bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of particle shape on fluid flow and heat transfer for methane steam reforming reactions in a packed bed
Authors: Karthik G. M. , Buwa Vivek V.
Published: October 2016

Numerical simulations of a cylindrical packed bed with tube to particle diameter ratio of 1.4, containing 10 particles, were performed to understand the effect of particle shape on pressure drop, heat transfer and reaction performance. Six particle shapes namely, cylinder as the reference, trilobe and daisy having external shaping, hollow cylinder, cylcut, and 7‐hole cylinder including internal voids were chosen. Methane steam reforming reactions were considered for the heat transfer and reaction performance evaluation. The present study showed that the external shaping of particles offered lower pressure drop, but lower values of effectiveness factor indicating strong diffusion limitations. The internally shaped particles offered increased surface area, led to higher effectiveness factor and allowed to overcome the diffusion limitations. The effective heat transfer and effectiveness factor of the trilobe‐shaped particle per unit pressure drop was found to be the best among the particle shapes considered in the present work. © 2016 American Institute of Chemical Engineers AIChE J, 63: 366–377, 2017
Beta‐blockers improve survival outcomes in patients with multiple myeloma: a retrospective evaluation
Authors: Hwa Yi L. , Shi Qian , Kumar Shaji K. , Lacy Martha Q. , Gertz Morie A. , Kapoor Prashant , Buadi Francis K. , Leung Nelson , Dingli David , Go Ronald S. , Hayman Suzanne R. , Gonsalves Wilson I. , Russell Stephen , Lust John A. , Lin Yi , Rajkumar S. Vincent , Dispenzieri Angela
Published: October 2016

A preclinical study demonstrated anti‐proliferative and apoptotic effect of propranolol on multiple myeloma (MM) cell. Clinical studies suggested that beta‐blocker (BB) might impact the prognosis of breast, prostate, colorectal, ovarian, lung, and skin cancer. This retrospective study evaluated the effect of BB in MM disease‐specific survival (DSS) and overall survival (OS). Among 1,971 newly diagnosed MM patients seen at Mayo Clinic between 1995 and 2010, usage of BB and other cardiac (or antihypertensive) medications were abstracted. Cumulative incidence function and Kaplan–Meier method were used to estimate 5‐year cumulative incidence rate (CIR) of MM death and OS rate, respectively. Nine hundred and thirty (47.2%) patients had no intake of cardiac medications; 260 (13.2%) used BB alone; 343 (17.4%) used both BB/non‐BB cardiac medications; and 438 (22.2%) had non‐BB cardiac drugs. Superior MM DSS was observed in BB only users, compared to patients without any cardiac drugs (
, 0.53, 95% confidence interval [CI], 0.42–0.67, Padj.<0.0001) and non‐BB cardiac drugs users (
, 0.49, 95% CI, 0.38–0.63, Padj.<0.0001). Patients on both BB and other cardiac drugs showed superior DSS than non‐cardiac drugs users (
, 0.54, 95% CI, 0.44–0.67, Padj.<0.0001) and non‐BB cardiac drug users. (
, 0.50, 95% CI, 0.40–0.62, Padj.<0.0001). MM DSS did not differ between BB users with and without other cardiac drugs (Padj.=0.90). Multivariable analysis showed the same pattern for OS. In patients with MM, BB intake is associated with a reduced risk of disease‐specific death and overall mortality in comparison to non‐BB or no use of cardiac drugs. Am. J. Hematol. 92:50–55, 2017. © 2016 Wiley Periodicals, Inc.
Physical activity patterns and biomarkers of cardiovascular disease risk in hunter‐gatherers
Authors: Raichlen David A. , Pontzer Herman , Harris Jacob A. , Mabulla Audax Z. P. , Marlowe Frank W. , Josh Snodgrass J. , Eick Geeta , Colette Berbesque J. , Sancilio Amelia , Wood Brian M.
Published: October 2016

Objectives

Time spent in moderate‐to‐vigorous physical activity (MVPA) is a strong predictor of cardiovascular health, yet few humans living in industrialized societies meet current recommendations (150 min/week). Researchers have long suggested that human physiological requirements for aerobic exercise reflect an evolutionary shift to a hunting and gathering foraging strategy, and a recent transition to more sedentary lifestyles likely represents a mismatch with our past in terms of physical activity. The goal of this study is to explore this mismatch by characterizing MVPA and cardiovascular health in the Hadza, a modern hunting and gathering population living in Northern Tanzania.

Methods

We measured MVPA using continuous heart rate monitoring in 46 participants recruited from two Hadza camps. As part of a larger survey of health in the Hadza, we measured blood pressure (n = 198) and biomarkers of cardiovascular health (n = 23) including C‐reactive protein, cholesterol (Total, HDL, and LDL), and triglycerides.

Results

We show that Hadza participants spend large amounts of time in MVPA (134.92 ± 8.6 min/day), and maintain these activity levels across the lifespan. In fact, the Hadza engage in over 14 times as much MVPA as subjects participating in large epidemiological studies in the United States. We found no evidence of risk factors for cardiovascular disease in this population (low prevalence of hypertension across the lifespan, optimal levels for biomarkers of cardiovascular health).

