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The electrocatalytic oxidation of organic molecules coupled with hydrogen evolution reaction can reduce overpotential and can be connected in series with nonelectrochemical processes to achieve the preparation of more high-value compounds. Herein, Cu- and Co-incorporated nickel hydroxide (CuCo-Ni(OH)2) was synthesized and applied to the anodic benzylamine oxidation reaction, which is 280 mV lower than the corresponding oxygen evolution reaction to reach the current density of 50 mA cm-2. When the electrocatalytic oxidation of benzylamine and hydrogen evolution reaction are coupled to form an electrolytic cell, the potential to reach 10 mA cm-2 is reduced by 197 mV compared to the overall water splitting. The benzylamine is converted to benzamide with 99.3% conversion and 90.2% faraday efficiency under 1.45 V constant voltage electrolysis, and the catalytic performance remains at a high level after 4 cycles. The characterization and density functional theory calculations show that Cu and Co share the transfer charge from Ni, making it easy for CuCo-Ni(OH)2 to deprotonate Ni-O* sites. The formed Ni-O* sites exhibit lower energy barriers in the proton transfer of benzylamine to benzonitrile and hydration intermediates, resulting in a better catalytic performance of CuCo-Ni(OH)2 than Ni(OH)2 in the electrocatalytic oxidation of benzylamine to benzamide.
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Despites Providencia heimbachae has been isolated from human, penguin, and bovine fetus, relatively little information is available regarding the pathogenicity and biologic characteristics of P. heimbachae. Here, we report that investigation of post-weaning diarrhea yielded bacterial isolates identified as P. heimbachae based on the biochemical tests and 16S ribosomal DNA sequence analysis. The two isolates were positive for utilization of Malonate, no gas production from glucose, and non-fermentation of D-mannitol, D-Galactose, and L-Rhamnose that were different from those of the type strain, and both of them have the ability of adhesion and invasion to IPEC-J2 cells, and were resistant to 21 out of the 41 antibiotics tested. In addition, the isolate 99101 was highly pathogenic to mice and piglets. Histopathology studies on nerve tissue of piglets that developed hindlimb paralysis showed microglia cell infiltration and neuron damage in the spinal cord. Notably, the strains could grow under low temperature (4 °C), which raise attention of a new risk factor for food safety. To the best of our knowledge, this is the first report of P. heimbachae strain caused post-weaning diarrhea in piglets in both natural and experimental conditions. These findings extended the knowledge of P. heimbachae as an important zoonotic agent, which should be given more attention during surveillance and diagnostics.
Asunto(s)
Providencia , Enfermedades de los Porcinos , Animales , Bovinos , Diarrea/veterinaria , Ratones , Fenotipo , Providencia/genética , Porcinos , DesteteRESUMEN
A copper-catalyzed asymmetric 1,3-dipolar cycloaddition of glycine iminoesters with alkyl substituted 3-methylene-2-oxindoles is described. By using de novo design of P-stereogenic phosphines as ligands, spiro[pyrrolidin-3,3'-oxindole]s are generated in good to excellent yields with high asymmetric induction. A further reduced catalyst loading of 0.1 mol% is sufficient to achieve a satisfactory enantioselectivity of 90% ee. The DFT calculations suggest the second Michael addition of the 1,3-dipole to be the rate- and enantio-determining step. A key feature of this 1,3-dipolar cycloaddition is the wide substrate applicability, even with alkyl aldehyde-derived azomethine ylide; thus it has streamlined a highly enantioselective access to a new class of antiproliferative agents, MDM2-p53.
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The aerobic oxidation of ethylbenzene is an effective way to produce acetophenone, in which solvent-free conditions and oxygen as the sole oxidant are the best choice. At present, the catalytic activity and selectivity are still at an unsatisfactory level, because efficient catalysts need to achieve both C-H bond activation and O2 activation. In this work, the 2-methylimidazole-induced hydrolysis strategy was used to prepare a new class of CoNi-layered double hydroxide (CoNi-LDH) materials with different metal ratios. High-Resolution Transmission Electron Microscopy (HRTEM) showed that CoNi-LDH had obvious weak crystallinity and a thin lamellar structure. X-ray Photoelectron Spectroscopy (XPS) reveals the consistency between the content of the M-O component in the host layer and the proportion of Co3+, among which CoNi-LDH with a feed ratio (Co : Ni) of 2 : 1 (Co2Ni-LDH) has the highest M-O content and Co3+ ratio. The formation of M-O is due to the H-vacancy generated by the breaking of the hydroxyl group, which can be used for the H abstraction of C-H bonds. The redox effect caused by M2+/M3+ facilitates the transfer of electrons, which promotes the activation of O2 to the superoxide radical anion (ËO2-). Thereby, Co2Ni-LDH shows the highest catalytic activity for the oxidation of ethylbenzene. Under solvent-free conditions and with oxygen as the sole oxidant, 97.8% conversion of ethylbenzene and 98.8% selectivity of acetophenone can be obtained. The excellent catalytic performance is related to the structure of CoNi-LDH, and is also the best when compared with the reported results. Various types of aromatic hydrocarbons containing benzyl C-H bonds can be effectively oxidized by CoNi-LDH to produce the corresponding ketone products.
