The propagation of contaminants in the environment continues to threaten public health and safety. Conventional analytical techniques for environmental detection require centralized facilities and intensive resources for operation. An effective implementation of a wide network of field deployable point-of-use (POU) sensors can potentially enable real-time monitoring of water quality parameters and inform decision making on public health outbreaks. The use of nanotechnology and field-deployable analytical tools can potentially advance the development of POU sensors for future field application. In this dissertation, we developed environmental sensing techniques that utilize nanocomposites made of low-cost, biocompatible, and sustainable nanomaterials combined with Raman spectroscopy. First, a technology pre-assessment was performed that included a comprehensive evaluation of cellulose-derived nanocomposites and nanobiotechnology enabled techniques for their sustainable long-term environmental application. Furthermore, to contribute to the better understanding of the potential environmental implications of nanomaterial production and application, life cycle assessment (LCA) was used to evaluate the environmental impacts of six iron precursors and seven iron oxide nanoparticle synthesis methods. Secondly, in the technology development step, gold (Au) and iron oxide (Fe3O4) nanoparticles were incorporated onto bacterial cellulose nanocrystals and nanoscale magnetite were synthesized. As proof-of-concept environmental applications, the Au@Fe3O4@BCNCs were applied for the magnetic separation and surface-enhanced Raman scattering (SERS) detection of malachite green isothiocyanate (MGITC), and nanoscale magnetite were applied for phosphate (PO43-) removal and recovery from synthetic urine matrices. Finally, in the technological application step, three environmental sensing applications are presented that use nanomaterial-based sensor platforms and/or Raman spectroscopic techniques. The first application involved using Lectin-modified BCNCs coupled SERS and machine learning for discrimination of bacterial strains. The second application presents a simple Raman-stable isotope labeling approach for the study of viral infection of bacteria. The third application involved use of SERS pH nanoprobes for measuring pH in droplets of complex matrices (e.g., DMEM cell culture media, human saliva). / Doctor of Philosophy / The current generation of analytical tools for environmental detection rely upon centralized facilities and intensive resources for operation. The combination of nanotechnology and field deployable analytical tools can aid in the development of point-of-use (POU) sensors for field monitoring of environmental contaminants. In this dissertation, we combined low-cost, biocompatible, and sustainable nanomaterials with Raman spectroscopy-based techniques to develop potentially field-deployable environmental sensing techniques. First, a technology pre-assessment was performed which involved a comprehensive evaluation of cellulose-derived nanocomposites and nanobiotechnology enabled techniques for their sustainable long-term environmental application. Furthermore, life cycle assessment (LCA) was used to evaluate the environmental impacts of iron oxide nanoparticle synthesis methods to better understand environmental impacts of nanoparticle production. Secondly, in the technology development step, we developed the nanocomposites: Au and Fe3O4 nanoparticles incorporated bacterial cellulose nanocrystals and nanoscale magnetite. As proof-of-concept environmental applications, the Au@Fe3O4@BCNCs were used for the detection of malachite green isothiocyanate (MGITC), and the nanoscale magnetite were used for phosphate (PO43-) removal and recovery from synthetic urine. Finally, in the technological application step, (1) selective detection of bacteria was performed using lectin-modified BCNCs as SERS biosensors coupled with SERS and machine learning. (2) Viral infection of bacteria was evaluated using Raman spectroscopy and Deuterium isotope labeling, and (3) pH in micro-droplets of DMEM cell culture media and human saliva were observed using SERS pH nanoprobes.

