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Engineered cytochrome c -catalyzed Lactone-carbene B-H Insertion

SYNLETT 2019年第4期30卷 378-382页

作者： chen, Kai Huang, Xiongyi Zhang, Shuo-Qing Zhou, Andrew Z. Kan, S. B. Jennifer Hong, Xin Arnold, Frances H. CALTECH Div Chem & Chem Engn 210 41 Pasadena CA 91125 USA Zhejiang Univ Dept Chem Hangzhou 31007 Zhejiang Peoples R China

Previous work has demonstrated that variants of a heme protein, Rhodothermus marinus cytochrome c ( Rma cyt c ), catalyze abiological carbene boron-hydrogen (B-H) bond insertion with high efficiency and selectivity. Here we investigated this carbon-boron bond-forming chemistry with cyclic, lactone-based carbenes. Using directed evolution, we obtained a Rma cyt c variant BOR (LAc) that shows high selectivity and efficiency for B-H insertion of 5- and 6-membered lactone carbenes (up to 24,500 total turnovers and 97.1:2.9 enantiomeric ratio). The enzyme shows low activity with a 7-membered lactone carbene. computational studies revealed a highly twisted geometry of the 7-membered lactone carbene intermediate relative to 5- and 6-membered ones. Directed evolution of cytochrome c together with computational characterization of key iron-carbene intermediates has allowed us to expand the scope of enzymatic carbene B-H insertion to produce new lactone-based organoborons.

关键词： cytochrome c carbene organoboron lactones biocatalyst directed evolution

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Rationally designed c/co9S8@SnS2nanocomposite as a highly efficient anode for lithium-ion batteries

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NANOTEcHNOLOGY 2020年第39期31卷 395401-395401页

作者： Zhang, Peng Liu, Yang Zhou, Min Xue, Yuxiong Zeng, Xianghua Qi, Junlei chen, Minghua Sun, Fenglian Yangzhou Univ Coll Elect Energy & Power Engn Yangzhou Jiangsu Peoples R China Harbin Univ Sci & Technol Sch Mat Sci & Engn Harbin Peoples R China Yangzhou Univ Coll Phys Sci & Technol Yangzhou Jiangsu Peoples R China Yangzhou Univ Inst Optoelect Technol Yangzhou Jiangsu Peoples R China Harbin Inst Technol State Key Lab Adv Welding & Joining Harbin Peoples R China Harbin Univ Sci & Technol Sch Appl Sci Harbin Peoples R China

Nanostructured transition metal sulfides are promising anode materials for lithium-ion batteries. Nevertheless, it is still a great challenge to prepare capacity-improved electrodes without reducing their rate capability and cycle stability. In this paper, we present a c/co9S8@SnS(2)composite material by loading SnS(2)nanocrystals onto MOF-derived c/co(9)S(8)nanostructures. The c/co9S8@SnS(2)composite has multiple active sites to store lithium ions. The specific capacity reaches 3.1 mAh cm(-2)when the current density is 0.224 mA cm(-2). The asynchronous electrochemical reaction between co(9)S(8)and SnS(2)offsets the volume expansion of the anode material. Meanwhile, the compact adhesion of carbon layers on the interfaces suppresses the destruction of the anode during the charging-discharging processes. consequently, the synthesized electrode presents favorable capacity with high current density or under long-term cycling conditions. The prepared battery has a reversible specific capacity of 0.452 mAh cm(-2)and a coulomb efficiency of 99.7% after 500 cycles with a high current density of 2.24 mA cm(-2). The research results obtained in this work provides a feasible strategy to improve the performance of electrodes systematically.

关键词： c co9S8@SnS2 lithium-ion batteries nanostructures MOFs transition metal sulfide

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Selective N-Monomethylation of Anilines with Methanol catalyzed by commercial Pd/c as an Efficient and Reusable catalyst

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ASIAN JOURNAL OF ORGANIc cHEMISTRY 2019年第11期8卷 2046-2049页

作者： Jiang, Lei Guo, Fang Wang, Yinran Jiang, Jialin Duan, Yangzhi Hou, Zhaomin Dalian Univ Technol Sch Chem Engn Dept Polymer Sci & Engn State Key Lab Fine Chem Dalian 116012 Peoples R China RIKEN Organometall Chem Lab 2-1 Hirosawa Wako Saitama 3510198 Japan RIKEN Ctr Sustainable Resource Sci 2-1 Hirosawa Wako Saitama 3510198 Japan

