• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.1015-1025
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• 2015

The development of diverse polymyxin derivatives is needed to solve the toxicity and resistance problems of polymyxins. However, no platform has generated polymyxin derivatives by genetically engineering a polymyxin synthetase, which is a nonribosomal peptide synthetase. In this study, we present a two-step approach for the construction of engineered polymyxin synthetases by substituting the adenylation (A) domains of polymyxin A synthetase, which is encoded by the pmxABCDE gene cluster of Paenibacillus polymyxa E681. First, the seventh L-threonine-specific A-domain region in pmxA was substituted with the L-leucine-specific A-domain region obtained from P. polymyxa ATCC21830 to make polymyxin E synthetase, and then the sixth D-leucine-specific A-domain region (A_6-D-Leu-domain) was substituted with the D-phenylalanine-specific A-domain region (A_6-D-Phe-domain) obtained from P. polymyxa F4 to make polymyxin B synthetase. This step was performed in Escherichia coli on a pmxA-containing fosmid, using the lambda Red recombination system and the sacB gene as a counter-selectable marker. Next, the modified pmxA gene was fused to pmxBCDE on the chromosome of Bacillus subtilis BSK4dA, and the resulting recombinant strains BSK4-PB and BSK4-PE were confirmed to produce polymyxins B and E, respectively. We also succeeded in constructing the B. subtilis BSK4-PP strain, which produces polymyxin P, by singly substituting the A_6-D-Leu-domain with the A_6-D-Phe-domain. This is the first report in which polymyxin derivatives were generated by genetically engineering polymyxin synthetases. The two recombinant B. subtilis strains will be useful for improving the commercial production of polymyxins B and E, and they will facilitate the generation of novel polymyxin derivatives.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.8 no.3
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• pp.293-301
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• 2001

Purpose: The purpose of this study was to investigate the effect of exercise therapy and relaxation therapy on the level of ACTH and cortisol in workers and to determine, from this information, the effectiveness of applied exercise therapy and relaxation therapy as a nursing intervention method for workers experiencing stress. Method: The subjects were divided into an exercise therapy group. a relaxation therapy group, and a control group. The research design was a nonequivalent control group pretest-posttest design (exercise therapy : n=12. relaxation therapy: n=12, control group, the group without exercise or relaxation therapy: n= 12). The subjects in the exercise therapy group were given a particular intensity for each kp over 30 min, bicycle ergometer which uses the LX PE training system before and after four weeks of training. The subjects did 60-70% exercise intensity exercise therapy for eight weeks The relaxation therapy subjects were trained using a modified Jacobson's relaxation technique for eight weeks. The exercise and relaxation therapy groups were trained at the following intensity for eight weeks (3 times/week, 30 min/day). Changes in the levels of ACTH and cortisol were identified. Two-way ANOVA and multiple range test (SNK: Student Newman Keul) were used to examine the effects of exercise therapy and relaxation therapy at four and eight weeks. Result: 1. Changes in the level of ACTH in the relaxation therapy group were statistically significant at .05 level, and were better than that of the exercise therapy group after eight weeks. But there was no significant difference between the exercise therapy group and the control group. 2. Change in the level of cortisol in the relaxation therapy group were statistically significant at .05 level as compared to the exercise therapy group and the control group after four weeks, but not after eight weeks. Also, the relaxation therapy was statistically significant at .05 level after four weeks compared to before treatment, but there was a tendency toward increased cortisol after eight weeks. Conclusion: Relaxation therapy was found to be more effective in stress treatment than exercise therapy and as such is a desirable nursing intervention method for stress hormone reduction in workers.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.270-276
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• 1993

