regression analyses suggested that the similar trend between percent use of lipid‐lowering drugs (p = 0.084) or percent baseline hypertension (p = 0.056) and log‐RR for total cancer incidence associated with folic acid supplementation. Our findings indicate that folic acid supplementation has no significant effect on total cancer incidence, colorectal cancer, prostate cancer, lung cancer, breast cancer or hematological malignancy, but reduces the risk of melanoma.
Exploring the association between genetic variation in the SUMO isopeptidase gene USPL1 and breast cancer through integration of data from the population‐based GENICA study and external genetic databases
Authors: Bermejo Justo Lorenzo , Kabisch Maria , Dünnebier Thomas , Schnaidt Sven , Melchior Frauke , Fischer Hans‐Peter , Harth Volker , Rabstein Sylvia , Pesch Beate , Brüning Thomas , Justenhoven Christina , Brauch Hiltrud , Baisch Christian , Ko Yon‐Dschun , Hamann Ute
Published: January 2013

Small ubiquitin‐like modifier (SUMO) proteins are covalently attached to target proteins to modify their function. SUMO conjugation participates in processes tightly linked to tumorigenesis. Recently USPL1 (ubiquitin‐specific peptidase‐like (1) was identified as a SUMO isopeptidase. We report here on the first exploratory study investigating the relationship between genetic variability in USPL1 and breast cancer. Three potentially functional nonsynonymous coding SNPs (rs3742303, rs17609459, rs7984952) were genotyped in 1,021 breast cancer cases and 1,015 controls from the population‐based GENICA study. We took advantage of multiple genotype imputation based on HapMap and the 1000 Genomes Project data to refine the association screening in the investigated region. Public genetic databases were also used to investigate the relationship with USPL1 expression in lymphoblastoid cell lines and breast tissue. Women homozygous for the minor C allele of rs7984952 showed a lower risk of Grade 3 breast tumors compared to TT homozygotes (OR 0.50, 95% CI 0.30‐0.81). Case‐only analyses confirmed the association between rs7984952 and tumor grade (OR 0.60, 95% CI 0.39‐0.93). Imputation results in a 238 kb region around rs7984952 based on HapMap and the 1000 Genomes Project data were similar. No imputed variant showed an association signal stronger than rs7984952. USPL1 expression in tumor breast tissue increased with the number of C alleles. The present study illustrates the contribution of multiple imputation of genotypes using public data repositories to standard genotyping laboratory. The provided information may facilitate the design of independent studies to validate the association between USPL1 rs7984952 and risk of Grade 3 breast tumors.
Operation mechanism of FoF1‐adenosine triphosphate synthase revealed by its structure and dynamics
Authors: Iino Ryota , Noji Hiroyuki
Published: January 2013

FoF1‐Adenosine triphosphate (ATP) synthase, a complex of two rotary motor proteins, reversibly converts the electrochemical potential of protons across the cell membrane into phosphate transfer potential of ATP to provide the energy currency of the cell. The water‐soluble motor is F1‐ATPase, which possesses ATP synthesis/hydrolysis catalytic sites. Isolated F1 hydrolyses ATP to rotate the rotary shaft against the stator ring. The membrane‐embedded motor is Fo, which is driven by proton flow down the proton electrochemical potential. In the FoF1 complex, the direction of mechanical rotation, the chemical reaction, and the proton transport are determined by the relative amplitudes between the Gibbs free energy of the ATP hydrolysis reaction and the electrochemical potential of protons across the membrane. Therefore, FoF1‐ATP synthase is a highly efficient molecular device in which the chemical, mechanical, and potential energies are tightly and reversibly converted. In this critical review, we summarize our latest knowledge about the operation mechanism of this sophisticated nanomachine, revealed by its structure and dynamics. © 2013 IUBMB Life, 65(3):238–246, 2013.
What is the nature of the mitochondrial permeability transition pore and What is it Not?
Authors: Siemen Detlef , Ziemer Mirjam
Published: January 2013

Since about 60 years a phenomenon now called permeability transition is known in mitochondria. It involves a large pore in the inner mitochondrial membrane, the permeability transition pore (PTP) whose molecular structure is still unknown. Year after year, new hypotheses have been developed how this pore could look like and which proteins cold be structural elements. Enormous progress was made in understanding function, rich pharmacology, and possible biochemical modulation of the PTP. However, many of the structural hypotheses that seemed to be well established by experiments had to be rejected later after their falsification by further experiments. The aim of this review is to give a brief insight into confirmed and less known details of the nature of the pore and of its function. Thereafter, this review will critically report about some of the unknown elements and hypotheses that had to be rejected. © 2013 IUBMB Life, 65(3):255–262, 2013.
Cellular‐signaling pathways unveil the carcinogenic potential of chemicals
Authors: Hendriks Giel , van de Water Bob , Schoonen Willem , Vrieling Harry
Published: January 2013

