bluuebunny/crossref_metadata_2025 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 Message

We 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

Manganese(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

Despite 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

The 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

The 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

The 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

The 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

Photoelectrochemical 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.
Comparison of interpolation polynomials with divided differences, interpolation polynomials with finite differences, and quadratic functions obtained by the least squares method in modeling of chromatographic responses
Authors: Rakić Tijana , Stanimirović Zorica , Đenić Aleksandar , Marić Miroslav , Jančić‐Stojanović Biljana , Medenica Mirjana
Published: October 2013

A novel approach to mathematical modeling of chromatographic responses based on interpolation polynomials with divided differences and with finite differences is discussed. These interpolational techniques as well as traditionally applied second‐order polynomial models obtained by least squares are compared. Interpolation techniques can be useful in situations where commonly used linear or quadratic models are not applicable: when the nature of dependence is complex or the investigated factor intervals are broad. The three analyzed modeling techniques are incorporated in a design of experiments methodology for systematic development and optimization of liquid chromatographic methods. The direct modeling of retention factors is carried out first, while the objective function for final quality measurement is calculated last. An interpolation polynomial with divided differences resulted in a high quality fit compared with the results obtained by the other two modeling approaches and succeeded in locating the desired optimum. It is shown that this modeling technique can be a useful alternative for modeling of chromatographic responses. Copyright © 2013 John Wiley & Sons, Ltd.
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

Integral 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

A 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

Nitrogen 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

The 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

A 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

New 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

We 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

Rhodium‐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

Indicator 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

Up 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

Carba‐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.
Gold‐Decorated Chiral Macroporous Films by the Self‐Assembly of Functionalised Block Copolymers
Authors: Suárez‐Suárez Silvia , Carriedo Gabino A. , Presa Soto Alejandro
Published: October 2013

We describe a new and very versatile method to place chosen chemical functionalities at the edge of the pores of macroporous materials. The method is based on the synthesis and self‐assembly of inorganic block copolymers (BCPs) having chiral rigid segments bearing controllable quantities of randomly distributed functional groups. The synthesis of a series of optically active block copolyphosphazenes (PP) with the general formula [NP(R‐O2C20H12)0.9(FG)0.2]n‐b‐[NPMePh]m (FG=‐OC5H4N (6), ‐NC4H8S (7), and ‐NC4H8O (8)), was accomplished by the sequential living cationic polycondensation of N‐silylphosphoranimines, using the mono‐end‐capped initiator [Ph3PNPCl3][Cl] (3). The self‐assembly of the phosphazene BCPs 6–8 led to chiral porous films. The functionality present on those polymers affected their self‐assembly behaviour resulting in the formation of pores of different diameters (Dn=111 (6), 53 (7) and 77 nm (8)). The specific functionalisation of the pores was proven by decorating the films with gold nanoparticles (AuNPs). Thus, the BCPs 6 and 7, having pyridine and thiomorpholine groups, respectively, were treated with HAuCl4, followed by reduction with NaBH4, yielding a new type of block copolyphosphazenes, which self‐assembled into chiral porous films specifically decorated with AuNPs at the edge of the pores.
Analysis of Oxcarbazepine and the 10‐Hydroxycarbazepine Enantiomers in Plasma by LC‐MS/MS: Application in a Pharmacokinetic Study
Authors: de Jesus Antunes Natalicia , Wichert‐Ana Lauro , Coelho Eduardo Barbosa , Della Pasqua Oscar , Alexandre Veriano , Takayanagui Osvaldo Massaiti , Tozatto Eduardo , Lanchote Vera Lucia
Published: October 2013

