• Journal of Pharmaceutical Investigation
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• 제34권5호
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• pp.363-368
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• 2004

In order to investigate the effect of bovine serum albumin (BSA), as a pore former, on the controlled release of an antibiotic from a biodegradable polymeric device, polycaprolactone (PCL)-cefadroxil matrices were prepared by the solvent casting method. The amount of cefadroxil released from various formulations at $37^{\circ}C$ was measured by HPLC. The duration of antimicrobial activity of matrices against S. aureus was evaluated by measuring the diameters of the inhibition zone. The morphology of the matrices was investigated by scanning electron microscopy (SEM). The release rate and extent of cefadroxil from PCL matrix increased as the loading dose and particle size of BSA/cefadroxil mixture powder increased. Cefadroxil released from the matrix exhibited antibacterial activity for up to 4 days. SEM of the cross-section of matrix showed the typical channel formation after 3 days of release study. Thus, a biodegradable polymeric matrix loaded with antibiotic/BSA mixture can effectively prevent bacterial infection on its surface, thereby bringing about an enhancement of biocompatibility of biomaterials.

• 전자통신동향분석
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• 제5권1호
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• pp.55-70
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• 1990

SIMOX SOI is known to be one of the most useful technologies for fabrications of new generation ULSI devices. This paper describes the current status of SIMOX SOI technology for ULSI applications. The SIMOX wafer is vertically composed of buried oxide layer and silicon epitaxial layer on top of the silicon substrate. The buried oxide layer is used for the vertical isolation of devices The oxide layer is formed by high energy ion implantation of high dose oxygen into the silicon wafer, followed by high temperature annealing. SIMOX-based CMOS fabrication is transparent to the conventional IC processing steps without well formation. Furthermore, thin film CMOX/SIMOX can overcome the technological limitations which encountered in submicron bulk-based CMOS devices, i.e., soft-error rate, subthreshold slope, threshold voltage roll-off, and hot electron degradation can be improved. SIMOX-based bipolar devices are expected to have high density which comparable to the CMOX circuits. Radiation hardness properties of SIMOX SOI extend its application fields to space and military devices, since military ICs should be operational in radiation-hardened and harsh environments. The cost of SIMOX wafer preparation is high at present, but it is expected to reduce as volume increases. Recent studies about SIMOX SOI technology have demonstrated that the performance of the SIMOX-based submicron devices is superior to the circuits using the bulk silicon.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.220-220
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• 1999

In plasma source ion implantation, the target is immersed in the plasma and repetitively biased by negative high voltage pulses to implant the extracted ions from plasma into the surface of the target material. In this way, the problems of line-of-sight implantation in ion-beam ion implantation technique can be effectively solved. In addition, the high dose rate and simplicity of the equipment enable the ion implantation a commercially affordable process. In this work, plasma source ion implantation technique was used to improve the wear resistance of Co-cemented WC. which has been extensively used for high speed tools. Nitrogen and carbon ions were implanted using the pulse bias of -602kV, 25 sec and at various implantation conditions. The implanted samples were examined using scanning Auger electron spectroscopy and XPS to investigate the depth distributions of implanted ions and to reveal the chemical state change due to the ion implantation. The implanted ions were found to have penetrated to the depth of 3000$\AA$. The wear resistance of the implanted samples was measured using pin-on-disc wear tester and the wear tracks were examined with alpha-step profilometer.

