bluuebunny/crossref_metadata_2025 huggingface dataset:
Aqueous‐Phase Hydrogenation of Saturated and Unsaturated Ketones and Aldehydes over Supported Platinum–Rhenium Catalysts
Authors: Falcone Derek D. , Hack John H. , Davis Robert J.
Published: February 2016

The hydrogenation rates of C=C and C=O bonds in methyl vinyl ketone and crotonaldehyde were measured over a series of silica‐supported Pt‐Re catalysts (1:1 atomic ratio of Pt/Re) in liquid water with H2 (15 psig) at 333 K. The hydrogenation of methyl vinyl ketone did not produce any unsaturated alcohol because of the rapid hydrogenation of C=C relative to that of C=O. The addition of Re to Pt impacted the rate of C=C hydrogenation negatively in methyl vinyl ketone and crotonaldehyde, but promoted the selectivity of C=O hydrogenation in crotonaldehyde in which the unsaturated alcohol increased from 5 % on Pt to 21 % on Pt‐Re. The addition of Re to Pt also promoted the rate of C=O hydrogenation in 2‐butanone, whereas little effect was observed during the hydrogenation of butanal. The results of electron microscopy and H2 chemisorption on the Pt‐Re catalysts showed the increasing interaction between Pt and Re with the increasing metal weight loading, and results from rate measurements suggest that oxophilic Re can be used to promote the Pt‐catalyzed hydrogenation of carbonyl groups in multifunctional molecules.
Controlling the Morphology and Efficiency of Nanostructured Molybdenum Nitride Electrocatalysts for the Hydrogen Evolution Reaction
Authors: Ojha Kasinath , Saha Soumen , Kumar Bharat , Hazra Kiran Shankar , Ganguli Ashok K.
Published: February 2016

Among catalysts based on non‐noble metals, Mo‐based materials are important for hydrogen evolution because of their low cost, good conductivity, and catalytic efficiency. This study demonstrates a facile two‐step synthesis of Mo2N nanostructures assembled from 5–8 nm particles with graphitic carbon nitride as the nitrogen source. These Mo2N nanostructures of various morphologies (hexagons, triangles, and nanowires) show a very high activity and stability in acidic media during water electrolysis. Their nanostructures were characterized by using powder XRD, electron microscopy, N2 gas adsorption analysis, and X‐ray photoelectron spectroscopy. Hydrogen evolution reaction parameters, which include the Tafel slope, charge transfer resistance, and stability, were analyzed by using linear sweep voltammetry and electrochemical impedance spectroscopy. Thin hexagonal sheets of Mo2N show the highest apparent electrocatalytic activity (current density of 197 mA cm−2geometric at −400 mV vs. the reversible hydrogen electrode) and excellent stability in an acidic medium with a small onset potential of 90 mV and a Tafel slope of 145 mV decade−1. The lowest Tafel slope was observed for Mo2N nanowires.
Acylation of β‐Amino Esters and Hydrolysis of β‐Amido Esters: Candida antarctica Lipase A as a Chemoselective Deprotection Catalyst
Authors: Mäenpää Harri , Kanerva Liisa T. , Liljeblad Arto
Published: February 2016

N‐Acylation by lipase A from Candida antarctica (CAL‐A) in ethyl butanoate was applied to the kinetic resolution of tert‐butyl esters of 3‐amino‐3‐phenylpropanoic acid (E>100), 3‐amino‐4‐methylpentanoic acid (E>100) and 3‐aminobutanoic acid (E=60) on 1.0–2.0 m scale. With the N‐acylated resolution products, the exceptional ability of CAL‐A to hydrolyse amides and bulky tert‐butyl esters was then studied. In all N‐acylated tert‐butyl esters, chemoselectivity favoured the amide bond cleavage. The tert‐butyl ester bond was left intact with 3‐amino‐3‐phenylpropanoate, whereas with 3‐amino‐4‐methylpentanoate and 3‐aminobutanoate the CAL‐A‐catalysed hydrolysis of tert‐butyl ester followed the amide hydrolysis.
Copper‐Fiber‐Structured Pd–Au–CuOx: Preparation and Catalytic Performance in the Vapor‐Phase Hydrogenation of Dimethyl Oxalate to Ethylene Glycol
Authors: Han Lupeng , Zhang Li , Zhao Guofeng , Chen Yanfei , Zhang Qiaofei , Chai Ruijuan , Liu Ye , Lu Yong
Published: February 2016

Cu‐fiber‐structured ternary Pd–Au–CuOx catalysts engineered from nano‐ to macro‐scales have been developed for the vapor‐phase dimethyl oxalate (DMO) hydrogenation to ethylene glycol (EG), with the aid of galvanic deposition of Pd and Au onto a thin‐sheet microfibrous structure using 8 μm Cu fiber. Effects of Pd and Au loadings and their ratio have been investigated on the catalyst performance as well as the reaction conditions including reaction temperature and pressure, liquid weight hourly space velocity, and H2/DMO ratio. The promising 0.1 Pd–0.5 Au–CuOx/Cu‐fiber catalyst is capable of converting 97–99 % DMO into EG product at a selectivity of 90–93 %. This catalyst is stable for at least 200 h. The Pd–Au–Cu2O synergistically promotes the hydrogenation activity and stabilizes Cu+ sites to suppress deep reduction deactivation.
Branched Selectivity in the Pd‐Catalysed Methoxycarbonylation of 1‐Alkenes
Authors: Arderne Charmaine , Guzei llia A. , Holzapfel Cedric W. , Bredenkamp Tyler
Published: February 2016

