bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling study of silica membrane performance for hydrogen separation
Authors: Aghaeinejad‐Meybodi Abbas , Ghasemzadeh Kamran , Babaluo Ali Akbar , Morrone Pietropaolo , Basile Angelo
Published: July 2015

The main aim of this work is the presentation of quantitative analysis of silica membrane for hydrogen separation from methanol steam reforming products to produce high purity hydrogen. This study uses a single stage silica membrane in three different flow patterns, namely cocurrent, countercurrent and cross flow, for separation of a typical methanol steam reforming products stream. The modeling results showed that the silica membrane presents noticeable performance to produce high purity hydrogen. In particular, by considering the stage cut, it was found that the hydrogen molar fraction in the permeate side was decreased by increasing the stage cut from 0.1 to 0.65, whereas the carbon monoxide molar fraction increased for all of the flow patterns. In addition, a similar effect was observed for membrane surface area. Moreover, the retentate side pressure effect was positive on the silica membrane performance, although the improvement of silica membrane performance was not considerable for more than a pressure gradient of 3 bar. This analysis indicated that by using single stage silica membrane, 99% hydrogen molar fraction and 0.4% carbon monoxide molar fraction in the permeate side can be achieved for a pressure gradient equal to 3 bar. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.
Fabrication of a novel cellulose acetate imprinted membrane assisted with chitosan‐wrapped multi‐walled carbon nanotubes for selective separation of salicylic acid from industrial wastewater
Authors: Meng Minjia , He Zhihui , Yan Li , Yan Yongsheng , Sun Fengquan , Liu Yan , Liu Shijuan
Published: July 2015

Highly selective cellulose acetate (CA) blend imprinted membranes for salicylic acid (SA) removal were synthesized by phase inversion technique with chitosan as a functional polymer and chitosan‐wrapped multi‐walled carbon nanotubes (CHI‐wrapped MWCNTs) as the additives. The surface and cross‐sectional morphology of membranes were strongly affected by the amount of CHI‐wrapped MWCNTs. As compared to M1‐MIM, M2‐MIM, and M4‐MIM, the M3‐MIM with 2.0 wt % CHI‐wrapped MWCNTs showed higher membrane flux, faster kinetic, binding capacity and better selectivity for SA. The experimental data of adsorption kinetic were well fitted to the pseudo‐second‐order kinetic model by multiple regression analysis. The M3‐MIM had the maximum adsorption capacity for SA. The selectivity coefficients of SA to p‐hydroxybenzoic acid (p‐HB) and acetylsalicylic acid (ASA) over M3‐MIM were 6.3090 and 6.0019, respectively, showing that M3‐MIM had excellent binding affinity and selectivity for separation of SA from SA‐contained aqueous solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42654.
Microstructure and multifunctional properties of liquid + polymer bicomponent structural electrolytes: Epoxy gels and porous monoliths
Authors: Gienger Edwin B. , Nguyen Phuong‐Anh T. , Chin Wai , Behler Kristopher D. , Snyder James F. , Wetzel Eric D.
Published: July 2015

Multifunctional structural batteries and supercapacitors have the potential to improve performance and efficiency in advanced lightweight systems. A critical requirement is a structural electrolyte with superior multifunctional performance. We present here structural electrolytes prepared by the integration of liquid electrolytes with structural epoxy networks. Two distinct approaches were investigated: direct blending of an epoxy resin with a poly(ethylene‐glycol) (PEG)‐ or propylene carbonate (PC)‐based liquid electrolyte followed by in‐situ cure of the resin; and formation of a porous neat epoxy sample followed by backfill with a PC‐based electrolyte. The results show that in situ cure of the electrolytes within the epoxy network does not lead to good multifunctional performance due to a combination of plasticization of the structural network and limited percolation of the liquid network. In contrast, addition of a liquid electrolyte to a porous monolith results in both good stiffness and high ionic conductivity that approach multifunctional goals. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42681.
Epoxy/montmorillonite nanocomposites for improving aircraft radome longevity
Authors: García Carla , Fittipaldi Mauro , Grace Landon R.
Published: July 2015

The potential of nanoclay reinforcement to improve radome performance and longevity is quantified via a resonant technique. Epoxies used for radome applications are susceptible to environmental degradation through moisture absorption. Moisture in composite systems can degrade mechanical and dielectric properties, which is of particular concern in radome applications where low dielectric properties are crucial for maintaining radar transparency. The addition of nanoclay may prove a viable method for dielectric and structural performance improvement through moisture absorption minimization. The dielectric properties of an epoxy/montmorillonite nanocomposite are evaluated as a function of nanoclay weight percentage and moisture content using a split‐post dielectric resonator operating at 10 GHz. An increase of 25% in relative permittivity and 480% in loss tangent is observed for nanocomposites contaminated with 8.4% water by weight in the most extreme case. The addition of 2% nanoclay by weight effectively delayed a 16% degradation in relative permittivity by 760 hours. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42691.
Characterization of recycled styrene butadiene rubber ground tire rubber: Combining X‐ray fluorescence, differential scanning calorimetry, and dynamical thermal analysis for quality control
Authors: Liang Huan , Rodrigue Denis , Brisson Josée
Published: July 2015

