• Journal of Life Science
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• v.34 no.8
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• pp.540-547
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• 2024

The continuous use of polymer materials has exacerbated waste and environmental challenges, spurring a growing interest in eco-friendly polymers, especially biodegradable polymers. These polymers are gaining attention for their potential as antimicrobial agents, particularly in fields like food packaging a need further underscored by the recent COVID-19 pandemic. This study focuses on the development of an antibacterial polymer by combining poly-butylene adipate terephthalate (PBAT) with zinc pyrithione (ZnPt). The antibacterial properties were assessed through turbidity analysis, the shaking flask method, and the film adhesion method. The antibacterial activities of the composites with varying ZnPt% (w/w) contents (0, 0.1, 0.3, and 0.5) were evaluated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Results revealed that even at a low concentration of 0.1% (w/w), the composites demonstrated significant antibacterial activity against both Gram-positive bacteria (S. aureus) and Gram-negative bacteria (E. coli). Composites with ZnPt concentrations of 0.3% (w/w) or higher achieved over 99.999% antibacterial efficacy. Field emission scanning electron microscopy (FE-SEM) analysis of the fracture surfaces of the composites confirmed the uniform distribution of ZnPt particles, ranging from 1-4 ㎛. Further FE-SEM analysis of bacterial suspensions exposed to the composite surfaces showed clear evidence of cell wall destruction in both E. coli and S. aureus. As an antimicrobial biodegradable polymer, PBAT-ZnPt composites show great promise for applications in various sectors, including food packaging.

• International Journal of Molecular Medicine
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• v.43 no.2
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• pp.1105-1113
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• 2019

Epigenetic modifier lysine demethylase 3a (Kdm3a) specifically demethylates mono- and di-methylated ninth lysine of histone 3 and belongs to the Jumonji domain-containing group of demethylases. Kdm3a serves roles during various biological and pathophysiological processes, including spermatogenesis and metabolism, determination of sex, androgen receptor-mediated transcription and embryonic carcinoma cell differentiation. In the present study, physiological functions of Kdm3a were evaluated during embryogenesis of Xenopus laevis. Spatiotemporal expression pattern indicated that kdm3a exhibited its expression from early embryonic stages until tadpole stage, however considerable increase of kdm3a expression was observed during the neurula stage of Xenopus development. Depleting kdm3a using kdm3a antisense morpholino oligonucleotides induced anomalies, including head deformities, small-sized eyes and abnormal pigmentation. Whole-mount in situ hybridization results demonstrated that kdm3a knockdown was associated with defects in neural crest migration. Further, quantitative polymerase chain reaction revealed abnormal expression of neural markers in kdm3a morphants. RNA sequencing of kdm3a morphants indicated that kdm3a was implicated in mesoderm formation, cell adhesion and metabolic processes of embryonic development. In conclusion, the results of the present study indicated that Kdm3a may serve a role in neural development during Xenopus embryogenesis and may be targeted for treatment of developmental disorders. Further investigation is required to elucidate the molecular mechanism underlying the regulation of neural development by Kdm3a.

• Journal of the Korean Electrochemical Society
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• v.27 no.3
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• pp.97-104
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• 2024

The electrodes of commercialized lithium secondary batteries are manufactured through a wet coating process, and the drying process (DC) is a very important factor as to electrode production speed and process cost. In this study, silicon anodes were manufactured under high-temperature (180 ℃) and low-temperature (50 ℃) DC to investigate the quality and the electrochemical performance of Si-electrodes according to DC. High-temperature DC can quickly evaporate the solvent in the Si-electrode slurry, improving the electrode production rate. However, this also causes the electrode composite to peel off from the current collector. As a result, the Si-electrode's adhesion weakened, and the electrode coating's quality deteriorated. In addition, the Si-electrode manufactured under high-temperature was found to have a thicker composite material than the Si-electrode manufactured under low-temperature. Si-electrodes manufactured under high-temperature had higher sheet resistance and lower electrical conductivity than those manufactured under low-temperature. Consequently, the Si-electrode manufactured under low-temperature showed 152.5% superior cycle performance compared to the Si-electrode manufactured under high-temperature. (Discharge capacities of Si-electrodes manufactured under high-temperature and low-temperature DC were 844 and 1287 mAh g^-1, respectively, after 300 cycles). Establishing the DC of Si-electrodes can easily provide new perspectives to improve the quality and stability of Si-electrodes.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.312-318
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• 2023

