• Title/Summary/Keyword: Medical Machinery

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Study on Non-contact Ultrasonic Transducer for Measurement of Fruit Firmness (과실 경도측정을 위한 비접촉 초음파 변환기 연구)

  • Lee, Sang-Dae;Ha, Tae-Hoon;Kim, Ki-Bok;Kim, Man-Soo
    • Journal of Biosystems Engineering
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    • v.35 no.3
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    • pp.189-196
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    • 2010
  • This study was conducted to develop an non-contact ultrasonic transducer for measurement of fruit firmness. The center frequency of non-contact ultrasonic transducer was 500 kHz. As an active element of non-contact ultrasonic transducer, the 1-3 piezoelectric composite material was selected. That material has high piezoelectric properties such as electro-mechanical coupling factor, $k_t$ and piezoelectric voltage constant, $d_{33}$ and also that material has low acoustical impedance which enables to matching the acoustical impedances between piezoelectric material and air. As a front matching material between 1-3 piezoelectric composite material and air, various kinds of paper with different thickness were tested. To control the dead-zone of the fabricated non-contact ultrasonic transducer, the backing material composed of epoxy resin and tungsten powder were made and evaluated. The fabricated non-contact ultrasonic transducer for fruit showed that the cneter frequency, bandwidth and beamwidth were approximately 480 kHz, 30 % and 12 mm, respectively. It was concluded that non-contact measurement of apple firmness would be possible by using the fabricated non-contact ultrasonic transducer.

A Study on Enhancing Managerial Performance of Business Incubators and Developing Differentiation Strategy (비즈니스 인큐베이터의 경영 성과 향상 및 차별화 전략 수립에 대한 연구)

  • SEO, Dayoon;Bae, SungUk;BAE, SungMin
    • Journal of Korean Society for Quality Management
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    • v.45 no.3
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    • pp.463-481
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    • 2017
  • Purpose: This study provide the matching mechanism between startup and business incubator to enhance managerial performance of business incubator. In addition, we propose the differentiation strategy for business incubator based on the needs of startups. Methods: In order to carry out the research, we surveyed 216 startups who already have invested in venture capitals and angel investors and currently residing in business incubator and 30 venture capitals and angel investors. Based on survey results, we develop a business incubator capability table matching startup with business incubator. Results: Satisfaction and importance of the supporting programs varied depending on the startup experience and startup lifecycle. As a result, we recommended a R&D center for machinery/material, bio/medical and electric/electronics startups and individual office for ICT and knowledge service startups. In addition, we suggested a differentiation strategy to BI in university specialized for machinery/material, privately operated BI for electric/electronic, (local)government, R&D center and individual office for knowledge service respectively. Conclusion: In this study, business incubator capability table is applied to match startup with business incubator and it could be applied to evaluate the current status of business incubator. Furthermore, it will help to establish a future strategic direction for business incubator.

A Study on the Hearing Disturbance Based on the Classification of Hazardous Occupation (위험직종(危險職種) 분류(分類)에 따른 난청(難聽)의 고찰(考察))

  • Park, Young-Il
    • The Journal of the Korean life insurance medical association
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    • v.2 no.1
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    • pp.122-127
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    • 1985
  • The basis for determining hearing disturbance adopted by the Life Insurance Industry is the loss of hearing power above 80 db on either or both sides, in accordance with the divide sixth method of audiometric test. Different types of small-to-medium-sized enterprises were chosen for the study of the extent of loss and the power of hearing. The following are the findings: 1. The disturbance percentage found among the types of occupation and different levels of age was found to be higher as the subject's ages increased. 2. The heavier the workload and the noisier the environment, the higher the percentage of disturbance. The average percentage of the subjects turned out to be 24.35%. Those engaged in sawing and wood-work showed 49%. Those engaged in machinery and equipment for transportation accounted for 42.6%. Those engaged in the metal products occupied 39.6%. The disturbance percentage among those engaged in such noisy works as press, pipe and sawing showed 32.52%. 28.46% of those workers with three to four years employment turned out to be disturbed in hearing. Of these, a high percentage of 43.9% showed disturbance in conversation or talk. 3. No hearing loss due to occupation beyond the Life Insurance standard of 80 db was found; therefore, the present status poses no problem. Constant attention, however, is needed.

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Human ChlR1 Stimulates Endonuclease Activity of hFen1 Independently of ATPase Activity

  • Kim, Do-Hyung;Kim, Jeong-Hoon;Park, Byoung Chul;Lee, Do Hee;Cho, Sayeon;Park, Sung Goo
    • Bulletin of the Korean Chemical Society
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    • v.35 no.10
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    • pp.3005-3008
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    • 2014
  • Human ChlR1 protein (hChlR1), a member of the cohesion establishment factor family, plays an important role in the segregation of sister chromatids for maintenance of genome integrity. We previously reported that hChlR1 interacts with hFen1 and stimulates its nuclease activity on the flap-structured DNA substrate covered with RPA. To elucidate the relationship between hChlR1 and Okazaki fragment processing, the effect of hChlR1 on in vitro nuclease activities of hFen1 and hDna2 was examined. Independent of ATPase activity, hChlR1 stimulated endonuclease activity of hFen1 but not that of hDna2. Our findings suggest that the acceleration of Okazaki fragment processing near cohesions may aid in reducing the size of the replication machinery, thereby facilitating its entry through the cohesin ring.

