bluuebunny/crossref_metadata_2025_split huggingface dataset:
Is this STS work‐related? ISO 1999 predictions as an adjunct to clinical judgment
Authors: Dobie Robert A. 
Published: October 2015

BackgroundPhysicians and audiologists are often asked to decide whether standard threshold shifts (STSs) are work‐related; epidemiological data can inform these decisions.MethodsPredictions of ISO (2013) for both age‐related and noise‐induced threshold shifts, for the 2, 3, and 4 kHz average used in calculating OSHA STSs, are presented, in tables, graphs, and an Excel spreadsheet calculator. Specifically, the ISO 1999 model estimates age‐related thresholds based on age and sex; it estimates noise‐induced threshold shifts based on noise level and duration. It specifies that to estimate the final hearing thresholds for a person of given percentile, age, sex, and noise exposure, the expected age‐related threshold is to be added to the expected noise‐induced threshold shift. Examples show how these data can predict the relative contributions of aging and occupational noise to an STS.ResultsEarly‐career STSs, especially with high levels of noise exposure, are more likely to be primarily noise‐induced. After the first decade of exposure, most STSs will be primarily age‐related.ConclusionGiven a worker's age, sex, and occupational noise exposure history, ISO 1999 estimates of the expected contributions of aging and noise can supplement clinical judgment. Am. J. Ind. Med. 58:1311–1318, 2015. © 2015 Wiley Periodicals, Inc.
Comparative fluxome and metabolome analysis for overproduction of succinate in Escherichia coli
Authors: Taymaz‐Nikerel Hilal , De Mey Marjan , Baart Gino J. E. , Maertens Jo , Foulquié‐Moreno Maria Remedios , Charlier Daniel , Heijnen Joseph J. , van Gulik Walter M. 
Published: October 2015

ABSTRACTAn aerobic succinate‐producing Escherichia coli mutant was compared to its wild‐type by quantitatively analyzing both the metabolome and fluxome, during glucose‐limited steady‐state and succinate excess dynamic conditions, in order to identify targets for further strain engineering towards more efficient succinate production. The mutant had four functional mutations under the conditions investigated: increased expression of a succinate exporter (DcuC), deletion of a succinate importer (Dct), deletion of succinate dehydrogenase (SUCDH) and expression of a PEP carboxylase (PPC) with increased capacity due to a point mutation. The steady‐state and dynamic patterns of the intracellular metabolite levels and fluxes in response to changes were used to locate the quantitative differences in the physiology/metabolism of the mutant strain. Unexpectedly the mutant had a higher energy efficiency, indicated by a much lower rate of oxygen consumption, under glucose‐limited conditions, caused by the deletion of the transcription factors IclR and ArcA. Furthermore the mutant had a much lower uptake capacity for succinate (26‐fold) and oxygen (17‐fold under succinate excess) compared to the wild‐type strain. The mutant strain produced 7.9 mmol.CmolX−1.h−1 succinate during chemostat cultivation, showing that the choice of the applied genetic modifications was a successful strategy. Furthermore, the applied genetic modifications resulted in multiple large changes in metabolite levels (FBP, pyruvate, 6PG, NAD+/NADH ratio, α‐ketogluarate) corresponding to large changes in fluxes. Compared to the wild‐type a considerable flux shift occurred from the tricarboxylic acid (TCA) cycle to the oxidative part of the pentose phosphate pathway, including an inversion of the pyruvate kinase flux. The mutant responded very differently to excess of succinate, with a remarkable possible reversal of the TCA cycle. The mutant and the wild‐type both showed homeostatic behaviour with respect to the energy charge. In contrast, large changes in redox ratios (NAD+/NADH) occurred in the wild‐type, while the mutant showed even larger changes. This large redox change can be associated to the reversal of flux directions. The observed large flexibility in the central metabolism following genetic (deletions) and environmental (substrate excess) perturbations of the mutant, indicates that introducing a more efficient succinate exporter could result in an even higher succinate production rate. Biotechnol. Bioeng. 2016;113: 817–829. © 2015 Wiley Periodicals, Inc.
The experimental teaching reform in biochemistry and molecular biology for undergraduate students in Peking University Health Science Center
Authors: Yang Xiaohan , Sun Luyang , Zhao Ying , Yi Xia , Zhu Bin , Wang Pu , Lin Hong , Ni Juhua 
Published: October 2015

