bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein conformation changes on block copolymer surfaces detected by antibody‐functionalized atomic force microscope tips
Authors: Palacio Manuel L. B. , Schricker Scott R. , Bhushan Bharat 
Published: October 2011

AbstractConformational changes of fibronectin (Fn) deposited on poly(methyl methacrylate) and poly(acrylic acid) block copolymers with identical chemical compositions were detected using an antibody‐functionalized atomic force microscope (AFM) tip. Based on the antibody‐protein adhesive force maps and phase imaging, it was found that the nanomorphology of the triblock copolymer is conducive to the exposure of the arginine‐glycine‐aspartic acid (RGD) groups in Fn. For the first time, X‐ray photoelectron spectroscopy was used to elucidate surface chemical composition and confirm AFM results. The findings demonstrate that block copolymer nanomorphology can be used to regulate protein conformation and potentially cellular response. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Chondrocyte redifferentiation in 3D: The effect of adhesion site density and substrate elasticity
Authors: Schuh Elena , Hofmann Sandra , Stok Kathryn , Notbohm Holger , Müller Ralph , Rotter Nicole 
Published: October 2011

AbstractTo obtain sufficient cell numbers for cartilage tissue engineering with autologous chondrocytes, cells are typically expanded in monolayer culture. As a result, they lose their chondrogenic phenotype in a process called dedifferentiation, which can be reversed upon transfer into a 3D environment. We hypothesize that the properties of this 3D environment, namely adhesion site density and substrate elasticity, would influence this redifferentiation process. To test this hypothesis, chondrocytes were expanded in monolayer and their phenotypical transition was monitored. Agarose hydrogels manipulated to give different RGD adhesion site densities and mechanical properties were produced, cells were incorporated into the gels to induce redifferentiation, and constructs were analyzed to determine cell number and extracellular matrix production after 2 weeks of 3D culture. The availability of adhesion sites within the gels inhibited cellular redifferentiation. Glycosaminoglycan production per cell was diminished by RGD in a dose‐dependent manner and cells incorporated into gels with the highest RGD density, remained positive for collagen type I and produced the least collagen type II. Substrate stiffness, in contrast, did not influence cellular redifferentiation, but softer gels contained higher cell numbers and ECM amounts after 2 weeks of culture. Our results indicate that adhesion site density but not stiffness influences the redifferentiation process of chondrocytes in 3D. This knowledge might be used to optimize the redifferentiation process of chondrocytes and thus the formation of cartilage‐like tissue. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Functionalization of reactive polymer multilayers with RGD and an antifouling motif: RGD density provides control over human corneal epithelial cell–substrate interactions
Authors: Tocce Elizabeth J. , Broderick Adam H. , Murphy Kaitlin C. , Liliensiek Sara J. , Murphy Christopher J. , Lynn David M. , Nealey Paul F. 
Published: October 2011

AbstractOur study demonstrates that substrates fabricated using a “reactive” layer‐by‐layer approach promote well‐defined cell–substrate interactions of human corneal epithelial cells. Specifically, crosslinked and amine‐reactive polymer multilayers were produced by alternating “reactive” deposition of an azlactone‐functionalized polymer [poly(2‐vinyl‐4,4‐dimethylazlactone)] (PVDMA) and a primary amine‐containing polymer [branched poly(ethylene imine)] (PEI). Advantages of our system include a 5‐ to 30‐fold decrease in deposition time compared to traditional polyelectrolyte films and direct modification of the films with peptides. Our films react with mixtures of an adhesion‐promoting peptide containing Arg‐Gly‐Asp (RGD) and the small molecule D‐glucamine, a chemical motif which is nonfouling. Resulting surfaces prevent protein adsorption and promote cell attachment through specific peptide interactions. The specificity of cell attachment via immobilized RGD sequences was verified using both a scrambled RDG peptide control as well as soluble‐RGD competitive assays. Films were functionalized with monotonically increasing surface densities of RGD which resulted in both increased cell attachment and the promotion of a tri‐phasic proliferative response of a human corneal epithelial cell line (hTCEpi). The ability to treat PEI/PVDMA films with peptides for controlled cell–substrate interactions enables the use of these films in a wide range of biological applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Long-term impact of adherence to oral bisphosphonates on osteoporotic fracture incidence
Authors: Sampalis John S , Adachi Jonathan D , Rampakakis Emmanouil , Vaillancourt Julie , Karellis Angela , Kindundu Christian 
Published: October 2011

