• IMMUNE NETWORK
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• v.3 no.3
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• pp.188-200
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• 2003

Background: Immunization of dendritic cells (DCs) pulsed with tumor antigen can activate tumor-specific cytotoxic T lymphocytes (CTL) that are responsible for protection and regression. In this study, we examined whether the uptake of necrotic tumor cells could modulate DC phenotypes and whether the immunization of necrotic tumor cell-loaded DCs could elicit efficient tumor specific immune responses followed by a regression of established tumor burdens. Methods: We prepared necrotic tumor cell-pulsed DCs for the therapeutic vaccination and investigated their phenotypic characteristics, the immune responses induced by these DCs, and therapeutic vaccine efficacy against colon carcinoma in vivo. Several parameters including phagocytosis of tumor cells, surface antigen expression, chemokine receptor expression, IL-12 production, and NK as well as CTL activation were assessed to characterize the immune response. Results: DCs derived from mouse bone marrow efficiently phagocytosed necrotic tumor cells and after the uptake, they produced remarkably increased levels of IL-12. A decreased CCR1 and increased CCR7 expression on DCs was also observed after the tumor uptake, suggesting that antigen uptake could induce DC maturation. Furthermore, co-culturing of DCs with NK cells in vitro enhanced IL-12 production in DCs and IFN-${\gamma}$ production in NK cells, which was significantly dependent on IL-12 production and cell-to-cell contact. Immunization of necrotic tumor cell-loaded DCs induced cytotoxic T lymphocytes as well as NK activation, and protected mice against subsequent tumor challenge. In addition, intratumoral or contra-lateral immunization of these DCs not only inhibited the growth of established tumors, but also eradicated tumors in more than 60% of tumor-bearing mice. Conclusion: Our data indicate that production of IL-12, chemokine receptor expression and NK as well as CTL activation may serve as major parameters in assessing the effect of tumor cell-pulsed DC vaccine. Therefore, DCs loaded with necrotic tumor cells offer a rational strategy to treat tumors and eventually lead to prolonged survival.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.777-783
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• 2003

The mechanical properties of B$_4$C/Al composites normally depend on the species and quantity of reaction products between B$_4$C and Al and then the control of reaction products is necessary to make desirable composites for lightweight advanced or armor materials. TiB$_2$ is chemically inert with aluminum and has a lower contact angle (85$^{\circ}$ at 100$0^{\circ}C$) to liquid aluminum than B$_4$C. Thus, TiB$_2$ coating on B$_4$C may lower infiltration temperature of aluminum when the B$_4$C/Al composites is fabricated by infiltration process. In this study, the effects of TiB$_2$ on the microstructure and mechanical properties of the B$_4$C/Al composites have been investigated. TiB$_2$ coated B$_4$C powder was prepared using the sol-gel technique. It was found that the B$_4$C surface is homogeneously covered with TiB$_2$ having a particles size of 20-50 nm. While the B$_4$C/Al composites prepared by infiltration after TiB$_2$ coating had 17 wt% of unreacted Al, on the other hand, the B$_4$C/Al composites without coating included 14 wt% of Al. As a result, the composites infiltrated after the coating showed higher fracture toughness and lower hardness. This strongly suggests that TiB$_2$ not only lowers the infiltration temperature, but also inhibits the reaction between B$_4$C and Al.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.9
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• pp.1010-1019
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• 2008

In this paper, we present a noise analysis and measurement results of a bio-radar system that can detect human heartbeat and respiration signals. The noise analysis including various phase noise effects is very important in designing the bio-radar system, since the frequency difference between the received signal and local oscillator is very small and the received power is very low. All of the noise components in a bio-radar system are considered from the point of view of SNR. From this analysis, it can be concluded that the phase noise due to antenna leakage is a dominant factor and is a function of range correlation. Therefore, the phase noise component with range correlation effect, which is the most important noise contribution, is measured using the measurement setup and compared with the calculated results. From the measurement results, our measurement setup can measure a closed-in phase noise of a free-running oscillator. Based on these results, it is possible to design a 2.4 GHz bio-radar system quantitatively which has a detection range of 50 cm and low power of 1 mW without additional PLL circuits.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.632-636
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• 2005

In this work, the effect of chemical treatments on surface properties of SiC was investigated in thermal and mechanical interfacial behaviors of SiC/PMMA nanocomposites. The acid/base value, contact angles, and FT-IR analysis were performed for the study of surface characteristics of the SiC studied. The thermal stabilities of the SiC/PMMA nanocomposites were investigated by thermogravimetric analysis (TGA). Also the mechanical interfacial properties of the composites were studied in critical stress intensity factor ($K_{IC}$) and critical strain energy release rate ($G_{IC}$) measurements. As a result, the acidically treated SiC (A-SiC) had higher acid value than that of untreated SiC (V-SiC) or basically treated SiC (B-SiC). The acidic solution treatment led to an increase in surface free energy of the SiC, mainly due to the increase of its specific component. Thermal and mechanical interfacial properties of the SiC/PMMA nanocomposites, including initial decomposition temperature (IDT), $K_{IC}$, and $G_{IC}$ had been improved in the acidic treatment on SiC. This was due to the improvement in the interfacial bonding strength, resulting from the acid-base interfacial interactions between the fillers and polymeric matrix.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.561-571
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• 2006