The methoxycarbonylation of alkenes by palladium(II) complexes with P,O‐donor ligands [(2‐methoxyphenyl)diphenylphosphine (L‐2), bis(2‐methoxyphenyl) phenyl phosphine (L‐3) and tris(2‐methoxyphenyl) phosphine (L‐4)] has been investigated. The results show that the Pd complexes derived from these ligands provide high regioselectivity for the branched esters from 1‐pentene and 1‐hexene (>80 %). Various parameters (including temperature, pressure, acid concentration) were optimized to improve the performance of the catalyst system. Higher temperatures afforded higher regioselectivity; but effected rapid catalyst decomposition. Acceptable turnover frequencies, conversions as well as catalyst stability could be obtained at higher L/Pd ratios. The dramatic change in regioselectivity is rationalised on the basis of the hemi‐lability of the o‐methoxy moiety, which may lead to ligand dissociation from L2PdX2 (L=ligand, X=Cl) rather than the expected dissociation of X. In support of our hypothesis, direct evidence for the coordination of the o‐methoxy to the Pd centre was demonstrated by the crystal structure. To the best of our knowledge, this work provides the first reported route to valuable branched esters through the methoxycarbonylation of alkenes at suitable rates.
Putrescine Transaminases for the Synthesis of Saturated Nitrogen Heterocycles from Polyamines
Authors: Slabu Iustina , Galman James L. , Weise Nicholas J. , Lloyd Richard C. , Turner Nicholas J.
Published: February 2016

Putrescine transaminase (pATA; EC 2.6.1.82) catalyzes the transfer of an amino group from terminal diamine donor molecules to keto acid acceptors by using pyridoxal‐5′‐phosphate as a cofactor. The ygjG genes from Escherichia coli K12, Bacillus megaterium, and Bacillus mycoides were successfully cloned and expressed in E. coli BL21(DE3) cells. The three putrescine transaminases were all shown to prefer diaminoalkanes as substrates and thereby generated cyclic imines from the ω‐amino aldehyde intermediates. The addition of a mild chemical reducing agent rapidly reduced the imine intermediate in situ to furnish a range of N‐heterocycle products. We applied pATA in a biomimetic synthesis of 2,3‐dihydro‐1H‐indolizinium‐containing targets, notably the bioactive alkaloid ficuseptine.
Engineering the Morphology of Carbon Materials: 2D Porous Carbon Nanosheets for High‐Performance Supercapacitors
Authors: Yuan Kai , Hu Ting , Xu Yazhou , Graf Robert , Brunklaus Gunther , Forster Michael , Chen Yiwang , Scherf Ullrich
Published: February 2016

Compared with traditional porous carbon materials, two‐dimensional (2D) porous carbon materials with a high aspect ratio and a continuous hierarchical porous structure are promising candidates for the construction of supercapacitor electrode materials. Herein, well‐defined, graphene‐based conjugated microporous polymer sheets (G‐CMPs) were prepared in a graphene‐inspired synthetic strategy. Thereby, 4‐iodophenyl‐substituted graphene (RGO‐I) templates not only effectively hinder the aggregation between the adjacent graphene layers but also provide an efficient template for the growth of porous CMPs onto the graphene surface. Moreover, our G‐CMPs could be converted into 2D porous carbon nanosheets by pyrolysis. The synergism of high aspect ratio and high specific surface area, the presence of graphene‐based conduction paths and hierarchical pore systems ensure a high ion‐accessible surface area of the corresponding supercapacitor electrodes thus allowing accelerated electron and ion diffusion/transport and leading to high specific capacitance as well as good rate capability and cycling stability.
Strongly Coupled Architectures of Cobalt Phosphide Nanoparticles Assembled on Graphene as Bifunctional Electrocatalysts for Water Splitting
Authors: Huang Huawei , Yu Chang , Yang Juan , Zhao Changtai , Han Xiaotong , Liu Zhibin , Qiu Jieshan
Published: February 2016

Efficient bifunctional electrocatalysts for both the cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) are crucial for water splitting in a sustainable energy system. A strategy for fabricating strongly coupled cobalt phosphide (CoP)/graphene (G) architectures composed of CoP nanoparticles and G is described. Benefiting from synergetic effects of a dual support system of CoP for electroactive sites and G to enhance charge transfer, low overpotentials of 120 mV for the HER (0.5 m H2SO4) and 292 mV for the OER (1 m KOH) are required to achieve current densities of 10 mA cm−2. The as‐prepared CoP/G composites, which serve as bifunctional catalysts for both HER and OER in complete water splitting, can generate a current density of 10 mA cm−2 at 1.626 V. The present strategy provides a novel and efficient method for configuring high‐efficiency electrocatalysts for energy‐related storage and conversion devices.
Radical Cyclisation of α‐Halo Aluminium Acetals: A Mechanistic Study
Authors: Bénéteau Romain , Boussonnière Anne , Rouaud Jean‐Christophe , Lebreton Jacques , Graton Jérôme , Jacquemin Denis , Sebban Muriel , Oulyadi Hassan , Hamdoun Ghanem , Hancock Amber N. , Schiesser Carl H. , Dénès Fabrice
Published: February 2016

α‐Bromo aluminium acetals are suitable substrates for Ueno–Stork‐like radical cyclisations affording γ‐lactols and acid‐sensitive methylene‐γ‐lactols in high yields. The mechanistic study herein sets the scope and limitation of this reaction. The influence of the halide (or chalcogenide) atom X (X=Cl, Br, I, SPh, SePh) in the precursors α‐haloesters, as well as influence of the solvent and temperature was studied. The structure of the aluminium acetal intermediates resulting from the reduction of the corresponding α‐haloesters has been investigated by low‐temperature 13C‐INEPT diffusion‐ordered NMR spectroscopy (DOSY) experiments and quantum calculations, providing new insights into the structures of these thermally labile intermediates. Oxygen‐bridged dimeric structures with a planar Al2O2 ring are proposed for the least hindered aluminium acetals, while monomeric structures seem to prevail for the most hindered species. A comparison against the radical cyclisation of aluminium acetals derived from allyl and propargyl alcohols with the parent Ueno–Stork has been made at the BHandHLYP/6‐311++G(d,p) level of theory, highlighting mechanistic similarities and differences.
Synthesis of Redshifted Azobenzene Photoswitches by Late‐Stage Functionalization
Authors: Konrad David B. , Frank James A. , Trauner Dirk
Published: February 2016

