Showing papers by "Hiroshima University published in 1992"

Implementation of genetic algorithm for distribution systems loss minimum re-configuration

Abstract: The loss minimum reconfiguration problem in the open loop radial distribution system is basically one of complex combinatorial optimization, since the normal open sectionalizing switches must be determined appropriately. The genetic algorithm was successfully applied to the loss minimum reconfiguration problem. In the proposed algorithm, strings consist of sectionalizing switch status or radial configurations, and the fitness function consists of the total system losses and penalty value of voltage drop and current capacity violations. The loss minimum reconfiguration problem is formulated as a mixed integer programming problem. The essential components of the genetic algorithm are briefly described. A detailed solution methodology by the use of genetic algorithm is outlined. Numerical examples demonstrate the validity and effectiveness of the proposed methodology. >

Searching for a mobile intruder in a polygonal region

Abstract: The problem of searching for a mobile intruder in a simple polygon by a single mobile searcher is considered. This paper investigates the capabilities of searchers having different degrees of visibility by introducing the searcher having k flashlights whose visibility is limited to k rays emanating from his position, and the searcher having a point light source who can see in all directions simultaneously. This paper presents necessary and sufficient conditions for a polygon to be searchable by various searchers. The paper also introduces a class of polygons for which the searcher having two flashlights is as capable as the searcher having a point light source, and it gives a simple necessary and sufficient condition for such polygons to be searchable by the searcher having two flashlights. The complexity of generating a search schedule under some of these conditions is also discussed. Many of the results are proved using chord systems that represent the visibility relations among the vertices and edges o...

Biological nitrogen fixation in mixed legume-cereal cropping systems

Abstract: Cereal/legume intercropping increases dry matter production and grain yield more than their monocultures. When fertilizer N is limited, biological nitrogen fixation (BNF) is the major source of N in legume-cereal mixed cropping systems. The soil N use patterns of component crops depend on the N source and legume species. Nitrogen transfer from legume to cereal increases the cropping system's yield and efficiency of N use. The use of nitrate-tolerant legumes, whose BNF is thought to be little affected by application of combined N, may increase the quantity of N available for the cereal component. The distance between the cereal and legume root systems is important because N is transferred through the intermingling of root systems. Consequently, the most effective planting distance varies with type of legume and cereal. Mutual shading by component crops, especially the taller cereals, reduces BNF and yield of the associated legume. Light interception by the legume can be improved by selecting a suitable plant type and architecture. Planting pattern and population at which maximum yield is achieved also vary among component species and environments. Crops can be mixed in different proportions from additive to replacement or substitution mixtures. At an ideal population ratio a semi-additive mixture may produce higher gross returns.

Effects of First Language on Second Language Writing: Translation versus Direct Composition†

Abstract: This study of English compositions written by 48 Japanese university students examined: (1) differences between the texts resulting from two writing processes, one writing first in Japanese and then translating into English and the other composing directly in English and (2) the relationship between these two writing processes and students’ language proficiency. In terms of quality of content, organization, and style, lower-level writers tended to benefit from translation, whereas higher-level writers did not benefit much. Overall, syntactic complexity was greater in translations than in direct writings. In terms of error frequency, higher-level students tended to make more errors that interfered with intended meaning in translation than in direct writing, but lower-level students did not show any difference. Regarding the correlation between language proficiency and the quality of the writing resulting from the two composing processes, oral skills related more closely to writing quality than did grammar knowledge, particularly for direct writing.

A novel transcriptional regulation mechanism in the flagellar regulon of Salmonella typhimurium: an anti‐sigma factor inhibits the activity of the flagellum‐specific Sigma factor, σF

Abstract: Summary We have studied the molecular mechanism of the negative regulation by flgM of the late operons of the flagellar regulon of Salmonella typhimurium. A 7.8 kDa protein that was identified as the flgM gene product was purified to homogeneity; its amino-terminal sequence was identical to the deduced sequence except for the lack of the initiating methionine. The purified FlgM repressed transcription from the fliC promoter, one that is activated by the sigma factor, FliA (σF). No DNA-binding activity was detected in FlgM. Chemical cross-linking experiments showed that the purified FlgM bound to σF and disturbed Its ability to form a complex with RNA polymerase core enzyme. These results indicate that FlgM is a novel type of negative regulator that probably inactivates the flagellum-specific sigma factor through direct interaction, i.e. it is an anti-sigma factor.