AbstractSince 2010, second‐year undergraduate students of an eight‐year training program leading to a Doctor of Medicine degree or Doctor of Philosophy degree in Peking University Health Science Center (PKUHSC) have been required to enter the “Innovative talent training project.” During that time, the students joined a research lab and participated in some original research work. There is a critical educational need to prepare these students for the increasing accessibility of research experience. The redesigned experimental curriculum of biochemistry and molecular biology was developed to fulfill such a requirement, which keeps two original biochemistry experiments (Gel filtration and Enzyme kinetics) and adds a new two‐experiment component called “Analysis of anti‐tumor drug induced apoptosis.” The additional component, also known as the “project‐oriented experiment” or the “comprehensive experiment,” consists of Western blotting and a DNA laddering assay to assess the effects of etoposide (VP16) on the apoptosis signaling pathways. This reformed laboratory teaching system aims to enhance the participating students overall understanding of important biological research techniques and the instrumentation involved, and to foster a better understanding of the research process all within a classroom setting. Student feedback indicated that the updated curriculum helped them improve their operational and self‐learning capability, and helped to increase their understanding of theoretical knowledge and actual research processes, which laid the groundwork for their future research work. © 2015 by The International Union of Biochemistry and Molecular Biology, 43:428–433, 2015.
A Comparative Analysis of Acyl‐Homoserine Lactone Synthase Assays
Authors: Shin Daniel , Frane Nicole D. , Brecht Ryan M. , Keeler Jesse , Nagarajan Rajesh 
Published: October 2015

AbstractQuorum sensing is cell‐to‐cell communication that allows bacteria to coordinate attacks on their hosts by inducing virulent gene expression, biofilm production, and other cellular functions, including antibiotic resistance. AHL synthase enzymes synthesize N‐acyl‐l‐homoserine lactones, commonly referred to as autoinducers, to facilitate quorum sensing in Gram‐negative bacteria. Studying the synthases, however, has proven to be a difficult road. Two assays, including a radiolabeled assay and a colorimetric (DCPIP) assay are well‐documented in literature to study AHL synthases. In this paper, we describe additional methods that include an HPLC‐based, C−S bond cleavage and coupled assays to investigate this class of enzymes. In addition, we compare and contrast each assay for both acyl‐CoA‐ and acyl‐ACP‐utilizing synthases. The expanded toolkit described in this study should facilitate mechanistic studies on quorum sensing signal synthases and expedite discovery of antivirulent compounds.
Titanium Dioxide Reinforced Metal–Organic Framework Pd Catalysts: Activity and Reusability Enhancement in Alcohol Dehydrogenation Reactions and Improved Photocatalytic Performance
Authors: Tilgner Dominic , Friedrich Martin , Hermannsdörfer Justus , Kempe Rhett 
Published: October 2015

AbstractPorous coordination polymers or metal–organic frameworks have been proposed as promising catalyst materials since their discovery. A fundamental problem associated with MOF‐based catalysts is the stability during their catalytic performance, especially in liquid‐phase catalysis. Herein, we report on the controlled incorporation of nanoscale palladium and titanium dioxide inside MIL‐101 (Cr). The introduction of the metal species was accomplished by metal–organic chemical vapor deposition and can be varied over a large weight‐percentage range. The enhanced catalytic activity and the improved reusability of the resulting Pd/TiO2@MIL‐101 composite materials were demonstrated in hydrogenation and dehydrogenation reactions. Furthermore, the presence of TiO2 (amorphous) allowed observing an enhanced photocatalytic activity.
Probing the Size and Shape Effects of Cubic‐ and Spherical‐Shaped Palladium Nanoparticles in the Electrooxidation of Formic Acid
Authors: Zheng Weiran , Qu Jin , Hong Xinlin , Tedsree Karaked , Tsang Shik Chi Edman 
Published: October 2015

AbstractA systematic study of size and shape effects in the electrooxidation of formic acid over our controlled synthesized Pd nanospheres and nanocubes as material models by using infrared spectroscopy and density functional calculations was undertaken. The bridge formate intermediate on the metal terrace was identified as the main contributor to the electrooxidation activity of formic acid, whereas linear formate with much weaker adsorption energy was unstable and could not proceed to the product. It was also demonstrated that Pd(1 0 0) cubes could stabilize two bridge formate species, and thus, they show higher electrooxidation activity than Pd spheres at comparable sizes.
An Organocatalytic Regiospecific Synthesis of 1,5‐Disubstituted 4‐Thio‐1,2,3‐triazoles and 1,5‐Disubstituted 1,2,3‐Triazoles
Authors: Ramachary Dhevalapally B. , Krishna Patoju M. , Gujral Jagjeet , Reddy G. Surendra 
Published: October 2015

