Search

Your search keyword '"Koike, C"' showing total 321 results
Start Over Author "Koike, C"
321 results on '"Koike, C"'

1. Proscriptive Bayesian Programming Application for Collision Avoidance

Author

Koike, C, Pradalier, C, Bessiere, P, and Mazer, E

Subjects
Computer Science: Robotics, Robotics
Abstract

Evolve safely in an unchanged environment and possibly following an optimal trajectory is one big challenge presented by situated robotics research field. Collision avoidance is a basic security requirement and this paper proposes a solution based on a probabilistic approach called Bayesian Programming. This approach aims to deal with the uncertainty, imprecision and incompleteness of the information handled. Some examples illustrate the process of embodying the programmer preliminary knowledge into a Bayesian program and experimental results of these examples implementation in an electrical vehicle are described and commented. Some videos illustrating these experiments can be found at http://www-laplace.imag.fr.

Published
2003

2. Obstacle Avoidance and Proscriptive Bayesian Programming

Author

Koike, C, Pradalier, C, Bessiere, P, and Mazer, E

Subjects
Computer Science: Robotics, Robotics
Abstract

Unexpected events and not modeled properties of the robot environment are some of the challenges presented by situated robotics research field. Collision avoidance is a basic security requirement and this paper proposes a probabilistic approach called Bayesian Programming, which aims to deal with the uncertainty, imprecision and incompleteness of the information handled to solve the obstacle avoidance problem. Some examples illustrate the process of embodying the programmer preliminary knowledge into a Bayesian program and experimental results of these examples implementation in an electrical vehicle are described and commented. A video illustration of the developed experiments can be found at http://www.inrialpes.fr/sharp/pub/laplace

Published
2003

3. Mid-infrared spectra of the shocked Murchison CM chondrite: Comparison with astronomical observations of dust in debris disks

Author

Morlok, A., Koike, C., Tomioka, N., Mann, I., and Tomoeka, K.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

We present laboratory mid-infrared transmission/absorption spectra obtained from matrix of the hydrated Murchison CM meteorite experimentally shocked at peak pressures of 10 to 49 GPa, and compare them to astronomical observations of circumstellar dust in different stages of the formation of planetary systems. The laboratory spectra of the Murchison samples exhibit characteristic changes in the infrared features. A weakly shocked sample (shocked at 10 GPa) shows almost no changes from the unshocked sample dominated by hydrous silicate (serpentine). Moderately shocked samples (21 to 34 GPa) have typical serpentine features gradually replaced by bands of amorphous material and olivine with increasing shock pressure. A strongly shocked sample (36 GPa) shows major changes due to decomposition of the serpentine and due to devolatilization. A shock melted sample (49 GPa) shows features of olivine recrystallized from melted material. The spectra of highly shocked Murchison samples (36 and 49 GPa) are similar to those of dust in the debris disks of HD113766 and HD69830, and the transitional disk of HD100546. The moderately shocked samples (21 to 34 GPa) exhibit spectra similar to those of dust in the debris disks of Beta Pictoris and BD+20307, and the transitional disk of GM Aur. An average of the spectra of all Murchison samples (0 to 49 GPa) has a similarity to the spectrum of the older protoplanetary disk of SU Auriga. In the gas-rich transitional and protoplanetary disks, the abundances of amorphous silicates and gases have widely been considered to be a primary property. However, our study suggests that impact processing may play a significant role in generating secondary amorphous silicates and gases in those disks. Infrared spectra of the shocked Murchison samples are also suggesting that the comets also contain shocked Murchison-like material.

Published
2022
Full Text
View/download PDF

4. Mid-infrared spectra of differentiated meteorites (achondrites): Comparison with astronomical observations of dust in protoplanetary and debris disks

Author

Morlok, A., Koike, C., Tomeoka, K., Mason, A. B., Lisse, C. M., Anand, M., and Grady, M. M.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Physics - Geophysics
Abstract

Mid-infrared (5 micron to 25 micron) transmission/absorption spectra of differentiated meteorites (achondrites) were measured to permit comparison with astronomical observations of dust in different stages of evolution of young stellar objects. In contrast to primitive chondrites, achondrites underwent heavy metamorphism and/or extensive melting and represent more advanced stages of planetesimal evolution. Spectra were obtained from primitive achondrites (acapulcoite, winonaite, ureilite, and brachinite) and differentiated achondrites (eucrite, diogenite, aubrite, and mesosiderite silicates). The ureilite and brachinite show spectra dominated by olivine features, and the diogenite and aubrite by pyroxene features. The acapulcoite, winonaite, eucrite, and mesosiderite silicates exhibit more complex spectra, reflecting their multi-phase bulk mineralogy. Mixtures of spectra of the primitive achondrites and differentiated achondrites in various proportions show good similarities to the spectra of the few Myr old protoplanetary disks HD104237A and V410 Anon 13. A spectrum of the differentiated mesosiderite silicates is similar to the spectra of the mature debris disks HD172555 and HD165014. A mixture of spectra of the primitive ureilite and brachinite is similar to the spectrum of the debris disk HD113766. The results raise the possibility that materials produced in the early stage of planetesimal differentiation occur in the protoplanetary and debris disks.

