• The Journal of Advanced Prosthodontics
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• 제14권5호
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• pp.305-314
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• 2022

PURPOSE. The aim of this study was to evaluate the flexural strength of a 3D-printed denture base resin (Cosmos Denture), after different immediate repair techniques with surface treatments and thermocycling. MATERIALS AND METHODS. Rectangular 3D-printed denture base resin (Cosmos Denture) specimens (N = 130) were thermocycled (5,000 cycles, 5℃ and 55℃) before and after the different repair techniques (n = 10 per group) using an autopolymerized acrylic resin (Jet, J) or a hard relining resin (Soft Confort, SC), and different surface treatments: Jet resin monomer for 180 s (MMA), blasting with aluminum oxide (JAT) or erbium: yttrium-aluminum-garnet laser (L). The control group were intact specimens. A three-point flexural strength test was performed, and data (MPa) were analyzed by ANOVA and Games-Howell post hoc test (α = 0.05). Each failure was observed and classified through stereomicroscope images and the surface treatments were viewed by scanning electron microscope (SEM). RESULTS. Control group showed the highest mean of flexural strength, statistically different from the other groups (P < .001), followed by MMA+J group. The groups with L treatment were statistically similar to the MMA groups (P > .05). The JAT+J group was better than the SC and JAT+SC groups (P < .05), but similar to the other groups (P > .05). Adhesive failures were most observed in JAT groups, especially when repaired with SC. The SEM images showed surface changes for all treatments, except JAT alone. CONCLUSION. Denture bases fabricated with 3D-printed resin should be preferably repaired with MMA+J. SC and JAT+SC showed the worst results. Blasting impaired the adhesion of the SC resin.

• Medical Lasers
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• 제10권2호
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• pp.96-105
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• 2021

Background and Objectives Skin aging is reportedly associated with regulation in collagen and elastin synthesis. This study investigated the potential of combining light-emitting diode (LED) treatments using a 630-nm and 850-nm LED with simultaneous microcurrent application. Materials and Methods The dorsal skin of female pigs was treated with a home-use device. We examined the treatment effects using photography, thermocamera, microscopic pathology, and histological examination to determine the mechanism of action, efficacy, and safety of the procedure. A histological observation was performed using hematoxylin and eosin, Masson's trichrome, Victoria blue, and immunohistochemical staining. We also used the Sircol soluble collagen and elastin assay kit to measure the amounts of collagen and elastin in the porcine back skin tissue after 2 and 6 weeks. Results Evaluation by visual inspection and devices showed no skin damage or heat-induced injury at the treatment site. Histological staining revealed that accurate treatment of the targeted dermis layer effectively enhanced collagen and elastin deposition. Collagen type I, a protein defined by immunohistochemical staining, was overexpressed in the early stages of weeks 2 and 6. Combined therapy findings showed the superior capability of the 630-nm and 850-nm LED procedures to induce collagen; in contrast, elastin induction was more pronounced after microcurrent treatments. Conclusion The home-use LED device, comprising a combination of 630-nm and 850-nm LEDs and microcurrent, is safe and can be used as an adjunctive treatment for self-administered facial rejuvenation.

• Medical Lasers
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• 제10권4호
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• pp.220-228
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• 2021

Background and Objectives In designing a resistance exercise program, intensity, rest, and exercise volume are important. Many studies have been conducted to find the most suitable resistance exercise program incorporating the above, and in particular, many prior studies have been conducted on intensity. This study attempted to determine the effective volume of exercise by analyzing the number of repetitions performed at intensities of 65% one-repetition maximum (1RM) and 75% 1RM during the bench press exercise, and the electromyography (EMG) response of the agonist muscle. Materials and Methods Eight males in their 20s were selected as study subjects and they performed five sets of bench presses at two levels of intensity (65% 1RM, 75% 1RM). The following results were obtained by measuring the number of repetitions and the EMG response according to the exercise intensity and sets during the workout. Results First, the number of repetitions showed a sharp drop from the first set to the third set at 65% 1RM intensity and showed no change in the fourth and fifth sets. At 75% 1RM intensity, the intensity of hypertrophy showed a gradual decrease from the first set to the fifth set. Second, at 75% 1RM exercise intensity, the pectoralis major, anterior deltoid and triceps brachii showed high muscle activity, and the activity of the anterior deltoid continued to increase from the first set to the fourth set at 65% 1RM intensity, and from the first set to the fifth set at 75% 1RM. Conclusion It was found that during the bench press exercise, three minutes of rest at 75% 1RM intensity, five sets of five sets, one minute rest at 65% 1RM intensity, and three sets of the exercise were effective.

