No description available.

The effect of added iron on the growth of Clostridium botulinum type A in a chemically defined medium was studied. Growth of C. botulinum was supported by an iron level of 0.05 ug/ml with maximum growth observed at a level of 3 ug iron/ml. Electron paramagnetic resonance (EPR) studies were conducted to detect the presence of iron-sulfur centers and iron-nitric oxide complexes in untreated and nitrite treated cell-free extracts of C. botulinum type A. Untreated extracts of C. botulinum exhibited EPR signals in the oxidized and reduced states characteristic of a "HiPiP-type" iron-sulfur center (g=2.02) in the oxidized state and a reduced signal at g=l.94, characteristic of a reduced iron-sulfur center. Extracts of C. botulinum treated with nitrite exhibited an EPR signal at g=2.035, characteristic of iron-nitrosyl complexes, with the simultaneous disappearance of the the signal at g=l.94. This indicates that nitrite reacts with the iron-sulfur centers in botulinal cells to form iron-nitrosyl complexes. Addition of ascorbate with nitrite intensified the EPR signal at g=2.035, probably by enhancing the reduction of nitrite to nitric oxide. A cytochrome c reduction method was used for the determination of ferredoxin activity in untreated and nitrite treated cells of C. botulinum type A from which ferredoxin had been partially purified. Untreated extracts of C. botulinum reduced cytochrome c which demonstrates ferredoxin activity within the cells. Treatment of the cells with nitrite at a level of 1000 ppm for 45 min was found to inhibit ferredoxin activity by 90%. Boiling the partially purified ferredoxin from the untreated cells for 5 min inactivated the protein. Pyruvate-ferredoxin oxidoreductase activity in partially purified extracts of nitrite treated and untreated cells of C. botulinum was determined by assaying for FAD reduction and acylhydroxamate formation. Nitrite treated cells exhibited an inhibition of 70% of FAD reducing activity and 80% inhibition of acylhydroxamate formation when compared to the untreated cells. Boiling inhibited the activity of partially purified oxidoreductase activity by more than 90% in both the assays.

