bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Acute Kidney Injury During Treatment with Vancomycin in Combination with Piperacillin‐Tazobactam or Cefepime
Authors: Gomes Diane M. , Smotherman Carmen , Birch Amy , Dupree Lori , Della Vecchia Bethany J. , Kraemer Dale F. , Jankowski Christopher A. 
Published: April 2014

Study ObjectiveTo evaluate the observed incidence of acute kidney injury (AKI) in adult patients receiving either piperacillin‐tazobactam and vancomycin or cefepime‐vancomycin for more than 48 hours.DesignRetrospective matched cohort.SettingLarge academic medical center.PatientsAdult patients without preexisting renal dysfunction admitted over an 8‐month time period who received either the combination of piperacillin‐tazobactam and vancomycin or cefepime‐vancomycin for more than 48 hours were evaluated forAKI, defined by the Acute Kidney Injury Network criteria.Measurements and Main ResultsA total of 224 patients receiving either antimicrobial combination were evaluated forAKI. The incidence ofAKIwas significantly higher in the piperacillin‐tazobactam and vancomycin group (34.8%) compared with the cefepime‐vancomycin group (12.5%) in the unmatched analysis (p<0.0001). After adjusting for potential sources of bias through propensity score matched pairs and conditional logistic regression, piperacillin‐tazobactam and vancomycin combination therapy (p=0.003) was an independent predictor ofAKI. There were no significant differences in time toAKIor hospital length of stay between groups.ConclusionsThe results of this study suggest that there may be an association between piperacillin‐tazobactam and vancomycin combination therapy and increased incidence ofAKI.
Efficacy and Safety of Analgosedation with Fentanyl Compared with Traditional Sedation with Propofol
Authors: Tedders Kristen M. , McNorton Kelly N. , Edwin Stephanie B. 
Published: April 2014

ObjectivesTo compare the efficacy and safety of analgosedation with fentanyl versus traditional sedation with propofol in critically ill patients receiving mechanical ventilation.MethodsRetrospective, observational study evaluating adult critically ill patients on mechanical ventilation at a community teaching hospital who received continuous infusion fentanyl (n=50) or propofol (n=50) from September 2011–March 2013.ResultsMedian duration of mechanical ventilation was similar between patients receiving propofol and fentanyl infusions (46.7 hr vs 46.0 hr, p=0.19). No difference was noted in median intensive care unit length of stay between groups (p=0.42). A larger percentage of patients receiving propofol required rescue opioids compared with patients receiving fentanyl (56% vs 34%, p=0.04). Furthermore, patients receiving propofol required significantly more rescue opioid therapy during the course of mechanical ventilation as calculated by fentanyl equivalents (150 μg vs 100 μg, p=0.03). No difference in the rate of intensive care unit delirium was noted between groups (fentanyl 23% vs propofol 27%, p=0.80).ConclusionAnalgosedation with fentanyl appears to be a safe and effective strategy to facilitate mechanical ventilation. This regimen does not appear to affect duration of mechanical ventilation when compared with propofol, but may allow for more optimal pain management in critically ill patients.
Halogeno‐modified polystyrene: monomer reactivity ratios, thermal behaviour and flammability
Authors: Wiacek Malgorzata , Wesolek Dorota , Rojewski Szymon , Bujnowicz Krzysztof , Schab‐Balcerzak Ewa 
Published: April 2014