Azobenzenes are versatile photoswitches that can be cycled between their trans‐ and cis‐configuration with light. The wavelengths required for this isomerization are substantially shifted from the UV to the visible range through tetra‐ortho‐chlorination. These halogenated azobenzenes display unique photoswitching characteristics, but their syntheses remain limited and inefficient. A new general method for the synthesis of tetra‐ortho‐chloro azobenzenes has been developed, which relies on direct palladium(II)‐catalyzed C−H activation of pre‐existing standard azobenzenes. This late‐stage functionalization has a broad substrate scope and can be used to create a variety of useful building blocks for the construction of more elaborate redshifted photopharmaceuticals. This method is used to prepare red‐AzCA‐4, a photoswitchable vanilloid that enables optical control of the cation channel TRPV1 with visible light.
Why Are Women Underrepresented in STEM Fields?
Authors: Nimmesgern Hildegard
Published: February 2016

Women are still underrepresented in the so‐called “hard” fields of science, technology, engineering, and mathematics (STEM). In this Guest Editorial, H. Nimmesgern, Chairwoman of the Arbeitskreis Chancengleichheit in der Chemie (AKCC), a working group of the German Chemical Society (GDCh), describes the challenges women in science face and organizations that have been set up to help them in their research careers.
Multimetallic Architectures from the Self‐assembly of Amino Acids and Tris(2‐pyridylmethyl)amine Zinc(II) Complexes: Circular Dichroism Enhancement by Chromophores Organization
Authors: Badetti Elena , Wurst Klaus , Licini Giulia , Zonta Cristiano
Published: February 2016

Stereodynamic optical probes are becoming very popular for their capability to act as molecular sensors for the determination of the enantiomeric excess (ee) of chiral compounds. Herein, we describe a new molecular architecture formed by the self‐assembly of three zinc metal ions, two modified tris(2‐pyridylmethyl)amine ligands, and two amino acids. This system is the structural and functional serendipitous evolution of our previous probe for the determination of amino acids ee. In the new system, one of the metals templates in close proximity two chromophores enhancing their exciton coupling.
Piling Up Pillar[5]arenes To Self‐Assemble Nanotubes
Authors: Nierengarten Iwona , Guerra Sebastiano , Ben Aziza Haifa , Holler Michel , Abidi Rym , Barberá Joaquín , Deschenaux Robert , Nierengarten Jean‐François
Published: February 2016

New liquid‐crystalline pillar[5]arene derivatives have been prepared by grafting first‐generation Percec‐type poly(benzylether) dendrons onto the macrocyclic scaffold. The molecules adopt a disc‐shaped structure perfectly suited for self‐organization into a columnar liquid‐crystalline phase. In this way, the pillar[5]arene cores are piled up, thus forming a nanotubular wire encased within a shell of peripheral dendrons. The capability of pillar[5]arenes to form inclusion complexes has been also exploited. Specifically, detailed binding studies have been carried out in solution with 1,6‐dicyanohexane as the guest. Inclusion complexes have also been prepared in the solid state. Supramolecular organization into the Colh mesophase has been deduced from X‐ray diffraction data and found to be similar to that observed within the crystal lattice of a model inclusion complex prepared from 1,4‐dimethoxypillar[5]arene and 1,6‐dicyanohexane.
Alkyne Difunctionalization by Dual Gold/Photoredox Catalysis
Authors: Tlahuext‐Aca Adrian , Hopkinson Matthew N. , Garza‐Sanchez R. Aleyda , Glorius Frank
Published: February 2016

Highly selective tandem nucleophilic addition/cross‐coupling reactions of alkynes have been developed using visible‐light‐promoted dual gold/photoredox catalysis. The simultaneous oxidation of AuI and coordination of the coupling partner by photo‐generated aryl radicals, and the use of catalytically inactive gold precatalysts allows for high levels of selectivity for the cross‐coupled products without competing hydrofunctionalization or homocoupling. As demonstrated in representative arylative Meyer–Schuster and hydration reactions, this work expands the scope of dual gold/photoredox catalysis to the largest class of substrates for gold catalysts and benefits from the mild and environmentally attractive nature of visible‐light activation.
Char combustion of ellipsoidal particles in a hot gas with fluctuating temperature
Authors: Li Jie , Zhang Jian
Published: February 2016

Char combustion of biomass particles is a significant thermo‐chemical conversion process. The char combustion process of biomass particles with gas temperature fluctuation is numerically investigated. Considering the non‐spherical shape of biomass particles, a fully algebraic expression of burning enhancement factor is theoretically derived to modify the char combustion rate of ellipsoidal particles. Four solid biofuel samples (cynara, pinewood, willow, and cardoon) are chosen for the calculations. The instantaneous mass variations and char combustion rates of biomass particles are calculated under different particle sphericities. Different kinetic parameters of biomass samples lead to various effects of gas temperature fluctuation on char combustion. The gas temperature fluctuation generally enhances the char combustion rate. Increasing the fluctuation frequency of gas temperature has no effect on char combustion. Under the same particle surface area, the char combustion rate is enhanced with decreasing particle sphericity.
Small‐Molecule CD4 Mimics Containing Mono‐cyclohexyl Moieties as HIV Entry Inhibitors
Authors: Ohashi Nami , Harada Shigeyoshi , Mizuguchi Takaaki , Irahara Yu , Yamada Yuko , Kotani Misato , Nomura Wataru , Matsushita Shuzo , Yoshimura Kazuhisa , Tamamura Hirokazu
Published: February 2016

