bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pregnancy complicated by focal nodular hyperplasia: a case report of one woman over two consecutive courses of pregnancy
Authors: Gomi Yousuke , Takagi Kenjiro , Matunaga Shigetaka , Matsumura Hideyoshi , Saito Masahiro , Seki Hiroyuki 
Published: October 2013

Key Clinical MessageWe encountered a woman with a preexisting large focal nodular hyperplasia (FNH) of the liver, persisting during two separate pregnancies. FNH size was not affected by either pregnancy. Her elevated serum γ‐glutamyltransferase and alkaline phosphatase levels before pregnancy were reduced during both pregnancies, but returned to prepregnancy levels after delivery.
Mesoporous Silica‐Confined Manganese Oxide Nanoparticles as Highly Efficient Catalysts for the Low‐Temperature Elimination of Formaldehyde
Authors: Averlant Rémy , Royer Sébastien , Giraudon Jean‐Marc , Bellat Jean‐Pierre , Bezverkhyy Igor , Weber Guy , Lamonier Jean‐François 
Published: October 2013

AbstractManganese(IV) oxide was synthesized through crystallization in confined space by using the SBA‐15 silica support. The evolution of textural, morphological, structural, and redox properties of the manganese phase in the composites has been studied in terms of different parameters such as impregnation route, manganese loading, and activation temperature. High performances of nanoscaled manganese(IV) oxide for low‐temperature formaldehyde oxidation have been obtained. The optimization of preparation parameters enabled the complete conversion of formaldehyde at temperatures as low as 130 °C, which is comparable to the activity of the reference platinum catalyst that demonstrates complete conversion at similar temperatures.
Core–Shell Nanocatalyst Design by Combining High‐Throughput Experiments and First‐Principles Simulations
Authors: Rao Peela Nageswara , Zheng Weiqing , Lee Ivan C. , Karim Ayman M. , Vlachos Dionisios G. 
Published: October 2013

AbstractDespite significant research efforts, designing bimetallic catalysts rationally remains a challenging task. Herein, we combine the strengths of high‐throughput experiments and DFT calculations synergistically to design new core–shell bimetallic catalysts. The total oxidation of propane is used as a probe, proof‐of‐concept reaction. The methodology is successful in designing three bimetallic catalysts. Of these catalysts, AgPd is cheaper, more active than the existing most active single‐metal catalyst (Pt), and stable under the reaction conditions. Extended X‐ray absorption fine structure characterization confirms the formation of a bimetallic alloy. This study provides a path forward for designing bimetallic catalysts rationally for vapor phase metal‐catalyzed reactions.
Stable Performance of Ni Catalysts in the Dry Reforming of Methane at High Temperatures for the Efficient Conversion of CO2 into Syngas
Authors: Mette Katharina , Kühl Stefanie , Düdder Hendrik , Kähler Kevin , Tarasov Andrey , Muhler Martin , Behrens Malte 
Published: October 2013

AbstractThe catalytic performance of a Ni/MgAlOx catalyst was investigated in the high temperature CO2 reforming of CH4. The catalyst was developed using a Ni, Mg, Al hydrotalcite‐like precursor obtained by co‐precipitation. Despite the high Ni loading of 55 wt%, the synthesized Ni/MgAlOx catalyst possessed a thermally stable microstructure up to 900 °C with Ni nanoparticles of 9 nm. This stability is attributed to the embedding nature of the oxide matrix, and allows increasing the reaction temperature without losing active Ni surface area. To evaluate the effect of the reaction temperature on the reforming performance and the coking behavior, two different reaction temperatures (800 and 900 °C) were investigated. At both temperatures the prepared catalyst showed high rates of CH4 consumption. The higher temperature promotes the stability of the catalyst performance due to mitigation of the carbon formation.
CFD‐DEM Model for Simulating Solid Exchange in a Dual‐Leg Fluidized Bed
Authors: Yang C. , Duan Y. 
Published: October 2013