Conclusions

Our results provide evidence that the hunting and gathering foraging strategy involves high levels of MVPA, supporting the evolutionary medicine model for the relationship between MVPA and cardiovascular health.
Finsler geometry of topological singularities for multi‐valued fields: Applications to continuum theory of defects
Authors: Yajima Takahiro , Nagahama Hiroyuki
Published: October 2016

Topological singularity in a continuum theory of defects and a quantum field theory is studied from a viewpoint of differential geometry. The integrability conditions of singularity (Clairaut‐Schwarz‐Young theorem) are expressed by a torsion tensor and a curvature tensor when a Finslerian intrinsic parallelism holds for the multi‐valued function. In the context of the quantum field theory, the singularity called an extended object is expressed by the torsion when the intrinsic parallelism is related to the spontaneous breakdown of symmetry. In the continuum theory of defects, the path‐dependency of point and line defects within a crystal is interpreted by the non‐vanishing condition of torsion tensor in a non‐Riemannian space osculated from the Finsler space, and the domain is not simply connected. On the other hand, for the rotational singularity, an energy integral (J‐integral) around a disclination field is path‐independent when a nonlinear connection is single‐valued. This means that the topological expression for the sole defect (Gauss‐Bonnet theorem with genus ) is understood by the integrability of nonlinear connection.

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Silyl Formates as Surrogates of Hydrosilanes and Their Application in the Transfer Hydrosilylation of Aldehydes
Authors: Chauvier Clément , Thuéry Pierre , Cantat Thibault
Published: October 2016

Silyl formates are investigated for the first time as surrogates of hydrosilanes. In the presence of a well‐defined ruthenium catalyst, these reagents are shown to promote the chemoselective reduction of a variety of aldehydes by transfer hydrosilylation. Mechanistic investigations have shown that genuine hydrosilane species are avoided during catalysis. The mechanism involves a sequence of decarboxylation/insertion/transmetallation steps.
Characterization and Reactivity Studies of a Terminal Copper–Nitrene Species
Authors: Corona Teresa , Ribas Lídia , Rovira Mireia , Farquhar Erik R. , Ribas Xavi , Ray Kallol , Company Anna
Published: October 2016

High‐valent terminal copper–nitrene species have been postulated as key intermediates in copper‐catalyzed aziridination and amination reactions. The high reactivity of these intermediates has prevented their characterization for decades, thereby making the mechanisms ambiguous. Very recently, the Lewis acid adduct of a copper–nitrene intermediate was trapped at −90 °C and shown to be active in various oxidation reactions. Herein, we describe for the first time the synthesis and spectroscopic characterization of a terminal copper(II)–nitrene radical species that is stable at room temperature in the absence of any Lewis acid. The azide derivative of a triazamacrocyclic ligand that had previously been utilized in the stabilization of aryl–CuIII intermediates was employed as an ancillary ligand in the study. The terminal copper(II)–nitrene radical species is able to transfer a nitrene moiety to phosphines and abstract a hydrogen atom from weak C−H bonds, leading to the formation of oxidized products in modest yields.
A Cooperative Strategy for the Highly Selective Intermolecular Oxycarbonylation Reaction of Alkenes using a Palladium Catalyst
Authors: Li Ming , Yu Feng , Qi Xiaoxu , Chen Pinhong , Liu Guosheng
Published: October 2016

A novel method for intermolecular functionalization of terminal and internal alkenes has been designed. The electrophilic reagent, hypervalent iodine, plays a key role in this process by activating the alkene C=C bond for nucleophilic addition of the palladium catalyst. This process generates an iodonium‐containing palladium species which undergoes CO insertion. The new approach, intermolecular oxycarbonylaton reactions of alkenes, has been achieved and carried out under mild reaction conditions to produce the corresponding β‐oxycarbonylic acids with excellent efficiencies and levels of regio‐ and diastereoselectivity.
Solvens‐induzierte reduktive Aktivierung von CO2 durch Bismut und Änderung des Reaktionsprodukts von Metalloformiat nach Oxalat
Authors: Thompson Michael C. , Ramsay Jacob , Weber J. Mathias
Published: October 2016

Es wurde untersucht, wie sich die reduktive Aktivierung von CO2 durch einen atomaren Bi‐Modellkatalysator unter aprotischer Solvatisierung verändert. Infrarot‐Photodissoziationsspektroskopie massenselektierter [Bi(CO2)n]−‐Clusterionen wurde genutzt, um die Strukturveränderung der molekularen ionischen Kerne dieser Cluster bei wachsender Clustergröße zu verfolgen. Die Interpretation der Infrarotspektren erfolgte durch Vergleich mit Ergebnissen auf der Basis von Dichtefunktionaltheorie. Die Resultate zeigen, dass CO2 mit Bi in Gegenwart eines Zusatzelektrons ein Metalloformiat‐Ion (BiCOO−) bildet. Solvatisierung durch zusätzliche CO2‐Moleküle führt zur Stabilisierung eines BiI‐Oxalat‐Komplexes und damit zur Änderung des Kernions.
Direct Synthesis of Pyrroles by Dehydrogenative Coupling of Diols and Amines Catalyzed by Cobalt Pincer Complexes
Authors: Daw Prosenjit , Chakraborty Subrata , Garg Jai Anand , Ben‐David Yehoshoa , Milstein David
Published: October 2016

Herein, the first example of base‐metal‐catalyzed dehydrogenative coupling of diols and amines to selectively form functionalized 1,2,5‐substituted pyrroles liberating water and hydrogen gas as the sole by‐products is presented. The reaction is catalyzed by pincer complexes of earth‐abundant cobalt.
Convergent Assembly of the Tetracyclic Meroterpenoid (−)‐Cyclosmenospongine by a Non‐Biomimetic Polyene Cyclization
Authors: Speck Klaus , Wildermuth Raphael , Magauer Thomas
Published: October 2016

