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Long-term clinical study and multiscale analysis of in vivo biodegradation mechanism of Mg alloy
Lee, Jee-Wook,Han, Hyung-Seop,Han, Kyeong-Jin,Park, Jimin,Jeon, Hojeong,Ok, Myoung-Ryul,Seok, Hyun-Kwang,Ahn, Jae-Pyoung,Lee, Kyung Eun,Lee, Dong-Ho,Yang, Seok-Jo,Cho, Sung-Youn,Cha, Pil-Ryung,Kwon, H National Academy of Sciences 2016 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.113 No.3
<P>There has been a tremendous amount of research in the past decade to optimize the mechanical properties and degradation behavior of the biodegradable Mg alloy for orthopedic implant. Despite the feasibility of degrading implant, the lack of fundamental understanding about biocompatibility and underlying bone formation mechanism is currently limiting the use in clinical applications. Herein, we report the result of long-term clinical study and systematic investigation of bone formation mechanism of the biodegradable Mg-5wt% Ca-1wt% Zn alloy implant through simultaneous observation of changes in element composition and crystallinity within degrading interface at hierarchical levels. Controlled degradation of Mg-5wt% Ca-1wt% Zn alloy results in the formation of biomimicking calcification matrix at the degrading interface to initiate the bone formation process. This process facilitates early bone healing and allows the complete replacement of biodegradable Mg implant by the new bone within 1 y of implantation, as demonstrated in 53 cases of successful long-term clinical study.</P>
Hojeong Lee,Dong Woon Kim,Ji Hyeon Joo,Yongkan Ki,Wontaek Kim,Dahl Park,Jiho Nam,Dong Hyeon Kim,Hosang Jeon Korean Society of Medical Physics 2022 의학물리 Vol.33 No.4
Purpose: Radiotherapy after bladder filling protocol (BFP) is known to enhance treatment quality and reduce side effects in prostate cancer, a common male solid cancer globally. However, due to the need to hold back urine during treatment, patients frequently complain of discomfort, and treatment is frequently suspended when patients urinate during treatment and urine penetrates the treatment device, causing malfunction. Therefore, the effect of minimizing treatment time when partial-arc volumetric modulated arc therapy (VMAT) was used instead of full-arc was assessed in this study. Methods: A total of 70 plans were created in 10 patients using 7 different arc sizes, and the treatment time for each plan was calculated. Results: Reduced arc size by half resulted in a 54.4% decrease in mean treatment duration, with a proportional tendency observed. Furthermore, the effect of VMAT arc size reduction on target dose homogeneity was significantly limited, and the effect on surrounding organs at risk (OAR) was negligible. It should be noted, however, that when the arc size decreases by >40%, the dose increases in the area without OAR around the target. Conclusions: The results of this study demonstrated that partial-arc VMAT for enhancing treatment convenience and efficacy of prostate cancer patients undergoing BFP can achieve a considerable reduction in treatment time while preserving treatment quality, and it is expected to be useful for partial-arc VMAT plan design and implementation in practice.
P181 Secondary cutaneous DLBCL has a higher IPI score and worse prognosis than DLBCL, leg type
( Hojeong Shin ),( Woojin Lee ),( Kwanghee Won ),( Chonghyun Won ),( Sungeun Chang ),( Jeeho Choi ),( Keechan Moon ),( Chansik Park ),( Jooryung Huh ),( Cheolwon Suh ),( Miwoo Lee ) 대한피부과학회 2016 대한피부과학회 학술발표대회집 Vol.68 No.2
<div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div> Background: Differences in skin lesions and survival data for cutaneous diffuse large B-cell lymphoma (DLBCL) depending on primary tumor site are currently unknown. Objectives: we aimed to analyze the clinical features of skin lesions and survival outcomes of cutaneous DLBCL according to the primary tumor site. Methods: Forty-seven patients with cutaneous DLBCL were classified as primary cutaneous DLBCL or cutaneous DLBCL secondary to primary disease. Clinical features, survival outcomes, and prognostic factors were analyzed using patient medical records. Survival outcomes were analyzed using the Kaplan.Meier method and compared using the log-rank test. Results: Although skin lesion characteristics did not significantly differ between groups, secondary cutaneous DLBCL more commonly presented disseminated skin lesions that involved multiple anatomical sites. Primary cutaneous DLBCL demonstrated a less aggressive clinical course and better survival outcomes than secondary cutaneous DLBCL. Disseminated skin lesions and a location on the leg significantly affected the prognosis of primary cutaneous DLBCL. The multiplicity of skin lesions and time point of cutaneous involvement were associated with prognosis in secondary cutaneous DLBCL. Conclusion: Although the clinical features of skin lesions were similar regardless of subgroup, survival outcomes and prognostic factors differed depending on the primary tumor site of cutaneous DLBCL.