AbstractThe domain coverage method (DCM) is proposed to establish a computational fluid dynamics‐discrete element method (CFD‐DEM) model based on irregular mesh. The gas field was solved by Fluent software and the DEM model was coupled with Fluent software by user‐defined functions. Gas turbulent viscosity was calculated by the coupled k‐ϵ two‐equation model and the soft‐sphere collision model was used to get particle contact force. The CFD‐DEM model based on irregular mesh was firstly verified to be reasonable by comparing the simulated injected bubble with that simulated by Bokkers et al. The solid exchange behavior was studied numerically in a 2D dual‐leg fluidized bed (DL‐FB). The simulation results were compared with experimental results and proved that the CFD‐DEM model is established successfully based on the efficient DCM. The DEM model is expanded to be used on irregular mesh in fluidized beds with complex geometries.
Influence of Geometry Structures on the Transfer and Flow Characteristics of Membrane Modules
Authors: Wu X.‐K. , Sha H.‐F. , Zhang F. , Wu F.‐W. , Zhang Z.‐B. , Wang Z.‐X. 
Published: October 2013

AbstractThe effects of different inlet/outlet features and helical structures on the flow pattern and transfer performance of membrane modules were investigated with both three‐dimensional computational fluid dynamics and experimental methods. In a circular flat membrane module, two types of inlet/outlet with single‐port or three‐port configuration were used to evaluate the influence of small differences in the opening area structure of the inlet/outlet on the flow patterns. Although the transfer regions differ, large flow swirls appear in both systems, leading to stagnation regions and causing significant back‐mixing. To alleviate the swirls and improve the flow pattern, a helix clapboard was used to separate the membrane feed channel as spiral channel. Both the numerical and experimental results indicate that the helical structure can greatly enhance the transfer performance and increase the permeation rate while the increment in energy consumption is very small.
Synthesis of a Green Fuel Additive Over Cation Resins
Authors: Zheng Y. , Tang Q. , Wang T. , Liao Y. , Wang J. 
Published: October 2013

AbstractThe synthesis of polyoxymethylene dimethyl ethers (PODEn), being green diesel fuel additives, from dimethoxymethane (DMM) and paraformaldehyde over three different cation resins, namely NKC‐9, D001‐CC, and D72, in a stirred‐autoclave reactor was investigated. The pore size distribution and surface area were measured with nitrogen adsorption‐desorption. NKC‐9 had a larger exchange capacity, better developed porosity structure, and higher reaction activity than D001‐CC and D72. The effects of reaction temperature, DMM/CH2O molar ratio, reaction time, and catalyst loading were studied with NKC‐9. A possible mechanism was explored to describe the bond reorganizations during the reactions.
Liquid|Liquid Interfacial Photoelectrochemistry of Chromoionophore I Immobilised in 4‐(3‐Phenylpropyl)Pyridine Microdroplets
Authors: Bartlett Thomas R. , Ahmed Safeer , Tuna Floriana , Collison David , Blanchard Gary J. , Marken Frank 
Published: October 2013

AbstractPhotoelectrochemical processes are investigated for chromoionophore I (ETH 5294) dissolved in 4‐(3‐phenylpropyl)pyridine (PPP) and deposited in the form of a microdroplet array (through evaporation deposition from a solution in acetonitrile) onto a 5 mm diameter basal plane pyrolytic graphite (BPPG) electrode. Stable biphasic dark voltammetric responses (two electron/two proton) are observed in phosphate buffer solution (from pH 2 to 12) with a switch in reactivity at pH 5 due to a biphasic protonation step. The photoelectrochemical activity at pH 2 is investigated further by phototransient amperometry. The protonated chromoionophore I is shown to be the photoactive component (supported by EPR data) and “hole transfer” at the liquid|liquid interface to aqueous oxalate is demonstrated. This interfacial hole‐transfer process can be “switched off” by hydrophobic anions (PF6−), which compete for cationic liquid|liquid PPP surface binding sites. Implications for light harvesting and liquid semiconductor properties are discussed.
Novel Tripod Amphiphiles for Membrane Protein Analysis
Authors: Chae Pil Seok , Kruse Andrew C. , Gotfryd Kamil , Rana Rohini R. , Cho Kyung Ho , Rasmussen Søren G. F. , Bae Hyoung Eun , Chandra Richa , Gether Ulrik , Guan Lan , Kobilka Brian K. , Loland Claus J. , Byrne Bernadette , Gellman Samuel H. 
Published: October 2013

