| 11. |
- Amnell, Tobias, et al.
(author)
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Code Synthesis for Timed Automata
- 2002
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Reports (other academic/artistic)abstract
- We present a framework for development of real-time embedded systems based on the recently presented model of timed automata extended with real-time tasks. It has been shown previously that design problems such as reachability and schedulability are decidable for the model of timed automata with tasks. In this paper we describe how to automatically synthesise executable code with predictable timing behaviour, which is guaranteed to meet constraints (timing and other) imposed on the design model. To demonstrate the applicability of the framework, implemented in the Times tool, we present a case-study of a well known production cell, built in LEGO and controlled by a Hitachi H8 based LEGO Mindstorm control brick.
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| 12. |
- Cao, Jun, et al.
(author)
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Helicobacter pylori-antigen-binding fragments expressed on the filamentous M13 phage prevent bacterial growth
- 2000
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In: Biochimica et Biophysica Acta - General Subjects. - 0304-4165 .- 1872-8006. ; 1474:1, s. 107-113
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Journal article (peer-reviewed)abstract
- Colonization of the human stomach by Helicobacter pylori is associated with the development of gastritis, duodenal ulcer, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. H. pylori-antigen-binding single-chain variable fragments (ScFv) were derived from murine hybridomas producing monoclonal antibodies and expressed as a g3p-fusion protein on a filamentous M13 phage. The recombinant ScFv-phage reacted specifically with a 30-kDa monomeric protein of a H. pylori surface antigen preparation and by means of immunofluorescence microscopy the phage was shown to bind to both the spiral and coccoid forms of the bacterium. In vitro, the recombinant phage exhibited a bacteriocidal effect and inhibited specifically the growth of all the six strains of H. pylori tested. When H. pylori was pretreated with the phage 10 min before oral inoculation of mice, the colonization of the mouse stomachs by the bacterium was significantly reduced (P<0.01). The results suggest that genetic engineering may be used to generate therapy-effective phages.
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| 13. |
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| 14. |
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| 15. |
- Sun, Y. H., et al.
(author)
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Theoretical studies on nonlinear optical properties of two newly synthesized compounds : PVPHC and DPVPA
- 2004
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In: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 394:03-jan, s. 176-181
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Journal article (peer-reviewed)abstract
- The nonlinear optical properties of two newly synthesized molecules 9-(4-{2-[4-(2-pyridin-4-yl-vinyl)-phenyl]-vinyl}-phenyl)-9H-carbazole (PVPHC) and diphenyl-(4-{2-[4-(2-pyridin-4-yl-vinyl)-phenyl]-vinyl}-phenyl)-amine (DPVPA) have been studied using hybrid density functional theory at B3LYP level. A few-state model, as well as response theory, have been employed to calculate their two-photon absorption cross-sections. The theoretical results are in good agreement with the experimental measurements available. It is found that the maximal two-photon absorption cross-sections of these compounds can be well described by a three-state model and both compounds have large two-photon absorption cross-section in optical regime. Strong charge-transfer process upon excitation has been revealed, indicating that these two compounds are good candidates as two-photon polymerization initiators.
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| 16. |
- Sun, Y. H., et al.
(author)
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Two-photon absorption properties of multi-branched bis-(styryl)benzene based organic chromophores
- 2004
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In: Journal of Molecular Structure. - : Elsevier BV. - 0166-1280. ; 682:03-jan, s. 185-189
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Journal article (peer-reviewed)abstract
- Two-photon absorption (TPA) cross-sections of a series of multi-branched trans-stilbene charge transfer compounds with benzene as the coupling center have been theoretically investigated using analytical response theory at the random phase approximation level. It shows that the TPA cross-sections of compounds with a quasi-one-dimensional geometrical arrangement can be enhanced through the pure electronic coupling of different branches. The effects of different combination of donor/acceptor substitutions on the TPA cross-sections have also been discussed.
