1,510 results on '"S. Koga"'
Search Results
2. New DTI protocol improves visualization of brain-tumor interface
- Author
-
S. Koga and M. Marinescu
- Subjects
Neurology. Diseases of the nervous system ,RC346-429 - Published
- 2022
- Full Text
- View/download PDF
3. Development and plasma characterization of an 850 MHz surface-wave plasma source
- Author
-
B. B. Sahu, S. Koga, H. Toyoda, and Jeon G. Han
- Subjects
Physics ,QC1-999 - Abstract
This work presents a simple design of surface wave plasma (SWP) source based on cylindrical cavity excited by ∼ 850 MHz ultra high frequency (UHF) wave. The cavity equipped with four rectangular slots demonstrates the usefulness of a large aperture coupling for plasma generation using top-wall excitation. The UHF power is coupled to the plasma through an upper dielectric wall placed at the open end of a coaxial transmission line that is short-circuited at the other end to construct a coaxial transmission line resonator. Using high-frequency microwave simulation the structure of the cylindrical cavity and the slots are designed and fabricated. Numerous plasma diagnostic methods are used to study the plasma characteristics and the mechanism of surface wave (SW) plasma generation. The plasma generation capability of the source is investigated at various operating pressures and UHF powers. It is seen that reasonably radial uniform plasmas with a very high plasma density ∼ 1011 cm-3 can be produced by a wide variation of pressures from 10 mTorr to 180 mTorr. Further, the usefulness of this UHF plasma source for large area plasma application is realized.
- Published
- 2017
- Full Text
- View/download PDF
4. A point mutation in the bile acid biosynthetic enzyme sterol 27-hydroxylase in a family with cerebrotendinous xanthomatosis.
- Author
-
N. Nakashima, Y. Sakai, H. Sakai, T. Yanase, M. Haji, F. Umeda, S. Koga, T. Hoshita, and H. Nawata
- Subjects
Biochemistry ,QD415-436 - Abstract
Cerebrotendinous xanthomatosis (CTX) is a rare familial disorder characterized by progressive neurological dysfunction, atherosclerosis, and xanthomas with sterol storage in the nervous system, vessels, and tendons. Increased serum cholestanol, derived from intermediates of cholesterol catabolism, may possibly be a major cause of the disease. An examination was made of the cDNA encoding cytochrome P450 sterol 27-hydroxylase (CYP27) in hepatic mitochondria, considered a defective enzyme inducing CTX, in a Japanese housewife afflicted with CTX and her family. The proposita and one of her brothers, who also had CTX symptoms and hypercholestanolemia, were found to be homozygotic, carrying a point mutation in the CYP27 gene at Arg104 (CGG) to Trp104 (TGG). The mutant position has a 100% conserved positive charge in all known vertebrate cytochrome P450s and even in bacterial cytochrome P450cam. The mother of the proposita and another brother were both free of CTX symptoms and were heterozygotic for the mutation, although their plasma cholesterol increased moderately. An increase in plasma cholestanol alone would, thus, not appear to be a direct cause of sterol storage in CTX, while CTX is strongly suggested to be caused by defects in both alleles of the CYP27 gene.
- Published
- 1994
- Full Text
- View/download PDF
5. 535. Detection of causative genes for resistance against cardiomyopathy syndrome in Atlantic salmon using omics data
- Author
-
M.L. Aslam, S. Gonen, S.A. Boison, E. Leder, M. Baranski, A. Norris, N. Robinson, S. Koga, T.K.K. Østbye, and B. Dagnachew
- Published
- 2022
- Full Text
- View/download PDF
6. Trophic and immunomodulatory effects of adipose tissue derived stem cells in a preclinical murine model of endometriosis
- Author
-
Toyofumi, Hirakawa, Fusanori, Yotsumoto, Naoto, Shirasu, Chihiro, Kiyoshima, Daichi, Urushiyama, Kenichi, Yoshikawa, Kohei, Miyata, Masamitsu, Kurakazu, Kaori Azuma, Koga, Mikiko, Aoki, Kazuki, Nabeshima, Kaori S, Koga, Yutaka, Osuga, Hiroaki, Komatsu, Fuminori, Taniguchi, Tasuku, Harada, Shin'ichiro, Yasunaga, and Shingo, Miyamoto
- Subjects
Disease Models, Animal ,Mice ,Multidisciplinary ,Adipose Tissue ,Stem Cells ,Endometriosis ,Animals ,Humans ,Female ,Fibrosis - Abstract
Endometriosis, which exhibits enigmatic pathological features such as stromal fibrosis and proliferation of ectopic epithelial cells, is known as a refractory disease. Mesenchymal stem cells modulate the fibrosis in stromal tissues through their trophic and immunomodulatory properties. To investigate the potential of stem cells in treating endometriosis, we examined the secondary morphology and molecular alterations in endometriosis-like lesions after the administration of adipose tissue-derived stem cells (ASCs) to an experimental murine model of endometriosis. The infused ASCs were found integrated in the endometriosis-like lesions. Accompanied by the suppression of stromal fibrosis and proliferation of endometriotic epithelial cells, the infusion of ASCs with stemness potential (early passage of ASCs) suppressed the growth of endometriosis-like lesions and inhibited the expression of pro-inflammatory and pro-fibrotic cytokines, whereas no significant attenuation of endometriosis-like lesions occurred after the infusion of ASCs without stemness potential (late passage of ASCs). Accordingly, the trophic and immunomodulatory properties of ASCs may regulate fibrosis in endometriosis-like lesions, suggesting that regenerative medicine could be recognized as an innovative treatment for patients with endometriosis through the accumulation of evidence of preclinical efficacy.
- Published
- 2022
- Full Text
- View/download PDF
7. P386Comparison of whether a beginner can be close to an expert with an artificial neural network in myocardial perfusion imaging
- Author
-
A Chiba, T Kudo, R Ideguchi, M Altay, S Koga, T Yonekura, A Tsuneto, M Morikawa, S Ikeda, H Kawano, Y Koide, M Uetani, and K Maemura
- Subjects
Radiology, Nuclear Medicine and imaging ,General Medicine ,Cardiology and Cardiovascular Medicine - Published
- 2019
- Full Text
- View/download PDF
8. Gene Expression Analysis of Activated Human ILC2s Based on 'Single Cell Secretion Activity Analysis System (LCI-S)'
- Author
-
M. Kuwae, Yumiko Tanaka, Yoshitaka Shirasaki, Y. Araki, Masako Matsusaka, T. Kikawada, S. Koga, Kouichi Fukunaga, S. Moro, Mai Yamagishi, K. Moro, Takashi Kamatani, and Kaede Miyata
- Subjects
Chemistry ,Gene expression ,Secretion ,Cell biology - Published
- 2019
- Full Text
- View/download PDF
9. 691 High Serum Testosterone is Associated with Poor Pathological Outcomes in Patients with Prostate Cancer in Japanese Populations
- Author
-
Y. Horiguchi, N. Sakamoto, F. Tsukuda, and S. Koga
- Subjects
Oncology ,medicine.medical_specialty ,business.industry ,Urology ,Endocrinology, Diabetes and Metabolism ,High serum ,Testosterone (patch) ,medicine.disease ,Psychiatry and Mental health ,Prostate cancer ,Endocrinology ,Reproductive Medicine ,Internal medicine ,medicine ,In patient ,business ,Pathological - Published
- 2018
- Full Text
- View/download PDF
10. Clinical result of helical tomotherapy for high-risk and very high-risk prostate cancer at single institution
- Author
-
Y. Horiguchi, Y. Hama, F. Tsukuda, S. Koga, N. Sakamoto, and A. Ogata
- Subjects
medicine.medical_specialty ,Prostate cancer ,business.industry ,Urology ,medicine.medical_treatment ,Medicine ,Radiology ,Single institution ,business ,medicine.disease ,Very high risk ,Tomotherapy - Published
- 2019
- Full Text
- View/download PDF
11. Development of a Vehicle Abnormal Behaviour Detection System
- Author
-
S. Koga, K. Miyakawa, M. Kageyama, and N. Shimada
- Published
- 2016
- Full Text
- View/download PDF
12. Study of a micro-roughness probe with ultrasonic sensor
- Author
-
A. Saito, S. Koga, and K. Hidaka
- Subjects
Engineering ,business.industry ,Mechanical Engineering ,Tracing ,Industrial and Manufacturing Engineering ,Mechanism (engineering) ,Micro roughness ,Optics ,Control system ,Ultrasonic vibration ,Evaluation methods ,Ultrasonic sensor ,business ,Non-contact atomic force microscopy - Abstract
This paper presents a micro-roughness measuring probe which involves an ultrasonic vibration sensor in a longitudinal tapping mode. This sensor is controlled by a measuring force control system. The combination of a fine and coarse driving mechanism realizes non-destructive, accurate and high-speed measurement. The measuring force is 1 μN to 1 mN with 1 kHz maximum dynamic response in the vertical axis. A mechanical structure, the characteristics of it and an evaluation method of the measuring force are described in the paper. Several results, for instance the surface damage after tracing and micro-roughness measurement, are shown.
