bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rock magnetism of tiny exsolved magnetite in plagioclase from a Paleoarchean granitoid in the Pilbara craton
Authors: Usui Yoichi , Shibuya Takazo , Sawaki Yusuke , Komiya Tsuyoshi 
Published: November 2014

AbstractGranitoids are widespread in Precambrian terranes as well as the Phanerozoic orogenic belts, but they have garnered little attention in paleomagnetic studies, because granitoids often contain abundant coarse‐grained, magnetically unstable oxides. In this study, the first example of tiny, needle‐shaped, exsolved oxides in plagioclase in a Paleoarchean granitoid is reported. The magnetic properties of single plagioclase crystals with the exsolved oxide inclusions have been studied to determine their paleomagnetic recording fidelity. Demagnetization experiments and hysteresis parameters indicate that the oxide inclusions are near stoichiometric magnetite and magnetically very stable. First‐order reversal curve (FORC) diagrams reveal negligible magnetostatic interactions. Minimal interactions are also reflected by very efficient acquisition of anhysteretic remanent magnetization. Single plagioclase crystals exhibit strong magnetic remanence anisotropies, which require corrections to their paleodirectional and paleointensity data. Nonetheless, quantitative consideration of anisotropy tensors of the single plagioclase crystals indicates that the bias can be mitigated by properly averaging data from a few tens of single crystals. From the nonlinear thermoremanence acquisition of the plagioclase crystals, we estimate that the plagioclase crystals can reconstruct paleointensity up to 50 μT. Local metamorphic condition suggests that those magnetite may carry remanence of ∼3.2 to 3.3 Ga. We suggest that exsolved magnetite in granitoids is potentially a suitable target for the study of the early history of the geomagnetic field, and prompt detailed microscopic investigations as well as paleomagnetic tests to constrain the age of remanence.
Analytical steady‐state solutions for water‐limited cropping systems using saline irrigation water
Authors: Skaggs T. H. , Anderson R. G. , Corwin D. L. , Suarez D. L. 
Published: November 2014

AbstractDue to the diminishing availability of good quality water for irrigation, it is increasingly important that irrigation and salinity management tools be able to target submaximal crop yields and support the use of marginal quality waters. In this work, we present a steady‐state irrigated systems modeling framework that accounts for reduced plant water uptake due to root zone salinity. Two explicit, closed‐form analytical solutions for the root zone solute concentration profile are obtained, corresponding to two alternative functional forms of the uptake reduction function. The solutions express a general relationship between irrigation water salinity, irrigation rate, crop salt tolerance, crop transpiration, and (using standard approximations) crop yield. Example applications are illustrated, including the calculation of irrigation requirements for obtaining targeted submaximal yields, and the generation of crop‐water production functions for varying irrigation waters, irrigation rates, and crops. Model predictions are shown to be mostly consistent with existing models and available experimental data. Yet the new solutions possess advantages over available alternatives, including: (i) the solutions were derived from a complete physical‐mathematical description of the system, rather than based on an ad hoc formulation; (ii) the analytical solutions are explicit and can be evaluated without iterative techniques; (iii) the solutions permit consideration of two common functional forms of salinity induced reductions in crop water uptake, rather than being tied to one particular representation; and (iv) the utilized modeling framework is compatible with leading transient‐state numerical models.
Direct ortho‐Acylation of Azoxybenzenes with Aldehydes via Palladium‐Catalyzed Regioselective CH Bond Activation
Authors: Yi Meiling , Cui Xiuling , Zhu Chongwei , Pi Chao , Zhu Weimin , Wu Yangjie 
Published: November 2014

AbstractA highly efficient and convenient palladium catalyzed the ortho‐acylation of azoxybenzenes has been developed. Easily available aldehydes were used as a cheap and ideal aroyl sources. This method provides a practical and direct pathway to synthesize 2‐acylated azoxybenzenes in chemo‐ and regioselective manners via palladium‐catalyzed CH bond activation. Various substituents on both coupling partners are tolerated well.
Synthesis, Dynamic Combinatorial Chemistry, and PCR Amplification of 3′–5′ and 3′–6′ Disulfide‐linked Oligonucleotides
Authors: Hansen Dennis Jul , Manuguerra Ilenia , Kjelstrup Michael Brøndum , Gothelf Kurt Vesterager 
Published: November 2014

