bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multicomponent Approach to Silica‐Grafted Peptide Catalysts: A 3 D Continuous‐Flow Organocatalytic System with On‐line Monitoring of Conversion and Stereoselectivity
Authors: Scatena Gabriel S. , de la Torre Alexander F. , Cass Quezia B. , Rivera Daniel G. , Paixão Márcio W. 
Published: September 2014

AbstractThe derivatization of organocatalysts with functional appendages suitable to anchor onto solid supports is usually achieved by stepwise syntheses. As an alternative to such a strategy, this work describes a one‐pot approach to silylated prolyl‐peptide catalysts by a multicomponent reaction that enables the simultaneous incorporation of the catalytic and the heterogenizable (triethoxysilane) moieties. A microreactor with high catalytic efficacy and reproducibly in the conjugate addition of aldehydes to nitroolefins was obtained by grafting onto HPLC‐grade silica (10 μm) and packing into a column with a selected catalyst. A 3 D continuous‐flow system that includes the on‐line monitoring of the reaction outcome was set up. For that, the microreactor was coupled to a chromatographic column for the separation of the remaining substrates from the Michael adduct in the second dimension, followed by a chiral polysaccharide column for the analysis of conversion and stereoselectivity. This approach represents a new instrumental setup that combines the advantages of multidimensional chromatography and flow catalysis.
Niobium Peroxide‐Catalyzed Selective Epoxidation of Allylic Alcohols
Authors: Chen Chen , Zhao Xiuge , Chen Jizhong , Hua Li , Zhang Ran , Guo Li , Song Baoning , Gan Huimei , Hou Zhenshan 
Published: September 2014

AbstractModified niobium peroxides were prepared and used for catalyzing the epoxidation of allylic alcohols with hydrogen peroxide in the absence of any other solvent under ice bath conditions. Niobium peroxides modified with ionic liquid‐type 1‐dodecyl‐3‐methylimidazolium hydroxide or conventional tetradecyl trimethyl ammonium hydroxide surfactants demonstrated excellent yields (80–99 %) for the epoxidation of allylic alcohols to their epoxides even if the reaction was performed without any other solvent at 0 °C for 0.5 h. The catalyst characterization demonstrated that the surfactant molecules were anchored on the surface of the niobium catalyst by weak noncovalent interactions. Compared with niobium peroxides, the modified amphiphilic catalysts allowed easier accessibility to hydrophobic substrates and thus demonstrated high reaction rate and excellent recyclability for the epoxidation under mild conditions.
Biohydrogen for a New Generation of H2/O2 Biofuel Cells: A Sustainable Energy Perspective
Authors: de Poulpiquet Anne , Ranava David , Monsalve Karen , Giudici‐Orticoni Marie‐Thérèse , Lojou Elisabeth 
Published: September 2014

AbstractAmong sustainable alternatives to fossil fuel, proton exchange membrane fuel cells are promising devices that deliver electricity from hydrogen and oxygen, producing only water. The transformation of the fuel and oxidant however relies on rare‐metal catalysts. H2/O2 enzymatic biofuel cells thus emerge as sustainable biotechnological devices in which chemical catalysts are replaced by hydrogenases at the anode and multicopper oxidases at the cathode. This review discusses the recent breakthroughs and the limitations in all the components of H2/O2 biofuel cells: 1) Catalytic mechanisms involved in multicopper oxidases and hydrogenases, in addition to the new potential of enzymes from the biodiversity pool, which exhibit outstanding properties. 2) The molecular basis for oriented enzyme immobilization on the electrochemical interfaces as a prerequisite for a fast direct electron‐transfer rate. 3) The requirement for 3D networks to enhance current densities. 4) The production of H2 from biomass. 5) The history of H2/O2 biofuel cells and recent devices, which also highlights the remaining issues that will allow the use of such devices in low‐power applications.
Direct Catalytic Addition of Alkylnitriles to Aldehydes by Transition‐Metal/NHC Complexes
Authors: Sureshkumar Devarajulu , Ganesh Venkataraman , Kumagai Naoya , Shibasaki Masakatsu 
Published: September 2014

