bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational Insights into the Gold‐Catalyzed Ring‐Opening of Methylenecyclopropanes and Vinylcyclopropanes with Sulfonamides
Authors: Liu Yuan , Feng Sidi , Bao Xiaoguang 
Published: March 2018

AbstractComputational studies were carried out to investigate the mechanisms of gold‐catalyzed ring‐opening of methylenecyclopropanes (MCPs) and vinylcyclopropanes (VCPs), respectively, with sulfonamides to afford homoallylic amine intermediates, which would subsequently produce pyrrolidine derivatives. The detailed activation modes of MCPs mediated by the AuI catalyst were comprehensively explored. Computational results suggested that the activation of MCP by the AuI catalyst was less feasible. Instead, the AuI catalyst mediated activation of sulfonamides could result in the increased acidity of the N−H bond, which is ready to undergo intermolecular proton transfer to the C=C moiety of MCP to form a cyclopropylcarbinyl cation intermediate. Subsequently, the nucleophilic attack of the formed amido group to the three‐membered ring moiety of the yielded cyclopropylcarbinyl cation intermediate in an SN2 manner could follow to afford the ring‐opening homoallylic sulfonamide. In addition, computational studies indicated that such mechanistic pathway could also apply to the VCPs involved hydroamination with sulfonamides. The mechanism of triflic acid catalyzed hydroamination of MCPs and VCPs with sulfonamides also proceeds via the cyclopropylcarbinyl cation intermediates formed by the protonation of the alkene moiety of MCPs and VCPs, respectively. The ineffectiveness of amines as aminating reagents in the AuI‐catalyzed hydroamination of MCPs and VCPs was discussed.
Silica Metal Oxide Vesicles Catalyze Comprehensive Prebiotic Chemistry
Authors: Mattia Bizzarri Bruno , Botta Lorenzo , Pérez‐Valverde Maritza Iveth , Saladino Raffaele , Di Mauro Ernesto , García‐Ruiz Juan Manuel 
Published: March 2018

AbstractIt has recently been demonstrated that mineral self‐assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth‐like planets. We have synthesized self‐assembled membranes by mixing microdrops of metal solutions with alkaline silicate solutions in the presence of formamide (NH2CHO), a single‐carbon molecule, at 80 °C. We found that these bilayer membranes, made of amorphous silica and metal oxide/hydroxide nanocrystals, catalyze the condensation of formamide, yielding the four nucleobases of RNA, three amino acids and, several carboxylic acids in a single‐pot experiment. Besides manganese, iron and magnesium, two abundant elements in the earliest Earth crust that are key in serpentinization reactions, are enough to produce all these biochemical compounds. These results suggest that the transition from inorganic geochemistry to prebiotic organic chemistry is common on a universal scale and, most probably, occurred earlier than ever thought for our planet.
New Approach for the Non‐redundant Modeling of Complex Chemical Reactions
Authors: Borovinskaya Ekaterina S. 
Published: March 2018

AbstractAn approach on how to formulate redundancy‐free models for mathematical descriptions of complex chemical reactions is introduced. This is based on an automatically created redundant (generalized) model, which is formulated according to the complete reaction network. These redundancy‐free models can be obtained as a result of either a step‐by‐step, or a one‐step elimination of model parameters, with the help of sensitivity and interval analysis. An example of this procedure is demonstrated using n‐decane isomerization. Starting with a 24‐parameter in the redundant model, the redundancy‐free model includes only 8 parameters.
The role of silver minerals on the cyanidation of gold particles embedded within multi‐sulphidic mineral matrices
Authors: Khalid Muhammad , Larachi Faïçal , Adnot Alain 
Published: March 2018

AbstractThe effect of silver minerals on the dissolution behaviour of gold particles embedded within multi‐sulphidic minerals was investigated. A multi‐layer packed‐bed reactor approach was used to study the leaching behaviour of free gold (within silica) and gold associated with a series of synthetic multi‐mineral systems consisting of pyrite, silica, and successively, X = chalcopyrite, sphalerite, and stibnite. The reactor was filled with sieved powders of sulphidic minerals (pyrite, X), gold and silica and arranged as electrically‐isolated three‐layer //Pyrite//X//Silica// and two‐layer //Pyrite + X//Silica// systems. Gold powder was introduced successively in each layer of the three‐ and two‐layer mineral systems and the gold leaching behaviour was studied. The highest gold recovery was achieved for the gold particles within the pyrite layer while the lowest was within the silica layer. In case of the //Pyrite//Stibnite//Silica// system, the surface passivation inhibited gold leaching strongly. Gold cyanidation experiments were also performed with the addition of silver minerals, with both Au and Ag minerals dispersed in a three‐layer //Pyrite//X//Silica// and two‐layer //Pyrite + X//Silica// systems. Silver minerals addition proved beneficial for the pyrite‐sphalerite‐silica system. Gold leaching was severely retarded for the pyrite‐chalcopyrite‐silica and pyrite‐stibnite‐silica systems. Passivating films were observed at the surface of gold particles in case of gold cyanidation with pyrite‐chalcopyrite‐silica and pyrite‐stibnite‐silica systems.
Bi‐, Y‐Codoped TiO2 for Carbon Dioxide Photocatalytic Reduction to Formic Acid under Visible Light Irradiation
Authors: Du Pengju , Su Tongming , Luo Xuan , Zhou Xiantai , Qin Zuzeng , Ji Hongbing , Chen Jianhua 
Published: March 2018

