• Journal of Korean Society of Forest Science
• /
• v.113 no.2
• /
• pp.143-152
• /
• 2024

This study was conducted to evaluate the growth and nutrient dynamics in response to fertilization of four tree species (LT: Liriodendron tulipifera L.; PY: Prunus yedoensis Matsumura; QA: Quercus acutissima Ca rruth; a nd PT: Pinus thunbergii Parl.) planted in a fire-disturbed urban forest in Bongdaesan (Mt.), Ulsan Metropolitan Area, South Korea. The trees were planted in 2009, and compound fertilizers (N₆P₄K₁) were applied in April 2013 and March 2014. Tree growth, soil, and foliage nutrients were examined from March 2013 to October 2016. The regression coefficients for the increment of the diameter at breast height (DBH) significantly differed between the fertilized and unfertilized plots, suggesting the significant effects of fertilization. By contrast, fertilization did not affect the coefficients for height increments. Regarding soil nutrient contents, organic carbon and total nitrogen concentrations were lower in the fertilized plots than in the unfertilized plots, whereas available phosphorus, exchangeable calcium, and magnesium concentrations were higher in the fertilized plots than in the unfertilized plots. In foliage, nitrogen and phosphorus concentrations were higher in the fertilized plots than in the unfertilized plots, whereas potassium, calcium, and magnesium concentrations were not affected by fertilization. Nutrient concentration of foliage among the tree species were higher in LT and PY than in QA and PT. These results suggest that fertilizers may be used to enhance soil fertility and the growth and nutrient status of tree species planted in a fire-disturbed urban forest.

• The Journal of the Acoustical Society of Korea
• /
• v.29 no.5
• /
• pp.314-324
• /
• 2010

In waveguide structures, waves may be partially reflected by local non-uniformities. The effects of local non-uniformities has been previously investigated by means of a combined spectral element and finite element (SE/FE) method at relatively low frequencies. However, since the SE is formulated based on a beam theory, the SE/FE method is not appropriated for analysis at higher frequencies where complex deformation of the waveguide occurs. So it is necessary to extend this approach for high frequencies. For the wave propagation at higher frequencies, a combined spectral super element and finite element (SSE/FE) method is introduced in this paper. As an example of the application of this method, wave reflection and transmission due to a local defect in a rail are simulated at frequencies between 20kHz and 30kHz. Also numerical errors are evaluated by means of the conservation of the incident power.

• The Journal of the Acoustical Society of Korea
• /
• v.28 no.6
• /
• pp.572-577
• /
• 2009

Large corpus-based concatenating Text-to-Speech (TTS) systems can generate natural synthetic speech without additional signal processing. To prune the redundant speech segments in a large speech segment DB, we can utilize a decision-tree based triphone clustering algorithm widely used in speech recognition area. But, the conventional methods have problems in representing the acoustic transitional characteristics of the phones and in applying context questions with hierarchic priority. In this paper, we propose a new clustering algorithm to downsize the speech DB. Firstly, three 13th order MFCC vectors from first, medial, and final frame of a phone are combined into a 39 dimensional vector to represent the transitional characteristics of a phone. And then the hierarchically grouped three question sets are used to construct the triphone trees. For the performance test, we used DTW algorithm to calculate the acoustic similarity between the target triphone and the triphone from the tree search result. Experimental results show that the proposed method can reduce the size of speech DB by 23% and select better phones with higher acoustic similarity. Therefore the proposed method can be applied to make a small sized TTS.

• Journal of Life Science
• /
• v.34 no.5
• /
• pp.287-295
• /
• 2024

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related mortality worldwide, necessitating novel therapeutic strategies. The chemotherapeutic agents used to treat HCC patients are toxic and have serious side effects. Therefore, we investigated the efficacy of anticancer drugs that reduce side effects by targeting tumor cells without causing cytotoxicity in healthy hepatocytes. Berberine, an isoquinoline alkaloid derived from plant compounds, has emerged as a potential candidate for cancer treatment due to its diverse pharmacological properties. The effect of berberine on HepG2 cell viability was determined using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay. HepG2 cell proliferation was determined through a colony-forming assay. The effects of berberine on HepG2 cell migration were evaluated using a wound-healing assay. Berberine inhibited the proliferation of HepG2 cells, as well as colony formation and migration. Berberine treatment increased the expression of autophagy-related genes and proteins, including Beclin-1 and LC3-II, and elevated the activities and mRNA expression of Caspase-9 and Caspase-3. Additionally, in experiments utilizing the Cell-Derived Xenograft animal model, berberine treatment reduced tumor size and weight in a concentration-dependent manner. These results demonstrate the potential of berberine as a versatile anticancer agent with efficacy in both cellular and animal models of hepatocellular carcinoma. The findings herein shed light on berberine's efficacy against HCC, presenting opportunities for targeted and personalized therapeutic interventions.

• Journal of Navigation and Port Research
• /
• v.47 no.6
• /
• pp.350-357
• /
• 2023

Marine accidents frequently occur due to the unreasonable operation of ships excluded from ship departure control during marine special weather warnings within smooth water areas. Coastal wave buoys installed in smooth water areas are major reference indicators for ship departure control and can be seen as being directly connected to the safety of ships navigating smooth water areas and the coast. In this study, the location appropriateness of currently operating coastal wave buoys and additional installation in the smooth water areas were assessed by analyzing coastal marine accidents over the past 30 years (1991-2020), the main wind direction and wind speed of each major trading port, and the GICOMS ship track data in 2018. The study results showed that an additional coastal wave buoy should be installed at each of the major trading ports(Inchon Port, Pohang Port, Ulsan Port, and Busan Port) and that the location of the coastal wave buoy needs to be moved in the case of Busan Port. Based on various data analysis in this study, the suggestion for an additional installation and movement of the coastal wave buoy presented in this study is expected to contribute to improving the reliability of ship departure control and resolving safety blind spots.