Most of the current in vitro carcinogenicity assays assess the potential carcinogenic properties of chemicals through the detection of inflicted DNA damage or subsequent chromosome damage and gene mutations. Unfortunately, these assays generally do not provide mechanistic insight into the reactive properties of a chemical. Upon chemical‐induced damage of biomolecules, molecular sensors will activate general and damage‐specific cellular response pathways that provide protection against the (geno)toxic and potential carcinogenic properties of chemicals. These cellular defense mechanisms include activation of cell‐cycle checkpoints, DNA repair systems and induction of apoptosis or necrosis. Visualization of activated cellular‐signaling pathways forms a powerful means to readily detect the genotoxic potential of chemical compounds and simultaneously gain insight into their reactive properties. Over the past years, various in vitro reporter assays have been developed that monitor activation of general and more specific cellular‐signaling pathways, including the GreenScreen HC and ToxTracker assays. In this review we provide a perspective on how we can exploit activation of cellular signaling pathways to shed light on the mode of action of the chemical exposure and to develop sophisticated mechanism‐based in vitro assays for cancer risk assessment. Copyright © 2013 John Wiley & Sons, Ltd.
Enhancement of extracellular molecule uptake in plasmonic laser perforation
Authors: Kalies Stefan , Birr Tobias , Heinemann Dag , Schomaker Markus , Ripken Tammo , Heisterkamp Alexander , Meyer Heiko
Published: January 2013

The use of laser induced surface plasmons on metal nanoparticles has proven to be an excellent tool for the delivery of molecules like siRNA and DNA into cells. However, a detailed understanding of the basic mechanisms of molecular uptake and the influence of parameters like biological environment is missing. In this study we analyzed the uptake of fluorescent dextrans with sizes from 10 to 2000 kDa, which resembles a wide range of biologically relevant molecules in size using a 532 nm picosecond laser system and 200 nm gold nanoparticles. Our results show a strong uptake‐dependence on cell medium or buffer, but no dominant dependence on osmotic conditions. The relation between pulse energy and number of pulses for a given perforation efficiency revealed that multiphoton ionization of water might contribute to perforation. Moreover, a seven‐fold uptake‐enhancement could be reached with optimized parameters, providing a very promising basis for further studies and applications. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homicide Detectives' Intuition
Authors: Wright Michelle
Published: January 2013

Little is known about the decision‐making processes of homicide detectives; this study is a first step towards understanding the inferential processes they engage in during the initial stages of an investigation. A card sorting exercise consisting of 20 crime scene photographs showing homicide victims in situ was designed to examine how detectives categorise and conceptualise homicide crime scenes. Forty homicide detectives were asked to ‘think aloud’ whilst categorising the crime scenes. Qualitative content analysis of the ‘think aloud’ accounts revealed detectives' intuitive ability to automatically make detailed inferences regarding the circumstances surrounding each homicide on the basis of available crime scene information (victim's sex, location, and method of death). A cycle of cognition was evident whereby detectives drew upon the contextual information available to generate hypotheses regarding homicide type (domestic, male brawl, and crime‐related) and derive inferences about victim–offender relationship, offender behaviour, motive, and whether the offence was spontaneous or planned. The detectives made 594 inferences of which 67% (N = 398) were accurate. The sorting exercise proved to be ecologically valid, with detectives reporting that they assessed and interpreted the homicide crime scenes, as they would in an actual investigation. The implications for police training and ‘offender profiling’ research are discussed. Copyright © 2013 John Wiley & Sons, Ltd.
Decisions To Be Taken in the Use of Polygraph Examinations for Verifying Complaints About Violence: Analysis and Policy Recommendations
Authors: Ginton Avital
Published: January 2013