The cationic cyclization of polyenes constitutes a powerful and elegant transformation, which has been utilized by nature's biosynthetic machinery for the construction of complex polycyclic terpenoids. Previous studies by chemists to mimic this cyclization in the laboratory were limited to different modes of activation using biosynthetic‐like precursors, which accommodate only simple methyl‐derived substituents. Here we describe the development of an unprecedented and highly efficient polyene cyclization of an aryl enol ether containing substrate. The cyclization was shown to proceed in a stepwise manner to generate three rings and three consecutive stereocenters, two of which are tetrasubstituted, in a single flask. The developed transformation is of great synthetic value and has enabled the convergent assembly of the tetracyclic meroterpenoid (−)‐cyclosmenospongine.
Absolut minimales Sampling in der hochdimensionalen NMR‐Spektroskopie
Authors: Hansen Alexandar L. , Brüschweiler Rafael
Published: October 2016

Standardmäßige dreidimensionale (3D‐)Fourier‐Transformations(FT)‐NMR‐Experimente von molekularen Systemen erfordern häufig lange Messzeiten, die durch das umfangreiche Sampling entlang der indirekten Zeitbereiche verursacht werden, damit eine hinreichende spektrale Auflösung erhalten werden kann. In den letzten Jahren wurde eine Fülle von alternativen Sampling‐Methoden vorgeschlagen, um diesen Engpass zu vermeiden. Aufgrund ihrer algorithmischen Komplexität für vorgegebene NMR‐Proben und Experimente ist es jedoch häufig schwierig, die minimale Abtastinformation und die damit verbundene minimale Messzeit zu bestimmen. Hier wird die Methode des absoluten minimalen Samplings (AMS) vorgestellt, die auf gängige 3D‐NMR‐Experimente angewendet werden kann. Für die Proteine Ubiquitin und Arginin‐Kinase wird gezeigt, wie man für das weitverbreitete 3D‐HNCO‐Experiment präzise Kohlenstofffrequenzen mithilfe eines einzigen Zeitinkrements erhält, während für andere, z. B. das 3D‐HN(CA)CO‐Experiment, alle relevanten Informationen in nur sechs Schritten erhältlich sind, wodurch eine Beschleunigung um einen Faktor 7–50 erreicht wird.
Strukturelle Grundlage der Transkription: 10 Jahre nach dem Chemie‐Nobelpreis
Authors: Hantsche Merle , Cramer Patrick
Published: October 2016

In allen lebenden Zellen bildet die Transkription den ersten Schritt der Expression genetischer Information. Ihrer Regulation unterliegen Zelldifferenzierung, Morphogenese sowie Antworten auf Umweltveränderungen. Während der Transkription verwendet das Enzym RNA‐Polymerase DNA als Vorlage, um eine komplementäre RNA‐Kopie von einem Gen herzustellen. Wir beschreiben die Entwicklungen in unserem strukturellen Verständnis der Transkription in Eukaryoten, die in den letzten 10 Jahren nach der Verleihung des Nobelpreises für Chemie an Roger Kornberg im Jahr 2006 erzielt wurden. Eine Aufklärung der Transkriptionsinitiation und ‐elongation zeichnet sich ab, wohingegen die Mechanismen der Transkriptionsregulation weitgehend unverstanden bleiben. In diesem Feld wurden strukturbiologische Hybridmethoden entwickelt, die verschiedene Techniken zur Bestimmung der dreidimensionalen Architektur von großen und transienten makromolekularen Komplexen kombinieren.
A Rapid Microwave‐Assisted Thermolysis Route to Highly Crystalline Carbon Nitrides for Efficient Hydrogen Generation
Authors: Guo Yufei , Li Jing , Yuan Yupeng , Li Lu , Zhang Mingyi , Zhou Chenyan , Lin Zhiqun
Published: October 2016

Highly crystalline graphitic carbon nitride (g‐C3N4) with decreased structural imperfections benefits from the suppression of electron–hole recombination, which enhances its hydrogen generation activity. However, producing such g‐C3N4 materials by conventional heating in an electric furnace has proven challenging. Herein, we report on the synthesis of high‐quality g‐C3N4 with reduced structural defects by judiciously combining the implementation of melamine–cyanuric acid (MCA) supramolecular aggregates and microwave‐assisted thermolysis. The g‐C3N4 material produced after optimizing the microwave reaction time can effectively generate H2 under visible‐light irradiation. The highest H2 evolution rate achieved was 40.5 μmol h−1, which is two times higher than that of a g‐C3N4 sample prepared by thermal polycondensation of the same supramolecular aggregates in an electric furnace. The microwave‐assisted thermolysis strategy is simple, rapid, and robust, thereby providing a promising route for the synthesis of high‐efficiency g‐C3N4 photocatalysts.
A Counterion‐Directed Approach to the Diels–Alder Paradigm: Cascade Synthesis of Tricyclic Fused Cyclopropanes
Authors: Kiss Emily , Campbell Craig D. , Driver Russell W. , Jolliffe John D. , Lang Rosemary , Sergeieva Tetiana , Okovytyy Sergiy , Paton Robert S. , Smith Martin D.
Published: October 2016

An approach to the intramolecular Diels–Alder reaction has led to a cascade synthesis of complex carbocycles composed of three fused rings and up to five stereocenters with complete stereocontrol. Computational analysis reveals that the reaction proceeds by a Michael/Michael/cyclopropanation/epimerization cascade in which size and coordination of the counterion is key.
Accessing Drug Metabolites via Transition‐Metal Catalyzed C−H Oxidation: The Liver as Synthetic Inspiration
Authors: Genovino Julien , Sames Dalibor , Hamann Lawrence G. , Touré B. Barry
Published: October 2016