N-methylation of amines is one of the most important c-N bond-forming reactions and is widely utilized for the synthesis of numerous agrochemicals, drugs, natural products, and dyes. In this paper, the N-monomethylation of aniline derivatives using Pd/c catalyst and methanol as the methylation reagent was investigated. The N-monomethylation of various anilines was achieved with high activity and selectivity under relatively mild reaction conditions, and the yield of N-monomethyl anilines was over 90 %. Notably, the commercial, readily available, and inexpensive heterogeneous catalyst, Pd/c, could be easily recovered and reused more than five times with only a slight decrease in activity;gram-scale experiments were also successfully performed.

关键词： Pd c selective N-methylation methanol

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Design, Realization, and characterization of Advanced Adhesives for Joining Ultra-Stable c/c Based components

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MAcROMOLEcULAR MATERIALS AND ENGINEERING 2020年第9期305卷 2000229-2000229页

作者： casalegno, Valentina De la Pierre des Ambrois, Stefano corazzari, Ingrid Turci, Francesco Tatarko, Peter Damiano, Olivier cornillon, Laurence Terenzi, Andrea Natali, Maurizio Puglia, Deborah Torre, Luigi Ferraris, Monica Politecn Torino Dept Appl Sci & Technol DISAT Corso Duca Abruzzi I-2410129 Turin Italy Univ Torino Dept Chem I-710125 Turin Italy Univ Torino G Scansetti Interdept Ctr Study Asbestos & Other Via Pietro Giuria I-710125 Turin Italy Slovak Acad Sci Inst Inorgan Chem Dubravska Cesta 9 Bratislava 84536 Slovakia Thales Alenia Space 5 Allee GabiansBP99 F-06156 Cannes La Bocca France Univ Perugia Civil & Environm Engn Dept I-06123 Perugia Italy

The aim of this work is to develop high-performance adhesives to join carbon fiber reinforced composites (c/c) for use in aerospace applications;in order to guarantee sound mechanical strength, a low coefficient of thermal expansion, and ease of application on large components. Several different adhesive formulations, based on phenolic or cyanate-ester resins (charged with the maximum experimentally feasible amount of carbon-based fillers), are developed and tested. The measurements of the lap shear strength at room temperature of the c/c joined by means of one phenolic and one cyanate ester-based resin demonstrates that these formulations are the most suitable for the given application. A complete characterization, by means of viscosimetry, dilatometry, and thermal gravimetric analysis, coupled with gas analysis by means of mass spectroscopy, confirms that the phenolic-based formulation is the most promising joining material. A nano-indenter is used to obtain its Young modulus and hardness, both inside the joint and as a bulk cured adhesive.

关键词： c c composites joining ultra-stable adhesives

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core-Shell FeSe2/c Nanostructures Embedded in a carbon Framework as a Free Standing Anode for a Sodium Ion Battery

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SMALL 2020年第47期16卷 e2002200-e2002200页

作者： Yousaf, Muhammad Wang, Zhipeng Wang, Yunsong chen, Yijun Ali, Usman Maqbool, Muhammad Imran, Ali Mahmood, Nasir Gao, Peng Han, Ray P. S. Peking Univ Int Ctr Quantum Mat & Electron Microscopy Lab Sch Phys Beijing 100871 Peoples R China Peking Univ Dept Mat Sci & Engn Beijing 100871 Peoples R China Peking Univ Sch Phys Artificial Micro & Mesoscop Phys Beijing 100871 Peoples R China RMIT Univ Sch Engn 124 La Trobe St Melbourne Vic 3001 Australia Jiangxi Univ Tradit Chinese Med Canc Res Ctr Nanchang 330004 Jiangxi Peoples R China

Embedding the functional nanostructures into a lightweight nanocarbon framework is very promising for developing high performance advanced electrodes for rechargeable batteries. Here, to realize workable capacity, core-shell (FeSe2/c) nanostructures are embedded into carbon nanotube (cNT) framework via a facile wet-chemistry approach accompanied by thermally induced selenization. The cNT framework offers 3D continuous routes for electronic/ionic transfer, while macropores provide adequate space for high mass loading of FeSe2/c. However, the carbon shell not only creates a solid electronic link among cNTs and FeSe2 but also improves the diffusivity of sodium ions into FeSe2, as well as acts as a buffer cushion to accommodate the volume variations. These unique structural features of cNT/FeSe2/c make it an excellent host for sodium storage with a capacity retention of 546 mAh g(-1) even after 100 cycles at 100 mA g(-1). Moreover, areal and volumetric capacities of 5.06 mAh cm(-2) and 158 mAh cm(-3) are also achieved at high mass loading 16.9 mg cm(-2), respectively. The high performance of multi-benefited engineered structure makes it a potential candidate for secondary ion batteries, while its easy synthesis makes it extendable to further complex structures with other morphologies (such as nanorods, nanowires, etc.) to meet the high energy demands.