AbstractBi‐ and Y‐codoped TiO2 photocatalysts were synthesized through a sol‐gel method, and they were applied in the photocatalytic reduction of CO2 to formic acid under visible light irradiation. The results revealed that, after doping Bi and Y, the surface area of TiO2 was increased from 5.4 to 93.1 m2/g when the mole fractions of doping Bi and Y were 1.0% and 0.5%, respectively, and the lattice structures of the photocatalysts changed and the oxygen vacancies on the surface of the photocatalysts formed, which would act as the electron capture centers and slow down the recombination of photo‐induced electron and hole. The photocurrent spectra also proved that the photocatalysts had better electronic transmission capacities. The HCOOH yield in CO2 photocatalytic reduction was 747.82 μmol/gcat by using 1% Bi‐0.5% Y‐TiO2 as a photocatalyst. The HCOOH yield was 1.17 times higher than that by using 1% Bi‐TiO2, and 2.23 times higher than that by using pure TiO2. Furthermore, the 1% Bi‐0.5% Y‐TiO2 showed the highest apparent quantum efficiency (AQE) of 4.45%.
Achievement of multiple therapeutic targets for cardiovascular disease prevention: Retrospective analysis of real practice in Italy
Authors: Figliuzzi Ilaria , Presta Vivianne , Citoni Barbara , Miceli Francesca , Simonelli Francesca , Battistoni Allegra , Coluccia Roberta , Ferrucci Andrea , Volpe Massimo , Tocci Giuliano 
Published: March 2018

BackgroundPharmacological therapy in patients at high cardiovascular (CV) risk should be tailored to achieve recommended therapeutic targets.HypothesisTo evaluate individual global CV risk profile and to estimate the control rates of multiple therapeutic targets for in adult outpatients followed in real practice in Italy.MethodsData extracted from a cross‐sectional, national medical database of adult outpatients in real practice in Italy were analyzed for global CV risk assessment and rates of control of major CV risk factors, including hypertension, dyslipidemia, diabetes, and obesity. CV risk characterization was based on the European SCORE equation and the study population stratified into 3 groups: low risk (<2%), intermediate risk (≥2%–<5%), and high to very high risk (≥5%).ResultsWe analyzed data from 7158 adult outpatients (mean age, 57.7 ±5.3 years; BMI, 28.3 ±5.0 kg/m2, BP, 136.0 ±14.3/82.2 ±8.3 mm Hg; total cholesterol, 212.7 ±40.7 mg/dL), among whom 2029 (45.2%) had low, 1730 (24.2%) intermediate, and 731 (16.3%) high to very high risk. Increased SCORE risk was an independent predictor of poor achievement of diastolic BP <90 mm Hg (OR: 0.852, 95% CI: 0.822–0.882), LDL‐C < 130 mg/dL (OR: 0.892, 95% CI: 0.861–0.924), HDL‐C > 40 (males)/>50 (females) mg/dL (OR: 0.926, 95% CI: 0.895–0.958), triglycerides <160 mg/dL (OR: 0.925, 95% CI: 0.895–0.957), and BMI <25 kg/m2 (OR: 0.888, 95% CI: 0.851–0.926), even after correction for diabetes, renal function, pharmacological therapy, and referring physicians (P < 0.001).ConclusionsDespite low prevalence and optimal medical therapy, individuals with high to very high SCORE risk did not achieve recommended therapeutic targets in a real‐world practice.
Cardiac resynchronization therapy is associated with a reduction in ICD therapies as it improves ventricular function
Authors: Galve Enrique , Oristrell Gerard , Acosta Gabriel , Ribera‐Solé Aida , Moya‐Mitjans Àngel , Ferreira‐González Ignacio , Pérez‐Rodon Jordi , García‐Dorado David 
Published: March 2018

