Background: Carriers of the APOE epsilon 4 allele are at increased risk of developing Alzheimer's disease (AD), and have been shown to have reduced cerebral metabolic rate of glucose (CMRgl) in the same brain areas frequently affected in AD. These individuals also exhibit reduced plasma levels of apolipoprotein E (apoE) attributed to a specific decrease in the apoE4 isoform as determined by quantification of individual apoE isoforms in APOE epsilon 4 heterozygotes. Whether low plasma apoE levels are associated with structural and functional brain measurements and cognitive performance remains to be investigated. Methods: Using quantitative mass spectrometry we quantified the plasma levels of total apoE and the individual apoE3 and apoE4 isoforms in 128 cognitively normal APOE epsilon 3/epsilon 4 individuals included in the Arizona APOE cohort. All included individuals had undergone extensive neuropsychological testing and 25 had in addition undergone FDG-PET and MRI to determine CMRgl and regional gray matter volume (GMV). Results: Our results demonstrated higher apoE4 levels in females versus males and an age-dependent increase in the apoE3 isoform levels in females only. Importantly, a higher relative ratio of apoE4 over apoE3 was associated with GMV loss in the right posterior cingulate and with reduced CMRgl bilaterally in the anterior cingulate and in the right hippocampal area. Additional exploratory analysis revealed several negative associations between total plasma apoE, individual apoE isoform levels, GMV and CMRgl predominantly in the frontal, occipital and temporal areas. Finally, our results indicated only weak associations between apoE plasma levels and cognitive performance which further appear to be affected by sex. Conclusions: Our study proposes a sex-dependent and age-dependent variation in plasma apoE isoform levels and concludes that peripheral apoE levels are associated with GMV, CMRgl and possibly cognitive performance in cognitively healthy individuals with a genetic predisposition to AD.

A research report submitted to the Faculty of Medicine, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Medicine in Applied Physiology. Johannesburg, 1997. / A post-exercise reduction in blood pressure (BP) may be the primary reason that athletes suffer from exerclse-assoclated collapse (EAC) at the end ot ultra-endurance running ever.s. Plasma volume decreases, possibly caused by dehydration, may be the cause of the decrease til blood pressure, In order to determine whether there is a correlation between plasma volume changes and the post-exercise BP drop, this study evaluated alterations in pre- and post-race blood pressures and changes in blood and plasma volumes, It found that compared to resting values, systolic, dlastollc and mean arterial blood pressures (mmHg) fell significantly from 119 ± 4, mean ± standard deviation, 74 ± 8, and 88 ± 5 respectively to '106 ± 14, 62 ± 12 and 77 ± 10 (ps 0,05), whereas pulse pressure failed to change, Compared to pre-race values, plasma and blood volume were found not to have changed significantly, During the race plasma urea (U) and creatinine (C) concentrations increased significantly, whereas body mass and body mass index both fell significantly. Haernatocrlt, haemoglobin, mean cell volume, red blood cell number, mean cell haemoglobin concentration, the mean cell haemoglobin, plasma sodium, potassium, chloride and protein concentrations, the U:C ratio and osmolality remained constant. There were no significClnt correlations between changes in plasma or blood volume and changes in blood pressure, These data support the Idea that a post-race decrease in blood pressure does not result primarily from an intravascular fluid loss, It is likely therefore that athletes who collapse at the end of ultraendurance races due to EAC do so as a result of 'post-exercise hypotension' secondary to venous pooling, and not as a result of a reduction in plasma volume, / MT2017

Thesis advisor: Robert Meyerhoff / Thurston showed that for all but a finite number of Dehn Surgeries on a cusped hyperbolic 3-manifold, the resulting manifold admits a hyperbolic structure. Global bounds on this number have been set, and gradually improved upon, by a number of Mathematicians until Lackenby and Meyerhoff proved the sharp bound of 10, which is realized by the figure-eight knot exterior. We improve this result by proving a stronger version of Gordon’s conjecture: that excluding the figure-eight knot exterior, cusped hyperbolic 3-manifolds have at most 8 non-hyperbolic Dehn Surgeries. To do so we make use of the work of Gabai et. al. from a forthcoming paper which parameterizes measurements of the cusp, then uses a rigorous computer aided search of the space to classify all hyperbolic 3-manifolds up to a specified cusp size. Their approach hinges on the discreteness of manifold points in the parameter space, an assumption which cannot be made if the manifolds have infinite volume. In this paper we also show that infinite-volume manifolds, which must be Free Bicuspid, can have cusp volume as low as 3.159. As such, these manifolds are a concern for any future expansion of the approach of Gabai et. al. / Thesis (PhD) — Boston College, 2018. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Mathematics.

