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RISS 인기검색어
- 검색키워드
- 저자 : Miran Lee (검색결과 199 건)
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Lee, Donghyeon,Lee, Jiseoc,Kim, Hyoyi,Lee, Taewon,Soh, Jeongtae,Park, Miran,Kim, Changhwan,Lee, Yeon Ju,Cho, Seungryong IEEE 2017 IEEE transactions on medical imaging Vol.36 No.12
<P>A single-scan dual-energy low-dose cone-beam CT (CBCT) imaging technique that exploits a multi-slit filter is proposed in this paper. The multi-slit filter installed between the x-ray source and the scanned object is reciprocated during a scan. The x-ray beams through the slits would generate relatively low-energy x-ray projection data, while the filtered beams would make high-energy projection data. An iterative image reconstruction algorithm that uses an adaptive-steepest-descent method to minimize image total-variation under the constraint of data fidelity was applied to reconstructing the image from the low-energy projection data. Since the high-energy projection data suffer from a substantially high noise level due to the beam filtration, we have developed a new algorithm that exploits the joint sparsity between the low-and high-energy CT images for image reconstruction of the high-energy CT image. The proposed image reconstruction algorithm uses a gradient magnitude image (GMI) of the low-energy CT image by regularizing the difference of GMIs of the low-and high-energy CT images to be minimized. The feasibility of the proposed technique has been demonstrated by the use of various phantoms in the experimental CBCT setup. Furthermore, based on the proposed dual-energy imaging, a material differentiation was performed and its potential utility has been shown. The proposed imaging technique produced promising results for its potential application to a low-dose single-scan dual-energy CBCT.</P>
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Torque Control for Sensor Equipped Motor-harmonic Drive System
Miran Lee,Bumjoo Lee 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.1
In this paper, the torque control algorithm for Sensor Equipped Motor-Harmonic Drive System is proposed. For the model-based control, the dynamic equation of the harmonic drive and the electric motor was derived as a lumped model, and the frictions of the harmonic drive and the bearings were regarded as disturbance. Consequently, a linear model in which the disturbance acts on the second order system without damping was formulated. The disturbance was estimated from the disturbance observer (DOB) and forward-compensated. Subsequently, the second order system without damping was stabilized by the three different kind of feedback algorithms. First, the integral differentiator control (ID control) algorithm was developed by using pole-zero cancellation. When the model parameters are incorrect, however, the system becomes unstable. To resolve this, the PID controller was considered to make the closed loop system as a second order standard form with damping. The PID controller is stable but has some chattering in steady state. Lastly, PD control with feed-forward augmentation was examined. Among the three controllers, the Feed-forward Augmented PD controller (FAPD controller) gived best result even with parameter inaccuracy. Control performances were verified by computer simulations and experiments with the developed.
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Lee, Wooram,Yoon, Sangwon,Choe, Jong Kwon,Lee, Miran,Choi, Yongju Elsevier 2018 Science of the Total Environment Vol.639 No.-
<P><B>Abstract</B></P> <P>This study investigates the effect of anionic surfactant modification on activated carbon (AC) to enhance the adsorption of ammonium ion in aqueous solution. Sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS) or sodium octanoate (SO) was used for the modification. At the initial aqueous concentration of 55 mg NH<SUB>4</SUB>-N/L and the adsorbent dose of 50 g/L, the SDS-modified AC showed the highest ammonium removal efficiency of 82% among the modified ACs studied. The hydrophobic group of SDS was strongly attached to AC showing almost negligible desorption after the modification. At the same time, the sulfate functional group of SDS provided ion exchange sites favorable for the ammonium ion adsorption. By maximizing SDS loading to the AC, ammonium removal efficiency can further be improved (5% increase). When Na<SUP>+</SUP>, K<SUP>+</SUP> or Ca<SUP>2+</SUP> coexisted in the ammonium solution at the concentration of 55 mg/L, the inhibition effect of these cations on ammonium removal efficiency was negligible (<5%). This study shows the potential of anionic surfactant-modified ACs as the excellent adsorbents for ammonium removal from water.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Surfactant modification improves NH<SUB>4</SUB> <SUP>+</SUP> adsorption capacity of activated carbon (AC). </LI> <LI> Surfactants used for modification are stably bound to AC. </LI> <LI> SDS and SDBS provide AC with ion exchange sites favorable for NH<SUB>4</SUB> <SUP>+</SUP> adsorption. </LI> <LI> Inhibition effect of competing ions at the same concentration as NH<SUB>4</SUB> <SUP>+</SUP> is negligible. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Lee Miran,Hwang Jae-Yeon,Park Su Eun,Jung Sungsu,Jo Kyo Jin 대한의학회 2022 Journal of Korean medical science Vol.37 No.31
Coronavirus disease 2019 (COVID-19) is usually less severe in children and adolescents than in adults. However, it can cause severe respiratory illness in a small proportion of children with risk factors. Here, we report a rare case of a 10-year-old boy with postinfectious bronchiolitis obliterans that developed after pneumonia caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This patient was previously healthy apart from a high body mass index (BMI, 30.13; 99.6th percentile for the age bracket), history of preterm birth (35 weeks), and low birth weight (1,850 g). He had persistent exertional dyspnea after recovering from SARS-CoV-2-related pneumonia. Spirometry revealed obstructive lung disease with the following results: predicted forced vital capacity (FVC%pred), 71%; forced expiratory volume in 1 second (FEV1%pred), 63%; FEV1/FVC, 0.81; and forced expiratory flow25-75%pred, 55%. Chest computed tomography showed multifocal areas of parenchymal hyperlucency and mosaic attenuation in both lungs. This case suggests that careful observation of children with obesity and low birth weight is necessary after recovery from SARS-CoV-2-related pneumonia.