Oxcarbazepine is a second‐generation antiepileptic drug indicated as monotherapy or adjunctive therapy in the treatment of partial seizures or generalized tonic–clonic seizures in adults and children. It undergoes rapid presystemic reduction with formation of the active metabolite 10‐hydroxycarbazepine (MHD), which has a chiral center at position 10, with the enantiomers (S)‐(+)‐ and R‐(−)‐MHD showing similar antiepileptic effects. This study presents the development and validation of a method of sequential analysis of oxcarbazepine and MHD enantiomers in plasma using liquid chromatography with tandem mass spectrometry (LC‐MS/MS). Aliquots of 100 μL of plasma were extracted with a mixture of methyl tert‐butyl ether: dichloromethane (2:1). The separation of oxcarbazepine and the MHD enantiomers was obtained on a chiral phase Chiralcel OD‐H column, using a mixture of hexane:ethanol:isopropanol (80:15:5, v/v/v) as mobile phase at a flow rate of 1.3 mL/min with a split ratio of 1:5, and quantification was performed by LC‐MS/MS. The limit of quantification was 12.5 ng oxcarbazepine and 31.25 ng of each MHD enantiomer/mL of plasma. The method was applied in the study of kinetic disposition of oxcarbazepine and the MHD enantiomers in the steady state after oral administration of 300 mg/12 h oxcarbazepine in a healthy volunteer. The maximum plasma concentration of oxcarbazepine was 1.2 µg/mL at 0.75 h. The kinetic disposition of MHD is enantioselective, with a higher proportion of the S‐(+)‐MHD enantiomer compared to R‐(−)‐MHD and an AUC0‐12 S‐(+)/R‐(−) ratio of 5.44. Chirality 25:897–903, 2013. © 2013 Wiley Periodicals, Inc.
Auto‐Conveying Probing Apparatus for Extraction of Particle‐Free Samples from Process Gasses
Authors: Mescher Axel , Thönes Martin , Walzel Peter
Published: October 2013

Zur Inline‐Analyse der lokalen Gaszusammensetzung von Prozessströmen in Apparaten werden neben dem Analysegerät oftmals Filter zur Partikelabscheidung sowie Gasfördervorrichtungen zum Ausgleich des Messgeräte‐ und Filterdruckverlusts verwendet. Die Wechselwirkung des zu analysierenden Gases mit dem Filterkuchen kann den Messwert durch zusätzlichen Stoff‐ und Wärmetransport oder im Falle reaktiver Systeme durch zusätzlichen Reaktionsfortschritt beeinflussen. In der vorliegenden Arbeit wird ein im Versuchsbetrieb bewährter Sondenprototyp zur Gasprobenentnahme vorgestellt. Der Apparat stellt einerseits selbstansaugend einen Gasstrom zur Analyse bereit und erlaubt es, Partikel bereits am Ort der Probennahme nach dem Prinzip eines Abweiseradsichters abzutrennen.
Propylene/Propane Separation in Fixed‐Bed Adsorber and Membrane Permeation
Authors: Mundstock Alexander , Böhme Ulrike , Barth Benjamin , Hartmann Martin , Caro Jürgen
Published: October 2013

Die metallorganische Gerüstverbindung Mg2(dhtp) mit dem Linker Dihydroxyterephthalat ist als MOF‐74 oder CPO‐27 bekannt. Mg2(dhtp) wurde in Pulverform für die Messung von Durchbruchskurven im Festbettadsorber und Adsorptionsisothermen sowie als geträgerte dünne Membranschicht für Permeationsmessungen synthetisiert. Die Messung der Durchbruchskurven des binären Propylen/Propan‐Gemisches zeigt, dass eine Trennung im Festbettadsorber möglich ist. Es zeigt sich hier eine höhere Affinität des Propylens zum Adsorbens Mg2(dhtp). Obwohl der Einzelgasfluss von Propan höher als der von Propylen ist, weist die Mg2(dhtp)‐Membran für das binäre Gemisch kein Trennverhalten auf.
Kieselalgen
Authors: Groß Michael
Published: October 2013