BackgroundRepeated implantable cardioverter‐defibrillator (ICD) therapies cause myocardial damage and, thus, an increased risk of arrhythmias and mortality.HypothesisCardiac resynchronization therapy–defibrillator (CRT‐D) reduces the number of appropriate therapies in patients with left ventricular dysfunction (left ventricular ejection fraction [LVEF] <50%).MethodsThe retrospective study involved 175 consecutive patients (mean age, 64.6 ±10.4 years; 86.9% males) with reduced LVEF of 27.9% ±7.6% treated with an ICD (56.6%) or CRT‐D (43.4%), according to standard indications, between January 2009 and July 2014. Devices were placed for either primary (54.3%) or secondary prevention (45.7%). Mean follow‐up was 2.5 ±1.5 years. Predictors of first appropriate therapy were assessed using Cox regression analysis.ResultsForty‐four (25.1%) patients received ≥1 appropriate therapy. Although patients treated with CRT‐D had lower LVEF and poorer New York Heart Association class, CRT‐D patients with LVEF improvement >35% at the end of follow‐up had a significantly lower risk of receiving a first appropriate therapy relative to those with an ICD (adjusted hazard ratio: 0.24, 95% confidence interval: 0.07–0.83, P = 0.025), independently of ischemic cardiomyopathy, baseline LVEF, and secondary prevention. There were no differences in mortality between the ICD and the CRT‐D groups.ConclusionsAlthough patients receiving CRT‐D had a worse clinical profile, they received fewer device therapies in comparison with those receiving an ICD. This reduction is associated with a significant improvement in LVEF.
Distribution of vesicular glutamate transporters in the brain of the turtle (Pseudemys scripta elegans)
Authors: Sarkar Sonjoy , Atoji Yasuro 
Published: March 2018

AbstractThe distribution of glutamatergic neurons has been extensively studied in mammalian and avian brains, but its distribution in a reptilian brain remains unknown. In the present study, the distribution of subpopulations of glutamatergic neurons in the turtle brain was examined by in situ hybridization using probes for vesicular glutamate transporter (VGLUT) 1–3. Strong VGLUT1 expression was observed in the telencephalic pallium; the mitral cells of the olfactory bulb, the medial, dorsomedial, dorsal, and lateral parts of the cerebral cortex, pallial thickening, and dorsal ventricular ridge; and also, in granule cells of the cerebellar cortex. Moderate to weak expression was found in the lateral and medial amygdaloid nuclei, the periventricular cellular layer of the optic tectum, and in some brainstem nuclei. VGLUT2 was weakly expressed in the telencephalon but was intensely expressed in the dorsal thalamic nuclei, magnocellular part of the isthmic nucleus, brainstem nuclei, and the rostral cervical segment of the spinal cord. The cerebellar cortex was devoid of VGLUT2 expression. The central amygdaloid nucleus did not express VGLUT1 or VGLUT2. VGLUT3 was localized in the parvocellular part of the isthmic nucleus, superior and inferior raphe nuclei, and cochlear nucleus. Our results indicate that the distribution of VGLUTs in the turtle brain is similar to that in the mammalian brain rather than that in the avian brain.
Experimental Observation and Mitigation of Dielectric Screening in Hexagonal Boron Nitride Based Resistive Switching Devices
Authors: Wang Bingru , Xiao Na , Pan Chengbin , Shi Yuanyuan , Hui Fei , Jing Xu , Zhu Kaichen , Guo Biyu , Villena Marco A. , Miranda Enrique , Lanza Mario 
Published: April 2018

AbstractMoisture and water penetration is one of the main phenomena altering the electrical characteristics and performance of resistive switching (RS) devices based on metal/insulator/metal nanojunctions. However, the effect of these phenomena in RS devices made of two dimensional (2D) materials has never been studied. In this paper it is shown that 2D materials based RS devices exposed to high relative humidity environments develop dielectric screening effects. The devices measured right after fabrication show a yield of 95% and bipolar RS characteristics, while after exposure to humid environments for two months the yield decreases to 65%. More than 30% of the devices show much lower currents than the fresh counterparts, and at high voltages they exhibit clear dielectric screening effects. This behavior is even more accentuated in RS devices that require the transfer of the 2D material, and we observe that a baking step at 120 °C for 5 min can mitigate this effect.
MARCKS phosphorylation by PKC strongly impairs cell polarity in the chick neural plate
Authors: Aparicio Gonzalo , Arruti Cristina , Zolessi Flavio R. 
Published: March 2018

