bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of the tropical West Pacific in the extreme Northern Hemisphere winter of 2013/2014
Authors: Watson Peter A. G. , Weisheimer Antje , Knight Jeff R. , Palmer T. N. 
Published: February 2016

AbstractIn the 2013/2014 winter, the eastern U.S. was exceptionally cold, the Bering Strait region was exceptionally warm, California was in the midst of drought, and the UK suffered severe flooding. It has been suggested that elevated sea surface temperatures (SSTs) in the tropical West Pacific (TWPAC) were partly to blame due to them producing a Rossby wave train that propagated into the extratropics. We find that seasonal forecasts with the tropical atmosphere relaxed toward a reanalysis give 2013/2014 winter mean anomalies with strong similarities to those observed in the Northern Hemisphere, indicating that low‐latitude anomalies had a role in the development of the extremes. Relaxing just the TWPAC produces a strong wave train over the North Pacific and North America in January, but not in the winter mean. This suggests that anomalies in this region alone had a large influence but cannot explain the extremes through the whole winter. We also examine the response to applying the observed TWPAC SST anomalies in two atmospheric general circulation models. We find that this does produce winter mean anomalies in the North Pacific and North America resembling those observed and that the tropical forcing of Rossby waves due to the applied SST anomalies appears stronger than that in reanalysis, except in January. Therefore, both experiments indicate that the TWPAC influence was important, but the true strength of the TWPAC influence is uncertain. None of the experiments indicate a strong systematic impact of the TWPAC anomalies on Europe.
Simulating California reservoir operation using the classification and regression‐tree algorithm combined with a shuffled cross‐validation scheme
Authors: Yang Tiantian , Gao Xiaogang , Sorooshian Soroosh , Li Xin 
Published: February 2016

AbstractThe controlled outflows from a reservoir or dam are highly dependent on the decisions made by the reservoir operators, instead of a natural hydrological process. Difference exists between the natural upstream inflows to reservoirs and the controlled outflows from reservoirs that supply the downstream users. With the decision maker's awareness of changing climate, reservoir management requires adaptable means to incorporate more information into decision making, such as water delivery requirement, environmental constraints, dry/wet conditions, etc. In this paper, a robust reservoir outflow simulation model is presented, which incorporates one of the well‐developed data‐mining models (Classification and Regression Tree) to predict the complicated human‐controlled reservoir outflows and extract the reservoir operation patterns. A shuffled cross‐validation approach is further implemented to improve CART's predictive performance. An application study of nine major reservoirs in California is carried out. Results produced by the enhanced CART, original CART, and random forest are compared with observation. The statistical measurements show that the enhanced CART and random forest overperform the CART control run in general, and the enhanced CART algorithm gives a better predictive performance over random forest in simulating the peak flows. The results also show that the proposed model is able to consistently and reasonably predict the expert release decisions. Experiments indicate that the release operation in the Oroville Lake is significantly dominated by SWP allocation amount and reservoirs with low elevation are more sensitive to inflow amount than others.
Preparation and Evaluation of Novel pH‐Sensitive Poly(butyl acrylate‐co‐itaconic acid) Hydrogel Microspheres for Controlled Drug Delivery
Authors: Razzaq Rabia , Ranjha Nazar Mohammad , Rashid Zermina , Nasir Bushra 
Published: February 2016

ABSTRACTIn this study, a series of novel pH‐sensitive copolymeric butyl acrylate‐co‐itaconic acid (p(BA‐co‐IA)) hydrogel microspheres were prepared by modified suspension polymerization of butyl acrylate and itaconic acid with the addition of 5% ethylene glycol dimethacrylate as a cross‐linker and 1% benzoyl peroxide as an initiator. Nifedipine, an antihypertensive drug, was successfully encapsulated into these hydrogel microspheres by the equilibrium swelling method. Prepared hydrogel micropsheres were evaluated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X‐ray diffractometry (XRD), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The chemical stability of the nifedipine after being encapsulated into prepared hydrogel microspheres was confirmed by FTIR, DSC, and XRD analysis. TGA indicates that prepared samples showed much better thermal stability than pure drug nifedipine. SEM images showed that prepared p(BA‐co‐IA) hydrogel microspheres are spherical in shape. The size distribution of prepared samples was found between 4.145 to 10 μm using a Malvern nanosize ZS instrument. The maximum percentage entrapment efficiency of nifedipine was found 67%, and % yield was about 72%. The maximum in vitro release studies of drug‐loaded microspheres, which is 94.4% for the pH 7.4 buffer solution, demonstrated the pH sensitivity of prepared hydrogel microspheres. The cumulative drug release data were analyzed by using the Korsmeyer–Peppas equation to calculate a value of diffusion exponent (n), which follows non‐Fickian diffusion.
Extended Motor Evoked Potentials Monitoring Helps Prevent Delayed Paraplegia After Aortic Surgery
Authors: See Reiner B. , Awosika Oluwole O. , Cambria Richard P. , Conrad Mark F. , Lancaster Robert T. , Patel Virendra I. , Chitilian Hovig V. , Kumar Sandeep , Simon Mirela V. 
Published: February 2016

