bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of 8‐hydroxyquinoline‐type composite chelating material HQ‐PHEMA/SiO2 and its adsorption behavior for heavy metal ions
Authors: Li Yanbin , Gao Baojiao , Fang Xiaolin 
Published: April 2013

AbstractBACKGROUNDAn 8‐hydroxyquinoline (HQ)‐type composite chelating material with high performance was designed and prepared. Monomer hydroxyethyl methacrylate (HEMA) was first grafted onto silica gel particles via surface‐initiated graft‐polymerization, forming grafted particles PHEMA/SiO2 with a high grafting degree. Subsequently, through the substitution reaction between 5‐chloromethyl‐8‐hydroxyquinoline (CHQ) and the grafted macromolecules PHEMA, HQ groups were bonded onto the grafted particles, obtaining the composite chelating material HQ‐PHEMA/SiO2. The chelating adsorption performance and mechanism of HQ‐PHEMA/SiO2 towards Cu2+ and Ni2+ ions was studied, and the adsorption thermodynamics was investigated.RESULTSThe experimental results show that HQ‐PHEMA/SiO2 possesses a strong adsorption affinity for heavy metal ions owing to the high density of the HQ group, and for Cu2+ and Ni2+ ions, the adsorption capacities were up to 63.4 mg g−1 and 51.1 mg g−1, respectively. The adsorption behavior fits the Langmuir model, and the adsorption enthalpy change ΔH is positive, indicating endothermic chemisorption. The value of the entropy change ΔS is also positive, and the higher value of |TΔS| suggests that the adsorption process is entropically driven.CONCLUSIONHQ‐PHEMA/SiO2 is a promising material for the effective removal of heavy metal ions from water. © 2013 Society of Chemical Industry
Recruiting hospitalized patients for research: How do participants differ from eligible nonparticipants?
Authors: Voss Rachel , Gravenstein Stefan , Baier Rosa , Butterfield Kristen , Epstein‐Lubow Gary , Shamji Hannah , Gardner Rebekah 
Published: April 2013

BACKGROUNDRandomized controlled trials provide strong evidence for guidelines and interventions. Yet, much of the eligible population declines to be studied.OBJECTIVETo identify differences between participants and eligible nonparticipants in (1) perceived stress, (2) self‐efficacy, (3) recovery expectations, (4) discussing advance directives, and (5) understanding a standard prescription label (health literacy).DESIGNQuasi‐experimental prospective cohort study in 5 acute‐care hospitals.METHODSWe approached 295 hospital inpatients as they were being recruited for a behavioral intervention and asked them to answer 5 screening questions. We matched respondents' answers to their acceptance of the behavioral intervention and to Medicare claims and enrollment data. We used multivariate logistic regression to compare consent rates based on screening‐question responses.SETTING/PATIENTSHospitalized fee‐for‐service Medicare patients.RESULTSPatients were less likely to consent to the behavioral intervention when they reported feeling unable to control important things in their lives (odds ratio [OR]: 0.35, 95% confidence interval [CI]: 0.14‐0.92), had low recovery expectations (OR: 0.17, 95% CI: 0.06‐0.45), or were confused by any question (OR: 0.11, 95% CI: 0.05‐0.24). Conversely, individuals who answered the medication question incorrectly were more likely to consent to the behavioral intervention (OR: 3.82, 95% CI: 1.12‐13.03). There were no significant differences in consent for patients who reported feeling overwhelmed or reported discussing advance care planning with family members or doctors.CONCLUSIONSHospitalized eligible nonparticipants differ in constructs related to perceived stress, recovery expectation, and health literacy. Recognizing such characteristics may inform strategies to improve intervention recruitment in the hospital and representation in clinical trials. Journal of Hospital Medicine 2013;8:208–214. © 2013 Society of Hospital Medicine
Novel GNE compound heterozygous mutations in a GNE myopathy patient
Authors: Cai Huaying , Yabe Ichiro , Shirai Shinichi , Nishimura Hiroaki , Hirotani Makoto , Kano Takahiro , Houzen Hideki , Yoshida Kazuto , Sasaki Hidenao 
Published: April 2013

