• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.394-400
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• 2018

Purpose: This research evaluated five types of nanoparticles to develop a surface-enhanced Raman spectroscopy (SERS) method for the rapid detection of two Bacillus species (Bacillus cereus and Bacillus thuringiensis) that are commonly found on fresh produce, which can cause food poisoning. Methods: Bacterial concentrations were adjusted to a constant turbidity, and a total of $30{\mu}L$ of each Bacillus cell suspension was prepared for each nanoparticle. A point-scan Raman system with laser light source of wavelength 785 nm was used to obtain SERS data. Results: There was no qualitative difference in the SERS data of B. cereus and B. thuringiensis for any of the five nanoparticles. Three gold nanoparticles, stabilized in either citrate buffer or ethanol, showed subtle differences in Raman intensities of two Bacillus species at $877.7cm^{-1}$. Conclusions: Among the three types of nanoparticles, the gold nanoparticles stabilized in citrate buffer showed the lowest standard deviation, followed by gold nanoparticles stabilized in ethanol. This result supports the potential application of gold nanoparticles for SERS-based detection of B. cereus and B. thuringiensis.

• Journal of Yeungnam Medical Science
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• v.36 no.3
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• pp.231-240
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• 2019

Background: We sought to determine the value of combining diffusion-weighted (DW) and perfusion-weighted (PW) sequences with a conventional magnetic resonance (MR) sequence to assess solid components of borderline ovarian tumors (BOTs) and stage I carcinomas. Methods: Conventional, DW, and PW sequences in the tumor imaging studies of 70 patients (BOTs, n=38; stage I carcinomas, n=32) who underwent surgery with pathologic correlation were assessed. Two independent radiologists calculated the parameters apparent diffusion coefficient (ADC), $K^{trans}$ (vessel permeability), and $V_e$ (cell density) for the solid components. The distribution on conventional MR sequence and mean, standard deviation, and 95% confidence interval of each DW and PW parameter were calculated. The inter-observer agreement among the two radiologists was assessed. Area under the receiver operating characteristic curve (AUC) and multivariate logistic regression were performed to compare the effectiveness of DW and PW sequences for average values and to characterize the diagnostic performance of combined DW and PW sequences. Results: There were excellent agreements for DW and PW parameters between radiologists. The distributions of ADC, $K^{trans}$, and $V_e$ values were significantly different between BOTs and stage I carcinomas, yielding AUCs of 0.58 and 0.68, 0.78 and 0.82, and 0.70 and 0.72, respectively, with ADC yielding the lowest diagnostic performance. The AUCs of the DW, PW, and combined PW and DW sequences were $0.71{\pm}0.05$, $0.80{\pm}0.05$, and $0.85{\pm}0.05$, respectively. Conclusion: Combining PW and DW sequences to a conventional sequence potentially improves the diagnostic accuracy in the differentiation of BOTs and stage I carcinomas.

• Journal of Life Science
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• v.29 no.10
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• pp.1159-1163
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• 2019

Although there is a growing interest in male menopause, a phenomenon associated with male hormone depletion, current kits using antibodies to quantify male hormones are expensive. In this study, we constructed an in vitro system for verifying the activity or concentration of male steroid hormones using a transcriptional activity test. A reporter plasmid, pGL2-Neo-ARE-AdE1BTATA, which reacts to testosterone, was constructed. In this plasmid, the ARE-AdE1bTATA sequences can be bounded by the testosterone - androgen receptor complex to express luciferase as a reporter. Then, a stable transfection was performed on the human prostate cancer cell line, LNcap-LN3. The constructed LNcap-LN3/pGL2-Neo-ARE-AdE1BTATA testosterone compound detection (TCD) system showed quantitatively proportional luciferase activities to concentrations of $10^{-13}$ to $10^{-8}M$ of standard testosterone. The established in vitro TCD system will contribute to the development of materials for health/functional foods and drugs as it will be possible to search en masse for testosterone-like or testosterone-inhibiting substances derived from natural materials.

