bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ischemic core thresholds change with time to reperfusion: A case control study
Authors: Bivard Andrew , Kleinig Tim , Miteff Ferdinand , Butcher Kenneth , Lin Longting , Levi Christopher , Parsons Mark 
Published: December 2017

IntroductionWe aimed to identify whether acute ischemic stroke patients with known complete reperfusion after thrombectomy had the same baseline computed tomography perfusion (CTP) ischemic core threshold to predict infarction as thrombolysis patients with complete reperfusion.MethodsPatients who underwent thrombectomy were matched by age, clinical severity, occlusion location, and baseline perfusion lesion volume to patients who were treated with intravenous alteplase alone from the International Stroke Perfusion Imaging Registry. A pixel‐based analysis of coregistered pretreatment CTP and 24‐hour diffusion‐weighted imaging (DWI) was then undertaken to define the optimum CTP thresholds for the ischemic core.ResultsThere were 132 eligible thrombectomy patients and 132 matched controls treated with alteplase alone. Baseline National Institutes of Health Stroke Scale (median, 15; interquartile range [IQR], 11–19), age (median, 65; IQR, 59–80), and time to intravenous treatment (median, 153 minutes; IQR, 82–315) were well matched (all p > 0.05). Despite similar baseline CTP ischemic core volumes using the previously validated measure (relative cerebral blood flow [rCBF], <30%), thrombectomy patients had a smaller median 24‐hour infarct core of 17.3ml (IQR, 11.3–32.8) versus 24.3ml (IQR, 16.7–42.2; p = 0.011) in alteplase‐treated controls. As a result, the optimal threshold to define the ischemic core in thrombectomy patients was rCBF <20% (area under the curve [AUC], 0.89; 95% CI, 0.84, 0.94), whereas in alteplase controls the optimal ischemic core threshold remained rCBF <30% (AUC, 0.83; 95% CI, 0.77, 0.85).InterpretationThrombectomy salvaged tissue with lower CBF, likely attributed to earlier reperfusion. For patients who achieve rapid reperfusion, a stricter rCBF threshold to estimate the ischemic core should be considered. Ann Neurol 2017;82:995–1003
High‐Flux Zeolitic Imidazolate Framework Membranes for Propylene/Propane Separation by Postsynthetic Linker Exchange
Authors: Lee Moon Joo , Kwon Hyuk Taek , Jeong Hae‐Kwon 
Published: December 2017

AbstractWhile zeolitic imidazolate framework, ZIF‐8, membranes show impressive propylene/propane separation, their throughput needs to be greatly improved for practical applications. A method is described that drastically reduces the effective thickness of ZIF‐8 membranes, thereby substantially improving their propylene permeance (that is, flux). The new strategy is based on a controlled single‐crystal to single‐crystal linker exchange of 2‐methylimidazole in ZIF‐8 membrane grains with 2‐imidazolecarboxaldehyde (ZIF‐90 linker), thereby enlarging the effective aperture size of ZIF‐8. The linker‐exchanged ZIF‐8 membranes showed a drastic increase in propylene permeance by about four times, with a negligible loss in propylene/propane separation factor when compared to as‐prepared membranes. The linker‐exchange effect depends on the membrane synthesis method.
Ultralong Phosphorescence from Organic Ionic Crystals under Ambient Conditions
Authors: Cheng Zhichao , Shi Huifang , Ma Huili , Bian Lifang , Wu Qi , Gu Long , Cai Suzhi , Wang Xuan , Xiong Wei‐wei , An Zhongfu , Huang Wei 
Published: December 2017