In recent years, fine and yellow dust pollution has become serious in Korea and has negatively affected crop production. Particulate matter (PM) adheres to greenhouse coverings, and it reduces the amount of solar radiation transmitted into a greenhouse. A reduction in light transmittance can have a direct effect on crop photosynthesis and an indirect effect on air temperature in a greenhouse, which can lead to differences in crop yield. The objectives of this study were to investigate the changes in light transmittance of different cover materials by PM and to determine the changes in cucumber growth in a greenhouse due to reduced light transmittance. We measured the changes in light transmittance of polyethylene (PE) and polyolefin (PO) films in the PM generation chambers. Also, cucumber plants were cultivated in a greenhouse with four different light reduction treatments (0, 10, 20, and 30% reduction of light transmittance). The initial light transmittance of PO film was higher than that of PE film and the decrease in light transmittance of PO film due to PM was less than that of PE film. The vegetative growth of cucumber was promoted under the reduced light transmittance treatments; however, the yield of cucumber was highest in the control (0% reduction of light transmittance). From the results, we confirmed that PO film was less PM adhesion and that cucumber yield during the spring season can be reduced by the reduction in light transmittance due to PM.

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.3
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• pp.314-321
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• 2024

Due to the depletion of natural aggregate resources, the use of recycled aggregates became an urgent issue. Microcracks generated during production of recycled aggregate and cement paste attached to the surface of aggregate have been the biggest obstacles to promote the use of recycled aggregate. To alleviate such problem, this study attempted the spray and immersion treatment of recycled fine aggregate using mono-ammonium phosphate solution, which is known to be effective for reducing the pH of recycled aggregate. The changes in physical properties before and after treatment were observed, and the compressive strength of mortar specimen was evaluated. According to the experimental results, the absorption capacity of the recycled fine aggregate increased with reduction in pH after mono-ammunium phosphate treatment. Calcium hydroxide and ettringite was removed, and skeletal density of recycled fine aggregate increased due to the formation of hydroxyapatite. Despite the increase in absorption capacity, the compressive strength of the mortar increased and it seems to be associated with the increase in adhesion strength at the interface between cement paste and recycled fine aggregate. When the concentration of ammonium monophosphate aqueous solution was excessive (immersion: 15% and 20%, spraying 20%), the compressive strength of the mortar decreased, which seemed to be related to the increase in the absorption capacity caused by the the excessive dissolution of the hydration products such as portlandite and ettringite.

• Journal of dental hygiene science
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• v.24 no.3
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• pp.181-189
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• 2024

Background: Focal adhesions (FAs) is the most important process in the first step of osseointegration between preosteoblasts and titanium (Ti). FAs improvement and pre-osteoblasts cell proliferation leads to successful Ti-based dental implants. This study aimed to confirm the applicability of rosmarinic acid (RA) as a functional substance for improving FAs and cell proliferation of MC3T3-E1 preosteoblasts on Ti surfaces during the first stage of osseointegration for successful Ti-based dental implants. Methods: We used MC3T3-E1 preosteoblasts on Ti discs incubated in a medium supplemented with or without 14 ㎍/ml to decipher the effects of RA on FAs and cell proliferation. FAs and proliferation of MC3T3-E1 cells on Ti discs were assessed via MTT assay. Actin-labeled cells and paxillin contacts were observed and imaged by fluorescent microscopy, and the associated signaling pathways were revealed through western blot analysis. Results: In RA-treated MC3T3-E1 cells on Ti discs, FAs between MC3T3-E1 preosteoblasts and Ti surfaces and the expression of focal adhesion kinase (FAK), phosphorylated FAK and paxillin proteins and filamentous-actin formation increased. RA increased the proliferation of MC3T3-E1 preosteoblasts on the Ti surface as well as the expression of Grab2, Ras, pERK1/2, and ERK1/2. In addition, the expression of secretory leukocyte protease inhibitor and thymosin b4, known as nanomolecules that enhance the interaction between implanted Ti materials and preosteoblasts in the RA-treated MC3T3-E1 preosteoblasts, increased. RA not only increased the FAs of MC3T3-E1 preosteoblasts on the Ti surface through the FAK/Paxillin signaling pathway, but also increased cell proliferation and mitosis through the FAK/Grab2/Ras/ERK1/2 signaling pathway. Conclusion: RA can be applied as an effective functional substrate to improve the FAs and proliferation of MC3T3-E1 preosteoblats on Ti surfaces, which are essential in the first step of osseointegration between implanted Ti and bone tissue for the clinical success of Ti based dental implants.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.129-136
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• 2011