Kieselalgen (Diatomeen) stellen eine höchst ungewöhnliche Organismengruppe dar. Sie erwarben den Photosynthese‐Apparat erst viel später als die Pflanzen. Erst vor 200 Millionen Jahren begann ihr rasanter Aufstieg, der ihnen starken Einfluss auf die geochemischen Zyklen und das Erdklima verlieh. Auch die in den vergangenen Jahren oft diskutierte Idee, Kohlendioxid durch Eisendüngung der Ozeane zu binden, zielt auf die Kieselalgen ab, da diese auf Nährstoffeintrag am schnellsten reagieren. Ihre feinziselierten Glasschalen interessieren auch die Nanotechnologen. Da die Kieselalgen in keine der traditionellen Schubladen der Wissenschaften hineinpassen und keinen gut untersuchten Modellorganismus haben, ist die Morphogenese dieser Schalen bisher unzureichend verstanden und kann noch nicht im Labor nachvollzogen werden.
Unsteady heat and mass transfer by MHD mixed convection flow from a rotating vertical cone with chemical reaction and Soret and Dufour effects
Authors: Chamkha Ali J. , Rashad A. M.
Published: October 2013

This work focused on the study of Soret and Dufour effects on unsteady coupled heat and mass transfer by mixed convection flow over a vertical cone rotating in an ambient fluid with a time‐dependent angular velocity in the presence of a magnetic field and chemical reaction. The cone surface is maintained at variable temperature and concentration. The resulting governing equations are non‐dimensionalised and transformed into a non‐similar form and then solved numerically by an implicit, iterative, finite‐difference method. Comparisons with previously published work are performed and excellent agreement is obtained. A parametric study showing the effects of the buoyancy parameter, magnetic field, chemical reaction parameter, Soret and Dufour numbers on the local tangential and azimuthal skin friction coefficients, and the local Nusselt and Sherwood numbers are conducted. These results are illustrated graphically to depict special features of the solutions.
Pumping characterisation of the maxblend impeller for Newtonian and strongly non‐Newtonian fluids
Authors: Stobiac Vincent , Fradette Louis , Tanguy Philippe A. , Bertrand Francois
Published: October 2013

This paper examines the pumping mechanisms generated by the Maxblend impeller. Simulation results obtained with the lattice Boltzmann method (LBM) are presented for Newtonian fluids (Re = 2–140) and strongly shear‐thinning fluids (Reg = 0.1–50) obeying the Carreau–Yasuda model with a very small power index (n = 0.05). In the Newtonian case, the pumping numbers predicted by the LBM are shown to compare favourably to those obtained with the finite element (FEM) as well as to experimental data based on the decolourisation method. These results indicate a small pumping capacity in the deep laminar regime followed by its sharp increase in the transitional regime, a phenomenon which is explained by examining the flow field simulated with the LBM and the FEM and measured through PIV. In the case of the strongly shear thinning fluids, the impact of the rheology on pumping is investigated. The flow fields and so‐called pumping volumes predicted with the LBM reveal, similarly to the Newtonian case, a change in the structure of the axial and (secondary) radial flow when the Reynolds number is increased. Viscosity contours suggest that this phenomenon is in fact related to the occurrence of zones with very different apparent viscosities, which explains the problematic flow patterns observed experimentally with the PIV.
Potential for flammability of gases emitted from stored wood pellets
Authors: Yazdanpanah Fahimeh , Sokhansanj Shahab , Lim Jim , Lau Anthony , Bi Xiaotao , Lam Pak Yiu , Melin Staffan
Published: October 2013