Can classical and modern chemical C−H oxidation reactions complement biotransformation in the synthesis of drug metabolites? We have surveyed the literature in an effort to try to answer this important question of major practical significance in the pharmaceutical industry. Drug metabolites are required throughout all phases of the drug discovery and development process; however, their synthesis is still an unsolved problem. This Review, not intended to be comprehensive or historical, highlights relevant applications of chemical C−H oxidation reactions, electrochemistry and microfluidic technologies to drug templates in order to access drug metabolites, and also highlights promising reactions to this end. Where possible or appropriate, the contrast with biotransformation is drawn. In doing so, we have tried to identify gaps where they exist in the hope to spur further activity in this very important research area.
Exceptionally Selective and Tunable Sensing of Guanine Derivatives and Analogues by Structural Complementation in a G‐Quadruplex
Authors: Li Xin‐min , Zheng Ke‐wei , Hao Yu‐hua , Tan Zheng
Published: October 2016

A guanine‐vacancy‐bearing G‐quadruplex (GVBQ) interacts with guanine and derivatives by a structural complementation to form a more stable and intact G‐quadruplex. Sensors using GVBQs are devised to detect guanine and other nucleobases, and their derivatives derived from structurally similar compounds. A strict requirement of Hoogsteen hydrogen bonds between the GVBQ and analyte in the structural complementation confers exceptional selectivity on the analyte. As such, subtle modifications on analytes affecting even a single hydrogen bond can preclude the recognition. In principle, the strategy may also be expanded to detect many planar cyclic compounds. Because nucleobases and derivatives/metabolites are involved in many physiological and pathological processes, this type of sensor may find applications in risk assessment of pathogenesis and therapeutics related to nucleic acid metabolism.
Solvent‐Driven Reductive Activation of CO2 by Bismuth: Switching from Metalloformate Complexes to Oxalate Products
Authors: Thompson Michael C. , Ramsay Jacob , Weber J. Mathias
Published: October 2016

In this work, we investigated how the reductive activation of CO2 with an atomic bismuth model catalyst changes under aprotic solvation. IR photodissociation spectroscopy of mass‐selected [Bi(CO2)n]− cluster ions was used to follow the structural evolution of the core ion with increasing cluster size. We interpreted the IR spectra by comparison with density‐functional‐theory calculations. The results show that CO2 binds to a bismuth atom in the presence of an excess electron to form a metalloformate ion, BiCOO−. Solvation with additional CO2 molecules leads to the stabilization of a bismuth(I) oxalate complex and results in a core ion switch.
Bilayer Networks within a Hydrogel Shell: A Robust Chassis for Artificial Cells and a Platform for Membrane Studies
Authors: Baxani Divesh K. , Morgan Alex J. L. , Jamieson William D. , Allender Christopher J. , Barrow David A. , Castell Oliver K.
Published: October 2016

The ability to make artificial lipid bilayers compatible with a wide range of environments, and with sufficient structural rigidity for manual handling, would open up a wealth of opportunities for their more routine use in real‐world applications. Although droplet interface bilayers (DIBs) have been demonstrated in a host of laboratory applications, from chemical logic to biosynthesis reaction vessels, their wider use is hampered by a lack of mechanical stability and the largely manual methods employed in their production. Multiphase microfluidics has enabled us to construct hierarchical triple emulsions with a semipermeable shell, in order to form robust, bilayer‐bound, droplet networks capable of communication with their external surroundings. These constructs are stable in air, water, and oil environments and overcome a critical obstacle of achieving structural rigidity without compromising environmental interaction. This paves the way for practical application of artificial membranes or droplet networks in diverse areas such as medical applications, drug testing, biophysical studies and their use as synthetic cells.
A Self‐Healing Aqueous Lithium‐Ion Battery
Authors: Zhao Yang , Zhang Ye , Sun Hao , Dong Xiaoli , Cao Jingyu , Wang Lie , Xu Yifan , Ren Jing , Hwang Yunil , Son In Hyuk , Huang Xianliang , Wang Yonggang , Peng Huisheng
Published: October 2016

Flexible lithium‐ion batteries are critical for the next‐generation electronics. However, during the practical application, they may break under deformations such as twisting and cutting, causing their failure to work or even serious safety problems. A new family of all‐solid‐state and flexible aqueous lithium ion batteries that can self‐heal after breaking has been created by designing aligned carbon nanotube sheets loaded with LiMn2O4 and LiTi2(PO4)3 nanoparticles on a self‐healing polymer substrate as electrodes, and a new kind of lithium sulfate/sodium carboxymethylcellulose serves as both gel electrolyte and separator. The specific capacity, rate capability, and cycling performance can be well maintained after repeated cutting and self‐healing. These self‐healing batteries are demonstrated to be promising for wearable devices.
p‐Azidophenylarsenoxide: An Arsenical “Bait” for the In Situ Capture and Identification of Cellular Arsenic‐Binding Proteins
Authors: Yan Xiaowen , Li Jinhua , Liu Qingqing , Peng Hanyong , Popowich Aleksandra , Wang Zhixin , Li Xing‐Fang , Le X. Chris
Published: October 2016

Identification of arsenic‐binding proteins is important for understanding arsenic health effects and for developing arsenic‐based therapeutics. We report here a strategy for the capture and identification of arsenic‐binding proteins in living cells. We designed an azide‐labeled arsenical, p‐azidophenylarsenoxide (PAzPAO), to serve bio‐orthogonal functions: the trivalent arsenical group binds to cellular proteins in situ, and the azide group facilitates click chemistry with dibenzylcyclooctyne. The selective and efficient capture of arsenic‐binding proteins enables subsequent enrichment and identification by shotgun proteomics. Applications of the technique are demonstrated using the A549 human lung carcinoma cells and two in vitro model systems. The technique enables the capture and identification of 48 arsenic‐binding proteins in A549 cells incubated with PAzPAO. Among the identified proteins are a series of antioxidant proteins (e.g., thioredoxin, peroxiredoxin, peroxide reductase, glutathione reductase, and protein disulfide isomerase) and glyceraldehyde‐3‐phosphate dehydrogenase. Identification of these functional proteins, along with studies of arsenic binding and enzymatic inhibition, points to these proteins as potential molecular targets that play important roles in arsenic‐induced health effects and in cancer treatment.
New Design of a Disulfurating Reagent: Facile and Straightforward Pathway to Unsymmetrical Disulfanes by Copper‐Catalyzed Oxidative Cross‐Coupling
Authors: Xiao Xiao , Feng Minghao , Jiang Xuefeng
Published: October 2016

