bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Conformational Study of Model Peptides Containing N‐Substituted 3‐Aminoazetidine‐3‐carboxylic Acids
Authors: Žukauskaitė Asta , Moretto Alessandro , Peggion Cristina , De Zotti Marta , Šačkus Algirdas , Formaggio Fernando , De Kimpe Norbert , Mangelinckx Sven 
Published: February 2014

AbstractModel peptides containing N‐substituted 3‐aminoazetidine‐3‐carboxylic acids have been synthesized to investigate the conformational features of these Cα‐tetrasubstituted amino acids. The target peptides were designed and prepared by classical synthetic methods in solution, exploiting the convenient N‐substituted 3‐azidoazetidine‐3‐carboxylic acids as precursors. The conformational preferences of the newly synthesized peptides were investigated in solution by IR and NMR spectroscopy. It was observed that the 3‐aminoazetidine‐3‐carboxylic acid moiety is likely a β‐turn inducer. In addition, an interesting main‐chain‐to‐side‐chain hydrogen bond that forms a six‐membered pseudo‐cycle was detected. It connects the nitrogen (acceptor) of the azetidine ring to the amide NH (donor) of the immediately following residue. This unexpected hydrogen bond increases the number of conformational options offered by N‐substituted 3‐aminoazetidine‐3‐carboxylic acids when designing foldamers with new and predictable 3D structures.
Synthesis of the Bioactive Benzochromenes Pulchrol and Pulchral, Metabolites of Bourreria pulchra
Authors: Killander Dan , Sterner Olov 
Published: February 2014

AbstractThe parasites Leshmania mexicana and Trypanosoma cruzi cause serious health problems, and few efficient treatments are available. Recently, the two benzochromenes pulchrol (1) and pulchral (2) were reported from the roots of Bourreria pulchra, and especially 1 but also 2 was found to be active towards the parasites. In this paper, we present a total synthesis of 1 and 2 to facilitate their biological evaluation. The synthesis is mild, short, and high yielding and suitable for a structure–activity relationship study.
Beyond need satisfaction: Empowering and accepting messages from third parties ineffectively restore trust and consequent reconciliation
Authors: Shnabel Nurit , Nadler Arie , Dovidio John F. 
Published: February 2014

AbstractAccording to the Needs‐Based Model, reconciliation requires the restoration of victims' sense of power and perpetrators' moral image, which can be achieved through the exchange of empowering and accepting messages. In two role‐playing experiments, we extended the model by examining the role of message source, the other conflict party versus a neutral third party, in facilitating reconciliation. Focusing on transgressions between apartment roommates, Study 1 found that regardless of message source, empowering messages restored victims' sense of power, and accepting messages restored perpetrators' moral image. Yet, messages from the other conflict party restored victims' and perpetrators' trust in each other more effectively than messages from third parties. Multiple mediation analyses revealed that both need satisfaction (restoring victims' sense of power and perpetrators' moral image) and trust building were critical for reconciliation. Replicating these findings in a context of transgressions between workplace colleagues, Study 2 further revealed that messages from third parties restored perpetrators' moral image only in the eyes of the third party (but not in the eyes of the victim), leading to a negative indirect effect on perpetrators' reconciliation tendencies. Theoretical implications for the modification of the Needs‐Based Model and practical implications for the limits of third parties' interventions to promote interpersonal reconciliation are discussed. Copyright © 2014 John Wiley & Sons, Ltd.
Acute toxicity of sodium bicarbonate, a major component of coal bed natural gas produced waters, to 13 aquatic species as defined in the laboratory
Authors: Harper David D. , Farag Aïda M. , Skaar Don 
Published: February 2014

