• Journal of Interdisciplinary Genomics
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• v.2 no.1
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• pp.5-9
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• 2020

von Willebrand disease (VWD) is a genetic bleeding disorders caused by a deficiency of von Willebrand factor (VWF). Diagnosis or exclusion of VWD is not an easy task for most clinicians. These difficulties in diagnosis or exclusion of VWD may be due to preanalytic, analytical and postanalytic laboratory issues. Analytical systems to diagnose VWD may produce misleading results because of limitations in their dynamic range of measurement and low sensitivity. However, preanalytical issues such as sample collection, processing, and transportation affect the diagnosis of VWD profoundly. We will review here the common preanlytical issues that may impact the laboratory diagnosis of VWD.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.67-73
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• 2009

The goal of this study was to assess the level of vibration in an walking-type cultivator, and to provide a basic information to manage the vibration exposure for farmers. The latent periods of vibration-induced white finger (VWF) were assessed through analyzing the vibration levels and frequency characteristics. Also, vibration acceleration levels based on the daily vibration exposure duration was suggested. The latent periods of vibration-induced white finger were assessed by ISO 5349 method. The latent periods were 4.5 and 10.1 years at 10% and 50% of farmer group, respectively. Also, under ACGIH (American Conference of Governmental Industrial Hygienists) standard, daily vibration exposure duration at 6.7 m/s2 of vibration acceleration has to be less than 4 hours. Therefore, education that maximum working hours should be less than 4 continuous hours is necessary for the operators of walking-type cultivators.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.644-649
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• 1994

Recent studies reveal that grip forces due to repeated mechanical vasocompressions are most significant for the genesis of vibration-induced which finger syndrome (VWF). Therefore, exerted grip force was regarded as a dependent variable in 2 experiments and the effects of noise and vibrations of different weighted acceleration levels were studied. Neither grip forces nor peripheral blood flow as indicated by finger skin temperature were influenced by noise or vibrations. the cause of VWF is therefore presumed to be a concomitant variable which correlates with weighted accelerations and with grip forces as well. A possible factor is the weight of hand-held vibrating tools.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.1-16
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• 1996

This study was conducted at an automobile assembly line located in Kyonggi-do, Korea from January 16 to February 28, 1995. The purposes of this study were to assess worker exposures to hand-arm vibration and the performance of gloves for reduction of vibration. The exposure to vibration was measured using to the ISO 5349(1986) method. Vibration acceleration and frequency spectra for each tool were determined on-line replicating actual working conditions and analyzed together with exposure time for evaluating individual worker exposure. Eight pneumatic hand tools, 60 workers exposured to hand-arm vibration, and three pairs of gloves were involved in this study. Results are summarized as follows. 1. Dominant frequencies of vibration for all tools(n=8) measured in this study ranged from 250 Hz to 800 Hz. 2. There was no significant correleration between dominant frequencies and free running speed (p>0.05). 3. Total predicted exposure times of using impact, hammer type did not exceed 40 minutes, but metal finish task, using grinder and sander exceeded 40 minutes. Total exposure time affected significantly the frequency-weighted, 4 hr equivalent acceleration. 4. Predicted prevalence and observed exposure period data were compared in workers(n=60), according to ISO 5349. In this results, 23(50.0 %) and 24(48.07 %) persons exceeded the mean latency periods for vibration-induced white finger(VWF) at 10 % (n=46) and 50 % (n=52) standards, respectively. On the basis of ISO equation, mean latent periods for VWF were 3.23, 4.72 years at 10 %, 50 % standards, respectively. 5. Reduction of vibration by gloves was evaluated. Since impact pneumatic tools produced low frequency vibrations, conventional gloves did not provide any protection. Gloves A and C amplify somewhat the signal at frequency below 400 Hz; the attenuation increases progressively by frequency to reach 18 dB ($7.94{\times}10^{-6}m/s^2$) at 1,000 Hz, slightly worsening Glove B did not provide any protection and made the situation slightly worse. However, since they make the hands warm, the occurrence of vibration-induced white fingers may be reduced.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.75-82
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• 1997

기술의 발달로 인하여 인간이 사용하는 많은 공구들은 전동화되어 사용의 간편함과 아울러 작 업성능의 획기적인 변화를 이루었다. 그러나 이는 반대로 누적외상병이나 VWF(Viberation induced Whiter Finger)와 같은 새로운 문제점과 함께 중량의 증가로 인체에 더 많은 부하를 안겨 주는 부작용도 초래하고 있다. 현대의 많은 수공구들은 그 중량과 반발력을 지탱하기 위하여 대 부분 양손으로 작동하도록 설계되어 있느며, 제품의 성능의 향상에만 그 초점이 맞추어져 왔고 사용자의 안전과 편이성은 상대적으로 무시되어 왔다. 이에 본 연구에서는 이러한 양손공구의 인 간공학적 설계를 위한 체계적인 접근방식을 제시함으로써 산업디자인에 활용됨과 함께 유사한 제 품의 디자인에도 응용될 수 있는 바탕을 마련하고자 한다.