The paper introduces the basic logic and assumptions underlying the most widespread polygraph technique, the Comparison Question Test. It then indicates that two of these assumptions encounter difficulties in cases involving victims of violence, which could increase the danger of error on the test. To handle this problem, it is required to take a few decisions related to specific professional procedures as well as to implement a special policy. Another line of problems stems from ethical considerations. The main point in this respect is that being polygraphed is quite an unpleasant experience. This is more so when the examinee is an authentic victim of violence whose complaint is under investigation. Polygraphing such a person adds to the suffering of the victim. The ethical question becomes a practical one, namely how to determine the situations in which polygraph examination on an alleged victim is, nevertheless, justifiable and differentiate them from other situations. A conceptual cost–benefit analysis is presented in this regard, and the need for taking specific decisions by the polygraph examiner, the criminal investigator, and the commanding officer, when facing the option of using the polygraph for investigating complaints about violence, is pointed out, together with a recommended policy. Copyright © 2013 John Wiley & Sons, Ltd.
Prevalence and risk factors of hepatitis C and B virus infections in hemodialysis patients and their spouses: A multicenter study in Beijing, China
Authors: Su Yingying , Yan Ruixue , Duan Zhongping , Norris Jessie L. , Wang Lu , Jiang Yan , Xing Wenge , Chen Yu , Xiao Yao , Li Lu , Tao Jun , Wang Ning
Published: January 2013

Hemodialysis patients are at risk for hepatitis C and B virus infections. This study investigated the prevalences and risk factors of HCV and HBV infection and the distribution of HCV genotypes among hemodialysis patients and their spouses. From August to November 2011, a cross‐sectional study was conducted on 20 hemodialysis units in Beijing to investigate prevalences and risk factors for markers of HCV and HBV among 2,120 patients and 409 spouses. In hemodialysis patients, prevalences of anti‐HCV, HCV RNA, and hepatitis B surface antigen (HBsAg) were 6.1%, 4.6%, and 7.0%, respectively. The prevalence of HCV antibodies among spouses was 0.5%, of HCV RNA was 0.2%, and of HBsAg was 4.2%. Risk factors for HCV infection were dialysis duration, blood transfusion, and attending more than one dialysis unit. HBV infection was independently associated with age, family member with hepatitis infection, gender, and surgery. The predominant HCV genotypes were 1b (89.0%) and 2a (7.7%), and genotypes 3a, 3b, and 6a were each 1.1%. A significant decrease in HCV and HBV prevalences in Chinese dialysis units showed that infection control measures were effective. However, because nosocomial transmissions persist, strict adherence to infection control measures should be emphasized to reduce the risk of transmission. J. Med. Virol. 85:425–432, 2013. © 2013 Wiley Periodicals, Inc.
Synthesis of Long‐Circulating, Backbone Degradable HPMA Copolymer–Doxorubicin Conjugates and Evaluation of Molecular‐Weight‐Dependent Antitumor Efficacy
Authors: Pan Huaizhong , Sima Monika , Yang Jiyuan , Kopeček Jindřich
Published: January 2013

Backbone degradable, linear, multiblock N‐(2‐hydroxypropyl)methacrylamide (HPMA) copolymer–doxorubicin (DOX) conjugates are synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization followed by chain extension via thiol‐ene click reaction. The examination of molecular‐weight‐dependent antitumor activity toward human ovarian A2780/AD carcinoma in nude mice reveals enhanced activity of multiblock, second‐generation, higher molecular weight conjugates when compared with traditional HPMA copolymer–DOX conjugates. The examination of body weight changes during treatment indicates the absence of non‐specific adverse effects.

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Precise Synthesis of New Triblock Co‐ and Terpolymers by a Methodology Combining Living Anionic Polymers with a Specially Designed Linking Reaction
Authors: Matsuo Yuri , Oie Toshiyuki , Goseki Raita , Ishizone Takashi , Sugiyama Kenji , Hirao Akira
Published: January 2013

Five A‐B‐A′, A‐C‐A′, B‐A‐B′, C‐A‐C′, and C‐B‐C′ triblock terpolymers with block orders difficult to synthesize by sequential polymerization have been successfully synthesized by a new methodology combining living anionic polymers with a specially designed linking reaction using α‐phenylacrylate as the reaction site. Here, A(A′), B(B′), and C(C′) represent groups of polymers (having chain‐end anions with different nucleophilicities), which are only polymerizable from A(A′) to B(B′) to C(C′) via sequential polymerization. The corresponding polymers are polystyrene (A) and poly(α‐methylstyrene) (A′), poly(2‐vinylpyridine) (B) and poly(4‐vinylpyridine) (B′) and polymers from methacrylate type monomers like poly(methyl methacrylate) (C), poly(tert‐butyl methacrylate) (C′), poly(2‐hydroxyethyl methacrylate) (C′), poly(2,3‐dihydroxypropyl methacrylate) (C′), and poly(ferrocenylmethyl methacrylate) (C′). Furthermore, three synthetically difficult B‐A‐B, C‐A‐C, and C‐B‐C triblock copolymers with molecular asymmetry in both side blocks have also been synthesized by the developed methodology. All of the polymers thus synthesized are quite new triblock terpolymers and copolymers with well‐defined structures, i.e., precisely controlled molecular weights, compositions and narrow molecular weight distributions (Mw/Mn ≤ 1.05).
In Situ Direct Mechanistic Transformation from FeCl3‐Catalyzed Living Cationic to Radical Polymerizations
Authors: Aoshima Hiroshi , Satoh Kotaro , Kamigaito Masami
Published: January 2013

