bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel magnetic resonance imaging approach to collateral flow imaging in ischemic stroke
Authors: Kim Suk Jae , Son Jeong Pyo , Ryoo Sookyung , Lee Mi‐Ji , Cha Jihoon , Kim Keon Ha , Kim Gyeong‐Moon , Chung Chin‐Sang , Lee Kwang Ho , Jeon Pyoung , Bang Oh Young 
Published: July 2014

ObjectiveDedicated magnetic resonance (MR) imaging (MRI) sequences for evaluation of collaterals can be generated using MR perfusion (MRP) source data. We compared a novel collateral flow imaging technique with digital subtraction angiography (DSA) for determining collateral circulation in acute stroke and evaluated the ability of MR‐based collateral flow maps to predict outcomes after recanalization therapy.MethodsConsecutive patients who were candidates for endovascular treatment were enrolled. A collateral flow map derived from MRP source data was generated by manual or automatic postprocessing. Collateral grading based on the collateral flow map was performed and compared with grading based on DSA. Clinical and radiological outcomes were evaluated according to MR‐based collateral grading and early reperfusion (ER) status.ResultsThere was good correlation between MRI‐based and DSA‐based collateral grades (weighted κ‐coefficient = 0.70). Collateral status and achievement of ER were the 2 main determinants of a favorable functional outcome and neurological improvement, in addition to infarct growth. Regardless of achievement of ER, better collaterals were significantly associated with a lower modified Rankin score at day 90 (p < 0.001 for trend in both ER− and ER+). Most symptomatic intracranial hemorrhages occurred in patients with a poor collateral grade and ER+, whereas no patient with excellent collaterals suffered symptomatic intracranial hemorrhage or died.InterpretationMRI techniques to assess collaterals are rapidly being developed, and may provide insight into collateral perfusion. The combination of collateral images derived from pretreatment MRP source data and reperfusion status is a robust predictor of outcomes in acute ischemic stroke. Ann Neurol 2014;76:356–369
Collisional and Coulombic Unfolding of Gas‐Phase Proteins: High Correlation to Their Domain Structures in Solution
Authors: Zhong Yueyang , Han Linjie , Ruotolo Brandon T. 
Published: July 2014

AbstractThe three‐dimensional structures adopted by proteins are predicated by their many biological functions. Mass spectrometry has played a rapidly expanding role in protein structure discovery, enabling the generation of models for both proteins and their higher‐order assemblies. While important coursed‐grained insights have been generated, relatively few examples exist where mass spectrometry has been successfully applied to the characterization of protein tertiary structure. Here, we demonstrate that gas‐phase unfolding can be used to determine the number of autonomously folded domains within monomeric proteins. Our ion mobility‐mass spectrometry data highlight a strong, positive correlation between the number of protein unfolding transitions observed in the gas phase and the number of known domains within a group of sixteen proteins ranging from 8–78 kDa. This correlation and its potential uses for structural biology is discussed.
Highly Ordered Mesoporous Tungsten Oxides with a Large Pore Size and Crystalline Framework for H2S Sensing
Authors: Li Yuhui , Luo Wei , Qin Nan , Dong Junping , Wei Jing , Li Wei , Feng Shanshan , Chen Junchen , Xu Jiaqiang , Elzatahry Ahmed A. , Es‐Saheb Mahir H. , Deng Yonghui , Zhao Dongyuan 
Published: July 2014

AbstractAn ordered mesoporous WO3 material with a highly crystalline framework was synthesized by using amphiphilic poly(ethylene oxide)‐b‐polystyrene (PEO‐b‐PS) diblock copolymers as a structure‐directing agent through a solvent‐evaporation‐induced self‐assembly method combined with a simple template‐carbonization strategy. The obtained mesoporous WO3 materials have a large uniform mesopore size (ca. 10.9 nm) and a high surface area (ca. 121 m2 g−1). The mesoporous WO3‐based H2S gas sensor shows an excellent performance for H2S sensing at low concentration (0.25 ppm) with fast response (2 s) and recovery (38 s). The high mesoporosity and continuous crystalline framework are responsible for the excellent performance in H2S sensing.
“Raft” Formation by Two‐Dimensional Self‐Assembly of Block Copolymer Rod Micelles in Aqueous Solution
Authors: Rizis Georgios , van de Ven Theo G. M. , Eisenberg Adi 
Published: July 2014

