• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.6
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• pp.256-268
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• 2016

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2015. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering were carried out in the areas of flow, heat and mass transfer, cooling and heating, and air-conditioning, the renewable energy system and the flow inside building rooms. Research issues dealing with air-conditioning machines and fire and exhausting smoke were reduced. CFD seems to be spreading to more research areas. (2) Research works on heat transfer area were carried out in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the economic analysis of GHG emission, micro channel heat exchanger, effect of rib angle on thermal performance, the airside performance of fin-and-tube heat exchangers, theoretical analysis of a rotary heat exchanger, heat exchanger in a cryogenic environment, the performance of a cross-flow-type, indirect evaporative cooler made of paper/plastic film. In the area of pool boiling and condensing, the bubble jet loop heat pipe was studied. In the area of industrial heat exchangers, researches were performed on fin-tube heat exchanger, KSTAR PFC and vacuum vessel at baking phase, the performance of small-sized dehumidification rotor, design of gas-injection port of an asymmetric scroll compressor, effect of slot discharge-angle change on exhaust efficiency of range hood system with air curtain. (3) In the field of refrigeration, various studies were carried in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, a cold-climate heat pump system, $CO_2$ cascade systems, ejector cycles and a PCM-based continuous heating system were investigated. In the alternative refrigeration/energy system category, a polymer adsorption heat pump, an alcohol absorption heat pump and a desiccant-based hybrid refrigeration system were investigated. In the system control category, turbo-refrigerator capacity controls and an absorption chiller fault diagnostics were investigated. (4) In building mechanical system research fields, eighteen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the user and location awareness technology applied dimming lighting control system, the lighting performance evaluation for light-shelves, the improvement evaluation of air quality through analysis of ventilation efficiency and the evaluation of airtightness of sliding and LS window systems. The subjects of building energy were worked on the energy saving estimation of existing buildings, the developing model to predict heating energy usage in domestic city area and the performance evaluation of cooling applied with economizer control. The studies were also performed related to the experimental measurement of weight variation and thermal conductivity in polyurethane foam, the development of flame spread prevention system for sandwich panels, the utilization of heat from waste-incineration facility in large-scale horticultural facilities.

• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.52-62
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• 2023

This study focused on determining the specific causes and prevention methods of mass fish deaths occurred in five reservoirs (Gagugi, Neupgokgi, Danggokgi, Sagokji, and Hangokji) in Andong-si. For this purpose, a survey of agricultural land and livestock in the upper part of the reservoirs and analysis of water quality in the reservoir irrespective of whether it rains or not were conducted. We attempted to examine the changes in dissolved oxygen (DO) in the surface and bottom layers of reservoirs and changes in DO depending on the amount of livestock compost and time. Based on the above investigations, treatment plans were established to efficiently control the inflow of contaminated water into reservoirs. The rainfall and farmland areas in the upper part of the reservoir were investigated using Google and aviation data provided by the Ministry of Land, Infrastructure, and Transport. The current status of livestock farms distributed around the reservoirs was also examined because compost from these farms can flow into the reservoir when it rains. Various water quality parameters, such as phosphate phosphorus (PO₄-P) and ammonium nitrogen (NH₃-N), were analyzed and compared for each reservoir during the rainy season. Changes in the DO concentration and electrical conductivity (EC) were also observed at the inlet of the reservoir during raining using an automated instrument. In addition, DO was measured until the concentration reached 0 ppm in 10 min by adding livestock compost at various concentrations (0.05%, 0.1%, 0.3%, and 0.5% by wt.), where the concentration of the livestock compost represents the relative weight of rainwater. The DO concentration in the surface layer of reservoirs was 3.7 to 5.3 ppm, which is sufficient for fish survival. However, the fish could not survive at the bottom layer with DO concentration of 0.0-2.1 ppm. When the livestock compost was 0.3%, DO required 10-19 h to reach 0 ppm. Considering these results, it was confirmed that the DO in the bottom layer of the reservoir could easily change to an anaerobic state within 24 h when the livestock compost in the rainwater exceeds 0.3%. The results show that the direct cause of fish mortality is the inflow of excessive livestock compost into reservoirs during the first rainfall in spring. All the surveyed reservoirs had relatively good topographical features for the inflow of compost generated from livestock farms. This keeps the bottom layer of the reservoir free of oxygen. Therefore, to prevent fish death due to insufficient DO in the reservoir, measures should be undertaken to limit the amount of livestock compost flowing into the reservoir within 0.3%, which has been experimentally determined. As a basic countermeasure, minerals such as limestone, dolomite, and magnesia containing calcium and magnesium should be added to the compost of livestock farms around the reservoir. These minerals have excellent pollutant removal capabilities when sprayed onto the compost. In addition, measures should be taken to prevent fish death according to the characteristics of each reservoir.

