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Light Scattering Study of Glass Transition Temperatures of Glucose-Water Mixtures
서정아,오지영,김형국,황윤회 부산대학교 유전체물성연구소 2004 유전체 논문집 Vol.3 No.
We studied glass transition temperatures of glucose-water mixtures by using Brillouin light scattering. We fitted the polarized components of the Brillouin spectra measured by backscattering geometry to simple Lorentzian form and estimated the glass transition temperature from the slope of the temperature-dependent Brillouin peak shift.
Yoon, Jiyoung,Cho, Byeong-Hoon,Bae, Jihyun,Choi, Yonghoon The Korean Academy of Conservative Dentistry 2018 Restorative Dentistry & Endodontics Vol.43 No.2
Objectives: Understanding the reason for an unsuccessful non-surgical endodontic treatment outcome, as well as the complex anatomy of the root canal system, is very important. This study examined the cross-sectional root canal structure of mandibular first molars confirmed to have failed non-surgical root canal treatment using digital images obtained during intentional replantation surgery, as well as the causative factors of the failed conventional endodontic treatments. Materials and Methods: This study evaluated 115 mandibular first molars. Digital photographic images of the resected surface were taken at the apical 3 mm level and examined. The discolored dentin area around the root canal was investigated by measuring the total surface area, the treated areas as determined by the endodontic filling material, and the discolored dentin area. Results: Forty 2-rooted teeth showed discolored root dentin in both the mesial and distal roots. Compared to the original filled area, significant expansion of root dentin discoloration was observed. Moreover, the mesial roots were significantly more discolored than the distal roots. Of the 115 molars, 92 had 2 roots. Among the mesial roots of the 2-rooted teeth, 95.7% of the roots had 2 canals and 79.4% had partial/complete isthmuses and/or accessory canals. Conclusions: Dentin discoloration that was not visible on periapical radiographs and cone-beam computed tomography was frequently found in mandibular first molars that failed endodontic treatment. The complex anatomy of the mesial roots of the mandibular first molars is another reason for the failure of conventional endodontic treatment.
Yoon Jiyoung,Kim Eun-Kyung,Kim Min Jung,Moon Hee Jung,Yoon Jung Hyun,박영진 대한영상의학회 2020 Korean Journal of Radiology Vol.21 No.8
Objective: To investigate preoperative magnetic resonance imaging (MRI) findings associated with resection margin status in patients with invasive lobular carcinoma (ILC) who underwent breast-conserving surgery. Materials and Methods: One hundred and one patients with ILC who underwent preoperative MRI were included. MRI (tumor size, multifocality, type of enhancing lesion, distribution of non-mass enhancement [NME], and degree of background parenchymal enhancement) and clinicopathological features (age, pathologic tumor size, presence of ductal carcinoma in situ [DCIS] or lobular carcinoma in situ, presence of lymph node metastases, and estrogen receptor/progesterone receptor/human epidermal growth factor receptor type 2 status) were analyzed. A positive resection margin was defined as the presence of invasive cancer or DCIS at the inked surface. Logistic regression analysis was performed to determine pre- and postoperative variables associated with positive resection margins. Results: Among the 101 patients, 21 (20.8%) showed positive resection margins. In the univariable analysis, NME, multifocality, axillary lymph node metastasis, and pathologic tumor size were associated with positive resection margins. With respect to preoperative MRI findings, multifocality (odds ratio [OR] = 3.977, p = 0.009) and NME (OR = 2.741, p = 0.063) were associated with positive resection margins in the multivariable analysis, although NME showed borderline significance. Conclusion: In patients with ILC, multifocality and the presence of NME on preoperative breast MRI were associated with positive resection margins.
