• Clean Technology
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• v.30 no.1
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• pp.1-12
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• 2024

Nanoplastics (NP) exhibit distinct material properties compared to microplastics (MP), necessitating their separate recognition. Review of research outcomes and policy documents on NP reveals that most policy frameworks predominantly define MPs as solid synthetic polymer materials measuring 5 mm or less, but do not distinguish them from NP. However, recent revisions in regulations by the EU classify NPs as particles that range in size from 1 to 1,000 nm, as confirmed by some academic studies. Research on NPs often relies on experimental investigations centered around water systems, with a focus on high-concentration experimental conditions using spherical polystyrene-based NPs in behavior and impact studies. Notably, the environmental behavior characteristics of NP show differences in influence depending on the NP type, emphasizing the need for field simulation research. These challenges are mirrored in Korean society, so it is necessary to redefine NP to be distinct from MP in both research and policy. This study aimed to assess the current state of NP management globally and domestically and highlight policy considerations and issues in the existing response to NP. Upon comprehensive review, it becomes apparent that reaching an international agreement on MP faces methodological limitations, which could potentially burden efforts to precisely define NP size. Therefore, referencing the EU's recent regulatory revisions is crucial in domestic policy. Specific adjustments should commence from the MP concept through insights from the domestic industry, guidance from the academic community, and thorough discussions to ensure social acceptance.

• Phonetics and Speech Sciences
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• v.16 no.2
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• pp.29-36
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• 2024

A speech processing model based on a psycholinguistic approach can identify the specific speech processing deficits of children with speech sound disorders (SSDs) through various pathways. In most cases, the cause of the speech problem with SSD children is unknown, so it is important to identify the underlying strengths and weaknesses for individualized intervention. In addition, because the native language deficits can also affect foreign language production, it is necessary to examine speech processing abilities between the two languages. This study is a preliminary study to develop a Korean-English speech processing task system. Speech production task and speech processing task (DT, PRT, NRT) were conducted both in Korean and English on 10 children with SSD and 20 normal children (NSA). As a result, the SSD group showed significantly lower production ability than the NSA group in both languages. As a result of the speech processing task, there was no significant difference in the discrimination task (DT), while there was a significant difference between language types in the phonological representation task (PRT) and between language types and groups in the nonword repetition task (NRT). The results of this study confirmed that children's native language and foreign language processing skills may be different, and that the sub-tasks of speech processing system should be further subdivided.

• Tuberculosis and Respiratory Diseases
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• v.87 no.2
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• pp.155-164
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• 2024

Background: Exercise capacity is associated with lung function decline in chronic obstructive pulmonary disease (COPD) patients, but a discrepancy between exercise capacity and airflow limitation exists. This study aimed to explore factors contributing to this discrepancy in COPD patients. Methods: Data for this prospective study were obtained from the Korean COPD Subgroup Study. The exercise capacity and airflow limitation were assessed using the 6-minute walk distance (6-MWD; m) and forced expiratory volume in 1 second (FEV₁). Participants were divided into four groups: FEV₁ >50%+6-MWD >350, FEV₁ >50%+6-MWD ≤350, FEV₁ ≤50%+6-MWD >350, and FEV₁ ≤50%+6-MWD ≤350 and their clinical characteristics were compared. Results: A total of 883 patients (male:female, 822:61; mean age, 68.3±7.97 years) were enrolled. Among 591 patients with FEV₁ >50%, 242 were in the 6-MWD ≤350 group, and among 292 patients with FEV₁ ≤50%, 185 were in the 6-MWD >350 group. The multiple regression analyses revealed that male sex (odds ratio [OR], 8.779; 95% confidence interval [CI], 1.539 to 50.087; p=0.014), current smoking status (OR, 0.355; 95% CI, 0.178 to 0.709; p=0.003), and hemoglobin levels (OR, 1.332; 95% CI, 1.077 to 1.648; p=0.008) were significantly associated with discrepancies in exercise capacity and airflow limitation in patients with FEV₁ >50%. Meanwhile, in patients with FEV₁ ≤50%, diffusion capacity of carbon monoxide (OR, 0.945; 95% CI, 0.912 to 0.979; p=0.002) was significantly associated with discrepancies between exercise capacity and airflow limitation. Conclusion: The exercise capacity of COPD patients may be influenced by factors other than airflow limitation, so these aspects should be considered when assessing and treating patients.