Tissue compatibility and stability of a new zirconia ceramic in vivo.

Abstract: Tissue reaction and stability of partially stabilized zirconia ceramic in vivo was evaluated with the use of the subcutaneous implantation test. During the experimental period, zirconia ceramic was completely encapsulated by a thin fibrous connective tissue with less than 80 microns thickness. No changes of weight and 3-point bending strength were detected after 12 months of implantation. The result suggests that zirconia ceramic is biocompatible and no degradation of zirconia ceramic occurred.

Reaction of sevoflurane and its degradation products with soda lime. Toxicity of the byproducts.

Abstract: Sevoflurane previously has been reported to undergo extensive degradation in the presence of soda lime. To more completely characterize the extent and significnce of this reaction, we studied degradation of sevoflurane with and without soda lime, as well as the toxicity and mutagenicity of the degradation products. Two degradation products detected were CF2 = C(CF3)OCH2F (compound A) and CH3OCF2CH(CF3)OCH2F (compound B). During circulation of 1%, 2%, and 3% sevoflurance in a closed anesthesia circuit for 8 h, peak concentrations of compound A were 13.3 +/- 0.27, 30.2 +/- 0.10, and 42.1 +/- 1.07 ppm at 2 h, respectively. The concentrations of compound B did not exceed 2 ppm. The temperature of the soda lime was 43.3 +/- 2.8 degrees C at 1 h and increased gradually to 47.9 +/- 1.5 degrees C after 8 h. In closed flasks with soda lime, the magnitude of the decrease in sevoflurance concentrations (3%) and of the increase in compound A concentrations was temperature dependent. The peak concentrations of compound A at 23 degrees C, 37 degrees C, and 54 degrees C were 32.8 +/- 6.8 at 2 h, 46.6 +/- 1.0 at 0.5 h, and 78.5 +/- 2.3 ppm at 0.5 h, respectively. The LC50 (50% lethal concentration) of compound A in Wistar rats was 1,090 ppm in males and 1,050 ppm in females exposed for 1 h. The LC50 was 420 ppm in males and 400 ppm in females exposed for 3 h. The chronic toxicity of compound A in Wistar rats was studied by exposing rats 24 times, for 3 h each, to initial concentrations of 30, 60, or 120 ppm in a ventilated chamber. At all concentrations, there were no apparent effects other than a loss of body weight in females (120 ppm) on the final day (P < 0.01). Compound A did not induce mutation on the reverse (Ames) test at less than 2,500 micrograms/dish (culture medium 2.7 ml) with activation by S-9 mixture, and below 1,250 micrograms/dish (culture medium 2.7 ml) without activation, in four strains of S. typhimurium and in 1 strain of E. coli. Exposure of fibroblasts to 7,500 ppm of compound A for 1 h, compound A did not induce structural change. In a study of acute toxicity of compound B, there was no toxicity in Wistar rats after 3 h of exposure at 2,400 ppm. The reverse (Ames) test for compound B was negative at 625-1,250 micrograms/dish.(ABSTRACT TRUNCATED AT 400 WORDS)

Somatic mutation of the APC gene in gastric cancer: frequent mutations in very well differentiated adenocarcinoma and signet-ring cell carcinoma

Abstract: We searched for somatic mutations of the adenomatous polyposis coli (APC) gene in DNA samples isolated from 57 sporadic gastric cancers, by means of a ribonuclease (RNase) protection analysis coupled with DNA amplification by the polymerase chain reaction (PCR). Examining 30% of the APC coding region, including a region where somatic mutations in colorectal tumors are known to be clustered, we detected somatic mutations in 12 tumors; seven in 17 very well differentiated adenocarcinomas, two in 19 well or moderately differentiated adenocarcinomas, and three in ten signet-ring cell carcinomas. So far, no somatic mutations have been identified in 11 poorly differentiated adenocarcinomas. Eight of the 17 somatic mutations found in 12 tumors caused truncation of the gene product due to a nonsense mutation and a 1-, 2- or 5-bp deletion; nine others were point mutations that altered amino acids. Our results suggest that inactivation of APC plays a role in development of some gastric cancers, particularly very well differentiated adenocarcinomas and signet-ring cell carcinomas.