AbstractBlock copolymers can form a broad range of self‐assembled aggregates. In solution, planar assemblies usually form closed structures such as vesicles; thus, free‐standing sheet formation can be challenging. While most polymer single crystals are planar, their growth usually occurs by uptake of individual chains. Here we report a novel lamella formation mechanism: core‐crystalline spherical micelles link up to form rods in solution, which then associate to yield planar arrays. For the system of poly(ethylene oxide)‐block‐polycaprolactone in water, co‐assembly with homopolycaprolactone can induce a series of morphological changes that yield either rods or lamellae. The underlying lamella formation mechanism was elucidated by electron microscopy, while light scattering was used to probe the kinetics. The hierarchical growth of lamellae from one‐dimensional rod subunits, which had been formed from spherical assemblies, is novel and controllable in terms of product size and aspect ratio.
Copper‐Catalyzed Borylative Allyl–Allyl Coupling Reaction
Authors: Semba Kazuhiko , Bessho Naoto , Fujihara Tetsuaki , Terao Jun , Tsuji Yasushi 
Published: July 2014

AbstractBorylative allyl–allyl coupling using allenes, bis(pinacolato)diboron, and allyl phosphates has been developed in the presence of a copper catalyst bearing an N‐heterocyclic carbene ligand. The reaction affords boryl‐substituted 1,5‐diene derivatives in good to high yields with high regioselectivity and Z selectivity.
Femtosecond Excitonic Relaxation Dynamics of Perovskite on Mesoporous Films of Al2O3 and NiO Nanoparticles
Authors: Hsu Hung‐Yu , Wang Chi‐Yung , Fathi Amir , Shiu Jia‐Wei , Chung Chih‐Chun , Shen Po‐Shen , Guo Tzung‐Fang , Chen Peter , Lee Yuan‐Pern , Diau Eric Wei‐Guang 
Published: July 2014

AbstractThe excitonic relaxation dynamics of perovskite adsorbed on mesoporous thin films of Al2O3 and NiO upon excitation at 450 nm were investigated with femtosecond optical gating of photoluminescence (PL) via up‐conversion. The temporal profiles of emission observed in spectral region 670–810 nm were described satisfactorily with a composite consecutive kinetic model and three transient components representing one hot and two cold excitonic relaxations. All observed relaxation dynamics depend on the emission wavelength, showing a systematic time–amplitude correlation for all three components. When the NiO film was employed, we observed an extent of relaxation proceeding through the non‐emissive surface state larger than through the direct electronic relaxation channel, which quenches the PL intensity more effectively than on the Al2O3 film. We conclude that perovskite is an effective hole carrier in a p‐type electrode for NiO‐based perovskite solar cells showing great performance.
1,3‐Dehydro‐o‐Carborane: Generation and Reaction with Arenes
Authors: Zhao Da , Zhang Jiji , Xie Zuowei 
Published: July 2014

AbstractLike the importance of benzyne, witnessed in modern arene chemistry for decades, 1,2‐dehydro‐o‐carborane (o‐carboryne), a three‐dimensional relative of benzyne, has been used as a synthon for generating a wide range of cage, carbon‐functionalized carboranes over the past 20 years. However, the selective B functionalization of the cage still represents a challenging task. Disclosed herein is the first example of 1,3‐dehydro‐o‐carborane featuring a cage CB bond having multiple bonding characters, and is successfully generated by treatment of 3‐diazonium‐o‐carborane tetrafluoroborate with non‐nucleophilic bases. This presents a new methodology for simultaneous functionalization of both cage carbon and boron vertices.
A Square‐Planar Tetracoordinate Oxygen‐Containing Ti4O17 Cluster Stabilized by Two 1,1′‐Ferrocenedicarboxylato Ligands
Authors: Liu Zhichang , Lei Juying , Frasconi Marco , Li Xiaohu , Cao Dennis , Zhu Zhixue , Schneebeli Severin T. , Schatz George C. , Stoddart J. Fraser 
Published: July 2014

