Thesis (Ph.D.)--Ohio University, November, 2004. / Title from PDF t.p. Includes bibliographical references (p. 161-171)

There is increasing evidence that repeat mild traumatic brain injury (rmTBI) may result in cumulative and long-term symptoms, more pronounced behavioural deficits, and neurodegeneration. Children have a greater susceptibility to head injury and represent a significant at risk population for rmTBI, especially those that participate in contact sports. Despite this, there is a paucity of data on rmTBI pathophysiology in the juvenile brain. The current study utilizes a novel awake closed head injury (ACHI) model to deliver repeat injuries to fully conscious juvenile rats. The ACHI model avoids the potential confounds of anaesthesia, and facilitates the assessment of neurological function immediately after each impact. Results indicate that the ACHI model produces acute neurological deficits after each impact, and that repeat injury worsens outcomes. Behavioural testing identified transient anxiety-like behaviour and motor impairment in response to rmTBI. The functional impairments and affective behaviour were in the absence of tau protein pathology. This study represents the first investigation of the consequences of rmTBI on the juvenile brain using an awake model of brain injury. / Graduate

The consequences of corrosion are extremely costly and troublesome. In manufacturing companies, for instance, corrosion is considered a chronic problem that causes sudden disruptions in many segments of operation including processing, production, transportation, and containment of commodity products. Protection against corrosion is, therefore, important, as it helps achieve service life extension for metals and reduction in corrosion-related costs. Risk reduction for catastrophic structural failures and accident prevention can also be realized. Broader application of protective coatings and corrosion inhibiting agents remains one of the best technical practices in minimizing the effects of corrosion. This study introduces different classes of polymers and organic compounds and their potential use as new groups of corrosion preventing materials. Firstly, the use of semiluorinated perfluorocyclobutyl (PFCB) aromatic ether polymers as coatings for corrosion prevention was examined. PFCB polymers share several important characteristics with commercial fluoropolymers including chemical resistance, thermal stability, mechanical strength, and low surface energy, but with enhanced processability. Secondly, the use of very small amounts of azole-based aromatic compounds was shown to effectively inhibit corrosion in acidic medium. Compared to other inhibitor agents, these compounds have the advantage of being less complex, inexpensive, environmentally friendly, and synthesized in a one-step approach. Thirdly, the use of a tetradiglycidyl-ether-based epoxy-amine resin as corrosion resistant coating was investigated both in its intact and artificially-damaged forms. This epoxy resin, which can be infused with preform materials, has been used in the development of carbon fiber composites for aircraft applications. Finally, the capability of a superhydrophobic perfluorinated polymer nanocomposite coating to resist corrosion was evaluated. The coating also displayed superoleophilicity, which led to its additional use in separating oil-water mixtures. Standard electrochemical methods such as open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization were used to evaluate the corrosion protection performance. Several other analytical techniques were also employed to characterize the quality and structure of the protective materials and supplement the results acquired from electrochemical analyses.

<p> Multiple impact tests were performed on mild steel. The pulse durations ranged from 15 to 250 milliseconds. Peak stresses extending to 135,000 p.s.i. were attained. </p> <p> A dynamic model, based on dislocation dynamics, was derived for polycrystalline metals and made specific to mild steel. The model provided a means of indirectly determining the dislocation velocity-stress exponent 𝑛 by experiment. </p> <p> An empirical flow function was evaluated which related dynamic load conditions to plastic deformation. This function is a further extension of the dynamic model. Several dislocation parameters are grouped together to pennit experimental evaluation of the strain rate effect on crystalline material. </p> <p> Experimental studies indicated that a given strain: </p> <p> 1) if produced by a single pulse, can be estimated by evaluation of the flow function for that load-time trace, or, </p> <p> 2) if produced by multiple impacts, can be estimated by the cumulative flow function, a summation of the flow functions for all impact traces. </p> <p> The multiple impact tests established the flow function as an equation of state. The plastic deformation could then be determined for a given dynamic load as long as the strain history is known. </p> <p> The theoretical model was used to support the experimental findings. </p> / Thesis / Master of Engineering (ME)