A novel reagent, which introduces two sulfur atoms in one step, was designed and used for the construction of diverse disulfanes by copper‐catalyzed oxidative cross‐coupling under mild reaction conditions. By applying this stable and readily prepared reagent, late‐stage modification of pharmaceuticals and natural products can be achieved straightforward. The scaled‐up experiments further indicated the practicality of this protocol. The pH value of the system plays a key role in achieving highly selective cleavage of the C−S bond instead of a S−S bond in the transformation.
Catalytic Asymmetric Piancatelli Rearrangement: Brønsted Acid Catalyzed 4π Electrocyclization for the Synthesis of Multisubstituted Cyclopentenones
Authors: Cai Yunfei , Tang Yurong , Atodiresei Iuliana , Rueping Magnus
Published: October 2016

The first catalytic asymmetric Piancatelli reaction is reported. Catalyzed by a chiral Brønsted acid, the rearrangement of a wide range of furylcarbinols with a series of aniline derivatives provides valuable aminocyclopentenones in high yields as well as excellent enantioselectivities and diastereoselectivities. The high value of the aza‐Piancatelli rearrangement was demonstrated by the synthesis of a cyclopentane‐based hNK1 antagonist analogue.
Absolute Minimal Sampling in High‐Dimensional NMR Spectroscopy
Authors: Hansen Alexandar L. , Brüschweiler Rafael
Published: October 2016

Standard three‐dimensional Fourier transform (FT) NMR experiments of molecular systems often involve prolonged measurement times due to extensive sampling required along the indirect time domains to obtain adequate spectral resolution. In recent years, a wealth of alternative sampling methods has been proposed to ease this bottleneck. However, due to their algorithmic complexity, for a given sample and experiment it is often hard to determine the minimal sampling requirement, and hence the maximal achievable experimental speed up. Herein we introduce an absolute minimal sampling (AMS) method that can be applied to common 3D NMR experiments. We show for the proteins ubiquitin and arginine kinase that for widely used experiments, such as 3D HNCO, accurate carbon frequencies can be obtained with a single time increment, while for others, such as 3D HN(CA)CO, all relevant information is obtained with as few as 6 increments amounting to a speed up of a factor 7–50.
Copper Salt‐Controlled Divergent Reactivity of [Cu]CF2PO(OEt)2 with α‐Diazocarbonyl Derivatives
Authors: Ivanova Maria V. , Bayle Alexandre , Besset Tatiana , Pannecoucke Xavier , Poisson Thomas
Published: October 2016

Herein, we report a copper salt‐controlled divergent reactivity toward α‐diazocarbonyl compounds. By a simple change of the copper counteranion under identical reaction conditions, the reported method allowed an easy access to either (Z)‐α‐fluorovinylphosphonate or alkyl‐SCF2PO(OEt)2 derivatives in good yields. Mechanistic studies were performed and suggested two different pathways to explain the formation of these products.
Silica‐coated nano‐Fe3O4‐supported iminopyridine palladium complex as an active, phosphine‐free and magnetically separable catalyst for Heck reactions
Authors: Zhang Qiang , Zhao Xin , Wei Huai‐Xin , Li Ji‐Hang , Luo Jun
Published: October 2016

A novel magnetic nanoparticle‐supported iminopyridine palladium complex was successfully prepared by attaching palladium acetate to iminopyridine ligand‐functionalized silica‐coated nano‐Fe3O4. The as‐prepared catalyst was well characterized and was evaluated in Heck reactions in terms of activity and recyclability. It was found to be highly efficient for the reactions of various aryl iodides and aryl bromides having electron‐withdrawing groups with olefins under phosphine‐free and inert atmosphere‐free conditions. Moreover, the catalyst could be conveniently recovered using an external magnet, and the recyclability was influenced by the base in the Heck reaction. The catalyst could be reused at least six times with no significant loss in activity when triethylamine acted as the base.
Greener approach for synthesis of monodispersed palladium nanoparticles using aqueous extract of green tea and their catalytic activity for the Suzuki–Miyaura coupling reaction and the reduction of nitroarenes
Authors: Veisi Hojat , Rostami Amin , Shirinbayan Mohadeseh
Published: October 2016

A facile and green route for the synthesis of palladium nanoparticles (NPs) was developed utilizing non‐toxic and renewable natural green tea extract as the reducing, stabilizing and capping agent. The as‐prepared Pd‐NPs@G.Tea extract was characterized using UV–visible spectroscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, field‐emission scanning electron microscopy, transmission electron microscopy and energy‐dispersive X‐ray spectroscopy. The Pd‐NPs@G.Tea extract could be used as an efficient and heterogeneous catalyst for Suzuki coupling reactions between phenylboronic acid and a range of aryl halides containing iodo, bromo and chloro moieties, and also for the reduction of nitroarenes using sodium borohydride in an environmentally friendly medium. Excellent yields of products were obtained with a wide range of substrates and the catalyst was recycled multiple times without any significant loss of its catalytic activity.
Synthesis and structural characterization of new bioactive ligands and their Bi(III) derivatives
Authors: Raheel Ahmad , Imtiaz‐ud‐Din  , Andleeb Sohaila , Ramadan Simko , Tahir Muhammad Nawaz
Published: October 2016

