• Restorative Dentistry and Endodontics
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• v.30 no.5
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• pp.355-362
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• 2005

The purpose of this study was to compare the effect on marginal leakage of a resin surface sealant (Biscover) applied before or after polymerization of composite resin to unsealed composite restorations. Thirty Class V cavities with the occlusal margin in enamel and cervical margin in dentin or cementum were prepared on the buccal surfaces of sound extracted molars and restored with a microfilled light-cured composite resin (Micronew). Restorations were randomly assigned into one of three equal groups (n = 10): a control group - no surface sealing, group 1 - applied Biscover after polymerization of the composite resin. and group 2 - applied Biscover before polymerization of the composite resin. Specimens were thermocycled, immersed in a $20\%$ methylene blue solution for 4 hoots, sectioned longitudinally, and analyzed for leakage at the occlusal and gingival margins. The results of this study were as follows 1. In sealed group, group 2 showed higher microleakage than group 1 at both occlusal and gingival margins. but there was no significant difference between two groups (p > 0.05). 2. Unsealed control group showed a little higher microleakage than sealed group at occlusal margins, and a little Higher or similar microleakage than sealed group at gingival margins (p > 0.05) 3. Control group and group 2 showed significantly less microleakage at the occlusal margins, but group 1 showed no significantly difference between microleakage at the occlusal and gingival margins.

• Restorative Dentistry and Endodontics
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• v.29 no.2
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• pp.162-169
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• 2004

This study evaluated the marginal microleakage of five single step adhesives. Class V cavity preparations with occlusal margins in enamel and gingival margins in dentin were prepared on both buccal and lingual surfaces of extracted human molar teeth. Prepared teeth were randomly divided into five groups and restored using one of the single step adhesives and composite resins：Prompt L-Pop/Filtek Z-250 (Group 1), AQ Bond/Metafil CX (Group 2), One-Up Bond F/Palfique Toughwell (Group 3). Futurabond/Admira (Group 4), Xeno III/Spectrum TPH (Group 5). The restored teeth were thermocycled. Microleakage was assessed by dye penetration using 2% methylene blue dye solution. The teeth were bisected buccolingually and evaluated for microleakage under steromicroscope. The data were statistically analysed by Kruskal-Wallis test and Mann-Whitney tests. The results of this study were as follows：1. Microleakage of enamel margins in group 3 was statistically higher than that in groups 1, 2, 4, 5 (p < 0.05). 2. Microleakage of dentin margins in group 1 was statistically higher than that in groups 2, 5, and that in group 3 was statistically higher than that in groups 2, 4, 5 (p < 0.05). 3. Dentin marginal microleakage was higher than enamel marginal microleakage in all experimental groups. In conclusion, Prompt L-Pop showed the least leakage at enamel margin, and AQ Bond showed at dentin margin in this study. Marginal miroleakage in dentin was higher than that in enamel.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.491-497
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• 1993

In MIMO design, input and output units are different from each other. By this reason, the effect of larger units to smaller one is not trivial and there is no method of proper scaling, optimal scaling. In this paper, robust stability of MIMO LQG/LTR design are analised when the plnat inputs and outputs are scalled. The upper bound of model error to guarantee the robust stability is obtained, and gain margin and phase margins are computed with respect to scalling matrices.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.12
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• pp.1014-1021
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• 1989

The problem of controlling static gaits for a quadruped walking robot is investigated. A theoretical approach to gait study is proposed in which the static stability margins for periodic gaits are expressed in terms of the kinematic gait formula. The effects fo the stride length on static stability are analyzed and the relations between static stability and initial body configurations are examined. It is shown that the moving velocity can be increased to some extent without affecting stability margins for a given initial body configuration. Computer simulations are performed to verify the analysis.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.356-361
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• 1986

This paper presents robustness properties of LQ regulators for input-delayed systems. Using frequency-domain representations, the Kalman inequality concerning the return-difference matrix is derived. The stability margins of LQ regulators are investigated using the Kalman inequality when the open-loop system is stable. In order to obtain stability margins a upper bound of the solution of LQ Riccati equations is derived. Finally, the LQG/LTR method to improve the robustness of LQG regulators is obtained and illustrated with an example.

