• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10a
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• pp.9-18
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• 2003

A method for rapid propagation of mature Jack fruit was developed. Four types of explants (mature embryos, apical meristems of young seedlings, apices from mature plants and nodal segments) were used. It has been found 88% of young apical meristems produced shoots in Campbell and Durzan (CD) medium compared to 60% in Murashige and Skoog (MS) medium. Only 1/3 of them produced multiple shoots. Shoot idtiation from nodal segments was very rare. Mature apices produced callus. Although removed of the sheathing cover around mature buds enhanced the shoot initiation but success rate was low in growth regulator free medium. Embryos respond to the CD medium but not to the MS medium. Embryos from seeds soaked in water for 24 hours produced shoots after 8 weeks of incubation and the success rate was 70% while embryos from dry seeds only produced roots. There was no significant effect of cold storage (refrigeration) for 7 days on shoot initiation from mature embryos (65%) but the ability for shoot induction declines with storage time (55% after 21 days of cold storage). Mature axillary buds were established in Modified Campbell and Durzan (CD) medium supplemented with 0.5mg/1 and IBA. There was a significant difference in the growth performance of shoots according to the period of the year in which explants were collected. Highest (60%) was observed in November-January period. It was only 30% when the explants were collected in February-April or May-July and decreased to 20% in August-October. The shoots produced in November-January showed a higher vigor than those produced in other months. Since Jak fruit show seasonal changes in fruit bearing and shedding of leaves, it can be suggested that the difference in growth performances of tissues cultured in artificial culture media would have been affected by endogenous rhythms.

• Current Optics and Photonics
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• v.2 no.6
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• pp.499-507
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• 2018

For the spatiotemporally aligned observation of photothrombosis induction and transient variations of in vivo brain stroke, we developed a novel photothrombosis inducing system compatible to a magnetic resonance imaging (MRI) system using nonmagnetic stereotaxic equipment. From the spatial point of view, the system provides a more reliable level of reproducibility of the photothrombosis in each brain. From the temporal point of view, from T1- and T2-weighted in vivo MR (magnetic resonance) images, the transient variations such as incidence, location, and size of the thrombosis are measured quantitatively. In addition, the final variation is observed in the ex vivo brain by TTC (Triphenyltetrazolium chloride) staining based on histological assay and utilized for the verification of the MR images. From the experimental result of the rat brain, the proposed system shows more reliable characteristics for transient variations of brain strokes.

• Journal of dental hygiene science
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• v.19 no.3
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• pp.154-161
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• 2019

Background: The market for vitamin drinks is expanding both in Korea and worldwide. However, it was difficult to find studies regarding the possibility of tooth erosion induction due to vitamin drinks. The purpose of the present in vitro study was to evaluate the effect of tooth erosion caused by a few commercial vitamin beverages on bovine teeth enamel in terms of erosion depth and fluorescence loss. Methods: Three experimental groups (vitamin drinks), a positive control group (Coca-Cola), and a negative control group (mineral water) were established. Each group consisted of 5 specimens obtained from sound bovine teeth. The pH and titratable acidity of beverages were measured. Specimens were immersed in the beverages and artificial saliva for 6 and 18 hours, respectively. This cycle was repeated for 5 days. The depth of the tooth loss caused by tooth erosion (erosion depth) and maximum loss of fluorescence (Max ${\Delta}F$) were measured using the microscope and quantified light-induced fluorescence-digital, respectively. For the statistical analysis, the Kruskal-Wallis test and ANOVA were used to compare the erosion depth and Max ${\Delta}F$ of the enamel surfaces. In addition, Spearman correlations were estimated. Results: The pH of the three vitamin beverages ranged from 2.65 to 3.01, which is similar to that of the positive control group. All beverages, except mineral water, had sugar and acidic ingredients. Vitamin drinks and the positive control, Coca-Cola, caused tooth erosion lesions, and showed significant differences in erosion depth compared to mineral water (p<0.05). The vitamin beverages with low pH were associated with high erosion depth and Max ${\Delta}F$. Conclusion: Vitamin drinks have the potential to cause tooth erosion.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1138-1143
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• 2020

MRI scans in the abdominal area are difficult to achieve optimal images due to artificial respiration. Among 45 patients (male:female = 30:15) who underwent abdominal MRI examination, a metronome-based examination method was studied for patients whose breathing is difficult and difficult to examine. The images examined without using a metronome were divided into group A, and the images examined using a metronome were divided into group B. Image quality improvement (30%) and inspection time (approximately 50 seconds) were reduced in images using metronome. During abdominal magnetic resonance imaging (ABD MRI), the images examined using a metronome had differences in quality and examination time compared to the unused images. It is more effective to use a metronome brace that controls the patient's respiratory rate during abdominal magnetic resonance imaging under respiratory induction in patients with difficulty in respiratory-gated.