Five new carboxylic acid precursors bearing thiourea group and their corresponding bismuth(III) complexes were synthesized and characterized using CHNS and inductively coupled plasma analyses and infrared and NMR (1H, 13C) spectroscopies. Single‐crystal X‐ray diffraction analysis was also carried out for one of the precursors. The behaviour of the compounds was bioassayed for antibacterial, antifungal, antioxidant and enzyme (lipoxygenase, α‐glycosidase and anti‐urease) inhibition activities. It is concluded that the interaction of the compounds with bismuth enhances both the antimicrobial and enzyme inhibition activities. The synthesized compounds may prove to be good therapeutic agents.
Factors that enable the formation of porous strut morphology in “Swiss Cheese” viscoelastic polyurethane foam technology
Authors: Aou Kaoru , Gamboa Rogelio R. , Obi Bernard E. , Cook Renee , Latham Dwight D.
Published: October 2016

Several factors were investigated that affect porous strut morphology in the Highly Porous Supersoft Viscoelastic Foam. Porous strut morphology and high air permeability of the Swiss‐Cheese TDI VE technology were found to be enabled by the combination of immiscible polyether polyols mixed with a third, highly hydrophobic polyol of high equivalent weight that is immiscible with either of the first two polyether polyols. Completely “punctured through” pores in struts were observed more frequently in foam samples where an isocyanate index of 90 versus 100 was employed. When isocyanate index is fixed to 90, it was found that a poly(1,2‐butylene oxide) (“PBO”) monol level of ≥3.0 parts per hundred polyol (pphp) was needed to see the first signs of a “punctured” pore strut morphology. Studies show that a “high‐Eq.Wt.‐hydrophobic‐polyol‐leaving‐voids” model is consistent with observed results. Hydrophobic polyols that allowed the formation of porous strut morphology included BO‐4000 monol (Eq.Wt. ∼ 4000) and PBD‐10000 diol (Eq.Wt. ∼ 5000). The use of these hydrophobic polyols also yielded air flows that were significantly higher than those obtained with the “standard” viscoelastic foam formulations that were prepared at the same isocyanate index. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44449.
Preparation of gel resins and removal of copper and lead from water
Authors: Yin Xiao‐Chun , Liu Xiong , Fan Jing‐Chun , Wu Jian‐Jun , Men Jun‐Liang , Zheng Gui‐Seng
Published: October 2016

A series of gel resins were prepared by polymerizing glycidyl methacrylate (GMA) and 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and functionalizing with ammonia (NH3) and tetraethylenepentamine (TEPA). The aminated gel resins were then used as an adsorbent for the removal of heavy metal ions (Cu2+ and Pb2+). These gel resins containing amino groups and chelating amino groups had excellent adsorptive properties for Cu2+ and Pb2+. The adsorption process reached equilibrium in 40 min, and the adsorption capacities of Cu2+ and Pb2+ were 75.0 mg g−1 and 266.6 mg g−1 for the NH3‐aminated gel resins and 57.5 mg g−1 and 330.6 mg g−1 for the TEPA‐aminated gel resins, respectively. After five adsorption–desorption processes, the adsorption capacities only decreased slightly. Thus, these aminated gel resins can be used as effective adsorbents for aqueous heavy metal ions (Cu2+ and Pb2+). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44466.
Effect of nanoparticles on the mechanical properties of acrylonitrile–butadiene–styrene specimens fabricated by fused deposition modeling
Authors: Meng Shuna , He Hui , Jia Yunchao , Yu Peng , Huang Bai , Chen Jian
Published: October 2016

Acrylonitrile–butadiene–styrene (ABS) nanocomposite filaments with different inorganic nanofillers for fused deposition modeling (FDM) were prepared by melting extrusion and printed via a commercial FDM three‐dimensional printer. The effects of the nanoparticles on the mechanical strength, anisotropy, and thermal properties of the ABS specimens were evaluated. The performances of the virgin ABS samples manufactured by FDM and injection molding were also studied. The results show that the tensile strength (TS) of the pure ABS made by FDM was just up to 70% of the value obtained from the injection‐molded specimens. The mechanical anisotropy of the pure ABS samples was very evident when the building orientation was changed. However, we found that the addition of nanofillers significantly reduced the mechanical anisotropy and improved the mechanical strength and thermostability of the ABS samples fabricated by FDM technology. The TS and flexural strength of the ABS samples increased by 25.7 and 17.1%, respectively, with the introduction of nanomontmorillonite. The addition of nano calcium carbonate lowered the mechanical anisotropy of ABS from 42.1 to 23.9%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44470.
Static adsorption and dynamic retention of an anti‐salinity polymer in low permeability sandstone core
Authors: Li Qinzhi , Pu Wanfen , Wei Bing , Jin Fayang , Li Kexing
Published: October 2016

The technical viability of enhancing oil recovery (EOR) using polymer flooding has been verified. Through correcting the unfavorable mobility ratio, polymer flooding could significantly improve the macroscopic sweep efficiency of waterflooding, which makes it attractive in middle to high permeability reservoirs. However, as the depletion of these easy‐to‐produce resources, the interests of oil industry will be diverted to low permeability reservoirs and polymer flooding is believed to be one of the key methods for this type of reservoir. To meet this technological tendency, the current work investigated the applicability of an anti‐salinity polymer (KYPAM) in low permeability sandstone reservoirs. The interactions between polymer and sandstone surface including static adsorption and dynamic retention were addressed. Static adsorption data proved that the adsorptive behavior of this anti‐salinity polymer was closely related to molecular weight and concentration. The quantity of the detained KYPAM polymer in the sandstone core rapidly increased once the permeability dropped below 38 mD. High molecular weight KYPAM experienced noticeable retention compared with low molecular weight polymers resulting from the large hydrodynamic size. Due to polymer retention, the permeability of the sandstone core was significantly influenced particularly for the low permeability cores. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44487.
Semianalytical models to predict the crystallization kinetics of thermoplastic fibrous composites
Authors: Durin Audrey , Boyard Nicolas , Bailleul Jean‐Luc , Billon Noëlle , Chenot Jean‐Loup , Haudin Jean‐Marc
Published: October 2016

