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991.
Dr. Deepak Koirala Prakash Shrestha Tomoko Emura Kumi Hidaka Shankar Mandal Prof. Dr. Masayuki Endo Prof. Dr. Hiroshi Sugiyama Prof. Dr. Hanbin Mao 《Angewandte Chemie (International ed. in English)》2014,53(31):8137-8141
While single‐molecule sensing offers the ultimate detection limit, its throughput is often restricted as sensing events are carried out one at a time in most cases. 2D and 3D DNA origami nanostructures are used as expanded single‐molecule platforms in a new mechanochemical sensing strategy. As a proof of concept, six sensing probes are incorporated in a 7‐tile DNA origami nanoassembly, wherein binding of a target molecule to any of these probes leads to mechanochemical rearrangement of the origami nanostructure, which is monitored in real time by optical tweezers. Using these platforms, 10 pM platelet‐derived growth factor (PDGF) are detected within 10 minutes, while demonstrating multiplex sensing of the PDGF and a target DNA in the same solution. By tapping into the rapid development of versatile DNA origami nanostructures, this mechanochemical platform is anticipated to offer a long sought solution for single‐molecule sensing with improved throughput. 相似文献
992.
Mitsuhiro Okimoto Takashi Yoshida Masayuki Hoshi Kazuyuki Hattori Masashi Komata Kenta Tomozawa 《合成通讯》2013,43(19):3320-3328
Several ketone allylhydrazones were electrochemically oxidized in methanol in the presence of sodium methoxide and potassium iodide to afford the corresponding azines. The electro-oxidation involves formation of a new carbon–nitrogen double bond between an allylic carbon atom and the nitrogen atom of a hydrazone to afford a conjugated system. Optimal yields were obtained when 0.5 equivalents of sodium methoxide and a catalytic amount of potassium iodide were used as the supporting electrolyte at room temperature. Presumably, the electro-oxidation involves a two-electron oxidation process where the iodide ion functions as electron carrier. 相似文献
993.
Kultida Songsurang Azusa Miyagawa Mohd Edeerozey Abd Manaf Panitha Phulkerd Shogo Nobukawa Masayuki Yamaguchi 《Cellulose (London, England)》2013,20(1):83-96
The out-of-plane birefringence and its wavelength dispersion are studied employing solution-cast films of cellulose triacetate (CTA). In solution-cast process, CTA molecules are induced to align in the film plane. Although refractive index is the lowest in the oriented direction for the CTA films stretched more than 110 %, refractive index is found to be the lowest in the normal direction for the unstretched cast film. Attenuated total reflection measurements reveal that in-plane alignment of the acetyl group which provides strong polarizability anisotropy is responsible for the phenomenon. Furthermore, the out-of-plane birefringence is found to increase with increasing wavelength, i.e. extraordinary wavelength dispersion, whereas a stretched CTA film shows ordinary wavelength dispersion. The level of the out-of-plane birefringence in cast films depends on the preparation conditions, which is predictable considering the evaporation rate. Moreover, it is demonstrated for the first time that the out-of-plane birefringence and its wavelength dispersion can be modified by addition of a certain plasticizer such as tricresyl phosphate (TCP). During the evaporation, TCP molecules orient in the film plane accompanying the orientation of CTA chains by intermolecular orientation correlation, called nematic interaction. This technique will widen the scope of material design of retardation films because there are numerous liquid compounds having strong polarizability anisotropy. 相似文献
994.
Christina J. Matheny Michael C. Wei Michael C. Bassik Alicia J. Donnelly Martin Kampmann Masayuki Iwasaki Obdulio Piloto David E. Solow-Cordero Donna M. Bouley Rachel Rau Patrick Brown Michael T. McManus Jonathan S. Weissman Michael L. Cleary 《Chemistry & biology》2013,20(11):1352-1363
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995.
Minoru Nagata Tsuyoshi Kiyotsukuri Taizou Hasegawa Naoto Tsutsumi Wataru Sakai 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):965-973
Abstract Network copolyesters were made from adipic acid and ethylene glycol with 10–40 mol% trimesic acid (Y). Prepolymers prepared by melt polycondensation were cast from dimethylformamide solution and postpolymerized at 260°C for various times to form a network. The degree of reaction (D R), estimated from the infrared absorbance of hydroxyl and methylene groups, increased with increasing postpolymerization time and leveled out at about 90% after 4–6 hours. Heat distortion temperatures (T h) measured by thermomechanical analysis increased greatly from ?83 to 48°C upon the incorporation of Y. Wide-angle x-ray diffraction patterns showed that the copolymer films are amorphous. Density, tensile strength, and Young's modulus decreased for the copolymers with 10–30 mol% Y, whereas they increased drastically for the copolymer with 40 mol% Y. The enzymatic degradation was estimated by the weight loss of the copolymer films in buffer solutions with a lipase at 37°C. The weight loss decreased remarkably with increasing Y and showed no weight loss for the copolymer with 40 mol% Y. On the other hand, the weight loss by alkali hydrolysis increased for the copolymers with 10 and 20 mol% Y, implying a difference in the degradation mechanism between enzymatic degradation and alkali hydrolysis. 相似文献
996.