AbstractBy introducing steric constraints into molecular compounds, it is possible to achieve atypical coordination geometries for the elements. Herein, we demonstrate that a titanium‐oxo cluster [{Ti4(μ4‐O)(μ2‐O)2}(OPri)6(fdc)2], which possesses a unique edge‐sharing Ti4O17 octahedron tetramer core, is stabilized by the constraints produced by two orthogonal 1,1′‐ferrocenedicarboxylato (fdc) ligands. As a result, a square‐planar tetracoordinate oxygen (ptO) can be generated. The bonding pattern of this unusual anti‐van’t Hoff/Le Bel oxygen, which has been probed by theoretical calculations, can be described by two horizontally σ‐bonded 2px and 2py orbitals along with one perpendicular nonbonded 2pz orbital. While the two ferrocene units are separated spatially by the ptO with an Fe⋅⋅⋅Fe separation of 10.4 Å, electronic communication between them still takes place as revealed by the cluster’s two distinct one‐electron electrochemical oxidation processes.
A Borinic Acid Polymer with Fluoride Ion‐ and Thermo‐responsive Properties that are Tunable over a Wide Temperature Range
Authors: Wan Wen‐Ming , Cheng Fei , Jäkle Frieder 
Published: July 2014

AbstractA new type of smart borinic acid polymer with luminescence and multiple stimuli‐responsive properties is reported. In DMSO with small amounts of water, the homopolymer PBA shows a tunable upper critical solution temperature (UCST). As the amount of water increases from 0 to 2.5 % (v/v), the UCST rises linearly from 20 °C to 100 °C (boiling point of water). Thus, the thermal responsive behavior can be tuned over a wide temperature range. Furthermore, polymer solutions in DMSO show a reversible response to fluoride ions, which can be correlated to the presence of the Lewis acidic borinic acid groups. Upon addition of fluoride, the polymer becomes soluble because the functional R2BOH groups are converted into ionic [R2BF2]− groups, but turns insoluble again upon addition of H2O, which reverses this process.
Observation of Paramagnetic Raman Optical Activity of Nitrogen Dioxide
Authors: Šebestík Jaroslav , Bouř Petr 
Published: July 2014

AbstractRaman optical activity (ROA) detects the intensity difference between right and left circularly polarized scattered light, and thus brings about enhanced information about the molecules under investigation. The difference is quite small and the technique is mostly constrained to the condensed phase. For NO2 in the presence of a static magnetic field, however, the ROA signal with high ROA/Raman intensity ratio was observed. The signal is so strong owing to molecular paramagnetism and a pre‐resonance signal enhancement. The spectral shape was explained on the basis of the Fermi golden rule and rotational wave functions expanded to a spherical top basis. The results indicate that the technique can be immediately used to obtain information about molecular properties, such as polarizability components. It also has a potential to detect other paramagnetic gases and discriminate among them.
A New Reactivity Mode for the Diazo Group: Diastereoselective 1,3‐Aminoalkylation Reaction of β‐Amino‐α‐Diazoesters To Give Triazolines
Authors: Kuznetsov Alexey , Gulevich Anton V. , Wink Donald J. , Gevorgyan Vladimir 
Published: July 2014

AbstractA novel mode of reactivity for the diazo group, the 1,3‐addition of a nucleophile and an electrophile to the diazo group, has been realized in the intramolecular aminoalkylation of β‐amino‐α‐diazoesters to form tetrasubstituted 1,2,3‐triazolines. The reaction exhibited a broad scope, good functional group tolerance, and excellent diastereoselectivity. In addition, a new Au‐catalyzed intramolecular transannulation reaction of the obtained propargyl triazolines to give pyrroles has been discovered.
Chain‐Terminating and Clickable NAD+ Analogues for Labeling the Target Proteins of ADP‐Ribosyltransferases
Authors: Wang Yan , Rösner Daniel , Grzywa Magdalena , Marx Andreas 
Published: July 2014

AbstractADP‐ribosyltransferases (ARTs) use NAD+ as a substrate and play important roles in numerous biological processes, such as the DNA damage response and cell cycle regulation, by transferring multiple ADP‐ribose units onto target proteins to form poly(ADP‐ribose) (PAR) chains of variable sizes. Efforts to identify direct targets of PARylation, as well as the specific ADP‐ribose acceptor sites, must all tackle the complexity of PAR. Herein, we report new NAD+ analogues that are efficiently processed by wild‐type ARTs and lead to chain termination owing to a lack of the required hydroxy group, thereby significantly reducing the complexity of the protein modification. Due to the presence of an alkyne group, these NAD+ analogues allow subsequent manipulations by click chemistry for labeling with dyes or affinity markers. This study provides insight into the substrate scope of ARTs and might pave the way for the further developments of chemical tools for investigating PAR metabolism.
BH, CH, and BC Bond Activation: The Role of Two Adjacent Agostic Interactions
Authors: Cassen Audrey , Gloaguen Yann , Vendier Laure , Duhayon Carine , Poblador‐Bahamonde Amalia , Raynaud Christophe , Clot Eric , Alcaraz Gilles , Sabo‐Etienne Sylviane 
Published: July 2014

