bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanocomposites based on thermoplastic polyurethane, millable polyurethane and organoclay: Effect of matrix composition and dynamic vulcanization
Authors: Barick Aruna Kumar , Chang Young‐Wook 
Published: July 2013

ABSTRACTDynamically vulcanized thermoplastic polyurethane (TPU)/millable polyurethane (MPU) blend nanocomposites, simple TPU/MPU blend nanocomposite, and TPU nanocomposite with 3 parts per hundred (phr) of organoclay were melt compounded in an internal mixer. Interfacial interactions between the organoclay and polyurethanes were examined by Fourier transform infrared spectroscopy, X‐ray diffraction, and transmission electron microscope analysis, which revealed that the dispersion of organoclays significantly improved with increasing TPU content in the TPU/MPU blends and dynamic vulcanization process. Tensile test and dynamic mechanical analysis showed that the mechanical properties are improved with the TPU content in the TPU/MPU blends and dynamic vulcanization process. Both hardness and tension set of the samples decreased with increasing MPU content in the TPU/MPU blends. Thermal stability determined by thermo‐gravimetric analysis revealed that it increased with increase in TPU concentration in the samples. Differential scanning calorimetry study showed that the glass transition temperature (Tg), melting temperature (Tm), and melt crystallization temperature (Tc) of the samples were significantly affected by the blend composition and dynamic vulcanization. Dynamic melt rheology of the nanocomposite samples in the molten state revealed a pseudo solid‐like behavior as well as an enhanced shear thinning behavior, and the variation of the rheological properties are well correlated with blend compositions and morphology of the nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4014–4023, 2013
Study on polybenzoxazinone membrane in pervaporation processes
Authors: Pulyalina Alexandra , Polotskaya Galina , Goikhman Mikhail , Podeshvo Irina , Kalyuzhnaya Ludmila , Chislov Mikhail , Toikka Alexander 
Published: July 2013

ABSTRACTPoly(benz‐3,1‐oxazinone‐4) was prepared by thermal cyclization of its hydrolytically stable precursor polyamic acid. Both polymer and its precursor were investigated as membrane materials. Thermogravimetric analysis and contact angle measurements were carried out for characterization of peculiarity of membrane compositions and analysis of membrane surface. Pervaporation of water–isopropanol mixture was studied in the wide range of feed composition. To interpret the pervaporation transport properties of the membranes, swelling experiments were performed, kinetic curves of sorption and desorption were plotted, and basic sorption and diffusion parameters were analyzed. It was established that poly(benz‐3,1‐oxazinone‐4) membrane is extremely effective in dehydration of water–isopropanol mixture and shows high separation factor. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4024–4031, 2013
Synthesis and evaluation of P(AM‐b‐DADMAC) as fixative for dissolved and colloidal substances
Authors: Wang Lijun , Li Guodong , Zhang Yiqian , Xiao He 
Published: July 2013

ABSTRACTAcrylamide (AM) and diallyldimethyl ammonium chloride (DADMAC) block copolymer P(AM‐b‐DADMAC) was synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization method. The successful polymerization of controlled composition and polydispersity index of the block copolymer was confirmed by FTIR, 1H‐NMR, and size exclusion chromatography analyses. Differential scanning calorimetry and thermal gravimetric analysis further confirmed the interaction between the trithioester groups of RAFT agent and alkenyl groups of AM and DADMAC in the final product. With turbidity, chemical oxygen demand and focused beam reflectance measurement measurements, the block copolymer was proved to be effective at fixing dissolved and colloidal substances onto papermaking fibers, thus removing these substances from the water phase where they have a tendency to aggregate and form troublesome deposits. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4040–4046, 2013
Facile preparation of shape memory polyurethanes by polyurethanes blending
Authors: Yang Shixing , Yuan Hongmin , Luo Jieling , Chen Shaojun , Ge Zaochuan , Chen Shiguo , Zheng Jiawei 
Published: July 2013

