bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal coordination method of opportunistic array radars for multi‐target‐tracking‐based radio frequency stealth in clutter
Authors: Zhang Zhenkai , Salous Sana , Li Hailin , Tian Yubo 
Published: October 2015

AbstractOpportunistic array radar is a new radar system that can improve the modern radar performance effectively. In order to improve its radio frequency stealth ability, a novel coordination method of opportunistic array radars in the network for target tracking in clutter is presented. First, the database of radar cross section for targets is built, then the signal‐to‐noise ratio for netted radars is computed according to the radar cross section and range of target. Then the joint probabilistic data association algorithm of tracking is improved with consideration of emitted power of the opportunistic array radar, which has a main impact on detection probability for tracking in clutter. Finally, with the help of grey relational grade and covariance control, the opportunistic array radar with the minimum radiated power will be selected for better radio frequency stealth performance. Simulation results show that the proposed algorithm not only has excellent tracking accuracy in clutter but also saves much more radiated power comparing with other methods.
A General Strategy for the Separation of Immiscible Organic Liquids by Manipulating the Surface Tensions of Nanofibrous Membranes
Authors: Wang Li , Zhao Yong , Tian Ye , Jiang Lei 
Published: October 2015

AbstractOil/water separation membranes with different wettability towards water are attractive for their economic efficiency and convenience. The key factor for the separation process is the roughness‐enhanced wettability of membranes based on the intrinsic wetting threshold (IWT) of water, that is, the limitation of the wettability caused by hydrophobicity and hydrophilicity. However, the separation of organic liquids (OLs) remains a challenge. Herein, we manipulate the surface tensions of nanofibrous membranes to lie between the IWTs of the two OLs to be separated so that the nanofibrous membranes can be endowed with superlyophobicity and superlyophilicity for the two liquids, and thus lead to successful separation. Our investigations provide a general strategy to separate any immiscible liquids efficiently, and may lead to the development of membranes with a large capacity, high flux, and high selectivity for organic reactions or liquid extraction in chemical engineering.
Cuprous Oxide Catalyzed Oxidative CC Bond Cleavage for CN Bond Formation: Synthesis of Cyclic Imides from Ketones and Amines
Authors: Wang Min , Lu Jianmin , Ma Jiping , Zhang Zhe , Wang Feng 
Published: October 2015

AbstractSelective oxidative cleavage of a CC bond offers a straightforward method to functionalize organic skeletons. Reported herein is the oxidative CC bond cleavage of ketone for CN bond formation over a cuprous oxide catalyst with molecular oxygen as the oxidant. A wide range of ketones and amines are converted into cyclic imides with moderate to excellent yields. In‐depth studies show that both α‐CH and β‐CH bonds adjacent to the carbonyl groups are indispensable for the CC bond cleavage. DFT calculations indicate the reaction is initiated with the oxidation of the α‐CH bond. Amines lower the activation energy of the CC bond cleavage, and thus promote the reaction. New insight into the CC bond cleavage mechanism is presented.
Splitting a Substrate into Three Parts: Gold‐Catalyzed Nitrogenation of Alkynes by CC and CC Bond Cleavage
Authors: Qin Chong , Su Yijin , Shen Tao , Shi Xiaodong , Jiao Ning 
Published: October 2015

AbstractA gold‐catalyzed nitrogenation of alkynes for the synthesis of carbamides and amino tetrazoles through CC and CC bond cleavages is described. A diverse set of functionalized carbamide and amino tetrazole derivatives were selectively constructed under mild conditions. The chemoselectivity can be easily switched by the selection of the acid additives. The reaction is characterized by its broad substrate scope, direct construction of high value products, easy operation under air, and mild conditions at room temperature. This chemistry provides a way to transform alkynes by splitting the substrate into three parts.
Total Synthesis of (+)‐MPC1001B
Authors: Kurogi Taichi , Okaya Shun , Fujiwara Hideto , Okano Kentaro , Tokuyama Hidetoshi 
Published: October 2015

