• 한국포장학회지
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• 제19권2호
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• pp.61-65
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• 2013

Modified atmosphere (MA) of reduced $O_2$ and elevated $CO_2$ concentrations has been used for keeping the quality of fresh produce and extending the shelf life. As a way to attain the beneficial MA package around the produce, a gas diffusion tube or perforation can be attached onto the container and controlled on real time in its opening/closing responding to $O_2$ and $CO_2$ concentrations measured by gas sensors. The timely-controlled opening of the gas diffusion tube can work in harmony with the produce respiration and help to create the desired MA. By use of the mathematical modeling, the effect of tube dimension on the controlled container atmosphere was figured out in this study. Spinach and king oyster mushroom were used as typical commodities for designing the model container system (0.35 and 0.9 kg in 13 L, respectively) because of their respiration characteristics and the optimal MA condition ($O_2$ 7~10%/$CO_2$ 5~10% for spinach; $O_2$ 2~5%/$CO_2$ 10~15% for mushroom). With a control logic for the gas composition to stay as close as possible to optimum MA window without invading injurious low $O_2$ and/or high $CO_2$ concentrations, the atmosphere of the sensor-controlled container could stay at its lower $O_2$ boundary or upper $CO_2$ limit under certain tube dimensional conditions. There were found to be the ranges of the tube diameter and length allowing the beneficial MA. The desired range of the tube dimension for spinach consisted of combinations of larger diameter and shorter length in the window of 0.3~2 cm diameter and 0.2~10 cm length. Similarly, that for king oyster mushroom was combinations of larger diameter and shorter length in the window of 0.9~2 cm diameter and 0.2~3 cm in length. Clear picture on generally affordable tube dimension range may be formulated by further study on a wide variety of commodity and pack conditions.

• The Journal of Advanced Prosthodontics
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• 제8권4호
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• pp.285-289
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• 2016

PURPOSE. This study evaluated the effect of chemical surface treatment using methyl formate-methyl acetate (MF-MA) solution on the tensile bond strength between acrylic denture teeth and auto-polymerized acrylic resin. MATERIALS AND METHODS. Seventy maxillary central incisor acrylic denture teeth for each of three different brands (Yamahachi New Ace; Major Dent; Cosmo HXL) were embedded with incisal edge downwards in auto-polymerized resin in polyethylene pipes and ground with silicone carbide paper on their ridge lap surfaces. The teeth of each brand were divided into seven groups (n=10): no surface treatment (control group), MF-MA solution at a ratio of 25:75 (v/v) for 15 seconds, 30 seconds, 60 seconds, 120 seconds, 180 seconds, and MMA for 180 seconds. Auto-polymerized acrylic resin (Unifast Trad) was applied to the ground surface and polymerized in a pressure cooker. A tensile strength test was performed with a universal testing machine. Statistical analysis of the results was performed using two-way analysis of variance (ANOVA) and post-hoc Dunnett T3 test (${\alpha}$=.05). RESULTS. The surface treatment groups had significantly higher mean tensile bond strengths compared with the control group (P<.05) when compared within the same brand. Among the surface treatment groups of each brand, there were no significantly different tensile bond strengths between the MF-MA groups and the MMA 180 second group (P>.05), except for the Yamahachi New Ace MF-MA 180-second group (P<.05). CONCLUSION. 15-second MF-MA solution can be an alternative chemical surface treatment for repairing a denture base and rebonding acrylic denture teeth with auto-polymerized acrylic resin, for both conventional and cross-linked teeth.

• 한국발생생물학회지:발생과생식
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• 제27권3호
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• pp.149-157
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• 2023

We investigated the involvement of autophagy with steroidogenesis in testicular Leydig cells. Human chorionic gonadotropin (hCG)-stimulated T production in Leydig cells was not remarkably altered in the presence of an autophagy inhibitor 3-methyladenine (3-MA). Although pretreatment with 3-MA demonstrated a tendency to decrease hCG-induced T production, the differences were significant only at a higher time point of 24 h following hCG. Microtubule associated protein light chain 3 (LC3)-II was detectable in the control cells in all the experiments. The hCG-induced increase in steroidogenic acute regulatory protein (StAR) and cytochrome P450 side chain cleave (P450scc) protein levels were not significantly altered by 3-MA. Leydig cells isolated from immature rat testes 12 h following hCG treatment showed relatively increased levels of LC3-II protein compared to the control group. Furthermore, LC3-II levels shown in these cells reached almost the identical to those from normal adult testes. However, LC3-II protein levels were almost comparable or even slightly lower than the controls at 48 h following hCG. Expression of StAR and P450scc was upregulated at both 12 and 48 h after hCG. We also used MA-10 cells, the mouse Leydig cell line, in this experiment. When dibutyryl cyclic-AMP was treated with MA-10 cells, P4 levels were significantly increased in the cell culture medium. However, P4 levels tended to decrease in the presence of 3-MA, but the difference was not statistically significant. This was consistent with the results of the rat Leydig cell experiments. Together, we believe that although autophagy participates in steroidogenesis and enhances steroidogenic efficacy of Leydig cells, it may not be a decisive cellular process for steroidogenesis, specifically in the mature Leydig cells.