AbstractA new type of materials, organic salts in the crystal state, have ultralong organic phosphorescence (UOP) under ambient conditions. The change of cations (NH4+, Na+, or K+) in these phosphors gives access to tunable UOP colors ranging from sky blue to yellow green, along with ultralong emission lifetimes of over 504 ms. Single‐crystal analysis reveals that unique ionic bonding can promote an ordered arrangement of organic salts in crystal state, which then can facilitate molecular aggregation for UOP generation. Additionally, reversible ultralong phosphorescence can be realized through the alternative employment of fuming gases (ammonia and hydrogen chloride), demonstrating its potential as a candidate for visual ammonic or hydrogen chloride gas sensing. The results provide an environmental responsible and practicable synthetic approach to expanding the scope of ultralong organic phosphorescent materials as well as their applications.
Kovalente organische Netzwerke und Käfigverbindungen: Design und Anwendungen von polymeren und diskreten organischen Gerüsten
Authors: Beuerle Florian , Gole Bappaditya 
Published: December 2017

AbstractPoröse organische Materialien sind eine aufstrebende Klasse funktionaler Nanostrukturen mit beispiellosen Eigenschaften. Die dynamisch‐kovalente Organisation kleiner organischer Bausteine unter thermodynamischer Kontrolle wird dabei für die verblüffend einfache Bildung komplexer Architekturen in Eintopfreaktionen genutzt. In diesem Aufsatz werden die grundlegenden Designprinzipien analysiert, die zur Bildung von entweder kovalenten organischen Netzwerken als kristalline poröse Polymere oder kovalenten organischen Käfigverbindungen als formgetreue molekulare Objekte führen. Konventionelle Synthesevorschriften und Analysemethoden werden neben ausgefeilteren Strategien, wie postsynthetische Modifizierungen oder Selbstsortierung, diskutiert. Gegebenenfalls werden die entsprechenden Eigenschaften und Besonderheiten von polymeren Netzwerken und diskreten organischen Käfigen verglichen. Darüber hinaus wird das Potenzial dieser Materialien für Anwendungen, von der Gasspeicherung über die Katalyse bis hin zur organischen Elektronik, erörtert.
Formation and Isolation of a Four‐Electron‐Reduced Porphyrin Derivative by Reduction of a Stable 20π Isophlorin
Authors: Suzuki Wataru , Kotani Hiroaki , Ishizuka Tomoya , Shiota Yoshihito , Yoshizawa Kazunari , Kojima Takahiko 
Published: December 2017

AbstractThe two‐electron reduction of a diprotonated dodecaphenylporphyrin derivative by Na2S2O4 gave a corresponding isophlorin (Iph) selectively. Formation of Iph was confirmed by spectroscopic measurements and the isolation of tetramethylated Iph. Further reduction of Iph proceeded to form an unprecedented four‐electron‐reduced porphyrin (IphH2), which was fully characterized by spectroscopic and X‐ray crystallographic analysis. IphH2, with a unique conformation, could be oxidized to reproduce the starting porphyrin, resulting in a proton‐coupled four‐electron reversible redox system.
Triangles and Squares for a Unique Molecular Crystal Structure: Unsupported Two‐Coordinate Lithium Cations and CC Agostic Interactions in Cyclopropyllithium Derivatives
Authors: Dufrois Quentin , Daran Jean‐Claude , Vendier Laure , Dinoi Chiara , Etienne Michel 
Published: December 2017

AbstractUnderstanding and controlling the aggregation state is germane to alkyllithium chemistry. Lewis base‐free alkyllithium compounds normally form tetrahedral tetramers or octahedral hexamers in the solid state with the lithium cations being three‐coordinate. We report that the unsupported cyclopropyl derivative 1‐(trimethylsilyl)cyclopropyllithium [{μ‐c‐C(SiMe3)C2H4}Li]4 (1), synthesized by the reduction of 1‐(phenylthio)‐1‐(trimethylsilyl)cyclopropane, crystallizes as a tetramer in the space group I‐4 with the two‐coordinate lithium atoms forming a square. CC agostic interactions complete the coordination sphere around each lithium. The aggregate is preserved in hydrocarbon solution. Furthermore, CC agostic interactions compete intra‐ and intermolecularly with Lewis base donation as in the unsaturated dimer of 1‐(phenylthio)cyclopropyllithium [Li(thf)2{μ‐c‐C(SPh)C2H4}2Li (thf)] (3) which is also fully characterized.
Diversity‐Oriented Synthesis of Furo[3,2‐c]coumarins and Benzofuranyl Chromenones through Chemoselective Acylation/Wittig Reaction
Authors: Yang Shu‐Mei , Wang Chein‐Yi , Lin Chun‐Kai , Karanam Praneeth , Reddy Ganapuram Madhusudhan , Tsai Yi‐Ling , Lin Wenwei 
Published: December 2017