AbstractThe first total synthesis of an epidithiodiketopiperazine alkaloid, (+)‐MPC1001B, was accomplished. This synthesis features a tetra‐n‐butylammonium fluoride mediated intramolecular aldol reaction for forming the 15‐membered macrolactone ring, and the construction of an epidithiodiketopiperazine substructure through a stepwise sulfenylation reaction involving a novel trityl trisulfide (TrSSS)‐group transfer.
Regioselective Synthesis and Characterization of Multinuclear Convex‐Bound Ruthenium‐[n]Cycloparaphenylene (n=5 and 6) Complexes
Authors: Kayahara Eiichi , Patel Vijay Kumar , Mercier Audrey , Kündig E. Peter , Yamago Shigeru 
Published: October 2015

AbstractMono‐ and multinuclear complexes of ruthenium and [n]cycloparaphenylene (CPP, n=5 and 6) were synthesized in excellent yields through ligand exchange of the cationic complex [(Cp)Ru(CH3CN)3](PF6) with CPP. In the multinuclear complexes, ruthenium selectively coordinated to alternate paraphenylene units to give bis‐ and tris‐coordinated Ru complexes for [5] and [6]CPPs, respectively. Single‐crystal X‐ray analysis revealed the Ru was coordinated with η6‐hapticity on the convex surface of CPP.
Immobilization of enzymes using non‐ionic colloidal liquid aphrons (CLAs): Activity kinetics, conformation, and energetics
Authors: Ward Keeran , Xi Jingshu , Stuckey David C. 
Published: October 2015

ABSTRACTThis study seeks to examine the ability of non‐ionic/non‐polar Colloidial Liquid Aphrons (CLAs) to preserve enzyme functionality upon immobilization and release. CLAs consisting of micron‐sized oil droplets surrounded by a thin aqueous layer stabilized by a mixture of surfactants, were formulated by direct addition (pre‐manufacture addition) using 1% Tween 80/mineral oil and 1% Tween 20 and the enzymes lipase, aprotinin and α‐chymotrypsin. The results of activity assays for both lipase and α‐chymotrypsin showed that kinetic activity increased upon immobilization by factors of 7 and 5.5, respectively, while aprotinin retained approximately 85% of its native activity. The conformation of the enzymes released through desorption showed no significant alterations compared to their native state. Changes in pH and temperature showed that optimum conditions did not change after immobilization, while analysis of activation energy for the immobilized enzyme showed an increase in activity at higher temperatures. Furthermore, the effect of bound water within the aphron structure allowed for some degree of enzyme hydration, and this hydration was needed for an active conformation with results showing a decrease in ΔH* for the immobilized system compared to its native counterpart. Biotechnol. Bioeng. 2016;113: 970–978. © 2015 Wiley Periodicals, Inc.
Synthesis of Nickel Nanoparticles with N‐Doped Graphene Shells for Catalytic Reduction Reactions
Authors: Pisiewicz Sabine , Formenti Dario , Surkus Annette‐Enrica , Pohl Marga‐Martina , Radnik Jörg , Junge Kathrin , Topf Christoph , Bachmann Stephan , Scalone Michelangelo , Beller Matthias 
Published: October 2015

AbstractThe synthesis of novel nanoparticles is of general importance for the development of efficient heterogeneous catalysts. Herein, the preparation of carbon‐supported nickel‐based nanoparticles (NPs), modified by nitrogen‐doped graphene layers, is reported for the first time. The resulting materials were characterized in detail by TEM, X‐ray photoelectron spectroscopy (XPS), XRD, elemental analysis (EA), electron paramagnetic resonance (EPR), temperature‐programmed reduction (TPR), BET, and Raman analysis. Initial catalytic tests revealed the potential of this class of compounds in hydrogenation reactions.
Mesomeric Effects of Graphene Modified with Diazonium Salts: Substituent Type and Position Influence its Properties
Authors: Bouša Daniel , Jankovský Ondřej , Sedmidubský David , Luxa Jan , Šturala Jiří , Pumera Martin , Sofer Zdeněk 
Published: October 2015

