bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climate response to externally mixed black carbon as a function of altitude
Authors: Samset B. H. , Myhre G. 
Published: March 2015

AbstractThe climate response to the presence of black carbon (BC) aerosol at a given altitude in the atmosphere is investigated using a global circulation model. The vertical dependence of the efficiency with which BC exerts radiative forcing (RF) through the direct aerosol effect has previously been extensively studied. Here we use the Community Atmosphere Model version 4 atmospheric component of the National Center for Atmospheric Research Community Earth System model version 1.03 to calculate the three‐dimensional response to a BC layer inserted at various altitudes. Simulations have been performed both for fixed sea surface temperatures and using a slab ocean setup to include the surface temperature response. We investigate the vertical profiles of RF exerted per gram of externally mixed BC due to both the direct and semidirect aerosol effects. Associated changes in cloud cover, relative humidity, and precipitation are discussed. The precipitation response to BC is decomposed into a fast, stability‐related change and a slow, temperature‐driven component. We find that while the efficiency of BC to exert positive RF due to the direct effect strengthens with altitude, as in previous studies, it is strongly offset by a negative semidirect effect. The net radiative perturbation of BC at top of atmosphere is found to be positive everywhere below the tropopause and negative above. The global, annual mean precipitation response to BC, after equilibration of a slab ocean, is found to be positive between the surface and 900 hPa but negative at all other altitudes.
Evapotranspiration based on equilibrated relative humidity (ETRHEQ): Evaluation over the continental U.S.
Authors: Rigden Angela J. , Salvucci Guido D. 
Published: March 2015

AbstractA novel method of estimating evapotranspiration (ET), referred to as the ETRHEQ method, is further developed, validated, and applied across the U.S. from 1961 to 2010. The ETRHEQ method estimates the surface conductance to water vapor transport, which is the key rate‐limiting parameter of typical ET models, by choosing the surface conductance that minimizes the vertical variance of the calculated relative humidity profile averaged over the day. The ETRHEQ method, which was previously tested at five AmeriFlux sites, is modified for use at common weather stations and further validated at 20 AmeriFlux sites that span a wide range of climates and limiting factors. Averaged across all sites, the daily latent heat flux RMSE is ∼26 W·m−2 (or 15%). The method is applied across the U.S. at 305 weather stations and spatially interpolated using ANUSPLIN software. Gridded annual mean ETRHEQ ET estimates are compared with four data sets, including water balance‐derived ET, machine‐learning ET estimates based on FLUXNET data, North American Land Data Assimilation System project phase 2 ET, and a benchmark product that integrates 14 global ET data sets, with RMSEs ranging from 8.7 to 12.5 cm·yr−1. The ETRHEQ method relies only on data measured at weather stations, an estimate of vegetation height derived from land cover maps, and an estimate of soil thermal inertia. These data requirements allow it to have greater spatial coverage than direct measurements, greater historical coverage than satellite methods, significantly less parameter specification than most land surface models, and no requirement for calibration.
Volume of Martian midlatitude glaciers from radar observations and ice flow modeling
Authors: Karlsson N. B. , Schmidt L. S. , Hvidberg C. S. 
Published: March 2015

AbstractNumerous glacier‐like forms have been identified in the midlatitudes of Mars, and within recent years the acquisition of radar sounding data has revealed that the features are chiefly composed of water ice. Here we use radar observations in combination with ice flow models and inverse methods to calculate the volume of ice present at the midlatitudes of Mars. In order to obtain ice thicknesses, we infer the yield stress of the ice deposits, and we find that they are consistently lower than those of most terrestrial glaciers. We estimate the present ice volume of lobate debris aprons (identified by Levy et al. (2014)) on Mars to correspond to 1.55 · 105 km3 with an uncertainty of 25%. This corresponds to a global ice cover of 1.1m. Thus, the water ice found at midlatitudes is an important water reservoir, and an important part of the global surface ice budget.
Estimates of Lagrangian transport by surface gravity wave groups: The effects of finite depth and directionality
Authors: van den Bremer T. S. , Taylor P. H. 
Published: March 2015