AbstractA highly efficient and chemoselective one‐pot protocol for the diversity‐oriented synthesis of two types of coumarin‐based formal cross‐coupling adducts, furo[3,2‐c]coumarins and 3‐benzofuranyl chromenones, is described. Key attributes of the methodology are an initial chemoselective acylation of functionalized phosphorus zwitterions and a subsequent chemoselective intramolecular Wittig reaction that preferentially resulted in one of the two coumarin derivatives in high yield, depending on relative reactivities and the addition sequence of the acylating agents.
Sinter‐Resistant Platinum Catalyst Supported by Metal–Organic Framework
Authors: Kim In Soo , Li Zhanyong , Zheng Jian , Platero‐Prats Ana E. , Mavrandonakis Andreas , Pellizzeri Steven , Ferrandon Magali , Vjunov Aleksei , Gallington Leighanne C. , Webber Thomas E. , Vermeulen Nicolaas A. , Penn R. Lee , Getman Rachel B. , Cramer Christopher J. , Chapman Karena W. , Camaioni Donald M. , Fulton John L. , Lercher Johannes A. , Farha Omar K. , Hupp Joseph T. , Martinson Alex B. F. 
Published: December 2017

AbstractSingle atoms and few‐atom clusters of platinum are uniformly installed on the zirconia nodes of a metal‐organic framework (MOF) NU‐1000 via targeted vapor‐phase synthesis. The catalytic Pt clusters, site‐isolated by organic linkers, are shown to exhibit high catalytic activity for ethylene hydrogenation while exhibiting resistance to sintering up to 200 °C. In situ IR spectroscopy reveals the presence of both single atoms and few‐atom clusters that depend upon synthesis conditions. Operando X‐ray absorption spectroscopy and X‐ray pair distribution analyses reveal unique changes in chemical bonding environment and cluster size stability while on stream. Density functional theory calculations elucidate a favorable reaction pathway for ethylene hydrogenation with the novel catalyst. These results provide evidence that atomic layer deposition (ALD) in MOFs is a versatile approach to the rational synthesis of size‐selected clusters, including noble metals, on a high surface area support.
Increasing Catalyst Efficiency in C−H Activation Catalysis
Authors: Gensch Tobias , James Michael J. , Dalton Toryn , Glorius Frank 
Published: December 2017

AbstractC−H activation reactions with high catalyst turnover numbers are still very rare in the literature and 10 mol % is a common catalyst loading in this field. We offer a representative overview of efficient C−H activation catalysis to highlight this neglected aspect of catalysis development and inspire future effort towards more efficient C−H activation. Examples ranging from palladium catalysis, Cp*RhIII‐ and Cp*CoIII‐catalysis, the C−H borylation and silylation to methane C−H activation are presented. In these reactions, up to tens of thousands of catalyst turnovers have been observed.
Kinetics of solid acids catalysed nitration of toluene: Change in selectivity by triphase (liquid–liquid–solid) catalysis
Authors: Jeeru Lakshmana Rao , R. V. Saikumar Reddy , Pradhan Sayantan , Kundu Gautam , Pradhan Narayan C. 
Published: December 2017