AbstractIn the last decade, graphene and graphene derivatives have become some of the most intensively studied materials. Tuning of the electronic and electrochemical properties of graphene is of paramount importance. In this study, six diazonium‐modified graphenes containing different functional groups according to the diazonium salt precursor were investigated. These diazonium moieties have a strong mesomeric (resonance) effect and act as either electron‐donating or ‐withdrawing species. Different graphene precursors, such as thermally and chemically reduced graphenes were studied. All the products were characterized in detail by elemental combustion analysis, FTIR spectroscopy, Raman spectroscopy, high‐resolution X‐ray photoelectron spectroscopy (XPS), and cyclic voltammetry. Resistivity and zeta potential measurements were consistent with theoretical (DFT) calculations. The results show that chemical modification of graphene by diazotation strongly influences its properties, creating a huge application potential in microelectronics, energy storage and conversion devices, and electrocatalysis.
Chiral Lithiated Allylic α‐Sulfonyl Carbanions: Experimental and Computational Study of Their Structure, Configurational Stability, and Enantioselective Synthesis
Authors: Gerhards Frank , Griebel Nicole , Runsink Jan , Raabe Gerhard , Gais Hans‐Joachim 
Published: October 2015

AbstractX‐ray crystal structure analysis of the lithiated allylic α‐sulfonyl carbanions [CH2CHC(Me)SO2Ph]Li⋅diglyme, [cC6H8SO2tBu]Li⋅PMDETA and [cC7H10SO2tBu]Li⋅PMDETA showed dimeric and monomeric CIPs, having nearly planar anionic C atoms, only OLi bonds, almost planar allylic units with strong CC bond length alternation and the s‐trans conformation around C1C2. They adopt a C1S conformation, which is similar to the one generally found for alkyl and aryl substituted α‐sulfonyl carbanions. Cryoscopy of [EtCHCHC(Et)SO2tBu]Li in THF at 164 K revealed an equilibrium between monomers and dimers in a ratio of 83:17, which is similar to the one found by low temperature NMR spectroscopy. According to NMR spectroscopy the lone‐pair orbital at C1 strongly interacts with the CC double bond. Low temperature 6Li,1H NOE experiments of [EtCHCHC(Et)SO2tBu]Li in THF point to an equilibrium between monomeric CIPs having only OLi bonds and CIPs having both OLi and C1Li bonds. Ab initio calculation of [MeCHCHC(Me)SO2Me]Li⋅(Me2O)2 gave three isomeric CIPs having the s‐trans conformation and three isomeric CIPs having the s‐cis conformation around the C1C2 bond. All s‐trans isomers are more stable than the s‐cis isomers. At all levels of theory the s‐trans isomer having OLi and C1Li bonds is the most stable one followed by the isomer which has two OLi bonds. The allylic unit of the C,O,Li isomer shows strong bond length alternation and the C1 atom is in contrast to the O,Li isomer significantly pyramidalized. According to NBO analysis of the s‐trans and s‐cis isomers, the interaction of the lone pair at C1 with the π* orbital of the CC double bond is energetically much more favorable than that with the “empty” orbitals at the Li atom. The C1S and C1C2 conformations are determined by the stereoelectronic effects nC–σSR* interaction and allylic conjugation. 1H DNMR spectroscopy of racemic [EtCHCHC(Et)SO2tBu]Li, [iPrCHCHC(iPr)SO2tBu]Li and [EtCHC(Me)C(Et)SO2tBu]Li in [D8]THF gave estimated barriers of enantiomerization of ΔG≠=13.2 kcal mol−1 (270 K), 14.2 kcal mol−1 (291 K) and 14.2 kcal mol−1 (295 K), respectively. Deprotonation of sulfone (R)‐EtCHCHCH(Et)SO2tBu (94 % ee) with nBuLi in THF at −105 °C occurred with a calculated enantioselectivity of 93 % ee and gave carbanion (M)‐[EtCHCHC(Et)SO2tBu]Li, the deuteration and alkylation of which with CF3CO2D and MeOCH2I, respectively, proceeded with high enantioselectivities. Time‐dependent deuteration of the enantioenriched carbanion (M)‐[EtCHCHC(Et)SO2tBu]Li in THF gave a racemization barrier of ΔG≠=12.5 kcal mol−1 (168 K), which translates to a calculated half‐time of racemization of t1/2=12 min at −105 °C.
Intramolecular OH⋅⋅⋅Fluorine Hydrogen Bonding in Saturated, Acyclic Fluorohydrins: The γ‐Fluoropropanol Motif
Authors: Linclau Bruno , Peron Florent , Bogdan Elena , Wells Neil , Wang Zhong , Compain Guillaume , Fontenelle Clement Q. , Galland Nicolas , Le Questel Jean‐Yves , Graton Jérôme 
Published: October 2015