AbstractTwo physical phenomena drive the Lagrangian trajectories of neutrally buoyant particles underneath surface gravity wave groups: the Stokes drift results in a net displacement of particles in the direction of propagation of the group, whereas the Eulerian return flow transports such particles in the opposite direction. Generally, the Stokes drift is the larger of the two near the surface, whereas the effects of the return flow dominate at depth. A transition depth can be defined that separates the two regimes. Using a multiple‐scales expansion, we provide leading‐order estimates of the forward transport, the backward transport, and the transition depth for realistic sea states. We consider the effects of both finite depth and the directionally spread nature of the waves on our estimates. We show that from the perspective of the return flow, almost all seas are of finite depth. In fact, many seas can be shown to be “shallow” from the perspective of the return flow with little variation of this flow with depth. Furthermore, even small degrees of directional spreading can considerably reduce the magnitude of the return flow and its transport.
A Synthetic Erectile Optogenetic Stimulator Enabling Blue‐Light‐Inducible Penile Erection
Authors: Kim Taeuk , Folcher Marc , Baba Marie Doaud‐El , Fussenegger Martin 
Published: March 2015

AbstractPrecise spatiotemporal control of physiological processes by optogenetic devices inspired by synthetic biology may provide novel treatment opportunities for gene‐ and cell‐based therapies. An erectile optogenetic stimulator (EROS), a synthetic designer guanylate cyclase producing a blue‐light‐inducible surge of the second messenger cyclic guanosine monophosphate (cGMP) in mammalian cells, enabled blue‐light‐dependent penile erection associated with occasional ejaculation after illumination of EROS‐transfected corpus cavernosum in male rats. Photostimulated short‐circuiting of complex psychological, neural, vascular, and endocrine factors to stimulate penile erection in the absence of sexual arousal may foster novel advances in the treatment of erectile dysfunction.
Preparation and properties of polyurethane‐modified epoxy cured in different simulated gravity environments
Authors: Li Defeng , Wang Youshan , Liu Yuyan , Xie Zhimin , Wang Lei , Tan Huifeng 
Published: March 2015

ABSTRACTGreat attention has been paid to the composites with interpenetrating polymer networks (IPNs) because of their special performance. However, the influence of sedimentation and convection from different gravity environments on the formation of IPNs and the properties of IPNs blends has received little attention. To understand their influence, environments with different gravity accelerations of 0g, 1g, and 2g were simulated with a superconducting magnet, and tests, including differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), coefficient of thermal expansion (CTE), scanning electron microscopy, and three‐point bending, of the IPNs blends cured in different gravity environments were conducted and analyzed. Fourier transform infrared spectroscopy, DSC, and DMA proved the formation of IPNs during the reaction between the polyurethane prepolymer (PUP) and epoxy resin (E51). The curves of DSC also certified the differences in the curing degree between the different parts along the direction of gravity of a sample. With the increase of mass fraction of PUP, the change trends of the storage modulus presented a linear decrease when samples cured in microgravity environment, but presented a parabolic trend when samples were cured in terrestrial environment. The damping properties of samples cured in simulated microgravity environments are better than those cured in terrestrial environment. With the increase in the simulated acceleration of gravity, the diameter of dispersed phase in a sea‐island structure increased, but their number decreased and the bending stress and CTE of the IPN blends all decreased. These results show the formation of IPNs was affected by different gravity values, and the thermal and mechanical properties of the IPN composites were influenced by the changed IPN components. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42063.
Preparation of grafted cationic polymer/silver chloride modified cellulose fibers and their antibacterial properties
Authors: Chen Xiaoqin , Hu Bojian , Xing Xiaodong , Liu Zuliang , Zuo Yan , Xiang Qian 
Published: March 2015