ABSTRACTThis article presents a facile preparation method of shape memory polyurethane (SMPU) by polyurethane blending from commercial thermoplastic polyurethane (PUA) with designed polyurethane (PUB). Structure, morphology, and shape memory behaviors of SMPU blends are investigated systematically. The results show that the PUB and PUA are miscible in the SMPU blends. When the PUB content is higher than 40 wt %, the Tg of SMPU blends is adjusted to above room temperature. As the PUA content increases, the PUA phase changes gradually from a droplet‐like dispersion phase to continuous soft phase, whereas the PUB phase changes from a continuous hard phase to a droplet‐like dispersion hard phase. SMPU blends show good shape memory effect when the PUA is blended with more than 40 wt % PUB. Thus, the commercialization of SMPU can be promoted greatly through the polyurethane blending from the commercial thermoplastic polyurethanes with polyurethane containing higher hard segment content. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4047–4053, 2013
Conjugated Polyelectrolytes with Aggregation‐Enhanced Emission Characteristics: Synthesis and their Biological Applications
Authors: Hu Rongrong , Ye Ruquan , Lam Jacky W. Y. , Li Min , Leung Chris W. T. , Zhong Tang Ben 
Published: July 2013

AbstractConjugated polyelectrolytes are promising candidates for the construction of fluorescent bioprobes. In this study, a series of water‐soluble fluorescent polyelectrolytes have been designed and synthesized by means of the quaternization of their tetraphenylethene‐containing polyyne precursors. The polyynes can be facilely prepared through Hay–Glaser polycoupling in high yields (up to 99 %) with high molecular weights (up to 38 900). All the polymers exhibit a phenomenon of aggregation‐induced or ‐enhanced emission. The fluorimetric titrations of biomolecules such as heparin, calf thymus DNA, RNA, bovine serum albumin, and human serum albumin to buffer solutions of the polyelectrolytes suggest that they are promising fluorescent bioprobes with high sensitivity and fast response. The emission intensity of the polyelectrolytes is enhanced by up to sevenfold upon binding with biomolecules through electrostatic and hydrophobic cooperative interactions. The polyelectrolytes can also serve as fluorescent visualizers for intracellular imaging with good biocompatibility and low autofluorescence interference.
Systems‐wide analysis and engineering of metabolic pathway fluxes in bio‐succinate producing Basfia succiniciproducens
Authors: Becker Judith , Reinefeld Jasper , Stellmacher René , Schäfer Rudolf , Lange Anna , Meyer Hanna , Lalk Michael , Zelder Oskar , von Abendroth Gregory , Schröder Hartwig , Haefner Stefan , Wittmann Christoph 
Published: July 2013

ABSTRACTBasfia succiniciproducens has been recently isolated as novel producer for succinate, an important platform chemical. In batch culture, the wild type exhibited a high natural yield of 0.75 mol succinate (mol glucose)−1. Systems‐wide 13C metabolic flux analysis identified undesired fluxes through pyruvate‐formate lyase (PflD) and lactate dehydrogenase (LdhA). The double deletion strain B. succiniciproducens ΔldhA ΔpflD revealed a 45% improved product yield of 1.08 mol mol−1. In addition, metabolic flux analysis unraveled the parallel in vivo activity of the oxidative and reductive branch of the TCA cycle in B. succiniciproducens, whereby the oxidative part mainly served for anabolism. The wild type re‐directed surplus NADH via a cycle involving malic enzyme or via transhydrogenase, respectively, to supply NADPH for anabolism, because the fluxes through the oxidative PPP and isocitrate dehydrogenase, that also provide this cofactor, were not sufficient. This was not observed for the deletion mutants, B. succiniciproducens ΔpflD and ΔldhA ΔpflD, where PPP and isocitrate dehydrogenase flux alone matched with the reduced anabolic NADPH demand. The integration of the production performance into the theoretical flux space, computed by elementary flux mode analysis, revealed that B. succiniciproducens ΔldhA ΔpflD reached 62% of the theoretical maximum yield. Biotechnol. Bioeng. 2013;110: 3013–3023. © 2013 Wiley Periodicals, Inc.
Randomized clinical trial of stents versus angioplasty for the treatment of iliac artery occlusions (STAG trial)
Authors: Goode S D , Cleveland T J , Gaines P A 
Published: July 2013

Abstract

Background
The management of total iliac artery occlusion is now undertaken routinely using percutaneous techniques but there are no controlled data to indicate whether either balloon angioplasty or stent placement is preferable. This was a multicentre randomized trial to assess whether stents confer any safety or efficacy advantage over balloon angioplasty for complete iliac artery occlusion.

