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901.
Niimi K Shinamura S Osaka I Miyazaki E Takimiya K 《Journal of the American Chemical Society》2011,133(22):8732-8739
A novel highly π-extended heteroarene with eight fused aromatic rings, dianthra[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DATT), was selectively synthesized via a newly developed synthetic strategy, fully characterized by means of single crystal X-ray structural analysis, and examined as an organic semiconductor in thin film transistors. Even with its highly extended acene-like π-system, DATT is a fairly air-stable compound with IP of 5.1 eV. Single crystal X-ray structural analysis revealed its planar molecular structure and the lamella-like layered structure with typical herringbone packing. Theoretical calculations of the solid state electronic structure based on the bulk single crystal structure suggest that DATT affords almost comparable intermolecular orbital couplings between HOMOs (t(HOMO)) with those of dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT), implying its good potential as an organic semiconductor for organic field-effect transistors. In fact, field-effect mobilities as high as 3.0 cm(2) V(-1) s(-1) were achieved with vapor-processed DATT-based devices, which is comparable with that of DNTT-based devices. The molecular ordering of DATT in the thin film state, however, turned out to be not completely uniform; as elucidated by in-plane and out-of-plane XRD measurements, the face-on molecular orientation was contaminated in the edge-on orientation, the former of which is not optimal for efficient carrier transport and thus could limit the mobility. 相似文献
902.
Ohta K Sadayama S Togo A Higashi R Tanoue R Nakamura K 《Micron (Oxford, England : 1993)》2012,43(5):612-620
The beam deceleration (BD) method for scanning electron microscopes (SEM) also referred to as "retarding" was applied to back-scattered electron (BSE) imaging of the flat block face of a resin embedded biological specimen under low accelerating voltage and low beam current conditions. BSE imaging was performed with 0-4 kV of BD on en bloc stained rat hepatocyte. BD drastically enhanced the compositional contrast of the specimen and also improved the resolution at low landing energy levels (1.5-3 keV) and a low beam current (10 pA). These effects also functioned in long working distance observation, however, stage tilting caused uncorrectable astigmatism in BD observation. Stage tilting is mechanically required for a FIB/SEM, so we designed a novel specimen holder to minimize the unfavorable tilting effect. The FIB/SEM 3D reconstruction using the new holder showed a reasonable contrast and resolution high enough to analyze individual cell organelles and also the mitochondrial cristae structures (~5 nm) of the hepatocyte. These results indicate the advantages of BD for block face imaging of biological materials such as cells and tissues under low-voltage and low beam current conditions. 相似文献
903.
Hidefumi Hirai Katsuma Hiraki Isamu Noguchi Shoji Makishima 《Journal of polymer science. Part A, Polymer chemistry》1970,8(1):147-156
ESR spectra of homogeneous catalyst systems derived from n-butyl titanate and triethylaluminum at Al/Ti molar ratios of 1.0–10 were observed in toluene solution at several temperatures from ?78°C to +25°C. In the whole range of Al/Ti molar ratios, a single signal with a g value of 1.951 was observed at ?78°C and was associated with the first reaction intermediate. With increasing temperature, the intensity of the signal decreased gradually, while two series of signals appeared, depending on the Al/Ti molar ratio. At an Al/Ti molar ratio of 1.7, seven kinds of signals with g values of 1.960, 1.946, 1.950, 1.959, 1.980, 1.977, and 1.978, respectively, were observed. On the other hand, four kinds of signals with g values of 1.934, 1.966, 1.952, and 1.979, respectively, were found at Al/Ti molar ratios larger than 3. The structures of the species corresponding to the signals were discussed on the basis of the ESR spectra, the order of their growth and their hyperfine structures being considered. Two series of ESR signal were correlated to two kinds of active species for polymerization of styrene and butadiene, respectively. 相似文献
904.
K Miyamoto N Kishi R Koshiura T Yoshida T Hatano T Okuda 《Chemical & pharmaceutical bulletin》1987,35(2):814-822
905.
Gas chromatographic-mass spectrometric determination of macrolide antibiotics in beef and pork using single ion monitoring 总被引:1,自引:0,他引:1
A gas chromatographic-mass spectrometric (GC-MS) method using single ion monitoring (SIM) is described for the determination of residual macrolide antibiotics, oleandomycin, kitasamycin, spiramycin and tylosin, in beef and pork. For GC-MS determination, oleandomycin is acid hydrolysed to desoleandomycin and acetylated, in the same way as erythromycin. However, for elution from a GC column, the carbon-carbon double bonds in the antibiotics must be hydrogenated to single bonds before acid hydrolysis. Kitasamycin and spiramycin are therefore converted into hydroforocidine acetate and tylosin into hydro-O-mycaminosyl tylonolide acetate, which are determined by GC-MS with SIM. 相似文献
906.