Per- and polyfluoroalkyl substances (PFAS) are a class of man-made contaminants of increasing human health concern due to their resistance to degradation, widespread occurrence in the environment, bioaccumulation in human and animal organ tissue, and potential negative health impacts. Drinking water is suspected to be a primary source of human PFAS exposure, so the US Environmental Protection Agency (US EPA) has set interim and final health advisories for several PFAS species that are applicable to municipal water supplies. However, private drinking water supplies may be uniquely vulnerable to PFAS contamination, as these systems are not subject to EPA regulation and often include limited treatment prior to use for drinking or cooking. The goal of this study was to determine the incidence of PFAS contamination in private drinking water supplies in two counties in Southwest Virginia (Floyd and Roanoke), and to examine the potential for reliance on citizen-science based strategies for sample collection in subsequent broader sampling efforts. Samples for inorganic ions, bacteria, and PFAS analysis were collected on separate occasions by homeowners and experts at the home drinking water point of use (POU) in 10 Roanoke and 10 Floyd County homes for comparison. Experts also collected an outside tap PFAS sample. At least one PFAS compound was detected in 76% of POU samples collected (n=60), with an average total PFAS concentration of 23.5 parts per trillion (ppt). PFOA and PFOS, which are currently included in EPA health advisories, were detected in 13% and 22% of POU samples, respectively. Of the 31 PFAS species targeted, 15 were detected in at least one sample. On average, a single POU sample contained approximately 3 PFAS, and one sample contained as many as 8 different species, indicating that exposure to PFAS in complex mixtures is worth noting. Although there were significant differences in total PFAS concentrations between expert and homeowner collected samples (Wilcoxon, alpha = 0.05), it is unclear whether this difference was due to contamination by the collector or the water usage and time of day of sampling (i.e. morning, afternoon). It is worth noting that there was no significant difference in the number of PFAS species in the samples collected by homeowners and experts. Given the considerable variation in PFAS detections between homes, future studies reliant on homeowner collection of samples appears possible given proper training and instruction to collect at the same time of day (i.e. first thing in the morning). / Master of Science / Per- and polyfluoroalkyl substances (PFAS) belong to a large family of manmade compounds that are commonly used in a variety of household and consumer products due to their unique water and stain resistant properties. PFAS compounds are not easily broken down in the environment and have been detected globally in air, soil, and water samples. In addition to their environmental detections, PFAS are slow to be removed from the body after ingestion and known to cause negative health effects in concentrations less than one part per trillion. Drinking water is considered to a main source of PFAS consumption for humans; as such, the US Environmental Protection Agency (US EPA) has set strict, but not legally binding, interim and final health advisories (HA) for four types of PFAS. However, these health advisories only apply to public water services and do not cover private drinking water systems, such as wells or springs, which are the full responsibility of the well owner. Private drinking water system users often do not treat their water before drinking which may make these systems uniquely vulnerable to PFAS contamination. This study focused on 20 total homes, 10 in Roanoke County and 10 in Floyd County to see if PFAS was present and to determine whether or not homeowners would be able to collect their own samples for PFAS analysis at home as accurately as researchers or experts with proper instructions. Homeowners and experts collected drinking water samples inside at a point of use (POU), usually at a kitchen faucet, and outside of the home, usually from a tap. PFAS were present in 76% (n=60) of POU samples, with an average combined concentration of 23.5 parts per trillion (ppt). The two most well studied PFAS, PFOA and PFOS were detected in 13% and 22% of POU samples, respectively. It was also common to detect at least 3 PFAS in a single sample. Although there were differences in total average concentrations of PFAS in samples collected by homeowners and experts, variation could be caused by several factors indicating that with proper training and instruction it is likely future studies could still rely on homeowners to collect samples for PFAS analysis.