Mild cognitive impairment (MCI) is a medical diagnosis that is conceptualized as existing on a continuum between normal cognitive aging and dementia. While a growing body of research has established the impact of this condition on family members' emotional well-being, as well as the quality of family relationships, the reciprocal impact of family dynamics and the family environment on illness course has received much less attention. Expressed emotion (EE) is a measure of the family emotional climate that has been established as being highly predictive of relapse and symptom exacerbation for a variety of mental health disorders. The recent integration of attribution theory with EE has offered new insights into the underlying attitudes and beliefs that give rise to it. This mixed methods study applied the attribution model of EE to test the validity of EE in predicting the illness course of MCI, and to identify family members' attributions regarding MCI-related behaviors and symptoms that underlie their EE status. The study sample included 57 family dyads consisting of a person with MCI and a family member providing primary care or assistance. The results of the ANCOVA did not support the hypothesis that EE status would predict changes in the non-cognitive features of MCI over time. However, methods of thematic analysis revealed four major themes, or care partner attributional stances: (a) non-blaming, (b) blaming, (c) variable, and (d) no identified. The analysis also revealed three subthemes, or attributional styles, within the variable stance: (a) ambivalent, (b) mixed, and (c) complex. These attributional stances and styles intersected with family EE status in notable ways and form the basis for future research in this area, as well as clinical interventions with these families that promote adaptation to the illness. / Ph. D.

Disputats, Umeå universitet, 2006. / Härtill 3 uppsatser.