Published
2022
Full Text
View/download PDF

5. Comparative Evaluation of Fundus Image Interpretation Accuracy in Glaucoma Screening Among Different Physician Groups

Author

Wada-Koike C, Terauchi R, Fukai K, Sano K, Nishijima E, Komatsu K, Ito K, Kato T, Tatemichi M, Kabata Y, and Nakano T

Subjects
glaucoma, fundus images, sensitivity, specificity, health checkup, Ophthalmology, RE1-994
Abstract

Chiharu Wada-Koike,1,&ast; Ryo Terauchi,1,&ast; Kota Fukai,2 Kei Sano,1 Euido Nishijima,1 Koji Komatsu,1 Kyoko Ito,3 Tomohiro Kato,3 Masayuki Tatemichi,2 Yoshiaki Kabata,4,&ast; Tadashi Nakano1 1Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan; 2Department of Preventive Medicine, Tokai University School of Medicine, Isehara, Japan; 3Centre for Preventive Medicine, The Jikei University School of Medicine, Tokyo, Japan; 4Department of Ophthalmology, Jikei University School of Medicine, Daisan Hospital, Tokyo, Japan&ast;These authors contributed equally to this workCorrespondence: Yoshiaki Kabata, Department of Ophthalmology, Jikei University School of Medicine, Daisan Hospital, 4-11-1 Izumihontyou, Komae-si, Tokyo, 125-8506, Japan, Tel +81 3 3480 1151, Fax +81 3 3480 5700, Email kabata22122@gmail.comPurpose: To examine the variability in glaucoma screening using fundus images among physicians, including non-ophthalmologists.Patients and Methods: Sixty-nine eyes from 69 patients, including 25 eyes with glaucoma, were included from the Jikei University Hospital from July 2019 to December 2022. Fundus images were captured using TRC-NW8 (Topcon Corporation, Tokyo, Japan), and were interpreted by 10 non-ophthalmologists, 10 non-specialist ophthalmologists, and 9 specialists for diagnostic accuracy. We analyzed differences in diagnostic accuracy among the three groups. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Kappa coefficient were compared, using the Kruskal–Wallis test followed by a post hoc Dunn’s test.Results: The sensitivity and specificity were 0.22 and 0.92 for non-ophthalmologists, 0.49 and 0.83 for non-specialist ophthalmologists, and 0.68 and 0.87 for specialists, respectively. Both specialists and non-specialist ophthalmologists showed significantly higher sensitivity than non-ophthalmologists (Dunn’s test, P< 0.001 and P=0.031). There was no significant difference in specificity among the three groups (Kruskal–Wallis test, P=0.086). The PPV did not differ significantly between the groups (Kruskal–Wallis test, P=0.108), while the NPV was significantly higher in specialists compared to non-ophthalmologists (Dunn’s test, P< 0.001). Specialists also had a significantly higher Kappa coefficient than non-ophthalmologists and non-specialist ophthalmologists (Dunn’s test, P< 0.001 and P=0.024).Conclusion: Diagnostic accuracy varied significantly based on the physician’s background.Keywords: glaucoma, fundus images, sensitivity, specificity, health checkup

Published
2024

7. Morphological effects on IR band profiles: Experimental spectroscopic analysis with application to observed spectra of oxygen-rich AGB stars

Author

Tamanai, A., Mutschke, H., Blum, J., Posch, Th., Koike, C., and Ferguson, J. W.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

To trace the source of the unique 13, 19.5, and 28 $\mu$m emission features in the spectra of oxygen-rich circumstellar shells around AGB stars, we have compared dust extinction spectra obtained by aerosol measurements. We have measured the extinction spectra for 19 oxide powder samples of eight different types, such as Ti-compounds (TiO, TiO$_2$, Ti$_2$O$_3$, Ti$_3$O$_5$, Al$_2$TiO$_5$, CaTiO$_3$), $\alpha$-, $\gamma$-, $\chi$-$\delta$-$\kappa$-Al$_2$O$_3$, and MgAl$_2$O$_4$ in the infrared region (10 - 50 $\mu$m) paying special attention to the morphological (size, shape, and agglomeration) effects and the differences in crystal structure. Anatase (TiO$_2$) particles with rounded edges are the possible 13, 19.5 and 28 $\mu$m band carriers as the main contributor in the spectra of AGB stars, and spherically shaped nano-sized spinel and Al$_2$TiO$_5$ dust grains are possibly associated with the anatase, enhancing the prominence of the 13 $\mu$m feature and providing additional features at 28 $\mu$m. The extinction data sets obtained by the aerosol and CsI pellet measurements have been made available for public use at http://elbe.astro.uni-jena.de, Comment: 17 pages, 8 figures, Accepted 24 March 2009 for publication in A&A

Published
2009
Full Text
View/download PDF

8. Photo-Luminescence and Possible Forsterite nanoparticles Model of Extended Red Emission

Author

Koike, K., Chihara, H., Koike, C., Nakagawa, M., Okada, M., Matsumura, M., and Takada, J.