• Medical Lasers
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• 제10권1호
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• pp.22-30
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• 2021

Background and Objectives Ocular alkali burns cause severe damage to the ocular tissues and vision loss. Solcoseryl is a standardized calf blood extract that normalizes the metabolic disturbance and aids in maintaining the chemical and hormonal balance and has been used to treat burns in various tissues. This study examined the effects of Solcoseryl on a rat corneal alkali burn model. Materials and Methods Twenty rats were assigned randomly to four equal groups, including alkali burn, hyaluronic acid, Solcoseryl eyedrop, and Solcoseryl gel. A corneal alkali burn was induced by a NaOH-soaked paper disc. The treatments were given twice a day, every day. The wound area was measured after 24 and 48 hours, and the degree of neovascularization and corneal opacity were scored every week. The rats were sacrificed after three weeks for immunohistochemistry (IHC) to compare the level of inflammatory cytokines, IL-1β, IL-6, and TNF-α. The thickness of the retinal layers was compared to observe any changes in the retina. Results The use of Solcoseryl on corneal alkali burn accelerated wound healing with less neovascularization, greater opacity, and less cataract. IHC showed that the inflammation of the cornea was controlled by both the hyaluronic acid and Solcoseryl treatments. On the other hand, the inflammation had spread to the retina. When the dosage forms were compared, eyedrops were more effective on corneal inflammation, while the gel-type had a greater effect on retinal inflammation. Conclusion Solcoseryl was effective in accelerating the wound healing rate on a corneal alkali burn but could not prevent the spread of inflammation from the cornea to the retina. Eyedrops were more effective on inflammation in the cornea, and the gel was more effective in the retina.

• Medical Lasers
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• 제9권1호
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• pp.39-43
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• 2020

Background and Objectives Breast reconstruction has the advantage of reducing the loss of the body image of patients after mastectomy surgery, and also improving the quality of the social and sexual life of breast cancer patients. However, in surprising and unfortunate number of patients, acute postoperative pain persists beyond the normal course of postsurgical recovery. We set out to investigate the effect of local dynamical micro-massage (LDM) treatment for achieving pain relief and reducing other postoperative complications. Materials and Methods We performed a retrospective analysis on 58 patients who underwent LDM treatment for postoperative pain management at Soonchunhyang University Bucheon Hospital between February 2017 and June 2019. Those patients who complained of persistent postoperative pain, which was uncontrollable with medication, were treated with LDM. The degree of pain and discomfort with contracture were recorded using numerical rating scale (NRS) scoring system with numbers from 0 to 10 ('none' to 'worst'). Results The median NRS score of pain was reduced by 62.3% from the start to the end of LDM treatment (p<0.001). Further, the NRS score of discomfort with contracture was reduced 66.0% (p<0.001). There was no complication related to the LDM treatment. Conclusion Dual-frequency ultrasound LDM can be an effective therapeutic option for persisting pain after breast reconstruction surgery. It was also effective in improvement of discomfort with contracture and erythema of the surgical wound.

• 한국산학기술학회논문지
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• 제22권5호
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• pp.199-206
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• 2021

본 논문은 잠수함 공격잠망경(Attack periscope) 보호를 위한 보호구조물 설치 타당성 및 신뢰성 검증 방안에 대해 서술하고 있다. 공격잠망경은 잠망경 심도 및 수상 항해 시 대수상 및 대공 표적을 은밀하게 시각적으로 확인하기 위한 핵심 탑재 장비이다. 관측장치 및 거리측정장치를 통해 획득된 표적 정보를 전투체계에 제공하며, 대수상 및 대공탐색하여 자함의 위협 수준 판단과 표적의 영상, 거리를 포함한 위치 정보를 제공한다. OOO급 잠수함 성능개량 시 공격 잠망경을 신규 장비로 교체함에 따라 마스트 길이가 증가하였고, 증가된 마스트 길이만큼 외부로 노출됨에 따라 항해 시 어망, 그물과 같은 해상 부유물에 의한 장비 손상 발생 가능성이 커졌다. 따라서 함교에 공격잠망경 보호구조물을 설치하여 장비 운용성능을 향상시켰으며, CFD 해석 및 실제 해상에서의 수중방사소음 측정을 통해 보호구조물 설치 타당성 및 신뢰성 검증을 수행하였다. 본 연구를 통하여 향후 공격잠망경 신규 장비 교체 시 건전성 확보를 위한 참고자료로 활용될 수 있을 것으로 기대된다.

