569 research outputs found
Willmore surfaces and Hopf tori in homogeneous 3-manifolds
Some classification results for closed surfaces in Berger spheres are presented. On the one hand, a Willmore functional for isometrically immersed surfaces into an homogeneous space E3(κ,τ) with isometry group of dimension 4 is defined and its first variational formula is computed. Then, we characterize Clifford and Hopf tori as the only Willmore surfaces satisfying a sharp Simons-type integral inequality. On the other hand, we also obtain some integral inequalities for closed surfaces with constant extrinsic curvature in E3(κ,τ), becoming equalities if and only if the surface is a Hopf torus in a Berger sphere
Granulocytic sarcoma of the oral cavity in a chronic myeloid leukemia patient : an unusual presentation
Intraoral granulocytic sarcoma is an unusual manifestation of chronic or acute leukemia. The oral manifestations often involve enlargements of the gingival and mucosal tissue from direct leukemic cell infiltration. Only 38 cases have been reported in scientific literature to date. We present the case of a 47 year-old female who was diagnosed with chronic myeloid leukemia (CML) in December 2006. She was referred to a dentist for further evaluation, revealing generalized gingival overgrowth as well as periodontal, apical disease, and bleeding of the gums. An oral biopsy was performed and histological features revealed immature blast-like cells
Characterizations of complete linear Weingarten spacelike submanifolds in a locally symmetric semi-Riemannian manifold
In this paper, we deal with n-dimensional complete spacelike submanifolds Mn with flat normal bundle and parallel normalized mean curvature vector immersed in an (n + p)-dimensional locally symmetric semi-Riemannian manifold L_p^(n+p) of index p obeying some standard curvature conditions which are naturally satisfied when the ambient space is a semi-Riemannian space form. In this setting, we establish sufficient conditions to guarantee that, in fact, p = 1 and Mⁿ is isometric to an isoparametric hypersurface of L_1^(n+1)having two distinct principal curvatures, one of which is simple.The first author is partially supported by CAPES, Brazil. The second author is partially supported by CNPq, Brazil, grant 303977/2015- 9. The fourth author is partially supported by CNPq, Brazil, grant 308757/2015-7.peerReviewe
Sharp upper estimates for the first eigenvalue of a Jacobi type operator
Our purpose in this article is to obtain sharp upper estimates for the first positive eigenvalue of a Jacobi type operator, which is a suitable extension of the linearized operators of the higher order mean curvatures of a closed hypersurface immersed either in the Euclidean space or in the Euclidean sphere.Brazilian National Research Council (CNPq): grant 303977/2015-9 y grant 308757/2015-7.peerReviewe
IL-1β, TNF-α, TGF-β, and bFGF expression in bone biopsies before and after parathyroidectomy
IL-1β, TNF-α, TGF-β, and b FGF expression in bone biopsies before and after parathyroidectomy.BackgroundThere is growing evidence pointing to an involvement of cytokines and growth factors in renal osteodystrophy. In this study, the expression of interleukin-lβ (IL-1β), tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), and basic fibroblast growth factor (bFGF) in bone biopsies taken from uremic patients before and 1 year after parathyroidectomy (PTX) was evaluated. Biochemical features and histomorphometric outcome were also studied.MethodsIliac bone biopsies were taken before and 1 year after PTX in nine uremic patients with severe hyperparathyroidism (HPT). Immunohistochemical techniques were used to identify the expression of IL-1β, TNF-α, TGF-β, and bFGF in these bone samples.ResultsAt the time of the second bone biopsy, the mean serum total alkaline phosphatase activity was normal, whereas mean serum intact parathyroid hormone (iPTH) level was slightly above the upper limit of normal values. Histomorphometric analysis showed a decrease in resorption parameters and static bone formation parameters after PTX. Dynamically, mineral apposition rate (MAR) and mineralization surface (MS/BS) decreased significantly. There was a marked local expression of IL-1β, TNF-α, TGF-β, and bFGF in bone biopsies before PTX, particularly in fibrous tissue and resorption areas. One year after PTX, IL-1β decreased from 23.6 ± 7.5% to 9.9 ± 3.1%, TNF-α from 4.5 ± 1.5% to 0.7 ± 0.8%, TGF-β from 49.6 ± 9.8% to 15.2 ± 4.6%, and bFGF from 50.9 ± 12.7% to 12.9 ± 7.9% (P < 0.001). A significant correlation was documented between cytokines and growth factors expression in bone with iPTH levels before and after PTX (P < 0.05).ConclusionsBased on these results, we suggest that IL-1β, TNF-α, TGF-β, and bFGF are involved in bone remodeling regulation, acting as local effectors, possibly under the control of PTH
Sharp upper estimates for the first eigenvalue of a Jacobi type operator
Our purpose in this article is to obtain sharp upper estimates for the first positive eigenvalue of a Jacobi type operator, which is a suitable extension of the linearized operators of the higher order mean curvatures of a closed hypersurface immersed either in the Euclidean space or in the Euclidean sphere.Brazilian National Research Council (CNPq): grant 303977/2015-9 y grant 308757/2015-7.peerReviewe
Contribution of mixing to upward transport across the tropical tropopause layer (TTL)
