• 열처리공학회지
• /
• 제35권3호
• /
• pp.139-149
• /
• 2022

In the automobile and shipbuilding industries, various materials and components require superior surface strength, excellent wear resistance and good resistance to repeated loads. To improve the surface properties of the materials, various surface heat treatment methods are used, which include carburizing, nitriding, and so on. Among them, carburizing treatment is widely used for structural steels containing carbon. The effective carburizing thickness required for materials depends on the service environment and the size of the components. In general, however, there is a limit in evaluation of the surface properties with a standardized mechanical test method because the thickness or cross-sectional area of the carburized layer is limited. In this regard, the nanoindentation technique has lots of advantages, which can measure the mechanical properties of the material surface at the nano and micro scale. It is possible to understand the relationship between the microstructural change in the hardened layer by carburizing treatment and the mechanical properties. To be spread to practical applications at the industrial level, in this paper, the principle of the nanoindentation method is described with a representative application for analyzing the mechanical properties of the carburized material.

• 대한소아치과학회지
• /
• 제47권2호
• /
• pp.109-119
• /
• 2020

이 후향적 연구는 chloral hydrate, hydroxyzine 및 N₂O/O₂ 조합을 이용한 진정 치료를 시행한 149명 환아의 188회 진정 치료의 효과와 부작용에 대해 알아보고, 효과와 부작용에 영향을 미칠 수 있는 요소를 확인하고자 하였다. 진정 치료의 효과는 Houpt 분류법을 이용하여 측정하였고, excellent와 good의 경우 효과적으로 분류하였다. 진정 치료 시간을 15분 간격으로 나누어 효과와 부작용을 분석한 결과, 치료 시간이 증가할수록 효과는 감소하고 부작용은 증가하는 것으로 나타났다. 60분 동안의 진정 치료 효과는 57.4% 이었으며, 전체 부작용 발생률은 18.1%이었다. 진정 치료의 효과는 Body mass index(BMI)가 증가할수록 증가하였으며, 술식 시작 시 진정이 되어있는 경우 진정 치료 효과가 높은 것으로 나타났다. 부작용은 나이가 증가할수록 증가하였다. 진정 치료가 2회로 나누어 시행되었을 때, 진정 치료의 횟수는 효과와 부작용에 영향을 미치지 않았다. 진정 치료 시간을 무리하게 연장하는 것은 효과 감소와 부작용 증가를 불러일으킬 수 있으므로 진정 치료를 2회에 나누어 시행하는 것이 필요할 것으로 생각된다. 또한 BMI, 술식 시작 시 진정 여부 및 나이와 같은 진정 효과를 감소시키고 부작용을 증가시키는 요소에 대한 충분한 고려가 선행된 후 진정 치료를 시행하여야 할 것으로 생각된다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권11호
• /
• pp.5823-5828
• /
• 2012

Background: Breast cancer (BC) is one of the most common cancer affecting women worldwide. Although a great deal of progress has been made in the health sciences, early diagnosis, and increasing community awareness, breast cancer remains a life-threatening illness. In order to reduce this threat, breast cancer screening needs to be implemented in all communities where possible. Objective: The purpose of this study was to examine health beliefs, attitudes and behaviors about breast cancer and breast self-examination of Turkish women. Methods: Data were collected from a sample of 656 women, using an adapted Turkish version of Champion's Health Belief Model Scale (CHBMS), between January and May 2011, in Ordu province of Turkey. Results: The results showed that 67.7% of women had knowledge about and 55.8% performed BSE, however 60.6% of those who indicated they practiced BSE reported they did so at irregular intervals. CHBMS subscales scores of women according to women's age, education level, occupation, family income and education level of the women's mothers, family history of breast cancer, friend and an acquaintance with breast cancer, knowledge about breast cancer, BSE and mammography were significantly different. Conclusion: Knowledge of women about the risks and benefits of early detection of breast cancer positively affect their health beliefs, attitudes, and behaviors. Health care professionals can develop effective breast health programs and can help women to gain good health behavior and to maintain health.

• 한국지반공학회논문집
• /
• 제29권1호
• /
• pp.93-107
• /
• 2013

입상체의 열전도도 산정에 관한 연구는 다공질 매질이나 지반공학에서 다양하게 사용될 수 있다. 입상체의 열전도도 산정은 입자들 사이의 에너지 관계에 대한 모사를 통해 "유효 열전도도"를 획득하는 것으로 발전하였다. 본 연구는 불포화토의 유효 열전도도를 산정하기 위해 3차원 개별 요소법을 이용하여 입자를 생성하고 기존 네트워크 모델을 수정하여 적용하였다. 수정된 네트워크 모델을 검증하기 위해 3가지 다른 크기의 글라스 비즈와 주문진사를 이용하여 실내시험을 통해 흙-수분 특성 곡선과 포화도에 따른 시료의 열전도도를 산정하였다. 수정된 네트워크 모델에서는 흙-수분 특성 곡선을 사용하여 입자 사이의 평균 유효 열전달 실린더 반경을 조정하고 모델에 적용하였다. 일련의 실내시험과 수정된 네트워크 모델을 사용하여 결과를 비교한 결과, 흙-수분 특성 곡선을 적용한 네트워크 모델은 주어진 불포화 조건에서 입상체 시료의 유효 열전도도를 합리적으로 모사할 수 있는 것으로 나타났다. 또한, 포화상태의 유효 열전달 실린더 반경 계수로 정규화한 예측식을 제안하였다. 제안한 예측식을 통해 기존 네트워크 모델을 사용하여 불포화 상태에서 입상체의 유효 열전도도를 산정할 수 있다.