AbstractIntegral membrane proteins play central roles in controlling the flow of information and molecules across membranes. Our understanding of membrane protein structures and functions, however, is seriously limited, mainly due to difficulties in handling and analysing these proteins in aqueous solution. The use of a detergent or other amphipathic agents is required to overcome the intrinsic incompatibility between the large lipophilic surfaces displayed by the membrane proteins in their native forms and the polar solvent molecules. Here, we introduce new tripod amphiphiles displaying favourable behaviours toward several membrane protein systems, leading to an enhanced protein solubilisation and stabilisation compared to both conventional detergents and previously described tripod amphiphiles.
Crystalline Hybrid Solid Materials of Palladium and Decamethylcucurbit[5]uril as Recoverable Precatalysts for Heck Cross‐Coupling Reactions
Authors: Li Hongfang , Lü Jian , Lin Jingxiang , Huang Yuanbiao , Cao Minna , Cao Rong 
Published: October 2013

AbstractA series of MPdMe10CB[5] (M=Li, Na, K, Rb, and Cs; Me10CB[5]=decamethylcucurbit[5]uril) hybrid solid materials have been successfully synthesized for the first time through a simple diffusion method. These as‐prepared hybrid solids have been applied as phosphine‐free precatalysts for Heck cross‐coupling reactions with excellent catalytic performance and good recyclability. In the processes of the catalytic reactions, the activated PdII species were released from the crystalline hybrid precatalysts and transformed into catalytically active Pd nanoparticles, which have been demonstrated as key to carry on the catalytic reactions for the recoverable precatalysts MPdMe10CB[5] (M=K, Rb, and Cs). It has also been rationalized that the introduction of different alkali metals afforded crystalline hybrid precatalysts with different crystal structures, which are responsible for their diversified stability and reusability presented in Heck reactions.
Rapid Acquisition of 14N Solid‐State NMR Spectra with Broadband Cross Polarization
Authors: Harris Kristopher J. , Veinberg Stanislav L. , Mireault Christopher R. , Lupulescu Adonis , Frydman Lucio , Schurko Robert W. 
Published: October 2013

AbstractNitrogen is an element of utmost importance in chemistry, biology and materials science. Of its two NMR‐active isotopes, 14N and 15N, solid‐state NMR (SSNMR) experiments are rarely conducted upon the former, due to its low gyromagnetic ratio (γ) and broad powder patterns arising from first‐order quadrupolar interactions. In this work, we propose a methodology for the rapid acquisition of high quality 14N SSNMR spectra that is easy to implement, and can be used for a variety of nitrogen‐containing systems. We demonstrate that it is possible to dramatically enhance 14N NMR signals in spectra of stationary, polycrystalline samples (i.e., amino acids and active pharmaceutical ingredients) by means of broadband cross polarization (CP) from abundant nuclei (e.g., 1H). The BRoadband Adiabatic INversion Cross‐Polarization (BRAIN–CP) pulse sequence is combined with other elements for efficient acquisition of ultra‐wideline SSNMR spectra, including Wideband Uniform‐Rate Smooth‐Truncation (WURST) pulses for broadband refocusing, Carr–Purcell Meiboom–Gill (CPMG) echo trains for T2‐driven S/N enhancement, and frequency‐stepped acquisitions. The feasibility of utilizing the BRAIN–CP/WURST–CPMG sequence is tested for 14N, with special consideration given to (i) spin‐locking integer spin nuclei and maintaining adiabatic polarization transfer, and (ii) the effects of broadband polarization transfer on the overlapping satellite transition patterns. The BRAIN–CP experiments are shown to provide increases in signal‐to‐noise ranging from four to ten times and reductions of experimental times from one to two orders of magnitude compared to analogous experiments where 14N nuclei are directly excited. Furthermore, patterns acquired with this method are generally more uniform than those acquired with direct excitation methods. We also discuss the proposed method and its potential for probing a variety of chemically distinct nitrogen environments.
Nearly Degenerate Isomers of C(BH)2: Cumulene, Carbene, or Carbone?
Authors: Barua Shiblee R. , Allen Wesley D. , Kraka Elfi , Jerabek Paul , Sure Rebecca , Frenking Gernot 
Published: October 2013