Abstract

Water produced during coal bed natural gas (CBNG) extraction in the Powder River Structural Basin of Wyoming and Montana (USA) may contain concentrations of sodium bicarbonate (NaHCO3) of more than 3000 mg/L. The authors evaluated the acute toxicity of NaHCO3, also expressed as bicarbonate (HCO3−), to 13 aquatic organisms. Of the 13 species tested, 7 had a median lethal concentration (LC50) less than 2000 mg/L NaHCO3, or 1300 mg/L HCO3−. The most sensitive species were Ceriodaphnia dubia, freshwater mussels (Lampsilis siliquoidea), pallid sturgeon (Scaphirhynchus albus), and shovelnose sturgeon (Scaphirhynchus platorynchus). The respective LC50s were 989 mg/L, 1120 mg/L, 1249 mg/L, and 1430 mg/L NaHCO3, or 699 mg/L, 844 mg/L, 831 mg/L, and 1038 mg/L HCO3−. Age affected the sensitivity of fathead minnows, even within life stage. Two days posthatch, fathead minnows were more sensitive to NaHCO3 and HCO3− compared with 4-d-old fish, even though fish up to 14 d old are commonly used for toxicity evaluations. The authors recommend that ion toxicity exposures be conducted with organisms less than 24 h posthatch to ensure that experiments document the most sensitive stage of development. The results of the present study, along with historical and current research regarding the toxicity of bicarbonate, may be useful to establish regulatory standards for HCO3−. Environ Toxicol Chem 2014;33:525–531. © 2014 SETAC. This article is a US Government work and is in the public domain in the USA.
The chronic toxicity of sodium bicarbonate, a major component of coal bed natural gas produced waters
Authors: Farag Aïda M. , Harper David D. 
Published: February 2014

Abstract

Sodium bicarbonate (NaHCO3) is the principal salt in coal bed natural gas produced water from the Powder River Structural Basin, Wyoming, USA, and concentrations of up to 3000 mg NaHCO3/L have been documented at some locations. No adequate studies have been performed to assess the chronic effects of NaHCO3 exposure. The present study was initiated to investigate the chronic toxicity and define sublethal effects at the individual organism level to explain the mechanisms of NaHCO3 toxicity. Three chronic experiments were completed with fathead minnows (Pimephales promelas), 1 with white suckers (Catostomus commersoni), 1 with Ceriodaphnia dubia, and 1 with a freshwater mussel, (Lampsilis siliquoidea). The data demonstrated that approximately 500 mg NaHCO3/L to 1000 mg NaHCO3/L affected all species of experimental aquatic animals in chronic exposure conditions. Freshwater mussels were the least sensitive to NaHCO3 exposure, with a 10-d inhibition concentration that affects 20% of the sample population (IC20) of 952 mg NaHCO3/L. The IC20 for C. dubia was the smallest, at 359 mg NaHCO3/L. A significant decrease in sodium–potassium adenosine triphosphatase (Na+/K+ ATPase) together with the lack of growth effects suggests that Na+/K+ ATPase activity was shut down before the onset of death. Several histological anomalies, including increased incidence of necrotic cells, suggested that fish were adversely affected as a result of exposure to &gt;450 mg NaHCO3/L. Environ Toxicol Chem 2014;33:532–540. © 2014 SETAC. This article is a US Government work and is in the public domain in the USA.
Development of Ternary Cathodes Using MyCe1–x–yMnxO2–δ (M = La, Gd) as Catalysts for Oxygen Reduction Reactions
Authors: Liu L. , Zhao Z. , Zhang X. , Cui D. , Tu B. , Ou D. , Cheng M. 
Published: February 2014

AbstractMyCe1–x–yMnxO2–δ (M = La, Gd) oxides have been investigated as oxygen reduction catalysts for LSM–YSZ based ternary cathodes. MyCe1–x–yMnxO2–δ samples are characterized by X‐ray diffraction (XRD), temperature programmed reduction of H2 (H2‐TPR), and temperature programmed desorption of O2 (O2‐TPD). The results show that the incorporation of M (M = La, Gd) ions increases the solution limit of Mn in the solid solutions, which increases the amount of oxygen vacancies and promotes oxygen adsorption and dissociation processes. The ternary cathodes show much higher electrochemical performance than LSM–YSZ binary cathode, and greatly accelerate oxygen dissociative adsorption and diffusion of oxygen species. The MyCe1–x–yMnxO2–δ catalysts exhibit greatly high activity for oxygen reduction at intermediate temperature. The ternary cathodes have high stability and high resistance to CO2 at 600 °C.
Raman Microspectroscopy as a Useful Tool for In Situ and Operando Studies of Water Transport in Perfluorosulfonic Membranes for PEMFCs
Authors: Deabate S. , Huguet P. , Morin A. , Gebel G. , Lanteri Y. , Peng Z. , Sutor A.‐K. 
Published: February 2014