• Journal of Gastric Cancer
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• v.11 no.3
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• pp.155-161
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• 2011

Purpose: To determine the diagnostic utility of a frozen section biopsy in patients undergoing endoscopic submucosal dissection (ESD) for early gastric neoplasms with obscure margins even with chromoendoscopy using acetic acid and indigo carmine (AI chromoendoscopy). Materials and Methods: The lateral spread of early gastric neoplasms was unclear even following AI chromoendoscopy in 38 patients who underwent ESD between June 2007 and May 2011. Frozen section biopsies were obtained by agreement of the degree of lateral spread between two endoscopists. Thus, frozen section biopsies were obtained from 23 patients (FBx group) and not in the other 15 patients (AI group). Results: No significant differences were observed for size, histology, invasive depth, and location of lesions between the AI and FBx groups. No false positive or false negative results were observed in the frozen section diagnoses. Adenocarcinoma was revealed in three patients and tubular adenoma in one, thereby changing the delineation of lesion extent and achieving free lateral margins. The rates of free lateral resection margins and curative resection were significantly higher in the FBx group than those in the AI group. Conclusions: Frozen section biopsy can help endoscopists perform more safe and accurate ESD in patients with early gastric neoplasm.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4717-4721
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• 2013

Complete surgical resection of the primary tumour is a crucial predictive step for head and neck squamous cell carcinoma (HNSCC), because incomplete resection may lead to increase in the recurrence rate. Molecular cancer markers have been investigated as potential predictors of prognosis marker, to identify patients who are at high risk of local recurrence. This retrospective study aimed to determine the prognostic correlation between p53 and eIF4E expression and clinical characteristics, recurrence and overall survival. Forty eight HNSCC patients were selected between 2006 and 2009 diagnosed at the Royal Darwin Hospital, Darwin, Northern Territory, Australia. Out of 48, only those 24 with negative surgical margins with hematoxylin and eosin (HandE) were chosedn for further analysis. A total of 77 surgical margins were obtained and subsequently analysed by immunohistochemical (IHC) staining with monoclonal p53 and polyclonal eIF4E antibodies. Contingency table and ${\chi}^2$-test were used to investigate the correlation between p53 and eIF4E expression and clinical characteristics, recurrence and overall survival of the HNSCC patients. The follow up period was 74 months (range 1-74 months). The Kaplan-Meier method was used to generate recurrence and survival curves. This is a first retrospective study of Northern Territory patients, including Indigenous and non-Indigenous Australians. Molecular study of surgical margins could help to identify patients with and without clear margins after surgery and help in choice of the most appropriate adjuvant treatment for HNSCC patients.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.205-213
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• 1993

The purpose of the study was to evaluate the degree of the marginal leakage of esthetic restorative materials on root caries restoration. 120 cavities were prepared to $90^{\circ}$ butt joint on all margins on the crown and root portion, and divided into 4 groups. The four groups of cavity were filled with Amalgam(Dongmuyung Dental Alloy Co., Ltd, KOREA), Silux$^{(R)}$(3M Co., USA)-Scotch Bond 2$^{(R)}$(3M Co., USA), Silux$^{(R)}$-All Bond$^{(R)}$(BISCO USA), and GC Fuji II$^{(R)}$(G-C Co., JAPAN) respectively. The apical margin of the preparation was finished to leave a flash of restorative material. The coronal margin of the preparation was finished not to leave a flash of restorative material. All specimens were sectioned longitudinally with Isomet Low speed saw(Buether Ltd, USA). The degree of dye penetration was evaluated as the parameter of marginal leakage under the stereoscope. The results were as follows. 1. At the enamel and dentin/cementum margins, the margin were finished to leave a flash of material showed less marginal leakage than that were finished not to leave a flash of material (P<0.001). 2. The enamel margins showed less marginal leakage than the dentin/cementum margins(P<0.001). 3. There was no significant difference in the degree of the marginal leakage between Silux$^{(R)}$-Scotch Bond 2$^{(R)}$ group and Silux$^{(R)}$-All Bond$^{(R)}$ group.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1053-1065
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• 2018

