• Clean Technology
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• v.28 no.3
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• pp.203-209
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• 2022

An environmental evaluation was conducted by employing LCA methodology for a mechanical seal manufacturing process that uses recycled silicon recovered from end-of-cycle PV modules. The recycled silicon was purified and reacted with carbon to synthesize β-SiC particles. Then the particles underwent compression molding, calcination and heat treatment to produce a product. Field data were collected and the potential environmental impacts of each stage were calculated using the LCI DB of the Ministry of Environment. The assessment was based on 6 categories, which were abiotic resource depletion, acidification, eutrophication, global warming, ozone depletion and photochemical oxidant creation. The environmental impacts by category were 45 kg CO₂ for global warming and 2.23 kg C₂H₄ for photochemical oxide creation, and the overall environmental impact by photochemical oxide creation, resource depletion and global warming had a high contribution of 98.7% based on weighted analysis. The wet process of fine grinding and mixing the raw silicon and carbon, and SiC granulation were major factors that caused the environmental impacts. These impacts need to be reduced by converting to a dry process and using a system to recover and reuse the solvent emitted to the atmosphere. It was analyzed that the environmental impacts of resource depletion and global warming decreased by 53.9% and 60.7%, respectively, by recycling silicon from end-of-cycle PV modules. Weighted analysis showed that the overall environmental impact decreased by 27%, and the LCA analysis confirmed that recycling waste modules could be a major means of resource saving and realizing carbon neutrality.

• Resources Recycling
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• v.31 no.2
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• pp.3-11
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• 2022

Owing to the global development of high-strength alloys and renewable energy industries, the demand for vanadium, a key raw material in these industries, is expected to increase. Until now, vanadium has been recovered as a by-product of the industry, but interest in its direct recovery from minerals has increasing with its significantly increasing demand. In particular, the recovery of vanadium from stone coal ore and vanadium titano-magnetite (VTM) containing vanadium has been actively researched in China, which has the largest reserves and production of vanadium in the world. In Korea, a large amount of VTM also occurs in the northern part of Gyeonggi-do, and fundamental research and technical development is being conducted to recover vanadium. It is necessary to understand the current status of the separation technology used worldwide to satisfy the demand for metals such as vanadium, which currently depends on imports.

• Journal of Periodontal and Implant Science
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• v.51 no.6
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• pp.398-408
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• 2021

Purpose: In this study, we aimed to evaluate the clinical validity of the modified tunneling technique using minimal soft tissue harvesting and volume-stable collagen matrix in the anterior mandible. Methods: In total, 27 anterior mandibular teeth and palatal donor sites in 17 patients with ≥1 mm of gingival recession (GR) were analyzed before and after root coverage. For the recipient sites, vertical vestibular incisions were made in the interdental area and a subperiosteal tunnel was created with an elevator. After both sides of the marginal gingiva were tied to one another, a prepared connective tissue graft and volume-stable collagen matrix were inserted through the vestibular vertical incision and were fixed with resorbable suture material. The root coverage results of the recipient site were measured at baseline (T₀), 3 weeks (T₃), 12 weeks (T₁₂), and the latest visit (T_l). For palatal donor sites, a free gingival graft from a pre-decided area avoiding the main trunk of the greater palatine artery was harvested using a prefabricated surgical template at a depth of 2 mm after de-epithelization using a rotating bur. In each patient, the clinical and volumetric changes at the donor sites between T₀ and T₃ were measured. Results: During an average follow-up of 14.5 months, teeth with denuded root lengths of 1-3 mm (n=12), 3-6 mm (n=11), and >6 mm (n=2) achieved root coverage of 97.01%±7.65%, 86.70%±5.66%, and 82.53%±1.39%, respectively. Miller classification I (n=12), II (n=10), and III (n=3) teeth showed mean coverage rates of 97.01%±7.65%, 86.91%±5.90%, and 83.19%±1.62%, respectively. At the donor sites, an average defect depth of 1.41 mm (70.5%) recovered in 3 weeks, and the wounds were epithelized completely in all cases. Conclusions: The modified tunneling technique in this study is a promising treatment modality for overcoming GR in the anterior mandible.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.292-297
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• 2022