AbstractDisulfide dithymidines linked 3′–5′ or 3′–6′ were synthesized and incorporated into oligonucleotides through a combined phosphotriester and phosphoramidite solid‐phase oligonucleotide synthesis approach. The disulfide links are cleaved and formed reversibly in the presence of thiols and oligonucleotides. This link was shown to be sequence‐adaptive in response to given templates in the presence of mercaptoethanol. The artificial 3′–5′ and 3′–6′ disulfide link was tolerated by polymerases in the polymerase chain reaction (PCR). By using sequencing analysis, we show that single mutations frequently occurred randomly in the amplification products of the PCR.
Molekulare Seltenerdmetallhydride in Nicht‐Cyclopentadienyl‐Umgebungen
Authors: Fegler Waldemar , Venugopal Ajay , Kramer Mathias , Okuda Jun 
Published: November 2014

AbstractMolekulare Hydride der Seltenerdmetalle spielen eine wichtige Rolle als homogene Katalysatoren und als Modelle für Einlagerungshydride im Festkörper. Mit strukturell gut charakterisierten Hydridkomplexen vom Nichtmetallocen‐Typ lassen sich Elementarreaktionen studieren, die an Seltenerdmetallzentren ablaufen. Untersuchen lassen sich auch katalytische Reaktionen, bei denen Seltenerdmetall‐Hydrid‐Bindungen beteiligt sind. Über neutrale Hydride hinaus sind nun auch kationische Derivate zugänglich.
Redoxkontrolle eines dendritischen Ferrocenyl‐basierten Homogenkatalysators
Authors: Neumann Paul , Dib Hanna , Caminade Anne‐Marie , Hey‐Hawkins Evamarie 
Published: November 2014

AbstractEs wird über die erste Anwendung eines dendritischen Katalysators in einem redoxschaltbaren katalytischen Prozess berichtet. Dafür wurden unter Ausnutzung der Redoxeigenschaften des Ferrocens ein monomerer sowie der entsprechende dendritische Ferrocenylphosphanligand entwickelt. Die katalytische Aktivität der Ruthenium(II)‐Komplexe konnte durch chemische Oxidation bzw. Reduktion der Ferroceneinheit reversibel geschaltet werden. Die oxidierte Ferroceniumeinheit entzieht dem Phosphan über das konjugierte π‐System Elektronendichte und senkt somit dessen Basizität. Das dadurch entstehende elektronenarme Rutheniumatom zeigt eine deutlich abgeschwächte Aktivität, die Reaktionsgeschwindigkeit wird drastisch gesenkt.
Metallfreie Carbonylierung durch Photoredoxkatalyse
Authors: Majek Michal , Jacobi von Wangelin Axel 
Published: November 2014

AbstractSynthesen von Benzoesäureestern aus Kohlenmonoxid und Arylelektrophilen zählen zu den bedeutendsten übergangsmetallkatalysierten Carbonylierungen und finden vielfältige Anwendung in Forschung und Produktion. Diese Reaktionen laufen unter Pd‐ oder Ni‐Katalyse in Gegenwart geeigneter Liganden und stöchiometrischer Mengen Base ab. Wir haben ein alternatives metall‐, ligand‐ und basenfreies Protokoll entwickelt. Die Methode erlaubt die Synthese von Alkylbenzoesäureestern aus Aryldiazoniumsalzen, CO und Alkoholen unter milden Bedingungen durch eine mit sichtbarem Licht getriebene, Eosin‐Y‐katalysierte Redoxreaktion. Selbst tertiäre Alkylester können in hohen Ausbeuten erhalten werden. DFT‐Rechnungen und Radikalfangexperimente belegen den Photoredox‐Mechanismus ohne zusätzliche Redoxpartner.
Großflächige Anordnung von Wolframoxidnanodrähten auf ebenen und strukturierten Substraten für Gassensorik bei Raumtemperatur
Authors: Cheng Wei , Ju Yanrui , Payamyar Payam , Primc Darinka , Rao Jingyi , Willa Christoph , Koziej Dorota , Niederberger Markus 
Published: November 2014