• Korean Circulation Journal
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• v.52 no.8
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• pp.606-620
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• 2022

Background and Objectives: Protein-losing enteropathy (PLE) is a devastating complication after the Fontan operation. This study aimed to investigate the clinical characteristics, treatment response, and outcomes of Fontan-associated PLE. Methods: We reviewed the medical records of 38 patients with Fontan-associated PLE from 1992 to 2018 in 2 institutions in Korea. Results: PLE occurred in 4.6% of the total 832 patients after the Fontan operation. After a mean period of 7.7 years after Fontan operation, PLE was diagnosed at a mean age of 11.6 years. The mean follow-up period was 8.9 years. The survival rates were 81.6% at 5 years and 76.5% at 10 years. In the multivariate analysis, New York Heart Association Functional classification III or IV (p=0.002), low aortic oxygen saturation (<90%) (p=0.003), and ventricular dysfunction (p=0.032) at the time of PLE diagnosis were found as predictors of mortality. PLE was resolved in 10 of the 38 patients after treatment. Among medical managements, an initial heparin response was associated with survival (p=0.043). Heparin treatment resulted in resolution in 4 patients. We found no evidence on pulmonary vasodilator therapy alone. PLE was also resolved after surgical Fontan fenestration (2/6), aortopulmonary collateral ligation (1/1), and transplantation (1/1). Conclusions: The survival rate of patients with Fontan-associated PLE has improved with the advancement of conservative care. Although there is no definitive method, some treatments led to the resolution of PLE in one-fourth of the patients. Further investigations are needed to develop the best prevention and therapeutic strategies for PLE.

• The Journal of KAIRB
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• v.6 no.2
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• pp.48-55
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• 2024

Purpose: The purpose of this study is to introduce the Institutional Review Board (IRB) member-based internal audit method performed at A University Hospital, a secondary medical institution, and to identify the differences in audit results according to the characteristics of each auditor and the factors affecting the internal audit results. Furthermore, we will find out what needs to be improved in the internal audits to achieve Quality assurance (QA) objectives for human subject research conducted in medical institutions. Methods: The auditors were divided into group A (IRB member belonging to institution A) and group B (clinical trial QA administrator belonging to other institutions) and independently inspected the 2 studies using the same internal audit checklist (consisting of 11 domains, 130 items), and the differences in the internal inspection checklists written by each auditor were compared and analyzed. Results: In the case of audit for the study 1, the number of missing checklists is 1 for group A and 0 for group B, and the number of the matters to be pointed out is 1 for group A and 12 for group B. In the case of audit for the study 2, the number of missing checklists is 2 for both A and B, and the number of points is 5 for A and 4 for B. The differences in the internal audit results written by each auditor that the authors verified are summarized as follows. First, there were more comments from group B auditor than from group A auditor. Second, the results may vary because each auditor has different criteria for evaluating the appropriateness of an item. Third, there are cases where the questions on the checklist are vague or the definition is not clear, so they have the same opinion but check it with different answers. Fourth, if the auditors make a mistake when filling out the checklist, it causes to led to different the results. Conclusion: We propose the following items that should be improved in order to conduct consistent and efficient internal audits. First, it is necessary to test the tool in order to carry out reliable and consistent internal audits. Second, it is necessary to complete specialized training related to internal audit before conducting internal audit. Third, before notifying the audit results, it is necessary to have a procedure or a final review system to check whether the audit contents are appropriate. Fourth, Institutional support is needed to recruit specialized personnel for internal audits.

• Korean Journal of Organic Agriculture
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• v.32 no.2
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• pp.233-245
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• 2024

In a field study, we investigated the consequences associated with the irrigation of red pepper with water contaminated by three types of veterinary antibiotics (amoxicillin, oxytetracycline, and chlortetracycline) on the soil residue, the absorption-translocation, and crop yields. As a result of evaluating the residue of veterinary antibiotics in pepper cultivation soil treated with veterinary antibiotics a total of 7 times from June 7 to August 26, 2023, the three antibiotics were not detected at the background level, but in the group treated with 10-fold and 50-fold of the background level was detected at a level of 2-10 ㎍/kg. For the leaf (stem) and fruit of red pepper, all three types of veterinary antibiotics were found to be below the detection limit at all treatments. However, trace levels were detected in red pepper roots. If veterinary antibiotics are unintentionally introduced into agricultural soil in the short term, the soil environment and crop safety will not be a problem. However, long-term introduction of veterinary antibiotics in agricultural soil may have negative effects by affecting soil microbial diversity and antibiotic resistance problems, so continuous monitoring and risk assessment are deemed necessary.