A trivalent iron chloride (FeCl3) catalyst induced both living cationic and radical polymerizations of various monomers in the presence of an appropriate additive or ligand to yield polymers with controlled molecular weights and narrow molecular‐weight distributions. The in‐situ mechanistic transformation from a living cationic to a radical growing species during the styrene polymerization was achieved in a FeCl3‐based system with the simple addition of phosphine followed by an elevation of the reaction temperature. The growing cationic species was effectively converted into the radical species to produce a series of block copolymers that consist of styrene and various acrylic monomers.
Financial Crisis and Changes in Firm Governance, Corporate Structure, and Boundaries
Authors: Polat Rena , Nisar Tahir M.
Published: January 2013

The paper researches the effects of the 2008 financial crisis on various measures of firm governance, including the impact on firm boundaries such as buyer–supplier relationship, capital structure, and employment effects. Using a unique data set of 1686 Eastern European firms, we examine how the crisis affected the financial and employment decisions of different industrial and service sector firms. As these firms faced a steep decline in sales and capacity utilization, as well as credit constrains, they were forced to make significant and far reaching changes in various aspects of their operations. We discuss the implications of these changes. Copyright © 2013 John Wiley & Sons, Ltd.
N‐N migration of a carbamoyl group in a pyrazole derivative revealed by NMR
Authors: Pathirana Charles , Sfouggatakis Chris , Palaniswamy Venkatapuram
Published: January 2013

During a synthesis of 5‐amino‐4‐(6‐methoxy‐2‐methylpyridin‐3‐yl)‐3‐methyl‐1H‐pyrazole‐1‐carboxamide (see Scheme 1), a side‐reaction produced 3‐amino‐4‐(6‐methoxy‐2‐methylpyridin‐3‐yl)‐5‐methyl‐1H‐pyrazole‐1‐carboxamide as a by‐product that forms an equilibrium with the target‐compound. The structure of the by‐product was elucidated by the interpretation of 1D and 2D (HMQC, HMBC) NMR data where 1H‐15 N HMBC correlations revealed the position of carbamoyl group attachment on the pyrazole. Comparison of structures of the target‐compound and the by‐product showed that the latter resulted from N‐N migration of the carbamoyl group in the target‐compound. Copyright © 2013 John Wiley & Sons, Ltd.
Synergistic effects of 4A zeolite on the flame retardant properties and thermal stability of a novel halogen‐free PP/IFR composite
Authors: Feng Caimin , Zhang Yi , Liu Siwei , Chi Zhenguo , Xu Jiarui
Published: January 2013

The synergistic effects of 4A zeolite (4A) on the thermal degradation, flame retardancy and char formation of a novel halogen‐free intumescent flame retardant polypropylene composites (PP/IFR) were investigated by the means of limiting oxygen index (LOI), vertical burning test (UL‐94), digital photos, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), cone calorimeter test (CCT), laser Raman spectroscopy (LRS) and X‐ray photoelectron spectroscopy (XPS). It was found that a small amount of 4A could dramatically enhance the LOI value of the PP/IFR systems and the materials could pass the UL‐94 V‐0 rating test. Also, it could enhance the fire retardant performance with a great reduction in combustion parameters of PP/IFR system from CCT test. The morphological structures observed by digital and SEM photos revealed that 4A could promote PP/IFR to form more continuous and compact intumescent char layer. The LRS measurement, XPS and TGA analysis demonstrated that the compactness and strength of the outer char surface of the PP/IFR/4A system was enhanced, and more graphite structure was formed to remain more char residue and increase the crosslinking degree. Copyright © 2013 John Wiley & Sons, Ltd.
NPM‐ALK up‐regulates iNOS expression through a STAT3/microRNA‐26a‐dependent mechanism
Authors: Zhu Haifeng , Vishwamitra Deeksha , Curry Choladda V , Manshouri Roxsan , Diao Lixia , Khan Aarish , Amin Hesham M
Published: January 2013

