bluuebunny/crossref_metadata_2025_split huggingface dataset:
Periodic variations of oxygen EUV dayglow in the upper atmosphere of Venus: Hisaki/EXCEED observations
Authors: Masunaga K. , Seki K. , Terada N. , Tsuchiya F. , Kimura T. , Yoshioka K. , Murakami G. , Yamazaki A. , Kagitani M. , Tao C. , Fedorov A. , Futaana Y. , Zhang T. L. , Shiota D. , Leblanc F. , Chaufray J.‐Y. , Yoshikawa I. 
Published: October 2015

AbstractUsing the Extreme Ultraviolet Spectroscope for Exospheric Dynamics (EXCEED) aboard Hisaki and the Solar Extreme Ultraviolet Monitor on the Solar and Heliospheric Observatory, we investigate variations of the extreme ultraviolet (EUV) dayglow brightness for OII 83.4 nm, OI 130.4 nm, and OI 135.6 nm in the Venusian upper atmosphere observed in March–April (period 1), April–May (period 2), and June–July (period 3) in 2014. The result shows that characteristic periodicities exist in the dayglow variations other than the ~27 day solar rotational effect of the solar EUV flux: 1.8, 2.8, 3.1, 4.5, and 9.9 day in period 1; 1.1 day in period 2; and 1.0 and 11 day in period 3. Many of these periodicities are consistent with previous observations and theory. We suggest these periodicities are related to density oscillations of oxygen atoms or photoelectrons in the thermosphere. The cause of these periodicities is still uncertain, but planetary‐scale waves and/or gravity waves propagating from the middle atmosphere, and/or minor periodic variations of the solar EUV radiation flux may play a role. Effects of the solar wind parameters (velocity, dynamic pressure, and interplanetary magnetic field's intensity) on the dayglow variations are also investigated using the Analyser of Space Plasma and Energetic Atoms (ASPERA‐4) and magnetometer aboard Venus Express. Although clear correlation with the dayglow variations is not found, their minor periodicities are similar to the dayglow periodicities. Contribution of the solar wind to the dayglow remains still unknown, but the solar wind parameters might affect the dayglow variations.
Reaction‐Based Mechanistic Investigations of Asymmetric Hetero‐Diels–Alder Reactions of Enones with Isatins Catalyzed by Amine‐Based Three‐Component Catalyst Systems
Authors: Cui Hai‐Lei , Chouthaiwale Pandurang V. , Yin Feng , Tanaka Fujie 
Published: October 2015

AbstractReaction‐based mechanistic investigations were performed for the hetero‐Diels–Alder (hDA) reactions of enones with isatins that were catalyzed by an amine‐based catalyst system composed of three molecules (an amine, an acid, and a thiourea). The results indicated that the hDA product obtained from the reaction between hept‐3‐en‐2‐one and isatin using the amine‐based catalyst system was generated via a kinetically controlled [4+2] cycloaddition reaction of the in situ‐generated enamine of the enone as the diene and isatin as the dienophile. The amine of the three‐component catalyst system was essential for the catalysis and stereocontrol, but the other components of the catalyst system also played important roles. Based on the results, plausible transition states are discussed, and the system was further improved by altering the loadings of the catalyst components for faster reactions with high stereoselectivities. The three‐component catalyst systems are flexible and can be tuned to obtain better results.
A High‐Valent Iron(IV) Peroxo Core Derived from O2
Authors: Kishima Takahiro , Matsumoto Takahiro , Nakai Hidetaka , Hayami Shinya , Ohta Takehiro , Ogo Seiji 
Published: October 2015

