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排序方式: 共有496条查询结果,搜索用时 15 毫秒
101.
102.
N Yabuki H Sasano M Tobita A Imatani T Hoshi K Kato S Ohara S Asaki T Toyota H Nagura 《Canadian Metallurgical Quarterly》1997,151(3):821-829
Helicobacter pylori (HP) infection, a cause of multifocal atrophic gastritis, is considered an important factor related to the evolution of the human gastric mucosa from normal to intestinal-type adenocarcinoma. We examined cell proliferation and both double and single strand DNA damage in situ in 35 patients undergoing gastrectomy for adenocarcinoma with HP-infected gastric mucosa by immunolocalization of Ki-67, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling, and in situ nick translation. We also studied the distribution of intraepithelial neutrophils by elastase immunolocalization. HP infection was confirmed in all cases by serum anti-HP antibodies, ureas testing, and histopathological examination. HP-infected gastric mucosa was classified according to the degree of inflammation and intestinal metaplasia. Ki-67, terminal deoxynucleotidyl transferase-mediated labeling, in situ nick translation, and intraepithelial neutrophil indices all increased with the progression of gastritis and were highest in glands with incomplete intestinal metaplasia. All indices were lowest in gastric glands with complete intestinal metaplasia. Significant positive correlations were observed among these markers. Increased proliferative activity in HP-associated chronic gastritis in response to cell damage or injury was clearly demonstrated, suggesting that both HP-associated toxins and intraepithelial neutrophils are important in HP-related gastric epithelial injury. Increased cell turnover associated with incomplete intestinal metaplasia may result in DNA instability and subsequent development of intestinal-type gastric adenocarcinoma in HP-infected mucosa. 相似文献
103.
104.
Taichi Miura Yuichi Hatsukawa Hisakazu Muramatsu Hiromichi Nakahara 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1985,9(2):123-126
Mean ranges of 119Sb in tin and 125I in copper have been measured for the energy region of 10 keV to 60 keV by using the samples prepared by ion-implantation of these nuclides into vacuum-evaporated layers of metals. The observed ranges are in good agreement with those predicted by the theory of Lindhard et al. for 0.1 > ? > 0.02, but they are slightly smaller for 0.02 > ? > 0.01 in terms of the dimensionless energy ?. 相似文献
105.
A Toyota T Shima M Nishida K Yamane Y Okada L Csiba J Kollár J Sikula 《Canadian Metallurgical Quarterly》1997,49(7):633-637
BACKGROUND: Photodynamic therapy (PDT) is a method for local and selective tumour destruction achieved by the action of light on a photosensitizing drug. METHODS: We investigated the distribution of 5-amino-laevulinic acid (ALA)-induced protoporphyrin-IX fluorescence in rat oesophagus by fluorescence microscopic examination and then studied the effects of PDT. RESULTS: The highest level of fluorescence was achieved in the mucosa after 4 h of 300 mg/kg ALA administration. A clear difference in fluorescence between mucosa and muscularis was found in all samples except those taken 24 h after ALA administration. PDT with ALA caused destruction of the mucosal and, partly, submucosal layers of the oesophagus without damaging the muscularis layer. CONCLUSIONS: According to our results with microscopic fluorescence kinetics and the preliminary results of PDT, selective destruction of the superficial layer of the rat oesophagus is achieved with PDT after ALA administration. 相似文献
106.
Zhenhao Ding Hiromichi Kasahara Michihiko Nakano Junya Suehiro 《IET nanobiotechnology / IET》2017,11(5):562
In this study, an electrical DNA detection method was applied to bacterial detection. DNA was extracted from bacteria and amplified by polymerase chain reaction. The microbeads were labelled with amplicons, altering their surface conductance and therefore their dielectrophoresis characteristics. Amplicon‐labelled microbeads could thus be trapped within a high‐strength electric field, where they formed a pearl chain between the electrodes, resulting in an increased conductance between the electrodes. This method reduces the amplicon detection time from 1–2 h to 15 min, compared with the conventional method. The presented method realised quantitative detection of specific bacteria at concentrations above 1 × 105 and 2.4 × 104 CFU/ml for bacterial solutions with and without other bacterial presence, respectively.Inspec keywords: microorganisms, enzymes, molecular biophysics, biochemistry, electrophoresis, bioelectric phenomena, DNA, biosensors, electrochemical electrodes, electrochemical sensors, microsensors, bioMEMS, surface conductivityOther keywords: bacterial detection, polymerase chain reaction, microbead dielectrophoresis characteristics, electrical DNA detection, surface conductance, amplicon‐labelled microbeads, high‐strength electric field, pearl chain, electrodes, amplicon detection time, quantitative detection, bacterial solutions, time 15 min to 2 h 相似文献
107.
