• Biomolecules & Therapeutics
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• 제23권4호
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• pp.357-366
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• 2015

Isorhamnetin (3-methylquercetin) is a flavonoid derived from the fruits of certain medicinal plants. This study investigated the photoprotective properties of isorhamnetin against cell damage and apoptosis resulting from excessive ultraviolet (UV) B exposure in human HaCaT keratinocytes. Isorhamnetin eliminated UVB-induced intracellular reactive oxygen species (ROS) and attenuated the oxidative modification of DNA, lipids, and proteins in response to UVB radiation. Moreover, isorhamnetin repressed UVB-facilitated programmed cell death in the keratinocytes, as evidenced by a reduction in apoptotic body formation, and nuclear fragmentation. Additionally, isorhamnetin suppressed the ability of UVB light to trigger mitochondrial dysfunction. Taken together, these results indicate that isorhamnetin has the potential to protect human keratinocytes against UVB-induced cell damage and death.

• 한국광학회지
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• 제19권4호
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• pp.249-254
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• 2008

새 구조의 액정 엑스선 감지기를 만들었다. 이것은 액정판을 만들고 유리판을 얇게 식각한 다음, 그 유리판 위에 반사막과 광전도층을 연속하여 입힌 구조이다. 새 구조의 액정엑스선 감지기는 공정의 안정성, 대면적화, 감도 등에서 이미 상품화된 엑스선 감지기와도 충분히 경쟁할 수 있으며, 따라서 성공적으로 상용화 할 수 있음을 확인했다.

• Biomolecules & Therapeutics
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• 제29권1호
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• pp.90-97
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• 2021

Ultraviolet B (UVB) radiation causes DNA base modifications. One of these changes leads to the generation of 8-oxoguanine (8-oxoG) due to oxidative stress. In human skin, this modification may induce sunburn, inflammation, and aging and may ultimately result in cancer. We investigated whether phloroglucinol (1,3,5-trihydroxybenzene), by enhancing the expression and activity of 8-oxoG DNA glycosylase 1 (Ogg1), had an effect on the capacity of UVB-exposed human HaCaT keratinocytes to repair oxidative DNA damage. Here, the effects of phloroglucinol were investigated using a luciferase activity assay, reverse transcription-polymerase chain reactions, western blot analysis, and a chromatin immunoprecipitation assay. Phloroglucinol restored Ogg1 activity and decreased the formation of 8-oxoG in UVB-exposed cells. Moreover, phloroglucinol increased Ogg1 transcription and protein expression, counteracting the UVB-induced reduction in Ogg1 levels. Phloroglucinol also enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) as well as Nrf2 binding to an antioxidant response element located in the Ogg1 gene promoter. UVB exposure inhibited the phosphorylation of protein kinase B (PKB or Akt) and extracellular signal-regulated kinase (Erk), two major enzymes involved in cell protection against oxidative stress, regulating the activity of Nrf2. Akt and Erk phosphorylation was restored by phloroglucinol in the UVB-exposed keratinocytes. These results indicated that phloroglucinol attenuated UVB-induced 8-oxoG formation in keratinocytes via an Akt/Erk-dependent, Nrf2/Ogg1-mediated signaling pathway.

• Ocean Systems Engineering
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• 제10권4호
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• pp.399-414
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• 2020

A floating bridge is an innovative solution for deep-water and long-distance crossing. This paper presents a curved floating bridge's dynamic behaviors under the wind, wave, and current loads. Since the present curved bridge need not have mooring lines, its deep-water application can be more straightforward than conventional straight floating bridges with mooring lines. We solve the coupled interaction among the bridge girders, pontoons, and columns in the time-domain and to consider various load combinations to evaluate each force's contribution to overall dynamic responses. Discrete pontoons are uniformly spaced, and the pontoon's hydrodynamic coefficients and excitation forces are computed in the frequency domain by using the potential-theory-based 3D diffraction/radiation program. In the successive time-domain simulation, the Cummins equation is used for solving the pontoon's dynamics, and the bridge girders and columns are modeled by the beam theory and finite element formulation. Then, all the components are fully coupled to solve the fully-coupled equation of motion. Subsequently, the wet natural frequencies for various bending modes are identified. Then, the time histories and spectra of the girder's dynamic responses are presented and systematically analyzed. The second-order difference-frequency wave force and slowly-varying wind force may significantly affect the girder's lateral responses through resonance if the bridge's lateral bending stiffness is not sufficient. On the other hand, the first-order wave-frequency forces play a crucial role in the vertical responses.