A solution method of unit commitment by artificial neural networks

Abstract: The authors explore the possibility of applying the Hopfield neural network to combinatorial optimization problems in power systems, in particular to unit commitment. A large number of inequality constraints included in unit commitment can be handled by dedicated neural networks. As an exact mapping of the problem onto the neural network is impossible with the state of the art, a two-step solution method was developed. First, generators to be stored up at each period are determined by the network, and then their outputs are adjusted by a conventional algorithm. The proposed neural network could solve a large-scale unit commitment problem with 30 generators over 24 periods, and results obtained were very encouraging. >

Diprotonated Sapphyrin: A Fluoride Selective Halide Anion Receptor

Abstract: Prior solid-state structural evidence (Sessler, J.L.;Cyr,M.J.;Lynch,V.;McGhee, E.;J.A.J.Am.Chem. Soc. 1990, 112, 2810-2813) served to indicate that the diprotonated form of 3;8;12;13;17;22-hexaethyl-2,7,18,23-tetramethylsapphyrin ([2.2H] 2+ , as its mixed fluoride-hexafluorophosphate salt, [1.2H.F].PF 6 , is capable of encapsulating fluoride anion within its ca. 5.5 A diameter pentaaza macrocyclic core. The present report describes solution-phase studies related to these earlier solid-state ones

Imperfect debugging models with fault introduction rate for software reliability assessment

Abstract: In general it is considered to be unrealistic in software reliability modelling to assume that the faults detected by software testing are perfectly removed without introducing new faults. In this paper we propose two software reliability assessment models with imperfect debugging by assuming that new faults are sometimes introduced when the faults originally latent in a software system are corrected and removed during the testing phase. It is assumed that the fault detection rate is proportional to the sum of the numbers of faults remaining originally in the system and faults introduced by imperfect debugging. These two models are described by a nonhomogeneous Poisson process. Several quantitative measures for reliability assessment are derived, and the maximum likelihood estimations of unknown model parameters are presented. Finally, numerical examples of software reliability analysis based on these two models are shown.

Crumbling of dacite dome lava and generation of pyroclastic flows at Unzen volcano

Abstract: RECENT modelling of volcanic eruptions has shown that the efficiency of subsurface degassing of magmas determines whether magma erupts explosively or effuses quietly1,2. Slow uprise of magma is often accompanied by effective degassing, leading to the extrusion of lava flows and domes. Although lava dome extrusion is one of the less explosive modes of eruption, it is often accompanied by explosive pyroclastic activities3–5. The 1991 eruption of Unzen volcano provided an opportunity to observe at close range several types of small-scale pyroclastic flow (glowing avalanches) originating from lava domes. Most of the pyroclastic flows are of Merapi type, caused by blocks falling from a collapsing dome; others are of Pelean type originating in an explosion from the side of a dome. The lavas apparently show variable degrees of self-explosivity. We suggest that variable degrees of degassing of the magma produced a wide range of excess pore pressures in the extruded lava domes, resulting in both Merapi-type and Pelean-type pyroclastic flows from the domes.

Analytic approach to the perturbative expansion of nonlinear gravitational fluctuations in cosmological density and velocity fields.

Abstract: Equations of self-gravitating systems in the Universe are solved by expanding as perturbation series in Fourier space. The formulas for the higher-order terms are given for density and velocity fields. We apply the formulas to several analytically integrable models whose linear density power spectra obey a single power law, and asymptotically approach the prediction of the cold-dark-matter scenario. We explicitly give the nonlinear gravitational evolution for the fields and its dependence on the initial spectrum.

Chromosome Abnormalities in Adult T-Cell Leukemia/Lymphoma: A Karyotype Review Committee Report

Abstract: Karyotypes of 107 cases with adult T-cell leukemia/lymphoma (58 male, 49 female; 81 acute or lymphoma type, 26 chronic or smoldering type) were reviewed by a panel of cytogeneticists and were correlated with the subtypes of the disease. Clonal chromosome abnormalities were found in 103 (96%) cases, of which four had hypotetraploidy. Of 184 numerical abnormalities in the remaining 99 cases with near- or pseudodiploidy, trisomies for chromosomes 3 (21% of cases), 7 (10%), and 21 (9%), monosomy for X chromosome (38%) in the female, and loss of a Y chromosome (17%) in the male were more frequent than expected (P or

Transforming Growth Factor β1 Induces Apoptotic Cell Death in Cultured Human Gastric Carcinoma Cells