• Tuberculosis and Respiratory Diseases
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• v.58 no.3
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• pp.248-256
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• 2005

Background : Nontuberculous mycobacterial (NTM) infections are increasingly being recognized as a cause of chronic pulmonary disease. This study describes the prevalence of NTM species from clinical specimens and the clinical characteristics of NTM pulmonary disease. Material and Methods : The NTM isolated from March 2003 to December 2003 at the Kosin Medical Center were identified using an oligonucleotide chip containing the internal transcribed space (ITS) sequence. The medical records of the patients with the NTM isolates, who fulfilled the 1997 ATS diagnostic criteria for NTM pulmonary disease, were analyzed, retrospectively. Results : Twenty four species (24.2%) of NTM were isolated from 99 cultured AFB specimens. M. avium complex (MAC) (13 isolates), M. szulgai (3), M. kansasii (2), M. malmoense (2), M. abscessus (1), M. chelonae (1), M. scrofulaceum (1), and unclassified (1). Of the 23 patients with isolated NTM, 11 patients were found to be compatible with a NTM pulmonary infection according to the ATS criteria; MAC was found in 6 cases (54.5%), M. szulgai in 2 cases (18.2%), and M. abscessus, M. szulgai, M. kansasii and M. malmoense in 1 case each (9.1%). Ten patients (91%) were male and the median age at diagnosis was 61 years. In the pre-existing diseases, malignant disease was found in 6 cases including 5 patients with lung cancer, and history of old pulmonary tuberculosis was identified in 4 cases. The radiological patterns showed lung destruction lung in 3 cases, a cavitary mass in 3 cases, a nodular pattern in 2 cases, and reticulonodular, consolidation and a bronchiectasis pattern were in 1 case each. Conclusion : Various types of NTM pulmonary diseases were found in a tertiary hospital at Busan, Korea. The NTM pulmonary diseases were caused by MAC, M. szugai, M. kansasii, M. malmoense, M. abscessus, M. chelonae, and M. scrofulaceum in the order of frequency.

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.654-669
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• 2021

Purpose To evaluate the accuracy of MRI in predicting the pathological complete response (pCR) and the residual tumor size of breast cancer after neoadjucant chemotherapy (NAC), and to determine the factors affecting the accuarcy. Materials and Methods Eighty-eight breast cancer patients who underwent surgery after NAC at our center between 2010 and 2017 were included in this study. pCR was defined as the absence of invasive cancer on pathological evaluation. The maximum diameter of the residual tumor on post-NAC MRI was compared with the tumor size of the surgical specimen measured pathologically. Statistical analysis was performed to elucidate the factors affecting pCR and the residual tumor size-discrepancy between the MRI and the pathological measurements. Results The pCR rate was 10%. The diagnostic accuracy of MRI and the area under the curve for predicting pCR were 90.91% and 0.8017, respectively. The residual tumor sizes obtained using MRI and pathological measurements showed a strong correlation (r = 0.9, p < 0.001), especially in patients with a single mass lesion (p = 0.047). The size discrepancy between MRI and the pathological measurements was significantly greater in patients with the luminal type (p = 0.023) and multifocal tumors/non-mass enhancement on pre-NAC MRI (p = 0.047). Conclusion MRI is an accurate tool for evaluating pCR and residual tumor size in breast cancer patients who receive NAC. Tumor subtype and initial MRI features affect the accuracy of MRI.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.422-431
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• 2019

Severe droughts in spring have occurred frequently in Korea in recent years, exerting a critical impact on corn yield. Therefore, it is necessary to find physiological and/or molecular indicators of the response to drought stress in maize plants. In this study, we investigated the effects of water-deficit stress on two Korean elite F₁ maize hybrids, Ilmichal and Gwangpyeongok, by withholding water for 10 days at tassel initiation. The water deficit drastically reduced the relative leaf water content, leaf number, leaf area, and stem length, leading to dry matter reduction. Moreover, it reduced the SPAD values and stomatal conductance of leaves in drought-stressed plants of both hybrids. Importantly, the number of leaves and SPAD value were non-destructive and easy to investigate in response to water-deficit stress, suggesting that they may be useful indicators for screening drought-tolerant genetic resources. We detected more than 100 spots that were differentially accumulated under drought stress. Of these spots, a total of 21 protein spots (≥1.5-fold) from drought-exposed maize leaves were successfully analyzed by MALDI-TOF-TOF mass spectrometry. Functional annotation using Gene Ontology analysis revealed that most of the identified proteins were involved in carbohydrate metabolism, stress response fatty acid catabolism, photosynthesis, energy metabolism, and transport. The protein expression levels were increased in both Ilmichal and Gwangpyeongok, except for triosephosphate isomerase, fructose-bisphosphate aldolase, and an uncharacterized protein. The lactoylglutathione lyase delta (3,5)-delta (2,4)-dienoyl-CoA isomerase was overexpressed in Gwangpyeongok only. The results obtained from this study suggest that the drought-specific genes may be useful as molecular markers for screening drought-tolerant maize genotypes.