Appraisal of the main rubber characterization techniques for styrene butadiene rubber (SBR) was performed on standard SBR samples as well as recycled ground tire rubber (GTR) from an industrial tire recycling facility, containing a blend of SBR and natural rubber. The aim of the work was to provide additional information relevant to quality control in the field of rubber recycling. Benchmark characterization of industrial samples by inductively coupled plasma optical emission spectrometry, atomic absorption spectrometry, solid‐state proton nuclear magnetic resonance, and elemental (CHNS) analysis are reported. X‐ray fluorescence spectrometry is shown to be rapid and quantitative for determining the zinc content in an industrial context. Thermogravimetric analysis, already used to determine carbon black and inorganic material content in rubbers and GTR, is recommended for determination of monomer weight ratios of SBR sources not containing other rubbers, but not for GTR. Differential scanning calorimetry (DSC) measurements of the glass‐transition show that changes in monomer ratio affect glass‐transition temperature values, and therefore, DSC can be used to detect changes in rubber composition from batch to batch. These results show that DSC and X‐ray fluorescence spectroscopy characterization techniques can be used for GTR and may lead to more thorough and rapid quality control procedures of these complex samples. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42692.
Preparation of zinc‐oxide‐free natural rubber nanocomposites using nanostructured magnesium oxide as cure activator
Authors: Roy Kumarjyoti , Alam Md. Najib , Mandal Swapan Kumar , Debnath Subhas Chandra
Published: July 2015

The effect of sol–gel synthesized magnesium oxide (MgO) nanoparticles as cure activator is studied for the first time in the vulcanization of natural rubber (NR) and compared with conventional zinc oxide (ZnO) in terms of cure, mechanical, and thermal properties. The NR vulcanizate with 1 phr (Parts per hundred parts of rubber) nano MgO shows an excellent improvement in the curing characteristics and the value of cure rate index is about 400% greater for NR vulcanizate containing 1 phr nano MgO in comparison to the NR vulcanizate with 5 phr conventional ZnO. Both mechanical and thermal properties of NR vulcanizate are found to be satisfactory in the presence of 1 phr nano MgO as cure activator in comparison to conventional NR vulcanizate. This study shows that only 1 phr nano MgO can successfully replace 5 phr conventional ZnO with better resulting properties in the sulfur vulcanization of NR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42705.
Gene‐Based Meta‐Analysis of Genome‐Wide Association Study Data Identifies Independent Single‐Nucleotide Polymorphisms in ANXA6 as Being Associated With Systemic Lupus Erythematosus in Asian Populations
Authors: Zhang Jing , Zhang Lu , Zhang Yan , Yang Jing , Guo Mengbiao , Sun Liangdan , Pan Hai‐Feng , Hirankarn Nattiya , Ying Dingge , Zeng Shuai , Lee Tsz Leung , Lau Chak Sing , Chan Tak Mao , Leung Alexander Moon Ho , Mok Chi Chiu , Wong Sik Nin , Lee Ka Wing , Ho Marco Hok Kung , Lee Pamela Pui Wah , Chung Brian Hon‐Yin , Chong Chun Yin , Wong Raymond Woon Sing , Mok Mo Yin , Wong Wilfred Hing Sang , Tong Kwok Lung , Tse Niko Kei Chiu , Li Xiang‐Pei , Avihingsanon Yingyos , Rianthavorn Pornpimol , Deekajorndej Thavatchai , Suphapeetiporn Kanya , Shotelersuk Vorasuk , Ying Shirley King Yee , Fung Samuel Ka Shun , Lai Wai Ming , Garcia‐Barceló Maria‐Mercè , Cherny Stacey S. , Sham Pak Chung , Cui Yong , Yang Sen , Ye Dong Qing , Zhang Xue‐Jun , Lau Yu Lung , Yang Wanling
Published: July 2015

Objective

Previous genome‐wide association studies (GWAS), which were mainly based on single‐variant analysis, have identified many systemic lupus erythematosus (SLE) susceptibility loci. However, the genetic architecture of this complex disease is far from being understood. The aim of this study was to investigate whether using a gene‐based analysis may help to identify novel loci, by considering global evidence of association from a gene or a genomic region rather than focusing on evidence for individual variants.

Methods

Based on the results of a meta‐analysis of 2 GWAS of SLE conducted in 2 Asian cohorts, we performed an in‐depth gene‐based analysis followed by replication in a total of 4,626 patients and 7,466 control subjects of Asian ancestry. Differential allelic expression was measured by pyrosequencing.

Results

More than one‐half of the reported SLE susceptibility loci showed evidence of independent effects, and this finding is important for understanding the mechanisms of association and explaining disease heritability. ANXA6 was detected as a novel SLE susceptibility gene, with several single‐nucleotide polymorphisms (SNPs) contributing independently to the association with disease. The risk allele of rs11960458 correlated significantly with increased expression of ANXA6 in peripheral blood mononuclear cells from heterozygous healthy control subjects. Several other associated SNPs may also regulate ANXA6 expression, according to data obtained from public databases. Higher expression of ANXA6 in patients with SLE was also reported previously.

Conclusion

Our study demonstrated the merit of using gene‐based analysis to identify novel susceptibility loci, especially those with independent effects, and also demonstrated the widespread presence of loci with independent effects in SLE susceptibility genes.
Engineering of alanine dehydrogenase from Bacillus subtilis for novel cofactor specificity
Authors: Lerchner Alexandra , Jarasch Alexander , Skerra Arne
Published: July 2015