CD4 mimics are small molecules that inhibit the protein–protein interaction between gp120 and CD4, which is a key interaction for the entry of human immunodeficiency virus (HIV) into host immune cells. In the present study, mono‐cyclohexyl‐type CD4 mimics were designed to form hydrophobic and electrostatic interactions with Val430 and Asp368 located in the entrance of the Phe43 cavity of gp120, the interaction site of CD4. YIR‐329, a novel 1‐azaspiro[5.5]undecane derivative with a cyclohexyl ring attached to the piperidine ring, exhibited only slightly weaker anti‐HIV activity than a previously described lead HAR‐171, and modeling results indicated the formation of advantageous interactions by the para‐chlorophenyl moiety of YIR‐329. To introduce an electrostatic interaction with Asp368, derivatives with a guanidino group on the piperidine nitrogen atom were synthesized. Mono‐cyclohexyl‐type CD4 mimics with a guanidino group, such as YIR‐819 (N1‐(4‐chlorophenyl)‐N2‐(1‐(2‐(N‐(amidino)glycinamide)ethyl)‐2‐cyclohexylpiperidin‐4‐yl)oxalamide) and YIR‐821 (1‐(2‐(5‐guanidinovaleramide)ethyl derivative of YIR‐819), were identified that exhibit approximately fivefold more potent anti‐HIV activity than YIR‐329. In combination with a neutralizing antibody, their anti‐HIV activities were augmenting. Modeling results suggest that these compounds interact effectively with Val430 and either Asp368 or Asp474 in the gp120 Phe43 cavity. YIR‐819 and YIR‐821 represent useful lead compounds for the further development of HIV‐1 entry inhibitors and could potentially be useful for co‐administration with neutralizing antibodies for the treatment of HIV infection and AIDS.
Multi‐scale finite element modeling of Eustachian tube function: influence of mucosal adhesion
Authors: Malik J. E. , Swarts J. D. , Ghadiali S. N.
Published: February 2016

The inability to open the collapsible Eustachian tube (ET) leads to the development of chronic Otitis Media (OM). Although mucosal inflammation during OM leads to increased mucin gene expression and elevated adhesion forces within the ET lumen, it is not known how changes in mucosal adhesion alter the biomechanical mechanisms of ET function. In this study, we developed a novel multi‐scale finite element model of ET function in adults that utilizes adhesion spring elements to simulate changes in mucosal adhesion. Models were created for six adult subjects, and dynamic patterns in muscle contraction were used to simulate the wave‐like opening of the ET that occurs during swallowing. Results indicate that ET opening is highly sensitive to the level of mucosal adhesion and that exceeding a critical value of adhesion leads to rapid ET dysfunction. Parameter variation studies and sensitivity analysis indicate that increased mucosal adhesion alters the relative importance of several tissue biomechanical properties. For example, increases in mucosal adhesion reduced the sensitivity of ET function to tensor veli palatini muscle forces but did not alter the insensitivity of ET function to levator veli palatini muscle forces. Interestingly, although changes in cartilage stiffness did not significantly influence ET opening under low adhesion conditions, ET opening was highly sensitive to changes in cartilage stiffness under high adhesion conditions. Therefore, our multi‐scale computational models indicate that changes in mucosal adhesion as would occur during inflammatory OM alter the biomechanical mechanisms of ET function. Copyright © 2016 John Wiley & Sons, Ltd.
BODIPY‐Based Nanomicelles as Near‐Infrared Fluorescent “Turn‐On” Sensors for Biogenic Thiols
Authors: Huang Ling , Duan Ran , Li Zhanjun , Zhang Yuanwei , Zhao Jianzhang , Han Gang
Published: February 2016

We report novel, aqueous, soluble, distyryl boron dipyrromethene (BODIPY)‐containing nanomicelles as biogenic thiol sensors with near‐infrared (NIR) “turn‐on” properties. The average hydrodynamic diameter of these nanomicelles is 30 nm. They show good photostability, are selective towards biogenic thiols, and function within a broad pH window (pH 3–10). Near‐infrared‐emitting distyryl‐BODIPY was chemically linked to fluorescence quencher group of 2,4‐dinitrobenzenesulfonyl (DNBS) and was then water solubilized and formed into nanomicelles via polylactic acid‐polyethylene glycol (PLA‐PEG) encapsulation. When thiols react with the DNBS moiety, we observe subsequent recovery of distyryl‐BODIPY fluorescence both in vitro and in living cells. This work provides a simple and general method to construct intracellular nanoprobes for biogenic thiols and may pave the way to the development other fluorescence‐dye‐based sensors.
Nanostructuration Effect on the Thermal Behavior of Ionic Liquids
Authors: Rodrigues Ana S. M. C. , Santos Luís M. N. B. F.
Published: February 2016

This work shows how the nanostructuration of ionic liquids (ILs) governs the glass and melting transitions of the bistriflimide imidazolium‐based [CnC1im][NTf2] and [CnCnim][NTf2] series, which highlights the trend shift that occurs at the critical alkyl size (CAS) of n=6. An initial increase in the glass temperature (Tg) with an increase in the alkyl side chain was observed due to the intensification of the dispersive interactions (van der Waals). Above the CAS, the −CH2− increment has the same effect in both glass and liquid states, which leads to a plateau in the glass transition after nanostructuration. The melting temperature (Tm) of the [CnC1im][NTf2] and [CnCnim][NTf2] series presents a V‐shaped profile. For the short‐alkyl ILs, the −CH2− increment affects the electrostatic ion pair interactions, which leads to an increase in the conformational entropy. The −CH2− increment disturbs the packing ability of the ILs and leads to a higher entropy value (
) and consequently a decrease in Tm. Above the CAS, the −CH2− contribution to the melting temperature becomes more regular, as a consequence of the nanostructuration of the IL into polar and nonpolar domains. The dependence of the alkyl chain on the temperature, enthalpy, and entropy of melting in the ILs above the CAS is very similar to the one observed for the alkane series, which highlights the importance of the nonpolar alkyl domains on the ILs thermal behavior.
Addressing the Requirements of High‐Sensitivity Single‐Molecule Imaging of Low‐Copy‐Number Proteins in Bacteria
Authors: Tuson Hannah H. , Aliaj Alisa , Brandes Eileen R. , Simmons Lyle A. , Biteen Julie S.
Published: February 2016

