bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of γ‐Irradiation on the Physicochemical Properties of LDPE/HCB and LDPE/iPP/HCB Composites
Authors: Ali Zakaria I. , Saleh Hoda H. 
Published: July 2014

ABSTRACTThe influence of γ‐irradiation dose and the concentration of hexachlorobutadiene (HCB) on the thermal and mechanical properties of low‐density polyethylene (LDPE) and LDPE/isotactic polypropylene (iPP) blends have been investigated. Gel fraction, mechanical properties, and morphological evolution of gamma‐irradiated LDPE/HCB and LDPE/iPP/HCB composites were studied. The gel content of LDPE/HCB samples increased with increasing irradiation dose from 150 to 350 kGy and then it slightly decreased at higher irradiation dose (600 kGy). On the other hand, the gel content of LDPE/iPP/HCB (100/0/3, 80/20/3, and 50/50/3 wt%) composites increased gradually with increasing irradiation dose. For LDPE/HCB composites, the tensile strength increases gradually with increasing either the irradiation dose or HCB content. The tensile strength of LDPE/iPP/HCB blend formulations increased with increasing either the irradiation dose or iPP content. The addition of iPP to the LDPE matrix increased the thermal temperature parameters of composites as well as the incorporation of the HCB agent. The thermal stability of LDPE/iPP/HCB composites is higher than that of LDPE/HCB.
Metal‐Free Dihydrogen Oxidation by a Borenium Cation: A Combined Electrochemical/Frustrated Lewis Pair Approach
Authors: Lawrence Elliot J. , Herrington Thomas J. , Ashley Andrew E. , Wildgoose Gregory G. 
Published: July 2014

AbstractIn order to use H2 as a clean source of electricity, prohibitively rare and expensive precious metal electrocatalysts, such as Pt, are often used to overcome the large oxidative voltage required to convert H2 into 2 H+ and 2 e−. Herein, we report a metal‐free approach to catalyze the oxidation of H2 by combining the ability of frustrated Lewis pairs (FLPs) to heterolytically cleave H2 with the in situ electrochemical oxidation of the resulting borohydride. The use of the NHC‐stabilized borenium cation [(IiPr2)(BC8H14)]+ (IiPr2=C3H2(NiPr)2, NHC=N‐heterocyclic carbene) as the Lewis acidic component of the FLP is shown to decrease the voltage required for H2 oxidation by 910 mV at inexpensive carbon electrodes, a significant energy saving equivalent to 175.6 kJ mol−1. The NHC–borenium Lewis acid also offers improved catalyst recyclability and chemical stability compared to B(C6F5)3, the paradigm Lewis acid originally used to pioneer our combined electrochemical/frustrated Lewis pair approach.
[HCo(CO)4]‐Catalyzed Three‐component Cycloaddition of Epoxides, Imines, and Carbon Monoxide: Facile Construction of 1,3‐Oxazinan‐4‐ones
Authors: Liu Lixia , Sun Huailin 
Published: July 2014

AbstractThe three‐component [3+2+1] cycloaddition of epoxides, imines, and carbon monoxide to produce 1,3‐oxazinan‐4‐ones has been developed by using [HCo(CO)4] as the catalyst. The reaction occurs for a wide variety of imines and epoxides, under 60 bar of CO pressure at 50 °C, to produce 1,3‐oxazinan‐4‐ones with different substitution patterns in high yields, and provides an efficient and atom‐economic route to heterocycles from simple and readily available starting materials. A plausible mechanism involves [HCo(CO)4]‐induced ring‐opening of the epoxide, followed by sequential addition of carbon monoxide and the imine, and then ring closure to form the product accompanied by regeneration of [HCo(CO)4].
Fluorescence Sensing of Amine Vapors Using a Cationic Conjugated Polymer Combined with Various Anions
Authors: Rochat Sébastien , Swager Timothy M. 
Published: July 2014

AbstractA series of conjugated cationic polymers, differentiated only by their accompanying counter‐anions, was prepared and characterized. The choice of counter‐anion (CA) was found to drastically impact the solubility of the polymers and their optical properties in solution and in the solid state. Fluorescent polymer thin films were found to be instantaneously quenched by volatile amines in the gas phase at low ppm concentrations, and a mini‐array with CAs as variable elements was found to be able to differentiate amines with good fidelity.
Influence of change in ether structure on the low temperature dielectric relaxation of some poly(ether imide)
Authors: Eastmond Geoffrey C. , Paprotny Jerzy , Pethrick Richard A. , Santamaria‐Mendia Fernan 
Published: July 2014