- Published
- 2008
- Full Text
- View/download PDF
13. Temperature Dependency of Levitation Force and Its Relaxation in HTS
- Author
-
Naomichi Sakai, S. Koga, E. Ito, T. Suzuki, Koichiro Sawa, Izumi Hirabayashi, Hiroshi Seino, T. Sakai, Yoshiki Miyazaki, Ken Nagashima, and Masato Murakami
- Subjects
Superconductivity ,High-temperature superconductivity ,Materials science ,Condensed matter physics ,Relaxation (NMR) ,Magnetic bearing ,Superconducting magnet ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,Magnetic field ,law ,Condensed Matter::Superconductivity ,Levitation ,Electrical and Electronic Engineering ,Magnetic levitation - Abstract
High-temperature superconductors (HTS) have high potential for various engineering applications such as a superconducting flywheel energy storage system. The attractive feature of the superconducting magnetic bearings in the energy storage system is a reduction in the rotational loss. In this study, we studied the feasibility of a superconducting magnet to support bulk superconductors in magnetic bearings with the aim of increasing the stored energy. The superconducting magnet has a room temperature bore of 100 mm with the maximum magnetic field of 3.5 T. In addition, we used a GM freezer (10 K in the lowest attainment temperature), which can control the temperature of the bulk superconductors. The used bulk samples were Y-Ba-Cu-O and Sm-Ba-Cu-O 46 mm in diameter and 15 mm in thickness fabricated with a top-seeded melt-growth process. We have studied the effects of the temperature and magnetic field on the levitation force and its time relaxation. The levitation forces were measured by applying the magnetic fields of 0-2 T at 10-77.3 K. It was found that the levitation force increased with lowering temperature in both samples. The time relaxation of the levitation force was also reduced with lowering temperature. Sm-Ba-Cu-O exhibited better performance in the levitation force and its time relaxation in a high temperature and high-field region.
- Published
- 2007
- Full Text
- View/download PDF
14. Characteristic Evaluation of High Corrosion Resistant Ti/ (Pt + B2O3) Electrode with New Microstructure of Coat
- Author
-
Pei Bian, S. Koga, Dong Ying Ju, and Takashi Mitamura
- Subjects
Electrolysis ,Auxiliary electrode ,Materials science ,Mechanical Engineering ,Metallurgy ,chemistry.chemical_element ,Sulfuric acid ,engineering.material ,Microstructure ,Anode ,law.invention ,chemistry.chemical_compound ,chemistry ,Coating ,Chemical engineering ,Mechanics of Materials ,law ,Electrode ,engineering ,General Materials Science ,Titanium - Abstract
In order to improve the durability of Pt coated Ti electrodes as an anode of the sulfuric acid system electrolysis, tantalum oxide (Ta2O5) additions have been used widely. However that is not enough for uses under severe conditions. In this study,boric acid (H3BO3) was added into the Pt coating during manufacturing process of Ti/Pt-coated electrodes, and the (Pt + B2O3)/Ti electrodes were obtained. The effect of H3BO3 addition on the microstructure, surface area, and lifetime of (Pt + B2O3)/Ti electrodes was also investigated in detail. Commercially available titanium plates (10 100.5mm) were employed for prepare Ti/ (Pt + B2O3) electrodes, where it was confirmed by XRD that B2O3 formed by heating the boric acid was amorphous in the temperature range of 250 to 550. The coating solution of 2 μl of H2PtCl66H2O (Pt:50 g/l) dissolved in butanol and 5~20 mass% H3BO3 mixture was spread over the etched Ti plates. After drying at 70 for 30 min, the substances were heated at 250 to 550 for 10 min. The lifetime of the electrodes was examined by a direct current of 1 A using Pt plate as the counter electrode in 1 M H2SO4 solution at 40. The end of life was determined as the time when the cell voltage changed 2 times of the beginning.
- Published
- 2006
- Full Text
- View/download PDF
15. Study of colloidal stability of allophane dispersion by dynamic light scattering
- Author
-
S. Koga, M. Inada, Yasuhisa Adachi, and Motoyoshi Kobayashi
- Subjects
Colloid ,Electrophoresis ,Colloid and Surface Chemistry ,Chromatography ,Dynamic light scattering ,Ionic strength ,Chemical physics ,Chemistry ,Charge density ,Allophane ,Dispersion (chemistry) ,Suspension (chemistry) - Abstract
The aggregation kinetics of the aqueous dispersion of allophane was measured by dynamic light scattering as functions of pH and ionic strength. The sample was purified from natural Kanuma soil (Tochigi, Japan). A notable feature is that the dispersion is composed of aggregated flocs of allophane particles. The experiments were performed adjusting the initial floc diameter by centrifugation. The aggregation was induced by charge neutralization or compression of the electrical double layers, by merely mixing the suspension with an electrolyte solution of controlled pH and ionic strength. After the initial mixing operation, the suspension was placed in a static condition and the temporal variation of the average hydrodynamic diameter was monitored in situ . In the initial stage, the diameter dramatically increased reflecting the aggregation induced by the hydrodynamic mixing. Due to the Brownian aggregation, this initial enhancement was followed by a moderate increase. Under the Brownian aggregation, the aggregation rates were found to take a certain limiting value denoting fast coagulation irrespective of charge neutralization or compression of the electric double layers. When the salt concentration is not sufficiently high, the rate of aggregation against pH gradually increases and approaches the fast-coagulation domain; however, the rate decreases rather rapidly as the pH increases. This behavior was interpreted considering pH-dependent charge distribution generated on the surface of allophane particles with peculiar morphology. This interpretation was supported by electrophoretic mobility data. In contrast with the Brownian aggregation, the rate of orthokinetic aggregation induced by charge neutralization was detected to be slightly faster than that induced by compression of the electric double layers.
- Published
- 2005
- Full Text
- View/download PDF
16. Growth of high-quality AlN with low pit density on SiC substrates
- Author
-
S. Koga, Yuzo Furukawa, Hiroo Yonezu, and Akira Nakajima
- Subjects
Inorganic Chemistry ,Crystallography ,Materials science ,Impurity ,Etching (microfabrication) ,Atomic force microscopy ,Optimum growth ,Materials Chemistry ,Analytical chemistry ,Condensed Matter Physics ,Layer (electronics) ,Rocking curve ,Molecular beam epitaxy - Abstract
We investigated the optimum growth condition and initial growth process of AlN on 6H-SiC(0 0 0 1) substrates prepared by H 2 etching in the plasma-assisted molecular beam epitaxy (MBE). In X-ray rocking curve measurements, a small full-width at half-maximum of about 50 arcsec was obtained for a 150 nm thick AlN layer. The AlN layers have contained a lot of pits over a grown surface. Pit densities were markedly decreased by reducing the amount of residual impurities (O, OH and H 2 O) in an MBE chamber. A very low pit density of 10 4 –10 5 cm −2 was realized.
- Published
- 2004
- Full Text
- View/download PDF
17. SiC substrate defects and III-N heteroepitaxy
- Author
-
Benjamin Poust, Mike Wojtowicz, A. Khan, Benjamin Heying, Mark S. Goorsky, R. Sandhu, R. Hsing, and T S Koga
- Subjects
Materials science ,Acoustics and Ultrasonics ,business.industry ,Scattering ,Mineralogy ,Heterojunction ,Substrate (electronics) ,Condensed Matter Physics ,Epitaxy ,Crystallographic defect ,Micropipe ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Optoelectronics ,Dislocation ,business ,Molecular beam epitaxy - Abstract
This study addressed how defects in SiC substrates influence the crystallographic properties of AlGaN/GaN layers deposited by metallorganic vapour phase epitaxy and by molecular beam epitaxy. We employed double crystal reflection x-ray topography using symmetric (0008) and (00012) reflections with CuKα radiation (λ = 1.54 A) to image dislocations, micropipes, and low angle boundaries in SiC substrates. Lattice strain near the core of a micropipe defect was estimated to be of the order of 10−7. The substrates investigated exhibited radial patterns of strain and, primarily, of tilt of the order of tens of arcsec. After deposition of the AlGaN and GaN layers, DCXRT images were generated from the substrate (0008) or (00012) and GaN epitaxial layer (0004) reflections. Full-width at half-maximum values ranging from ~100 to 300 arcsec were typical of the GaN reflections, while those of the 4H–SiC reflections were ~20–70 arcsec. Micropipes, tilt boundaries, and inclusions in the SiC were shown to produce structural defects in the GaN layers. A clear correlation between SiC substrate defects and GaN defects has been established.