Made available in DSpace on 2014-07-29T15:29:04Z (GMT). No. of bitstreams: 1 DISSERTACAO - HUGO DELLEON-1.pdf: 1681733 bytes, checksum: ec21194046431954674916776c620d9e (MD5) Previous issue date: 2009-05-27 / Although water is of vital importance for living beings, due to antropic action it becomes a way of dissemination of several microorganisms, which reach aquatic environments through the faeces of man and other animals and can cause several illnesses, especially for immunocompromised individuals. During routine environmental monitoring, coliform bacteria are normally used as a microbiological parameter of water quality, which does not evidence its contamination by viruses. Several researchers have proposed the detection of adenovirus (AdVs) by PCR as a molecular index to monitor other enteric viruses. AdVs are among the most persistent and ubiquitous enteric viruses present in water and associated with a variety of clinical manifestations. This study aimed to evaluate the quality of water collected from lakes and rivers in Goiânia as to the occurrence of AdVs. Water samples were collected monthly, from December 2007 to November 2008, at five different points in Goiânia (lakes of Bosque dos Buritis and Vaca Brava park, João Leite and Meia Ponte rivers downstream and upstream the municipal sewage treatment plant). The analyses were carried out at the Laboratório de Diagnóstico Genético e Molecular and Laboratório de Genética Molecular e Citogenética, Universidade Federal de Goiás. All the samples were filtered in a positively-charged nylon membrane followed by molecular detection using PCR and semi-nested PCR. Also, we performed physical-chemical and bacteriological tests to correlate these results with the occurrence of AdVs. Simultaneously, the Núcleo de Pesquisas em Agentes Emergentes e Re-emergentes carried out a meta-analysis to evaluate three methods of concentration of AdVs coupled to molecular detection in samples of untreated water. Since 29 out of the 54 water samples collected were positive for AdVs (39.2%), our results suggest the use of the methodology proposed in the present study for the detection of these pathogens in water. We observed statistically significant difference between nitrites, phosphates, fixed residues, total residues and the occurrence of AdVs, whereas no correlation was observed between fecal coliforms and AdVs. Furthermore, the occurrence of AdVs in the state of Goiás shows a seasonal trend. Based on the 33 studies selected for the meta-analysis, it was possible to get to the following interpretations: the most effective method to detect AdVs in samples from rivers or lakes was ultracentrifugation combined with nested-PCR; it is advisable to use a combination of microfiltration membrane and ultrafugation with the subsequent diagnosis using qPCR to detect AdVs in samples of treated and untreated sewage. This has been the first study carried out for the detection and monitoring of AdVs in water bodies in the Midwestern Region of Brazil and the present results may be useful to propose the eco-epidemiological profile of AdVs or even the routes of some neglected diseases, which points out the need to define a virus indicator / Embora a água seja de vital importância para os seres vivos, em decorrência da ação antrópica torna-se meio de disseminação de inúmeros microrganismos, que chegam aos ambientes aquáticos por meio das fezes do homem e de outros animais, podendo desencadear diversas doenças, sobretudo em indivíduos imunocomprometidos. Em rotina de monitoramento ambiental, normalmente são utilizadas bactérias do grupo dos coliformes fecais como parâmetro microbiológico de qualidade das águas, o que não evidencia sua contaminação por vírus. Alguns pesquisadores têm proposto a detecção de adenovírus (AdVs) por PCR como indexação no monitoramento de outros vírus entéricos. AdVs estão entre os mais persistentes e ubíquos vírus entéricos presentes em águas e associados com uma variedade de manifestações clínicas. Objetivou-se avaliar a qualidade da água de rios e lagos da cidade de Goiânia em relação à ocorrência de AdVs. Amostras de água foram coletadas mensalmente, entre dezembro de 2007 e novembro de 2008, em cinco diferentes pontos de Goiânia (lagos do Bosque dos Buritis e parque Vaca Brava e rios João Leite e Meia Ponte a jusante e montante da estação de tratamento de esgoto municipal). As análises laboratoriais foram realizadas pelo Laboratório de Diagnóstico Genético e Molecular e Laboratório de Genética Molecular e Citogenética, Universidade Federal de Goiás. Inicialmente, as amostras foram filtradas em membrana de nylon carregada positivamente e, em seguida, submetidas a detecção molecular por PCR e semi-nested PCR. Também foram realizados testes físico-químicos e bacteriológicos para correlacionar estes resultados com a ocorrência de AdVs. Concomitantemente, o Núcleo de Pesquisas em Agentes Emergentes e Re-emergentes conduziu uma metanálise avaliativa de três metodologias de concentração de AdVs acopladas à detecção molecular em amostras de águas não tratadas. Das 54 amostras coletas, 29 foram positivas para AdVs (39,2%), sugerindo o uso da metodologia proposta neste estudo para detectar estes patógenos em água. Foi observada diferença estatisticamente significativa entre nitritos, fosfatos, resíduos fixos, resíduos totais e a ocorrência de AdVs, mas não foi observada correlação entre coliformes fecais e AdVs. Além disso, a ocorrência de AdVs no estado de Goiás exibiu tendência à sazonalidade. Na metanálise, a partir dos 33 artigos selecionados foi possível fazer as seguintes interpretações: para detectar AdVs em amostras de rios ou lagos, o método mais eficiente foi a ultracentrifugação em combinação com nested-PCR; para a detecção de AdVs em amostras de esgoto tratado e não tratado é aconselhável utilizar uma combinação de microfiltração em membrana e ultrafiltração com subsequente diagnóstico por qPCR. Este foi o primeiro estudo a detectar e monitorar AdVs em cursos de água na Região Centro-Oeste do Brasil e os presentes resultados podem ser úteis para propor o perfil eco-epidemiológico dos AdVs ou até mesmo das rotas de algumas doenças que são negligenciadas, o que demonstra a necessidade de definir um indicador viral

No description available.

The Central Appalachian region is home to several resource-extraction industries, a host of globally unique aquatic wildlife species, and region-wide poverty. These overlapping circumstances make solving environmental issues in the region challenging. Of particular focus is the coal mining industry, both because of its prevalence and because of controversial methods of practice such as mountain top mining. One of the primary concerns in the region is the extirpation of sensitive aquatic macroinvertebrate species. Several studies have suggested the primary driver of this loss of biodiversity is due to increased conductivity in streams impacted by these mining practices. The reality is that several pollutant sources coexist in these Central Appalachian watersheds. Because of geographic isolation, many headwater communities lack proper sewerage and discharge directly into nearby waterways, compounding potential effects of upstream mining activities. Additionally, several legacy sites exist throughout the Appalachian region, both underground and surface mining in nature. To best mitigate ecological impacts of all of these pollutant types, relative contributions of each must be understood, as well as the nature of the pollution contributed by each. As a contribution towards this region-wide need for better information on pollution, the studies comprising this dissertation seek to better understand the composition of these different pollutant sources and their in-stream contributions to conductivity. The first paper found that these sources are indeed distinct in their inorganic ion make-up: surface coal mining was found to contribute primarily Ca, K, Ni, Se, and SO₄⁻², while untreated household waste (UHW) was primarily associated with P. HCO₃⁻ Mn, and Si were found to be associated with a legacy underground discharge. The second and third scientific studies included here analyzed conductivity's effect on Virginia Stream Condition Index (VSCI) versus other water quality and habitat parameters as well as the effect of specific ion suites on VSCI score. Findings indicated that excellent habitat extends species resilience against elevated conductivity, with passing VSCI scores found at conductivity in the 600-800 µs/cm range in cases of excellent habitat metric scores. Meanwhile, VSCI score suppression was highly related to surface mining-related inorganic ions (Ca, K, Mg, Ni, and SO₄⁻²), but also negatively correlated with ions related to UHW (P and Na). These results indicate the need for quantification of biological responses to specific ions in order to initiate targeted mitigate of pollutants in Central Appalachian watersheds. / Ph. D.