ABSTRACTBroad band dielectric relaxation spectra are reported on a range of polymers created by varying the ether segment in a series of poly(ether imide)s. Changes in the structure allow the effects of steric constraints on the local conformational dynamics of the polymer chain to be explored. These changes have a significant effect on the glass transition temperatures of these polymers which range from 245 to over 420°C. In contrast, the low temperature dielectric relaxation behavior of these polymers is very similar and is attributed to cooperative local oscillatory—librational motions. Changes in the stereochemistry effect the amplitude, activation energy for the relaxation process, the packing chain density, and values of the high frequency limiting permittivity, ε∞′. This latter parameter is sensitive to the extent of dipole induced dipole and π‐π electron interactions and is influenced by the packing density. The magnitude of ε∞′ is a very important parameter in determining the suitability of poly(imide)s for electrical applications. The magnitude of ε∞′ increases with the density; however, deviations from this general trend are observed when large nonpolar groups inhibit the interaction of neighboring chains. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41191.
Green Pricing in the Asia Pacific: An Idea Whose Time Has Come?
Authors: Burke Paul J. 
Published: July 2014

AbstractThis article discusses the potential benefits of an enhanced use of externality pricing schemes in the Asia Pacific. Prices on emissions and congestion could ameliorate the negative effects of underpriced resource use, be pro‐poor and improve fiscal capacities. The main implementation challenges are political and institutional. Lessons are drawn from recent experiences in environmental taxation and the removal of fossil fuel subsidies.
Chromosomal integration of hyaluronic acid synthesis (has) genes enhances the molecular weight of hyaluronan produced in Lactococcus lactis
Authors: Hmar Rothangmawi Victoria , Prasad Shashi Bala , Jayaraman Guhan , Ramachandran Kadathur B. 
Published: July 2014

AbstractMicrobial production of hyaluronic acid (HA) is an attractive substitute for extraction of this biopolymer from animal tissues. Natural producers such as Streptococcus zooepidemicus are potential pathogens; therefore, production of HA by recombinant bacteria that are generally recognized as safe (GRAS) organisms is a viable alternative that is being extensively explored. However, plasmid‐based expression systems for HA production by recombinant bacteria have the inherent disadvantage of reduced productivity because of plasmid instability. To overcome this problem, the HA synthesis genes (hasA‐hasB and hasA‐hasB‐hasC) from has‐operon of S. zooepidemicus were integrated into the chromosome of Lactococcus lactis by site‐directed, double‐homologous recombination developing strains VRJ2AB and VRJ3ABC. The chromosomal integration stabilized the genes and obviated the instability observed in plasmid‐expressed recombinant strains. The genome‐integrated strains produced higher molecular weight (3.5–4 million Dalton [MDa]) HA compared to the plasmid‐expressed strains (2 MDa). High molecular weight HA was produced when the intracellular concentration of uridine diphosphate N‐acetylglucosamine (UDP‐GlcNAc) and uridine diphosphate‐glucuronic acid (UDP‐GlcUA) was almost equal and hasA to hasB ratio was low. This work suggests an optimal approach to obtain high molecular weight HA in recombinant strains.
Size‐selective DNA separation: Recovery spectra help determine the sodium chloride (NaCl) and polyethylene glycol (PEG) concentrations required
Authors: He Zhangyong , Xu Hong , Xiong Min , Gu Hongchen 
Published: July 2014

AbstractIn the presence of sodium chloride (NaCl), DNA fragments can be size‐selectively separated by varying the final concentration of polyethylene glycol (PEG). This separation strategy in combination with the use of paramagnetic particles provides a valuable platform for achieving the desired DNA size interval, which is important in automated library preparation for high‐throughput DNA sequencing. Here, we report the establishment of recovery spectra of DNA fragments that enable the determination of suitable NaCl and PEG concentrations for size‐selective separation. Firstly, at a given NaCl concentration, the recovery equation was obtained by fitting the DNA recovery ratios versus the PEG concentrations using the logistic function to determine the required parameters. Secondly, the slope function of the recovery equation was achieved by deducing its first derivative. Therefore, the recovery spectrum can be generated using the slope function based on those parameters. According to the recovery spectra of different length DNA fragments, suitable NaCl and PEG concentrations can be determined, respectively, by calculating their resolution values and recovery ratios. The strategy was effectively applied to the size‐selective separation of 532‐, 400‐, and 307‐bp fragments at the selected reagent concentrations with recoveries of 96.9, 64.7, and 85.9%, respectively. Our method enables good predictions of NaCl and PEG concentrations for size‐selective DNA separation.
Adaptation Measures of Energy and Utility Companies to Cope with Water Scarcity Induced by Climate Change
Authors: Gasbarro Federica , Rizzi Francesco , Frey Marco 
Published: July 2014

