• Bulletin of the Korean Chemical Society
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• 제26권6호
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• pp.935-938
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• 2005

Nucleophilic addition reactions of benzylamines (BA; $XC_6H_4CH_2NH_2$) to $\alpha-cyano-\beta$-phenylacrylamides (CPA; $YC_6H_4CH=C(CN)CONH_2$) have been investigated in acetonitrile at 25.0 ${^{\circ}C}$. The rate is first order with respect to BA and CPA and no base catalysis is observed. The addition of BA to CPA occurs in a single step in which the addition of BA to $C_{\beta}$ of CPA and proton transfer from BA to $C_{\alpha}$ of CPA take place concurrently with a four-membered cyclic transition state structure. The magnitude of the Hammett ($\rho_X$) and Bronsted ($\beta_X$) coefficients are rather small suggesting an early tansition state (TS). The sign and magnitude of the crossinteraction constant, $\rho_XY$ (= −D0.26), is comparable to those found in the normal bond formation processes in the $S_N2$ and addition reactions. The normal kinetic isotope effect ($k_H/k_D\;{\gt}$ 1.0) and relatively low ${\Delta}H^{\neq}$ and large negative ${\Delta}S^{\neq}$ values are also consistent with the mechanism proposed.

• 청정기술
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• 제19권1호
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• pp.59-64
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• 2013

고분자전해질 연료전지에서 사용되는 전도성 카본에 백금이 담지된 전극촉매를 콜로이드법을 이용하여 합성하였다. 콜로이드법 합성을 위한 백금 전구체로는 PSA (platinum sulfite acid)를 사용하였으며, 고가의 전구체를 대체하기 위해 CPA (chloroplatinic acid)를 사용하여 합성하였다. PSA를 전구체로 하여 제조한 전극촉매는 10~40 wt% 담지량에서 3.5 nm 이하의 백금 입자크기와 90% 이상의 백금 담지수율을 보였다. CPA를 전구체로 사용한 경우에는 10~40 wt% 담지량에서 4.4 nm 이하의 백금 입자 크기를 보였으며 담지수율은 80% 이상이었다. 제조한 20 wt% Pt/VXC72 전극촉매로 MEA (membrane electrode assembly)를 제조하여 I-V 곡선을 측정하였으며, 제조한 전극촉매를 이용한 막전극접합체는 상용전극촉매를 사용한 경우와 동등한 성능을 보였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2020년도 추계학술대회
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• pp.39-41
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• 2020

충돌 회피를 위한 위험도 평가에서 CPA 계산은 핵심 요소이며, AIS의 도입 이후 AIS 정보를 이용한 CPA 계산이 필수적으로 활용되고 있다. 본 논문에서는 CPA 계산에 이용되는 AIS 정보와 실제 특성을 확인하고, 선박 위치 추정에 관련된 선행 연구들을 분석하며, 이를 가상 디지털 항로 표지 서비스에 적용할 방안을 강구한다, P. Last 등의 연구는 ROT의 중요성을 강조하고 있으나, 대부분의 선박이 필요로 하는 정확한 ROT 값을 전송하지 못하고 있는 상황을 확인했고, Ling-Zhi Sang 등의 연구는 4가지 요소를 반영한 간단한 식으로 구현하여 전 해역의 데이터로 비교한 결과 2가지 요소만을 적용한 방법에 대한 정확도의 향상을 확인할 수 없었다.

• International Journal of Computer Science & Network Security
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• 제21권4호
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• pp.264-271
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• 2021

From an information security perspective, protecting sensitive data requires utilizing algorithms which resist theoretical attacks. However, treating an algorithm in a purely mathematical fashion or in other words abstracting away from its physical (hardware or software) implementation opens the door to various real-world security threats. In the modern age of electronics, cryptanalysis attempts to reveal secret information based on cryptosystem physical properties, rather than exploiting the theoretical weaknesses in the implemented cryptographic algorithm. The correlation power attack (CPA) is a Side-Channel Analysis attack used to reveal sensitive information based on the power leakages of a device. In this paper, we present a power Hacking technique to demonstrate how a power analysis can be exploited to reveal the secret information in AES crypto-core. In the proposed case study, we explain the main techniques that can break the security of the considered crypto-core by using CPA attack. Using two cryptographic devices, FPGA and 8051 microcontrollers, the experimental attack procedure shows that the AES hardware implementation has better resistance against power attack compared to the software one. On the other hand, we remark that the efficiency of CPA attack depends statistically on the implementation and the power model used for the power prediction.

