bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cellular‐signaling pathways unveil the carcinogenic potential of chemicals
Authors: Hendriks Giel , van de Water Bob , Schoonen Willem , Vrieling Harry 
Published: January 2013

ABSTRACTMost 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

AbstractThe 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

AbstractLittle 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

AbstractThe 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

AbstractHemodialysis 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

AbstractBackbone 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. magnified image
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

AbstractFive 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

AbstractA 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.
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

AbstractNPM‐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

AbstractIn 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. magnified image
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

AbstractThe 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

AbstractThe 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

AbstractTetrapod (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

AbstractIn 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

AbstractWe 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

AbstractEffect 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

AbstractWe 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

AbstractDensity 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

AbstractGallium 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)