The l‐alanine dehydrogenase of Bacillus subtilis (BasAlaDH), which is strictly dependent on NADH as redox cofactor, efficiently catalyzes the reductive amination of pyruvate to l‐alanine using ammonia as amino group donor. To enable application of BasAlaDH as regenerating enzyme in coupled reactions with NADPH‐dependent alcohol dehydrogenases, we alterated its cofactor specificity from NADH to NADPH via protein engineering. By introducing two amino acid exchanges, D196A and L197R, high catalytic efficiency for NADPH was achieved, with kcat/KM = 54.1 µM−1 Min−1 (KM = 32 ± 3 µM; kcat = 1,730 ± 39 Min−1), almost the same as the wild‐type enzyme for NADH (kcat/KM = 59.9 µM−1 Min−1; KM = 14 ± 2 µM; kcat = 838 ± 21 Min−1). Conversely, recognition of NADH was much diminished in the mutated enzyme (kcat/KM = 3 µM−1 Min−1). BasAlaDH(D196A/L197R) was applied in a coupled oxidation/transamination reaction of the chiral dicyclic dialcohol isosorbide to its diamines, catalyzed by Ralstonia sp. alcohol dehydrogenase and Paracoccus denitrificans ω‐aminotransferase, thus allowing recycling of the two cosubstrates NADP+ and l‐Ala. An excellent cofactor regeneration with recycling factors of 33 for NADP+ and 13 for l‐Ala was observed with the engineered BasAlaDH in a small‐scale biocatalysis experiment. This opens a biocatalytic route to novel building blocks for industrial high‐performance polymers.
Polyacrylamide‐based semi‐interpenetrating networks for entrapment of laccase and their use in azo dye decolorization
Authors: Koklukaya Selva Zeynep , Sezer Serdar , Aksoy Serpil , Hasirci Nesrin
Published: July 2015

In this study, laccase from Trametes versicolor was immobilized in poly(acrylamide‐crotonic acid)/sodium alginate [P(AAm‐CrA)/alginate], poly(acrylamide‐crotonic acid)/K‐carrageenan [(P(AAm‐CrA)/K‐car)], poly(acrylamide‐citraconic acid)/sodium alginate (P(AAm‐CA)/alginate), and poly(acrylamide‐citraconic acid)/K‐carrageenan (P(AAm‐CA)/K‐car) semi‐interpenetrating network by entrapment method. Optimum pH and temperatures values were determined between 5.0–6.0 and 40–50 °C for free laccase (FL) and immobilized laccases, respectively. After 42 days of storage at 4 °C, FL and immobilized laccases retained their original activities in the range of 55%–73%. Percent decolorization of Acid Orange 52 by free enyzme and enyzmes immobilized in hydrogels was found between 63% and 39%. Percent decolorization of Acid Orange 52 in the presence of mediator by free enyzme was found 73% and enyzmes immobilized in hydrogels were found as 73%.
Butanol production by a Clostridium beijerinckii mutant with high ferulic acid tolerance
Authors: Liu Jun , Guo Ting , Wang Dong , Xu Jiahui , Ying Hanjie
Published: July 2015

A mutant strain of Clostridium beijerinckii, with high tolerance to ferulic acid, was generated using atmospheric pressure glow discharge and high‐throughput screening of C. beijerinckii NCIMB 8052. The mutant strain M11 produced 7.24 g/L of butanol when grown in P2 medium containing 30 g/L of glucose and 0.5 g/L of ferulic acid, which is comparable to the production from non‐ferulic acid cultures (8.11 g/L of butanol). When 0.8 g/L of ferulic acid was introduced into the P2 medium, C. beijerinckii M11 grew well and produced 4.91 g/L of butanol. Both cell growth and butanol production of C. beijerinckii M11 were seriously inhibited when 0.9 g/L of ferulic acid was added into the P2 medium. Furthermore, C. beijerinckii M11 could produce 6.13 g/L of butanol using non‐detoxified hemicellulosic hydrolysate from diluted sulfuric acid‐treated corn fiber (SAHHC) as the carbon source. These results demonstrate that C. beijerinckii M11 has a high ferulic acid tolerance and is able to use non‐detoxified SAHHC for butanol production.
Structural elucidation of gemifloxacin mesylate degradation product
Authors: Paim Clésio Soldateli , Führ Fernanda , Martins Magda Targa , Gnoatto Simone , Bajerski Lisiane , Garcia Cássia Virginia , Steppe Martin , Schapoval Elfrides Eva Scherman
Published: July 2015

Gemifloxacin mesylate (GFM), chemically (R,S)‐7‐[(4Z)‐3‐(aminomethyl)‐4‐(methoxyimino)‐1‐pyrrolidinyl]‐1‐cyclopropyl‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acid methanesulfonate, is a synthetic broad‐spectrum antibacterial agent. Although many papers have been published in the literature describing the stability of fluorquinolones, little is known about the degradation products of GFM. Forced degradation studies of GFM were performed using radiation (UV‐A), acid (1 mol L−1 HCl) and alkaline conditions (0.2 mol L−1 NaOH). The main degradation product, formed under alkaline conditions, was isolated using semi‐preparative LC and structurally elucidated by nuclear magnetic resonance (proton – 1H; carbon – 13C; correlate spectroscopy – COSY; heteronuclear single quantum coherence – HSQC; heteronuclear multiple‐bond correlation – HMBC; spectroscopy – infrared, atomic emission and mass spectrometry techniques). The degradation product isolated was characterized as sodium 7‐amino‐1‐pyrrolidinyl‐1‐cyclopropyl‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylate, which was formed by loss of the 3‐(aminomethyl)‐4‐(methoxyimino)‐1‐pyrrolidinyl ring and formation of the sodium carboxylate. The structural characterization of the degradation product was very important to understand the degradation mechanism of the GFM under alkaline conditions. In addition, the results highlight the importance of appropriate protection against hydrolysis and UV radiation during the drug‐development process, storage, handling and quality control. Copyright © 2015 John Wiley & Sons, Ltd.
Life satisfaction and status among adolescent law offenders
Authors: Buunk Abraham P. , Peiró José María , Rocabert Esperanza , Dijkstra Pieternel
Published: July 2015

Background

Life satisfaction among young offenders may be affected by the subjective experience of their social status and by the feeling of being a ‘loser’ compared with others, but it is not clear what variables affect such experiences in this group.