Objective: To evaluate the clinical impact of using registration software for ablative margin assessment on pre-radiofrequency ablation (RFA) magnetic resonance imaging (MRI) and post-RFA computed tomography (CT) compared with the conventional side-by-side MR-CT visual comparison. Materials and Methods: In this Institutional Review Board-approved prospective study, 68 patients with 88 hepatocellulcar carcinomas (HCCs) who had undergone pre-RFA MRI were enrolled. Informed consent was obtained from all patients. Pre-RFA MRI and post-RFA CT images were analyzed to evaluate the presence of a sufficient safety margin (${\geq}3mm$) in two separate sessions using either side-by-side visual comparison or non-rigid registration software. Patients with an insufficient ablative margin on either one or both methods underwent additional treatment depending on the technical feasibility and patient's condition. Then, ablative margins were re-assessed using both methods. Local tumor progression (LTP) rates were compared between the sufficient and insufficient margin groups in each method. Results: The two methods showed 14.8% (13/88) discordance in estimating sufficient ablative margins. On registration software-assisted inspection, patients with insufficient ablative margins showed a significantly higher 5-year LTP rate than those with sufficient ablative margins (66.7% vs. 27.0%, p = 0.004). However, classification by visual inspection alone did not reveal a significant difference in 5-year LTP between the two groups (28.6% vs. 30.5%, p = 0.79). Conclusion: Registration software provided better ablative margin assessment than did visual inspection in patients with HCCs who had undergone pre-RFA MRI and post-RFA CT for prediction of LTP after RFA and may provide more precise risk stratification of those who are treated with RFA.

• Investigative Magnetic Resonance Imaging
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• v.25 no.1
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• pp.23-34
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• 2021

Purpose: Differentiating between glioblastoma and solitary metastasis is very important for the planning of further workup and treatment. We assessed the ability of various morphological parameters using conventional MRI and diffusion-based techniques to distinguish between glioblastomas and solitary metastases in tumoral and peritumoral regions. Materials and Methods: We included 38 patients with solitary brain tumors (21 glioblastomas, 17 solitary metastases). To find out if there were differences in the morphologic parameters of enhancing tumors, we analyzed their shape, margins, and enhancement patterns on postcontrast T1-weighted images. During analyses of peritumoral regions, we assessed the extent of peritumoral non-enhancing lesion on T2- and postcontrast T1-weighted images. We also aimed to detect peritumoral neoplastic cell infiltration by visual assessment of T2-weighted and diffusion-based images, including DWI, ADC maps, and exponential DWI, and evaluated which sequence depicted peritumoral neoplastic cell infiltration most clearly. Results: The shapes, margins, and enhancement patterns of tumors all significantly differentiated glioblastomas from metastases. Glioblastomas had an irregular shape, ill-defined margins, and a heterogeneous enhancement pattern; on the other hand, metastases had an ovoid or round shape, well-defined margins, and homogeneous enhancement. Metastases had significantly more extensive peritumoral T2 high signal intensity than glioblastomas had. In visual assessment of peritumoral neoplastic cell infiltration using T2-weighted and diffusion-based images, all sequences differed significantly between the two groups. Exponential DWI had the highest sensitivity for the diagnosis of both glioblastoma (100%) and metastasis (70.6%). A combination of exponential DWI and ADC maps was optimal for the depiction of peritumoral neoplastic cell infiltration in glioblastoma. Conclusion: In the differentiation of glioblastoma from solitary metastatic lesions, visual morphologic assessment of tumoral and peritumoral regions using conventional MRI and diffusion-based techniques can also offer diagnostic information.