Recently studies on functional concrete with a photocatalytic material such as $TiO_2$ have actively been carried out in order to remove air pollutants. The absorbtion of $TiO_2$ from those studies is applied by it being directly mixed into concrete or by suspension coated on the surface. When it comes to the effectiveness, the former process is less than that of the latter compared with the $TiO_2$ use. As a result, the direct coating of $TiO_2$ on materials' surface is more used for effectiveness. The Surface spread of it needs to have a more than $400^{\circ}C$ heat treat done to stimulate the activation and adhesion of photocatalysis. Heat treat consequently leads hydration products in concrete to be dehydrated and shrunk and is the cause of cracking. The study produces $TiO_2$ used Sol-gel method which enables it to be coated with a low temperature treat, applies it to pearlite using Lightweight Aggregate Concrete fixed with a low temperature treat and evaluates the spread performance of it. In addition to this, the size of pearlite is divided into two types: One is 2.5 mm to 5.0 mm and the other is more than 5.0 mm for the benefit of finding out the removal characteristics of $CH_3CHO$ whether they are affected by pearlite size, mixing method and ratio with $TiO_2$ and elapsed time. The result of this experiment shows that although $TiO_2$ produced by Sol-gel method is treated with 120 temperature, it maintains a high spread rate on the XRF(X ray Florescence) quantitative analysis which ranks $TiO_2$ 38 percent, $SiO_2$ 29 percent and CaO 18 percent. In the size of perlite from 2.5 mm to 5.0 mm, the removal characteristic of $CH_3CHO$ from a low temperature heated Lightweight concrete appears 20 percent higher when $TiO_2$ with Sol-gel method is spreaded on the 7 percent of surface. In other words, the removal rate is 94 percent compared with the 72 percent where $TiO_2$ is mixed in 10 percent surface. In more than 5.0 mm sized perlite, the removal rate of $CH_3CHO$, when $TiO_2$ is mixed with 10 percent, is 69 percent, which is similar with that of the previous case. It suggests that the size of pearlite has little effects on the removal rate of $CH_3CHO$. In terms of Elapsed time, the removal characteristic seems apparent at the early stage, where the average removal rate for the first 10 hours takes up 84 percent compared with that of 20 hours.

• Polymer(Korea)
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• v.36 no.6
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• pp.768-775
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• 2012

Alginate, obtained from the seaweeds, is a widely used biomaterial for cell transplantation, since its positive effect on viability of capsulized cells and its easier encapsulation capability of living cells. Demineralized bone powder (DBP), derived from the natural bone tissue, is widely applied for clinical trials for its low rate of reaction and antigenicity. A chondrocyte was seeded into an alginate with DBP of different contents, and a microcapsule was produced. The adhesion and proliferation of cells was observed through the MTT analysis, and the PCR was applied to estimate the content of the glycosaminoglycan (sGAG) and collagen, and confirm the specific genetic pattern of the chondrocytes. Also, the alginate microcapsule where the chondrocyte is seeded was extracted after transplantation under the skin of a nude mouse, and was immunochemically stained. The experimental result confirmed that the alginate microcapsule containing 1% of DBP not only showed the highest proliferation of cell but had a positive effect of chondrocytes by the interaction between the alginates and the growth factor in DBP. It can be expected that the microcapsule with application of the alginates and DBP might be an appropriate scaffold for tissue engineering.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.681-686
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• 2010