ABSTRACTIn this article, we present a simple method for synthesizing antibacterial cellulose fibers that were modified with a cationic polymer and immobilized silver chloride (AgCl) particles. Relatively simple techniques of graft polymerization and onsite precipitation were used to fabricate the composites. Scanning electron microscopy images, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, and energy‐dispersive X‐ray spectroscopy confirmed the immobilization of the AgCl particles. The observed inhibition zone of the immobilized AgCl particle composites indicated that the biocidal silver ions were released from the composites in aqueous solution. Compared with cationic‐polymer‐grafted cellulose fibers or AgCl alone, the cationic polymer/AgCl composites showed excellent antibacterial activity against Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42092.
Electric‐field response behaviors of chitosan/barium titanate composite hydrogel elastomers
Authors: Gao Ling‐Xiang , Chen Jian‐Li , Han Xue‐Wu , Zhang Jian‐Lan , Yan Shu‐Xian 
Published: March 2015

ABSTRACTChitosan/barium titanate (BaTiO3) composite hydrogel elastomers were prepared in the presence or absence of an applied direct‐current (dc) electric field. Scanning electron microscopy was used to observe the microstructure of the elastomers and the dispersion of particles in it. Tests of the storage moduli (Gs) of the elastomers were investigated with a dynamic mechanical analyzer. On this basis, the G increment and increment sensitivity were explored. The results show that the particles were sequentially dispersed, and the values of the G values for the elastomer were higher under an external applied dc electric field; this indicated that the composite elastomers exhibited excellent electric field response. Furthermore, the electric‐field response of the composite elastomers changed with the particle concentration, and the maximum response occurred when the mass fraction of BaTiO3 was 2.0%. The G value of the composite elastomer with a BaTiO3 weight percentage of 2.0 increased with increasing electric field; this revealed that the composite elastomer had a positive electric field response. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42094.
Investigation of new composite materials based on activated EPDM rubber waste particles by liquid polymers
Authors: Lepadatu Ana‐Maria , Asaftei Simona , Vennemann Norbert 
Published: March 2015

ABSTRACTDespite of the variety of existing techniques, there is still a continuous demand in the development of more efficient recycling technologies, for economic and environmental reasons. A new approach for recycling EPDM rubber waste has been recently introduced utilizing a solvent free activation process by addition of liquid polymers (LP). The present study investigates the influence of the content and varying types of activated rubber waste particles (RWP‐LP) in new composites. By varying the proportion of RWP‐LP in the range from 25 up to 75 v/v % information about optimized compositions of new compounds were obtained. It was found that the ratio and type of RWP‐LP induce significant differences in terms of cure characteristics, mechanical properties, crosslink density and morphology. Promising results with high potential application for the production of seal and sealing systems on the industrial scale were obtained by using up to 50 v/v % of RWP‐LP with low ethylene amount. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42097.
Morphology and thermal degradation studies of melt‐mixed PLA/PHBV biodegradable polymer blend nanocomposites with TiO2 as filler
Authors: Mofokeng Julia P. , Luyt Adriaan S. 
Published: March 2015

ABSTRACTThe morphology and thermal stability of melt‐mixed poly(lactic acid) (PLA)/poly(hydroxybutyrate‐co‐valerate) (PHBV) blends and nanocomposites with small amounts of TiO2 nanoparticles were investigated. PLA/PHBV at 50/50 w/w formed a co‐continuous structure, and most of the TiO2 nanoparticles were well dispersed in the PLA phase and on the interface between PLA and PHBV, with a small number of large agglomerates in the PHBV phase. Thermogravimetric analysis (TGA) and TGA–Fourier‐transform infrared spectroscopy was used to study the thermal stability and degradation behavior of the two polymers, their blends, and nanocomposites. The thermal stability of PHBV was improved through blending with PLA, whereas that of the PLA was reduced through blending with PHBV, and the presence of TiO2 nanoparticles seemingly improved the thermal stability of both polymers in the blend. However, the degradation kinetics results revealed that the nanoparticles could catalyze the degradation process and/or retard the volatilization of the degradation products, depending on their localization and their interaction with the polymer in question. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42138.
Niche processes and conservation implications of fish community assembly in a rice irrigation system
Authors: Ohira Mitsuru , Tsunoda Hiroshi , Nishida Kazuya , Mitsuo Yoshito , Senga Yutaro 
Published: March 2015

