• Tunnel and Underground Space
• /
• v.20 no.1
• /
• pp.65-72
• /
• 2010

Crack-controlled blasting method which utilizes notched charge hole has been proposed in order to achieve smooth fracture plane and minimize the excavation damage zone. In this study, the blast models, which have a notched charge hole, were analyzed using dynamic fracture process analysis software to investigate the effect of the geometry of a notched charge hole and decoupling indexes of the charge hole on crack growth control in blasting. As a result, crack extension increased and damage crack decreased with the notch length. Ultimately, stress increment factors and resultant fracture patterns with different notch length and width were analyzed in order to examine the effect factors on the crack growth controlling in rock blasts using a notched charge hole.

• Biomolecules & Therapeutics
• /
• v.23 no.2
• /
• pp.141-148
• /
• 2015

Epithelial mesenchymal transition (EMT) is the first step in metastasis and implicated in the phenotype of cancer stem cells. Therefore, understanding and controlling EMT, are essential to the prevention and cure of metastasis. In the present study, we examined, by Western blot, reverse transcription polymerase chain reaction (RT-PCR), and confocal microscopy, the effects of cardamonin (CDN) on transforming growth factor-${\beta}1$ (TGF-${\beta}1$)-induced EMT of A549 lung adenocarcinoma cell lines. TGF-${\beta}1$ induced expression of N-cadherin and decreased expression of E-cadherin. CDN suppressed N-cadherin expression and restored E-cadherin expression. Further, TGF-${\beta}1$ induced migration and invasion of A549 cancer cells, which was suppressed by CDN. TGF-${\beta}1$ induced c-Jun N-terminal kinase (JNK) activation during EMT, but CDN blocked it. Protein serine/threonine phosphatase 2A (PP2A) expression in A549 cancer cells was reduced by TGF-${\beta}1$ but CDN restored it. The overall data suggested that CDN suppresses TGF-${\beta}1$-induced EMT via PP2A restoration, making it a potential new drug candidate that controls metastasis.

• Journal of Preventive Medicine and Public Health
• /
• v.31 no.3 s.62
• /
• pp.384-394
• /
• 1998

In order to investigate the effect of the urinary excretion of sodium and potassium on the change on blood pressure over 3 years, 668 adolescents aged 13 years living in Kangwha area were investigated in a longitudinal follow-up study. Two measurements were taken on each blood pressure (diastolic, systolic) and the average of the two readings was used in the analysis. Sodium and potassium intake were estimated by the determination of those electrolytes in 24hr urine. The mixed model regression analysis was used to identify the effect of urinary sodium and potassium on the change of blood pressure after controlling for BMI of each age. On simple bivariate analysis no relationship was found between urinary sodium excretion and systolic or diastolic blood pressure among both male and female, however, a significant positive association between urinary potassium excretion and systolic blood pressure among male. The results of mixed regression analysis showed that the body mass index (BMI) were more influential that urinary electrolytes among this study subjects. It suggested that risk factors observed from the adults, may not be identical with that of the growing aged population. After control of the BMI and age, significant association between sodium and diastolic BP among male, and association between potassium and systolic BP among female, were found. In summary, the results indicate that growth has been more influential than dietary factor on blood pressure for growing aged population.

• Journal of Preventive Medicine and Public Health
• /
• v.37 no.2
• /
• pp.141-149
• /
• 2004

Objectives : To evaluate the cost and proportion of complementary and alternative medicines (CAM) in the total healthcare costs among the elderly in the last 6 months of life. Methods : The care-giving families of 301 persons older than 65 years, who died between July 1st and December 31st of 2001, and were also registered in Self-Employed Health Insurance Programs in Seoul, were interviewed. Results : The cost of CAM was 1.09 million Won, which as a proportion of the total healthcare cost was 38.1%. The elderly aged between 65 and 69 year-old, male, living with their spouse, Buddhist and having cancers had higher CAM costs in an ANOVA and simple regression analysis. After controlling of various factors, age was the only significant factor associated with the cost of CAM. The elderly above 80 years old, female, bereaved and Buddhist had higher proportional CAM costs, and the elderly having cancers or cardiovascular diseases had lower proportional CAM costs in an ANOVA and simple regression analysis. After adjusting for various factors, the elderly above 85 years old, female and Buddhist had higher proportional CAM costs, and the elderly having cancers had lower proportional CAM costs. Conclusion : The very old and Buddhist, and/or the ill with no clear diagnosis, may depend more on CAM. Further research will be needed on the meaning and impact of CAM and their costs to public health and the total healthcare system.