• Journal of Life Science
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• v.25 no.1
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• pp.53-61
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• 2015

In this study, we tried to separate the photosensitizer that induces apoptosis of leukemia cells (U937) from perilla leaves. Perilla leaves (Perilla frutescens Britt var. japonica Hara) are a popular vegetable in Korea, being rich in vitamins (A and E), GABA, and minerals. Dried perilla leaves were extracted with methanol to separate the photosensitizer by various chromatographic techniques. The structure of the isolated compound (PL9443) was identified by 1D-NMR, 2D-NMR, and FAB-mass spectroscopy. Absorbance of the UV-Vis spectrum was highest at 410 nm and was confirmed by the 330, 410, and 668 nm. PL9443 compound was determined to be pheophorbide, an ethyl ester having a molecular weight of 620. It was identified as a derivative compound of pheophorbide structure when magnesium comes away from a porphyrin ring. Observation of morphological changes in U937 cells following cell death induced by treated PL9443 compound revealed representative phenomena of apoptosis only in light irradiation conditions (apoptotic body, vesicle formation). Results from examining the cytotoxicity of PL9443 substance against U937 cells showed that inhibition rates of the cell growth were 99.9% with the concentration of 0.32 nM PL9443. Also, the caspase-3/7 activity was 99% against U937 cells with the concentration of 0.08 nM of PL9443 substance. The result of the electrophoresis was that a DNA ladder was formed by the PL9443. The PL9443 compound is a promising lead compound as a photosensitizer for photodynamic therapy of cancer.

• Journal of the Korean Orthopaedic Association
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• v.56 no.6
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• pp.498-503
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• 2021

Purpose: The aim of this study were to find ideal entry point of straight antegrade humeral intramedullary nail (SAHN) for the treatment of proximal humerus fracture in Korean and to analyze anatomical conformity using computed tomography. Materials and Methods: From May 2014 to October 2016, the study was conducted retrospectively on 74 Korean patients who had taken computed tomography on both normal and affected shoulder joint as result of shoulder injury. The mean age of the patients was 64.5 years (range, 22-95 years). Radiologic evaluation was done using multiplanar reconstruction technique of the computer tomography on normal proximal humerus. We located ideal entry point of SAHN as the point where humerus intramedullary center axis and humeral head meet. Distance between the entry point and local anatomical landmark was measured. We defined the critical distance as the distance between entry point and the most medial point of the supraspinatus attachment site. For adequate fixation and avoidance of injury to rotator cuff, critical distance should be over 8 mm according to Euler, and we defined the critical type when it is less than 8 mm. Critical distance, sex, age, height, body weight, body mass index was evaluated for the statistical significance. Results: The ideal entry point was as follows: the mean anteroposterior distance, the sagittal distance to the lateral margin of bicipital groove, was 11.5 mm and the mean mediolateral distance, the coronal distance to the lateral margin of grater tuberosity, was 20.5 mm. The mean critical distance, distance from the entry point to the just medial to insertion of the supraspinatus tendon, was 8.0 mm. Critical type with critical distance less than 8 mm was found in 41 in 74 patients (55.4%). Conclusion: The ideal entry point of SAHN in Korean was located on 11.5 mm posteriorly from the lateral margin of bicipital groove and 20.5 mm medially from lateral margin of greater tuberosity. More than half of the cases were critical type. Since critical type can possibly cause rotate cuff injury during nail insertion on entry point, surgeon should consider anatomical variance before choosing surgical option.