PURPOSE: Extremely low gestation age newborns (ELGANs) are at high risk for developmental brain abnormalities, which can lead to cognitive, physical, emotional and behavioral deficits. This study is to determine potential brain volumetric abnormalities of ELGAN children at 9 to 10 years of age. METHODS: High-resolution magnetic resonance imaging (MRI) scans were obtained from 82 ELGAN children using a dual-echo turbo spin-echo (DE-TSE) pulse sequence at 3.0T (or 1.5T at only one site). The DICOM MR images were processed with quantitative MRI algorithms programmed in Mathcad. The brain gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) volumes were quantified using semi-automated clustering segmentation algorithms. RESULTS: Total brain volumes (GM+WM) of ELGAN children showed a large distribution range from 400 to 1500 mL. About 63% of the children had smaller brain volumes while 5% of them had larger brain volumes compared to the published data from normal children at the same ages1. Smaller brain volumes were observed more often in males (74%) than in females (50%). WM reduction was the major change in ELGANs with over 90% of them (86% of males and 92% of females) having reduced WM volumes. GM volumes were either reduced (15%) or enlarged (32%); GM reduction was observed more often in males (31%) than in females (4.8%), while GM enlargement was more frequently observed in females (35%) than in males (28%). Intracranial CSF volumes range from 25 mL to 600 mL, with 16% of ELGAN children (9% of males and 21% of females) having smaller CSF volume, while 38% of them (53% of males and 27% of females) having larger CSF volume. Correlation analysis revealed a positive correlation between total intracranial matter (ICM) and CSF volumes (male: r = 0.4972, p = 0.0014 and female: r = 0.3233, p = 0.0125), but a negative correlation was found between brain volumes and CSF volumes (male: r = - 0.2998, p = 0.0424 and female: r = - 0.2279, p = 0.0596). Further analysis demonstrated a negative correlation between GM and CSF both in absolute (male: r = - 0.4489, p = 0.0039 and female: r = - 0.3769, p = 0.0041) and in relative (male: r = - 0.8675, p = 0.0000 and female: r = - 0.8350, p = 0.0000) volumes, while WM volumes did not correlate with CSF volumes. CONCLUSION: ELGAN children had mostly smaller brain volumes while some of them displayed larger brain volumes at ages of 9 to 10 years. The reduction of WM was a characteristic change in ELGAN children and contributed to smaller brain volumes. GM volumes either increased or decreased. Larger intracranial CSF volumes were associated with larger intracranial matter (ICM) volume.

Alcoholism has been linked to cognitive, behavioral, and emotional defects, and damage to the cerebellum has been associated with aspects of these impairments. However, little is known about the role of damage to specific cerebellar subregions in the deficits, nor about possible gender differences in alcoholism-related cerebellar abnormalities. In this study, volumetric analyses of specific cerebellar regions were performed in relation to the interactions of alcoholism, gender, and measures of drinking history. Structural brain scans of 44 alcoholics (23 men) and 39 nonalcoholic controls (18 men) were obtained using T1 magnetic resonance imaging at 3T. Scans were manually labeled according to cerebellar features, using methodology developed at the Center for Morphometric Analyses, Massachusetts General Hospital, Boston. Each lobule was parcellated and mediolateral divisions were delineated. In addition to measuring total cerebellar gray and white matter, along with the anterior and posterior lobes, we also measured volumes for a priori regions of interest that have been shown to correspond to functions impaired in alcoholism: emotion, executive functions, working memory, motor abilities, and spatial abilities. Total cerebellar white matter volume was observed to be smaller in alcoholic than in nonalcoholic participants, but this difference was not observed for total gray matter volume. Moreover, the volumes of the cortical parcellation units we selected varied with drinking history, including negative associations between (a) years of heavy drinking, and (b) volumes of the anterior and flocculonodular lobes, and of the spinocerebellar region. The negative association between anterior volume and years of heavy drinking was driven primarily by alcoholic men. Additionally, we observed that white and gray cerebellar volumes for alcoholic women were significantly larger than for alcoholic men, but this pattern of gender differences was not significant for the control group. The identification of drinking-related abnormalities in cerebellar subregions builds upon prior findings in other regions of the brain, and lays a foundation that can be utilized to inform how cerebro-cerebellar networks are perturbed in this pathological condition. The results also provide estimates of how individual differences in drinking history can predict cerebellar volumes, and how the impact of drinking differs for men and women.

