bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐yield production of recombinant CRM197, a non‐toxic mutant of diphtheria toxin, in the periplasm of Escherichia coli
Authors: Goffin Philippe , Dewerchin Marianne , De Rop Philippe , Blais Normand , Dehottay Philippe 
Published: April 2017

AbstractA high cell density fed‐batch process was developed for production of recombinant CRM197, a non‐toxic mutant of diphtheria toxin widely used as a carrier in polysaccharide‐protein conjugate vaccines. Fully soluble recombinant CRM197 was obtained in high yields and with an authentic N‐terminus, by targeting the protein to the periplasm of Escherichia coli using the Signal Recognition Particle (SRP)‐dependent signal sequence of FlgI. Response Surface Methodology (RSM) was used to optimize the set‐points of key process parameters (pH and feed rate at induction). Optimal production of periplasmic CRM197 was found at a slightly basic pH (7.5). The feed rate during induction was positively correlated with the accumulation of unprocessed cytoplasmic CRM197, consistent with limited capacity of the SRP secretion pathway. Decreasing the feed rate to align the protein synthesis rate with the secretion capacity, resulted in minimal production of cytoplasmic CRM197. Besides, the host background was found critical for production of periplasmic CRM197: B834(DE3) was the highest producer (>3 g/L), while BLR(DE3) produced one third less CRM197, and very low yields (290 mg/L) were obtained with HMS174(DE3). The optimized process is robust and linearly scalable, and represents a 20‐fold yield improvement compared to a process based on Corynebacterium diphtheriae.
A biomimetic hydrogel functionalized with adipose ECM components as a microenvironment for the 3D culture of human and murine adipocytes
Authors: Louis Fiona , Pannetier Pauline , Souguir Zied , Le Cerf Didier , Valet Philippe , Vannier Jean‐Pierre , Vidal Guillaume , Demange Elise 
Published: April 2017

ABSTRACTThe lack of relevant in vitro models for adipose tissue makes necessary the development of a more physiological environment providing spatial and chemical cues for the effective maturation of adipocytes. We developed a biofunctionalized hydrogel with components of adipose extracellular matrix: collagen I, collagen VI, and the cell binding domain of fibronectin and we compared it to usual 2D cultures on plastic plates. This scaffold allowed 3D culture of mature adipocytes from the preadipocytes cell lines 3T3‐L1 and 3T3‐F442A, as well as primary Human White Preadipocytes (HWP), acquiring in vivo‐like organization, with spheroid shaped adipocytes forming multicellular aggregates. The size of these aggregates increased with time up to 120 μm in diameter after 4 weeks of maturation, with good viability. Significantly higher lipogenic activity (up to 20‐fold at day 28 for HWP cultures) and differentiation rates were also observed compared to 2D. Gene expression analyses highlighted earlier differentiation and complete maturation of 3D HWP compared to 2D, reinforced by the expression of Perilipin protein after 21 days of nutrition. This increase in adipocytes phenotypic and genotypic markers made this scaffold‐driven culture as a robust adipose 3D model. Retinoic acid inhibition of lipogenesis in HWP or isoprenalin and caffeine induction of lipolysis performed on mouse 3T3‐F442A cells, showed higher doses of molecules than typically used in 2D, underlying the physiologic relevance of this 3D culture system. Biotechnol. Bioeng. 2017;114: 1813–1824. © 2017 Wiley Periodicals, Inc.
Shortened dental arch as a solution for maxillary sinus proximity in dental implant restoration
Authors: Abdulghani Ashraf Sidig , Elhag Salma Babiker 
Published: April 2017

Key Clinical MessageThis case report demonstrates the benefit of using the shortened dental arch (SDA) design for a comprehensive implant‐supported restoration and the avoidance of the complexities of implant placement near the maxillary sinus. The SDA concept as a treatment option is encouraging in terms of function, patient satisfaction, and cost‐effectiveness.
In Vivo Synthesis of Polyhydroxylated Compounds from a “Hidden Reservoir” of Toxic Aldehyde Species
Authors: Bayer Thomas , Milker Sofia , Wiesinger Thomas , Winkler Margit , Mihovilovic Marko D. , Rudroff Florian 
Published: April 2017