AbstractDioxygen‐tolerant [NiFe] hydrogenases catalyze not only the conversion of H2 into 2 H+ and 2 e− but also the reduction of O2 to H2O. Chemists have sought to mimic such bifunctional catalysts with structurally simpler compounds to facilitate analysis and improvement. Herein, we report a new [NiFe]‐based catalyst for O2 reduction via an O2 adduct. Structural investigations reveal the first example of a side‐on iron(IV) peroxo complex.
Isolation of Elusive HAsAsH in a Crystalline Diuranium(IV) Complex
Authors: Gardner Benedict M. , Balázs Gábor , Scheer Manfred , Wooles Ashley J. , Tuna Floriana , McInnes Eric J. L. , McMaster Jonathan , Lewis William , Blake Alexander J. , Liddle Stephen T. 
Published: October 2015

AbstractThe HAsAsH molecule has hitherto only been proposed tentatively as a short‐lived species generated in electrochemical or microwave‐plasma experiments. After two centuries of inconclusive or disproven claims of HAsAsH formation in the condensed phase, we report the isolation and structural authentication of HAsAsH in the diuranium(IV) complex [{U(TrenTIPS)}2(μ‐η2:η2‐As2H2)] (3, TrenTIPS=N(CH2CH2NSiPri3)3; Pri=CH(CH3)2). Complex 3 was prepared by deprotonation and oxidative homocoupling of an arsenide precursor. Characterization and computational data are consistent with back‐bonding‐type interactions from uranium to the HAsAsH π*‐orbital. This experimentally confirms the theoretically predicted excellent π‐acceptor character of HAsAsH, and is tantamount to full reduction to the diarsane‐1,2‐diide form.
Creating Reactivity with Unstable Endmembers using Pressure and Temperature: Synthesis of Bulk Cubic Mg0.4Fe0.6N
Authors: Serghiou George , Ji Gang , Odling Nicholas , Reichmann Hans J. , Morniroli Jean‐Paul , Boehler Reinhard , Frost Dan J. , Wright Jonathan P. , Wunder Bernd 
Published: October 2015

AbstractAlloy and nitride solid solutions are prominent for structural, energy and information processing applications. There are frequently however barriers to making them. We remove barriers to reactivity here using pressure with a new synthetic approach. We target pressures where the reasons for cubic endmember nitride instability can become the driving force for cubic nitride solid solution stability. Using this approach we form a novel rocksalt Mg0.4Fe0.6N solid solution at between 15 and 23 GPa and up to 2500 K. This is a system where, neither an alloy nor a nitride solid solution form at ambient conditions and bulk MgN and FeN endmembers do not form, either at ambient or at high pressure. The new nitride is formed, by removing endmember lattice mismatch with pressure, allowing a stabilizing redistribution of valence electrons upon heating. This approach can be employed for a range of normally unreactive systems. Mg, Fe and enhanced nitrogen presence, may also indicate a richer reaction chemistry in our planets interior.
Synthesis of Atomically Thin Boron Films on Copper Foils
Authors: Tai Guoan , Hu Tingsong , Zhou Yungang , Wang Xufeng , Kong Jizhou , Zeng Tian , You Yuncheng , Wang Qin 
Published: October 2015

AbstractTwo‐dimensional boron materials have recently attracted extensive theoretical interest because of their exceptional structural complexity and remarkable physical and chemical properties. However, such 2D boron monolayers have still not been synthesized. In this report, the synthesis of atomically thin 2D γ‐boron films on copper foils is achieved by chemical vapor deposition using a mixture of pure boron and boron oxide powders as the boron source and hydrogen gas as the carrier gas. Strikingly, the optical band gap of the boron film was measured to be around 2.25 eV, which is close to the value (2.07 eV) determined by first‐principles calculations, suggesting that the γ‐B28 monolayer is a fascinating direct band gap semiconductor. Furthermore, a strong photoluminescence emission band was observed at approximately 626 nm, which is again due to the direct band gap. This study could pave the way for applications of two‐dimensional boron materials in electronic and photonic devices.
Aquation Is a Crucial Activation Step for Anticancer Action of Ruthenium(II) Polypyridyl Complexes to Trigger Cancer Cell Apoptosis
Authors: Li Meng , Lai Lanhai , Zhao Zhennan , Chen Tianfeng 
Published: October 2015

