• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1677-1685
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• 2014

Short discrete fibers compounded with concrete can enhance the tensile resistance and ductility of concrete. Recently, the effectiveness of the reinforcement has increased according to the increasing length of steel fiber. However, the lengthening of steel fiber requires reducing the ratio of the fiber content to remain the workability and quality of concrete. Thus, the present study evaluated the flexural performance of fiber reinforced concrete with less than l.0% fiber volume ratios of steel fiber, 30mm and 60mm long, and polypropylene fiber, being evaluated as a good reinforcing material with chemical stability, long-term durability, and cost effectiveness. Concrete with more than 0.25% steel and 0.5% polypropylene fibers improved the brittle failure of concrete after reaching cracking strength. Concrete reinforced with polypropylene exhibited deflection-softening behavior, but that with more than 0.5% polypropylene delayed stress reduction and recovered flexural strength by 60 to 80% after cracking strength. In conclusion, concrete reinforced with more than 0.75% polypropylene could improve structural flexural performance. In particular, energy absorption capacity of reinforced concrete with 1.0% polypropylene fiber was similar to that with 0.5% and 0.7% steel fibers.

• Korean Journal of Social Welfare
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• v.59 no.1
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• pp.199-221
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• 2007

This study examines the conditions and causes of income inequality and seeks assignments for mitigating income inequality. An analysis of the conditions and causes of income inequality is summarized as follows. First, income inequality, which rapidly increased after the economic crisis, increased and reduced repeatedly during 1999-2004, and remained a level in 2005 as high as that of the year directly after the economic crisis. Second, an analysis of the causes of income inequality by utilizing the long-term data(1985-2004) shows that unemployment rate, nonstandard employment rate, and the rising rate of land prices positively affect income inequality. Third, an analysis of the causes of income inequality by utilizing the data before and after the economic crisis(1995-2004) demonstrates that unemployment rate, nonstandard employment rate, and the workers' income ratio between large enterprises and small enterprises positively affect income inequality. Fourth, the rising rate of land prices which significantly affects income inequality in the data of 1985-2004 does not affect income equality in the data of 1995-2004, and the workers' income ratio between large enterprises and small enterprises which does not affect income inequality in the data of 1985-2004 significantly affect income equality in the data of 1995-2004. These results suggest several implications for mitigating income inequality. First, alternative plans to reduce unemployment rate must be prepared. Second, policies to reduce nonstandard employment rate should be established. Third, programs to stabilize or lower the land prices must be deliberated. Fourth, a master-plan to support small to medium enterprises must be carried out in order to reduce the wage differentials between large enterprises and small to medium enterprises.

• Journal of Chest Surgery
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• v.39 no.3 s.260
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• pp.214-219
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• 2006

Background: Perforation of esophagus is relatively uncommon. but it is associated with high morbidity and mortality. Treatment and outcome are largely determined by the time of presentation. We performed a retrospective review of patients with esophageal perforation to assess the outcome of current management techniques. Material and Method: A retrospective chart review was performed on all patients treated for perforation of esophagus from March 1990 to March 2005. There were 28 patients (22 men and 6 women: mean age 51 years, range 17 to 82 years) The causes of the perforations were as follows: foreign body retention (9 patients), trauma (7 patients), spontaneous rupture (7 patients), and iatrogenic (5 pati-ients). 18 patients were presented within 24 hours and 10 patients were presented after 24 hours., Esophageal repair was performed in 21 ($75\%$) of them, 4 patients were treated with esophagectomy, 3 patients were treated with feeding gastrostomy and drainage. Result: Hospital mortality was $18\%$ and iatrogenic was increase the mortality rate (p < 0.05). Site of perforation, time from perforation, and treatment method had no influence on mortality. Postoprative leaks occurred in 4 patients after primary repair and were treated conservatively. Conclusion: Esophageal perforation remains a devastating event which is difficult to diagnose and manage. Primary repair can be performed in most patients with esophageal perforation regardless of time to presentation with a low mortality. Accurate diagnosis and early treatment are essential to the successful management of patients.

• Journal of the Korean Society of Radiology
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• v.81 no.2
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• pp.409-417
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• 2020

Purpose To evaluate the safety and efficacy of the percutaneous manual aspiration thrombectomy technique to treat thrombotic occlusion of native arteriovenous fistulas. Materials and Methods A retrospective review of 20 patients who underwent percutaneous manual aspiration thrombectomy for native thrombotic arteriovenous fistula occlusion from March 2012 to December 2017 was performed. We evaluated technical and clinical success rates and complications. The primary and secondary patency rates were calculated using the Kaplan-Meier analysis. Results Percutaneous manual aspiration thrombectomy was performed in 20 patients (n = 20) with concomitant balloon angioplasty. The overall technical and clinical success rates were both 85% (n = 17). The native arteriovenous fistulas, based on their site, were the left radiocephalic (n = 13), left brachiocephalic (n = 4), and right radiocephalic (n = 3) fistulas. An underlying stenosis was detected in the juxta-anastomotic venous site (n = 16), outflow draining vein (n = 12), and central vein (n = 4). The primary and secondary patency rates at 1, 3, 6, and 12 months were 100%, 70.6%, 70.6%, and 56.5% and 100%, 94.1%, 94.1%, and 86.9%, respectively. There were no complications associated with procedure. Conclusion Percutaneous manual aspiration thrombectomy is a safe and effective method to treat thrombotic native arteriovenous fistula occlusion.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.4
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• pp.217-224
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• 2021