• Proceedings of the Korean Society of Veterinary Clinics Conference
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• 2006.05a
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• pp.170-170
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• 2006

• Journal of The Korean Astronomical Society
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• v.34 no.4
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• pp.321-323
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• 2001

Compressible, magnetohydrodynamic (MHD) turbulence in two dimension is studied through high-resolution, numerical simulations with the isothermal equation of state. First, hydrodynamic turbulence with Mach number $(M)_{rms}\;\~$1 is generated by enforcing a random force. Next, initial, uniform magnetic field of various strengths with Alfvenic Mach number Ma $\gg$ 1 is added. Then, the simulations are followed until MHD turbulence is fully developed. Such turbulence is expected to exist in a variety of astrophysical environments including clusters of galaxies. Although no dissipation is included explicitly in our simulations, truncation errors produce dissipation which induces numerical resistivity. It mimics a hyper-resistivity in our second-order accurate code. After saturation, the resulting flows are categorized as SF (strong field), WF (weak field), and VWF (very weak field) classes respectively, depending on the average magnetic field strength described with Alfvenic Mach number, $(Ma)_{rms}{\ge}1$, $(Ma)_{rms}{\~}1$, and $(Ma)_{rms}{\gg}1$. The characteristics of each class are discussed.

• Journal of Embryo Transfer
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• v.32 no.3
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• pp.87-94
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• 2017

Tissue engineering (TE) has been developed to create functional organs and tissue by combining 3D matrix and cells in vitro. Vascularization and angiogenesis are utmost important for supply of nutrients and oxygen in tissue engineered organs. The present study was performed to isolate and characterize primary endothelial cells (EC) from aorta of alpha 1, 3-enzyme galactosyltransferase knock out (GalT KO) pig, to minimize immune rejection and analyze body immune system for future xenotransplantation studies. Isolation of primary EC from aorta were performed by incubation with dispase for 8-10 min at $37^{\circ}C$. Primary EC were cultured in EC growth medium on different extra cellular matrix (ECM), either collagen or gelation. Primary EC exhibits morphological characteristics and showed positive expressions of EC specific marker proteins i.e. PECAM1, KDR and VWF despite of their ECM surface; however, on collagen based surface they showed increase in mRNA level analyzed by qPCR. Primary EC cultured on collagen were sorted by flow cytometer using KDR marker and cultured as KDR positive cells and KDR negative cells, respectively. KDR positive cells showed dramatically increased in PECAM1 and VWF level as compared to KDR negative cells. Based on the above results, primary EC derived from GalT KO are successfully isolated and survived continuously in culture without becoming overgrown by fibroblast. Therefore, they can be utilize for xeno organ transfer, tissue engineering, and immune rejection study in future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.52-65
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• 1999

This study was performed to evaluate the hand-arm vibration of the steel processing factory workers. Measurement, evaluation and as sessment were based on the International Standard(ISO 5349). The frequency weighted accelerations of the various hand-held tools and total exposure time were measured to assess the periods for the white finger symptom to occur. As a result, it was found that the air angle grinder and the air baby grinder are more harmful than other hand-held tools. It was also found that using various vibratory tools together is more harmful than using a single tool.

• Childhood Kidney Diseases
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• v.10 no.2
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• pp.109-118
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• 2006

Purpose : HUS usually occurs in children after infection with shiga toxin-producing microorganism(D＋HUS). In contrast, non-postdiarrheal(D-) HUS occurs at any age and has a high rate of relapse and a poor prognosis. The clinical presentation of D-HUS is similar to that of thrombotic thrombocytopenic purpura(TTP). Recently severe deficiencies of ADAMTS13 were reported not only in TTP and D- HUS but also in D+ HUS during their acute phase. The purpose of the study is to evaluate the plasma ADAMTS13 activity in D＋ and D-HUS. Methods : Nineteen children with HUS(D＋ HUS 12 and D- HUS 7) were enrolled. The assays of plasma ADAMTS13 activity were performed during the acute stage in the D＋ HUS and at various stages of relapsing courses in the D- HUS patients by multimer assay, based on electrophoresis. Results : The median plasma activity of ADAMTS13 in D＋ HUS and D- HUS were 80.9%(37.8-132.4%) and 53.9%(1.0-94.1%), respectively, which were not statistically significantly different from control(86.4%, 34.2-112.3%)(P>0.05). One boy with D- HUS had severe deficiency of ADAMTS13(1.0%). His platelet count was normalized temporarily by fresh frozen plasma infusion. Conclusion : We have demonstrated that there is no significant difference of the plasma ADAMTS13 activity between D＋ HUS, D- HUS and control. We detected severe deficiency of ADAMTS13 in one boy who presented with relapsing episodes of D- HUS. ADAMTS13 deficiency should be considered in the subgroup of D- HUS especially with early onset and recurrent courses. Plasma therapy can be beneficial in this subgroup.