Untreated human sewage pollution in surface water is of concern because it contributes to the degradation of aquatic ecosystems and it could be a potential hazard to human health. Also, any pollution of surface water, which ultimately supplies drinking water, may affect the drinking water quality. Improper operation and maintenance of separate storm sewer systems are prominent contributors of untreated sewage to source waters, resulting from illicit connections, leakage of sewers, or cross-connections. This thesis studied anthropogenic markers to track untreated sewage in an urban watershed with separate storm sewer system, under dry weather conditions. The main feature of these chemical markers is their degradation behavior at municipal wastewater treatment plants: some markers are completely removed (labile markers), whereas others show only partial or no removal at all (conservative markers). A set of ubiquitous chemical markers with practical analytical detection limits was selected to exploit the labile vs conservative distinction, and determine if untreated human sewage was discharged from stormwater outfalls. The presence of labile markers alone was not enough to confirm the occurrence of untreated sewage in stormwater outfalls. The concentration ratios between labile and conservative markers from several chemical groups (pharmaceuticals and personal care products, over-the-counter medications, artificial sweeteners, and human metabolites) created a chemical fingerprint of untreated sewage, and it was statistically demonstrated to track untreated human sewage in local stormwater outfalls. / Civil Engineering

Poor water quality is a global health concern affecting one billion people around the world. It is important to monitor water sources in order to maintain the quality of our drinking water and to avoid disease outbreaks. Targeting Escherichia coli as a faecal indicator is a widely used procedure, but the current methods are time consuming and not adequate to prevent spreading of faecal influence.   This Master thesis demonstrates the development of a near infrared fluorescence flow cytometer sensor system targeting Escherichia coli, using fluorescently labeled chicken IgY antibodies. The near infrared light was chosen to avoid fluorescence from blue-green algae that are present in the water source.   The hardware was developed with a 785  nm laser line to detect Alexa Fluor 790 labeled antibodies, using a photomultiplier tube or two different CMOS cameras. The antibodies were labeled using a commercial labeling kit, and evaluated using antibody binding assays and the developed hardware.   The IgY antibodies were successfully labeled with Alexa Fluor 790 and the function was maintained after the labeling process. The result demonstrates the principles of the sensor system and how it solved to the problem with fluorescence from blue-green algae. An aperture was used to overcome the suboptimal laser and filter setup, and to increase the sensitivity of the system. However, only a small fraction of the cells could be detected, due to challenges with the focal depth and loss of sensitivity in the photomultiplier tube at near infrared wavelengths. Further development is required to create a working product.