SummaryNeurulation involves a complex coordination of cellular movements that are in great part based on the modulation of the actin cytoskeleton. MARCKS, an F‐actin‐binding protein and the major substrate for PKC, is necessary for gastrulation and neurulation morphogenetic movements in mice, frogs, and fish. We previously showed that this protein accumulates at the apical region of the closing neural plate in chick embryos, and here further explore its role in this process and how it is regulated by PKC phosphorylation. PKC activation by PMA caused extensive neural tube closure defects in cultured chick embryos, together with MARCKS phosphorylation and redistribution to the cytoplasm. This was concomitant with an evident disruption of neural plate cell polarity and extensive apical cell extrusion. This effect was not due to actomyosin hypercontractility, but it was reproduced upon MARCKS knockdown. Interestingly, the overexpression of a nonphosphorylatable form of MARCKS was able to revert the cellular defects observed in the neural plate after PKC activation. Altogether, these results suggest that MARCKS function during neurulation would be to maintain neuroepithelial polarity through the stabilization of subapical F‐actin, a function that appears to be counteracted by PKC activation.
Transition probabilities help identify putative drivers of community change in complex systems
Authors: Morello Scott L. , Etter Ron J. 
Published: March 2018

AbstractUnderstanding the role of larger‐scale processes in modulating the assembly, structure, and dynamics of communities is critical for forecasting the effects of climate‐change and managing ecosystems. Developing this comprehensive perspective is difficult though, because species interactions are complex, interdependent, and dynamic through space and time. Typically, experiments focus on tractable subsets of interactions that will be most critical to investigate and explain shifts in communities, but qualitatively base these choices on experience, natural history, and theory. One quantitative approach to identify the putative forces regulating communities, without reducing system complexity, is estimating transition probabilities among species occupying space (i.e., multispecies Markov chain models). Although not mechanistic, these models estimate the relative frequency and importance of ecological pathways in community assembly and dynamics, and can serve as a framework to identify how pathways change across large scales and which are most important to investigate further. Here, we demonstrate this method in the Gulf of Maine (GOM) intertidal zone, where research has largely focused on the local‐scale processes that influence communities, while the mechanisms responsible for more regional shifts in communities are less clear. Transition probabilities of faunal elements were quantified bimonthly for ~2.5 yr in local intertidal communities at three replicate sites in the southern, mid‐coast, and northern GOM. Transitions related to mortality, colonization, and replacement by mussels, barnacles, red algae, and encrusting corallines differed regionally, suggesting specific pathways related to consumer pressure and recruitment vary across the GOM with shifting intertidal community structure. Combined with species abundance data and insights from previous research, we develop and evaluate the pathways by which communities likely change in the GOM. Species interactions in local communities can be complex, and this complexity should be incorporated into hypothesis building, experiments, theory, interpretations, and forecasts in ecology. Such a comprehensive approach will be critical to understand how regional shifts in local interactions can drive large‐scale community change.
Imagined contact with famous gay men and lesbians reduces heterosexuals’ misidentification concerns and sexual prejudice
Authors: LaCosse Jennifer , Plant E. Ashby 
Published: March 2018

AbstractGay men and lesbians experience bigotry at alarmingly high rates. Traditionally, researchers have focused on reducing sexual prejudice; however, research indicates that heterosexuals’ concerns about being misidentified as gay/lesbian also contribute to the derogation of gay/lesbian individuals. Thus, reducing misidentification concerns is a critical part of decreasing negativity toward gay/lesbian individuals. In the current work, we explored a novel addition to the imagined contact paradigm—imagined contact with famous outgroup members—for reducing misidentification concerns. We found that imagined contact with famous gay men/lesbians reduced misidentification concerns within the imagined interaction and engendered an eagerness to befriend the famous gay/lesbian interaction partner. Moreover, we found that the reduction of these misidentification concerns led to fewer general contagion concerns, and increased eagerness to befriend led to decreased sexual prejudice. The current work develops a useful intervention for improving multiple responses toward gay men and lesbians.
Electrochemical Determination of Neurotransmitters at Crown Ether Modified Carbon Nanotube Composite: Application for Sub‐nano‐sensing of Serotonin in Human Serum
Authors: Atta Nada F. , Ahmed Yousef M. , Galal Ahmed 
Published: March 2018

