排序方式: 共有67条查询结果,搜索用时 15 毫秒
41.
Ernesto FattorussoPaolo Luciano Masteria Yunovilsa Putra Orazio Taglialatela-Scafati Angela IanaroElisabetta Panza Giorgio BavestrelloCarlo Cerrano 《Tetrahedron》2011,67(41):7983-7988
Chemical analysis of the Indonesian soft coral Sinularia sp. (order Alcyonacea, family Alcyoniidae) afforded two known and three new C-4 norcembranoids, named chloroscabrolides A (3) and B (4) and prescabrolide (5). Chloroscabrolide A is a pentacyclic norcembranoid including an unprecedented THF-type ring to connect C-13 and C-15; furthermore, it is only the second chlorinated cembranoid derivative to be reported in the literature. The relative configuration of chloroscabrolide A has been established on the basis of a comparison between experimental 13C NMR data and DFT-calculated 13C NMR chemical shifts. All the isolated norcembranoids have been evaluated for iNOS protein inhibition. 相似文献
42.
Miftahussurur Hamidi Putra Sebastian Seidenath Dr. Stephan Kupfer Prof. Dr. Stefanie Gräfe Prof. Dr. Axel Groß 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(68):17104-17114
Conductive polymers represent a promising alternative to semiconducting oxide electrodes typically used in dye-sensitized cathodes as they more easily allow a tuning of the physicochemical properties. This can then also be very beneficial for using them in light-driven catalysis. In this computational study, we address the coupling of Ru-based photosensitizers to a polymer matrix by combining two different first-principles electronic structure approaches. We use a periodic density functional theory code to properly account for the delocalized nature of the electronic states in the polymer. These ground state investigations are complemented by time-dependent density functional theory simulations to assess the Franck-Condon photophysics of the present photoactive hybrid material based on a molecular model system. Our results are consistent with recent experimental observations and allow to elucidate the light-driven redox chemical processes – eventually leading to charge separation – in the present functional hybrid systems with potential application as photocathode materials. 相似文献
43.
Sajan L. Shyaula Mohammad I. Choudhary Mangala D. Manandhar 《Moscow University Chemistry Bulletin》2013,68(6):293-297
The crude ethanolic extract of the Nepalese sandalwood Osyris wightiana Wall. ex Wight, was analyzed for its bioactive chemical constituents by chromatographic and spectroscopic methods. Phenyl propanoid, benzyl alcohol, iridoid and megastiigmanes, were isolated from the butanolic fraction by the successive use of column chromatography and HPLC. They were isolated as the new source from the genus Osyris. The structures of syringin (1) and di-O-methylcrenatin (2), 8-epideoxyloganic acid (3), citroside B (4) and roseoside (5) were characterized on the basis of extensive spectroscopic data analysis of NMR, mass and other spectroscopic techniques. 相似文献
44.
We consider a distance generalisation of the strong chromatic index and the maximum induced matching number. We study graphs of bounded maximum degree and Erd?s–Rényi random graphs. We work in three settings. The first is that of a distance generalisation of an Erd?s–Ne?et?il problem. The second is that of an upper bound on the size of a largest distance matching in a random graph. The third is that of an upper bound on the distance chromatic index for sparse random graphs. One of our results gives a counterexample to a conjecture of Skupień. 相似文献
45.
Shinji Sakai Tetsu Yamaguchi Ryan Anugrah Putra Rie Watanabe Masaaki Kawabe Masahito Taya Koei Kawakami 《Journal of Sol-Gel Science and Technology》2012,61(2):374-380
Electrospun ultrafine silica fibers were calcined at 150–800 °C. The relation of calcination temperature to the ability to
form biomimetic apatite in a simulated body fluid solution (SBF) was evaluated. The largest apatite particles, formed on non-calcined
fibers after 1 week of soaking in SBF, were 10 μm in diameter, had a narrow size distribution (coefficient of variation 9%),
and were similar to pearls on string. The particles size decreased with increasing calcination temperature below 250 °C and
the particles formed on the fibers calcined at 250 °C were 4.5 μm in diameter. No particles were found on those calcined above
500 °C. By using a concentrated SBF at 1.5-times higher ionic concentrations than SBF, the size of apatite microparticles
increased about 50%. The fibrous substrate covered with apatite particles was effective for osteoblastic differentiation of
pre-osteoblastic cells. 相似文献
46.
Syahrul S. Mirmanto M. Sukmawaty S. Putra G. As’ary S. 《Journal of Applied Mechanics and Technical Physics》2021,62(2):230-237
Journal of Applied Mechanics and Technical Physics - An experimental study of a novel dryer is performed. In this current study, paddy drying is carried out using a vertical dryer. The paddy mass... 相似文献
47.
Prof. Dr. Tomoki Ogoshi Yukie Hamada Ryuta Sueto Dr. Yoko Sakata Prof. Dr. Shigehisa Akine Dr. Adhitya Mangala Putra Moeljadi Dr. Hajime Hirao Dr. Takahiro Kakuta Prof. Dr. Tada-aki Yamagishi Prof. Dr. Motohiro Mizuno 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(10):2497-2502
Host–guest complexation has been mainly investigated in solution, and it is unclear how guest molecules access the assembled structures of host and dynamics of guest molecules in the crystal state. In this study, we studied the uptake, release, and molecular dynamics of n-hexane vapor in the crystal state of pillar[5]arenes bearing different substituents. Pillar[5]arene bearing 10 ethyl groups yielded a crystal structure of herringbone-type 1:1 complexes with n-hexane, whereas pillar[5]arene with 10 allyl groups formed 1:1 complexes featuring a one-dimensional (1D) channel structure. For pillar[5]arene bearing 10 benzyl groups, one molecule of n-hexane was located in the cavity of pillar[5]arene, and another n-hexane molecule was located outside of the cavity between two pillar[5]arenes. The substituent-dependent differences in molecular arrangement influenced the uptake, release, and molecular dynamics of the n-hexane guest. The substituent effects were not observed in host–guest chemistry in solution, and these features are unique for the crystal state host–guest chemistry of pillar[5]arenes. 相似文献
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49.
Ponnapalli Mangala Gowri Sri Vedavyasa Srirangaraja Radhakrishnan Bhattar Poreddy Guruva Reddy Yerraballi Rakesh Shaik Jeelani Basha Akella Venkata Subrahmanya Sarma Janaswamy Madhusudana Rao 《Helvetica chimica acta》2009,92(7):1419-1427
An extensive study of metabolites present in Excoecaria agallocha Linn . led to the isolation of three new ent‐labdane‐type diterpenoids, named agallochaexcoerins A–C ( 1 – 3 ), besides three known compounds. The skeleton present in compound 1 is rather unusual, containing of a seven‐membered lactone. The structures were elucidated on the basis of spectroscopic studies and comparison with known related compounds. The isolated compounds 1 – 6 were not active against Raw 264.7 (macrophage‐like), K 562 (leukemia), and COLO 205 (colon) human carcinoma cell lines. 相似文献
50.