AbstractChemical modification based on incorporation of flame retardants into polymer backbones was used in order to reduce flammability of polystyrene (PSt). The halogeno‐substituted styrenes: 4‐chlorostyrene (ClSt), 4‐bromostyrene (BrSt) and 2,3,4,5,6‐pentafluorostyrene (5FSt) were applied as reactive flame retardants. Homo‐ and copolymers of these halogeno‐substituted styrenes and styrene (St) were synthesized with various feed ratios using free radical bulk polymerization with azobisisobutyronitrile as a initiator. This yielded series of (co)polymers with various amounts of included ClSt, BrSt and 5FSt (5–50 mol% of modified St). Copolymer compositions were determined using 1H NMR spectroscopy. The relative reactivity ratios of the used comonomers were determined by applying conventional linearization methods. The Jaacks (J) method was used for systems including BrSt and ClSt monomers whereas the Fineman–Ross method was additionally used to confirm the values of reactivity ratios of St–5FSt. The reactivity ratios of comonomer pairs obtained from J plots were 0.75 and 0.38 (St–ClSt), 1.65 and 0.46 (St–BrSt), 0.44 and 0.42 (St–5FSt). Glass transition temperature and thermal stability of obtained (co)polymers were determined using differential scanning calorimetry and thermogravimetric analysis (TGA), respectively. The thermal degradation kinetic of PSt, PClSt, PBrSt and P5FSt was studied applying TGA. Kinetic parameters such as thermal decomposition activation energy (E) and frequency factor (A) were estimated using Ozawa and Kissinger models. The resulting activation energies estimated using these two methods were quite close. The values of activation energy (kJ mol−1) increased in the following order: PClSt (E(O) = 216.1) < PSt (E(O) = 219.9) < PBrSt (E(O) = 224.7) < P5FSt (E(O) = 330.9). A pyrolysis combustion flow calorimeter was applied as a tool for assessing the flammability of the synthesized (co)polymers. © 2014 Society of Chemical Industry
Cellulose nanocrystals and related nanocomposites: Review of some properties and challenges
Authors: Mariano Marcos , El Kissi Nadia , Dufresne Alain 
Published: April 2014

ABSTRACTCellulosic nanoparticles with high Young's modulus, crystallinity, specific surface area, and aspect ratio can be found in the natural structure of plant fibers. Indeed, lignocellulosic fibers consist of semicrystalline cellulose nanofibrils embedded in an amorphous matrix mainly composed of lignin and hemicelluloses. These nanostructures give the mechanical strength to higher plant cells, and are biodegradable, renewable, resistant, and widely available to produce nanocomposites with low density, and improved and controlled mechanical, optical, and barrier properties. Nanoparticles can be extracted from cellulose using a top‐down mechanically or chemically assisted deconstructing strategy, and owing to their highly reactive surface ensuing nanomaterials can be chemically modified to tailor their properties for a wide range of applications. This review is limited to cellulose chemically extracted nanocrystals and aims to provide an overview about several aspects that involve this material, including sources, properties, challenges, and perspectives. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 791–806
Enhancing the PLA crystallization rate by incorporating a polystyrene‐block‐poly(methyl methacrylate) block copolymer: Synergy of polystyrene and poly(methyl methacrylate) segments
Authors: Wu Chien‐Pang , Wang Cheng‐Chien , Chen Chuh‐Yung 
Published: April 2014

ABSTRACTA polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) exhibiting a well‐defined structure was prepared combining anionic polymerization and mercaptan/ε‐caprolactam living polymerization. To evaluate how this block copolymer affected the crystallization of polylactide (PLA), 0.5 wt % thiol‐terminated PS homopolymer (PSSH), PMMA, and PS‐b‐PMMA was melt‐blended with PLA. The calorimetric characterization of the nonisothermal and isothermal crystallization behavior was analyzed according to Avrami's theory, indicating that PS‐b‐PMMA more effectively increased the crystallization kinetics of the PLA matrix than did PSSH or PMMA. The results revealed that the synergistic effect of the PS and PMMA blocks appeared only when they were simultaneously presented in the PLA matrix. The PS block increased the number of nucleation sites and decreased the spherulite size, whereas the PMMA block facilitated the excellent dispersion of PS‐b‐PMMA in the PLA matrix as shown in polarizing optical microscope experiments. Incorporating PS‐b‐PMMA improved the PLA crystallization rate by promoting heterogeneous nucleation. In addition, incorporating 0.5 wt % PS‐b‐PMMA increased the relative crystallinity of PLA to 43.5%, and decreased the crystallization half‐time to 2.4 min when the blend was isothermal at 105 °C. The PLA crystal structure was unchanged by the presence of PS‐b‐PMMA; however, the crystallization rate was enhanced as probed by SEM and X‐ray diffraction. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 823–832
Formation of a polycrystalline film of donor material on PEDOT:PSS buffer induced by crystal nucleation
Authors: Harano Koji , Okada Satoshi , Furukawa Shunsuke , Tanaka Hideyuki , Nakamura Eiichi 
Published: April 2014