AbstractAquation has been proposed as crucial chemical action step for ruthenium (Ru) complexes, but its effects on the action mechanisms remain elusive. Herein, we have demonstrated the aquation process of a potent Ru polypyridyl complex (RuBmp=[RuII(bmbp)(phen)Cl]ClO4, bmbp=2,6‐bis(6‐methylbenzimidazol‐2‐yl) pyridine, phen=phenanthroline) with a chloride ligand, and revealed that aquation of RuBmp effectively enhanced its hydrophilicity and cellular uptake, thus significantly increasing its anticancer efficacy. The aquation products (H‐RuBmp=[RuII(bmbp)(phen)Cl]ClO4, [RuII(bmbp)(phen)(H2O)]ClO4, bmbp) exhibited a much higher apoptosis‐inducing ability than the intact complex, with involvement of caspase activation, mitochondria dysfunction, and interaction with cell membrane death receptors. H‐RuBmp demonstrated a higher interaction potency with the cell membrane and induced higher levels of ROS overproduction in cancer cells to regulate the AKT, MAPK, and p53 signaling pathways. Taken together, this study could provide useful information for fine‐tuning the rational design of next‐generation metal medicines.
Evaluation of Pseudoenantiomeric Mixed Carbonates as Efficient Fluorogenic Probes for Enantioselectivity Screening
Authors: Zadlo Anna , Koszelewski Dominik , Borys Filip , Ostaszewski Ryszard 
Published: October 2015

AbstractWe report mixed carbonates as enzyme substrates and demonstrate their application as fluorogenic probes for lipase and esterase enantiopreference screening. By the application of pseudoenantiomers with distinct fluorescence behaviors, it is possible to evaluate the activity and enantiopreference of hydrolytic enzymes. In order to validate our method, enantioselectivities calculated from fluorometric measurements were compared with the results obtained from larger‐scale kinetic resolution.
Mitochondrial superoxide dismutase deficiency accelerates chronological aging in the fission yeast Schizosaccharomyces pombe
Authors: Ogata Toshiya , Senoo Takanori , Kawano Shinji , Ikeda Shogo 
Published: October 2015

AbstractA mitochondrial superoxide dismutase (SOD2) is the first line of antioxidant defense against mitochondrial superoxide. Even though the involvement of SOD2 in lifespan has been studied extensively in several organisms, characterization of the aging process has not been performed for the sod2 mutant (sod2Δ) of a prominent model Schizosaccharomyces pombe. In this study, we measured the chronological lifespan of sod2Δ cells by their ability to survive in long‐term culture. SOD2 deficiency drastically decreased cell viability in the stationary phase. The mutation frequency of nuclear DNA in sod2Δ was elevated in the stationary phase, and cellular proteins and nuclear DNA were extensively degraded, concurrent with cell death. The sod2 gene in wild‐type cells could be induced by an increase in endogenous oxidative stresses, after which, SOD2 activity was substantially elevated during the stationary phase. Culture in a lower glucose concentration (calorie restriction) prominently extended the sod2Δ lifespan. Therefore, S. pombe SOD2 plays a critical role in longevity through its upregulation in the non‐dividing phase.
Chemodivergent Palladium‐Catalyzed Processes: Role of Versatile Ligands
Authors: Nava Paola , Clavier Hervé , Gimbert Yves , Giordano Laurent , Buono Gérard , Humbel Stéphane 
Published: October 2015

