• Korean Journal of Radiology
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• v.2 no.4
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• pp.197-203
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• 2001

Objective: To compare the clinical utility of contrast-enhanced color Doppler US in the differentiation of retinal detachment (RD) from vitreous membrane (VM) with that of various conventional US modalities, and to analyze the enhancement patterns in cases showing an enhancement effect. Materials and Methods: In 32 eyes examined over a recent two-year period, RD (n=14) and VM (n=18) were confirmed by surgery (n=28) or clinical follow-up (n=4). In all cases, gray-scale, color Doppler, and power Doppler US were performed prior to contrast injection, and after the intravenous injection of Levovist (Schering, Berlin) by hand for 30 seconds at a dose of 2.5 g and a concentration of 300 mg/mL via an antecubital vein, contrast-enhanced color Doppler US was performed. At Doppler US, the diagnostic criterion for RD and VM was whether or not color signals were visualized in membranous structures. Results: Diagnostic accuracy was 78% at gray-scale US, 81% at color Doppler US, 59% at power Doppler US, and 97% at contrast-enhanced color Doppler US. The sensitivity of color Doppler US to color signals in RD increased from 57% to 93% after contrast enhancement. The enhancement patterns observed were signal accentuation (n=3), signal extension (n=2), signal addition (n=3), and new signal visualization (n=5). Conclusion: Contrast-enhanced color Doppler US was the most accurate US modality for differentiating RD from VM, showing a significantly increased signal detection rate in RD.

• Journal of Korean Physical Therapy Science
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• v.11 no.3
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• pp.5-13
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• 2004

The use of therapeutic ultrasound(US) in humans with malignant neoplasms has been contra-indicated in physical therapy practice. Some studies have shown the results after application of US inhibited of tumor growth but some studies have shown the results facilitated of tumor growth in mouse. The purpose of this study were to determine the effects of US on rectal sarcoma(CT-26) in mouse and to determine the histological change of tumor. Thirty-five female BALB/C mouse, age 6 to 8 weeks received subcutaneous injection of 0.1 105 tumor cells. When tumors grew to 5 mm in diameters, the mouse were randomly assigned to control group(n=7) and high powered continuous US group(n=7) and low powered continuous US group(n=7) and high powered pulsed US group(n=7) and low powered pulsed US group(n=7). The experimental group (four groups) received 10 treatments over a 10-day period of 3 MHz ultrasound. Tumor dimension were measured on days 1(start of treatment), 5(midtreatment), and 10(end of treatment, preexcision and postexcision). Tumors were weighed after excision and the mouse were observated histological change of tumor. All tumors grew larger over time. Mean tumor weights(in grams) and volumes(in cubic millimeters) were 2.063 g and $2729.313\;mm^3$ for the high powered continuous US group 1.881 g and $2428.002\;mm^3$ for the low powered continuous US group 1.730 g and $2381.002\;mm^3$ for the high powered pulsed US 1.673 g and $2289.562\;mm^3$ for the low powered pulsed US group 1.670 g and $2297.333\;mm^3$ for the control group. Ultrasound increased the weight and volume of subcutaneous tumor in mouse. We urge caution in the use of ultrasound in the areas of tumors.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3179-3183
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• 2014

Background: The purpose of study was to evaluate radiologic or clinical features of breast cancer undergoing ultrasound (US)-guided 14G core needle biopsy (CNB) and analyze the differences between underestimated and accurately diagnosed groups. Materials and Methods: Of 1,898 cases of US-guided 14G CNB in our institute, 233 cases were proven to be cancer by surgical pathology. The pathologic results from CNB were invasive ductal carcinoma (IDC) (n=157), ductal carcinoma in situ (DCIS) (n=40), high-risk lesions in 22 cases, and benign in 14 cases. Among high-risk lesions, 7 cases of atypical ductal hyperplasia (ADH) were reported as cancer and 11 cases of DCIS were proven IDC in surgical pathology. Some 29 DCIS cases and 157 cases of IDC were correctly diagnosed with CNB. The clinical and imaging features between underestimated and accurately diagnosed breast cancers were compared. Results: Of 233 cancer cases, underestimation occurred in 18 lesions (7.7%). Among underestimated cancers, CNB proven ADH (n=2) and DCIS (n=11) were diagnosed as IDC and CNB proven ADH (n=5) were diagnosed at DCIS finally. Among the 186 accurately diagnosed group, the CNB results were IDC (n=157) and DCIS (n=29). Comparison of underestimated and accurately diagnosed groups for BI-RADS category, margin of mass on mammography and US and orientation of lesion on US revealed statistically significant differences. Conclusions: Underestimation of US-guided 14G CNB occurred in 7.7% of breast cancers. Between underestimated and correctly diagnosed groups, BI-RADS category, margin of the mass on mammography and margin and orientation of the lesions on US were different.