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| 17. |
- Sun, Yi-Qian, 1969-
(author)
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Experimental Helicobacter pylori infection in an animal model
- 2004
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Doctoral thesis (other academic/artistic)abstract
- Background: Helicobacter pylori is a microaerophilic Gram-negative bacterium colonizing the human stomach. The prevalence of this infection is between 20-90% depending on geographic location. Comprehensive studies have shown significant relationships between H. pylori infection and chronic gastritis, peptic ulcer and gastric carcinoma. The mechanisms behind these associations are still unclear in many aspects. The objective of this thesis was to elucidate some pathogenetic aspects of H. pylori infection based on an animal model using Mongolian gerbils.Aims: To determine bacterial profiles in the stomach of gerbils with and without H. pylori infection. To study the long-term morpho-functional development of H. pylori-induced gastritis. To investigate the gastric mucosal barrier function and to explore the effects of dietary antioxidant vitamin supplements on H. pylori-associated chronic gastritis.Methods and results: Mongolian gerbils were inoculated with H. pylori ATCC 43504 or culture broth (controls). The animals were killed at scheduled time points. The gastric microflora was profiled and identified by temporal temperature gradient gel electrophoresis (TTGE), cloning and pyrosequencing of 16S rDNA variable V3 region. TTGE and pyrosequencing revealed the presence of a mixed bacterial flora in the stomach of both H. pylori infected and control animals. In both cases, lactobacilli appeared to prevail. In H. pylori-infected gerbils, serum concentrations of anti-H. pylori IgG and gastrin increased over time. Mucosal epithelial proliferation quantified after immunohistochemical labeling with 5-bromo-2'-deoxy-uridine was increased in the antrum in short-term gastritis, followed by an increase in the corpus in the long-term. Gene expression of pro-inflammatory cytokines was quantitated by real-time RT-PCR. Interleukin-1beta and tumor necrosis factor-alpha expression was increased in H. pylori-infected gerbils. Beta-actin was not a reliable endogenous control for relative quantitative RT-PCR. Histological parameters of gastritis were semiquantitatively assessed and expressed as a "gastritis score". Gastritis scores increased over time and reached a peak 32 weeks after inoculation. With time there was an expansion of gastritis from the antrum to the corpus. Severe inflammation, ulcer development and pseudopyloric metaplasia (glandular atrophy) were characteristic features. Gastric mucosal samples were mounted in Ussing chambers and 51Cr-EDTA (paracellular probe) and horseradish peroxidase (HRP, protein antigen) were used as indicators of gastric mucosal barrier function. Short-term gastritis showed increased mucosal permeability to 51Cr-EDTA in the antrum. Long-standing gastritis was associated with increased 51Cr-EDTA permeation in both the antrum and corpus and an increased HRP flux in the antrum. In the vitamin supplement study, concentrations of 3-nitrotyrosine (nitrosative protein damage) and thiobarbituric acid reactive substances (TBARS) (oxidative lipid damage) in the gastric mucosa were determined with an immunodot blot and a fluorometric method, respectively. Mucosal concentrations of carbonyl carbons on proteins (oxidative protein damage) and 8-hydroxydeoxyguanosine (oxidative DNA damage) were determined by ELISA. Vitamin supplements had no effect on the colonization with H. pylori. Vitamin C as well as vitamin E supplements reduced mucosal 3-nitrotyrosine concentrations to normal levels in the infected animals. Vitamin E supplement induced decreased mucosal protein carbonyls and TBARS in short-term gastritis. In addition, vitamin C supplement caused attenuated mucosal oxidative DNA damage and milder mucosal inflammation in short-term gastritis.Conclusions: Lactobacilli, the prevailing indigenous bacterium in the stomach of gerbils, may have a probiotic impact on the colonization of H. pylori. The long-term morpho-functional development in the stomach of H. pylori-infected Mongolian gerbils resembles that of H. pylori-infected humans. H. pylori-induced gastritis in gerbils is associated with a long-standing gastric mucosal barrier dysfunction, which follows the extension of chronic gastritis from the antrum into the corpus over time. This impaired barrier function may contribute to perpetuation of chronic inflammation and may be involved in H. pylori-associated carcinogenesis. Vitamin C as well as vitamin E supplements lead to some short-term protective effects on H. pylori-induced stritis but these effects seem to subside over time when the infection persists.
