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11.
Okada T Komatsu K Kawamoto T Yamanaka T Kagi H 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(10):2423-2427
In situ Raman spectroscopic measurements of water in the region of OH vibration were conducted up to 0.4 GPa at 23 and 52 degrees C. The frequencies of the decomposed OH stretching bands initially decreased with increasing pressure, reached a minimum at 0.15 GPa and increased up to 0.3 GPa and then decreased, which corresponds to the variations of the strength of hydrogen bonding. This variation was observed at 23 degrees C, but not at 52 degrees C, which suggests a change in pressure dependence on the hydrogen bond interaction between these two temperatures. Based on the equilibration model between hydrogen-bonded and nonhydrogen-bonded molecules, the present experimental results indicate that the pressure variation of the viscosity depends on the ratio of hydrogen-bonded molecules, rather than the strength of hydrogen bonding between molecules. 相似文献
12.
The title sterically crowded di-9-anthrylethyne derivative with 3,5-iPr2-phenyl groups at 1-position showed a barrier to rotation about the acetylenic axis of 18.0 kcal mol−1 based on a dynamic NMR study, which is an extremely high value for acyclic diarylethynes. The mechanism of the dynamic stereochemistry and the substituent effect on the rotational barrier are discussed. 相似文献
13.
E Makino N Iwasaki N Yagi T Ohashi H Kato Y Ito H Azuma 《Chemical & pharmaceutical bulletin》1990,38(1):201-207
Various pyrazine derivatives were synthesized and their antiallergic activity was examined. The inhibitory activity on allergic histamine release of the compounds bearing a 5-tetrazolyl group was more potent than that of the corresponding carboxyl derivatives. The introduction of -CONH- or -NHCO- between the pyrazine ring and the 5-tetrazolyl group as a spacer greatly enhanced the activity. N-(1H-Tetrazol-5-yl)-2-pyrazinecarboxamide (I-3) was estimated to exhibit nearly the same potency as disodium cromoglycate (DSCG). The structure-activity relationship among various derivatives modified by introducing some substituents onto the 3-, 5- or 6-position of the pyrazine ring of I-3 was investigated. The activity remained unchanged or was reduced when such substituents as methyl, chloro, methoxy, methylamino and dimethylamino were introduced at the 3- or 5-position. In contrast, 6-substitution with various alkylamino groups more or less increased the activity. Among them, the 6-dimethylamino (I-17c) and 6-(1-pyrrolidinyl) (I-34) derivative were proved to be most potent. The IC50 values (concentration which produces 50% inhibition of the allergic histamine release) of I-17c and I-34 were determined to be 4.7 x 10(-10) and 4.6 x 10(-10) M, respectively. These two compounds produced a potent inhibitory activity on passive cutaneous anaphylaxis (PCA) in rat, not only by the intravenous route (ED50 = 0.0096 mg/kg for both compounds) but also by the oral route (ED50 = 0.19 and 0.18 mg/kg, respectively). On the other hand, when the pyrazine ring of some representative compounds was replaced with a pyridine ring, the inhibitory activity on histamine release was significantly reduced. 相似文献
14.
A capillary electrophoretic method for the simultaneous determination of sulfamethoxazole and trimethoprim in plasma was developed. Sulfamethoxazole and trimethoprim extracted from human plasma with ethyl acetate were analyzed at 20 kV and 25 degrees C using 15 mm phosphate buffer (pH 6.2) as the electrolyte. The detection was by UV at 220 nm. The run time was 8.0 min and the limit of quantification was 10.00 microg/mL for sulfamethoxazole and 2.00 microg/mL for trimethoprim. The recovery was >99% for both compounds. This method enabled the detection of sulfamethoxazole and trimethoprim in plasma of patients after oral ingestion of their combined formulation. The present simple and rapid method is applicable to drug monitoring in immunocompromised patients who are taking the combined formulation of these compounds for the treatment or prophylaxis of Pneumocystis carinii pneumonia. 相似文献
15.
16.