AbstractWe propose an electrochemical sensor based on applying two successive thin layers from a mixture of multiwalled carbon nanotubes‐ionic liquid crystal and crown ether at glassy carbon electrode surface (GC/(CNTs‐ILC)/Crown). The sensor was used for sensitive determination of neurotransmitters based on effective synergism between its components. The compact conducting surface of (CNTs‐ILC) with large surface area allowed the assembling of stable host‐guest inclusion complexes between crown ethers and neurotransmitters. The GC/(CNTs‐ILC)/Crown exhibited excellent electro‐catalytic activity toward the determination of serotonin (ST) in a wide linear dynamic range: 0.005 μmol L−1 to 100 μmol L−1. In the concentration range 0.005 μmol L−1 to 1 μmol L−1, the detection limit is 2.03×10−10 mol L−1 and quantification limit is 6.78×10−10 mol L−1 with correlation coefficient 0.999. The sensor was successfully applied for ST detection in human serum samples with satisfied recovery results. The sensor showed excellent analytical performance for the determination of ST in terms of low detection limit, good sensitivity and reproducibility. Furthermore excellent anti‐interference ability and simultaneous determination of ST in presence of other compounds as ascorbic acid, dopamine and antidepressant drug were achieved.
Performance of Activated‐Carbon‐Supported Ni, Co, and Ni–Co Catalysts for Hydrogen Iodide Decomposition in a Thermochemical Water‐Splitting Sulfur–Iodine Cycle
Authors: Singhania Amit , Bhaskarwar Ashok N. 
Published: March 2018

AbstractBimetallic Ni–Co/activated carbon (Ni–Co/AC) and monometallic Ni/AC and Co/AC catalysts were prepared to investigate their catalytic activity for hydrogen‐iodide decomposition in the sulfur–iodine (SI) cycle. Transmission electron microscopy (TEM) revealed an average size of approximately 3 nm particles for Ni–Co/AC. Ni–Co/AC possesses a higher ID/IG intensity ratio in Raman spectroscopy than the monometallic catalysts and support, which is an indication of high degree of defects. Hydrogen‐iodide decomposition was performed on a fixed vertical bed quartz reactor at a weight hourly space velocity (WHSV) of 12.9 h−1 and different temperatures (400–550 °C). Bimetallic catalysts exhibited better activity and stability than the monometallic catalysts. The composition of Ni/Co in the bimetallic Ni–Co catalyst played the key role in dictating the activity of catalyst. It was observed that the loading ratio of 3:1 for Ni/Co achieved the maximal hydrogen‐iodide conversion value. Bimetallic Ni(3 %)–Co(1 %)/AC showed excellent time‐on‐stream stability of 70 h for the hydrogen‐iodide decomposition reaction. The post‐reaction characterization studies (X‐ray diffraction and Brunauer–Emmett–Teller surface area measurements) confirmed that the bimetallic Ni–Co/AC catalyst has a stable structure and shows high corrosion resistance against the corrosive hydrogen iodide environment. Also, it was observed that the apparent activation energy of the bimetallic Ni–Co/AC catalyst was smaller than the monometallic Ni and Co catalysts. The effect of iodine on hydrogen‐iodide conversion was also studied.
Catalytic Conversion of Carbohydrates into 5‐Ethoxymethylfurfural by a Magnetic Solid Acid Using γ‐Valerolactone as a Co‐Solvent
Authors: Bai Yuan‐Yuan , Su Shihao , Wang Shuizhong , Wang Bo , Sun Run‐Cang , Song Guoyong , Xiao Ling‐Ping 
Published: March 2018

AbstractSelective conversion of carbohydrates to fuels and fine chemicals is of great importance for biorefinery. However, development of efficient solid acidic catalysts which perform stably for this process is still challenging. Herein, we reported a novel carbon‐based solid acidic catalyst, prepared via hydrothermal carbonization of glucose followed by magnetization of Fe3O4 and sulfonation of H2SO4, which can serve as an efficient and recyclable catalyst in the catalytic dehydration of fructose to 5‐hydroxymethylfurfural (HMF) and subsequent etherification of 5‐ethoxymethylfurfural (EMF) with ethanol from various carbohydrates. The effects of reaction conditions (temperature, time, solvents, catalyst amount, and γ‐valerolactone (GVL) concentration) were optimized affording to a maximum EMF yield of 67.4 % at 120 °C, 55 wt % catalyst loading based on starting fructose and 60 vol.% of GVL in ethanol after 24 h of reaction. Noticeably, GVL promotes the formation of EMF and HMF reducing the extent of side reactions. Recycling experiments showed that the catalyst could be easily separated with a magnet and reused up to 4 consecutive times without significant loss of activity. The present work opens a way to synthesize reusable and cost‐effective solid acidic catalysts from biomass wastes and may contribute to a holistic approach for biomass valorization.