Leaf lettuce (Lactuca sativa L., var. crispa) packed in $20{\mu}m$ LDPE (perforated), $20{\mu}m$ LDPE, $30{\mu}m$ HDPE, and $40{\mu}m$ LDPE pouches was stored at $4^{\circ}C,\;10^{\circ}C\;and\;20^{\circ}C$. The quality of leaf lettuce during the storage was investigated in terms of weight loss, color, soluble solids content, texture and sensory properties. Leaf lettuce exhibited the highest storage stability at $4^{\circ}C$. Shelf-life of the packed leaf lettuce was prolonged approximately $10{\sim}15$ times in comparision with that of the unpacked under all temperature conditions. Among the packed leaf lettuce, self-life in $20{\mu}m$ LDPE (perforated) and $20{\mu}m$ LDPE pouches was relatively short mainly due to discoloration and deterioration. On the other hand, the quality of the leaf lettuce packed in $30{\mu}m$ HDPE and $40{\mu}m$ LDPE pouches was kept well during the storage. Particularly, $40{\mu}m$ LDPE pouches conferred the shelf-life superior to other film pouches.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.83-93
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• 2012

This paper proposes an image segmentation framework that modifies the objective function of Fuzzy C-Means (FCM) to improve the performance and computational efficiency of the conventional FCM-based image segmentation. The proposed image segmentation framework includes a locally weighted fuzzy c-means (LWFCM) algorithm that takes into account the influence of neighboring pixels on the center pixel by assigning weights to the neighbors. Distance between a center pixel and a neighboring pixels are calculated within a window and these are basis for determining weights to indicate the importance of the memberships as well as to improve the clustering performance. We analyzed the segmentation performance of the proposed method by utilizing four eminent cluster validity functions such as partition coefficient ($V_{pc}$), partition entropy ($V_{pe}$), Xie-Bdni function ($V_{xb}$) and Fukuyama-Sugeno function ($V_{fs}$). Experimental results show that the proposed LWFCM outperforms other FCM algorithms (FCM, modified FCM, and spatial FCM, FCM with locally weighted information, fast generation FCM) in the cluster validity functions as well as both compactness and separation.

• Journal of Korea Soil Environment Society
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• v.5 no.1
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• pp.3-12
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• 2000

The multi-region model, to describe preferential flow, is an equation representing solute transport in soils by dividing soil into numerous pore groups and using the hydraulic properties of the soil. As the model partial differential equation (PDE) is solved numerically with finite difference methods. a modified equivalent partial differential equation(MEPDE) of the partial differential equation of the multi-region model is derived to analyze the accuracy and consistency of the solution of the model PDE and the Von Neumann method is used to analyze the stability of the finite difference scheme. The evaluation obtained from the MEPDE indicated that the finite difference scheme was found to be consistent with the model PDE and had the second order accuracy The stability analysis is performed to analyze the model PDE with the amplification ratio and the phase lag using the Von Neumann method. The amplification ratio of the finite difference scheme gave non-dissipative results with various Peclet numbers and yielded the most high values as the Peclet number was one. The phase lag showed that the frequency component of the finite difference scheme lagged the true solution. From the result of the stability analysis for the model PDE, it is analyzed that the model domain should be discretized in the range of Pe < 1.0 and Cr < 2.0 to obtain the more accurate solution.

• Food Science and Preservation
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• v.16 no.2
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• pp.139-146
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• 2009

Whole and stem-off cherry tomatoes were packaged using perforated films(LF05, LF10, LF20, and LF40). Gas composition(ethylene, $O_2$, and $CO_2$), firmness(compression and penetration force), color, brix degree, acidity, and total microbial counts were assessed during storage at $10^{\circ}C$ and 85% relative humidity. Gas composition varied with film gas permeability, indicating that modified atmospheric(MA) conditions were achieved. Firmness fell during storage; samples packed using LF05 showed the lowest firmness, corresponding to low gas transmission conditions. L(lightness) and a(redness) values respectively decreased and rose slightly with increasing storage time, but the b(yellowness) values fell notably. Film permeability significantly affected acidity and soluble solid levels. When LF40 packaging was used, acidity and brix scale changes were similar to those seen after PET container packaging. Total microbial counts increased with time after packaging in most films, and pretreatment differences were not significant. Microflora varied between stem on/off tomatoes. Skin wrinkling and juice appearance were common in tomatoes stored in PET containers and LF films of low gas permeabilities(LF05, LF10, and LF20). White molds were partially found on stem-on tomatoes stored using packaging systems. When film packagings were compared, LF40 was optimal, permitting minimal pretreatment yet offering maximal sanitation.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.119-128
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• 2023