AbstractAn operating PEMFC for commercial use must be able to adapt to variations in power demands and operating conditions while maintaining near optimal performance. Current research shows that one of the main issues affecting power output, stability, and longevity is the quantity and distribution of water in the system. The last are strongly affected by the sorption and transport properties of the polymer electrolyte. Thus, the need for a fundamental understanding of water transport in the PEMFC membrane‐electrode assembly has motivated, over the past few years, the development of new operando diagnostic tools sensitive to the membrane hydration. Among these, the most recent technique is based on confocal Raman microspectroscopy. This tutorial review is devoted to the illustration of the basis of this method, with a particular focus on the Raman signal processing needed to obtain reliable through‐plane water concentration profiles across PFSA membranes. Then, the potential of in situ and operando μ‐Raman is highlighted by reviewing the few studies reported to date, completed by the most recent results obtained by our group. Finally, advantages and drawbacks of operando Raman microspectroscopy are shortly discussed.
Impact of manganese on primary hippocampal neurons from rodents
Authors: Daoust Alexia , Saoudi Yasmina , Brocard Jacques , Collomb Nora , Batandier Cécile , Bisbal Mariano , Salomé Murielle , Andrieux Annie , Bohic Sylvain , Barbier Emmanuel L. 
Published: February 2014

ABSTRACTManganese‐enhanced magnetic resonance imaging (MEMRI) is a powerful tool for in vivo tract tracing or functional imaging of the central nervous system. However Mn2+ may be toxic at high levels. In this study, we addressed the impact of Mn2+ on mouse hippocampal neurons (HN) and neuron‐like N2a cells in culture, using several approaches. Both HN and N2a cells not exposed to exogenous MnCl2 were shown by synchrotron X‐ray fluorescence to contain 5 mg/g Mn. Concentrations of Mn2+ leading to 50% lethality (LC50) after 24 h of incubation were much higher for N2a cells (863 mM) than for HN (90 mM). The distribution of Mn2+ in both cell types exposed to Mn2+ concentrations below LC50 was perinuclear whereas that in cells exposed to concentrations above LC50 was more diffuse, suggesting an overloading of cell storage/detoxification capacity. In addition, Mn2+ had a cell‐type and dose‐dependent impact on the total amount of intracellular P, Ca, Fe and Zn measured by synchrotron X‐ray fluorescence. For HN neurons, immunofluorescence studies revealed that concentrations of Mn2+ below LC50 shortened neuritic length and decreased mitochondria velocity after 24 h of incubation. Similar concentrations of Mn2+ also facilitated the opening of the mitochondrial permeability transition pore in isolated mitochondria from rat brains. The sensitivity of primary HN to Mn2+ demonstrated here supports their use as a relevant model to study Mn2+‐induced neurotoxicity. © 2014 Wiley Periodicals, Inc.
Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings
Authors: Eric Jones John , Chen Meng , Yu Qingsong 
Published: February 2014

ABSTRACTTo improve their corrosion resistance and thus long‐term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20–25 nm in thickness. Both direct current (DC) and radio‐frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH3/O2 plasma treatment to tailor the surface properties. X‐ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si‐ and C‐rich composition, and the O‐ and N‐contents on the surfaces were substantially increased after NH3/O2 plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH3/O2 plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 1363–1374, 2014.
Immunological response to bolus versus multiple injections of hylan G‐F 20 (Synvisc®) in a murine biocompatibility model
Authors: Markel David C. , Jackson Nancy M. , Esquivel Amanda O. , Ren Weiping , Flynn Jeffrey C. 
Published: February 2014