• Membrane and Water Treatment
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• 제13권5호
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• pp.209-217
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• 2022

In the present research, Ficus religiosa Bark (FRB) is used as an adsorbent for the removal of heavy metal Cr (VI) ions. This Ficus religiosa Bark was characterized by Scanning Electron Microscope, Fourier transform infrared Spectroscopy, Thermo Gravimetric Analyzer and the results showed that activated adsorbent have high adsorption capacity and withstand even in high temperature. Batch and Continuous experiments were conducted to determine the effect of various parameters such as pH, contact time, adsorbent dose and initial metal concentration. The biosorption followed pseudo first order kinetic model. The adsorption isotherms of Cr (VI) on Ficus religiosa fitted well with the Temkin model. In Batch study, maximum biosorption capacity of Cr (VI) was found to be 37.97 mg g^-1 (at optimal pH of 2, adsorbent dosage of 0.3 grams and concentration of Cr (VI) is100 mg L^-1). The Continuous mode of study shows that 97% of Cr (VI) ion removal at a flow rate of 15 ml min^-1. From the results, selected Ficus religiosa Bark has the higher adsorption capacity for the removal of Cr (VI) ions from wastewater.

• Korean Chemical Engineering Research
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• 제52권1호
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• pp.113-118
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• 2014

케냐프 코어 전처리를 위하여 전자선 조사와 물찜이 결합된 복합 전처리공정에 대해 연구하였다. 각 시료는 50에서 1,000 kGy까지의 선량으로 조사한 후, 오토클레이브를 이용하여 $120^{\circ}C$에서 5시간 동안 물찜처리를 하였다. 적외선 분광기와 X선 회절 분석기를 사용하여 전처리 되지 않은 시료와 전처리된 시료의 분자 구조와 결정도 변화를 분석하였다. 전처리 되지 않은 시료의 결정화도 지수는 50.6%에서 500 kGy 조사된 시료는 55.0%로 증가함을 알 수 있었다. 그 다음, 전처리된 시료에 비활성도 70 FPU/mL, 40 CBU/mL의 효소를 주입하여 생산된 단당류 총합으로 당화율을 구하였다. 이 때 효소 가수분해 시간은 24, 48, 72시간으로 하였다. 500 kGy로 조사된 시료의 72 시간 가수분해 후 당화율은 83.9%로 가장 높게 나타났고, 전처리된 시료의 당화율은 조사량 증가에 따라 100 kGy에서 50.8%, 200 kGy에서 58.6%, 300 kGy에서 67.9%로 각각 증가하였다.

• 대한두경부종양학회지
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• 제16권2호
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• pp.167-171
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• 2000

Objectives: To compare the outcomes of treatment with a focus on the effectiveness of the two primary techniques of radiation used for treating parotid gland malignancies. Materials and Methods: A retrospective analysis of 70 patients with parotid gland cancer treated between 1981-1997. Radiation was delivered through an ipsilateral field of high energy electron and photon in 37 patients(52.9%). Two wedge paired photon was used to treat in 33 patients(47.1%). The median dose was 60 Gy, typically delivered at 1.8-2.0Gy per fraction. The median follow-up times for surviving patients was 60 months. Results: The overall and disease free 5 year survival rates were 71.6% and 69.5%, respectively. Wedge paired photon and photon-electron treatment disease tree 5 year survival rates were 61.1% and 80.5%, respectively. Overall local failure rate was 18.6%. Local failure rate of wedge paired photon technique was higher than that of mixed beam technique. Late complication rate was 37.1%, but most of them were mild grade. Conclusion: Techniques of radiation were associated with local control. The technique of using an ipsilateral field encompassing the parotid bed and treated with high energy electrons often mixed photons was effective with minimal severe late toxicity. To irradiate deep sited tumors, we consider 3-D conformal treatment plan for well encompassing the target volume.

• Radiation Oncology Journal
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• 제21권1호
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• pp.75-81
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• 2003