• Structural Engineering and Mechanics
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• 제10권6호
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• pp.545-559
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• 2000

A Wind and Structural Health Monitoring System (WASHMS) has been installed in the Tsing Ma suspension Bridge in Hong Kong with one of the objectives being the verification of analytical processes used in wind-resistant design. On 2 August 1997, Typhoon Victor just crossed over the Bridge and the WASHMS timely recorded both wind and structural response. The measurement data are analysed in this paper to obtain the mean wind speed, mean wind direction, mean wind inclination, turbulence intensity, integral scale, gust factor, wind spectrum, and the acceleration response and natural frequency of the Bridge. It is found that some features of wind structure and bridge response are difficult to be considered in the currently used analytical process for predicting buffeting response of long suspension bridges, for the Bridge is surrounded by a complex topography and the wind direction of Typhoon Victor changes during its crossing. It seems to be necessary to improve the prediction model so that a reasonable comparison can be performed between the measurement and prediction for long suspension bridges in typhoon prone regions.

• Journal of Animal Science and Technology
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• 제62권5호
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• pp.730-740
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• 2020

This feeding trial was conducted to investigate the effects of Mentha arvensis (MA) and Geranium thunbergii (GT) in drinking water on physicochemical attributes, sensory qualities, proximate analysis and oxidative stability of broiler leg meat. One hundred and twenty broiler chicks were assigned to 1 of 4 dietary treatments for 5 weeks. The dietary treatments were 1) control, 2) T1 (0.1% 1 MA:1 GT), 3) T2 (0.1% 1 MA:4 GT), 4) T3 (0.1% 4 MA: 1 GT). The water holding capacity and cooking loss were improved (p < 0.05) in T2 and T3. The flavor, texture and acceptability of leg meat by consumers were significantly increased in T2 relative to the control (p < 0.05). The crude protein content was increased in T3 while the crude fat decreased in T2 (p < 0.05). Moreover, broilers supplemented with plant extracts had the lowest leg meat TBARS (thiobarbituric acid reactive substances) values after 2 weeks of storage as compared with the control. Total phenolic contents and 1-1-diphenyl 2 picrylhydrazyl (DPPH) activity were also better in the T2 group (p < 0.05) compared with the control, whereas 2,2-Azinobis-3 ethytlbenzothiazoline-6-sulfonic acid (ABTS⁺) remained unaffected. Overall, these results demonstrate that broiler drinking water with the inclusion of plant extract combination can be used to enhance the oxidative stability, shelf life and quality characteristics of broiler leg meat without compromising the growth performance.

• Structural Engineering and Mechanics
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• 제15권2호
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• pp.239-248
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• 2003

The dynamic response analysis of closed loop control system based on probability for the intelligent truss structures with random parameters is presented. The expressions of numerical characteristics of structural dynamic response of closed loop control system are derived by means of the mode superposition method, in which the randomness of physical parameters of structural materials, geometric dimensions of active bars and passive bars, applied loads and control forces are considered simultaneously. The influences of the randomness of them on structural dynamic response are inspected by several engineering examples and some significant conclusions are obtained.