NPM‐ALK chimeric oncogene is aberrantly expressed in an aggressive subset of T‐cell lymphomas that frequently occurs in children and young adults. The mechanisms underlying the oncogenic effects of NPM‐ALK are not completely elucidated. Inducible nitric oxide synthase (iNOS) promotes the survival and maintains the malignant phenotype of cancer cells by generating NO, a highly active free radical. We tested the hypothesis that iNOS is deregulated in NPM‐ALK+ T‐cell lymphoma and promotes the survival of this lymphoma. In line with this possibility, an iNOS inhibitor and NO scavenger decreased the viability, adhesion, and migration of NPM‐ALK+ T‐cell lymphoma cells, and an NO donor reversed these effects. Moreover, the NO donor salvaged the viability of lymphoma cells treated with ALK inhibitors. In further support of an important role of iNOS, we found iNOS protein to be highly expressed in NPM‐ALK+ T‐cell lymphoma cell lines and in 79% of primary tumours but not in human T lymphocytes. Although expression of iNOS mRNA was identified in NPM‐ALK+ T‐cell lymphoma cell lines and tumours, iNOS mRNA was remarkably elevated in T lymphocytes, suggesting post‐transcriptional regulation. Consistently, we found that miR‐26a contains potential binding sites and interacts with the 3'‐UTR of iNOS. In addition, miR‐26a was significantly decreased in NPM‐ALK+ T‐cell lymphoma cell lines and tumours compared with T lymphocytes and reactive lymph nodes. Restoration of miR‐26a in lymphoma cells abrogated iNOS protein expression and decreased NO production and cell viability, adhesion, and migration. Importantly, the effects of miR‐26a were substantially attenuated when the NO donor was simultaneously used to treat lymphoma cells. Our investigation of the mechanisms underlying the decrease in miR‐26a in this lymphoma revealed novel evidence that STAT3, a major downstream substrate of NPM‐ALK tyrosine kinase activity, suppresses MIR26A1 gene expression. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Some Remarks on Chemical Derivatization of Polymer Surfaces after Exposure to Nitrogen‐Containing Plasmas
Authors: Klages Claus‐Peter , Khosravi Zohreh , Hinze Alena
Published: January 2013

In this paper some basic assumptions underlying the chemical derivatization analysis of polymer surfaces treated in nitrogen‐containing plasmas are critically examined. Imines, which are known to represent major constituents of such surfaces as well as of plasma polymers grown from amine precursors, show a very versatile chemical reactivity. For example, imines are generally able to exchange their carbonyl component with aromatic aldehydes. Therefore, surface reactivity of polymers treated in nitrogen‐containing plasmas with 4‐trifluoromethyl‐benzaldehyde (TFBA) or other benzaldehydes appears to be attributable not only to (primary) amines. Similar conclusions must be drawn for several other derivatization reagents.

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Open and shut: Crystal structures of the dodecylmaltoside solubilized mechanosensitive channel of small conductance from Escherichia coli and Helicobacter pylori at 4.4 Å and 4.1 Å resolutions
Authors: Lai Jeffrey Y. , Poon Yan Shuen , Kaiser Jens T. , Rees Douglas C.
Published: January 2013

The mechanosensitive channel of small conductance (MscS) contributes to the survival of bacteria during osmotic downshock by transiently opening large diameter pores for the efflux of cellular contents before the membrane ruptures. Two crystal structures of the Escherichia coli MscS are currently available, the wild type protein in a nonconducting state at 3.7 Å resolution (Bass et al., Science 2002; 298:1582–1587) and the Ala106Val variant in an open state at 3.45 Å resolution (Wang et al., Science 2008; 321:1179–1183). Both structures used protein solubilized in the detergent fos‐choline‐14. We report here crystal structures of MscS from E. coli and Helicobacter pylori solubilized in the detergent β‐dodecylmaltoside at resolutions of 4.4 and 4.2 Å, respectively. While the cytoplasmic domains are unchanged in these structures, distinct conformations of the transmembrane domains are observed. Intriguingly, β‐dodecylmaltoside solubilized wild type E. coli MscS adopts the open state structure of A106V E. coli MscS, while H. pylori MscS resembles the nonconducting state structure observed for fos‐choline‐14 solubilized E. coli MscS. These results highlight the sensitivity of membrane protein conformational equilibria to variations in detergent, crystallization conditions, and protein sequence.
Rapid expression screening of eukaryotic membrane proteins in Pichia pastoris
Authors: Brooks Cory L. , Morrison Melissa , Joanne Lemieux M.
Published: January 2013