L'éventail thérapeutique utilisé en chimiothérapie antitumorale fait appel à des molécules ayant un indice thérapeutique limité dû à leur faible sélectivité d'action. C'est pourquoi nous développons au laboratoire de nouvelles approches pour guider la conception d'agents antitumoraux plus sélectifs. Cette approche s'intègre dans un design rationnel de ligands de l'ADN qui inhibent l'activité de liaison à l'ADN de facteurs de transcription afin de réguler l'expression de certains gènes.<br />Les dérivés DB, retenus pour cette étude, sont des molécules synthétisées par les Prs David Boykin et David Wilson (Atlanta) qui se fixent sur des séquences spécifiques dans le petit sillon de l'ADN. Ainsi, le composé diphényl-furane DB75 se lie en monomère à des séquences riches en paires de bases AT, alors que le dérivé phényl-furane-benzimidazole DB293 reconnaît la séquence 5'-ATGA en dimère. Cette reconnaissance «séquence-spécifique» pourrait cibler spécifiquement des interactions ADN-facteurs de transcription impliquées dans la régulation des gènes et la prolifération cellulaire.<br />Dans cette optique notre travail a été de déterminer la spécificité d'interaction à l'ADN de nouvelles molécules et d'en évaluer leur distribution cellulaire afin de pouvoir, dans un second temps, étudier la modulation de la liaison à l'ADN de facteur de transcription après fixation des dérivés.<br />Ainsi, nous nous sommes tout d'abord intéressés à la distribution cellulaire des composés DB dérivant du DB75 et du DB293 afin de déterminer s'ils pénètrent efficacement dans la cellule et se dirigent vers l'ADN nucléaire. Les résultats obtenus valident ceux publiés précédemment (Lansiaux et al., 2002a, 2002b) et montrent le faible impact des modifications du corps polycyclique sur la distribution des composés DB. Ainsi, les composés diphényl-furanes substitués sur le cycle furane, pénètrent efficacement dans le noyau alors que seules certaines substitutions sur les groupements phényles empêchent la molécule de pénétrer dans le noyau. Les conséquences cellulaires sont surprenantes puisque ces derniers composés présentent une très bonne cytotoxicité. Dans un second temps, nous avons étudié la spécificité et l'affinité de ces dérivés pour l'ADN. Nous avons ainsi découvert de nouveaux ligands des sites riches en paires de bases AT et des séquences ATGA qui ont permis de compléter nos connaissances des relations structure/affinité de ces composés.<br />Afin de déterminer si cette famille de ligands peut moduler sélectivement l'activité de liaison à l'ADN de facteurs de transcription, un criblage en mode compétitif de l'activité de 54 facteurs de transcription a été réalisé avec le DB293. Pour cela nous avons utilisé une approche innovante basée sur le principe des macroarrays : les membranes Transignal/Protein/DNA array I. Nous avons mis en évidence l'inhibition de la fixation de Pit-1 et Brn-3, deux facteurs de transcription à domaine POU dont les sites consensus contiennent un site riche en paires de bases AT et la séquence 5'-ATGA. Cependant, la seule présence d'un site 5'-ATGA ne prévient pas l'inhibition de l'activité de liaison à l'ADN par le DB293 puisque le facteur de transcription IRF-1 présentant aussi un site 5'-ATGA dans son site consensus n'est pas inhibé par le DB293. Nous avons montré que le DB293 interagit en dimère aux séquences 5'-ATGA des sites consensus Brn-3 et Pit-1 mais pas sur celui de IRF-1.<br />En parallèle, un ciblage de facteurs de transcription associés de manière privilégiée à un cancer donné et se liant au même type de séquence que les composés DB a orienté notre étude sur le complexe de transcription PBX/HoxA9. Ce complexe protéique se lie à une séquence nucléotidique à la fois riche en paire de base AT et contenant un site ATGA. Les membres de ce complexe sont sur-exprimés ou transloqués dans bon nombre de leucémies aiguës myéloïdes, lymphoïdes ou de syndromes myéloprolifératifs. Des tests d'interaction protéine/ADN nous ont permis de sélectionner des composés empêchant la fixation de HoxA9 sur sa séquence ADN cible. Les premiers résultats prometteurs dans la cellule montrent une toxicité induite par nos dérivés sur des cellules dont la prolifération est dépendante de l'activité de HoxA9 alors que cette toxicité est moindre dans des cellules n'exprimant pas HoxA9. Des tests clonogéniques effectués sur des cellules de moelle osseuse transformées par HoxA9 montrent un effet antiprolifératif du composé sélectionné qui est plus important sur les progéniteurs les moins engagés dans les voies de différentiation hématopoïétique.<br /><br />De plus, le criblage de nouvelles séries de molécules dicationiques a permis d'identifier 3 nouveaux composés, les dérivés DB1255, DB1242 et RT-29 qui se lient à des séquences originales riches en paires de base GC. Il s'avère que le composé DB1255 inhibe efficacement la fixation du facteur de transcription Erg sur son site consensus EBS.<br /><br />Cette étude montre pour la première fois l'inhibition de la fixation de facteurs de transcription par les composés DB et ouvre ainsi de nombreuses pistes prometteuses dans l'inhibition spécifiques de facteurs de transcription impliquées dans des processus de tumorogenèse.