Akchurin N Langland J Onel Y Bonner BE Corcoran MD Cranshaw J Nessi-Tedaldi F Nessi M Nguyen C Roberts JB Skeens J White JL Bravar A Giacomich R Penzo A Schiavon P Zanetti A Bystricky J Lehar F de Lesquen A van Rossum L Cossairt JD Read AL Derevschikov AA Matulenko YA Meschanin AP Nurushev SB Patalakha DI Rykov VL Solovyanov VL Vasiliev AN Grosnick DP Hill DA Laghai M Lopiano D Ohashi Y Shima T Spinka H Stanek RW Underwood DG Yokosawa A Funahashi H Goto Y Imai K Itow Y Makino S Masaike A 《Physical review D: Particles and fields》1993,48(7):3026-3036
17.
Takahiro Makino Kimihiko Kato Hiroyuki Lyozumi Hiroe Honzawa Yoshiaki Tachiiri Mitsuo Hiramatsu † 《Photochemistry and photobiology》1996,64(6):953-956
Abstract— Ultraweak luminescence generated by sweet potato and nonpathogenic Fusarium oxysporum interactions associated with a defense response was detected by a photoncounting method using ultrahigh-sensitive photodetectors. The time-dependent intensity variation, the spectrum and the two-dimensional imaging of the ultraweak luminescence are indicative of the defense response of the sweet potato to F. oxysporum. The production of ipomeamarone as a phytoalexin means that F. oxysporum induced the defense response in the sweet potato. 相似文献
18.
Qi ZM Matsuda N Santos J Yoshida T Takatsu A Kato K 《Journal of colloid and interface science》2004,271(1):249-253
Broadband, time-resolved optical waveguide (OWG) spectroscopy has been used for in situ, real-time investigation into the self-assembly of metal nanoparticle monolayers. The OWG spectroscopy makes it possible to use the transverse electric (TE) and transverse magnetic (TM) modes to measure surface plasmon absorption of immobilized metal nanoparticles in two directions, parallel and normal to the waveguide surface. Therefore, this technique can provide direction-dependent information on the metal nanoparticles at the interface. In this paper, a 50-microm-thick glass plate was used as a slab waveguide and the kinetics of Au nanoparticle adsorption on a hemoglobin-functionalized glass substrate was examined in the early stage of self-assembly. The findings show that with the TE mode the surface plasmon resonance (SPR) behavior for immobilized Au nanoparticles is different from that with the TM mode. 相似文献
19.
Sugimoto K Nishida M Otsuka M Makino K Ohkubo K Mori Y Morii T 《Chemistry & biology》2004,11(4):475-485
Real-time observation of messenger molecules in individual intact cells is essential for physiological studies of signaling mechanisms. We have developed a novel inositol 1,4,5-trisphosphate (IP(3)) sensor based on the pleckstrin homology (PH) domain from phospholipase C (PLC) delta. The environmentally sensitive fluorophore 6-bromoacetyl-2-dimethyl-aminonaphtalene was conjugated to the genetically introduced cysteine at the mouth of the IP(3) binding pocket for enhanced IP(3) selectivity and for rapid and direct visualization of intracellular IP(3) > or = 0.5 microM as fluorescence emission decreased. The probe, tagged with arginine-rich sequences for efficient translocation into various cell types, revealed a major contribution of Ca2+ influx to PLC-mediated IP(3) production that boosts Ca2+ release from endoplasmic reticulum. Thus, our IP(3) probe was extremely effective to quantitatively assess real-time physiological IP(3) production via those pathways formed only in the intact cellular configuration. 相似文献
20.
A model is presented for the potential distribution across a charged membrane. The membrane-fixed charges are assumed to be distributed through a surface layer of non-zero thickness on the membrane. We treat the surface layer as a different phase from the surrounding solution phase. The potential arises from the membrane-fixed charges and from different solubilities of positive and negative electrolyte ions in the two phases. Equations are presented for the potential distribution, which involve the partition coefficients of electrolyte ions and the relative permittivity of the surface layer. 相似文献