• Journal of Korean Neurosurgical Society
• /
• 제60권2호
• /
• pp.211-219
• /
• 2017

Objective : This study aimed to compare the clinical and radiologic outcomes of patients with subaxial cervical injury who underwent anterior cervical discectomy and fusion (ACDF) with autologous iliac bone graft or polyetheretherketone (PEEK) cages using demineralized bone matrix (DBM). Methods : From January 2005 to December 2010, 70 patients who underwent one-level ACDF with plate fixation for post-traumatic subaxial cervical spinal injury in a single institution were retrospectively investigated. Autologous iliac crest grafts were used in 33 patients (Group I), whereas 37 patients underwent ACDF using a PEEK cage filled with DBM (Group II). Plain radiographs were used to assess bone fusion, interbody height (IBH), segmental angle (SA), overall cervical sagittal alignment (CSA, C2-7 angle), and development of adjacent segmental degeneration (ASD). Clinical outcome was assessed using a visual analog scale (VAS) for pain and Frankel grade. Results : The mean follow-up duration for patients in Group I and Group II was 28.9 and 25.4 months, respectively. All patients from both groups achieved solid fusion during the follow-up period. The IBH and SA of the fused segment and CSA in Group II were better maintained during the follow-up period. Nine patients in Group I and two patients in Group II developed radiologic ASD. There were no statistically significant differences in the VAS score and Frankel grade between the groups. Conclusion : This study showed that PEEK cage filled with DBM, and plate fixation is at least as safe and effective as ACDF using autograft, with good maintenance of cervical alignment. With advantages such as no donor site morbidity and no graft-related complications, PEEK cage filled with DBM, and plate fixation provide a promising surgical option for treating traumatic subaxial cervical spine injuries.

• Steel and Composite Structures
• /
• 제32권6호
• /
• pp.807-819
• /
• 2019

In recent earthquakes, the failure of ceiling systems has been one of the most widely reported damage and the major cause of functionality interruption in some buildings. In an effort to mitigate this damage, some scholars have studied a series of ceiling systems including plaster ceilings and mineral wool ceilings. But few studies have involved the backdrop metal ceiling used in some important constructions with higher rigidity and frequency such as the main control area of nuclear power plants. Therefore, in order to evaluate its seismic performance, a full-scale backdrop metal ceiling system, including steel runners and metal panels, was designed, fabricated and installed in a steel frame in this study. And the backdrop metal ceiling system with two perimeter attachments variants was tested: (i) the ends of the runners were connected with the angle steel to form an effective lateral constraint around the backdrop metal ceiling, (ii) the perimeter attachments of the main runner were retained, but the perimeter attachments of the cross runner were removed. In the experiments, different damage of the backdrop metal ceiling system was observed in detail under various earthquakes. Results showed that the backdrop metal ceiling had good integrity and excellent seismic performance. And the perimeter attachments of the cross runner had an adverse effect on the seismic performance of the backdrop metal ceiling under earthquakes. Meanwhile, a series of seismic construction measures and several suggestions that need to be paid attention were proposed in the text so that the backdrop metal ceiling can be better applied in the main control area of nuclear power plants and other important engineering projects.

• 대한치과마취과학회지
• /
• 제5권2호
• /
• pp.101-106
• /
• 2005

Purpose: This retrospective study assessed the effectiveness of submucosal (SM) midazolam (M), oral chloral hydrate (CH), hydroxyzine (H), and nitrous oxide (N) 99 uncooperative pediatric dental patients over 182 sedation sessions. Methods: Selection criteria included good medical health (ASA I), from 2 to 6 years of age, uncooperative behavior, and the need for restorations and dental surgery. The children who was administerated with CH H, N was Group 1 (48 case). The children who was administerated with CH, H, N, M was Group 2 (51 case). All the patients received oral CH (50-70 mg/Kg), H (1 mg/Kg) and N (less than 50%). Additionally the Group 2 received SM midazolam (0.1-0.2 mg/kg). Behavior response was rated as quiet (Q), crying (C), movement (M), or struggling (S) every 5 minutes through operative procedures. Behavior response rating was assigned to Houpt scale of Overall behavior. Data was analyzed using Chi-Square Test. Results: The Group 2 had more effective (88.2%) than the Group 1 (68.8%)(P = 0.05). Also, vomiting response decreased in the Group 2 (94.4%) than those with oral administration of chloral hydrate alone without SM midazolam (77.1%)(P = 0.05). Conclusions: SM midazolam improved the quality of sedation and vomiting response.