The overexpression of milligram quantities of protein remains a key bottleneck in membrane protein structural biology. A challenge of particular difficulty has been the overproduction of eukaryotic membrane proteins. In order to cope with the frequently poor expression levels associated with these challenging proteins, it is often necessary to screen a large number of homologues to find a well expressing clone. To facilitate this process using the heterologous, eukaryotic expression host Pichia pastoris, we have developed a simple fluorescent induction plate‐screening assay that allows for the rapid detection of well expressing clones of eukaryotic membrane proteins that have been fused to GFP. Using a eukaryotic membrane protein known to express well in P. pastoris (human aquaporin 4) and homologues of the ER associated membrane protein phosphatidylethanolamine N‐methyltransferase (PEMT), we demonstrate that when a large number of clones are screened, a small number of highly expressing “jackpot” clones can be isolated. A jackpot PEMT clone resulted in 5 mg/L yield after purification. The method allows for the facile simultaneous screening of hundreds of clones providing an alternate to in‐culture screening and will greatly accelerate the search for overexpressing eukaryotic membrane proteins.
Enhanced performance of organic photovoltaic devices by incorporation of tetrapod‐shaped CdSe nanocrystals in polymer–fullerene systems
Authors: Ahmad Razi , Arora Vikas , Srivastava Ritu , Sapra Sameer , Kamalasanan Modeeparampil N.
Published: January 2013

Tetrapod (TP)‐shaped colloidal CdSe nanocrystals (NCs) were synthesized by a hot injection method in inert atmosphere using standard Schlenk line techniques and characterized by UV–Vis absorption, photoluminescence (PL), X‐ray diffraction (XRD), and transmission electron microscopy. NCs with an average diameter of 4 nm and an average length of 23 nm have been obtained with a wurtzite crystal structure. Hybrid organic photovoltaic (OPV) devices were fabricated from ternary blends of poly(3‐hexylthiophene‐2,5‐diyl):[6,6]‐phenyl C71butyric acid methyl ester (P3HT:PC71BM) and TP‐shaped CdSe NCs at 0–2 wt.% concentration range. The hybrid OPV devices with CdSe NCs at an optimum concentration of 1.5 wt.% exhibited higher short‐circuit current density (JSC) and power conversion efficiency (PCE) than the devices without NCs. This improvement has been attributed to enhanced electron transport through the TPs in the direction perpendicular to the plane of substrate.
Electron spin resonance of paramagnetic defects and related charge carrier traps in complex oxide scintillators
Authors: Laguta V. V. , Nikl M.
Published: January 2013

In the family of application‐important complex, oxide single crystal scintillators based on tungstates, aluminum perovskites, and yttrium (lutetium) orthosilicates, selected results of electron spin resonance study are presented. They are focused on various point defects, which participate in the processes of charge carriers transfer and capture. Particular attention is paid to the most natural defects inevitably present in oxide materials such as anion and cation vacancies, antisite defects, self‐trapped electron, and hole states. Current understanding of the nature of such charge trapping states and mechanisms of their creation in the selected oxide scintillation materials are discussed as well.
GaInNAs/GaAs MQW pin photodetector for the 1.3 μm optical communications window
Authors: Khalil Hagir Mohammed , Mazzucato Simone , Balkan Naci
Published: January 2013

We present the temporal response characteristic of a dilute nitride based (GaInNAs/GaAs) p‐i‐n multiple quantum well (MQW) device for operation as fast photodetector in the 885 to 1127 nm wavelength region. The temperature dependence of the transient photoconductivity (TPC) at different bias voltages and excitation intensity are reported. We measured the PC rise and fall times by the use of a 1064 nm pulsed Nd‐YAG laser as the excitation source. The pulsewidth is 100 ps and the repetition rate 5 Hz. The TPC rise time was of about 2 ns at T=100 K, increasing to 4 ns at room temperature. The PC decay curve had two time constants, with a fast decay time of 5 ns, followed by a slower component of about 200 ns at T=300 K (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of thermal annealing on defects in post‐growth hydrogenated GaNP
Authors: Dagnelund D. , Tu C. W. , Polimeni A. , Capizzi M. , Chen W. M. , Buyanova I. A.
Published: January 2013

