• Journal of Life Science
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• v.31 no.10
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• pp.960-968
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• 2021

Since microalgae research started on late 18 century, they have been recognized as one of the most important bioresources used in bioindustry. Owing to the large efforts paid to industrial application of this microorganisms, their importance on food/feed and bioactive compounds has been further extending into the environmental research areas including alternative energy resources, mitigation of the carbon emission, and waste-water treatment. However, despite the importance on their industrial application, the fundamental research field related to the long-term preservation of microalgae culture has not received much attention. However, a less labor intensive and cost-efficient preservation technology enabling biologically active and stable microalgae-culture provides a key success factor in the biotechnological application. Therefore, this study investigated various cutting-edge microalgae cryopreservation technologies currently developed so far, mainly targeting Chlorophyta, which occupies the largest taxon in the classification system of microalgae. In addition, for the development of successful cryopreservation technique, the key factors such as temperature control effect and preservative effect during cryopreservation of microalgae culture were investigated. In addition, the problems with current preservation technology that is being used in Korean domestic biological resource banks and the international microalgal resource banks are described. According to our investigation, currently no standard method for long-term preservation of microalgae is available due to their various morphological and physiological characteristics. To overcome such issues, much more efforts on fundamental research area on the identification of specific biomarker used for microalgae taxonomical classification and further systemic approaches based on strain-specific cryopreservation methods needed.

• Journal of Nutrition and Health
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• v.54 no.5
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• pp.425-434
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• 2021

The discovery of the relationship between nutrients and deficiency diseases during the 100 years from the mid-1800s to the mid-1900s was a breakthrough that led to advances in the study of nutrition. The Recommended Dietary Allowances (RDA) were created as a quantitative standard for avoiding diseases caused by nutrient deficiency. In addition, a reductionism paradigm has become generally accepted among nutrition scholars in health and disease, which focused on the properties of individual nutrients, content in foods, cellular levels, and mechanisms of action. The reductionist paradigm worked very well for the prevention and treatment of malnutrition diseases. However, as the incidence of nutrient deficiencies decreased and that of chronic diseases increased, the nutrition goals have been changed to secure safe and adequate nutrient intake and to reduce chronic disease risks. Accordingly, Dietary Reference Intakes (DRIs), a set of nutrient-based reference values, were designed to replace the RDA. The revised Korean DRIs were published for 40 nutrients in 2020. However, there is still room for improvement in the reference intake levels targeted at reducing the risk of chronic disease. The reductionist approach can no longer be practical because chronic diseases are related to the interactions between multi-components in the foods and multi-targets in the body. Therefore, a second innovative leap is needed following the nutrition development breakthrough made over 100 years ago. To this end, the nutrition paradigm must evolve from reductionism to a holism approach. Cutting-edge scientific technologies, such as metabolomics, transcriptomics, microbiomics, and bioinformatics, should also be acceptable in nutrition science based on the knowledge gained from basic nutrition studies.

• Korean Journal of Psychosomatic Medicine
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• v.30 no.2
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• pp.172-178
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• 2022

Objectives : Although subclinical depression symptoms are associated with suicidal idea, most research have focused on clinical depression such as major depressive disorder or dysthymia. The aim of this study is to investigate network structure of depressive symptom and to reveal which symptoms are associated with suicidal ideation. Methods : We used part of data from the seventh Korea National Health and Nutrition Examination Survey. Participants were between 19 and 65 years of age (N=8,741). Network analysis with Isingfit model is used to reveal network structure of depressive symptoms and most central symptom and edges assessed by patient health questionnaire (PHQ-9). Results : The most two central symptoms were psychomotor activity and suicidal ideation. The strongest edge was psychomotor activity-suicidal ideation. Suicidal ideation also has strong association with depressive mood and worthlessness. Conclusions : These results suggest that psychomotor activity and suicidal ideation can serve as treatment target for subclinical depression and psychomotor activity, worthlessness and depressed mood may be important factor for early intervention of suicidal ideation.

