bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogen and oxygen isotopic compositions of water vapor over the Bay of Bengal during monsoon
Authors: Midhun M. , Lekshmy P. R. , Ramesh R. 
Published: November 2013

AbstractδDv and δ18Ov of ~70 water vapor samples collected at 6 and 25 m above sea level over the Bay of Bengal (BoB) during July–August 2012 are reported. This helps characterize the isotopic signature of monsoon vapor. No significant vertical variation is observed in δDv, δ18Ov, or deuterium excess (defined as δD–8δ18O); δDv and δ18Ov are significantly correlated (r = 0.92) at each height; the deuterium excess values do not, because the variation of δDv and δ18Ov relative to their uncertainties is much larger than that of the latter. The temporal variations of δDv and δ18Ov correlate well with air temperature rather than sea surface temperature. The control of normalized humidity on deuterium excess is less prominent. While the distribution of water vapor isotopologues over the BoB is primarily determined by the ocean surface conditions, they are significantly altered by laterally advected vapor from rain en route during the monsoon.
Convective amplification of electromagnetic ion cyclotron waves from ring‐distribution protons in the inner magnetosphere
Authors: Mithaiwala Manish , Crabtree Chris , Ganguli Gurudas , Rudakov Leonid , Keika Kunihiro 
Published: November 2013

AbstractThe growth of electromagnetic ion cyclotron (EMIC) waves due to a ring distribution of hydrogen ions is examined. Though these distributions are more commonly implicated in the generation of equatorial noise, their potential for exciting EMIC waves is considered here. It is shown that since the ring distribution is nonmonotonic in perpendicular velocity, the amplification achieved by this instability is greater than bi‐Maxwellian distributions for typical observed anisotropies, because the waves can maintain resonance over a much longer part of its trajectory. For ring speeds (Vr) close to the Alfvén speed (VA), the growth rate is largest at parallel propagation but decreases less rapidly toward oblique angles compared with a bi‐Maxwellian and can have a second peak for shorter wavelengths. The ring distribution parallel thermal speed is deduced from the observation of equatorial noise because a statistical survey of this parameter is not available. A ring density to background plasma density of a few percent is sufficient to achieve moderate gain. The gain is also shown to increase with L shell since the perpendicular wave number does not rise as rapidly along the raypath as compared with smaller L. The analysis suggests that EMIC wave activity should be closely associated with equatorial noise.
Palladium‐Catalyzed Reduction of Carboxylic Acids to Aldehydes with Hydrosilanes in the Presence of Pivalic Anhydride
Authors: Fujihara Tetsuaki , Cong Cong , Terao Jun , Tsuji Yasushi 
Published: November 2013

AbstractA palladium catalyst system that allows the reduction of carboxylic acids to the corresponding aldehydes with hydrosilanes as reducing agent and pivalic anhydride as an indispensable reagent has been developed. A simple mixture of commercially available bis(dibenzylideneacetone)palladium(0) [Pd(dba)2], tri(para‐tolyl)phosphane and methylphenylsilane realized the reduction of various aliphatic carboxylic acids as well as benzoic acids to aldehydes in good to high yields.magnified image
Chiral Phosphoric Acid‐Catalyzed Asymmetric Aza‐Friedel–Crafts Reaction of Indoles with Cyclic N‐Acylketimines: Enantioselective Synthesis of Trifluoromethyldihydroquinazolines
Authors: Zhang Ke‐Feng , Nie Jing , Guo Ran , Zheng Yan , Ma Jun‐An 
Published: November 2013

AbstractAn enantioselective aza‐Friedel–Crafts (F‐C) reaction of indoles with cyclic N‐acylketimines has been developed. By using chiral phosphoric acid catalysts, a wide range of enantioenriched trifluoromethyldihydroquinazolines was obtained in excellent yields (up to 98%) with good to high enantioselectivities (up to 99% ee).magnified image
Deoxycholic Acid‐Derived Biaryl Phosphites as Versatile and Enantioselective Ligands in the Rhodium‐Catalyzed Conjugate Addition of Arylboronic Acids to Nitroalkenes
Authors: Jumde Varsha R. , Iuliano Anna 
Published: November 2013