AbstractOrganocatalytic azide–ketone [3+2] cycloaddition (OrgAKC) of a variety of 1‐aryl‐2‐(arylthio)ethanones and 1‐alkyl‐2‐(alkylthio)ethanones with different aryl or alkyl azides is reported in dimethyl sulfoxide or solvent‐free under ambient conditions to furnish 1,5‐disubstituted 4‐thio‐1,2,3‐triazoles in a regiospecific manner, which are further converted into useful 1,5‐disubstituted 1,2,3‐triazoles by treatment with Raney Ni at 25 °C for 1–3 h. Notable features of the OrgAKC reaction include high rate and selectivity, solvent‐free conditions, easily available substrates and catalysts, a wide range of synthetic and medicinal applications, and excellent yields generating a vast library of triazoles.
A novel switched frequency 3He/1H high‐pass birdcage coil for imaging at 1.5 tesla
Authors: Pratt Ronald , Giaquinto Randy , Ireland Christopher , Daniels Barret , Loew Wolfgang , Higano Nara , Cao Xuefeng , Thomen Robert , Woods Jason , Dumoulin Charles L. 
Published: October 2015

ABSTRACTThe ability to produce hyperpolarized noble gases 3He and 129Xe has opened up exciting possibilities for pulmonary magnetic resonance imaging (MRI). We have recently built a hyperpolarizer with the goal of using hyperpolarized 3He gas for MRI in neonatal lungs in a dedicated small foot‐print 1.5 T MR scanner developed at our institution and sited in our Neonatal Intensive Care Unit. Although hyperpolarized gas imaging can provide unique insights into lung ventilation, acinar microstructure, and gas‐exchange dynamics, there is an undiminished need for 1H MRI of the lung to provide anatomic references, B1 and B0 maps, and 1H images of lung parenchyma. To address this need, we designed, built and tested a novel radiofrequency body coil that provides a high‐pass birdcage coil that can be used for both 3He and 1H frequencies (48.65 and 63.86 MHz, respectively, at 1.5 T). To switch between frequencies, the birdcage coil has a large mechanical actuator that simultaneously changes the capacitance between every rung of the birdcage. Advantages of this coil design include: 1) quadrature excitation and reception at the 3He and 1H frequencies, 2) identical B1 field maps for 3He and 1H imaging, 3) excellent signal‐to‐noise ratio and B1 homogeneity at both frequencies, and 4) rapid (10–20 s) switching times between 3He and 1H operation. This report provides details of the coil's design and fabrication. Images of hyperpolarized 3He and 1H in phantoms and ex vivo rabbit lungs demonstrate the image quality obtained with the coil. © 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 45B: 174–182, 2015
The role of obestatin in roux‐en‐Y gastric bypass‐induced remission of type 2 diabetes mellitus
Authors: Wang Jian‐li , Xu Xian‐hui , Zhang Xue‐jun , Li Wei‐hua 
Published: October 2015

SummaryType 2 diabetes mellitus (T2DM) is a complex and multifactorial disease that is generally characterized by insulin resistance and loss of β‐cell function that develops in adulthood. To date, more than 6% of the world's population is affected by T2DM. The main treatments of T2DM are dietary and lifestyle changes. However, only dependent on behaviour modification and oral hypoglycemics, many patients are unable to maintain glycemic control. Emerging evidence indicates that up to 80% of patients with T2DM undergoing Roux‐en‐Y gastric bypass (RYGB) experience complete remission of their T2DM and the majority of remissions occur almost immediately following the operation. Obestatin is a 23‐amino‐acid peptide, which is not only thought to suppress food intake and decrease gastric emptying but also found to exert survival effects in pancreatic β cells, increase glucose‐stimulated insulin secretion, and reduce insulin resistance and inflammation. In addition, some researchers demonstrated that obestatin is a nutritional marker reflecting body adiposity and insulin resistance. Although results from previous studies were conflicting, the peripheral blood concentrations of obestatin were changed after RYGB. Therefore, regulation of obestatin level may be another mechanism for RYGB‐induced remission of T2DM. In this article, we review briefly the effect of RYGB on T2DM in humans and offer an overview of the published data on the effects of RYGB on obestatin level in patients with T2DM. Furthermore, the possible roles of obestatin in the remission of T2DM following RYGB are also reviewed. Copyright © 2015 John Wiley & Sons, Ltd.
Outdoor characterization and comparison of string and MLPE under clear and partially shaded conditions
Authors: Sinapis Kostas , Litjens Geert , van den Donker Menno , Folkerts Wiep , van Sark Wilfried 
Published: October 2015

