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排序方式: 共有1146条查询结果,搜索用时 10 毫秒
891.
Masanori Yamamoto Qi Zhao Shunsuke Goto Yu Gu Takaaki Toriyama Tomokazu Yamamoto Hirotomo Nishihara Alex Aziz Rachel Crespo-Otero Devis Di Tommaso Masazumi Tamura Keiichi Tomishige Takashi Kyotani Kaoru Yamazaki 《Chemical science》2022,13(11):3140
γ-Al2O3 nanoparticles promote pyrolytic carbon deposition of CH4 at temperatures higher than 800 °C to give single-walled nanoporous graphene (NPG) materials without the need for transition metals as reaction centers. To accelerate the development of efficient reactions for NPG synthesis, we have investigated early-stage CH4 activation for NPG formation on γ-Al2O3 nanoparticles via reaction kinetics and surface analysis. The formation of NPG was promoted at oxygen vacancies on (100) surfaces of γ-Al2O3 nanoparticles following surface activation by CH4. The kinetic analysis was well corroborated by a computational study using density functional theory. Surface defects generated as a result of surface activation by CH4 make it kinetically feasible to obtain single-layered NPG, demonstrating the importance of precise control of oxygen vacancies for carbon growth.Oxygen vacancies on the (100) surface of γ-Al2O3 nanoparticles catalyse CH4-CVD for single-layered nanoporous graphenes with no transition metal reaction centre. The rate-limiting step is the proton transfer (PT) in the activation of CH4 on them. 相似文献
892.
Tyler C. Beck Kendra Springs Jordan E. Morningstar Catherine Mills Andrew Stoddard Lilong Guo Kelsey Moore Cortney Gensemer Rachel Biggs Taylor Petrucci Jennie Kwon Kristina Stayer Natalie Koren Jaclyn Dunne Diana Fulmer Ayesha Vohra Le Mai Sarah Dooley Julianna Weninger Yuri Peterson Patrick Woster Thomas A. Dix Russell A. Norris 《Molecules (Basel, Switzerland)》2022,27(12)
Cancer is the second most common cause of death in the United States, accounting for 602,350 deaths in 2020. Cancer-related death rates have declined by 27% over the past two decades, partially due to the identification of novel anti-cancer drugs. Despite improvements in cancer treatment, newly approved oncology drugs are associated with increased toxicity risk. These toxicities may be mitigated by pharmacokinetic optimization and reductions in off-target interactions. As such, there is a need for early-stage implementation of pharmacokinetic (PK) prediction tools. Several PK prediction platforms exist, including pkCSM, SuperCypsPred, Pred-hERG, Similarity Ensemble Approach (SEA), and SwissADME. These tools can be used in screening hits, allowing for the selection of compounds were reduced toxicity and/or risk of attrition. In this short commentary, we used PK prediction tools in the optimization of mitogen activated extracellular signal-related kinase kinase 1 (MEK1) inhibitors. In doing so, we identified MEK1 inhibitors with retained activity and optimized predictive PK properties, devoid of hERG inhibition. These data support the use of publicly available PK prediction platforms in early-stage drug discovery to design safer drugs. 相似文献
893.
We consider the symmetry of discrete and continuous crystal structures which are compatible with a given choice of dislocation
density tensor. By introducing the notion of a ‘defective point group’ (determined by the dislocation density tensor), we
generalize the notion of Ericksen–Pitteri neighborhoods to this context. 相似文献
894.
895.
Numerical solution of the Helmholtz equation is a challenging computational task, particularly when the wave number is large. For two-dimensional problems, direct methods provide satisfactory solutions, but large three-dimensional problems become unmanageable. 相似文献
896.
Ben Dexter Annika Smith Rachel King Nathan J. Downs Catherine Jane Nikles Alfio V. Parisi Yik-Hong Ho Simone Lee Harrison 《Photochemistry and photobiology》2023,99(5):1352-1356
Skin cancer, the most prevalent cancer in Caucasians residing at low latitudes, can primarily be prevented by avoiding overexposure to sunlight. Serial cross-sectional observations were conducted at an outdoor motorsport event held in Townsville, Queensland each July (Southern winter) to determine whether sun-protection habits changed over time. Most (71.1%) of the 1337 attendees observed (97.6% lightly pigmented skin, 64.0% male) wore a hat (any style shading the face), while few (18.5%) wore three-quarter or full-length sleeves. While hat-wearing rates (any style) were similar in 2009 (326, 72.6%) and 2013 (625, 70.4%), the use of sun-protective styles (wide-brimmed/bucket/legionnaires) decreased from 29.2% to 18.6% over the same period, primarily because the use of sun-protective hats halved (from 28.7% to 14.0%) among females, while decreasing from 29.4% to 21.1% in males. Although relatively few individuals wore sun-protective (three-quarter-length or full-length) sleeves regardless of year (OR = 0.117, P < 0.0001), encouragingly, the use of sun-protective sleeves more than doubled between 2009 (10.5%) and 2013 (22.5%). Interestingly females, albeit the minority, at this sporting event were less likely to wear a hat (OR = 0.473, P < 0.0001) than males. These findings highlight the need for continued momentum toward skin cancer primary prevention through sun protection with a dedicated focus on outdoor sporting settings. 相似文献
897.
Yu Zhou Dr. Evan N. Mirts Sangdo Yook Dr. Matthew Waugh Rachel Martini Prof. Yong-Su Jin Prof. Yi Lu 《Angewandte Chemie (International ed. in English)》2023,62(5):e202212440
Engineering enzymes with novel reactivity and applying them in metabolic pathways to produce valuable products are quite challenging due to the intrinsic complexity of metabolic networks and the need for high in vivo catalytic efficiency. Triacetic acid lactone (TAL), naturally generated by 2-pyrone synthase (2PS), is a platform molecule that can be produced via microbial fermentation and further converted into value-added products. However, these conversions require extra synthetic steps under harsh conditions. We herein report a biocatalytic system for direct generation of TAL derivatives under mild conditions with controlled chemoselectivity by rationally engineering the 2PS active site and then rewiring the biocatalytic pathway in the metabolic network of E. coli to produce high-value products, such as kavalactone precursors, with yields up to 17 mg/L culture. Computer modeling indicates sterics and hydrogen-bond interactions play key roles in tuning the selectivity, efficiency and yield. 相似文献
898.
899.
5-Arylpyrazine-2,3-dicarbonitriles 1 and 2 give 2-alkylamino-5-arylpyrazine-3-carbonitriles 3 and 5 and 3-alkylamiono-5-arylpyrazine-2-carbonitriles 4 and 6 by the substitution reaction with amines but give only 3-aminopyrazine-2-carbonitrile derivative on the reaction with ammonia. The reaction of 5-arylpyrazine-2,3-dicarbonitriles ( 1 and 2 ) with alcohols in the presence of a base gives 2-alkoxypyrazine-3-carbonitrile derivatives 9 and 13 and 3-alkoxypyrazine-2-carbonitrile derivatives 10 and 14 . The reaction of water gives two pyrazinonecarbonitrile derivatives 11 and 12 . In these reactions the aryl groups on the pyrazine ring are 3,4-dimethoxyphenyl and benzo-15-crown-5. 相似文献
900.