ABSTRACTPoly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is the most popular anode buffer coated on indium tin oxide. It is thought to improve the inorganic–organic contact, but little is known about its role in organic–organic contact. This study addresses the latter issue by examining how the PEDOT:PSS layer affects the crystallization process of the neighboring layer composed of p‐type organic semiconductors in an organic photovoltaic device. Low landing voltage scanning electron microscopic analysis of crystals and aggregates of two donor compounds, tetrabenzoporphyrin (BP) and poly(3‐hexylthiophene) (P3HT), showed that PEDOT:PSS effectively nucleates the crystallization or aggregation of the donor material on its surface to form a uniformly thick film of polycrystalline BP or aggregated P3HT molecules. By contrast, a graphitic surface cannot induce structural order of the donor molecules on it. This result implies that pinning of the donor molecules to the acidic PEDOT:PSS surface promotes the heterogeneous nucleation at the organic–organic interface. © 2014 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014, 52, 833–841
Crystal structure of the Campylobacter jejuni CmeC outer membrane channel
Authors: Su Chih‐Chia , Radhakrishnan Abhijith , Kumar Nitin , Long Feng , Bolla Jani Reddy , Lei Hsiang‐Ting , Delmar Jared A. , Do Sylvia V. , Chou Tsung‐Han , Rajashankar Kanagalaghatta R. , Zhang Qijing , Yu Edward W. 
Published: April 2014

AbstractAs one of the world's most prevalent enteric pathogens, Campylobacter jejuni is a major causative agent of human enterocolitis and is responsible for more than 400 million cases of diarrhea each year. The impact of this pathogen on children is of particular significance. Campylobacter has developed resistance to many antimicrobial agents via multidrug efflux machinery. The CmeABC tripartite multidrug efflux pump, belonging to the resistance‐nodulation‐cell division (RND) superfamily, plays a major role in drug resistant phenotypes of C. jejuni. This efflux complex spans the entire cell envelop of C. jejuni and mediates resistance to various antibiotics and toxic compounds. We here report the crystal structure of C. jejuni CmeC, the outer membrane component of the CmeABC tripartite multidrug efflux system. The structure reveals a possible mechanism for substrate export.
Structural evolution and membrane interactions of Alzheimer's amyloid‐beta peptide oligomers: New knowledge from single‐molecule fluorescence studies
Authors: Johnson Robin D. , Steel Duncan G. , Gafni Ari 
Published: April 2014

AbstractAmyloid‐β peptide (Aβ) oligomers may represent the proximal neurotoxin in Alzheimer's disease. Single‐molecule microscopy (SMM) techniques have recently emerged as a method for overcoming the innate difficulties of working with amyloid‐β, including the peptide's low endogenous concentrations, the dynamic nature of its oligomeric states, and its heterogeneous and complex membrane interactions. SMM techniques have revealed that small oligomers of the peptide bind to model membranes and cells at low nanomolar‐to‐picomolar concentrations and diffuse at rates dependent on the membrane characteristics. These methods have also shown that oligomers grow or dissociate based on the presence of specific inhibitors or promoters and on the ratio of Aβ40 to Aβ42. Here, we discuss several types of single‐molecule imaging that have been applied to the study of Aβ oligomers and their membrane interactions. We also summarize some of the recent insights SMM has provided into oligomer behavior in solution, on planar lipid membranes, and on living cell membranes. A brief overview of the current limitations of the technique, including the lack of sensitive assays for Aβ‐induced toxicity, is included in hopes of inspiring future development in this area of research.
The mechanism of binding of the KIX domain to the mixed lineage leukemia protein and its allosteric role in the recognition of c‐Myb
Authors: Toto Angelo , Giri Rajanish , Brunori Maurizio , Gianni Stefano 
Published: April 2014

AbstractThe KIX domain is a mediator of the interaction between different transcription factors. This complex function is carried out via two distinct binding sites located on opposite sides of the protein; namely, the ‘c‐Myb site’ and the ‘MLL site’, named after their characteristic ligands—the transactivation domain of c‐Myb and the mixed lineage leukemia protein (MLL). Both these ligands are unstructured in isolation and fold only upon binding, posing the KIX domain as an ideal candidate to explore the binding induced folding reaction of intrinsically unstructured proteins. Here, we complement the recent kinetic description on the interaction between KIX and c‐Myb, by characterizing the binding kinetics between KIX and MLL, at different pH and ionic strength conditions. Furthermore, we analyze quantitatively the mechanism of allosteric communication between the topologically distinct c‐Myb and MLL sites. The implications of our results are discussed in the light of previous work on other intrinsically unstructured systems.
Measuring membrane protein bond orientations in nanodiscs via residual dipolar couplings
Authors: Bibow Stefan , Carneiro Marta G. , Sabo T. Michael , Schwiegk Claudia , Becker Stefan , Riek Roland , Lee Donghan 
Published: April 2014