The growing interest for continuous fiber‐reinforced polymer composites leads to the development of new processes such as resin transfer molding for thermoplastics (RTM‐TP) or tape placement. In the aim of optimization, their simulations are required and have to include all involved physical phenomena and the associated couplings. During the consolidation step, the crystallization of the semicrystalline matrix occurs between the fibers of the multiscale reinforcement. A tricky task is to provide a realistic model able to describe the crystallization kinetics, which includes the effect of fibers on the polymer phase change and avoiding large computation time. In 2004, Haudin and Chenot proposed a generalization of the Avrami model, written in a differential form to compute the evolution of the crystallization of a neat thermoplastic in an infinite volume. In the present article, new extensions are proposed to predict the crystallization in long‐fiber thermoplastic composites, without or in the presence of transcrystallinity on fiber surfaces. In both cases, they are compared to three‐dimensional numerical simulations using a previously validated numerical method. All the numerical and analytical results are consistent. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2017,134, 44508.
Preparation and properties of 4,4′‐(hexafluoroisopropylidene) diphenol cured 2,2‐bis(4‐cyanatophenyl) propane
Authors: Hou Defa , Ma Hanbing , Li Xiuyun , He Jie , Liao Huiwei
Published: October 2016

A novel easily curing system of 2,2‐bis(4‐cyanatophenyl) propane(BACY) was prepared by employing 4,4′‐(Hexafluoroisopropylidene) Diphenol (BPAF) as modifier. The curing efficiency of BPAF was evaluated by means of differential scanning calorimetry (DSC) and Fourier translation infrared spectroscopy analysis (FTIR). It was found that the exothermic peak temperature (Tp) was 168 °C when the content of BPAF/BACY was 15/85 by weight, while the temperature of BACY was 215 °C under the same conditions when trace of cobalt(III) acetylacetonate(CoAt(III)) was added. Besides, BPAF/BACY system owned outstanding properties including excellent curing characteristics, high shear strength, remarkable dielectric properties and high thermal stability in contrast to BACY, 4,4′‐(1‐methylethylidene) bisphenol(BPA)/BACY, and nonylphenol(NoP)/BACY systems. Moreover, the properties of cured BPAF/BACY modified by different proportions of BPAF were studied in detail. It was shown that moderate BPAF was conducive to most properties of polycyanurate, and the optimal proportion of BPAF/BACY was 15/85 by weight. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44518.
Tunable thermal degradation and refractive index of poly(norbornene sulfone)s via two different polymerization methods
Authors: Liu Xin , Zhi Yunfei , Shan Shaoyun , Su Hongying , Jia Qingming
Published: October 2016

A novel polysulfone was easily synthesized by alternating copolymerization of norbornene with sulfur dioxide (SO2) via free radical copolymerization and coordination copolymerization. Compared with other olefin derivatives, norbornene is a cyclic olefin having a larger steric hindrance, which is easily copolymerized with SO2, and the obtained poly(norbornene sulfone)s have excellent thermomechanical and optical properties. The effect of the different polymerization methods on the copolymerization reaction was analyzed in detail. The results suggested that different polymerization mechanisms exist in the different polymerization methods and affect the thermal stability and optical properties of the polysulfone. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44534.
Anatomical Variation of the Tarsus in Common Inbred Mouse Strains
Authors: Richbourg Heather A. , Martin Matthew J. , Schachner Emma R. , McNulty Margaret A.
Published: October 2016

Rodent models are used for a variety of orthopedic research applications; however, anatomy references include mostly artistic representations. Advanced imaging techniques, including micro‐computed tomography (microCT), can provide more accurate representations of subtle anatomical characteristics. A recent microCT atlas of laboratory mouse (Mus musculus) anatomy depicts the central and tarsal bone III (T3) as a single bone, differing from previous references. Fusion of tarsal bones is generally characterized as pathological secondary to mutations associated with growth factors, and normal variation has not been documented in the mouse tarsus. Therefore, it is unclear if this fusion is a normal or a pathological characteristic. The aim of this study is to characterize the tarsus of the laboratory mouse and compare it to the rat and selected outgroup species (i.e., white‐footed mouse) via microCT and histology to determine if the central and T3 are separate or fused into a single bone. Laboratory mice (C57/Bl6 [n = 17] and BalbC [n = 2]) and rats (n = 5) were scanned with microCT. A representative laboratory mouse from each strain was evaluated histologically via serial sagittal sections through the mid‐tarsus. General pedal anatomy was similar between all species; however, the central and T3 bones were fused in all laboratory mice but not the rat or white‐footed mouse. A band of hyaline cartilage was identified within the fused bone of the laboratory mice. We conclude that the fusion found is a normal characteristic in laboratory mice, but timing of the fusion remains ambiguous. Anat Rec, 300:450–459, 2017. © 2016 Wiley Periodicals, Inc.
Enhancing the Performance of Dye‐Sensitized Solar Cells with a Gold‐Nanoflowers Box
Authors: Zhang Lu , Wang Zhong‐Sheng
Published: October 2016

