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711.
Dr. Joyce C. Leung Dr. Aaron A. Bedermann Prof. Jón T. Njardarson Prof. David A. Spiegel Prof. Graham K. Murphy Dr. Naoto Hama Dr. Barry M. Twenter Dr. Ping Dong Prof. Tatsuya Shirahata Dr. Ivar M. McDonald Dr. Munenori Inoue Dr. Nobuaki Taniguchi Dr. Travis C. McMahon Dr. Christopher M. Schneider Dr. Nancy Tao Prof. Brian M. Stoltz Prof. John L. Wood 《Angewandte Chemie (International ed. in English)》2018,57(7):1991-1994
Described herein is a synthetic strategy for the total synthesis of (±)‐phomoidride D. This highly efficient and stereoselective approach provides rapid assembly of the carbocyclic core by way of a tandem phenolic oxidation/intramolecular Diels–Alder cycloaddition. A subsequent SmI2‐mediated cyclization cascade delivers an isotwistane intermediate poised for a Wharton fragmentation that unveils the requisite bicyclo[4.3.1]decene skeleton and sets the stage for synthesis completion. 相似文献
712.
Yoshihiro Suto Yan Liu Masanobu Taniguchi 《Statistical Inference for Stochastic Processes》2016,19(1):93-110
Interpolation is an important issue for a variety fields of statistics (e.g., missing data analysis). In time series analysis, the best interpolator for missing points problem has been investigated in several ways. In this paper, the asymptotics of a contrast function estimator defined by pseudo interpolation error for stationary process are investigated. We estimate parameters of the process by minimizing the pseudo interpolation error written in terms of a fitted parametric spectral density and the periodogram based on observed stretch. The estimator has the consistency and asymptotical normality. Although the criterion for the interpolation problem is known as the best in the sense of smallest mean square error for past and future extrapolation, it is shown that the estimator is asymptotically inefficient in general parameter estimation, which leads to an unexpected result. 相似文献
713.
714.
Boron Nitride Nanosheets Improve Sensitivity and Reusability of Surface‐Enhanced Raman Spectroscopy
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Qiran Cai Srikanth Mateti Prof. Wenrong Yang Dr. Rob Jones Dr. Kenji Watanabe Prof. Takashi Taniguchi Prof. Shaoming Huang Prof. Ying Chen Dr. Lu Hua Li 《Angewandte Chemie (International ed. in English)》2016,55(29):8405-8409
Surface enhanced Raman spectroscopy (SERS) is a useful multidisciplinary analytic technique. However, it is still a challenge to produce SERS substrates that are highly sensitive, reproducible, stable, reusable, and scalable. Herein, we demonstrate that atomically thin boron nitride (BN) nanosheets have many unique and desirable properties to help solve this challenge. The synergic effect of the atomic thickness, high flexibility, stronger surface adsorption capability, electrical insulation, impermeability, high thermal and chemical stability of BN nanosheets can increase the Raman sensitivity by up to two orders, and in the meantime attain long‐term stability and extraordinary reusability not achievable by other materials. These advances will greatly facilitate the wider use of SERS in many fields. 相似文献
715.
End‐to‐End Self‐Assembly of Semiconductor Nanorods in Water by Using an Amphiphilic Surface Design
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Yuki Taniguchi Takao Takishita Prof. Tsuyoshi Kawai Dr. Takuya Nakashima 《Angewandte Chemie (International ed. in English)》2016,55(6):2083-2086
One‐dimensional (1D) self‐assemblies of nanocrystals are of interest because of their vectorial and polymer‐like dynamic properties. Herein, we report a simple method to prepare elongated assemblies of semiconductor nanorods (NRs) through end‐to‐end self‐assembly. Short‐chained water‐soluble thiols were employed as surface ligands for CdSe NRs having a wurtzite crystal structure. The site‐specific capping of NRs with these ligands rendered the surface of the NRs amphiphilic. The amphiphilic CdSe NRs self‐assembled to form elongated wires by end‐to‐end attachment driven by the hydrophobic effect operating between uncapped NR ends. The end‐to‐end assembly technique was further applied to CdS NRs and CdSe tetrapods (TPs) with a wurtzite structure. 相似文献
716.