AbstractWhereas the reaction of norbornadiene with terminal alkynes in the presence of a phosphapalladacycle catalyst leads to the formation of hydroalkynation products, the use of phosphinous acid–phosphinito‐containing palladium complexes gives rise to formal [2+1] cycloadducts. An experimental and computational approach was employed to study the mechanisms of the palladium‐promoted hydroalkynation and [2+1] cycloaddition. On the one hand, experiments highlight the crucial role of acidolysis steps on the catalytic activities. On the other hand, DFT calculations demonstrate the specificity of the phosphinito–phosphinous acid ligands, that is, the non‐equivalence of the two phosphorus atoms but the interchangeability of their properties. These results may have important implications for the mechanism of other palladium‐catalyzed transformations especially those involving phosphapalladacycles and phosphinous acid–phosphinito‐containing palladium complexes.
Effects of Anxiety and Depression on Arterial Elasticity of Subjects With Suboptimal Physical Health
Authors: Sun Ningling , Xi Yang , Zhu Zhiming , Yin Huijun , Tao Qiushan , Wang Hongyi , Wang Luyan , Ma Zhiyi , Chen Yuanyuan , Yao Dan 
Published: October 2015

ABSTRACTBackgroundThe authors investigated the effects of suboptimal health status (SHS; high‐normal blood pressure, blood glucose, and blood lipids) on arterial elasticity in subjects with or without anxiety or depression.HypothesisSuboptimal physical health status and anxiety or depression increase the risk of cardiovascular diseases.MethodsThis was a cross‐sectional, observational, multicenter study. Among 1520 subjects who underwent physical examination between May 2009 and December 2012 in Beijing and Chongqing, China, 955 were included. All subjects completed anxiety and depression questionnaires. Systemic vascular compliance (SVC), systemic vascular resistance, and brachial artery distensibility (BAD) were measured during arterial elasticity evaluation.ResultsOf 955 participants, 633 were classified as having SHS and 322 were classified as healthy. Systemic vascular compliance and BAD were worse in SHS subjects than in healthy subjects (SVC: 1.23 ± 0.22 vs 1.29 ± 0.25 mL/mm Hg; BAD: 6.26 ± 1.32 vs 6.61 ± 1.24%/mm Hg, respectively; both P < 0.05). Of 955 subjects, 37.7% and 43.9% had anxiety and depression, respectively. Systemic vascular compliance and BAD in SHS subjects with concomitant anxiety or depression were significantly lower than in SHS subjects without anxiety or depression (SVC: 1.22 ± 0.23 vs 1.23 ± 0.20 mL/mm Hg; BAD: 6.10 ± 1.36 vs 6.33 ± 1.20 %/mm Hg, respectively; both P < 0.05) and even lower than in healthy subjects.ConclusionsThough anxiety and depression had less impact on arterial elasticity in a healthy population, they may be involved in pathogenesis of vascular damage in the population with SHS.
Numerical modeling of fluid–structure interaction in arteries with anisotropic polyconvex hyperelastic and anisotropic viscoelastic material models at finite strains
Authors: Balzani Daniel , Deparis Simone , Fausten Simon , Forti Davide , Heinlein Alexander , Klawonn Axel , Quarteroni Alfio , Rheinbach Oliver , Schröder Joerg 
Published: October 2015

SummaryThe accurate prediction of transmural stresses in arterial walls requires on the one hand robust and efficient numerical schemes for the solution of boundary value problems including fluid–structure interactions and on the other hand the use of a material model for the vessel wall that is able to capture the relevant features of the material behavior. One of the main contributions of this paper is the application of a highly nonlinear, polyconvex anisotropic structural model for the solid in the context of fluid–structure interaction, together with a suitable discretization. Additionally, the influence of viscoelasticity is investigated. The fluid–structure interaction problem is solved using a monolithic approach; that is, the nonlinear system is solved (after time and space discretizations) as a whole without splitting among its components. The linearized block systems are solved iteratively using parallel domain decomposition preconditioners. A simple – but nonsymmetric – curved geometry is proposed that is demonstrated to be suitable as a benchmark testbed for fluid–structure interaction simulations in biomechanics where nonlinear structural models are used. Based on the curved benchmark geometry, the influence of different material models, spatial discretizations, and meshes of varying refinement is investigated. It turns out that often‐used standard displacement elements with linear shape functions are not sufficient to provide good approximations of the arterial wall stresses, whereas for standard displacement elements or F‐bar formulations with quadratic shape functions, suitable results are obtained. For the time discretization, a second‐order backward differentiation formula scheme is used. It is shown that the curved geometry enables the analysis of non‐rotationally symmetric distributions of the mechanical fields. For instance, the maximal shear stresses in the fluid–structure interface are found to be higher in the inner curve that corresponds to clinical observations indicating a high plaque nucleation probability at such locations. Copyright © 2015 John Wiley & Sons, Ltd.
Atomic Layer Deposition of a Particularized Protective MgF2 Film on a Li‐Ion Battery LiMn1.5Ni0.5O4 Cathode Powder Material
Authors: Kraytsberg Alexander , Drezner Haika , Auinat Mahmud , Shapira Alon , Solomatin Nickolay , Axmann Peter , Wohlfahrt‐Mehrens Margret , Ein‐Eli Yair 
Published: October 2015

