Photoreception for Photoperiodism and Circadian Rhythms in the Blow Fly

Shiga, Sakiko,Numata, Hideharu Korean Society of Photoscience 2002 Journal of Photosciences Vol.9 No.2

A comparison of the functional components underlying photoperiodism and circadian rhythmicity in the same species is an interesting issue in the context of unravelling clock mechanisms. In the present study, covering or surgical removal of the compound eyes was performed to localize photoreceptors for photoperiodism to control reproductive diapause and for entrainment of circadian locomotor rhythms in the blow fly Protophormia terraenovae. Intact flies showed a long-day photoperiodic response. When the compound eyes were covered by silver paint, diapause incidence increased under diapause-averting conditions of a long-day photoperiod and constant light, as if flies were kept under constant darkness. Covering of a medial region of the head capsule or solvent painting of the compound eyes gave no significant effects. When the compound eyes were removed, flies did not distinguish the photoperiod, whereas removal of antennal lobes or ocelli did not affect the photoperiodism. Intact flies showed a freerunning rhythm under constant darkness. The rhythm entrained to light-dark (LD) cycles with light of high and low intensity. When the compound eyes and ocelli were surgically removed, the rhythm entrained to LD cycles with light of high intensity but freeran under LD cycles with light of low intensity. The results suggest the retinal pathways are involved in photoperiodism and that flies use both retinal and extraretinal pathways for rhythm entrainment. Under dim light-LD cycles, the retinal pathways mainly mediate rhythm entrainment. Retinal photoreceptors seem to be used both for photoperiodism and entrainment of the rhythm.

EFFECT OF OVER-EXPANSION CYCLE IN A SPARK-IGNITION ENGINE USING LATE-CLOSING OF INTAKE VALVE AND ITS THERMODYNAMIC CONSIDERATION OF THE MECHANISM

Shiga, S.,Hirooka, Y.,Miyashita, Y.,Yagi, S.,Machacon, H.T.C.,Karasawa, T.,Nakamura, H. The Korean Society of Automotive Engineers 2001 International journal of automotive technology Vol.2 No.1

This paper presents further investigation into the effect of over-expansion cycle in a spark-ignition engine. On the basis of the results obtained in previous studies, several combinations of late-closing (LC) of intake valve and expansion ratio were tested using a single-cylinder production engine. A large volume of intake capacity was inserted into the intake manifold to simulate multi-cylinder engines. With the large capacity volume, LC can decrease the pumping loss and then increase the mechanical efficiency. Increasing the expansion ratio from 11 to 23.9 with LC application can produce about 13% improvement of thermal efficiency which was suggested to be caused by the increased cycle efficiency. The decrease of compression ratio from 11 to 5.5 gives little effect on the thermal efficiency if the expansion ratio could be kept constant. Thus, the expansion ratio is revealed to be a determining factor for cycle efficiency, while compression ratio is no more important, which suggests the usefulness of controlling the intake charge with intake valve closure timing. These were successfully explained by simple thermodynamic calculation and thus the mechanism could be verified by the estimation.

Mercury Free Flat Discharge Lamps for LCD Backlighting

Shiga, Tomokazu The Korean Institute of IIIuminating and Electrica 2001 조명.전기설비 Vol.15 No.2

LCD는 비발광형 소자이므로 배면광이 필요하다. 현재의 LCD 배면광용 냉음극 형광램프는 전기-광학적 특성을 좋게 하기 위하여 수은방전을 사용한다. 그러나 수은의 이용은 외부 온도에 따라 특성이 변하는 결점과 환경 문제가 있다. 이 결점을 보완하기 위하여 원통방전형, 미세방전형 그리고 평면방전형 등 세가지 방식의 무수은 램프가 개발되어 왔다. 원통 방전형 무수은 램프는 수은 대신 Xe을 사용한다. Xe 방전이 수축되는 것을 막기 위하여 한쪽 전극은 외벽에 코일형태로 감아서 사용한다. 그리고 코일형태의 전극의 권선 간격을 조절하여 균일한 방전을 얻는다. 이 형태는 무수은 냉음극 형광램프의 두배의 광속을 얻을 수가 있다. 미세방전형 무수은 램프는 두 개의 절연체로 절연되 금속 전극사이의 방전공간에 수많은 미세방전을 일으켜 발광시킨다. 이 방식은 대향 방전구조와 면 방전구조의 두가지가 있다. 이 방식은 전극이 유전체로 둘러쌓여 있으므로 수명이 높다. 새로운 평면방전형 무수은 램프를 개발하였다. 이 램프는 두 개의 유리평판 사이에 방전공간을 만들고 한쪽 유리면의 양쪽 가장자리에 두 개의 전극을 설치하여 면방전을 유도한다. 양쪽 유리면에는 삼원색 형광체를 도포하고 Xe을 봉입하여 Xe의 진공자외선으로 형광체를 발광시킨다. 이 램프는 전극이 유전체로 덮혀있어 수명이 길다. 실험결과 기체압력 6.7[kPa], 구동전압 1,130[V]에서 최대휘도 9,200[$cd/m^2$], 광효율 20.4[lm/W]을 었었고, 기체 압력 2.7[kPa] 구동전압 1,120[V]에서 최대효율 34.1[lm/W], 휘도 1,080[$cd/m^2$]을 얻었다. 현재 무수은 램프는 수은 램프에 비해서 광학적 특성이 좋지 못하다. 무수은 램프에서 좋은 광학적 특성을 얻기 위해 가장 중요한 것은 수축이 없이 방전을 확산시키는 것이다. 이를 위해서 램프구조와 구동법을 최적화하는 것이 필요하다. 또한 기체압력을 높임으로서 Xe의 여기복사를 얻을 수 있었다.