Aims

To examine relationships of type of sentence (prison or probation) and of gender with subjective social status, sense of defeat and life satisfaction among young offenders.

Methods

One hundred and five participants were randomly selected from a cohort of young offenders, stratifying for sentence type and for gender. They were interviewed by trained and experienced interviewers.

Results

Young people in a correctional facility experienced lower life satisfaction and greater sense of defeat than those on probation. Independently of judicial measure, low life satisfaction was correlated with sense of defeat among young men but not young women, whereas among young women, but not young men, low life satisfaction was associated with low subjective status.

Conclusions and implications

Our findings of a correlation between sentence type and life satisfaction needs new, longitudinal research to determine the direction of this relationship. Whether low life satisfaction is predictive of a custodial disposal for young offenders or such a sentence lowers life satisfaction, those trying to supervise or help these young people may need to take account of it. Further, our findings suggest that young male and young female offenders should perhaps be treated in different ways to improve their sense of satisfaction with life, which may, in turn, reduce their risk of reoffending. Copyright © 2015 John Wiley & Sons, Ltd.
Carbon‐Based Nanostructures for Advanced Catalysis
Authors: Zhai Yanling , Zhu Zhijun , Dong Shaojun
Published: July 2015

The development of state‐of‐the‐art catalysts plays a crucial role in the fields of materials science and engineering for efficient energy conversion and storage. Although some excellent catalysts have been developed, considerable challenges remain to bring down the cost and increase the activity of catalysts. The emergence of carbon materials (i.e., activated carbon, graphite, fullerenes, carbon nanotubes, diamond, graphene, etc.) provides an excellent alternative to traditional catalysts. Considerable effort has been made to develop diverse carbon‐based catalysts, including carbon in itself, heteroatom‐doped carbon, carbon supported catalysts, carbon hybrids, and so on. Additionally, tremendous progress has been achieved in various catalysis fields, such as chemical synthesis, gas or oil desulfurization, biosensor, energy storage and conversion, organism photodegradation, etc. This article reviews the versatility of carbon family, and their endless catalytic properties and applications, from the viewpoint of materials and chemistry.
Impact of Different Parameters for Pulsed‐Laser Welding of the Austenitic Stainless Steel 304
Authors: Gietzelt Thomas , Wunsch Torsten , Eichhorn Lutz , Dittmeyer Roland
Published: July 2015

For welding of delicate apparatuses made of thin sheet material, the distortion is strongly governed by the heat input. Parameter variations for pulsed‐laser welding were performed to study the influence of the energy input per unit length and per time as well as the impact of the pulse width and other parameters on the weld seam geometry. Even for a constant energy input per unit length, deviations of the cross section of the weld seam were observed due to different dissipation of the deposited energy. For the same energy input per unit length the geometry of the weld seam is strongly influenced by the pulse width. Also deviations from expected behavior were found and could be explained, e.g., by a shortfall in energy density to melt the material.
Surface Activation of Pt Nanoparticles Synthesised by “Hot Injection” in the Presence of Oleylamine
Authors: Humphrey Jo J. L. , Sadasivan Sajanikumari , Plana Daniela , Celorrio Verónica , Tooze Robert A. , Fermín David J.
Published: July 2015

Oleylamine (OA) based “hot injection” colloidal synthesis offers a versatile approach to the synthesis of highly monodisperse metallic and multi‐metallic alloyed nanostructures in the absence of potentially toxic and unstable phosphine compounds. For application in heterogeneous catalysis and electrocatalysis, the adsorbed OA species at the metal surfaces should be effectively removed without compromising the structure and composition of the nanostructures. Herein, we investigate the removal of OA from colloidal Pt nanoparticles through 1) “chemical methods” such as washing in acetic acid or ethanol, and ligand exchange with pyridine; and 2) thermal pre‐treatment between 185 and 400 °C in air, H2 or Ar atmospheres. The electrochemical reactivity of Pt nanoparticles is acutely affected by the presence of surface organic impurities, making this material ideal for monitoring the effectiveness of OA removal. The results showed that thermal treatment in Ar at temperatures above 400 °C provides highly active particles, with reactivity comparable to the benchmark commercial catalyst, Pt/ETEK. The mechanism involved in thermal desorption of OA was also investigated by thermogravimetric analysis coupled to mass spectrometry (TGA‐MS). Oxidation of HCOOH and adsorbed CO in acidic solution were used as test reactions to assess the Pt electrocatalytic activity.
Enantioselective Synthesis of Lepadins A–D from a Phenylglycinol‐Derived Hydroquinolone Lactam
Authors: Amat Mercedes , Pinto Alexandre , Griera Rosa , Bosch Joan
Published: July 2015

The marine alkaloids (−)‐lepadins A–C and (+)‐lepadin D, belonging to two diastereoisomeric series, were synthesized from an (R)‐phenylglycinol‐derived tricyclic lactam via a common cis‐decahydroquinoline intermediate. Crucial aspects of the synthesis are the stereochemical control in the assembly of the cis‐decahydroquinoline platform, in the introduction of the C2 methyl and C3 hydroxy substituents, and in the generation of the C5 stereocenter.
Enantioselective Pharmacokinetics of Doxazosin and Pharmacokinetic Interaction Between the Isomers in Rats
Authors: Li Qing , Kong Dezhi , Du Qian , Zhao Jing , Zhen Yaqin , Li Tonghui , Ren Leiming
Published: July 2015