Single‐molecule fluorescence super‐resolution imaging and tracking provide nanometer‐scale information about subcellular protein positions and dynamics. These single‐molecule imaging experiments can be very powerful, but they are best suited to high‐copy number proteins where many measurements can be made sequentially in each cell. We describe artifacts associated with the challenge of imaging a protein expressed in only a few copies per cell. We image live Bacillus subtilis in a fluorescence microscope, and demonstrate that under standard single‐molecule imaging conditions, unlabeled B. subtilis cells display punctate red fluorescent spots indistinguishable from the few PAmCherry fluorescent protein single molecules under investigation. All Bacillus species investigated were strongly affected by this artifact, whereas we did not find a significant number of these background sources in two other species we investigated, Enterococcus faecalis and Escherichia coli. With single‐molecule resolution, we characterize the number, spatial distribution, and intensities of these impurity spots.
Using (FH)2and (FH)3to Bridge the σ‐Hole and the Lone Pair at P in Complexes with H2XP, for X=CH3, OH, H, CCH, F, Cl, NC, and CN
Authors: Del Bene Janet E. , Alkorta Ibon , Elguero José
Published: February 2016

Ab initio MP2/aug′‐cc‐pVTZ calculations are used to investigate the binary complexes H2XP:HF, the ternary complexes H2XP:(FH)2, and the quaternary complexes H2XP:(FH)3, for X=CH3, OH, H, CCH, F, Cl, NC, and CN. Hydrogen‐bonded (HB) binary complexes are formed between all H2XP molecules and FH, but only H2FP, H2ClP, and H2(NC)P form pnicogen‐bonded (ZB) complexes with FH. Ternary complexes with (FH)2are stabilized by F−H⋅⋅⋅P and F−H⋅⋅⋅F hydrogen bonds and F⋅⋅⋅P pnicogen bonds, except for H2(CH3)P:(FH)2and H3P:(FH)2, which do not have pnicogen bonds. All quaternary complexes H2XP:(FH)3are stabilized by both F−H⋅⋅⋅P and F−H⋅⋅⋅F hydrogen bonds and P⋅⋅⋅F pnicogen bonds. Thus, (FH)2with two exceptions, and (FH)3can bridge the σ‐hole and the lone pair at P in these complexes. The binding energies of H2XP:(FH)3complexes are significantly greater than the binding energies of H2XP:(FH)2complexes, and nonadditivities are synergistic in both series. Charge transfer occurs across all intermolecular bonds from the lone‐pair donor atom to an antibonding σ* orbital of the acceptor molecule, and stabilizes these complexes. Charge‐transfer energies across the pnicogen bond correlate with the intermolecular P−F distance, while charge‐transfer energies across F−H⋅⋅⋅P and F−H⋅⋅⋅F hydrogen bonds correlate with the distance between the lone‐pair donor atom and the hydrogen‐bonded H atom. In binary and quaternary complexes, charge transfer energies also correlate with the distance between the electron‐donor atom and the hydrogen‐bonded F atom. EOM‐CCSD spin‐spin coupling constants2hJ(F–P) across F−H⋅⋅⋅P hydrogen bonds, and1pJ(P–F) across pnicogen bonds in binary, ternary, and quaternary complexes exhibit strong correlations with the corresponding intermolecular distances. Hydrogen bonds are better transmitters of F–P coupling data than pnicogen bonds, despite the longer F⋅⋅⋅P distances in F−H⋅⋅⋅P hydrogen bonds compared to P⋅⋅⋅F pnicogen bonds. There is a correlation between the two bond coupling constants2hJ(F–F) in the quaternary complexes and the corresponding intermolecular distances, but not in the ternary complexes, a reflection of the distorted geometries of the bridging dimers in ternary complexes.
Obesity and post‐operative cognitive dysfunction: a systematic review and meta‐analysis
Authors: Feinkohl Insa , Winterer Georg , Pischon Tobias
Published: February 2016

Background

Post‐operative cognitive dysfunction, a condition distinct from post‐operative delirium (POD), occurs frequently after surgery, and is related to dementia and premature death. Obesity increases the risk of late‐life cognitive impairment, but little is known about its role in post‐operative cognitive dysfunction. We conducted a systematic review and meta‐analysis of studies on the association between obesity and risk of post‐operative cognitive dysfunction.

Methods

PubMed and the Cochrane Library were systematically searched. Studies were included if they had prospective designs, reported on human adults undergoing surgery, if cognitive function was measured pre‐ and post‐surgery, if obesity, body mass index (BMI) and/or body weight were ascertained, and if associations with post‐operative cognitive dysfunction were reported as relative risks or odds ratios. Underweight, weight loss, and post‐operative delirium were not considered.

Results

Inclusion criteria were met by six articles. Samples totaled 1432 older patients (mean age ≥62 years) who were followed up for 24 h to 12 months after surgery. Analysis of studies with obesity defined as a categorical measure found a non‐significantly higher risk of post‐operative cognitive dysfunction among persons with BMI > 30 kg/m2 versus ≤30 kg/m2 (relative risk 1.27; 95% confidence interval 0.95, 1.70; p = 0.10). No such associations were found for studies that analysed BMI or body weight continuously as predictors of post‐operative cognitive dysfunction (relative risk 0.98 per kg/m2; 95% confidence interval 0.93, 1.03, p = 0.45; relative risk 0.99 per kg; 95% confidence interval 0.89, 1.09; p = 0.83, respectively).

Conclusions

Few studies have addressed the topic, and the results of these studies provide only limited support for an increased risk of post‐operative cognitive dysfunction in patients who are obese. Further large‐scale, prospective investigations are necessary for clarification. Copyright © 2016 John Wiley & Sons, Ltd.
Mir‐217 promotes inflammation and fibrosis in high glucose cultured rat glomerular mesangial cells via Sirt1/HIF‐1α signaling pathway
Authors: Shao Ying , Lv Chuan , Wu Can , Zhou Yuehong , Wang Qiuyue
Published: February 2016

Background

Silent information regulator 1 (Sirt1) plays a protective role in kidney. Sirt1 suppresses activation of hypoxia‐inducible factor‐1 alpha (HIF‐1α), with MircroRNA‐217 (Mir‐217) being closely related to Sirt1. The relationship of Sirt1, HIF‐1α and Mir‐217, however, has never been reported in high glucose cultured rat glomerular mesangial cells (RMCs). Thus, we explored the role of Mir‐217 on inflammation and fibrosis in RMCs cultured with high glucose in vitro through Sirt1/HIF‐1α signaling pathway.