Shoma Mizutani Kenta Komori Prof. Dr. Tohru Taniguchi Prof. Dr. Kenji Monde Prof. Dr. Kouji Kuramochi Prof. Dr. Kazunori Tsubaki 《Angewandte Chemie (International ed. in English)》2016,55(33):9553-9556
A biomimetic synthesis of naturally occurring lactams rubrobramide, flavipucine, and isoflavipucine is described. The key step is a regioselective Darzens reaction between isobutyl glyoxal and an α‐bromo‐β‐ketoamide. The construction of the core tricyclic ring system of rubrobramide was achieved by a cascade reaction in a single step from an α,β‐epoxy‐γ‐lactam. Furthermore, the absolute configuration of naturally occurring (+)‐rubrobramide was determined by vibrational circular dichroism. (±)‐Flavipucine and (±)‐isoflavipucine were synthesized from an epoxyimide, which was prepared by reaction of isobutyl glyoxal with a protected α‐bromo‐β‐ketoamide. Deprotection of the epoxyimide and formation of the pyridone ring gave (±)‐flavipucine, which was converted into (±)‐isoflavipucine by thermal isomerization. 相似文献
717.
Eunkyung Yang Nuonuo Zhang Michael Krayer Masahiko Taniguchi James R. Diers Christine Kirmaier Jonathan S. Lindsey David F. Bocian Dewey Holten 《Photochemistry and photobiology》2016,92(1):111-125
Understanding the effects of substituents on spectral properties is essential for the rational design of tailored bacteriochlorins for light‐harvesting and other applications. Toward this goal, three new bacteriochlorins containing previously unexplored conjugating substituents have been prepared and characterized. The conjugating substituents include two positively charged species, 2‐(N‐ethyl 2‐quinolinium)vinyl‐ (B‐1) and 2‐(N‐ethyl 4‐pyridinium)vinyl‐ (B‐2), and a neutral group, acroleinyl‐ (B‐3); the charged species resemble cyanine (or styryl) dye motifs whereas the neutral unit resembles a merocyanine dye motif. The three bacteriochlorins are examined by static and time‐resolved absorption and emission spectroscopy and density functional theoretical calculations. B‐1 and B‐2 have Qy absorption bathochromically shifted well into the NIR region (822 and 852 nm), farther than B‐3 (793 nm) and other 3,13‐disubstituted bacteriochlorins studied previously. B‐1 and B‐2 have broad Qy absorption and fluorescence features with large peak separation (Stokes shift), low fluorescence yields, and shortened S1 (Qy) excited‐state lifetimes (~700 ps and ~100 ps). More typical spectra and S1 lifetime (~2.3 ns) are found for B‐3. The combined photophysical and molecular‐orbital characteristics suggest the altered spectra and enhanced nonradiative S1 decay of B‐1 and B‐2 derive from excited‐state configurations in which electron density is shifted between the macrocycle and the substituents. 相似文献
718.
K. Takamiya R. Okumura N. Abe Y. Nakano K. Miyata S. Fukutani A. Taniguchi H. Yamana 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(3):719-721
The new control system of pneumatic transportation apparatuses for neutron irradiation in Kyoto University Reactor (KUR) has
been developed based on the TCP/IP network for the purpose of integrated management of the apparatus. The control system is
comprised of PLCs, control PCs, database and web servers. Archiving logs of detailed information about irradiation enables
the secure operation and management of the irradiation system. The information stored in the server can be referred by remote
PCs and mobile phones through the internet. Combining the present facility with measurement and radiation management systems
it can realize advanced INAA methods and secure managements of radioisotopes. 相似文献
719.
Taniguchi T Fukuba TA Nakatsuka S Hayase S Kawatsura M Uno H Itoh T 《The Journal of organic chemistry》2008,73(10):3875-3884
Candida antarctica lipase B (CAL-B) is one the most frequently used enzymes in organic synthesis for the preparation of optically active alcohols. However, it has not been used for the optical resolution of (+/-)-2,2'-binaphthol. We established an efficient linker-oriented design of 2,2'-binaphthol derivatives that is appropriate for optical resolution using CAL-B-catalyzed hydrolysis reaction. Methyl 4-(1-(6-bromo-2-methoxymethoxynaphthalen-1-yl)-6-bromonaphthalen-2-yloxy)butanoate was hydrolyzed by CAL-B to afford a corresponding acid with excellent enantioselectivity ( E > 200). Two types of optically active binaphthol derivatives, 1-(2-hydroxy-6-(naphthalen-1-yl)naphthalen-1-yl)-6-(naphthalen-1-yl)naphthalen-2-ol and 6-butyl-1-(6-butyl-2-hydroxynaphthalen-1-yl)naphthalen-2-ol, were prepared by this chemo-enzymatic reaction protocol and were used as chiral templates for symmetric reactions. 相似文献
720.
Tsuyoshi Taniguchi 《Tetrahedron》2008,64(37):8773-8779
A total synthesis of (±)-stemonamide and (±)-isostemonamide has been achieved by using a radical cascade that involves two endo-selective cyclizations. (±)-Stemonamine and (±)-isostemonamine are synthesized by chemoselective reduction of (±)-stemonamide and (±)-isostemonamide, respectively. 相似文献