Abstract
Adherence to osteoporosis treatments is a critical parameter resulting in suboptimal effectiveness in real-life practice. The long-term effect of adherence on fracture risk has not been assessed. This was a retrospective study using provincial health insurance claims databases to assess the association between adherence to oral bisphosphonates (OBP) and incidence of osteoporotic fractures in all Ontario patients with osteoporosis between April 1996 and December 2009. Multivariate logistic regression models were used to assess the association between OBP adherence and fracture risk. Treatment duration was classified into 2-year intervals. Compliance was estimated with the medication possession ratio (MPR), and persistence was defined as the length of continuous therapy without a gap in refills &gt;30 days. The study cohort was composed of 636,114 patients, among whom 36.1% were prescribed OBPs for 0 to 2 years, 19.7% for 2 to 4 years, 15.1% for 4 to 6 years, 12% for 6 to 8 years, 9.1% for 8 to 10 years, 6.1% for 10to 12 years, and 1.9% for 12 to 14 years. Overall, the mean (SD) compliance for the cohort was 0.72 (0.30) with 53.5% of the patients having compliance &gt;80% and 24.6% being persistent with treatment during the 14-year follow-up period. Significant associations between high adherence and reduced fracture risk over the entire 14-year period were observed; the overall odds ratio for categorical compliance (MPR &gt;80% or MPR ≤80%), continuous compliance, and persistence were 0.909 (95% confidence interval [CI] 0.893–0.925), 0.918 (95% CI 0.893–0.944), and 0.804 (95% CI 0.787–0.821), respectively. In conclusion, adherence to OBP in osteoporosis management is suboptimal in a real-life setting. A significant positive association exists between poor adherence and increased risk of osteoporotic fractures, which becomes augmented with longer treatment duration. © 2012 American Society for Bone and Mineral Research
Inhibition by zinc of deoxycholate‐induced apoptosis in HCT‐116 cells
Authors: Smith Abigail F. , Longpre Jennifer , Loo George 
Published: October 2011

AbstractThe bile acid, deoxycholate, can induce apoptosis although the effect of trace elements on such cell death is unknown. The aim of this study was to determine if deoxycholate‐induced apoptosis is influenced by zinc. HCT‐116 colon epithelial cells were pre‐treated with zinc and then exposed to deoxycholate. Membrane blebbing, formation of apoptotic bodies, and greater overall production of reactive oxygen species (ROS) occurred in cells exposed to deoxycholate, but zinc inhibited the occurrence of these three events caused by deoxycholate. Upon finer analysis, stimulation of mitochondrial superoxide production, mitochondrial dysfunction, and cytochrome c release were detected in cells exposed to deoxycholate, but zinc did not inhibit any of these three effects caused by deoxycholate. Additionally, caspase‐3 activation, plasma membrane phospholipid translocation, and also chromatin condensation and fragmentation were observed in cells exposed to deoxycholate, but all of these effects of deoxycholate, including the greater overall ROS production, were all inhibited by zinc. Because zinc did not prevent the three mitochondrial effects caused by deoxycholate, the last set of findings suggested that zinc hampered activation of an initiator caspase upstream of effector caspase‐3, in inhibiting deoxycholate‐induced HCT‐116 cell death. In examining this possibility, it was found that caspase‐8 activation caused by deoxycholate was blocked by zinc. Collectively, the results suggest that zinc can inhibit deoxycholate‐induced apoptotic cell death mediated by caspases. J. Cell. Biochem. 113: 650–657, 2012. © 2011 Wiley Periodicals, Inc.
First‐principle investigation of magnetic coupling mechanism in hypothesized A‐site‐ordered perovskite YMn3Sc4O12
Authors: Li Hongping , Lv Shuhui , Bai Yijia , Xia Yanjie , Liu Xiaojuan , Meng Jian 
Published: October 2011

AbstractWe have systematically investigated the electronic and magnetic properties of hypothesized A‐site‐ordered perovskite YMn3Sc4O12 using first‐principle calculation based on the density functional theory. Our calculated results predict that YMn3Sc4O12 is both thermodynamically and mechanically stable and its ground state is antiferromagnetic insulator. The Mn3+ is in the high‐spin state. More importantly, by comparison to YMn3Al4O12, we point out that the empty Sc 3d orbital provides the MnOScOMn superexchange interaction, which is similar to its isostructural perovskite CaCu3Ti4O12, and enhances the antiferromagnetic interaction between Mn ions. From these calculations, we can clearly see that the empty 3d orbital plays an important role to realize superexchange interaction. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
EXPLORING ACCOUNTABILITY DISCOURSES AND PRACTICES IN THE SPANISH AID SYSTEM
Authors: Boni Alejandra , Peris Jordi , McGee Rosemary , Acebillo‐Baqué Míriam , Hueso Andrés 
Published: October 2011