Two new ternary chromium sulfides, Ba3CrS5, and Ba3Cr2S6 were synthesized by the reaction of sulfur, barium sulfide, and chromium metal under a high pressure of 5 GPa at 1200°C. Ba3CrS5 crystallized in the hexagonal space group P63cm (No. 185) with a=9.1208(3) Å, c=6.1930(3) Å, V=446.17(3) Å3, and Z=6. It had a column structure with one-dimensional chains of [CrS3]∞ composed of face-sharing CrS6 octahedra surrounded with Ba2+ ions. Additional S columns surrounded with Ba ions were running along with the CrS6 columns. Ba3Cr2S6 crystallized in the trigonal space group R-3c (No. 167) with a=11.8179(7) Å, c=12.796(1) Å, V=1547.7(2) Å3, and Z=6. The structure of Ba3Cr2S6 also contains [CrS3]∞ chains but the chains are composed of octahedral and trigonal prismatic CrS6 units, which are alternately stacked in a face-sharing manner. The formal charges of Cr ions in Ba3CrS5 and Ba3Cr2S6 are 4+ and 3+, respectively. 相似文献
907.
J Kinjo K Araki K Fukui H Higuchi T Ikeda T Nohara Y Ida N Takemoto M Miyakoshi J Shoji 《Chemical & pharmaceutical bulletin》1992,40(12):3269-3273
Six new triterpenoid glycosides called julibrosides A1-A4, B1 and C1 were isolated from Albizziae Cortex, the dried stem bark of Albizzia julibrissin Durazz. Their structures were determined based on spectral and chemical evidence. Julibrosides B1 and C1 had new sapogenols, designated julibrogenin B and C, respectively, while julibrosides A3 included N-acetyl-D-glucosamine as a sugar component. 相似文献
908.
Suzuki Yoshimasa Shoji Ryosuke Tsurumaki Takahiro Tamaki Syohei Nakashima Kousei Miyazu Susumu Yoshikawa Natsuki Ishii Hideki Nogawa Norio Nonaka Masanori Suzuki Kazuki Harada Naoki 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(7):3167-3173
Journal of Radioanalytical and Nuclear Chemistry - The reasons why rice 137Cs concentrations increase near the water inlet were investigated using rectangular experimental plots settled in paddy... 相似文献
909.
Takao Shoji Dr. Shokaku Kim Prof. Kazuhiro Chiba 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(14):4069-4072
Azanucleosides, in which the 4′‐oxygen atom has been replaced with a nitrogen atom, have drawn much attention owing to their anticancer and antivirus activity, and tolerance towards nucleases. However, the traditional synthetic strategy requires multiple steps and harsh conditions, thereby limiting the structural and functional diversity of the products. Herein we describe the synthesis of azanucleosides by an electrochemical reaction in a lithium perchlorate–nitroethane medium, followed by postmodification at the 4′‐N position. N ‐Acryloyl prolinol derivatives were converted into azanucleosides by anodic activation of the N ‐α‐C−H bond. Moreover, the use of nitroethane instead of nitromethane lowered the oxidation potential of the N ‐acryloyl prolinols and increased the Faradic yield. The prepared azanucleosides were efficiently functionalized at the 4′‐N ‐acryloyl group with a lipophilic alkanethiol and a fluorescent dye by conjugate addition and olefin cross‐metathesis, respectively. 相似文献
910.
为寻找镍(Ni)新型解毒剂,小鼠腹腔注射氯化镍溶液(5 mg Ni/kg),观察二乙氨基二硫代甲酸钠(DDTC),二羟乙氨基二硫代甲酸钠(DHED),N-苯甲基-D-葡糖氨基二硫代甲酸钠(BGD),meso-2,3-二巯基丁二酸钠(DMSA)及环己烷二胺四乙酸钠(CDTA)等螯合剂对镍致小鼠肾脏毒性的解毒作用。镍染毒引起小鼠肾脏脂质过氧化(LPO)和钙、铁及锌浓度增加,血清肌酐及血液尿素氮(BUN)升高。镍染毒30分钟和24小时后进行各螯合剂治疗(剂量均为400 μmol/kg 相似文献