AbstractTuning the nature of the linker in a L∼BHR phosphinoborane compound led to the isolation of a ruthenium complex stabilized by two adjacent, δ‐CH and ε‐Bsp2H, agostic interactions. Such a unique coordination mode stabilizes a 14‐electron “RuH2P2” fragment through connected σ‐bonds of different polarity, and affords selective BH, CH, and BC bond activation as illustrated by reactivity studies with H2 and boranes.
Comparative analysis of different properties of polyhydroxyalkanoates isolated from two different bacterial strains: Alkaliphilus oremlandii OhILAs and recombinant Escherichia coli XL1B
Authors: Pramanik Nilkamal , Mukherjee Khushi , Nandy Arpita , Mukherjee Shritama , Kundu Patit Paban 
Published: July 2014

ABSTRACTWe synthesized poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) [P(3‐HB‐co‐3‐HV)] copolymer having different contents of 3‐hydroxyvalerate (3‐HV) units (16.04, 16.3, 24.95, 25.62, and 16.52 mol % 3‐HV) with different yields of polyhydroxyalkanoates (PHAs) by feeding with different cooking oils and with Alkaliphilus oremlandii OhILAs strain. The PHA production efficiency of the Alkaiphilus strain was compared with that of the control strain, Bacillus cereus. The synthesis of each PHA biopolymer was performed with different toxic spent oils as the sole carbon source in an oil‐in‐water‐based microemulsion medium. We observed that the productivity of the poly(3‐hydroxybutyrate) [P(3‐HB)] copolymer from the Alkaliphilus strain was higher than those of the PHAs isolated from B. cereus and the Escherichia coli XL1B strain. The synthesized PHA copolymers were characterized by 1H‐NMR and Fourier transform infrared (FTIR) spectroscopy. In the 1H‐NMR spectra, a doublet resonance peak at 1.253 ppm of the/ methyl protons of the 3‐hydroxybutyrate (3‐HB) side group and one at 0.894 ppm due to the methyl protons of the 3‐HV side group indicated the presence of 3‐HB and 3‐HV units in the copolymer. The chemical shift values at 1.25 and 2.2 ppm, due to the resonance absorption peaks of the methyl protons and methylene protons, confirmed the synthesis of the P(3‐HB) homopolymer. From the FTIR spectra, a strong CO stretching frequency in the range of 1745–1727 cm−1, together with strong CO stretching bands near 1200 cm−1 and a strong band near 3400 cm−1, confirmed the synthesis of P(3‐HB‐co‐3‐HV) and P(3‐HB). Thus, waste cooking oil as a substrate provided an alternate route for the formation of P(3‐HB‐co‐3‐HV) and P(3‐HB) by Alkaliphilus and E. coli strains, respectively. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41080.
Physical aging of partially crosslinked RTM6 epoxy resin
Authors: Moosburger‐Will Judith , Greisel Michael , Horn Siegfried 
Published: July 2014

ABSTRACTThe aging behavior of partially and completely crosslinked RTM6 epoxy resin samples in the glassy state is investigated by thermophysical and mechanical analyses. Curing degree, glass transition temperature, density, and micromechanical modulus are investigated as function of aging period, initial curing degree or depth below the sample surface. A clear increase of density and modulus with aging period as well as an enhanced surface stiffness is detected for all curing degrees. Also, the aging period necessary to achieve the steady state modulus is independent from the curing degree. In contrast, the degree of physical aging induced modulus changes shows a significant dependence on the curing degree. A discontinuity is detected in the so‐called transition region, which is related to the transition from rubber to glassy state during crosslinking. This emphasizes the importance of curing history for physical aging processes and the high potential of partial curing for the development of new processing routes, in particular for production of samples with low sensitivity to physical aging. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41121.
Synthesis of a novel curing agent containing organophosphorus and its application in flame‐retarded epoxy resins
Authors: Xu Miaojun , Zhao Wei , Li Bin 
Published: July 2014