AbstractResource‐intensive business plays a fundamental role in causing climate change through the emission of large amounts of GHGs (greenhouse gases), and, in turn, climate‐induced physical changes affect companies. The IPCC (Intergovernmental Panel on Climate Change) reports an increase in the frequency and severity of extreme weather and climate events (IPCC, 2012). Droughts represent a major challenge for energy and water businesses, in terms of both exacerbation of dry climates and increase in the number of territories that experience water shortage. On the basis of an analysis of the energy and utility companies operating in different continents, the objective of this empirical research is twofold: on the one hand, it examines how these companies perceive the changes in water availability induced by climate change (as well as the potential impacts on business); on the other hand, it analyses the corresponding measures that these companies adopt to cope with changes in hydrology and water resources driven by climate change. Data from the Carbon Disclosure Project (CDP) provide valuable information about business climate‐related responses of several of the world's largest firms. Our results show that, in the energy and water sectors, some adaptive measures are starting to be implemented to deal not only with the risks but also with the opportunities related to climate‐induced physical changes, thus leading to interesting innovation. The paper concludes that anticipated positive effects could drive energy and utility companies towards a proactive stance to achieve a competitive advantage and trigger innovative trajectories. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment
Increasing the Reaction Rate of Hydroxynitrile Lyase fromHevea brasiliensistoward Mandelonitrile by Copying Active Site Residues from an Esterase that Accepts Aromatic Esters
Authors: von Langermann Jan , Nedrud David M. , Kazlauskas Romas J. 
Published: July 2014

AbstractThe natural substrate of hydroxynitrile lyase from rubber tree (HbHNL,Hevea brasiliensis) is acetone cyanohydrin, but synthetic applications usually involve aromatic cyanohydrins such as mandelonitrile. To increase the activity ofHbHNL toward this unnatural substrate, we replaced active site residues inHbHNL with the corresponding ones from esterase SABP2 (salicylic acid binding protein 2). Although this enzyme catalyzes a different reaction (hydrolysis of esters), its natural substrate (methyl salicylate) contains an aromatic ring. Three of the eleven single‐amino‐acid‐substitution variants ofHbHNL reacted more rapidly with mandelonitrile. The best wasHbHNL‐L121Y, with akcat4.2 times higher and high enantioselectivity. Site‐saturation mutagenesis at position 121 identified three other improved variants. We hypothesize that the smaller active site orients the aromatic substrate more productively.
A General Method for Preparing Bridged Organosilanes with Pendant Functional Groups and Functional Mesoporous Organosilicas
Authors: Bürglová Kristýna , Noureddine Achraf , Hodačová Jana , Toquer Guillaume , Cattoën Xavier , Wong Chi Man Michel 
Published: July 2014

AbstractNew organosilica precursors containing two triethoxysilyl groups suitable for the organosilica material formation through the sol‐gel process were designed and synthesised. These precursors display alkyne or azide groups for attaching targeted functional groups by copper‐catalysed azide–alkyne cycloaddition (CuAAC) and can be used for the preparation of functional organosilicas following two strategies: 1) the functional group is first appended by CuAAC under anhydrous conditions, then the functional material is prepared by the sol‐gel process; 2) the precursor is first subjected to the sol‐gel process, producing porous, clickable bridged silsesquioxanes or periodic mesoporous organosilicas (PMOs), then the desired functional groups are attached by means of CuAAC. Herein, we show the feasibility of both approaches. A series of bridged bis(triethoxysilane)s with different pending organic moieties was prepared, demonstrating the compatibility of the first approach with many functional groups. In particular, we demonstrate that organic functional molecules bearing only one derivatisation site can be used to produce bridged organosilanes and bridged silsesquioxanes. In the second approach, clickable PMOs and porous bridged silsesquioxanes were prepared from the alkyne‐ or azide‐containing precursors, and thereafter, functionalised with complementary model azide‐ or alkyne‐containing molecules. These results confirmed the potential of this approach as a general methodology for preparing functional organosilicas with high loadings of functional groups. Both approaches give rise to a wide range of new functional organosilica materials.
Synthesis of Indolyldiketopiperazines with NBS
Authors: Ma Yangmin , Ren Decheng , Wu Hao , Zhang Jin , Feng Tingting , Li Yanchao 
Published: July 2014