Abstract

Riparian fluvial systems are used for the irrigation of rice. This practice has led to an increasing need to conserve biodiversity of these riparian systems against intensification of rice　irrigation systems. This study examined the underlying processes that structure fish community assemblages in a traditional rice irrigation system and how these processes might inform conservation programmes.
Sampling was conducted at 26 reaches of a permanent irrigation channel in September and December 2007 and May 2008. The relative roles of niche versus dispersal processes were determined by examining species richness across the local environment, such as habitat complexity (diversity of depth and velocity) and size (volume of water) or proximity from the river as potential source of species, and deterministic versus stochastic processes. Non‐random or random patterns of species co‐occurrence were also compared across the sites.
Each site's species richness was mainly associated with habitat complexity and size, but not proximity to the river. Also, species co‐occurred non‐randomly in segregated patterns. Therefore, the fish community was deterministically structured by niche processes and local extinction, but not by stochastic and external immigration processes. In addition, the observed relative abundance distributions primarily fitted a log–normal distribution, indicating a ‘low stress’ condition for the fish community.
To enhance co‐existence of fish species, high conservation priority should be given to local factors such as hydraulic complexity and volume of water at reach scale in the rice irrigation system. Fish species preferring slow and shallow environments co‐occurred less frequently among reaches, demonstrating the need to conserving hydraulic variability. The effectiveness of local factors and deterministic patterns is thought to derive from stable water flow and high internal and external connectivity, which in turn would safeguard the processes that structure fish community assemblages. Such hydrological connectivity might be the key for conservation in intensified rice‐farming landscapes. Copyright © 2015 John Wiley & Sons, Ltd.
Experimental Tests of Risk Ladders in the Elicitation of Perceived Likelihood
Authors: Persoskie Alexander , Downs Julie S. 
Published: March 2015

AbstractRisk ladders have the potential to improve numeric judgments of low‐likelihood events by providing information about the likelihoods of comparison risks, thereby letting respondents make risk estimates “in context.” However, to date this tool has been studied systematically only in communication of risk, not in elicitation of perceived likelihoods. In three studies, we evaluated the benefits of risk ladders on the consistency, validity, and mean‐level accuracy of elicited likelihood judgments. When estimates for low‐likelihood hazards were elicited using different numeric response scales (e.g., “1 in x” and “x in 100,000”), scale type had a strong effect on the magnitudes of the elicited estimates, and viewing a risk ladder (Experiment 1) or comparison risks (Experiments 2 and 3) did not attenuate this effect of scale type. Similarly, we found no evidence that risk ladders or comparison risks improved the convergent validity of numeric estimates, as measured using correlations with risk ratings made on alternative scale types. Finally, viewing comparison risks tended to reduce gross overestimation of rare events, with relatively less change in estimates for mid‐likelihood and high‐likelihood hazards. This suggests that comparison risks can spread responses to cover a wider range of values but do not ameliorate scale effects. In the elicitation of numeric risk estimates, how you ask matters, even if you let people make estimates “in context” through the use of comparative risk information. Copyright © 2015 John Wiley & Sons, Ltd.
X‐ray structure analysis reveals β‐turn mimicry by N‐amino‐imidazolidin‐2‐ones†
Authors: Doan Ngoc‐Duc , Lubell William D. 
Published: March 2015

