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A Study on the Molecular Weight Distribution of Starch (전분의 분자량 분포도에 관한 연구)

  • Kim Kyeong-Yee
    • Food Science and Preservation
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    • v.11 no.4
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    • pp.496-502
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    • 2004
  • Purified acorn starch was obtained from alkali precipitation method. Acorn amylose and acorn amylopectin were fractionated from purified acorn starch by butanol improvement method. Gel permeation chromatography (GPC) was used to measure molecular weight distribution of acorn starch, acorn amylose, acorn amylopectin and corn starch, corn amylose, corn amylopectin. GPC measurement diagrams were obtained by each retention time. And then, we used DMSO and DMF as solvent, pullulan as standard material. We calculated the Number-average molar mass (Mn), Weight-average molar mass (Mw) and polydispersity from molecular weight distribution of each sample. As a result of estimating molecular weight using GPC, Mw of amylose has small value than Mw of amylopectin. From this fact, the molecular structural aspects of amylose and amylopectin were predicted and it was in good agrement with the tendency of polydispersity by GPC. The polydispersity of starch had big value than amylose and amylopectin, from this result, it might be known that the range of molecular weight appeared broad by heterogeneous properties of two components. The viscosity of purified acorn starch, amylose, amylopectin seperated from acorn starch, was decreased by increasing the shear rate and raising the temperature exponentially. Acorn starch solutions exhibited pseudoplastic power law fluid behavior.

Prevalence of Nosema and Virus in Honey Bee (Apis mellifera L.) Colonies on Flowering Period of Acacia in Korea

  • Hong, In-Pyo;Woo, Soon-Ok;Choi, Yong-Soo;Han, Sang-Mi;Kim, Nam-Suk;Kim, Hye-Kyung;Han, Sang-Hoon;Lee, Man-Young;Lee, Myeong-Lyeol;Byeon, Kyu-Ho
    • Mycobiology
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    • v.39 no.4
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    • pp.317-320
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    • 2011
  • Honey production from approximately 1.6 million colonies owned by about 199,000 Korean beekeepers was almost 23,000 metric tons in 2009. Nosema causes significant losses in honey production and the virus decreases population size. We initiated a survey of honey bee colonies on the blooming period of Acacia to determine the prevalence of Nosema and virus in 2011. Most Korean beekeepers have moved from the south to north of Korea to get Acacia nectar for 2 mon. This provided a valuable opportunity to sample bees originating from diverse areas in one location. Twenty hives owned by 18 beekeepers were sampled in this year. Nosema spore counts ranged from zero to 1,710,000 spores per bee. The average number of nosema spores per bee was 580,000. Approximately 95% of the colonies were infected with Nosema, based on the presence of spores in the flowering period of Acacia. This indicates that Nosema is the predominant species affecting honeybee colonies. Also, the seven most important honeybee viruses were investigated by reverse transcription-PCR. Among them, four different viruses were detected in samples. Black queen cell virus was present in all samples. Chronic bee paralysis virus was detected in 10% of samples. Deformed wing virus was present in only 5% of the samples. Prevalence of Sacbrood virus was 15%. However, Cloudy wing virus, Israel acute paralysis virus and kashmir bee virus were not detected in any of samples.

Effect of Chemical Composition of Nut Material on the Fracture Behavior in Nut Projection Welding of Hot-Stamped Steel Sheet (핫스탬핑강의 너트 프로젝션 용접시 너트 재질이 용접부 파단모드 변화에 미치는 영향)