Direct injection of CRISPR/Cas9 into zygotes enables the production of genetically modified nonhuman primates (NHPs) essential for modeling specific human diseases, such as Usher syndrome, and for developing novel therapeutic strategies. Usher syndrome is a rare genetic disease that causes loss of hearing, retinal degeneration, and problems with balance, and is attributed to a mutation in MYO7A, a gene that encodes an uncommon myosin motor protein expressed in the inner ear and retinal photoreceptors. To produce an Usher syndrome type 1B (USH1B) rhesus macaque model, we disrupted the MYO7A gene in developing zygotes. Identification of appropriately edited MYO7A embryos for knockout embryo transfer requires sequence analysis of material recovered from a trophectoderm (TE) cell biopsy. However, the TE biopsy procedure is labor intensive and could adversely impact embryo development. Recent studies have reported using cell-free DNA (cfDNA) from embryo culture media to detect aneuploid embryos in human in vitro fertilization (IVF) clinics. The cfDNA is released from the embryo during cell division or cell death, suggesting that cfDNA may be a viable resource for sequence analysis. Moreover, cfDNA collection is not invasive to the embryo and does not require special tools or expertise. We hypothesized that selection of appropriate edited embryos could be performed by analyzing cfDNA for MYO7A editing in embryo culture medium, and that this method would be advantageous for the subsequent generation of genetically modified NHPs. The purpose of this experiment is to determine whether cfDNA can be used to identify the target gene mutation of CRISPR/Cas9 injected embryos. In this study, we were able to obtain and utilize cfDNA to confirm the mutagenesis of MYO7A, but the method will require further optimization to obtain better accuracy before it can replace the TE biopsy approach.

• Journal of Nutrition and Health
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• v.56 no.6
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• pp.615-628
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• 2023

Purpose: Increasing levels of domestic fine dust (DFD) have emerged as a serious problem that threatens public health by causing chronic respiratory diseases and skin aging. The present study was performed to investigate the inhibitory effects of Gryllus bimaculatus (the two-spotted cricket), which has recently attracted attention as an edible insect in South Korea, on DFD-induced aging and inflammation. Methods: To verify that DFD causes skin aging and investigate the anti-aging effect of an aqueous ethanolic-Gryllus bimaculatus extract (AE-GBE), human diploid fibroblasts (HDF) were treated with 100 ㎍/mL of European reference material (ERM)-CZ100 dust for 24 hrs in the presence or absence of 100 ㎍/ml AE-GBE. Aging and cellular toxicities were assessed by measuring reactive oxygen species (ROS) levels, DNA fragmentation, and β-galactosidase activity. The protein levels of cyclooxygenase (COX) 2, matrix metalloproteinase (MMP)-1, and collagen were measured by western blot, and the mRNA expressions of inflammation-related genes were assayed by quantitative reverse transcriptase polymerase chain reaction. Results: Treatment with ERM-CZ100 induced an aged phenotype in HDF cells, as evidenced by increased ROS levels, DNA fragmentation, and senescence-associated β-galactosidase activity, but cotreatment with AE-GBE significantly reduced these inductions. The mRNA expressions of pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, induced by ERM-CZ100 were also reduced by AE-GBE cotreatment, which also reduced COX2 expression. Moreover, ERM-CZ100-induced MMP-1 expression and reduced collagen type I expression were recovered by AE-GBE treatment. Conclusion: These results suggest that AE-GBE is a potential treatment for domestic fine dust-induced skin inflammation and inflammaging.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.665-669
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• 2023

The crude methylnaphthalene oil (CMNO) contains nitrogen compounds (NCs) such as quinoline (QU), isoquinoline (IQU), and indole (IN). These NCs in the CMNO are treated as impurities contained in the CMNO due to contamination of the atmospheric environment and unpleasant odors. In order to improve the quality of CMNO, this study examined the effect of extraction experimental factors on the reduction of NCs contained in CMNO using CMNO as a raw material and an aqueous formamide solution as a solvent, respectively. The increase in the volume ratio of solvent to feed in initial (S/F)₀ in initial increased the distribution coefficient of NCs and the selectivity of NCs in reference to 2-methylnaphthalene (2MNA). Additionally, an increase in operating temperature (T) increased the distribution coefficient of NCs but conversely decreased selectivity. The compositions of QU, IQU, and IN in the raffinate oil recovered through equilibrium extraction under a constant condition (volume fraction of water to solvent in initial (y_w,0) = 0.1, (S/F)₀ = 9, T = 303 K, liquid-liquid contacting time = 72 h) were reduced by about 58.5 wt%, 61.9 wt%, and 73.4 wt%, respectively, compared to those of CMNO. The formamide extraction method in this study was expected to be an effective reduction method for NCs contained in CMNO.

