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101.
102.
Young-ah WooChang-hee Cho Hyo-jin Kim Jong-soo YangKi-yong Seong 《Microchemical Journal》2002,73(3):299-306
A rapid and nondestructive near infrared (NIR) method using soft independent modeling of class analogy (SIMCA) for the classification of cultivation area (Korea and China) was evaluated and confirmed. Raw, first, and second derivative NIR spectra were compared to develop a robust classification rule. The chemical properties of ginseng samples were also investigated to find out the differences between Korean samples and Chinese samples. These differences make NIR spectroscopic method viable. The average value of each Korean and Chinese ginseng sample for crude fiber, crude protein, starch, and 10 inorganic constituents were measured and compared with F-test and t-test. The inorganic constituents were also measured by induced coupled plasma-atomic emission spectroscopy (ICP-AES). It could be found that the amount of starch and ten inorganic elements for example Na, Mg, P, K, Ca, Mn, Fe, Ni, Cu and Zn in ginseng samples are considerably different based on cultivation area. SIMCA has been applied to the inorganic data to investigate the possibility of ICP-AES as classification tool. However, it was observed that the result was not equal to than NIR spectra data. The overall results showed the availability of NIR method using SIMCA would be adequate for classification of cultivation of ginseng, since NIR spectra includes useful and various information on chemical properties in spite of broad and overlapped bands. 相似文献
103.
The ruthenium(II) porphyrin fluorophore complexes [Ru(TPP)(CO)(Ds-R)] (TPP = tetraphenylporphinato dianion; Ds = dansyl; R = imidazole (im), 1, or thiomorpholine (tm), 2) were synthesized and investigated for their ability to detect nitric oxide (NO) based on fluorescence. The X-ray crystal structures of 1 and 2 were determined. The Ds-im or Ds-tm ligand coordinates to an axial site of the ruthenium(II) center through a nitrogen or sulfur atom, respectively. Both exhibit quenched fluorescence when excited at 368 or 345 nm. Displacement of the metal-coordinated fluorophore by NO restores fluorescence within minutes. These observations demonstrate fluorescence-based NO detection using ruthenium porphyrin fluorophore conjugates. 相似文献
104.
Photoactivation of pheophorbide a induces a mitochondrial-mediated apoptosis in Jurkat leukaemia cells 总被引:5,自引:0,他引:5
Lee WY Lim DS Ko SH Park YJ Ryu KS Ahn MY Kim YR Lee DW Cho CW 《Journal of photochemistry and photobiology. B, Biology》2004,75(3):119-126
The mechanism of cell death by pheophorbide a (Pba) which has been established to be a potential photosensitizer was examined in experimental photodynamic therapy (PDT) on Jurkat cells, a human lymphoid tumor cell line. In 30-60 min after irradiation, Pba treated cells exhibited apoptotic features including membrane blebbing and DNA fragmentation. Pba/PDT caused a rapid release of cytochrome c from mitochondria into the cytosol. Sequentially, activation of caspase-3 and the cleavage of poly ADP-ribose polymerase (PARP) were followed. Meanwhile, no evidence of activation of caspase-8 was indicated in the cells. In experiments with caspase inhibitors, it was found that caspase-3 alone was sufficient initiator for the Pba-induced apoptosis of the cells. Pba specific emission spectra were confirmed in the mitochondrial fraction and the light irradiation caused a rapid change in its membrane potential. Thus, mitochondria were entailed as the crucial targets for Pba as well as a responsible component for the cytochrome c release to initiate apoptotic pathways. Taken together, it was concluded that the mode of Jurkat cell death by Pba/PDT is an apoptosis, which is initiated by mitochondrial cytochrome c release and caspase-3-pathways. 相似文献
105.
建立了酱油中1,3-二氯-2-丙醇、2,3-二氯-1-丙醇、3-氯-1,2-丙二醇和2-氯-1,3-丙二醇的分散固相萃取-气相色谱-高分辨质谱快速筛查检测方法。样品采用乙酸乙酯提取,提取液浓缩后经N-丙基乙二胺净化,气相色谱-高分辨质谱测定,内标法定量。结果表明,该方法对于酱油中4种氯丙醇的定量限为0.5~10 μg/kg。在3个浓度水平下的加标回收率为78%~103%;相对标准偏差均不大于8.8%。该方法快速、简便、准确、灵敏,可作为酱油中4种氯丙醇的有效检测方法。 相似文献
106.
