• Asian Pacific Journal of Cancer Prevention
• /
• 제17권8호
• /
• pp.4049-4057
• /
• 2016

Background: High-risk human papillomaviruses (HR-HPV), particularly types 16 and 18, have been found to play an important role in head and neck cancer, including oropharyngeal squamous cell carcinoma (OPSCC) and oral squamous cell carcinoma (OSCC). p16, a cell cycle inhibitor, has been postulated as a surrogate marker for HR-HPV, since p16 is aberrantly overexpressed in such lesions, especially in HR-HPV-positive OPSCC. However, p16 as a surrogate marker for HR-HPV infection in cancers of the oral cavity remains controversial. Objective: The objectives of the study were to investigate the expression of p16 and the presence of HR-HPV in OSCC and oral verrucous carcinoma (VC) and to determine if p16 could be used as a surrogate marker for HR-HPV. Materials and Methods: Forty one formalin-fixed, paraffin-embedded tissues of OSCC (n=37) or VC (n=4) with clinical and histopathologic data of each case were collected. Expression of p16 was determined by immunohistochemistry, focusing on both staining intensity and numbers of positive cells. The presence of HPV types 16 and 18 was detected by polymerase chain reaction (PCR). Descriptive statistics were employed to describe the demographic, clinical, and histopathologic parameters. Associations between p16 overexpression, HR-HPV and all variables were determined by Fisher's exact test, odds ratios (ORs) and corresponding 95% confidence intervals (CIs). In addition, the use of p16 as a surrogate marker for HR-HPV was analyzed by sensitivity and specificity tests. Results: p16 was overexpressed in 8/37 cases (21.6%) of OSCC and 2/4 cases (50%) of VC. HPV-16 was detected in 4/34 OSCC cases (11.8%) and HPV-18 was detected in 1/34 OSCC cases (2.9%). Co-infection of HPV-16/18 was detected in 1/4 VC cases (25%). Both p16 overexpression and HR-HPV were significantly associated with young patients with both OSCC and VC (p<0.05, OR 20, 95% CI 1.9-211.8; p<0.05, OR 23.3, 95% CI 2.4-229.7, respectively). p16 was able to predict the presence of HPV-16/18 in OSCC with 40% sensitivity and 79.3% specificity and in VC with 100% sensitivity and 66.7% specificity, respectively. Conclusions: p16 overexpression was found in 24.4% of both OSCC and VC. HR-HPV, regardless of type, was detected in 15.8% in cases of OSCC and VC combined. The results of sensitivity and specificity tests suggest that p16 can be used as a surrogate marker for HR-HPV in OSCC and VC.

• 한국지반신소재학회논문집
• /
• 제17권2호
• /
• pp.33-40
• /
• 2018

지반구조물에서는 흙과 구조물 사이의 상호 마찰 특성이 구조물에 작용하는 하중과 저항 분석에 큰 영향을 미친다. 일반적으로 지반구조물의 주재료로서 콘크리트 또는 강재가 많이 사용되며, 흙 입자 크기와 비교하여 마찰면의 거칠기 정도에 따라 경계면 마찰 특성이 큰 차이를 보인다. 특히 비신장성 보강재를 사용하는 보강토 옹벽, 말뚝 주면, 옹벽면 등의 지반구조물에 대해서는 흙과 구조물 사이의 마찰특성을 합리적으로 분석하여 구조물의 안전성을 확보하여야 한다. 구조물면과 사질토 사이의 마찰특성에 대하여 보다 정확한 예측식을 제시하고 이 예측식이 가지고 있는 불확실성을 제시하는 것은 지반-지반구조물의 신뢰성 분석에 필수적이다. 따라서 본 연구에서는 기존 양질의 연구 문헌들에 보고된 흙과 거칠기가 다른 면 사이의 마찰실험결과를 분석하여, 강재와 사질토 사이의 첨두 경계면 마찰각을 구하는 식을 제안하였다. 첨두 경계면 마찰각을 결정하는 주요인자는 경계면의 상대조도, 흙의 상대밀도, 구속압, 한계상태 경계면 마찰각이다. 본 연구에서 개발한 첨두 경계면 마찰각 예측식에 대한 불확실성을 통계적으로 Goodness-of-fit 시험 결과를 반영하여 평가하였다.