• Journal of Plant Biotechnology
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• v.50
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• pp.169-175
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• 2023

A plant regeneration system was developed through shoot organogenesis from in vitro leaf explants of Chrysanthemum morifolium 'Ohblang'. The effects of different concentrations of plant growth regulators and AgNO₃ on efficient shoot regeneration and inhibition of browning were evaluated in chrysanthemum. The explants were cultured on MS shoot induction medium supplemented with 12 combination treatments of 6-benzyladenine (BA) 0.5, 1.0 and 2.0 mg/L, and α-naphthaleneacetic acid (NAA) 0.2, 0.5, 1.0 and 2.0 mg/L in darkness for 6 weeks and cultured under a 16/8 h photoperiod for 6 weeks. The highest shoot regeneration was obtained from the explants cultured on the medium with 1.0 mg/L BA and 1.0 mg/L NAA. Based on this result, AgNO₃ was added to a shoot induction medium containing MS salts, vitamins, 1.0 mg/L BA, 1.0 mg/L NAA, 30 g/L sucrose, and 6 g/L agar to reduce browning of chrysanthemum leaf explants. In the control treatment without AgNO₃, leaf explants turned brown at the cut edge; however, browning was not observed in AgNO₃ treatments. Shoot organogenesis was higher at low concentrations of AgNO₃ and decreased with an increase in AgNO₃ concentration. The explants cultured on shoot induction medium (MS salts, vitamins, 1.0 mg/L BA, 1.0 mg/L NAA) with 1 mg/L of AgNO₃ produced the highest shoot regeneration with 2.6 shoots per explants and a browning index of 0.7. When the regenerated shoots were detached from the explants and cultured on MS medium, the shoots were elongated and rooted successfully.

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.373-389
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• 1997

The purpose of this stdudy was to evaluate the effect of maxillary protraction and the relapse of hard and soft tissue after maxillary protraction. For this study 29 patients who were treated with maxillary protractor and labiolingual archwire were selected. Their mean age was 9 years 4 months and mean treatment period was 8.5 months. Lateral cephalograms were taken at pretreatment, immediately after treatment and one to three months after removal of the maxillary protractor. They were traced on skeletodental and soft tissue structures based on Burstone's analysis and analyzed by Quick-Ceph Image Digitizing System(ORTHODONTIC PROCESSING). The mean and standard deviation between pretreatment and posttreatment and between posttreatment and retention period for each cephalometric variable were calculated. Student t-test was used to determine the statistical significance of the changes in each variable. Correlation coefficients between hard tissue and soft tissue were used to determine interrelationship. The results were as follows. 1. After maxillayy protraction, the maxilla and maxillary dentition moved antero-inferiorly, the mandibld and mandibular dentition moved postero-interiorly and palatal plane rotated antero-superiorly by $0.59^{\circ}$. 2. After maxillary protraction, the soft tissue of upper lip moved antero-interiorly with the movement of hard tissue but the antero-posterior position of lower lip was stable in spite of the change of hard tissue. The thickness of upper lip was decreased and that of lower lip was increased after maxillary Protraction. 3. During the retention period, the position of jaws was relatively stable but upper and lower anterior teeth and antero-superiorly rotated palatal plane relapsed to original position. 4. During the retention period, the soft tissue of lips was stable antero-posteriorly and moved mote inferiorly than posttreatment. 5. The correlation coefficients between the postion of upper and lower incisal edge and that position of lips were high, especially in horizontal change.

• The Journal of the Korean bone and joint tumor society
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• v.11 no.2
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• pp.141-147
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• 2005

Purpose: The most important thing in curing Malignant melanoma is surgical excision, operating method is wide excision. The author et al. studied 5-year survival rate of each stage and appropriate surgical margin after operating wide excision and immuno-chemotherapy. Materials and methods: From March 1995 to August 2003, wide excision and immunochemotherapy were operated to 35 patients (17 males and 18 females) who were diagnosed as malignant melanoma and followed up. Excision was done around 2 cm from edge of tumor regardless of the size or effected degree of the skin, and flap or full thickness skin graft was used for skin deficit that was not covered after excision. As for immuno-chemotherapy, method that prescribes 400 mg of dacarbazine (DTIC) and 3 million IU of interferone-${\alpha}$ in combination was used. Immuno-chemotherapy was operated to patients in over stage III. We used AJCC stage that was revised in 2002. Local recurrence, local metastasis and distant metastasis were investigated for these patients as well as the 5-year survival rate of each stage. Results: Most frequently 15 cases(42.8%) occurred in foot, 5 cases(14.2%) occured in ankle, 2 cases(5.7%) in leg, 2 cases(5.7%) in thigh and 5 cases(14.2%) in hand. The incidence of each stage were 8 cases(22.8%) in IA, 9 cases(25.7 %) in IB, 4 cases(11.4%) in IIA, 2 cases(5.7%) in IIB, 1 cases(2.8%) in IIIA, 2 cases(5.7%) in IIIB, 2 cases(5.7%) in IIIC and 7 cases(20.0%) in stage IV. 5-year survival rate of each stage were 94.1% in stage I, 66.8% in stage II, 40% in stage III and 14.3% in stage IV. Conclusion: 5-year survival rate of stage IV was low in malignant melanoma. In treatment of malignant melanoma, staging before operation is important as operation methods are different from each stage. We recommend wide excision which remove around 1~3 cm from margin of tumor up to each thickness.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.1
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• pp.35-41
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• 2007