RFID technology, as one contact-less identification technology with using electronic tag, is the field where its multiple researches have been studied. Especially, in the field of supply chain management, when it is necessary to identify a lot of objects by real-time, performance of anti-collision algorithm for multiple tag identification has an effect on performance of entire system. GEN2 is global, open, interoperability protocol for UHF RFID system, the active researches and developments are processed about it. In this paper, we introduce an anti-collision algorithm based on Slotted-ALOHA for GEN2 protocol, focus on estimating number of tags and setting number of slots and review the previous works. We propose new scheme that can estimate number of tags efficiently, and define system efficiency newly when it's used in setting number of slots. We also present result of compare and analysis with previous scheme through simulation. The proposed scheme of estimating number of tags is easy to implement, number of tags which is less than 4 times of number of slots can estimate tags efficiently, we also proved that identification efficiency based on weighted-slot distinguished with definition of previous slot efficiency can improve system efficiency.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.2
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• pp.63-67
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• 2010

The organic solar cells with Glass/ITO/PEDOT:PSS/P3HT:PCBM/Al structure were fabricated using regioregular poly (3-hexylthiophene) (P3HT) polymer:(6,6)- phenyl $C_{61}$-butyric acid methyl ester (PCBM) fullerene polymer as the bulk hetero-junction layer. The P3HT and PCBM as the electron donor and acceptor materials were spin casted on the indium tin oxide (ITO) coated glass substrates. The optimum mixing concentration ratio of photovoltaic layer was found to be P3HT:PCBM = 4:4 in wt%, indicating that the short circuit current density ($J_{SC}$), open circuit voltage ($V_{OC}$), fill factor (FF) and power conversion efficiency (PCE) values were about 4.7 $mA/cm^2$, 0.48 V, 43.1% and 0.97%, respectively. To investigate the effects of the post annealing treatment, as prepared organic solar cells were post annealed at the treatment time range from 5min to 20min at $150^{\circ}C$. $J_{SC}$ and $V_{OC}$ increased with increasing the post annealing time from 5min to 15min, which may be originated from the improvement of the light absorption coefficient of P3HT and improved ohmic contact between photo voltaic layer and Al electrode. The maximum $J_{SC},\;V_{OC}$, FF and PCE values of organic solar cell, which was post annealed for 15min at $150^{\circ}C$, were found to be about 7.8 $mA/cm^2$, 0.55 V, 47% and 2.0%, respectively.

• Journal of the Ergonomics Society of Korea
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• v.34 no.4
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• pp.313-326
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• 2015

Objective: The objective of this research is to quantitatively analyze muscle activities of arm and shoulder, according to direction in various types of one-handed manual material handling, based on surface electromyography. Background: Workers in industrial sites frequently carry out one-handed manual material handling using arm and shoulder muscles. Therefore, chronic load and accumulated fatigue occur to arm and shoulder muscles, which becomes a main cause of upper arm and shoulder musculoskeletal disorders. The shoulder muscles have widely range of motion, and complex interactions take place among various muscles including rotator cuff muscles. In this regard, research on interactions among should muscles, according to such various dynamic motions, is required. Method: Ten male subjects in their 20s participated in this research. This research considered upward, downward, leftward, rightward, forward and backward directions and fourteen muscles around arm and shoulder (biceps brachii and trapezius, etc.) as independent variables. The mean muscle activity was set as the dependent variable. This research extracted $4^{th}{\sim}7^{th}$ repetition signals according to ten times of repetitive muscle contraction, and analyzed the muscle activity concerned using the envelope detection technique. Results: The mean muscle activity of upward direction was analyzed highly statistically significant. The reason is that the effect of gravity works to arm and shoulder muscles. Also, it is conjectured that deformation of coracoacromial ligament was caused, and its contact pressure increased, due mainly to the shoulder flexion, and therefore load was analyzed high. Muscle activity was analyzed significantly low, according to concentric ballistic motion used in the concentric contraction phase by storing elastic energy in the eccentric contraction phase with a motion to bring the weight to the front of subject's body as to downward, leftward and backward directions. Because, elbow joint's flexion-extension motions mainly occurred, biceps brachii was analyzed high muscle activity as the prime mover. Conclusion: The information on the quantitative load of muscles can be applied to ergonomic work design for one-handed manual material handling to minimize muscle load. Application: This research has effectively identified muscle activity according to dynamic contraction by applying an envelope detection technique. The results can be used for ergonomic work design to minimize muscle load during the one-handed manual material handling, according to each direction. The research results are expected to be used for musculoskeletal disorder prevention and physiotherapy in the rehabilitation medical field, based on the muscle load of arm and shoulder in various directions.

