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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Colloidal Processing of Non-Oxide Ceramic Powders in Aqueous Medium

Laarz, Eric January 2000 (has links)
No description available.
92

A Model to Measure Lymphatic Drainage from the Eye

Kim, Min Hui 12 December 2011 (has links)
Intraocular pressure (IOP) is the most important risk factor for glaucoma development and progression. Most anti-glaucoma treatments aim to lower IOP by enhancing aqueous humor drainage from the eye. Aqueous humor drainage occurs via well-characterized trabecular meshwork (TM) and uveoscleral (UVS) pathways, and the recently described ciliary lymphatics. The relative contribution of the lymphatic pathway to aqueous drainage is not known. We developed a sheep model to quantitatively assess lymphatic drainage along with TM and UVS outflows. Following intracameral injection of 125I-bovine serum albumin (BSA), lymph and blood samples were continuously collected. Lymphatic and TM drainage were quantitatively assessed by measuring 125I-BSA recovery. This quantitative sheep model enables assessment of relative contributions of lymphatic drainage (1.64% ± 0.89%), TM (68.86% ± 9.27%) and UVS outflows (19.87% ± 5.59%), and may help to better understand the effects of glaucoma agents on outflow pathways.
93

A Model to Measure Lymphatic Drainage from the Eye

Kim, Min Hui 12 December 2011 (has links)
Intraocular pressure (IOP) is the most important risk factor for glaucoma development and progression. Most anti-glaucoma treatments aim to lower IOP by enhancing aqueous humor drainage from the eye. Aqueous humor drainage occurs via well-characterized trabecular meshwork (TM) and uveoscleral (UVS) pathways, and the recently described ciliary lymphatics. The relative contribution of the lymphatic pathway to aqueous drainage is not known. We developed a sheep model to quantitatively assess lymphatic drainage along with TM and UVS outflows. Following intracameral injection of 125I-bovine serum albumin (BSA), lymph and blood samples were continuously collected. Lymphatic and TM drainage were quantitatively assessed by measuring 125I-BSA recovery. This quantitative sheep model enables assessment of relative contributions of lymphatic drainage (1.64% ± 0.89%), TM (68.86% ± 9.27%) and UVS outflows (19.87% ± 5.59%), and may help to better understand the effects of glaucoma agents on outflow pathways.
94

Use Of Triton X-114 Aqueous Two Phase System For Recovery Of Mushroom (agaricus Bisporus) Polyphenoloxidase

Besel, Elif 01 January 2003 (has links) (PDF)
Mushroom (Agaricus bisporus) polyphenoloxidase (PPO) (EC 1.14.18.1) was isolated and purified using an aqueous two phase system composed of octyl phenol (ethyleneglycol) 7-8 ether (Triton X-114/TX-114). TX-114 is a non-ionic surfactant which thermoseparates in water and forms an aqueous two phase system with a surfactant-depleted top phase and a surfactant-enriched bottom phase. Critical micelle concentration (CMC) and cloud point of the surfactant are 0.17 mM and 22&ordm / C respectively. The partitioning behavior of mushroom PPO in water/TX-114 aqueous two-phase systems was studied and the effects of TX-114 concentration, ionic strength, pH, temperature and crude extract preparation on PPO partitioning were studied. PPO generally partitioned to the surfactant-depleted top phase / whereas many other hydrophobic proteins and molecules partitioned to the surfactantenriched bottom phase. When two-step ultrafiltration was used as a pretreatment, complete enzyme recovery was achieved with all studied TX-114 concentrations. Moreover, about 5 fold purification was achieved by using 8% TX-114. The purification increased to 10 fold by using polyvinylpolypyrolidone (PVPP) at pH 7.0 with a recovery of 72%. However changing pH from 7.0 to 6.0 increased the purification factor and enzyme recovery to 15 fold and 100%, respectively. Addition of potassium or sodium salts caused PPO molecules to partition in the surfactantenriched bottom phase. Finally, crude enzyme can be concentrated besides being purified and recovered by doing aqueous two-phase separation at room temperature.
95

A study of aqueous extracts from roots and leaves of Pluchea indica (L.) Less. on cancer cell lines

Tsao, Shu-chuan 12 September 2007 (has links)
Pluchea indica (L.) Less. is a shrub of the family Compositae and is widespread along the western coast in Taiwan. Previous studies indicated that the components of Pluchea indica have potent anti-inflammatory, anti-ulcer and antimicrobial activities. In the present study, the effects of aqueous extract of roots and leaves from P. indica on the cancer cell lines were investigated. Various experimental approaches including cell growth curves, MTT assay, MTS assay, focus formation assay and cell migration assay were performed on the aqueous extract-treated cancer cells. Our results demonstrate the aqueous extract of P. indica induced anti-proliferation activity on GBM8401 and HeLa cancer cell lines.
96

Colloidal Processing of Non-Oxide Ceramic Powders in Aqueous Medium

Laarz, Eric January 2000 (has links)
No description available.
97

Coating studies and video imaging of the flow patterns of tablets in a semi-circular fluidized bed