• 한국임상약학회지
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• 제30권4호
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• pp.234-242
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• 2020

Background: Bevacizumab-induced proteinuria is known to occur when vascular endothelial cell receptors are blocked, which leads to decreased protein filtration. Although several studies have analyzed the correlation between therapeutic effect of bevacizumab and proteinuria, no conclusion has been established. Methods: In this retrospective study, colorectal cancer patients who received bevacizumab and urinary protein check from January 2015 to December 2016, were included. The incidence of proteinuria and the grade according to Common Terminology Criteria for Adverse Events (CTCAE) 4.0 were evaluated after bevacizumab administration. The primary objective was to correlate proteinuria with overall response rate (ORR) and time to progression (TTP). Primary lesion, metastasized organs, surgery or radiation therapy, chemotherapy were investigated for analysis of risk factors for proteinuria development. Results: A total of 149 patients included in the analysis. Proteinuria occurred 19.5% (n=29) in the study patients; 20 in grade 1, 7 in grade 2, and 2 in grade 3. ORR was 55.2% in the proteinuria group and 51.7% in the non-proteinuria group. There was no difference between two groups (p=0.89). The TTP through the survival curve was similar in both groups (10 months, p=0.97). The risk of proteinuria was high in patients who had liver metastasis (p=0.02) and no surgery (p=0.01). Conclusions: These result indicates that bevacizumab-induced proteinuria expression was not correlated with the therapeutic effect on patients with colorectal cancer. Further analysis is required to find out the correlation between proteinuria and therapeutic effects. The risk of proteinuria was increased from patients who had liver metastasis, and no surgery.

• 한국의학물리학회지:의학물리
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• 제31권4호
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• pp.135-144
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• 2020

Purpose: Gafchromic films for proton dosimetry are dependent on linear energy transfers (LETs), resulting in dose underestimation for high LETs. Despite efforts to resolve this problem for single-energy beams, there remains a need to do so for multi-energy beams. Here, a bimolecular reaction model was applied to correct the under-response of spread-out Bragg peaks (SOBPs). Methods: For depth-dose measurements, a Gafchromic EBT3 film was positioned in water perpendicular to the ground. The gantry was rotated at 15° to avoid disturbances in the beam path. A set of films was exposed to a uniformly scanned 112-MeV pristine proton beam with six different dose intensities, ranging from 0.373 to 4.865 Gy, at a 2-cm depth. Another set of films was irradiated with SOBPs with maximum energies of 110, 150, and 190 MeV having modulation widths of 5.39, 4.27, and 5.34 cm, respectively. The correction function was obtained using 150.8-MeV SOBP data. The LET of the SOBP was then analytically calculated. Finally, the model was validated for a uniform cubic dose distribution and compared with multilayered ionization chamber data. Results: The dose error in the plateau region was within 4% when normalized with the maximum dose. The discrepancy of the range was <1 mm for all measured energies. The highest errors occurred at 70 MeV owing to the steep gradient with the narrowest Bragg peak. Conclusions: With bimolecular model-based correction, an EBT3 film can be used to accurately verify the depth dose of scanned proton beams and could potentially be used to evaluate the depth-dose distribution for patient plans.

• 한국항공우주학회지
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• 제50권2호
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• pp.119-125
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• 2022

본 논문에서는 500kg급 중형위성에 탑재를 목표로 개발한 C-밴드 영상 레이다용 파형발생수신모듈의 설계, 제작 및 시험 결과를 제시한다. 파형발생수신모듈은 약 500km의 고도에서 해상도 10m 기준 120km의 관측 폭을 만족할 수 있도록 50MHz 대역의 2개 주파수를 동시 운용하는 이중주파수 스캔 방식을 적용할 수 있도록 설계하였다. 제작된 파형발생수신모듈은 우주환경을 고려하여 방사성 내성이 고려된 RTG4 FPGA를 적용하였으며, 병렬 직접합성방식(PDDS)을 적용하여 메모리 맵 방식 대비 작은 메모리 용량으로 첩 신호를 생성할 수 있도록 구현하였다. 시험결과 주파수 순도가 높은 첩 파형을 안정적으로 생성하였으며, 수신 신호에 대해 디지털 하향 변환 후 확인 결과 목표한 IRF (Impulse Response Function) 성능을 확인할 수 있었다.