• Journal of Microbiology and Biotechnology
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• v.32 no.2
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• pp.238-247
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• 2022

Since the skin covers most surfaces of the body, it is susceptible to damage, which can be fatal depending on the degree of injury to the skin because it defends against external attack and protects internal structures. Various types of artificial skin are being studied for transplantation to repair damaged skin, and recently, the production of replaceable skin using three-dimensional (3D) bioprinting technology has also been investigated. In this study, skin tissue was produced using a 3D bioprinter with human skin cell lines and cells extracted from mouse skin, and the printing conditions were optimized. Gelatin was used as a bioink, and fibrinogen and alginate were used for tissue hardening after printing. Printed skin tissue maintained a survival rate of 90% or more when cultured for 14 days. Culture conditions were established using 8 mM calcium chloride treatment and the skin tissue was exposed to air to optimize epidermal cell differentiation. The skin tissue was cultured for 14 days after differentiation induction by this optimized culture method, and immunofluorescent staining was performed using epidermal cell differentiation markers to investigate whether the epidermal cells had differentiated. After differentiation, loricrin, which is normally found in terminally differentiated epidermal cells, was observed in the cells at the tip of the epidermal layer, and cytokeratin 14 was expressed in the lower cells of the epidermis layer. Collectively, this study may provide optimized conditions for bioprinting and keratinization for three-dimensional skin production.

• Journal of Forest and Environmental Science
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• v.37 no.4
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• pp.323-330
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• 2021

Zygotic embryo culture was performed to propagate evergreen oak, Quercus myrsinifolia, which has recalcitrant seeds and is difficult to propagate by cuttings. Zygotic embryos appeared in WPM medium after 14 days, and after 56 days, they developed into complete plants with cotyledons and roots. The medium suitable for zygotic embryo culture was 1/4 WPM medium, showing a shoot growth of 2.43 cm and root growth of 8.7 cm after 8 weeks of culture. As a result of investigating the effect of GA₃ on the growth of plants germinated from zygotic embryos through GA₃ treatment, the best growth was shown in 0.5 mg/l GA₃ treatment. The in vitro rooting and growth of IBA-treated zygotic embryo-derived plants were good in the 0.5 mg/l IBA treatment and rooting and shoot growth were not observed at higher concentrations. And the callus induction rate also increased as the concentration of IBA increased. Plants grown in vitro were transferred to a plastic pot containing artificial soil and acclimatized in a greenhouse for about 4 weeks, resulting in more than 90% survival. As a result of this study, the zygotic embryo culture method was confirmed to be effective for mass propagation of Q. myrsinifolia. The results of this study are expected to contribute significantly to the mass propagation of elite Q. myrsinifolia.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.65.2-65
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• 2003

To protect the plant against several soil-borne pathogens, we are currently constructing disease-resistant transgenic root stock for the growth of cucurbitaceae vegetable plants, watermelon and gourd. We made a watermelon cDNA library from Cladosporium cucumerinum-Infected leaves for substractive hybriazation and differential screening. We isolated the several pathogen inducible cDNA clones, such as caffeoyl-CoA-methyltransferase, LAA induced protein, receptor-like kinase homolog, hydroxyproline-rich glycoprotein, catalase, calmodulin binding protein, mitochondrial ATPase beta subunit, methyl tRNA synthetase and WRKY transcription factors. We previously obtained CaMADS in pepper and galactinol synthase ( CsGolS) in cucumber that were confirmed to be related with disease-resistance. CaMADS and CsGolS2 were transformed into the inbred line 'GO701-2' gourd, the inbred line '6-2-2' watermelon and the Kong-dye watermelon by Agrobacterium tumerfaciens LBA4404. Plant growth regulators (zeatin, BAP and IAA) were used for shoot regeneration and root induction for optimal condition. Putative transgenic plants were selected in medium containing 100mg/L kanamycin and integration of the CaMADS and CsGO/S2 into the genomic DNA were demonstrated by the PCR analysis. We isolated major soil-borne pathogens, such as Monosporascus cannonballus, Didymella bryoniae, Cladosporium cuvumerinum from the cultivation area of watermelon or root stock, and successfully established artificial inoculation method for each pathogen. This work was supported by a grant from BioGreen 21 program, Rural Development Administration, Republic of Korea.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.2
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• pp.111-116
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• 2023