Atomization Improvement of a Liquid Jet with Wall Impingement and its Application to a Jet Engine Atomizer

Shiga, Seiichi The Institute for Liquid Atomization and Spray Sys 2006 한국액체미립화학회지 Vol.11 No.3

In the present study, capability of improving the liquid atomization of a high-speed liquid jet by using wall impingement is explored, and its application to a jet engine atomize. is demonstrated. Water is injected from a thin nozzle. The liquid jet impinges on a wall positioned close to the nozzle exit, forming a liquid film. The liquid film velocity and the SMD were measured with PDA and LDSA, respectively. It was shown that the SMD of the droplets was determined by the liquid film velocity and impingement angle, regardless of the injection pressure or impingement wall diameter. When the liquid film velocity was smaller than 300m/s, a smaller SMD was obtained, compared with a simple free jet. This wall impingement technique was applied to a conventional air-blasting nozzle for jet engines. A real-size air-blasting burner was installed in a test rig in which three thin holes were made to accommodate liquid injection toward the intermediate ring, as an impingement wall. The air velocity was varied from 41 to 92m/s, and the liquid injection pressure was varied from 0.5 to 7.5 MPa. Combining wall impinging pressure atomization with gas-blasting produces remarkable improvement in atomization, which is contributed by the droplets produced in the pressure atomization mode. Comparison with the previous formulation for conventional gas-blasting atomization is also made, and the effectiveness of utilizing pressure atomization with wall impingement is shown.

Capability of Pulse-Doped GaAs MESFETs as Active Devices for Satellite Communications

Nobuo Shiga,Shigeru Nakajima,Kenji Otobe,Takeshi Sekiguchi,Nobuhiro Kuwata,Ken-ichiro Matsuzaki,Hideki Hayashi 대한전자공학회 1990 JC-CNSS : Joint Conference on Communications, Netw Vol.3 No.-

Atomization Improvement of a Liquid Jet with Wall Impingement and its Application to a Jet Engine Atomizer

( Seiichi Shiga ) 한국분무공학회 2006 한국액체미립화학회지 Vol.11 No.3

New Mongolian records of two genera, seven species, and two hybrid nothospecies from Khar-Us Lake and its associated wetlands

Takashi shiga,Khurelbaatar Khaliunaa,Shukherdorj Baasanmunkh,Batlai Oyuntsetseg,Shotaro Midorikawa,Hyeok Jae Choi 국립중앙과학관 2020 Journal of Asia-Pacific Biodiversity Vol.13 No.3

During a floristic survey of Khar-Us Lake and its associated wetlands in Khovd Province, we found sevenspecies and two hybrid nothospecies that have not previously been recorded in Mongolia. These taxawere found in seven localities and included Hydrilla verticillata (L.f.) Royle, Najas flexilis (Willd.) Rostk. &W.L.E. Schmidt, N. minor All., and N. tenuissima (A.Braun ex Magnus) Magnus (Hydrocaritaceae);Potamogeton angustifolius J. Presl (Potamogetonaceae); Ceratophyllum platyacanthum Cham. subsp. oryzetorum (Kom.) Les (Ceratophyllaceae); Aldrovanda vesiculosa L. (Droseraceae); Veronica anagalloidesGuss. (Plantaginaceae); and Utricularia japonica Makino (Lentibulariaceae). Two of these genera,Hydrilla Rich. and Aldrovanda L., were also newly recorded from Mongolia. The addition of these taxa tothe present Mongolian flora list brings the numbers of registered taxa and genera to 3,200 and 686,respectively. The morphological characteristics, diagnostic features, and distribution of these taxa inMongolia are described in this report.