Previous measurements have shown that freshly made wood pellets continued to emit flammable gases such as CO, H2 and CH4 during storage and handling. The research reported in this paper examines whether the concentration of these emitted gases and the available oxygen within enclosed wood pellet spaces can reach flammable levels. Glass jars filled to 75% volume with pellets were sealed and placed in controlled environments at 25, 40 and 60°C for a period of 9 weeks. Each batch of the stored pellet had a moisture content of 4%, 9%, 15%, 35% or 50% (wet mass basis). The concentrations of carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), oxygen (O2), nitrogen (N2) and hydrogen (H2) were determined using gas chromatography. The flammability of the gas mixtures in the container headspace was calculated using ISO 10156 Standard ‘Gases and gas mixtures—Determination of fire and oxidizing ability for selection of cylinder valve outlets.’ It was concluded that the composition of the gas mixture does not reach flammable concentrations under all experimental conditions.
Kinetic analysis on thermo‐gravimetric profiles of pulverised coal pyrolysis and gasification under different oxy‐fuel environments
Authors: Irfan Muhammad Faisal , Chakrabarti Mohammed Harun , Kusakabe Katsuki
Published: October 2013

Reactivity analysis of pulverised coal in O2/N2/CO2 environments was carried out using thermo‐gravimetric method. At all temperature ranges, coal combustion in O2/CO2 and O2/N2 environments using equivalent oxygen concentrations was almost similar. However, when oxygen concentration increased the coal burning rate also increased thus reducing the burnout time and net combustion gas volume. With increasing heating rate, coal particles burnt at shorter times and at higher temperatures. Mathematical models of Doyle, Coats–Redfern and Freeman–Carroll were applied to determine activation energy and pre‐exponential factor of oxy‐coal combustion at various heating rates. However, kinetic parameters decreased when heating rates increased from 10 to 50 K/min.
DNA Binding and Oxidative Cleavage by a Water‐soluble Carboxyl Manganese(III) Corrole
Authors: Zhang Yang , Wang Qi , Wen Jinyan , Wang Xiangli , Mahmood Mian HR , Ji Liangnian , Liu Haiyang
Published: October 2013

The interaction of calf thymus DNA (CT DNA) and water‐soluble manganese corrole, 5,10,15‐tris(4‐carboxyphenyl)corrolatomanganese(III) (MnIIITCPC) has been studied by absorption spectra, fluorescence spectra and CD spectra, as well as by viscosity measurements. Results revealed that this manganese corrole binds to CT DNA via an outside groove binding mode with intrinsic binding constant Kb of 4.67×104 L·mol−1. DNA cleavage activities of MnIIITCPC in the presence of various oxidants were also investigated. MnIIITCPC can cleave the supercoiled plasmid pBR322 DNA to both nicked and linear form in the presence of hydrogen peroxide or tert‐BuOOH, while no nuclease activity was observed by using KHSO5 as oxidant. Inhibitor tests revealed that hydroxyl radicals or singlet oxygen was not involved in MnIIITCPC mediated DNA oxidative cleavage. It is suggested that (oxo)manganese(V) corrole is the possibly active intermediate in this oxidative cleavage reactions.
New Core‐Expanded Naphthalene Diimides for n‐Channel Organic Thin Film Transistors
Authors: Hu Yunbin , Wang Zhongli , Zhang Xu , Yang Xiaodi , Li Hongxiang , Gao Xike
Published: October 2013

Four classes of core‐expanded naphthalene diimides (1a, 1b, 2a, 2b, 3 and 4) that bear different electron‐deficient sulfur heterocycles were designed and synthesized. The solution‐processed thin films of 1a, 2a, 3 and 4 operated well in air as n‐channel organic transistors with electron mobility ranging from ∼10−6 to 0.14 cm2/Vs, depending on the different conjugated backbones. The thin film microstructure studies were also carried out to understand the variations of the electron mobility for thin films of 1a, 2a, 3 and 4.
Simultaneous fixed and random effects selection in finite mixture of linear mixed‐effects models
Authors: Du Yeting , Khalili Abbas , Nešlehová Johanna G. , Steele Russell J.
Published: October 2013