Subjects
Astrophysics
Abstract

Possible forsterite nanoparticle model of the Extended Red Emission(ERE) is proposed on the basis of photo-luminescence of forsterite after gamma-ray and neutron irradiation. Forsterite exhibits interesting thermoluminescence spectrum similar to ERE of Red Rectangle after irradiation in low temperature. It is shown that the forsterite after thermoluminescence is over exhibits photo-luminescence(PL) when Ultraviolet ray is irradiated. The structure of PL spectrum is almost similar to that of thermoluminescence. In order to explain small variations of the peak position of wavelength of ERE spectrum, possible nanoparticle model of forsterite is investigated. Our model is consistent to the ISO observation data in near and middle infrared region, which suggest the existence of forsterite., Comment: 5 pages

Published
2004

9. PAHs and crystalline silicates in the post-AGB star IRAS 16279-4757

Author

Matsuura, M., Zijlstra, A. A., Molster, F. J., Hony, S., Waters, L. B. F. M., Kemper, F., Bowey, J. E., Chihara, H., Koike, C., and Keller, L. P.

Subjects
Astrophysics
Abstract

IRAS 16279-4757 belongs to a group of post-AGB stars showing both PAH bands and crystalline silicates. We present mid-infrared images, that resolve the object for the first time. The morphology is similar to that of the `Red Rectangle' (HD 44179), the prototype object with PAHs and crystalline silicates. A two-component model and images suggest a dense oxygen-rich torus, an inner, low-density carbon-rich region and a carbon-rich bipolar outflow. The PAH bands are enhanced at the outflow, while the continuum emission is concentrated towards the center. Our findings support the suggestion that mixed chemistry and morphology are closely related. We discuss the ISO/SWS spectra of IRAS 16279-4757. Several bands in the ISO/SWS spectrum show a match with anorthite: this would be the first detection of this mineral outside the solar system. Compared to HD 44179, the shapes of PAH bands are closer to those of planetary nebulae, possibly related to a population of small PAHs present HD 44179, but absent around IRAS 16279-4757. Detailed examination of the spectra shows the individual character of these two objects. The comparison suggests that the torus found in IRAS 16279-4757 may have formed more recently than that in HD 44179., Comment: accepted to ApJ

Published
2004
Full Text
View/download PDF

10. Thermoluminescence of Simulated Interstellar Matter after Gamma-ray Irradiation

Author

Koike, K., Nakagawa, M., Koike, C., Okada, M., and Chihara, H.

Subjects
Astrophysics
Abstract

Interstellar matter is known to be strongly irradiated by radiation and several types of cosmic ray particles. Simulated interstellar matter, such as forsterite $\rm Mg_{2}SiO_{4}$, enstatite $\rm MgSiO_{3}$ and magnesite $\rm MgCO_{3}$ has been irradiated with the $\rm ^{60}Co$ gamma-rays in liquid nitrogen, and also irradiated with fast neutrons at 10 K and 70 K by making use of the low-temperature irradiation facility of Kyoto University Reactor (KUR-LTL. Maximum fast neutron dose is $10^{17}n_f{\rm /cm^{2}}$). After irradiation, samples are stored in liquid nitrogen for several months to allow the decay of induced radioactivity. We measured the luminescence spectra of the gamma ray irradiated samples during warming to 370K using a spectrophotometer. For the forsterite and magnesite, the spectra exhibit a rather intense peak at about 645 -- 655 nm and 660 nm respectively, whereas luminescence scarcely appeared in olivine sample. The spectra of forsterite is very similar to the ERE of the Red Rectangle., Comment: 7 pages, 9 figures

Published
2002

11. Crystalline silicate dust around evolved stars III. A correlations study of crystalline silicate features

Author

Molster, F. J., Waters, L. B. F. M., Tielens, A. G. G. M., Koike, C., and Chihara, H.

Subjects
Astrophysics
Abstract

We have carried out a quantitative trend analysis of the crystalline silicates observed in the ISO spectra of a sample of 14 stars with different evolutionary backgrounds. We have modeled the spectra using a simple dust radiative transfer model and have correlated the results with other known parameters. We confirm the abundance difference of the crystalline silicates in disk and in outflow sources, as found by Molster et al. (1999, Nature 401, 563). We found some indication that the enstatite over forsterite abundance ratio differs, it is slightly higher in the outflow sources with respect to the disk sources. It is clear that more data is required to fully test this hypothesis. We show that the 69.0 micron feature, attributed to forsterite, may be a very suitable temperature indicator. We found that the enstatite is more abundant than forsterite in almost all sources. The temperature of the enstatite grains is about equal to that of the forsterite grains in the disk sources but slightly lower in the outflow sources. Crystalline silicates are on average colder than amorphous silicates. This may be due to the difference in Fe content of both materials. Finally we find an indication that the ratio of ortho to clino enstatite, which is about 1:1 in disk sources, shifts towards ortho enstatite in the high luminosity (outflow) sources., Comment: 16 pages, 20 figures, accepted by A&A, this paper and others (in this series) can also be found at http://zon.wins.uva.nl/~frankm/papers.html

Published
2002
Full Text
View/download PDF

12. Mechanochemical Synthesis of Amorphous Silicates with an Enstatite and Forsterite Composition.

Author

Koike, C. and Chihara, H.