Purpose: To evaluate the effectiveness of a simple and practical shielding device to reduce the fetal dose for a pregnant patient undergoing radiation therapy of brain metastasis. Materials and Methods: The dose to the fetus was evaluated by simulating the treatments using the anthropomorphic phantom. The prescription dose at mid-brain is $300cGy{\times}10$ fractions with 6 MV photon with $18{\times}22cm^2$ field size. The additional shielding devices to reduce the fetal dose are a shielding wall, cerrobend plates and lead (Pb) sheets over acrylic bridge. Various points of measurement with off-field distance were detected by using ion-chamber (30, 40, 50, and 60 cm) with and without the shielding devices and TLD (30, 40, 50, 60, and 70 cm) only with the shielding devices. Results: The doses to the fetus without shielding were 3.20, 3.21, 1.44, 0.90 cGy at the distances of 30, 40, 50, and 60 cm from the treatment field edge. With shielding, the doses were reduced to 0.88, 0.60, 0.35, 0.25 cGy, and the ratio of the shielding effect varied from 70% to 80%. TLD results were 1.8, 1.2, 0.8, 1.2, and 0.8 cGy (70 cm). The total dose to the fetus was expected to be under 1 cGy during the entire treatment. Conclusion: The essential point during radiation therapy of pregnant patient would be minimizing the fetal dose. 10 cGy to 20 cGy is the threshold dose for fetal radiation effects. Our newly developed device reduced the fetal dose far below the safe level. Therefore, our additional shielding devices are useful and effective to reduce the fetal dose.

• Radiation Oncology Journal
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• v.23 no.4
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• pp.230-235
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• 2005

Purpose: To evaluate the contralateral breast dose using a virtual wedge compared with that using a Physical wedge and an open beam in a Siemens linear accelerator. Materials and Methods: The contralateral breast dose was measured using diodes placed on a humanoid phantom. Diodes were placed at 5.5 cm (position 1), 9.5 cm (position 2), and 14 cm (position 3) along the medial-lateral line from the medial edge of the treatment field. A 6-MV photon beam was used with tangential irradiation technique at 50 and 230 degrees of gantry angle. Asymmetrically collimated $17{\times}10cm$ field was used. for the first set of experiment, four treatment set-ups were used, which were an open medial beam with a 30-degree wedged lateral beam (physical and virtual wedges, respectively) and a 15-degree wedged medial beam with a 15-degree wedged lateral beam (physical and virtual wedges, respectively). The second set of experiment consists of setting with medial beam without wedge, a 15-degree wedge, and a 50-degree wedge (physical and virtual wedges, respectively). Identical monitor units were delivered. Each set of experiment was repeated for three times. Results: In the first set of experiment, the contralateral breast dose was the highest at the position 1 and decreased in order of the position 2 and 3. The contralateral breast dose was reduced with open beam on the medial side ($2.70{\pm}1.46%$) compared to medial beam with a wedge (both physical and virtual) ($3.25{\pm}1.59%$). The differences were larger with a physical wedge ($0.99{\pm}0.18%$) than a virtual wedge ($0.10{\pm}0.01%$) at all positions. The use of a virtual wedge reduced the contralateral breast dose by 0.12% to 1.20% of the proscribed dose compared to a physical wedge with same technique. In the second experiment, the contralateral breast dose decreased in order of the open beam, the virtual wedge, and the physical wedge at the position 1, and it decreased in order of a physical wedge, an open beam, and a virtual wedge at the position 2 and 3. Conclusion: The virtual wedge equipped in a Siemens linear accelerator was found to be useful in reducing dose to the contralateral breast. Our additional finding was that the surface dose distribution from the Siemens accelerator was different from a Varian accelerator.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.3
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• pp.179-185
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• 2009