Methods
Six participating centres recruited patients with symptoms of lower limb peripheral arterial disease due to iliac artery occlusion 8 cm or less in length. Patients were assigned randomly to either percutaneous transluminal angioplasty (PTA group) or primary stent placement (stent group) alone after the lesion had been traversed with a guidewire.

Results
There were 118 patients recruited to the study; six were excluded from the analysis owing to major protocol violations, leaving a total of 112 patients for analysis. Some 55 patients had PTA and 57 had a primary iliac stent. Technical success was achieved in 46 patients (84 per cent) in the PTA group and 56 (98 per cent) in the stent group (P = 0·007). There were 11 (20 per cent) major procedural complications after PTA compared with three (5 per cent) after primary stenting (P = 0·010). There were no significant differences in primary or secondary patency between the groups after 1 and 2 years.

Conclusion
Primary stent placement for iliac artery occlusion increased technical success and reduced major procedural complications (predominantly distal embolization) compared with balloon angioplasty. Registration number: ISRCTN 48145465 (http://www.controlled-trials.com).
Long-term clinical effectiveness of supervised exercise therapy versus endovascular revascularization for intermittent claudication from a randomized clinical trial
Authors: Fakhry F , Rouwet E V , den Hoed P T , Hunink M G M , Spronk S 
Published: July 2013

Abstract

Background
Long-term comparisons of supervised exercise therapy (SET) and endovascular revascularization (ER) for patients with intermittent claudication are scarce. The long-term clinical effectiveness of SET and ER was assessed in patients from a randomized trial.

Methods
Consenting patients with intermittent claudication were assigned randomly to either SET or ER. Outcome measures on functional performance (pain-free and maximum walking distance, ankle : brachial pressure index), quality of life (QoL) and number of secondary interventions were measured at baseline and after approximately 7 years of follow-up. Repeated-measurement and Kaplan–Meier methods were used to analyse the data on an intention-to treat-basis.

Results
A total of 151 patients were randomized initially to either SET or ER. After 7 years, functional performance (P &lt; 0·001) and QoL (P ≤ 0·005) had improved after both SET and ER. Long-term comparison showed no differences between the two treatments, except in the secondary intervention rate, which was significantly higher after SET (P = 0·001). Nevertheless, the total number of endovascular and surgical interventions (primary and secondary) remained higher after ER (P &lt; 0·001).

Conclusion
In the longer term, SET-first or ER-first treatment strategies were equally effective in improving functional performance and QoL in patients with intermittent claudication. The substantially higher number of invasive interventions in the ER-first group supports a SET-first treatment strategy for intermittent claudication. Registration number: NTR199 (http://www.trialregister.nl).
Sulfur‐Bridged BODIPY DYEmers
Authors: Ahrens Johannes , Böker Birte , Brandhorst Kai , Funk Markus , Bröring Martin 
Published: July 2013

AbstractReactions of BODIPY monomers with sulfur nucleophiles and electrophiles result in the formation of new BODIPY dimers. Mono‐ and disulfur bridges are established, and the new dyestuff molecules were studied with respect to their structural, optical, and electrochemical properties. X‐ray diffraction analyses reveal individual angulated orientations of the BODIPY subunits in all cases. DFT calculations provide solution conformers of the DYEmers which deviate in a specific manner from the crystallographic results. Clear exciton‐like splittings are observed in the absorption spectra, with maxima at up to 628 nm, in combination with the expected weak fluorescence in polar solvents. A strong communication between the BODIPY subunits was detected by cyclic voltammetry, where two separated one‐electron oxidation and reduction waves with peak‐to‐peak potential differences of 120–400 mV are observed. The qualitative applicability of the exciton model by Kasha for the interpretation of the absorption spectral shape with respect to the conformational state, subunit orientation and distance, and conjugation through the different sulfur bridges, is discussed in detail for the new BODIPY derivatives. This work is part of our concept of DYEmers, where the covalent oligomerisation of BODIPY‐type dye molecules with close distances is leading to new functional dyes with predictable properties.
cine‐Substitution Reactions of Metallabenzenes: An Experimental and Computational Study
Authors: Wang Tongdao , Zhang Hong , Han Feifei , Long Lipeng , Lin Zhenyang , Xia Haiping 
Published: July 2013