Gram-negative infection has been linked to hospital water although few studies have examined whether water systems are reservoirs of nosocomial pathogens. This study investigated longitudinal recovery of the opportunistic pathogens Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinetobacter baumannii from water outlets of a haematology unit and evaluated Point-Of-Use Filtration (POU-F) as a control measure. In a two-year double cross-over trial, water samples and swabs were taken weekly from 39 showers/taps on the unit. Four study phases alternated between non-filtered (Phases 1 &amp; 3), and filtered outlets (Phases 2 &amp; 4) using Pall AquasafeTM 14-day filters. In Phases 1 &amp; 3; 99% of 1396 samples yielded bacterial growth, with colonies generally too numerous to count. Target species were isolated from 22% of water samples (P. aeruginosa 14%; S. maltophilia 10%) and 10% of swabs. P. aeruginosa was particularly associated with handwash stations and S. maltophilia with showers. A. baumannii was not isolated. With POU-F; 22% of 1242 samples yielded bacterial growth (mean CFU/100ml ,4.6). S. maltophilia was isolated only once from water but never from outlet swabs. PCR typing identified clusters of isolates colonizing different outlets over time but no clear association between water and patient isolates was identified. The incidence of Gram negative infections remained low throughout the study. Without POU-F, water from taps/showers represented a source of bacteria including the target species. POU-F substantially reduced the frequency and number of target species from every outlet, and merits further investigation as an intervention to protect immunocompromised patients from opportunistic pathogens.

This work deals with problematic of standard IEC61850, mainly with chapter IEC 61850-9-2 LE which is commonly known as Process bus communication. There are described advanced tools of the control system COM600 with detail description of their configuration in this work. It also deals with configuration of IEC 61850-9-2 LE with Relion family protection relays and its implementation to the control system COM600. The main aim of this work is focused on configuration of IEC 61850-9-2 standard with protection relays, configuration and detail description of COM600 advanced tools, description of Logic processor, further custom design and appliaction configuration global reset of Logic procesor in control system COM600.

Gram-negative infection has been linked to hospital water although few studies have examined whether water systems are reservoirs of nosocomial pathogens. This study investigated longitudinal recovery of the opportunistic pathogens Pseudomonas aeruginosa, Stenotrophomonas maltophilia and Acinetobacter baumannii from water outlets of a haematology unit and evaluated Point-Of-Use Filtration (POU-F) as a control measure. In a two-year double cross-over trial, water samples and swabs were taken weekly from 39 showers/taps on the unit. Four study phases alternated between non-filtered (Phases 1 & 3), and filtered outlets (Phases 2 & 4) using Pall AquasafeTM 14-day filters. In Phases 1 & 3; 99% of 1396 samples yielded bacterial growth, with colonies generally too numerous to count. Target species were isolated from 22% of water samples (P. aeruginosa 14%; S. maltophilia 10%) and 10% of swabs. P. aeruginosa was particularly associated with handwash stations and S. maltophilia with showers. A. baumannii was not isolated. With POU-F; 22% of 1242 samples yielded bacterial growth (mean CFU/100ml ,4.6). S. maltophilia was isolated only once from water but never from outlet swabs. PCR typing identified clusters of isolates colonizing different outlets over time but no clear association between water and patient isolates was identified. The incidence of Gram negative infections remained low throughout the study. Without POU-F, water from taps/showers represented a source of bacteria including the target species. POU-F substantially reduced the frequency and number of target species from every outlet, and merits further investigation as an intervention to protect immunocompromised patients from opportunistic pathogens. / School of Life Sciences, University of Bradford and Pall Medical (Pall Europe Ltd)

No description available.