AbstractThe ground electronic state of C(BH)2exhibits both a linear minimum and a peculiar angle‐deformation isomer with a central B‐C‐B angle near 90°. Definitive computations on these species and the intervening transition state have been executed by means of coupled‐cluster theory including single and double excitations (CCSD), perturbative triples (CCSD(T)), and full triples with perturbative quadruples (CCSDT(Q)), in concert with series of correlation‐consistent basis sets (cc‐pVXZ,X=D, T, Q, 5, 6; cc‐pCVXZ,X=T, Q). Final energies were pinpointed by focal‐point analyses (FPA) targeting the complete basis‐set limit of CCSDT(Q) theory with auxiliary core correlation, relativistic, and non‐Born–Oppenheimer corrections. Isomerization of the linear species to the bent form has a minuscule FPA reaction energy of 0.02 kcal mol−1and a corresponding barrier of only 1.89 kcal mol−1. Quantum tunneling computations reveal interconversion of the two isomers on a timescale much less than 1 s even at 0 K. Highly accurate CCSD(T)/cc‐pVTZ and composite c∼CCSDT(Q)/cc‐pCVQZ anharmonic vibrational frequencies confirm matrix‐isolation infrared bands previously assigned to linear C(BH)2and provide excellent predictions for the heretofore unobserved bent isomer. Chemical bonding in the C(BH)2species was exhaustively investigated by the atoms‐in‐molecules (AIM) approach, molecular orbital plots, various population analyses, local mode vibrations and force constants, unified reaction valley analysis (URVA), and other methods. Linear C(BH)2is a cumulene, whereas bent C(BH)2is best characterized as a carbene with little carbone character. Weak B–B attraction is clearly present in the unusual bent isomer, but its strength is insufficient to form a CB2ring with a genuine boron–boron bond and attendant AIM bond path.
Reaction‐Based and Single Fluorescent Emitter Decorated Ratiometric Nanoprobe to Detect Hydrogen Peroxide
Authors: Chen Chun‐Yen , Chen Chao‐Tsen 
Published: October 2013

AbstractA novel reaction‐based cross‐linked polymeric nanoprobe with a self‐calibrating ratiometric fluorescence readout to selectively detect H2O2 is reported. The polymeric nanoprobe is fabricated by using hydrophobic H2O2‐reactive boronic ester groups, crosslinker units, and environmentally sensitive 3‐hydroxyflavone fluorophores through a miniemulsion polymerization. On treatment with H2O2, the boronic esters in the polymer are cleaved to form hydrophilic alcohols and subsequently lead to a hydrophobic–hydrophilic transition. Covalently linked 3‐hydroxyflavones manifest the change in polarity as a ratiometric transition from green to blue, accompanied by a 500‐fold increase in volume. Furthermore, this nanoprobe has been used for ratiometric sensing of glucose by monitoring the H2O2 generated during the oxidation of glucose by glucose oxidase, and thus successfully distinguished between normal and pathological levels of glucose.
High‐Pressure Synthesis and Characterization of New Actinide Borates, AnB4O8 (An=Th, U)
Authors: Hinteregger Ernst , Hofer Thomas S. , Heymann Gunter , Perfler Lukas , Kraus Florian , Huppertz Hubert 
Published: October 2013