Subjects
*ENSTATITE, *FORSTERITE, *MECHANICAL alloying, *SILICA, *SILICATES, *ALUMINUM silicates
Abstract

The presence of amorphous silicate particles in interstellar and circumstellar space has been suggested based on the observation of 9.7 and 18 μ m emission bands. We have successfully synthesized amorphous silicate samples of an enstatite and forsterite composition by the mechanical milling of mixed powder consisting of SiO2–MgO and SiO2–Mg(OH)2 reagent-grade particles under different rotation frequencies and milling times. These two types of starting materials are prepared to study the effect of the OH bond on synthesis and crystallization. The amorphous samples were characterized by X-ray diffraction and infrared spectroscopy. Amorphous samples with enstatite composition are synthesized from both SiO2–MgO and SiO2–Mg(OH)2 at 300 rpm and for 300 hr. Amorphous samples with forsterite composition are synthesized from both SiO2–MgO and SiO2–Mg(OH)2. The samples from SiO2–Mg(OH)2 require 400 rpm and a long milling time of 1600 hr. After crystallization, amorphous samples with an enstatite composition synthesized from SiO2–Mg(OH)2 mainly transform into forsterite with small amounts of amorphous silica SiO2 and enstatite depending on the rotation frequencies and milling time, while those from SiO2–MgO become enstatite. The amorphous samples with a forsterite composition are crystallized to forsterite from both starting materials. The presence of H2O or OH bonds significantly affects the final products after the crystallization of amorphous silicates of enstatite composition. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

13. Application of 2-octyl-cyanoacrylate for corneal perforation and glaucoma filtering bleb leak

Author

Okabe M, Kitagawa K, Yoshida T, Koike C, Katsumoto T, Fujihara E, and Nikaido T

Subjects
Ophthalmology, RE1-994
Abstract

Motonori Okabe,1 Kiyotaka Kitagawa,2 Toshiko Yoshida,1 Chika Koike,1 Takeshi Katsumoto,2 Etsuko Fujihara,2 Toshio Nikaido1 1Department of Regenerative Medicine, University of Toyama, Graduate School of Medicine and Pharmaceutical Sciences, Toyama, 2Division of Ophthalmology, Matsue Red Cross Hospital, Japanese Red Cross Society, Shimane, Japan Background: This paper reports on the efficacy of a tissue adhesive, 2-octyl-cyanoacrylate, in the treatment of corneal perforation and glaucoma filtering bleb leak. Methods: Two eyes from two patients with corneal perforation or laceration and two eyes from two patients with bleb leak were included. The patients underwent application of 2-octyl-cyanoacrylate onto the perforated or leaking site, and a hydrogel contact lens was applied as a bandage. We also evaluated the in vitro cell toxicity of 2-octyl-cyanoacrylate in HeLa cells. Results: The two cases of corneal perforation were repaired within 22 days with one application of the tissue adhesive. The two cases of bleb leak were repaired with 2–4 applications of the tissue adhesive over 134 (range 17–134) days). There were no recurrences or adverse effects during a mean follow-up period of 12.7 months. In vitro testing revealed that 2-octyl-cyanoacrylate was markedly toxic to HeLa cells. Conclusion: Four patients with corneal perforation or bleb leak were successfully managed using 2-octyl-cyanoacrylate tissue adhesive. This simple and easy surgical technique may become an alternative therapeutic option for corneal perforation or bleb leak, although several applications of this tissue adhesive may be required. Although 2-octyl-cyanoacrylate was toxic to HeLa cells, no adverse clinical effects were noted using this adhesive. Keywords: corneal perforation, bleb leak, tissue adhesive, 2-octyl-cyanoacrylate

Published
2013

15. Mid-infrared spectra of the shocked Murchison CM chondrite: Comparison with astronomical observations of dust in debris disks

Author

Morlok, A., Koike, C., Tomioka, N., Mann, I., and Tomeoka, K.

Subjects
Silicates -- Analysis, Astronomy -- Analysis, Astronomy -- Spectra, Infrared spectroscopy -- Analysis, Universities and colleges -- Analysis, Meteorites -- Analysis, Meteorites -- Spectra, Astronomy, Earth sciences
Abstract