During the second part of the TROCCINOX campaign that took place in Brazil in early 2005, chemical species were measured on-board the high-altitude research aircraft Geophysica (ozone, water vapor, NO, NOy, CH4 and CO) in the altitude range up to 20 km (or up to 450 K potential temperature), i.e. spanning the entire TTL region roughly extending between 350 and 420 K. Here, analysis of transport across the TTL is performed using a new version of the Chemical Lagrangian Model of the Stratosphere (CLaMS). In this new version, the stratospheric model has been extended to the earth surface. Above the tropopause, the isentropic and cross-isentropic advection in CLaMS is driven by meteorological analysis winds and heating/cooling rates derived from a radiation calculation. Below the tropopause, the model smoothly transforms from the isentropic to the hybrid-pressure coordinate and, in this way, takes into account the effect of large-scale convective transport as implemented in the vertical wind of the meteorological analysis. As in previous CLaMS simulations, the irreversible transport, i.e. mixing, is controlled by the local horizontal strain and vertical shear rates. Stratospheric and tropospheric signatures in the TTL can be seen both in the observations and in the model. The composition of air above ≈350 K is mainly controlled by mixing on a time scale of weeks or even months. Based on CLaMS transport studies where mixing can be completely switched off, we deduce that vertical mixing, mainly driven by the vertical shear in the tropical flanks of the subtropical jets and, to some extent, in the the outflow regions of the large-scale convection, offers an explanation for the upward transport of trace species from the main convective outflow at around 350 K up to the tropical tropopause around 380 K
Contribution of mixing to the upward transport across the TTL
During the second part of the TROCCINOX campaign that took place in Brazil in early 2005, chemical species were measured on-board of the high altitude research aircraft Geophysica (ozone, water vapor, NO, NOy, CH4 and CO) in the altitude range up to 20 km (or up to 450 K potential temperature), i.e. spanning the TTL region roughly extending between 350 and 420 K.
Analysis of transport across TTL is performed using a new version of the Chemical Lagrangian Model of the Stratosphere (CLaMS). In this new version, the stratospheric model has been extended to the earth surface. Above the tropopause, the isentropic and cross-isentropic advection in CLaMS is driven by ECMWF winds and heating/cooling rates derived from a radiation calculation. Below the tropopause the model smoothly transforms from the isentropic to hybrid-pressure coordinate and, in this way, takes into account the effect of large-scale convective transport as implemented in the ECMWF vertical wind. As with other CLaMS simulations, the irreversible transport, i.e. mixing, is controlled by the local horizontal strain and vertical shear rates.
Stratospheric and tropospheric signatures in the TTL can be seen both in the observation and in the model. The composition of air above ≈350 K is mainly controlled by mixing on a time scale of weeks or even months. Based on CLaMS transport studies where mixing can be completely switched off, we deduce that vertical mixing, mainly driven by the vertical shear in the outflow regions of the large-scale convection and in the vicinity of the subtropical jets, is necessary to understand the upward transport of the tropospheric air from the main convective outflow around 350 K up to the tropical tropopause around 380 K. This mechanism is most effective if the outflow of the mesoscale convective systems interacts with the subtropical jets
Contribution of mixing to the upward transport across the TTL
During the second part of the TROCCINOX campaign that took place in Brazil in early 2005, chemical species were measured on-board of the high altitude research aircraft Geophysica (ozone, water vapor, NO, NOy, CH4 and CO) in the altitude range up to 20 km (or up to 450 K potential temperature), i.e. spanning the TTL region roughly extending between 350 and 420 K.
Analysis of transport across TTL is performed using a new version of the Chemical Lagrangian Model of the Stratosphere (CLaMS). In this new version, the stratospheric model has been extended to the earth surface. Above the tropopause, the isentropic and cross-isentropic advection in CLaMS is driven by ECMWF winds and heating/cooling rates derived from a radiation calculation. Below the tropopause the model smoothly transforms from the isentropic to hybrid-pressure coordinate and, in this way, takes into account the effect of large-scale convective transport as implemented in the ECMWF vertical wind. As with other CLaMS simulations, the irreversible transport, i.e. mixing, is controlled by the local horizontal strain and vertical shear rates.
Stratospheric and tropospheric signatures in the TTL can be seen both in the observation and in the model. The composition of air above ≈350 K is mainly controlled by mixing on a time scale of weeks or even months. Based on CLaMS transport studies where mixing can be completely switched off, we deduce that vertical mixing, mainly driven by the vertical shear in the outflow regions of the large-scale convection and in the vicinity of the subtropical jets, is necessary to understand the upward transport of the tropospheric air from the main convective outflow around 350 K up to the tropical tropopause around 380 K. This mechanism is most effective if the outflow of the mesoscale convective systems interacts with the subtropical jets
Purification and Preliminary Crystallographic Analysis of a New Lys49-PLA2 from B. Jararacussu
BjVIII is a new myotoxic Lys49-PLA2 isolated from Bothrops jararacussu venom that exhibits atypical effects on human platelet aggregation. To better understand the mode of action of BjVIII, crystallographic studies were initiated. Two crystal forms were obtained, both containing two molecules in the asymmetric unit (ASU). Synchrotron radiation diffraction data were collected to 2.0 Å resolution and 1.9 Å resolution for crystals belonging to the space group P212121 (a = 48.4 Å, b = 65.3 Å, c = 84.3 Å) and space group P3121 (a = b = 55.7 Å, c = 127.9 Å), respectively. Refinement is currently in progress and the refined structures are expected to shed light on the unusual platelet aggregation activity observed for BjVIII
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