• 한국정보과학회논문지:시스템및이론
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• 제33권4호
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• pp.223-230
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• 2006

가산기를 이용하여 몽고메리 곱셈을 수행하는 모듈라 곱셈기를 구현하는 방법은 선택한 가산기의 종류에 따라 달라진다. 가산기로 CPA를 사용하는 경우는 캐리 전파 문제가 발생되며, CSA를 사용하는 경우는 최종 결과 보정이 요구된다. 다정도 CSA는 CSA와 CPA를 접목함으로써 이 두 문제를 동시에 해결한 방식이다. 본 논문에서는 기존의 다정도 CSA의 캐리 체인 구조를 변경함으로써, 하드웨어 자원과 수행시간을 동시에 감소시킨 새로운 방식을 제안하였다. 결과적으로, 모듈라 곱셈기를 반복 사용하여 큰 정수의 곱셈과 멱승을 수행하는 모듈을 기존의 방식보다 더 빠르고 더 작게 구현할 수 있다.

• Journal of Korean Neurosurgical Society
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• 제60권3호
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• pp.380-384
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• 2017

Glioblastoma multiforme (GBM) is located most frequently in the cerebral hemispheres. Glioblastoma presenting as an extraaxial mass of cerebellopontine angle (CPA) is very rare in adults. We report a rare case of GBM arising in the CPA. The patient was a 71-year-old female, who complained of progressive gait disturbance and poor memory. Initial magnetic resonance imaging (MRI) revealed a $1.4{\times}1.3cm$ mass in the left CPA, with broad base to the petrous bone, showing homogenous enhancement. Follow-up MRI showed a rapid increase in size of mass ($2.7{\times}2.2cm$) with a necrotic portion. A stereotactic biopsy was done under the guidance of navigation system, and the histopathologic diagnosis was GBM, World Heath Organization grade IV. Further surgical resection was not performed considering her general condition, and the patient underwent concurrent chemotherapy with radiation therapy. Although rare, the possibility of glioblastoma should be included in the differential diagnosis of atypical CPA tumor.

• Journal of Ginseng Research
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• 제24권4호
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• pp.157-161
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• 2000

인삼배양세포로부터 항산화 물질 고함유 세포주를 선발하기 위하여 인삼육성계통별로 배양기 내에서 callus를 유기하여 callus생장에 미치는 식물호르몬의 영향을 조사하였고, 페놀성 화합물 및 항산화 물질의 함량을 조사함으로써 생리활성물질 고함유 세포주를 선발하고자 하였다. callus 생장은 2mg/L의 CPA를 함유한 MS기본배지에서 가장 높았고, CPA혼합배지로부터 CPA혼합배지로 계대배양할 때 가장 \ulcorner효과적이었으며 생장률은 계대시 Ig/flask의 callus를 접종할 때 가장 효율적이었다. 생리활성물질인 페놀성 화합물의 함량은 공시계통 callus가 재배 인삼뿌리보다 높았다. 특히 계통번호20601은 페놀성 화합물의 함량과 항산화 활성에서 가장 높았으며 Callus의 생장도 매우 양호하였다. 또한 페놀성 화합물의 TLC pattern은 재배 인삼근과 비슷하였으나 함량은 재배 인삼근에 비해 표준품인 caffeic acid의 위치에 더 많은 페놀성 물질이 분포하였다.

• Nutrition Research and Practice
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• 제17권2호
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• pp.206-217
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• 2023

BACKGROUND/OBJECTIVES: The immunomodulatory effect of Platycodon grandiflorum (PG) has been reported, but studies on its mechanism are still lacking. This study was undertaken to confirm whether the hydrolyzed and fermented PG extract (HFPGE) obtained by adding hydrolysis and fermentation to the extraction process has an immune-enhancing effect in the in vivo system. MATERIALS/METHODS: Five-week-old BALB/c mice were divided into 4 groups: normal control group (NOR), control group (CON), 150 mg/kg body weight (BW)/day HFPGE-treated group (T150), and 300 mg/kg BW/day HFPGE-treated group (T300). The mice were administered HFPGE for 4 weeks and intraperitoneally injected with cyclophosphamide (CPA, 80 mg/kg BW/day) on day 6, 7, and 8, respectively, to induce immunosuppression. The levels of immunoglobulins (Igs) and cytokines were measured in the serum. In splenocytes, proliferation and cytokine levels were measured. RESULTS: Serum IgA, IgG, and IgM levels were observed to decrease after CPA treatment, which was recovered by HFPGE administration. The levels of serum interleukin (IL)-12, tumor necrosis factor (TNF)-α, IL-8, and transforming growth factor (TGF)-β were also decreased after exposure to CPA but increased after HFPGE administration. Decreased splenocyte proliferation was seen in CPA-treated mice, but was observed to increase in the T150 and T300 groups as compared to the NOR group. Compared to the CON group, splenocyte proliferation stimulated with concanavalin A (ConA) or lipopolysaccharide (LPS) in the HFPGE-treated groups was significantly increased. The cytokines secreted by ConA-stimulated splenocytes (IL-2, IL-12, interferon-γ, TNF-α) were increased in the T150 and T300 groups, and cytokines secreted by LPS-stimulated splenocytes (IL-4, IL-8, TGF-β) were also increased by HFPGE administration. CONCLUSION: These results suggest that HFPGE stimulates the immunity in immunosuppressed conditions, thereby enhancing the immune response. Therefore, it is expected that HFPGE has the potential to be used as functional food and medicine for immune recovery in various immunocompromised situations.

