• Archives of Plastic Surgery
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• 제50권4호
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• pp.354-360
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• 2023

Background The Island transverse rectus abdominis musculocutaneous (TRAM) flap is well vascularized with very reliable blood flow, because all perforators of the zone I are included when it is harvested. The number of perforators, topographic mapping, and their relationship with reconstructed outcomes were investigated. Methods Fifty patients with Island TRAM breast reconstruction from September 2021 to August 2022 were investigated. The zone I was divided into a total of eight sections. Under the loupe magnification, all perforators larger than 0.5 mm in zone I were counted with fine dissection, and photographs were taken in background of vessel loops. Complications like flap necrosis, seroma, and hematoma were also investigated. Result There are 12 ideal perforators on average in zone I such as one perforator in section I, II, IV, V, VI, VIII, and three perforators in section III and VII. However, two perforators (M6 and L6) below arcuate line were sacrificed in the time of flap harvest to prevent hernia. Island TRAM included 10 perforators on average (5 perforators in each side) above arcuate line to be transferred to the recipient site. Only minor complications were identified. Conclusion The Island TRAM flap includes 10 perforators to get the vigorous blood flow. The periumbilical to upper medial perforators become more dominant in the perfusion of the flap after deep inferior epigastric artery division. Well preserved perforators will guarantee the satisfactory breast reconstruction with the least complication.

• 대한기계학회논문집A
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• 제28권10호
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• pp.1435-1450
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• 2004

The investigation, which includes the material homogenization and the calculation of local stress concentration of long-fibrous composites in a microscopic level, has been performed to analyze the behavior of fiber-reinforced composites by using finite element method. In order to carry out this study, the finite element models of composites have been generated by the idealized arrays as square and hexagonal-packed type. In the FE analysis, the boundary conditions of micromechanical finite element method(MFEM) have been defined and verified by comparing with the results from multi-cells, and the effective material properties of composites composed of graphite/epoxy have been also evaluated by rules of mixture. For acquiring the relation between the global and local behaviors of composites, the magnifications of strain, stress, and interfacial stress of composites subjected to a longitudinal and transverse loading respectively have been calculated. And the magnifications have been proposed as the stress concentration in the microscopic level at composite material.

• Structural Engineering and Mechanics
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• 제77권1호
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• pp.1-17
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• 2021

The influence of prestress force on the fundamental frequency and static deflection shape of uncracked Prestressed Concrete (PC) beams with a parabolic bonded tendon was examined in this paper. Due to the conflicts among existing theories, the analytical solutions for properly considering the dynamic and static behavior of these members is not straightforward. A series of experiments were conducted for a total period of approximately 2.5 months on a PC beam made with high strength concrete, subsequently and closely to the 28 days of age of concrete. Specifically, the simply supported PC member was short term subjected to free transverse vibration and three-point bending tests during its early-age. Subsequently, the experimental data were compared with a model that describes the dynamic behavior of PC girders as a combination of two substructures interconnected, i.e., a compressed Euler-Bernoulli beam and a tensioned parabolic cable. It was established that the fundamental frequency of uncracked PC beams with a parabolic bonded tendon is sensitive to the variation of the initial elastic modulus of concrete in the early-age curing. Furthermore, the small variation in experimental frequency with time makes doubtful its use in inverse problem identifications. Conversely, the relationship between prestress force and static deflection shape is well described by the magnification factor formula of the "compression-softening" theory by assuming the variation of the chord elastic modulus of concrete with time.

• 대한방사선기술학회지:방사선기술과학
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• 제38권1호
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• pp.1-6
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• 2015

Whole spine scanography(WSS)는 전신에 X선을 조사하는 검사로 치료기간 동안 빈번한 X선 조사가 이루어지는 검사이다. 일반촬영 분야에서는 많은 X선이 전신에 조사되는 검사이다. 따라서 논문에서는 Auto image pasta기법의 디지털 WSS 검사에서 환자의 검사방향에 따른 유효선량과 장기선량을 전산모사를 통하여 평가하였고, 영상에서 척추의 확대도와 각도의 변화를 평가하였다. 전후면 자세에서의 평균 유효선량은 0.069 mSv였고, 후전면 자세에서 평균 유효선량은 0.0361 mSv로 약 2배의 차이를 보였다. 전후면 자세에서 남성의 평균 유효선량은 0.089 mSv, 여성에 대한 평균 유효선량은 0.431 mSv로 나타났고, 후전면 자세에서 남성의 평균 유효선량은 0.050 mSv, 여성에서는 0.026 mSv로 나타났다. 확대율에서는 후전면 자세에서 전후면 자세에 비해 5%정도 확대 되었으나 각도에는 큰 변화를 보이지 않았다. 따라서 임상 환경에서 동일한 검사조건에서 환자의 자세를 변화시키는 것만으로도 환자의 피폭선량을 감소시킬 수 있음을 확인하였다. 특히 WSS와 같이 치료기간 동안 반복되는 검사에서 환자의 피폭선량 최적화를 위하여 검사 프로토콜의 재정립이 필요함을 확인하였다.