ABSTRACTIntroduction: Molecular studies have revealed that some patients with myopathies with rimmed vacuoles have pathogenic mutations in the UDP‐N‐acetylglucosamine‐2‐epimerase/N‐acetylmannosamine kinase (GNE) and Z‐band alternatively spliced PDZ motif‐containing protein (ZASP) genes. Methods: We investigated a patient with distal myopathy with rimmed vacuoles by muscle biopsy and sequenced 6 candidate genes. Results: The patient carried GNE compound heterozygous missense mutations (p.V421A and p.N635K) and a ZASP variant (p.D673N). This patient also presented with distal weakness sparing the quadriceps muscles and had atypical results for Z‐band‐associated protein immunostaining. This finding indicates that the GNE mutations are pathogenic, and the diagnosis is compatible with GNE myopathy. Conclusions: By combining pathological studies and candidate gene screening, we identified a patient with GNE myopathy due to novel GNE compound heterozygous mutations. Muscle Nerve 48: 594–598, 2013
Anionic to metathesis transformation polymerisation
Authors: Amass Allan J. , Gregory Denis 
Published: April 2013

AbstractAn anionic to metathesis transformation reaction has been devised to study the mechanism of initiation of the metathesis ring‐opening polymerisation of cyclic alkenes and, by inference, the metathesis of alkenes also. The products of the reaction have been analysed by g.p.c. using a dual detector system to establish that block copolymers are formed when polystyryl lithium and tungsten hexachloride are used as initiator for the polymerisation of cyclopentene. A mechanism is proposed for the incorporation of polystyrene segments during the initiation step involving the formation of a bimetallic bridged complex that rearranges to form the active centre. There is also evidence that polystyrene segments are introduced during the termination reaction of the kinetic chain.
Thermal degradation of some polyimides
Authors: Crossland Barbara , Knight Graham J. , Wright Walter W. 
Published: April 2013

AbstractFour different polyimides have been studied by thermogravimetry to ascertain their relative thermal stabilities in both inert and oxidising atmospheres. Experiments have been carried out at a rate of temperature rise of 2°C min −1 and isothermally at a number of temperatures in order to calculate overall activation energies for breakdown. The polymers have also been examined by pyrolysis‐gas chromatography‐mass spectrometry using two different procedures. In the first, fresh samples were pyrolysed at a number of increasing temperatures, whereas in the second, the same sample was subjected to successive pyrolyses at the same temperature intervals. The results are compared with those of other workers derived using different techniques.
Reactions of initiating radicals with unsaturated derivatives of pyridine
Authors: Bevington John C. , Huckerby Thomas N. , Varma Sushil C. 
Published: April 2013

Abstract2,2′‐Azo‐bis‐isobutyronitrile (AIBN), enriched in its methyl groups with carbon‐13, has been used to initiate copolymerizations at 60°C of 2‐vinylpyridine (2VP) with methyl methacrylate (MMA). Examination by 13C n.m.r. of the end groups in the copolymers indicates that 2VP is 2–4 times as reactive as MMA towards the 2‐cyano‐2‐propyl radical. The presence of either 4‐styrylpyridine of 2,6‐distyrylpyridine in MMA or styrene causes considerable alteration of the 13C n.m.r. signals from C6H513COO—end groups in polymers prepared at 60°C using benzoyl peroxide as initiator but has no effect on the signals from (13CH3)2C(CN)— end groups derived from AIBN. It is deduced that the styrylpyridines are rather reactive towards the benzoyloxy radical but are unreactive towards the 2‐cyano‐2‐propyl radical.
Living carbocationic polymerisation. XI. Copolymerisation of isobutylene with isoprene. Initial investigations
Authors: Faust Rudolf , Fehérvåri Ægota , Kennedy Joseph P. 
Published: April 2013

AbstractThe copolymerisation of various isobutylene (IB)‐isoprene (IP) charges has been investigated by the use of the cumyl acetate‐BCl3 complex initiating system in CH3Cl or CH2Cl2 diluents at — 30°C. Conditions have been defined under which charges containing 2 0 120mol % IP lead to living copolymerizations and yield soluble (gel‐free) copolymers containing from 1 2 to 7 8 mol % 1,4‐IP units in the M̄;n = 2400−12 100 range with M̄;w/M̄;n ∼ 1 8. Conversion (rate) and M̄;n decrease with increasing IP in the charge. The reactivity ratios in this IP range are rIB = 2 4 ± 0 35 and rIP = 4 5 ± 3 0, i.e. rIBrIP = 10 8; nonetheless the copolymers are statistical because of the very low IP contents in the charge. With 20–50 mol % IP in the charge two or more contiguous IP units will be formed at the growing chain end which may lead to cyclisation. Cyclisation leads to proton elimination which ultimately results in chain transfer to monomer. A mechanism has been developed that accounts for the observations and points the way for further research.
Reactivity of cis and trans forms of ion‐pairs in the anionic polymerisation of butadiene
Authors: McDonald R. T. , Bywater S. 
Published: April 2013

