992 resultados para Free-form
Resumo:
The objective of this study was to investigate the relationship between the physical activity (PA) and its related variables under confinement and in free-living conditions in Asian individuals, where no such information presently exists. The subjects consisted of eighty-six Japanese individuals with a mean age of 38+/-12 years. Under confinement in a large respiratory chamber, the energy expenditure (EE) was measured for 24h. In addition, two moderate walking exercises of 30 min each on a horizontal treadmill were assigned. Free-living measurements of 7 days were also performed using a validated accelerometer. The PA level in the chamber (1.47+/-0.11), expressed as a multiple of the basal EE, was lower than that in free-living conditions (1.53+/-0.12) (p<0.001). However, the two values were closely correlated (r=0.744, p<0.001). Conversely, a residual analysis showed a wide variation in the mean difference for both conditions and revealed a significant systematic error (r=-0.548, p<0.001), thus indicating an increased gap with increasing PA levels in free-living conditions. Similar results were obtained following the exclusion of the imposed exercise sessions. In contrast, the daily step counts under both conditions did not show any correlation. The PA level in the chamber (including and excluding imposed walking exercises) is compatible with the PA level in free-living conditions at the group level, although the daily step counts are unrelated. Thus, the PA level in the chamber may provide valuable information to help us achieve a better understanding of human PA in daily life as it is related to behavioral research.
Resumo:
RATIONALE AND OBJECTIVES: The purpose of this study was the investigation of the impact of real-time adaptive motion correction on image quality in navigator-gated, free-breathing, double-oblique three-dimensional (3D) submillimeter right coronary magnetic resonance angiography (MRA). MATERIALS AND METHODS: Free-breathing 3D right coronary MRA with real-time navigator technology was performed in 10 healthy adult subjects with an in-plane spatial resolution of 700 x 700 microm. Identical double-oblique coronary MR-angiograms were performed with navigator gating alone and combined navigator gating and real-time adaptive motion correction. Quantitative objective parameters of contrast-to-noise ratio (CNR) and vessel sharpness and subjective image quality scores were compared. RESULTS: Superior vessel sharpness, increased CNR, and superior image quality scores were found with combined navigator gating and real-time adaptive motion correction (vs. navigator gating alone; P < 0.01 for all comparisons). CONCLUSION: Real-time adaptive motion correction objectively and subjectively improves image quality in 3D navigator-gated free-breathing double-oblique submillimeter right coronary MRA.
Resumo:
Malondialdehyde (MDA) is a small reactive molecule which occurs ubiqui¬tous among eukaryotes. Interest in this molecule stems from the fact that it can be highly reactive. In green tissues of plants it is apparently formed pre¬dominantly by reactive oxygen species (ROS)-mediated non-enzymatic oxi¬dation (nLPO) of triunsaturated fatty acids (TFAs). MDA which is formed by nLPO is widely used as a disease marker and is regarded to be a cel-lular toxin. Surprisingly, sites of ROS production like mitochondria and chloroplasts possess membranes which are enriched in nLPO-prone polyun¬saturated fatty acids (PUFAs). In this work we showed that chloroplasts are the major site of MDA production in leaves of adult Arabidopsis thaliana plants, whereas analyses in seedlings revealed accumulation in meristematic tissues like the root tip, lateral roots and the apical meristem region. Char-acterizing the MDA pools in more detail, we could show that MDA in plants was predominantly present in a free, non-reactive enolate form. This might explain why it is tolerated in sites where its protonated form could poten¬tially damage the genome and proteome. Analyzing the biological fate of MDA in leaves using labeled MDA-isotopes. we were able to show that MDA is metabolized and used to assemble lipids. The major end-point metabolite was identified as 18:3-16:3-monqgalactosyldiacylglycerol (MGDG), which is the most abundant lipid in chloroplasts. We hypothesize that PUFAs in sites of ROS production, like at PS II in chloroplasts, might act as buffers pre¬venting damage of proteins, thereby generating molecules such as MDA. The MDA produced in this way appears predominantly in a non-reactive enolate form in the cell until it fulfills a biological function or until it is metabo¬lized in order to assemble polyunsaturated MGDGs. Additionally, nLPO has been reported to increase in pathogenesis and we challenged seedlings and adult plants with necrotrophic fungi. Monitoring MDA during the in¬fections, we found MDA pools in