In this article, we study finite mixtures of linear mixed‐effects (FMLME) models that are useful for longitudinal regression modelling in the presence of heterogeneity in both fixed and random effects. These models are computationally challenging when the number of covariates is large, and traditional variable selection techniques become expensive to implement. We introduce a penalized likelihood approach, and propose a nested EM algorithm for efficient numerical computations. The resulting estimators are shown to possess consistency and sparsity properties, and to be asymptotically normally distributed. We illustrate the performance of our method through simulations and a real data example. The Canadian Journal of Statistics 41: 596–616; 2013 © 2013 Statistical Society of Canada
Graphical and formal statistical tools for the symmetry of bivariate copulas
Authors: Quessy Jean‐François , Bahraoui Tarik
Published: October 2013

Statistical tools to check whether the underlying copula of a pair of random variables is symmetric are developed. The proposed methods are based on the theoretical and empirical versions of the C‐power functions introduced and formally studied by Bahraoui & Quessy (2013). On one part, a methodology is developed for testing the null hypothesis that the copula of a given population is symmetric. To this end, a sequential testing procedure is proposed where at each level, the P‐value is estimated with the help of the multiplier bootstrap method. On another side, a related graphical method is proposed in order to gain an idea of the degree of asymmetry in bivariate data. The good properties of the methods in small samples are investigated with the help of Monte Carlo simulations under various scenarios of symmetric and asymmetric dependence. The newly introduced procedures are used to analyse the Nutrient and the Walker Lake data sets. The Canadian Journal of Statistics 41: 637–656; 2013 © 2013 Statistical Society of Canada
Robust estimation of distribution functions and quantiles with non‐ignorable missing data
Authors: Zhao Pu‐Ying , Tang Man‐Lai , Tang Nian‐Sheng
Published: October 2013

This paper considers several robust estimators for distribution functions and quantiles of a response variable when some responses may not be observed under the non‐ignorable missing data mechanism. Based on a particular semiparametric regression model for non‐ignorable missing response, we propose a nonparametric/semiparametric estimation method and an augmented inverse probability weighted imputation method to estimate the distribution function and quantiles of a response variable. Under some regularity conditions, we derive asymptotic properties of the proposed distribution function and quantile estimators. Two empirical log‐likelihood functions are also defined to construct confidence intervals for distribution function of a response variable. Simulation studies show that our proposed methods are robust. In particular, the semiparametric estimator is more efficient than the nonparametric estimator, and the inverse probability weighted imputation estimator is bias‐corrected.The Canadian Journal of Statistics41: 575–595; 2013 © 2013 Statistical Society of Canada
Associations Between Sleep Duration and Prevalence of Cardiovascular Events
Authors: Aggarwal Saurabh , Loomba Rohit Seth , Arora Rohit Romesh , Molnar Janos
Published: October 2013

Background

Data regarding the associations between sleep duration and clinical cardiovascular (CV) events are limited. We aimed to analyze any associations between self‐reported sleep duration and CV events.

Hypothesis

Methods

This is a cross‐sectional analysis of nationally representative population of noninstitutionalized US civilians recruited in the 2007 to 2008 National Health and Nutrition Examination Survey. This is a questionnaire‐based study including only those subjects who answered questions on sleep duration and CV events. The main outcome measures were prevalence of congestive heart failure, myocardial infarction, stroke, coronary artery disease, and angina.

Results

After logistic regression analysis, significant associations between sleep duration and prevalence of stroke, myocardial infarction, congestive heart failure, coronary artery disease, and angina were found. There was a statistically significant increase in stroke in those with <6 hours of sleep (odds ratio [OR]: 2.0111, 95% confidence interval [CI]: 1.4356‐2.8174), in myocardial infarction in those with <6 hours of sleep (OR: 2.0489, 95% CI: 1.4878‐2.8216), in congestive heart failure in those with <6 hours of sleep (OR: 1.6702, 95% CI: 1.1555 to 2.4142), in coronary artery disease in those with >8 hours of sleep (OR: 1.1914, 95% CI: 1.0712‐3.4231), and in angina in those with >8 hours of sleep (OR: 2.0717, 95% CI: 1.0497‐4.0887).