- Published
- 2003
- Full Text
- View/download PDF
18. Appearance of symptoms in melon inoculated with a pathogenic Streptomyces sp. causing root tumors
- Author
-
Masahiro Yoshida, T. Yamaguchi, S. Koga, and K. Kobayashi
- Subjects
Horticulture ,biology ,Inoculation ,Melon ,Botany ,biology.organism_classification ,Streptomyces - Abstract
メロンがんしゅ病放線菌接種後のメロンの病徴発現様相を調べ,接種方法と発病との関係,メロンの生育ステージと発病との関係およびメロンの地上部組織における病原性発現の特徴について検討した.栽培中の株元土壌に灌注接種したメロンと汚染土壌に播種したメロンでの本病の潜伏期間は約7∼14日であった.また,汚染土壌に直接播種したメロンの方がより激しく発病した.こぶ組織は根の分岐部に多くみられ,特に汚染土壌に播種したメロンの最初のこぶ形成部位は主根と一次分枝根の分岐部であり,その後,さらに高次の分枝根の分岐部でも認められた.こぶの形成数は,播種42日後頃までは著しく増加したが,49日後頃からは新しいこぶの形成は減少した.罹病メロンは播種49日後までに,草丈で約40%,葉数で約15%の生育抑制を受けた.異なった生育ステージのメロンへの接種後の病徴発現では,播種後14日齢のメロンで最も激しく発病し,それ以上では加齢とともに発病が軽減された.これらの病徴発現の特徴から,本病の病徴はメロンが若く根系の発達が著しい時期に激しく現れるように考えられた.一方,本病原放線菌は菌体の注入接種によりメロンの地上部組織でも,接種組織の肥大を呈する病徴を起こした.この病徴の発現は胚軸で最も早く激しく現れ,次いで茎,葉柄の順であり,胞子体より菌糸体での接種においてより顕著に現れた.
- Published
- 2003
- Full Text
- View/download PDF
19. Japan's superconducting Maglev train
- Author
-
M. Ono, H. Ohtsuki, and S. Koga
- Subjects
Engineering ,business.industry ,Superconducting magnet ,Linear motor ,Propulsion ,Automotive engineering ,law.invention ,Test line ,Electromagnetic coil ,law ,Maglev ,Electrical and Electronic Engineering ,business ,Instrumentation ,Magnetic levitation ,Armature (electrical engineering) - Abstract
We have developed a Maglev train under the guidance of the Japanese Ministry of Transport. The Maglev train is an advanced train that can run more than 500 km/h with a linear synchronous motor (LSM) that has both a superconducting magnet on board and an armature coil in the ground. The Maglev train was tested on the Yamanashi Maglev test line. Tests began in 1997, which exercised various functions of performance. The main results of the tests are reported in this article.
- Published
- 2002
- Full Text
- View/download PDF
20. Development and plasma characterization of an 850 MHz surface-wave plasma source
- Author
-
S. Koga, Bibhuti Bhusan Sahu, Hirotaka Toyoda, and Jeon G. Han
- Subjects
010302 applied physics ,Dense plasma focus ,Chemistry ,Waves in plasmas ,business.industry ,Plasma etcher ,Analytical chemistry ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,lcsh:QC1-999 ,Plasma window ,Optics ,Physics::Plasma Physics ,0103 physical sciences ,Physics::Space Physics ,Plasma diagnostics ,Electromagnetic electron wave ,Capacitively coupled plasma ,Inductively coupled plasma ,0210 nano-technology ,business ,lcsh:Physics - Abstract
This work presents a simple design of surface wave plasma (SWP) source based on cylindrical cavity excited by ∼ 850 MHz ultra high frequency (UHF) wave. The cavity equipped with four rectangular slots demonstrates the usefulness of a large aperture coupling for plasma generation using top-wall excitation. The UHF power is coupled to the plasma through an upper dielectric wall placed at the open end of a coaxial transmission line that is short-circuited at the other end to construct a coaxial transmission line resonator. Using high-frequency microwave simulation the structure of the cylindrical cavity and the slots are designed and fabricated. Numerous plasma diagnostic methods are used to study the plasma characteristics and the mechanism of surface wave (SW) plasma generation. The plasma generation capability of the source is investigated at various operating pressures and UHF powers. It is seen that reasonably radial uniform plasmas with a very high plasma density ∼ 1011 cm-3 can be produced by a wide variation of pressures from 10 mTorr to 180 mTorr. Further, the usefulness of this UHF plasma source for large area plasma application is realized.
- Published
- 2017
21. Influence of exercise training with thigh compression on heat-loss responses
- Author
-
T, Amano, Y, Inoue, S, Koga, T, Nishiyasu, and N, Kondo
- Subjects
Adult ,Male ,Hot Temperature ,Acclimatization ,Sweating ,Bicycling ,Vasodilation ,Oxygen Consumption ,Thigh ,Compression Bandages ,Humans ,Exercise ,Body Temperature Regulation ,Skin - Abstract
We investigated the effect of thigh compression, which accelerates activation of central command and muscle metabo- and mechanoreceptors, on the adaptation of sweating and cutaneous vascular responses during exercise heat acclimation. Nine non-heat-acclimated male subjects were acclimated to heat (32 °C and 50% RH) while cycling [50% of maximum oxygen uptake ( V ˙ O 2 m a x )] 60 min/day for 7 days (control group). The experimental group (n = 9) conducted the same training while the proximal thighs were compressed by a cuff at 60 mmHg. V ˙ O 2 m a x , acetylcholine-induced forearm sweating rate (iontophoresis), and mean sweating and cutaneous vascular responses on the forehead, chest, and forearm (SRmean and CVCmean ) during passive heating were evaluated before and after training. Training significantly increased V ˙ O 2 m a x while did not affect acetylcholine-induced sweating rates in either group. Training significantly decreased Tb thresholds for SRmean and CVCmean during passive heating without the alternations of sensitivities in both groups. Although SRmean during passive heating at a given ΔTb was not improved in either group, CVCmean was significantly (P 0.05) attenuated after exercise training only in experimental group. Our results indicate that thigh cuff compression during exercise heat acclimation does not influence adaptation of the sweating response but attenuate cutaneous vasodilation.
- Published
- 2014
22. The Repairing Method of Impervious Sheet by Geosynthetic Clay Liner in the Water
- Author
-
S. Ichiyasu, K. Mizuno, S. Koga, S. Takakashi, K. Haziri, and A. Yokota
- Subjects
Geosynthetic clay liner ,Impervious surface ,Geotechnical engineering ,Geology - Published
- 1999
- Full Text
- View/download PDF
23. An anti-loosening screw-fastener innovation and its evaluation
- Author
-
H. Fujii, N. Sase, S Koga, and K Nishioka
- Subjects
Nut ,Engineering ,business.product_category ,business.industry ,Metals and Alloys ,Torsion (mechanics) ,Thread (computing) ,Structural engineering ,Fastener ,Industrial and Manufacturing Engineering ,Computer Science Applications ,Screw thread ,Modeling and Simulation ,Bearing surface ,Screw ,Ceramics and Composites ,Threaded fastener ,business - Abstract
It is widely known that screw fasteners loosen sooner or later, even so-called anti-loosening screw fasteners available in the market do not prevent loosening, as reported in an earlier paper. The purpose of this paper is to present the development of a real anti-loosening screw fastener that has a strong resistance against loosening without sacrificing any of the advantageous features of conventional screw fasteners. Before introducing the development, the mechanism of the loosening process of screw fasteners is investigated. It is shown that the loosening of screw fasteners is caused by two factors. One is relative slip between the bolt and nut screw threads, the slip causing torsion in the bolt. The other is relative slip between the bearing surface of the bolt or nut and the surface of the fastened material, the slip causing slackening of the torsion. The prevention of loosening should be possible if either one of these causes is eliminated. Aiming at eliminating the first cause, the torsion, a new screw named `The Step-Lock Bolt' (SLB) is developed. The developed bolt has eight steps in which the lead angle degree is nil at the circumference of the thread. The efficacy in preventing the initiation and progress of loosening is examined by applying a force cyclically at right angles to the center line of a bolt. The results show that whilst a conventional fastener lost the fastening force within 1000 cycles, the developed SLB does not lose the fastening force until over 30 000 cycles. It may thus be concluded that the SLB is a practical means of preventing screw fastener loosening.