  • Lim, Sung-Sang;Kim, Young-Tae;Chun, Eun-Joon;Nam, Ki-Sung;Park, Young-Wan;Kim, Jae-Wan;Lee, Sun-Young;Choi, Il-dong;Park, Yeong-Do
    • Journal of Welding and Joining
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    • v.34 no.2
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    • pp.1-10
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    • 2016
  • The use of materials for modern lightweight auto-bodies is becoming more complex than hitherto assemblies. The high strength materials nowadays frequently used for more specific fields such as the front and rear sub frames, seat belts and seats are mounted to the assembled body structure using bolt joints. It is desirable to use nuts attached to the assembled sheets by projection welding to decrease the number of loose parts which improves the quality. In this study, nut projection welding was carried out between a nut of both boron steel and carbon steel and ultra-high strength hot-stamped steel sheets. Then, the joints were characterized by optical and scanning electron microscope. The mechanical properties of the joints were evaluated by microhardness measurements and pullout tests. An indigenously designed sample fixture set-up was used for the pull-out tests to induce a tensile load in the weld. The fractography analysis revealed the dominant interfacial fracture between boron steel nut weld which is related to the shrinkage cavity and small size fusion zone. A non-interfacial fracture was observed in carbon steel nut weld, the lower hardness of HAZ caused the initiation of failure and allowed the pull-out failure which have higher in tensile strengths and superior weldability. Hence, the fracture load and failure mode characteristics can be considered as an indication of the weldability of materials in nut projection welding.

An Overview for Molecular Markers in Plants (식물에서 분자 마커의 동향)

  • Huh, Man Kyu
    • Journal of Life Science
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    • v.25 no.7
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    • pp.839-848
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    • 2015
  • A molecular marker is a molecule contained within a sample taken from an organism or other matter. The development of molecular techniques for genetic analysis has led to a great contribution to our knowledge of plant genetics and our understanding of the structure and behavior of various genomes in plants. Recently, functional molecular markers have been developed to detect the presence of major genes from the analysis of pedigreed data in absence of molecular information. DNA markers have developed into many systems based on different polymorphism-detecting techniques or methods such as RFLP, AFLP, RAPD, SSR, SNP, etc. A new class of very useful DNA markers called genic molecular markers utilizing the ever-increasing archives of gene sequence information being accumulated under the EST sequencing projects on a large number of plant species. Functional markers are derived from polymorphic sequences, and are more likely to be involved in phenotypic trait variation. Based on this conceptual framework, the marker systems discussed below are all (gene)-targeted markers, which have the potential to become functional. These markers being part of the cDNA/EST-sequences, are expected to represent the functional component of the genome i.e., gene(s), in contrast to all other random DNA based markers that are developed/generated from the anonymous genomic DNA sequences/domains irrespective of their genic content/information. Especially I sited Poczai et al’ reviews, advances in plant gene-targeted and functional markers. Their reviews may be some useful information to study molecular markers in plants.

Antiproliferative and Antioxidative Activities of Methanol Extracts of Echinacea angustifolia (Echinacea angustifolia 메탄올 추출물의 암세포 증식억제 및 항산화 효과)

  • Lee Joon-Kyoung;Koo Seung-Ja
    • Korean journal of food and cookery science
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    • v.21 no.3 s.87
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    • pp.311-318
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    • 2005
  • Echinacea, also blown as the purple coneflower, is a herbal medicine that has been used for centuries, customarily as a treatment for the common cold, coughs, bronchitis, upper respiratory infections, and some inflammatory conditions. We investigated the effects of methanol extracts of Echinacea angustifolia on the cytotoxicity against cancer cells $(HepG_2,\;3LL,\;HL60,\;L1210)$ and antioxidative activity. From the test results, each part of Echinaceashowed a cytotoxic effect against the cancer cell lines, and this cytotoxic effect increased with increasing sample concentration. At 1.0 mg/mL concentration the relative cytotoxic activities of the flower bud, leaf, stern and root parts were $90.5\%,\;52.7\%,\;37.1\%\;and\;19.2\%$, respectively, in $HepG_2$ cells, and $75.5\%,\;93.3\%,\;81.2\%,\;and\;75.1\%$ respectively, in HL60 cells, as evaluated by MTT assay. $IC_{50}(50\%\;inhibitory\;concentration)$ of the methanol extracts of the Echinacea flower bud was 0.214 mg/mL on /$HepG_2$ cells, and that of the Echinacea leaf and root was 0.166 mg/mL and 0.210 mg/mL, respectively, on HL60 cells. After /$HepG_2$ cells were incubated for 6 days at $37^{\circ}C$ with various concentrations of each part, the cell number increased while the inhibition rate on the /$HepG_2$ cell growth decreased. The antioxidative activities of the flower bud, leaf, stem and root parts were $59.0\%$ (0.75 mg/mL), $80.76\%$ (0.5 mg/mL), $95.5\%$ (0.25mg/mL) and $98.15\%$ (0.25 mg/mL), respectively, as evaluated by electron donating ability. These results indicated that Echinacea angustifolia has strong anticancer and antioxidative effects in vitro.