AbstractBuilding integrated and building attached photovoltaic (BIPV, BAPV) systems may suffer from lower performance than predicted as a result of unwanted partial shading. New system architectures have been proposed to optimize performance. The common approach of these new architectures is to track the maximum power point of every solar module individually. This paper demonstrates the effect of shading on energy yield by evaluating power level management on the module level compared to string level. Three independent PV systems were installed and extensively monitored in Eindhoven, a reference string inverter system, a power optimizer system and a micro inverter system. The DC and AC performance ratio (PR) of the systems have been analyzed for different weather types based on the clearness index. A pole shading covering 1–2% of the total system surface has been used to evaluate system performance under a specific type of partial shading. Module Level Power Electronics (MLPE) is capable of increasing the PR up to 35% under certain partial shading conditions. However, the string inverter system outperformed MLPE under unshaded operation conditions.
Stage susceptibility of Japanese medaka (Oryzias latipes) to selenomethionine and hypersaline developmental toxicity
Authors: Kupsco Allison , Schlenk Daniel 
Published: October 2015

Abstract

Anthropogenic disturbance of seleniferous soils can lead to selenium contamination of waterways. Although selenium is an essential micronutrient, bioaccumulation and maternal transfer of proteinaceous selenomethionine (SeMet) can result in embryo toxicity. Furthermore, as the climate changes, the salinity of spawning grounds in water-restrained estuaries is increasing. Although a small increase in salinity may not directly impact adult fish, it may alter the detoxification strategies of developing organisms. Previous research indicates that hypersalinity may potentiate SeMet embryo toxicity at an early developmental stage. However, embryonic development is a complex, spatiotemporal process with a constantly shifting cellular microenvironment. To generate thresholds and an adverse outcome pathway for the interactions between selenium and salinity, we sought to identify windows of susceptibility for lethality and deformities in the Japanese medaka (Oryzias latipes). Embryos were treated in freshwater or saltwater for 24 h with 0.5 µM, 5 µM, and 50 µM SeMet at 6 different developmental stages (9, 17, 25, 29, 34, and 38). Survival, hatch, deformities (total, type, and severity), and days to hatch were quantified. Selenium embryo tissue measurements were performed. Selenomethionine exposures of 5 µM and 50 µM significantly decreased survival and hatch at all stages. However, SeMet uptake was stage-dependent and increased with stage. Stage 17 (early neurulation) was identified as the most susceptible stage for lethality and deformities. Selenomethionine in saltwater caused significantly greater toxicity than freshwater at stage 25 (early organogenesis), suggesting a role for liver and osmoregulatory organogenesis in toxicity. Environ Toxicol Chem 2016;35:1247–1256. © 2015 SETAC
Relative sensitivities among avian species to individual and mixtures of aryl hydrocarbon receptor–active compounds
Authors: Wei Fenghua , Li Juanying , Zhang Rui , Xia Pu , Peng Ying , Giesy John P. , Zhang Xiaowei 
Published: October 2015

Abstract

Dioxins and dioxin-like compounds (DLCs) are potent toxicants to most vertebrates. Sensitivities to DLCs vary among species. In the present study, the sensitivities of avian species (chicken [Gallus gallus], ring-necked pheasant [Phasianus colchicus], and Japanese quail [Coturnix japonica]) to some polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were determined by using species-specific, in vitro, transactivation assays based on a luciferase reporter gene under control of species-specific aryl hydrocarbon receptors. In ring-necked pheasant and Japanese quail, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was not the most potent inducer of toxic effects. Especially for Japanese quail, the relative potency values of most of 9 PCDD/Fs tested were greater than for TCDD. The rank order of avian species sensitivities to DLCs was chicken &gt; ring-necked pheasant &gt; Japanese quail. Effects of binary mixtures of TCDD, 2,3,7,8-tetrachlorodibenzofuran, and 2,3,4,7,8-pentachlorodibenzofuran were strictly additive. Moreover, we also found that the primary DLCs that were responsible for most of the potency of the DLC mixtures can be deduced by using ordination in a multidimensional space defined by the avian species sensitivities. Overall, the relative potency and the species sensitivities of these chemicals could guide risk assessments to wild species when exposure to mixtures of DLCs in the environment. Environ Toxicol Chem 2016;35:1239–1246. © 2015 SETAC
A fugacity-based toxicokinetic model for narcotic organic chemicals in fish
Authors: Celsie Alena , Mackay Donald , Parnis J. Mark , Arnot Jon A. 
Published: October 2015

