75 results on '"JONG HO AHN"'
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2. A study on the dimensionless design and efficiency analysis of rainwater harvesting system
- Author
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Jong-Ho Ahn and Sang-Eun Lee
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- 2022
3. Clinical Effects of Non-damaging Retinal Laser Therapy in Chronic Central Serous Chorioretinopathy
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Dong Heun Nam, Jong Ho Ahn, Ye Won Kim, Ki Woong Lee, and Dae Yeong Lee
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Ophthalmology ,medicine.medical_specialty ,chemistry.chemical_compound ,Laser therapy ,chemistry ,business.industry ,Medicine ,Retinal ,business ,Chronic central serous chorioretinopathy - Published
- 2021
4. Effect of Cyberknife Radiosurgery for Elderly Patients with Trigeminal Neuralgia
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Jong-Ho Ahn, Seu-Ryang Jang, Minho Lee, Tae-Kyu Lee, Young Woo Kim, Chul Ji, Sang-Bok Lee, Eun-Hye Lee, Min-Soo Kim, Dong-Eon Lee, and Jae-Jeon Shin
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medicine.medical_specialty ,business.industry ,Trigeminal neuralgia ,Medicine ,General Medicine ,CyberKnife Radiosurgery ,Radiology ,business ,medicine.disease - Published
- 2020
5. Impact of Regional Characteristics on Traffic Safety by Aging Stage
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Tae-yang Kim, Jong-ho Ahn, and Byung-Ho Park
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medicine.medical_specialty ,Injury control ,Accident prevention ,business.industry ,Injury prevention ,Emergency medicine ,medicine ,Poison control ,Human factors and ergonomics ,Stage (cooking) ,business ,Suicide prevention ,Occupational safety and health - Published
- 2020
6. Effect of the Combination Treatment of Injection to Scar and Intercostal Nerve Block for Patients with Post-Zoster Neuralgia on the Trunk
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Sang-Bok Lee, Tae-Kyu Lee, Seu-Ryang Jang, Jong-Ho Ahn, and Young Woo Kim
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Post-zoster neuralgia ,medicine.medical_specialty ,Combined treatment ,business.industry ,Medicine ,General Medicine ,business ,Trunk ,Surgery ,Intercostal nerve block - Published
- 2019
7. Effects of Selenium Injection on the Reproductive Performance of Holstein Dairy Cows
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Gil Woo Han, In Sik Nam, and Jong Ho Ahn
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Animal science ,General Veterinary ,chemistry ,chemistry.chemical_element ,Animal Science and Zoology ,Biology ,Selenium - Published
- 2021
8. Effects of Feeding Total Mixed Ration in the Growing and Fattening Periods on the Growth and Carcass Characteristics of Hanwoo Steers
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In Sik Nam, Jong Ho Ahn, and Jang Hoon Choi
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Animal science ,Hanwoo ,Total mixed ration ,Biology ,General Agricultural and Biological Sciences - Published
- 2021
9. Study on the Radiation Dose of Abdominal CT Scan Using Dual Energy
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Dae-hyun Park, Young-Kyoon Kim, Jong-Ho Ahn, Kwang-Hyun Chang, Yoon-Chul Nam, and Mi-Sub Ahn
- Published
- 2018
10. UQ eSpace
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Jong-ho Ahn
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chemistry.chemical_classification ,Calliandra ,Leucaena ,Animal science ,chemistry ,biology ,Albizia chinensis ,Acacia angustissima ,Tannin ,Condensed tannin ,biology.organism_classification ,Gliricidia sepium ,Gliricidia - Abstract
A series of experiments were conducted to investigate the nutritional value of tropical browse legumes. The presence of possible deleterious substances in freeze-dried leaf meal produced from Leucaena leucoceohala, Calliandra calothrvsus, Albizia chinensis, Tiouana tiou, Acacia saliana and Gliricidia sepium was evaluated using female rats. Each of the legume leaf meals were included in a commercial rat diet at a level of 0.20. Rats fed the diets containing Leucaena leaf meal and Gliricidia leaf meal exhibited significantly reduced intakes. Apart from those fed the commercial diet the rats fed the experimental diets lost liveweight. Greatest liveweight losses were recorded in rats fed the diet containing Gliricidia (-5.8 g/d) and Calliandra (-2.2 g/d). Rats fed these diets also exhibited reduced foetal numbers. This parameter was also reduced in rats fed the diet containing Tipuana tipu. In a subsequent experiment, an investigation of the extent to which different methods of tannin estimation are reliable was made in order to evaluate the nutritional effects of tannins on feed quality of 12 species of tropical browse legumes. Large variation existed in total phenolic content of the species examined (2.3-20.0%, freeze dried). Drying at 60o C resulted in a lower total phenolic content in most species, but the extent of the depressions was highly variable (2.7-90.0%). Condensed tannin content was also variable between species depending on the analytical method. Acacia angustissima which did not register an anthocyanidin content using butanol-HCl method was found to have condensed tannins (6% DM) when assayed by vanillin-HCl.
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- 2019
11. Effect of Spinal Cord Stimulation for Patients with Post-Zoster Neuralgia on the Trunk: A Case Report
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Seu-Ryang Jang, Jong-Ho Ahn, Tae-Kyu Lee, Sang-Bok Lee, and Young Woo Kim
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Post-zoster neuralgia ,business.industry ,Anesthesia ,Medicine ,General Medicine ,Spinal cord stimulation ,business ,Trunk - Published
- 2019
12. Authors’ reply
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Mee Kum Kim, Jong Ho Ahn, Dong Hyun Kim, Won Ryang Wee, Hae Jung Paik, and Yoon-Hyeong Choi
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Adult ,Male ,sex differences ,medicine.medical_specialty ,Letter ,National Health and Nutrition Examination Survey ,Cross-sectional study ,Population ,Disease ,Logistic regression ,Young Adult ,03 medical and health sciences ,Sex Factors ,0302 clinical medicine ,Surveys and Questionnaires ,Internal medicine ,Republic of Korea ,Prevalence ,risk factors ,Humans ,Medicine ,Risk factor ,Young adult ,education ,previous ocular surgery ,Aged ,Original Research ,education.field_of_study ,business.industry ,aging ,Age Factors ,General Medicine ,Odds ratio ,Middle Aged ,Nutrition Surveys ,dry eye disease ,Cross-Sectional Studies ,Logistic Models ,Socioeconomic Factors ,Clinical Interventions in Aging ,030221 ophthalmology & optometry ,Female ,Dry Eye Syndromes ,Geriatrics and Gerontology ,business ,030217 neurology & neurosurgery - Abstract
Jong Ho Ahn,1 Yoon-Hyeong Choi,2 Hae Jung Paik,1 Mee Kum Kim,3 Won Ryang Wee,3 Dong Hyun Kim1 1Department of Ophthalmology, Gachon University Gil Medical Center, 2Department of Preventive Medicine, Gachon University College of Medicine, Incheon, 3Department of Ophthalmology, Seoul National University College of Medicine, Seoul, South Korea Purpose: Aging is a major risk factor in dry eye disease (DED), and understanding sexual differences is very important in biomedical research. However, there is little information about sex differences in the effect of aging on DED. We investigated sex differences in the effect of aging and other risk factors for DED.Methods: This study included data of 16,824 adults from the Korea National Health and Nutrition Examination Survey (2010–2012), which is a population-based cross-sectional survey. DED was defined as the presence of frequent ocular dryness or a previous diagnosis by an ophthalmologist. Basic sociodemographic factors and previously known risk factors for DED were included in the analyses. Linear regression modeling and multivariate logistic regression modeling were used to compare the sex differences in the effect of risk factors for DED; we additionally performed tests for interactions between sex and other risk factors for DED in logistic regression models.Results: In our linear regression models, the prevalence of DED symptoms in men increased with age (R=0.311, P=0.012); however, there was no association between aging and DED in women (P>0.05). Multivariate logistic regression analyses showed that aging in men was not associated with DED (DED symptoms/diagnosis: odds ratio [OR] =1.01/1.04, each P>0.05), while aging in women was protectively associated with DED (DED symptoms/diagnosis: OR =0.94/0.91, P=0.011/0.003). Previous ocular surgery was significantly associated with DED in both men and women (men/women: OR =2.45/1.77 [DED symptoms] and 3.17/2.05 [DED diagnosis], each P
- Published
- 2017
13. Effects of Feeding Total Mixed Ration in the Growing and Fattening Periods on the Growth and Carcass Characteristics of Hanwoo Steers.
