• Journal of Preventive Medicine and Public Health
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• v.38 no.4
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• pp.425-430
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• 2005

Objectives : To investigate the prevalence of Clonorchis Sinensis infestation and to determine the associated risk factors among a population in a part of the rural area of Gyeongsangnam-do, Korea, which is an area known to have a high mortality from liver cancer and a high infection of C. sinensis. Methods : The study populat ion consisted of those people who have lived in rural areas and who were over 40 years old. This study was performed in 5 areas during the period from 1999 to 200 3. Informed consents were obtained from the 2,381 study participants, and these people were interviewed about their life style habits with using the structured questionnaire that was administered by trained staff members. The subjects underwent blood sampling and their stool specimens were examined by using the Formalin-ether sedimentation technique. Results : Among the study subjects (N=2,381), the positivity for C. sinensis in the stool was 34.4% (95% CI=36.3-42.5); it was 39.4% (95% CI=36.3-42.5) in the males and 30.9% (95% CI=28.5-33.3) in the females . The positivity for C. sinensis was associated with current alcohol drinking (odds ratio=1.8, 95% CI: 1.5-2.1) and raw fish consumption (odds ratio 1.2, 95% CI: 0.9-1.6). Conclusion : The present study confirmed the high prevalence of C. sinensis in the study subjects. It is necessary to establish consistent medical management and education programs for the treatment and prevention of C. sinensis infestation in the rural inhabitants of Korea.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.565-569
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• 2016

Recently, a use of linear accelerator with a multi-leaf collimator(MLC) for radiation therapy is increasing. The importance of quality assurance (QA) for the linear accelerator is emphasized as the side effects of the inaccurate delivery of the radiation beam has been increased according to the high dose irradiation technique. In this study, The $HgI_2$ and $PbI_2$ photoconductor layer samples of $400{\mu}m$ thickness were fabricated using sedimentation method among particle-in-binder technology. From the fabricated samples, the electrical properties(dark current, output current, response properties and linearity) were investigated. From the experimental results, $HgI_2$ has good charge signal generation and linearity. Finally, from the signal response results about various thickness of $HgI_2$ sensor, the signal creation efficiency of $400{\mu}m$ thickness of $HgI_2$ sensor has the highest value and the excellent reproducibility below ${\pm}2.5%$.

• Parasites, Hosts and Diseases
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• v.26 no.4
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• pp.275-284
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• 1988

This study was performed to observe the present status of intestinal parasitic infections in a remote island, Yondo, located in southern part of Jeonranam-do (Province) , Korea. In February and May, 1988, total 1,011 individual stool samples were collected and examined for intestinal helminths and protozoa using formalin-ether centrifugal sedimentation technique. The results are summarized as follows: 1. Of 1,011 inhabitants examined, 398(39.4%) were positive for intestinal parasites. Helminth positives were 372(36.8%) , and protozoan cyst positives were 56(5.5%) . 2. Ten species of parasites were found. Trichuris trichiura revealed the highest infection rate of 27.5%, Ascaris lumbricoides 17.4%, Taenia sp. 5.8%, Entamoeba coli 3.3%, Ciardia Zamblia 1.5%, Endelimax nasa 0.8%, Hymenolepis nana 0.4%, Hookworm 0.2%, Trichostrongylus orientalis 0,2%, and Entamoeba histolytica 0.2%, respectively. 3. The female group showed higher positive rate(44.0%) than males (34.7%). Also, higher positive rates were observed among adults as compared with the group younger than 10 years old. 4. Average value of E.P.G. was 1,876(range 200∼17,800) in A. lumbricoides positives, and 327 (range 200∼1,600) in T. trichiura positive cases. 5. In helminth egg Positive cases, single in(traction was 63.4%, double infection 34.7%, and triple infection 1.9%, respectively. Among protozoan cyst positives, single infection was 94.6%, and double infection was 5.4%. The present study revealed that the prevalence of intestinal parasites among inhabitants in Yondo island is still so high that special control measures should be performed.

• Analytical Science and Technology
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• v.13 no.4
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• pp.403-411
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• 2000

This study described a method of thermoluminescence dating of pottery shards using subtraction method. TL measurement was achieved using two different types of samples prepared by quartz inclusion method and fine-grain technique. Fine grains (size range: $5-10{\mu}m$) were separated by suspending grounded pottery samples into acetone solution and sedimentation quantitatively. In quartz inclusion method quartz grains in the size range of 90 to $125{\mu}m$ diameter were obtained by extracting the quartz crystals embed in the pottery shards and etching them with 1.0 M HF solutions. The archaeological dose of both the quartz and fine grains was determined from the dose calibration curves obtained from sequential irradiation of $^{137}Cs$ gamma and $^{241}Am$ alpha source to the samples and TL measurement of natural samples, in which the alpha dose of 4.60 Gy for the Packjae pottery was obtained using subtraction method. Annual alpha dose rates ($3.05{\pm}0.11$ mGy/yr.) were determined by the analysis of U, Th contents in the pottery shards and evaluation of the values with Bell's equation. Dividing the alpha dose accumulated in the pottery shards by the annual alpha dose rate, we found age of approximately $1508{\pm}80$ years B.P. (AD. ca. 492 yr.) for the Packjae pottery. It matches well with the archeological age estimate (middle of 5th century) within 10 percent uncertainty and thereby conforms the age of the pottery sample.