AbstractDirect catalytic addition of alkylnitriles to aldehydes allows for an atom‐economical access to β‐hydroxynitriles under proton transfer conditions. Direct use of alkylnitriles as pronucleophiles has been hampered due to their low acidity resulting in an inability to generate α‐cyano carbanions in a catalytic manner. A transition metal/N‐heterocyclic carbene (NHC) complex prepared from [{Rh(OMe)(cod)}2] and an imidazolium‐based carbene was identified as an effective catalyst to promote the reaction with as little as 1.25 mol % of catalyst loading. The corresponding Rh complex, derived from chiral triazolium salt, rendered the reaction enantioselective, albeit with moderate enantioselectivity.
Structure Sensitivity in the Decomposition of Ethylene Carbonate on Si Anodes
Authors: Rohrer Jochen , Kaghazchi Payam 
Published: September 2014

AbstractThe interaction of ethylene carbonate (EC) with Si surfaces is studied by density functional theory. The results show a strong structure sensitivity in the adsorption of EC on Si surfaces. While the adsorbed EC molecule readily decomposes on the Li/Si(111) surface, it does not dissociate on the Li/Si(100) and Li/Si(110) surfaces. On Si(111), the O atom at the top of EC is detached from the EC molecule and binds to the Li adatom, forming LiO molecules. The mechanism of EC decomposition is the transfer of 2.4 electrons from the surface to the EC molecule, as well as the formation of a covalent bond between the Li adatom and the EC molecule. This result shows that in lithium‐ion batteries with Si anodes, dissociation of the solvent and formation of a solid electrolyte interphase layer start as soon as the Li atoms cover the anode surface.
Magnetic Fe3O4 Nanoparticle‐Supported Phosphotungstic Acid as a Recyclable Catalyst for the Kabachnik–Fields Reaction of Isatins, Imines, and Aldehydes under Solvent‐Free Conditions
Authors: Nazish Mohd , Saravanan S. , Khan Noor‐ul H. , Kumari Prathibha , Kureshy Rukhsana I. , Abdi Sayed H. R. , Bajaj Hari C. 
Published: September 2014

AbstractMagnetic‐nanoparticle‐supported phosphotungstic acid has been used to efficiently catalyze the hydrophosphonylation reaction of isatins, imines, and aldehydes using dimethyl and diethyl phosphite as a nucleophile to give the corresponding α‐hydroxy and α‐amino phosphonates in excellent yields for a wide range of substrates. The reaction conditions were simple, green, and efficient. The catalyst was recycled up to five times with retention of its activity. Based on the NMR spectroscopy studies, a probable catalytic cycle was proposed.
Thin‐Film Silicon for Flexible Metal–Air Batteries
Authors: Garamoun Ahmed , Schubert Markus B. , Werner Jürgen H. 
Published: September 2014

AbstractDue to its high energy density, theoretical studies propose silicon as a promising candidate material for metal–air batteries. Herein, for the first time, experimental results detail the use of n‐type doped amorphous silicon and silicon carbide as fuel in Si–air batteries. Thin‐film silicon is particularly interesting for flexible and rolled batteries with high specific energies. Our Si–air batteries exhibit a specific capacity of 269 Ah kg−1 and an average cell voltage of 0.85 V at a discharge current density of 7.9 μA cm−2, corresponding to a specific energy of 229 Wh kg−1. Favorably in terms of safety, low concentrated alkaline solution serves as electrolyte. Discharging of the Si–air cells continues as long as there is silicon available for oxidation.
The First Family of Actinide Carboxyphosphinates: Two‐ and Three‐Dimensional Uranyl Coordination Polymers
Authors: Yang Weiting , Wang Hao , Tian Wan‐Guo , Li Jiyang , Sun Zhong‐Ming 
Published: September 2014

AbstractReaction of uranyl dications with (2‐carboxyethyl)(phenyl)phosphinic acid (CPPA, H2L) under hydrothermal conditions gave two layered isomers (UO2)2(L)2, namely, CPP‐U1 and CPP‐U2. Both of them feature edge‐sharing uranyl dimers as structure‐building units, which are ligated by CPP ligands in different ways, thus leading different layered arrangements. With the addition of imidazole derivatives, two three‐dimensional structures UO2(L)(dib)0.5 (CPP‐U3) and UO2(L)(bbi)0.5 (CPP‐U4) were generated, in which the similar uranyl‐phosphinate layers are connected by two different imidazole derivatives by means of the U–N connection [dib = 1,4‐di(1H‐imidazol‐1‐yl)benzene; bbi = 1,1′‐(1,4‐butanediyl)bis(imidazole)]. The syntheses, structure, as well as the IR spectra, and luminescent and photocatalytic properties of these uranyl organophosphinates are reported in this paper.
New Gold(I) Organometallic Compounds with Biological Activity in Cancer Cells
Authors: Bertrand Benoît , de Almeida Andreia , van der Burgt Evelien P. M. , Picquet Michel , Citta Anna , Folda Alessandra , Rigobello Maria Pia , Le Gendre Pierre , Bodio Ewen , Casini Angela 
Published: September 2014