• Parasites, Hosts and Diseases
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• v.28 no.3
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• pp.183-194
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• 1990

In an attempt to develop prophylactic and therapeutic measures of the intestinal giant-cystic disease caused by Thelohanellus kitauei in the Israel carp, Cyprinus carpio nodus, pathological observations were conducted upon the carps which were hatched in May 1988 and raised in a net cage fish farm at the Soyang lake, managed by Horim Fisheries for the period of 21 months with 1~2 months interval. After a gross inspection of the carps, necropsy was carried out periodically in order to clarify the pathological changes in various internal organs and muscular tissues. Also. the prevalence of the disease was checked during the period from 1988 to 1990. Gross inspections revealed that the infected carps showed some degree of fading in body and gill color, back-emaciation symptoms, reddish anus accompanying erosion and relaxation and pot-belly, as well as discharge of yellowish white mucoid material from the anus. However, most carps died eventually of intestinal obstruction. Other significant necropsy fadings included cyst formation of various size in the intestinal mucosa, ascites, anemic condition through internal organs and muscular tissues, hyperemia and dilation of intestines with decreased tension, thinness and fragility, and full contents of semi-fluid or yellowish white mucoid material in the intestinal canals. Based on the morphological characteristics of the spores found in the cysts, parasitic location in the intestines, macro- and microscopic findings of the lesions, the parasites were identised as Thelohanellus kitauei Egusa os Nakajima, 1981. Although monthly changes of water temperature were distinct, the extrusion rates of the polar filaments of the spores stayed constant throughout the year with an exception of a lower rate in July, The lesions initiated from mucosa and submucosa in early July became large swellings and then complete mature (orms following the peracute course. From late August the upper cysts were gradually opened and most of the spores were dispersed from anus into the surrounding water through December but only a few lasted until next April. The cysts were completely recovered until next September. Comparing the incidence and prevalence of the disease by year tremendous infection and death rates were checked in the first prevalent year, 1988, but the rates were significantly decreased in the second year, and showed an almost normal status in the third year, 1990. As the above summarized results showed, the disease entity might come to an end in three years after the first prevalent year, however, the spores must be strictly prevented because they could be infective in the water for one year.

• Economic and Environmental Geology
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• v.55 no.5
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• pp.429-438
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• 2022

This study evaluated the effect of the degree of weathering on the particle size distribution and the amount of fine particles generated in the aggregate production process during the crushing of igneous rock. Rock samples were collected from three areas with differences in strength from the Schmith hammer measurement at the aggregate quarry in Geochang, Gyeongsangbuk-do. After crushing with a jaw crusher under the same conditions in laboratory, particle size analysis, mineral analysis, chemical analysis, and weathering index were calculated. The Schmidt hammer measurements were 56, 28, and <10, and the CIA and CIW values of weathering index were also different, so the rock samples were classified into hard rock, soft rock, and weathered rock according to the weathering degree. It shows a smaller particle size distribution toward weathered rocks under the microscope, and the proportion of altered clay minerals such as sericite increased. The composition of feldspar and quartz was high for hard rock, and the ratio of muscovite and kaolinite was low. As a result of the crushing of the jaw crusher, hard rock produced a lot of coarse crushed material (13.2mm), while soft rock and weathered rock produced fine crushed material (4.75mm). The former showed the characteristics of the beta distribution curve, and the latter showed the bimodal distribution curve. The production of fine rock particles (based on 0.71mm of sieve, wt. %) increased to 13%<21%<22% in hard rock, soft rock, and weathered rock, and the greater the degree of weathering, the more fine rock particles were generated. The fine particles are recovered by the operation of the sand unit in the wet aggregate production process. Therefore, in order to minimize the amount of sludge generated in the aggregate production process, it was judged that a study on the optimal operation of cyclones could be necessary.