ABSTRACTLocal tissue reactivity to intra‐articular injections of hyaluronic acid hylan G‐F 20 (Synvisc®) has been described. We used a murine biocompatibility model to study the inflammatory response to Synvisc® after a single bolus injection versus the traditional three shot series of injections. Air pouches were established subcutaneously in BALB/c mice, which were injected with phosphate‐buffered saline (PBS), 5 mg ultra‐high molecular weight polyethylene particles (to simulate synthetic joint wear debris, positive control), 0.5 mL Synvisc® (one injection/week for three weeks, harvested 14 days after last injection), or 1.5 mL Synvisc® bolus (harvested either 14 or 28 days after last injection). Inflammatory gene expression and inflammation of air pouch tissue, and serum antibody titers to Synvisc® were determined. Inflammation was observed with all Synvisc® treatments relative to PBS (p < 0.01). However, the three injection series of Synvisc® resulted in significantly (p < 0.05) greater tumor necrosis factor‐alpha gene expression compared to both PBS and bolus single shot Synvisc® harvested after 14 or 28 days. While all Synvisc® treatments resulted in serum antibodies to Synvisc® (p < 0.02 compared to PBS control group), mice that received three injections of Synvisc® had higher levels than mice receiving a single injection (p < 0.01). These results demonstrate that a single bolus injection of Synvisc® led to less inflammation and a lower antibody response when compared to the three‐shot series of injections, supporting the current change in treatment from multiple injections to a single injection of Synvisc®. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 1375–1380, 2014.
Facile synthesis of ZnO nanorods grown on graphene sheets and its enhanced photocatalytic efficiency
Authors: Lv Rong , Wang Xitao , Lv Wei , Xu Yanli , Ge Yonghui , He Hui , Li Geng , Wu Xiaoqian , Li Xu , Li Qiang 
Published: February 2014

AbstractBACKGROUNDRecent advancements in nanoscale materials have focused on well‐designed nanocomposites that are highly oriented and organized. Three‐dimensional arrays consisting of one‐dimensional ZnO nanorods grown on reduced graphene oxide (RGO) sheets should be an efficient photocatalyst for photocatalytic hydrogen production from glycerol solution due to the increased adsorptivity of the reactant, extended light absorption range, and especially efficient charge transportation and separation.RESULTSIt was found that the calcination temperature of the ZnO seed layer had a significant influence on the morphology, surface structure, optical and electronic properties of ZnO/RGO nanocomposites. When the calcination temperature of the ZnO seed layer was 400 °C, ZnO nanorods grown on graphene sheets with C–O–Zn linkages can be achieved. This sample exhibited the highest photocatalytic H2 production rate.CONCLUSIONThe results of this study show that superior photocatalytic performance originates from the higher transfer rate of photo‐generated electrons from ZnO to RGO, and repressed recombination of the photoinduced hole–electron pairs of ZnO, which is closely related with the chemical interaction between ZnO and RGO and the concentration of Zn–O–C bonds. Moreover, the morphology of ZnO nanorods favors the directional transfer of electrons in ZnO. © 2014 Society of Chemical Industry
The ventral nerve cord in cephalocarida (Crustacea): New insights into the ground pattern of tetraconata
Authors: Stegner Martin E.J. , Brenneis Georg , Richter Stefan 
Published: February 2014

ABSTRACTCover illustration. The horseshoe shrimp Hutchinsoniella macracantha belongs to the ancient crustacean taxon of Cephalocarida. Its external morphology and neuroanatomy exhibit several plesiomorphic structures and patterns dating back to the ancestor of all Tetraconata. In this issue of the Journal of Morphology, Stegner and coauthors (pp. 269–294) studied the ventral nerve cord of adult Hutchinsoniella macracantha in detail, combining immunolabeling (tubulin, serotonin, RFamide, histamine) and nuclear stains with confocal laser microscopy, complemented by 3D‐reconstructions based on serial semithin sections. The cover image shows lateral 3D‐overviews of the cuticle (white in top row, semitransparent in second row), the gut (green, third row), and the ventral nerve cord (neurites and neuropil in yellow, somata in dark grey, bottom row). Different from most other crustaceans, also the limb‐less abdomen in Cephalocarida comprises segmental ganglia.
Interpreting Tourism at Olympic Sites: A Cross‐cultural Analysis of the Beijing Olympic Green
Authors: Brown Graham , Huang Songshan (Sam) 
Published: February 2014

AbstractAn examination is made of tourism at Olympic sites by reflective analyses of experiences gained at the Beijing Olympic Green. An account of experiences at the site, accompanied by photographs, was analysed through different cultural lenses to reveal distinctive characteristics of the setting and divergent interpretations of tourist behaviour. The findings enhance understanding of the role of Olympic sites as tourist attractions and the importance of photography as part of the tourist experience and as a research tool. The study demonstrates the utility of post‐experience interpretations when informed by relevant theoretical frameworks. Copyright © 2014 John Wiley & Sons, Ltd.
Survival and population growth of a free‐ranging elk population with a long history of exposure to chronic wasting disease
Authors: Monello Ryan J. , Powers Jenny G. , Hobbs N. Thompson , Spraker Terry R. , Watry Mary Kay , Wild Margaret A. 
Published: February 2014