Abstract: Transforming growth factor β1 (TGF-β1) is a potent growth inhibitor for many cell types, including tumor cells. We recently have reported the establishment and characterization of two human gastric scirrhous carcinoma cell lines, HSC-39 and HSC-43. Here we examined the effect of TGF-β1 on the growth of these lines as compared to five other human gastric adenocarcinoma cell lines. Proliferation of HSC-39 and HSC-43 cells was strongly inhibited by TGF-β1, whereas the other gastric adenocarcinoma cell lines were unresponsive to TGF-β1. Both HSC-39 and HSC-43 cells gradually lost viability following exposure to TGF-β1. This response was dose dependent up to 4 ng/ml. When TGF-β1 was removed, the cells failed to exhibit regrowth, indicating an irreversible growth-inhibitory effect of this agent, leading to cell death. DNA fragments were observed consisting of multimers of approximately 180 base pairs 24 h after TGF-β1 treatment. The chromatin condensation of each cell line was confirmed by Hoechst 33258 fluorochrome staining. Ultrastructurally, condensed and fragmented nuclei were observed in TGF-β1-treated cells. These features are generally associated with apoptotic processes. Both cell death and DNA fragmentation were partially inhibited by cycloheximide, suggesting the requirement for new protein synthesis. Our results suggest that TGF-β1 induces cell death in human gastric scirrhous carcinoma cells in vitro which is mediated by activation of a signal transduction pathway for apoptosis.

Differential immunohistochemical detection of amphiregulin and cripto in human normal colon and colorectal tumors.

Abstract: Thirty-six primary human colorectal tumors, 43 noninvolved colon samples that were adjacent to either carcinomas of adenomas, 22 adenomas, and nine normal colon specimens were immunohistochemically examined for the presence and localization of two epidermal growth factor-related peptides, amphiregulin (AR) and cripto. Within the primary tumors, 18 (50%) showed moderate levels of AR expression. Approximately 60% of the tubular and tubulovillous adenomas were positive for AR expression, whereas only 15% of the adjacent, noninvolved colon mucosa expressed AR. A greater proportion of well-differentiated tumors (71%) were positive for AR expression than were poorly differentiated tumors (18%). All of the nine normal colon specimens were positive. Consequently, AR expression appeared to be associated with both normal and malignant epithelial cells that were more differentiated. The distribution of cripto expression was different. Seventy-nine % of the colon tumors expressed cripto with a frequency of expression that was approximately equivalent between well-differentiated and poorly differentiated tumors. Approximately 86% of the tubulovillous adenomas, but only 43% of the tubular adenomas, were positive for cripto expression. In contrast, whereas AR was expressed in normal colon specimens, none of these tissues expressed cripto, and only 12% of the noninvolved normal colon samples adjacent to tumors or adenomas were positive for cripto. Cripto expression therefore appeared related to neoplasia. These data suggest that AR and cripto may be functioning as potential autocrine and/or paracrine growth factors in the colon and that the differential expression of cripto may serve as a potential tumor marker for colonic carcinogenesis.

Effects of Sex Hormones on Chemotaxis of Human Peripheral Polymorphonuclear Leukocytes and Monocytes

Abstract: The effects of sex hormones on the in vitro chemotaxis of polymorphonuclear leukocytes (PMNs) and monocytes were investigated using fMLP as the chemoattractant. PMNs, monocytes, and plasma were obtained from heparinized peripheral blood of healthy adults. Chemotaxis of PMNs or monocytes treated with sex hormones were tested using 48-well chemotaxis microchambers. The correlation between sex hormone levels in plasma and the chemotactic ability of PMNs from the same donor was also investigated. The chemotaxis of PMNs was enhanced by progesterone, while it was reduced by estradiol. Random migration of PMNs was also enhanced by progesterone and reduced by estradiol. The effect of estradiol on PMN chemotaxis was inhibited by addition of antiestrogens or progesterone. Testosterone did not have a measurable effect on PMN chemotaxis. A significant positive correlation was found between the concentration of progesterone in plasma of females and PMN chemotactic ability in vitro. For males, there was no significant relationship between plasma levels of sex hormones and PMN chemotactic ability. Estradiol and testosterone levels in plasma did not correlate with PMN chemotactic ability. Sex hormones had no effect on the chemotaxis of monocytes. These results suggest that the altered PMN chemotaxis associated with gingival inflammation may be due to the effects of sex hormones.