• 구강회복응용과학지
• /
• 제22권2호
• /
• pp.173-180
• /
• 2006

Objectives The aim of this study is to compare the quality of root canal preparation completed using MFile-$System^{(R)}$ instrument ( Komet, Gebr.Brsaseler, Germany) and conventional stainless steel file in the canals of Maxillary molar teeth that had a canal curvature between $25^{\circ}$ or more Materials & Methods Buccal canals of 24 first and second maxillary molar teeth, extracted for periodontal and prosthetic reasons were used. Tissue fragments and calcified debris were removed from teeth by scaling and the teeth were stored in 10% formalin solution for 24 hour. Then, teeth were stored in saline until used. To be included the roots had to have completed formed apices and angle of curvature ranging between $25^{\circ}$ or more according to the criteria described by Schneider(1971). Palatal and Second mesiobuccal canals were not included. Teeth were embedded into transparent acrylic. The teeth were randomly divided into two experimental groups. All teeth were scanned by Dental CT (PSR9000N, Asahi, Japan) to determine the root canal shape before instrumentation. Image slices were prepared from the apical end point to the pulp chamber. The first two sections were 2 mm from the apical end of root and 2 mm below the orifice. Further section was recorded, dividing the distance between the sections of apical and coronal levels into two equal lengths. 12 teeth were instrumented using stainless steel fileand another 12 teeth were instrumented using MFile-$System^{(R)}$. Following the completion of the instrumentation, the teeth were again scanned and compared with the cross sectional images taken prior to canal preparation. Amount of transportation and centering ability was assessed. Student's t-test was used for statistical analysis. Result Less transportation occurred with MFile-$System^{(R)}$ rotary instrumentation than stainless steel instrument. MFile-$System^{(R)}$ had better centering ability than stainless steel instrument. Conclusion MFile-$System^{(R)}$ rotary instrumentation transported canals less and had good centering ability.

• 콘크리트학회논문집
• /
• 제21권6호
• /
• pp.753-761
• /
• 2009

이 논문은 철근콘크리트 휨부재의 인장겹침이음 영역에서의 정착저항능력에 대한 콘크리트 강도와 피복두께의 영향을 알아보기 위하여 총 24개의 beam-end 실험체의 실험 결과를 정리 분석한 것이다. 콘크리트 강도가 증가할수록 부착응력이 커지고 전달길이가 줄어든다는 부착특성과 얇은 피복에서 쉽게 발생하는 쪼갬균열 및 취성적인 균열 진전과 같은 균열거동을 근거로 하여 현행 설계기준의 등분포부착응력 가정에 의한 정착길이 규정을 고강도 콘크리트에도 그대로 적용할 수 있는지 조사하였다. 그 결과 콘크리트 강도에 따른 정착저항능력은 피복두께의 영향을 크게 받고 있으며, 고강도 콘크리트에서는 현행 설계기준 규정보다 짧은 겹침이음길이를 갖더라도 충분한 안전율을 확보하는 것으로 나타났다. 이러한 실험 결과로부터 고강도 콘크리트의 정착길이는 제곱근 압축강도의 반비례가 아닌 압축강도에 직접적으로 반비례함을 확인하였으며, 현 설계기준에서 보통강도 콘크리트에 적용하는 동일 매입길이에 대한 등 분포부착응력 가정이 아닌 새로운 정착길이 계산식을 제안하였다.