AbstractInvited for the cover of this issue is the group of Angela Casini at the Department of Pharmacokinetics, Toxicology and Targeting, Groningen Research Institute of Pharmacy, The Netherlands. The cover image shows the uptake of gold N‐heterocyclic (NHC) complexes, bearing a fluorescent coumarin moiety, in cancer cells and the resulting anticancer effects.
The Legacy of Alfred Werner
Authors: Hindson Karen J. 
Published: September 2014

AbstractThis issue of EurJIC highlights coordination chemistry research 100 years after the first proposal of the structure of [Co(NH3)6]Cl3 as we know it today by Alfred Werner, which formed the foundation of Coordination Chemistry. Our Guest Editors, Debbie Crans and Ebbe Nordlander, invited selected participants of the 4th Zing Coordination Chemistry Conference held in Cancun in December 2013 to submit papers for this Cluster Issue.
Modern Coordination Chemistry 100 Years after Werner
Authors: Crans Debbie C. , Nordlander Ebbe 
Published: September 2014

AbstractAn overview of the papers in this cluster issue is presented.
“It is more than 100 years ago that Alfred Werner developed the research that led to the birth of coordination chemistry as we know it today. The consequences of this seminal work continue to evolve, documenting that not only structural and electronic effects but also perhaps, most importantly, the application of coordination chemistry remain as timely and current now as it was back then.”
The psychometric characteristics of an assessment instrument for perceived harmfulness in adolescents with musculoskeletal pain (PHODA‐youth)
Authors: Verbunt J.A. , Nijhuis A. , Vikström M. , Stevens A. , Haga N. , de Jong J. , Goossens M. 
Published: September 2014

AbstractBackgroundCognitive–behavioural models of chronic pain predict that dysfunctional assumptions about harmfulness of activities may maintain pain‐related fear and disability. To assess perceived harmfulness in adolescents, the Photograph Series of Daily Activities for youth (PHODA‐youth) was developed. Information concerning its methodological quality is currently lacking.ObjectiveTo investigate psychometric characteristics (factor structure, test–retest reliability, construct validity) and feasibility of the PHODA‐youth in adolescents with chronic musculoskeletal pain.Study designTest–retest design.Study populationAdolescents aged 13–21 years with chronic nonspecific musculoskeletal pain.MethodsParticipants filled in an electronic version of the PHODA‐youth including 89 items twice with a 4‐week interval. The instrument's factor structure was determined by a factor analysis. Construct validity was studied with criterion variables: catastrophizing (Pain Catastrophizing Scale for Children), pain intensity (visual analogue scale), depression (Children's Depression Inventory) and pain‐related disability (Functional Disability Inventory) using regression analysis. Test–retest reliability was evaluated based on the Pearson correlation coefficient. Feasibility was studied with self‐constructed questions.ResultsSeventy‐one adolescents participated. Results show a three‐factor structure for the PHODA‐youth including 51 items with subscales labelled as: ‘activities of daily life’, ‘intensive physical activities’ and ‘social activities’. Total and subscale scores showed a high internal consistency. Its test–retest reliability was good (r = 0.94) and its construct validity is supported by the finding that both catastrophizing (β = 0.25; p = 0.02) and disability (β = 0.71; p < 0.001) were uniquely related to the PHODA‐youth. In addition, feasibility appeared adequate.ConclusionThe findings support the PHODA‐youth as a valid and reliable measure of the perceived harmfulness of activities in adolescents with musculoskeletal pain.
Conversion of Calophyllum inophyllum Oil with a High Free Fatty Acid Content to Biodiesel using a Starch‐Derived Catalyst
Authors: Ayodele Olubunmi O. , Dawodu Folasegun A. 
Published: September 2014