In this study, the stereoselective pharmacokinetics of doxazosin enantiomers and their pharmacokinetic interaction were studied in rats. Enantiomer concentrations in plasma were measured using chiral high‐pressure liquid chromatography (HPLC) with fluorescence detection after oral or intravenous administration of (–)‐(R)‐doxazosin 3.0 mg/kg, (+)‐(S)‐doxazosin 3.0 mg/kg, and rac‐doxazosin 6.0 mg/kg. AUC values of (+)‐(S)‐doxazosin were always larger than those of (–)‐(R)‐doxazosin, regardless of oral or intravenous administration. The maximum plasma concentration (Cmax) value of (–)‐(R)‐doxazosin after oral administration was significantly higher when given alone (110.5 ± 46.4 ng/mL) versus in racemate (53.2 ± 19.7 ng/mL), whereas the Cmax value of (+)‐(S)‐doxazosin did not change significantly. The area under the curve (AUC) and Cmax values for (+)‐(S)‐doxazosin after intravenous administration were significantly lower, and its Cl value significantly higher, when given alone versus in racemate. We speculate that (–)‐(R)‐doxazosin increases (+)‐(S)‐doxazosin exposure probably by inhibiting the elimination of (+)‐(S)‐doxazosin, and the enantiomers may be competitively absorbed from the gastrointestinal tract. In conclusion, doxazosin pharmacokinetics are substantially stereospecific and enantiomer–enantiomer interaction occurs after rac‐administration. Chirality 27:738–744, 2015. © 2015 Wiley Periodicals, Inc.
Bromine Bonding Induced Selective Recognition of Different Guests for Hexaphenylbenzene Bromides in the Solid State
Authors: Peng Lianhui , Zhu Pengcheng , Meng Xianggao , Zhang Chun
Published: July 2015

With propeller‐like shape, hexaphenylbenzene bromides display different recognition abilities for guest molecules in solid state. HBH can encapsulate CH2Cl2 or Et2O molecules selectively from different solvent systems. For DBH, the recognition pattern is dominated between themselves. In CH2Cl2/toluene/Et2O system, toluene molecule can be encapsulated selectively by MBH. In these supramolecular assemblies, bromine bonding plays an important role.
Hydrodynamic Microgap Voltammetry under Couette Flow Conditions: Electrochemistry at a Rotating Drum in Viscous Poly(ethylene glycol)
Authors: Hotchen Christopher E. , Nguyen H. Viet , Fisher Adrian C. , Frith Paul E. , Marken Frank
Published: July 2015

Electrochemical processes in highly viscous media such as poly(ethylene glycol) (herein PEG200) are interesting for energy‐conversion applications, but problematic due to slow diffusion causing low current densities. Here, a hydrodynamic microgap experiment based on Couette flow is introduced for an inlaid disc electrode approaching a rotating drum. Steady‐state voltammetric currents are independent of viscosity and readily increased by two orders of magnitude with further potential to go to higher rotation rates and nanogaps. A quantitative theory is derived for the prediction of currents under high‐shear Couette flow conditions and generalised for different electrode shapes. The 1,1′‐ferrocene dimethanol redox probe in PEG200 (D=1.4×10−11 m2 s−1) is employed and data are compared with 1) a Levich‐type equation expressing the diffusion–convection‐limited current and 2) a COMSOL simulation model providing a potential‐dependent current trace.
Metal–Organic Frameworks via Emissive Metal‐Carboxylate Zwitterion Intermediates
Authors: Armaghan Mahsa , Shang Xiu‐Juan , Yuan Yan‐Qiu , Young David J. , Zhang Wen‐Hua , Hor T. S. Andy , Lang Jian‐Ping
Published: July 2015

This month’s cover is dedicated to the golden anniversary of Singapore by the collaborating groups of Wen‐Hua Zhang of the IMRE, Singapore, and T. S. Andy Hor of the NUS, Singapore, and two more groups from Monash University, Malaysia, and Soochow University, P. R. China. In the cover picture the number “50” commemorates the 50th anniversary of Singapore, the Lion City. The photo on the top‐right corner shows the modern skyline of Singapore. Underneath are the structures described in this article. Read the full text of the article at 10.1002/cplu.201500134.
Synchrotron radiation diffraction study of texture in α‐Fe2O3 powder induced by the magnetic field
Authors: Stȩkiel M. , Przeniosło R. , Duczmal M. , Wardecki D. , Buslaps T.
Published: July 2015

The interaction of the weak ferromagnetic moments of hematite, α‐Fe2O3, crystallites with the external dc magnetic field is studied by using synchrotron radiation powder diffraction. The observed angular distribution of the scattered intensities on the Debye‐Scherrer rings provide information about the reorientation of the crystallites. A quantitative model of the reorientation process is described. The proposed experimental method gives information which is complementary to powder diffraction, single crystal diffraction and magnetization studies. This method can be used to characterize the weak ferromagnetic states of novel multiferroic materials.
Controlled Silylation of Nanofibrillated Cellulose in Water: Reinforcement of a Model Polydimethylsiloxane Network
Authors: Zhang Zheng , Tingaut Philippe , Rentsch Daniel , Zimmermann Tanja , Sèbe Gilles
Published: July 2015