• 대한디지털의료영상학회논문지
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• 제12권2호
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• pp.119-125
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• 2010

In order to demonstrate the value of long-distance radiography, we have studied how distance affects images in chest frontal radiography and compared short-distance and long-distance images in chest lateral radiography. Cardiothoracic ratio(CTR %) of 50 patients with no disease in the chest(10 each at the age of 20~60) were evaluated in Supine AP(100 cm), Sitting AP(100 cm), Sitting AP(180 cm), and Erect PA(180 cm). In lateral radiography, we evaluated and compared left lateral radiography(100 cm and 180 cm) of the patients based on the horizontal maximum of the heart. The average value of CTR(%) were 0.48 in Erect PA(180 cm), 0.52 in Supine AP(100 cm), 0.50 in Sitting AP(100 cm), 0.49 in Sitting AP(180 cm), which were Supine AP(100 cm) > Sitting AP(100 cm) > Sitting AP(180 cm) > Erect PA(180 cm). The average value of Maximum transverse diameter of left of the cardiac(MLD), which showed how much axis of spine was slanted to the left, was 90.67 mm in Erect PA(180 cm), 103.92 mm in Supine AP(100 cm), 93.54 mm in Sitting(100 cm), 89.84 mm in Sitting AP(180 cm), 58.11 mm in the minimum value and 118.79 mm in the maximum value. The average value of Maximum transverse diameter of right side of the cardiac(MRD), which suggested how much axis of spine was slanted to the right, was 47.18 mm in Erect PA(180 cm), 48.12 mm in Supine AP(100 cm), 44.98 mm in Sitting AP(180 cm), and the minimum value 26.84 mm and the maximum value 65.30 mm. There was no standard method to calculate; therefore, the horizontal maximum of the heart was used for lateral radiography. The average value was 121.07 mm in 100 cm and 109.76 mm in 180 cm. Sitting AP(180 cm) among the types was closest to C-PA(180 cm). As a result, during C-AP radiography, long-distance radiography lessened shadow of the heart more than that of short distance, Sitting position more than Supine position.

• Journal of Chest Surgery
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• 제34권7호
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• pp.534-538
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• 2001

배경: 기관의 크기와 기관주위의 정상형태에 대한 지식은 임상에서 기도나 호흡관리, 그리고 기관재건술을 시행하는데 중요한 정보가 된다. 흉부 단순촬영은 기관의 직경을 재는 간단한 방법이지만 그 상이 확대되는 경향과 측면촬영에서 어깨와 상이 겹쳐서 나타나는 단점이 있다. 이에 저자들은 한국인 정상 성인의 기관의 정상치를 알기 위해 흥부 전산화 단층촬영을 이용하여 기관의 내경과 단면적을 측정하였다. 대상 및 방법: 남자 43명과 여자34명을 대상으로 하여 각각 나이에 따라 20~39세는 제 1군, 40~59세는 제2군, 60세 이상은 제 3군으로 구분하였다. 흉부 유입구와(Level 1) 대동맥궁에서(Level 2) 흉부 전산화 단층촬영을 이용하여 각각 전후경과 횡경을 재고 그 단면적을 구하였다. 결과: level 1에서 한국인 성인 남자의 기관의 전후경은 15.95$\pm$2.99 m, 횡경은 17.72$\pm$2.13 m이었고, 여자의 경우 전후경은 15.56$\pm$2.12 m, 횡경은 14.18$\pm$2.07mm로 남녀간에 유의한 차이가 있었다(p 0.05). Level 2에서 남자의 전후경은 19.77$\pm$2.57 m, 횡경은 18.02$\pm$2.19 mm이었고 여자의 전후경은 15.35$\pm$1.82 m, 횡경은 15.00$\pm$1.60 mm로 남녀간에 유의한 차이가 있었다 (p 0.05). 기관단면적은 남자가 각 Level에서 279.14$\pm$61.37 $\textrm{mm}^2$(Level 1), 281.93$\pm$63.97 $\textrm{mm}^2$(level 2)였고, 여자가 173.29$\pm$35.81 $\textrm{mm}^2$(Level 1), 181.88$\pm$34.74 $\textrm{mm}^2$(Level 2)로 두 위치에서 단면적은 남녀간에 유의한 차이가 있었다(p 0.05). 기관의 각각의 위치에서 내경과 단면적은 연령군에 따라 고연령층에서 증가하는 추세를 나타내었으나 통계적인 의미는 없었다. 결론: 한국 정상 성인의 기관내경과 단면적의 크기는 성별에 따라 통계적으로 유의한 차이가 있었으나 연령에 따른 차이는 없었고, 전산화 단층촬영은 기관의 내경과 단면적의 크기를 얻는데 비교적 정확하고 안전한 방법이라 생각된다.