AbstractBiodiesel was produced from Calophyllum inophyllum oil using a starch‐derived catalyst. The catalyst, obtained by the sulfonation of carbonized starch, was characterized by various techniques. The catalyst was capable of esterification and transesterification reactions under the conditions studied and it was superior to a catalyst derived from glucose. A biodiesel yield of 99.0 % was achieved under the optimized conditions. The activity of the starch‐derived catalyst can be related to its SO3H density but also to its dispersion and swelling in the reaction medium. The reaction modeled using Langmuir–Hinshelwood (LH) kinetics showed a reaction rate constant that was strongly dependent on temperature, which confirms that the reaction is favored thermodynamically by temperature. This study shows that the catalyst can find application in integrated biodiesel production processes in which both the catalyst and oil feedstock are derived from renewable sources.
Development of a list of reference chemicals for evaluating alternative methods to in vivo fish bioaccumulation tests
Authors: Rodriguez-Sanchez Neus , Cronin Mark Timothy David , Lillicrap Adam , Madden Judith Clare , Piechota Przemyslaw , Tollefsen Knut Erik 
Published: September 2014

Abstract

The aim to reduce the number of animals in experiments has highlighted the need to develop and validate nonanimal methods as alternatives to bioaccumulation studies using fish. The present study details a novel 3-tier approach to develop a list of reference compounds to aid this process. The approach was based on 1) the inclusion of relevant chemical classes supported by high-quality in vivo data for the bioconcentration factor (BCF), whole-body biotransformation rates (Kmet), and metabolism characterization for rainbow trout (Oncorhynchus mykiss) and common carp (Cyprinus carpio) (tiers I and II); and 2) the refinement to ensure a broad coverage of hydrophobicity, bioconcentration potential, molecular weight, maximum molecular diameter, whole-body biotransformation half-lives, and metabolic pathways (tier III). In silico techniques were employed to predict maximal log BCF and molecular and metabolic properties. Of the 157 compounds considered as reference compounds, 144 were supported by high-quality BCF data, 8 were supported by Kmet data, and 5 were supported by in vivo metabolism data. Additional criteria for refinement of the list of reference compounds were suggested to aid practical implementation in experimental efforts. The present list of reference compounds is anticipated to facilitate the development of alternative approaches, enhance understanding of in vivo and in vitro bioaccumulation relationships, and refine in silico BCF and metabolism predictions. Environ Toxicol Chem 2014;33:2740–2752. © 2014 SETAC
Characterization of trenbolone acetate and estradiol metabolite excretion profiles in implanted steers
Authors: Blackwell Brett R. , Brown Tyson R. , Broadway Paul R. , Buser Michael D. , Brooks J. Chance , Johnson Bradley J. , Cobb George P. , Smith Philip N. 
Published: September 2014

Abstract

Exogenous growth promoters have been used in US beef cattle production for over 50 yr. The environmental fate and transport of steroid growth promoters suggest potential for endocrine-disrupting effects among ecological receptors; however, the initial excretion of steroid metabolites from cattle administered growth promoters has not been well characterized. To better characterize excretion of trenbolone acetate and estrogen metabolites, steers were assigned to 1 of the following treatment groups: control, given no implant, or treatment, administered a combination implant (200 mg trenbolone acetate, 40 mg estradiol). Blood, urine, and fecal samples were collected over the course of 112 d following implantation. Samples were extracted and analyzed by liquid chromatography tandem mass spectrometry for trenbolone acetate and estrogen metabolites. In both urine and feces, 17α-trenbolone and 17α-estradiol were the predominant metabolites following implantation. Mean concentrations of 17α-trenbolone and 17α-estradiol in feces of implanted steers were 5.9 ± 0.37 ng/g and 2.7 ± 0.22 ng/g, respectively. A best-fit model is presented to predict 17α-trenbolone and 17α-estradiol excretion from steers receiving implants. The present study provides the first characterization of both trenbolone and estrogen metabolites in excreta from implanted cattle and will help provide estimates of steroid production from feedyards in the United States. Environ Toxicol Chem 2014;33:2850–2858. © 2014 SETAC
Particle-specific toxic effects of differently shaped zinc oxide nanoparticles to zebrafish embryos (Danio rerio)
Authors: Hua Jing , Vijver Martina G. , Richardson Michael K. , Ahmad Farooq , Peijnenburg Willie J.G.M. 
Published: September 2014