AbstractGroßflächiges Anordnen von Nanodrähten auf ebenen und strukturierten Substraten bildet die Voraussetzung für die Nutzung kollektiver Eigenschaften z. B. in der Gassensorik. In der hier vorgestellten Arbeit wurden gleichförmige, einkristalline und ultradünne W18O49‐Nanodrähte mit einem Durchmesser <2 nm und einem Aspektverhältnis >100 synthetisiert. Trotz ihrer großen mechanischen Flexibilität konnten sie mithilfe der Langmuir‐Blodgett‐Technik zu Dünnschichten mit hoher Ordnung auf einem makroskopischen Flächenbereich angeordnet werden. Das Anordnen der Wolframoxidnanodrähte konnte auch auf Sensorsubstraten mit Elektroden durchgeführt werden. Diese Sensoren zeigten bei Raumtemperatur hervorragende Eigenschaften für die H2‐Messung.
Co‐development of Crystalline and Mesoscopic Order in Mesostructured Zeolite Nanosheets
Authors: Messinger Robert J. , Na Kyungsu , Seo Yongbeom , Ryoo Ryong , Chmelka Bradley F. 
Published: November 2014

AbstractMesoporous zeolites are a new and technologically important class of materials that exhibit improved diffusion and catalytic reaction properties compared to conventional zeolites with sub‐nanometer pore dimensions. During their syntheses, the transient developments of crystalline and mesoscopic order are closely coupled and challenging to control. Correlated solid‐state NMR, X‐ray, and electron microscopy analyses yield new molecular‐level insights on the interactions and distributions of complicated organic structure‐directing agents with respect to crystallizing zeolite frameworks. The analyses reveal the formation of an intermediate layered silicate phase, which subsequently transforms into zeolite nanosheets with uniform nano‐ and mesoscale porosities. Such materials result from coupled surfactant self‐assembly and inorganic crystallization processes, the interplay between which governs the onset and development of framework structural order on different length and time scales.
A Two‐in‐one Pincer Ligand and its Diiron(II) Complex Showing Spin State Switching in Solution through Reversible Ligand Exchange
Authors: Samanta Subhas , Demesko Serhiy , Dechert Sebastian , Meyer Franc 
Published: November 2014

AbstractA novel pyrazolate‐bridged ligand providing two {PNN} pincer‐type compartments has been synthesized. Its diiron(II) complex LFe2(OTf)3(CH3CN) (1; Tf=triflate) features, in solid state, two bridging triflate ligands, with a terminal triflate and a MeCN ligand completing the octahedral coordination spheres of the two high‐spin metal ions. In MeCN solution, 1 is shown to undergo a sequential, reversible, and complete spin transition to the low‐spin state upon cooling. Detailed UV/Vis and 19F NMR spectroscopic studies as well as magnetic measurements have unraveled that spin state switching correlates with a rapid multistep triflate/MeCN ligand exchange equilibrium. The spin transition temperature can be continuously tuned by varying the triflate concentration in solution.
Activatable 19F MRI Nanoparticle Probes for the Detection of Reducing Environments
Authors: Nakamura Tatsuya , Matsushita Hisashi , Sugihara Fuminori , Yoshioka Yoshichika , Mizukami Shin , Kikuchi Kazuya 
Published: November 2014