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2009.11.018 Byline: A. Morlok (a)(b), C. Koike (c), N. Tomioka (a), I. Mann (a), K. Tomeoka (a) Keywords: Infrared observations; Comets, Dust; Debris disks; Meteorites Abstract: We present laboratory mid-infrared transmission/absorption spectra obtained from matrix of the hydrated Murchison CM meteorite experimentally shocked at peak pressures of 10-49GPa, and compare them to astronomical observations of circumstellar dust in different stages of the formation of planetary systems. The laboratory spectra of the Murchison samples exhibit characteristic changes in the infrared features. A weakly shocked sample (shocked at 10GPa) shows almost no changes from the unshocked sample dominated by hydrous silicate (serpentine). Moderately shocked samples (21-34GPa) have typical serpentine features gradually replaced by bands of amorphous material and olivine with increasing shock pressure. A strongly shocked sample (36GPa) shows major changes due to decomposition of the serpentine and due to devolatilization. A shock melted sample (49GPa) shows features of olivine recrystallized from melted material. The infrared spectra of the shocked Murchison samples show similarities to astronomical spectra of dust in various young stellar objects and debris disks. The spectra of highly shocked Murchison samples (36 and 49GPa) are similar to those of dust in the debris disks of HD113766 and HD69830, and the transitional disk of HD100546. The moderately shocked samples (21-34GPa) exhibit spectra similar to those of dust in the debris disks of Beta Pictoris and BD+20307, and the transitional disk of GM Aur. An average of the spectra of all Murchison samples (0-49GPa) has a similarity to the spectrum of the older protoplanetary disk of SU Auriga. In the gas-rich transitional and protoplanetary disks, the abundances of amorphous silicates and gases have widely been considered to be a primary property. However, our study suggests that impact processing may play a significant role in generating secondary amorphous silicates and gases in those disks. Infrared spectra of the shocked Murchison samples also show similarities to the dust from comets (C/2002 V1, C/2001 RX14, 9P/Tempel 1, and Hale Bopp), suggesting that the comets also contain shocked Murchison-like material. Author Affiliation: (a) Department of Earth and Planetary Sciences, Faculty of Science, Kobe University, Nada, Kobe 657-8501, Japan (b) CRPG/CNRS, 54501 Vandoeuvre les Nancy, France (c) Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan Article History: Received 20 April 2009; Revised 21 October 2009; Accepted 10 November 2009

Published
2010

16. Laboratory production of monophase pyrrhotite grains using solid-solid reaction and their characteristic infrared spectra

Author

Kimura, Y., Tamura, K., Koike, C., Chihara, H., and Kaito, C.

Subjects
Astronomy, Earth sciences
Abstract

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2005.03.003 Byline: Y. Kimura (a), K. Tamura (a), C. Koike (b), H. Chihara (b)(c), C. Kaito (a) Keywords: Infrared observations; Interplanetary dust; Solar nebula Abstract: A new method of producing pyrrhotite grains, which are most commonly found in cometary material and interplanetary dust particles, was developed. Pyrrhotite grains in the monophase having a 7C structure were predominately produced using a solid-solid reaction between iron and sulfur grains at room temperature. The characteristic infrared peaks were observed at 602, 563, and 397 cm.sup.-1 (16.6, 17.8, and 25.2 [mu]m). Author Affiliation: (a) Department of Physics, Ritsumeikan University, Noji-higashi 1-1-1, Kusatsu-shi, Shiga 525-8577, Japan (b) Laboratory of Physics, Kyoto Pharmaceutical University, Misasagi, Yamashina, Kyoto 607-8414, Japan (c) Department of Earth and Space Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka 560-0043, Japan Article History: Received 20 April 2004; Revised 24 February 2005

Published
2005

21. TRPM1 mutations are associated with the complete form of congenital stationary night blindness

Author

Makoto Nakamura, Sanuki, R., Yasuma, T. R., Onishi, A., Nishiguchi, K. M., Koike, C., Kadowaki, M., Kondo, M., Miyake, Y., and Furukawa, T.

Subjects
Adult, Male, Heterozygote, genetic structures, DNA Mutational Analysis, Molecular Sequence Data, Intracellular Space, Mutation, Missense, TRPM Cation Channels, Cell Line, Mice, Young Adult, Night Blindness, Electroretinography, Animals, Humans, Genetic Predisposition to Disease, Child, Mice, Knockout, Base Sequence, Pedigree, Protein Transport, Mutation, Female, sense organs, Research Article
Abstract

Purpose To identify human transient receptor potential cation channel, subfamily M, member 1 (TRPM1) gene mutations in patients with congenital stationary night blindness (CSNB). Methods We analyzed four different Japanese patients with complete CSNB in whom previous molecular examination revealed no mutation in either nyctalopin (NYX) or glutamate receptor, metabotropic 6 (GRM6). The ophthalmologic examination included best-corrected visual acuity, refraction, biomicroscopy, ophthalmoscopy, fundus photography, Goldmann kinetic perimetry, color vision tests, and electroretinography (ERG). Exons 2 through 27 and the exon-intron junction regions of human TRPM1 were sequenced. Results Five different mutations in human TRPM1 were identified. Mutations were present in three unrelated patients with complete CSNB. All three patients were compound heterozygotes. Fundus examination revealed no abnormalities other than myopic changes, and the single bright-flash, mixed rod-cone ERG showed a “negative-type” configuration with a reduced normal a-wave and a significantly reduced b-wave amplitude. Our biochemical and cell biologic analyses suggest that the two identified IVS mutations lead to abnormal TRPM1 protein production, and imply that the two identified missense mutations lead to the mislocalization of the TRPM1 protein in bipolar cells (BCs). Conclusions Human TRPM1 mutations are associated with the complete form of CSNB in Japanese patients, suggesting that TRPM1 plays an essential role in mediating the photoresponse in ON BCs in humans as well as in mice.