AbstractSynthetic enzyme cascades in living cells often lack efficiency owing to the formation of byproducts by endogenous enzymes or toxicity of the cascade intermediates. Highly reactive aldehyde species can trigger a metabolic stress response, and this leads to undesired side reactions and decreased yields. Owing to the metabolic background of Escherichia coli (E. coli), aldehydes may be irreversibly oxidized to carboxylic acids or reduced to the corresponding alcohols. Herein, we applied an approach to equilibrate the aldehyde concentration in vivo. We oxidized primary alcohols to the corresponding aldehydes by AlkJ, an alcohol dehydrogenase from Pseudomonas putida. Introduction of a carboxylic acid reductase from Nocardia iowensis allowed the target compound to be retrieved from the carboxylate sink. Further reduction of the aldehydes to alcohols by endogenous E. coli enzymes completed the equilibration between alcohols, aldehydes, and carboxylic acids. Thus, the aldehyde concentrations remained below nonviable concentrations. We demonstrated the concept on several primary alcohols, which reached the redox equilibrium within 6 h and persisted up to 24 h. Subsequent combination with a dihydroxyacetone‐dependent aldolase (Fsa1‐A129S, E. coli) demonstrated that the reactive aldehyde species were freely available and gave the aldol product, (3S,4R)‐1,3,4‐trihydroxy‐5‐phenylpentan‐2‐one, in 70 % yield within short reaction times.
Unprecedented Variety of Outcomes in the Oxygenation of Dinuclear Alkylzinc Derivatives of an N,N‐Coupled Bis(β‐diketimine)
Authors: Pietrzak Tomasz , Korzyński Maciej Damian , Justyniak Iwona , Zelga Karolina , Kornowicz Arkadiusz , Ochal Zbigniew , Lewiński Janusz 
Published: April 2017

AbstractReactions between O2 and organometallics with non‐redox‐active metal centers have received continuous interest for over 150 years, although significant uncertainties concerning the character and details of the actual mechanism of these reactions persist. Harnessing dinuclear three‐coordinate alkylzinc derivatives of an N,N‐coupled bis(β‐diketimine) proligand (LH2) as a model system, we demonstrate for the first time that a slight modification of the reaction conditions might have a dramatic influence on the oxygenation reaction outcomes, leading to an unprecedented variety of products originating from a single reaction system, that is, partially and fully oxygenated zinc alkoxides, zinc alkylperoxides, and zinc hydroxide compounds. Our studies indicate that accessibility of the three‐coordinate zinc center by the O2 molecule, coupled with the lower reactivity of Zn‐Me vs. Zn‐Et units towards dioxygen, are key factors in the oxygenation process, providing a novel tetranuclear methyl(methoxy)zinc {[L][ZnMe][Zn(μ‐OMe]}2 and zinc ethoxide {[L][Zn(μ‐OEt)]2}2. Remarkably, oxygenation of three‐coordinate alkylzinc [L][ZnR]2 complexes at ambient temperature afforded a unique hydroxide {[L][Zn(μ‐OH)]2}2. Oxygenation of the [L][ZnEt]2 complex in the presence of 4‐methylpyridine (py‐Me) at low temperature led to the isolation of a dinuclear zinc ethylperoxide [L][Zn(OOEt)(py‐Me)]2, which nicely substantiates the intermediacy of an unstable zinc alkylperoxide in the formation of the subsequent zinc alkoxide and hydroxide compounds. Finally, our investigations provide compelling evidence that a non‐redox‐active metal center plays a crucial role in the oxygenation process through assisting in single‐electron transfer from an M−C bond to an O2 molecule. Although the oxygenation of zinc alkyls occurs by radical pathways, the reported results stand in clear contradiction to the widely accepted free‐radical chain mechanism.
Diphenylphosphine‐Oxide‐Fused and Diphenylphosphine‐Fused Porphyrins: Synthesis, Tunable Electronic Properties, and Formation of Cofacial Dimers
Authors: Fujimoto Keisuke , Kasuga Yuko , Fukui Norihito , Osuka Atsuhiro 
Published: April 2017