Abstractcis and trans forms of n‐butylallyl potassium have been prepared by low temperature metallation of cis and trans heptene‐2. Their rates of reaction with butadiene in tetrahydrofuran have been measured as a function of temperature. The trans form is more reactive. The results are compared with the propagation rates of butadiene in tetrahydrofuran using K+ as counter‐ion.
Acid and enzymatic saccharification of agricultural mixed polymers for alcohol production
Authors: Tewari H. K. , Marwaha Satwinder S. , Singh L , Kennedy John F. 
Published: April 2013

AbstractThe paper reports the evaluation of potentials of acid (HCl and H2SO4) and enzymatically (cellulase) saccharified corncob, groundnut shell, sugarcane bagasse and wheat straw biopolymers for ethanol production. Of the three yeast isolates tested, Saccharomyces cerevisiae var. ellipsoideus was found to be most efficient, closely followed by Kluyveromyces marxianus NCYC 179 in its ability to ferment enzymatically hydrolysed mash of all the substrates tested to ethanol. However, S. cerevisiae NCYC 240 and acid hydrolysed agricultural polymers were found to be a poor organism and poor substrates, respectively, for ethanol fermentation. The order of ethanol production on substrate basis was corncob > wheat straw > sugarcane bagasse > groundnut shell biomass biopolymer. An incubation period of 24 h was found optimum for the optimal production of ethanol by S. cerevisiae var. ellipsoideus in both acid and enzymatically hydrolysed agricultural residues.
Thermal behaviour of films of partially neutralized poly(acrylic acid). 2: The influence of univalent cations
Authors: Nicholson John W. , Wilson Alan D. 
Published: April 2013

AbstractFurther studies have been carried out on the thermal behaviour of partially neutralized poly(acrylic acid), using ammonium or sodium ions as the neutralizing species. It was found that, unlike the partial poly(acrylates) of lithium, sodium or potassium, partially neutralized ammonium poly(acrylate) did not undergo thermal decarboxylation on heating to 250°C. Instead, the anhydride groups, formed by reaction of the unneutralized portions of the poly(acrylic acid) macromolecule, underwent no further reaction. On the other hand, further study of the decarboxylation of 10% neutralized sodium poly(acrylate) has shown the process to be first‐order in anhydride groups, with a rate constant of 2 23 × 10‐3 s−1 at 250×C. A mechanism consistent with the kinetic data is proposed to account for the overall sequence leading to decarboxylation.
Properties of positive resists. I. irradiation‐induced degradation and sensitivity of certain methyl methacrylate copolymers
Authors: Parsonage Edward E. , Peppas Nikolaos A. 
Published: April 2013

AbstractPoly(methyl methacrylate), poly(methyl methacrylate‐co‐2‐hydroxyethyl methacrylate), poly(methyl methacrylate‐co‐itaconic acid), poly(methyl methacrylate‐co‐maleic anhydride), poly(methacrylic acid‐co‐itaconic acid), poly(methacrylic acid‐co‐maleic anhydride), and poly(itaconic acid) were prepared by copolymerization of the appropriate amounts of the two monomers at 50°C for 24–40 h using benzoyl peroxide as initiator. Selected samples were γ‐irradiated with a total dose ranging from 2 to 12 Mrad. The unexposed and degraded polymers were dissolved in tetrahydrofuran and their molecular weight distribution was determined by gel permeation chromatography. It was found that M̄n decreased drastically with increasing irradiation dose. The presence of various functional groups in both unexposed and irradiated samples was confirmed by infrared spectroscopy. The copolymer thermodynamic compatibility with various solvents was evaluated on the basis of their fractional solubility parameters. The Gs values of these copolymers were determined using the gel permeation chromatography data. It was established that, among those studied, poly(methyl methacrylate‐co‐maleic anhydride) is the best material for positive resist application based on a Gs value of 8 9 scissions per 100eV.
Tensile strength and toughness of acetylated pine and lime flakes
Authors: Rowell Roger M. , Banks W. Bart 
Published: April 2013