Published
2010

24. The Production of Heparin Cofactor li Is Not Regulated by Inflammatory Cytokines in Human Hepatoma Cells: Comparison with Plasminogen Activator Inhibitor Type-1

Author

Kenji Niiya, Hideo Sasaki, Koike C, Yumiko Hayakawa, and Nobuo Sakuragawa

Subjects
Heparin cofactor II, medicine.medical_specialty, medicine.medical_treatment, Hematology, Biology, Molecular biology, Proinflammatory cytokine, Hep G2, chemistry.chemical_compound, Endocrinology, Cytokine, Antigen, chemistry, Internal medicine, Plasminogen activator inhibitor-1, medicine, Northern blot, Plasminogen activator
Abstract

SummaryUsing the Northern blot technique, we screened 6 human hepatoma cell lines to investigate the regulation mechanism of heparin cofactor II (HCII) biosynthesis. We found that HuH-7 and Hep G2 cells constitutively expressed the HC II gene. In conditioned medium, HuH-7 cells constantly produced HC II that was functionally active and formed a complex with thrombin in the presence of dermatan sulfate. HC II is thought be an acute phase reactant, and, therefore, we examined the effects of the major inflammatory cytokines, IL-6, IL-1β, and TNF-α, on the regulation of HC II production in HuH-7 and Hep G2 cells. In HuH-7 cells, the antigen and mRNA levels of plasminogen activator inhibitor type-1 (PAI-1), an acute phase protein produced by hepa-tocytes, were increased in response to stimulation with either IL-6 or IL-1 (3 or both, but HC II antigen and mRNA levels were not changed by the same stimulation. Even when Hep G2 cells were treated with a combination of three cytokines, IL-6, IL-1β, and TNF-α, HC II antigen and mRNA levels were not changed; however, PAI-1 antigen and mRNA levels were clearly increased. These results suggest that the production of HC II in hepatoma cells is not regulated by the major inflammatory mediators, IL-6, IL-iβ, and TNF-α.

Published
1996
Full Text
View/download PDF

25. The infrared spectrum of ortho-enstatite from reflectance experiments and first-principle simulations

Author

Demichelis, R., Suto, H., Noël, Y., Sogawa, H., Naoi, T., Koike, C., Chihara, H., Shimobayashi, N., Ferrabone, Matteo, Dovesi, Roberto, Department of Chemistry, Curtin University [Perth], Planning and Transport Research Centre (PATREC)-Planning and Transport Research Centre (PATREC), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Chimica IFM e NIS-Centre of excellence, Università degli studi di Torino (UNITO), and Università degli studi di Torino = University of Turin (UNITO)

Subjects
ComputingMilieux_MISCELLANEOUS, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

International audience

Published
2012
Full Text
View/download PDF

27. The infrared spectrum of ortho-enstatite from reflectance experiments and first-principle simulations

Author

Demichelis, Raffaella, Suto, H., Noel, Y., Sogawa, H., Naoi, T., Koike, C., Chihara, H., Shimobayashi, N., Ferrabone, M., Dovesi, R., Demichelis, Raffaella, Suto, H., Noel, Y., Sogawa, H., Naoi, T., Koike, C., Chihara, H., Shimobayashi, N., Ferrabone, M., and Dovesi, R.

Abstract

Infrared (IR) spectra provide a rich amount of information concerning chemical composition, lattice structure, size and shape of circumstellar dust. Accurate reference data are then required for the analysis of the various detected components. This study provides the IR characterization of one of the most frequently observed compounds, MgSiO3 ortho-enstatite, and shows that IR experiments and ab initio techniques can be used synergically to obtain high-quality data concerning crystalline materials. The IR reflectance spectrum of synthetic ortho-enstatite was collected and compared to ab initio results (Gaussian-type basis set, PBE0 hybrid density functional theory (DFT) functional). An excellent agreement is observed both for vibrational frequencies (ν) and intensities, the latter estimated through the oscillator strength. The mean absolute difference between experimental and calculated ν is of the order of 7–8 cm−1 (43 out of 65 peaks differ by less than 10 cm−1, only four peaks differ by 15–19 cm−1). The static dielectric tensor and its components (electronic and ionic contributions) were measured and compared to calculated data: differences are in the 2–5 per cent range.

Published
2012

29. Functionally important glycosyltransferase gain and loss during catarrhine primate emergence

Author

Koike, C, Uddin, M, Wildman, DE, Gray, EA, Trucco, M, Starzl, TE, Goodman, M, Koike, C, Uddin, M, Wildman, DE, Gray, EA, Trucco, M, Starzl, TE, and Goodman, M