AbstractDiphenylphosphine‐oxide‐fused NiII porphyrin 8 was synthesized from 3,5,7‐trichloroporphyrin 5 via a reaction sequence of nucleophilic aromatic substitution with lithium diphenylphosphide, oxidation with H2O2, and palladium‐catalyzed intramolecular cyclization. Reduction of 8 with HSiCl3 gave diphenylphosphine‐fused NiII porphyrin 9. The embedded P=O and P moieties serve as a strong electron‐accepting and electron‐donating group to perturb the optical and electrochemical properties of the NiII porphyrin. NiII porphyrin 9 is diamagnetic with a low‐spin NiII center in solution but becomes paramagnetic with a five‐coordinated NiII center with high‐spin (S=1) state in the solid state. Diphenylphosphine‐oxide‐fused ZnII porphyrin 10 was also synthesized and shown to form a face‐to‐face dimer with mutual O‐Zn bonds in the crystal and in nonpolar and moderately polar solvents. The dimerization of 10 in CDCl3 has been revealed to be an entropy‐driven process with a large entropy gain (ΔSD=207 J K−1 mol−1).
Managing critical success factors for IS implementation: A stakeholder engagement and control perspective
Authors: Ahmed Zafor , Kumar Uma , Kumar Vinod 
Published: April 2017

AbstractEnterprise information systems (IS) implementation is often part of an organization's strategic IT initiatives and requires a large investment of organizational resources, yet may fail due to inadequate management of critical success factors (CSF). Using a revelatory case study of a multi‐partner COTS implementation process by a large Canadian government organization, this research investigates successful management of CSF through optimal stakeholder engagement and a balancing of control configurations. This research identifies four distinct project orientations related to stakeholder engagements—strategic, responsibility, harmony, and persuasion—that can be of significant value in managing CSF and other challenges during implementation and post‐implementation phases. In addition to the identification of a need for control balancing in a multi‐partner IS implementation, three key drivers responsible for triggering control balancing are identified: (a) shared understanding, (b) negative anticipation, and (c) deviation of expectations. Copyright © 2017 ASAC. Published by John Wiley & Sons, Ltd.
Wood sawdust and sewage sludge pyrolysis chars for CO2 adsorption using a magnetic suspension balance
Authors: Nascimento Paula F. P. , Sousa João F. , Oliveira Jackson A. , Possa Rosangela D. , Santos Luciene S. , Carvalho Fabíola C. , Ruiz Juan A. C. , Pedroza Marcelo M. , Bezerra Márcio B. D. 
Published: April 2017

AbstractIn view of global warming caused by the uncontrolled emissions of CO2 to the environment, there is a great need to develop methods able to eliminate this pollutant. Apart from establishing new techniques, the exploration of new materials with high separation performance and low cost are of importance. This work aims to treat carbon‐metals‐rich chars originated from the fast pyrolysis of sewage sludge and wood sawdust to be used as CO2 adsorbents. The samples were washed with ethanol and dichloromethane before their physical and chemical activation to remove impregnated bio‐oil. For the chemical activation, potassium hydroxide and hydrochloric acid were used as agents. The samples were analyzed via BET, TGA, XRD, and XRF. The results were used to investigate the role played by ethanol or dichloromethane and the effect of the activation on the properties of the materials such as specific surface area, total specific pore volume, and average pore size. CO2 isotherms were obtained experimentally at 25 °C using a magnetic suspension balance and the data was used to estimate Langmuir and Freundlich isotherm parameters. After chemical treatment, the sewage sludge char specific surface area increased 11 times and had an adsorptive capacity of 1.32 × 10−3 mol/g. The wood sawdust char specific surface area increased 90 times and had an adsorptive capacity of 3.73 × 10−3 mol/g. Desorption was carried out from 5 × 105 to 1 × 105 Pa at 37 °C and the efficiencies were 89.0 and 84.4 % for the sewage sludge and wood sawdust, respectively.
Adaptive unified continuum FEM modeling of a 3D FSI benchmark problem
Authors: Jansson Johan , Degirmenci Niyazi Cem , Hoffman Johan 
Published: April 2017

AbstractIn this paper, we address a 3D fluid‐structure interaction benchmark problem that represents important characteristics of biomedical modeling. We present a goal‐oriented adaptive finite element methodology for incompressible fluid‐structure interaction based on a streamline diffusion–type stabilization of the balance equations for mass and momentum for the entire continuum in the domain, which is implemented in the Unicorn/FEniCS software framework. A phase marker function and its corresponding transport equation are introduced to select the constitutive law, where the mesh tracks the discontinuous fluid‐structure interface. This results in a unified simulation method for fluids and structures. We present detailed results for the benchmark problem compared with experiments, together with a mesh convergence study.
A New Fabrication Method for Single‐Layer Nanosheets by Silver‐Assisted Exfoliation
Authors: Ganter Pirmin , Ziegler Christian , Friedrichs Anne T. , Duppel Viola , Scheu Christina , Lotsch Bettina V. 
Published: April 2017