Detection of Striped Jack Nervous Necrosis Virus (SJNNV) by Enzyme-Linked Immunosorbent Assay (ELISA)

Abstract: The present paper describes the detection of striped jack nervous necrosis virus (SJNNV), the causative agent of viral nervous necrosis, in eggs, larvae, and brood stocks of hatchery-reared and captured striped jack Pseudocaranx dentex by indirect ELISA. An appropriate condition for the ELISA was determined using purified SJNNV and the detection limit of virus antigens was approximately 5 ng/well. All samples of larvae supposed to be affected with the disease were proved positive for the presence of SJNNV antigens in this ELISA test. The viral antigens were also detected in some samples of fertilized eggs and ovaries of spawners but not in the testis or brain. Thus, it was indicated that spawners were an inoculum source of this viral disease in striped jack.

Embryonal long terminal repeat-binding protein is a murine homolog of FTZ-F1, a member of the steroid receptor superfamily.

Abstract: The embryonal long terminal repeat-binding protein, ELP, is present in undifferentiated mouse embryonal carcinoma cells. It binds to and suppresses transcription of the Moloney leukemia virus long terminal repeat in undifferentiated murine embryonal carcinoma cells. We report here that ELP is a mouse homolog of Drosophila FTZ-F1, which positively regulates transcription of the fushi tarazu gene in blastoderm-stage embryos of the fly. As members of the steroid receptor superfamily, ELP and FTZ-F1 have both DNA binding and putative ligand binding domains which are well conserved between the two. ELP and FTZ-F1 function in cells in the extremely early stage of development. A high degree of conservation between the two transcription factors during the evolution of these species indicates the importance of their functions in early-stage embryogenesis. In addition, the sequence elements they recognize do not contain repeat units, in contrast to other steroid receptors, which usually bind to either palindromic or direct repeat sequences.

Length of telomeric repeats in neuroblastoma: correlation with prognosis and other biological characteristics

Abstract: Telomeres are the physical ends of eukaryotic chromosomes. In view of reports of the reduction of telomeric repeats in human malignant tumors, we measured the lengths of telomeric repeats in 55 primary neuroblastomas. The average lengths of telomeric repeats in these tumors fell in a wide range (from 1.1 kb to more than 23 kb) relative to those in ganglioneuromas and normal peripheral mononuclear cells. The reduction of telomeric repeats was significantly correlated with advanced stages of tumor development, poor prognosis, and increased S-phase fractions in tumor cells. On the other hand, three cases of Stage IV-S tumors showed the reduction of telomeric repeats and low percentage of S-phase fractions. These Stage IV-S patients had a good prognosis with spontaneous regression of metastatic tumors.

Experimental studies on biochemical modulation targeting topoisomerase I and II in human tumor xenografts in nude mice.

Abstract: Topoisomerase (topo) I and II are nuclear enzymes which are novel targets of cancer chemotherapy. A new camptothecin (CPT) analog, 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyl-oxy-CPT (CPT-11), is a topo-I inhibitor with a higher activity and less toxicity than CPT. To investigate topo-I and -II-targeting chemotherapy in an in vivo model, we studied the effect of sequential or co-treatment using CPT-11 and adriamycin (ADR) a topo-II inhibitor, in 6 human tumor xenografts (2 esophageal, 2 gastric and 2 colon tumor lines). In sequential treatment, adriamycin was administered i.v. 24 hr after CPT-11 treatment, and no antagonistic effect of this treatment schedule was observed. ADR cytotoxicity was potentiated significantly by CPT-11 pretreatment in the case of 2 esophageal and 2 gastric tumor lines and 1 colon tumor line. On the other hand, co-treatment abolished the sensitivity to CPT-11 and ADR in all 6 tumor lines. Moreover, CPT-11 did not significantly enhance the cytotoxicity of other agents tested, including mitomycin C (MMC) and cisplatin (CDDP). Flow cytometry and dot-blot analyses showed that CPT-11 pretreatment induced an increase in the S-phase cell population with an increase of topo-II mRNA expression after 24 and 48 hr, respectively, in the esophageal and colon tumor lines. These results suggest that CPT-11 can modulate topo-11 levels to enhance the effect of topo-II inhibitors in some human tumors, and this suggests a new clinical method of topo-I and -II targeting chemotherapy for human solid tumors.