ObjectiveMotor evoked potentials (MEPs) monitoring can promptly detect spinal cord ischemia (SCI) from aortic clamping during open thoracoabdominal aneurysm repair (OTAAR) with distal aortic perfusion (DAP) and thus help decrease the risk of immediate postoperative SCI (IP‐SCI). However, neither stable MEPs during aortic clamp interval (ACI) nor absence of IP‐SCI eliminate the possibility of delayed postoperative SCI (DP‐SCI). We hypothesized that extension of MEPs monitoring beyond ACI can also help decrease the risk of DP‐SCI.MethodsWe identified 150 consecutive patients at our institution between April 2005 and October 2014 who underwent OTAAR with DAP and MEPs monitoring and had no IP‐SCI. Using logistic regression analysis, we studied the independent effect of extended MEPs monitoring on the risk of developing DP‐SCI. We used a propensity score analysis to adjust for potential confounders, such as poorly controlled hypertension, previous aneurysm surgery, splenectomy, acute aortic dissection, aneurysm type, older age, and history of diabetes and smoking.ResultsFrom the 150 patients, 129 (86%) remained neurologically intact whereas 21 (14%) developed DP‐SCI. Nineteen of these twenty‐one patients (90%) had no extended monitoring. Fifty‐seven of fifty‐nine (97%) patients who benefited from extended monitoring had no DP‐SCI (p = 0.003). Extended MEPs monitoring was independently associated with decreased risk of DP‐SCI (odds ratio = 0.14; 95% confidence interval: 0.03, 0.65; p = 0.01).InterpretationMEPs detect the lowest systemic blood pressure that ensures appropriate spinal cord perfusion in the postoperative period. Thus, they inform the hemodynamic management of patients post‐OTAAR, particularly in the absence of a reliable neurological exam. Ann Neurol 2016;79:636–645
Effect of a polymer on chromium(III) diffusion during gelant injection in fractured media
Authors: Bai Yingrui , Li Junjian , Xiong Chunming , Shang Xiaosen , Wei Falin , Zhang Miao 
Published: February 2016

ABSTRACTThe effect of a polymer on chromium diffusion during gelant injection into fractured media was explored with a polymer/chromium(III) (Cr3+) gelant. The capture and barrier effects are two main affecting mechanisms of polymer molecules on the diffusion of Cr3+, and the formation of the polymer leak‐off layer is a key influencing factor. The experimental results show that when the polymer molecular weight (MW) or concentration increased, both the diffusion rate of Cr3+ and the leak‐off degree of the gelant decreased sharply. This resulted in the delayed initial production and advanced final production of Cr3+. Because of the changing diffusion rate of Cr3+ and the dilution effect of brine during gelant injection, the change trends of the Cr3+ production from the fracture outlet and matrix ports reversed after the injection volume exceeded a value; this value was named the critical injected volume. During gelant injection into the fractures, under the effects of gravity action and the disproportionate diffusion of Cr3+, the chromium diffusion profiles measured at the fracture top and bottom were different. The chromium diffusion profile along the matrix varied with increasing gelant injected volume, but it finally reached the diffusion equilibrium state in the matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43447.
Enantiomeric resolution of multiple chiral centres racemates by capillary electrophoresis
Authors: Ali Imran , Suhail Mohd. , AL‐Othman Zeid A. , Alwarthan Abdulrahman , Aboul‐Enein Hassan Y. 
Published: February 2016