Treatment of acne scars with autologous fibroblast injection
( Hojeong Shin ),( Yejin Lee ),( Woojin Lee ),( Sungeun Chang ),( Miwoo Lee ),( Jeeho Choi ),( Chonghyun Won ) 대한피부과학회 2017 대한피부과학회 학술발표대회집 Vol.69 No.2
Background: Acne scars cause cosmetically and psychologically devastating effect. Autologous fibroblast injections increase dermal collagen formation result in dermal remodeling without serious adverse events. Objectives: We evaluated efficacy and safety of autologous fibroblast injections for treatment of acne scars. Methods: Five patients with acne scar included and fibroblast were cultured from postauricualr fold skin for 8 weeks. Cultured autologous fibroblasts(20million/mL) or placebo were injected intradermaly on both cheek for three times at 2 week intervals. Primary end point was a 2-point shift in at least one treated area using a standardized 7-point photoguide. Secondary end point was improvement of ECCA grading scale, physician improvement scale, subject acne scar assessment. Results: Three patients received autologous fibroblast injection and two patients received placebo injection. All three patients responded to the treatment with a 2-point shift in at least one treated area. ECOG grading score was improved by 48% in treatment group and 5% in control group. Average of physician improvement scale was 2.7 for treatment group and 0 for control group. In treatment group, 2 patients were satisfied, and 1 patients was very satisfied. Autologous fibroblast injections were well tolerated, without permanent adverse effect. Conclusion: Our results suggest that autologous fibroblast injections could be another option for treatment of acne scars.
( Hojeong Shin ),( Woojin Lee ),( Yejin Lee ),( Chonghyun Won ),( Sungeun Chang ),( Jeeho Choi ),( Miwoo Lee ) 대한피부과학회 2017 대한피부과학회 학술발표대회집 Vol.69 No.2
Background: Interactions between immune cells and tumor cells play an important role in tumor progression. Objectives: We evaluated patterns of tumor infiltrating lymphocytes (TILs) and programmed death-1 (PD-1) expression in acral and non-acral cutaneous melanoma, and determined their effects on clinicopathological characteristics and biologic responses. Methods: We identified 122 cases of cutaneous melanoma, of which 39 were cases of non-nail unit acral melanoma, 35 were cases of nail unit melanoma and 48 were cases of non-acral melanoma. Clinicopathological features and survival outcomes were analyzed according to the scores for TILs and PD-1 expression in intra- and peritumoral compartments. Results: The frequency of intratumoral TILs and PD-1 expression were lower in nail unit melanoma than in the other two subtypes. The density of peritumoral PD-1 was significantly higher in non-nail unit acral melanoma. In nail unit melanoma and non-acral melanoma, a low density of intratumoral TILs and PD-1 was associated with a deeper Breslow thickness and the presence of a vertical growth phase. In non-nail unit acral melanoma, a high density of peritumoral TILs and PD-1 was associated with a shallower Breslow thickness and less frequent extracutaneous dissemination. Conclusion: This study suggests that the effects of PD-1+TILs on biological activity differ according to the clinical subtypes of cutaneous melanoma.