• Journal of Chest Surgery
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• v.37 no.2
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• pp.119-130
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• 2004

Decrease in cardiac function after open heart surgery is due to an ischemia induced myocardial damage during surgery, and ischemic preconditioning, a condition in which the myocardial damage does not accumulate after repeated episodes of ischemia but protects itself from damage after prolonged ischemia due to myocytes tolerating the ischemia, is known to diminish myocardial damage, which also helps the recovery of myocardium after reperfusion, and decreases incidences of arrythmia. Our study is performed to display the ischemic preconditioning and show the myocardial protective effect by applying cardioplegic solution to the heart removed from rat. Material and Method: Sprague-Dawley male rats were used, They were fixed on a modified isolated working heart model after cannulation. The reperfusion process was according to non-working and working heart methods and the working method was executed for 20 minutes in which the heart rate, aortic pressure, aortic flow and coronary flow were measured and recorded. The control group is the group which the extracted heart was fixed on the isolated working heart model, recovered by reperfusion 60 minutes after infusion and preserved in the cardioplegic solution 20 minutes after the working heart perfusion and aortic cross clamp, The thesis groups were divided into group I, which ischemic hearts that were hypoxia induced were perfused by cardioplegic solution and preserved for 60 minutes; group II, the cardioplegic solution was infused 45 seconds (II-1), 1 minutes (II-2), 3 minutes (II-3), after the ischemia induction, 20 minutes after working heart perfusion and aortic cross clamp; and group III, hearts were executed on working heart perfusion for 20 minutes and aortic cross clamp was performed for 45 seconds (III-1), 1minute (III-2), 3 minutes (III-3), reperfused for 2 minutes to recover the heart, and then aortic cross clamping was repeated for reperfusion, all the groups were compared based on hemodynamic performance after reperfusion of the heart after preservation for 60 minutes. Result: The recovery time until spontaneous heart beat was longer in groups I, II-3, III-2 and III-3 to control group (p<0.01). Group III-1 (p<0.05) had better results in terms of recovery in number of heart rates compared to control group, and recovered better compared to II-1 (p<0.05). The recovery of aortic blood pressure favored group III-1 (p<0.05) and had better outcomes compared with II-1 (p<0.01). Group III-1 also showed best results in terms of cardiac output (p<0.05) and group III-2 was better compared to II-2 (p<0.05). Group I (p<0.01) and II-3 (p<0.05) showed more cardiac edema than control group. Conclusion: When the effects of other organs are dismissed, protecting the heart by infusion of cardioplegic solution after enforcing ischemia for a short period of time before the onset of abnormal heart beats for preconditioning has a better recovery effect in the cardioplegic group with preconditioning compared to the cardioplegic solution itself. we believe that further study is needed to find a more effective method of preconditioning.

• The Korean Journal of Petroleum Geology
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• v.5 no.1_2 s.6
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• pp.48-58
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• 1997

Core samples from the B, E, F, H wells in the Tertiary Pohang Basin were analysed for total organic carbon (TOC) content and subject to Rock-Eval pyrolysis in order to assess petroleum geochemical characteristics of organic matter. Following geochemical screening, we selected samples from each well for the study of bitumen and kerogens such as optical observation, infra-red spectroscopy and biomarker analyses. Sediments of the Tertiary Yonil Group contain total organic carbon ranging from $0.55{\%} to 3.74{\%}$ with S1+S2 values higher than 2mgHC/g Rock in B, E and F wells, which indicates fair hydrocarbon generation potential. Most organic matter in the B, E, F wells is compared to type II based on the Rock-Eval pyrolysis, infra-red spectroscopy and optical observation. However, organic matter in the H well is compared to type III because the well is located at the margin of the basin where the preservation of terrestrial material is dominant. Geochemical analyses show that organic matter in the Yonil Group is thermally immature although thermal maturity slightly increases with depth. Maturity levels of the extracted kerogens are similar to those of bulk samples ($Tmax<435^{\circ}C$. Petroleum geochemical charateristics of the sediments in the Tertairy Yonil Group is fair in terms of the organic richness and hydrocarbon genetic potential, but organic matter is thermally immature due to the shallow burial depth. Optical observation of the kerogens and biomarker analysis show that organic matter in the Yonil Group is both marine and terrestrial origin, although it was deposited in marine environment. Pristane/phytane ratio suggests rather anoxic depositional environment. Transitional characteristics of organic matter indicate that the marine Yonil Group was deposited near the terrestrial environments. Input of terrestrial organic matter is more prevalent in the samples recovered from the lowermost horizon in the wells due to the terrestrial environment at the time of basin formation.