AbstractA highly enantioselective conjugate addition of arylboronic acids to cyclic as well as acyclic aromatic and aliphatic nitroalkenes is presented. The rhodium complexes obtained from deoxycholic acid‐derived binaphthyl and flexible biphenyl phosphites showed good activity as well as very high enantioselectivity (ee up to 99%) in the conjugated addition even in the presence of challenging substrates such as 1‐nitrocyclohexene or aliphatic acyclic nitroalkenes.magnified image
Phosphine‐Catalyzed Asymmetric [4+2] Annulation of Vinyl Ketones with Oxindole‐Derived α,β‐Unsaturated Imines: Enantioselective Syntheses of 2′,3′‐Dihydro‐1′H‐spiro[indoline‐3,4′‐pyridin]‐2‐ones
Authors: Zhang Xiao‐Nan , Chen Gen‐Qiang , Dong Xiang , Wei Yin , Shi Min 
Published: November 2013

AbstractA novel asymmetric [4+2] annulation of vinyl ketones with oxindole‐derived α,β‐unsaturated imines has been developed in the presence of a multifunctional thiourea‐phosphine catalyst derived from a natural amino acid, providing the first phosphine‐catalyzed enantioselective synthesis of 2′,3′‐dihydro‐1′H‐spiro[indoline‐3,4′‐pyridin]‐2‐ones in good yields with excellent stereoselectivities under mild conditions.magnified image
An Approach to Mixed PnAsm Ligand Complexes
Authors: Schwarzmaier Christoph , Bodensteiner Michael , Timoshkin Alexey Y. , Scheer Manfred 
Published: November 2013

AbstractThe reaction of a P4 butterfly complex with yellow arsenic yields the largest mixed PnAsm ligand complexes synthesized to date. [{Cp′′′Fe(CO)2}2(μ,η1:1‐P4)] reacts with As4 to yield [{Cp′′′Fe}2(μ,η4:4‐PnAs4‐n)] and [Cp′′′Fe(η5‐PnAs5‐n)]. Mass spectrometry together with NMR spectroscopy and X‐ray crystallography give clear evidence about the arrangement of the E positions within the cyclo‐E5 and E4 moieties of the products. Moreover, the results of DFT calculations agree well with the experimental determined outcomes. By coordinating the E4 complex [{Cp′′′Fe}2(μ,η4:4‐PnAs4‐n)] with CuCl, a rearrangement of the E positions occurs in favor with a preferred phosphorus coordination towards copper atoms in the resulting 1D polymeric chain.
PPh3‐Catalyzed Ring‐Expansion Reactions of Sulfamate‐Derived Cyclic Imines with Acetylenedicarboxylates
Authors: Yang Zhilin , Yu Hao , Zhang Lei , Wei Hang , Xiao Yumei , Chen Lanzhen , Guo Hongchao 
Published: November 2013

AbstractThe PPh3‐catalyzed ring‐expansion reaction of sulfamate‐derived cyclic imines with acetylenedicarboxylates has been developed. The reaction works quite efficiently under very mild conditions to afford benzo[g][1,2,3]oxathiazocine‐4,5‐dicarboxylate 2,2‐dioxide derivatives in high yields.
Superoxide Dismutase Activity of the Naturally Occurring Human Serum Albumin–Copper Complex without Hydroxyl Radical Formation
Authors: Kato Ryunosuke , Akiyama Matofusa , Kawakami Hiroyoshi , Komatsu Teruyuki 
Published: November 2013

AbstractThe superoxide radical anion (O2.−) is biologically toxic and contributes to the pathogenesis of various diseases. Here we describe the superoxide dismutase (SOD) activity of human serum albumin (HSA) complexed with a single CuII ion at the N‐terminal end (HSA–Cu complex). The structure of this naturally occurring copper‐coordinated blood serum protein has been characterized by several physicochemical measurements. The O2.− dismutation ability of the HSA–Cu (1:1) complex is almost the same as that of the well‐known SOD mimics, such as MnIII‐tetrakis(N‐methylpyridinium)porphyrin. Interestingly, the HSA–Cu complex does not induce a subsequent Fenton reaction to produce the hydroxyl radical (OH.), which is one of the most harmful reactive oxygen species.
A distance‐ and orientation‐dependent energy function of amino acid key blocks
Authors: Chen Lin , He Jing 
Published: November 2013

