Recent advancements in molecular biology such as next generation sequencing and more sensitive and rapid molecular detection methods like qPCR, have historically been developed for clinical applications in human genetics and for health care diagnostic purposes. The high demand for faster and more accurate molecular assays in the health care field has driven rapid development of inexpensive molecular techniques that when applied to the science of environmental microbiology, provides an unprecedented level of understanding of the microbial world around us. The goal of this dissertation is to begin to apply more advanced molecular technologies to problems in applied environmental microbiology. Appendix A is a brief literature review of next generation sequencing technologies for applications in environmental microbiology. Appendix B focuses on the development of a more robust virus nucleic extraction kit for the detection of viral genomes from environmental samples found to contain high concentrations of qPCR inhibitors, such as humic acids or heavy metals. Appendix C summarizes one of the largest virus surveys done in the US, using state of the art qPCR technologies in both wastewater influent and effluent from two wastewater treatment plants in the Southwest. Data suggests that traditional virus indicators may not be a viable tool to evaluate fecally impacted source water or virus removal during water treatment. The third study summarized in Appendix D, provides one of the first insights into the microbial ecology of biofilms utilized as biological treatment media using Roche 454 amplicon sequencing of the 16S rRNA gene.

All possible convex hull (i.e. the minimum area convex polygon containing the planar set) algorithms ever published in scientific press have been analysed in this work. Two new convex hull algorithms created by myself have been presented. The running time of analysed algorithms has been surveyed. Three most popular algorithms (Graham Scan, Jarvis March and Quickhull), the oldest algorithm (Brute Force) as well as the both new ones have been implemented. Efficiency experiments have been carried out with them. The algorithms created by me achieved the best results. In order to raise the efficiency of all the algorithms I suggested a priori filtration of points, which decreases the amount of the original points by almost 50% and, consequently, the speed of algorithms is increased. The major part of this master work will be published in the magazine “Technological and economic development of economy”. Besides, the report of this work has been made in the conference of Lithuanian young scientists, called “Operation analysis and application”.

It is the first time in Lithuania that practical application of semen filtration by Sephadex G-15 for the needs of artificial insemination industry was assessed. The efficacy of semen filtration was assessed applying a battery of sperm quality assays to study bovine spermatozoa quality before and after filtration, as well as after cryopreservation. The estimation of effect of different concentrations of progesterone, oestradiol, heparin separately or in combination, on different functional parameters of bull spermatozoa after thawing was performed. These are the first published studies applying integrated approach to study the effects of sperm challenge with several biologically active substances.

Stringent water quality regulations and general aesthetic issues have urged drinking water industry to apply advanced water treatment technologies that can meet multiple treatment objectives. Removal of significant amount of natural organic matter (NOM), including colour causing organics, to meet stringent disinfection by product (DBP) regulations from source water with low alkalinity and low turbidity is very challenging with conventional water treatment processes. Membrane filtration processes are effective in removing significant amount of NOM thus minimizing the formation of carcinogenic DBPs. However, fouling of membrane is a major problem affecting system performance. Improved pretreatment of feed water helps reduce or eliminate membrane fouling. This study characterized source water, examined fouling in nanofiltration (NF) membranes and explored various pretreatment options to reduce NF fouling. Resin fractionation was performed to characterize NOM and to identify the major fractions responsible for DBP formation in natural source water of the Tatamagouche water treatment plant (WTP) in Nova Scotia. The source water primarily comprised of hydrophilic neutrals (HIN) and hydrophobic acid (HOA) compounds, with the latter being a major contributor to the DBP formation. Fouling behaviour of the NF membranes was examined at bench- and full-scale levels to understand the impact of source water quality on membrane fouling in the Tatamagouche and Collins Park WTPs. Bench- and full-scale results revealed higher fouling in the Collins Park WTP which together supported ongoing membrane cleaning practices in the plant. Surface enhanced Raman spectroscopy (SERS), demonstrated here as a novel technique, suggested that carbohydrates and proteins are the main foulants in the source water. Bench-scale experiments conducted to evaluate the performance of ozone (O3), ultraviolet (UV), hydrogen peroxide plus ozone (H2O2/O3), H2O2 plus UV (H2O2/UV) and O3 plus UV (O3/UV) for reducing NOM and DBP precursors suggested that the O3/UV AOP offers the optimum reduction of NOM. Integrating AOP pretreatments with NF membrane resulted in an improved permeate flux but not permeate quality of the NF membrane.

Water utilities in Nova Scotia face numerous challenges treating low turbidity water and complying with stringent guidelines and treatment standards. Problems associated with the treatment of low-turbidity water are not confined to Nova Scotia; several other provinces, British Columbia, Manitoba and Ontario share similar water characteristics of drinking water sources. The treatment of low turbidity water is a challenge for these utilities as it requires maintaining the appropriate coagulant dosage that will ensure adequate particle and natural organic matter removal, while at the same time not enhancing the formation of disinfection by-products. Another concern associated with the treatment of such water is that when the particle content of the water is very low, charge neutralization will not be effective due to the weak contact between destabilized particles. Currently, nanoparticles are not regulated as water contaminants, and thus it is unclear whether the existing filtration treatment practices are capable of removing them from drinking water. Obtaining in-depth information on nanoparticle characteristics in drinking water sources will provide a valuable resource that can assist in the development of future treatment strategies. In this research, characteristics of four synthetic nanoparticles cerium dioxide (CeO2), ferric oxide (Fe2O3), silicon dioxide (SiO2) and titanium dioxide (TiO2) were investigated in Milli-Q water for particle size, surface area, and surface potential using different characterization techniques. Water samples from Pockwock Lake were also characterized for naturally occurring nanoparticles. After initial testing, titanium dioxide (TiO2) nanoparticles were selected to examine particle removal at bench-scale filtration experiments, under operating conditions similar to those practiced at the J.D. Kline Water Supply Plant, Halifax, NS, Canada. Filter performance for the deposition of TiO2 nanoparticles was evaluated through the calculation of its attachment efficiency and coefficient under various water chemistry conditions. The calculated filter efficiency was then applied to simulate natural nanoparticles removal from water. The results of the research indicate that the investigated nanoparticles behaved similar to natural particles and formed aggregates with larger particle sizes in Milli-Q water. Among the tested nanoparticles, only titanium dioxide could be coagulated with alum, as its negative surface charge and zero point of charge were closer to that of alum. Filtration experiments revealed that TiO2 nanoparticles, when present in water, could successfully be removed by an alum dose of 8 mg/L. Indeed, removal in excess of 99.5% was achieved under the study conditions. Under the investigated water chemistry conditions, very low attachment efficiencies (?) of 0.001, 0.002 and 0.01, and filter coefficients (?) of -0.003, -0.001 and -0.02 were determined for the filters. Based on the calculated attachment efficiencies, and under the studied conditions, natural nanoparticles remain dispersed in the water and would not likely to be removed by direct filtration. The overall research findings represent a major step forward in nanoparticle removal by direct filtration.