Survey on the Safety Accidents During the Repairing of Agricultural Machinery (농업기계 수리시 안전사고 실태분석)

  • Han, H.G.;Lee, W.Y.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.5 no.1
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    • pp.64-76
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    • 2003
  • This study was conducted in order to find out the basic data and informations for the accidents for repairing of agricultural machines. This study was summarized as fellows : 1. Among the total repair work, the ratio of repair accident was 68.9% and the accident ratio with power tiller, tractor, and combine was 84.8%. The accident occurred frequently in April to May and September to October because of frequent use of machines during this months. The accidents occurred often of ten to eleven and two to three afternoon in a day. 2. The 36.3% of the accident types was farming machines and the 60.4% of the accident occurred in yard of repair shop. The 34.4% of accident was caused by people, 26.2% by machines, 24.9% by environmental factors, and 14.5% by others. 3. In accident damage, human damage was 98.4% and economic damage was 43.6%. There was only 40.2% in having agricultural machinery insurance and 22.5% of research applicant answered that they would not have insurance in the future. 4. The 58.2% of the injured parts occurred in fingers, hands, wrists, or arms and the 74.4% of the damage types were bruise, prick or abrasion. The damaged parts of machinery were belt of power transmission device, chains, sharpened knives, narrow mechanism or cultivating knives for rotary. 5. The average days of medical treatment for casualty was 15.5 days and the average expense of medical treatment per person was 189,200 won. The days of temporary rest and the economic damage per person due to accident were 12.8 days and 469,300 won.

BRCA1 Gene Mutations and Influence of Chemotherapy on Autophagy and Apoptotic Mechanisms in Egyptian Breast Cancer Patients

  • Abdel-Mohsen, Mohamed Ahmed;Ahmed, Omiama Ali;El-Kerm, Yasser Mostafa
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.3
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    • pp.1285-1292
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    • 2016
  • Background: It is well established that mutations in the BRCA1 gene are a major risk factor for breast cancer. Induction of cancer cell death and inhibition of survival are the main principles of cancer therapy. In this context, autophagy may have dual roles in cancer, acting on the one hand as a tumor suppressor and on the other as a mechanism of cell survival that can promote the growth of established tumors. Therefore, understanding the role of autophagy in cancer treatment is critical. Moreover, defects in apoptosis, programmed cell death, may lead to increased resistance to chemotherapy. Purpose: The aim of the present study was to detect BRCA1 gene mutations in order to throw more light on their roles as risk factors for breast cancer in Egypt. Secondly the role of autophagy and apoptosis in determining response to a fluorouracil, doxorubicin, cyclophosphamide (FAC) regimen was investigated. Materials and Methods: Forty-five female breast cancer cases and thirty apparently healthy females were enrolled in the present study. Serum levels of autophagic biomarkers, Beclin 1 and LC3 as well as the serum levels of apoptosis biomarkers Bcl-2 and Caspase-3 were measured before and after chemotherapy. Results: BRCA1 mutations were found in 5 (16.7%) and 44 (99.8%) of the controls and cancer patients, the most frequent being 5382insC followed by C61G and 185 delAG. The results revealed that chemotherapy caused elevation in serum concentration levels of the autophagic biomarkers (Beclin 1 and LC3). This elevation was associated with a significant decrease in serum concentration levels of Bcl-2 and significant increase in caspase-3 concentration levels (apoptotic markers). Conclusions: The results of the present study indicate a very high level of BRCA mutations in breast cancer cases in Egypt and point to involvement of autophagic and apoptotic machinery activation in response to FAC chemotherapy.

Alteration of Immunoreactivity for SNARE Proteins in the Rat Hippocampus after Middle Cerebral Artery Occlusion

  • Park, Jung-Sun;Huh, Pil-Woo;Jung, Yeon-Joo;Park, Su-Jin;Lee, Kyung-Eun
    • The Korean Journal of Physiology and Pharmacology
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    • v.8 no.3
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    • pp.141-146
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    • 2004
  • Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) proteins, composed of two presynaptic membrane proteins [synaptosomal-associated protein of 25 kDa (SNAP-25) and syntaxin] and a presynaptic vesicular protein [vesicle-associated membrane protein (VAMP)], serve as a core of exocytotic fusion machinery, which can be affected by ischemia. Synaptic protein in core region, striatum and cortex has been shown to alter after focal ischemia, however, little is known in hippocampus. Hippocampus is remote from ischemic core, but it is one of the most vulnerable regions. Using immunohistochemistry, the present study was undertaken to investigate the alteration of expression of SNAP-25, syntaxin, and VAMP in the hippocampus of rats which were subjected to middle cerebral artery occlusion (MCAO) for 2h and allowed to reperfuse. At 2 weeks of reperfusion, the SNAP-25 and syntaxin immunoreactivity was increased in the stratum oriens of the CA1 and the stratum lucidum of the CA3 in the ipsilateral hippocampus. However, VAMP immunoreactivity didn't show significant change. These results demonstrate that the level of the presynatpic plasma membrane proteins (SNAP-25 and syntaxin) in the rat hippocampus is more sensitively affected by focal ischemia than that of the synaptic vesicle protein (VAMP).