A comparative approach for the surface silylation of nanofibrillated cellulose (NFC) in water is proposed through an environmentally friendly sol–gel route based on alkoxysilanes. NFC suspensions were freeze‐dried under controlled conditions in the presence of methyltrimethoxysilane used as a model alkoxysilane. Two different protocols that involve different pH values (0.4 and 4) and post‐treatment procedures were investigated and compared. Protocol 1 led to a network of nanofibrils in which polysiloxane particles were dispersed, and protocol 2 produced a scaffold of cellulosic fibrils coated by a polysiloxane layer bonded firmly to the cellulosic substrate. Different from protocol 1, protocol 2 imparted the cellulosic material with hydrophobic properties and improved its thermal stability. Moreover, if 1 wt % of fibrils treated by protocol 2 were incorporated into a model polydimethylsiloxane network, substantial improvements of the static and dynamic mechanical properties of the composite were noted.
A weighted method for estimation of receptor occupancy for pharmacodynamic measurements in drug development
Authors: Sternebring Ola , Alifrangis Lene , Christensen Toke Folke , Ji Hong , Hegelund Anne Charlotte , Högerkorp Carl‐Magnus
Published: July 2015

Background

Flow cytometry‐based receptor occupancy (RO) assessments for pharmacodynamic (PD) response measurements along with drug pharmacokinetic (PK) measurements represent a cornerstone in mechanism based PK/PD modeling of drugs against cell surface targets. This report describes the utility of using a “Free” and a “Bound” assay in combination to derive RO estimations through a weighted calculation method.

Methods

Data from a RO assay validation study in human samples was used to explore the performance of various RO data calculation methods. The calculation methods were subsequently applied to investigate the best method to generate RO data in a first in human phase 1 clinical trial. Finally, the outcome of the analysis was used for PK/PD modeling of a prospective phase 2a trial.

Results

The validation data assessment demonstrated that a weighted RO calculation method had a better performance in terms of precision, accuracy and dynamic range. In the phase 1 clinical trial data analysis the weighted method again demonstrated a better performance resulting in a more robust RO estimation, and subsequently also generating a more reliable PK/PD simulation for the phase 2a trial.

Conclusions

This report demonstrated the utility of using a combined “Free” and “Bound” RO assessment together with a weighted calculation method to better support mechanism‐based PK/PD modeling activities. © 2015 International Clinical Cytometry Society
Performance modeling of data transmission by using random linear network coding in DTNs
Authors: Qin Shuang , Feng Gang
Published: July 2015

In Delay Tolerant Networks (DTNs), mobile nodes exploit encounter chances to transmit data via the established opportunistic link between encounter nodes. The transmission capacity between two encounter nodes is constrained by the duration of opportunistic links. How to transmit data efficiently is one of the fundamental and most important issues in DTNs. Recently, Random Linear Network Coding (RLNC) is proposed as a promising approach to improve data transmission efficiency in DTNs. To facilitate the development of deployment of RLNC based routing protocols, it is imperative to quantify the performance gain brought by RLNC in a rigorous and systematic way. In this paper, we develop an analytical model to evaluate the data transmission performance of RLNC based epidemic routing in DTNs. In the model, we consider that multiple unicast communication sessions compete for limited \capacity. Numerical results validate the effectiveness of our analytical model and demonstrate the significant performance improvement for data transmission in DTNs brought by RLNC. Our work of this paper provides a general tool for performance evaluation and useful guidelines for designing RLNC based routing protocols in DTNs. Copyright © 2015 John Wiley & Sons, Ltd.
Positive selection drives adaptive diversification of the 4‐coumarate: CoA ligase (4CL) gene in angiosperms
Authors: Sun Haiyan , Guo Kai , Feng Shengqiu , Zou Weihua , Li Ying , Fan Chunfen , Peng Liangcai
Published: July 2015

Lignin and flavonoids play a vital role in the adaption of plants to a terrestrial environment. 4‐Coumarate: coenzyme A ligase (4CL) is a key enzyme of general phenylpropanoid metabolism which provides the precursors for both lignin and flavonoids biosynthesis. However, very little is known about how such essential enzymatic functions evolve and diversify. Here, we analyze 4CL sequence variation patterns in a phylogenetic framework to further identify the evolutionary forces that lead to functional divergence. The results reveal that lignin‐biosynthetic 4CLs are under positive selection. The majority of the positively selected sites are located in the substrate‐binding pocket and the catalytic center, indicating that nonsynonymous substitutions might contribute to the functional evolution of 4CLs for lignin biosynthesis. The evolution of 4CLs involved in flavonoid biosynthesis is constrained by purifying selection and maintains the ancestral role of the protein in response to biotic and abiotic factors. Overall, our results demonstrate that protein sequence evolution via positive selection is an important evolutionary force driving adaptive diversification in 4CL proteins in angiosperms. This diversification is associated with adaption to a terrestrial environment.
Structural, Magnetic, DFT, and Biological Studies of Mononuclear and Dinuclear CuII Complexes with Bidentate N‐Heteroaromatic Schiff Base Ligands
Authors: Todorović Tamara , Grubišić Sonja , Pregelj Matej , Jagodič Marko , Misirlić‐Denčić Sonja , Dulović Marija , Marković Ivanka , Klisurić Olivera , Malešević Aleksandar , Mitić Dragana , Anđelković Katarina , Filipović Nenad
Published: July 2015