• 대한전자공학회논문지SP
• /
• 제47권5호
• /
• pp.62-73
• /
• 2010

본 논문은 ITU-T SG16 Q.10에서 표준화 진행 중인 G.711.1 및 G.722 슈퍼와이드밴드 확장 코덱의 후보 코덱 알고리즘에 대한 것으로, 제안된 후보 코덱은 기존 ITU-T 광대역 코덱 G.711.1 및 G.722와 비트스트림 호환성을 지원함과 동시에 슈퍼와이드밴드 확장 계층을 통해 50-14,000 Hz에 해당하는 슈퍼와이드밴드 신호를 부호화한다. 본 후보 코덱 알고리즘은 기존 광대역 코덱과 비트스트림 호환성을 위한 핵심 계층 부호화 알고리즘과 선형 예측 기반 정현파 코딩을 이용한 슈퍼와이드밴드 확장 알고리즘으로 이루어져 있다. 제안된 슈퍼와이드밴드 확장 코덱은 5 ms의 프레임에서 동작하며 핵심 코덱에 따라 64, 80, 96 및 112 kbit/s로 이루어진 네 개의 슈퍼와이드밴드 비트율을 제공한다. 각 비트율에 해당하는 비트스트림들은 내장형 구조를 가지고 있어 별도의 상호부호화 과정 없이 간단한 비트스트림 절단을 통해 핵심 코덱 비트스트림으로 변환할 수 있다. 제안된 코덱 알고리즘은 짧은 알고리즘 지연과 낮은 복잡도를 가지며, ITU-T에서 실시된 G.711.1/G.722 슈퍼와이드밴드 확장 코덱 자격 시험을 통과하였다.

• 한국과학교육학회지
• /
• 제23권2호
• /
• pp.190-199
• /
• 2003

본 연구는 집단 유전(하디-바인베르크 법칙)개념 학습에 있어서 귀납적 지도 방법과 연역적 지도방법에서 효과의 차이를 알아보고 학습자의 인지적 특성에 맞는 수업모형에 대한 시사점을 얻고자 하였다. 연구대상은 고등학교 남학생 180이며 90명은 귀납식 수업모형, 90명은 연역식 수업모형으로 수업을 하였다. 인지적 특성을 파악하기 위해서 논리적 사고력 검사(GALT)와 인지양식 검사(GEFT)를 실시하였다. 본 연구의 결과는 다음과 같다. 첫째, 귀납적인 지도 방법이 연역적인 지도방법에 비해서 유의도 수준 0.01에서 개념 검사 및 성취도 검사에서 유의미하게 효과적인 것으로 나타났다. 둘째, 귀납적 지도방법이 형식적 조작기의 학생과 장 독립적 학생에게 있어서 연역적 지도방법에 비해 더 효과적인 것으로 나타났다. 셋째, 인지수준이 과도기에 있는 학습자와 장의 존적인 학습자에게 있어서는 연역적 수업이 평균으로 볼 때는 효과적이었으나 통계적으로는 의미가 없었다. 이러한 결과는 교사들의 학습전략을 다양화 및 학습자의 인지수준과 인지양식에 대한 고려가 필요함을 시사해준다.

• Journal of Periodontal and Implant Science
• /
• 제26권4호
• /
• pp.799-821
• /
• 1996