seedlings were highly inducible although they were tightly controlled in the leaves of adult plants. - Malondialdehyde (MDA) est une petite molecule réactive présente de manière ubiquitaire dans les eucaryotes. L'intérêt de cette molécule vient du fait que celle-ci pourrait être très réactive. Dans les tissus verts des plantes, la majorité du MDA est apparement formée par l'oxydation non-enzymatique (nLPO) des acides gras polyinsaturés (PUFAs) transmis par des espèces ac¬tives d'oxygène (ROS). Le MDA formé par nLPO est souvent utilisé comme marqueur de maladies et il est considéré comme une toxine cellulaire. Etonnament, les sites de production comme les mitochondries et les chloro- plastes sont riches en PUFAs qui sont sensibles à la nLPO. Dans cette thèse nous montrons que les chloroplastes répresentent le site de production de MDA dans les feuilles adultes d'Arabidopsis thaliana. Les analyses de MDA dans les plantules ont révélé que le MDA s'accumule dans les tissus meris- tematiques comme celles de la pointe de la racine, des racines latéralles et du meristème apical. Par la caractérisation du MDA présent nous avons pu montrer que la majorité du MDA était présent sous la forme d'un énolate non-réactif. Ceci pourrait expliquer pourquoi le MDA est toléré dans les sites où il pourrait casser le genome ou le protéome s'il est présent sous sa forme protonée. Les analyses du devenir du MDA dans les feuilles par des isotopes du MDA ont montré que celui-ci est metabolisé et utilisé pour assembler des lipides. Le lipide majoritairement métabolisé a été identifié comme étant le 18:3-16:3-monogalactosyldiacylglycerole (MGDG); le lipide le plus abondant dans les chloroplastes. Nous supposons que la présence des PUFAs dans les sites de production du ROS, tout comme le PS II dans les chloroplastes, pourrait jouer un rôle de tampon pour prevenir les protéines de différentes dégradations et ainsi générer des molécules telle que le MDA. La majorité du MDA produit par cette réaction est présente dans la cellule sous la forme d'énolate non-réactif, jusqu'au moment de son utilisation ou lorsqu'il serra metabolisé pour produire des MGDGs polyinsaturés. De plus, il a été décrit que nLPO pourait augmenter dans la pathogenèse, et nous avons testé des plantes adultes et des plantules en présence de champignons nécrotrophiques. L'observation du MDA pendant les infections a montré que les concentrations en MDA sont fortement induites dans les plantules mais contrôlées dans les plantes adultes.
Resumo:
Prominin-1 (CD133) is physiologically expressed at the apical membranes of secretory (serous and mucous) and duct cells of major salivary glands. We investigated its expression in various human salivary gland lesions using two distinct anti-prominin-1 monoclonal antibodies (80B258 and AC133) applied on paraffin-embedded sections and characterized its occurrence in saliva. The 80B258 epitope was extensively expressed in adenoid cystic carcinoma, in lesser extent in acinic cell carcinoma and pleomorphic adenoma, and rarely in mucoepidermoid carcinoma. The 80B258 immunoreactivity was predominately detected at the apical membrane of tumor cells showing acinar or intercalated duct cell differentiation, which lined duct- or cyst-like structures, and in luminal secretions. It was observed on the whole cell membrane in non-luminal structures present in the vicinity of thin-walled blood vessels and hemorrhagic areas in adenoid cystic carcinoma. Of note, AC133 labeled only a subset of 80B258-positive structures. In peritumoral salivary gland tissues as well as in obstructive sialadenitis, an up-regulation of prominin-1 (both 80B258 and AC133 immunoreactivities) was observed in intercalated duct cells. In most tissues, prominin-1 was partially co-expressed with two cancer markers: carcinoembryonic antigen (CEA) and mucin-1 (MUC1). Differential centrifugation of saliva followed by immunoblotting indicated that all three markers were released in association with small membrane vesicles. Immuno-isolated prominin-1-positive vesicles contained CEA and MUC1, but also exosome-related proteins CD63, flotillin-1, flotillin-2 and the adaptor protein syntenin-1. The latter protein was shown to interact with prominin-1 as demonstrated by its co-immunoisolation. A fraction of saliva-associated prominin-1 appeared to be ubiquitinated. Collectively, our findings bring new insights into the biochemistry and trafficking of prominin-1 as well as its immunohistochemical profile in certain types of salivary gland tumors and inflammatory diseases.
Resumo:
We develop a method to obtain first-passage-time statistics for non-Markovian processes driven by dichotomous fluctuations. The fluctuations themselves need not be Markovian. We calculate analytic first-passage-time distributions and mean first-passage times for exponential, rectangular, and long-tail temporal distributions of the fluctuations.