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Lee Jeong Hoon,Ha Eun Ju,Lee Da Hyun,Han Miran,Park Jung Hyun,Kim Ji-hoon 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.7
Objective: Preoperative differential diagnosis of follicular-patterned lesions is challenging. This multicenter cohort study investigated the clinicoradiological characteristics relevant to the differential diagnosis of such lesions. Materials and Methods: From June to September 2015, 4787 thyroid nodules (≥ 1.0 cm) with a final diagnosis of benign follicular nodule (BN, n = 4461), follicular adenoma (FA, n = 136), follicular carcinoma (FC, n = 62), or follicular variant of papillary thyroid carcinoma (FVPTC, n = 128) collected from 26 institutions were analyzed. The clinicoradiological characteristics of the lesions were compared among the different histological types using multivariable logistic regression analyses. The relative importance of the characteristics that distinguished histological types was determined using a random forest algorithm. Results: Compared to BN (as the control group), the distinguishing features of follicular-patterned neoplasms (FA, FC, and FVPTC) were patient’s age (odds ratio [OR], 0.969 per 1-year increase), lesion diameter (OR, 1.054 per 1-mm increase), presence of solid composition (OR, 2.255), presence of hypoechogenicity (OR, 2.181), and presence of halo (OR, 1.761) (all p < 0.05). Compared to FA (as the control), FC differed with respect to lesion diameter (OR, 1.040 per 1-mm increase) and rim calcifications (OR, 17.054), while FVPTC differed with respect to patient age (OR, 0.966 per 1-year increase), lesion diameter (OR, 0.975 per 1-mm increase), macrocalcifications (OR, 3.647), and non-smooth margins (OR, 2.538) (all p < 0.05). The five important features for the differential diagnosis of follicular-patterned neoplasms (FA, FC, and FVPTC) from BN are maximal lesion diameter, composition, echogenicity, orientation, and patient’s age. The most important features distinguishing FC and FVPTC from FA are rim calcifications and macrocalcifications, respectively. Conclusion: Although follicular-patterned lesions have overlapping clinical and radiological features, the distinguishing features identified in our large clinical cohort may provide valuable information for preoperative distinction between them and decision-making regarding their management.