AbstractFluorination is commonly exercised in compound property optimization. However, the influence of fluorination on hydrogen‐bond (HB) properties of adjacent functional groups, as well as the HB‐accepting capacity of fluorine itself, is still not completely understood. Although the formation of OH⋅⋅⋅F intramolecular HBs (IMHBs) has been established for conformationally restricted fluorohydrins, such interaction in flexible compounds remained questionable. Herein is demonstrated for the first time—and in contrast to earlier reports—the occurrence of OH⋅⋅⋅F IMHBs in acyclic saturated γ‐fluorohydrins, even for the parent 3‐fluoropropan‐1‐ol. The relative stereochemistry is shown to have a crucial influence on the corresponding h1JOH⋅⋅⋅F values, as illustrated by syn‐ and anti‐4‐fluoropentan‐2‐ol (6.6 and 1.9 Hz). The magnitude of OH⋅⋅⋅F IMHBs and their strong dependence on the overall molecular conformational profile, fluorination motif, and alkyl substitution level, is rationalized by quantum chemical calculations. For a given alkyl chain, the “rule of shielding” applies to OH⋅⋅⋅F IMHB energies. Surprisingly, the predicted OH⋅⋅⋅F IMHB energies are only moderately weaker than these of the corresponding OH⋅⋅⋅OMe. These results provide new insights of the impact of fluorination of aliphatic alcohols, with attractive perspectives for rational drug design.
The Renaissance of an Old Problem: Highly Regioselective Carboxylation of 2‐Alkynyl Bromides with Carbon Dioxide
Authors: Miao Bukeyan , Li Gen , Ma Shengming 
Published: October 2015

AbstractA steric effect‐controlled, zinc‐mediated carboxylation of different 2‐alkynyl bromides under an atmospheric pressure of CO2 has been developed by careful tuning of different reaction parameters, including the metal, solvent, temperature, and additive. 2‐Substituted 2,3‐allenoic acids were afforded from primary 2‐alkynyl bromides, whereas the carboxylation of secondary 2‐alkynyl bromides yielded 3‐alkynoic acids in decent yields. A rationale for the observed regioselectivity has been proposed.
Unique Separation Behavior of a C60 Fullerene‐Bonded Silica Monolith Prepared by an Effective Thermal Coupling Agent
Authors: Kubo Takuya , Murakami Yoshiki , Tsuzuki Madoka , Kobayashi Hiroshi , Naito Toyohiro , Sano Tomoharu , Yan Mingdi , Otsuka Koji 
Published: October 2015