AbstractThis article aims to explore the different accountability discourses of the various actors in the Spanish international aid system and to examine them in light of the various theoretical interpretations of development accountability. The conclusions reached suggest a technical and financial accountability model, largely isolated from international debates where political and social issues are at the core of the concept. Although this can be explained by a range of factors which are specific to the Spanish aid system, there are also interesting tendencies that are deepening a new understanding and practice of the idea. Copyright © 2011 John Wiley & Sons, Ltd.
High doses of salicylate and aspirin are inhibitory on acid‐sensing ion channels and protective against acidosis‐induced neuronal injury in the rat cortical neuron
Authors: Wang Wei , Ye Shan‐Dong , Zhou Ke‐Qing , Wu Li‐Min , Huang Yi‐Na 
Published: October 2011

AbstractAspirin and its main metabolite salicylate are widely used to relieve pain, treat inflammatory diseases, and prevent ischemic stroke. Multiple pathways are responsible for the therapeutic actions exerted by these drugs. One of the pathways is targeting neuronal receptors/ion channels in the central nervous system. Correspondingly, increasing evidence has implicated acid‐sensing ion channels (ASICs) in the processes of the diseases that are medicated by aspirin and salicylate. We therefore employed whole‐cell patch‐clamp recordings to examine the effects of salicylate as well as aspirin on ASICs in cultured cortical neurons of the rat. We recorded rapid and reversible inhibition of ASIC current by millimolar concentrations of aspirin and salicylate and found that salicylate reduced acidosis‐induced membrane depolarization. These data suggest that ASICs in the cortex are molecular targets of high doses of aspirin and salicylate. In addition, the results from lactate dehydrogenase release measurement showed that high doses of aspirin and salicylate protected the cortical neuron from acidosis‐induced neuronal injury. These findings may contribute to a better understanding of the therapeutic mechanisms of aspirin and salicylate actions in the brain and provide new evidence on aspirin and salicylate used as neuroprotective agents in the treatment of ischemic stroke. © 2011 Wiley Periodicals, Inc.
From an Epoxide Monomer Toolkit to Functional PEG Copolymers With Adjustable LCST Behavior
Authors: Mangold Christine , Obermeier Boris , Wurm Frederik , Frey Holger 
Published: October 2011

AbstractThe lower critical solution temperature (LCST) behavior of novel poly(ethylene glycol) (PEG)‐based copolymers bearing multiple functional groups, obtained by anionic ring‐opening (co)polymerization (AROP), has been investigated. Variable comonomer ratios of ethylene oxide (EO) and the corresponding oxiranes isopropylidene glyceryl glycidyl ether (IGG), ethoxyl vinyl glycidyl ether (EVGE), allyl glycidyl ether (AGE), or N,N‐dibenzyl amino glycidyl (DBAG), particularly designed to implement functional groups at the PEG backbone, were found to influence the LCST behavior. Sharp transitions from translucent to opaque solutions, comparable to other well‐established stimuli‐responsive polymers, were observed at temperatures ranging from 9 to 82 °C. The influence of the side group hydrophobicity could be quantified by the comparison of the different copolymer systems observed.
Genetic variability in DNA repair and cell cycle control pathway genes and risk of smoking‐related lung cancer
Authors: Buch Shama C. , Diergaarde Brenda , Nukui Tomoko , Day Roger S. , Siegfried Jill M. , Romkes Marjorie , Weissfeld Joel L. 
Published: October 2011