This study was examined for investigating the quality changes of spring kimchi cabbage under various treatments (pre-drying/pre-cooling, packaging types, and stacking and loading in container and pallete in the storage room) during cold storage. The results showed that control (upward stacking without pre-drying/pre-cooling and HDPE or PVC film cover) was increased significantly in weight loss and trimming loss, compared to other treatments such as DPDH (downard stacking + pre-drying + HDPE), DPDP (downard stacking + pre-drying + PVC), DPCH (downnard stacking + pre-cooling + HDPE), and UPCH (upward stacking + pre-cooling +HDPE) during storage for three months. In Sensory evaluation, judging from marketable properties, the desirable appearance of spring kimchi cabbage with the modified pallet-unit MA packed, PE, and PVC film wrapping could be maintained until 9 weeks after pre-drying/pre-cooling. Meanwhile, the control without any treatments after 6 weeks, the sensory score was declined, significantly. In general, the low temperature (10℃ and 2℃) of pre-treatment with combination of plastic film packaging in spring kimchi cabbage storage could inhibit the physiological activity and reduce the direct exposure of environmental cold air in the storage. Therefore, these two variables were the key points for extending the shelf-life of spring kimchi cabbage.

• Food Science and Preservation
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• v.24 no.6
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• pp.734-745
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• 2017

The effects of combination treatment with sulfur dioxide generating pad ($SO_2$ pad) and modified atmosphere packaging (MAP) on grape quality were examined under simulated exporting condition and actual export to Los Angeles, USA. The 'Campbell Early' grape harvested in Hwaseong, Gyeonggi was precooled at $0^{\circ}C$, selected and packaged at $10^{\circ}C$, and stored at $0^{\circ}C$ for 30 days. The treatment was as follows: general export packaging (control), only $SO_2$ pad, combination of $SO_2$ pad and MAP (perforated polyethylene film, $SO_2$ pad+MA). In case of control and only $SO_2$ pad under simulated exporting condition, the grape quality changes with storage time were decrease in hardness and brush length, increase in stem browning, and increased in shattering rate. The treatment of $SO_2$ pad+MA was the most effective in preserving the grape quality since $SO_2$ concentration inside the package remained around 2.9 ppm by MA film. Grape exports from harvest to local distribution of the USA took 30 days, and only $SO_2$ pad+MA package showed no fungus, maintained brush length and rachis color, and was lowest at 4.0% of shattering rate since the concentration of $SO_2$ in the package was about 4.0 ppm. As a result, it was considered that the combination of $SO_2$ pad and MA was the most effective way to maintain freshness of grape during long-term marine transportation and extend the shelf-life in exporting countries.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.6 no.2
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• pp.240-254
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• 1999