Koji Numasawa Kenjiro Hanaoka Naoko Saito Yoshifumi Yamaguchi Takayuki Ikeno Honami Echizen Masahiro Yasunaga Toru Komatsu Tasuku Ueno Masayuki Miura Tetsuo Nagano Yasuteru Urano 《Angewandte Chemie (International ed. in English)》2020,59(15):6015-6020
Folate receptors (FRs) are membrane proteins involved in folic acid uptake, and the alpha isoform (FR‐α) is overexpressed in ovarian and endometrial cancer cells. For fluorescence imaging of FRs in vivo, the near‐infrared (NIR) region (650–900 nm), in which tissue penetration is high and autofluorescence is low, is optimal, but existing NIR fluorescent probes targeting FR‐α show high non‐specific tissue adsorption, and require prolonged washout to visualize tumors. We have designed and synthesized a new NIR fluorescent probe, FolateSiR‐1 , utilizing a Si‐rhodamine fluorophore having a carboxy group at the benzene moiety, coupled to a folate ligand moiety through a negatively charged tripeptide linker. This probe exhibits very low background fluorescence and afforded a tumor‐to‐background ratio (TBR) of up to 83 in FR‐expressing tumor‐bearing mice within 30 min. Thus, FolateSiR‐1 has the potential to contribute to the research in the field of biology and the clinical medicine. 相似文献
997.
Akira Hasegawa Takatoshi Murase Masayuki Ogawa Hideharu Ishida Makoto Kiso 《Journal of carbohydrate chemistry》2013,32(4):429-439
ABSTRACT 7-O-, 7,9-Di-O-, and 7,8,9-tri-O-acetyl derivatives of N-acetyl-neuraminic acid were synthesized starting from benzyl [2-(trimethylsilyl)-ethyl 5-acetamido-3,5-dideoxy-8,9-O-isopropylidene-D-glycero-α-D-galacto-2-nonulopyranosid]onate (1). 相似文献
998.
Takashi Toyao Masayuki Minakata Kazushi Iyatani Afshin Ebrahimi Po-Chou Chen Chung-Bo Tsai Yu Horiuchi Masaya Matsuoka Masakazu Anpo 《Research on Chemical Intermediates》2013,39(1):415-424
A visible-light-responsive TiO2 thin film (Vis-TiO2), possessing a unique columnar structure oriented perpendicular to the substrate, has been prepared by using a radio-frequency magnetron sputtering deposition method. The unique TiO2 thin film was used as a key component of N719 dye-sensitized solar cells (DSSCs). The rough morphology caused by the columnar structure leads to enhanced photovoltaic performances of these DSSCs as a consequence of increased amounts of adsorbed dyes and facilitated diffusion of the electrolyte into Vis-TiO2 film. Additionally, photovoltaic performances of the DSSCs were found to depend strongly on the thickness of the Vis-TiO2 film, which can be readily controlled by adjusting the sputtering time conducted for deposition. Consequently, a solar-to-electric energy conversion efficiency of 2.6 % under AM 1.5 illumination was observed for an optimally performing DSSC that has a Vis-TiO2 film thickness of 6.9 μm, prepared by employing a sputtering time of 700 min. 相似文献
999.
Naka Koyata Tsuyoshi Miura Yoko Akaiwa Hisashi Sasaki Rie Sato Takuya Nagai Hirohisa Fujimori Takuya Noguchi Masayuki Kirihara Nobuyuki Imai 《Tetrahedron: Asymmetry》2009,20(17):2065-2071
(R)-(+)-Cibenzoline (95% ee) was synthesized in two steps from (+)-2,2-diphenylcyclopropylmethanol 3a (98% ee), which was oxidized with IBX in DMSO, followed by treatment with ethylenediamine in the presence of I2 and K2CO3 in tBuOH. Compound (R)-(+)-3a (98% ee) was prepared by cyclopropanation of 3,3-diphenyl-2-propen-1-ol 1 with Et2Zn and CH2I2 in the presence of a catalytic amount of (S)-2-(methanesulfonyl)amino-1-(p-toluenesulfonyl)amino-3-phenylpropane 2, followed by esterification with 3,5-dinitorobenzoyl chloride, recrystallization, and hydrolysis. 相似文献
1000.