AbstractEnantiomeric resolution of multichiral centre racemates is an important area as some multichiral centre racemates are of great medicinal importance. However, enantioseparation of such types of racemates is a challenging task. Amongst many analytical techniques, capillary electrophoresis is a powerful technique and may be used to resolve such racemates. Only few papers are available describing enantiomeric resolution of such racemates. Therefore, efforts have been made to describe the enantiomeric resolution of multichiral centre racemates by capillary electrophoresis. This article discusses the importance of multichiral racemates, the need for capillary electrophoresis in enantiomeric resolution and chiral resolution of multichiral centre racemates using various chiral selectors. Further, attempts have been made to discuss the future challenges and prospects of enantiomeric resolution of multichiral racemates. The various chiral selectors used for the purpose are chiral crown ether, cyclodextrins, polysaccharides, macrocyclic glycopeptide antibiotics and ligand exchange. Copyright © 2016 John Wiley & Sons, Ltd.
The Role of a Nonribosomal Peptide Synthetase in l‐Lysine Lactamization During Capuramycin Biosynthesis
Authors: Liu Xiaodong , Jin Yuanyuan , Cui Zheng , Nonaka Koichi , Baba Satoshi , Funabashi Masanori , Yang Zhaoyong , Van Lanen Steven G. 
Published: February 2016

AbstractCapuramycins are one of several known classes of natural products that contain an l‐Lys‐derived l‐α‐amino‐ɛ‐caprolactam (l‐ACL) unit. The α‐amino group of l‐ACL in a capuramycin is linked to an unsaturated hexuronic acid component through an amide bond that was previously shown to originate by an ATP‐independent enzymatic route. With the aid of a combined in vivo and in vitro approach, a predicted tridomain nonribosomal peptide synthetase CapU is functionally characterized here as the ATP‐dependent amide‐bond‐forming catalyst responsible for the biosynthesis of the remaining amide bond present in l‐ACL. The results are consistent with the adenylation domain of CapU as the essential catalytic component for l‐Lys activation and thioesterification of the adjacent thiolation domain. However, in contrast to expectations, lactamization does not require any additional domains or proteins and is likely a nonenzymatic event. The results set the stage for examining whether a similar NRPS‐mediated mechanism is employed in the biosynthesis of other l‐ACL‐containing natural products and, just as intriguingly, how spontaneous lactamization is avoided in the numerous NRPS‐derived peptides that contain an unmodified l‐Lys residue.
Dual‐Layer Hollow Fibers for Sulfur Removal from Fuels
Authors: Amaral Rafael A. , Borges Cristiano P. , Habert Alberto C. , Mermier Nicolas R. J.‐D. 
Published: February 2016

AbstractEmission of sulfur compounds to the atmosphere is universally recognized as one key target to be reduced. For membrane pervaporation which is considered as a potential purification process of fuels, dual‐layer polyurethane (PU)/polyethersulfone hollow‐fiber membranes were prepared. A novel fabrication technique is proposed using a quadruple spinneret to produce the fiber with such morphology by simultaneous spinning of two polymer solutions in the presence of two corresponding precipitation media. Activated carbon was added into the PU solution to improve the transport properties of the selective layer. Resulting hollow‐fiber membranes showed very good adhesion between the selective layer and its support, in addition to an effective removal of a sulfur compound such as 2‐methyl thiophene from a typical model fuel, an indication of good prospects for both the fabrication technique and for sulfur removal by pervaporation of fuels.
Rheology‐Based Computational Fluid Dynamics Modeling for De‐oiling Hydrocyclone Efficiency
Authors: Li Changjun , Huang Qian 
Published: February 2016

AbstractThe de‐oiling hydrocyclone belongs to the most effective devices to recover oil from oily wastewater. An improved multiphase computational fluid dynamics (CFD) model is developed for simulating oil‐water separation in a de‐oiling hydrocyclone. This model approach uses the Reynolds stress model to resolve the turbulent and the modified mixture model with a new viscosity correlation of oil‐in‐water (O/W) emulsions. This modified model of emulsion viscosity based on the power law equation and experimental data of three types of crude oil is introduced to predict the viscosity of O/W emulsions. A comparison between experimental and predicted values of separation efficiency demonstrates that multiphase simulations with the modified model of viscosity provide a better accuracy than CFD models associated with original rheological models. This improved CFD model can be further applied in developing new designs in the future.
Homogeneous Catalytic Kinetics of Methyl Glycolate Hydrolysis
Authors: Xu Yan , Meh Ablikim , Yang Guangcun , Zhao Yujun , Chen Qu , Li Zhenhua , Ma Xinbin 
Published: February 2016