ABSTRACTInvestigations of chronic wasting disease (CWD), a fatal, contagious prion disease of free‐ranging cervids, suggest the disease can cause long‐term population declines in deer (Odocoileus spp.). However, the implications of CWD for elk (Cervus elaphus nelsoni) populations are less certain. During 2008–2010, we used rectal biopsies and telemetry to observe disease transmission and survival in adult female elk from a high‐density herd in Rocky Mountain National Park (RMNP) that had been infected by CWD for over 25 years. We studied a cohort of 123 adult female elk that were determined to be free of CWD by rectal biopsy in 2008. Annual incidence of CWD was 0.08 [95% Bayesian credible interval (BCI) = 0.05, 0.12]. Annual survival probabilities of the cohort excluding harvest declined from 0.97 in 2008 (BCI = 0.93, 0.99) to 0.85 in 2010 (BCI = 0.75, 0.93). Declines in survival were attributed almost entirely to CWD; the proportion of radiocollared elk that died of CWD increased from 0.02 in 2008 (BCI = 0.00, 0.05) to 0.11 in 2010 (BCI = 0.04, 0.21). We attributed the increase to the time lag required for development of new CWD cases. We used survival rates of susceptible and infected elk to develop a projection matrix for a discrete time, female only model that estimated the intrinsic population growth rate (λ) of this elk herd to be 1.00 (BCI = 0.93, 1.05) using the prevalence of CWD (12.9%) and calf:cow ratios (24:100) observed during this study. Population declines were predicted to occur when prevalence of CWD exceeded 13% (BCI = 0, 35). However, this estimate was contingent on calf:cow ratios and harvest. Greater recruitment will offset some of the effects of CWD, whereas the inclusion of female harvest, which was excluded from this study, would likely result in lower λ values than those observed in this study. We conclude that CWD can exceed natural rates of mortality, reduce survival of adult females, and decrease population growth of elk herds. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Deposit chemistry and initial corrosion during biomass combustion – The influence of excess O2 and sulphate injection
Authors: Viklund P. , Kassman H. , Åmand L.‐E. 
Published: February 2014

Corrosion of superheater tubes is a serious problem during combustion of fuels with a high content of chlorine, such as waste and certain biomasses. The alkali chlorides are released to the flue gas and may condense on the heat exchanger tubes forming corrosive, chloride‐rich deposits. In this work the effect of ammonium sulphate ((NH4)2SO4) injection on gaseous alkali chlorides, deposit chemistry and initial corrosion attack of superheater tubes during biomass combustion have been investigated. The investigation was carried out at three different sulphate injection rates (reference, low and high) and at three air excess ratios (λ = 1.1, 1.2 and 1.4). Short‐term exposures of Sanicro 28 specimens, using temperature controlled probes, were used for deposit collection and to study the initial corrosion attack.The results showed reduced concentrations of potassium chloride in the flue gas when injecting ammonium sulphate and in particular in combination with high air excess ratios. A decrease of chlorine was also observed in the deposit, but the concentrations did not always correlate to the flue gas measurements. In particular, it was evident that a subsequent sulphation occurred on the tube surface at low air excess ratios. Metallography revealed that sulphation reactions on the tube surface, rather than in the flue gas, had a detrimental effect on the initial corrosion attack. As a consequence, the corrosion attack correlated more clearly to the KCl(g) concentration in the flue gas than the chlorine content in the deposit.
A Miscible and Adaptive Poly(methyl acrylate)/Polystyrene Blend Formed by Multiple‐Responsive Host–Guest Interactions
Authors: Ji Xiaofan , Chen Jianzhuang , Xue Min 
Published: February 2014

Polymer blends play a significant role in polymer science due to their new and unique properties compared with the individual polymer components. However, most polymer blends are immiscible and not adaptive to environmental stimuli. Here, an enhancement of the compatibility of an immiscible poly(methy acrylate)/polystyrene blend based on multiple‐responsive benzo‐21‐crown‐7/dialkylammoniumsalt host–guest interactions is made. Owing to the multi‐responsiveness and reversibility of benzo‐21‐crown‐7/dialkylammoniumsalt host–guest interactions, the polymer blend recovers its compatibility after being damaged by environmental factors, indicating its adaptiveness.
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