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1.
Uesato S Taniuchi K Kumagai A Nagaoka Y Seto R Hara Y Tokuda H Nishino H 《Chemical & pharmaceutical bulletin》2003,51(12):1448-1450
In the course of an exploratory investigation of antitumor-promoting catechins, 3-O-acyl-(+)-catechins of varying carbon lengths from C(4) to C(18) were assessed for inhibitory effects on the activation of the Epstein-Barr virus early antigen. Like 3-O-acyl-(-)-epigallocatechins, the (+)-catechin derivatives showed promising effects with the C-3 acyl chain of C(8)-C(11) carbon atoms. 相似文献
2.
Hiroshi Maruoka Kenji Yamagata Fumi Okabe Yukihiko Tomioka 《Journal of heterocyclic chemistry》2005,42(4):717-721
A series of cyclic sulfonium ylides 4a‐h reacted with titanium( IV ) chloride in the presence of triethyl‐amine to give the corresponding fused 2,3‐dihydro‐1H‐thieno[3,4‐b]pyrroles 5a‐h , via a ring opening and recyclization. In contrast, treatment of compounds 4a, 4b, 4e and 4f with titanium(IV) chloride, triethy‐lamine and dimethylamine hydrochloride gave the corresponding thiophenes 6a, 6b, 6e and 6f . Furthermore, compounds 6a and 6b easily underwent cyclization with sodium hydride to afford the corresponding 5a and 5b . 相似文献
3.
Air containing particulate material was passed continuously for one month through a low-volume air sampler equipped with a cyclone to exclude particulates greater than 10 μm in diameter. The samples and filters were ashed in a low-temperature plasma and, after addition of In2O3 support, palladium internal standard and graphite buffer, the ashes were analyzed by a.c. are emission spectrometry. Standard samples were prepared from a commercial standard containing 49 elements. The procedure allows the determination of 14 trace metals (Ag, Al, Cr, Cu, Fe, Ga, Mn, Mo, Ni, Pb, Sn, Ti, V, Zn) with relative standard deviations of 1.4–15.1%. The procedure has been applied successfully to monthly determinations of the average atmospheric concentrations of these elements in Kobe City for the past three years. 相似文献
4.
5.
Noritaka Ohtani Yukihiko Inoue Hiroshi Mizuoka Kenya Itoh 《Journal of polymer science. Part A, Polymer chemistry》1994,32(13):2589-2595
Dilute-solution viscosities of polystyrene-based cationic ionomers containing ammonio or phosphonio groups were measured in several solvents. In polar solvents with dielectric constant (εr) beyond 10, the ionomers showed a typical polyelectrolyte behavior, indicating that a large part of ionic groups were dissociated into ions. In nonpolar solvents with low εr, the reduced viscosity of the ionomers linearly decreased with a decreasing ionomer concentration. At low polymer concentrations, every ionomer gave a reduced viscosity lower than that of the corresponding chloromethylated polystyrene. With an increasing ion content, the intrinsic viscosity progressively decreased if the nonpolar solvents had a low acceptor number (AN), such as toluene or tetrahydrofran (THF). In the halogenated solvents with high AN value, such as chloroform, however, the intrinsic viscosity was hardly dependent on the ion content. This indicates that the intramolecular aggregation among the ionic groups is inhibited in the halogenated solvents due to a strong anion solvation. An addition of a protic solvent to a nonpolar solvent eliminates the aggregation between ionic groups and leads to polyelectrolyte behavior. © 1994 John Wiley & Sons, Inc. 相似文献
6.
Bound state pion production in40Ca and120Sn nuclei in (p,2p) and (n,d) reactions is investigated. The differential and total cross sections have been obtained. It is shown that the cross sections are determined by the overlap function of the bound states of the nucleon and pion, and as consequence,s-wave part of the pion-nucleus optical potential. The contributions from the nucleons and deuteron distortions are evaluated.The authors would like to express their gratitude to R.A. Eramzhyan, S.N. Gninenko, V.B. Kopeliovich, V.M. Lobashev, B.B. Matveev and E. Oset for very useful and stimulating discussions. 相似文献
7.