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| 18. |
- Sun, Yi-Qian, 1969-, et al.
(author)
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Long-standing gastric mucosal barrier dysfunction in Helicobacter pylori-induced gastritis in Mongolian gerbils
- 2004
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In: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 9:3, s. 217-227
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Journal article (peer-reviewed)abstract
- Background and Aims. Helicobacter pylori infection causes chronic gastritis and leads to peptic ulcer and gastric adenocarcinoma. An impaired gastric mucosal barrier could be involved in these processes. Our aim was to investigate gastric barrier function in H. pylori-induced gastritis.Methods. Stripped gastric mucosal tissues of H. pylori-infected Mongolian gerbils (4 weeks and 70 weeks after inoculation, respectively) and controls were mounted in Ussing chambers. 51Cr-EDTA (paracellular probe) and horseradish peroxidase (HRP, protein antigen) were used to assess mucosal barrier function. The electrophysiological parameters of the mucosa (transepithelial potential, short circuit current, and transepithelial resistance) were monitored as measurements of barrier integrity and viability. Tissue histology was performed to assess inflammation.Results. In the antrum, both short-term gastritis [4.68 (3.88–5.74) × 10−6 vs. control 2.86 (2.34–3.77) × 10−6 cm/s, p < .001] and gastritis of long-standing [5.72 (3.88–10.94) × 10−6 cm/s, p < .001 vs. control] showed increased permeability to 51Cr-EDTA. In long-standing antral gastritis there was also an increased HRP flux [9.01 (2.98–45.02) vs. control 0.52 (0.06–1.20) pmol/h/cm2, p < .001]. In the corpus, permeability to 51Cr-EDTA was increased only in long-standing gastritis [4.63 (3.64–7.45) × 10−6 vs. control 2.86 (2.12–3.98) × 10−6 cm/s, p < .01]. Gastric mucosal permeability to 51Cr-EDTA was correlated to histological inflammation and inflammatory activity. The levels of serum anti-H. pylori immunoglobulin G were positively correlated to HRP flux and 51Cr-EDTA permeation.Conclusions. Helicobacter pylori-induced gastritis in Mongolian gerbils was associated with a long-standing gastric mucosal barrier dysfunction. The barrier defect extended from the antrum into the corpus over time. This impaired barrier function may contribute to perpetuation of chronic inflammation and may be involved in H. pylori-associated carcinogenesis.
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| 19. |
- Sun, Yi-Qian, 1969-, et al.
(author)
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Profiling and identification of eubacteria in the stomach of Mongolian gerbils with and without Helicobacter pylori infection
- 2003
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In: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 8:2, s. 149-157
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Journal article (peer-reviewed)abstract
- Background. Mongolian gerbils are frequently used to study Helicobacter pylori-induced gastritis and its consequences. The presence of an indigenous bacterial flora with suppressive effect on H. pylori may cause difficulties with establishing this experimental model.Aim. The aim of the present study was to determine bacterial profiles in the stomach of Mongolian gerbils with and without (controls) H. pylori infection.Methods. Gastric tissue from H. pylori ATCC 43504 and CCUG 17874 infected and control animals were subjected to microbial culturing and histology. In addition, gastric mucosal samples from H. pylori ATCC 43504 infected and control animals were analyzed for bacterial profiling by temporal temperature gradient gel electrophoresis (TTGE), cloning and pyrosequencing of 16S rDNA variable V3 region derived PCR amplicons.Results. Oral administration of H. pylori ATCC 43504, but not CCUG 17874, induced colonization and gastric inflammation in the stomach of Mongolian gerbils. Temporal temperature gradient gel electrophoresis (TTGE) and partial 16S rDNA pyrosequencing revealed the presence of DNA representing a mixed bacterial flora in the stomach of both H. pylori ATCC 43504 infected and control animals. In both cases, lactobacilli appeared to be dominant.Conclusion. These findings suggest that indigenous bacteria, particularly lactobacilli, may have an impact on the colonization and growth of H. pylori strains in the stomach of Mongolian gerbils.
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| 20. |
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