AbstractMembrane proteins are involved in numerous vital biological processes. To understand membrane protein functionality, accurate structural information is required. Usually, structure determination and dynamics of membrane proteins are studied in micelles using either solution state NMR or X‐ray crystallography. Even though invaluable information has been obtained by this approach, micelles are known to be far from ideal mimics of biological membranes often causing the loss or decrease of membrane protein activity. Recently, nanodiscs, which are composed of a lipid bilayer surrounded by apolipoproteins, have been introduced as a more physiological alternative than micelles for NMR investigations on membrane proteins. Here, we show that membrane protein bond orientations in nanodiscs can be obtained by measuring residual dipolar couplings (RDCs) with the outer membrane protein OmpX embedded in nanodiscs using Pf1 phage as an alignment medium. The presented collection of membrane protein RDCs in nanodiscs represents an important step toward more comprehensive structural and dynamical NMR‐based investigations of membrane proteins in a natural bilayer environment.
Magnetoelastic coupling and the formation of adaptive martensite in magnetic shape memory alloys
Authors: Gruner Markus Ernst , Fähler Sebastian , Entel Peter 
Published: April 2014

Reviewing the results of recent first‐principles calculations, we work out a close analogy between the two paradigmatic classes of magnetic shape memory materials, the ordered Ni2MnGa Heusler compound and the disordered Fe70Pd30alloy. Despite fundamental differences between both systems, we can demonstrate that in both cases the very low formation energy for tetragonal twins on the smallest length scale opens an alternative transformation path into an adaptive hierarchical microstructure which is important for the functional behavior. The low energy of the (101) twin boundary corresponds to a shear instability which is associated to the soft transversal acoustic phonon in both systems. In turn, changes of the energy landscape upon magnetic disorder are responsible for the stability of austenite. This points out the strong influence of magnetoelastic coupling on the transformation process.Nanotwinned adaptive microstructures in Ni2MnGa and Fe68Pd32magnetic shape memory alloys obtained from first‐principles calculations.
On handling negative transfer and imbalanced distributions in multiple source transfer learning
Authors: Ge Liang , Gao Jing , Ngo Hung , Li Kang , Zhang Aidong 
Published: April 2014

AbstractTransfer learning has benefited many real‐world applications where labeled data are abundant in source domains but scarce in the target domain. As there are usually multiple relevant domains where knowledge can be transferred, multiple source transfer learning (MSTL) has recently attracted much attention. However, we are facing two major challenges when applying MSTL. First, without knowledge about the difference between source and target domains, negative transfer occurs when knowledge is transferred from highly irrelevant sources. Second, existence of imbalanced distributions in classes, where examples in one class dominate, can lead to improper judgement on the source domains' relevance to the target task. Since existing MSTL methods are usually designed to transfer from relevant sources with balanced distributions, they will fail in applications where these two challenges persist. In this article, we propose a novel two‐phase framework to effectively transfer knowledge from multiple sources even when there exists irrelevant sources and imbalanced class distributions. First, an effective supervised local weight scheme is proposed to assign a proper weight to each source domain's classifier based on its ability of predicting accurately on each local region of the target domain. The second phase then learns a classifier for the target domain by solving an optimization problem which concerns both training error minimization and consistency with weighted predictions gained from source domains. A theoretical analysis shows that as the number of source domains increases, the probability that the proposed approach has an error greater than a bound is becoming exponentially small. We further extend the proposed approach to an online processing scenario to conduct transfer learning on continuously arriving data. Extensive experiments on disease prediction, spam filtering and intrusion detection datasets demonstrate that: (i) the proposed two‐phase approach outperforms existing MSTL approaches due to its ability of tackling negative transfer and imbalanced distribution challenges, and (ii) the proposed online approach achieves comparable performance to the offline scheme.
Causal inference of interaction effects with inverse propensity weighting, G‐computation and tree‐based standardization
Authors: Kang Joseph , Su Xiaogang , Liu Lei , Daviglus Martha L. 
Published: April 2014