AbstractThe discovery of 2D forms of matter, pioneered by graphene, has not only triggered new insights into fundamental physics but also pushed the limits of miniaturization. To process nanosheets into ultrathin functional devices, the development of scalable exfoliation routes is of key interest. Here, we demonstrate for the first time a mild, yet highly effective silver‐ion‐based exfoliation route for layered transition metal oxides. Single layer transition metal oxide nanosheets were obtained by applying silver ion exchange and subsequent treatment of the silver‐intercalated phases with an aqueous suspension containing organic iodides. This generic exfoliation route can be widely applied also to acid‐sensitive materials and allows the modification of the nanosheets with non‐conventional organic ligands, which owing to their chemical functionality may be used to tailor the optoelectronic and surface properties of the nanosheet–ligand hybrid.
Dispersal and extrapolation on the accuracy of temporal predictions from distribution models for the Darwin's frog
Authors: Uribe‐Rivera David E. , Soto‐Azat Claudio , Valenzuela‐Sánchez Andrés , Bizama Gustavo , Simonetti Javier A. , Pliscoff Patricio 
Published: April 2017

AbstractClimate change is a major threat to biodiversity; the development of models that reliably predict its effects on species distributions is a priority for conservation biogeography. Two of the main issues for accurate temporal predictions from Species Distribution Models (SDM) are model extrapolation and unrealistic dispersal scenarios. We assessed the consequences of these issues on the accuracy of climate‐driven SDM predictions for the dispersal‐limited Darwin's frog Rhinoderma darwinii in South America. We calibrated models using historical data (1950–1975) and projected them across 40 yr to predict distribution under current climatic conditions, assessing predictive accuracy through the area under the ROC curve (AUC) and True Skill Statistics (TSS), contrasting binary model predictions against temporal‐independent validation data set (i.e., current presences/absences). To assess the effects of incorporating dispersal processes we compared the predictive accuracy of dispersal constrained models with no dispersal limited SDMs; and to assess the effects of model extrapolation on the predictive accuracy of SDMs, we compared this between extrapolated and no extrapolated areas. The incorporation of dispersal processes enhanced predictive accuracy, mainly due to a decrease in the false presence rate of model predictions, which is consistent with discrimination of suitable but inaccessible habitat. This also had consequences on range size changes over time, which is the most used proxy for extinction risk from climate change. The area of current climatic conditions that was absent in the baseline conditions (i.e., extrapolated areas) represents 39% of the study area, leading to a significant decrease in predictive accuracy of model predictions for those areas. Our results highlight (1) incorporating dispersal processes can improve predictive accuracy of temporal transference of SDMs and reduce uncertainties of extinction risk assessments from global change; (2) as geographical areas subjected to novel climates are expected to arise, they must be reported as they show less accurate predictions under future climate scenarios. Consequently, environmental extrapolation and dispersal processes should be explicitly incorporated to report and reduce uncertainties in temporal predictions of SDMs, respectively. Doing so, we expect to improve the reliability of the information we provide for conservation decision makers under future climate change scenarios.
Fire‐mediated foraging tradeoffs in white‐tailed deer
Authors: Cherry Michael J. , Warren Robert J. , Conner L. Mike 
Published: April 2017

AbstractPredation risk can induce individual prey to express behavioral, physiological, and morphological traits that can influence population‐level processes. Maternal care is an intuitive link between predator‐mediated traits of individuals and population‐level processes because maternal investment can decrease with predation risk, and often influences processes such as neonatal growth, survival, and recruitment. During fawn‐rearing, many ungulate species restrict space use to a fraction of their home range. Selection of and within these areas can influence the quality of concealment cover for fawns and forage availability during early lactation which is the peak of maternal investment. Fire influences the distribution of food resources and cover for prey and their predators. In frequently burned systems, ungulates typically move into recently burned areas to exploit increased forage quality and detection of predators that use cover to stalk their prey. We investigated the effects of time since fire on the selection of and within fawn‐rearing areas and foraging behavior in white‐tailed deer in a frequently burned pine savanna. White‐tailed deer selected woodlands with greater time since fire and avoided recently burned areas, likely sacrificing forage quality for concealment cover during fawn‐rearing. We then used camera data to test the effects of time since fire on foraging behavior and found that with increased time since fire female white‐tailed deer are more likely to be feeding while foraging at concentrated resources of standardized quality and quantity. By combining these data, we revealed that the counterintuitive avoidance of high‐quality forage in recently burned areas can be explained by predation risk. We documented fire effects on proactive (i.e., avoidance of recent burns) and reactive (decreased vigilance with increasing time since fire) antipredator behaviors in white‐tailed deer during the fawning season. Our results suggest that fire can spatially and temporally alter a landscape causing dynamic predation risk to which prey must respond to maximize fitness.
Process Intensification of the Hydrogen Production Reaction Using a Carbon Membrane Reactor: Kinetics Analysis
Authors: Zhang Bing , Wang Dong , Zhou Jialing , Wu Yonghong , Zhao Dandan , Wang Tonghua , Qiu Jieshan 
Published: April 2017