AbstractHerein, we report a newly developed C60 fullerene‐bonded silica monolith in a capillary with unique retention behavior due to the structure of C60 fullerene. N‐Hydroxysuccinimide (NHS)‐conjugated C60 fullerene was successfully synthesized by a thermal coupling agent, perfluorophenyl azide (PFPA), and assigned by spectroscopic analyses. Then, NHS‐PFPA‐C60 fullerene was attached onto the surface of a silica monolith in a capillary. The capillary provided specific separation ability for polycyclic aromatic hydrocarbons in liquid chromatography by an effective π–π interaction. Furthermore, corannulene, which has a hemispherical structure, was selectively retained in the capillary based on the specific structural recognition due to the spherical C60 fullerene. This is the first report revealing the spherical recognition ability by C60 fullerene in liquid chromatographic separation.
Synthesis and Evaluation of Hybrid Structures Composed of Two Glucosylceramide Synthase Inhibitors
Authors: van den Berg Richard J. B. H. N. , van Rijssel Erwin R. , Ferraz Maria Joao , Houben Judith , Strijland Anneke , Donker‐Koopman Wilma E. , Wennekes Tom , Bonger Kimberly M. , Ghisaidoobe Amar B. T. , Hoogendoorn Sascha , van der Marel Gijsbert A. , Codée Jeroen D. C. , Overkleeft Herman S. , Aerts Johannes M. F. G. 
Published: October 2015

AbstractGlucosylceramide metabolism and the enzymes involved have attracted significant interest in medicinal chemistry, because aberrations in the levels of glycolipids that are derived from glucosylceramide are causative in a range of human diseases including lysosomal storage disorders, type 2 diabetes, and neurodegenerative diseases. Selective modulation of one of the glycoprocessing enzymes involved in glucosylceramide metabolism—glucosylceramide synthase (GCS), acid glucosylceramidase (GBA1), or neutral glucosylceramidase (GBA2)—is therefore an attractive research objective. In this study we took two established GCS inhibitors, one based on deoxynojirimycin and the other a ceramide analogue, and merged characteristic features to obtain hybrid compounds. The resulting 39‐compound library does not contain new GCS inhibitors; however, a potent (200 nm) GBA1 inhibitor was identified that has little activity toward GBA2 and might therefore serve as a lead for further biomedical development as a selective GBA1 modulator.
Vector data flow analysis for SIMD optimizations on OpenCL programs
Authors: Lin Yu‐Te , Lee Jenq‐Kuen 
Published: October 2015

SummaryMulti‐core systems equipped with micro processing units and accelerators such as digital signal processors (DSPs) and graphics processing units (GPUs) have become a major trend in processor design in recent years in attempts to meet ever‐increasing application performance requirements. Open Computing Language (OpenCL) is one of the programming languages that include new extensions proposed to exploit the computing power of these kinds of processors. Among the newly extended language features, the single‐instruction multiple‐data (SIMD) linguistics and vector types are added to OpenCL to exploit hardware features of the accelerators. The addition makes it necessary to consider how traditional compiler data flow analysis can be adopted to meet the optimization requirements of vector linguistics. In this paper, we propose a calculus framework to support the data flow analysis of vector constructs for OpenCL programs that compilers can use to perform SIMD optimizations. We model OpenCL vector operations as data access functions in the style of mathematical functions. We then show that the data flow analysis for OpenCL vector linguistics can be performed based on the data access functions. Based on the information gathered from data flow analysis, we illustrate a set of SIMD optimizations on OpenCL programs. The experimental results incorporating our calculus and our proposed compiler optimizations show that the proposed SIMD optimizations can provide average performance improvements of 22% on x86 CPUs and 4% on advanced micro devices GPUs. For the selected 15 benchmarks, 11 of them are improved on x86 CPUs, and six of them are improved on advanced micro devices GPUs. The proposed framework has the potential to be used to construct other SIMD optimizations on OpenCL programs. Copyright © 2015 John Wiley & Sons, Ltd.
Non‐Oxidative Dehydrogenation Pathways for the Conversion of C2–C4 Alcohols to Carbonyl Compounds
Authors: Shylesh Sankaranarayanapillai , Kim Daeyoup , Ho Christopher R. , Johnson Gregory R. , Wu Jason , Bell Alexis T. 
Published: October 2015