- Published
- 1998
- Full Text
- View/download PDF
24. Nucleoside Oxidase, a Hydrogen Peroxide-Forming Oxidase, from Flavobacterium meningosepticum
- Author
-
H. Yamada, Y.-M. Choi, L.-Y. Cheng, J. Ogawa, S. Koga, and S. Shimizu
- Subjects
chemistry.chemical_classification ,Gel electrophoresis ,Flavin adenine dinucleotide ,Ecology ,Stereochemistry ,Guanosine ,Cytidine ,Nucleoside oxidase ,Biology ,Applied Microbiology and Biotechnology ,Uridine ,chemistry.chemical_compound ,chemistry ,medicine ,biology.protein ,Nucleotide ,Inosine ,Research Article ,Food Science ,Biotechnology ,medicine.drug - Abstract
A novel enzyme which catalyzes the oxidation of nucleosides to nucleoside-5(prm1)-carboxylic acids, forming hydrogen peroxide, was purified to homogeneity from Flavobacterium meningosepticum T-2799. The enzyme has a molecular weight of about 500,000, and four nonidentical subunits (molecular weights of 81,000, 69,000, 33,000, and 16,000) were detected on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. On the basis of visible absorption spectra of the purified enzyme, the enzyme is concluded to be a hemoprotein. It also contains covalently bound flavin adenine dinucleotide. The various nucleosides, such as adenosine (K(infm) = 48 (mu)M), inosine (K(infm) = 66 (mu)M), guanosine (K(infm) = 21 (mu)M), thymidine (K(infm) = 50 (mu)M), uridine (K(infm) = 80 (mu)M), and cytidine (K(infm) = 50 (mu)M), were oxidized by the enzyme, but nucleotides, bases, and ribose were not.
- Published
- 1997
- Full Text
- View/download PDF
25. Dynamics of Respiratory Response to Sinusoidal Work Load in Humans
- Author
-
Yoshiyuki Fukuoka, S. Koga, M. Shigematsu, Y. Fukuba, and H. Ikegami
- Subjects
Adult ,Male ,Work ,Time Factors ,Nitrogen ,Physical Exertion ,Physical Therapy, Sports Therapy and Rehabilitation ,Physical exercise ,Models, Biological ,Transfer function ,Mass Spectrometry ,Oxygen Consumption ,Computer Systems ,Distortion ,Humans ,Orthopedics and Sports Medicine ,Mathematics ,Pulmonary Gas Exchange ,Respiration ,Work (physics) ,Time constant ,Reproducibility of Results ,Mechanics ,Carbon Dioxide ,Exponential function ,Oxygen ,Nonlinear system ,Nonlinear Dynamics ,Physical Fitness ,Exercise Test ,Breathing ,human activities ,circulatory and respiratory physiology - Abstract
The present study was undertaken to investigate possible distortion in responses of respiratory variables including O2 uptake (VO2), CO2 output (VCO2), and ventilation (VE) to sinusoidal work load, and to find out whether the conventional transfer models were applicable to analyze the dynamics of these variables. Six healthy subjects performed exercise for 32 min on a bicycle ergometer with electro-magnetic braking. The work load was varied sinusoidally between 30 W and 60% of maximum O2 uptake (VO2max) during periods from 1 to 16 min. The respiratory variables were measured on a breath-by-breath basis with a mass spectrometer and a computer system. The responses of VO2, VCO2, and VE to sinusoidal work load were not completely sinusoidal in form but were somewhat distorted, forming saw-tooth waves with steeper down-slopes during periods of 4-16 min, but this distortion was not observed at 1 min or 2 min periods. However, the results could be approximately described by a first-order model without or with time delay. Time constants of the first-order model without time delay were 46 sec for VO2, 62 sec for VCO2, and 73 sec for VE, respectively. We also found a close relationship between the time constants of VO2 and VCO2 and VO2max. These results suggested that exponential functions may be applied and are expected to yield valid results in assessing physical fitness, although the control of ventilatory and gas exchange in exercise does show non-linear characteristics.
- Published
- 1997
- Full Text
- View/download PDF
26. A fuzzy-Gaussian neural network and its application to mobile robot control
- Author
-
Keigo Watanabe, S. Koga, Jun Tang, Masatoshi Nakamura, and Toshio Fukuda
- Subjects
Artificial neural network ,Computer science ,Mobile robot ,Control engineering ,Fuzzy control system ,Fuzzy logic ,symbols.namesake ,Control and Systems Engineering ,Control theory ,Control system ,Gaussian function ,symbols ,Electrical and Electronic Engineering ,Membership function - Abstract
A fuzzy-Gaussian neural network (FGNN) controller is described by applying a Gaussian function as an activation function. A specialized learning architecture is used so that membership function can be tuned without using expert's manipulated data. As an example of the application, a tracking control problem for the speed and azimuth of a mobile robot driven by two independent wheels is solved by using the FGNN controller. To simplify the implementation of the FGNN controller for the two-input/two-output controlled system, a learning controller is utilized consisting of two FGNN's based on independent reasoning and a connection net with fixed weights. The effectiveness of the proposed method is illustrated by performing the simulation of a circular or square trajectory tracking control.
- Published
- 1996
- Full Text
- View/download PDF
27. Evaluation of anti-loosening nuts for screw fasteners
- Author
-
H. Fujii, N. Sase, K. Nishioka, and S. Koga
- Subjects
Nut ,business.product_category ,business.industry ,Metals and Alloys ,Structural engineering ,Flange ,Fastener ,Industrial and Manufacturing Engineering ,Computer Science Applications ,Modeling and Simulation ,Ceramics and Composites ,Composite material ,business ,Mathematics ,High acceleration - Abstract
There are various types of screw fasteners and/or parts with additional features designed to prevent loosening. Their actual ability is questioned and concretely examined. Seven types of those so-called anti-loosening nuts which are readily available in the market are compared with conventional nuts and evaluated their ability, including their manoeuvrability. Two types of loosening devices are developed for this purpose. One is to loosen fasteners by forcing a fastened material to displace and the other by applying high acceleration to a whole structure. The conclusions obtained are as follows: (1) Nuts with edged spring at the bottom, nylon inserted nuts, metal inserted nuts and rings with sharp inner edge to cover nuts are all unable to stop loosening. (2) A nut with serrated flange at the bottom has the ability to suppress the initiation of loosening to some extent. It makes the fastener resistant to higher levels of acceleration than fine screws. (3) A pair of double nuts and a combination of a nut with an eccentric external taper and a nut with an internal taper can slow the loosening process considerably. The latter may be an answer at present, but it is effective only under limited conditions.
- Published
- 1996
- Full Text
- View/download PDF
28. Present and future of nematode control in greenhouse vegetable production
- Author
-
S. Koga
- Subjects
Nematode ,Agronomy ,Production (economics) ,Greenhouse ,Biology ,biology.organism_classification - Published
- 1995
- Full Text
- View/download PDF
29. Endoscopic removal of herniated nucleus pulposus migrated dorsally to the dural sac
- Author
-
S, Koga, K, Sairyo, T, Kon, I, Shibuya, Y, Kanamori, T, Kosugi, R, Konno, T, Arai, and A, Dezawa
- Subjects
Male ,Lumbar Vertebrae ,Humans ,Endoscopy ,Dura Mater ,Middle Aged ,Intervertebral Disc Displacement - Abstract
A herniated nucleus pulposus (HNP) migrated dorsally to the dural sac is a rare condition. Here, we present a case, in which the HNP was removed with minimally invasive spinal endoscopy. A 54-year-old man presented complaining of left leg pain and paresis. Neurologic findings and an MRI suggested an epidural tumor or a dorsally migrated HNP compressing the S1 nerve root and dural sac. With a spinal endoscope, careful laminotomy of caudal L5 and cranial S1 was made. En bloc flavectomy exposed a mass covered with a thin capsule. The mass was identified as a dorsally migrated HNP. After complete HNP fragment removal, the dural sac and S1 nerve root were decompressed. Immediately postoperative, the leg pain subsided and motor function normalized, although the patient complained of numbness at the S1 dermatome area. In summary, a large HNP that had migrated dorsally to the dural sac was successfully removed endoscopically.