AbstractAlkali‐resistant osmabenzene [(SCN)2(PPh3)2Os{CHC(PPh3)CHCICH}] (2) can undergo nucleophilic aromatic substitution with MeOH or EtOH to give cine‐substitution products [(SCN)2(PPh3)2Os{CHC(PPh3)CHCHCR}] (R=OMe (3), OEt(4)) in the presence of strong alkali. However, the reactions of compound 2 with various amines, such as n‐butylamine and aniline, afford five‐membered ring species, [(SCN)2(PPh3)2Os{CHC(PPh3)CHC(CHNHR′)}] (R′=nBu(8), Ph(9)), in addition to the desired cine‐substitution products, [(SCN)2(PPh3)2Os{CHC(PPh3)CHCHC(NHR′)}] (R′=nBu(6), Ph(7)), under similar reaction conditions. The mechanisms of these reactions have been investigated in detail with the aid of isotopic labeling experiments and density functional theory (DFT) calculations. The results reveal that the cine‐substitution reactions occur through nucleophilic addition, dissociation of the leaving group, protonation, and deprotonation steps, which resemble the classical “addition‐of‐nucleophile, ring‐opening, ring‐closure” (ANRORC) mechanism. DFT calculations suggest that, in the reaction with MeOH, the formation of a five‐membered metallacycle species is both kinetically and thermodynamically less favorable, which is consistent with the experimental results that only the cine‐substitution product is observed. For the analogous reaction with n‐butylamine, the pathway for the formation of the cine‐substitution product is kinetically less favorable than the pathway for the formation of a five‐membered ring species, but is much more thermodynamically favorable, again consistent with the experimental conversion of compound 8 into compound 6, which is observed in an in situ NMR experiment with an isolated pure sample of 8.
Bond‐Forming Reactions of Small Triply Charged Cations with Neutral Molecules
Authors: Fletcher James D. , Parkes Michael A. , Price Stephen D. 
Published: July 2013

AbstractTime‐of‐flight mass spectrometry reveals that atomic and small molecular triply charged cations exhibit extensive bond‐forming chemistry, following gas‐phase collisions with neutral molecules. These experiments show that at collision energies of a few eV, I3+ reacts with a variety of small molecules to generate molecular monocations and molecular dications containing iodine. Xe3+ and CS23+ react in a similar manner to I3+, undergoing bond‐forming reactions with neutrals. A simple model, involving relative product energetics and electrostatic interaction potentials, is used to account for the observed reactivity.
Comparative anatomy of the prosubiculum, subiculum, presubiculum, postsubiculum, and parasubiculum in human, monkey, and rodent
Authors: Ding Song‐Lin 
Published: July 2013

ABSTRACTThe subicular complex, including the prosubiculum (ProS), subiculum (Sub), presubiculum, postsubiculum (PoS), and parasubiculum (PaS), plays important roles in the medial temporal memory system and is heavily involved in many neurological diseases such as Alzheimer's disease and epilepsy. In the literature, the ProS (in primate) and PoS (in rodent) are inconstantly identified, making data comparison difficult across species. This review is an attempt to discuss equivalencies and extent of the five subicular components in human, monkey, and rodent based on available information on their cytoarchitecture, chemoarchitecture, molecular signature, and neural connectivity. All five subicular cortices exist in human, monkey, and rodent. In human and monkey, the ProS and Sub extend into the uncal region anteriorly, and the PoS and PaS reach the cingulate isthmus posteriorly. In rodent, most of the typical subicular cortices are located in the dorsal and caudal portions of the hippocampal formation, and the modified version of the ventral ProS and Sub corresponds to the modified description of the uncal ProS and Sub in monkey and human. An interesting triangular region in rodent located at the juncture of the PoS, PaS, retrosplenial cortex, and visual cortex appears to be the equivalent of the monkey area prostriata. Major connections of the five subicular cortices are also summarized based on unified criteria discussed in this review, with distinct connections revealed between the ProS and the Sub. J. Comp. Neurol. 521:4145–4162, 2013. © 2013 Wiley Periodicals, Inc.
In vivo parahippocampal white matter pathology as a biomarker of disease progression to Alzheimer's disease
Authors: Solodkin Ana , Chen E. Elinor , Van Hoesen Gary W. , Heimer Lennart , Shereen Ahmed , Kruggel Frithjof , Mastrianni James 
Published: July 2013