The ultimate goal of periodontal treatment has been to facilitate regeneration of diseased periodontal tissues, destroyed by inflammatory periodontal disease. For regeneration of the periodontium to occur, all of component tissues must be restored to their original position and architecture. Growth factors which were known to promote the cellular processes, ie, proliferation, migration and matrix synthesis, have been in the spotlight of current periodontics. Platelet-derived growth factor(PDGF) stimulates collagen and non collagen protein synthesis, migration and proliferation of periodontal ligament cells. Insulin-like growth factor(IGF) has potentials to induce collagen and bone matrix synthesis so that it regulates normal bone remodeling. Application of the combination have been known to facilitate formation of bone and cementum, and to synergistically interact to promote coronal migration and proliferation of periodontal ligament cells. These two growth factors have been reported to exhibit positive effect in the periodontally diseased teeth or class m furcation defects. The aim of the present study was to test the hypothesis that PDGF-BB alone or the combination of PDGF-BB and IGF-I can predictably enhance regeneration of the periodontium in the dehiscence defect. Following the resection of premolars, roots were embedded. After 12 weeks of healing period, standardized experimental $4{\times}4mm$ dehiscence defects were created on the mid-facial of the premolar roots in each of 4 young adult dogs. In control group, only methylcellulose gel was inserted in the defects. In experimental group I and II, gel with $2{\mu}g$ of PDGF-BB or $2{\mu}g$ of PDGF-BB and $1{\mu}g$ of IGF-I was inserted in the defects, respectively. At 8 weeks postsurgery, the dogs were sacrificed. The results were observed histologically and analyzed histomorphometrically.The results of this study were as follws. 1. The new cementum formation was $1.26{\pm}0.69mm$ in the control group, $1.80{\pm}0.84mm$ in the experimental group I, $1.93{\pm}0.51mm$ in the experimental group II. The experimental group III, the experimental group I, the control group were in the order of cementum formation without statistically significant differences between control and all experimental groups. 2. The new bone formation was $1.00{\pm}0.53mm$ in the control group, $1.53{\pm}0.63mm$ in the experimental group I, $l.33{\pm}0.45mm$ in the experimental group II. The experimental group I, the experimental group II, the control group were in the order of bone formation without statistically significant differences between control and all experimental groups. 3. The root resorption was $1.12{\pm}0.64mm$ in the control group, $1.34{\pm}0.73mm$ in the experimental group I, $0.79{\pm}0.59mm$ in the experimental group II without statistically significant differences between control and all experimental groups. These results suggested that the use of PDGF-BB alone or PDGF-BB and IGF-I in the dehiscence defects might facilitate periodontal regeneration in some degree, but has not shown statistically significant results.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2003년도 추계학술발표대회 논문집
• /
• pp.46-49
• /
• 2003

Cu have been widely used as signal transmission materials for electrical electronic components owing to its high electrical conductivity. However, it's size have been limited to small ones due to its poor mechanical properties, Until now, strengthening of the copper at toy was obtained either by the solid solution and precipitation hardening by adding alloy elements or the work hardening by deformation process. Adding the at toy elements lead to reduction of electrical conductivity. In this aspect, if carbon nanofiber is used as reinforcement which have outstanding mechanical strength and electric conductivity, it is possible to develope Cu matrix nanocomposite having almost no loss of electric conductivity. It is expected to be innovative in electric conduct ing material market. The unidirectional alignment of carbon nanofiber is the most challenging task developing the copper matrix composites of high strength and electric conductivity In this study, the unidirectional alignment of carbon nanofibers which is used reinforced material are controlled by drawing process in order to manufacture the intermediary materials for the carbon nanofiber reinforced Cu matrix nanocomposite and align mechanism as well as optimized drawing process parameters are verified via experiments and numerical analysis. The materials used in this study were pure copper and the nanofibers of 150nm in diameter and of $10~20\mu\textrm{m}$ In length. The materials have been tested and the tensile strength was 75MPa with the elongation of 44% for the copper it is assumed that carbon nanofiber behave like porous elasto-plastic materials. Compaction test was conducted to obtain constitutive properties of carbon nanofiber. Optimal parameter for drawing process was obtained by experiments and numerical analysis considering the various drawing angles, reduction areas, friction coefficient, etc Lower reduction areas provides the less rupture of cu tube is not iced during the drawing process. Optimal die angle was between 5 degree and 12 degree. Relative density of carbon nanofiber embedded in the copper tube is higher as drawing diameter decrease and compressive residual stress is occurred in the copper tube. Carbon nanofibers are moved to the reverse drawing direct ion via shear force caused by deformation of the copper tube and alined to the drawing direction.