• Journal of IKEEE
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• v.23 no.1
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• pp.58-67
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• 2019

A design of an elliptic curve cryptography (ECC) processor that supports both pseudo-random curves and Koblitz curves over $GF(2^m)$ defined by the NIST standard is described in this paper. A finite field arithmetic circuit based on a word-based Montgomery multiplier was designed to support five key lengths using a datapath of fixed size, as well as to achieve a lightweight hardware implementation. In addition, Lopez-Dahab's coordinate system was adopted to remove the finite field division operation. The ECC processor was implemented in the FPGA verification platform and the hardware operation was verified by Elliptic Curve Diffie-Hellman (ECDH) key exchange protocol operation. The ECC processor that was synthesized with a 180-nm CMOS cell library occupied 10,674 gate equivalents (GEs) and a dual-port RAM of 9 kbits, and the maximum clock frequency was estimated at 154 MHz. The scalar multiplication operation over the 223-bit pseudo-random elliptic curve takes 1,112,221 clock cycles and has a throughput of 32.3 kbps.

• Brain Tumor Research and Treatment
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• v.6 no.2
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• pp.54-59
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• 2018

Background Leptomeningeal metastasis (LM) is an uncommon, but devastating complication of advanced cancer and has no standard treatment. Herein, we analyzed the clinical characteristics and outcomes of patients with solid tumors who were diagnosed with LM. Methods Between January 2007 and December 2017, we retrospectively analyzed the medical records of patients with solid tumors who were diagnosed with LM. Results A total of 58 patients were enrolled in this study. The median age of patients was 51 years (range, 27-72 years), and 62.1% had a poor Eastern Cooperative Oncology Group (ECOG) performance status (PS) (>2). The common types of primary tumor were breast cancer (39.7%), gastric cancer (25.9%), and non-small cell lung cancer (20.7%). Forty-two patients (72.4%) were diagnosed with LM by MRI of the brain and/or spine and cerebrospinal fluid (CSF) analysis, 14 were diagnosed by CSF analysis alone, and 2 were diagnosed by MRI alone. Treatments for LM were performed in 53 patients (91.4%), and best supportive care was provided for 5 patients (8.6%). Intrathecal chemotherapy, radiotherapy, and systemic chemotherapy were administered in 43 (74.1%), 17 (29.3%), and 24 (41.4%) patients, respectively. The median overall survival of the entire cohort was 2.4 months (95% confidence interval, 1.0-3.7). In the analysis of prognostic factors for survival, a good ECOG PS (${\leq}2$), administration of systemic chemotherapy after LM diagnosis, and a prior history of brain radiation were associated with prolonged survival. Conclusion Although the prognosis of LM in patients with solid tumors is poor, systemic chemotherapy might improve survival in selected patients with a good PS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.736-743
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• 2020

Modular multiplication is one of the most important arithmetic operations in public-key cryptography such as elliptic curve cryptography (ECC) and RSA, and the performance of modular multiplier is a key factor influencing the performance of public-key cryptographic hardware. An efficient hardware implementation of word-based Montgomery modular multiplication algorithm is described in this paper. Our modular multiplier was designed to support eleven field sizes for prime field GF(p) and binary field GF(2k) as defined by SEC2 standard for ECC, making it suitable for lightweight hardware implementations of ECC processors. The proposed architecture employs pipeline scheme between the partial product generation and addition operation and the modular reduction operation to reduce the clock cycles required to compute modular multiplication by 50%. The hardware operation of our modular multiplier was demonstrated by FPGA verification. When synthesized with a 65-nm CMOS cell library, it was realized with 33,635 gate equivalents, and the maximum operating clock frequency was estimated at 147 MHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.268-275
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• 2020