Purpose: The purpose of this study was to evaluate the porosity of resin modified glass ionomer (RMGI) by different mixing methods. Materials and Methods: Five specimens were prepared for each groups according to capsules and mixing methods. Two RMGI capsule and two mixing machines were used for this study. One resin-modified glass ionomer cement is Fuji II LC (F2LC) and the other is Photac Fil Quick Aplicap (PFQ). For Mixing of RMGI capsule, Rotomix using rotating motion and CM-II using shaking motion were used. After measuring height, radius and mass of specimens, Density was calculated. And porosity was measured using micro-computed tomography (micro-CT). All data were statistically analyzed using T-test, two-way ANOVA to compare between groups at 95% significance level to evaluate the affect of capsule and mixing method on the porosity. Results: The porosity was observed in all specimens generally. And there is significant differece between porosities according to RMGI capsule and Mixing method. The porosity of PFQ was lower than that of F2LC and the porosity of Rotomix was lower than that of CM-II. Conclusion: There was a difference of porosity according to kind of capsules and mixing methods. When using same capsule, less porosity was observed on PFQ than F2LC. When using same mixing mehod, less porosity was observed on Rotomix than CM-II. Using mixing machine of same coporation as that of RMGI capsule did not lead to lower porosity. Therefore, Selecting optimal mixing machine is important.

• Parasites, Hosts and Diseases
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• v.21 no.1
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• pp.58-74
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• 1983

요꼬가와흡충을 수감염시켰을 태의 탕병증을 관찰하고자 은어로부터 분리한 피예유충을 모두 20마리의 개를 복용하여 인공감염 실험을 실시하였다. 이들 개를 대조군, 감염군, 재감염군으로 나눈 다음 18마리의 개에 10,000개씩 피설유충을 일차감염시켜 그중 5마리는 5일, 1주, 4주 및 6주에 도살하였으며 9주후에 다시 5,000개의 피예유충을 먹인 재감락수의 개 13마리는 1일, 3일, 5일, 1주, 2주, 4주, 6주 및 8주에 각각 도살하였다. 일차감염군과 재감염군에 있어서 충체회수률과 분포를 관찰하였다. 또한 이들 사병변의 소견을 호오적, 광학현미경 및 주사현미경적으로 관찰하였다. 결과를 요약하면 다음과 같다. 1. 충체회수률은 일차감염군에서 19.8%∼37.8%로 평균 충체회수률은 28.9%이었다. 한편 재감염상의 1일, 3일 및 5일에서의 미성숙 충체회수률은 6.3%∼16.3%로 평균 충체회수률은 12.9%이었으며, 성숙 충체회수률은 21.4%∼26.2%로 평균 충체회수률은 23.6%로 나타나 미성숙충체와 성숙충체 회수률의 비는 1 : 1.83이었다. 충체의 기생부위는 일차감염군에서 십이지장, 공장 및 회장상부에 한정되었으나 재감염군에서는 회장하부까지 연장되었다. 2. 상한적 병리소견으로 장관의 확장, 가로주름의 소실, 개수상의 장내용물, 장막림프절 및 Peyer씨 림프조직의 고대가 일차감영군의 5일 및 1주에 나타났으나 4주후에는 거의 소실되었다. 재감염군에서도 이들 소견이 초기에 나타났으나 일차감염군과 비교하면 그 소견이 농징하였으며 2주후에는 소실되었다. 3. 현징경적 병리소견으로 초기의 병변은 소정막에 국한되었으며 선와상피의 비후를 동반한 융모위축과 기질와 변화, 염증세계침윤 및 부종형성이 관찰되었다. 한편 재감염군에 있어서 정막 특히 섬모의 변화는 일차감염군과 비교할 때 그 소견이 경미하였다. 4. 주사현미경적으로 일차감염군에 있어서 섬모위축이 재확인되었으며 융모사이에서 충체를 발견할 수 있었다. 6주후에는 섬모가 거의 정상상태로 회복되었다. 그러나 재감량변에서 융모변화는 그 정도가 심하지 않았다. 이상의 결과에서 소위 자가치유 또는 자연치유 현상은 개의 요꼬가와흡충의 일차감염군과 재감염군에서 나타나지 않았다. 장병변의 경시적 관찰을 통하여 숙주면역은 요점막 회복에 관여하는 것 같았으며 특히 미성숙충체의 Lieberkiihn씨 선준 침입이 융모의 병적 변화에 일차적 원인일 것으로 추측하였다.

• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.453-455
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• 2013

Heartworm infection is a fatal disease causing heart failure and pulmonary diseases in dogs. This heartworm infection can also occur in wild carnivores including Raccoon dogs. Recent study found that relatively high prevalence rate in wild Raccoon dog population. Therefore, this study was designed to evaluate the prevalence rate of D. immitis in free-roaming Raccoon dogs and the recovery rate of microfilariae in infected Raccoon dogs in Korea. Overall prevalence rate of D. immitis in Korean Raccoon dogs was 17.8%. Prevalence rate in male Raccoon dogs was 21.8%, while that in female Raccoon dogs was 12.8%. Microfilariae were not detected in 17 Raccoon dogs having positive in heartworm antigen test. Our study result suggested that the prevalence rate of D. immitis in Korea is twice higher than that of Japan. In addition, microfilaremia is rare in Raccoon dogs as commonly noticed in cats.

• Journal of Chest Surgery
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• v.33 no.11
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• pp.881-885
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• 2000

배경: 승모판막 질환에 동반된 심방세동의 경우 그 기간이 길면 승모판막 질환을 수술하여도 동성 율동으로 전환될 가능성이 매우 적다. 본 연구는 승모판막 질환에 동반된 심방세동에 대한 변형 Maze 수술후 장기 결과와 심방세도의 재발에 미치는 요인을 조사 하고자 하였다. 대상 및 방법: 1990년부터 1996년까지 승모판막 질환과 동반된 심방세동으로 외과적 요법을 시행받은 35명의 환자를 대상으로 하였다. 심방세동의 평균 유병기간은 평균 7.7$\pm$4.5년이었고 수술은 승모판막 대치술 34례(재수술 3례)와 승모판막 성형술 1례를 시행하였고 승모판 질환 수술 외에 동반 수술로는 삼첨판륜 성형술 4례, 삼첨판막 대치술 3례 였다. 심 방세동에 대한 수술은 좌측 폐정맥 부위는 격리하지 않는 변형 Maze 수술을 시행하였다. 수술 후 동성 율동으로 회복여부, 심방세동의 재발에 미치는 요인과 장기 결과를 분석하였다. 결과: 수술 직후 2례를 제외한 33례(93.9%)에서 동성율동으로 돌아왔으나 수술 후 퇴원 전에 12례에서 심방세동이 재발되었다. 수술환자중 1례에서 수술 후 3일에 동성 정지에 따른 심정지가 발생하여 소생되었으나 뇌손상으로 수술 후 15일에 사망하였다. 심방세동이 재발된 경우 수술 후 약 2개월에서 6개월 사이에 항부정맥 약물(mquinidine)과 전기적 제세동으로 치료하여 12례중 10례에서 동성 율동으로 돌아온 환자는 항부정맥 약물을 모두 중단하 였으며, 수술 후 3년에서 9년(평균 71.1$\pm$17.5개월) 추적 관찰 중 9례에서 심방세동이 재발되어 장기간 동성 율동이 유지된 환자는 34명중 25명으로 73.5%이었다. 승모판 질환이 있던 환자에서 수술 후 심방세동의 재발에 미치는 요인들을 조사한 결과 수술전 심방세동의 기간(동성율동 유지군 : 재발군=6.3년 : 10.3년, P=0.008)과 수술 전 단순 흉부 X선상 심흉비율(0.58 : 0.72, p=0.009)은 통계학적으로 유의하게 나타났으나 심초음파 검사상 좌심방의 직경(57.2mm : 77.4mm, p=0.106)은 통계학적 유의성이 없었다. 결론: 심방세동이 있는 환자에서 동반 질환 수술시 병행하여 수술한다면 정상 동성 율동으로 회복될 기회를 증가시킬 수 있는 유용한 수술법으로 생각된다. 그러나 수술후 재발률을 감소시키기 위하여 적절한 술기의 변형에 대한 연구와 약물요법의 병행을 고려하여야 할 것으로 사료된다.

• Membrane Journal
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• v.25 no.4
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• pp.358-366
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• 2015

Flat membrane with $0.4{\mu}m$ pore size was prepared with PVdF (polyvinylidene fluoride) nanofiber, which has the advantages such as excellent strength, chemical resistance, nontoxic, non-combustibility. After that, spiral wound module was manufactured with it including a woven paper. Effect of pH was studied by comparing permeate fluxes and rejection rates of the spiral wound module using simulation solution including kaolin and humic acid. The recovery rate and filtration resistance were calculated after water back-washing at the end of filtration experiment. In addition, after the water filtrated by the spiral wound module was passed through a column filled with GAC (granular activated carbon), adsorption effect of GAC was investigated by measuring the turbidity and $UV_{254}$ absorbance.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.470-477
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• 2015

This study was carried out to investigate the change of dimensional stability of thermally compressed Korean pine (Pinus koraiensis Sieb. et Zucc.) wood by post heat treatment. Specific gravity of compressed wood was notably increased with thermal compression. In the compression set 50%, compressed Korean pine showed a specific gravity of 0.84. The amount of water absorption and swelling of thermally compressed Korean pine decreased with increasing temperature and time of the heat treatment. Set recovery also decreased with increasing temperature and time of heat treatment. Thermally compressed Korean pine that heat-treated in $120^{\circ}C$ for 24 hours showed a set recovery of 3.8%, whereas non-treated group showed 11.5%. Therefore, it was confirmed that the thermal treatment was a very effective method for the dimensional stability of the heat compressed wood.