Methods

Rat glomerular mesangial cells were pre‐incubated with Sirt1 activator Resveratrol prior to high glucose treatment. Furthermore the cells were transiently transfected with Sirt1 small interfering RNA (siRNA), HIF‐1α siRNA and Mir‐217 inhibitor using Lipofectamine 2000. Real‐time PCR was used to analyse the expression of Mir‐217, Sirt1 mRNA and HIF‐1α mRNA; Western Blot was used to observe protein expression of Sirt1, HIF‐1α, connective tissue growth factor, endothelin‐1 and fibronectin; enzyme‐linked immunosorbent assay was used to detect protein expression of transforming growth factor‐β1 and vascular endothelial growth factor.

Results

High glucose increased Mir‐217 expression. High glucose decreased Sirt1 expression, accompanied by the increased HIF‐1α expression and then promoted inflammation and fibrosis. In addition, Mir‐217 gene silencing or Resveratrol could suppress the expression of HIF‐1α, which in turn restrained inflammation and fibrosis in rat glomerular mesangial cells cultured with high glucose.

Conclusion

This study clarified the role of Mir‐217 in high glucose cultured rat glomerular mesangial cells through Sirt1/HIF‐1α signaling pathway and provided new therapeutic targets for diabetic nephropathy. Copyright © 2016 John Wiley & Sons, Ltd.
Caffeine intake enhances the benefits of sodium glucose transporter 2 inhibitor
Authors: Hashimoto Yoshitaka , Tanaka Muhei , Yamazaki Masahiro , Nakano Koji , Ushigome Emi , Okada Hiroshi , Oda Yohei , Nakamura Naoto , Fukui Michiaki
Published: February 2016

Background

The effect of sodium glucose transporter 2 (SGLT‐2) inhibitors is dependent on the glomerular filtration rate. It has been reported that caffeine intake increases glomerular filtration rate. However, the effect of caffeine intake on urinary glucose excretion in patients who take SGLT‐2 inhibitors is unclear.

Methods

Six patients with type 2 diabetes took part in a randomized, open‐label, crossover pilot study. The patients took SGLT‐2 inhibitors (ipragliflozin) for 9 days. On day 3, 6 and 9, the patients were assigned to one of three studies: Water 500, patients drank 500 mL of water in 3 h; Water 1500, patients drank 1500 mL of water in 3 h; and Caffeine 500, patients drank 500 mL of water with 400 mg of caffeine in 3 h. In all of the studies, the patients' urine was collected over a 6‐h period. In addition, we enrolled 60 patients with type 2 diabetes who newly took SGLT‐2 inhibitors in a 3‐month follow‐up cohort study to investigate the effect of caffeine intake on glucose control. Caffeine intake was evaluated using questionnaires.

Results

The 6‐h median (interquartile range) urinary glucose excretion was 9.5 (8.5–9.7) g in Water 500, 12.2 (10.3–27.2) g in Water 1500 and 15.7 (11.4–21.4) g in Caffeine 500 (p = 0.005 vs Water 500). In the cohort study, multiple regression analysis demonstrated that log (caffeine intake) was associated with a change in HbA1c (β = −0.299, p = 0.043) after adjusting for covariates.

Conclusions

Caffeine intake enhanced the effect of SGLT‐2 inhibitors. Copyright © 2016 John Wiley & Sons, Ltd.
The relationship between three eGFR formulas and hospitalization for heart failure in 54 486 individuals with type 2 diabetes
Authors: Tancredi Mauro , Rosengren Annika , Olsson Marita , Gudbjörnsdottir Soffia , Svensson Ann‐Marie , Haraldsson B. , Lind Marcus
Published: February 2016

Objective

This study aims to study the association between renal function and hospitalization for heart failure (HF) in individuals with type 2 diabetes.

Methods

Renal function was determined according to three formulas used to estimate glomerular filtration rate (eGFR): Cockcroft–Gault, modified diet in renal disease (MDRD) and chronic kidney disease epidemiology (CKD‐EPI). Proportional hazards regression models adjusted for age, sex, HbA1c, blood pressure, smoking and cardiovascular comorbidities were constructed for each eGFR formula to estimate risk of hospitalization for heart failure. Systematic pairwise likelihood ratio tests of nested models were used to compare the predictive power of each eGFR formula.

Results

In 54 486 patients, evaluated over a median follow‐up of 7.0 years, a total of 5936 (10.9%) developed heart failure, with an excess risk in all eGFR categories below 60 mL/min/1.73 m2 (reference: eGFR >90 mL/min/1.73 m2). Hazard ratios ranged from 1.25 to 1.35 for eGFR 45–60 mL/min/1.73 m2, 1.62 to 1.66 for eGFR 30–45 mL/min/1.73 m2 and 2.18 to 2.52 for eGFR <30 mL/min/1.73 m2 in the three eGFR formulas. In pairwise comparisons, the model with the MDRD variable added significantly more information than the Cockcroft–Gault variable. For the model with the CKD‐EPI variable, no clear differences in predictive power for HF hospitalization existed in relation to the other eGFR formulas.