ABSTRACTBlocks are the selected portions of amino acids. They have been used effectively to represent amino acids in distinguishing the native conformation from the decoys. Although many statistical energy functions exist, most of them rely on the distances between two or more amino acids. In this study, the authors have developed a pairwise energy function “DOKB” that is both distance and orientation dependent, and it is based on the key blocks that bias the distal ends of side chains. The results suggest that both the distance and the orientation are needed to distinguish the fine details of the packing geometry. DOKB appears to perform well in recognizing native conformations when compared with six other energy functions. Highly packed clusters play important roles in stabilizing the structure. The investigation about the highly packed clusters at the residue level suggests that certain residue pairs in a low‐energy region have lower probability to appear in the highly packed clusters than in the entire protein. The cluster energy term appears to significantly improve the recognition of the native conformations in ig_structal decoy set, in which more highly packed clusters are contained than in other decoy sets. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 681–692, 2014.
Rate‐limiting step analysis of the microbial desulfurization of dibenzothiophene in a model oil system
Authors: Abin‐Fuentes Andres , Leung James C. , Mohamed Magdy El‐Said , Wang Daniel I.C. , Prather Kristala L.J. 
Published: November 2013

ABSTRACTA mechanistic analysis of the various mass transport and kinetic steps in the microbial desulfurization of dibenzothiophene (DBT) by Rhodococcus erythropolis IGTS8 in a model biphasic (oil–water), small‐scale system was performed. The biocatalyst was distributed into three populations, free cells in the aqueous phase, cell aggregates and oil–adhered cells, and the fraction of cells in each population was measured. The power input per volume (P/V) and the impeller tip speed (vtip) were identified as key operating parameters in determining whether the system is mass transport controlled or kinetically controlled. Oil–water DBT mass transport was found to not be limiting under the conditions tested. Experimental results at both the 100 mL and 4 L (bioreactor) scales suggest that agitation leading to P/V greater than 10,000 W/ m3 and/or vtip greater than 0.67 m/s is sufficient to overcome the major mass transport limitation in the system, which was the diffusion of DBT within the biocatalyst aggregates. Biotechnol. Biotechnol. Bioeng. 2014;111: 876–884. © 2013 Wiley Periodicals, Inc.
Primary hepatocellular carcinoma (“hepatoid” carcinoma) of the pancreas: a case report and review of the literature
Authors: Steen Shawn , Wolin Edward , Geller Stephen A. , Colquhoun Steven 
Published: November 2013

Key Clinical MessageWe present a case of hepatocellular carcinoma located within the pancreas. These tumors occur in the body and tail of the pancreas, with a male predominance, and at a younger age. Tumors with pure hepatocellular histopathology have better survival and recurrence rates and should be offered surgical therapy if possible.
Enhancement of Promiscuous Amidase Activity of a Bacillus subtilis Esterase by Formation of a π–π Network
Authors: Hackenschmidt Silke , Moldenhauer Eva J. , Behrens Geoffrey A. , Gand Martin , Pavlidis Ioannis V. , Bornscheuer Uwe T. 
Published: November 2013

AbstractOver the past decade, researchers have tried to decipher the borderline between serine proteases and carboxylic ester hydrolases; although they share the same catalytic triad, the factor that distinguishes their substrate preference still remains unknown. So far, the total inversion of the catalytic character has not yet been fulfilled; only minor improvements of the promiscuous amidase activity have been achieved for the carboxylic ester hydrolases compared to their natural activities, even though different sophisticated approaches of rational design have been applied. In the present study we used a combination of directed evolution and rational design to improve the promiscuous amidase activity of a Bacillus subtilis esterase. A double mutant was identified with 7.5 fold higher relative reaction specificity for the promiscuous amidase reaction with both aromatic and aliphatic substrates, whereas the esterase activity was not significantly affected. The mutation that resulted from the directed evolution experiments was not in the direct vicinity of the active site but affected the substrate binding through a π–π stacking network.
Interplay of α,α‐ versus α,β‐Conjugation in the Excited States and Charged Defects of Branched Oligothiophenes as Models for Dendrimeric Materials
Authors: González‐Cano Rafael C. , Saini Geeta , Jacob Josemon , López Navarrete Juan T. , Casado Juan , Ruiz Delgado M. Carmen 
Published: November 2013

AbstractThis article investigates the excited and charged states of three branched oligothiophenes with methyl–thienyl side groups as models to promote 3D arrangements. A comparison with the properties of the parent systems, linear all‐α,α‐oligothiophenes, is proposed. A wide variety of spectroscopic methods (i.e., absorption, emission, triplet–triplet transient absorption, and spectroelectrochemistry) in combination with DFT calculations have been used for this purpose. Whereas the absorption spectra are slightly blueshifted upon branching, both the emission spectra and triplet–triplet absorption spectra are moderately redshifted; this indicates a larger contribution of the β‐linked thienyl groups in the delocalization of the S1 and T1 states rather than into the S0 state. The delocalization through the α,β‐conjugated path was found to be crucial for the stabilization of the trication species in the larger branched systems, whereas the linear sexithiophene homologue can only be stabilized up to the dication species.
Social Isomers of Picolines in a Small Space
Authors: Ajami Dariush , Theodorakopoulos Giannoula , Petsalakis Ioannis D. , Rebek Julius 
Published: November 2013