• Journal of Periodontal and Implant Science
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• v.50 no.2
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• pp.121-131
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• 2020

Purpose: Dental implant-associated medication-related osteonecrosis of the jaw has been frequently reported in patients administered bisphosphonates (BPs) to prevent osteoporosis. The aim of this study was to investigate the effect of intermittent administration of parathyroid hormone (PTH) on peri-implant bone in the maxillae of ovariectomized rats systemically administered BPs. Methods: Thirty 8-week-old female Sprague-Dawley rats were randomly divided into 3 groups. The OVX-ZP group included ovariectomized rats administered 60 ㎍/kg of zoledronate once a week for 6 weeks and 30 ㎍/kg PTH after implant installation. The OVX-Z group included ovariectomized rats administered 60 ㎍/kg of zoledronate once a week for 6 weeks and saline after implant installation, and the control group included rats that underwent a sham operation and were then administered saline. Rats were sacrificed 4 weeks after implant placement for histomorphometric and micro-computed tomography (CT) analyses. Results: The average bone area percentage was greater in the OVX-ZP group than in the OVX-Z group (53.4%±4.0% vs. 28.9%±9.5%, P=0.01). The bone-to-implant contact ratio was 50.8%±1.4% in the OVX-ZP group and 16.9%±2.4% in the OVX-Z group (P=0.012). The average bone volume ratio as shown on micro-CT was 31.3%±19.8% in the OVX-ZP group and 19.4%±9.3% in the OVX-Z group (P=0.045). The OVX-ZP and OVX-Z groups displayed similar trabecular thickness (0.06±0.004 mm vs. 0.06±0.002 mm) (P>0.05) and trabecular separation (0.21±0.02 mm vs. 0.29±0.13 mm) (P>0.05). However, the number of trabeculae in the OVX-ZP group was significantly higher than that in the OVX-Z group (4.3±1.33/㎣ vs. 2.2±0.19/㎣) (P=0.024). Conclusions: The present findings indicate that intermittently-administered PTH can promote peri-implant bone formation and suggest that PTH administration may aid in effective treatment for medication-related osteonecrosis of the jaw after dental implantation.

• Tuberculosis and Respiratory Diseases
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• v.40 no.1
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• pp.29-34
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• 1993

Background: The development of the flexible fiberoptic broncoscope by Ikeda was an important technologic advance in the diagnosis and management of patients with pulmonary disease. But, cross contamination related to fiberoptic bronchoscope was reported in cases involving tubercle bacilli, MOTT and other agents. Therefore, cleaning and disinfecting of fiberoptic bronchoscope requires careful attention. Methods: From September 1991 to May 1992, medical records of all patients with positive culture for MOTT in bronchial washing specimens were reviewed. Also to evaluate bactericidal effect of 2% glutaraldehyde, culture was performed after inoculum of MOTT, Serratia marsescens and Pseudomonas aeruginosa to the disinfectant solution. Results: In 2% alkaline glutaraldehyde, MOTT was not survived only after 30 minute exposure, but P. aeruginosa and S. marsescens were rapidly inactivated with no survivors after exposure to 2% glutaraldehyde. Since vigorous mechanical cleansing and more than 30 minute of contact time within washing machine, no more outbreak was observed. Conclusions: It is also very important that bronchoscopes must be meticulously cleaned after each procedure and more than 30 minute exposure would be required for eradication of MOTT with 2% glutaraldehyde. However even the most strictly applied infection control measures cannot exclude contamination completly and clinicians have to stay alert to this possibility. Prompt detection of pseudoepidemics is possible if abrupt increase in isolation rates, especially if they involve unusual or generally nonpathogenic organisms, are readily recognized.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.2
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• pp.89-95
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• 2017

Although the global coffee market is growing every year and the demand for coffee wrapping paper is increasing accordingly, research on the effect of PE material and PP material on the coffee aroma used in the sealant layer, which will directly contact the product, is lacking. In this study, we studied the change of aroma patterns and flavor materials by adding coffee to PP and PE pouches. In addition, we observed changes in aroma patterns depending on the temperature and the presence of the deoxidizer. As a result, it was found that the PP type packaging material was slightly better than the PE type packaging material, but the performance was hardly changed by the material. Rather, the change in the aroma pattern due to temperature was dominant rather than the material. It is ideal that refrigerated distribution ($4^{\circ}C$) is the best storage temperature and sales are done within a short period of time. Among the indicators, pyridine was the most suitable material to study and there are many data about pyridine. Therefore, it is expected that the results can be derived by using pyridine.