• Quality Improvement in Health Care
• /
• v.30 no.1
• /
• pp.33-43
• /
• 2024

Purpose:The acute hospital accreditation program launched in South Korea has shown positive effects on safety culture and quality of care. However, relative weights have not yet been investigated for accreditation criteria with a hierarchical structure. This study aimed to derive the relative weights of acute-care hospital accreditation criteria. Methods: We conducted an online survey using the analytic hierarchy process (AHP) technique to assess the validity, importance, and urgency of acute hospital accreditation criteria. The AHP online survey link was distributed in November 2022 after obtaining informed consent from 10 experts in hospital accreditation. Results: 'Basic value system' ranked highest, while 'patient care system' ranked second in terms of validity, importance, and urgency. 'Performance management system' had the lowest validity and urgency, while 'organizational management system' carried the lowest importance. Within the 'patient care system' domain, 'surgery and anesthesia sedation management' scored highest in validity and importance, and 'patient care' scored highest in urgency. 'Care delivery system and evaluation' received the lowest scores for all three aspects. In the 'organizational management system' domain, infection control ranked highest in terms of validity, importance, and urgency. The lowest validity was observed for 'management and organizational operation' and the lowest importance and urgency were noted for 'human resource management'. Conclusion: The weights for validity, importance, and urgency, as shown in each domain and chapter, and the number of measurable elements included, are largely inconsistent. This study will contribute to the development of the structure and scientific improvement of accreditation standards.

• Journal of the Korean Society of Radiology
• /
• v.83 no.3
• /
• pp.658-668
• /
• 2022

Purpose To evaluate the effectiveness of the transradial artery approach (TRA) for treating malfunctioning arteriovenous fistulas (AVFs) in patients on hemodialysis. Materials and Methods A retrospective analysis was conducted in this single-center study of TRA endovascular procedures in 73 patients (43 male and 30 female; mean age of 67.4 years (range, 42-92 years) with malfunctioning AVFs, between January 2008 and April 2019. Patients' baseline and lesion characteristics, technical and clinical success, and complications were evaluated, and functional patency was analyzed using the Kaplan-Meier method. Results Radial artery approaches were successful in all patients. Angioplasty performed using the TRA achieved technical and clinical success rates of 98.6%(72/73) and 91.7%(67/73), respectively. The median primary patency time was 18.8 ± 15.9 months. The primary functional patency rates at 3, 6, and 12 months were 82.1%, 68.6%, and 63.9%, respectively. There were no major complications or adverse events, such as hand ischemia, related to the radial artery approach. Conclusion In selected cases, the TRA can be used complementary to the transvenous approach to treat malfunctioning AVFs.

• Journal of the Korean Society of Radiology
• /
• v.83 no.2
• /
• pp.265-283
• /
• 2022

To develop Korean coronavirus disease (COVID-19) chest imaging justification guidelines, eight key questions were selected and the following recommendations were made with the evidence-based clinical imaging guideline adaptation methodology. It is appropriate not to use chest imaging tests (chest radiograph or CT) for the diagnosis of COVID-19 in asymptomatic patients. If reverse transcription-polymerase chain reaction testing is not available or if results are delayed or are initially negative in the presence of symptoms suggestive of COVID-19, chest imaging tests may be considered. In addition to clinical evaluations and laboratory tests, chest imaging may be contemplated to determine hospital admission for asymptomatic or mildly symptomatic un-hospitalized patients with confirmed COVID-19. In hospitalized patients with confirmed COVID-19, chest imaging may be advised to determine or modify treatment alternatives. CT angiography may be considered if hemoptysis or pulmonary embolism is clinically suspected in a patient with confirmed COVID-19. For COVID-19 patients with improved symptoms, chest imaging is not recommended to make decisions regarding hospital discharge. For patients with functional impairment after recovery from COVID-19, chest imaging may be considered to distinguish a potentially treatable disease.

• Journal of the Korean Society of Radiology
• /
• v.83 no.5
• /
• pp.1032-1045
• /
• 2022

Peripheral arterial disease (PAD) is common in elderly patients. Lower-extremity CT angiography (LE-CTA) can be useful for detecting PAD and planning its treatment. PAD can also be accurately evaluated on reconstructed monoenergetic images (MEIs) from low kiloelectron volt (keV) to high keV images using dual-energy CT. Low keV images generally provide higher contrast than high keV images but also feature more severe image noise. The noise-reduced virtual MEI reconstruction algorithm, called the Mono+ technique, was recently introduced to overcome such image noise. Therefore, this pictorial review aimed to present the imaging findings of PAD on LE-CTA and compare low and high keV images with those subjected to the Mono+ technique. We found that, in many cases, the overall and segmental image qualities were better and metal artifacts and venous contamination were decreased in the high keV images.

• Journal of the Korean Society of Radiology
• /
• v.81 no.2
• /
• pp.272-289
• /
• 2020

Current advances in CT techniques allow thorough evaluation of the beating heart. The strengths of cardiac CT relative to echocardiography and magnetic resonance imaging are its high availability in most institutions, rapid production of high-quality images, and outstanding delineation of the anatomy. For many normal variants and pathologic conditions, such as thrombi, masses, and congenital abnormalities of the left atrium, CT findings are sufficient to make a presumptive diagnosis. Assessments of the left atrium and left atrial appendage are particularly important for the management of atrial fibrillation, as various catheter-based procedures are aimed at the mechanical and electrical isolation of these structures. CT offers information crucial to a successful catheter-based procedure or surgery. Therefore, a comprehensive review of the geometry (shape, size, and relative position), along with various CT imaging features of pathologic states, should be provided in radiology reports to be of clinical value.