AbstractThin strips of pine, Pinus sylvestris, and lime, Tilia vulgaris, were acetylated with acetic anhydride to various levels of acetyl weight gains. Increase in thickness, due to the bulking effect of acetylation, and increase in equilibrium moisture content at 65% relative humidity were determined. Equilibrium moisture content decreased as the degree of acetylation increased for both pine and lime.Finite span tensile strength was determined on thin control and acetylated pine and lime strips. No significant loss of tensile strength was found in either species due to acetylation. Total work expended in fracturing the specimens (work‐to‐failure) was slightly decreased for acetylated pine but remained essentially unchanged for acetylated lime as compared to controls. This indicates that the toughness of the material is only slightly reduced by the acetylation process.
Polymer pyrolysis: A resolution of anomalies in kinetic schemes for the rate of evolution of volatile products
Authors: Hammond Timothy , Lehrle Roy S. 
Published: April 2013

AbstractKinetic schemes proposed by three groups of workers for polymer pyrolysis have been critically examined, in order to resolve apparent anomalies, especially in the way in which the overall first‐order rate constant for volatile evolution by depropagation mechanisms, involving different modes of initiation and termination, have been interpreted. In one scheme, the treatment of rate was found to be inappropriate for changing‐volume systems, and the resulting rate expressions therefore cannot be recommended. When choice of units, conventions, and symbols was taken into account, the other schemes were found to be totally compatible. These schemes lead to identical expressions for the initial rate of evolution of a volatile product, provided the symbols are defined specifically according to the conventions chosen. These expressions are to be recommended for studies of this kind.
Polyethers for biomedical applications: Bulk and surface characterisation of crosslinked blends of poly(ethylene oxide) and poly(propylene oxide)
Authors: Bots Jan Gert , van der Does Leen , Bantjes Adriaan , Lutz Bert 
Published: April 2013

AbstractBulk and surface properties of crosslinked and non‐crosslinked blends of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPOX) were studied for the elucidation of the behaviour of these materials in contact with blood. In the crosslinked blends the hydrophilic character increased with increasing PEO content, as concluded from swelling experiments and contact angle determinations. D.s.c. and dynamic mechanical measurements indicated the occurrence of phase separation in the blends and d.s.c. showed that on equilibration with water the PEO phase loses its crystallinity. F.t.‐i.r.‐a.t.r. analysis of the surface of crosslinked PPOX‐PEO films showed an enrichment of the surface with PEO.These observations indicate that the good blood‐compatibility of PPOX‐PEO blends might be explained by the presence of an amorphous, PEO‐enriched, hydrophilic surface.
Relative performance of tracking versus fixed tilt photovoltaic systems in the USA
Authors: Drury Easan , Lopez Anthony , Denholm Paul , Margolis Robert 
Published: April 2013

ABSTRACTTracking systems can increase the amount of electricity generated by photovoltaic (PV) modules, by actively orienting each module to intercept more solar energy. We find that horizontal one‐axis tracking systems can increase PV generation by 12–25% relative to south‐facing fixed mount PV systems with 25° tilts in the contiguous USA, and two‐axis tracking systems can increase PV generation by 30–45% relative to fixed mount systems. Tracking systems increase PV generation more significantly in arid regions such as the southwest USA than in humid regions with persistent cloud cover such as the Pacific Northwest and coastal Atlantic states. We find that fixed and tracking PV systems have similar interannual variability in their generation profiles, and this variability is primarily driven by project location. Tracking PV projects cost more than fixed tilt systems, per unit capacity, and we explore how much more tracking projects could cost while generating similar levelized costs of energy as fixed tilt systems. We define this as the breakeven additional cost of tracking and find that it is primarily driven by three factors: (i) regional tracking performance, (ii) fixed tilt system costs that tracking projects compete against, and (iii) additional tracking operation and maintenance costs. Using this framework, we explore the relative competitiveness of tracking systems for a range of fixed and tracking PV prices and evaluate how tracking competitiveness varies by region. Copyright © 2013 John Wiley & Sons, Ltd.
A functional study of two dsRNA binding protein genes in Laodelphax striatellus
Authors: Lu Ding‐hao , Wu Min , Pu Jian , Feng Ai , Zhang Qian , Han Zhao‐jun 
Published: April 2013