A lightweight hardware design of self-timed ring based true random number generator (TRNG) suitable for information security applications is described. To reduce hardware complexity of TRNG, an entropy extractor with feedback structure was proposed, which minimizes the number of ring stages. The number of ring stages of the FSTR-TRNG was determined to be a multiple of eleven, taking into account operating clock frequency and entropy extraction circuit, and the ratio of tokens to bubbles was determined to operate in evenly-spaced mode. The hardware operation of FSTR-TRNG was verified by FPGA implementation. A set of statistical randomness tests defined by NIST 800-22 were performed by extracting 20 million bits of binary sequences generated by FSTR-TRNG, and all of the fifteen test items were found to meet the criteria. The FSTR-TRNG occupied 46 slices of Spartan-6 FPGA device, and it was implemented with about 2,500 gate equivalents (GEs) when synthesized in 180 nm CMOS standard cell library.

• Biomaterials Research
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• v.22 no.4
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• pp.346-351
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• 2018

Background: Carbonate apatite ($CO_3Ap$) and silica-calcium phosphate composite (SCPC) are bone substitutes with good prospect for dental application. SCPC creates a hydroxyapatite surface layer and stimulate bone cell function while, $CO_3Ap$ induce apatite crystal formation with good adaptation providing good seal between cement and the bone. Together, these materials will add favorable properties as a pulp capping material to stimulate mineral barrier and maintain pulp vitality. The aim of this study is to investigate modification of $CO_3Ap$ cement combined with SCPC, later term as $CO_3Ap-SCPC$ cement (CAS) in means of its chemical (Calcium release) and physical properties (setting time, DTS and pH value). Methods: The study consist of three groups; group 1 (100% calcium hydroxide, group 2 $CO_3Ap$ (60% DCPA: 40% vaterite, and group 3 CAS (60% DCPA: 20% vaterite: 20% SCPC. Distilled water was employed as a solution for group 1, and $0.2mol/L\;Na_3PO_4$ used for group 2 and group 3. Samples were evaluated with respect to important properties for pulp capping application such as pH, setting time, mechanical strength and calcium release evaluation. Results: The fastest setting time was in $CO_3Ap$ cement group without SCPC, while the addition of 20% SCPC slightly increase the pH value but did not improved the cement mechanical strength, however, the mechanical strength of both $CO_3Ap$ groups were significantly higher than calcium hydroxide. All three groups released calcium ions and had alkaline pH. Highest pH level, as well as calcium released level, was in the control group. Conclusion: The CAS cement had good mechanical and acceptable chemical properties for pulp capping application compared to calcium hydroxide as a gold standard. However, improvements and in vivo studies are to be carried out with the further development of this material.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.6
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• pp.29-39
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• 2007

RSA is one of the most popular public-key crypto-system in various applications. This paper addresses a high-speed RSA crypto-processor with modified radix-4 modular multiplication algorithm and Chinese Remainder Theorem(CRT) using Carry Save Adder(CSA). Our design takes 0.84M clock cycles for a 1024-bit modular exponentiation and 0.25M cycles for a 512-bit exponentiations. With 0.18um standard cell library, the processor achieves 365Kbps for a 1024-bit exponentiation and 1,233Kbps for two 512-bit exponentiations at a 300MHz clock rate.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.5
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• pp.15-25
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• 2002

In this paper a design of high performance cryptographic processor which implements AES Rijndael algorithm is described. To eliminate performance degradation due to round-key computation delay of conventional processor, the on-the-fly precomputation of round key based on modified round structure is adopted. And on-the-fly round key generator which supports 128, 192, and 256-bit key has modular structure. The designed processor has iterative structure which uses 1 clock cycle per round and supports three operation modes, such as ECB, CBC, and CTR mode which is a candidate for new AES modes of operation. The cryptographic processor designed in Verilog-HDL and synthesized using 0.251$\mu\textrm{m}$ CMOS cell library consists of about 51,000 gates. Simulation results show that the critical path delay is about 7.5ns and it can operate up to 125Mhz clock frequency at 2.5V supply. Its peak performance is about 1.45Gbps encryption or decryption rate under 128-bit key ECB mode.