Yoon, Joo-Eun,Yoo, Kyu-Cheul,Macdonald, Alison M.,Yoon, Ho-Il,Park, Ki-Tae,Yang, Eun Jin,Kim, Hyun-Cheol,Lee, Jae Il,Lee, Min Kyung,Jung, Jinyoung,Park, Jisoo,Lee, Jiyoung,Kim, Soyeon,Kim, Seong-Su,Ki Copernicus GmbH 2018 Biogeosciences Vol.15 No.19
<P><p><strong>Abstract.</strong> Since the start of the industrial revolution, human activities have caused a rapid increase in atmospheric carbon dioxide (<span class='inline-formula'>CO<sub>2</sub></span>) concentrations, which have, in turn, had an impact on climate leading to global warming and ocean acidification. Various approaches have been proposed to reduce atmospheric <span class='inline-formula'>CO<sub>2</sub></span>. The Martin (or iron) hypothesis suggests that ocean iron fertilization (OIF) could be an effective method for stimulating oceanic carbon sequestration through the biological pump in iron-limited, high-nutrient, low-chlorophyll (HNLC) regions. To test the Martin hypothesis, 13 artificial OIF (aOIF) experiments have been performed since 1990 in HNLC regions. These aOIF field experiments have demonstrated that primary production (PP) can be significantly enhanced by the artificial addition of iron. However, except in the Southern Ocean (SO) European Iron Fertilization Experiment (EIFEX), no significant change in the effectiveness of aOIF (i.e., the amount of iron-induced carbon export flux below the winter mixed layer depth, MLD) has been detected. These results, including possible side effects, have been debated amongst those who support and oppose aOIF experimentation, and many questions concerning the effectiveness of scientific aOIF, environmental side effects, and international aOIF law frameworks remain. In the context of increasing global and political concerns associated with climate change, it is valuable to examine the validity and usefulness of the aOIF experiments. Furthermore, it is logical to carry out such experiments because they allow one to study how plankton-based ecosystems work by providing insight into mechanisms operating in real time and under in situ conditions. To maximize the effectiveness of aOIF experiments under international aOIF regulations in the future, we therefore suggest a design that incorporates several components. (1) Experiments conducted in the center of an eddy structure when grazing pressure is low and silicate levels are high (e.g., in the SO south of the polar front during early summer). (2) Shipboard observations extending over a minimum of <span class='inline-formula'>∼40</span> days, with multiple iron injections (at least two or three iron infusions of <span class='inline-formula'>∼2000</span><span class='thinspace'></span><span class='inline-formula'>kg</span> with an interval of <span class='inline-formula'>∼10</span>-15 days to fertilize a patch of 300<span class='thinspace'></span><span class='inline-formula'>km<sup>2</sup></span> and obtain a <span class='inline-formula'>∼2</span><span class='thinspace'></span><span class='inline-formula'>nM</span> concentration). (3) Tracing of the iron-fertilized patch using both physical (e.g., a drifting buoy) and biogeochemical (e.g., sulfur hexafluoride, photosynthetic quantum efficiency, and partial pressure of <span class='inline-formula'>CO<sub>2</sub></span>) tracers. (4) Employment of neutrally buoyant sediment traps (NBST) and application of the water-column-derived thorium-234 (<span class='inline-formula'><sup>234</sup>Th</span>) method at two depths (i.e., just below the in situ MLD and at the winter MLD), with autonomous profilers equipped with an underwater video profiler (UVP) and a transmissometer. (5) Monitoring of side effects on marine/ocean ecosystems, including production of climate-relevant gases (e.g., nitrous oxide, <span class='inline-formula'>N<sub>2</sub>O</span>; dimethyl sulfide, DMS; and halogenated volatile organic compounds, HVOCs), decline in oxygen inventory, and development of toxic algae blooms, with optical-sensor-equipped autonomous moored profilers and/or autonomous benthic vehicles. Lastly, we introduce the scientific aOIF<span id='page5848'/> experimental design guidelines for a future Korean Iron Fertilization Experiment in the Southern Ocean (KIFES).</p> </P>
Atypical Manifestation of Primary Hepatocellular Carcinoma and Hepatic Malignancy Mimicking Lesions
Jiyoung Yoon,So Hyun Park,Su Joa Ahn,Young Sup Shim 대한영상의학회 2022 대한영상의학회지 Vol.83 No.4
Hepatocellular carcinoma (HCC) can be diagnosed noninvasively on multiphasic CT and MRI based on its distinctive imaging findings. These features include arterial phase hyperenhancement and washout on portal or delayed phase images. However, radiologists face significant diagnostic challenges because some HCCs exhibit atypical imaging characteristics. In addition to many HCC-mimicking lesions, such as arterioportal shunts, combined HCC-cholangiocarcinoma, intrahepatic cholangiocarcinoma, and hemangioma present a challenge for radiologists in actual clinical practice. The ability to distinguish HCCs from mimickers on initial imaging examinations is crucial for appropriate management and treatment decisions. Therefore, this pictorial review presents the imaging findings of atypical HCCs and HCCs mimicking malignant and benign lesions and discusses important clues that may help narrow down the differential diagnosis.