AbstractNew actinide borates ThB4O8 and UB4O8 were synthesized under high‐pressure, high‐temperature conditions (5.5 GPa/1100 °C for thorium borate, 10.5 GPa/1100 °C for the isotypic uranium borate) in a Walker‐type multianvil apparatus from their corresponding actinide oxide and boron oxide. The crystal structure was determined on basis of single‐crystal X‐ray diffraction data that were collected at room temperature. Both compounds crystallized in the monoclinic space group C2/c (Z=4). Lattice parameters for ThB4O8: a=1611.3(3), b=419.86(8), c=730.6(2) pm; β=114.70(3)°; V=449.0(2) Å3; R1=0.0255, wR2=0.0653 (all data). Lattice parameters for UB4O8: a=1589.7(3), b=422.14(8), c=723.4(2) pm; β=114.13(3)°; V=443.1(2) Å3; R1=0.0227, wR2=0.0372 (all data). The new AnB4O8 (An=Th, U) structure type is constructed from corner‐sharing BO4 tetrahedra, which form layers in the bc plane. One of the four independent oxygen atoms is threefold‐coordinated. The actinide cations are located between the boron–oxygen layers. In addition to Raman spectroscopic investigations, DFT calculations were performed to support the assignment of the vibrational bands.
Insight into Lewis Acid Catalysis with Alkaline‐Earth MOFs: The Role of Polyhedral Symmetry Distortions
Authors: Platero‐Prats Ana E. , Snejko Natalia , Iglesias Marta , Monge Ángeles , Gutiérrez‐Puebla Enrique 
Published: October 2013

AbstractWe propose a multidisciplinary approach to face the interpretation of heterogeneous catalysis with alkaline‐earth metal–organic frameworks (MOFs). Their oxygen‐based polyhedra, which do not exhibit regular geometries, do act as very active Lewis acid sites. Four novel alkaline‐earth MOFs that belong to three different structural types—Mg‐AEPF‐11, Mg‐APF‐12, Ca‐AEPF‐13 and Sr‐APF‐13—are reported, together with their net topologies, and a study of the symmetry distortions around the alkaline‐earth metal polyhedra by using a continuous shape mapping (CShM) description. These MOFs are good catalysts in the selective hydrogenation of styrene. Even more, Sr‐AEPF‐13 shows the best conversions ever published with alkaline‐earth MOFs for the hydrogenation of activated alkenes under mild conditions. A combination of crystallographic and topological analysis and theoretical calculations, together with experimental catalytic results, has been applied to understand the catalytic activity of these four novel alkaline‐earth MOFs. This work demonstrates that the presence of symmetry‐distorted alkaline‐earth polyhedra gives rise to highly catalytic‐active MOFs in the hydrogenation of activated alkenes.
Rhodium‐Catalyzed Oxidative C–H Activation/Cyclization for the Synthesis of Phosphaisocoumarins and Phosphorous 2‐Pyrones
Authors: Park Youngchul , Seo Jungmin , Park Sangjune , Yoo Eun Jeong , Lee Phil Ho 
Published: October 2013

AbstractRhodium‐catalyzed cyclization of phosphinic acids and phosphonic monoesters with alkynes has been developed. The oxidative annulation proceeds with complete conversion of phosphinic acid derivatives and allowed the atom‐economic preparation of useful phosphaisocoumarins with high yield and selectivity. The reaction is tolerant of extensive substitution on the phosphinic acid, phosphonic monoester and alkyne, including halides, ketone, and hydroxyl groups as substituents. Furthermore, we found that alkenylphosphonic monoesters proceed to give a wide range of phosphorus 2‐pyrones through oxidative annulation with alkynes. Mechanistic studies revealed that CH bond metalation was the rate‐limiting step.
Allosteric Indicator Displacement Enzyme Assay for a Cyanogenic Glycoside
Authors: Jose D. Amilan , Elstner Martin , Schiller Alexander 
Published: October 2013