We provided general anesthesia management to a patient with advanced atrioventricular block, which was discovered in the remote period after open-heart surgery. A 21-year-old man with Noonan syndrome was scheduled to undergo excision of a median intramandibular tumor. At 2 months of age, the patient underwent endocardial repair for congenital heart disease. During our preoperative examination, an atrioventricular block was detected, which had not been previously noted. Emergency drugs were administered, and a transcutaneous pacemaker was placed. During anesthesia induction, mask ventilation was easy, and intubation was performed smoothly using a video laryngoscope. The transcutaneous pacemaker was activated in demand mode at a pacing rate of 50 cycles/min approximately throughout the anesthesia time, and the hemodynamic status remained stable. The effect of intraoperatively administered atropine was brief, lasting only a few seconds. Although body movements due to thoracoabdominal muscle spasm were observed during pacemaker activation, they did not interfere with surgery. In postoperative patients with congenital heart disease, an atrioventricular block may be identified in the remote period, and preoperative evaluation should be based on this possibility. In addition, during anesthesia management, it is important to prepare multiple measures to maintain hemodynamic status.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.47.3-48
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• 2021

We studied the large scale dynamo process in a system forced by helical magnetic field. The dynamo process is basically nonlinear, but can be linearized with 𝛼&𝛽 coefficients and large scale magnetic field $\bar{B}$. This is very useful to the investigation of solar (stellar) dynamo. A coupled semi-analytic equations based on statistical mechanics are used to investigate the exact evolution of 𝛼&𝛽. This equation set needs only magnetic helicity ${\bar{H}}_M({\equiv}{\langle}{\bar{A}}{\cdot}{\bar{B}}{\rangle},\;{\bar{B}}={\nabla}{\times}{\bar{A}})$ and magnetic energy ${\bar{E}}_M({\equiv}{\langle}{\bar{B}}^2{\rangle}/2)$. They are fundamental physics quantities that can be obtained from the dynamo simulation or observation without any artificial modification or assumption. 𝛼 effect is thought to be related to magnetic field amplification. However, in reality the averaged 𝛼 effect decreases very quickly without a significant contribution to ${\bar{B}}$ field amplification. Conversely, 𝛽 effect contributing to the magnetic diffusion maintains a negative value, which plays a key role in the amplification with Laplacian ∇²(= - k²) for the large scale regime. In addition, negative magnetic diffusion accounts for the attenuation of plasma kinetic energy E_V(= 〈 U² 〉/2) (U: plasma velocity) when the system is saturated. The negative magnetic diffusion is from the interaction of advective term - U • ∇ B from magnetic induction equation and the helical velocity field. In more detail, when 'U' is divided into the poloidal component U_pol and toroidal one U_tor in the absence of reflection symmetry, they interact with - B • ∇ U and - U • ∇ B from ∇ × 〈 U × B 〉 leading to 𝛼 effect and (negative) 𝛽 effect, respectively. We discussed this process using the theoretical method and intuitive field structure model supported by the simulation result.

• Korean Journal of Community Nutrition
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• v.28 no.3
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• pp.181-191
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• 2023

Objectives: The incidence of inflammatory bowel disease (IBD) is increasing globally, and excessive added sugar consumption has been identified as one of the contributing factors. In the context of IBD, it is essential to explore functional sweeteners that can improve metabolic health and minimize the risk of IBD-related symptoms. This review article aims to shed light on the effects of natural mono- and di-saccharides as alternative sweeteners, specifically focusing on potential benefits for IBD. Methods: A comprehensive literature review was performed using PubMed and Google Scholar databases with articles published after the year 2000. The search terms 'IBD', 'added sugar', 'sweeteners', 'mono-saccharide', and 'di-saccharide' were combined to retrieve relevant articles. A total of 21 manuscripts, aligning with the objectives of the study, were selected. Papers focusing on artificial or high-intensity sweeteners were excluded to ensure relevant literature selection. Results: Multiple studies have emphasized the association between the high consumption of added sugars such as simple sugars and the increased risk of developing IBD. This is suggested to be attributed to the induction of pro-inflammatory cytokine productions and dysbiosis of the gut microbiota. Consequently, there is a growing demand for safe and functional sweeteners, in particular mono- and di-saccharides, that can serve as alternatives for IBD patients. Those functional sweeteners regulate inflammation, oxidative stress, and Intestinal barrier protection, and restore microbiome profiles in various IBD models including cells, animals, and humans. Conclusions: Understanding these mechanisms resolves the link between how sugar consumption and IBD, and highlights the beneficial effects of natural alternative sweeteners on IBD when they were administered by itself or as a replacement for simple sugar. Further, exploration of this relationship leads us to recognize the necessity of natural alternative sweeteners in dietary planning. This knowledge could potentially lead to more effective dietary strategies for individuals with IBD.