To improve the electron collection, electron lifetime, and light‐harvesting efficiency of dye‐sensitized solar cells simultaneously, Au nanoflowers were prepared and used to cover the entire TiO2 film. Deposition of Au nanoflowers around the TiO2 film formed a light‐scattering “box” that covered the entire TiO2 film. Compared with a light‐scattering layer that only covers the top surface of TiO2, the Au‐nanoflowers box exhibited better light‐harvesting efficiency due to omnidirectional light scattering, faster electron transport (attributed to the formation of electron channels between the metallic Au nanoflowers and the electron‐collection electrode), and slower charge recombination. As a consequence, the short‐circuit photocurrent and open‐circuit photovoltage were both enhanced significantly, which improved the power conversion efficiency from 8.12 to 10.91 % (34 %) when an Au‐nanoflowers box was wrapped around the photoanode.
Security design and firm dynamics under long‐term moral hazard
Authors: Messa Alexandre
Published: October 2016

This paper addresses a moral hazard problem in which the agent's actions affect the future profits of the firm. The optimal contract can be implemented through the issuance of variable coupon debt and purchase of fixed‐coupon debt. Consequently, the resulting capital structure acts as a hedge for the firm, reducing underinvestment costs in bad states of nature and controlling overinvestment incentives in good ones. However, owing to asymmetric information between the firm's manager and investors, this hedge is only partial. The firm's investments vary with cash flows, disclosing the agent's asymmetric information to the principal. Copyright © 2016 John Wiley & Sons, Ltd.
G‐protein‐coupled receptor signaling and neural tube closure defects
Authors: Shimada Issei S. , Mukhopadhyay Saikat
Published: October 2016

Disruption of the normal mechanisms that mediate neural tube closure can result in neural tube defects (NTDs) with devastating consequences in affected patients. With the advent of next‐generation sequencing, we are increasingly detecting mutations in multiple genes in NTD cases. However, our ability to determine which of these genes contribute to the malformation is limited by our understanding of the pathways controlling neural tube closure. G‐protein‐coupled receptors (GPCRs) comprise the largest family of transmembrane receptors in humans and have been historically favored as drug targets. Recent studies implicate several GPCRs and downstream signaling pathways in neural tube development and closure. In this review, we will discuss our current understanding of GPCR signaling pathways in pathogenesis of NTDs. Notable examples include the orphan primary cilia‐localized GPCR, Gpr161 that regulates the basal suppression machinery of sonic hedgehog pathway by means of activation of cAMP‐protein kinase A signaling in the neural tube, and protease‐activated receptors that are activated by a local network of membrane‐tethered proteases during neural tube closure involving the surface ectoderm. Understanding the role of these GPCR‐regulated pathways in neural tube development and closure is essential toward identification of underlying genetic causes to prevent NTDs. Birth Defects Research 109:129–139, 2017. © 2016 Wiley Periodicals, Inc.
Effects of combined treatment with ibandronate and pulsed electromagnetic field on ovariectomy‐induced osteoporosis in rats
Authors: Zhou Jun , Liao Yuan , Xie Haitao , Liao Ying , Zeng Yahua , Li Neng , Sun Guanghua , Wu Qi , Zhou Guijuan
Published: October 2016

Ibandronate (IBN) and pulsed electromagnetic field (PEMF) have each shown positive effects for treating osteoporosis, but no study has evaluated the relative effects of these treatments combined. This study investigated the effects of IBN + PEMF on bone turnover, mineral density, microarchitecture, and biomechanical properties in an ovariectomized (OVX) rat model of osteoporosis. Fifty 3‐month‐old rats were randomly apportioned to receive a sham‐operation (n = 10), or ovariectomy (n = 40). The latter group was equally divided as the model (OVX control) or to receive IBN, PEMF, or IBN + PEMF. Beginning the day after surgery, the IBN and IBN + PEMF groups received weekly subcutaneous IBN; the PEMF and IBN + PEMF groups were given daily PEMF during the same 12 weeks. After 12 weeks of treatments, biochemical parameters, bone mineral density (BMD), microarchitecture parameters, biomechanical properties, and some metabolic modulators that are involved in bone resorption were compared. The L5 lumbar vertebral body BMDs of the IBN, PEMF, and IBN + PEMF groups were 121.6%, 119.5%, and 139.6%; maximum loads were 111.4%, 112.7%, and 121.9%; and energy to failure was 130.8%, 129.2%, and 154.9% of the OVX model, respectively. The IBN + PEMF group had significantly lower levels of serum tartrate‐resistant acid phosphatase 5b, and greater improvement in BMD, bone microarchitecture, and strength of the lumbar spine compared with monotherapy groups. Results showed that IBN + PEMF had a more favorable effect on the lumbar spine in this osteoporosis model than did either monotherapy. Bioelectromagnetics. 38:31–40, 2017. © 2016 Wiley Periodicals, Inc.
Study on physisorption between G‐actin and amphiphilic polymer‐coated gold nanoparticles
Authors: Du Qiqige , Li Wanrong , Yuan Ming , Gong Pei , Zhang Yi , Zhang Feng
Published: October 2016

Physisorptions occurs everywhere and constantly in living organisms and between nanomaterials and biomolecules. In this study, one of the most important proteins, G‐actin, was selected to investigate its bio‐nano physisorption with a model nanoparticle coated with a amphiphilic polymer. Using a photoluminescence quenching method, both the binding constant and the Hill constant were determined as 1.79 × 107 M−1 and 0.84, respectively. Thermodynamic calculations proved that such a physisorption was a spontaneous procedure. The physisorption‐mediated protein–nanoparticle conjugates were robust enough to resist gel electrophoresis, and protein conformation was kept intact, as revealed using circular dichroism. This conjugate might be a promising candidate for nanofabrication or could play a significant role in actin–related bioactivities.