No description available.

The problem was to study the behavior of several hydrocarbons when they were subjected to ultraviolet light of 2536 Å in the presence of mercury vapor.

Microbial Reduction on Eggshell Surfaces by the use of Hydrogen Peroxide and Ultraviolet Light. (August 2011) Steven Michael Gottselig, B.S., Texas A&M University Chair of Advisory Committee: Dr. Craig Coufal The effect of hydrogen peroxide (H2O2) in combination with ultraviolet light (UV) as an egg sanitization process on eggshell surfaces was studied. Preliminary experiments were conducted to develop an optimized methodology for eggshell disinfection that will be an effective and efficient way to reduce microorganisms on hatching eggs. Several experiments were conducted to reduce the natural flora found on the eggshell surface. Hatching eggs were collected from White Leghorn hens housed in floor pens with nest boxes. Eggs had no adhering organic material present. Results from these experiments led to the modification of the prototype equipment as well as the treatment application methodology. Following the experiments to optimize the methodology for H2O2 spraying and UV exposure time, the methodology was applied to eggs inoculated with Salmonella Typhimurium. Eggshell crush and rub methodology was used to enumerate bacteria within the pores and membranes of the egg. The optimized H2O2 and UV combination treatment process was then applied to commercial broiler breeder hatching eggs to evaluate the effects on hatchability. Based on the parameters tested, results indicate that two applications of 3% H2O2 followed by 5 sec of UV exposure after each application produced the most consistent microbial reductions on eggshells. To enhance these effects, the addition of a 180° rotation between the two applications showed to be effective at further reducing the natural flora found on the eggshell surface. Studies using this optimal methodology on eggs inoculated with Salmonella at 9 log10 CFU/egg yielded greater than 5 log10 CFU/egg reductions. However, this methodology had little to no effect on reducing bacteria found within the pores and membranes of the eggs inoculated with Salmonella. These findings indicate that the effects of the disinfection process are largely limited to the eggshell surface. Hatch studies showed significant reductions in eggshell microbial levels under field conditions with eggs having large amounts of organic material present on the shell surface. Hatchability was maintained after treatment when compared to untreated eggs. Additional studies are needed to develop advanced equipment to apply this technology under commercial conditions.

Perchlorate is one of the major emerging contaminants of concern and has been found in soil and water systems throughout the United States. Human exposures to perchlorate could occur by ingestion of contaminated water and food as well as by skin contact. Studies show that perchlorate blocks the sodium iodide symporter (NIS) protein in human body, which results in several diseases. It has been demonstrated that perchlorate can be removed by Advanced Reduction Processes (ARPs) that combine chemical reductants (e.g. sulfite) with activating methods (e.g. UV light) in order to produce highly reactive reducing free radicals that are capable of rapid and effective perchlorate reduction. However, other compounds in a real system might inhibit or promote this reduction process. Natural organic matter (NOM) widely exists in the environment and it can absorb UV light, so it has the potential to influence the process of perchlorate reduction by ARPs that use UV light as the activating method. Therefore, batch experiments were conducted to obtain data on the impacts of natural organic matter and light intensity on destruction of perchlorate by the ARPs that use sulfite activated by ultraviolet light produced by low-pressure mercury lamps or KrCl excimer lamps. The results indicate that NOM strongly inhibits perchlorate removal by either the sulfite/UV-KrCl or the sulfite/UV-L ARP, because NOM competes with sulfite for UV light and can possibly scavenge sulfite radicals. Even though the absorbance of sulfite is much higher at UV wavelength of 222 nm than that at 254 nm, the results indicate that a higher portion of perchlorate was removed with the UV-L lamp than with the UV-KrCl lamp. The results of this study will help to develop the proper way to apply the ARPs in a real wastewater treatment plant.

Two studies investigating the use ultraviolet light at a wavelength of 253.7nm (UVC) into the inhibition of Salmonella spp. and Escherichia coli O157:H7 were conducted. The objectives of these studies were: to determine the rates for the destruction of Salmonella and Escherichia coli O157:H7 on the surface of agar and to investigate its effectiveness on the surface of fresh produce. Multiple replications of different doses and cocktail concentrations were performed and resulted in a 5 log reduction of Escherichia coli O157:H7 at doses exceeding 8.4 mW / cm2, while a 5 log reduction for Salmonella spp. was observed at doses exceeding 14.5 mW / cm². Samples of Red Delicious apples, green leaf lettuce and tomatoes were subjected to different doses ranging from 1.5 __ 24 mW / cm2 of UVC to determine effective log reductions of microbial populations. UVC applied to apples inoculated with E. coli O157:H7 resulted in the highest log reductions of approximately 3.3 logs at 24 mW/cm2. Lower log reductions (2.19 logs) were seen on tomatoes inoculated with Salmonella spp. and leaf lettuce (2.65 and 2.79) inoculated with both Salmonella spp. and E. coli O157:H7 respectfully. Due to the low capital involved in initiating a UVC system, the use of ultraviolet energy may prove to be a beneficial mechanism to decrease pathogens on fresh produce if used in conjunction with strict adherence to a sanitation program, Good Manufacturing Practices and Good Agricultural Practices in ensuring the safety of fresh produce. / Master of Science

The problem was to study several hydrocarbons when they were subjected to ultraviolet light of 2536 Å in the presence of mercury vapor. It would be expected from the work of Stallings that the rupture of any tertiary hydrogen bond in the molecule would be the predominant effect. However, secondary and primary bond splitting would occur as well as some C-C bond rupturing, but these could be expected to a lesser degree than the first, since the t-hydrogen has the greatest reactivity.