- Published
- 2012
30. Minimally invasive removal of a recurrent lumbar herniated nucleus pulposus by the small incised microendoscopic discectomy interlaminar approach
- Author
-
S, Koga, K, Sairyo, I, Shibuya, Y, Kanamori, T, Kosugi, H, Matsumoto, Y, Kitagawa, T, Sumita, and A, Dezawa
- Subjects
Adult ,Male ,Lumbar Vertebrae ,Recurrence ,Humans ,Diskectomy, Percutaneous ,Endoscopy ,Female ,Intervertebral Disc Displacement - Abstract
In this report, we introduce two cases of recurrent herniated nucleus pulposus (HNP) at L5-S1 that were successfully removed using the small incised microendoscopic discectomy (sMED) technique, proposed by Dezawa and Sairyo in 2011. sMED was performed via the interlaminar approach with a percutaneous endoscope. The patients had previously underdone microendoscopic discectomy for HNP. For the recurrent HNP, the sMED interlaminar approach was selected because the HNP occurred at the level of L5-S1; the percutaneous endoscopic transforaminal approach was not possible for anatomical reasons. To perform sMED via the interlaminar approach, we employed new, specially made devices to enable us to use this technique. In conclusion, sMED is the most minimally invasive approach available for HNP, and its limitations have been gradually eliminated with the introduction specially made devices. In the near future, percutaneous endoscopic surgery could be the gold standard for minimally invasive disc surgery.
- Published
- 2012
31. Analysis of H atoms in a negative ion source plasma with the non-equilibrium electron energy distribution function
- Author
-
T. Shibata, Katsuyoshi Tsumori, S. Koga, Akiyoshi Hatayama, N. Kameyama, M. Bacal, and R. Terasaki
- Subjects
Materials science ,Distribution function ,Physics::Plasma Physics ,Plasma ,Electron ,Atomic physics ,Instrumentation ,Electron ionization ,Dissociation (chemistry) ,Ion source ,Neutral beam injection ,Ion - Abstract
In negative ion sources for the neutral beam injection, it is important to calculate H atom flux onto the plasma grid (PG) surface for the evaluation of H(-) production on the PG surface. We have developed a neutral (H(2) molecules and H atoms) transport code. In the present study, the neutral transport code is applied to the analysis of the H(2) and H transport in a NIFS-RD ion source in order to calculate the flux onto the PG surface. Taking into account non-equilibrium feature of the electron energy distribution function (EEDF), i.e., the fast electron component, we have done the neutral transport simulation. The results suggest that the precise evaluation of the EEDF, especially in the energy range 15 eVE30 eV is important for the dissociation rate of H(2) molecules by the electron impact collision and the resultant H atom flux on the PG.
- Published
- 2012
32. Oxidation of Nucleic Acid Related Compounds by the Peroxodisulfate Ion
- Author
-
A. Nishino, S. Koga, T. Yoshitake, and Toshio Itahara
- Subjects
chemistry.chemical_classification ,chemistry.chemical_compound ,Reaction mechanism ,Chemistry ,Phosphate buffered saline ,Nucleic acid ,Nucleotide ,General Chemistry ,Combinatorial chemistry ,Thymine ,Ion - Abstract
The treatment of nucleic acid bases, nucleosides, and nucleotides with peroxodisulfate ion in a phosphate buffer solution at pH 7.0 or water at 70—75 °C was investigated. The reaction of thymine and 5-methylcytosine nucleosides and nucleotides resulted in the oxidation of the 5-methyl groups. The oxidation products from 1,3-dimethyluracils and the time-course of the reaction of uracils led to two plausible reaction mechanisms for the oxidation of uracils.
- Published
- 1994
- Full Text
- View/download PDF
33. Cardiac preservation is enhanced in a heterotopic rat transplant model by supplementing the nitric oxide pathway
- Author
-
M J Broekman, Jerold Brett, M C Oz, Hui Liao, Yoshifumi Naka, S Koga, Z. Taha, Aaron J. Marcus, Paul J. Cannon, and David J. Pinsky
- Subjects
Male ,Nitroprusside ,Transplantation, Heterotopic ,medicine.medical_treatment ,Ischemia ,Biosensing Techniques ,Pharmacology ,Arginine ,Bradykinin ,Nitric Oxide ,Nitric oxide ,Rats, Sprague-Dawley ,Nitroglycerin ,chemistry.chemical_compound ,medicine ,Animals ,Viaspan ,Cyclic GMP ,Heart transplantation ,biology ,Superoxide Dismutase ,business.industry ,Graft Survival ,Heart ,Organ Preservation ,General Medicine ,medicine.disease ,Coronary Vessels ,Rats ,Nitric oxide synthase ,Transplantation ,Endothelial stem cell ,Biochemistry ,chemistry ,Nitric Oxide Pathway ,biology.protein ,Heart Transplantation ,Amino Acid Oxidoreductases ,Nitric Oxide Synthase ,business ,Research Article ,Endocardium - Abstract
Nitric oxide (NO) is a novel biologic messenger with diverse effects but its role in organ transplantation remains poorly understood. Using a porphyrinic microsensor, the first direct measurements of coronary vascular and endocardial NO production were made. NO was measured directly in the effluent of preserved, heterotopically transplanted rat hearts stimulated with L-arginine and bradykinin; NO concentrations fell from 2.1 +/- 0.4 microM for freshly explanted hearts to 0.7 +/- 0.2 and 0.2 +/- 0.08 microM for hearts preserved for 19 and 38 h, respectively. NO levels were increased by SOD, suggesting a role for superoxide-mediated destruction of NO. Consistent with these data, addition of the NO donor nitroglycerin (NTG) to a balanced salt preservation solution enhanced graft survival in a time- and dose-dependent manner, with 92% of hearts supplemented with NTG surviving 12 h of preservation versus only 17% in its absence. NTG similarly enhanced preservation of hearts stored in University of Wisconsin solution, the clinical standard for preservation. Other stimulators of the NO pathway, including nitroprusside, L-arginine, or 8-bromoguanosine 3',5' monophosphate, also enhanced graft survival, whereas the competitive NO synthase antagonist NG-monomethyl-L-arginine was associated with poor preservation. Likely mechanisms whereby supplementation of the NO pathway enhanced preservation included increased blood flow to the reperfused graft and decreased graft leukostasis. NO was also measured in endothelial cells subjected to hypoxia/reoxygenation and detected based on its ability to inhibit thrombin-mediated platelet aggregation and serotonin release. NO became undetectable in endothelial cells exposed to hypoxia followed by reoxygenation and was restored to normoxic levels on addition of SOD. These studies suggest that the NO pathway fails during preservation/transplantation because of formation of oxygen free radicals during reperfusion, which quench available NO. Augmentation of NO/cGMP-dependent mechanisms enhances vascular function after ischemia and reperfusion and provides a new strategy for transplantation of vascular organs.
- Published
- 1994
- Full Text
- View/download PDF
34. Modeling of Neutrals and H[sup −] Transport in a Large Negative Ion Source
- Author
-
N. Kameyama, D. Matsushita, S. Koga, R. Terasaki, A. Hatayama, Yasuhiko Takeiri, and Katsuyoshi Tsumori
- Subjects
Magnetic filter ,Field (physics) ,Flow velocity ,Chemistry ,High velocity ,Monte Carlo method ,Extraction (chemistry) ,Atomic physics ,Ion source ,Ion - Abstract
A systematic study of the extraction probability of surface‐produced H− ions from the ion source has been done with H− and neutral Monte‐Carlo transport modeling. Without the effects of the flow velocity of background H+ ions and neutrals, the extraction probability (E.P.) depends strongly on the strength of the magnetic filter field BMF for the low gas pressure condition. On the other hand, the E.P. does not depend so much on BMF for the high gas pressure condition. Neutral transport modeling shows that H2 neutral possibly has a relatively high velocity (∼1 km/s). The effect on the E.P., however, is not significant even for the high gas pressure regime.