AbstractNitrotoluenes are precursors to a variety of commercially important products such as dyes, pharmaceuticals, and plastics. The protonated form of Y, ZSM‐5, and mordenite zeolites as well as strongly acidic cation exchange resin (Amberlite IR‐120) were examined as triphase catalyst (liquid–liquid–solid) for the nitration of toluene to produce mainly mononitrotoluenes. Among the solid acid catalysts tested, zeolites were found to be more active than cation exchange resin with highest activity for H‐mordenite followed by HZSM‐5 and HY zeolites. The reaction was found to be free from external diffusional resistance. The effects of other parameters (temperature, catalyst loading, and nitric acid concentration) on the rate of toluene nitration over H‐mordenite catalyst were also investigated. The selectivity for p‐nitrotoluene increases with temperature but decreases with increase in nitric acid concentration. The acidity level of the catalyst determines the product distribution; the stronger the acidity, the lower the ortho/para ratio is in the product mixture. The triphasic nitration reaction is kinetically controlled with an activation energy of 24.24 kJ/mol. The catalyst could be reused for several cycles with negligible loss in activity.
A versatile radiochromic dosimeter for low‐medium gamma radiation and its application to food irradiation
Authors: Lopes Franceline Aparecida , Ferreira Giovana Ribeiro , Franco Marcella Rocha , Schimitberger Thiago , de Faria Luiz Oliveira , Bianchi Rodrigo Fernando 
Published: December 2017

ABSTRACTThis article presents a novel radiochromic film for selective detection of low‐medium (0–10 kGy) gamma radiation (60Co) doses. This dosimeter is based on a printed fluorescent multilayer structure comprising a paper substrate having layers of copper phthalocyanine (DY220) (a green emitter material) on the bottom, and layers of poly[2‐methoxy‐5(2′‐ethylhexyloxy)‐p‐phenylenevinylene] (MEH‐PPV) (a green‐light absorber, red emitter, and radiation sensitive polymer) on the top. The effect of gamma radiation on the optical properties of DY220/MEH‐PPV was described: it was observed as a strong correlation between radiation dose and fluorescent, color coordinates for CIE (1931) chromatic diagram, and Pantone color reference of the dosimeter. The rate of these changes can be altered by manipulation of top–bottom layers to represent easily the radiation dose to be determined in a wide range. This versatile dosimeter has many uses in the field of food radiation for monitoring, quality assurance, and control of the gamma radiation process. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45729.
Low‐viscosity and soluble phthalonitrile resin with improved thermostability for organic wave‐transparent composites
Authors: Wu Zuoqiang , Li Nan , Han Jianhua , Wang Chenghao , Yuan Kuanyu , Zeng Qiang , Wang Jinyan , Jian Xigao 
Published: December 2017

ABSTRACTHigh processing viscosity and poor solubility limit the application of heterocyclic polymers for fabricating organic wave‐transparent composites for aerospace applications. In this paper, a novel resin, poly(phthalazinone ether bisphenol fluorene) encapped with phthalonitrile (PPEBF‐Ph), was synthesized and used as the matrix. Biphenol‐based phthalonitrile monomer BP‐Ph was also synthesized and blended with PPEBF‐Ph to further lower the processing viscosity. Solubility tests showed that the resin was soluble in dimethylformamide, N,N‐dimethyl acetamide, N‐methylpyrrolidone, dimethyl sulfoxide, chloroform, and other solvents. Differential scanning calorimetry and rheological studies revealed that the mixed resins exhibited low processing viscosity and a wide processing window below the gel temperature. Thermogravimetric analysis indicated that the cured resins were stable below 510–530 °C under nitrogen atmosphere after 6 h of curing (decreased by 40–60% compared with previous reports on phthalonitrile resin). In air, the char yields of the resins reached 20–30% when heated at 800 °C. The composites were reinforced by a quartz fiber cloth and exhibited a dielectric constant of 2.94–3.27 in an electromagnetic field with frequency ranging from 8 to 18 GHz. Retention of the bending modulus exceeded 70% at 400 °C according to dynamic mechanical analysis, indicating excellent mechanical stability was obtained. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45976.
Sustainable bionanocomposite from d,l‐lactide/δ‐valerolactone triblock and bionanowhiskers: Preparation, characterization, and properties
Authors: Kasyapi Nibedita , Dinesh Kumar K. , Bhowmick Anil K. 
Published: December 2017