AbstractDNA repair and cell cycle control play an important role in the repair of DNA damage caused by cigarette smoking. Given this role, functionally relevant single nucleotide polymorphisms (SNPs) in genes in these pathways may well affect the risk of smoking‐related lung cancer. We examined the relationship between 240 SNPs in DNA repair and cell cycle control pathway genes and lung cancer risk in a case–control study of white current and ex‐cigarette smokers (722 cases and 929 controls). Additive, dominant, and recessive genetic models were evaluated for each SNP. A genetic risk summary score was also constructed. Odds ratios (OR) for lung cancer risk and 95% confidence intervals (95% CI) were estimated using logistic regression models. Thirty‐eight SNPs were associated with lung cancer risk in our study population at P < 0.05. The strongest associations were observed for rs2074508 in GTF2H4 (Padditive = 0.003), rs10500298 in LIG1 (Precessive = 2.7 × 10−4), rs747658 and rs3219073 in PARP1 (rs747658: Padditive = 5.8 × 10−5; rs3219073: Padditive = 4.6 × 10−5), and rs1799782 and rs3213255 in XRCC1 (rs1799782: Pdominant = 0.006; rs3213255: Precessive = 0.004). Compared to individuals with first quartile (lowest) risk summary scores, individuals with third and fourth quartile summary score results were at increased risk for lung cancer (OR: 2.21, 95% CI: 1.66–2.95 and OR: 3.44, 95% CI: 2.58–4.59, respectively; Ptrend < 0.0001). Our data suggests that variation in DNA repair and cell cycle control pathway genes is associated with smoking‐related lung cancer risk. Additionally, combining genotype information for SNPs in these pathways may assist in classifying current and ex‐cigarette smokers according to lung cancer risk. © 2011 Wiley Periodicals, Inc.
PTBP1‐dependent regulation of USP5 alternative RNA splicing plays a role in glioblastoma tumorigenesis
Authors: Izaguirre Daisy I. , Zhu Wen , Hai Tao , Cheung Hannah C. , Krahe Ralf , Cote Gilbert J. 
Published: October 2011

AbstractAberrant RNA splicing is thought to play a key role in tumorigenesis. The assessment of its specific contributions is limited by the complexity of information derived from genome‐wide array‐based approaches. We describe how performing splicing factor‐specific comparisons using both tumor and cell line data sets may more readily identify physiologically relevant tumor‐specific splicing events. Affymetrix exon array data derived from glioblastoma (GBM) tumor samples with defined polypyrimidine tract‐binding protein 1 (PTBP1) levels were compared with data from U251 GBM cells with and without PTBP1 knockdown. This comparison yielded overlapping gene sets that comprised only a minor fraction of each data set. The identification of a novel GBM‐specific splicing event involving the USP5 gene led us to further examine its role in tumorigenesis. In GBM, USP5 generates a shorter isoform 2 through recognition of a 5′ splice site within exon 15. Production of the USP5 isoform 2 was strongly correlated with PTBP1 expression in GBM tumor samples and cell lines. Splicing regulation was consistent with the presence of an intronic PTBP1 binding site and could be modulated through antisense targeting of the isoform 2 splice site to force expression of isoform 1 in GBM cells. The forced expression of USP5 isoform 1 in two GBM cell lines inhibited cell growth and migration, implying an important role for USP5 splicing in gliomagenesis. These results support a role for aberrant RNA splicing in tumorigenesis and suggest that changes in relatively few genes may be sufficient to drive the process. © 2011 Wiley Periodicals, Inc.
New insights into the influence of cigarette smoking on urothelial carcinogenesis: Smoking‐induced gene expression in tumor‐free urothelium might discriminate muscle‐invasive from nonmuscle‐invasive urothelial bladder cancer
Authors: Gabriel Ute , Li Li , Bolenz Christian , Steidler Annette , Kränzlin Bettina , Saile Maria , Gretz Norbert , Trojan Lutz , Michel Maurice Stephan 
Published: October 2011

AbstractSmoking is the main risk factor for urothelial bladder cancer. In former smokers the risk decreases but does not reach the low level of never smokers. This indicates reversible and permanent smoking‐derived genetic alterations. Transcriptional changes may point to mechanisms, how smoking promotes urothelial bladder cancer. To identify smoking‐derived transcriptional changes we performed gene expression profiling in current, former, and never smokers, using tumor and tumor‐free urothelium from patients with nonmuscle‐invasive urothelial bladder cancer (NMIBC) or muscle‐invasive urothelial bladder cancer (MIBC). Smoking turned out to influence gene expression much less than tumor stage (NMIBC or MIBC) and tumor transformation (tumor‐free or tumor). Smoking seemed to influence gene expression in patients with MIBC more strongly compared to those with NMIBC. The least irreversible changes after smoking cessation were proposed in tumor‐free urothelium from patients with NMIBC. Growth factors and oncogenes were up‐regulated in tumor‐free urothelium from smokers with MIBC but not from smokers with NMIBC. A panel of genes up‐regulated in smokers have potential for early detection and distinction of MIBC from NMIBC using tumor‐free tissue. © 2011 Wiley Periodicals, Inc.
Akkreditierung im Wandel
Authors: Patscheke Heinrich 
Published: October 2011