Effect of Addition of Ethanol on the Quality of Kimchi Paste (에탄올 첨가가 김치 양념의 품질에 미치는 영향)

  • Kang, Miran;Jung, Hyemin;Seo, Hye-Young
    • Korean journal of food and cookery science
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    • v.31 no.6
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    • pp.725-732
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    • 2015
  • This study was conducted to evaluate the effects of ethanol on the prolongation of the shelf-life of kimchi paste. Kimchi paste was prepared by adding 0.5~3.0% ethanol, and then stored at $4^{\circ}C$ for 35 days. The retardation of kimchi paste fermentation was evaluated by measuring chemical, microbial, and sensory characteristics. Titratable acidity and pH showed a slight difference, depending on the ethanol concentration. The titratable acidity showed the low content in kimchi paste with 3.0% ethanol during fermentation, whereas the pH showed a reverse tendency, indicating that fermentation was inhibited under a high ethanol concentration. The changes in the sugar-reduced contents were similar to that of the pH. The growth of microorganisms such as total aerobic bacteria, lactic acid bacteria, yeasts and molds in kimchi paste during fermentation were inhibited by ethanol, and the addition of 3.0% ethanol was most effective to inhibit the microbial growth. The number of coliform bacteria was decreased during fermentation of kimchi paste and not detected in any sample at 35 days, except for kimchi paste with 3.0% ethanol. In sensory evaluation, the addition of 0.5~1.5% ethanol in kimchi paste was showed no significant difference on sensory properties compared to the kimchi paste without ethanol (p<0.05). As a result, it is considered that the addition of 1.5% ethanol is the most appropriate to maintain the quality of kimchi paste, without the changing the flavor.

Effect of Small and Medium Businesses' R&D Intensity and Patents on Their P/E Ratios (중소기업의 연구개발집중도와 특허가 주가수익률에 미치는 영향 연구)

  • Park, Jung-Hee;Yeo, In-Gook;Moon, Jong-Beom
    • Journal of Korea Technology Innovation Society
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    • v.14 no.3
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    • pp.466-487
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    • 2011
  • This study analyzed the effect of small and medium businesses' R&D intensity and patents on their price-earnings (P/E) ratios. Regression analysis was conducted on a sample of manufacturers listed on the Korean Securities Dealers Automated Quotations (KOSDAQ) for the past decade (2000~2009). The result is summarized as follows. First, a negative correlation was identified between companies' R&D intensity and their P/E ratios, but no significant relationship was found between their numbers of domestic patent applications and registrations and P/E ratios. Second, the analysis of the effect of the companies' R&D intensity on their P/E ratios resulted in a negative correlation of -1%. Third, the analysis of the effect of the companies' number of domestic patent applications and registrations on their P/E ratios showed that they did not have any significant relationship. Fourth, high-tech firms' R&D intensity had a negative correlation of -1% with their P/E ratios, but had a positive correlation of 1% with their numbers of domestic patent applications. Furthermore, the R&D intensity of middle-to-high and middle-to-low tech enterprises had a negative correlation of -1% with their P/E ratios, whereas their numbers of domestic patent applications and registrations had no significant relationship with their P/E ratios. The above results suggest that to produce successful outcomes from their R&D investment and patents, individual firms need strategies for technological innovation that relate to their technological level.