Copper(II) complexes with the condensation derivative of methyl hydrazinoacetate and 2‐acetylpyridine were synthesized. The X‐ray crystal structures for both complexes revealed that they are polymerized isomers. A common feature of both complexes is the bidentate coordination of the ligand by one hydrazone and one pyridine nitrogen atom. In the monomeric complex, the copper(II) center is tetracoordinate, whereas dimerization through chlorido bridges results in a pentacoordinate arrangement about the metal ions in the dimer. The electronic and magnetic properties of both complexes are discussed on the basis of their X‐ray structures, electron paramagnetic resonance (EPR) spectroscopy studies, and superconducting quantum interference device (SQUID) magnetization measurements combined with DFT calculations. Magnetostructural comparisons with structurally similar copper(II) complexes are also provided, and a possible correlation has been established. The antitumor activities of the CuII complexes were investigated against six different cancer cell lines, and the results suggest that the antiglioma action of the dimeric species is based on oxidative‐stress‐mediated phosphatidylserine externalization and caspase activation, which indicate apoptosis.
T‐Shaped (Donor–π–)2Acceptor–π–Donor Push–Pull Systems Based on Indan‐1,3‐dione
Authors: Solanke Parmeshwar , Bureš Filip , Pytela Oldřich , Klikar Milan , Mikysek Tomáš , Mager Loic , Barsella Alberto , Růžičková Zdeňka
Published: July 2015

Sixteen model (donor–π–)2acceptor–π–donor [(D–π–)2A–π–D] molecules with an extraordinary T‐shaped arrangement were designed and synthesized. Indan‐1,3‐dione was employed as a central acceptor with electron donors linked at the C‐2, C‐4, and C‐7 positions. These push–pull molecules represent a first systematic modification of an indan‐1,3‐dione‐fused benzene ring. The structures and properties of all target molecules were investigated by X‐ray analysis, electrochemistry, UV/Vis absorption spectroscopy, differential scanning calorimetry, electric‐field‐induced second‐harmonic generation (EFISHG) studies, and DFT calculations. A thorough evaluation of all of the gathered data has been performed, and structure–property relationships were evaluated. Electron donors attached at the C‐2 position through π systems of various lengths affect the studied properties most significantly. The side donors at C‐4 and C‐7 can be described as auxiliary and do not dominate the observed properties. However, thiophene is a more efficient donor than N,N‐dimethylaniline in this respect. Hence, indan‐1,3‐dione bearing a piperidylthiophene donor connected through a propenylidene spacer at C‐2 completed with two side thiophen‐2‐ylethynyl branches at C‐4 and C‐7 showed the highest figure of merit among the studied properties.
Conformational Switching in Heterochiral α,β2,3‐Hybrid Peptides in Response to Solvent Polarity
Authors: Balamurugan Dhayalan , Muraleedharan Kannoth M.
Published: July 2015

The ability of α,β2,3‐hybrid peptides with a heterochiral backbone to exist in a helical, extended, or partially folded state depending on the solvation conditions employed was investigated. The preference was found to be directly dictated by Cα–Cβ torsions in the β‐residues.
Substrate Activation in the Catalytic Asymmetric Hydrogenation ofN‐Heteroarenes
Authors: Balakrishna Bugga , Núñez‐Rico José Luis , Vidal‐Ferran Anton
Published: July 2015

Different methods for transformingN‐heteroarenes into more reactive derivatives for catalytic asymmetric hydrogenation are highlighted. The first strategy consists of facilitating hydrogenation by the formation of positively charged derivatives of the heteroarene. Catalyst deactivation processes arising upon binding of the substrate to the metal center can thus be prevented and, additionally, hydrogenation of positively charged heteroarenes may also be more favored than that of their neutral analogues. The second strategy is based on introducing a ligating group onto the substrate to assist its coordination to the metal center and facilitate hydrogenation by chelation assistance. The last strategy involves breaking the aromaticity of the heteroarene by inducing a double‐bond migration process. This microreview summarizes advances made in the above strategies, which have allowed the development of highly enantioselective catalytic hydrogenation ofN‐heteroarenes for the production of fully or partially saturated chiral heterocycles.
Copper/Selectfluor‐System‐Catalyzed Dehydration–Oxidation of Tertiary Cyclo­alcohols: Access to β‐Substituted Cyclohex‐2‐enones, 4‐Arylcoumarins, and Bi­aryls
Authors: Ren Shaobo , Zhang Jian , Zhang Jiahui , Wang Heng , Zhang Wei , Liu Yunkui , Liu Miaochang
Published: July 2015

A route to β‐substituted cyclohex‐2‐enones, 4‐arylcoumarins, and biaryls has been developed. This approach involves a one‐pot Cu0/Selectfluor‐catalyzed dehydration–oxidation of tertiary cycloalcohols. Thus, by using 2 equiv. of Selectfluor at 25 °C, the dehydration–oxidation of tertiary cyclohexanols and oxabenzocyclohexanols gave β‐substituted cyclohex‐2‐enones and 4‐arylcoumarins, respectively; whereas the dehydration–oxidation of tertiary cyclohexanols gave biaryls as the final products by using 2.5 equiv. of Selectfluor at 80 °C.
Domino Prins Cyclization of Enynols: Stereoselective Synthesis of Bicyclic Vinyl Fluorides
Authors: Venkateswarlu Anipireddy , Kanakaraju Marumudi. , Kunwar Ajit C. , Rami Reddy Yellala V. , Reddy Basi V. S.
Published: July 2015