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2018-09-19T11:12:48Z No. of bitstreams: 1 texto completo.pdf: 1966574 bytes, checksum: 9a74f6b3cb6b04d280008a26f090b161 (MD5) / Made available in DSpace on 2018-09-19T11:12:48Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1966574 bytes, checksum: 9a74f6b3cb6b04d280008a26f090b161 (MD5) Previous issue date: 2017-02-23 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / A cultura do feijoeiro comum no Brasil, além do imenso valor que representa na cadeia econômica e para milhares de agricultores no país, é fundamental devido à contribuição que possui na segurança alimentar da população. Cultivares com evento de resistência ao Bean golden mosaic virus (begomovirus), vírus responsável por causar uma das doenças que mais afeta a produtividade da cultura no país, foram desenvolvidas após vários anos de pesquisas. Infecções durante testes em campo desses materiais por outro vírus, o Cowpea mild mottle virus (carlavirus), gerou novas preocupações tanto aos pesquisadores envolvidos no projeto do feijoeiro resistente ao mosaico dourado quanto aos produtores que aguardavam a liberação comercial dessas cultivares. Apesar de alguns trabalhos já terem sido desenvolvidos a fim de se avaliar os prejuízos produtivos que o CPMMV causa sobre as isolinhas transgênicas de feijoeiro, assim como sua distribuição, nenhum conhecimento se tem sobre a diversidade desse vírus em feijão comum ou transgênico no Brasil, e poucos trabalhos dessa natureza são encontrados na literatura até hoje. Nesse trabalho, buscou-se avaliar a variabilidade de populações do CPMMV para cada uma de quinze cultivares de feijoeiro comum, sendo dez transgênicas (resistentes ao BGMV) e cinco convencionais, em um campo experimental com ocorrência e transmissão natural do CPMMV. Também foram quantificados os níveis virais em cada cultivar a partir de três repetições. Para cada uma das quinze plantas representando 15 diferentes genótipos de feijoeiro comum, o genoma completo de cinco isolados de CPMMV foi sequenciado pela montagem de sequenciamentos de blocos de PCR. Diferenças foram encontradas na variabilidade dos cinco isolados de CPMMV em plantas transgênicas e em plantas convencionais. Os valores dos descritores de variabilidade π, S, K e Θ foram geralmente maiores nos grupos de isolados de plantas transgênicas. Isso se repetiu para todas as ORF’s virais analisadas. As ORF’s 2, 3 e 4 foram as que tiveram a maior diversidade registrada, enquanto que a diferenças entre os grupos já citados foi mais perceptível nas regiões das ORF’s 2, 5 e 6. Eventos de recombinação foram encontrados na ORF 1 viral, quase sempre ocorrendo em isolados de plantas transgênicas, assim como alguns na ORF 2 e 6. Analisando as sequencias da ORF 1, nota-se que os cinco isolados de cada planta se agrupam e tendem a formar clados próximos a grupos de isolados de genótipos hospedeiros similares, o que pode decorrer da interação entre a replicase viral e a planta. Para a região 3’ do genoma, houve a separação do conjunto de 75 isolados em dois grupos de variantes. A identidade nucleotídica par a par entre isolados de grupos distintos variou entre 75 e 85%. Pelos testes de seleção, existe evidência significativa de que vária populações virais estão sobre processo de seleção não neutra. O acúmulo viral não teve diferença significativa entre plantas transgênicas e convencionais. A quantificação também não revelou diferenças em níveis virais em plantas transgênicas originadas de retrocruzamentos com a cultivar Pérola em comparação aos níveis naquelas retrocruzadas com a cultivar BRS Pontal. Os resultados desse trabalho reforçam resultados anteriores de que dois grupos de estirpes de CPMMV estão distribuídos pelas regiões produtoras brasileiras, provavelmente pela presença em plantas daninhas (onde a variabilidade desse vírus nunca foi analisada) e em hospedeiros cultivados como o próprio feijoeiro. Também comprova a alta variabilidade desse vírus de RNA, principalmente nas novas cultivares de feijoeiro resistente ao mosaico dourado por transgenia. É provável que a presença de BGMV nas cultivares convencionais e consequentemente a infecção mista dos dois vírus tenha algum efeito sobre os valores de variabilidade apresentados nesse estudo. Os mecanismos moleculares dessa interação, porém, não são conhecidos. Os resultados apresentados e o fato de que hospedeiros não cultivados estão distribuídos por grandes áreas de produção e que estes podem atuar como reservatório viral, além da grande distribuição da mosca branca pelo Brasil, fazem com que novos trabalhos com esse patógeno sejam de extrema importância. / The common bean crop in Brazil, besides its economic importance, represents a major source of what is daily consumed by Brazilian population in terms of proteins and carbohydrates, contributing to food security. Cultivars with a transgenic resistance event to Bean golden mosaic virus (begomovirus), a virus that causes one of the most important diseases of common bean, were developed after many years of research. The release of these cultivars immune to BGMV is undergoing difficulties because of the re-emergence of Cowpea mild mottle virus (carlavirus) in common bean, which has raised some concerns for the researchers and the growers. Although works to access the damage potential into different genotypes of these resistant isolines and to investigate the virus distribution are being reported, no study is found evaluating CPMMV molecular characteristics and diversity in transgenic as well as conventional common bean cultivars in Brazil. In fact, there are very few studies of this kind globally. The objective of this work was to evaluate the variability on CPMMV populations from each of the fifteen common bean cultivars, ten transgenic and resistant to BGMV, and five conventional cultivars, from a field experiment with natural CPMMV transmission by whitefly. CPMMV was also quantified on the three plant replicates of each genotype. Five CPMMV isolates were completely sequenced on all fifteen plants with different genotypes, providing 75 full virus genomes after assembly of PCR sequence blocks. Differences in variability were found between those groups of isolates from transgenic plants to those from conventional ones. With the π, S, K, and Θ-W descriptors, we detected a considerable higher CPMMV variability within transgenic plants in comparison to the virus variability within conventional cultivars in most of the cases. This was the case for all analyzed ORF’s. The ORF’s 2, 3 and 4 were the ones with the highest variability in the genome; at ORF’s 2, 5, and 6, the differences in variability mentioned above are most discernible. Recombination events between isolates happening at the ORF 1 region were detected, as well as at ORF 2 and at ORF 6. Mostly of these were between isolates from transgenic plants. The phylogenetic analysis with ORF 1 sequences of all seventy-five isolates reveals the formation of groups based on host genotypes, and that these groups are most likely grouping near a cluster of isolates from a similar host plant genotype. These could be the result of the direct and specific interactions needed between the viral replicase and the plant. The results of phylogenetic analysis and sequence comparisons with the 3’ region of the viral genome (ORF 2-6), divided the 75 isolates of this study into two groups of CPMMV variants. The pairwise nucleotide differences between isolates from distinct groups ranged from 75 to 85%. The selection tests at some ORF’s give significant evidence that some populations are evolving under a non- random process. The viral accumulation on conventional cultivars did not differ statistically to the accumulation at transgenic plants. In addition, there is no evidence of differences between CPMMV levels at transgenic cultivars that have Pérola as the reccurent parent to those that have the BRS Pontal. The results from this work corroborate with previous studies that indicate the existence of two CPMMV strains naturally distributed in Brazilian production areas. It also confirms the expected high variability potential of this RNA virus; the high variability registered on the newly developed BGMV-resistant transgenic common bean cultivars is also troublesome. The presence of BGMV in mixed infections with CPMMV at conventional cultivars is probably influencing the results of CPMMV variability, but the molecular properties of this interaction is still unknown. These results, in addition to the fact that non-cultivated host plants are distributed along major production areas and may act as viral reservoirs and the known widespread of whiteflies in growing regions of Brazil, make further studies with this pathogen of fundamental importance.