Conclusion

Patients with type 2 diabetes, with eGFR 45 to 60 mL/min/1.73 m2, have approximately 25–35% increased risk of hospitalization for HF, increasing with lower eGFR, to 2–2.5 times in those with eGFR <30 mL/min/1.73 m2. The MDRD formula for calculating eGFR is more predictive of hospitalization for heart failure than the Cockcroft–Gault formula. Copyright © 2016 John Wiley & Sons, Ltd.
Novel markers to detect recombinant human insulin‐like growth factor‐I (rhIGF‐I)/rhIGF binding protein‐3 (rhIGFBP‐3) misuse in athletes
Authors: Holt Richard I. G. , Guha Nishan , Böhning Walailuck , Bartlett Christiaan , Cowan David A. , Sönksen Peter H. , Böhning Dankmar
Published: February 2016

Insulin‐like growth factor‐I (IGF‐I) is abused by elite athletes for its metabolic and anabolic effects. We have previously shown that it is possible to detect IGF‐I misuse by measuring serum IGF‐I and procollagen type III amino‐terminal propeptide (P‐III‐NP) but a pilot study suggested measuring IGF‐II, IGF binding protein‐2 (IGFBP‐2) and acid‐labile subunit (ALS) may improve the detection of IGF‐I administration. The aim of the study was to assess this in a randomized controlled trial. Twenty‐six female and 30 male recreational athletes were randomized to 28 days’ treatment with placebo or recombinant human (rh)IGF‐I/rhIGF binding protein‐3 (IGFBP‐3) complex (30 mg/day or 60 mg/day), followed by 56 days’ washout. IGF‐II, IGFBP‐2 and ALS (women only) were measured using commercial immunoassays. IGFBP‐2 increased and IGF‐II decreased in response to both low and high dose rhIGF‐I/rhIGFBP‐3 in both women and men while ALS decreased in women in response to high dose rhIGF‐I/rhIGFBP‐3. Two days after discontinuing treatment, significant differences remained between the three treatment groups in IGFBP‐2 and IGF‐II, but not ALS. Thereafter there were no significant differences between the three treatment groups in any of the markers. Combining IGF‐I with IGF‐II and/or IGFBP‐2 improved the performance of the test to detect rhIGF‐I/rhIGFBP‐3 administration in both women and men. Copyright © 2016 John Wiley & Sons, Ltd.
In vitro metabolism of the synthetic cannabinoid 3,5‐AB‐CHMFUPPYCA and its 5,3‐regioisomer and investigation of their thermal stability
Authors: Franz Florian , Angerer Verena , Brandt Simon D. , McLaughlin Gavin , Kavanagh Pierce V. , Moosmann Bjoern , Auwärter Volker
Published: February 2016

Recently, the pyrazole‐containing synthetic cannabinoid N‐(1‐amino‐3‐methyl‐1‐oxobutan‐2‐yl)‐1‐(cyclohexylmethyl)‐3‐(4‐fluorophenyl)‐1H‐pyrazole‐5‐carboxamide (3,5‐AB‐CHMFUPPYCA) has been identified as a ‘research chemical’ both in powdered form and as an adulterant present in herbal preparations. Urine is the most common matrix used for abstinence control and the extensive metabolism of synthetic cannabinoids requires implementation of targeted analysis. The present study describes the investigation of the in vitro phase I metabolism of 3,5‐AB‐CHMFUPPYCA and its regioisomer 5,3‐AB‐CHMFUPPYCA using pooled human liver microsomes. Metabolic patterns of both AB‐CHMFUPPYCA isomers were qualitatively similar and dominated by oxidation of the cyclohexylmethyl side chain. Biotransformation to monohydroxylated metabolites of high abundance confirmed that these species might serve as suitable targets for urine analysis. Furthermore, since synthetic cannabinoids are commonly administered by smoking and because some metabolites can also be formed as thermolytic artefacts, the stability of both isomers was assessed under smoking conditions. Under these conditions, pyrolytic cleavage of the amide bond occurred that led to approximately 3 % conversion to heat‐induced degradation products that were also detected during metabolism. These artefactual ‘metabolites’ could potentially bias in vivo metabolic profiles after smoking and might have to be considered for interpretation of metabolite findings during hair analysis. This might be relevant to the analysis of hair samples where detection of metabolites is generally accepted as a strong indication of drug use rather than a potential external contamination. Copyright © 2016 John Wiley & Sons, Ltd.
Drug testing in Europe: monitoring results of the Trans European Drug Information (TEDI) project
Authors: Brunt Tibor M. , Nagy Constanze , Bücheli Alexander , Martins Daniel , Ugarte Miren , Beduwe Cécile , Ventura Vilamala Mireia
Published: February 2016

Drug testing is a harm reduction strategy that has been adopted by certain countries in Europe. Drug users are able to hand in their drugs voluntarily for chemical analysis of composition and dose. Drug users will be alerted about dangerous test results by the drug testing systems directly and through warning campaigns. An international collaborative effort was launched to combine data of drug testing systems, called the Trans European Drug Information (TEDI) project. Drug testing systems of Spain, Switzerland, Belgium, Austria, Portugal, and the Netherlands participated in this project. This study presents results of some of the main illicit drugs encountered: cocaine, ecstasy and amphetamine and also comments on new psychoactive substances (NPS) detected between 2008 and 2013. A total of 45 859 different drug samples were analyzed by TEDI. The drug markets of the distinct European areas showed similarities, but also some interesting differences. For instance, purity of cocaine and amphetamine powders was generally low in Austria, whilst high in Spain and the Netherlands. And the market for ecstasy showed a contrast: whereas in the Netherlands and Switzerland there was predominantly a market for ecstasy tablets, in Portugal and Spain MDMA (3,4‐methylenedioxymethamphetamine) crystals were much more prevalent. Also, some NPS appearing in ecstasy seemed more specific for one country than another. In general, prevalence of NPS clearly increased between 2008 and 2013. Drug testing can be used to generate a global picture of drug markets and provides information about the pharmacological contents of drugs for the population at risk. Copyright © 2016 John Wiley & Sons, Ltd.
Trophic overlap between fish and riparian spiders: potential impacts of an invasive fish on terrestrial consumers
Authors: Jackson Michelle C. , Woodford Darragh J. , Bellingan Terence A. , Weyl Olaf L. F. , Potgieter Michael J. , Rivers‐Moore Nick A. , Ellender Bruce R. , Fourie Hermina E. , Chimimba Christian T.
Published: February 2016