AbstractGiven the recent interest of subgroup‐level studies and personalized medicine, health research with causal inference has been developed for interaction effects of measured confounders. In estimating interaction effects, the inverse of the propensity weighting (IPW) method has been widely advocated despite the immediate availability of other competing methods such as G‐computation estimates. This paper compares the advocatedIPWmethod, the G‐computation method, and our new Tree‐based standardization method, which we call the Interaction effect Tree (IT). TheITprocedure uses a likelihood‐based decision rule to divide the subgroups into homogeneous groups where the G‐computation can be applied. Our simulation studies indicate that theIT‐based method along with the G‐computation works robustly while the advocatedIPWmethod needs some caution in its weighting. We applied theIT‐based method to assess the effect of being overweight or obese on coronary artery calcification (CAC) in the Chicago Healthy Aging Study cohort.
Asymmetrical expression of BDNF and NTRK3 genes in frontoparietal cortex of stress‐resilient rats in an animal model of depression
Authors: Farhang Sara , Barar Jaleh , Fakhari Ali , Mesgariabbasi Mehran , Khani Sajjad , Omidi Yadollah , Farnam Alireza 
Published: April 2014

ABSTRACTThe current study is based on the “approach–withdrawal” theory of emotional regulation and lateralization of brain function in rodents, which has little been studied. The aim was to indentify asymmetry in hemispheric genes expression during depression. Depressive‐like symptoms were induced in rats using chronic mild stress protocol. The sucrose consumption test was performed to identify the anhedonic and stress‐resilient rats. After decapitation, RNA was extracted from frontotemporal cortex of both hemispheres of anhedonic and stress‐resilient rats. The pattern of gene expression in these samples was compared with controls by real‐time polymerase chain reaction. A linear mixed model analysis of variance was fitted to the data to estimate the effect of rat line. From the total of 30 rats in the experimental group, five rats were identified to be anhedonic and five were stress‐resilient, according to the result of sucrose‐consumption test. BDNF and NTRK‐3 were expressed at significantly lower levels in the right hemisphere of anhedonic rats compared with stress‐resilient rats. No significant difference was found between left hemispheres. Hemispheric asymmetry in the level of gene expression was only observed for the BDNF gene in stress‐resilient rats, upregulated in right hemisphere compared with the left. Expression of NTRK3, HTR2A, COMT, and SERT was not lateralized. There was no significant asymmetry between hemispheres of anhedonic rats. This study supports the evidence for the role of genes responsible for neural plasticity in pathophysiology of depression, emphasizing probable hemispheric asymmetry at level of gene expression. Synapse, 2014. © 2014 Wiley Periodicals, Inc.
Hypothyroxinemia induced by maternal mild iodine deficiency impairs hippocampal myelinated growth in lactational rats
Authors: Wei Wei , Wang Yi , Dong Jing , Wang Yuan , Min Hui , Song Binbin , Shan Zhongyan , Teng Weiping , Xi Qi , Chen Jie 
Published: April 2014

ABSTRACTHypothyroxinemia induced by maternal mild iodine deficiency causes neurological deficits and impairments of brain function in offspring. Hypothyroxinemia is prevalent in developing and developed countries alike. However, the mechanism underlying these deficits remains less well known. Given that the myelin plays an important role in learning and memory function, we hypothesize that hippocampal myelinated growth may be impaired in rat offspring exposed to hypothyroxinemia induced by maternal mild iodine deficiency. To test this hypothesis, the female Wistar rats were used and four experimental groups were prepared: (1) control; (2) maternal mild iodine deficiency diet inducing hypothyroxinemia; (3) hypothyroidism induced by maternal severe iodine deficiency diet; (4) hypothyroidism induced by maternal methimazole water. The rats were fed the diet from 3 months before pregnancy to the end of lactation. Our results showed that the physiological changes occuring in the hippocampal myelin were altered in the mild iodine deficiency group as indicated by the results of immunofluorescence of myelin basic proteins on postnatal day 14 and postnatal day 21. Moreover, hypothyroxinemia reduced the expressions of oligodendrocyte lineage transcription factor 2 and myelin‐related proteins in the treatments on postnatal day 14 and postnatal day 21. Our data suggested that hypothyroxinemia induced by maternal mild iodine deficiency may impair myelinated growth of the offspring. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1264–1274, 2015.