AbstractPlate carbon membranes were fabricated and coupled into a membrane reactor to intensify the steam reforming of methanol (SRM). The homemade Cu‐based catalyst and carbon membranes were characterized by using thermogravimetric analysis, X‐ray diffraction, N2 adsorption, and gas permeation. The effects of the reaction temperature, reactor type, and carbon membranes on the methanol conversion and hydrogen yield were investigated. The results show that the coupling of carbon membranes in the reactor improves the methanol conversion significantly. In addition, both the methanol conversion and reaction rate increase, and the hydrogen yield first decreases then increases as the reaction temperature was elevated from 220 to 300 °C. This indicates that both thermodynamic and kinetic factors contribute to the intensification of SRM in the carbon membrane reactor.
Effect of glyphosate acid on biochemical markers of periphyton exposed in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei
Authors: Iummato María Mercedes , Pizarro Haydée , Cataldo Daniel , Di Fiori Eugenia , dos Santos Afonso María , del Carmen Ríos de Molina María , Juárez Ángela Beatriz 
Published: April 2017

Abstract

Glyphosate is currently the most widely used herbicide in agricultural production. It generally enters aquatic ecosystems through surface water runoff and aerial drift. We evaluated the effect of glyphosate acid on biochemical parameters of periphyton exposed to concentrations of 1, 3, and 6 mg/L in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei. Periphyton ash-free dry weight, chlorophyll a content, carotene/chlorophyll a ratio, lipid peroxidation levels, and superoxide dismutase and catalase activities were determined at days 0, 1, 7, 14, and 26 of the experimental period. Ash-free dry weight was similar between control and glyphosate-treated periphyton in the absence of L. fortunei. The latter had significantly lower carotene to chlorophyll a ratios and enzyme activities, and higher lipid peroxidation levels and chlorophyll a content than the former. These results show an adverse effect of glyphosate on the metabolism of periphyton community organisms, possibly inducing oxidative stress. On the contrary, no differences were observed in any of these variables between control and glyphosate-treated periphyton in the presence of L. fortunei. Mussels probably attenuated the herbicide effects by contributing to glyphosate dissipation. The results also demonstrate that biochemical markers provide useful information that may warn of herbicide impact on periphyton communities. Environ Toxicol Chem 2017;36:1775–1784. © 2016 SETAC
Effects of city living on the mesolimbic reward system—An fmri study
Authors: Krämer Bernd , Diekhof Esther K. , Gruber Oliver 
Published: April 2017

AbstractBased on higher prevalence rates of several mental disorders for city dwellers, psychosocial stress effects of urban living have been proposed as an environmental risk factor contributing to the development of mental disorders. Recently, it was shown that amygdala activation differs between city dwellers and rural residents in response to a cognitive‐social stressor. Besides its influence on the amygdala, chronic stress also affects mesocorticolimbic brain regions involved in reward processing, and stress‐related dysregulation of the mesocorticolimbic dopamine system is thought to contribute to onset and manifestation of psychiatric disorders. Here, we investigated differences in reward systems functioning in 147 healthy subjects living either in cities or in less urban areas by means of functional magnetic resonance imaging during performance of the desire‐reason‐dilemma paradigm, which permits a targeted investigation of bottom–up activation and top–down regulation of the reward circuit. Compared with subjects from less urban areas, city dwellers showed an altered activation and modulation capability of the midbrain (VTA) dopamine system. City dwellers also revealed increased responses in other brain regions involved in reward processing and in the regulation of stress and emotions, such as amygdala, orbitofrontal, and pregenual anterior cingulate cortex. These results provide further evidence for effects of an urban environment on the mesolimbic dopamine system and the limbic system which may increase the risk to develop mental disorders. Hum Brain Mapp 38:3444–3453, 2017. © 2017 Wiley Periodicals, Inc.