Effect of thermal annealing on paramagnetic centers in post‐growth hydrogenated GaN0.0081P0.9919 epilayer is examined by means of photoluminescence and optically detected magnetic resonance (ODMR) techniques. In recent studies, several Ga‐interstitial (Gai) related centers were found to be activated by the presence of hydrogen in the hydrogenated GaNP alloys. These centers compete with near‐band edge radiative recombination. Annealing at 400 ºC in Ar‐ambient is found to cause quenching of the Gai‐related ODMR signals that were activated by post‐growth hydrogenation. We tentatively ascribe this effect to dissociation of the H‐Gai complexes and subsequent out‐diffusion of H. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Plasma‐assisted electroepitaxy of GaN layers
Authors: Novikov S. V. , Foxon C. T.
Published: January 2013

We have studied the growth of GaN layers by plasma‐assisted electroepitaxy (PAEE). We have used an RF‐plasma source to produce high concentrations of N species in the Ga melt and a high DC electric current to transfer the N species from the Ga surface to the growth interface. We have achieved continuous GaN layers by PAEE at growth temperatures as low as ∼650oC. We have also investigated PAEE growth of GaN layers on GaN nanocolumn templates. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DFT modeling of AlN/GaN multi‐quantum wells
Authors: Strak Pawel , Kempisty Pawel , Ptasinska Maria , Krukowski Stanislaw
Published: January 2013

Density functional theory simulations have been used to obtain physical properties of AlN/GaN multi‐quantum well (MQW) system characterized by equal width of wells and barriers. Such structure could have different thickness that affects their optical and electronic properties. For thickness up to 4 metal atomic layers, GaN region behaves as potential local minimum while for larger thickness it is a standard quantum well. Separation of an electron and hole wavefunction affects negatively radiative transition probabilities. Reduction of optical efficiency for systems with different structure width was determined by calculation of oscillator strength values. Field intensities along c‐direction and the change of the energy of the optical transitions, due to quantum confined Stark effect (QCSE), were also obtained. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of zinc concentration in GaN:Zn,Si from photoluminescence
Authors: Mohajerani Matin Sadat , Reshchikov Michael A. , Behrends Arne , Bakin Andrey , Kück Stefan , Waag Andreas
Published: January 2013

Gallium nitride samples codoped with zinc and silicon were fabricated by metal organic chemical vapor deposition. Optical properties of these samples with lowlevel doped acceptor are investigated by temperature dependent photoluminescence (PL) measurements. PL spectrum shows three peaks labeled as near band edge (NBE), blue luminescence (BL), and yellow luminescence (YL).

BL originates from ZnGa acceptors in GaN:Zn,Si. It is quenched above 250 K for all samples measured at excitation density of Pexc = 0.2 Wcm−2. The concentration of acceptors responsible for the BL band is estimated for relatively low Zn concentrations by comparing integrated PL intensity of NBE and Zn‐related BL bands at 200 K (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nitride‐based hetero‐field‐effect‐transistor‐type photosensors with extremely high photosensitivity
Authors: Ishiguro Mami , Ikeda Kazuya , Mizuno Masataka , Iwaya Motoaki , Takeuchi Tetsuya , Kamiyama Satoshi , Akasaki Isamu
Published: January 2013

AlGaN/GaN hetero‐field‐effect‐transistor‐type (HFET‐type) photosensors are fabricated with a p‐GaInN optical gate for the detection of visible light. These photosensors employ a two‐dimensional electron gas at the heterointerface between AlGaN and GaN as a highly conductive channel with a high electron mobility. By changing the InN molar fraction in the p‐GaInN optical gate, the wavelength range of the photosensitivity of the HFET‐type photosensors can be controlled. The photosensitivity of the AlGaN/GaN HFET‐type photosensors with a p‐GaInN optical gate greatly surpassed those of commercially available Si pin and Si avalanche photodiodes, and was comparable to those of photomultiplier tubes. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A method to diagnose boundary‐layer type using Doppler lidar
Authors: Harvey Natalie J. , Hogan Robin J. , Dacre Helen F.
Published: January 2013