A fluoride‐induced termination of Prins cyclization has been observed using a tethered alkyne and stoichiometric amounts of AgSbF6 and found to generate a novel series of 6‐fluoro‐1‐aryl‐hexahydro‐1H‐isochromene derivatives in good yields with excellent selectivity. This is the first report of the synthesis of fluoro‐substituted oxabicycles. In this tandem process, three reactions occur in one‐pot to leading to installation of three contiguous stereocenters.
Capillary electrophoresis reveals polyamine metabolism modulation in Leishmania (Leishmania) amazonensis wild‐type and arginase‐knockout mutants under arginine starvation
Authors: Castilho‐Martins Emerson A. , Canuto Gisele A. B. , Muxel Sandra Marcia , daSilva Maria Fernanda Laranjeira , Floeter‐Winter Lucile Maria , del Aguila Carmen , López‐Gonzálvez Ángeles , Barbas Coral
Published: July 2015

l‐Arginine is an essential amino acid in Leishmania (Leishmania) amazonensis metabolism. A key enzyme for parasite l‐arginine metabolism is arginase (ARG) that uses arginine to produce urea and ornithine, a precursor of polyamine pathway guaranteeing parasite replication in both insect and mammal hosts. There is an alternative pathway to produce ornithine via l‐proline and glutamate, but this mechanism is not described in Leishmania. In the mammal host, two enzymes can use l‐arginine as substrate, the host ARG and the induced nitric oxide synthase that produces nitric oxide. The competition between induced nitric oxide synthase and both parasite and host ARG can favor the success of the infection or its control. Here, we established the metabolomics profile of the polyamine pathway of wild type (WT) L. (L.) amazonensis, submitted or not to l‐arginine starvation, and compared to the ARG‐knockout mutant (arg−). Our results indicated that arginine starvation induces a decrease in arginine, ornithine, and putrescine, but we could not detect the significative level changes of spermidine, spermine, or agmatine. However, the absence of ARG on the arg− induced an increase of arginine and citrulline levels, but decreased the levels of ornithine and putrescine. Similarly to the WT arginine‐starved parasites, the arg− parasites presented lower levels of proline when compared to the WT ones. This could be indicative of an alternative pathway to surpass the enzyme or its substrate absence.
Chemical analysis of fish bile extracts for monitoring endocrine disrupting chemical exposure in water: Bisphenol A, alkylphenols, and norethindrone
Authors: Wu Minghong , Pan Chenyuan , Yang Ming , Xu Bentuo , Lei Xiangjie , Ma Jing , Cai Ling , Chen Jingsi
Published: July 2015

The present study determined concentrations of estrogenic bisphenol A (BPA), nonylphenol, octylphenol (4-tert-octylphenol), butylphenol (4-tert-butylphenol), and progestogenic norethindrone by liquid chromatography–tandem mass spectrometry in bile extracts from field fish from the Xin'an River and market fish in Shanghai, China. Compared with the field fish, endocrine disrupting chemical (EDC) concentrations in market fish bile were at relatively high levels with high detectable rates. The average concentrations of BPA, nonylphenol, 4-tert-octylphenol, 4-tert-butylphenol, and norethindrone in field fish bile were 30.1 µg/L, 203 µg/L, 4.69 µg/L, 7.84 µg/L, and 0.514 µg/L, respectively; in market fish bile they were 240 µg/L, 528 µg/L, 76.5 µg/L, 12.8 µg/L, and 5.26 µg/L, respectively; and in the surface water of Xin'an River they were 38.8 ng/L, 7.91 ng/L, 1.98 ng/L, 2.66 ng/L, and 0.116 ng/L, respectively. The average of total estrogenic activity of river water was 3.32 ng/L estradiol equivalents. High bioconcentration factors (BCFs) were discovered for all 5 EDCs (≧998-fold) in field fish bile. Furthermore, the authors analyzed the BCF value of BPA in fish bile after 30-d exposure to environmentally relevant concentrations of BPA in the laboratory, and the analysis revealed that BCF in fish bile (BCFFish bile) changed in an inverse concentration–dependent manner based on the log10-transformed BPA concentration in water. Strikingly, the data from the field study were well fitted within this trend. The data together suggested that analysis of fish bile extracts could be an efficient method for assessing waterborne EDCs exposure for aquatic biota. Environ Toxicol Chem 2016;35:182–190. © 2015 SETAC
Backhaul aware joint uplink and downlink user association for delay‐power trade‐offs in HetNets with hybrid energy sources
Authors: Liu Dantong , Chen Yue , Chai Kok Keong , Zhang Tiankui
Published: July 2015

In cellular networks, conventional user association algorithms are solely based on downlink (DL) performance, which may lead to inefficient transmission power and high interference in the uplink (UL) transmission. In addition, the backhaul data rate constraint has been neglected by the majority of the existing user association algorithms. However, the backhaul constraint has become more severe in heterogeneous networks (HetNets) where small cells are densely deployed to meet the skyrocketing data traffic demand. In this paper, we propose an optimal backhaul‐aware joint UL and DL user association for delay‐power trade‐offs in HetNets with hybrid energy sources. In the considered HetNets, all the base stations are assumed to be powered by a combination of power grid and renewable energy sources, in order to achieve both uninterrupted and green communications. Taking both UL and DL transmissions into consideration, the proposed user association algorithm aims to improve network quality of service by minimising the sum of UL and DL average traffic delay, as well as to reduce the overall UL power consumption of users and DL on‐grid power consumption by maximising the utilisation of green power harvested from renewable energy sources. To this end, a convex optimisation problem is formulated to minimise the weighted sum of cost of average traffic delay and cost of power consumption. We have proved that the proposed user association algorithm converges to the global optimum, which enables a flexible trade‐off between average traffic delay and power consumption. Simulation results validate the effectiveness of the proposed algorithm in adapting the traffic loads among base stations along with the distribution of green power and the backhaul data rate constraint. Simulation results also demonstrate that the proposed user association algorithm achieves prominent improvement in UL average traffic delay reduction and effectively reduces both the DL on‐grid power consumption and overall UL power consumption of users, with limited sacrifice on DL average traffic delay, compared with the user association algorithm only based on DL performance. Copyright © 2015 John Wiley & Sons, Ltd.