In this research, the removal capacity of Cr(VI) by the reused powdered wastes (RPW) containing aluminium oxides was studied. As a pre-treatment process for the preparation of calcined wastes, calcination was conducted at $550^{\circ}C$ to remove organic fraction in the raw wastes. In order to study the adsorption trend of Cr(VI) ions from aqueous solutions, the pH-edge adsorption, adsorption kinetic and adsorption isotherm were investigated using a batch reactor in the presence of four different background electrolytes($NO_3\;^-,\;CO_3\;^{2-},\;SO_4\;^{2-},\;PO_4\;^{3-}$). Cr(VI) adsorption was greatly reduced in the presence of $SO_4\;^{2-}$ and $PO_4\;^{3-}$ over the entire pH range. Meanwhile the inhibition effect by $NO_3\;^-$ and $CO_3\;^{2-}$ was relatively lower than that by $SO_4\;^{2-}$ and $PO_4\;^{3-}$. Cr(VI) adsorption was maximum around pH 4.5 in the presence of $NO_3\;^-$ and $CO_3\;^{2-}$. As the concentration of background electrolytes increased, Cr(VI) adsorption decreased. This result mightly suggests that adsorption between the surface of RPW and Cr(VI) occurs through outer-sphere complex. Cr(VI) adsorption onto the RPW was well described by second-order kinetics. From the Langmuir isotherm at initial pH 3, the maximum adsorbed amount of Cr(VI) onto the RPW was 11.1, 10, 3.3, 5 mg/g in the presence of $NO_3\;^-,\;CO_3\;^{2-},\;SO_4\;^{2-}$, and $PO_4\;^{3-}$, respectively.

• Korean Journal of Heritage: History & Science
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• v.52 no.1
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• pp.4-21
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• 2019

In this paper, 23 Silla gold earrings from the sixth and seventhand centuries, excavated from the Yeongnam region, were analyzed. Based on the silver content of the gold plate, they were classified into three types. The classifications included type I(20-50wt%), type II(10-20wt%) and type III (less than 10wt%). In the analysis process, the composition and morphological differences were identified on the surface of the gold plate. In the case of type I and II earrings, it was observed that the fine holes were concentrated in a relatively higher part of the gold content. The causes of the difference in the surface composition of the gold plate were divided into four categories: 1) surface treatment, 2) thermal diffusivity in the manufacturing process, 3) differences in composition of alluvial gold, and 4) the refining method of gold. It is possible that depletion gilding was attempted to increase the gold content while intentionally removing the other metals from the surface of the gold alloy in the portion where the gold deposit is relatively concentrated on the surface of the gold plating. The highest copper content was detected in the earring with the highest gold content of the analyzed earrings, and it was assumed that thermal diffusion had occurred between the gold plate and the metal rod during the manufacturing process rather than intentional addition. Copper was detected only in the thin ring earring type, and copper was not detected in the thick ring earring type or pendant type. It also proves that this earring has a high degree of tightness at higher temperatures, as there was an invisible edge finish on other earrings and horizontal wrinkles on the gold plate surface. In terms of the material of the gold plate, we examined whether the silver content of the gold plate was natural gold or added by alloy through analyzing the alluvial gold collected in the region. As a result of the analysis, it was found that on average about 13wt% of silver is included. This suggests that type II is natural gold, type III is refined gold, and type I seems to have been alloyed with natural gold. Here, we investigated the refining method introduced in the ancient literature, both at home and abroad, about the possibility of alloying silver after the refining process of type III earrings and then making pure gold. It was found that from ancient refining methods, silver which had been present in the natural gold was removed by reacting and combining with silver chloride or silver sulfide, and long-term efforts and techniques were required to obtain pure gold through this method. Therefore, it was concluded that the possibility of adding a small amount of silver in order to increase strength after making pure gold through a refining process is low.