Abstract

A novel dynamic fugacity-based model is described, developed, and tested that simulates the uptake of narcotic organic chemicals in fish from water as occurs in aquatic bioconcentration and toxicity tests. The physiologically based toxicokinetic model treats the time course of chemical distribution in 4 compartments (tissue groups) in the fish, including the liver, in which biotransformation may occur. In addition to calculating bioconcentration and toxicokinetics, 5 possible toxic endpoints are defined corresponding to chemical concentration, fugacity, or activity reaching a critical value that causes 50% mortality. The mathematical description of multicompartment uptake is simplified by expressing the equations in the fugacity format. The model is parameterized and tested against reported empirical data for the bioconcentration of pentachloroethane in rainbow trout and for uptake and mortality from aquatic exposures to naphthalene and 1,2,4-trichlorobenzene in fathead minnows. Model performance is evaluated, and it is concluded that with suitable parameterization it has potential for application for assessment of both bioconcentration and toxicity expressed as median lethal concentrations, critical body residues, and chemical activity as a function of time to death. Environ Toxicol Chem 2016;35:1257–1267. © 2015 SETAC
A simple assessment model to quantifying the dynamic hippocampal neurogenic process in the adult mammalian brain
Authors: Choi Minee L. , Begeti Faye , Barker Roger A. , Kim Namho 
Published: October 2015

ABSTRACTAdult hippocampal neurogenesis is a highly dynamic process in which new cells are born, but only some of which survive. Of late it has become clear that these surviving newborn neurons have functional roles, most notably in certain forms of memory. Conventional methods to look at adult neurogenesis are based on the quantification of the number of newly born neurons using a simple cell counting methodology. However, this type of approach fails to capture the dynamic aspects of the neurogenic process, where neural proliferation, death and differentiation take place continuously and simultaneously. In this paper, we propose a simple mathematical approach to better understand the adult neurogenic process in the hippocampus which in turn will allow for a better analysis of this process in disease states and following drug therapies. © 2015 Wiley Periodicals, Inc.
Is the chronic Tier-1 effect assessment approach for insecticides protective for aquatic ecosystems?
Authors: Brock Theo CM , Bhatta Ranjana , van Wijngaarden René PA , Rico Andreu 
Published: October 2015

Abstract
We investigated the appropriateness of several methods, including those recommended in the Aquatic Guidance Document of the European Food Safety Authority (EFSA), for the derivation of chronic Tier-1 regulatory acceptable concentrations (RACs) for insecticides and aquatic organisms. The insecticides represented different chemical classes (organophosphates, pyrethroids, benzoylureas, insect growth regulators, biopesticides, carbamates, neonicotinoids, and miscellaneous). Chronic Tier-1 RACs derived using toxicity data for the standard species Daphnia magna, Chironomus spp., and/or Americamysis bahia, were compared with Tier-3 RACs derived from micro- and mesocosm studies on basis of the ecological threshold option (ETO-RACs). ETO-RACs could be derived for 31 insecticides applied to micro- and mesocosms in single or multiple applications, yielding a total number of 36 cases for comparison. The chronic Tier-1 RACs calculated according to the EFSA approach resulted in a sufficient protection level, except for 1 neonicotinoid (slightly underprotective) and for several pyrethroids if toxicity data for A. bahia were not included. This latter observation can be explained by 1) the fact that A. bahia is the most sensitive standard test species for pyrethroids, 2) the hydrophobic properties of pyrethroids, and 3) the fact that long-term effects observed in (epi) benthic arthropods may be better explained by exposure via the sediment than via overlying water. Besides including toxicity data for A. bahia, the protection level for pyrethroids can be improved by selecting both D. magna and Chironomus spp. as standard test species for chronic Tier-1 derivation. Although protective in the majority of cases, the conservativeness of the recommended chronic Tier-1 RACs appears to be less than an order of magnitude for a relatively large proportion of insecticides when compared with their Tier-3 ETO-RACs. This may leave limited options for refinement of the chronic effect assessment using laboratory toxicity data for additional species. Integr Environ Assess Manag 2016;12:747–758. © 2015 SETAC