• 대한두경부종양학회지
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• 제38권2호
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• pp.7-13
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• 2022

Human papillomavirus (HPV) is a causative agent for a subset of oropharyngeal cancer (OPC). The current standard of care (SOC) for locally advanced OPC is 70 Gy definitive radiotherapy (RT) concurrent with cisplatin, which entails significant proportions of acute and late grade 3 or higher toxicities. Accordingly, discovery of favorable prognosis of HPV-related OPC has led to enthusiasm to attenuate subspecialties therapy in multidisciplinary treatment. Diverse deintensification strategies were investigated in multiple phase 2 trials with an assumption that attenuated treatments result in comparable oncologic outcome and less toxicities compared with SOC. Several trials on chemotherapy deintensification revealed that concomitant administration of cisplatin is not to be omitted or substituted for cetuximab without compromising progression-free survival or local control. A transoral robotic surgery (TORS) is investigated as alternative local treatment, but TORS plus SOC or mild deintensified adjuvant RT showed similar toxicities and inferior oncologic outcomes compared with SOC definitive RT or moderately deintensified RT. However, it has been reported that TORS plus deintensified 30-36 Gy adjuvant RT results in excellent outcome and less late toxicity compared with SOC adjuvant RT. Several phase 2 trials reported apparently equivalent progression-free survival and local control and similar adverse effects with moderately deintensified 60 Gy RT compared with SOC 70 Gy RT. Further dose reduction below 60 Gy has been investigated using biology-directed approaches, which use response to induction chemotherapy or metabolic images to triage HPV-positive OPC for deintensified RT. In summary, these trials provide valuable insights for future directions. Available evidence consistently showed that moderately deintensified RT is effective and safe for HPV-positive OPC in both definitive and adjuvant settings. Concurrent cisplatin remains an essential component without which progression-free survival is significantly compromised for advanced HPV-positive OPC. A simple incorporation of TORS to SOC may be detrimental for oncologic outcome without anticipated toxicity reduction. Given the lack of level 1 evidence, it is prudent to curb an unjustified deviation from the current SOC and limit any deintensified strategies to clinical trials and adhere to the current SOC.

• Archives of Plastic Surgery
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• 제50권4호
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• pp.361-369
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• 2023

The latissimus dorsi (LD) flap is a reliable option for breast reconstruction. This is particularly true in patients with contraindications to abdominally based autologous breast reconstruction. A systematic review of patient satisfaction and health related quality of life following LD breast reconstruction using the BREAST-Q survey was conducted. The scope of the review was to determine the degree of patient satisfaction following the procedure and to examine how patient satisfaction from the pedicled LD flap compares to other breast reconstructive procedures. A literature search on BREAST-Q in LD flap reconstruction was performed. Only articles written in English and in published peer-reviewed journals were included. Studies with less than 20 patients in their sample and those with a follow-up period of less than 1 year were excluded. Five articles representing 331 patients were reviewed, including one case-control study and four retrospective cohort studies. Level of evidence was either III (4) or IV (1). The average age was 53 with average body mass index of 25. Most reconstructions were delayed (67%) and unilateral (88%), and most patients required radiation (79%). The average length of follow-up was 36 months, and the response rate was 75%. Overall, patients who underwent LD flap reconstruction reported favorable outcomes in satisfaction domains and quality of life domains with few complications. A meta-analysis also demonstrated higher satisfaction in LD flap without implants compared with LD flap with implants. Patient-reported outcomes following LD breast reconstruction compare favorably with other techniques of breast reconstruction.

• Korean Journal of Radiology
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• 제23권4호
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• pp.402-412
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• 2022

Objective: To evaluate the image quality and lesion detectability of lower-dose CT (LDCT) of the abdomen and pelvis obtained using a deep learning image reconstruction (DLIR) algorithm compared with those of standard-dose CT (SDCT) images. Materials and Methods: This retrospective study included 123 patients (mean age ± standard deviation, 63 ± 11 years; male:female, 70:53) who underwent contrast-enhanced abdominopelvic LDCT between May and August 2020 and had prior SDCT obtained using the same CT scanner within a year. LDCT images were reconstructed with hybrid iterative reconstruction (h-IR) and DLIR at medium and high strengths (DLIR-M and DLIR-H), while SDCT images were reconstructed with h-IR. For quantitative image quality analysis, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured in the liver, muscle, and aorta. Among the three different LDCT reconstruction algorithms, the one showing the smallest difference in quantitative parameters from those of SDCT images was selected for qualitative image quality analysis and lesion detectability evaluation. For qualitative analysis, overall image quality, image noise, image sharpness, image texture, and lesion conspicuity were graded using a 5-point scale by two radiologists. Observer performance in focal liver lesion detection was evaluated by comparing the jackknife free-response receiver operating characteristic figures-of-merit (FOM). Results: LDCT (35.1% dose reduction compared with SDCT) images obtained using DLIR-M showed similar quantitative measures to those of SDCT with h-IR images. All qualitative parameters of LDCT with DLIR-M images but image texture were similar to or significantly better than those of SDCT with h-IR images. The lesion detectability on LDCT with DLIR-M images was not significantly different from that of SDCT with h-IR images (reader-averaged FOM, 0.887 vs. 0.874, respectively; p = 0.581). Conclusion: Overall image quality and detectability of focal liver lesions is preserved in contrast-enhanced abdominopelvic LDCT obtained with DLIR-M relative to those in SDCT with h-IR.