Theoretical Study of Heterogeneous Ziegler-Natta Catalysts: A Comparison between TiCl3 Catalysts and MgCl2 Supported Catalysts by Using Paired Interacting Orbitals (PIO) Analysis

Akinobu Shiga 한국고분자학회 2010 Macromolecular Research Vol.18 No.10

Two types of industrial heterogeneous Ziegler-Natta propylene polymerization catalysts, TiCl3 type and MgCl2 supported TiCl4 type, were examined by paired interacting orbitals (PIO) analysis proposed by Fujimoto et al.. The ligand located trans to propylene was found to obstruct the insertion but was essential for the stereospecific insertion of propylene. The ligand located trans to the alkyl group of the active site was found to be necessary for activating the alkyl-Ti bond. The regioselectivity and stereoselectivity of the iso-specific polymerization site on the heterogeneous Ziegler-Natta catalyst system were confirmed. The polymerization activity of MgCl2 supported TiCl4catalyst was larger than that of the TiCl3 catalyst.

Freeze-Dried Human Platelet-Rich Plasma Retains Activation and Growth Factor Expression after an Eight-Week Preservation Period

Yasuhiro Shiga,Go Kubota,Sumihisa Orita,Kazuhide Inage,Hiroto Kamoda,Masaomi Yamashita,Toru Iseki,Michihiro Ito,Kazuyo Yamauchi,Yawara Eguchi,Takeshi Sainoh,Jun Sato,Kazuki Fujimoto,Koki Abe,Hirohito 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.3

Study Design: Controlled laboratory study. Purpose: This study aimed to evaluate the efficacy of platelet-rich plasma (PRP) stored at room temperature (RT), frozen, or after freeze-drying. Overview of Literature: PRP enriches tissue repair and regeneration, and is a novel treatment option for musculoskeletal pathologies. However, whether biological activity is preserved during PRP storage remains uncertain. Methods: PRP was prepared from blood of 12 healthy human volunteers (200 mL/person) and stored using three methods: PRP was stored at RT with shaking, PRP was frozen and stored at –80°C, or PRP was freeze-dried and stored at RT. Platelet counts and growth factor content were examined immediately after preparation, as well as 2, 4, and 8 weeks after storage. Platelet activation rate was quantified by flow cytometry. Results: Platelet counts were impossible to determine in many RT samples after 2 weeks, but they remained at constant levels in frozen and freeze-dried samples, even after 8 weeks of storage. Flow cytometry showed approximately 80% activation of the platelets regardless of storage conditions. Almost no growth factors were detected in the RT samples after 8 weeks, while low but significant expression was detected in the frozen and freeze-dried PRP. Over time, the mean relative concentrations of various growth factors decreased significantly or disappeared in the RT group. In the frozen group, levels were maintained for 4 weeks, but decreased significantly by 8 weeks (p <0.05). The freeze-dried group maintained baseline levels of growth factors for the entire 8-week duration. Conclusions: Freeze-drying enables PRP storage while maintaining bioactivity and efficacy for extended periods.

Actual distribution and present status of a threatened aquatic plant, Sagittaria aginashi (Alismataceae), in Korea

Takashi shiga,Kazumasa Tsubota,최혁재 한국식물분류학회 2017 식물 분류학회지 Vol.47 No.3

We evaluated the actual distribution, present status, and number of remnant individuals of Korean Sagittaria aginashi (Alismataceae) based on herbarium specimens and field surveys. We also reidentified Korean S. aginashi by analyzing sequences of the internal transcribed spacer (ITS) region. We found nine specimens of S. aginashi in herbaria from four localities housed at the Osaka Museum of Natural History (OSA) and at the Korea National Herbarium (KH). During our field research, we could not confirm the current statuses of two collection localities (Taereung and Ansan-si), though this was not the case for Ulsan-si. In addition, we found two new localities in Ulsan-si and Yangsan-si. These three remnant populations are distributed in wetlands in mountainous areas (elev. 480–740 m). With regard to the number of flowering and immature individuals in the three localities, there were <50 and <2,000, respectively, in total. ITS sequences demonstrated that the sequences of Korean and Japanese S. aginashi are uniform and distinct from other Sagittaria species. These results indicate that S. aginashi is a rare and threatened species in Korea. It should be listed as an endangered species on the Korean Red List and requires urgent protection by conservation programs, including the extensive surveys of other possible natural habitats.