Abstract

A glycosyltransferase, α1,3galactosyltransferase, catalyzes the terminal step in biosynthesis of Galα1,3Galβ1-4GlcNAc-R (αGal), an oligosaccharide cell surface epitope. This epitope or antigenically similar epitopes are widely distributed among the different forms of life. Although abundant in most mammals, αGal is not normally found in catarrhine primates (Old World monkeys and apes, including humans), all of which produce anti-αGal antibodies from infancy onward. Natural selection favoring enhanced resistance to αGal-positive pathogens has been the primary reason offered to account for the loss of αGal in catarrhines. Here, we question the primacy of this immune defense hypothesis with results that elucidate the evolutionary history of GGTA1 gene and pseudogene loci. One such locus, GGTA1P. a processed (intronless) pseudogene (PPG), is present in platyrrhines, i.e.. New World monkeys, and catarrhines but not in prosimians. PPG arose in an early ancestor of anthropoids (catarrhines and platyrrhines), and GGTA1 itself became an unprocessed pseudogene in the late catarrhine stem lineage. Strong purifying selection, denoted by low nonsynonymous substitutions per nonsynonymous site/synonymous substitutions per synonymous site values, preserved CCTA1 in noncatarrhine mammals, indicating that the functional gene product is subjected to considerable physiological constraint. Thus, we propose that a pattern of alternative and/or more beneficial glycosyltransferase activity had to first evolve in the stem catarrhines before GGTA1 inactivation could occur. Enhanced defense against αGal-positive pathogens could then have accelerated the replacement of αGal-positive catarrhines by αGal-negative catarrhines. However, we emphasize that positively selected regulatory changes in sugar chain metabolism might well have contributed in a major way to catarrhine origins. © 2006 by The National Academy of Sciences of the USA.

Published
2007

30. Infrared reflection spectra of forsterite crystal

Author

Sogawa, H., Koike, C., Chihara, H., Suto, H., Tachibana, S., Tsuchiyama, A., 1000090263368, Kozasa, T., Sogawa, H., Koike, C., Chihara, H., Suto, H., Tachibana, S., Tsuchiyama, A., 1000090263368, and Kozasa, T.

Abstract

Polarized infrared reflectance of large single crystals of forsterite was measured for each crystal axis at frequencies between 5000 cm^[−1] and 100 cm^[−1] with a resolution of 1 cm^[−1]. The reflectance spectra were analyzed based on classical dispersion theory. A set of oscillator parameters for crystalline axes of forsterite was obtained. Those parameters are used to derive optical constants of forsterite, which are important for analyses of observed spectra of astronomical objects and laboratory spectra of particle samples. Calculations of absorption for small particles using the bulk optical constants are compared with mid-infrared and far-infrared absorption spectra measured in the laboratory.

Published
2006

32. Polycyclic aromatic hydrocarbons and crystalline silicates in the bipolar post-asymptotic giant branch star IRAS 16279-4757

Author

UCL, Matsuura, M., Zijlstra, AA, Molster, FJ, Hony, S., Waters, LBFM, Kemper, F., Bowey, JE, Chihara, H, Koike, C, Keller, LP, UCL, Matsuura, M., Zijlstra, AA, Molster, FJ, Hony, S., Waters, LBFM, Kemper, F., Bowey, JE, Chihara, H, Koike, C, and Keller, LP

Abstract

IRAS 16279-4757 belongs to a group of post-asymptotic giant branch (post-AGB) stars showing both polycyclic aromatic hydrocarbon (PAH) bands and crystalline silicates. We present mid-infrared images that resolve the object for the first time. The morphology is similar to that of the "Red Rectangle" (HD 44179), the prototype object with PAHs and crystalline silicates. A two-component model and images suggest a dense oxygen-rich torus, an inner, low-density, carbon-rich region, and a carbon-rich bipolar outflow. The PAH bands are enhanced at the outflow, while the continuum emission is concentrated toward the center. Our findings support the suggestion that mixed chemistry and morphology are closely related. We discuss the Infrared Space Observatory Short-Wavelength Spectrometer (ISO SWS) spectra of IRAS 16279-4757. Several bands in the ISO SWS spectrum show a match with anorthite: this would be the first detection of this mineral outside the solar system. Compared to HD 44179, the shapes of PAH bands are closer to those of planetary nebulae, possibly related to a population of small PAHs present in HD 44179 but absent around IRAS 16279-4757. Detailed examination of the spectra shows the individual character of these two objects. The comparison suggests that the torus found in IRAS 16279-4757 may have formed more recently than that in HD 44179.

Published
2004

34. Production of α1,3-galactosyltransferase-deficient pigs

Author

Phelps, CJ, Koike, C, Vaught, TD, Boone, J, Wells, KD, Chen, SH, Ball, S, Specht, SM, Polejaeva, IA, Monahan, JA, Jobst, PM, Sharma, SB, Lamborn, AE, Garst, AS, Moore, M, Demetris, AJ, Rudert, WA, Bottino, R, Bertera, S, Trucco, M, Starzl, TE, Dai, Y, Ayares, DL, Phelps, CJ, Koike, C, Vaught, TD, Boone, J, Wells, KD, Chen, SH, Ball, S, Specht, SM, Polejaeva, IA, Monahan, JA, Jobst, PM, Sharma, SB, Lamborn, AE, Garst, AS, Moore, M, Demetris, AJ, Rudert, WA, Bottino, R, Bertera, S, Trucco, M, Starzl, TE, Dai, Y, and Ayares, DL

