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Item

Helicobacter pylori induces gene expression in human gastric cells identified by mRNA differential display

(1996-11-12)

Wong, L

;

Lue, MY

;

Chang, CA

;

Lin, YL

;

Chan, EC

Changes in gene expression patterns in gastric cells infected with Helicobacter pylori were characterized by means of mRNA differential display. Total RNA preparations were extracted from the H. pylori infected gastric cells and paired non-infected cells, and were probed with candidate clones identified after screening up to 6,000 mRNA species. Among them, four clones, 04G-1, 04G-2, 01G-1, and Cppa-2 show significant expression in the infected cells by Northern blot analysis, and they are 199 bp, 196 bp, 228 bp, and 276 bp in length, respectively. Database search revealed that nucleotide sequences of these clones share very low identity with any known sequence. These results indicate that H. pylori can significantly affect gene expression in gastric cells. Furthermore mRNA differential display can be used in pathogenesis studies to identify new genes in gastric cells in response to insults such as H. pylori. (C) 1996 Academic Press, Inc.

Item

Helicobacter pylori induces gene expression in human gastric cells identified by mRNA differential display

(1996-11-12)

Wong, L

;

Lue, MY

;

Chang, CA

;

Lin, YL

;

Chan, EC

Changes in gene expression patterns in gastric cells infected with Helicobacter pylori were characterized by means of mRNA differential display. Total RNA preparations were extracted from the H. pylori infected gastric cells and paired non-infected cells, and were probed with candidate clones identified after screening up to 6,000 mRNA species. Among them, four clones, 04G-1, 04G-2, 01G-1, and Cppa-2 show significant expression in the infected cells by Northern blot analysis, and they are 199 bp, 196 bp, 228 bp, and 276 bp in length, respectively. Database search revealed that nucleotide sequences of these clones share very low identity with any known sequence. These results indicate that H. pylori can significantly affect gene expression in gastric cells. Furthermore mRNA differential display can be used in pathogenesis studies to identify new genes in gastric cells in response to insults such as H. pylori. (C) 1996 Academic Press, Inc.

Item

Band-diagonal operators

(1996-11-15)

Fong, CK

;

Wu, PY

;

應用數學系

;

Department of Applied Mathematics

We show that there are operators on a five-dimensional Hilbert space which are not tridiagonal, and that there are compact operators and normal operators on separable infinite-dimensional spaces which are not band-diagonal.

Item

Numerical microcanonical ensemble method for calculation on statistical models with large lattice sizes

(1996-11-15)

Wang, JZ

;

Yang, TJ

;

交大名義發表

;

電子物理學系

;

National Chiao Tung University

Based on the microcanonical ensemble theory in statistical mechanics, we devise a method that can be used to enhance the capability of numerical calculation on statistical models with large lattice sizes. In our method, we take the expectation value of the energy, as defined in quantum mechanics, instead of the eigenvalue as the energy of a physical system. We show mathematically that the relevant physical quantities obtained in this way are unchanged in the thermodynamical limit and we apply this method to numerical calculations. In this paper, we present our numerical results with the one-dimensional spinless fermionic model as a first test of our method. The numerical calculations are done to a 4096 lattice size using a computer with a speed of about 40 mflops. Our numerical data agree quite well with the exact values. Also, the fluctuation of data is small, in contrast to that obtained using the quantum Monte Carlo method.

Item

Numerical microcanonical ensemble method for calculation on statistical models with large lattice sizes

(1996-11-15)

Wang, JZ

;

Yang, TJ

;

電子物理學系

;

Department of Electrophysics

Based on the microcanonical ensemble theory in statistical mechanics, we devise a method that can be used to enhance the capability of numerical calculation on statistical models with large lattice sizes. In our method, we take the expectation value of the energy, as defined in quantum mechanics, instead of the eigenvalue as the energy of a physical system. We show mathematically that the relevant physical quantities obtained in this way are unchanged in the thermodynamical limit and we apply this method to numerical calculations. In this paper, we present our numerical results with the one-dimensional spinless fermionic model as a first test of our method. The numerical calculations are done to a 4096 lattice size using a computer with a speed of about 40 mflops. Our numerical data agree quite well with the exact values. Also, the fluctuation of data is small, in contrast to that obtained using the quantum Monte Carlo method.

Item

Structure of high resistivity GaAs film grown by low-temperature metalorganic chemical vapor deposition

(1996-11-18)

Chen, WC

;

Chang, CS

;

Chan, SH

;

光電工程學系

;

Department of Photonics

The structure of a low-temperature GaAs layer grown by low-pressure metalorganic chemical vapor deposition with precursors of triethylgallium and arsine is reported. Dense particles containing Ga clusters are found in a high resistivity GaAs film grown at 420 degrees C, The size and concentration of particles are about 800-1000 nm and 7X10(11) cm(-3), respectively. (C) 1996 American Institute of Physics.