ABSTRACTNoninvasive diagnostic tests for Alzheimer's disease (AD) are limited. Postmortem diagnosis is based on density and distribution of neurofibrillary tangles (NFTs) and amyloid‐rich neuritic plaques. In preclinical stages of AD, the cells of origin for the perforant pathway within the entorhinal cortex are among the first to display NFTs, indicating its compromise in early stages of AD. We used diffusion tensor imaging (DTI) to assess the integrity of the parahippocampal white matter in mild cognitive impairment (MCI) and AD, as a first step in developing a noninvasive tool for early diagnosis. Subjects with AD (N = 9), MCI (N = 8), or no cognitive impairment (NCI; N = 20) underwent DTI‐MRI. Fractional anisotropy (FA) and mean (MD) and radial (RD) diffusivity measured from the parahippocampal white matter in AD and NCI subjects differed greatly. Discriminant analysis in the MCI cases assigned statistical membership of 38% of MCI subjects to the AD group. Preliminary data 1 year later showed that all MCI cases assigned to the AD group either met the diagnostic criteria for probable AD or showed significant cognitive decline. Voxelwise analysis in the parahippocampal white matter revealed a progressive change in the DTI patterns in MCI and AD subjects: whereas converted MCI cases showed structural changes restricted to the anterior portions of this region, in AD the pathology was generalized along the entire anterior–posterior axis. The use of DTI for in vivo assessment of the parahippocampal white matter may be useful for identifying individuals with MCI at highest risk for conversion to AD and for assessing disease progression. J. Comp. Neurol. 521:4300–4317, 2013. © 2013 Wiley Periodicals, Inc.
Oxyluciferin Photoacidity: The Missing Element for Solving the Keto–Enol Mystery?
Authors: Pinto da Silva Luís , Simkovitch Ron , Huppert Dan , Esteves da Silva Joaquim C. G. 
Published: July 2013

AbstractThe oxyluciferin family of fluorophores has been receiving much attention from the research community and several systematic studies have been performed in order to gain more insight regarding their photophysical properties and photoprotolytic cycles. In this minireview, we summarize the knowledge obtained so far and define several possible lines for future research. More importantly, we analyze the impact of the discoveries on the firefly bioluminescence phenomenon made so far and explain how they re‐open again the discussion regarding the identity (keto or enol species) of the bioluminophore.
Photo‐generated Carrier Dynamics in the Vicinity of the Donor/Acceptor Interface of Organic Solar Cells
Authors: Ryuzaki Sou , Onoe Jun 
Published: July 2013

SUMMARYChange in electronic states before and after photo‐irradiation at a Donor/Acceptor (D/A) interface in organic solar cells consisting of zinc‐porphyrin and fullerene films has been examined using in situ impedance spectroscopy (IS), which makes it possible to non‐destructively measure a built‐in potential (Vbi) of both D and A films at the D/A interface. The accumulation of photo‐generated carriers in the vicinity of the D/A interface was found to increase the Vbi of both D [Zn(OEP)] and A [C60] films at the interface. In addition, it was noted that the sum of Vbi obtained on photo‐irradiation was in good agreement with the open‐circuit voltage (VOC), of which the origin is still unsolved for organic solar cells. Thus, the charge accumulation of photo‐generated carriers in the vicinity of the D/A interface plays a key role in determining VOC. © 2013 Wiley Periodicals, Inc. Electron Comm Jpn, 96(8): 1–8, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11542
Analysis of satellite remote sensing observations of low ozone events in the tropical upper troposphere and links with convection
Authors: Cooper Matthew J. , Martin Randall V. , Livesey Nathaniel J. , Degenstein Doug A. , Walker Kaley A. 
Published: July 2013

AbstractSatellite observations from three instruments (Microwave Limb Sounder, Optical Spectrograph and Infrared Imaging System, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer) reveal coherent patterns of low ozone events (<20 ppb) in the tropical upper troposphere. Using a chemical transport model (GEOS‐Chem), we find that these events result from deep convective processes that rapidly transport air with low ozone concentrations from the marine boundary layer. These events occur with greater frequency over the tropical South Pacific warm pool, which is consistent with ozonesonde observations. The satellite observations indicate spatial shifts in the frequency of low ozone events that we attribute to changes in convection. As the location of the warm pool shifts eastward during El Niño events, the location of the most frequent low ozone events in the satellite record follows. Mapping of low ozone events over time reveals eastward propagating systems resembling the Madden‐Julian Oscillation. These observations and analyses strengthen the link between deep convection and ozone concentrations in the tropical upper troposphere.