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111.
D Matsumura K Kitazawa S Terai T Kochi Y Ie M Nitani Y Aso F Kakiuchi 《Organic letters》2012,14(15):3882-3885
A convenient method for the synthesis of tetraalkylanthracenes and -pentacenes by means of ruthenium-catalyzed regioselective C-H alkylation of the corresponding acenequinones was developed. Dialkyldiarylpentacene was also synthesized using chemoselective tandem C-H alkylation/C-O arylation of dimethoxypentacenequinone. It was suggested that a tetraalkylpentacene is stable under air in the dark and possesses an appropriate HOMO level as active material for p-type organic field-effect transistors (OFETs). 相似文献
112.
Yamada M Yao I Hayasaka T Ushijima M Matsuura M Takada H Shikata N Setou M Kwon AH Ito S 《Analytical and bioanalytical chemistry》2012,402(5):1921-1930
Direct tissue analysis using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) provides the means
for in situ molecular analysis of a wide variety of biomolecules. This technology—known as imaging mass spectrometry (IMS)—allows
the measurement of biomolecules in their native biological environments without the need for target-specific reagents such
as antibodies. In this study, we applied the IMS technique to formalin-fixed paraffin-embedded samples to identify a substance(s)
responsible for the intestinal obstruction caused by an unidentified foreign body. In advance of IMS analysis, some pretreatments
were applied. After the deparaffinization of sections, samples were subjected to enzyme digestion. The sections co-crystallized
with matrix were desorbed and ionized by a laser pulse with scanning. A combination of α-amylase digestion and the 2,5-dihydroxybenzoic
acid matrix gave the best mass spectrum. With the IMS Convolution software which we developed, we could automatically extract
meaningful signals from the IMS datasets. The representative peak values were m/z 1,013, 1,175, 1,337, 1,499, 1,661, 1,823, and 1,985. Thus, it was revealed that the material was polymer with a 162-Da unit
size, calculated from the even intervals. In comparison with the mass spectra of the histopathological specimen and authentic
materials, the main component coincided with amylopectin rather than amylose. Tandem MS analysis proved that the main components
were oligosaccharides. Finally, we confirmed the identification of amylopectin by staining with periodic acid-Schiff and iodine.
These results for the first time show the advantages of MALDI-IMS in combination with enzyme digestion for the direct analysis
of oligosaccharides as a major component of histopathological samples. 相似文献
113.
Nobuaki Hoshino 《Annals of the Institute of Statistical Mathematics》2012,64(3):457-474
The present article investigates a class of random partitioning distributions of a positive integer. This class is called
the limiting conditional compound poisson (LCCP) distribution and characterized by the law of small numbers. Accordingly the
LCCP distribution explains the limiting behavior of counts on a sparse contingency table by the frequencies of frequencies.
The LCCP distribution is constructed via some combinations of conditioning and limiting, and this view reveals that the LCCP
distribution is a subclass of several known classes that depend on a Bell polynomial. It follows that the limiting behavior
of a Bell polynomial provides new asymptotics for a sparse contingency table. Also the Neyman Type A distribution and the
Thomas distribution are revisited as the basis of the sparsity. 相似文献
114.
Miyaoka H Abe Y Sekiya N Mitome H Kawashima E 《Chemical communications (Cambridge, England)》2012,48(6):901-903
Total synthesis of antimalarial diterpenoid (+)-kalihinol A, isolated from marine sponge Acanthella sp., is achieved. This total synthesis involves regioselective alkylation of an epoxide, construction of a tetrahydropyran ring by iodo-etherification, construction of a cis-decalin ring by intramolecular Diels-Alder reaction, isomerization of cis-decalin to trans-decalin, and subsequent functionalization of the trans-decalin ring. 相似文献
115.
R Shen T Iwasaki J Terao N Kambe 《Chemical communications (Cambridge, England)》2012,48(74):9313-9315
Cu-catalyzed cross-coupling of unactivated secondary alkyl iodides with alkyl Grignard reagents in the presence of 1,3-butadiene as a ligand precursor was developed. The use of 1,3-butadiene resulted in improved yields of alkyl-alkyl products with improved selectivities. 相似文献
116.
Hiromasa Nishikiori Nobuaki Tanaka Tsuneo Fujii 《Research on Chemical Intermediates》2000,26(5):469-482
Dip-coated thin films including rhodamine B have been prepared using the sol-gel reaction of tetraethyl orthosilicate under
relative humidity of 30% and 60%. They have been aged under relative humidity of 20%, 60%, and 95% for 5 days. According to
the absorption spectra, just after the preparation of the films and under higher humidity, a larger amount of the dimers (H-and
J-types) were formed in the films. Five days after the preparation of the films and aged under higher humidity, the H-dimer
increased. On the other hand, the J-dimer increased, regardless of humidity under which the films were aged. 相似文献
117.
118.
Yuzuru Uchida Katsumi Onoue Nobuaki Tada Fumio Nagao Hideaki Kozawa Shigeru Oae 《Heteroatom Chemistry》1990,1(4):295-306
Phosphine oxides bearing two or three 2-pyridyl groups react with organometallic reagents affording 2,2′-bipyridyl, 2-substituted pyridines and pyridine in good yields. Phosphonium salts and phosphine oxides, bearing at least two 2-pyridyl or substituted 2-pyridyl groups also give the corresponding 2,2′-bipyridyls and pyridines upon treatment with acid or neutral solvents such as water and alcohols in substantial yields. The 2,2′-bipyridyls are considered to be formed by ligand coupling within the pentacoordinated phosphorus intermediate formed incipiently during the reaction. 相似文献
119.
The kinetics of the flattening of surface corrugations of float glasses were investigated in dry nitrogen at 610 to 670°C. The amplitude of the sinusoidal surface profile decayed exponentially with time while its wavelength remained constant. The dependence of decay rate on wavelength indicated that the process is controlled by the viscous flow. From the obtained rate constant the viscosity was calculated using the surface energy value determined independently by the zero-creep method. The viscosity thus obtained reflects the mass transport property in the vicinity of the glass surface. It was several times larger than that determined by the fibre elongation or intrusion method which should reflect the bulk properties. No difference in the decay rate was observed on both the surfaces of float glass of which only one side had been exposed to molten tin during the glass manufacturing process. 相似文献
120.