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Lee, Eun Young,Seo, MiRan,Juhnn, Yong-Sung,Kim, Jeong Yeon,Hong, Yoo Jin,Lee, Yun Jong,Lee, Eun Bong,Song, Yeong Wook BioMed Central 2011 Arthritis research & therapy Vol.13 No.3
<P><B>Introduction</B></P><P>IFN-gamma inducible protein-10 (CXCL10), a member of the CXC chemokine family, and its receptor CXCR3 contribute to the recruitment of T cells from the blood stream into the inflamed joints and have a crucial role in perpetuating inflammation in rheumatoid arthritis (RA) synovial joints. Recently we showed the role of CXCL10 on receptor activator of nuclear factor kappa-B ligand (RANKL) expression in an animal model of RA and suggested the contribution to osteoclastogenesis. We tested the effects of CXCL10 on the expression of RANKL in RA synoviocytes and T cells, and we investigated which subunit of CXCR3 contributes to RANKL expression by CXCL10.</P><P><B>Methods</B></P><P>Synoviocytes derived from RA patients were kept in culture for 24 hours in the presence or absence of TNF-α. CXCL10 expression was measured by reverse transcriptase polymerase chain reaction (RT-PCR) of cultured synoviocytes. Expression of RANKL was measured by RT-PCR and western blot in cultured synoviocytes with or without CXCL10 and also measured in Jurkat/Hut 78 T cells and CD4+ T cells in the presence of CXCL10 or dexamethasone. CXCL10 induced RANKL expression in Jurkat T cells was tested upon the pertussis toxin (PTX), an inhibitor of Gi subunit of G protein coupled receptor (GPCR). The synthetic siRNA for Gαi<SUB>2 </SUB>was used to knock down gene expression of respective proteins.</P><P><B>Results</B></P><P>CXCL10 expression in RA synoviocytes was increased by TNF-α. CXCL10 slightly increased RANKL expression in RA synoviocytes, but markedly increased RANKL expression in Jurkat/Hut 78 T cell or CD4+ T cell. CXCL10 augmented the expression of RANKL by 62.6%, and PTX inhibited both basal level of RANKL (from 37.4 ± 16.0 to 18.9 ± 13.0%) and CXCL10-induced RANKL expression in Jurkat T cells (from 100% to 48.6 ± 27.3%). Knock down of Gα<SUB>i2 </SUB>by siRNA transfection, which suppressed the basal level of RANKL (from 61.8 ± 17.9% to 31.1 ± 15.9%) and CXCL10-induced RANKL expression (from 100% to 53.1 ± 27.1%) in Jurkat T cells, is consistent with PTX, which inhibited RANKL expression.</P><P><B>Conclusions</B></P><P>CXCL10 increased RANKL expression in CD4+ T cells and it was mediated by Gα<SUB>i </SUB>subunits of CXCR3. These results indicate that CXCL10 may have a potential role in osteoclastogenesis of RA synovial tissue and subsequent joint erosion.</P>
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Lee, Ji Hyun,Kuk, Won Kwen,Kwon, Miran,Lee, Jong Han,Lee, Kwon Sub,Yu, Il Je Informa UK, Ltd. 2013 Nanotoxicology Vol.7 No.3
<P>Safety data sheets (SDSs) and labelling are the basic hazard communication tools for hazardous chemicals as regards their manufacture, storage, transport and other handling activities. Thus, in the context of the growing use of nanomaterials and nanomaterial-containing materials, this study evaluated the information provided in 97 nanomaterial-related SDSs according to the criteria set by the GHS (Globally Harmonized System of Classification and Labelling of Chemicals) and found that most of the SDSs did not include sufficient information on the safety of nanomaterials, such as their toxicity and physicochemical properties. The reasons for this lack of information in the nanomaterial SDSs can mainly be attributed to (1) a lack of toxicity and physicochemical property information on nanomaterials, (2) unawareness of the effectiveness of conventional exposure controls, such as local exhaust ventilation and encapsulation, and personal protective equipment (PPE), in protecting against nanomaterial exposure, (3) a lack of information on emergency and firefighting measures and (4) a lack of knowledge on how existing regulations apply to nanomaterials. Therefore, to create a consistent standard for the information provided on safety, health and environmental matters for manufactured nanomaterial-containing products, guidance for the preparation of nanomaterial-specific SDSs, including both nanomaterials and mixtures of nanomaterials with conventional non-nanoscale materials, was recently initiated by the ISO TC 229. Their guidance, in the form of a technical report, recommends that nanomaterial-related SDSs should be prepared based on a precautionary approach in terms of the toxicity and other risks associated with the nanomaterial contents within the mixture in question. One of the key recommendations in the technical report is to include additional physicochemical properties, including the particle size (average and range), size distribution aggregation/agglomeration state, shape and aspect ratio, crystallinity, specific surface area, dispersibility and dustiness, which help to distinguish the characteristics of nanomaterials from those of non-nanoscale materials. The technical report also recommends the preparation of SDSs for all nanomaterials and mixtures that meet the GHS criteria for physical, health or environmental hazards, and for all mixtures containing nanomaterials that meet the criteria for carcinogenic, toxic to reproduction or specific target organ toxicity in concentrations exceeding the cut-off limits for an SDS specified by the criteria for mixtures. Finally, the technical report recommends that SDSs be prepared for all nanomaterials, unless there is evidence that they are not hazardous.</P>
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