Biomedical subjects

K W Bang

Publications and source records attributed to K W Bang.

5 recordsLinked to original sources

PubMed2006

The hydrodynamic filter separator for removal of urban storm runoff.

The majority of storm runoff pollution is trapped in particles smaller than 100 microm in diameter. Solid particles smaller than 100 microm in diameter are not easily separated by conventional types of hydrodynamic separator, and remain in suspension in overflow. To overcome this problem, a HDFS (hydrodynamic filter separator) has been developed for treatment of the microparticles in urban storm runoff. We conducted a laboratory scale study on treatable potential of microparticles using HDFS that combined HDS with perlite filter. To determine the efficiency for various operation conditions, a series of experiments was performed with different solids concentrations and surface loading rate. The operation ranges of surface loading rates were 100 to 2,800 m3/m2/day, and influent solids concentrations were varied from 800 to 1,900 mg/L. Also, the particle size distribution was monitored to investigate the effects of surface loading rates on the particle size. Results indicated that the HDFS-inside type showed greater efficiency at solids separation than the other type.

Aluminum Oxide↗

PubMed2003

Evaluation of the methods for first flush analysis in urban watersheds.

The general tendency between the ratio of cumulative pollutant loads and the ratio of cumulative runoff appears as a nonlinear form which can be expressed in the form of a third polynomial. In this paper third degree polynomials were applied to represent the first flush curves based on the relationship between the cumulative pollutant load ratio and cumulative runoff ratio. The quantity of stormwater runoff and quality constituents, including chemical oxygen demand (COD), suspended solids (SS), total Kjeldahl nitrogen (TKN), ortho-phosphorus (PO4-P), total phosphorus (TP), n-hexane extracts (HEM), and iron (Fe) were analysed. The objectives of this study were (1) to characterize the quality of stormwater runoff (2) in order to analyse the cumulative curve area ratio and to calculate the first flush coefficients, (3) while also representing the first flush with a third polynomial equation.

Environmental Monitoring↗

PubMed2002

First flush analysis of urban storm runoff.

Stormwater runoff was monitored on 13 separate urban watersheds, which were chosen to represent distinct types of residential and industrial development, along with various watershed characteristics. A total of 38 storm events were monitored to investigate the first flush phenomenon. The first flush phenomenon may be defined as the initial period of stormwater runoff during which the concentration of pollutants is substantially higher than during later stages. The magnitude of the first flush phenomenon, and if it actually occurs, was calculated using a method of data analysis which results in determining the 'event mean concentration' (EMC). The magnitude of the first flush phenomenon was found to be greater for some pollutants (e.g. suspended solids from residential areas) and less for others (e.g. chemical oxygen demand from industrial areas). No correlation was observed between the first flush phenomenon and the antecedent dry weather period, however, the first flush phenomenon was greater for smaller watershed areas.

Cities↗

PubMed2002

Characterization of surface runoff in urban areas.

Water quality measurements of surface runoff have been carried out in selected residential and industrial zones in urban areas, in which yearly mean precipitation is 1,225 mm. The concentrations of constituents in the surface runoff were measured at sampling sites categorized by land use type in the residential zone, and by industry type in the industrial zone. The water quality constituents of BOD5, COD, SS, NO3-N, TKN, PO4-P, TP, n-Hexane extracts, Cr, Cu, Pb and Fe were analyzed. The event mean concentrations (EMCs) of COD, SS, TKN and TP in the residential zone were 313 mg/L, 279 mg/L, 8.45 mg/L, 1.98 mg/L, and those in the industrial zone were 80 mg/L, 106 mg/L, 5.07 mg/L, and 1.93 mg/L, respectively. Cumulative load curves were created to analyze the first-flushing effect of each pollutant related to the pollutant, the rainfall event, and the land use type. No general relationship between the cumulative load and runoff has been established. The degree of first-flushing effect by constituents was in the following order; TKN>COD>SS>HEM>TP>PO4-P. The correlations between SS and other constituents were analyzed to evaluate the efficiency of the physical treatment process to control the surface runoff in urban areas. Based on the correlation of constituents with SS, high treatment efficiency of SS, heavy metals, organic matter, and TP was expected. The unit pollutant loading rates of COD, SS, TKN, TP, Cr and Pb in the residential zone were 2,392, 2,130, 64.6, 15.1, 0.31, and 1.83 kg/ha/yr, and those in the industrial zone were 612, 812, 38.7, 14.8, 0.51 and 0.82 kg/ha/yr, respectively.

Cities↗

PubMed2000

Unique processing pathways within recipient antigen-presenting cells determine IgG immunity against donor platelet MHC antigens.

Recipient IgG immunity against leukoreduced donor platelets is dependent on indirect T-cell allorecognition and is suppressed in vivo by inhibitors (aminoguanidine, AMG) of inducible nitric oxide synthase (iNOS). To examine recipient processing pathways of donor platelet antigens, enriched macrophages (antigen-presenting cells [APC]) from BALB/c (H-2(d)) mice were pulsed with allogeneic C57BL/6 (H-2(b)) platelets and transfused weekly into naive BALB/c mice. Platelet-pulsed APC stimulated IgG antidonor antibody production in 45% of recipients by the second transfusion and in 100% by the sixth transfusion; this response was enhanced by pulsing in the presence of interferon-gamma. By the sixth transfusion, high-titer IgG1 (mean titer 4990) and IgG2a (1933) isotypes specific for donor major histocompatibility complex (MHC) class I antigens were detected. Platelet pulsing in the presence of AMG or colchicine significantly inhibited the ability of APC to stimulate IgG alloantibodies; only 50% (P <.005) and 20% (P <.0001) of recipients, respectively, produced antibodies by the sixth transfusion. AMG inhibition was reversed by the addition of L-arginine, the substrate for iNOS. In contrast, pulsing in the presence of chloroquine, the proteasome inhibitory peptide MG115, or Brefeldin A enhanced APC immunity (70-100% of recipients antibody positive by the second transfusion [P <.05]); these agents allowed the pulsed APC to stimulate IgG2a but inhibited IgG1 production and this correlated with a reduction in serum interleukin (IL)-4 levels. The results suggest that for donor platelet antigens to stimulate IgG alloantibodies, recipient APC use the essential generation of nitric oxide and a noncytosolic, pH-independent processing pathway, which can be exploited as an effective immunotherapy target to further inhibit alloimmunization against leukoreduced platelets. (Blood. 2000;95:1735-1742)

Ammonium Chloride↗