• Korean Journal of Radiology
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• v.21 no.5
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• pp.598-604
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• 2020

Objective: Proper management of lymph nodes (LNs) with ultrasonographic (US) indeterminate features in thyroid cancer patients remains elusive. We aimed to evaluate the malignancy risk and US findings predictive of malignancy for US indeterminate LNs in preoperative thyroid cancer patients through node-by-node correlation. Materials and Methods: A total of 348 LNs in 284 thyroid cancer patients, who underwent fine-needle aspiration or core-needle biopsy between December 2006 and June 2015, were included. We determined the malignancy risks for US probably benign, indeterminate, and suspicious categories. For US indeterminate LNs, which had neither echogenic hilum nor hilar vascularity in the absence of any suspicious finding, US findings were compared between benign and metastatic LNs using Mann-Whitney U test and Fisher's exact test. Results: US imaging diagnoses were probably benign in 20.7% (n = 72) cases, indeterminate in 23.6% (n = 82), and suspicious in 55.7% (n = 194). Malignancy risk of US indeterminate LNs (19.5% [16/82]) differed from those of the US probably benign (2.8% [2/72]) (p = 0.002) and US suspicious LNs (78.4% [152/194]) (p < 0.001). Among US indeterminate LNs, there were no significant differences in short, long, and long-to-short diameter (L/S) ratios between benign and metastatic LNs (3.9 vs. 3.8 mm, p = 0.619; 7.3 vs. 7.3 mm, p = 0.590; 1.9 vs. 1.9, p = 0.652). Conclusion: US indeterminate LNs were frequently encountered during preoperative evaluation and had intermediate malignancy risk. Given the lack of discriminative power of size criteria and L/S ratio, clinical factors such as surgical strategy and node size should be considered for proper triage of US indeterminate LNs in thyroid cancer.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.189.1-189.1
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• 2003

4-(4-Methoxyphenyl)-2-aminothiazole and 3-(4-methoxyphenyl)-5-aminothiadiazole derivatives have been synthesized and evaluated as selective antagonists for human adenosine A$_3$ receptors. A methoxy group in the 4-position of the phenyl ring and N-acetyl or propionyl substitutions of the aminothiazole and aminothiadiazole templates displayed great increases of binding affinity and selectivity for human adenosine A$_3$ receptors. The most potent A$_3$ antagonist of the present series, N-［3-(4-methoxy-phenyl)-［1,2,4］thiadiazol-5-yl］-acetamide exhibiting a K$\_$i/ value of 0.79 nM at human adenosine A$_3$ receptors, showed antagonistic property in functional assay of cAMP biosynthesis involved in one of the signal transduction pathways of adenosine A$_3$ receptors. (omitted)

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.1
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• pp.56-62
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• 2007

In this paper, design method for power tower hazard diagnosis/predition system based on UsN was proposed. The proposed method used multi-hybrid sensors to measure rotation, displacement, and inclination state of power tower, and made decision/prediction of hazard of power tower. System design was made with requirement analysis of monitoring for transmission power facility and use of MEMS and optic fiber sensors. For hazard decision, analysis of correlation was made using sensor output. LN based on IEC61850,international standard for digital substation, was also proposed. For transmission facility monitoring, digital substation and power tower were considered as parts of power facility networks.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.30-36
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• 2020

We demonstrated a successful fabrication of 4" Gallium Nitride (GaN)/Diamond High Electron Mobility Transistors (HEMTs) incorporated with Inner Slot Via Hole process. We made in manufacturing technology of 4" GaN/Diamond HEMT wafers in a compound semiconductor foundry since reported [1]. Wafer thickness uniformity and wafer flatness of starting GaN/Diamond wafers have improved greatly, which contributed to improved processing yield. By optimizing Laser drilling techniques, we successfully demonstrated a through-substrate-via process, which is last hurdle in GaN/Diamond manufacturing technology. To fully exploit Diamond's superior thermal property for GaN HEMT devices, we include Aluminum Nitride (AlN) barrier in epitaxial layer structure, in addition to conventional Aluminum Gallium Nitride (AlGaN) barrier layer. The current collapse revealed very stable up to Vds = 90 V. The trapping behaviors were measured Emission Microscope (EMMI). The traps are located in interface between Silicon Nitride (SiN) passivation layer and GaN cap layer.