AbstractBACKGROUNDOne of the key limiting factors for using RNA interference technology to develop new pest control practices is the toxicological effectiveness. In order to explore potential methods to improve the efficiency of RNAi in insects, we cloned two dsRNA binding proteins from Laodelphax striatellus and investigated their functions.RESULTSIn this study, the genes homologous to the dsRNA binding proteins TRBP and STAU in L. striatellus were first cloned and designated as LsTRBP and LsSTAU. Using the chitinase gene Chi, which has been confirmed to have lethal effects when knocked down by RNAi, as a reporter, the functions of these two dsRNA binding proteins were then investigated by using dsRNA feeding. The results showed that feeding with dsChi alone caused significant lethal effects, with a mortality four‐fold higher than that of the control, whereas feeding with dsTRBP or dsSTAU alone did not yield any significant lethal effects. When dsChi was fed in the mixture 1:1 with dsSTAU, it also resulted in high mortality, which was a little lower than feeding with dsChi alone, but not statistically significant. However, when fed in the 1:1 mixture with dsTRBP, the lethal effect of dsChi was completely eliminated. Further analysis of gene expression found that single dsRNA depressed only its own target gene. When treated in 1:1 mixture, dsSTAU or dsChi did not change significantly the depression of the other dsRNA, but dsTRAB counteracted almost all the effect of dsChi.CONCLUSIONThese results indicate that the loss of LsTRBP can significantly inhibit dsChi‐mediated genetic interference. These findings not only suggest that the LsTRBP gene in L. striatellus plays an important role in regulating RNAi but also imply that the metabolic regulation of dsRNAs with respect to genetic interference in L. striatellus is similar to that in higher animal species. © 2013 Society of Chemical Industry
Valence band structure engineering of thin SiGe/Si quantum wells for piezoresistive applications
Authors: Reparaz J. S. , Goñi A. R. , Alonso M. I. , Garriga M. 
Published: April 2013

AbstractIn this work, we have theoretically investigated the influence of quantum confinement, biaxial stress, and high hydrostatic pressure on the valence band structure of Si1−xGex/Si quantum wells (QW) with x ranging from 0.1 to 0.75, QW thicknesses up to 50 nm, and hydrostatic pressures up to 8 GPa. Using the Nextnano simulator, we have solved the 6 × 6 k · p Hamiltonian obtaining the valence band eigenvalues (for light‐ and heavy‐hole states) as well as their dispersion close to k = 0. We have found that for specific combinations of x, QW thickness, and hydrostatic pressure, it is possible to tailor the energy of the light‐ and heavy‐hole states in such a way that they become almost degenerate for k = 0.This results in a larger interaction between these sub‐bands leading to an electron‐like dispersion of certain hole sub‐bands. We present representative examples showing that as pressure increases from 0 to 4 GPa the dispersion type of the hole states progressively evolves from electron‐like to almost hole‐like, which naturally produces sharp peaks in their corresponding density of states at k ≠ 0. The opposite transition from hole‐like to electron‐like band dispersion is also briefly discussed. This peculiar behavior of the dispersion type of the valence sub‐bands induced by hydrostatic pressure results particularly interesting for piezoresistive applications, since large changes in the electrical conductivity are expected as a function of external stress.
Phase competition in (La1 − c,Src)CoO3 solid solutions: ab initio thermodynamic study
Authors: Fuks David , Weizman Amir , Kotomin Eugene 
Published: April 2013

AbstractStatistical thermodynamics and density functional theory (DFT) formalisms are combined to analyze the phase competition of energetically preferable phases in (La1 − c,Src)CoO3 solid solutions upon LaCoO3 doping with Sr. La/Sr sublattice in ABO3 perovskite structure is considered as immersed in the field of CoO3 units and the superstructures that are stable with respect to the formation of antiphase domains are analyzed. The concentration‐dependent energy parameters determining the relative stability of the cubic superstructures (phases) are extracted. This allows us calculations of concentration‐ and temperature dependences of the long‐range order (LRO) parameters for different phases. The temperatures of the order–disorder phase transformations for energetically stable at T = 0 K phases are obtained. It is shown that the phase corresponding to the (La0.875,Sr0.125)CoO3 composition may exist at low temperatures. Nevertheless, already at room temperature it fails in the phase competition with the disordered (La1 − c,Src)CoO3 solid solution and the phase corresponding to the (La0.75,Sr0.25)CoO3 composition and thus hardly can be observed.