A Study on Metal Concentrations in the Air of Metal Products Manufacturing Industry (금속제품 제조 산업장내 공기중 금속농도에 관한 연구)

  • Kang, Yong Seon;Kim, Se Dong;Ku, Tae Hyeong;Yoon, Hyeong Ryeol;Moon, Deog Hwan;Han, Yong Soo
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.6 no.2
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    • pp.249-264
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    • 1996
  • This study was conducted for the purpose of obtaining the fundamental data on improvement of working environment and contributing to health improvement of workers who dealed with metal by assessing the metal concentration in air of industries located in Chang-Won Industrial Complex. Authors measured the concentration of metals(Al, Cd, Cr, Cu, Mn, Ni, Pb, Sn and Zn) is the air to 25 working processes of 73 industries by flame atomic absorption spectrometry from February to December 1994. Personal air sampler was used for air sampling with mixed cellulose-ester membrane filter. The results were as follows : 1. The geometric means(range) of metal concentration; 1) Al: $0.1505mg/m^3$ ($0.0147-18.6100mg/m^3$) 2) Cd: $0.0077mg/m^3$ ($0.0003-7.0710mg/m^3$) 3) Cr: $0.0163mg/m^3$ ($0.0013-1.1510mg/m^3$) 4) Cu: $0.0097mg/m^3$ ($0.0009-0.4950mg/m^3$) 5) Mn: $0.0412mg/m^3$ ($0.0006-4.7877mg/m^3$) 6) Ni: $0.0088mg/m^3$ ($0.0001-1.0170mg/m^3$) 7) Pb: $0.0152mg/m^3$ ($0.0015-0.4499mg/m^3$) 8) Sn: $0.0486mg/m^3$ ($0.0037-0.1500mg/m^3$) 9) Zn: $0.1911mg/m^3$ ($0.0122-8.2920mg/m^3$) 2. The geometric mean of lead exceeded TWA in assembling process of other general purpose machinery not elsewhere classified products manufacturing industries.

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Measurement of Flow Field Downstream of Polyurethane Artificial Heart Valve with Floating Valve Leaflet (열림판이 지지대에 고정되지 않은 폴리우레탄 인공판막 하류의 유동장 측정)

  • Kim, J.K.;Sung, J.;Chang, J.K.;Min, B.G.;Yoo, J.Y.
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.247-248
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    • 1998
  • The effect of unattached valve leaflet on flow field downstream of a floating and flapping polyurethane heart valve prosthesis was investigated. With a triggering system and a time-delay circuit the instantaneous velocity field downstream of the valve was measured by particle image velocimetry (PIV) in conjunction with the opening posture of a flexible valve leaflet during a cardiac cycle. Reynolds shear stress distribution was calculated from the velocity fields and wall shear stress was directly measured by hot-film anemometry (HFA). The floating motion of the valve leaflet resulted in the reduction of pressure drop and recirculating flow region downstream of the valve.

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Lubrication Modeling of Reciprocating Piston in Piston Pump with High Lateral Load (강한 측력이 작용하는 피스톤 펌프의 왕복동 피스톤 기구 부에서의 윤활모형에 관한 연구)

  • Shin, JungHun;Jung, DongSoo;Kim, KyungWoong
    • Tribology and Lubricants
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    • v.30 no.2
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    • pp.116-123
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    • 2014
  • The objective of this study is to model and simulate the nonlinear lubrication performance of the sliding part between the piston and cylinder wall in a hydrostatic swash-plate-type axial piston pump. A numerical algorithm is developed that facilitates simultaneous calculation of the rotating body motion and fluid film pressure to observe the fluid film geometry and power loss. It is assumed that solid asperity contact, so-called mixed lubrication in this study, invariably occurs in the swash-plate-type axial piston pump, which produces a higher lateral moment on the pistons than other types of hydrostatic machines. Two comparative mixed lubrication models, rigid and elastic, are used to determine the reaction force and sliding friction. The rigid model does not allow any elastic deformation in the partial lubrication area. The patch shapes, reactive forces, and virtual local elastic deformation in the partial lubrication area are obtained in the elastic contact model using a simple Hertz contact theory. The calculation results show that a higher reaction force and friction loss are obtained in the rigid model, indicating that solid deformation is a significant factor on the lubrication characteristics of the reciprocating piston part.