- Published
- 2011
- Full Text
- View/download PDF
35. [Significance of preoperative ultrasound evaluation of the forearm arteries prior to coronary artery bypass grafting]
- Author
-
M, Sato, E, Suenaga, S, Koga, and H, Kawasaki
- Subjects
Male ,Forearm ,Ulnar Artery ,Preoperative Care ,Radial Artery ,Tissue and Organ Harvesting ,Humans ,Female ,Coronary Artery Bypass ,Aged ,Ultrasonography - Abstract
We report the significance of preoperative ultrasound evaluation of the forearm arteries in coronary artery bypass grafting (CABG). Ultrasound evaluation was performed in 288 arms with negative Allen's test between August 2004 and July 2007. The diameter, the level of atherosclerotic changes and calcifications, and systolic velocities were evaluated in radial artery (RA) and ulnar artery (UA). The diameter of RA was 2.6 +/- 0.5 mm, and in 30 arms it was smaller than 2 mm. There were 2 occlusions, 4 stenoses, and 20 arteriosclerotic changes in RA. There were 1 occlusion, 8 stenoses, and 4 arteriosclerotic changes in UA. Since there were some overlaps in small diameter and poor qualities of RA and UA, 55 arms (19%) were considered not to qualify as candidates for RA harvest. Pre-operative ultrasound evaluation of the forearm arteries allows safer radial artery harvest and should be performed even in patients with negative Allen' s test.
- Published
- 2010
36. ChemInform Abstract: Oxidation of Thymidine by Peroxomono- and Peroxodisulfate Ions
- Author
-
S. Koga and Toshio Itahara
- Subjects
chemistry.chemical_compound ,chemistry ,Nucleic acid ,Organic chemistry ,heterocyclic compounds ,General Medicine ,Thymidine ,Ion - Abstract
Oxidation of thymidine by KHSO5 gave thymidine glycols, while a similar treatment with Na2S2O8 gave 5-hydroxymethyl-2′-deoxyuridine.
- Published
- 2010
- Full Text
- View/download PDF
37. ChemInform Abstract: Oxidation of Nucleic Acid Related Compounds by the Peroxodisulfate Ion
- Author
-
Toshio Itahara, A. Nishino, S. Koga, and T. Yoshitake
- Subjects
chemistry.chemical_classification ,Reaction mechanism ,chemistry.chemical_compound ,Chemistry ,Phosphate buffered saline ,Nucleic acid ,Organic chemistry ,Nucleotide ,General Medicine ,Ion ,Thymine - Abstract
The treatment of nucleic acid bases, nucleosides, and nucleotides with peroxodisulfate ion in a phosphate buffer solution at pH 7.0 or water at 70—75 °C was investigated. The reaction of thymine and 5-methylcytosine nucleosides and nucleotides resulted in the oxidation of the 5-methyl groups. The oxidation products from 1,3-dimethyluracils and the time-course of the reaction of uracils led to two plausible reaction mechanisms for the oxidation of uracils.
- Published
- 2010
- Full Text
- View/download PDF
38. Hypoxia-mediated induction of endothelial cell interleukin-1 alpha. An autocrine mechanism promoting expression of leukocyte adhesion molecules on the vessel surface
- Author
-
B A Wolitzky, C Norton, W Benjamin, Revati Shreeniwas, J Plocinski, E Kaiser, David J. Pinsky, M. Karakurum, Jerold Brett, and S Koga
- Subjects
Leukocyte adhesion molecule ,Molecular Sequence Data ,Intercellular Adhesion Molecule-1 ,Gene Expression ,In Vitro Techniques ,Mice ,E-selectin ,Cell Adhesion ,Tumor Cells, Cultured ,medicine ,Animals ,Humans ,RNA, Messenger ,Hypoxia ,Cell adhesion ,Autocrine signalling ,Cells, Cultured ,Base Sequence ,biology ,Cell adhesion molecule ,General Medicine ,Hypoxia (medical) ,Cell biology ,Endothelial stem cell ,Oligodeoxyribonucleotides ,Immunology ,biology.protein ,Endothelium, Vascular ,medicine.symptom ,E-Selectin ,Cell Adhesion Molecules ,Research Article ,Interleukin-1 - Abstract
Tissue injury that accompanies hypoxemia/reoxygenation shares features with the host response in inflammation, suggesting that cytokines, such as IL-1, may act as mediators in this setting. Human endothelial cells (ECs) subjected to hypoxia (PO2 approximately 12-14 Torr) elaborated IL-1 activity into conditioned media in a time-dependent manner; this activity was completely neutralized by an antibody to IL-1 alpha. Production of IL-1 activity by hypoxic ECs was associated with an increase in the level of mRNA for IL-1 alpha, and was followed by induction of endothelial-leukocyte adhesion molecule-1 and enhanced expression of intercellular adhesion molecule-1 (ICAM-1) during reoxygenation. During reoxygenation there was a three- to five-fold increased adherence of leukocytes, partly blocked by antibodies to endothelial-leukocyte adhesion molecule-1 and ICAM-1. Suppressing endothelial-derived IL-1, using either antibodies to IL-1 alpha, specific antisense oligonucleotides or the IL-1 receptor antagonist, decreased leukocyte adherence to reoxygenated ECs, emphasizing the integral role of IL-1 in the adherence phenomenon. Mice subjected to hypoxia (PO2 approximately 30-40 Torr) displayed increased plasma levels of IL-1 alpha, induction of IL-1 alpha mRNA in the lung, and enhanced expression of ICAM-1 in pulmonary tissue compared with normoxic controls. These data suggest that hypoxia is a stimulus which induces EC synthesis and release of IL-1 alpha, resulting in an autocrine enhancement in the expression of adhesion molecules.
- Published
- 1992
- Full Text
- View/download PDF
39. Synthesis and release of interleukin 1 by reoxygenated human mononuclear phagocytes
- Author
-
J Ryan, Satoshi Ogawa, Y Koga, Keisuke Kuwabara, W Benjamin, J Plocinski, D K Burns, Jerold Brett, J A Leavy, and S Koga
- Subjects
medicine.medical_treatment ,Molecular Sequence Data ,Biology ,Monocytes ,Mice ,chemistry.chemical_compound ,Hydroxides ,medicine ,Animals ,Humans ,Xanthine oxidase ,Cells, Cultured ,Phagocytes ,Base Sequence ,Hydroxyl Radical ,Interleukin-6 ,Tumor Necrosis Factor-alpha ,Monocyte ,Interleukin ,General Medicine ,Hypoxia (medical) ,medicine.disease ,Molecular biology ,Cell Hypoxia ,Oxygen tension ,medicine.anatomical_structure ,Cytokine ,chemistry ,Immunology ,Tumor necrosis factor alpha ,medicine.symptom ,Reperfusion injury ,Research Article ,Interleukin-1 - Abstract
To examine the possible involvement of cytokines in reperfusion injury, we have studied production of IL-1 by human vascular cells, including smooth muscle and mononuclear phagocytes. Exposure of cells to hypoxia (pO2 approximately 14 torr) followed by reoxygenation led to significant release of IL-1 only from the mononuclear phagocytes. Elaboration of IL-1 was dependent on the oxygen tension and duration of hypoxia (optimal at lower pO2s, approximately 14-20 torr, and after 9 h), as well as the time in reoxygenation (maximal IL-1 release at 6-9 h). Although a period of hypoxia was necessary for subsequent IL-1 production during reoxygenation of either peripheral blood monocytes or cultured monocyte-derived macrophages, no IL-1 release occurred during the hypoxic exposure. IL-1 released during reoxygenation was newly synthesized, and its production was triggered by the generation of oxygen free radicals, as it could be blocked by the addition of either allopurinol or free radical scavengers to cultures and could be stimulated in part by low concentrations of hydrogen peroxide or xanthine/xanthine oxidase. The potential pathophysiological effects of IL-1-containing supernatants from reoxygenated macrophages was shown by their induction of endothelial tissue factor and enhancement of endothelial adhesiveness for neutrophils, both of which could be blocked by anti-IL-1 antibody. The relevance of IL-1 to hypoxia/reoxygenation in vivo was suggested by the presence of circulating nanogram amounts of this cytokine in the plasma of mice during the reoxygenation period following a hypoxia.
- Published
- 1992
- Full Text
- View/download PDF
40. Calculous pyelonephritis
- Author
-
S. Koga, M. Matsuoka, C. Ohyama, and Y. Arakaki
- Subjects
Male ,Klebsiella ,medicine.medical_specialty ,Ureteral Calculi ,Urology ,Urine ,urologic and male genital diseases ,Gastroenterology ,Kidney Calculi ,Internal medicine ,Humans ,Medicine ,Blood culture ,Pyelonephritis ,biology ,medicine.diagnostic_test ,business.industry ,Septic shock ,Middle Aged ,biology.organism_classification ,medicine.disease ,female genital diseases and pregnancy complications ,Urinary obstruction ,Proteus ,Nephrology ,Bacteremia ,Female ,Calculous pyelonephritis ,business - Abstract
The authors report on 48 patients with calculous pyelonephritis. Urinary obstruction was caused by renal calculi in 21 patients and ureteral calculi in 27. Urine cultures were positive in 87.5% and bacteremia was seen in 70%. The common organisms in urine and blood culture were E. coli, Proteus and Klebsiella. Septic shock occurred in 10 (20.8%) out of 48 patients. Calculous pyelonephritis with urinary obstruction is a very serious condition.