Abstract19F magnetic resonance imaging (MRI) probes that can detect biological phenomena such as cell dynamics, ion concentrations, and enzymatic activity have attracted significant attention. Although perfluorocarbon (PFC) encapsulated nanoparticles are of interest in molecular imaging owing to their high sensitivity, activatable PFC nanoparticles have not been developed. In this study, we showed for the first time that the paramagnetic relaxation enhancement (PRE) effect can efficiently decrease the 19F NMR/MRI signals of PFCs in silica nanoparticles. On the basis of the PRE effect, we developed a reduction‐responsive PFC‐encapsulated nanoparticle probe, FLAME‐SS‐Gd3+ (FSG). This is the first example of an activatable PFC‐encapsulated nanoparticle that can be used for in vivo imaging. Calculations revealed that the ratio of fluorine atoms to Gd3+ complexes per nanoparticle was more than approximately 5.0×102, resulting in the high signal augmentation.
Thiophene‐Based, Radial π‐Conjugation: Synthesis, Structure, and Photophysical Properties of Cyclo‐1,4‐phenylene‐2′,5′‐thienylenes
Authors: Ito Hideto , Mitamura Yukari , Segawa Yasutomo , Itami Kenichiro 
Published: November 2014

AbstractThe synthesis of cyclo‐1,4‐phenylene‐2′,5′‐thienylenes (CPTs) as the first example of a thiophene‐based, radially π‐conjugated system is described. X‐ray crystal structures, UV‐vis absorption and emission spectra, and theoretical studies revealed the unique structural and photophysical properties of CPTs. With all of these unique structural and photophysical properties, the radially π‐conjugated CPTs are expected to open a door for the discovery and development of new functional organic materials.
Self‐Alignment of Low‐Valent Octanuclear Palladium Atoms
Authors: Nakamae Kanako , Takemura Yukie , Kure Bunsho , Nakajima Takayuki , Kitagawa Yasutaka , Tanase Tomoaki 
Published: November 2014

AbstractA linear tetraphosphine, meso‐bis[(diphenylphosphinomethyl)phenylphosphino]methane (dpmppm) was used to synthesize linear octapalladium‐extended metal atom chains as discrete molecules of [Pd8(μ‐dpmppm)4](BF4)4 (1) and [Pd8(μ‐dpmppm)4L2](BF4)4 (L=2,6‐xylyl isocyanide (XylNC; 2), acetonitrile (3), and N,N‐dimethylformamide (dmf; 4)), which are stable in the solution states and show interesting temperature‐dependent photochemical properties in the near IR region. Variable temperature NMR studies demonstrated that at higher temperature T≈140 °C the Pd8 chains were dissociated into Pd4 fragments, which were thermodynamically self‐aligned to restore the Pd8 chains at lower temperature T<60 °C. The coldspray ionization mass spectra suggested a possibility for further aggregation of the linear tetrapalladium units.
Redox Properties of CeO2 at Low Temperature: The Direct Synthesis of Imines from Alcohol and Amine
Authors: Tamura Masazumi , Tomishige Keiichi 
Published: November 2014

AbstractWe disclosed the redox properties of CeO2 in organic reactions at low temperature of 303 K. CeO2 works as the most effective heterogeneous catalyst for imine formation from benzyl alcohol and aniline at 303 K among various metal oxides and showed more than 38‐fold higher activity than other simple metal oxides. CeO2 is applicable to the reaction of various alcohols and amines and gives high yields (80–98 %) and high selectivities (89–>99 %). Kinetic measurements, MS, and FTIR analyses demonstrated that the high activity of CeO2 is a result of reactive oxygen species at the redox sites on CeO2. This discovery can help to create a new field in metal oxide catalysis.
Asymmetric Dearomatization of β‐Naphthols through an Amination Reaction Catalyzed by a Chiral Phosphoric Acid
Authors: Wang Shou‐Guo , Yin Qin , Zhuo Chun‐Xiang , You Shu‐Li 
Published: November 2014

AbstractA highly efficient catalytic asymmetric dearomatization of naphthols by means of an electrophilic amination reaction catalyzed by chiral phosphoric acid is presented. This protocol provides a facile access to functionalized β‐naphthalenone compounds with a chiral quaternary carbon center in excellent yields and enantioselectivity (up to 99 % yield, up to 96 % ee).
Photocatalytic Reduction of Carbon Dioxide by Hydrous Hydrazine over Au–Cu Alloy Nanoparticles Supported on SrTiO3/TiO2 Coaxial Nanotube Arrays
Authors: Kang Qing , Wang Tao , Li Peng , Liu Lequan , Chang Kun , Li Mu , Ye Jinhua 
Published: November 2014