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Jong Ho Ahn, Jang Hoon Choi, and In Sik Nam
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CATTLE carcasses , *CONCENTRATE feeds , *MEAT quality , *BEEF cattle , *RATIONING , *ERECTOR spinae muscles - Abstract
Sixty Hanwoo steers of average weight and average age 6.5 months were raised until the age of 18 months (growing period, G) and from the age of 19 months to 30.85-31.52 months (fattening period, F). They were separately fed concentrate and forage (C) or total mixed ration (TMR, T) in the growing and fattening periods. The treatments were GCFC (Concentrate feeding in the growing and fattening periods), GCFT (Concentrate feeding in the growing period and TMR feeding in the fattening period), GTFC (TMR feeding in the growing period and concentrate feeding in the fattening period) and GTFT (TMR feeding in the growing and fattening periods) in a completely randomized design. Dry matter intake (p < 0.001) in the growing period was higher in the GCFC and GCFT groups than in the other groups, whereas DMI of TMR feeding (GCFT and GTFT) during fattening period increased by 3.3% (p < 0.001). The longissimus dorsi muscle area (LMA, 94.20 vs. 96.73 cm²) and back fat thickness (BFT 17.33 vs. 16.93 mm) were not significantly affected during fattening period among different treatments. Marbling score, which substantially affects meat quality, the GCFT and GTFT groups in the fattening period presented higher than the GTFC and GCFC groups. The incidence of C grade of meat yield was 33.3% with GCFC and GTFC) and 40.0% with GCFT and GTFT). The incidence of grade 1+ or higher meat quality was higher with (GCFT, 86.6%; GTFT, 73.3%) than (GCFC, 46.7%; GTFC, 66.6%) in the fattening period. In conclusion, feeding TMR to beef cattle has been shown to have a positive effect on productivity. Therefore, it is expected that TMR can help to improve the competitiveness of beef cattle farms. [ABSTRACT FROM AUTHOR]
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- 2021
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14. Effects of Dicarboxylic Acid as an Alternative toAntibiotic on in vitro Rumen Parameters, Milk yield andMilk Compositions in Lactating Cows
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In-Sik Nam, Ki-Hwan Jeong, Yong-Dae Ahn, and Jong-Ho Ahn
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chemistry.chemical_classification ,Rumen ,Milk yield ,Dicarboxylic acid ,Chemistry ,Food science ,In vitro - Published
- 2016
15. A Protocol to Acquire the Degenerative Tenocyte from Humans
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Chihoon Oh, Geunhee Ye, Kyunghoon Min, Dong Hyeon Lee, Soonchul Lee, Jong-Ho Ahn, Soo-Hong Han, Minjung Baek, Joong-Myung Lee, and Hyung Kyung Kim
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Pathology ,medicine.medical_specialty ,General Chemical Engineering ,General Biochemistry, Genetics and Molecular Biology ,Tendons ,03 medical and health sciences ,0302 clinical medicine ,Biopsy ,medicine ,Animals ,Humans ,Pathological ,Cells, Cultured ,030203 arthritis & rheumatology ,030222 orthopedics ,medicine.diagnostic_test ,General Immunology and Microbiology ,business.industry ,General Neuroscience ,Hyperplasia ,medicine.disease ,Tendon ,Tenomodulin ,Tenocytes ,medicine.anatomical_structure ,Dysplasia ,Tendinopathy ,Medicine ,Stem cell ,business - Abstract
Tendinopathy, a painful condition that develops in response to tendon degeneration, is on the rise in the developed world due to increasing physical activity and longer life expectancy. Despite its increasing prevalence, the underlying pathogenesis still remains unclear, and treatment is generally symptomatic. Recently, numerous therapeutic options, including growth factors, stem cells, and gene therapy, were investigated in hopes of enhancing the healing potency of the degenerative tendon. However, the majority of these research studies were conducted only on animal models or healthy human tenocytes. Despite some studies using pathological tenocytes, to the best of our knowledge there is currently no protocol describing how to obtain human degenerative tenocytes. The aim of this study is to describe a standard protocol for acquiring human degenerative tenocytes. Initially, the tendon tissue was harvested from a patient with lateral epicondylitis during surgery. Then biopsy samples were taken from the extensor carpi radialis brevis tendon corresponding to structural changes observed at the time of surgery. All of the harvested tendons appeared to be dull, gray, friable, and edematous, which made them visually distinct from the healthy ones. Tenocytes were cultured and used for experiments. Meanwhile, half of the harvested tissues were analyzed histologically, and it was shown that they shared the same key features of tendinopathy (angiofibroblastic dysplasia or hyperplasia). A secondary analysis by immunocytochemistry confirmed that the cultured cells were tenocytes with the majority of the cells having positive stains for mohawk and tenomodulin proteins. The qualities of the degenerative nature of tenocytes were then determined by comparing the cells with the healthy control using a proliferation assay or qRT-PCR. The degenerative tenocyte displayed a higher proliferation rate and similar gene expression patterns of tendinopathy that matched previous reports. Overall, this new protocol might provide a useful tool for future studies of tendinopathy.
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- 2018
16. Serological and molecular prevalence of canine vector-borne diseases (CVBDs) in Korea
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Guk-Hyun Suh, Kyu-Sung Ahn, Ha-Jung Kim, Jong-Ho Ahn, Sung-Shik Shin, and Christian M. Leutenegger
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Bartonella ,Male ,Veterinary medicine ,040301 veterinary sciences ,Ehrlichia canis ,Rhipicephalus sanguineus ,030231 tropical medicine ,Short Report ,Dirofilaria immitis ,Tick ,0403 veterinary science ,03 medical and health sciences ,0302 clinical medicine ,Dogs ,Seroepidemiologic Studies ,parasitic diseases ,Republic of Korea ,Prevalence ,Animals ,Dog Diseases ,Korea ,biology ,Ehrlichia ,Neorickettsia risticii ,04 agricultural and veterinary sciences ,biology.organism_classification ,Anaplasma phagocytophilum ,Haemotropic mycoplasma ,Insect Vectors ,Infectious Diseases ,Serology ,Canine vector-borne diseases (CVBD) ,Parasitology ,Female ,Real-time PCR - Abstract
Background Previous surveys in dogs from Korea indicated that dogs are exposed to a variety of vector- borne pathogens, but perception for a nation-wide canine vector-borne disease (CVBD) occurrence has been missing. We report here results of both serological and molecular prevalence studies for major CVBDs of dogs from all over the South Korean Peninsula except for Jeju Island. Results Serological survey of 532 outdoor dogs revealed the highest prevalence for Dirofilaria immitis (25.2%), followed by Anaplasma phagocytophilum (15.6%), Ehrlichia canis (4.7%) whereas Borrelia burgdorferi showed the lowest prevalence (1.1%). The number of serologically positive dogs for any of the four pathogens was 216 (40.6%). Concurrent real-time PCR assay of 440 dogs in the study indicated that DNA of “Candidatus M. haematoparvum”, Mycoplasma haemocanis, Babesia gibsoni, A. phagocytophilum, and Hepatozoon canis was identified in 190 (43.2%), 168 (38.2%), 23 (5.2%), 10 (2.3%) and 1 (0.2%) dogs, respectively. DNA of Bartonella spp., Ehrlichia spp., Leishmania spp., Rickettsia spp. and Neorickettsia risticii was not identified. Analysis of questionnaires collected from owners of 440 dogs showed that the number of dogs with heartworm preventive medication was 348 (79.1%) among which dogs still positive to D. immitis infection were 60 (17.2%), probably due to the mean months of heartworm preventive medication being only 6.5. The high prevalence rates of both “Ca. M. haematoparvum” and Mycoplasma haemocanis in dogs from Korea indicate that these organisms may be transmitted by vectors other than Rhipicephalus sanguineus because this tick species has rarely been found in Korea. This is the first nationwide survey for canine haemotropic mycoplasma infections in Korea. Conclusions This study showed that the risk of exposure to major vector-borne diseases in dogs is quite high throughout all areas of South Korean Peninsula. Since achieving full elimination of many pathogens causing CVBDs from infected animals is often impossible even when they are clinically cured, dogs once exposed to CVBDs can remain as lifetime reservoirs of disease for both other animals and humans in the close vicinity, and should therefore be treated with preventative medications to minimise the risk of pathogen transmission by the competent vectors.
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- 2017
17. Analysis of HACCP System Implementation on Productivity, Advantage and Disadvantage of Laying Hen Farm in Korea
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Hyung Sik Kim, In Sik Nam, Jong Ho Ahn, and Kang Min Seo
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Business ,Marketing ,Productivity ,Laying ,Implementation ,Disadvantage ,Industrial organization - Published
- 2014
18. Using Computed Tomography: Predictive Factors for Recovery Time in Patients with Orbital Fracture with Diplopia
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Mi Jung Chi, Su Jin Park, and Jong Ho Ahn
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Diplopia ,Ophthalmology ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,medicine ,Computed tomography ,In patient ,Radiology ,medicine.symptom ,business ,Orbital Fracture - Published
- 2019
19. Effects of Feeding Herbaceous Peat on Growth Performance and Meat Quality of Holstein Beef Cattle
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Hong-Yun Kim, Joong-Kook Park, and Jong-Ho Ahn
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Peat ,Agronomy ,media_common.quotation_subject ,Quality (business) ,Beef cattle ,Biology ,Herbaceous plant ,media_common - Published
- 2013
20. Effects of Dietary Herbaceous Peat and Vitamin C on Immunity and Growth Performance in Holstein Calves
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Hong-Yun Kim, Jong-Ho Ahn, and Joong-Kook Park
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Diarrhea ,Peat ,Agronomy ,Vitamin C ,Immunity ,medicine ,Herbaceous plant ,Biology ,medicine.symptom - Published
- 2012
21. Hydrologic and Water Quality Responses to Precipitation Extremes in Nakdong River Basin
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Jae Ho Jang and Jong Ho Ahn
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Pollutant ,Wet season ,Hydrology ,geography ,geography.geographical_feature_category ,Flood myth ,Drainage basin ,Environmental science ,SWAT model ,Precipitation ,Water quality ,Surface runoff - Abstract
SWAT model is applied to simulate rainfall-runoff and pollutant loadings in the Nakdong River basin as the condition for extreme droughts and floods. The year 1994 and 2002 are chosen as the drought and flood year, respectively, through the analysis of past rainfall data for 30 years. The simulation results show decreases in both runoff and pollutant loadings for the drought year but increases for the flood year. However, the pollutant loadings on some upper sub-basins increase for drought year due to highly-regulated dam discharge and soil moisture change. Collectively, extreme droughts and floods have negative impacts on water quality, showing elevated SS loadings during wet season and concentrated T-P concentrations during low flow season. The extent of these impacts is highly influenced by antecedent dry days and precipitation patterns.
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- 2012
22. Identifying Suspended Particulate Matters in an Urban Coastal System: Significance and Application of Particle Size Analysis
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Jong Ho Ahn
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Hydrology ,Environmental Engineering ,Turbidity current ,Environmental science ,Empirical orthogonal functions ,Outflow ,Particle size ,Particulates ,Turbidity ,Surface runoff ,Plume - Abstract
In situ particle size spectra are obtained from two sequent cruises in order to evaluate the physical consequences of suspended particulate matters caused by episodic storm runoff from the Santa Ana River watershed, an urbanized coastal watershed. Suspended particles from various sources including surface runoff, near-bed resuspension, and phytoplankton are identified in empirical orthogonal function (EOF) analysis and an entropy-based parameterization (Shannon entropy). The first EOF mode is associated with high turbidity and fine particles as indicated by the elevated beam attenuation near the Santa Ana River and Newport Bay outlets, and the second EOF mode explains the suspended sediment dispersal and particle coarsening at the near-surface plume. Chlorophyll particles are also distinguished by negative magnitudes of the first EOF mode, which is supported by the relationship between fluorescence and beam attenuation. The integrated observation between the first EOF mode and the Shannon entropy index accentuates the characteristics of two different structures and/or sources of sediment particles; the near-surface plumes are originated from runoff water outflow, while the near-bottom particles are resuspended due to increased wave heights or mobilizing bottom turbidity currents. In a coastal pollution context, these methods may offer useful means of characterizing particle-associated pollutants for purposes of source tracking and environmental interpretation.
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- 2012
23. Cost benefit analysis of introducing domestic food waste disposers on waste and sewage management systems
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Jong-Ho Ahn
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Food waste ,Cost–benefit analysis ,Waste management ,business.industry ,Management system ,Market price ,Capital cost ,Sewage ,Economic impact analysis ,Business ,Agricultural economics ,Externality - Abstract
The use of food waste disposers (FWDs) can be an emerging option to manage organic food wastes in municipal sewage system. The cost-benefit analysis (CBA) of introducing domestic FDWs is conducted to access the allowable disposer market price and the economic impact on food waste management from conventional solid waste management system. If the convenience value of 10,000 won/month is taken into consideration based on survey results, the introduction of FDWs can lead to net economic benefits, allowing the capital cost of disposer up to 1,000,000 won/unit. Without the consideration of convenience value, the introduction of FWDs becomes profitable if the capital cost of disposer is less than 50,000 won/unit. In case that the value of convenience is more than 7,000 won/month, the reduction of food waste management cost is not valid for the introduction of FWDs to be non-profitable. However, if environmental externalities are considered, the proposed system could become breakeven with the cost of food waste management decreases by 54 % (60,000 won per ton).
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- 2012
24. Prediction of Chlorophyll-a Changes due to Weir Constructions in the Nakdong River Using EFDC-WASP Modelling
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Mi Nae Kim, Jong Ho Ahn, and Dongil Seo
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Biochemical oxygen demand ,Hydrology ,Chlorophyll a ,chemistry.chemical_compound ,Environmental Engineering ,Nutrient ,chemistry ,Hydraulic retention time ,Phytoplankton ,Environmental science ,Water quality modelling ,Water quality ,Eutrophication - Abstract
To evaluate the effect of the 4 major rivers restoration project in the Nakdong River to water quality of the river, the Environmental Fluid Dynamics Code (EFDC) and Water Quality Analysis Simulation Program (WASP), are applied in series. Results showed overall decrease in biochemical oxygen demand (BOD5) concentrations and increase in chlorophyll-a concentrations, while total nitrogen and total phosphorous concentrations did not show significant changes, relatively. Decrease in BOD 5 concentrations seems to be influenced by an increased hydraulic residence time, which may allow more time for the degradation of organic material. Changes in Chlorophyll-a (Chl-a) concentration, due to the project were more significant for the upper stream areas that show relatively low Chl-a concentration ranges (less than 20 g/L). After the introduction of the Geumho River in the middle part of the Nakdong River, rapid growth of phytoplankton was observed. However, in this middle part of the Nakdong River, the ratio of Chl-a concentration change are less significant, compared to the upper stream areas, due to the project. In the lower stream area, Chl-a concentration decreased after the project. This seems to be resulted from the decreased light availability, due to increased depth, while the nutrient concentrations have been high enough to support phytoplankton growth.
- Published
- 2012
25. Size distribution and settling velocities of suspended particles in a tidal embayment
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Jong Ho Ahn
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Time Factors ,Environmental Engineering ,Entropy ,Mineralogy ,California ,Suspensions ,Settling ,Tributary ,Water Movements ,Particle Size ,Waste Management and Disposal ,Water Science and Technology ,Civil and Structural Engineering ,Hydrology ,geography ,geography.geographical_feature_category ,Geography ,Ecological Modeling ,Estuary ,Pollution ,Debris ,Bays ,Particle-size distribution ,Particle ,Particle size ,Water Microbiology ,Bay ,Water Pollutants, Chemical ,Geology - Abstract
Field studies were carried out to investigate seasonal and bay-wide variations in the particle size distributions (PSDs) and settling velocities of suspended particles in Newport Bay, the second largest tidal embayment in southern California. Maximum Entropy Classification (MEC) of the data identified three PSD groups: (1) suspended particles with a single mode around 10–20 μm (Group 1), (2) suspended particles with a single mode similar to Group 1, but shifted to smaller particle sizes (Group 2), and (3) suspended particles with a coarse mode at around 100 μm (Group 3). The three PSD groups have distinct seasonal and spatial patterns, and different size-settling velocity relationships, consistent with the hypothesis that Newport Bay longitudinally fractionates allochthonous particles from its tributaries by both size and settling velocity, and generates large and fast settling autochthonous particles, probably in the form of biological debris. Particle concentrations in Groups 1 and 2 are significantly correlated with fecal indicator bacteria, suggesting possible linkages between fecal pollution and particle transfer in this tidal embayment.
- Published
- 2012
26. Urban Instream Flow Augmentation Using Reclaimed Water in Korea
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Jong-Ho Ahn, Yong-Keun Jee, and Jin-Hee Lee
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Current (stream) ,Watershed ,Urban stream ,business.industry ,Environmental engineering ,Environmental science ,Sewage ,Sewage treatment ,STREAMS ,Reuse ,Water resource management ,business ,Reclaimed water - Abstract
Current urban stream conditions and their restoration projects were investigated by surveying the urban stream management experts in 29 cities with high population density (more than 1,000person/). The survey results showed that the ratio of covered urban streams decreased by 1.4% (from 14% to 12.6%) in the last 5 years through steady river restoration projects promoted by governments. Nonetheless, 36.3% of 369 urban streams surveyed still report stream depletion problems; therefore, more efforts to alleviate the problems caused by distorted water circulation of urban streams are still necessary. Water depletion in many local urban streams, unlike national rivers, is accelerated due to negligence in stream management, budget shortage, and other reasons. To prevent stream depletion, the use of reclaimed water is suggested as one of the prevention plans. When available amounts of reused sewage are estimated through actual available nationwide sewage discharges of each watershed and instream flow of stream, annual instream flow supply of 780 million is expected; 4.8% reduction in the pollution load of public sewer treatment facilities is expected; and the creation of new value through water reuse service is expected. Thus, it is important for the reviews of feasibility and alternatives of water reuse projects for flow augmentation to consider not only investment budget reductions, but also environmental aspects. Also it is necessary to provide the financial support of unified government with strict water quality management policy.
- Published
- 2012
27. Shedding and size distributions of suspended sediments in an urban watershed
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Jong Ho Ahn
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Hydrology ,Watershed ,Sediment ,Ocean Engineering ,Storm ,Pollution ,Sediment concentration ,Fractal ,Storm water runoff ,Environmental science ,Geotechnical engineering ,Particle size ,Sediment transport ,Water Science and Technology - Abstract
Particle size spectra of suspended sediment eroded from the Santa Ana River, a human-impacted urban river in southern California are investigated to consider fractal behaviors in suspended sediment transport. Widespread urbanization has fueled hydrological change of the watershed over four decades, showing significant increases in storm water runoff with decreases in instantaneous suspended sediment concentration. In-site observation of particle size distributions (PSDs) during three storm studies reveals two transport regimes (flow-controlled or bedcontrolled) depending on whether average particle size increase (flow-controlled) or decrease (bed-controlled) with flow rate. Despite their complexity, the observed PSDs exhibit power-law mass-size statistics, and satisfy fractal (power-law) scaling in a very robust manner. The evolution of PSD to a stable form with asymptotic behavior in suspended sediments suggests that shedding of suspended sediments in urban watershed environment system has its o...
- Published
- 2012
28. Effects of Feeding Whole-Crop Barley Silage and Corn Silage on Nutrients Availability, Growth Performance and Blood Parameters in Korean Black Goats
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Min-Ki Park, Jong-Ho Ahn, Ik-Hwan Jo, and Soon HwanBo
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chemistry.chemical_classification ,Crop ,Nutrient ,Animal science ,chemistry ,Agronomy ,Feed consumption ,Silage ,Dry matter ,Organic matter ,Blood parameters ,Body weight - Abstract
*ABSTRACTThis study examined the effects of feeding whole-crop barley silage(BS), corn silage(CS) and the mixture of BS and CS(CB) on feed consumption, daily gain, nutrients apparent digestibilities and blood parameters in order to investigate the feed evaluation in Korean black goats. BS, CS, and CB were fed to twelve Korean black goats, which were allocated into three groups in metabolic cages according to the latin-square design. As a result, dry and organic matter intakes for goats per day have shown a tendency to decrease in the order of CS, CB and BS, but there were no significant differences. We also found a similar tendency when the intakes of crude protein, crude fat, and non-fiber carbohydrates(NFC) were examined. However, ADF and NDF consumptions showed a decreasing tendency in the order of CB, BS and CS. Dry matter intakes per metabolic body weight showed the decreasing tendency in the order of CS (57.6g), CB(53.8g) and BS(52.7g), however with no statistical differences. Average daily gain of 64.2g in CB was significantly higher than the other groups(42.0g to 46.0g). Nitrogen intakes and nitrogen retention showed a decreasing tendency in the order of CS, CB and BC. Nevertheless, nitrogen retention in CS group was higher by 30% than that of the BC group with p
- Published
- 2011
29. Numerical Estimations of Nakdong River Flows Through Linking of Watershed and River Flow Models
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Hyeongsik Kang, Jae-Ho Jang, Jong-Ho Ahn, and Ik-Jae Kim
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Hydrology ,geography ,geography.geographical_feature_category ,Watershed ,Streamflow ,Tributary ,Drainage basin ,Environmental science ,Estuary ,Water quality ,SWAT model ,Surface runoff - Abstract
In this study, the watershed and water body models were linked for the simulation of the Nakding river flow. This is a pre-step study for the estimation of the effect of the flow and water quality on the climate change. For models of watershed and river flow, the SWAT and EFDC were used, respectively. The runoff discharge at each boundary points for the simulation of the river flow was provided from the drainage basin model. The calculated runoff discharge by the SWAT model was compared with the measured data of the Ministry of Environment at 13 locations along the Nakdong river and 30 locations along the tributary streams. The computed water discharge was shown to be similar with the measured data. For the model calibration and verification, % difference, NSE, and were computed. The computed % difference was within 15% except of a few points. The NSE and were also within a fair level. The Nakdong river flow of 2007 was simulated by using the EFDC model. The comparison with the measured data showed that the model reflected the actual values of low and high flow well. Also, it was confirmed that the acceleration and deceleration in the curved areas were appropriately simulated. The movement of dye injected at the upstream boundary was simulated. The result showed that the arrival time up to the estuary dam was computed to be about 65 days.
- Published
- 2011
30. Effects of Dietary Herbaceous Peat on In Vitro Fermentation and Milk Production in Dairy Cows
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Hong Yun Kim, Sang Bum Kim, Hyeon Shup Kim, Joong Kook Park, Chang-Hyun Kim, Jong Ho Ahn, and Seung Hak Yang
- Subjects
food and beverages ,Biology ,Herbaceous plant ,Rumen ,chemistry.chemical_compound ,Horticulture ,Animal science ,medicine.anatomical_structure ,NEFA ,chemistry ,Lactation ,medicine ,Hay ,Liver function ,Lactose ,Somatic cell count - Abstract
This study was conducted to determine effects of dietary herbaceous peat on invitrofermentation andmilk production in dairy cows. Ruminal pH, gas production, VFA(volatile fatty acid), Ammonia-N, andrumen degradability were examined by the addition of three times over 0, 1, and 5% herbaceous peat withsubstrate of timothy hay, and the change of rumen fermentation characteristics were evaluated. In 0, 3, 12and 24 hours cultivation, all treatments did not show a significant difference but the control at 6 hoursappeared significantly lower pH compared to 1 and 5% treatments(p
- Published
- 2011
31. Evaluation of Chemical, Molecular, and Traditional Markers of Fecal Contamination in an Effluent Dominated Urban Stream
- Author
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Stanley B. Grant, Bram Sercu, Patricia A. Holden, David L. Sedlak, Rachel M. Litton, and Jong Ho Ahn
- Subjects
Hydrology ,biology ,business.industry ,Urbanization ,Indicator bacteria ,Sewage ,General Chemistry ,biology.organism_classification ,Polymerase Chain Reaction ,Coliform bacteria ,Fecal coliform ,Feces ,Wastewater ,Enterococcus ,Environmental chemistry ,Environmental Chemistry ,Water Pollutants ,business ,Water pollution ,Effluent - Abstract
In this paper we present a quantitative sanitary survey of the Middle Santa Ana River, in southern California, utilizing a variety of source tracking tools, including traditional culture-dependent fecal markers (Enterococcus and Escherichia coli by IDEXX), speciation of enterococci isolates, culture-independent fecal markers (human-specific HF183 Bacteroides and Enterococcus by quantitative polymerase chain reaction, qPCR), and chemical markers of sewage and wastewater (nutrients, enantiomeric fraction (EF) of propranolol and ethylenediaminetetraacetic acid). To facilitate comparison of these different methods, data are interpreted in a loading (i.e., mass per time) framework that enables a quantitative apportionment of fecal markers and nutrients to specific source waters in the Middle Santa Ana River. Multiple lines of evidence support the hypothesis that Enterococcus in the Middle Santa Ana River originates primarily from in situ growth in streambed sediments, not from significant and persistent sources of untreated human waste. The EF of propranolol of tertiary treated wastewater effluent is in the range (0.42 to 0.71) previously reported for raw sewage, making EF of propranolol an unsuitable marker for fecal pollution, at least at this site. The human fecal marker HF183 Bacteroides was detected at a few sites, although not in a source of disinfected and tertiary treated wastewater effluent. Based on the results presented here and prior experience at other sites in southern California, HF183 Bacteroides would appear to be a candidate marker of fecal contamination for inland waters, although more qPCR measurements in disinfected wastewater effluent are needed to account for variations due to treatment plant performance and other factors. More generally, our results support the notion that regrowth of fecal indicator bacteria (FIB) in river sediments may lead to a decoupling between FIB and pathogen concentrations in the water column and thus limit the utility of FIB as an indicator of recreational waterborne illness in inland waters.
- Published
- 2010
32. Effects of Supplementation of Fermented Colostrum on Growth and Occurrence of Diarrhea in Holstein Calves
- Author
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Jong Ho Ahn and Jung Kil Park
- Subjects
Ecology ,animal diseases ,Veterinary (miscellaneous) ,food and beverages ,Biology ,biology.organism_classification ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Coliform bacteria ,Lactic acid ,Diarrhea ,chemistry.chemical_compound ,fluids and secretions ,Animal science ,chemistry ,medicine ,Colostrum ,Animal Science and Zoology ,Fermentation ,Food science ,medicine.symptom ,reproductive and urinary physiology ,Dairy cattle ,Bacteria ,Food Science ,Average Body Weight Gain - Abstract
Jong Ho Ahn* and Jung Kil ParkDepartment of Dairy Science, Hankyong National UniversityABSTRACTIn this study, feeding fermented colostrum to Holstein calves was investigated to find out the effects on their growth and inhibition of diarrhea. The results of this study showed that the mixture of L. rhamnosus and E. faecium would be proper bacteria for fermentation of colostrum because of favorable odor, inhibition of coliform bacteria and high number of lactic acid bacterial count. Among the groups of calves fed 0, 5, 10 and 20% of fermented colostrums, average body weight gain for 28 days on feeding fermented colostrum were 16.6, 16.6, 17.4 and 18kg, respectively showing that calves fed 20% fermented colostrum achieved the highest body weight gain. Occurrence of diarrhea due to feeding various levels of fermented colostrum was also recorded. Three calves out of 5 suffered diarrhea in 0%, 5%, and 20% group, on the other hand, all 5 calves suffered diarrhea in 10% group. Diarrhea persisted for durations were 2.7, 2.4, 4.0, and 2.4 days in 0, 5, 10, and 20% group, respectively. Fermented colostrum did not prevent the occurrence of diarrhea.In overall, addition of fermented colostrum above 10% level showed favorable effects in gaining body weight under the conditions of adding more portions of the fermented colostrum either for 14 days or longer feeding period of the fermented colostrum. On the other hand, fermented colostrum showed no beneficial effect in prevention of diarrhea in this study.(Key words :Fermented colostrum, Holstein calves, Growth, Diarrhea)
- Published
- 2010
33. Long-term Surgical Outcomes of Initial Postoperative Overcorrection in Adults with Intermittent Exotropia
- Author
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Hae Jung Paik and Jong Ho Ahn
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Visual Acuity ,Ophthalmologic Surgical Procedures ,Group B ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Cover test ,Retrospective Studies ,Fixation (histology) ,Diplopia ,Depth Perception ,Vision, Binocular ,Overcorrection ,business.industry ,Medical record ,Middle Aged ,medicine.disease ,Surgery ,Stereoscopic acuity ,Outcome assessment ,Ophthalmology ,Treatment Outcome ,Oculomotor Muscles ,030221 ophthalmology & optometry ,Exotropia ,Female ,Original Article ,Minimum deviation ,medicine.symptom ,business ,030217 neurology & neurosurgery ,Follow-Up Studies - Abstract
Purpose To evaluate the relationship between initial postoperative overcorrection and long-term surgical success in exotropia patients. Methods The medical records of 46 patients who underwent surgery for intermittent exotropia after the age of 18 were enrolled. Enrolled patients also had at least 2 years of postoperative follow-up. Based on the initial postoperative deviation at distance measured by prism and the alternating cover test at 1 week, patients were assigned to one of the following groups: group A included patients who demonstrated any esodeviation, while group B included patients who showed orthophoria to exodeviation of 10 prism diopters. The records were analyzed to determine the preoperative deviation with stereoacuity and postoperative deviations with stereoacuity at the follow-up examinations at the following intervals: 1 week; 1, 3, and 6 months; and 1 and 2 years. A comparison between groups for demographic data and preoperative and postoperative angles of deviation was performed using analysis of variance. Results Of the 46 patients with intermittent exotropia included in this study, 18 (39%) belonged to group A, while 28 (73%) belonged to group B. The postoperative angle of deviation for distant fixation until 2 years of follow-up showed statistically significant differences in each group (p < 0.003 in all comparisons). The amount of exodrift until 2 years in group A (from −9.7 ± 6.1 to 1.6 ± 3.7) was greater than that in group B (from 2.0 ± 2.7 to 6.8 ± 5.6). The long-term surgical success rate within 2 years of surgery was significantly better in group A than in group B (p = 0.027). The number of patients with intermittent diplopia and the duration of diplopia were greater in group A (n = 8) than in group B (n = 2). Conclusions Long-term surgical success was achieved in 89% of patients who were initially overcorrected. Overcorrection of an average of 10 prism diopters at the first postoperative week was found to be associated with a more favorable long-term surgical outcome.
- Published
- 2018
34. Investigation of the Changes in Refractive Surgery Trends in Korea
- Author
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Dong Hyun Kim, Jong Ho Ahn, and Kyung Hwan Shyn
- Subjects
Adult ,Male ,medicine.medical_specialty ,genetic structures ,Presbyopia surgery ,medicine.medical_treatment ,Keratomileusis ,Phakic intraocular lens ,03 medical and health sciences ,0302 clinical medicine ,Laser-assisted subepithelial keratectomy ,Surveys and Questionnaires ,Ophthalmology ,Refractive surgery ,Republic of Korea ,medicine ,Humans ,Practice Patterns, Physicians' ,Societies, Medical ,Dioptre ,Excimer laser ,business.industry ,LASIK ,Refractive surgical procedures ,Presbyopia ,Middle Aged ,medicine.disease ,Ablation ,Laser in situ keratomileusis ,eye diseases ,Health Care Surveys ,030221 ophthalmology & optometry ,Female ,Lasers, Excimer ,Original Article ,sense organs ,Trends ,business ,030217 neurology & neurosurgery - Abstract
Purpose To evaluate changes in clinical practice in the field of refractive surgery in Korea over the past 10 years. Methods A survey consisting of 59 multiple-choice questions regarding the preferred types of refractive surgery, excimer laser machine, and presbyopia surgery was mailed to 742 members of the Korean Society of Cataract and Refractive Surgery in January 2016, and 50 members responded to the survey. These data were compared with the 2005 or 2007 survey results. Results The majority of respondents were in their 40s (54%), and the average number of refractive surgeries performed in one month was 53. The most commonly used excimer laser machine was the VISX S4 in both 2005 (32%) and 2015 (25%); however, a greater variety of machines (EX500 [18%], Allegretto wave Eye-Q [13%], AMARIS 750 [10%]) were used in 2015. The preferred corneal refractive surgery in 2015 was surface ablation (40%), representing a significant increase in its popularity compared to 2005 (15%) (p < 0.001). The popularity of laser in situ keratomileusis (LASIK) surgery decreased to 20% in 2015 compared to 48% in 2005 (p < 0.001). Eighty percent of LASIK procedures in 2015 were performed using femtosecond laser. In 2015, surface ablation and phakic intraocular lens implantation were preferred for the treatment of myopia less than -8 diopters and more than -8 diopters, respectively. The proportion of respondents performing presbyopia surgery in 2015 (76%) was significantly increased from 2007 (30%) (p < 0.001). Conclusions Over the past decade, the most commonly performed corneal refractive surgery has changed from LASIK to surface ablation, and there has been a significant increase in the popularity of presbyopia surgery.
- Published
- 2018
35. Effects of Supplementation of Vitamin A on Fermentation Pattern in the Rumen and Cellulose Degradability Ruminococcus flavefaciens
- Author
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Bo Ra Kim and Jong Ho Ahn
- Subjects
Vitamin ,animal structures ,Ecology ,biology ,Veterinary (miscellaneous) ,Microorganism ,biology.organism_classification ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Enzyme assay ,chemistry.chemical_compound ,Rumen ,chemistry ,Biochemistry ,biology.protein ,Animal Science and Zoology ,Dry matter ,Fermentation ,Food science ,Cellulose ,Bacteria ,Food Science - Abstract
Jong Ho Ahn and Bo Ra KimDepartment of Dairy Science, Hankyong National UniversityABSTRACTThe aim of this study was tofind out the effects of supplementation of vitamin A to the diets of high or low amounts of concentrates for ruminants. In the first experiment, ruminal fermentation patterns with the data of pH, VFA production and cellulose disappearance rates in the rumen in vitro were investigated. In the second experiment, enzyme activities, gas production and dry matter degradabilities using cellulolytic bacteria, Ruminococcus flavefaciens were investigated.Ruminal pH was higher in low amounts of concentrates than in high amounts of concentrates as expected, however, no significant differences were found. Cellulose disappearance rates improved in vitamin A addition particularly in early incubation time(before 24h) and also the production of volatile fatty acids increased in vitamin A addition. These trends were more evident in diets containing high amounts of concentrates than in low amounts of concentrates and it may indicate that vitamin A is more required in the diets of high amounts of concentrates. In the second experiment, gas production, enzyme activities and dry matter degradabilities using cellulolytic bacteria, Ruminococcus flavefaciens were not different between vitamin A added and non-added diets. Ruminococcus flavefaciens may not require additional vitamin A for its own growth.(Key words : Vitamin A, Ruminal fermentation, Ruminococcus flavefaciens, Concentrates)
- Published
- 2009
36. Effects of Freeze-dried Citrus Peel on Feed Preservation, Aflatoxin Contamination and In vitro Ruminal Fermentation
- Author
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I.S. Nam, Philip C. Garnsworthy, and Jong Ho Ahn
- Subjects
Aflatoxin ,Animal feed ,Bacterial growth ,Biology ,Microbiology ,Rumen ,chemistry.chemical_compound ,chemistry ,Animal Science and Zoology ,Fermentation ,Dry matter ,Food science ,Digestion ,Mycotoxin ,Food Science - Abstract
The objective of this study was to investigate antimicrobial activity, during the storage period, of animal feed and any effects on in vitro rumen digestion by supplementing different levels (5.55, 11.1, and 22.2 g/kg) of freeze dried citrus peel (FDCP) to the feed compared to untreated feed and feed treated with an antifungal agent (AA) at 0.05 g/kg. In a preservation test, feed supplemented with FDCP showed no deterioration over 21 days. Untreated feed and AA-treated feed, however, showed signs of deterioration after 16 days storage. Yellow colour and red colour, measured by spectro chromameter, decreased in the untreated and AA-treated feeds, but not in feed supplemented with FDCP. Aflatoxin was detected in untreated and AA-treated feeds at 16 days (8 ppb and 2 ppb) and 21 days (8 ppb and 4 ppb), but aflatoxin was not detected in the feed supplemented with FDCP. In a second experiment, fermentation by rumen microorganisms of FDCP (22.2 g/kg) and AA (0.05 g/kg) supplemented feeds was studied in vitro. Feeds were incubated with buffered rumen fluid for 3, 6, 9, 12, 24, and 48 h. Dry matter digestibility (DMD) and organic matter digestibility (OMD) were affected by treatment, but ammonia-N, total, and individual volatile fatty acids (VFA) were not adversely affected by treatment. In conclusion, the results indicated that FDCP might be useful for inhibiting microbial growth of animal feed during storage without disrupting rumen fermentation.
- Published
- 2009
37. Effects of Supplementation of Ruminally Protected Amino Acids on In vitro Ruminal Parameters and Milk Yield and Milk Composition of Dairy Cows in Mid-lactation
- Author
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In Sik Nam, Jong Min Lee, and Jong Ho Ahn
- Subjects
chemistry.chemical_classification ,Ecology ,Veterinary (miscellaneous) ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,In vitro ,Amino acid ,Milk yield ,medicine.anatomical_structure ,chemistry ,Lactation ,medicine ,Animal Science and Zoology ,Composition (visual arts) ,Food science ,Food Science - Abstract
본 연구는 보호아미노산 추가 공급이 비유중기 착유우의 반추위 발효 성상 및 유생산량과 유성분 등의 생산성 변화를 알아보기 위하여 in vitro 시험과 in vivo 시험을 각각 실시하였다. In vitro 시험은 각각 4g의 공시사료를 이용하였으며, 처리구에는 보호라이신(PRLys, 2.71 %)과 보호메치오닌(PRMet, 0.90%)을 3:1로 혼합하여 첨가한 후 48시간동안 배양한 후 처리구와 대조구의 pH와 건물소화율을 확인하였다. 또한 In vivo 시험은 3:1로 혼합한 보호라이신 (PRLys, 2.71%)과 보호메치오닌(PRMet, 0.90%) 100g을 1일 2회로 나누어 비유 중기 착유우에 오전과 오후 착유 시 정량급여 한 후 생산되는 우유의 양 그리고 유성분의 변화를 조사하였다. 아미노산의 추가 급여로 인한 in vitro 반추위 pH와 건물소화율은 배양시간이 경과함에 따라 감소하는 경향을 나타냈으나 대조구에 비하여 유의성은 나타나지 않았다. 따라서 본 연구에서 사용된 보호아미노산은 반추위 미생물의 건물분해 능력 등 반추위 발효성상에 악 영향을 미치지 않은 것으로 판단된다. 비유중기 착유우에 보호아미노산 급여기간에 따른 유생산량은 시간이 지남에 따라 대조구와 처리구에서 모두 감소하는 경향을 보였으나, 이는 시험기간이 경과함에 따른 착유일수 증가로 인한 자연감소로 보여지며, 대조구에서 보다 처리구에서의 유량감소율이 적었다. 4% FCM과 유단백생성량은 대조구에서 각각 11.25%, 11.09% 그리고 처리구에서 6.16%, 5.47%의 감소를 나타내어 대조구보다 처리구에서 감소 비율이 낮았다. 보호아미노산 첨가 시 우유중 지방생성량은 대조구(0.79kg)에 비하여 처리구(1.10kg)에서 유의한 차이를 나타내었다(P 【This study was undertaken to investigate the effects of ruminally protected amino acids (Methionine and Lysine) on in vitro ruminal parameters, and in vivo milk yield and milk composition in mid-lactating cows. In the first in vitro experiment, there were no statistical significances between treatments in ruminal pH and dry matter digestibility during various incubation times. In the second in vivo experiment, milk yield decreased by 11.92% in control and 5.68% in the treatment respectively, but decrease rate of milk yield in the treatment was lower than control. Milk yields naturally decreased as time goes by since the DIMs(Days in milk) of the cows in experiment were in mid-lactation period. 4% FCM(Fat corrected milk) and milk protein yields also, respectively, decreased by 11.25% and 11.09% in control and 6.16% and 5.47% in the treatment as compared with the intial. Milk protein and milk fat production were higher in the treatment(0.90kg, 1.10kg) than those of control(0.66kg, 0.79kg). Milk fat content significantly increased with supplementing protected amino acids as compared to control(P】
- Published
- 2008
38. Use of salinity mixing models to estimate the contribution of creek water fecal indicator bacteria to an estuarine environment: Newport Bay, California
- Author
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Jong Ho Ahn, Karen McLaughlin, Rachel M. Litton, and Stanley B. Grant
- Subjects
Salinity ,Water mass ,Environmental Engineering ,Indicator bacteria ,Fresh Water ,California ,Feces ,Enterobacteriaceae ,Tributary ,Escherichia coli ,Water Movements ,Water Pollutants ,Water pollution ,Waste Management and Disposal ,Ecosystem ,Water Science and Technology ,Civil and Structural Engineering ,Hydrology ,geography ,geography.geographical_feature_category ,Ecological Modeling ,Estuary ,Models, Theoretical ,Pollution ,Bacterial Typing Techniques ,Oceanography ,Environmental science ,Storm drain ,Water Microbiology ,Bay - Abstract
The contribution of freshwater discharge to fecal indicator bacteria (FIB) impairment of an estuarine environment can be approximated from simple, two end-member mixing models using salinity as a tracer. We conducted a yearlong time series investigation of Newport Bay, a regionally important estuarine embayment in southern California, assessing the concentrations of FIB, specifically Escherichia coli and enterococci bacteria, and salinity. In total, eight within-bay stations and one offshore control site were sampled nearly once per week and the three tributaries draining into Newport Bay were sampled approximately daily. Using salinity as a conservative tracer for water mass mixing and determining the end-member values of FIB in both the creek sites and the offshore site, we created a linear, two end-member mixing model of FIB within Newport Bay. Deviations from the mixing model suggest either an additional source of FIB to the bay (e.g. bird feces, storm drain discharge) or regrowth and/or die-off of FIB within the bay. Our results indicate that salinity mixing models can be useful in predicting changes in FIB concentrations in the estuarine environments and can help narrow the search for sources of FIB to the bay and enhance our understanding of the fate of FIB within the bay.
- Published
- 2007
39. Size Distribution, Sources, and Seasonality of Suspended Particles in Southern California Marine Bathing Waters
- Author
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Stanley B. Grant and Jong Ho Ahn
- Subjects
Shore ,geography ,geography.geographical_feature_category ,Mineralogy ,Empirical orthogonal functions ,General Chemistry ,Seasonality ,medicine.disease ,Atmospheric sciences ,Bathing Beaches ,Particle-size distribution ,medicine ,Environmental Chemistry ,Environmental science ,Seawater ,Particle size ,Surface runoff - Abstract
In this paper we define seasonal and along-shore variations in suspended particle size distributions (PSDs) at two marine bathing beaches in southern California, using a low-angle light scattering instrument (LISST). Empirical Orthogonal Function (EOF) analysis of the LISST data set (n = 55 651) identified three particle size modes that collectively account for > 90% of the variance in the de-meaned PSD data at six sites along the shoreline at Huntington Beach and Newport Beach: a dinoflagellate mode, a large particle mode, and a small particle mode. These three modes exhibit distinct seasonal patterns, and along-shore distributions, reflecting both the sources of particles and environmental factors that trigger their occurrence. Comparison of volume-based PSDs generated from the LISST and from image analysis of optical micrographs indicates that the LISST performs well when measuring the size distribution of particles associated with dinoflagellate blooms. However, LISST measurements on stormwater-impacted samples consistently yield a rising tail at small particle sizes that may be an artifact arising from the non-spherical nature of inorganic particles in terrestrial runoff. The results presented here demonstrate that PSDs measured by light scattering instruments such as the LISST represent a new data resource for assessing water quality, and managing human health risk, at marine bathing beaches.
- Published
- 2006
40. Supplementation of Essential Oil Extracted from Citrus Peel to Animal Feeds Decreases Microbial Activity and Aflatoxin Contamination without Disrupting In vitro Ruminal Fermentation
- Author
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Philip C. Garnsworthy, Jong Ho Ahn, and I.S. Nam
- Subjects
chemistry.chemical_classification ,Preservative ,Aflatoxin ,Animal feed ,food and beverages ,Biology ,Microbiology ,law.invention ,Rumen ,chemistry ,law ,Propionate ,Animal Science and Zoology ,Dry matter ,Fermentation ,Food science ,Essential oil ,Food Science - Abstract
Long-term storage of feeds or feedstuffs in high temperature and humid conditions can be difficult because of microbial contamination. Essential oil isolated from industrial waste citrus peel could be used as a preservative because it is likely to have anti-bacterial and anti-fungal activity. Our objective was to determine whether different levels (0.028, 0.056 and 0.112 g/kg) of citrus essential oil (CEO) would provide anti-microbial activity and enhance preservation of animal feed without influencing rumen fermentation. At 0.112 g/kg, CEO inhibited growth of Escherichia coli (ATCC 25922) and Salmonela enteritidis (IFO 3313). Growth of E. coli recovered after 24 h of incubation, but S. enteritidis continued to be inhibited for 72 h. Preservation of antibiotic-free diets for swine was assessed by observing anti-aflatoxin activity. Aflatoxin was detected in control feed samples on days 16 (8 ppb) and 21 (8 ppb) and in anti-fungal agent (AA) treated samples on days 16 (2 ppb) and 21 (4 ppb). However, aflatoxin was not detected in feed samples treated with CEO. Treatment with CEO and AA did not influence ruminal pH, dry matter digestibility (DMD) or organic matter digestibility (OMD) over 48 h of incubation in rumen fluid. Acetate and propionate were slightly higher with CEO treatment (p
- Published
- 2006
41. Flow Fingerprinting Fecal Pollution and Suspended Solids in Stormwater Runoff from an Urban Coastal Watershed
- Author
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Jong Ho Ahn, Stanley B. Grant, Cristiane Q. Surbeck, and Sunny C. Jiang
- Subjects
Hydrology ,Suspended solids ,Stormwater ,Indicator bacteria ,General Chemistry ,Coliphages ,California ,Feces ,Enterobacteriaceae ,Streamflow ,Environmental Chemistry ,Environmental science ,Water Pollutants ,Water pollution ,Surface runoff ,Surface water ,Total suspended solids - Abstract
Field studies were conducted to characterize the concentration vs streamflow relationships (or "flow fingerprints") of fecal pollution and suspended solids in stormwater runoff from the Santa Ana River watershed, the largest watershed in southern California. The concentrations of fecal indicator bacteria and F+ coliphages (viruses infecting E. coli) exhibit little-to-no dependence on streamflow rates, whereas the concentrations of total suspended solids (TSS) exhibit a very strong (power-law) dependence on streamflow rates. The different flow fingerprints observed for fecal pollutants, on one hand, and TSS, on the other hand, reflect different sources and transport pathways for these stormwater constituents. The flow-independent nature of fecal indicator bacteria and F+ coliphages is consistent with the idea that these contaminants are ubiquitously present on the surface of the urban landscape and rapidly partition into the surface water as the landscape is wetted by rainfall. The flow-dependent nature of TSS, on the other hand, is usually ascribed to the shear-induced erosion of channel bed sediments and/or the expansion of drainage area contributing to runoff. The apparent ubiquity of fecal indicator bacteria and F+ coliphages, together with the very high storm-loading rates of fecal indicator bacteria and the low detection frequency of human adenovirus and human enterovirus, suggest that fecal pollution in stormwater runoff from the Santa Ana River watershed is primarily of nonhuman waste origin.
- Published
- 2006
42. Design of experiment considering two-way interactions and its application to injection molding processes with numerical analysis
- Author
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Keun Park and Jong-Ho Ahn
- Subjects
Optimal design ,Engineering ,business.industry ,Design of experiments ,Numerical analysis ,Metals and Alloys ,Scheduling (production processes) ,Process (computing) ,Molding (process) ,medicine.disease_cause ,Industrial and Manufacturing Engineering ,Computer Science Applications ,Modeling and Simulation ,Mold ,Ceramics and Composites ,medicine ,Electronics ,Process engineering ,business ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
The optimal design for injection molding processes is sought by using the design of experiment (DOE) and numerical analysis. DOE is designed so as to consider two-way interactions, and have been applied progressively for both mold and process designs. Numerical analyses have been carried out as DOEs for mold parameters such as runner specifications and cooling channel configurations. In order to determine optimal process parameters, experiments have been performed for various process conditions with the DOE scheduling. As a result, the quality and productivity of the product have been improved, and the proposed approach can be successfully applied to the industrial injection molding process of precision electronics parts.
- Published
- 2004
43. Residual Stress Estimation and Deformation Analysis for Injection Molded Plastic Parts using Three-Dimensional Solid Elements
- Author
-
Chung-Hyuk Yim, Keun Park, and Jong-Ho Ahn
- Subjects
Lens (optics) ,Materials science ,law ,Residual stress ,Mechanical Engineering ,Numerical analysis ,Flow (psychology) ,Shell (structure) ,Molding (process) ,Deformation (meteorology) ,Composite material ,Finite element method ,law.invention - Abstract
Most of CAE analyses for injection molding have been based on the Mele Shaw`s approximation: two-dimensional flow analysis. in some cases, that approximation causes significant errors due to loss of the geometrical information as well as simplification of the flow characteristics in the thickness direction. Although injection molding analysis software using three-dimensional solid elements has been developed recently, such as Moldflow Flow3D, it does not contain a deformation analysis function yet. The present work covers three-dimensional deformation analysis or injection molded plastic parts using solid elements. A numerical scheme for deformation analysis has bun proposed from the results of injection molding analysis using Moldflow Flow3D. The accuracy of the proposed approach has been verified through a numerical analysis of rectangular plates with various thicknesses in comparison with the classical shell-based approach. In addition, the reliability of the approach has also been proved through an industrial example. an optical plastic lens, in comparison of real experiments.
- Published
- 2003
44. Application of Design of Experiments and Numerical Analysis to Optimal Design for Injection Molding Processes of Electrical Parts
- Author
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Jong-Ho Ahn, Sang-Ryun Choi, and Keun Park
- Subjects
Optimal design ,Engineering ,business.industry ,Mechanical Engineering ,Numerical analysis ,Design of experiments ,Molding (process) ,business ,Process engineering - Published
- 2002
45. Transconjunctival Suturing of Scleral Flap Using Illuminator in Eyes with Hypotony Following Trabeculectomy
- Author
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Yong Yeon Kim, Su Jin Park, Chungkwon Yoo, Jong Yeon Lee, Jong Ho Ahn, and Dong Heun Nam
- Subjects
medicine.medical_specialty ,business.industry ,Ophthalmology ,medicine.medical_treatment ,medicine ,Trabeculectomy ,business ,Scleral flap - Published
- 2017
46. Oven drying improves the nutritional value ofCalliandra calothyrsus andGliricidia sepium as supplements for sheep given low-quality straw
- Author
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B. W. Norton, Jong-Ho Ahn, and Robert Elliott
- Subjects
Calliandra ,Nutrition and Dietetics ,biology ,ved/biology ,ved/biology.organism_classification_rank.species ,Straw ,biology.organism_classification ,Gliricidia ,Rumen ,Animal science ,Fodder ,Botany ,Dry matter ,Calliandra calothyrsus ,Agronomy and Crop Science ,Gliricidia sepium ,Food Science ,Biotechnology - Abstract
Leaves from the tree legumes Gliricidia (Gliricidia sepium) and Calliandra (Calliandra calothyrsus) were fed as supplements (200 g dry matter) to sheep (n=3) given a basal diet of barley straw ad libitum. Tree leaves were fed either freshly harvested (F=fresh) or after drying at 60°C in a forced draught oven (D=dried). Voluntary intakes, digestibility and aspects of nitrogen (N) and phenolic compound metabolism were measured in all sheep. Drying decreased the condensed tannin (CT) content of Calliandra (F 117, D 82 g CT kg−1 DM). Total phenolics (TP) were significantly decreased when Gliricidia was dried (F 39, D 21 g TP kg−1 DM), and CT content was reduced from 20 g CT kg−1 DM to zero. Sheep given Gliricidia had higher rumen ammonia concentrations (73–85 mg N litre−1) than did sheep given Calliandra (37–40 mg N litre−1). For both species, drying significantly increased the voluntary consumption of straw, increased DM digestibility, decreased faecal N excretion and increased N balance. For calliandra, drying decreased the apparent degradability of N in the rumen (DNR) from 0·40 to 0·28 g N g−1 N ingested, and increased the apparent digestibility of N (ADN) in the post-ruminal tract from 0·20 to 0·52 g N absorbed g−1 N flowing into the small intestines. For Gliricidia, DNR decreased from 0·64 to 0·51 and ADN increased from 0·41 to 0·56. There were no significant effects of drying on rates of microbial N synthesis. The above changes were discussed in relation to changes in tannin content and it was concluded that drying facilitates the formation of protein–tannin complexes which protect proteins from degradation in the rumen. These proteins are subsequently released in the small intestines, thereby promoting an increased efficiency of dietary N utilisation. ©1997 SCI
- Published
- 1997
47. Thermal Ocular Surface Injury from Cooking Oil: Delayed Onset Transient Corneal Infiltration and Myopic Shift
- Author
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Jong Ho Ahn and Dong Hyun Kim
- Subjects
medicine.medical_specialty ,Intraocular pressure ,Visual acuity ,genetic structures ,medicine.medical_treatment ,Keratomileusis ,Corneal inflammation ,03 medical and health sciences ,0302 clinical medicine ,Ophthalmology ,Cornea ,Correspondence ,medicine ,Conductive keratoplasty ,Corneal Infiltration ,business.industry ,eye diseases ,Surgery ,Right conjunctival sac ,medicine.anatomical_structure ,030228 respiratory system ,030221 ophthalmology & optometry ,sense organs ,medicine.symptom ,business - Abstract
Dear Editor, Thermal ocular surface injury is common in daily life and presents as epithelial loss, localized edema, and neovascularization in the cornea. Most symptoms occur immediately after the injury and improve within 24 to 48 hours [1]. Transient myopic shift is mostly induced by drugs or blunt eye trauma. We present delayed onset transient anterior corneal infiltration and myopic shift after thermal ocular surface injury from hot cooking oil. A 27-year-old-man complained of ocular discomfort after hot cooking oil splashed in his right eye. He had undergone laser epithelial keratomileusis in both eyes 3 years previous. On examination, uncorrected visual acuity in both eyes was 20 / 20, and intraocular pressure was within the normal range. The pH in his right conjunctival sac was 7.0 after copious irrigation. Mild conjunctival injection and punctate corneal epithelial erosion in the right eye were observed in the slit lamp examination. Spherical equivalent was -1.125 Dsph in the right eye and -0.75 Dsph in the left eye. Mean keratometric (K) value was 40.00 diopters (D) in his right eye and 39.75 D in his left eye according to an auto refractive keratometer (ARK-510A; Nidek, Gamagori, Japan). After 2 days, he presented with decreased vision in the right eye. His uncorrected and corrected visual acuities in the right eye were 20 / 250 and 20 / 50, respectively. Slit lamp examination revealed diffuse anterior stromal infiltration and mild edema in his right cornea (Fig. 1A). There were no corneal epithelial defects or anterior chamber reaction in the right eye. Central corneal thickness using noncontact specular microscopy (SP-3000P; Topcon, Tokyo, Japan) was 548 µm in the right eye and 426 µm in the left eye. Spherical equivalent and mean K value in his right eye changed to -4.50 Dsph and 42.75 D, respectively. Localized inflammatory reaction associated with oil splashing thermal injury was suspected, and he was treated with topical prednisolone 1.0% combined with levofloxacin 0.5%, 8 times a day. In addition, 30 mg of systemic prednisolone was administered once a day and was tapered for 3 weeks. After 16 days, uncorrected visual acuity in the right eye returned to 20 / 20. Spherical equivalent was -0.75 Dsph, and mean K value was 40.00 D. Anterior stromal infiltration was completely resolved (Fig. 1B). Fig. 1 (A) Diffuse anterior stromal infiltrate appeared 2 days after thermal ocular surface injury due to cooking oil (yellow arrow). (B) Stromal infiltrate disappeared after topical and systemic steroid treatments (day 16). (C) The changes in spherical equivalent ... This is a first case report of delayed onset transient corneal infiltration and myopic shift after thermal ocular surface injury. Considering the onset of corneal infiltration, the cause of corneal infiltrate in this case appears to be delayed type hypersensitivity (DTH) reaction. DTH reaction takes 2 to 3 days to develop, and foreign materials act as haptens that conjugate with proteins, the complex of which combines with T lymphocytes, leading to an inflammatory response [1,2]. A previous study showed that oxidized cooking oil enhanced DTH in mice [3]. Further experimental study is needed to reveal the maturation of dendritic cells and to determine whether the DTH is triggered after cooking oil exposure. Transient myopic changes were mostly induced from sclera-choroidal inflammation or changes in the lens-iris diaphragm [4]. An increase in K value occurred during corneal inflammation in this case. When back-calculation was applied using the clinical history method, the change in K value was well matched with the change in refraction of the corneal plane (Fig. 1C) [5]. Corneal thermal injury may cause collagen shrinkage and induce a transient steepening in the central cornea, as in conductive keratoplasty. In conclusion, we described a rare case of delayed onset transient corneal infiltration and transient myopic shift following a cooking oil burn. Clinicians should keep in mind delayed corneal changes though no ocular abnormalities are observed immediately after thermal ocular surface injury related with cooking oil.
- Published
- 2016
48. A Case of Polymyositis in a Patient with Primary Biliary Cirrhosis Treated with D-Penicillamine
- Author
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Tae Hun Kim, Jong Ho Ahn, Kyong Ran Peck, and Yeong Wook Song
- Subjects
medicine.medical_specialty ,Pathology ,Case Report ,Gastroenterology ,Polymyositis ,Autoimmune Diseases ,Pathogenesis ,Primary biliary cirrhosis ,Internal medicine ,medicine ,Humans ,Liver Cirrhosis, Biliary ,business.industry ,D-penicillamine ,Penicillamine ,Clinical course ,Middle Aged ,Dermatomyositis ,medicine.disease ,Toxicity ,Female ,business ,medicine.drug - Abstract
Although D-penicillamine has been used for many rheumatologic diseases, toxicity limits its usefulness in many patients. Polymyositis/dermatomyositis can develop as one of the autoimmune complications of D-penicillamine treatment, but its exact pathogenesis remains unclear. We report a patient with primary biliary cirrhosis, who developed polymyositis while receiving D-penicillamine therapy. We described the special clinical course of the patient. Patients receiving D-penicillamine therapy should be followed carefully for the development of autoimmune complications like polymyositis/dermatomyositis.
- Published
- 1993
49. A case of tuberous sclerosis with pulmonary involvement
- Author
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Jong Ho Ahn, Gee Young Suh, Yong Chol Han, Young Soo Shim, Keun Youl Kim, and Young Whan Kim
- Subjects
Pulmonary and Respiratory Medicine ,Pathology ,medicine.medical_specialty ,Lung ,business.industry ,medicine.medical_treatment ,food and beverages ,Chylothorax ,medicine.disease ,Lesion ,Tuberous sclerosis ,Epilepsy ,Infectious Diseases ,medicine.anatomical_structure ,Pneumothorax ,Lymphangioleiomyomatosis ,medicine ,medicine.symptom ,business ,Pleurodesis - Abstract
Tuberous sclerosis is a syndrome characterized by the facial skin lesion, epilepsy, and mental retardation. Pulmonary involvement is uncommon, but when the lung is involved by tuberous sclerosis it shows characteristic reticulonodular infiltration and cystic changes. We experienced a 34-year-old female patient of known tuberous sclerosis admitted due to pneumothorax. Chest PA showed diffuse fine reticulonodular infiltration and chest CT revealed diffuse cystic changes of the lung. Pleurodesis with tetracycline was done to prevent recurrence, but chylothorax occurred four months after the treatment. Pleurosis was tried again and anti estrogen treatment began.
- Published
- 1992
50. Size distribution, sources, and seasonality of suspended particles in southern California marine bathing waters
- Author
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Jong Ho, Ahn and Stanley B, Grant
- Subjects
Quality Control ,Water Movements ,Animals ,Humans ,Baths ,Seawater ,Water Pollutants ,Public Health ,Seasons ,Particle Size ,Risk Assessment ,Swimming ,Environmental Monitoring - Abstract
In this paper we define seasonal and along-shore variations in suspended particle size distributions (PSDs) at two marine bathing beaches in southern California, using a low-angle light scattering instrument (LISST). Empirical Orthogonal Function (EOF) analysis of the LISST data set (n = 55 651) identified three particle size modes that collectively account for90% of the variance in the de-meaned PSD data at six sites along the shoreline at Huntington Beach and Newport Beach: a dinoflagellate mode, a large particle mode, and a small particle mode. These three modes exhibit distinct seasonal patterns, and along-shore distributions, reflecting both the sources of particles and environmental factors that trigger their occurrence. Comparison of volume-based PSDs generated from the LISST and from image analysis of optical micrographs indicates that the LISST performs well when measuring the size distribution of particles associated with dinoflagellate blooms. However, LISST measurements on stormwater-impacted samples consistently yield a rising tail at small particle sizes that may be an artifact arising from the non-spherical nature of inorganic particles in terrestrial runoff. The results presented here demonstrate that PSDs measured by light scattering instruments such as the LISST represent a new data resource for assessing water quality, and managing human health risk, at marine bathing beaches.
- Published
- 2007
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