Moonhor Ree Jong-Seong KimJae Jung Kim Byeang Hyean KimJuyoung Yoon Heesoo Kim 《Tetrahedron letters》2003,44(45):8211-8215
The synthesis of novel cavitands containing four fluorophores [tert-butoxycarbonyl protected 2,2′-bis(furyl)benzidine (t-BOC FurylBz) or 5,5′-bis(4-aminophenyl)-2,2′-bifuryl (t-BOC PFDA)] and ionophoric functional groups on the upper rim is reported. The cavitands bearing the four fluorophores emit blue light photoluminescence. In particular, the cavitand containing PFDA moieties exhibits a high photoluminescence quantum yield. 相似文献
107.
Young-Gu Cho Dae-Kwang Park Dae-Won Park Hee-Chul Woo Jong-Shik Chung 《Research on Chemical Intermediates》2002,28(5):419-431
The selective oxidation of hydrogen sulfide containing excess water and ammonia was studied over vanadium-bismuth mixed oxide catalysts. The investigation was focused on understanding the complex reaction steps and the roles of each metal oxide. Therefore, supported V2O5/TiO2, V-Bi-O/TiO2 catalysts and a mechanical mixture of V2O5 + Bi2O3 were tested in the reaction. Ammonia reacted either with H2S or SO2, produced from the oxidation of H2S. Water vapor promoted the reaction of ammonia and SO2. Strong synergistic phenomena in catalytic activity were observed for the mechanically mixed catalyst of V2O5 and Bi2O3. V-Bi-O/TiO2 catalyst showed very high H2S conversion without any considerable emission of SO2. Temperature-programmed studies (TPR and TPO), XRD and Raman analyses revealed that the high catalytic performance of V-BiO/TiO2 catalyst originated from the high redox capacity of the bismuth vanadate phase. 相似文献
108.
Somatostatin (SST) is a well-known neuropeptide that is expressed throughout the brain. In the cortex, SST is expressed in a subset of GABAergic neurons and is known as a protein marker of inhibitory interneurons. Recent studies have identified the key functions of SST in modulating cortical circuits in the brain and cognitive function. Furthermore, reduced expression of SST is a hallmark of various neurological disorders, including Alzheimer’s disease and depression. In this review, we summarize the current knowledge on SST expression and function in the brain. In particular, we describe the physiological roles of SST-positive interneurons in the cortex. We further describe the causal relationship between pathophysiological changes in SST function and various neurological disorders, such as Alzheimer’s disease. Finally, we discuss potential treatments and possibility of novel drug developments for neurological disorders based on the current knowledge on the function of SST and SST analogs in the brain derived from experimental and clinical studies.Subject terms: Molecular neuroscience, Drug development 相似文献
109.
Surface-conductive particles consisting of a poly(methyl methacrylate) (PMMA) core and a polyaniline (PA)-coated shell were synthesized and adopted as suspended particles for electrorheological (ER) fluids. The PA-PMMA composite particles synthesized were monodisperse and spherical in shape. The PA-PMMA suspensions in silicone oil showed typical ER characteristics under an applied electric field. The PA-PMMA composite particles possess a higher dielectric constant and conductivity than the pure PA particle, within an acceptable conductivity range for ER fluids, but the PA-based ER fluid showed larger shear-stress enhancement than the PA-PMMA-based systems. This phenomena can be explained by the interfacial polarizability of PA-based ER fluids, which is the difference between the ER fluid's dielectric constant and loss factor - this polarizability was higher than that of PA-PMMA-based ER fluids, as shown by the dielectric spectrum of each fluid. The insulating PMMA core suppressed the interfacial polarization in ER fluids, resulting in reduced interaction among particles under an imposed electric field. 相似文献
110.
Chan Sik Cho Tae Kyung Kim Tae‐Jeong Kim Sang Chul Shim Nam Sik Yoon 《Journal of heterocyclic chemistry》2002,39(2):291-294
Nitroarenes are reductively cyclized with 3‐amino‐1‐propanols in dioxane/H2O in the presence of a ruthenium catalyst and tin(II) chloride dihydrate together with isopropanol to afford the corresponding quinolines. A reaction pathway involving initial reduction of nitroarenes to anilines, propanol group transfer from 3‐amino‐1‐propanols to anilines, N‐alkylation of anilines by 3‐anilino‐1‐propanols and heteroannulation of 1,3‐dianilinopropanes is proposed. 相似文献