• Korean Journal of Plant Resources
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• v.37 no.4
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• pp.431-438
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• 2024

Hops enhance beer flavor and bitterness, acting as a preservative. In recent years, the booming trend of craft beer has prompted the introduction of foreign hop varieties for cultivation and production in South Korea. This study focuses on developing efficient in vitro culture condition of the hop (Humulus lupulus L.) variety 'Cascade' for treatments of plant growth regulators, i.e. IAA and Cytokinin. Using Auxin IAA and Cytokinin 2iP, Zeatin, BAP, and TDZ on MS medium as plant growth regulators, the experiment involved removing three nodes from the shoot apex. In vitro hop culture showed the highest shoot proliferation rate when only IAA was added, with approximately 21% higher compared to the combination with Cytokinin. Notably, IAA 0.1 mg/L + BAP 1 mg/L resulted in a superior shoot proliferation rate of around 91%. IAA 0.1 mg/L + BAP 1 mg/L was advantageous for shoot elongation. Callus induction occurred with TDZ, while control or IAA-only conditions exhibited shoot and root growth. Cytokinin addition led to callus formation and increased weight. Assessing survival and soil adaptation during in vitro hop seedling acclimatization involved maintaining near 100% humidity initially, gradually reducing it over three weeks. When transferred outdoors, 9 out of 10 seedlings acclimated successfully, confirming a 90% acclimatization rate.

• Journal of Wind Energy
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• v.13 no.4
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• pp.26-41
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• 2022

Three similarities (i.e., geometrical similarity, kinematic similarity and dynamic similarity) between a prototype and model must be satisfied to perform an experiment for a floating offshore wind turbine (FOWT). For dynamic similarity, most of the model tests in ocean engineering basins are performed based on the Froude number, so the scale effect for the wind turbine of an FOWT occurs by different Reynolds numbers between the prototype and model. In this study, various model test techniques for overcoming the scale effect of the wind turbine part of the FOWT are investigated. Firstly, model test techniques using simple approaches are reviewed, and the advantages and disadvantages of the simple approaches are summarized. Secondly, the model test techniques in recent projects that apply improved approaches are introduced including advantages and disadvantages. Finally, new approaches applying digitalization are reviewed, and the characteristics of the new approaches are introduced.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.3
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• pp.289-299
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• 2024

Chrysanthemum lucidum (C. lucidum), a perennial herb in the Asteraceae family, is an endemic species found only on Ulleung island in Gyeongsangbuk-do, South Korea. Previous studies have reported that the extract of C. lucidum exhibits excellent antioxidant activity due to its high polyphenol and flavonoid content. However, the anti-aging effects of C. lucidum extract, such as wrinkle improvement and cell regeneration, are not well known, and there has been no research on the activity of C. lucidum-derived extracellular vesicles (ClDEVs). Therefore, this study aimed to verify the anti-aging effects of ClDEVs through in vitro and clinical analyses. In cell experiments, ClDEVs promoted cell regeneration, increased the expression of COL1A1, a gene involved in collagen synthesis, and enhanced the expression of FLG and LOR, a biomarker related to skin barrier improvement. Additionally, ClDEVs suppressed the expression of aging-related biomarkers, such as the CDKN2A (encodes p16) and TP53 (encodes p53) genes, in cells induced to age. In a human clinical trial, after using a cosmetic product containing ClDEVs for 4 weeks, significant improvement in wrinkles around the eyes and nasolabial folds was observed. In conclusion, ClDEVs have demonstrated high potential as a bio-cosmetic ingredient for wrinkle improvement and anti-aging.

• Journal of Sensor Science and Technology
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• v.33 no.5
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• pp.318-325
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• 2024

In this study, we fabricated TiO₂-decorated SnO₂ nanorods (TSNRs) via glancing-angle deposition to achieve highly sensitive and selective CH₃COCH₃ detection. The gas-sensing properties of the TSNRs were systematically investigated, and the optimal sensing performance was achieved at 350℃ by 2-nm-thick TSNRs. When the sensors were exposed to 50 ppm of various gases (CH₃COCH₃, C₂H₅OH, C₅H₈, CH₄, and CO), the 2-nm-thick TSNRs demonstrated a 4.6-fold increase in response (R_a/R_g-1=134) to CH₃COCH₃ compared with bare SnO₂ nanorods (R_a/R_g-1=29.5) and exhibited excellent selectivity. In a high-humid environment (relative humidity = 80%), the 2-nm-thick TSNRs indicated a low theoretical detection limit of ≈5.31 ppb for CH₃COCH₃. These results suggest the significant potential of the proposed sensor for use in Internet-of-Things applications, particularly under extreme environmental conditions.