The completely conjugated polymer, polyethynylferrocene, was prepared by heating ethynylferrocene with catalytic amounts of azobisisobutyronitrile to 180-240[ddot] under nitrogen in bulk. Cyclotrimerization competes with polymerization under these conditions. Pure low molecular weight polyethynylferrocene was isolated and characterized by IR and NMR spectroscopy and by a gel permeation chromatography. The pure polymer exhibits a conductivity of 2 × 10?14 ?1 cm?1. Attempts to prepare polyethynylferrocene by heating acetylferrocene in molten zinc chloride were, contrary to literature reports, unsuccessful. A polymer containing hydroxyl and keto groups was obtained, and extensive degradation of the ferrocene groups occurred. The general reaction scheme is discussed. It includes cleavage of cyclopentadienyl rings from ferrocene and the incorporation of cyclopentane rings into the polymer structure. 相似文献
8.
Controlled Dynamic Helicity of a Folded Macrocycle Based on a Bisterephthalamide with a Twofold Z‐Shaped Structure 下载免费PDF全文
Dr. Ryo Katoono Keiichi Kusaka Prof. Dr. Kenshu Fujiwara Prof. Dr. Takanori Suzuki 《化学:亚洲杂志》2014,9(11):3182-3187
Dynamic helicity in a folded macrocycle and control of the helical preference are described. We designed macrocycle 1 with a dual mode of folding through the integration of two flexible units that are arranged twice to form a cyclic structure. As a folding unit, we used a terephthalamide skeleton and a Z‐shaped hydrocarbon: the former acted as a control unit to induce a preference of a particular sense of dynamic helicity and the latter was just a spacer. A terephthalamide unit provided a binding site for capturing a ditopic hydrogen‐bonding guest when it adopted helically folded syn forms (M/P). Thus, only the terephthalamide unit controlled the helical sense of dynamic helicity in a folded macrocycle through the supramolecular transmission of chirality upon complexation with a chiral ditopic guest. In addition, chirality on a host could also contribute to the control of the helical preference in a folded macrocycle, which led to exceptionally enhanced chiroptical signals. 相似文献
9.
Ryuichi Kusaka Shohei Ohgi Kenta Shigemori Tetsuya Fujimoto 《Physical Therapy Research》2008,11(1):15-21
The aims of this study were to analyze 1) whether there was the relationship between the neonatal behavioral characteristics and amount of crying in premature infants at term age, and 2) what kind of difference between infants with high levels of crying and cry less on neonatal behavioral characteristics using the Neonatal Behavioral Assessment Scale (NBAS). The study participants consisted of 69 healthy low birth-weight infants who were admitted to the NICU at the Nagasaki University Hospital, Nagasaki, Japan. This study analyzed the relationship between NBAS scores measured neonatal behavioral performance and crying at term age. This study results indicate that there was significant statistical negative correlation between the amount of total daily crying and Habituation, Range of state, Regulation of state, and Autonomic stability cluster scores and some individual items scores (Response decrement to light, Response decrement to tactile of foot, Alert responsiveness, Examiner persistence, Motor maturity, Irritability, General irritability, Cuddliness, Consolability, Self-quieting activity, and State regulation). The high levels crying group also showed higher responsivity than less crying group in the items of Peak of excitement, Rapidity of build-up, Irritability and General irritability. In conclusion, neonatal behavioral characteristics such as poor inhibit discrete stimuli while asleep, hyper-responsivity and poor state regulation abilities were risk factors of high levels of crying. 相似文献
10.
Kazuhiko Saigo Yukihiko Hashimoto Kazushi Kinbara Atsushi Sudo 《Journal of Chemical Sciences》1996,108(6):555-573
The review describes the mechanism of chiral discrimination of racemic amines upon crystallization and the induction of chirality
in organic reactions by using them as chiral auxiliaries. In order to form conglomerates, which can be resolved into the two
enantiomers upon alternative seeding, both formation and packing of 21-columns are essentially very important. On the other hand, in order to achieve high efficiency in resolution through diastereomeric
salt formation, which is the most practical method, one of a pair of diastereomeric salts derived from a racemic amine and
an enantiomerically pure resolving agent should at least have two 21-columns and planar boundary surfaces in its crystal structure. On the basis of this knowledge, we developed several artificial
chiral auxiliaries such as erythro-2-amino-1,2-diphenylethanol,cis-2-amino-1-acenaphthenol, andcis-2-amino-3,3-dimethyl-1-indanol. These were found to be very efficient chiral auxiliaries in asymmetric inductions: alkylation
of chiral imines, catalytic borane-reduction, and alkylation of chiral N-acylated oxazolidinone. 相似文献