Background: A chest computed-tomography has become more prevalent so that it is more common to detect small sized pulmonary nodules that have not been found in previous simple chest x-ray. If those detected nodules are undersized or located in pulmonary parenchyma, it is difficult to accomplish a biopsy since it is vulnerable to explore them either grossly or digitally. Thus, in our hospital, a thoracoscopic pulmonary wedge resection was performed after locating a lesion by means of hook wire with CT-guided. Material and Method: 31 patients (17 males and 14 female patients) from December in 2006 to June in 2010 became our subjects; their 34 pulmonary nodules were subjected to the thoracoscopic pulmonary wedge resection after locating a lesion by means of hook wire with CT-guided. Also we analyzed a possibility of hook wire dislocation, a frequency of conversion to open thoracotomy, time consumed to operation after location of a lesion, operation time, post operation complication, and histological diagnosis of the lesion. Result: 12 of 34 cases were ground glass lesion, whereas 22 cases of them were solitary pulmonary lesion. The median value of the lesion was 8mm in size (range: 3 to 23 mm), while the median value was 12.5 mm in depth (range: 1 to 34 mm). The median value of time consumed from location of the lesion to anesthetic induction was 86.5 minutes (41~473 minutes); furthermore the mean value of operation time was 103 minutes (25~345 minutes). Intrathoracic wire dislocation was found in one case, but a target lesion was successfully excised. Open thoracotomy was performed in four cases due to pleural adhesion. However, there was no case of conversion to open thoracotomy due to failure to detect a target lesion. In histological diagnosis, metastatic cancer were found in 15 cases, which were the most common, primary lung cancer were in 9 cases, non-specific inflammation were in 3 cases, tuberculosis inflammation were in 2 cases, lymph nodes were in 2 cases, active tuberculosis were in 1 case, atypical adenomatous hyperplasia was in 1 case and normal lung parenchymal finding was in 1 case, respectively. Conclusion: In our hospital, in order to accomplish a precise histological diagnosis of ground-glass lesion and pulmonary nodules in lung parenchyma, location of pulmonary nodules were exactly located with hook wire under chest computed-tomography, which was followed by lung biopsy. We concluded that this was an accurate, minimally invasive and valuable method to minimize the complications and increase of cost of medical service provided.

• Journal of the Korean Arthroscopy Society
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• v.10 no.1
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• pp.61-69
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• 2006

Purpose: Open lateral release and complete lateral release have been conducted as a surgical method in patients with patellofemoral malalignment. But authors sought to find out the best method by conducting selective release, with minimal excision of the involved lesion, and comparative analyzing the result, as postoperative satisfaction and complication. Materials and Methods: Over the 68 patients of 90 cases who underwent arthroscopic release, among 94 patients of 129 cases who underwent lateral retinacular release, from January 1993 to June 1998 were followed up prospectively. A radiological evaluation of patellar inclination, patellar tilt, congruence angle, and Q-angle and a clinical evaluation of HSS-Knee score and modified patellar score were used for analysis data before operation and data at 1 year and 5 year after operation. Results: According to the radiologic evaluation, the patellar tilt and translation revealed improvement of the results, from $13.4^{\circ}$ and 12.1mm to $3.6^{\circ}$ and 3.8mm with arthroscopic lateral complete release, and from $12.3^{\circ}$ and 11.2mm to $4.8^{\circ}$ and 5.2mm with selective release, and from $13.6^{\circ}$ and 12.3mm to $3.3^{\circ}$ and 3mm with open release. But they were not significantly related to the clinical results. HSS-Knee score was 84.2%(48/57), 81.8%(27/33), 82.1%(32/39) and modified patellar score was 82.5%(47/57), 81.8%(27/33), 82.1%(32/39) respectively, which revealed satisfactory results. And no significant difference among the operative methods were shown. Conclusion: Arthroscopic lateral retinacular release which is one of the surgical method for patellofemoral malalignment enhances rehabilitation and satisfaction of the patient, by releasing the involved retinaculum within lesser surgical extent, compared to open and complete lateral release without complications such as adhesion.