• Journal of the Korean Society of School Health
• /
• v.17 no.1
• /
• pp.71-83
• /
• 2004

Purpose: To describe the prevalence, epidemiological characteristics, and related factors of diabetes mellitus in school personnel. Method：5,384 school personnel (2,638 males 2,746 females) received physical examinations at the Seoul School Health Center in 2002. Using the American Diabetes Association criteria, and fasting blood sugar(FBS) was classified as normal at 110>=FBS, borderline 111-125, and the diabetes group 126<=FBS. Related factors of each group were evaluated by gender. Results： In the diabetes group, there were 4.74% males and 0.8% females, and the borderline group was 6.37% males and 2.22% females. The older age group gad a higher distribution in both males and females in the diabetes group. In the diabetes group, the mean and abnormal rate of BMI, systolic hypertension, diastolic hypertension, total cholesterol, GOT, GPT, and GTP were higher than in the normal group. In life style factor, the diabetes group gad a higher distribution of meat eating and smoking more than 20 years than the normal group. The effect of FBS on BMI, BP(blood pressure), total cholesterol, GOT, GPT, and GTP were investigated after controlling for confounding variables. In the borderline and diabetes group, the mean of BMI, BP, total cholesterol, GOT, GPT, and GTP was higher in dose-response effect. In the logistic multiple regression, the related factors of the diabetes group were hypertension and abnormal GTP in males, and abnormal total cholesterol and GTP in females. In the borderline group, the related factors were meat eating, hypertension, and high GOT in males and the older age group, and hypertension, total cholesterol, and abnormal GTP in females. Conclusions: It is possible to manage all related factors of diabetes mellitus except for age. An appropriate program for health promotion is necessary.

• Journal of Sericultural and Entomological Science
• /
• v.29 no.2
• /
• pp.15-23
• /
• 1987

The strain differences in larval walking behavior of 39 silkworm varieties, Bombyy mori, have been investigated. larval walking distance in silkworm varieties were remakably different. The walking distance was the longest in the matured larvae following the newly hatched larvae and in the other larval stage the distance was very short. The means of the walking distance in larval stages were as follows ; newly hatched larvae was 2.58cm, 3rd instar 0.72cm, 5th instar 1.18cm and matured larvae 2.94cm. The length of relative walking distances in each variety was not always in proportion to each larval stage. Therefore, the controlling factor of walking behavior was assumed to be different by the each larval stage. In the newly hatched larvae, 3rd instar and 5th instar larvae, the distribution range of walking distance was very broad in European races, narrow in Chinese races and medium in Japanese races. There was not much differences in the walking distance of mature larvae among European, Chinese and Japanese races.

• Tribology and Lubricants
• /
• v.32 no.2
• /
• pp.44-49
• /
• 2016

Diamond mechanical polishing (DMP) is a crucial process in a sapphire wafering process to improve flatness and achieve the target thickness by using free abrasives. In a DMP process, material removal rate (MRR) is a key factor to reduce process time and cost. Controlling mechanical parameters, such as velocity and pressure, can increase the MRR in a DMP process. However, there are limitations of using high velocities and pressures for achieving a high MRR owing to their side effects. In this paper, we present the lapping characteristics and improvement of MRR by using a fixed abrasive plate through an experimental study. The change in MRR as a function of velocity and pressure follows Preston's equation. The surface roughness of a wafer decreases as the plate velocity and pressure increases. We observe a sharp decrease in MRR over the lapping time at a high velocity and pressure in the velocity and pressure test. An analysis of surface roughness (Rq and Rpk) indicates that wear of abrasives decreases the MRR sharply. In order to investigate the effect of abrasive wear on the MRR, we utilize a cutting fluid and a rough wafer. The cutting fluid delays the wear of abrasives resulting in improvement of MRR drop. The rough wafer maintains the MRR at a stable rate by self-dressing.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.6
• /
• pp.767-777
• /
• 2012