Abstract

The enzyme α1,3-galactosyltransferase (α1,3GT or GGTA1) synthesizes α1,3galactose (α1,3Gal) epitopes (Galα1,3Galβ1,4GlcNAc-R), which are the major xenoantigens causing hyperacute rejection in pig-to-human xenotransplantation. Complete removal of α1,3Gal from pig organs is the critical step toward the success of xenotransplantation. We reported earlier the targeted disruption of one allele of the α1,3GT gene in cloned pigs. A selection procedure based on a bacteria[toxin was used to select for cells in which the second allele of the gene was knocked out. Sequencing analysis demonstrated that knockout of the second allele of the α1,3GT gene was caused by a T-to-G single point mutation at the second base of exon 9, which resulted in inactivation of the α1,3GT protein. Four healthy α1,3GT double-knockout female piglets were produced by three consecutive rounds of cloning. The piglets carrying a point mutation in the α1,3GT gene hold significant value, as they would allow production of α1,3Gal-deficient pigs free of antibiotic-resistance genes and thus have the potential to make a safer product for human use.

Published
2003

36. Molecular basis of evolutionary loss of the α1,3-galactosyltransferase gene in higher primates

Author

Koike, C, Fung, JJ, Geller, DA, Kannagi, R, Libert, T, Luppi, P, Nakashima, I, Profozich, J, Rudert, W, Sharma, SB, Starzl, TE, Trucco, M, Koike, C, Fung, JJ, Geller, DA, Kannagi, R, Libert, T, Luppi, P, Nakashima, I, Profozich, J, Rudert, W, Sharma, SB, Starzl, TE, and Trucco, M

Abstract

Galactose-α1,3-galactose (αGal) epitopes, the synthesis of which requires the enzyme product of α1,3-galactosyltransferase (α1,3GT), are sugar chains on the cell surface of most mammalian species. Notable exceptions are higher primates including Old World monkeys, apes, and humans. The αGal-negative species as well as mice with deletion of the α1,3GT gene produce abundant anti-αGal antibodies. The evolutionary loss of αGal epitopes has been attributed to point mutations in the coding region of the gene. Because no transcripts could be found in the higher primate species with Northern blot analysis, a potential alternative explanation has been loss of upstream regulation of the gene. Here, we have demonstrated that the rhesus promoter is functional. More importantly, a variety of full-length transcripts were detected with sensitive PCR-based methods in the tissues of rhesus monkeys, orangutans, and humans. Five crucial mutations were delineated in the coding region of the human and rhesus and three in the orangutan, any one of which could be responsible for inactivation of the α1,3GT gene. Two of the mutations were shared by all three higher primates. These findings, which elucidate the molecular basis for the evolutionary loss of αGal expression, may have implications in medical research.

Published
2002

44. Isolation of the regulatory regions and genomic organization of the porcine α1,3-galactosyltransferase gene1

Author

Koike, C, Friday, RP, Nakashima, I, Luppi, P, Fung, JJ, Rao, AS, Starzl, TE, Trucco, M, Koike, C, Friday, RP, Nakashima, I, Luppi, P, Fung, JJ, Rao, AS, Starzl, TE, and Trucco, M

Abstract

Background. α1,3-galactosyltransferase (α1,3GT) is an enzyme that produces carbohydrate chains termed αGal epitopes found in most mammals, although some species of higher primates, including human, are notable exceptions. The evolutionary origin of the lost α1,3GT enzyme activity is not yet known, although it has been suggested that the promoter activity of this gene in the ancestors of higher primates was inactivated. Methods. We used 5'-or 3'-RACE, GenomeWalking, reverse transcriptase polymerase chain reaction (RT-PCR) and dual Luciferase reporter assay for identification of the full-length cDNA, which includes the transcription initiation site and the promoter region of porcine α1,3GT gene. Results. The region around exon 1 is guanine and cytosine (GC)-rich (about 70%), comprising a CpG island spanning more than 1.5 kbp. The 5'-flanking region of exon 1 contains multiple transcription factor consensus motifs, including GC-box, SP1, AP2, and GATA-box sites, in the absence of TATA or CAAT-box sequences. The entire gene consists of three 5' noncoding and six coding region exons spanning more than 52 kbp. Detailed analysis of α1,3GT transcripts revealed two major alternative splicing patterns in the 5'-untranslated region (5'-UTR) and evidence for minor splicing activity that occurs in a tissue-specific manner. Interspecies comparison of 5'-UTR shows minimal homology between porcine and routine sequences except for exon 2, which suggests that the regulatory regions differ among species. Conclusions. These observations have important implications for experiments involving genetic manipulation of the α1,3GT gene in transgenic animals in terms of promoter utilization, and particularly in genetically engineering cells for the animal cloning technology by nuclear transfer.

Published
2000

48. Low-temperature single crystal reflection spectra of forsterite

Author

Suto, H., primary, Sogawa, H., additional, Tachibana, S., additional, Koike, C., additional, Karoji, H., additional, Tsuchiyama, A., additional, Chihara, H., additional, Mizutani, K., additional, Akedo, J., additional, Ogiso, K., additional, Fukui, T., additional, and Ohara, S., additional

Published
2006
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results