A new technique for objective classification of boundary layers is applied to ground‐based vertically pointing Doppler lidar and sonic anemometer data. The observed boundary layer has been classified into nine different types based on those in the Met Office ‘Lock’ scheme, using vertical velocity variance and skewness, along with attenuated backscatter coefficient and surface sensible heat flux. This new probabilistic method has been applied to three years of data from Chilbolton Observatory in southern England and a climatology of boundary‐layer type has been created. A clear diurnal cycle is present in all seasons. The most common boundary‐layer type is stable with no cloud (30.0% of the dataset). The most common unstable type is well mixed with no cloud (15.4%). Decoupled stratocumulus is the third most common boundary‐layer type (10.3%) and cumulus under stratocumulus occurs 1.0% of the time. The occurrence of stable boundary‐layer types is much higher in the winter than the summer and boundary‐layer types capped with cumulus cloud are more prevalent in the warm seasons. The most common diurnal evolution of boundary‐layer types, occurring on 52 days of our three‐year dataset, is that of no cloud with the stability changing from stable to unstable during daylight hours. These results are based on 16393 hours, 62.4% of the three‐year dataset, of diagnosed boundary‐layer type. This new method is ideally suited to long‐term evaluation of boundary‐layer type parametrisations in weather forecast and climate models.
Differences in birth weight by sex using adjusted quantile distance functions
Authors: Lehre Anne‐Catherine , Laake Petter , Sexton Joseph Andrew
Published: January 2013

Herein, we report results from a study of birth weight distribution among boys and girls born in Norway in 2008. As our primary interest was to detect differences in the variability between the two sexes, we used the quantile distance function to describe the difference between two distribution functions. We used an adjusted version of the quantile function to look into the relation of sex differences in birth weight conditioned on maternal age, gestational age, preeclampsia, maternal diabetes type 1, maternal smoking status, and parity. At term (⩾37 weeks of gestation), boys showed a greater variability in birth weight than did girls, and these differences were maintained in the adjusted model. We also found that maternal age and maternal smoking habits influenced both sexes equally, whereas gestational age, preeclampsia, maternal diabetes type 1, and parity influenced one sex more than the other. The adjusted quantile distance function proved efficient in analyzing and demonstrating how covariates influence sex differences in birth weight. Copyright © 2013 John Wiley & Sons, Ltd.
Scheduling component replacement for timely execution in dynamic systems
Authors: Romero Julio Cano , García‐Valls Marisol
Published: January 2013

Timely run‐time software replacement techniques are a corner stone for reconciling real‐time systems development and dynamic behavior. Typical real‐time systems do not consider dynamic behavior because it deeply challenges predictability and timeliness. Current efforts are starting to merge the safe and predictable execution with a controllable level of dynamicity by imposing a set of bounds and limitations to the system dynamic behavior. One of the obstacles for this is how to time‐bound the different operations required to effectively implement component replacement. In this paper, the main challenges for this problem are identified, and a model to ensure that components can be replaced at run time preserving the temporal properties of the system is provided that also avoids failures in replacements. A real example and simulations of our replacement model are provided that validate the presented ideas. Copyright © 2013 John Wiley & Sons, Ltd.
Programs as visual, interactive documents
Authors: French G.W. , Kennaway J.R. , Day A.M.
Published: January 2013

We present a novel approach to combined textual and visual programming by allowing visual, interactive objects to be embedded within textual source code and segments of source code to be further embedded within those objects. We retain the strengths of text‐based source code, while enabling visual programming where it is beneficial. Additionally, embedded objects and code provide a simple object‐oriented approach to adding a visual form of LISP‐style macros to a language. The ability to freely combine source code and visual, interactive objects with one another allows for the construction of interactive programming tools and experimentation with novel programming language extensions. Our visual programming system is supported by a type coercion‐based presentation protocol that displays normal Java and Python objects in a visual, interactive form. We have implemented our system within a prototype interactive programming environment called ‘The Larch Environment’. Copyright © 2013 John Wiley & Sons, Ltd.
Efficient Generation of Astrocytes from Human Pluripotent Stem Cells in Defined Conditions
Authors: Shaltouki Atossa , Peng Jun , Liu Qiuyue , Rao Mahendra S. , Zeng Xianmin
Published: January 2013

Astrocytes can be generated from various tissue sources including human pluripotent stem cells (PSC). In this manuscript, we describe a chemically defined xeno-free medium culture system for rapidly generating astrocytes from neural stem cells derived from PSC. We show that astrocyte development  in vitro, mimics normal development  in vivo, and also passes through a CD44+  astrocyte precursor stage. Astrocytes generated by our method display similar gene expression patterns, morphological characteristics and functional properties to primary astrocytes, and they survive and integrate after xenotransplantation. Whole genome expression profiling of astrocyte differentiation was performed at several time points of differentiation, and the results indicate the importance of known regulators and identify potential novel regulators and stage-specific lineage markers.