Mast cells (MCs) play a central role in inflammation by releasing mediators following activation. S100A8 and S100A9 are abundantly expressed in inflammatory sites such as asthmatic lung, sunburnt skin and atherosclerosis where MCs are involved in pathogenesis; roles of S100A8 in MC function are undetermined. The aims of this thesis were to determine effects of S100A8 on MC activation, particularly provoked by IgE and UVB. Initially, effects of UVB on MC activation were investigated as detailed functions were unclear. Cord blood-derived human mast cells (CBMCs) were treated in vitro with varying doses of UVB and production of multiple cytokines and viability investigated. UVB exposure selectively increased levels of IL-8 (CXCL8), and to a less extent IL-1β, but not eight other cytokines tested. New protein synthesis partially contributed and IL-8 production was p38 MAPK-dependent. UVB dose-dependently induced MC apoptosis indicating a potential regulatory mechanism of MC function. The ability of recombinant S100A8, S100A9 or S100A8/9 heterodimer to modulate IgE/antigen (DNP/anti-DNP)-mediated activation of a murine MC line, and of bone marrow-derived (mBM) MC activation was determined. The S100s did not directly induce degranulation or induce IL-6. S100A8 significantly inhibited DNP/anti-DNP-provoked degranulation, and IL-6 and TNF mRNA and protein induction. S100A8 did not alter FcεRIα expression. S100A9 was less effective; and the S100A8/9 complex was also suppressive. S100A8 only weakly suppressed non-specific MC degranulation. Mutation of Cys41 in S100A8 negated its suppressive activity. Because S100A8 scavenges oxidants via this reactive Cys residue, we propose that this may mediate its ability to downmodulate IgE-dependent MC responses. Similar to the thiol scavenger N-acetyl-L-cysteine, S100A8 but not the Ala41 mutant, attenuated DNP/anti-DNP-provoked LAT phosphorylation. However, the disulfide-bonded S100A8 dimer and S100A8 containing a sulfinamide bond between Cys41 and Lys34/35 also reduced MC activation, indicating an additional pathway(s). S100A8 did not suppress antigen/IgE-induced responses of CBMC possibly because these may not truly reflect fullymature human tissue MCs. S100A8 did not alter UVB-induced IL-8 release by CBMCs, or affect apoptosis. Murine S100A8 may have anti-inflammatory properties by regulating MC activation in an activator-specific manner, at least partially by scavenging ROS to suppress intracellular signalling.