목적 : 방사선에 의해 유도되는 림프구의 아포프토시스를 정상 성인의 말초 혈액에서 유세포계측검사로 측정할 때 소량의 혈액으로도 검사가 가능한가를 알아보고 선량 증가와 방사선조사 후 시간 경과에 따른 반응 정도를 알아보고자 본 연구를 시행하였다. 대상 및 방법 : 건강한 성인 남녀 11명을 연구 대상으로 하여 말초혈액 10 mL에서 림프구를 분리하고 이를 각각 15개로 나누어서 실험하였다. 선형가속기를 이용하여 0.5, 1, 2, 5 GV의 방사선을 조사한 후 24, 48, 72시간 동안 배양하였다. 림프구의 아포프토시스를 정량적으로 측정하기 위해 유세포계측검사를 시행하였으며, 별도로 DNA fragmentation assay와 전자현미경검사를 이용하여 아포프토시스 소견을 추가로 관찰하였다. 결과 : 방사선을 조사하지 않았을 때의 자발성 아포프토시스율(%)은 배양 후 24, 48, 72시간이 경과함에 따라 증가하는 소견을 보였다(1.761${\pm}$0.16), 3.563${\pm}$0.564, 11.098${\pm}$2.8491. 또한 0.5, 1, 2, 5 eV의 방사선을 조사하여 24, 48, 72 시간 동안 배양한 후 측정한 아포프토시스율(%)은 선량 증가와 방사선조사 후 시간 경과에 따라 점차 증가하였다 방사선조사 후 24시간 후에 0.5~1, 1~2, 2~5 Gy구간의 아포프토시스율의 증가는 비교적 저 선량 영역인 0.5~1 1~2 Gy에서 2~5 Gy 구간보다 더 큰 기울기를 보였고, 48, 72시간 후에도 0.5~l Gy구간에서 가장 큰 기울기를 보였다.결론 : 유세포계측검사는 10 mL의 혈액으로 15개의 검사 결과를 낼 수 있었으므로 한 검사당 1 mL 미만의 혈액으로도 충분히 검사할 수 있겠으며, 방사선량 증가에 따라 반응의 정도도 증가하였으며, 아포프토시스 관찰 시기는 혈액 채취 후 24시간이나 48시간 후가 적절하다고 사료된다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권2호
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• pp.625-631
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• 2012

In order to investigate whether SKI-II could reverse drug resistance and its possible mechanisms, we treated SGC7901/DDP cells with SKI-II or SKI-II in combination with DDP. Then cell growth, apoptosis, micromorphological changes, and expression of SphK1, P-gp, NF-${\kappa}B$, Bcl-2 and Bax were assessed by MTT assay, flow cytometry, electron microscopy, immunocytochemistry and Western blot assay respectively. SGC7901/DDP cells were insensitive to cisplatin 2.5mg/L, but when pretreated with SKI-II, their proliferation was inhibited by cisplatin 2.5mg/L significantly, the inhibition rate increasing with time and dose. The apoptosis rate was also significantly elevated. Expression of SphK1 and P-gp was decreased significantly, Pearson correlation analysis showing significant correlation between the two (r=0.595, P<0.01). Expression of NF-${\kappa}B$ and Bcl-2 was decreased significantly,while that of Bax was increased, compared to the control group. There were significant correlations between SphK1 and NF-${\kappa}B$(r=0.723, P<0.01), NF-${\kappa}B$ and Bcl-2(r=0.768, P<0.01). All these data indicated that SKI-II could reverse drug resistance of SGC7901/DDP to cisplatin by down-regulating expression of P-gp and up-regulating apoptosis through down-regulation of SphK1. The increased apoptotic sensitivity of SGC7901/DDP to cisplatin was due to the decreasing proportion of Bcl-2/Bax via down-regulating NF-${\kappa}B$.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.755-760
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• 2019