ABSTRACTTwo series of indolyldiketopiperazines were synthesized starting from methyl 1‐substituted‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylate hydrochlorides via N‐bromo‐succinimide (NBS) as an important reagent. All eight compounds were characterized by nuclear magnetic resonance (NMR) and elemental analysis. Furthermore, the mechanisms of NBS‐reacted rearrangements are also discussed. Chirality 26:790–792, 2014. © 2014 Wiley Periodicals, Inc.
An exchangeable Kendall's tau for clustered data
Authors: Romdhani Hela , Lakhal‐Chaieb Lajmi , Rivest Louis‐Paul 
Published: July 2014

AbstractThis article introduces the exchangeable Kendall's tau as a nonparametric intraclass association measure in a clustered data frame and studies the sampling properties of an estimator of this quantity. Its asymptotic distribution is derived under a multivariate exchangeable model. Two applications of the proposed statistic are considered. The first is an estimator of the intraclass correlation coefficient for data drawn from an elliptical distribution. The asymptotic properties of this estimator are investigated under an extended random effects ANOVA model. The second is a semiparametric intraclass independence test based on the exchangeable Kendall's tau whose performance is assessed using Pitman efficiencies and a Monte Carlo study. The Canadian Journal of Statistics 42: 384–403; 2014 © 2014 Statistical Society of Canada
Cardiac Repolarization Abnormalities Among Patients With Various Stages of Chronic Kidney Disease
Authors: Sherif Khaled A. , Abo‐Salem Elsayed , Panikkath Ragesh , Nusrat Musab , Tuncel Meryem 
Published: July 2014

AbstractBackgroundPatients with chronic kidney disease (CKD) are at increased risk of life‐threatening cardiovascular arrhythmias. Although these arrhythmias are usually secondary to structural heart diseases that are commonly associated with CKD, a significant proportion of cases with sudden cardiac death have no obvious structural heart disease. This study aims to explore the relationship of cardiac repolarization in patients with CKD and worsening kidney function.HypothesisThere is cardiac repolarization abnormalities among patients with chronic kidney disease.MethodsThis was a retrospective, chart‐review study of admissions or clinic visits to a university hospital between 2005 and 2010 by patients with a diagnosis of CKD. Inclusion criteria selected patients who had 12‐lead surface electrocardiography (ECG), renal function tests within 24 hours, and transthoracic echocardiography within 6 months. Cases with a documented etiology for the corrected Qt (Qtc) interval prolongation including structural heart disease, QT prolonging drugs, or relevant disease conditions, were excluded.ResultsOur sample size was 154 ECGs. Two‐thirds of patients with CKD had QTc interval prolongation, and about 20% had a QTc interval >500 ms. QTc interval was significantly different and increased with each successive stage of CKD using the Bazett (P < 0.006) or Fridericia (P = 0.03) formula. QTc interval correlated significantly with serum creatinine (P = 0.01). These finding were independent of age, gender, potassium, and calcium concentrations.ConclusionsThe progression of CKD resulted in a significant delay of cardiac repolarization, independent of other risk factors. This effect may potentially increase the risk of sudden cardiac death, and may also increase the susceptibility of drug‐induced arrhythmia.
Outcomes Associated With Fractional Flow‐Guided Revascularization: A Meta‐analysis
Authors: Bavry Anthony A. , Elgendy Islam Y. , Petersen John W. 
Published: July 2014