• Journal of Korean Neurosurgical Society
• /
• 제41권1호
• /
• pp.7-10
• /
• 2007

Objective : The aim of this study was to determine the efficacy of percutaneous radiofrequency neurotomy[RFN] of ramus communicans nerve in patients suffering from severe low back pain due to osteoporotic compression fracture. Methods : Twenty two patients with lumbar osteoporotic compression fracture who had intractable back pain for less than two weeks and were performed with RFN at L1-L4 from May 2004 to December 2005 were retrospectively analyzed. Clinical outcome using visual analogue scale[VAS] pain scores and modified MacNab's grade was tabulated. Complications related to the procedure were assessed. Results : Twenty-two female patients [age from 63 to 81 years old] were included in this study. The mean VAS score prior to RFN was 7.8, it improved to 2.6 within postoperative time of 48 hours, and the mean VAS score after 3 months was 2.8, which was significantly decreased. Eighteen of 22 patients were graded as excellent and good according to modified MacNab's criteria at final follow up. All patients recovered uneventfully, and the neurologic examination revealed no deficits. Two patients showing poor results worsened in symptom. Percutaneous was performed eventually resulting in symptom improvement. There were no significant complications related to the procedure such as sensory dysesthesia, numbness or permanent motor weakness. Conclusion : RFN is safe and effective in treating the painful osteoporotic compression fracture. in patients with intractable back pain due to lumbar osteoporotic compression fracture, RFN of gray ramus communicans nerve should be considered as a treatment option prior to vertebroplasty.

• Journal of Ginseng Research
• /
• 제42권2호
• /
• pp.199-207
• /
• 2018

Background: Ginseng is a well-known traditional Chinese medicine that has been widely used in a range of therapeutic and healthcare applications in East Asian countries. Microbial transformation is regarded as an effective and useful technology in modification of nature products for finding new chemical derivatives with potent bioactivities. In this study, three minor derivatives of ginsenoside compound K were isolated and the inducing effects in the Wingless-type MMTV integration site (Wnt) signaling pathway were also investigated. Methods: New compounds were purified from scale-up fermentation of ginsenoside Rb1 by Paecilomyces bainier sp. 229 through repeated silica gel column chromatography and high pressure liquid chromatography. Their structures were determined based on spectral data and X-ray diffraction. The inductive activities of these compounds on the Wnt signaling pathway were conducted on MC3T3-E1 cells by quantitative real-time polymerase chain reaction analysis. Results: The structures of a known 3-keto derivative and two new dehydrogenated metabolites were elucidated. The crystal structure of the 3-keto derivative was reported for the first time and its conformation was compared with that of ginsenoside compound K. The inductive effects of these compounds on osteogenic differentiation by activating the Wnt/b-catenin signaling pathway were explained for the first time. Conclusion: This study may provide a new insight into the metabolic pathway of ginsenoside by microbial transformation. In addition, the results might provide a reasonable explanation for the activity of ginseng in treating osteoporosis and supply good monomer ginsenoside resources for nutraceutical or pharmaceutical development.

• Journal of Korean Neurosurgical Society
• /
• 제51권4호
• /
• pp.203-207
• /
• 2012

Objective: The purpose of this prospective study was to evaluate the efficacy and safety of screw fixation without bone fusion for unstable thoracolumbar and lumbar burst fracture. Methods: Nine patients younger than 40 years underwent screw fixation without bone fusion, following postural reduction using a soft roll at the involved vertebra, in cases of burst fracture. Their motor power was intact in spite of severe canal compromise. The surgical procedure included postural reduction for 3 days and screw fixations at one level above, one level below and at the fractured level itself. The patients underwent removal of implants 12 months after the initial operation, due to possibility of implant failure. Imaging and clinical findings, including canal encroachment, vertebral height, clinical outcome, and complications were analyzed. Results: Prior to surgery, the mean pain score (visual analogue scale) was 8.2, which decreased to 2.2 at 12 months after screw fixation. None of the patients complained of worsening of pain during 6 months after implant removal. All patients were graded as having excellent or good outcomes at 6 months after implant removal. The proportion of canal compromise at the fractured level improved from 55% to 35% at 12 months after surgery. The mean preoperative vertebral height loss was 45.3%, which improved to 20.6% at 6 months after implant removal. There were no neurological deficits related to neural injury. The improved vertebral height and canal compromise were maintained at 6 months after implant removal. Conclusion: Short segment pedicle screw fixation, including fractured level itself, without bone fusion following postural reduction can be an effective and safe operative technique in the management of selected young patients suffering from unstable burst fracture.