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Youth Startup Firms: A Case Study on the Survival Strategy for Creating Business Performance (청년창업기업의 창업초기 생존전략 : 중진공 청년전용자금 활용기업 사례)

  • Lee, Seung-Chang;Lim, Won-Ho;Suh, Eung-Kyo
    • Journal of Distribution Science
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    • v.12 no.6
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    • pp.81-88
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    • 2014
  • Purpose - Entrepreneurship promotion is emerging as an important economic growth agenda. However, in Korea, entrepreneurship has weakened because of the collapse of the venture bubbles of the 2000s and the global economic recession in 2008, which have induced the business community to choose stability over risk. The Korean government has been implementing several support projects to inspire and promote youth entrepreneurship through various means including financial assistance; however, the perpetuation rate of young entrepreneurship is still low as compared to advanced economies such as the US and EU. This case study focuses on the Youth Start-Up Business Support Program of the Small & Medium Business Corporation, and explores practical alternatives. Further, it aims to suggest managerial factors and a conceptual model for change management factors affecting the business performance creation of a startup company, based on the Small and medium Business Corporation's young venture startup fund. Research design, data, and methodology - Many studies examine the current progress and issues of startup firms, for example, a lack of systematic cultivation of entrepreneurship and startup business training, lack of commercialization funding for youth startup businesses, lack of mentoring, and inadequate infrastructure. From prior research, we address four factors, namely, personal managerial capabilities, innovative business model, sufficient cash flow, and social network, affecting startup companies' business performance. This study involved a sample survey of 200 young entrepreneurs to investigate casual relations between the four factors and business performance. A regression analysis was used to verify the hypotheses. Results - First, in relation to differences in the founder's personal characteristics, age, sales amount, and number of employees significantly impact business performance. Second, regarding the causal relation between the four factors for creating business performance, an innovative business model and social networking have supported the hypotheses, revealing that the more that a start-up founder has an innovative business model and social networking, the more the start-up firms are likely to have better performance (e.g., sales volume, employment, ROE, ROI, etc.). Although the founder's competency and sufficient cash flow have no significant relationship with business performance, the mean value was higher performance for high founder's competency and sufficient cash flow. Conclusions - This study provides basic data on policy support strategies of the Small and Medium Business Corporation, to help young entrepreneurs achieve their start-up business goals. It shows that young entrepreneurship startup firms should strive to explore ideas to satisfy customers' needs, and that changes in customer value and the continuous innovation of business model differentiation are required to actively respond to change management. Moreover, at the infant startup stage, they should activate social network programs to share information, thereby offsetting resource scarcity and managing business risk. Further, the establishment of a long-term vision and the implementation of training programs in related specific fields should be supported to strengthen founders' personal capabilities.

ACCURACY OF TRI AUTO ZX® IN LOCATING APICAL FORAMEN WITH ROTARY FILE (전동 file을 장착한 Tri Auto ZX®의 치근단공 인지 정확도 평가)