- Published
- 1992
- Full Text
- View/download PDF
41. Occurrence of multiple aberrantly spliced mRNAs upon a donor splice site mutation that causes familial lipoprotein lipase deficiency
- Author
-
Toshiya Inaba, Shun Ishibashi, Y Furuichi, Takanari Gotoda, F Takaku, S Koga, Nobuhiro Yamada, Toshio Murase, Hitoshi Shimano, and Yoshio Yazaki
- Subjects
Adult ,Transcription, Genetic ,RNA Splicing ,Molecular Sequence Data ,Biology ,medicine.disease_cause ,Polymerase Chain Reaction ,Biochemistry ,Lipoprotein lipase deficiency ,medicine ,Humans ,splice ,RNA, Messenger ,Molecular Biology ,Gene ,Genetics ,Lipoprotein lipase ,Mutation ,Splice site mutation ,Base Sequence ,Macrophages ,Intron ,DNA ,Cell Biology ,Blotting, Northern ,medicine.disease ,Molecular biology ,Lipoprotein Lipase ,RNA splicing ,Metabolism, Inborn Errors - Abstract
A donor splice site mutation was found in the lipoprotein lipase (LPL) gene of a patient with familial LPL deficiency. The mutation, a G----A substitution, occurred at the first nucleotide of intron 2. Northern blot analysis of total RNA from the patient showed strikingly low levels of LPL-specific mRNAs. Using the polymerase chain reaction, the LPL mRNA splicing was analyzed in detail. The results demonstrated that no normal splicing occurred at the authentic splice site; rather a cryptic splice site 18 bases upstream from the mutation site was preferentially utilized. Although the resulting alteration in mRNA was a minute in-frame 18-base deletion, the amount of the abnormal transcript was only 1/12 that of the normal. In addition to this major cryptic splice site, we also identified multiple minor sites which were utilized at extremely lower efficiencies. Unexpectedly, one of these minor sites was also used as an alternative splice site in the normal subject at a comparably low efficiency. The sequences of these minor cryptic sites possessed many of the characteristics common to those of other normal splice sites, indicating that even such minor sites should have also been selected according to the general rules for splice site selection. These results demonstrate that upon mutation, a broad spectrum of cryptic splice sites is activated in vivo at the sites' respective efficiencies.
- Published
- 1991
- Full Text
- View/download PDF
42. Hypoxia induces endothelial cell synthesis of membrane-associated proteins
- Author
-
David M. Stern, Matthias Clauss, Revati Shreeniwas, Satoshi Ogawa, S Koga, Caesar C. Butura, and Keisuke Kuwabara
- Subjects
Endothelium ,In Vitro Techniques ,Biology ,chemistry.chemical_compound ,medicine ,Animals ,Electrophoresis, Gel, Two-Dimensional ,Hypoxia ,Blood Coagulation ,Cells, Cultured ,Multidisciplinary ,Activator (genetics) ,Factor X ,Leupeptin ,Membrane Proteins ,Hydrogen-Ion Concentration ,Hypoxia (medical) ,Molecular biology ,Endothelial stem cell ,medicine.anatomical_structure ,chemistry ,Iodoacetamide ,Sodium azide ,Cattle ,Endothelium, Vascular ,medicine.symptom ,Research Article - Abstract
Hypoxemia is associated with a prothrombotic tendency. In this study we report the purification and partial characterization of an activator of a central coagulation component, factor X, induced in endothelium by exposure to hypoxia (hypoxia-induced factor X activator or Xact). Expression of Xact occurred in a reversible manner when endothelial cell cultures were exposed to hypoxia or sodium azide but not in response to a variety of other alterations in the cellular milieu, such as heat shock or glucose deprivation. The activity of Xact, which was not detected in normoxic endothelial cells, was maximal under acidic conditions, pH 6.0-6.8, which often coexist with hypoxia in an ischemic milieu. By sequential isoelectric focusing and preparative SDS/PAGE of endothelial membrane-rich fractions, Xact was purified approximately 19,000-fold and found to be a single-chain, approximately 100-kDa polypeptide with pI approximately 5.0. Activation of factor X by purified Xact was not affected by blocking antibodies to other coagulation proteins or by phenylmethylsulfonyl fluoride or leupeptin but was prevented by mercury chloride or iodoacetamide. In addition to the induction of Xact, two-dimensional gel analysis of membrane fractions from metabolically labeled hypoxic endothelial cultures revealed two groups of approximately 10 additional spots: (i) a group for which expression was maximal after 24 hr and (ii) a group for which expression continued to increase up to 48 hr. The pattern of hypoxia-mediated modulation of protein expression was distinct from that seen with other cellular stimuli but could be duplicated, in part, by sodium azide. These results indicate that hypoxia elicits a specific biosynthetic response, including the expression of endothelial cell-surface molecules that can alter cellular function and may potentially serve as markers of hypoxemic vessel-wall injury.
- Published
- 1991
- Full Text
- View/download PDF
43. Decidual Activation in Parturition: Examination of Amniotic Fluid for Mediators of the Inflammatory Response
- Author
-
S. Koga, Paul C. MacDonald, and M.Linette Casey
- Subjects
Amniotic fluid ,Gene Expression ,Alpha (ethology) ,Enzyme-Linked Immunosorbent Assay ,Inflammation ,General Biochemistry, Genetics and Molecular Biology ,Andrology ,History and Philosophy of Science ,Pregnancy ,Fetal membrane ,Decidua ,Humans ,Medicine ,RNA, Messenger ,Fetus ,Labor, Obstetric ,Amnion ,business.industry ,General Neuroscience ,Amniotic Fluid ,medicine.anatomical_structure ,embryonic structures ,Female ,Tumor necrosis factor alpha ,medicine.symptom ,business ,Interleukin-1 - Abstract
The accumulation of bioactive agents (characteristic of an inflammatory-type response) in amniotic fluid is common during term and preterm labor, viz., interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha). In addition, prostaglandins, including PGE2, PGF2 alpha, and PGFM, also accumulate in amniotic fluid in some cases of term and preterm labor. From these observations, a number of critical questions arise. Namely, 1) what is the tissue source of origin of these agents?; 2) what are the stimuli that evoke this inflammatory response?; and, 3) are these bioactive agents of inflammation involved in the commencement of labor or else a natural accompaniment of the parturition process? It is reasonable to suspect that the decidua is activated during parturition as the membranes-decidua are exposed after cervical dilation to the vaginal/cervical secretions. Amnion and chorion laeve, in the human, are avascular tissues that produce PGE2 but not PGF2 alpha. Therefore, the accumulation of PGF2 alpha and PGFM in amniotic fluid during labor cannot be attributed to a fetal membrane origin. Moreover, the fetal membranes and decidua do not convert PGE2 to PGF2 alpha. In addition, the fetal membranes do not produce mature, i.e., secreted 17kD IL-1 beta. On the other hand, the decidua does produce PGF2 alpha and PGFM and is stimulated to do so by agents in the vaginal secretions, namely, bacterial endotoxin and IL-1 beta. After the fetal membranes and contiguous decidua are exposed during the time of cervical dilatation, these tissues are acted upon to cause 1) an influx of mononuclear phagocytes into the forebag compartment of the amniotic fluid; 2) to produce PGF2 alpha and PGFM; and 3) to produce cytokines, including IL-1 beta, IL-6, and TNF-alpha. Exposure of the fetal membranes-decidua to bioactive agents in vaginal/cervical secretions will effect an inflammatory response both in vivo and in vitro. We conclude that the accumulation of bioactive agents characteristic of the inflammatory response in amniotic fluid during term and preterm labor is usually an accompaniment of parturition and not its cause.