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In the title compound, [Fe(C(5)H(5))(2)(C(13)H(11)N(2)O(2))], the dihedral angle between the benzene ring and the cyclo-penta-diene ring bonded to the carbonyl group is 26.1â (2)°. In the crystal, bifurcated O-Hâ¯(O,N) and N-Hâ¯O hydrogen bonds link the mol-ecules into a three-dimensional network.
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In the crystal structure of the title compound, C(9)H(9)N(3)O, adjacent mol-ecules are linked through N-Hâ¯N hydrogen bonds into a three-dimensional network.
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In the title complex, C(8)H(7)N(3)O, the C-O [1.369â (2) and 1.364â (3)â Å] and C=N [1.285â (3) and 1.289â (3)â Å] bond lengths in the oxadiazole ring are each almost identical within systematic errors, although different substituents are attached to the ring. The phenyl ring is inclined to the planar oxadiazole ring [r.m.s. deviation 0.002â Å] by 13.42â (18)°. In the crystal, molecules are linked via N-Hâ¯N hydrogen bonds, forming double-stranded chains propagating along [010].
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Non-invasive assessment of carotid artery plaque vulnerability is a key issue for cerebrovascular disease. This study investigates Von Mises strain imaging in patients by relating Von Mises strain to cerebral infarction presentation. Ultrasonography was performed in patients evaluated for carotid artery stenosis. Strains were estimated by a flow-driven diffusion method and least-squares regression applying Kalman filtering. Von Mises strains ÉVMsys and ÉVMdia were calculated by averaging four or five cardiac cycles in systole and diastole, respectively. Von Mises strain (peak, coefficient of variance, skewness and kurtosis) in patients with cerebral infarction was compared with that in the control group. Higher Von Mises peak strain localized to echolucent areas on B-mode imaging. Higher peak strain was found in patients with cerebral infarction compared with the control group (pâ¯=â¯0.02 for ÉVMdia and pâ¯=â¯0.001 for ÉVMsys). The area under the receiver operating characteristic curve for peak ÉVMsys was 0.761 (pâ¯=â¯0.001) with high sensitivity and specificity. Peak strain also correlated with homocysteine (râ¯=â¯0.345, pâ¯=â¯0.007, for ÉVMdia; râ¯=â¯0.287, pâ¯=â¯0.036, for ÉVMsys) and hypersensitive C-reactive protein (râ¯=â¯0.399, pâ¯=â¯0.043, for ÉVMdia; râ¯=â¯0.195, pâ¯=â¯0.034, for ÉVMsys) levels. The coefficient of variance, skewness and kurtosis of ÉVMdia or ÉVMsys were also associated with homocysteine levels. In conclusion, this study indicates that peak Von Mises strain is a potential clinical risk marker for carotid plaque vulnerability and cerebral infarction.
Asunto(s)
Arterias Carótidas/fisiopatología , Estenosis Carotídea/diagnóstico por imagen , Infarto Cerebral/diagnóstico , Infarto Cerebral/fisiopatología , Placa Aterosclerótica/diagnóstico por imagen , Ultrasonografía/métodos , Anciano , Arterias Carótidas/diagnóstico por imagen , Estenosis Carotídea/complicaciones , Infarto Cerebral/complicaciones , Femenino , Humanos , Masculino , Placa Aterosclerótica/complicaciones , Estudios Prospectivos , Factores de Riesgo , Sensibilidad y EspecificidadRESUMEN
The elasticity of the vessel wall is important for the clinical identification of rupture-risks. The Von Mises strain can be a potential index for the indication of carotid vessel pathologies. In this paper, a fast clinically applicable real-time algorithm from time-sequence of B-mode carotid images is developed. Due to the compression induced by the normal cardiac pulsation, tissue motion occurs radially and non-rigidly. To obtain an accurate motion field, we developed a variational functional integrating the optical flow equation and an anisotropic regularizer, and designed a diffusion tensor to encourage coherence diffusion. The motion field is smoothed along the desired motion flow orientation. A fast, additive operator splitting scheme, which is ten times faster than the conventional discrete method, is used for the numerical implementation. To demonstrate the efficiency of the proposed approach, finite element models are set up for normal and pathological carotid vessel walls. The results indicate that the proposed diffusion approach obtains an accurate smooth and continuous motion field and greatly improves the follow up strain estimation using a fast differential strain filter. Furthermore, our approach using the Von Mises strain imaging on clinical ultrasound images of the carotid artery is validated. Participants above 65-years in age suffering from different stages of atherosclerosis in their carotid artery are selected. The results are evaluated by an experienced physician. The evaluation results demonstrate that the Von Mises strain has a good correspondence to the presence of certain suspicious areas in the B-mode images. The proposed method is therefore clinically applicable for the real-time Von Mises strain imaging of carotid vessel walls, and can be of great value as a complementary method to B-mode image for the clinical identification of the risk of plaque vulnerability.