Subramanian, Ganeshkumar A. January 2001 (has links)
Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xiv, 159 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 118-122).
98

Polar analyte effects on charge transport and trapping In organic field effect transistor based chemical and vapor sensors

Duarte, Davianne A. 22 June 2011 (has links)
Organic thin film transistors (TFTs) based on the field effect transistor architecture provide a methodology for sensing by exhibiting a change in the transport properties such as shifts in mobility, threshold voltage and conductivity. Chemical recognition is achievable by various methods including the two processes, which we are studying, direct analyte interactions with the semiconductor and specific receptor molecules on the semiconducting surface. Previous work demonstrates the effects of carrier concentration, grain size (surface morphology), and channel length on the sensing response to analytes such as alcohols, which exhibit a moderate dipole moment. When the alcohol interacts with the organic channel the addition of a trap and a positive charge occurs at the grain boundaries. At low carrier concentrations the added charge has the effect of producing an increase in current for the sensing response. At higher carrier concentrations the occurrence of trapping overwhelms the effect of the positive charge and you see and reduction in current. Typically the mobility shifts, which occur during sensing are correlated with trapping for polar analytes. The magnitude of the mobility decreases are dependent on the dipole moment of the polar analyte. Another aspect of organic materials is the fine-tuning of the chemical sensitivity by modifying the surface with receptor sites to increase the partition coefficient. In our study we pull the polarization, molecular dipole moment, transport and trapping, and partition coefficient concepts together to produce a model, which describes how an OFET based sensor interacts with an analyte with and without receptor molecules and under aqueous conditions. / text
99

Development of an Electrochemical Reactor for the Aqueous Phase Destruction of Chlorinated Hydrocarbons

Wang, Lei January 2008 (has links)
A cylindrical electrochemical reactor with a 3 in diameter copper or nickel metal foam cathode and a concentric carbon cloth anode was used to destroy aqueous phase carbon tetrachloride (CT). The results show that a high CT conversion can be achieved in regions of the cathode near the anode, but a low CT conversion is obtained in the region around the center of the cathode. This CT conversion distribution in the radial current-conducting direction suggests that a portion of the cathode worked inefficiently even though the overall CT conversion is still adequate. Further research by changing the solution pH and conductivity suggests that the radial conversion distribution is due to radial variations in cathode surface availability. The inherent difficulties that these results imply with regards to reactor scale up suggested a new approach to the design. An annular reactor, consisting of a thin (3.2 mm) nickel foam cathode wrapped around an inert Plexiglas core and separated for an external concentric anode by a semi-permeable membrane was adopted. Under compatible operating conditions, the annular reactor showed a high overall effluent CT conversion. However, experiments at low pH (2.25) yielded higher conversions than under neutral pH conditions. This result suggests that CT conversion is favored by a relatively high proton concentration. This reactor can be simulated by a one dimensional model. The annular reactor was used to destroy PCE and TCE successfully, which suggests that this technique can be employed to treat groundwater contaminated with complex mixtures of chlorinated hydrocarbons.A multi-layer reactor based on the principle of the annular reactor was developed as an option for the scale up of the system. This reactor exhibited high and uniform radial CT conversion.
100

Degradation of Vinyl Chloride and 1,2-Dichloroethane by Advanced Reduction Processes

Liu, Xu 16 December 2013 (has links)
A new treatment technology, called Advanced Reduction Process (ARP), was developed by combining UV irradiation with reducing reagents to produce highly reactive species that degrade contaminants rapidly. Vinyl chloride (VC) and 1,2-dichloroethane (1,2-DCA) pose threats to humans and the environment due to their high toxicity and carcinogenicity. In this study, batch experiments were conducted under anaerobic conditions to investigate the degradations of VC and 1,2-DCA with various ARP that combined UV with dithionite, sulfite, sulfide or ferrous iron. Complete degradation of both target compounds was achieved by all ARP and the reactions were found to follow pseudo-first-order decay kinetics. The effects of pH, sulfite dose, UV light intensity and initial contaminant concentration on the degradation kinetics were investigated in the photochemical degradation of VC and 1,2-DCA by the sulfite/UV ARP. The rate constants were generally promoted by raising the solution pH. The optimal pH conditions for VC and 1,2-DCA degradation were pH 9 and pH 11,respectively. Higher sulfite dose and light intensity were found to increase the rate constants linearly for both target contaminants. A near reciprocal relation between the rate constant and initial concentration of target compounds was observed in the degradation of 1,2-DCA. The rate constant was observed to be generally independent of VC concentration, but with a slight increase at lower concentrations. A degradation mechanism was proposed that described reactions between target contaminants and reactive species such as the sulfite radical and hydrated electron that were produced in the photolysis of sulfite solution. A mechanistic model that described major reactions in the ARP system was developed and explained the dependence of the rate constant on those experimental factors. Chloride ion and chloroethane were detected as the major degradation products at acid and neutral pH. An increase in pH promoted the extent of dechlorination with complete dechlorination being observed at pH 11 for both VC and 1,2-DCA. Due to the rapid degradation kinetics in these ARPs, this new treatment technology may be applied to remove various contaminants in water and wastewater.

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