Studies on resource sharing and partitioning generally consider species that occur in the same habitat. However, subsidies between linked habitats, such as streams and riparian zones, create potential for competition between populations which never directly interact. Evidence suggests that the abundance of riparian consumers declines after fish invasion and a subsequent increase in resource sharing of emerging insects. However, diet overlap has not been investigated. Here, we examine the trophic niche of native fish, invasive fish, and native spiders in South Africa using stable isotope analysis. We compared spider abundance and diet at upstream fishless and downstream fish sites and quantified niche overlap with invasive and native fish. Spider abundance was consistently higher at upstream fishless sites compared with paired downstream fish sites, suggesting that the fish reduced aquatic resource availability to riparian consumers. Spiders incorporated more aquatic than terrestrial insects in their diet, with aquatic insects accounting for 45–90% of spider mass. In three of four invaded trout rivers, we found that the average proportion of aquatic resources in web‐building spider diet was higher at fishless sites compared to fish sites. The probability of web‐building and ground spiders overlapping into the trophic niche of invasive brown and rainbow trout was as high as 26 and 51%, respectively. In contrast, the probability of spiders overlapping into the trophic niche of native fish was always less than 5%. Our results suggest that spiders share resources with invasive fish. In contrast, spiders had a low probability of trophic overlap with native fish indicating that the traits of invaders may be important in determining their influence on ecosystem subsidies. We have added to the growing body of evidence that invaders can have cross‐ecosystem impacts and demonstrated that this can be due to niche overlap.
Optimization of Switching Phase of a Single‐Phase PWM dc–ac Inverter
Authors: MORITA KAZUYA , SHINDO TAKUYA , KURIHARA TAKUYA , JIN'NO KENYA
Published: February 2016

The purpose of this paper is to improve the efficiency of the single‐phase pulse width modulation (PWM) dc–ac inverter based on optimization of the switching phase of the PWM. Improvement of the efficiency means improvement of the quality of the output waveform and the conversion efficiency, and reduction of the switching loss. We propose an evaluation method involving minimization of the evaluation function by using the particle swarm optimization algorithm. We improve efficiency by setting a criterion for each index. As a result, the proposed algorithm can reduce high harmonic components in switching times shorter than the conventional triangle wave comparison method. Also, we confirm that the algorithm can improve the quality of the output waveform and the efficiency of conversion.
Innate lymphoid cells in asthma: Will they take your breath away?
Authors: Kim Hye Young , Umetsu Dale T. , Dekruyff Rosemarie H.
Published: February 2016

Asthma is a complex and heterogeneous disease that is characterized by airway hyper‐reactivity (AHR) and airway inflammation. Although asthma was long thought to be driven by allergen‐reactive TH2 cells, it has recently become clear that the pathogenesis of asthma is more complicated and associated with multiple pathways and cell types. A very exciting recent development was the discovery of innate lymphoid cells (ILCs) as key players in the pathogenesis of asthma. ILCs do not express antigen receptors but react promptly to “danger signals” from inflamed tissue and produce an array of cytokines that direct the ensuing immune response. The roles of ILCs may differ in distinct asthma phenotypes. ILC2s may be critical for initiation of adaptive immune responses in inhaled allergen‐driven AHR, but may also function independently of adaptive immunity, mediating influenza‐induced AHR. ILC2s also contribute to resolution of lung inflammation through their production of amphiregulin. Obesity‐induced asthma is associated with expansion of IL‐17A‐producing ILC3s in the lungs. Furthermore, ILCs may also contribute to steroid‐resistant asthma. Although the precise roles of ILCs in different types of asthma are still under investigation, it is clear that inhibition of ILC function represents a potential target that could provide novel treatments for asthma.
Follicular regulatory T cells repress cytokine production by follicular helper T cells and optimize IgG responses in mice
Authors: Wu Hao , Chen Yuxin , Liu Hong , Xu Lin‐Lin , Teuscher Paula , Wang Shixia , Lu Shan , Dent Alexander L.
Published: February 2016

Follicular helper T (Tfh) cells provide crucial help to germinal center B (GCB) cells for proper antibody production, and a specialized subset of regulatory T cells, follicular regulatory T (Tfr) cells, modulate this process. However, Tfr‐cell function in the GC is not well understood. Here, we define Tfr cells as a CD4+ Foxp3+ CXCR5hi PD‐1hi CD25low TIGIThigh T‐cell population. Furthermore, we have used a novel mouse model (“Bcl6FC”) to delete the Bcl6 gene in Foxp3+ T cells and thus specifically deplete Tfr cells. Following immunization, Bcl6FC mice develop normal Tfh‐ and GCB‐cell populations. However, Bcl6FC mice produce altered antigen‐specific antibody responses, with reduced titers of IgG and significantly increased IgA. Bcl6FC mice also developed IgG antibodies with significantly decreased avidity to antigen in an HIV‐1 gp120 “prime‐boost” vaccine model. In an autoimmune lupus model, we observed strongly elevated anti‐DNA IgA titers in Bcl6FC mice. Additionally, Tfh cells from Bcl6FC mice consistently produce higher levels of Interferon‐γ, IL‐10 and IL‐21. Loss of Tfr cells therefore leads to highly abnormal Tfh‐cell and GCB‐cell responses. Overall, our study has uncovered unique regulatory roles for Tfr cells in the GC response.
Multicomponent and Multicatalytic Reactions – A Synthetic Strategy Inspired by Nature
Authors: Galván Alicia , Fañanás Francisco J. , Rodríguez Félix
Published: February 2016

The dream of chemists to imitate the efficiency of Nature for the construction of complex molecules from simple starting materials has driven the development of new concepts in the area of catalysis. In this context, “Multicomponent and Multicatalytic Reactions” have emerged as a highly valuable synthetic tool. These reactions try to mimic the way the enzymatic machinery transforms a series of starting materials into intricate structures. This microreview shows some relevant multicomponent and multicatalytic reactions with the intention of demonstrating the incredible potential of this type of processes. The content is organized according to the type of multicatalytic system used (metal/metal, metal/organic, or organic/organic).