ABSTRACTBionanocomposites were prepared using d,l‐lactide–δ‐valerolactone–d,l‐lactide triblock and unmodified and modified cellulose nanowhiskers (CNs) at different loadings (0, 2, 4, 8 wt %). Poly(δ‐valerolactone) chains were grafted on CNs for modification. These were characterized by various techniques. The broadening of OH (hydroxyl) stretching region and the presence of low‐intensity peaks at 1064 cm−1 for CO/CC stretching vibration and 1426 cm−1 for bending vibration of CH2 group, were evident in Fourier transform infrared spectra of the nanocomposites. The increase in crystallinity was noticed as the amount of nanowhiskers was increased. The nanowhiskers having the width in the range of 80–300 nm were uniformly dispersed in the triblock matrix. The tensile strength and modulus increased by 130% and 50% respectively at 8 wt % of filler loading. The storage modulus, loss modulus, complex viscosity, and tan δ values increased with increased filler loading. Further improvement in mechanical properties was observed with the modified CNs. The modulus mapping from atomic force microscopy confirmed the effective reinforcement behavior of the nanowhiskers. Scaffold fabrication using the bionanocomposite exhibited porous nature, having a homogeneous dispersion of CNs on the surface of the scaffold. The 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay confirmed the suitability of the composite material for scaffold application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 46035.
Recyclable, shape‐memory, and self‐healing soy oil‐based polyurethane crosslinked by a thermoreversible Diels–Alder reaction
Authors: Zheng Kaiwen , Tian Yazhou , Fan Mengjin , Zhang Junying , Cheng Jue 
Published: December 2017

ABSTRACTThe recyclable, shape‐memory, and self‐healing soy oil‐based polyurethane (S‐PU) networks were constructed by the thermoreversible Diels–Alder (DA) reaction between S‐PU (sealed with furfuryl alcohol) and 1,5‐bis(maleimido)‐2‐methylpentane. The DA and retro‐DA reactions between furan and maleimide were investigated by Fourier transform infrared spectroscopy, differential scanning calorimetry, solubility, and recycle testing. Moreover, the shape‐memory properties of the S‐PU networks were studied by qualitative recovery testing and quantitative cyclic tensile testing. Furthermore, the self‐healing properties of S‐PU networks were confirmed by cut, scratch, and tensile testing. The results showed that, compared to the traditional S‐PU, the novel S‐PU prepared in this work was recyclable and self‐healing. And although both of them have shape‐memory effect, the novel S‐PU has a higher shape fixed rate and shape recovered rate than the traditional S‐PU. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46049.
Biodegradation of pyridine‐based polyether polyurethanes by the Alternaria tenuissima fungus
Authors: Oprea Stefan , Potolinca Violeta Otilia , Gradinariu Petronela , Oprea Veronica 
Published: December 2017

ABSTRACTThe scope of the present work is to study the biodegradability behavior of several novel heterocyclic poly(ether urethanes) when their hard segments are subjected to exposure to the Alternaria tenuissima fungus. The heterocyclic poly(ether urethanes) were chain‐extended with various pyridine derivatives that had different functional groups placed in different positions on the pyridine rings. Different ratios of the reactive components were also used. The measurements obtained by the use of the attenuated total reflectance–Fourier transform infrared spectroscopy revealed the different structural changes that occurred after exposure to fungi. The degradation process was analyzed through measurement of the mechanical properties and surface morphology evolution by scanning electron microscopy. The obtained results show that the nature and design of the functional groups on the pyridine ring determine the strength of the cohesion linkages that in turn influence different degradation behaviors under exposure to fungi. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46096.
Potential Adult Neurogenesis in the Telencephalon and Cerebellar Cortex of the Nile Crocodile Revealed with Doublecortin Immunohistochemistry
Authors: Ngwenya Ayanda , Patzke Nina , Herculano‐Houzel Suzana , Manger Paul R. 
Published: December 2017