Conclusions

The results of this cross‐sectional analysis suggest that sleep duration may be associated with the prevalence of various CV events.
Projected Costs and Consequences of Computed Tomography‐Determined Fractional Flow Reserve
Authors: Hlatky Mark A. , Saxena Akshay , Koo Bon‐Kwon , Erglis Andrejs , Zarins Christopher K. , Min James K.
Published: October 2013

Background

Randomized trials have shown that fractional flow reserve (FFR) guided percutaneous coronary intervention (PCI) improves clinical outcome and reduces costs compared with visually guided PCI. FFR has been measured during invasive coronary angiography (ICA), but can now be derived noninvasively from coronary computed tomography (CT) angiography (cCTA) images (FFRCT). The potential value of FFRCT in clinical decision making is unknown.

Hypothesis

Use of FFRCT can reduce costs and improve outcomes among patients with suspected coronary artery disease.

Methods

We used clinical data from 96 patients in the DISCOVER‐FLOW (Diagnosis of Ischemia‐Causing Stenoses Obtained Via Noninvasive Fractional Flow Reserve) study and outcomes data from the literature to project the initial management costs and 1‐year death/myocardial infarction rates associated with 5 clinical strategies: (1) ICA with PCI based on visual angiographic assessment, (2) ICA with FFRICA‐guided PCI, (3) cCTA followed by ICA and PCI based on visual assessment, (4) cCTA followed by ICA with FFRICA‐guided PCI, and (5) cCTA FFRCT and PCI of lesions with FFRCT ≤0.80.

Results

The projected initial management costs were highest for the ICA/visual strategy ($10 702), and lowest for the cCTA/FFRCT/ICA strategy ($7674). The use of FFRCT to select patients for ICA and PCI would result in 30% lower costs and 12% fewer events at 1 year compared with the most commonly used ICA/visual strategy.

Conclusions

A strategy of using FFRCT to guide the selection of patients for ICA and PCI might reduce costs and improve clinical outcomes in patients with suspected coronary artery disease.
Adiponectin Levels Are Elevated in Patients With Pulmonary Arterial Hypertension
Authors: Santos Mário , Reis Abílio , Gonçalves Fabienne , Ferreira‐Pinto Manuel J. , Cabral Sofia , Torres Severo , Leite‐Moreira Adelino F. , Henriques‐Coelho Tiago
Published: October 2013

Background

In addition to insulin‐sensitizing effects, adiponectin influences several mechanisms involved in pulmonary arterial hypertension (PAH) pathobiology. Insulin resistance has been associated with PAH, and elevated adiponectin levels have been described in left heart failure (HF) as a response to the increased metabolic stress. No studies have been performed in right HF or PAH patients.

Hypothesis

Compared to healthy controls, PAH patients have a different plasma adipocytokine profile, higher insulin resistance, and higher inflammatory systemic activation.

Methods

A case–control study was conducted in PAH patients individually matched for sex, age, and body mass index. We characterized the clinical features, functional status (6‐minute walking test), and hemodynamic profile of cases (n = 25). We measured insulin resistance (homeostasis model assessment and high‐density lipoprotein/triglycerides ratio), inflammatory systemic activation (high‐sensitivity C‐reactive protein), and plasma adipocytokine profile (adiponectin, leptin, visfatin, and resistin) in cases and controls.

Results

PAH patients had significantly higher adiponectin levels than controls (12.4 ± 6.9 vs 8.1 ± 4.5 µg/mL; P < 0.05) and higher high‐sensitivity C‐reactive protein (2.96 ± 3.2 vs 1.08 ± 1.1; P < 0.05). No statistically significant differences were found in plasma levels of leptin, visfatin, and resistin between groups.

Conclusions

Adiponectin levels are increased in PAH patients compared to controls. Further studies are needed to study the potential role of adiponectin as a PAH biomarker.