BACKGROUND: Mild cognitive impairment (MCI) is a clinical condition that is characterized by mild changes in cognition. The amnestic form of MCI (aMCI) primarily affects memory and is thought to represent a stage between healthy aging and Alzheimer’s disease (AD). The medial temporal lobe (MTL) and the limbic system are two areas of the brain that have been implicated in the amnestic form of MCI. While MCI represents a risk factor for AD, it does not always lead to dementias. Being a carrier of the APOE Ɛ4 allele has also shown to increase chances of progression from MCI to AD. OBJECTIVE: To determine whether the subnuclei of the amygdala, along with other specific regions within the MTL, can differentiate between cognitively normal individuals and age-matched subjects with aMCI. METHODS: T1-weighted magnetic resonance imaging (MRI) data from two sources, the Boston University Alzheimer’s Disease Center (BU-ADC) and the Alzheimer’s Disease Neuroimaging Initiative (ADNI), was compiled for cross-sectional analysis. 95 scans in total from 45 cognitively normal participants and 50 diagnosed with aMCI were analyzed and the volumes of interest were automatically generated by the developmental version of FreeSurfer v6.0. To evaluate how well the volumes could predict either group membership (i.e. control group or MCI group) or APOE Ɛ4 status (i.e. carrier or noncarrier), the variables were assessed by nominal logistic regression models. RESULTS: Six of the nine nuclei of the amygdala had significantly reduced volumes in the aMCI group compared to controls. The whole amygdala and the perirhinal cortex also demonstrated reduced volumes in the aMCI group compared to the control group. The whole amygdala was a good predictor of group membership (R2 = 0.1386, whole model test chi square = 18.21558, p = 0.0004), but none of the subnuclei were good predictors individually. A model containing the 9 nuclei, the entorhinal cortex, and the perirhinal cortex provided a good fit for predicting APOE Ɛ4 status fit (R2 = 0.3000, whole model test chi square = 36.29563, p = 0.0002) and the best predictor was the corticoamygdaloid transition area of the amygdala. CONCLUSIONS: The results of our study confirm previous findings of reduced whole amygdala volume and add to the limited literature of reduced perirhinal cortex and amygdaloid nuclei volumes in MCI compared to healthy controls. To the best of our knowledge, this was the first time the automatic segmentation atlas was used to analyze the volumes of nine subnuclei of the amygdala in a population of aMCI. Our model testing the volume of the whole amygdala accurately predicted aMCI subjects with 58% accuracy and controls with 70% accuracy; the accuracy rose to 69% when the entorhinal cortex and the perirhinal cortex were added to the model to predict aMCI subjects from controls. Additionally, the model for predicting APOE Ɛ4 status identified noncarriers of the allele at 85% accuracy. Future studies should consider increasing the sample size to better assess small ROIs and assess for differences in the separate hemispheres.