Made available in DSpace on 2018-08-01T23:29:06Z (GMT). No. of bitstreams: 1 tese_10780_45 - Ricardo Pessoti Garuzzi.pdf: 14959914 bytes, checksum: 49aefda0e6ae1cb2f3fc9b4be3a0a01f (MD5) Previous issue date: 2017-03-08 / A energia solar fotovoltaica é uma opção bastante atrativa, entretanto ainda é cara se comparada com as fontes tradicionais. Uma forma de tornar a fabricação da célula solar fotovoltaica mais competitiva no mercado é diminuindo a quantidade de material utilizado. A diminuição da espessura encontra limites físicos e operacionais associados com o método de deposição. Um deles, e que é objeto de estudo neste trabalho, é o limite de vazão mínima (low-flow limit). Este trabalho apresenta a simulação numérica do processo de revestimento por extrusão de fluidos newtoniano, não-newtoniano e newtoniano com partículas utilizando a técnica VOF (Volume Of Fluid) para determinar o limite de vazão mínima deste processo. No caso de newtoniano com partículas além do VOF é utilizada a técnica DPM (Discrete Phase Model). O domínio de solução das equações governantes no plano bidimensional se restringe a parte à jusante da barra de revestimento. Como resultados tem-se que o aumento do número de capilaridade resulta em um aumento da espessura mínima, e com o aumento da importância do comportamento não-newtoniano a espessura mínima de filme diminui. Para as partículas tem-se uma análise da sua concentração, com a ocorrência de um problema de alta quantidade na região do revestimento, sendo desejado que ocorra na região de interesse do filme depositado. Os trabalhos relacionados ao escoamento com fluido newtoniano foram publicados em duas revistas, como mostra os APÊNDICE A e APÊNDICE B. Além disso foi realizada uma análise econômica, também publicada, como pode ser visto no APÊNDICE C, e os detalhes constam no APÊNDICE E: GESTÃO FINANCEIRA.

M-theory, a generalization of string theory, motivates the search for examples of volume minimizing cycles in Riemannian manifolds of G2 holonomy. Methods of calibrated geometry lead to a system of four coupled nonlinear partial differential equations whose solutions correspond to associa- tive submanifolds of R7, which are 3-dimensional and minimize volume in their real homology classes. Several approaches to finding new solutions are investigated, the most interesting of which exploits the quaternionic structure of the PDE system. A number of examples of associative 3-planes are explicitly given; these may possibly be projected to nontrivial volume minimizing cycles in, for example, the G2-manifold R6 × S1.

Orientador: Sergio Marrone Ribeiro / Resumo: A medida correta e acurada do volume pulmonar é uma importante ferramenta de avaliação diagnóstica e terapêutica na prática clínica. Atualmente, com o avanço da capacidade de reconstrução tridimensional da Tomografia Computadorizada (TC) é possível mensurar o volume pulmonar total por este aparelho. O presenta trabalho busca apresentar uma nova técnica de mensuração do volume pulmonar e estabelecer uma padronização de valores normais do volume pulmonar na população adulta. O volume pulmonar total de 95 pacientes, assim como quatro medidas antropométricas obtidas na TC foram analisados. Em um intervalo de confiança de 95%, se estabeleceu os limites inferiores e superiores da relação entre o volume e cada uma das medidas, assim valores de importância estatística. / Abstract: Correct and accurate measurement of lung volume is an important diagnostic and therapeutic evaluation tool in clinical practice. Nowadays, with the advancement of the capacity of three-dimensional reconstruction of Computed Tomography (CT), it is possible to measure the total lung volume by this device. The present paper aims to present a new technique for measuring lung volume and establish a standardization of normal values of lung volume in the adult population. The total lung volume of 95 patients, as well as four anthropometric measurements obtained at CT were analyzed. In a 95% confidence interval, we established the lower and upper limits of the relationship between the volume and each of the measures, thus values of statistical importance. / Mestre

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