• Journal of the Korean Mathematical Society
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• v.56 no.6
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• pp.1599-1611
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• 2019

Let $m,n{\in}{\mathbb{N}}$. We represent the additive subgroups of the ring ${\mathbb{Z}}_m{\times}{\mathbb{Z}}_n$, which are also (unital) subrings, and deduce explicit formulas for $N^{(s)}(m,n)$ and $N^{(us)}(m,n)$, denoting the number of subrings of the ring ${\mathbb{Z}}_m{\times}{\mathbb{Z}}_n$ and its unital subrings, respectively. We show that the functions $(m,n){\mapsto}N^{u,s}(m,n)$ and $(m,n){\mapsto}N^{(us)}(m,n)$ are multiplicative, viewed as functions of two variables, and their Dirichlet series can be expressed in terms of the Riemann zeta function. We also establish an asymptotic formula for the sum $\sum_{m,n{\leq}x}N^{(s)}(m,n)$, the error term of which is closely related to the Dirichlet divisor problem.

• Physical Therapy Korea
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• v.4 no.1
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• pp.11-19
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• 1997

The use of therapeutic ultrasound(US) in humans with malignant neoplasms has been contraindicated in physical therapy practice. Some studies have shown that results after application of US differ according to tumor type and penetration depth. The purposes of this study were to determine the effects of US on melanoma in mice and to determine treatment dosage. Twenty-four female C57BL/6 mice, age 8 weeks. The right flank of all mice was shaved, and a 0.1 ml suspension of cells was injected subcutaneously into the animals' right flank. In this study, 24 subjects were randomly divided into three groups: experimental group 1(n=8), experimental group 2(n=8), control group(n=8). In the experimental group 1, animals received continuous 3 MHZ US treatment, administered at $2.0W/cm^2$ for five minutes. In experimental group 2, animals received continuous 3 MHz US treatment, administered at $1.0W/cm^2$ for 5 minutes. The control group received the same handling as other experimental groups, including rodent chow, water, US gel application but US head pressure without the power turned on. After 10 days treatment, all mice were killed with a potassium solution. Tumors were excised and weighed on an electrical balance and fixed in a 10% neutral buffered formalin solution. Tumor weights were smaller in experimental group 2(0.3838 g) than in the control group(0.6275 g). Tumor weights of the experimental group 1(0.015 g) were smaller than those of experimental group 2. Continuous therapeutic US decreased the weight of subcutaneous melanoma tumors in mice. The treatment dosage($2.0W/cm^2$) we suggest was more effective than earlier studies on decreasing tumor size with ultrasound.

• Korean Journal of Radiology
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• v.1 no.4
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• pp.185-190
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• 2000

Objective: To document the imaging findings of hepatic cavernous hemangioma detected in cirrhotic liver. Materials and Methods: The imaging findings of 14 hepatic cavernous hemangiomas in ten patients with liver cirrhosis were retrospectively analyzed. A diagnosis of hepatic cavernous hemangioma was based on the findings of two or more of the following imaging studies: MR, including contrast-enhanced dynamic imaging (n = 10), dynamic CT (n = 4), hepatic arteriography (n = 9), and US (n = 10). Results: The mean size of the 14 hepatic hemangiomas was 0.9 (range, 0.5-1.5) cm in the longest dimension. In 11 of these (79%), contrast-enhanced dynamic CT and MR imaging showed rapid contrast enhancement of the entire lesion during the early phase, and hepatic arteriography revealed globular enhancement and rapid filling-in. On contrast-enhanced MR images, three lesions (21%) showed partial enhancement until the 5-min delayed phases. US indicated that while three slowly enhancing lesions were homogeneously hyperechoic, 9 (82%) of 11 showing rapid enhancement were not delineated. Conclusion: The majority of hepatic cavernous hemangiomas detected in cirrhotic liver are small in size, and in many, hepatic arteriography and/or contrast-enhanced dynamic CT and MR imaging demonstrates rapid enhancement. US, however, fails to distinguish a lesion of this kind from its cirrhotic background.