The central theme of development, how cells are organized into functional structures and assembled into whole organisms, is addressed by developmental biology. One important feature of embryonic development is pattern formation, which is the generation of a particular arrangement of cells in three-dimensional space at a given point of time. Central to this work is the model system of the zebrafish, Danio rerio. The aim of the first part of this study was to try to understand how a distinct part of the embryonic brain called midbrain-hindbrain boundary (MHB), a region that acts as an organizer for the adjacent brain regions, is established in vertebrates. spiel-ohne-grenzen (spg) is one mutant which interferes with MHB development. Here, I addressed the role of pou2 in brain development by molecular, phenotypical and functional analysis. By genetic complementation and mapping I could elucidate the molecular nature of this mutant and found that the pou2 gene encoding the POU domain transcription factor is affected in spg mutant embryos. By chromosomal syntenic conservation, phylogenetic sequence comparison, and expression and functional data I imply that pou2 is the orthologue of the mammalian Oct4 (Pou5F1) gene. I find by detailed expression and transplantation analysis that pou2 is cell autonomously required within the neuroectoderm to activate genes of the MHB and hindbrain primordium, like pax2.1, wnt1, gbx2 or krox20. By gain-of-function experiments I demonstrate that pou2 synergizes with Fgf8 signaling in order to activate particularly the hindbrain primordium. Since pou2 is already provided to the embryo by the mother, I generated embryos which lack maternal and zygotic pou2 function (MZspg) to reveal a possible earlier than neuroectodermal role of pou2. In the second part of this work I demonstrate that pou2 is a key factor controlling endoderm differentiation. By expression and gain-of-function analysis I suggest a cell autonomous function for Pou2 in the first step of endodermal differentiation. By gain-of-function experiments involving the gene encoding the HMG transcription factor Casanova (Cas) I show that both Cas and Pou2 are necessary to activate expression of the endodermal differentiation marker sox17 in a mutually dependent way, and that the ability of Cas to ectopically induce sox17 strictly requires Pou2. I conclude that both maternal and zygotic pou2 function is necessary for commitment of endodermal progenitor cells to differentiate into endodermal precursor cells.

No description available.

The central theme of development, how cells are organized into functional structures and assembled into whole organisms, is addressed by developmental biology. One important feature of embryonic development is pattern formation, which is the generation of a particular arrangement of cells in three-dimensional space at a given point of time. Central to this work is the model system of the zebrafish, Danio rerio. The aim of the first part of this study was to try to understand how a distinct part of the embryonic brain called midbrain-hindbrain boundary (MHB), a region that acts as an organizer for the adjacent brain regions, is established in vertebrates. spiel-ohne-grenzen (spg) is one mutant which interferes with MHB development. Here, I addressed the role of pou2 in brain development by molecular, phenotypical and functional analysis. By genetic complementation and mapping I could elucidate the molecular nature of this mutant and found that the pou2 gene encoding the POU domain transcription factor is affected in spg mutant embryos. By chromosomal syntenic conservation, phylogenetic sequence comparison, and expression and functional data I imply that pou2 is the orthologue of the mammalian Oct4 (Pou5F1) gene. I find by detailed expression and transplantation analysis that pou2 is cell autonomously required within the neuroectoderm to activate genes of the MHB and hindbrain primordium, like pax2.1, wnt1, gbx2 or krox20. By gain-of-function experiments I demonstrate that pou2 synergizes with Fgf8 signaling in order to activate particularly the hindbrain primordium. Since pou2 is already provided to the embryo by the mother, I generated embryos which lack maternal and zygotic pou2 function (MZspg) to reveal a possible earlier than neuroectodermal role of pou2. In the second part of this work I demonstrate that pou2 is a key factor controlling endoderm differentiation. By expression and gain-of-function analysis I suggest a cell autonomous function for Pou2 in the first step of endodermal differentiation. By gain-of-function experiments involving the gene encoding the HMG transcription factor Casanova (Cas) I show that both Cas and Pou2 are necessary to activate expression of the endodermal differentiation marker sox17 in a mutually dependent way, and that the ability of Cas to ectopically induce sox17 strictly requires Pou2. I conclude that both maternal and zygotic pou2 function is necessary for commitment of endodermal progenitor cells to differentiate into endodermal precursor cells.