AbstractCatalytic hydrolysis of methyl glycolate is a promising way to produce glycolic acid with high purity. The hydrolysis of methyl glycolate was investigated both in a stirred‐batch reactor and in a reactive distillation column. Batch hydrolysis distillation was found to be rather effective in improving the conversion of methyl glycolate. A mechanism model including the cooperative catalysis of sulfuric acid and the generated glycolic acid was developed based on the acid‐catalyzed hydrolysis mechanism and the protolysis equilibrium; then, the model was further simplified according to the relationship between the concentrations of hydroxonium ions and their providers. This simplified model could be easily introduced to Aspen Plus and applied to simulating the homogeneous hydrolysis process of methyl glycolate with or without sulfuric acid as catalyst via the reactive distillation technique.
Synthesis of MnOx Water Oxidation Catalyst on Fluorine‐Doped Tin Oxide with a Dual‐Series Cyclic Voltammetry Method
Authors: Yuan Hao , Lunt Richard R. , Blanchard Gary J. , Ofoli Robert Y. 
Published: February 2016

AbstractThis Communication reports a new method for synthesizing manganese‐based water oxidation catalysts in situ in aqueous media. The method provides powerful tunability of the electrodeposition process to enable independent control over the morphology of the catalytic film and the oxidation state of the catalyst. Our results show that the first cyclic voltammetry (CV) series produces a film with a nanoscale fibrous structure, whereas the second CV series improves its catalytic performance by enhancing the oxidation state of the film without damaging the existing surface morphology. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology of the MnOx film, CV was used to assess the catalyst functionality, and long‐term amperometry was used to assess the stability.
Vertically Aligned Titanium Nitride Nanorod Arrays as Supports of Platinum–Palladium–Cobalt Catalysts for Thin‐Film Proton Exchange Membrane Fuel Cell Electrodes
Authors: Jiang Shangfeng , Yi Baolian , Zhang Hongjie , Song Wei , Bai Yangzhi , Yu Hongmei , Shao Zhigang 
Published: February 2016

AbstractThe degradation of the carbon supports and high platinum (Pt) loading significantly hinder the wide adoption of proton exchange membrane fuel cells. In conventional electrodes, the ionomer binders introduce an undesirable, high oxygen‐transport resistance and cover the catalysts active sites. Herein, an advanced catalytic layer based on vertically aligned titanium nitride nanorod arrays (TiN NRs) is prepared, without additional ionomer or binders in the cathode. After supporting the thin‐film platinum–palladium–cobalt (PtPdCo) catalyst (Pt loading: 66.9 μm cm−2) onto TiN NRs, the ordered electrodes were investigated as the cathode of a single cell without additional ionomer in the catalytic layer. With this electrode architecture, the as‐synthesized electrode performs with a maximum power density of 390.5 mW cm−2 and cathode mass‐specific power density of 5.84 W mgPt−1. The 2000 potential cycles accelerated degradation test shows that the PtPdCo–TiN electrode is more stable than the commercial gas diffusion electrode.
Metal–Organic Framework‐Templated Porous Carbon for Highly Efficient Catalysis: The Critical Role of Pyrrolic Nitrogen Species
Authors: Huang Gang , Yang Li , Ma Xiao , Jiang Jun , Yu Shu‐Hong , Jiang Hai‐Long 
Published: February 2016

AbstractMetal‐free catalysts are of great importance and alternative candidates to conventional metal‐based catalysts for many reactions. Herein, several types of metal–organic frameworks have been exploited as templates/precursors to afford porous carbon materials with various nitrogen dopant forms and contents, degrees of graphitization, porosities, and surface areas. Amongst these materials, the PCN‐224‐templated porous carbon material optimized by pyrolysis at 700 °C (denoted as PCN‐224‐700) is composed of amorphous carbon coated with well‐defined graphene layers, offering a high surface area, hierarchical pores, and high nitrogen content (mainly, pyrrolic nitrogen species). Remarkably, as a metal‐free catalyst, PCN‐224‐700 exhibits a low activation energy and superior activity to most metallic catalysts in the catalytic reduction of 4‐nitrophenol to 4‐aminophenol. Theoretical investigations suggest that the content and type of the nitrogen dopant play crucial roles in determining the catalytic performance and that the pyrrolic nitrogen species makes the dominant contribution to this activity, which explains the excellent efficiency of the PCN‐224‐700 catalyst well.
Spectral Signatures of Ultrafast Spin Crossover in Single Crystal [FeII(bpy)3](PF6)2
Authors: Field Ryan , Liu Lai Chung , Gawelda Wojciech , Lu Cheng , Miller R. J. Dwayne 
Published: February 2016