This paper addresses a new type of model predictive control problem for a hybrid system that consists of a continuous‐time linear system and a temporal/spatial directed graph, called a directed‐graph constrained system. Motivated by the obstacle avoidance problem, the problem is newly formulated, where the continuous‐time control input and the waypoints of the state are simultaneously optimized under a temporal/spatial directed graph as well as input/state linear constraints, and a method for efficiently solving this problem is developed. Numerical examples are presented to verify that the proposed approach is effective. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
108.
Hiromichi Kiuchi Kimio Funaki Tokiaki Tanaka 《Metallurgical and Materials Transactions B》1983,14(3):347-352
In this research, the two-step thermochemical cycle shown below is proposed and experimental studies were made on the cycle. $$\frac{\begin{gathered} {\text{Ni}}_{\text{3}} {\text{S}}_{\text{2}} + {\text{H}}_{\text{2}} {\text{S}} = {\text{3NiS + H}}_{\text{2}} \hfill \\ {\text{3NiS = Ni}}_{\text{3}} {\text{S}}_{\text{2}} {\text{ + 0}}{\text{.5S}}_{\text{2}} {\text{(g)}} \hfill \\ \end{gathered} }{{{\text{H}}_{\text{2}} {\text{S = H}}_{\text{2}} {\text{ + 0}}{\text{.5S}}_{\text{2}} {\text{(g)}}}}$$ In the case where Ni3S2 alone was used without inert additions, nickel sulfide sintered or partly fused due to the melting point depression resulting from the thermal decomposition of formed NiS. Such sintering could be prevented by mixing the nickel sulfide powders with Al2O3 or MoS2. The cyclic reactions were thereby shown to provide a stationary high decomposition rate of H2S. Polysulfides, such as MS2, have previously been employed in this kind of cycle. This research showed that the use of lower sulfides such as Ni3S2 may be regarded as rather promising based on the thermodynamic investigation of the respective reactions composing the cycle. The comparison between the sulfurization reactions of NiS to NiS2 and of Ni3S2 to NiS further showed that the latter was superior to the former with respect to the kinetics and thermodynamical properties of the reaction. 相似文献
109.
The rheo-optical properties of a high-density polyethylene having a row-nucleated crystalline texture of a-axis orientation were investigated in the machine direction (MD) and transverse direction (TD) of fabricating the specimen. The tensile complex dynamic compliance function displays two dispersions designated as the α2 and α2 mechanical retardation processes with activation energies of about 21 and 35 kcal mol?1, respectively, for both MD and TD specimens, and the complex dynamic stress-optical coefficient function exhibits a single discrete dispersion designated as the α optical retardation process with an activation energy of about 24 kcal mol?1 for both specimens over the same frequency and temperature ranges as those covered for the dynamic mechanical measurements. The real and imaginary components of converge from positive values to almost zero at the highest frequencies and lowest temperatures covered for both specimens, with the exception of the real component of the MD specimen which converges to a small but definitely negative value. The analysis of this anomalous behaviour of the MD specimen in terms of the optical retardation time spectrum has ascribed the negative convergence to a negative form birefringence that arises from a dynamic lamellar splaying or bending process responding in phase with the dynamic bulk stress. The dynamic X-ray diffraction studies have revealed the α optical dispersion and possibly the α mechanical dispersion to be mostly attributed to the crystal orientation dispersions involving intralamellar shearing processes, i.e. detwisting and tilting processes of the lamellar segments for the MD and TD specimens, respectively. The optical dispersion, if any, associated with the lamellar splaying or bending process may be expected at higher frequencies or lower temperatures than those covered here to assign the β mechanical dispersion to the interlamellar shearing process. 相似文献
110.
Jerry F. Kriz Hiromichi Shimada Yuji Yoshimura Nobuyuki Matsubayashi Akio Nishijima 《Fuel》1995,74(12):1852-1857
A series of nickel-containing catalysts was prepared by a sequence of impregnation and calcining steps using a γ-alumina support. The calcined catalysts were reduced in a flow of hydrogen and mixtures of hydrogen with hydrogen sulfide. Both the calcining temperature and nickel loading strongly influenced the hydrogenation activity. The changes in surface species which resulted from some of the preparation steps were identified by spectroscopy. The catalysts containing nickel without molybdenum were quickly poisoned by sulfur, but a certa in sulfur tolerance was achieved by a two-step impregnation and calcining procedure. Improved hydrogenation activity and high hydrogenation vs. hydrocracking selectivity of nickel—molybdenum catalysts were obtained with relatively low loading of molybdenum and high loading of nickel. A three-step impregnation and calcining procedure appeared to produce the most effective catalysts. 相似文献