AbstractA several atomic layers thick magnesium fluoride (MgF2) film is successfully deposited onto each individual grain of an ultrahigh‐potential LiMn1.5Ni0.5O4‐powder material for Li‐ion batteries. The resulting film has a marked protection action, as it does not compromise the cathode performance substantially, while it extends the cycle life of the cathodes prepared from the coated powder. The protective effect is pronounced at 45 °C and the catastrophic capacity fading is halted. The essence of the protecting action is suggested to be in blocking the access of aggressive electrolyte‐decomposition byproducts to the cathode material surface.
Highly Efficient Polymer‐Supported Catalytic System for the Valorization of Carbon Dioxide
Authors: Desens Willi , Kohrt Christina , Frank Marcus , Werner Thomas 
Published: October 2015

AbstractPolydibenzo‐18‐crown‐6 was utilized as a co‐catalyst and polymeric support in combination with potassium iodide for the synthesis of cyclic carbonates from carbon dioxide and epoxides under mild and solvent‐free conditions. The efficiency of this catalytic system can be easily increased by loading the polymer with KI prior to the reaction. The influence of various reaction parameters were studied thoroughly. The scope and limitation of the catalyst system was studied at 80 °C and 100 °C. A large number of terminal epoxides (14) were converted to the desired cyclic carbonates in yields up to 99 %. We could successfully recover and reuse the catalyst >20 times with excellent yields up to 99 %. Although, we observed that the activity gradually decreased after repetitive cycles. This decrease was attributed to KI leaching and partial degradation caused by mechanical stirring. This assumption is supported by scanning electron microscopy and energy dispersive X‐ray spectroscopy.
Intramolecular C–O Insertion of a Germanium(II) Salicyl Alcoholate: A Combined Experimental and Theoretical Study
Authors: Kitschke Philipp , Rüffer Tobias , Korb Marcus , Lang Heinrich , Schneider Wolfgang B. , Auer Alexander A. , Mehring Michael 
Published: October 2015

AbstractThe synthesis of germanium(II) 2‐tert‐butyl‐4‐methyl‐6‐(oxidomethyl)phenolate (1) starting from Ge[N(SiMe3)2]2 and the corresponding salicyl alcohol is reported. Compound 1 undergoes an intramolecular oxidative insertion reaction of germanium into a C–O bond to result in a cyclic germanium(IV) tetraoxidogermocane (2). Addition of 3‐tert‐butyl‐2‐hydroxy‐5‐methylbenzyl alcohol to either compound 1 or 2 gave a spirocyclic monoorgano dioxagermine (3). The results of 1H NMR spectroscopic studies and DFT‐D calculations are in agreement with the proposed reaction cascade in which the novel germylene 1 is first converted into the germocane 2 followed by reaction with 3‐tert‐butyl‐2‐hydroxy‐5‐methylbenzyl alcohol to finally provide compound 3. Addition of 4‐(dimethylamino)pyridine to a solution of germylene 1 resulted in the formation of an air‐stable monomeric 1:1 complex (4). The characterization of compounds 1–4 by single‐crystal X‐ray diffraction analysis, thermal analysis, and 1H NMR, 13C{1H} NMR, and ATR‐FTIR spectroscopy is presented.
A micromorphological record of contemporary and relict pedogenic processes in soils of the Indo‐Gangetic Plains: implications for mineral weathering, provenance and climatic changes
Authors: Srivastava Pankaj , Aruche Manini , Arya Ajay , Pal Dilip K. , Singh Lalan P. 
Published: October 2015