AbstractIndicator displacement assays (IDAs) represent an elegant approach in supramolecular analytical chemistry. Herein, we report a chemical biosensor for the selective detection of the cyanogenic glycoside amygdalin in aqueous solution. The hybrid sensor consists of the enzyme β‐glucosidase and a boronic acid appended viologen together with a fluorescent reporter dye. β‐Glucosidase degrades the cyanogenic glycoside amygdalin into hydrogen cyanide, glucose, and benzaldehyde. Only the released cyanide binds at the allosteric site of the receptor (boronic acid) thereby inducing changes in the affinity of a formerly bound fluorescent indicator dye at the other side of the receptor. Thus, the sensing probe performs as allosteric indicator displacement assay (AIDA) for cyanide in water. Interference studies with inorganic anions and glucose revealed that cyanide is solely responsible for the change in the fluorescent signal. DFT calculations on a model compound revealed a 1:1 binding ratio of the boronic acid and cyanide ion. The fluorescent enzyme assay for β‐glucosidase uses amygdalin as natural substrate and allows measuring Michaelis–Menten kinetics in microtiter plates. The allosteric indicator displacement assay (AIDA) probe can also be used to detect cyanide traces in commercial amygdalin samples.
Enantio‐ and Diastereoconvergent Cyclocondensation Reactions: Synthesis of Enantiopure cis‐Decahydroquinolines
Authors: Amat Mercedes , Ghirardi Elena , Navío Laura , Griera Rosa , Llor Núria , Molins Elies , Bosch Joan 
Published: October 2013

AbstractUp to four stereocenters with a well‐defined configuration are generated in a single synthetic step by the cyclocondensation of (R)‐phenylglycinol or (1S,2R)‐1‐amino‐2‐indanol with stereoisomeric mixtures (racemates, meso forms, diastereoisomers) of cyclohexanone‐based δ‐keto‐acid and δ‐keto‐diacid derivatives in enantio‐ and diastereoconvergent processes that involve dynamic kinetic resolution and/or desymmetrization of enantiotopic groups. A detailed analysis of the stereochemical outcome of this process is presented. This method provides easy access to enantiopure 8‐ and 6,8‐substituted cis‐decahydroquinolines, including alkaloids of the myrioxazine family.
Difunctionalized {closo‐1‐CB11} Clusters: 1‐ and 2‐Amino‐12‐ethynylcarba‐closo‐dodecaborates
Authors: Hailmann Michael , Herkert Lorena , Himmelspach Alexander , Finze Maik 
Published: October 2013

AbstractCarba‐closo‐dodecaborate anions with two functional groups have been synthesized via a simple two‐step procedure starting from monoamino‐functionalized {closo‐1‐CB11} clusters. Iodination at the antipodal boron atom provided access to [1‐H2N‐12‐I‐closo‐1‐CB11H10]− (1 a) and [2‐H2N‐12‐I‐closo‐1‐CB11H10]− (2 a), which have been transformed into the anions [1‐H2N‐12‐RCC‐closo‐1‐CB11H10]− (R=H (1 b), Ph (1 c), Et3Si (1 d)) and [2‐H2N‐12‐RCC‐closo‐1‐CB11H10]− (R=H (2 b), Ph (2 c), Et3Si (2 d)) by microwave‐assisted Kumada‐type cross‐coupling reactions. The syntheses of the inner salts 1‐Me3N‐12‐RCC‐closo‐1‐CB11H10 (R=H (1 e), Et3Si (1 f)) and 2‐Me3N‐12‐RCC‐closo‐1‐CB11H10 (R=H (2 e), Et3Si (2 f)) are the first examples for a further derivatization of the new anions. All {closo‐1‐CB11} clusters have been characterized by multinuclear NMR and vibrational spectroscopy as well as by mass spectrometry. The crystal structures of Cs1 a, [Et4N]2 a, K1 b, [Et4N]1 c, [Et4N]2 c, 1 e, and [Et4N][1‐H2N‐2‐F‐12‐I‐closo‐1‐CB11H9]⋅0.5 H2O ([Et4N]4 a⋅0.5 H2O) have been determined. Experimental spectroscopic data and especially spectroscopic data and bond properties derived from DFT calculations provide some information on the importance of inductive and resonance‐type effects for the transfer of electronic effects through the {closo‐1‐CB11} cage.