Compound samples based on the mineral-like magnesium potassium phosphate matrix $MgKPO_4{\times}6H_2O$ were synthesized by solidification of high level waste surrogate. Phase composition and structure of synthesized samples were studied by XRD and SEM methods. Compressive strength of the compounds is $12{\pm}3MPa$. Coefficient of thermal expansion of the samples in the range $250-550^{\circ}C$ is $(11.6{\pm}0.3){\times}10^{-6}1/^{\circ}C$, and coefficient of thermal conductivity in the range $20-500^{\circ}C$ is $0.5W/(m{\times}K)$. Differential leaching rate of elements from the compound, $g/(cm^2{\times}day)$: $Mg-6.7{\times}10^{-6}$, $K-3.0{\times}10^{-4}$, $P-1.2{\times}10^{-4}$, $^{137}Cs-4.6{\times}10^{-7}$; $^{90}Sr-9.6{\times}10^{-7}$; $^{239}Pu-3.7{\times}10^{-9}$, $^{241}Am-9.6{\times}10^{-10}$. Leaching mechanism of radionuclides from the samples at the first 1-2 weeks of the leaching test is determined by dissolution ($^{137}Cs$), wash off ($^{90}Sr$) or diffusion ($^{239}Pu$ and $^{241}Am$) from the compound surface, and when the tests continue to 90-91 days - by surface layer depletion of compound. Since the composition and physico-chemical properties of the compound after irradiation with an electron beam (absorbed dose of 1 MGy) are constant the radiation resistance of compound was established.

• 대한방사선치료학회지
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• 제31권1호
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• pp.57-65
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• 2019

목 적: 전자선 치료에서 저 용융점 납합금과 순수 납을 이용한 차폐 시 두께증가에 따른 블록 가장자리의 산란선 영향을 알아보고자 한다. 대상 및 방법: $10{\times}10cm^2$ 어플리케이터의 Insert Frame 절반을 차폐하도록 블록을 제작하였고, 두께는 각 재질당 3, 5, 10, 15, 20 (mm)로 하였다. 공통 조건을 에너지 6 MeV, 선량률 300 MU/Min, 갠트리 각도 0, 부여선량 100 MU으로 설정하였고, 블록의 위치와 측정점의 위치, 블록재질을 각각 달리하여 블록 두께증가에 따른 상대적인 산란비율을 평행평판형 전리함과 고체팬텀으로 측정하였다. 결 과: (측정 깊이 / 블록 위치 / 블록 재질)이 (표면 / 어플리케이터 / 순수 납)일 때 블록 두께가 3, 5, 10, 15, 20 (mm) 순으로 증가함에 따라 상대선량은 15.33 nC, 15.28 nC, 15.08 nC, 15.05 nC, 15.07 nC로 측정되었다. (표면 / 어플리케이터 / 합금 납)일 때 15.19 nC, 15.25 nC, 15.15 nC, 14.96 nC, 15.15 nC로 측정되었다. (표면 / 팬텀 위 / 순수 납)일 때 15.62 nC, 15.59 nC, 15.53 nC, 15.48 nC, 15.34 nC로 측정되었다. (표면 / 팬텀 위 / 합금 납)일 때 15.56 nC, 15.55 nC, 15.51 nC, 15.42 nC, 15.39 nC로 측정되었다. (심부 / 어플리케이터 / 순수 납)일 때 16.70 nC, 16.84 nC, 16.72 nC, 16.88 nC, 16.90 nC로 측정되었다. (심부 / 어플리케이터 / 합금 납)일 때 16.83 nC, 17.12 nC, 16.89 nC, 16.77 nC, 16.52 nC로 측정되었다. (심부 / 팬텀 위 / 순수 납)일 때 17.41 nC, 17.45 nC, 17.34 nC, 17.42 nC, 17.25 nC로 측정되었다. (심부 / 팬텀 위 / 합금 납)일 때 17.45 nC, 17.44 nC, 17.47 nC, 17.43 nC, 17.35 nC로 측정되었다. 결 론: 차폐블록을 이용하여 전자선 치료를 진행할 때 블록위치는 환자 체표면보다는 어플리케이터에 삽입하고 두께는 각 사용 에너지에 해당되는 최소 적정차폐두께로 제작해야 한다. 또한 블록 가장자리 경계선으로부터 떨어진 거리에 따라 변화하는 산란선의 영향을 충분히 고려하여 치료를 시행하는 것이 바람직하다고 사료된다.