AbstractSolvated iron(II)‐tris(bipyridine) ([FeII(bpy)3]2+) has been extensively studied with regard to the spin crossover (SCO) phenomenon. Herein, the ultrafast spin transition dynamics of single crystal [FeII(bpy)3](PF6)2 was characterized for the first time using femtosecond transient absorption (TA) spectroscopy. The single crystal environment is of interest for experiments that probe the nuclear motions involved in the SCO transition, such as femtosecond X‐ray and electron diffraction. We found that the TA at early times is very similar to what has been reported in solvated [FeII(bpy)3]2+, whereas the later dynamics are perturbed in the crystal environment. The lifetime of the high‐spin state is found to be much shorter (100 ps) than in solution due to chemical pressure exerted by the lattice. Oscillatory behavior was observed on both time scales. Our results show that single crystal [FeII(bpy)3](PF6)2 serves as an excellent model system for localized molecular spin transitions.
Undeniable Confirmation of the syn‐Addition Mechanism for Metal‐Free Diboration by Using the Crystalline Sponge Method
Authors: Cuenca Ana B. , Zigon Nicolas , Duplan Vincent , Hoshino Manabu , Fujita Makoto , Fernández Elena 
Published: February 2016

AbstractThe stereochemical outcome of the recently developed metal‐free 1,2‐diboration of aliphatic alkenes has, until now, only been elucidated by indirect means (e.g. derivatization). This is because classical conformational analysis of the resulting 1,2‐diboranes is not viable; in the 1H NMR spectrum the relevant 1H resonances are broadened by 11B, and the occurrence of the products as oily compounds precludes X‐ray crystallographic analysis. Herein, the crystalline sponge method is used to display the crystal structures of the diboronic esters formed from internal E and Z olefins, evidencing the stereospecific syn addition mechanism of the reaction, which is fully consistent with the prediction from DFT calculations.
Visible Light‐Promoted Decarboxylative Di‐ and Trifluoromethylthiolation of Alkyl Carboxylic Acids
Authors: Candish Lisa , Pitzer Lena , Gómez‐Suárez Adrián , Glorius Frank 
Published: February 2016

AbstractDescribed herein is a new and straightforward decarboxylative di‐ and trifluoromethylthiolation of alkyl carboxylic acids promoted by visible light. This approach enables the synthesis of biologically relevant alkyl SCF2H and SCF3 compounds from cheap and abundant carboxylic acids. The method is operationally simple, using irradiation from household light sources, and its mild reaction conditions make it tolerant of a range of functional groups. The strategy employs electrophilic phthalimide‐derived di‐ and trifluoromethylthiolation reagents and exploits the ability of the imidyl radical to carry a radical chain.
Water Purification: Adsorption over Metal‐Organic Frameworks
Authors: Li Siqing , Chen Yifa , Pei Xiaokun , Zhang Shenghan , Feng Xiao , Zhou Junwen , Wang Bo 
Published: February 2016

AbstractWater pollution relating to human beings' health is a universal problem across community society. Highly efficient, economically feasible and easily achievable approaches are long‐sought‐after for water purification. Adsorption processes with porous materials (e.g. zeolites, activated carbon, silica gel, metal‐organic frameworks (MOFs)) have drawn much attention in this field during past decades. In it, MOFs with numerous active sites, uniform porosity and tailorable structure diversity are arising to be one of the most promising adsorbents for water purification. During the adsorption processes, influence factors that determine or affect the usability and performances of MOFs are mainly focused on the stability of MOFs, their affinity for contaminants and the conducting conditions (pH, initial concentration of the contaminants). In this review, we will systematically present the performances of MOFs (mainly focused on MOF crystals, MOF nanomaterial or MOF composites will be beyond the scope of this review) for contaminants purification (inorganic and organic contaminants) in water and give a detailed discussion about the connection among their performances, conducting condition factors and potential interaction mechanisms (e.g. electrostatic interactions, coordination or p‐p interaction). We hope this review will be beneficial to the design, regeneration and reuse of MOF adsorbents and promote the development of MOFs for water purification.