• 항공우주시스템공학회지
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• 제15권3호
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• pp.57-64
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• 2021

본 연구에서는 KV의 유도조종오차를 최소화하여 직격요격 성능을 확보하고자 DACS 구동장치에 대한 위치정확도 점검방안을 제안하였다. DACS 구동장치의 정확도 성능은 탄도미사일 요격에 중요한 성능 중 하나이다. DACS 구동장치의 정확도 성능을 검증하기 위해 위치정확도란 점검 항목을 도출하였고, 이에 대한 점검시스템 설계 및 점검절차를 기술하였다. 핀틀 위치정확도 점검시스템은 레이저 변위센서를 이용하여 핀틀의 구동변위를 외부 계측할 수 있도록 구성하였고, 외부 계측한 데이터는 실시간으로 구동명령 및 피드백 데이터와 비교분석할 수 있도록 설계하였다. 본 논문에서 제안하는 위치정확도 점검시스템은 DACS 조립체 뿐만 아니라 유도탄 조립체 단위에서도 점검이 가능하도록 설계하였다. 설계된 점검시스템을 이용하여 핀틀의 위치정확도 점검을 수행하였고, 점검 결과를 분석하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제25권4호
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• pp.355-363
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• 2021

Dynamic changes in adipose tissue blood flow (ATBF) with nutritional status play a role in the regulation of metabolic and endocrine functions. Activation of the sympathetic nervous system via β-adrenergic receptors (β-AR) contributes to the control of postprandial enhancement of ATBF. Herein, we sought to identify the role of each β-AR subtype in the regulation of ATBF in mice. We monitored the changes in visceral epididymal ATBF (VAT BF), induced by local infusion of dobutamine, salbutamol, and CL316,243 (a selective β1-, β2-, and β3-AR agonist, respectively) into VAT of lean CD-1 mice and global adipose triglyceride lipase (ATGL) knockout (KO) mice, using laser Doppler flowmetry. Administration of CL316,243, known to promote lipolysis in adipocytes, significantly increased VAT BF of CD-1 mice to a greater extent compared to that of the vehicle, whereas administration of dobutamine or salbutamol did not produce significant differences in VAT BF. The increase in VAT BF induced by β3-AR stimulation disappeared in ATGL KO mice as opposed to their wild-type (WT) littermates, implying a role of ATGL-mediated lipolysis in the regulation of VAT BF. Different vascular reactivities occurred despite no significant differences in vessel density and adiposity between the groups. Additionally, the expression levels of the angiogenesis-related genes were significantly higher in VAT of ATGL KO mice than in that of WT, implicating an association of ATBF responsiveness with angiogenic activity in VAT. Our findings suggest a potential role of β3-AR signaling in the regulation of VAT BF via ATGL-mediated lipolysis in mice.

• 한국광학회지
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• 제32권6호
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• pp.306-313
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• 2021

버퍼가스와 세슘 증기가 혼합된 광 증폭 시스템을 구성하고 세슘 용기의 온도 및 빔 직경의 변화에 따른 광 증폭 특성을 조사하였다. 광 증폭인자 및 추출 효율 등 광 증폭기 특성이 세슘 용기의 온도 및 빔 직경에 따라 크게 변하는 것을 확인하였는데, 90 ℃의 세슘 용기온도에서 200 ㎛ 직경을 가진 펌프(500 mW) 및 씨앗 광(10 mW)이 입사하였을 때 최대 56%의 광 추출효율을 얻을 수 있었다. 또한, 전산 모사를 통하여 계산한 광 증폭 특성이 실험으로부터 얻은 결과와 합리적으로 일치하는 것을 확인하였다.

• 대한의용생체공학회:의공학회지
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• 제43권2호
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• pp.116-123
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• 2022

This study analyzes the Mechanical properties of a medical bone plate by 3D printing. With the recent development of 3D printing technology, it is being applied in various fields. In particular, in the medical field, the use of 3D printing technology, which was limited to the existing orthosis and surgical simulation, has recently been used to replacement bones lost due to orthopedic implants using metal 3D printing. The field of application is increasing, such as replacement. However, due to the manufacturing characteristics of 3D printing, micro pores are generated inside the metal printing output, and it is necessary to reduce the pores and the loss of mechanical properties through post-processing such as heat treatment. Accordingly, the purpose of this study is to analyze the change in mechanical performance characteristics of medical metal plates manufactured by metal 3D printing under various conditions and to find efficient metal printing results. The specimen to be used in the experiment is a metal plate for trauma fixation applied to the human phalanx, and it was manufactured using the 'DMP Flex 100(3D Systems, USA), a metal 3D printer of DMLS (Direct Metal Laser Sintering) method. It was manufactured using the PBF(Powder Bed Fusion) method using Ti6Al4V ELI powder material.