ABSTRACT:The conformation of the N‐amino‐imidazolidin‐2‐one (Aid) peptidomimetic was investigated using NMR spectroscopy and X‐ray crystallography. In solution, the tetrapeptide model p‐bromobenzoyl‐Aid‐l‐Phe‐N′‐iso‐propylamide (1) exhibited shielded and solvent exposed amide protons indicative of a turn conformation. In the crystal lattice of 1, four turn conformers were present in the unit cell differing primarily by the ring puckering of the Aid residue. Two pairs of β‐turn conformers were observed each possessing an intramolecular ten‐member hydrogen bond between the benzamide carbonyl and iso‐propylamine NH moieties. The pairs had types II and II′ β‐turn geometry that differed slightly about the ϕ and ψ torsion angles. Moreover, the X‐ray analysis of 1 has been compared with that of the related unsaturated N‐amino‐imidazolin‐2‐one (Nai) analogs indicating the influences of ring flattening and substituents on conformation. Insertion of the preorganized Aid structure into biologically active peptides has thus been shown to offer a potentially valuable means for exploring the importance of turn geometry for activity, particularly in drug discovery. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 629–635, 2015.
Coupling limonene formation and oxyfunctionalization by mixed‐culture resting cell fermentation
Authors: Willrodt Christian , Hoschek Anna , Bühler Bruno , Schmid Andreas , Julsing Mattijs K. 
Published: March 2015

ABSTRACTMetabolic engineering strategies mark a milestone for the fermentative production of bulk and fine chemicals. Yet, toxic products and volatile reaction intermediates with low solubilities remain challenging. Prominent examples are artificial multistep pathways like the production of perillyl acetate (POHAc) from glucose via limonene. For POHAc, these limitations can be overcome by mixed‐culture fermentations. A limonene biosynthesis pathway and cytochrome P450 153A6 (CYP153A6) as regioselective hydroxylase are used in two distinct recombinant E. coli. POHAc formation from glucose in one recombinant cell was hindered by ineffective coupling of limonene synthesis and low rates of oxyfunctionalization. The optimization of P450 gene expression led to the formation of 6.20 ± 0.06 mg gcdw−1 POHAc in a biphasic batch cultivation with glucose as sole carbon and energy source. Increasing the spatial proximity between limonene synthase and CYP153A6 by a genetic fusion of both enzymes changed the molar limonene/POHAc ratio from 3.2 to 1.6. Spatial separation of limonene biosynthesis from its oxyfunctionalization improved POHAc concentration 3.3‐fold to 21.7 mg L−1 as compared to a biphasic fermentation. Mixed‐cultures of E. coli BL21 (DE3) containing the limonene biosynthesis pathway and E. coli MG1655 harboring either CYP153A6, or alternatively a cymene monooxygenase, showed POHAc formation rates of 0.06 or 0.11 U gcdw−1, respectively. This concept provides a novel framework for fermentative syntheses involving toxic, volatile, or barely soluble compounds or pathway intermediates. Biotechnol. Bioeng. 2015;112: 1738–1750. © 2015 Wiley Periodicals, Inc.
Determinants of improved survival after oesophagectomy for cancer
Authors: Talsma A K , Damhuis R A M , Steyerberg E W , Rosman C , van Lanschot J J B , Wijnhoven B P L 
Published: March 2015

Abstract

Background
Survival after oesophagectomy for cancer seems to be improving. This study aimed to identify the most important contributors to this change.

Methods
Patients who underwent oesophagectomy from 1999 to 2010 were extracted from the Netherlands Cancer Registry. Four time periods were compared: 1999–2001 (period 1), 2002–2004 (period 2), 2005–2007 (period 3) and 2008–2010 (period 4). Hospital type, tumour location, tumour type, tumour differentiation, neoadjuvant therapy, operation type, (y)pT category, involvement of surgical resection margins, number of removed lymph nodes and number of involved lymph nodes were investigated in relation to trends in survival using multivariable analysis.

Results
A total of 4382 patients were identified. Two-year overall survival rates improved from 49·3 per cent in period 1 to 58·4, 56·2 and 61·0 per cent in periods 2, 3 and 4 respectively (P &lt; 0·001). Multivariable survival analysis revealed that the improvement in survival between periods 3 and 4 was related to the introduction of neoadjuvant therapy. The improvement in survival between periods 1 and 2 could not be explained completely by the factors studied. The number of examined lymph nodes increased, especially between periods 2 and 3, but this increase was not associated with the improvement in survival.

Conclusion
The observed increase in long-term survival after surgery for oesophageal cancer between 1999 and 2010 in the Netherlands is difficult to explain fully, although the recent increase seems to be partly attributable to the introduction of neoadjuvant therapy.