ABSTRACTThe brain of the crocodile is known to gain in mass allometrically throughout life, and the addition of neurons (as well as non‐neurons) appears to play a significant role in this increasing brain mass. We used immunohistochemistry in the brains of 12 Nile crocodiles ranging between 350 g and 86 kg in body mass and 1.99 g to 7.9 g in brain mass to identify the regions of the brain in which neurons immunopositive for doublecortin (DCX), a marker for potential adult neurogenesis, are found. Similar to other reptiles, potential newly born neurons, those immunopositive for DCX, were found throughout the telencephalon, the main and accessory olfactory bulbs and the olfactory tract, and in the cerebellar cortex; however, no DCX immunopositive neurons were observed in the diencephalon or brainstem. An apparent moderate decrease in the density of DCX labeled neurons in the olfactory bulbs and tract as well as the cerebellar cortex was observed with increasing brain mass, but the observed qualitative density of labeled neurons within the telencephalon was maintained irrespective of brain mass. Three potential neurogenic zones, within the sulci of the lateral ventricle, were identified, and these are similar to those seen in other reptiles. This study indicates that at least part of the gain in brain mass with age in the Nile crocodile may be accounted for by the potential addition and integration of new neurons into the existing circuitry, especially so for the olfactory system, telencephalon and cerebellar cortex. Anat Rec, 301:659–672, 2018. © 2017 Wiley Periodicals, Inc.
Unique performance of spaceborne SAR remote sensing in cultural heritage applications: Overviews and perspectives
Authors: Chen Fulong , You Jiangbin , Tang Panpan , Zhou Wei , Masini Nicola , Lasaponara Rosa 
Published: December 2017

AbstractTo be an innovative remote sensing technology, spaceborne synthetic aperture radar (SAR) is increasingly recognized as an irreplaceable tool in cultural heritage applications, such as archaeological prospection for the discovery of new sites and monument monitoring and management, taking advantage of observation capabilities independent of sun illumination and weather conditions. In this paper, we firstly give a synoptic overview for the state‐of‐art of spaceborne SAR technology in cultural heritage applications. Then, the unique performance of SAR compared with optical approaches, including subsurface imaging and interferometry, is objectively exploited and assessed using simulations and case studies. Simulations indicated that long wavelength SAR is promising in the detection of relics with an extended geometric dimension, particularly when the performance of tomographic SAR (TomoSAR) in subsurface imaging is optimized. However, case studies proved that interferometic SAR (InSAR) is useful for landscape archaeology by producing digital elevation models as well as for risk monitoring and preventive diagnosis of cultural properties using motion indicators. This study showed the potentialities of spaceborne SAR applications in cultural heritage, with particular reference to TomoSAR and differential TomoSAR (D‐TomoSAR).
Fractional Order Synchronous Reluctance Motor: Analysis, Chaos Control and FPGA Implementation
Authors: Rajagopal Karthikeyan , Nazarimehr Fahime , Karthikeyan Anitha , Srinivasan Ashokkumar , Jafari Sajad 
Published: December 2017

AbstractThis paper deals with the dynamical analysis and chaos control in a fractional order synchronous reluctance motor (FOSyncRM). Equilibrium points, characteristic equations and Eigen values of both commensurate and incommensurate FOSyncRM are presented. finite‐time Lyapunov exponents of the FOSyncRM system for fixed and varied parameters are investigated along with the bifurcation plots. Fractional order bifurcation plots are derived to show that the system shows more complex chaotic oscillations in fractional order. Chaos control in the FOSyncRM system is achieved using adaptive sliding mode controllers and the entire control algorithm is implemented in FPGA.