AbstractEfficient photocatalytic conversion of CO2 into CO and hydrocarbons by hydrous hydrazine (N2H4⋅H2O) is achieved on SrTiO3/TiO2 coaxial nanotube arrays loaded with Au–Cu bimetallic alloy nanoparticles. The synergetic catalytic effect by the Au–Cu alloy nanoparticles and the fast electron‐transfer in SrTiO3/TiO2 coaxial nanoarchitecture are the main reasons for the efficiency, while N2H4⋅H2O as the H source and electron donor provides a reducing atmosphere to protect the surface Cu atoms from oxidation, therefore maintaining the alloying effect which is the basis for the high photocatalytic activity and stability. This approach opens a feasible route to enhance the photocatalytic efficiency, which also benefits the development of photocatalysts and co‐catalysts.
ASEAN's Leadership in the Regional Comprehensive Economic Partnership
Authors: Fukunaga Yoshifumi 
Published: November 2014

AbstractAssociation of Southeast Asian Nations (ASEAN) centrality was one of the biggest motivations for ASEAN's proposal of the Regional Comprehensive Economic Partnership (RCEP) in 2011. In order to gain both politically and economically, ASEAN should play proactive roles in the RCEP negotiation as the driver of substance. ASEAN has already started exercising its influence over the substances of ASEAN + 1 free trade agreements (FTAs). In order to further strengthen its leadership in the RCEP, ASEAN should utilise the ASEAN Economic Community (AEC) as the model for RCEP. AEC has achieved a much deeper level of integration than the existing ASEAN + 1 FTAs by setting high ambitions with processes to induce reform initiatives of member states. By using familiar AEC measures, ASEAN can create a single and common position despite the large development gaps among its member states. If modelled after AEC, the RCEP will enforce ASEAN's reform efforts.
Development and validation of a sensitive UHPLC‐MS/MS method for the simultaneous analysis of tramadol, dextromethorphan chlorpheniramine and their major metabolites in human plasma in forensic context: application to pharmacokinetics
Authors: Heneedak Hala M. , Salama Ismail , Mostafa Samia , EL‐Kady Ehab , El‐Sadek Mohamed 
Published: November 2014

AbstractThe prerequisites for forensic confirmatory analysis by LC/MS/MS with respect to European Union guidelines are chromatographic separation, a minimum number of two MS/MS transitions to obtain the required identification points and predefined thresholds for the variability of the relative intensities of the MS/MS transitions (MRM transitions) in samples and reference standards. In the present study, a fast, sensitive and robust method to quantify tramadol, chlorpheniramine, dextromethorphan and their major metabolites, O‐desmethyltramadol, dsmethyl‐chlorpheniramine and dextrophan, respectively, in human plasma using ibuprofen as internal standard (IS) is described. The analytes and the IS were extracted from plasma by a liquid–liquid extraction method using ethyl acetate–diethyl‐ether (1:1). Extracted samples were analyzed by ultra‐high‐performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC‐ESI‐MS/MS). Chromatographic separation was performed by pumping the mobile phase containing acetonitrile, water and formic acid (89.2:11.7:0.1) for 2.0 min at a flow rate of 0.25 μL/min into a Hypersil‐Gold C18 column, 20 × 2.0 mm (1.9 µm) from Thermoscientific, New York, USA. The calibration curve was linear for the six analytes. The intraday precision (RSD) and accuracy (RE) of the method were 3–9.8 and −1.7–4.5%, respectively. The analytical procedure herein described was used to assess the pharmacokinetics of the analytes in 24 healthy volunteers after a single oral dose containing 50 mg of tramadol hydrochloride, 3 mg chlorpheniramine maleate and 15 mg of dextromethorphan hydrobromide. Copyright © 2014 John Wiley & Sons, Ltd.
Vortex particle smoke simulation with an octree data structure
Authors: Huang Zhanpeng , Gong Guanghong , Han Liang 
Published: November 2014