AbstractEncapsulation complexes permit the observation of molecules under conditions of limited motion. Inside capsules, molecular encounters are prolonged, prearranged, and protected from the medium, in contrast to the short‐lived and random encounters that occur in bulk solution. Herein, the interaction of α‐, β‐, and γ‐picolines in a cylindrical capsule is described. Two picolines were taken up, and NMR spectra indicated dynamic combinations of various social isomers. The stabilities of the complexes are interpreted through computational methods. The shape of the space in the capsule allowed the alignment of molecules and revealed delicate, atom‐to‐atom interactions and attractive forces that elude observation in dilute solution. These weak forces were amplified in the isolated small space of the capsule.
In Situ Formation of Semichelating Ligands: A Strategy for Tuning the Magnetic Coupling in Azide‐Bridged Copper(II) Complexes
Authors: Shi Wen‐Bo , Cui Ai‐Li , Kou Hui‐Zhong 
Published: November 2013

AbstractFive CuII complexes of trinuclear [Cu3(L1)2(N3)6] (1), one‐dimensional chain [Cu5(L2)2(N3)10]n (2), trinuclear [Cu3(L3)2(N3)6] (3) and dinuclear [Cu2(L4)2(N3)2Cl2] (4) and [Cu2(L5)2(N3)2Cl2] (5) (L1–5=RCH2OR′, R=substituted pyrazole or imidazole, R′=Me, Et or nPr) were synthesized by the reaction of CuCl2⋅2 H2O, sodium azide with RCH2Cl in CH3OH, C2H5OH or n‐C3H7OH. The ether ligands L1 and L2 can be alternatively prepared by the alcoholysis of RCH2Cl in the presence of sodium azide, whereas the ligands L3–5 form in corresponding alcohols without azide. For complexes 1–5, the oxygen atom of the ether ligands is located at the Jahn–Teller axis of CuII with the long CuO separations of 2.377(3)–2.830(3) Å. The nitrogen atoms of bridging azides are located in the equatorial or basal planes of CuII ions, favoring strong magnetic coupling. The Cu‐Nazido‐Cu bridging angles in complexes 1–3 are 98.8(2)°–101.6(1)°, leading to ferromagnetic coupling, whereas the Cu‐Nazido‐Cu angles in complexes 4 and 5 are close to 103°, leading to antiferromagnetic coupling.
A Hierarchical Nanoporous PtCu Alloy as an Oxygen‐Reduction Reaction Electrocatalyst with High Activity and Durability
Authors: Xu Caixia , Zhang Huan , Hao Qin , Duan Huimei 
Published: November 2013

AbstractA hierarchical nanoporous (HNP) PtCu alloy was successfully fabricated by two‐step dealloying of a well‐designed PtCuAl precursor alloy combined with an annealing operation. The as‐made PtCu alloy has an interconnected hierarchical network architecture with controllable bimodal ligament/pore distributions obtained by adjusting the annealing temperature and the redealloying time. HNP‐PtCu exhibits superior specific and mass activities for the oxygen‐reduction reaction (ORR) compared with single‐modal nanoporous PtCu and commercial Pt/C catalysts. More importantly, the HNP‐PtCu alloy shows much higher structure stability with less loss of the electrochemical surface area of Pt and ORR activity upon long‐term potential scans in acid solution. The excellent electrocatalytic performance for ORR makes the HNP‐PtCu alloy attractive as efficient cathode electrocatalysts in fuel‐cell‐related technologies.
A Mesoporous Carbon‐Supported Pt Nanocatalyst for the Conversion of Lignocellulose to Sugar Alcohols
Authors: Park Dae Sung , Yun Danim , Kim Tae Yong , Baek Jayeon , Yun Yang Sik , Yi Jongheop 
Published: November 2013