ABSTRACTA novel amine‐terminated and organophosphorus‐containing compound m‐aminophenylene phenyl phosphine oxide oligomer (APPPOO) was synthesized and used as curing and flame‐retarding agent for epoxy resins. Its chemical structure was characterized by Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (1H NMR), 13C nuclear magnetic resonance, and 31P nuclear magnetic resonance. The flame‐retardant properties, combusting performances, and thermal degradation behaviors of the cured epoxy resins were investigated by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter test, and thermogravimetric analysis. The EPO/APPPOO thermosets passed V‐1 rating with the thickness of 3.0 mm and the LOI value reached 34.8%. The thermosets could pass V‐2 rating when the thickness of the samples was 1.6 mm. The cone calorimeter test demonstrated that the parameters of EPO/APPPOO thermosets including heat release rate and total heat release significantly decreased compared with EPO/PDA thermosets. Scanning electron microscopy revealed that the incorporation of APPPOO into epoxy resins obviously accelerated the formation of the compact and stronger char layer to improve flame‐retardant properties of the cured epoxy resins during combustion. The mechanical properties and water resistance of the cured epoxy resins were also measured. After the water‐resistance test, EPO/APPPOO thermosets still remained excellent flame retardant and the water uptake was only 0.4%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41159.
The shark fishery in the United Arab Emirates: an interview based approach to assess the status of sharks
Authors: Jabado Rima W. , Al Ghais Saif M. , Hamza Waleed , Henderson Aaron C. 
Published: July 2014

Abstract

Anecdotal evidence suggests that sharks are being targeted in the United Arab Emirates artisanal fishery. However, little information is available on this fishery and baseline information is essential for understanding its impact on shark populations in the Arabian/Persian Gulf, and for managing sharks in this region.
The aim of this study was to investigate the artisanal shark fishery and gain an insight into the social, motivational and economic drivers behind it. Fishery characteristics were examined and the effect of fishing on local shark stocks assessed by interviewing Emirati fishermen across the country (n = 126).
Sharks were found to be increasingly targeted owing to their high value in the global fin trade industry. The majority of fishermen (80%) confirmed that changes in species composition, abundance and sizes of sharks have been continuing for more than two decades, mainly because of overfishing, raising concerns about the sustainability of this fishery.
Results suggest that sharks are likely to be overexploited and that management measures will need to take into account the precautionary principle. There is an urgent need to formulate long‐term and effective conservation and management plans to prevent further declines in a number of species.
Additional efforts should be directed to quantify the ecological implications of the observed changes and determine if these are aggravated by the life‐history traits of the fished species. Such implications should be considered when assessing the sustainability of local fisheries.
The data gathered can now serve as a reference to managers, fisheries scientists and other stakeholders to prioritize future research as well as lay foundations for the development and implementation of national management plans for the protection and conservation of sharks.
Copyright © 2014 John Wiley & Sons, Ltd.
1,4‐Dihydropyrrolo[3,2‐b]pyrrole and Its π‐Expanded Analogues
Authors: Janiga Anita , Gryko Daniel T. 
Published: July 2014

AbstractVarious approaches to the synthesis of 1,4‐dihydropyrrolo[3,2‐b]pyrroles are summarized. Many two‐ and three‐step reaction sequences have been developed, and have allowed access to a broad variety of structures, including not only the parent 1,4‐dihydropyrrolo[3,2‐b]pyrroles, but also their π‐expanded analogues. The newest approaches are critically compared with older strategies. The reactivity of these compounds is also reviewed, with special emphasis on electrophilic aromatic substitution. The synthesis of indolo[3,2‐b]indole derivatives has been the subject of intense investigation. Overall, a few interesting and ingenious approaches toward these ladder‐type heteroacenes have been proposed, reaching total yields in the region of 30 %. Finally, the optical, electrochemical, and other physicochemical properties are presented in the broader perspective of heteropentalenes. The parent 1,4‐dihydro‐pyrrolo[3,2‐b]pyrroles constitute the most electron‐rich, simple, aromatic heterocycles, and their simple derivatives and π‐expanded analogues possess strong violet, blue, or green fluorescence both in solution and in the solid state.
Regioselective C3 Alkenylation of 4 H‐pyrido[1,2‐a]pyrimidin‐4‐ones via Palladium‐Catalyzed CH Activation
Authors: Liu Wenjie , Wang Shaohua , Zhang Qi , Yu Jingwen , Li Jiahe , Xie Zhiwei , Cao Hua 
Published: July 2014

AbstractA general and efficient palladium‐catalyzed direct C3 alkenylation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones using AgOAc/O2 as the oxidant has been developed. A variety of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones were successfully coupled with acrylate esters, styrenes, methylvinylketone, and acrylamide in moderate to excellent yields. The reaction exhibited complete regio‐ and stereoselectivity. This transformation provides an attractive new approach to functionalize 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones.