94 research outputs found
Use of Pollutant Load Regression Models with Various Sampling Frequencies for Annual Load Estimation
Water quality data are collected by various sampling frequencies, and the data may not be collected at a high frequency nor over the range of streamflow conditions. Therefore, regression models are used to estimate pollutant data for days on which water quality data were not measured. Pollutant load regression models were evaluated with six sampling frequencies for daily nitrogen, phosphorus, and sediment data. Annual pollutant load estimates exhibited various behaviors by sampling frequency and also by the regression model used. Several distinct sampling frequency features were observed in the study. The first was that more frequent sampling did not necessarily lead to more accurate and precise annual pollutant load estimates. The second was that use of water quality data collected from storm events improved both accuracy and precision in annual pollutant load estimates for all water quality parameters. The third was that the pollutant regression model automatically selected by LOADEST did not necessarily lead to more accurate and precise annual pollutant load estimates. The fourth was that pollutant regression models displayed different behaviors for different water quality parameters in annual pollutant load estimation
Designing an L-THIA Model for ArcGIS 10.2 Using Python 2.7
L-THIA (Long-Term Hydrologic Impact Analysis) is a mature model available as a spreadsheet, a web-based spatial model and as an add-in to the popular geographic information system (GIS) software system ArcGIS 10. The model generally has a method to determine an area of analysis such as a watershed, and then populates the watershed with data on soil and landuse. The model generally requires precipitation data for a long term and uses assumptions about the relationship between landuse, soil, and the chemistry of surface runoff passing across the various landscapes. Input data are landuse and soil map layers and long-term precipitatio
Development of Web GIS-Based VFSMOD System with Three Modules for Effective Vegetative Filter Strip Design
In recent years, Non-Point Source Pollution has been rising as a significant environmental issue. The sediment-laden water problem is causing serious impacts on river ecosystems not only in South Korea but also in most countries. The vegetative filter strip (VFS) has been thought to be one of the most effective methods to reduce the transport of sediment to down-gradient area. However, the effective width of the VFS first needs to be determined before VFS installation in the field. To provide an easy-to-use interface with a scientific VFS modeling engine, the Web GIS-based VFSMOD system was developed in this study. The Web GIS-based VFSMOD uses the UH and VFSM executable programs from the VFSMOD-w model as core engines to simulate rainfall-runoff and sediment trapping. To provide soil information for a point of interest, the Google Map interface to the MapServer soil database system was developed using the Google Map API, Javascript, Perl/CGI, and Oracle DB programming. Three modules of the Web GIS-based VFSMOD system were developed for various VFS designs under single storm, multiple storm, and long-term period scenarios. These modules in the Web GIS-based VFSMOD system were applied to the study watershed in South Korea and these were proven as efficient tools for the VFS design for various purposes
Development of Web GIS-Based VFSMOD System with Three Modules for Effective Vegetative Filter Strip Design
In recent years, Non-Point Source Pollution has been rising as a significant environmental issue. The sediment-laden water problem is causing serious impacts on river ecosystems not only in South Korea but also in most countries. The vegetative filter strip (VFS) has been thought to be one of the most effective methods to reduce the transport of sediment to down-gradient area. However, the effective width of the VFS first needs to be determined before VFS installation in the field. To provide an easy-to-use interface with a scientific VFS modeling engine, the Web GIS-based VFSMOD system was developed in this study. The Web GIS-based VFSMOD uses the UH and VFSM executable programs from the VFSMOD-w model as core engines to simulate rainfall-runoff and sediment trapping. To provide soil information for a point of interest, the Google Map interface to the MapServer soil database system was developed using the Google Map API, Javascript, Perl/CGI, and Oracle DB programming. Three modules of the Web GIS-based VFSMOD system were developed for various VFS designs under single storm, multiple storm, and long-term period scenarios. These modules in the Web GIS-based VFSMOD system were applied to the study watershed in South Korea and these were proven as efficient tools for the VFS design for various purposes
Erectile dysfunction and angiographic correlation between coronary artery stenosis and internal iliac-internal pudendal artery stenosis in patients with suspected coronary artery disease: a retrospective study
This study aimed to assess the angiographic correlation between coronary artery
stenosis and internal iliac-internal pudendal artery (II-IPA) stenosis and
evaluate its association with erectile dysfunction (ED). We reviewed the data of
91 patients who had undergone pelvic angiography (PA) to evaluate II-IPA stenosis
and coronary angiography (CAG) due to suspected coronary artery disease. Erectile
function (EF) was evaluated using the International Index of Erectile Function
before CAG and PA. CAG was performed first, followed by PA of the bilateral
II-IPA. Regardless of the location and number of stenosis sites, based on CAG, we
categorized the patients into two groups. Patients with a maximum stenosis
<50% and ≥50% on CAG were assigned to Group I and Group II,
respectively. Then, the EF domain score and the diameter stenosis (DS) of II-IPA
were evaluated and compared. Overall, 55 patients comprised Group I, while 36
patients comprised Group II. ED was present in 96.3% and 97.2% of the patients
in Group I and II, respectively. There was no statistical difference between the
groups in the severity of ED (p = 0.457). PA revealed that 14.5% and
36.1% of patients in Groups I and II had ≥50% stenosis of the II-IPA.
The mean DS of II-IPA in Group II was greater than that in Group I (p =
0.017). There was a statistically significant correlation between the degree of
coronary artery stenosis and the degree of II-IPA stenosis (r = 0.295, p = 0.005). This study revealed that coronary artery stenosis correlates with
II-IPA stenosis. The presence and degree of coronary artery stenosis or II-IPA
stenosis indicate the necessity for more active treatment in patients with ED
Modulation of Skin Collagen Metabolism in Aged and Photoaged Human Skin In Vivo
To the best of our knowledge, no study has been conducted to date to directly compare the collagen metabolism of photoaged and naturally aged human skin. In this study, we compared collagen synthesis, matrix metalloproteinase-1 levels, and gelatinase activity of sun-exposed and sun-protected skin of both young and old subjects. Using northern blot analysis, immunohistochemical stain, and Western blot analysis, we demonstrated that the levels of procollagen type I mRNA and protein in photoaged and naturally aged human skin in vivo are significantly lower than those of young skin. Furthermore, we demonstrated, by northern blot analysis, that the procollagen α1(I) mRNA expression of photoaged skin is much greater than that of sun-protected skin in the same individual. In situ hybridization and immunohistochemical stain were used to show that the expression of type I procollagen mRNA and protein in the fibroblasts of photoaged skin is greater than for naturally aged skin. In addition, it was found, by Western blot analysis using protein extracted from the dermal tissues, that the level of procollagen type I protein in photoaged skin is lower than that of naturally aged skin. The level of matrix metalloproteinase-1 protein and the activity of matrix metalloproteinase-2 were higher in the dermis of photoaged skin than in naturally aged skin. Our results suggest that the natural aging process decreases collagen synthesis and increases the expression of matrix metalloproteinases, whereas photoaging results in an increase of collagen synthesis and greater matrix metalloproteinase expression in human skin in vivo. Thus, the balance between collagen synthesis and degradation leading to collagen deficiency is different in photoaged and naturally aged skin
Regulation of endothelial cell and endothelial progenitor cell survival and vasculogenesis by integrin-linked kinase
OBJECTIVE: New vessel formation is a dynamic process of attachment, detachment, and reattachment of endothelial cells (ECs) and endothelial progenitor cells (EPCs) with each other and with the extracellular matrix (ECM). Integrin-linked kinase (ILK) plays a pivotal role in ECM-mediated signaling. Therefore, we investigated the role of ILK in ECs and EPCs during neovascularization. METHODS AND RESULTS: In human umbilical cord vein ECs and EPCs, endogenous ILK expression, along with subsequent cell survival signals phospho-Akt and phospho-glycogen synthase kinase 3beta, was reduced after anchorage or nutrient deprivation. Even brief anchorage deprivation resulted in retarded capillary tube formation by ECs. Adenoviral ILK gene transfer in ECs and EPCs reversed the decrease in cell survival signals after anchorage or nutrient deprivation, leading to enhanced survival, reduced apoptosis, and significantly accelerated the functional recovery after reattachment. And ILK overexpressing EPCs significantly improved blood flow recovery and prevented limb loss in nude mice hindlimb ischemia model. Furthermore, the efficacy of systemic delivery was equivalent to local injection of ILK-EPCs. CONCLUSIONS: ILK overexpression protects ECs and EPCs from anchorage- or nutrient-deprived stress and enhances neovascularization, suggesting that ILK is an optimal target gene for genetically modified cell-based therapy. Neovascularization is a dynamic process of detachment and reattachment of ECs and EPCs. Endogenous ILK expression was decreased in various stress conditions, and the gene transfer of ILK protected ECs and EPCs from temporary anchorage or nutrient deprivation. Furthermore, ILK gene transfer in EPCs significantly enhanced neovascularization in vivo
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