Resumo:
We show that the solution published in the paper by Senovilla [Phys. Rev. Lett. 64, 2219 (1990)] is geodesically complete and singularity-free. We also prove that the solution satisfies the stronger energy and causality conditions, such as global hyperbolicity, the strong energy condition, causal symmetry, and causal stability. A detailed discussion about which assumptions in the singularity theorems are not satisfied is performed, and we show explicitly that the solution is in accordance with those theorems. A brief discussion of the results is given.
Resumo:
Random scale-free networks have the peculiar property of being prone to the spreading of infections. Here we provide for the susceptible-infected-susceptible model an exact result showing that a scale-free degree distribution with diverging second moment is a sufficient condition to have null epidemic threshold in unstructured networks with either assortative or disassortative mixing. Degree correlations result therefore irrelevant for the epidemic spreading picture in these scale-free networks. The present result is related to the divergence of the average nearest neighbors degree, enforced by the degree detailed balance condition.
Resumo:
PURPOSE: To describe methods and outcomes of excisional revision of a filtering bleb (bleb revision) using free conjunctival autologous graft either for bleb repair or for bleb reduction after trabeculectomy and deep sclerectomy with an implant. METHODS: Retrospective medical records were reviewed for a consecutive non-comparative case series comprising patients who underwent excisional revision of a filtering bleb between May 1998-January 2001. Excisional revision using free conjunctival autologous graft (bleb revision) was performed either for bleb repair, to treat early and late leaks and hypotony with maculopathy, or for bleb reduction, to improve ocular pain, discomfort, burning, foreign body sensation, tearing, and fluctuations of visual acuity. The revision consisted of bleb excision and free conjunctival autologous graft. The bleb histopathology was analyzed in patients who underwent bleb repair. RESULTS: Sixteen patients were included in the study, consisting of nine patients who had a trabeculectomy and seven patients who had a deep sclerectomy with an implant. Bleb revision was necessary in 14 patients due to leaking filtering bleb (bleb repair), and in 2 patients due to bleb dysesthesia (bleb reduction). After a follow-up of 15.1 +/- 8.4 months, the mean intraocular pressure (IOP) rose from 7.8 +/- 6.3 mm Hg to 14.3 +/- 6.5 mm Hg, and the visual acuity from 0.4 +/- 0.3 to 0.7 +/- 0.3, with a P value of 0.008 and 0.03, respectively. The complete success rate at 32 months, according to the Kaplan-Meier survival curve, was 38.3%, and the qualified success rate was 83.3%. Four patients (25%) required additional suturing for persistent bleb leak. To control IOP, antiglaucoma medical therapy was needed for six patients (37.5%) and repeated glaucoma surgery was needed for one patient. CONCLUSION: Free conjunctival autologous graft is a safe and successful procedure for bleb repair and bleb reduction. However, patients should be aware of the postoperative possibility of requiring medical or surgical intervention for IOP control after revision.
Resumo:
We obtain the exact analytical expression, up to a quadrature, for the mean exit time, T(x,v), of a free inertial process driven by Gaussian white noise from a region (0,L) in space. We obtain a completely explicit expression for T(x,0) and discuss the dependence of T(x,v) as a function of the size L of the region. We develop a new method that may be used to solve other exit time problems.
Resumo:
We study the motion of an unbound particle under the influence of a random force modeled as Gaussian colored noise with an arbitrary correlation function. We derive exact equations for the joint and marginal probability density functions and find the associated solutions. We analyze in detail anomalous diffusion behaviors along with the fractal structure of the trajectories of the particle and explore possible connections between dynamical exponents of the variance and the fractal dimension of the trajectories.
Resumo:
The mission of the Iowa Civil Rights Commission is to end discrimination within the state of Iowa. To achieve this goal, the ICRC must effectively enforce the Iowa Civil Rights Act. The ICRA will be as effective as the Commission is in processing complaints of discrimination. The ICRC undertook significant steps forward in improving the timeliness and competency by which complaints of discrimination are processed. The screening unit was increased with special emphasis on improving the quality and quantity of the analysis of the initial screening decisions. The investigative process for nonhousing cases was completely overhauled. The improved process builds on the screening decision and focuses on the issues raised in that decision. The new process will help the ICRC reduce a significant backlog for non-housing cases. Additionally, we revamped the mediation program by moving to an allvolunteer mediation program. Over 20 Iowa lawyers volunteered to help the ICRC resolve complaints through alternative dispute resolution.