• 정보보호학회논문지
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• 제33권1호
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• pp.33-43
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• 2023

최근 미국의 국립표준기술연구소(NIST: National Institute of Standards and Technology)는 양자 내성 암호(PQC: Post-Quantum Cryptography, 이하 PQC) 표준화 사업을 진행하여 4개의 표준 암호 알고리즘을 발표하였다. 본 논문에서는 전자서명 분야에서 표준화가 확정된 CRYSTALS-Dilithium 알고리즘을 이용하여 서명을 생성하는 과정에서 동작하는 다항식 계수별 곱셈 알고리즘을 대상으로 비프로파일링 기반 전력 분석 공격인 CPA(Correlation Power Analysis)나 DDLA(Differential Deep Learning Analysis) 공격에 의해 개인 키가 노출될 수 있음을 실험을 통해 증명한다. ARM-Cortex-M4 코어에 알고리즘을 탑재하여 실험결과, CPA 공격과 DDLA 공격에서 개인 키 계수를 복구할 수 있음을 확인하였다. 특히 DDLA 공격에서 StandardScaler 전처리 및 연속 웨이블릿 변환을 적용한 전력 파형을 이용하였을 때 공격에 필요한 최소 전력 파형의 개수가 줄어들고 NMM(Normalized Maximum Margin) 값이 약 3배 증가하여 공격 성능이 크게 향상됨을 확인하였다.

• 대한수의학회지
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• 제36권4호
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• pp.873-886
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• 1996

For better understanding the interrelationship of hemorrhage and aggregation mechanism, cyclopiazonic acid(CPA) known as promoting the aggregation of platelet, aflatoxin $B_1(AFB_1)$ inhibiting platelet aggregation were used as toxic mycotoxins in these studies. In order to investigate the potential role of prostaglandin metabolism on the platelet aggregation, a variety of prostaglandin metabolites such as $PGF_{2{\alpha}}$, $PGE_2$ and $TXB_2$ were measured in homogenized rabbit platelets by TLC and LSC. And the role of $Ca^{{+}{+}}$ on the platelet aggregation was investigated by flow cytometer. Finally, the morphological effects of mycotoxins on platelet were determined by transmission electron microscope. The results and conclusions obtained from these studies are: 1) CPA induced no changes but $AFB_1$ increased $PGE_2$ and $TXB_2$. 2) CPA promoted ADP, collagen, thrombin, A.A., and PAF-induced $Ca^{{+}{+}}$ release. $AFB_1$, however, decreased $Ca^{{+}{+}}$ level except collagen-induced $Ca^{{+}{+}}$ release. When the calcium blocker, verapamil, was used, CPA decreased thrombin-induced $Ca^{{+}{+}}$ release and increased collagen, ADP, PAF and A.A.-induced $Ca^{{+}{+}}$ release. $AFB_1$ in contrast decreased the all factors induced $Ca^{{+}{+}}$ release. 3) $AFB_1$ did not induce any ultrastructural changes except large vacuole formation in a few platelets. And CPA also did not induce any changes except moderate shape change, indicator of platelet activation. In conclusion, CPA promoted platelet aggregation by the increases of $Ca^{{+}{+}}$ release but had no changes in A.A. metabolites. Antiaggregating effects of $AFB_1$ may be due to decreases of $Ca^{{+}{+}}$ release and increases of $PGE_2$ and $PGF_{2{\alpha}}$ formation. These data provide the basis for the future study of mobilization and function of $Ca^{{+}{+}}$ in platelet aggregation.