• Journal of Yeungnam Medical Science
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• v.9 no.1
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• pp.29-43
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• 1992

A case-control study was conducted to investigate the association between the risk of cancer and selenium concentration in blood and toenails. Seventy three patients and two hundreds eighty three controls were, selected at the Yeungnam University Hospital between May and September in 1991. The selected cases were patients who had been hospitalized for stomach or colon cancer at the Depertment of General Surgery. The controls were people who visited to check physical examination at the Automated Mediscreening Center. The selenium concentration in whole blood and toenails were measured by atomic absorption spectrophotometer equipped with graphite furnace atomizer. The following information was ascertained for all cancer patients and controls : sex, age, body mass index, blood pressure, total serum cholesterol, and history of smoking and drinking. The mean selenium concentration in blood and toenail for all cancer patients were $143.6{\pm}10.8{\mu}g/l$ and $1.04{\pm}0.62{\mu}g/g$ and for the controls, $167.0{\pm}14.5{\mu}g/l$ and $1.15{\pm}0.55{\mu}g/g$, respectively. The difference in blood and toenail selenium concentrations of the two cancer sites was not statistically significant. Metastasis did not influence the concentration of selenium in blood and toenails. In the multiple logistic regression analysis, the blood selenium concentration($_aOR$: 0.888, 95% CI : 0.860-0.918), age, BMI and total serum cholesterol were significant variables for risk of cancer, but the selelenium concentration in toenail was not shown to be a significant variable in this regression analysis. The coefficient for blood selenium concentration adjusted for age, sex, diastolic blood pressure, total serum cholesterol, body mass index and smoking was -0.1184(p<0.01). These findings suggest that low selenium concentration is associated with gastrointestinal cancers. Further epidemiologic studies including important variables such as other antioxidant micronutrients will be necessary.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.369-376
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• 2003

This experiment was conducted to investigate the influence of different levels of metabolizable energy (ME) and crude protein (CP) on post-molt performance and egg quality of spent laying hens. Four hundred and thirty two, ISA Brown hens at sixty six weeks of age after molt induction were fed six experimental diets containing three ME (2,750, 2,800, 2,850 kcal/kg) with two CP (15, 17%) levels in a factorial design. The influence of ME and CP were evaluated on egg production, egg weight and feed intake throughout 24 weeks of production. Egg mass and feed conversion ratio (FCR) were measured during the experimental period. Haugh unit, yolk color and eggshell breaking strength were measured at 5%, 50%, peak, post peak and end stage of egg production. The hens fed 2800 kcal/kg diet along with 15% CP recorded the highest outcome of egg production (P<0.05). The egg weight has been shown to increase with hens receiving 2,800 kcal/kg ME. Daily egg mass tended to increase in hens fed with 15% CP and 2,800 kcal/kg ME. Feed intake decreased significantly with the level of ME and CP in the diet increased (P<0.05). Yolk color was improved significantly in eggs laid by the hens receiving 17% CP than 15% diet. It also tended to be higher in 17% CP with 2,800 or 2,850 kcal/kg ME diet treatments. Egg shell breaking strength increased with hens receiving diets of 15% CP and 2,800 kcal/kg. From this experiment it can be concluded that the ME level of 2,800 kcal/kg coupled with 15% CP could be used to achieve the higher egg production and better eggshell strength in induced molting hens.

• Research in Plant Disease
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• v.8 no.2
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• pp.84-91
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• 2002

Disease forecasting in Korea was first studied in the Department of Fundamental Research, in the Central Agricultural Technology Institute in Suwon in 1947, where the dispersal of air-borne conidia of blast and brown spot pathogens in rice was examined. Disease forecasting system in Korea is operated based on information obtained from 200 main forecasting plots scattered around country (rice 150, economic crops 50) and 1,403 supplementary observational plots (rice 1,050, others 353) maintained by Korean government. Total number of target crops and diseases in both forecasting plots amount to 30 crops and 104 diseases. Disease development in the forecasting plots is examined by two extension agents specialized in disease forecasting, working in the national Agricul-tural Technology Service Center(ATSC) founded in each city and prefecture. The data obtained by the extension agents are transferred to a central organization, Rural Development Administration (RDA) through an internet-web system for analysis in a nation-wide forecasting program, and forwarded far the Central Forecasting Council consisted of 12 members from administration, university, research institution, meteorology station, and mass media to discuss present situation of disease development and subsequent progress. The council issues a forecasting information message, as a result of analysis, that is announced in public via mass media to 245 agencies including ATSC, who informs to local administration, the related agencies and farmers for implementation of disease control activity. However, in future successful performance of plant disease forecasting system is thought to be securing of excellent extension agents specialized in disease forecasting, elevation of their forecasting ability through continuous trainings, and furnishing of prominent forecasting equipments. Researches in plant disease forecasting in Korea have been concentrated on rice blast, where much information is available, but are substan-tially limited in other diseases. Most of the forecasting researches failed to achieve the continuity of researches on specialized topic, ignoring steady improvement towards practical use. Since disease forecasting loses its value without practicality, more efforts are needed to improve the practicality of the forecasting method in both spatial and temporal aspects. Since significance of disease forecasting is directly related to economic profit, further fore-casting researches should be planned and propelled in relation to fungicide spray scheduling or decision-making of control activities.