• Asian Pacific Journal of Cancer Prevention
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• 제15권23호
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• pp.10165-10169
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• 2015

Background: Megestrol acetate (MA) is a steroid origin medicine often used for control of cachexia in oncologic palliative care. Thrombosis is a common problem in oncology patients. One question is whether MA can cause thrombosis. This retrospective, registry-based analysis was therefore conducted to assess thrombotic processes in oncology patients using MA concurrent with chemotherapy. Materials and Methods: Data on oncology patients at the metastatic stage using MA were obtained from the archives of our center. Outcomes of patients were evaluated for thromboembolic events (VTEs) during treatment. Results: Ninety-seven oncology patients with a median age of 62 (33-84) years were included. During the median follow-up of 17 months, 58 (59.8%) died leaving 39 (31.2%) still alive. Median overall survival (OS) was 19 months (6-180). Mean time of MA use was 8.69 months(${\pm}3.53$), with a median dose of 160mg (range 160-480mg). Eleven VTEs were detected after MA use, 4 of these in pancreatic cancer cases. The patients with thrombosis non-significantly had worse OS, than those without thrombosis (p=0.106). Conclusions: This trial revealed that the 11.3% of all patients developed thrombosis,who had been treated with MA and chemotherapy concomittantly. There was no statistically significant difference regarding to occurrence of thrombotic process, among the patients receiving different chemotherapy regimens with MA concomittantly. Pancreatic cancer seemed to be related to thrombosis rather than MA use.

• 한국포장학회지
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• 제19권3호
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• pp.119-123
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• 2013

기체확산 튜브를 부착한 신선 농산물 용기에서 적정 변형기체(modified atmosphere, MA)를 형성하기 위하여 산소 농도에 따라 실시간적으로 반응하여 튜브 개폐가 이루어지는 제어 logic을 개발하고 그 유효성을 검증하였다. 본 연구는 이전의 연구에서 이루어진 $O_2$ 및 $CO_2$ 센서 모두를 이용하여 제어하는 logic의 단순화를 시도한 것으로 7~10%의 $O_2$, 5~10%의 $CO_2$ 농도를 적정 MA로 갖는 시금치를 담은 용기 시스템에 대해서 $10^{\circ}C$에서 실험적으로 개발된 제어 logic의 효과를 검증하였다. $[O_2]+[CO_2]$=21%의 가정된 관계에 기반하여 $O_2$ 농도 제어점을 $CO_2$ 농도 허용 상한값(10%)에 상당하는 11%로 설정하여 제어한 결과 $CO_2$ 농도가 허용상한치 10% 바로 이하에 머무는 것으로 확인되었다. $O_2$ 농도 제어점은 품목의 $O_2/CO_2$의 MA 요구도에 따라 $O_2$ 하한값 자체 혹은 조정된 하한값으로 둘 수 있다. 산소 센서만을 사용한 개발 제어 logic은 11%의 평형 $O_2$ 농도와 8~9%의 $CO_2$ 농도를 유지하였고, 이는 $O_2$ 및 $CO_2$ 센서 모두를 사용한 제어의 조건에서 9~10%의 평형 $O_2$ 농도와 10%의 $CO_2$ 농도를 유지한 것과 비슷하였다. 그리고 확산튜브를 부착한 두 가지의 MA 용기에서 보관된 시금치의 품질은 차이가 없이 통기성 대조구에 비하여 우수하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.309-312
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• 1997

The dynamic characteristics of a continuous MMA/MA free-radical solution copolymerization reactor were studied. A mathematical model was developed and kinetic parameters which had been estimated in the previous work were used. With this model, bifurcation diagrams were constructed with various parameters as the bifurcation parameter to predict the region of stable operating conditions and to enhance the controller performance. It was shown that the steady-state multiplicity existed over wide ranges of residence time and jacket inlet temperature. Periodic solution branches were found to emanated from Hopf bifurcation points. Under certain conditions isola was also observed, which would result in poor performance of feedback controllers.

• 한국환경보건학회지
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• 제16권2호
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• pp.75-82
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• 1990

Carbaryl was degradaded to monomethylamine(MA) by bacterium. which isolated from lake sediment. Its carbaryl degradation was maximized when grown on mineral salt medium conditioning 20 $\mu$M of carbaryl as a sole carbon source at 26${\circ}$C and initial pH 7.0-9.0 Its degradation ability was minimized at initial pH 3.0 and 5.0 The percent conversions { (moles of MA in excess of control / mole of carbaryl added) $\times$ 100} for 10. 20. 40 and 80 $\mu$M of carbaryl were 18.6. 16.1. 18.1 and 11.6 respectively. It suggests that increasing amount of carbaryl added above 80 $\mu$M. the percent conversion should be decreased. The MA production by the bacterium was lineary related to the cultural time. After 7days culture. its percent conversion was 46.2. and this result suggests that a half amount of carbaryl would be hydrolyzed to MA by the bacterium within 8 days.