• 한국식품과학회지
• /
• 제31권4호
• /
• pp.906-911
• /
• 1999

저선량으로 조사된 곡류의 방사선 조사 여부를 판별 하는데 DNA 'Comet Assay'의 활용이 가능한지를 검토하였다. 참깨, 들깨, 밀, 보리 및 쌀을 0, 0.1, 0.3, 0.5, 0.7, 1.0 kGy로 조사하여 시료로 사용하였다. 시료에 PBS 용액을 가하여 세포 현탁액을 조제하고 agarose gel과 혼합하여 microscope slide 상에서 lysis한 후 전기영동하여 염색한 다음 DNA 절편의 이동에 의해 형성된 ‘comet’의 tail length를 측정하여 분석하였다. 0.3 kGy 이상으로 조사한 모든 시료에서 tail length가 비조사한 시료와 차이를 나타내어 조사 여부를 확실히 판별할 수 있었다. 또한 비조사된 시료에서는 tail이 없거나 아주 짧은 tail을 가진 세포들이 관찰되었으며, 조사된 시료에서는 조사선량의 증가에 따라 DNA의 손상정도가 증가함으로서 tail length가 길어지는 것이 관찰되었다. 특히 참깨, 들깨 및 밀의 경우는 0.1 kGy의 낮은 조사선량에서도 현미경을 통하여 육안으로 비조사한 시료와의 구별이 가능하였다. 따라서 DNA 'Comet Assay'는 간단하고 신속하며 비교적 저렴하게 실시할 수 있는 곡류의 방사선 조사 여부를 판별하는 데 활용할 수 있음을 확인하였다.

• Interaction and multiscale mechanics
• /
• 제2권1호
• /
• pp.69-89
• /
• 2009

Reinforced and prestressed concrete (RC and PC) thin walls are crucial to the safety and serviceability of structures subjected to shear. The shear strengths of elements in walls depend strongly on the softening of concrete struts in the principal compression direction due to the principal tension in the perpendicular direction. The past three decades have seen a rapid development of knowledge in shear of reinforced concrete structures. Various rational models have been proposed that are based on the smeared-crack concept and can satisfy Navier's three principles of mechanics of materials (i.e., stress equilibrium, strain compatibility and constitutive laws). The Cyclic Softened Membrane Model (CSMM) is one such rational model developed at the University of Houston, which is being efficiently used to predict the behavior of RC/PC structures critical in shear. CSMM for RC has already been implemented into finite element framework of OpenSees (Fenves 2005) to come up with a finite element program called Simulation of Reinforced Concrete Structures (SRCS) (Zhong 2005, Mo et al. 2008). CSMM for PC is being currently implemented into SRCS to make the program applicable to reinforced as well as prestressed concrete. The generalized program is called Simulation of Concrete Structures (SCS). In this paper, the CSMM for RC/PC in material scale is first introduced. Basically, the constitutive relationships of the materials, including uniaxial constitutive relationship of concrete, uniaxial constitutive relationships of reinforcements embedded in concrete and constitutive relationship of concrete in shear, are determined by testing RC/PC full-scale panels in a Universal Panel Tester available at the University of Houston. The formulation in element scale is then derived, including equilibrium and compatibility equations, relationship between biaxial strains and uniaxial strains, material stiffness matrix and RC plane stress element. Finally the formulated results with RC/PC plane stress elements are implemented in structure scale into a finite element program based on the framework of OpenSees to predict the structural behavior of RC/PC thin-walled structures subjected to earthquake-type loading. The accuracy of the multiscale modeling technique is validated by comparing the simulated responses of RC shear walls subjected to reversed cyclic loading and shake table excitations with test data. The response of a post tensioned precast column under reversed cyclic loads has also been simulated to check the accuracy of SCS which is currently under development. This multiscale modeling technique greatly improves the simulation capability of RC thin-walled structures available to researchers and engineers.