65 research outputs found

    1,3-Bis(2-cyano­benz­yl)imidazolium bromide

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    In the title salt, C19H15N4 +·Br−, the central imidazole ring makes dihedral angles of 83.1 (2) and 87.6 (2)° with the terminal benzene rings. The dihedral angle between the terminal benzene rings is 6.77 (19)°; the cyanide substituents have an anti orientation. In the crystal, the cations and anions are linked via C—H⋯N and C—H⋯Br hydrogen bonds, forming sheets lying parallel to the ac plane

    Metathesis of Fatty Acid Ester Derivatives in 1,1-Dialkyl and 1,2,3-Trialkyl Imidazolium Type Ionic Liquids

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    The self-metathesis of methyl oleate and methyl ricinoleate was carried out in the presence of ruthenium alkylidene catalysts 1–4 in [bmim] and [bdmim][X] type ionic liquids (RTILs) (X = PF6−, BF4− and NTf2−) using the gas chromatographic technique. Best catalytic performance was obtained in [bdmim][X] type ionic liquids when compared with [bmim][X] type ionic liquids. Catalyst recycling studies were also carried out in the room temperature ionic liquids (RTILs) with catalysts 1–4 in order to explore their possible industrial application

    R-Allyl Nickel(II) Complexes with Chelating N-Heterocyclic Carbenes: Synthesis, Structural Characterization, and Catalytic Activity

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    The N-heterocyclic carbene (NHC) nickel complexes [(L)Ni(NHC)][BArF4] (ArF = 3,5-bis(trifluoromethyl)- phenyl; L = allyl (1), methylallyl (2); NHC = 1-(2-picolyl)-3-methylimidazol-2-ylidene (a), 1-(2-picolyl)-3-isopropylimidazol-2-ylidene (b), 1-(2-picolyl)-3-n-butylimidazol-2-ylidene (c), 1-(2-picolyl)-3-phenylimidazol-2-ylidene (d), 1-(2-picolyl)-3- methylbenzoimidazol-2-ylidene (e), 1-(2-picolyl)-4,5-dichloro-3-methylimidazol-2-ylidene (f)) have been obtained in high yields and characterized by NMR spectroscopy. Furthermore, 1d was unambiguously characterized by single-crystal X-ray crystallography. Complexes 1a−f/2a−f have shown catalytic activity toward dimerization and hydrosilylation of styrenes. In particular, 1a proved to be the most efficient catalyst in the dimerization of styrene derivatives in the absence of cocatalyst. Also, complexes 1a,d showed high selectivity and moderate to good yields in hydrosilylation reactions

    Construction status and prospects of the Hyper-Kamiokande project

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    The Hyper-Kamiokande project is a 258-kton Water Cherenkov together with a 1.3-MW high-intensity neutrino beam from the Japan Proton Accelerator Research Complex (J-PARC). The inner detector with 186-kton fiducial volume is viewed by 20-inch photomultiplier tubes (PMTs) and multi-PMT modules, and thereby provides state-of-the-art of Cherenkov ring reconstruction with thresholds in the range of few MeVs. The project is expected to lead to precision neutrino oscillation studies, especially neutrino CP violation, nucleon decay searches, and low energy neutrino astronomy. In 2020, the project was officially approved and construction of the far detector was started at Kamioka. In 2021, the excavation of the access tunnel and initial mass production of the newly developed 20-inch PMTs was also started. In this paper, we present a basic overview of the project and the latest updates on the construction status of the project, which is expected to commence operation in 2027

    Prospects for neutrino astrophysics with Hyper-Kamiokande

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    Hyper-Kamiokande is a multi-purpose next generation neutrino experiment. The detector is a two-layered cylindrical shape ultra-pure water tank, with its height of 64 m and diameter of 71 m. The inner detector will be surrounded by tens of thousands of twenty-inch photosensors and multi-PMT modules to detect water Cherenkov radiation due to the charged particles and provide our fiducial volume of 188 kt. This detection technique is established by Kamiokande and Super-Kamiokande. As the successor of these experiments, Hyper-K will be located deep underground, 600 m below Mt. Tochibora at Kamioka in Japan to reduce cosmic-ray backgrounds. Besides our physics program with accelerator neutrino, atmospheric neutrino and proton decay, neutrino astrophysics is an important research topic for Hyper-K. With its fruitful physics research programs, Hyper-K will play a critical role in the next neutrino physics frontier. It will also provide important information via astrophysical neutrino measurements, i.e., solar neutrino, supernova burst neutrinos and supernova relic neutrino. Here, we will discuss the physics potential of Hyper-K neutrino astrophysics

    Video Streaming Framework

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    The framework for testing video streaming techniques is presented in this paper. Short review of error resilience and concealments tools available for the H.264/AVC standard is given. The video streaming protocols and the H.264 payload format are also described. The experimental results obtained with the framework are presented in this paper too

    Supplementary Material for: Progressive Central Artery Occlusion, Ophthalmic Artery Occlusion, and Hemispheric Intracranial Thrombosis after COVID-19 mRNA Vaccine Application- Case Report

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    Thromboembolic events as a result of COVID-19 mRNA vaccination are a rare, though life-threatening complication. In this case report, we describe a 40-year-old female patient who developed central retinal artery and ophthalmic artery occlusion progressing to intracranial thrombosis three weeks after vaccination with the Pfizer-BioNTech COVID-19 vaccine. Initially, she presented with progressive acute and painless unilateral vision loss in her left eye. Dilated fundoscopy of left eye showed macular whitening with sparing of the area of cilioretinal artery distribution. Labs revealed a normal erythrocyte sedimentation rate, C-reactive protein, and platelet count. Computerized tomogaphy angiography of the head and neck showed an occlusion of the entire left cervical internal carotid artery and occlusion of the origin of the left external carotid artery. Despite treatment with heparin, her vision declined to no light perception. Ten days later, the patient presented with right peripheral vision loss and was found to have a new left posterior cerebral artery/posterior inferior celebellar artery stroke. Seventeen days later, she presented to the hospital with nausea and vertigo and was found to have a subacute infarction in the left parietal lobe corresponding to left anterior communicating artery/middle celebral artery watershed territory. Hypercoagulable disorders, vasculitis, cardiac arrythmias, and intraventricular thrombi were excluded. Fundus fluorescein angiography confirmed central retinal artery occlusion and ophthalmic artery occlusion with impressive retina and choroid changes in fluorescein angiography patterns. This complication of mRNA COVID-19 vaccination has not been previously described in the literature and should be considered even weeks after initial presentation
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