Abstract The duration of untreated psychosis (DUP) and its association with the course of illness in schizophrenia has been widely addressed, but the conclusions still remain essentially unclear. The studies with unselected samples and longitudinal data are few and needed. The aim of this dissertation was to study DUP and the long-term course of illness in schizophrenia in a meta-analysis and in the Northern Finland 1966 Birth Cohort (NFBC 1966). A meta-analysis of 31 original studies on the long-term association between DUP and clinical and social outcomes showed that long DUP had a small but statistically significant association with poor symptomatic, social, and global outcomes. However, there was no significant correlation between DUP and use of treatment, employment, and quality of life. In the NFBC 1966, the associations between DUP and the outcomes (n=89) were assessed with several measurements of mental and psychical state, treatment factors, education, and ability to work. In the short-term outcome, long DUP was associated with longer first hospitalization and increased risk of re-hospitalization. In the long-term, long DUP was associated only with a decreased rate of disability pension. When the association between DUP and brain structures using magnetic resonance imaging (MRI) was analyzed (n=46), long DUP correlated with decreased gray-matter density in the right hippocampus. DUP may be a modest marker of a more severe clinical phenotype regarding early outcome, but in the NFBC 1966, longer DUP seems to associate with better clinical and occupational outcomes. The relatively modest effect of DUP on outcomes indicates that shortening DUP may have positive effects on the long-term clinical course. However, it is unlikely that early intervention alone could significantly improve the overall long-term outcome of schizophrenia. Early detection of psychosis is one of the possibilities to achieve the improvement, especially in the short-term outcome of schizophrenia. / Tiivistelmä Hoitamattoman psykoosin kestoa ja sen yhteyttä skitsofrenian taudinkulkuun on tutkittu laajasti, mutta johtopäätökset asiasta ovat jääneet olennaisilta osilta epävarmoiksi. Aihetta koskevia valikoitumattomien aineistojen pitkittäisseurantoja on olemassa vain vähän. Tämän osajulkaisuväitöskirjan tavoitteena oli tutkia hoitamattoman psykoosin keston ja skitsofrenian taudinkulun pitkäaikaista yhteyttä meta-analyysin sekä Pohjois-Suomen vuoden 1966 syntymäkohorttiaineiston avulla. Meta-analyysi hoitamattoman psykoosin keston ja kliinisen ja sosiaalisen ennusteen välillä osoitti, että pidentynyt hoitamattomuus on tilastollisesti merkitsevästi yhteydessä vakavampiin oireisiin ja huonompaan sosiaaliseen toimintakykyyn sekä kokonaisennusteeseen pitkäaikaisseurannoissa. Merkitsevää yhteyttä ei ollut hoitamattoman psykoosin keston ja sairaalahoitojen määrän, työllistymisen tai elämänlaadun välillä. Pohjois-Suomen vuoden 1966 syntymäkohortissa tutkittiin hoitamattoman psykoosin yhteyttä taudinkulkuun ja ennusteeseen (n=89) ja aivojen rakenteeseen (n=46). Kahden ensimmäisen vuoden seurannassa pitkä hoitamattomuus oli yhteydessä pidempään ensimmäiseen sairaalahoitoon ja uuden sairaalahoidon kohonneeseen riskiin. Pitkäaikaisseurannassa pidentynyt hoitamattomuus oli merkitsevästi yhteydessä vähäisempään työkyvyttömyyseläkkeellä olemiseen. Kun aivojen rakennetta tutkittiin magneettikuvantamisen (MRI) avulla, löytyi yhteys pidentyneen hoitamattomuuden ja harmaan aineen pienemmän tiheyden välillä oikean hippokampuksen alueella. Hoitamattoman psykoosin keston tilastollisesti merkitsevä yhteys taudin eri ennusteisiin viittaa siihen, että psykoosin varhaisella tunnistamisella voi olla myönteisiä vaikutuksia. Muut mahdollisuudet parantaa skitsofrenian pitkäaikaisennustetta lienevät keskeisiä ja voivat tehostaa varhaisen tunnistamisen vaikutuksia.

No description available.