关键词： cNT FeSe2 c double cage protection system free standing electrode high areal capacity sodium ion battery

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Double Heterozygosity for Hb Durham-Nc (HBB: c.344T>c) [β114(G16)Leu→Pro] and the IVS-I-110 (HBB: c.93-21G>A) causing a Severe β-Thalassemia Phenotype

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HEMOGLOBIN 2019年第3期43卷 210-213页

作者： cannata, Monica cassara, Filippo Vinciguerra, Margherita Licari, Paola Passarello, cristina Leto, Filippo Lo Pinto, carmen Pitrolo, Lorella Ganci, Riccardo Maggio, Aurelio Giambona, Antonino Villa Sofia Cervello Hosp Lab Mol Diag Rare Dis Dept Hematol Rare Dis Blood & Blood Forming Organ Via Trabucco 180 I-90146 Palermo Italy Villa Sofia Cervello Hosp Dept Pediat Palermo Italy

The evaluation of a 10-month-old girl of Sicilian origin with a clinical phenotype of severe thalassemia led to the identification of two beta-globin gene defects, a beta-thalassemia (beta-thal), mutation at IVS-I-110 (HBB: c.93-21G>A) and a variant hemoglobin (Hb) mutation at codon 114 (HBB: c.344T>c) on the other allele, reported as Hb Durham-N.c. (also known as Hb Brescia) [beta 114(G16)Leu -> Pro] in the HbVar database. A very low Hb level (Hb 3.5 g/dL), microcytosis [mean corpuscular volume (McV) 63.2 fL] and hypocromia [mean corpuscular Hb (McH) 19.6 pg], increased red blood cell (RBc) distribution width (RDW) (36.0%), higher reticulocytes (6.2%), anisocytosis, poikilocytosis, hypocromia, basophilic stippling and inclusion body formation, were present in the affected subject. Analysis of other family components showed the presence of HBB: c.93-21G>A defect in the mother and in her brother, while Hb Durham-N.c. was absent in all other relatives, thus, this mutation has arisen as a de novo defect. This is the first case described as a severe thalassemic phenotype in a compound heterozygote carrier of this unstable Hb and a common beta-thalassemic allele. The important information gained from this case is that a rare dominant or recessive mutation may arise in every individual, even if this is a very rare event.

关键词： Autosomal dominant HBB mutation hemoglobin (Hb) Hb Durham-N c de novo HBB mutation unstable hemoglobin (Hb)

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Preparation and characterization of N-doped TiO2/c composite

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MATERIALS RESEARcH EXPRESS 2020年第6期7卷

作者： Leng, Senlin Ran, Yaozong Yang, Yingchang Tongren Univ Sch Mat & Chem Engn Res Ctr Mat & Chem Engn Tongren 554300 Peoples R China

In this work, the N-doped TiO2/c composite is successfully prepared using electrospinning technique. TEM, XPS and Raman techniques are used to characterize the morphologies and microstructure of the as-fabricated composite, confirming that the incorporation of N into TiO2/c can not only reduce the d-spacing of TiO2 nanocrystals, but also can transform it into another TiO2 crystal form. Furthermore, amorphous carbon in this composite can be transferred to graphite under the effect of TiO2 during calcination processes. The N-doped TiO2/c sample with variable pore sizes exhibit the largest specific surface area, and the crystal forms of TiO2 are close related to the value of specific surface area and the pore sizes.