Aleutian mink disease virus (AMDV) causes significant loss to the mink industry in Nova Scotia (NS). Contaminated water is a speculated virus source therefore my objective was to develop a method for detection of AMDV in water samples. Initially, the quality and quantity of AMDV DNA extracted by four commercial kits was evaluated by PCR. Next, viral capture by adsorption-elution filtration was tested using spiked water samples. The 1MDS filter method was superior or comparable to the MgCl2 filter method and outperformed the AlCl3 method. Lastly, 16 watershed samples from Southwest NS and 11 samples from two AMDV-infected ranches were tested. Five ranch samples from the two ranches tested positive. Three samples, containing more than 22 virus copies/µL after concentration were quantifiable. Pre-concentration, these samples contained 16,787 to 33,471 virus copies/mL. In conclusion, although further optimization is required, a method for the detection of AMDV in water samples was developed.

Research has shown biological filtration can be a successful treatment for manganese (Mn) removal from groundwater and surface water. In this study, bench-scale direct biofiltration was used to remove Mn and dissolved organic carbon (DOC) from a pH 6 surface water source in Halifax, Canada. The removal of Mn in pH 6 surface water was significantly (? = 0.05) removed with 200-300 µg/L phosphorus (P), and 500 µg/L hydrogen peroxide (H2O2). DOC removal was significantly (? = 0.05) improved with granular activated carbon (GAC) media, P enhancement at 200-300 µg/L, and H2O2 enhancement at 500 µg/L. Mn was likely removed by biological oxidation and physical adsorption to biogenic Mn and iron (Fe) oxides. These results show direct biofiltration of surface water at pH 6 can remove Mn below the 50 µg/L aesthetic guideline from a Mn loading of over 1 mg/L. Further research is required to verify the microbial mechanism.

Podocytes are specialized epithelial cells which wrap glomerular capillaries with numerous interdigitating foot processes (FP). Between adjacent FPs a unique junction, the slit diaphragm (SD), functions as the final blood filtration barrier. Actin organization is critical for maintaining FP structure and SD function, and the adaptor protein Nck can bind an intracellular SD component to couple it with actin regulators. Podocyte-specific deletion of Nck in mice results in proteinuria and FP effacement. To better understand FP remodelling, we have pursued a transgenic mouse model utilizing an inducible and reversible dominant negative Nck (DN-Nck) to prevent signalling to actin regulators, exclusively in podocytes. Effects of DN-Nck were first confirmed in vitro, and transgenic mice were then generated and induced to express DN-Nck. Despite obtaining several mice which exhibited a mild renal phenotype, transgene expression appeared to be lost in successive generations. Full in vivo analysis awaits generation of additional transgenic founders.

Tikslas. Ištirti alksnių, kaip atsinaujinančių energetinių augalų, džiovinimo procesą. Objektas. Du skirtingi džiovinimo būdai: konvekcinis ir aukštatemperatūrinis džiovinimas. Smulkinti ir nesmulkinti alksniai. Lietuvoje ką tik nupjautos medienos drėgnis gali svyruoti nuo 50 % iki 70 % drėgnio. Siekiant išvengti ir apsaugoti medieną nuo mikrobiologinių veiksnių ir savaiminio kaitimo, laikymo procesas turi būti kontroliuojamas ir medieną būtina išdžiovinti iki 8-15% drėgnio. Pateikto darbo literatūros apžvalgoje išanalizuota miško kirtimo atliekų naudojimo kurui galimybės, bei laikymo ir sandėliavimo parametrai. Ištirtas dvejopas alksnio kirtimo atliekų džiovinimas, panaudojant skirtingas džiovinimo temperatūras, bei tiekiamus oro filtracijos greičius. Nustatyta, kad džiovinant alksnius aktyviąja ventiliacija džiovinimas yra ekonomiškiausias ir labiausias atitinka natūralias gamtos sąlygas. / Purpose of the study. Investigate alder as a renewable energy crop, drying process. The object of the work. Two different drying methods: convection and high temperature drying. Alder chips and whole wood. Lithuania freshly cut wood moisture content can range from 50 % to 70 % moisture. In order to prevent and protect the wood from microbiological factors and self-heating, the storage process has to be controlled and the wood must be dried to a moisture content of 8 – 15 %. Literature of work review analyzed the logging waste for fuel options, and storage parameters. Investigated dual alder cutting waste drying, using different drying temperatures. It was found that drying Alder with active ventilation is the most economical and most natural drying method.

No abstract available. / Thesis (Ph.D.)-University of Natal, Durban, 1991.