AbstractMicromorphology has important application in earth surface process and landform studies particularly in alluvial settings such as the Indo‐Gangetic Plains (IGP) with different geomorphic surfaces to identify climatic changes and neotectonic events and their influence on pedogenesis. The soils of the IGP extending from arid upland in the west to per humid deltaic plains in the east developed on five geomorphic surfaces namely QIG1 to QIG5 originating during the last 13.5 ka. Four soil‐geomorphic systems across the entire IGP are identified as: (i) the western Yamuna Plains/Uplands, (ii) the Yamuna‐Ganga Interfluve, (iii) the Ganga‐Ghaghara Interfluve, and (iv) the Deltaic Plains.Thin section analysis of the soils across the four soil‐geomorphic systems provides a record of provenance, mineral weathering, pedogenic processes and polygenesis in IGP. The soils over major parts of the IGP dominantly contain muscovite and quartz and small fraction of highly altered feldspar derived from the Himalayas. However, soils in the western and eastern parts of the IGP contain large volumes of fresh to weakly altered plagioclase and smectitic clay derived from the Indian craton. The soils in western Yamuna Plains/Uplands dominated by QIG2–QIG3 geomorphic surfaces and pedogenic carbonate developed in semi‐arid climate prior to 5 ka. However, soils of the central part of the IGP in the Yamuna‐Ganga Interfluve and Ganga‐Ghaghara Interfluve regions with dominance of QIG4–QIG5 surfaces are polygenetic due to climate change over the last 13.5 ka. The clay pedofeatures formed during earlier wet phase (13.5–11 ka) show degradation, loss of preferred orientation, speckled appearance in contrast with the later phase of wet climate (6.5–4 ka). The soils over the deltaic plains with dominance of vertic features along with clay pedofeatures suggest that illuviation of fine clay is an important pedogenic process even in soils with shrink‐swell characteristics. Copyright © 2015 John Wiley & Sons, Ltd.
Two-generational effects of contaminants in Daphnia magna: Effects of offspring quality
Authors: Campos Bruno , Jordão Rita , Rivetti Claudia , Lemos M.F.L. , Soares A.M.V.M. , Tauler Roma , Barata Carlos 
Published: October 2015

Abstract

The authors set up a protocol to perform a 2-generational ring test using the existing guidelines for the Daphnia magna reproduction test. It is well known in ecology that size and quality of offspring vary across the first clutches in D. magna and that certain chemicals affect offspring quality. Therefore, the origin of the second generation is an important factor to consider. Two-generational effects across first, second, and third clutches were evaluated using 4-nonylphenol; those across first and third clutches were evaluated using tributyltin, and those across the third clutch were evaluated using piperonyl butoxide. The compound showing the greatest aggravation of toxic effects between the parental and second generations was piperonyl butoxide, followed by 4-nonylphenol, whereas intergenerational effects of tributyltin varied across experiments. The studied chemicals affected the quantity and quality of the offspring produced by exposed females of the parental generation, those effects being greater in third-clutch neonates. Therefore, when third-clutch offspring were further exposed, they turned out to be more sensitive than the parental generation. The results are in line with those obtained in multigenerational studies using mammalian tests, which showed that, in many cases, effects on the second generation can be predicted by evaluating the quality of the offspring produced. Environ Toxicol Chem 2016;35:1470–1477. © 2015 SETAC