AbstractGold nanoparticles (NPs) supported on hydrotalcite (Au/HT) are highly active and selective catalysts for the continuous, gas‐phase, non‐oxidative dehydrogenation of bioderived C2–C4 alcohols. A sharp increase in turn over frequency (TOF) is noted when the size of Au NPs is less than 5 nm relating to the strong synergy between metallic Au NPs and the acid–base groups on the support surface. It is shown that catalytic activity depends critically on Au NP size, support composition, and support pretreatments. A reaction pathway elucidated from kinetic isotope effects suggests that the abstraction of β‐H by Au NPs (C−H activation) is the rate‐determining step in the dehydrogenation of bioderived C2–C4 alcohols.
Swimming through sand: connectivity of aquatic fauna in deserts
Authors: Murphy Ashley L. , Pavlova Alexandra , Thompson Ross , Davis Jenny , Sunnucks Paul 
Published: October 2015

AbstractFreshwater ecosystems in arid regions range from highly fragmented to highly connected, and connectivity has been assumed to be a major factor in the persistence of aquatic biota in arid environments. This review sought to synthesize existing research on genetic estimation of population connectivity in desert freshwaters, identify knowledge gaps, and set priorities for future studies of connectivity in these environments. From an extensive literature search, we synthesized the approaches applied, systems studied, and conclusions about connectivity reached in population genetic research concerning desert freshwater connectivity globally. We restrict our scope to obligate aquatic fauna that disperse largely via freshwaters and exclude those with active aerial dispersal abilities. We examined 92 papers, comprising 133 studies, published from 1987 to 2014. Most described studies of fishes and invertebrates in the deserts of Australia and North America. Connectivity declined with increasing scale, but did not differ significantly among arid regions or taxonomic classes. There were significant differences in connectivity patterns between species with different dispersal abilities, and between spring and riverine habitats at local scales. Population connectivity in desert freshwaters is typically most influenced by the ecology of the species concerned and hydrological connectivity. Most studies did not assess predefined models of connectivity, but described gene flow and/or genetic structure. Climate change and anthropogenic impacts worldwide are likely to increase the incidence and impact of habitat fragmentation in already threatened desert freshwaters. To reduce this risk, biodiversity conservation and environmental management must address connectivity, but often the required information does not exist. Researchers can provide this by explicitly considering the effects of hydrology and species’ ecology on connectivity, and incorporating these into connectivity models, which are vital for understanding connectivity in desert freshwaters.
Insertion of a [FeII(pyimH)3]2+ [pyimH = 2‐(1H‐Imidazol‐2‐yl)pyridine] Spin‐Crossover Complex Inside a Ferromagnetic Lattice Based on a Chiral 3D Bimetallic Ox­alate Network
Authors: López‐Jordà Maurici , Giménez‐Marqués Mónica , Desplanches Cédric , Mínguez Espallargas Guillermo , Clemente‐León Miguel , Coronado Eugenio 
Published: October 2015

AbstractThe insertion of the [FeII(pyimH)3]2+ [pyimH = 2‐(1H‐imidazol‐2‐yl)pyridine] spin‐crossover complex into a ferromagnetic bimetallic oxalate network affords the hybrid compound [FeII(pyimH)3][MnIICrIII(ox)3]2·X (ox = C2O42–). This spin‐crossover complex templates the growth of crystals formed by a chiral 3D oxalate network. The magnetic properties of this hybrid magnet show the coexistence of long‐range ferromagnetic ordering at 4.5 K and a spin crossover of the intercalated [FeII(pyimH)3]2+ complex above 250 K. The compound presents a light‐induced excited spin‐state trapping (LIESST) effect below 60 K although with limited photoconversion (less than 8 %).