  • Park, Jeong-Won
    • Restorative Dentistry and Endodontics
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    • v.24 no.4
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    • pp.578-584
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    • 1999
  • The purpose of this experiment was to determine: (1) the safe automatic apical reverse setting that prevents overinstrumentation of the root canal, using Tri Auto ZX$^{(R)}$ and (2) the effect of various irrigant on such instrumentation. The instrumentation was carried out with the automatic apical reverse setting of 0.5, 1.0, 1.5, and 2.0. The root canal irrigants used in usual manner were normal saline(0.9%), NaOCl(2.5%), and RC Prep$^{(R)}$. For each reverse setting and each irrigant, ten teeth were used with the total of 120 teeth. The distance between the file tip and the apical constriction was determined by stereomicroscope using the point that the file began to rotate in reverse direction. When the reverse setting mode was set to 0.5, 18 of 30 were overinstrumented. If these were discriminated by irrigant, 10 of 6 with 0.9% saline, 10 of 6 with NaOCl, and 10 of 6 with RC Prep$^{(R)}$ has the file tip located 0.57${\pm}$0.30mm, 0.73${\pm}$0.39mm, and 0.26${\pm}$0.25mm beyond the apical constriction respectively. In 1.0 setting 15 of 29 were over the apical constriction, and the distribution was 6 in saline, 5 in NaOCl, and 4 in RC Prep$^{(R)}$. The mean distance over the apical constriction was 0.28${\pm}$0.13mm with saline, 0.75${\pm}$0.61mm with NaOCl, and 0.25${\pm}$0.17mm with RC Prep$^{(R)}$. When the autoatic reverse mode was set to 1.5, and 2.0, 5, and 1 teeth were found to be overinstrumented in respective settings. But there were large variations in overinstrumented distances when an attempt was made to compare the effect of irrigants on this overinstrumentations and they were meaningless for the small sample size. When all of the autoreverse setting were combined to compare the number of overinstrumented teeth with each irrigant, there were no significant differences (14 for normal saline, 12 for NaOCl, 13 for RC Prep$^{(R)}$). When 0.5 or 1.0 automatic apical reverse setting mode was used the Tri Auto ZX$^{(R)}$ in clinical application, the possibility of overinstrumentation beyond the apical constriction exists in 55.9% of cases. Therefore 1.5 or 2.0 setting is safer for the preparation inside the canal but this type setting needs additional apical hand preparation of the root canal because the accuracy is lower than 0.5 or 1.0 setting.

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A Study on the Effects of Health Education and Self-Care Status on the Aged Diabetics (노인요당 양성자의 질병관리에 대한 교육 및 추후 관리 양상에 관한 연구)

  • Rhee Seon Ja;Kwon Yeon Hee
    • Journal of Korean Public Health Nursing
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    • v.2 no.2
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    • pp.99-116
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    • 1988
  • This study examined the effect of Health Education on the aged. One of the Study objectives was to improve knowledge. attitude and self-care practice about diabetes of the aged who have responded positive in the urine sugar test. The other study objective was to find out factors influencing knowledge. attitude and self-care practice about diabetes. and the relationship among the three variables. The subjects, consisting of 45 positive responders in the urine sugar test, were selected from the elderly who attend elderly citizen center in southern part of Seoul Then they were divided into an experimental and a control group. The study design was set to compare the pre and post test data between the experimental and the control group with the measures of results from Health Education services including nursing care intervention programs on the aged diabetics. The first data collection was carried out in August. 1986 through questionaires and urine sugar testing. The second data collection was done in September, 1987 through the same methods. The results of the study are summarized as follows; 1. General characteristics of the subjects The experimental group has 9 females and 14 males and the control group has 12 females and 10 males. As for the educational level, more than half of the subjects in both group had completed at least 6 years of education. And there was no significant difference in urine sugar levels between the two groups. 2. The effect of Health Education on the extent of change in knowledge, attitude and self-care practice about diabetes was found to be significant. The first hypothesis that knowledge, attitude and self-care practice about diabetes in the aged will be unchanged by Health Education. was rejected by increased the three variables and decreased urine suger level in the experimental group. The second hypothesis that knowledge, attitude and self-care practice about diabetes wouldn't be concerned with each other, was rejected. That is. the three variables and urine sugar levels showed a significant positive relationship with each other but diabetic knowledge to urine sugar level had an insignificant positive relationship. The third hypothesis that the amount of learning Health Education will have no relationships with knowledge. attitude and self-care practice about diabetes. was rejected. That is, the more number of times an elderly person participated in Health Education. they increased their diabetic knowledge. attitude and self-care practice and decreased their urine sugar level. 3. Except for Health Education, an other factor influencing diabetic knowledge was educational level. And an other factor influencing the diabetic attitude was experience of the diagnosis of diabetes. 4. Except for Health Education. the other factors influencing self-care practice were experience of the diagnasis of diabetes, sex and experience of the hospitalization for diabetes. But factors influencing urine sugar level weren't found. Although the results seem to be plausible, this study is not without its problems. In paticular, the sample used is limited in its scope and size. So, more empirical work needs to be done for other diseases as well as diabetes before any general conclusions are to be made.

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