Currently in Taiwan¡¦s textile-dying industry, sodium hypochlorite (NaOCl) is popularly used as a decolorization oxidant. In order to surely meet the effluent color regulation of 550 ADMI (American Dye Manufactures Institute), excessive dosage of sodium hyperchlorite is commonly used, which results in the increase of residual chloride and the accumulation of toxic chlorinated compound in the environment. This study probes into the characteristics of substitute oxidant for sodium hypochlorite to avoid the production of toxic products. The study includes decolorization efficiency evaluation, economical analysis and feasibility of commercial application. This study adopts ozone as an oxidant and ultraviolet light as the oxidant enhancer for the purpose of preventing the occurrence of secondary pollution products like trihalomethane from the sodium hyperchlorite application. Literature review indicates that there are several studies for reaction mechanisms of oxidation and disinfection of ozone and ultraviolet light for decolorization and the conclusions reveal much promising results. There are three topics in this study, which are: Topic 1: Feasibility study. This study focuses on whether the effluent color concentration of the treatment process meets the color effluent standard or not. A 3.5 L volume reactor was used in this section. Topic 2: Influencing factor analysis. A 14 L volume reactor was adopted for analyzing the influencing factors for decolorization and for comparing the differences in treatment efficiencies between a dye finishing plant effluent and two commercial dyestuff samples. Topic 3: Economic analysis. The analysis focuses on economic comparison between NaOCl and UV/Ozone processes for effluent decolorization. Analysis results of the investment cost, operation/maintenance expense, and investment return duration are presented in this section. A 50 L volume reactor was used to achieve the evaluation for this part. First topic of this study examined some operating parameters for treating effluent from the biological and chemical coagulation units of a dye-finishing wastewater treatment plant using the UV/Ozone technique to meet an effluent regulation of 550 ADMI values could be reduced from approximately 4,000 to 200 ADMI in an hour using the UV/Ozone technique. The results show that higher color removal efficiency could be achieved at pH values around 3 as compared with higher pH values of around 7 and 10. This might be due to the fact that the predominant ozone molecules at lower pH values are more selective to certain chromophore molecules in wastewater, despite the fact that hydroxyl radicals are predominant at higher pH values and have a stronger oxidation capability than ozone. The UV light used in this study emitted from the experimental lamp can excite oxygen and water molecules to produce ozone molecules and hydroxyl radicals that can then increase decolorization rate. The findings of this investigation reveal that the proposed UV/Ozone treatment scheme has potential for development into an environmentally friendly decolorization approach for dye finishing wastewater treatment. The second topic is to investigate the feasibility of applying UV/Ozone techniques to reduce color content caused by two commercial reactive dyes (Orange-13 and Blue-19). Bench experiments were performed using a 14-L reactor. Controlling factors including pH value, dosage of ozone, reaction time, and UV intensity were evaluated to obtain the optimal operating parameters. Results from this study show that the ozone dosage and pH value dominated the effects on the decolorization process. However, UV intensity shows relatively insignificant effects. Results also indicate that the color content could be reduced from 2,000 to 200 ADMI within a reaction time of 30 minutes with a total ozone dosage of 100 mg/L. This study shows that pH values of approximately 3 and 10 favored the decolorization of the studied Dye Blue-19 and Orange-13, respectively. This was due to the effects that molecular ozone and hydroxyl radicals had significant oxidative power at low and high pH, respectively. Moreover, molecular ozone was more selective to certain dye structures during its oxidation process. This also caused the effect that pH value played an important role on color removal. Kinetic analyses show that the decolorization reactions of Dye Orange-13 and Blue-19 followed a first-order decolorization model. Experimental results also indicate that the degree of decolorization was primarily proportional to the ozone dosage. Results from this study provide us an insight into the characteristics and mechanisms of decolorization by UV/ozone technique. Results will also aid in designing a system for field application of dye finishing plants. According to the results from the third topic, for a dye finishing plant of wastewater flow rate of 800CMD (m3/day), the capital cost of equipment and related establishment as well as amendment is about US$ 116,300, and the monthly operation and maintenance cost is US$ 4,030. In this study, ozone was used as a substitute decolorizing oxidant to treat the effluent from the secondary biological and physical/chemical treatment plant. Because the current cost for the decolorization oxidant (NaOCl) is approximately US$ 5,700 per month, the monthly saving, adopting the decolorization system using UZ/Ozone, will be US$ 1,670. The investment return period will be over 7 years and is not attractive to the plant owners. However, to prevent the accumulated toxicity of chloride compounds in the environment and to promote the desires of investment on the advanced decolorization technique, a favorable tax deduction policy needs to be applied.

No description available.

Mast cells (MCs) play a central role in inflammation by releasing mediators following activation. S100A8 and S100A9 are abundantly expressed in inflammatory sites such as asthmatic lung, sunburnt skin and atherosclerosis where MCs are involved in pathogenesis; roles of S100A8 in MC function are undetermined. The aims of this thesis were to determine effects of S100A8 on MC activation, particularly provoked by IgE and UVB. Initially, effects of UVB on MC activation were investigated as detailed functions were unclear. Cord blood-derived human mast cells (CBMCs) were treated in vitro with varying doses of UVB and production of multiple cytokines and viability investigated. UVB exposure selectively increased levels of IL-8 (CXCL8), and to a less extent IL-1β, but not eight other cytokines tested. New protein synthesis partially contributed and IL-8 production was p38 MAPK-dependent. UVB dose-dependently induced MC apoptosis indicating a potential regulatory mechanism of MC function. The ability of recombinant S100A8, S100A9 or S100A8/9 heterodimer to modulate IgE/antigen (DNP/anti-DNP)-mediated activation of a murine MC line, and of bone marrow-derived (mBM) MC activation was determined. The S100s did not directly induce degranulation or induce IL-6. S100A8 significantly inhibited DNP/anti-DNP-provoked degranulation, and IL-6 and TNF mRNA and protein induction. S100A8 did not alter FcεRIα expression. S100A9 was less effective; and the S100A8/9 complex was also suppressive. S100A8 only weakly suppressed non-specific MC degranulation. Mutation of Cys41 in S100A8 negated its suppressive activity. Because S100A8 scavenges oxidants via this reactive Cys residue, we propose that this may mediate its ability to downmodulate IgE-dependent MC responses. Similar to the thiol scavenger N-acetyl-L-cysteine, S100A8 but not the Ala41 mutant, attenuated DNP/anti-DNP-provoked LAT phosphorylation. However, the disulfide-bonded S100A8 dimer and S100A8 containing a sulfinamide bond between Cys41 and Lys34/35 also reduced MC activation, indicating an additional pathway(s). S100A8 did not suppress antigen/IgE-induced responses of CBMC possibly because these may not truly reflect fullymature human tissue MCs. S100A8 did not alter UVB-induced IL-8 release by CBMCs, or affect apoptosis. Murine S100A8 may have anti-inflammatory properties by regulating MC activation in an activator-specific manner, at least partially by scavenging ROS to suppress intracellular signalling.