Abstract

A general approach is proposed that allows for quantifying the relative toxic contribution of ions released from metallic nanoparticles and of the particles themselves, as exemplified for the case of differently shaped zinc oxide (ZnO) nanoparticles (NPs) exposed to zebrafish embryos. First of all, the toxicity of suspensions of ZnO nanoparticles (NP(total))—nanospheres, nanosticks, cuboidal submicron particles (SMPs), and Zn(NO3)2—to the embryos was assessed. The observed toxicity of ZnO NP(total) is assumed to result from the combined effect of the particles present in the suspensions (NP(particle)) and of the dissolved Zn2+ ions released from the particles (NP(ion)). Different addition models were used to explicitly account for the toxicity of NP(particle). The median lethal concentrations (LC50) of NP(particle) of nanospheres, nanosticks, and SMPs were found to range between 7.1 mg Zn/L and 11.9 mg Zn/L (i.e., to differ by a factor of 1.7). Behavioral performance showed no significant differences among all types of the NP(particle). The median effective concentrations (EC50) of the particles were found to range between 1.0 mg Zn/L and 2.2 mg Zn/L. At the LC50 of each particle suspension, the main contribution to lethality to zebrafish embryos was from the NP(particle) (52%–72%). For hatching inhibition, the NP(particle) was responsible for 38% to 83% of the adverse effects observed. The ZnO nanosticks were more toxic than any of the other NPs with regard to the endpoints mortality and hatching inhibition. The main contribution to toxicity to zebrafish embryos was from the NP(particle) at the LC50 and EC50 of each particle suspension. Environ Toxicol Chem 2014;33:2859–2868. © 2014 SETAC
Joint allocation of uplink and downlink resources for interactive mobile cloud applications
Authors: Chen Jiadi , Zheng Kan , Long Hang , Wang Wenbo 
Published: September 2014

AbstractCloud‐based mobile applications are interactive in nature. Due to the strong correlation between uplink request and downlink response, it is irrational to optimize the uplink and downlink resource allocation problem separately and independently. In this paper, the joint uplink and downlink resource allocation problem for interactive mobile cloud applications is considered. The data exchange characteristics between mobile terminal and cloud server is investigated and a novel traffic model including both uplink and downlink transmission queues is constructed. Based on the new traffic model, the resource allocation problem can be formulated as a constrained Markov Decision Process. The objective is to minimize the application response time, that is, the roundtrip delay of causally related packet group (PG) pairs, with a constraint on PG drop rate. The Q‐learning algorithm and Value Iteration Algorithm are employed to obtain a solution that converges to the optimal one. To combat the curse of dimensionality, a sub‐optimal solution is proposed to solve the problem with an acceptable complexity. Numerical results indicate that the reduced complexity solution can achieve a delay performance approximate to that of the optimal solution and outperform other allocation schemes. Copyright © 2014 John Wiley & Sons, Ltd.
Strategies: Energy IT and Business Process Outsourcing—Key Concepts and Trends
Authors: Whitfield Milton B. 
Published: September 2014

AbstractEnergy companies have been doing information technology outsourcing (ITO) and business process outsourcing (BPO) transactions for many years. Besides reviewing some of the key benefits and risks that many energy companies have faced in their ITO and BPO deals, this article will identify some of the latest trends and, in particular, discuss the social media, mobility, analytics, and cloud computing (SMAC) revolution that is occurring across various industries.
Hospitalization for ambulatory care sensitive conditions at health insurance organization hospitals in Alexandria, Egypt
Authors: Mosallam Rasha A. , Guirguis Wafaa W. , Hassan Mona HA 
Published: September 2014

SUMMARYThis study aimed at estimating the percentage of hospital discharges and days of care accounted for by Ambulatory Care Sensitive Conditions (ACSCs) at Health Insurance Organization (HIO) hospitals in Alexandria, calculating hospitalization rates for ACSCs among HIO population and identifying determinants of hospitalization for those conditions. A sample of 8300 medical records of patients discharged from three hospitals affiliated to HIO at Alexandria was reviewed. The rate of monthly discharges for ACSCs was estimated on the basis of counting number of combined ACSCs detected in the three hospitals and the hospitals' average monthly discharges. ACSCs accounted for about one‐fifth of hospitalizations and days of care at HIO hospitals (21.8% and 20.8%, respectively). Annual hospitalization rates for ACSCs were 152.5 per 10,000 insured population. The highest rates were attributed to cellulitis/abscess (47.3 per 10,000 population), followed by diabetes complications and asthma (42.8 and 20.8 per 10,00 population). Logistic regression indicated that age, number of previous admissions, and admission department are significant predictors for hospitalization for an ACSC. Copyright © 2014 John Wiley & Sons, Ltd.