- Published
- 1991
- Full Text
- View/download PDF
44. Electron beam heating tests of newly-developed C/C composites for application to JT-60U divertor plate
- Author
-
Kiyoshi Fukaya, S. Koga, Masuro Ogawa, Seiichiro Yamazaki, Kobayashi Takeshi, M. Etoh, Hideyuki Takatsu, Masanori Araki, Masami Seki, and Yamamoto Masahiro
- Subjects
Nuclear and High Energy Physics ,Thermal shock ,Materials science ,Divertor ,Carbon fibers ,Nuclear Energy and Engineering ,Heat flux ,Energy absorbing ,visual_art ,Thermal ,Cathode ray ,visual_art.visual_art_medium ,General Materials Science ,Composite material ,Heat load - Abstract
C/C (carbon/carbon fiber) composites with very high thermal conductivities close to or over 300 W/m K at RT, which have been under development for a last few years, show superior thermomechanical characteristics and are promising candidates for plasma-facing components of current and next step devices. Electron beam heating tests were carried out for several grades of newly- developed C/C composites to examine their applicability to divertor plates of JT-60 Upgrade (JT-60U) whose heat load specifications are 20–30 MW/m2 for a duration of 5 s. Four grades of felt-type C/C composites showed superior thermal shock resistance and erosion characteristics under a heat flux of 17–35 MW/m2 with a duration of 3–10 s. No macro damage or failure was observed under the conditions tested. Erosion increased gradually with an increase of the absorbed energy, and still remained at a modest level under the absorbed energy of 250 MJ/m2, which was sufficiently higher than the heat load specifications for JT-60U divertor plate.
- Published
- 1991
- Full Text
- View/download PDF
45. Contents, Vol. 47, Supplement 1, 1991
- Author
-
M. Ziegler, Y. Aso, H.J. Rollema, H. Noto, E.A. Tanagho, G. Kimura, A. C. Von Eschenbach, K. Sugaya, S. Komine, M. Tojo, S. Baba, J. Muraki, A. Kondo, H. Hisazumi, H. Tanaka, S. Kubota, L.M. Rainwater, M. Mizunaga, Y. Kawata, M. Takanami, N. Deguchi, R.D. Williams, K. Nagashima, S. Kaneko, M. Satoh, Y. Saito, Y. Hirao, T. Terada, Y. Terashima, S. Jitsukawa, K. Kato, R. Suzuki, M. Akimoto, S. Wada, S. Yachiku, T. Hattori, Z. Masaki, O. Nishizawa, T. Ogawa, T. Ohkawa, T. Shinka, H. Kanetake, A.E.J.L. Kramer, V. Moll, S. Koga, W.F. Whitmore, H. Tazaki, J. Shimazaki, M. Kyo, J. Kumazawa, S. Ikemoto, E. Okajima, T. Kubo, M. Tachibana, T. Kase, N. Miyanaga, K. Kuwashima, T. Yagishita, K. Taniguchi, H. Matsuki, M. Hayakawa, K. Fujimoto, U. Jonas, K. Koiso, T. Yamanishi, C.S. Grant, G. Mast, A. Horii, Y. Nishio, M. Gotoh, Y. Watabe, R. Noguchi, H. Yamashita, T. Kishimoto, J.R. Roppolo, N. Nakayama, K. Kumasaka, S. Ozono, G.M. Farrow, S. Samma, T. Tajima, K. Marumo, I.J. Fidler, T. Uchibayashi, H. Yoshida, J.A. van Heerden, K. Yasuda, M. Kamízuru, M. Ueno, Y. Uekado, R. Yasumoto, Y. Kondo, S. Tsuchida, E. Becht, M. Harada, S. Yamashita, S. Satoh, M. Shirai, A. Hirano, R.A. Janknegt, T. Nishimura, S. Kanoh, K. Koyama, K. Yoshida, H. Ishikawa, R. van Mastrigt, Y. Koyama, Y. Kakehi, O. Yoshida, I. Kaneko, M.M. Lieber, M. Asakawa, Y. Fukui, T. Hatano, M. Matsushima, M. Hata, Y. Hosaka, K. Koshida, Y. Taki, A. Iwai, M. Miyata, M. Nishikido, C. Fujiyama, W.C. de Groat, S. Kawamura, A. Osawa, Y. Sawamura, M. Saito, N. Murayama, K. Miyake, S. Naito, R.M. Levin, W. Sakamoto, A.J. Wein, and M. Maekawa
- Subjects
Traditional medicine ,business.industry ,Urology ,Medicine ,business - Published
- 1991
- Full Text
- View/download PDF
46. Oxidation of Thymidine by Peroxomono- and Peroxodisulfate Ions
- Author
-
S. Koga and Toshio Itahara
- Subjects
Deoxyribonucleoside ,chemistry.chemical_compound ,chemistry ,Sodium peroxodisulfate ,heterocyclic compounds ,General Chemistry ,Potassium peroxymonosulfate ,Thymidine ,Desoxyribonucleoside ,Nuclear chemistry ,Ion - Abstract
Oxidation of thymidine by KHSO5 gave thymidine glycols, while a similar treatment with Na2S2O8 gave 5-hydroxymethyl-2′-deoxyuridine.
- Published
- 1991
- Full Text
- View/download PDF
47. Torque analysis of Co-Cr films prepared under different Ar pressures
- Author
-
I. Koike, T. Yamaguchi, and S. Koga
- Subjects
Argon ,Materials science ,Condensed matter physics ,Analytical chemistry ,chemistry.chemical_element ,Coercivity ,Magnetic hysteresis ,Electronic, Optical and Magnetic Materials ,Magnetization ,Magnetic anisotropy ,chemistry ,Torr ,Electrical and Electronic Engineering ,Thin film ,Cobalt - Abstract
This paper describes the results of torque analysis on the Co-Cr 17-18 at.% sputtered films prepared with the controlled Ar gas pressure (P/sub Ar/) at 4-70 mTorr. At lower P/sub Ar/ (P/sub Ar/ 20 mTorr which indicates the occurrence of incoherent magnetization rotation.
- Published
- 1999
- Full Text
- View/download PDF
48. [Minimally invasive technique for harvesting a saphenous vein via one small incision]
- Author
-
M, Sato, E, Suenaga, S, Koga, and S, Matsuyama
- Subjects
Dermatologic Surgical Procedures ,Tissue and Organ Harvesting ,Humans ,Minimally Invasive Surgical Procedures ,Saphenous Vein - Abstract
We report a minimally invasive technique for harvesting a saphenous vein graft (SVG) via 1 small skin incision. The expected advantages of this technique are better cosmetic results and fewer wound complications than the conventional open technique or the bridging technique. The SVG, 10-15 cm in length, can be harvested by about 3 cm-long single small skin incision. SaphLITE Retractor System (Genzyme Srugical Products, Cambridge), SLS Hematostatic Clip System (Vitalitec International, Plymouth), and curved scissors were necessary instruments for this technique. It is feasible for cases that require a shorter length of SVG.
- Published
- 2007
49. Development of a voxel phantom of Japanese adult male in upright posture
- Author
-
Y. Emoto, Hiroshi Noguchi, Kimiaki Saito, Kaoru Sato, S. Koga, and Akira Endo
- Subjects
Male ,Supine position ,Adult male ,Posture ,computer.software_genre ,Radiation Dosage ,Models, Biological ,Sensitivity and Specificity ,Imaging phantom ,Japan ,Species Specificity ,Voxel ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Computer Simulation ,Tissue Distribution ,Tissue distribution ,Radiometry ,Radiation ,Radiological and Ultrasound Technology ,business.industry ,Phantoms, Imaging ,Public Health, Environmental and Occupational Health ,General Medicine ,Anatomy ,medicine.anatomical_structure ,Organ Specificity ,Abdomen ,Biological Assay ,business ,computer ,Target organ ,Relative Biological Effectiveness - Abstract
A Japanese voxel phantom in upright posture, JM2, has been developed on the basis of CT images of a healthy Japanese adult male. Body characteristics of JM2 were compared with those of the supine voxel phantom, JM, previously developed using CT images of the same person. Differences were found in the shapes of the spine and lower abdomen and the locations of several organs such as kidneys, liver and stomach between the two phantoms. Specific absorbed fractions (SAFs) for 24 target and 11 sources organs were calculated for monoenergetic photon ranging from 0.01 to 4 MeV. It was found that the SAFs for the kidneys as source organ and the lower large intestine wall as target organ in JM2 were significantly higher than those in JM for all photon energies. The differences of the SAFs between the two phantoms were attributed to the differences in the organ distance and organ geometry depending on the posture.
- Published
- 2007
50. 802 Medium-term result of helical tomotherapy for 1000 cases non-metastatic prostate cancer at single institution
- Author
-
F. Tsukuda, N. Sakamoto, Y. Hama, and S. Koga
- Subjects
Oncology ,medicine.medical_specialty ,business.industry ,Urology ,medicine.medical_treatment ,medicine.disease ,Tomotherapy ,Medium term ,Prostate cancer ,Internal medicine ,medicine ,Non metastatic ,Single institution ,business - Published
- 2015
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.