Annular Biofilm Reactor (ABR) equipped with coupons of three different pipe materials (STS 304, PVC, PE) was used to generate drinking water biofilm samples. The level of assimilable organic carbon (AOC) during the sample generation period was $37.3{\mu}g/L$, and this level did not seem to be low enough to limit the formation of biofilm in this study. Terminal-restriction fragment length polymorphism (T-RFLP) analyses determined T-RF profile as early as 3 h of exposure on PVC coupons. Average surface roughness ($R_a$) measured by atomic force microscopic analyses was 125.7 nm for PVC, and this value was higher than for STS (71.6 nm) and PE (74.0 nm). However, biofilm formation was faster on STS (6 h) than on PE (12 h), which indicated that surface roughness might not be the only factor that controlled the initiation of biofilm development. Upon detection of the T-RF peaks, richness (S) and diversity indices such as Shannon (H) and Simpson (1/D) demonstrated a rather slow increase until 48 h followed by rapid increase regardless of the pipe materials. Differences of microbial community structures among the biofilm samples were determined based on the cluster analysis using Jaccard coefficients (Sj). Biofilm communities could be divided into two distinct groups according to the exposure time regardless of the pipe materials. First group contained a young (< 48 h) biofilm samples (10 out of 11) but second group contained a mature (${\geq}$ 48 h) samples (11 out of 14). Results suggested that, due to the complexity of biofilm, the targeting of the first group of cluster was crucial for optimizing the management of drinking water distribution systems and controlling microbial growth.

• Korean Journal of Microbiology
• /
• v.49 no.3
• /
• pp.215-220
• /
• 2013

Against environmental stresses, many bacteria utilize the alternate sigma factor RpoS that induces transcription of the specific set of genes helpful in promoting bacterial survival. Intracellular levels of RpoS are determined mainly by its turnover through proteolysis of ClpXP protease. Delivery of RpoS to ClpXP strictly requires the adaptor protein RssB. The two-component-type response regulator RssB constantly interacts with RpoS, but diverse environmental changes inhibit this interaction through modification of RssB activity, which increases RpoS levels in bacteria. This review discusses and summarizes recent findings on regulatory factors in RssB-RpoS interactions, including IraD, IraM, IraP anti-adaptor proteins of RssB and phosphorylation of N-terminal receiver domain of RssB. New information shows that the coordinated regulation of RssB activity in controlling RpoS turnover confers efficient bacterial defense against stresses.

• Korean Journal of Materials Research
• /
• v.17 no.1
• /
• pp.11-17
• /
• 2007

Turbulent in-situ mixing process is a new material process technology to get dispersed phase in nanometer size by controlling reaction of liquid/solid, liquid/gas, flow ana solidification speed simultaneously. In this study, mixing which is the key technology to this synthesis method was studied by computational fluid dynamics. For the simulation of mixing of liquid metal, static mixers investigated. Two inlets for different liquid metal meet ana merge like 'Y' shape tube having various shapes and radios of curve. The performance of mixer was evaluated with quantitative analysis with coefficient of variance of mass fraction. Also, detailed plots of intersection were presented to understand effect of mixer shape on mixing. The simulations show that the Reynolds number (Re) is the important factor to mixing and dispersion of $TiB_2$ particles. Mixer was designed according to the simulation, and $Cu-TiB_2$ nano composites were evaluated. $TiB_2$ nano particles were uniformly dispersed when Re was 1000, and cluster formation and reduction in volume fraction of $TiB_2$ were found at higher Re.