AbstractAufgrund einer EU‐Verordnung gibt es seit 2010 in Deutschland nur noch eine Akkreditierungsagentur für Laboratorien, die Deutsche Akkreditierungsstelle Dakks. Kritik gibt es an ihrer Struktur, die sich inzwischen auch verändert hat, und an ihren Gebühren.
Chemical‐Driven Tissue Removal and Removal Profiles by Atmospheric Plasma Irradiation
Authors: Koo Il Gyo , Moore Cameron A. , Choi Myeong Yeol , Kim Gon Jun , Kim Paul Y. , Kim Yoon‐Sun , Yu Zengqi , Collins George J. 
Published: October 2011

AbstractWe demonstrate the application of RF‐excited plasma to remove localized regions of ex vivo tissue. While some limited tissue removal occurs when using discharges in rare gases alone, the addition of chemical precursors results in an enhancement of etch depth and etch profile under essentially identical plasma conditions of delivered power, applied voltage, and gas flow. Specifically, the material removal rate in our experiments using different CH4−xClx additives increased with both (i) the molecular chlorine content (x = 2,3,4) of the selected additive, and (ii) the concentration of haloalkane vapor in the gas stream. We attribute this enhancement to the generation and delivery of chemically reactive radicals from the plasma to the tissue, followed by formation of volatile products (i.e., a chemical, rather than physical or thermal, tissue removal process). In addition we observed that cross‐sectional etch profiles differed with the chosen haloalkane additive chemistries, indicative of corresponding differences in chemistries on profile side‐walls versus bottom walls.magnified image
Plasma Deposition of Nanoscale Difluoromethylene Dominated Surfaces
Authors: Quade Antje , Schröder Karsten , Ohl Andreas , Weltmann Klaus‐Dieter 
Published: October 2011

AbstractPolytetrafluoroethylene‐like coatings with a remarkably high amount of CF2 groups to the extent of 85% were deposited with a pulsed microwave discharge at low pressure. They were obtained by plasma enhanced chemical vapor deposition using solely octafluoropropane gas, C3F8, as precursor. The influence of gas pressure and microwave power on properties of the deposited coatings like content of CF2‐chains, F/C‐ratio, deposition rate, and wettability is described. Best results regarding a high difluoromethylene group content of the films were obtained at a pressure of 50 Pa at higher microwave powers. FTIR spectra show the two distinct absorption bands, which are assigned to the CF2 asymmetric and symmetric stretching modes, demonstrating convincingly the nature of the highly ordered PTFE‐like films.magnified image
Atmospheric Pressure Plasma CVD of Amorphous Hydrogenated Silicon Carbonitride (a‐SiCN:H) Films Using Triethylsilane and Nitrogen
Authors: Guruvenket Srinivasan , Andrie Steven , Simon Mark , Johnson Kyle W. , Sailer Robert A. 
Published: October 2011

AbstractAmorphous hydrogenated silicon carbonitride (a‐SiCN:H) thin films are synthesized by atmospheric pressure plasma enhanced chemical vapor (AP‐PECVD) deposition using the Surfx Atomflow™ 250D APPJ source with triethylsilane (HSiEt3, TES) and nitrogen as the precursor and the reactive gases, respectively. The effect of the substrate temperature (Ts) on the growth characteristics and the properties of a‐SiCN:H films was evaluated. The properties of the films were investigated via scanning electron microscopy (SEM), atomic force microscopy (AFM) for surface morphological analyses, Fourier transform infrared spectroscopy (FTIR), and X‐ray photoelectron spectroscopy (XPS) for chemical and compositional analyses; spectroscopic ellipsometry for optical properties and thickness determination and nanoindentation to determine the mechanical properties of the a‐SiCN:H films. Films deposited at low Ts depict organic like features, while the films deposited at high Ts depict ceramic like features. FTIR and XPS studies reveal that an increases in Ts helps in the elimination of organic moieties and incorporation of nitrogen in the film. Films deposited at Ts of 425 °C have an index of refraction (n) of 1.84 and hardness (H) of 14. 8 GPa. A decrease in the deposition rate between Ts of 25 and 250 °C and increase in deposition rate between Ts of 250 and 425 °C indicate that the growth of a‐SiCN:H films at lower Ts are surface reaction controlled, while at high temperatures film growth is mass‐transport controlled. Based on the experimental results, a potential route for film growth is proposed.magnified image