The purpose of this study was to investigate the effect of exercise therapy and relaxation therapy on catecholamine and heart rate in people in white color jobs and to determine this information the effectiveness of applied exercise therapy and relaxation therapy as a nursing intervention method for stress patients. The subjects were divided into an exercise therapy group, a relaxation therapy group, and control group and the research design was a nonequivalent control group pretest-post test design(exercise therapy : n= 12, relaxation therapy : n=12, control group, the group without any treatment in exercise on relaxation therapy : n=12), The subjects in the exercise therapy group were given a particular intensity for each kp during 30min, bicycle ergometer which is using an LX PE training system before & after 4weeks of training. The exercise therapy that was used was Astrard load method which tested absolute exercise load of heart rate before & after four weeks, and resting heart rate was tested for exercise and relaxation therapy before, after four weeks, and at eight weeks. The results of each kp & absolute exercise load were calculated with the target rate formula(maximal heart rate-rest heart rate) x exercise intensity(%) + rest heart rate so the subjects could continue 60-70% exercise intensity for exercise therapy over eight weeks. The relaxation therapy subjects were trained using a modified Jacobson's relaxation technique for eight weeks. The exercise and relaxation therapy were trained at the following intensity for eight weeks(3times/week, 30min/day) to see changes in catecholamine & heart rates. After eight weeks, statistical analysis of exercise & relaxation therapy were carried out Two-way ANOVA and multiple range test(SNK : Student Newman Keul) were used. The results are as follows : 1. The change of epinephrine & norepinephrine in the exercise therapy, relaxation therapy, and control group was statistically significant at the .05 level after four weeks & eight weeks. Also, exercise therapy was statistically significant at .05 level over that of the control group after 4weeks. 2. The change of heart rate in relaxation therapy was statistically significant at the .05 level, and was statistically significant at the .05 level over that of the exercise therapy and control group. In conclusion, it is obvious that exercise therapy and relaxation therapy should be one of the most effective stress treatment and desirable nursing interventions methods for job stress in people in white color jobs.

• Korean Journal of Human Ecology
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• v.5 no.2
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• pp.55-74
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• 2002

This study, observing each respectively packaged Kongdduk during 12-day storing period and comparing it with unpackaged Kongdduk, through a cross-sectional view of its fiber and temperament, through a sensory evaluation rheometer measurement of rheological change depending on storing period and packaging type and through the organic acid content, micro-organic change, and retrogressive process. The results are as follows: 1. Kongdduk made of bean oil shows better chewiness, cohesiveness, and moistness than Kongdduk made of bean flour while Kongdduk made of bean flour shows better rheological properties as to roasted nutty taste or roasted nutty order. 2. The test of the cutted loaves of Kongdduk shows that adding oil of proper proportion to the dough of steamed rice cake in accordance with the amount of rice flour has a good influence on rheological properties of softness. 3. Rice cakes were prepared by addition of yellow soybean flour or peanut flour and packaged with CMP or VP, and their physical characteristics were monitored by sensory evaluation and mechanical measurement while storing for 6 days. For VP samples, yellow soybean rice cake showed little changes in cohesiveness, moistness and chewiness for 6 days of storage, while pure rice cake and peanut rice cake showed an increase in strength and hardness from the 4th day of storage. In case of CMP, yellow soybean rice cake hardly showed a difference in cohesiveness, moistness and chewiness for 6 days, while pure rice cake and peanut rice cake showed a significant difference from the 4th day in sensory evaluation. 4. For rheometer measurement, yellow soybean rice cake with CMP or VP showed little changes in strength or hardness for 6 days, while peanut rice cake and pure rice cake showed a drastic decrease in cohesiveness, from the End day and adhesiveness from the 4th day of storage. As there was no remarkable difference or deterioration for 6 days of storage in yellow soybean rice cake between CMP and VP, the ingredients of rice cakeappeared to be more important than the type of packaging in terms of quality deterioration of rice cake. 5. As the storing period passed by, organic acid is detected less at CMP-packaged Knngdduk than at wrapped. and its increasing speed proves to be slower as well. 6. The one wrapped with plyethylene film began to get moldy from pure rice cake or Kongdduk (rice cake mixed with yellow soybean or peanut) after 6 days, and more and more modly after 9 daysor after 12 days, but the CMP-packaged ones didn't get modly until 12 days or more. 7. CMP-packaged Kongdduk showed higher enthalpy of retrogradation than PE-wrapped one. As storing Period Passed by, Kongdduk,s enthalpy grew high. That is to say, it shows that Kongdduk got retrograded.