Light-triggered shell formation on CdSe quantum dots in glasses
Lee Hojeong,권영건,허종 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.1
Combination of heat treatment and continuous-wave (CW) laser irradiation at wavelength λ = 532 nm was designed to precipi- tate quantum dots (QDs) that had Cd-rich core and Zn-rich shell inside a glass matrix. Soda-alumino-silicate glass contain- ing Cd, Zn and Se was heat-treated at 550 °C for 3 h. This glass has a strong absorption band at λ = 513.6 (± 52.7) nm and its photoluminescence spectrum has a strong defect emission centered at λ = ~ 609 nm in addition to the intrinsic CdSe QD emission at λ = ~ 546 nm. Irradiation by a CW laser beam with intensity of 14 W/cm 2 for 1 min resulted in a large decrease of the intensity of defect emission. After the initial heat treatment, Cd-rich QDs with an average diameter of ~ 3.15 nm and composition of Cd 0.71 Zn 0.29 Se precipitated in the glass. Upon subsequent laser irradiation, a Zn-rich shell of Cd 0.23 Zn 0.77 Se formed on the surface of Cd-rich cores. Temperature of the glass during this laser irradiation, estimated using Nd 3+ optical thermometry was ~ 637 °C. Cd-rich QD has a band-gap that matches the energy of the laser beam, and therefore converts the photon energy to thermal energy. This thermal energy raises the temperature of the glass and facilitates the diff usion of ions to form Zn-rich shells.
Jeon, Hojeong,Lee, Yongku,Jin, Songwan,Koo, Sangmo,Lee, Chang-Soo,Yoo, Jung Yul Springer US 2009 BIOMEDICAL MICRODEVICES Vol.11 No.5
<P>A microfluidic device to quantify bacterial chemotaxis has been proposed, which generates a linear concentration gradient of chemoattractant in the main channel only by convective and molecular diffusion, and which enables the bacteria to enter the main channel in a single file by hydrodynamic focusing technique. The trajectory of each bacterium in response to the concentration gradient of chemoattractant is photographed by a CCD camera and its velocity is acquired by a simple PTV (Particle Tracking Velocimetry) algorithm. An advantage of this assay is to measure the velocity of a single bacterium and to quantify the degree of chemotaxis by analyzing the frequency of velocities concurrently. Thus, the parameter characterizing the motility of wild-type <I>Escherichia coli</I> strain RP437 in response to various concentration gradients of L-aspartate is obtained in such a manner that the degree of bacterial chemotaxis is quantified on the basis of a newly proposed Migration Index.</P>
필로티 구조물에서 자동차 화재시 바닥 구조물의 거동 및 내화성능 비교
이호정(HoJeong Lee),박지혜(JiHye Park),최인락(InRak Choi),민정기(JeongKi Min),최성모(SungMo Choi) 한국화재소방학회 2022 한국화재소방학회 학술대회 논문집 Vol.2022 No.추계
도심형 생활주택의 필로티 구조는 건물의 주차장으로 주로 사용되며, 다수의 차량이 주차되어있어 화재발생시 연소확대의 위험성이 있다. 본 연구에서 필로티 구조 공간에서 자동차화재가 발생할 때 화재양상은 수평보다 수직이 빠르기 때문에, 바닥 구조체의 내화성능을 확인하기 위해 유한요소해석 프로그램인 SAFIR를 사용하여 해석을 진행하였다. KS F 2257-1 기준의 표준화재 곡선과 필로티 구조 공간에서 주차공간과 유사한 형상의 2.9m×5.4m 프레임에 자동차의 화재상황을 구현하여 얻어진 화재곡선을 적용하여 화재시 필로티 바닥구조물의 거동을 확인하였다. 도심형 생활주택의 바닥하중을 내화설계 하중조합에 적용하였다. 실험조건과 같은 구조체의 경계조건을 입력하였다. 유한요소해석을 통해 구조물 해석 진행하여 슬래브의 처짐을 비교하고, 내화성능 판정식을 통해 내화성능시간을 확인하여 건물의 안정성을 확인하고자 한다.