In recent years, due to growing environmental awareness, considerable attention has been given to the development and production of natural fibre reinforced polymer (both thermoset and thermoplastic) composites. The main objective of this study was to reinforce epoxy and polylactic acid (PLA) with hemp fibre to produce improved composites by optimising the fibre treatment methods, composite processing methods, and fibre/matrix interfacial bonding. An investigation was conducted to obtain a suitable fibre alkali treatment method to: (i) remove non-cellulosic fibre components such as lignin (sensitive to ultra violet (UV) radiation) and hemicelluloses (sensitive to moisture) to improve long term composites stability (ii) roughen fibre surface to obtain mechanical interlocking with matrices (iii)expose cellulose hydroxyl groups to obtain hydrogen and covalent bonding with matrices (iv) separate the fibres from their fibre bundles to make the fibre surface available for bonding with matrices (v) retain tensile strength by keeping fibre damage to a minimum level and (vi) increase crystalline cellulose by better packing of cellulose chains to enhance the thermal stability of the fibres. An empirical model was developed for fibre tensile strength (TS) obtained with different treatment conditions (different sodium hydroxide (NaOH) and sodium sulphite (Na2SO3) concentrations, treatment temperatures, and digestion times) by a partial factorial design. Upon analysis of the alkali fibre treatments by single fibre tensile testing (SFTT), scanning electron microscopy (SEM), zeta potential measurements, differential thermal analysis/thermogravimetric analysis (DTA/TGA), wide angle X-ray diffraction (WAXRD), lignin analysis and Fourier transform infrared (FTIR) spectroscopy, a treatment consisting of 5 wt% NaOH and 2 wt% Na2SO3 concentrations, with a treatment temperature of 120oC and a digestion time of 60 minutes, was found to give the best combination of the required properties. This alkali treatment produced fibres with an average TS and Young's modulus (YM) of 463 MPa and 33 GPa respectively. The fibres obtained with the optimised alkali treatment were further treated with acetic anhydride and phenyltrimethoxy silane. However, acetylated and silane treated fibres were not found to give overall performance improvement. Cure kinetics of the neat epoxy (NE) and 40 wt% untreated fibre/epoxy (UTFE) composites were studied and it was found that the addition of fibres into epoxy resin increased the reaction rate and decreased the curing time. An increase in the nucleophilic activity of the amine groups in the presence of fibres is believed to have increased the reaction rate of the fibre/epoxy resin system and hence reduced the activation energies compared to NE. The highest interfacial shear strength (IFSS) value for alkali treated fibre/epoxy (ATFE) samples was 5.2 MPa which was larger than the highest value of 2.7 MPa for UTFE samples supporting that there was a stronger interface between alkali treated fibre and epoxy resin. The best fibre/epoxy bonding was found for an epoxy to curing agent ratio of 1:1 (E1C1) followed by epoxy to curing agent ratios of 1:1.2 (E1C1.2), 1: 0.8 (E1C0.8), and finally for 1:0.6 (E1C0.6). Long and short fibre reinforced epoxy composites were produced with various processing conditions using vacuum bag and compression moulding. A 65 wt% untreated long fibre/epoxy (UTLFE) composite produced by compression moulding at 70oC with a TS of 165 MPa, YM of 17 GPa, flexural strength of 180 MPa, flexural modulus of 10.1 GPa, impact energy (IE) of 14.5 kJ/m2, and fracture toughness (KIc) of 5 MPa.m1/2 was found to be the best in contrast to the trend of increased IFSS for ATFE samples. This is considered to be due to stress concentration as a result of increased fibre/fibre contact with the increased fibre content in the ATFE composites compared to the UTFE composites. Hygrothermal ageing of 65 wt% untreated and alkali treated long and short fibre/epoxy composites (produced by curing at 70oC) showed that long fibre/epoxy composites were more resistant than short fibre/epoxy composites and ATFE composites were more resistant than UTFE composites towards hygrothermal ageing environments as revealed from diffusion coefficients and tensile, flexural, impact, fracture toughness, SEM, TGA, and WAXRD test results. Accelerated ageing of 65 wt% UTLFE and alkali treated long fibre/epoxy (ATLFE) composites (produced by curing at 70oC) showed that ATLFE composites were more resistant than UTLFE composites towards hygrothermal ageing environments as revealed from tensile, flexural, impact, KIc, SEM, TGA, WAXRD, FTIR test results. IFSS obtained with untreated fibre/PLA (UFPLA) and alkali treated fibre/PLA (ATPLA) samples showed that ATPLA samples had greater IFSS than that of UFPLA samples. The increase in the formation of hydrogen bonding and mechanical interlocking of the alkali treated fibres with PLA could be responsible for the increased IFSS for ATPLA system compared to UFPLA system. Long and short fibre reinforced PLA composites were also produced with various processing conditions using compression moulding. A 32 wt% alkali treated long fibre PLA composite produced by film stacking with a TS of 83 MPa, YM of 11 GPa, flexural strength of 143 MPa, flexural modulus of 6.5 GPa, IE of 9 kJ/m2, and KIc of 3 MPa.m1/2 was found to be the best. This could be due to the better bonding of the alkali treated fibres with PLA. The mechanical properties of this composite have been found to be the best compared to the available literature. Hygrothermal and accelerated ageing of 32 wt% untreated and alkali treated long fibre/PLA composites ATPLA composites were more resistant than UFPLA composites towards hygrothermal and accelerated ageing environments as revealed from diffusion coefficients and tensile, flexural, impact, KIc, SEM, differential scanning calorimetry (DSC), WAXRD, and FTIR results. Increased potential hydrogen bond formation and mechanical interlocking of the alkali treated fibres with PLA could be responsible for the increased resistance of the ATPLA composites. Based on the present study, it can be said that the performance of natural fibre composites largely depend on fibre properties (e.g. length and orientation), matrix properties (e.g. cure kinetics and crystallinity), fibre treatment and processing methods, and composite processing methods.