Bakgrund: Antalet äldre i världen ökar ständigt. Åtta procent av Sveriges befolkning, som är 65 år och äldre, har någon form av kognitiv svikt. Med åldern ökar risken för mild kognitiv svikt, vilket påverkar alla områden i människans liv. Mild kognitiv svikt är ett tillstånd som kan leda till mer omfattande kognitiv nedsättning om det inte åtgärdas i ett tidigt skede. Det är därför viktigt att tidigt upptäcka och åtgärda de första symtomen på mild kognitiv svikt.  Syfte: Syftet med studien var att undersöka vilka interventioner som kan förbättra livskvaliteten hos äldre personer med mild kognitiv svikt. Metod: Systematisk blandad litteratur översikt (Systematic mixed studie review) med narrativ sammanfattning (narrativ summary) enligt Ryan (2013) valdes som studiedesign. Artiklar söktes systematiskt i databaserna Cinahl, PubMed och PsycINFO. Följande kategorier fastställdes vid analysen: fysisk aktivitet, kognitiv stimulans, kombinerade fysiska och kognitionsstimulerande interventioner och estetiska aktiviteter. Resultat: Studiens resultat baserades på en analys av elva kvantitativa och tre kvalitativa studier som omfattade äldre personer i ålder 65+ med MCI. Dessa artiklar publicerades mellan åren 2019 och 2023 och omfattade länderna Italien (1), Kanada (1), Kina (6), Mexiko (1), Nederländerna (1), Sverige (1), Tyskland (1) och USA (2). Interventioner som inkluderades i studien omfattade: fysiska aktiviteter som Tai Chi, måttlig aerob träning och squaredans; interventioner för kognitiv stimulans med hjälp av modern teknink; fysiska aktiviteter kombinerade med kognitiv träning; samt estetiska aktiviteter som stråkkonst, akvarell och akrylmålning. Interventionerna visade varierande grad av påverkan på livskvalitet för äldre personer med MCI, men samtliga visade positiv effekt på livskvaliteten. Slutsatser: Det finns evidens som tyder på att användandet av moderna teknologier kan förbättra äldre personernas med MCI livskvalitet. Interventioner som mindfulness, reminiscens, estetiska och fysiska aktiviteter kan också ge en positiv effekt på livskvalitet hos äldre personer med MCI. / Background: The number of elderly people in the world is constantly increasing. Eight percent of Sweden's population, who are 65 years and older, have some form of cognitive impairment. With age, the risk of mild cognitive impairment increases, which affects all areas of a person's life. Mild cognitive impairment is a condition that can lead to more extensive cognitive impairment if not addressed in its early stages. It is therefore important to detect and address the first symptoms of mild cognitive impairment at an early stage.  Aim: The aim of this study was to investigate which interventions can improve the quality of life in older people with mild cognitive impairment. Method: Systematic mixed study review with narrative summary according to Ryan (2013) was chosen as the study design. Articles were systematically searched in the databases Cinahl, PubMed and PsycINFO. The following categories were established in the analysis: physical activity, cognitive stimulation, combined physical and cognition-stimulating interventions, and aesthetic activities. Results: The results of the study were based on an analysis of eleven quantitative and three qualitative studies that included older people aged 65+ with MCI. These articles were published between the years 2019 and 2023 and covered the countries Italy (1), Canada (1), China (6), Mexico (1), the Netherlands (1), Sweden (1) Germany (1), and the United States (2). Interventions in the study included: physical activities such as Tai Chi, moderate aerobic, and square dancing; interventions for cognitive stimulation using modern technology; physical activities combined with cognitive training; as well as aesthetic activities such as string art, watercolor, and acrylic painting. The interventions showed varying degrees of impact on quality of life for older people with MCI, but all showed a positive effect on quality of life.  Conclusions: There is evidence to suggest that the use of modern technologies can improve the quality of life of older people with MCI. Interventions such as mindfulness, reminiscence, aesthetic and physical activities can also have a positive effect on quality of life in older people with MCI.

D. Tech. Chemical, Metallurgical and Materials Engineering / Discusses the objective of this present study is to manufacture particulate-strengthening Zn-Al-SnO2-TiO2 composite alloy on mild steel from chloride and sulphate baths with the target of improving mechanical and anti-corrosion, wear properties for automotive and decorative applications. Sub-Objectives:To study the effect of Zn-Al-SnO2-TiO2 composite properties on mild steel substrate To investigate the novel multifunctional thin films evolution formed on mild steel and their tribological properties. To investigate thermo-mechanical recrystallization behaviour and its thermal instability.To study the anti-corrosion resistance performance of the electrofabricated quaternary Zn-Al-SnO2-TiO2 coatings.To draw attention to the functional processing parameters of Zn-Al-SnO2-TiO2 produced coatings for high durability.