AbstractBackgroundDeferral of revascularization for abnormal but nonischemic lesions is usually recommended; however, the long‐term outcome of this approach is not well known.HypothesisDeferral of nonischemic lesions will be associated with a low frequency of adverse events.MethodsA PubMed search of the MEDLINE database identified studies that reported clinical outcomes among patients who had fractional flow reserve‐guided revascularization. We further categorized studies into 2 subgroups: left main and non–left main coronary artery lesions. Baseline demographics and clinical outcome data were extracted by 3 independent reviewers. Fixed and random effects summary risk ratios were constructed using Mantel‐Haenszel and DerSimonian‐Laird models, respectively. The primary outcome was the composite of death, myocardial infarction, and revascularization.ResultsFrom 741 potential studies, 17 were included in the meta‐analysis (n = 2975 participants), 8 in the left main subgroup (n = 595) and 9 studies (n = 2380) in non–left main subgroup. In the left main subgroup, the incidence of the composite outcome was 15.3% in the no‐ischemia/deferral group vs 14.3% in the ischemia/revascularization group (risk ratio [RR] = 1.13, 95% confidence interval [CI]: 0.76‐1.68, P = 0.54, I2 = 3.7%). In the non–left main subgroup, the incidence of the composite outcome was 9.2% in the no‐ischemia/deferral group vs 18.8% in the ischemia/revascularization group (RR = 0.42, 95% CI: 0.34‐0.52, P < 0.0001, I2 = 20.7%).ConclusionsPatients with left main coronary disease had a relatively high incidence of adverse cardiovascular events, which was similar in both the deferral and revascularization groups. In patients with non–left main disease, ischemia was associated with worse outcomes despite revascularization.
Effect of the Cationic Surfactant Moiety on the Structure of Water Entrapped in Two Catanionic Reverse Micelles Created from Ionic Liquid‐Like Surfactants
Authors: Villa Cristian C. , Silber Juana J. , Correa N. Mariano , Falcone R. Darío 
Published: July 2014

AbstractThe behavior of water entrapped in reverse micelles (RMs) formed by two catanionic ionic liquid‐like surfactants, benzyl‐n‐hexadecyldimethylammonium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT‐BHD) and cetyltrimethylammonium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT‐CTA), was investigated by using dynamic (DLS) and static (SLS) light scattering, FTIR, and 1H NMR spectroscopy techniques. To the best of our knowledge, this is the first report in which AOT‐CTA has been used to create RMs and encapsulate water. DLS and SLS results revealed the formation of RMs in benzene and the interaction of water with the RM interface. From FTIR and 1H NMR spectroscopy data, a difference in the magnitude of the water–catanionic surfactant interaction at the interface is observed. For the AOT‐BHD RMs, a strong water–surfactant interaction can be invoked whereas for AOT‐CTA this interaction seems to be weaker. Consequently, more water molecules interact with the interface in AOT‐BHD RMs with a completely disrupted hydrogen‐bond network, than in AOT‐CTA RMs in which the water structure is partially preserved. We suggest that the benzyl group present in the BHD+ moiety in AOT‐BHD is responsible for the behavior of the catanionic interface in comparison with the interface created in AOT‐CTA. These results show that a simple change in the cationic component in the catanionic surfactant promotes remarkable changes in the RMs interface with interesting consequences, in particular when using the systems as nanoreactors.
Working on the Edge: Stresses and Rewards of Work in a Front‐line Mental Health Service
Authors: Bowden Gillian Elaine , Smith Joanna Christina Elizabeth , Parker Pamela Anne , Boxall Matthew James Christian 
Published: July 2014

This study sought to investigate frontline mental health professionals' perceptions of work stress and the rewards and demands associated with their work. Locally known as ‘linkworkers’, and from a variety of professional backgrounds, these staff worked mainly in general practice settings. Individual interviews were conducted with nine linkworkers, and the interview transcripts were analysed thematically. The main themes identified were the following: demands, coping, individual resilience, ownership and creativity, boundaries, secure base and service philosophy and ethos. Themes, categories and sub categories were presented and discussed with seven of the linkworkers in two focus groups. Focus group transcripts were analysed, and additional themes of recognizing limitations, disillusionment and the dilemma of setting boundaries were identified. These themes overlapped with those previously identified but were associated with service changes over time. The themes of ownership and creativity and service philosophy and ethos are significant, not only in relation to their impact on individual linkworkers but also in terms of their relevance for establishing and maintaining morale, engagement and a reflective culture within a service. The relevance of this work to accessible and newly developing mental health services is considered. Copyright © 2014 John Wiley & Sons, Ltd.Key Practitioner Message

Supporting and listening to staff and allowing time for informal contact are valued by staff and enable the provision of empathic, compassionate services.
Without space for reflection, staff groups may be vulnerable to the development and effects of unhelpful organizational defences, which reduce the effectiveness, quality and efficiency of caring services and increase perceived workplace stress.
Services which foster staff engagement, ownership and creativity and employ “bottom up” approaches to service development are valued by staff and appear to increase staff morale and capacity to cope adaptively to change.