关键词： TiO2 c N-doped TEM Raman

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Research on Material Removal Mechanism of c/Sic composites in Ultrasound Vibration-Assisted Grinding

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MATERIALS 2020年第8期13卷 1918页

作者： Wang, Dongpo Lu, Shouxiang Xu, Dong Zhang, Yuanlin Beihang Univ Sch Mech Engn & Automat Beijing 100191 Peoples R China Dalian Univ Technol Minist Educ Key Lab Precis & Nontradit Machining Technol Dalian 116024 Peoples R China Beihang Univ Sch Automat Sci & Elect Engn Beijing 100191 Peoples R China

c/Sic composites are the preferred materials for hot-end structures and other important components of aerospace vehicles. It is important to reveal the material removal mechanism of ultrasound vibration-assisted grinding for realizing low damage and high efficiency processing of c/Sic composites. In this paper, a single abrasive particle ultrasound vibration cutting test was carried out. The failure modes of Sic matrix and carbon fiber under ordinary cutting and ultrasound cutting conditions were observed and analyzed. With the help of ultrasonic energy, compared with ordinary cutting, under the conditions of ultrasonic vibration-assisted grinding, the grinding force is reduced to varying degrees, and the maximum reduction ratio reaches about 60%, which means that ultrasonic vibration is beneficial to reduce the grinding force. With the observation of cutting debris, it is found that the size of debris is not much affected by the cs>apcs> with ultrasound vibration. Thus, the ultrasound vibration-assisted grinding method is an effective method to achieve low damage and high efficiency processing of c/Sic composites.

关键词： c Sic composites ultrasound vibration material removal mechanism

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New Electrochemical Approach for the Synthesis of Pd-PdO/c Electrocatalyst and Application to Formic Acid Electrooxidation

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cHEMISTRYSELEcT 2019年第29期4卷 8390-8393页

作者： Kuriganova, Alexandra B. Faddeev, Nikita A. Leontyev, Igor N. Allix, Mathieu Rakhmatullin, Aydar Smirnova, Nina, V Platov South Russian State Polytech Univ NPI Prosvescheniya Str 132 Novocherkassk 346428 Russia Southern Fed Univ Zorge Str 5 Rostov Na Donu 344090 Russia Univ Orleans CEMHTI UPR3079 CNRS F-45071 Orleans France

Pd-PdO/c catalyst for formic acid electrooxidation has been synthesized via electrochemical dispersion of Pd foil electrodes under pulse alternating current conditions in Nacl aqueous electrolyte. About 35 wt% of the as-prepared Pd-PdO/c specimen is PdO as revealed by X-ray diffraction. The microstructural characteristics and catalytic activity of the synthesized Pd/c catalyst have been compared with those of a Pt/c catalyst prepared under the same conditions. Pd nanoparticles of Pd-PdO/c catalyst exhibit smaller average dimensions and narrower particle size distribution - 7.4 +/- 0.5 nm and 1.9 +/- 0.5 respectively for Pd and PdO particles. The process of ethanol electrooxidation on the catalyst was characterized by high overvoltage (up to 800 mV). The overvoltage of the formic acid electrochemical oxidation on Pd/c is 590 mV less than on Pt/c.

关键词： Pd c alternating current electrochemical dispersion formic acid fuel cell

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Russian doll architecture enables a high-rate and long-life Mnco2O4/c-lithium battery

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NANOTEcHNOLOGY 2020年第37期31卷 375404-375404页

作者： Hou, Li Deng, Shuolei Jiang, Yang cui, Ruiwen Zhou, Yanyan Guo, Yuanyuan Li, Jinghong Gao, Faming Yanshan Univ Key Lab Appl Chem Qinhuangdao 066004 Hebei Peoples R China

Realizing high capacity at high current densities is one of the challenges for battery electrode materials towards practical applications, especially for metal oxide electrode materials. Designing a specific structure that can alleviate volume expansion and accelerate the diffusion of the ions is an effective way to achieve this goal. Herein, a porous multilayer core-shell structured manganese cobalt oxide/carbon composite (Mnco2O4/c) was obtained by using a simple route that combines the hydrothermal method with calcination. The structure is similar to a Russian doll, which is nested with three to four layers of concentric porous shells. The porous multilayer core-shell structures can relieve volume expansion during discharge/charge and reduce the Li-ion diffusion path. Additionally, it can provide a richer activity site, thereby storing more lithium ions. When used as an anode material, the synthesized Mnco2O4/c showed a high specific capacity of 978 mAh g(-1)after 800 cycles at a current density of 1 A g(- 1). Even at a high current density of 10 A g(-1), the electrode could still deliver a specific capacity of 251 mAh g(-1), which makes it more suitable for powering large equipment such as electric vehicles.

关键词： transition metal oxide Mnco2O4 c hollow sphere lithium-ion battery

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