AbstractWe propose an octree‐based presentation of vortex particles to simulate smoke and gaseous phenomena in a physical way. Vortex particle method prevails over grid‐based method in terms of less numerical dissipation and more detail features, but it suffers from heavy computational overhead due to per‐particle Biot–Savart integration over the entire simulation space. To alleviate this problem, we employ an octree background grid to separate the vortex particles into individual groups. Particles in groups are aggregated as a single super vortex particle to reduce computational cost. The proposed method produces comparable visual result as previous methods with much less computational overhead. Copyright © 2014 John Wiley & Sons, Ltd.
Asymmetric Organocatalyzed Epoxidation of 2‐Oxoindoline‐3‐ylidene Acetaldehydes
Authors: Mukaiyama Takasuke , Ogata Kento , Ono Tsuyoshi , Hayashi Yujiro 
Published: November 2014

AbstractThe asymmetric epoxidation of 2‐oxoindoline‐3‐ylidene acetaldehydes, catalyzed by diarylprolinol silyl ether, has been developed. The reaction provides oxindole derivatives possessing chiral epoxides in good yield with good diastereoselectivity and excellent enantioselectivity.
Asymmetric Tandem 1,5‐Hydride Shift/Ring Closure for the Synthesis of Chiral Spirooxindole Tetrahydroquinolines
Authors: Cao Weidi , Liu Xiaohua , Guo Jing , Lin Lili , Feng Xiaoming 
Published: November 2014

AbstractThe direct functionalization of sp3 CH bonds through a tandem 1,5‐hydride shift/ring closure is described. Various optically active spirooxindole tetrahydroquinoline derivatives bearing contiguous quaternary or tertiary stereogenic carbon centers were readily synthesized. A chiral scandium complex of N,N′‐dioxide promoted the reactions in good yields (up to 97 %) with excellent diastereoselectivities (>20:1) and enantioselectivities (up to 94 % ee). Kinetic isotope effect (KIE) experiments and internal redox reactions of chiral substrates were conducted, and the results provided intriguing information that helped clarify the mechanism of the reaction.
Phenylene Ethynylene‐Tethered Perylene Bisimide Folda‐Dimer and Folda‐Trimer: Investigations on Folding Features in Ground and Excited States
Authors: Fimmel Benjamin , Son Minjung , Sung Young Mo , Grüne Matthias , Engels Bernd , Kim Dongho , Würthner Frank 
Published: November 2014

AbstractIn this work, we have elucidated in detail the folding properties of two perylene bisimide (PBI) foldamers composed of two and three PBI units, respectively, attached to a phenylene ethynylene backbone. The folding behaviors of these new PBI folda‐dimer and trimer have been studied by solvent‐dependent UV/Vis absorption and 1D and 2D NMR spectroscopy, revealing facile folding of both systems in tetrahydrofuran (THF). In CHCl3 the dimer exists in extended (unfolded) conformation, whereas partially folded conformations are observed in the trimer. Temperature‐dependent 1H NMR spectroscopic studies in [D8]THF revealed intramolecular dynamic processes for both PBI foldamers due to, on the one hand, hindered rotation around CN imide bonds and, on the other hand, backbone flapping; the latter process being energetically more demanding as it was observed only at elevated temperature. The structural features of folded conformations of the dimer and trimer have been elucidated by different 2D‐NMR spectroscopy (e.g., ROESY and DOSY) in [D8]THF. The energetics of folding processes for the PBI dimer and trimer have been assessed by calculations applying various methods, particularly the semiempirical PM6‐DH2 and the more sophisticated B97D approach, in which relevant dispersion corrections are included. These calculations corroborate the results of NMR spectroscopic studies. Folding features in the excited states of these PBI foldamers have been characterized by using time‐resolved fluorescence and transient absorption spectroscopy in THF and CHCl3, exhibiting similar solvent‐dependent behavior as observed for the ground state. Interestingly, photoinduced electron transfer (PET) process from electron‐donating backbone to electron‐deficient PBI core for extended, but not for folded, conformations was observed, which can be explained by a fast relaxation of excited PBI stacks in the folded conformation into fluorescent excimer states.