• Parasites, Hosts and Diseases
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• v.36 no.3
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• pp.155-162
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• 1998

Two endemic foci of heterophyid infections were discovered in coastal villages of Puan-gun. Chollabuk-do, and Sachon-gun. Kyongsangnam-do, Korea. Fecal examina- tions were performed on 153 inhabitants of Puan-gun and 138 of Sachon-gun, using cellophane thick smear and formalin-ether sedimentation technique. The helminth egg and/or protozoan cyst positive rate was 21.5% (33/153) in Puan-gun and 39.1% (54/138) in Sachon-gun. In Puan-fun, the egg Positive rate of heterophyids was the highest, 17.6%, and that of other parasites was 0.7-2.6% by parasite species. In Sachon-gun, that of heterophyids wa's 18.8%, followed by Clonorchis sinensis (12.3%). and other parasites (0.7-5.OBEI . Twenth-two (Puan-gun) and six (Sachon-gun) heterophyid egg Positive cases were treated loth praziquantel, and adult flukes were collected from their diarrheic stools. A total of 3,284 adult flukes of Heterophyes nocens was collected from all of the 22 patients treated in Puan-gun (3-778 individually) , and other trematodes were also collected from 2- 15 patients; Ftgidiopsis sumac, Stellcntchcsmus JcEcctus, Metogoninus Wokogaupci, M. miyntci, Stictodora Juscnta, Heterophwopsis continua, Acnnthopcrwphium kurognmo, and GWmnophaELoines seoi. In Sachon-gun, M. yokognwci (3,007 specimens), H. nocens (120), aud S. falcatus (46) were collected from 5 of 6 treated patients, and H. continuo and 5. tan each from one patient. The present study revealed that heterophyid flukes, especially If. nocens and M. Wokofowai, are prevalent in the southern and western coastal areas of Korea where fresh and/or brackish water fishes are popularly eaten raw.

• Resources Recycling
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• v.2 no.2
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• pp.27-38
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• 1993

In this study, we investigated the grinding and sedimentation(elutriation) process of the dusts for the effective separation of high purity iron and iron oxides. For characterization of the dust, particle size distribution and chemical composition, were examined. The results obtained in this study may be summarized as follows : 1. The converter CF(clarifier) dust of the Pohang 1st, 2nd steel making factory and EC(Evaporation Cooler), EP(Eltrostatic precititator) dust of the Kwangyang 2nd steel making factory are composed $\alpha$-Fe(21~50%), FeO(wustite)$Fe_3$$O_4$(magnetite), $Fe_2$$O_3$, CaO, $Al_2$$O_3$, $SiO_2$, and etc. 2. Pure iron has ductile characteristic in nature, particle size of the pure iron increase by increasing the grinding time. On the other hand, it is conformed that bo고 particles of hematite and magnetite become less than 325 mesh after 10 minutes grinding. 3. By applying the elutriation technique for the EC dust of the Kwangyang 2nd steel making factory, the iron powder of high content more than 99.17% of pure Fe was recovered with 37.8% yield at grinding time for 40 minutes. 4. By applying the elutriation technique for the CF dust of the Pohang 2nd steel making factory, the iron powder of high content more than 98.38% of pure Fe was recovered with 44.42% yield at grinding time for 40 minutes. 5. When magnetic separation was performed using plastic bonding magnet of 70 gauss, more than 98% Fe grade of iron powder was recovered in the size range +65 -200 mesh but the recovery of it was low.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.278-286
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• 2006

Purpose : Although suprapubic bladder aspiration(SBA) is the most reliable technique for identifying bacteriuria in young infant, no report has been published about the clinical manifestations of urinary tract infection(UTI) diagnosed by aspirated urine in Korea. This study was performed to examine clinical manifestations and related factors of UTI confirmed by a positive urine culture obtained by SBA in young infants. Methods : We reviewed medical records of 159 infants younger than six months of age, who had been admitted for UTI to Korea University Ansan Hospital from January 2002 to June 2005. Results : The male:female ratio was 5.1 : 1. The most common pathogen in urine culture was Escherichia coli(92.5 percent). Most of the gram-negative pathogens had high sensitivity to amikacin, or third generation cephalosporins and had low sensitivity to ampicillin, trimethoprim-sulfamethoxazole, or gentamicin. Hydronephrosis and vesicoureteral reflux(VUR) were present in 32.7 percent and 27.7 percent respectively. Renal cortical defects observed on DMSA scans were detected in 37.1 percent. Prolonged fever duration and hospital day, high erythrocyte sedimentation rate(ESR) and C-reactive protein(CRP) levels, hydronephrosis and VUR were related to the renal cortical defects(P<0.05). Rates of UTI-associated bacteremia and aseptic meningitis were 8.3 percent and 6.6 percent. Conclusion : Early differential diagnosis is very important in infants younger than 6 months of age with UTI because the clinical findings are non-specific and UTI-associated bacteremia and aseptic meningitis are concomitantly found. Because prolonged fever and higher ESR and CRP levels are risk factors of the renal cortical defects, radiologic evaluations and nephrologic follow-up were needed in identifying the predisposing congenital abnormalities and chronic renal scarring.