AbstractThe conversion of lignocellulose is a crucial topic in the renewable and sustainable chemical industry. However, cellulose from lignocellulose is not soluble in polar solvents, and is, therefore, difficult to convert into value‐added chemicals. A strategy to overcome this drawback is the use of mesoporous carbon, which enhances the affinity between the cellulose and the catalyst through its abundant functional groups and large uniform pores. Herein, we report on the preparation of a Pt catalyst supported on a type of 3D mesoporous carbon inspired by Echinometra mathae (Pt/CNE) to enhance the interaction between the catalyst and a nonsoluble reactant. In the hydrolytic hydrogenation of cellulose, the abundant oxygen groups of CNE facilitated the access of cellulose to the surface of the catalyst, and the open pore structure permits cello‐oligomers to effectively diffuse to the active sites inside the pore. The highly dispersed Pt performed dual roles: hydrolysis by in situ generating protons from H2 or water as well as effective hydrogenation. The use of the Pt/CNE catalyst resulted in an approximately 80 % yield of hexitol, the best performance reported to date. In direct conversion of hardwood powder, the Pt/CNE shows good performance in the production of sugar alcohols (23 % yield). We expect that the open‐structured 3D carbon will be widely applied to the conversion of various lignocellulosic materials.
The effects of maternal eating disorders on offspring childhood and early adolescent psychiatric disorders
Authors: Micali Nadia , De Stavola Bianca , Ploubidis George B , Simonoff Emily , Treasure Janet 
Published: November 2013

ABSTRACTObjectiveThere is evidence that parental psychiatric disorders are associated with offspring psychiatric disorder. Very few small studies have investigated the effect of maternal eating disorders on offspring psychopathology throughout childhood and early adolescence. We aimed to investigate psychiatric disorders at age 7, 10, and 13 years in offspring of women with eating disorders prior to pregnancy and investigate the relative contribution of other psychiatric disorders.MethodWomen (N = 12,035) from a large population‐based longitudinal cohort: the Avon Longitudinal Study of Parents and Children (ALSPAC). A brief prepregnancy psychiatric history was obtained at enrollment to determine exposure. Offspring psychiatric disorder was measured using the developmental and well‐being assessment at ages 7, 10, and 13.ResultsMaternal eating disorders were associated with a psychiatric diagnosis in the offspring at age 7 and 10, particularly emotional disorders (Odds ratio = 1.9, 95%CI: 1.1–2.8). Maternal psychiatric disorders other than eating disorders predicted psychiatric diagnoses across ages, and acted in an additive fashion with maternal eating disorders.DiscussionMaternal eating disorders together with comorbid psychopathology increase risk for psychiatric disorders in childhood and early adolescence, in particular for emotional disorders. This has important implications for prevention and future research. © 2013 Wiley Periodicals, Inc. (Int J Eat Disord 2014; 47:385–393)
Predicting grey‐sided vole occurrence in northern Sweden at multiple spatial scales
Authors: Magnusson Magnus , Bergsten Arvid , Ecke Frauke , Bodin Örjan , Bodin Lennart , Hörnfeldt Birger 
Published: November 2013

AbstractForestry is continually changing the habitats for many forest‐dwelling species around the world. The grey‐sided vole (Myodes rufocanus) has declined since the 1970s in forests of northern Sweden. Previous studies suggested that this might partly be caused by reduced focal forest patch size due to clear‐cutting. Proximity and access to old pine forest and that microhabitats often contains stones have also been suggested previously but never been evaluated at multiple spatial scales. In a field study in 2010–2011 in northern Sweden, we investigated whether occurrence of grey‐sided voles would be higher in (1) large focal patches of >60 years old forest, (2) in patches with high connectivity to surrounding patches, and (3) in patches in proximity to stone fields. We trapped animals in forest patches in two study areas (Västerbotten and Norrbotten). At each trap station, we surveyed structural microhabitat characteristics. Landscape‐scale features were investigated using satellite‐based forest data combined with geological maps. Unexpectedly, the vole was almost completely absent in Norrbotten. The trap sites in Norrbotten had a considerably lower amount of stone holes compared with sites with voles in Västerbotten. We suggest this might help to explain the absence in Norrbotten. In Västerbotten, the distance from forest patches with voles to stone fields was significantly shorter than from patches without voles. In addition, connectivity to surrounding patches and size of the focal forest patches was indeed related to the occurrence of grey‐sided voles, with connectivity being the overall best predictor. Our results support previous findings on the importance of large forest patches, but also highlight the importance of connectivity for occurrence of grey‐sided voles. The results further suggest that proximity to stone fields increase habitat quality of the forests for the vole and that the presence of stone fields enhances the voles' ability to move between nearby forest patches through the matrix.