14,622 research outputs found
Efeitos cardiovasculares e antioxidantes do tratamento crônico com extrato hidroalcoólico de romã (punica granatum) em ratas hipertensas
RESUMO
O aumento da incidência de doenças cardiovasculares em mulheres coincide com a perda da função ovariana, o que sugere efeitos benéficos dos hormônios sexuais femininos e justificaria o uso de terapia hormonal após a menopausa. É crescente o número de estudos utilizando terapias alternativas naturais, com os efeitos benéficos similares aos estrogênios. Uma dessas substâncias é a Punica granatum, popularmente conhecida como romã. Contudo, os efeitos desse tratamento sobre o sistema cardiovascular na hipertensãos ainda não foram elucidados. Para tanto, nosso objetivo foi avaliar os efeitos cardiovasculares e antioxidantes do tratamento com romã em ratas hipertensas (SHR) e ovariectomizadas. Utilizamos fêmeas SHR, com 4 semanas de idade, que foram divididas em Sham e Ovariectomizada (Ovx) e subdivididas e tratadas com extrato da romã (250 mg/Kg) ou água filtrada (veículo), por 30 dias, por gavagem. Ao final do tratamento, quando os animais apresentavam 8 semanas de idade a pressão arterial sistólica foi avaliada por pletismografia de cauda. Em seguida, os animais foram pesados e eutanasiados, o sangue coletado para análise bioquímica. O coração era removido e perfundido de acordo com método de Langendorff. Após a estabilização da pressão de perfusão coronariana (PPC), foi realizada curva dose resposta de bradicinina (BK) seguida pela inibição com L-NAME. Os coxins de gordura e útero foram removidos e pesados. Para o protocolo de western blot e malondialdeído (MDA), os animais foram eutanasiados, plasma coletado e coração imediatamente removido para dissecção de coronárias. Dados foram expressos como média ± EPM. Para as comparações entre grupos utilizamos ANOVA 1 via, seguido de post hoc de Tukey ou Fisher. Para curva de bradicinina ANOVA 2 vias, seguido de post hoc Bonferroni (p <0,05). Observamos que houve redução significante da PAS em ambos os grupos tratados (Sham Água, 170 ± 3,6 mmHg, Sham Romã, 151 ± 2,5 mmHg, OVX Água, 165 ± 3,4 mmHg e OVX Romã, 151 ± 2,5 mmHg). A PPC basal foi reduzida somente no grupo Sham Romã (Sham Água 137 ± 5,8 mmHg e Sham Romã 110 ± 4,7 mmHg). Observamos que a vasodilatação no leito coronariano em resposta à bradicinina foi significativamente maior nos grupos tratados, tanto Sham como OVX. A inibição com L-NAME aboliu o relaxamento induzido pela BK em todos os grupos, mostrando que este é um efeito dependente de NO. Na expressão das enzimas, observamos aumento da SOD no grupo OVX (OVX Água, 0,8199±0,091 e OVX Romã, 1,307±0,124) e não houve alterações na catalase e eNOS. Contudo, após a
ovariectomia houve redução da eNOS (OVX Água, 0,682±0,078 e OVX Romã, 0,980±0,107) e gp91phox (OVX Água, 0,593±0,083 e OVX Romã, 0,733±0,071). Houve redução nos níveis de MDA no grupo Sham (Sham Água 16,3±2,1 nmol/mL e Sham Romã 8,1±0,9 nmol/mL), indicando diminuição do estresse oxidativo. Observamos redução nos níveis de colesterol total e de LDL no grupo Sham após tratamento (CT: 38,9 ± 2,9 mg/dL e LDL: 14,0 ± 0,6 mg/dL) comparado ao veículo (CT: 54,3 ± 5,4 mg/dL e LDL: 20,9 ± 1,5 mg/dL). No grupo OVX, houve redução nos níveis de triglicerídeos e LDL após tratamento (TG: 37 ± 3,1 mg/dL e LDL: 18,2 ± 1,5 mg/dL) comparado ao veículo (CT: 64,8 ± 4,5 mg/dL e LDL: 24,3 ± 1,7 mg/dL). Não houve redução nos níveis de HDL. Além destes efeitos, verificamos aumento nos níveis de estrogênio somente no grupo OVX tratado (OVX Água, 7,2 ± 2,0 pg/mL e OVX Romã, 61,8 ± 8,1 pg/mL) e de progesterona em ambos os grupos tratados com o extrato de romã. Observamos ainda que o tratamento promoveu aumento no peso do grupo OVX e não alterou o peso relativo do útero em ambos os grupos. Além disso, o tratamento aumentou o peso de todos os coxins de gordura em ambos os grupos, exceto a mesentérica que ficou aumentada somente no grupo OVX. Desse modo, nós sugerimos o papel terapêutico do extrato da romã sobre o sistema cardiovascular, uma vez que foi demonstrado que a redução da pressão arterial, a melhora no relaxamento e no perfil lipídico podem estar associados a uma redução no estresse oxidativo
Truncated long-range percolation on oriented graphs
We consider different problems within the general theme of long-range
percolation on oriented graphs. Our aim is to settle the so-called truncation
question, described as follows. We are given probabilities that certain
long-range oriented bonds are open; assuming that the sum of these
probabilities is infinite, we ask if the probability of percolation is positive
when we truncate the graph, disallowing bonds of range above a possibly large
but finite threshold. We give some conditions in which the answer is
affirmative. We also translate some of our results on oriented percolation to
the context of a long-range contact process.Comment: 9 pages, 1 figur
Phenolic compounds and organic acids evaluation on red grapes used for winemaking in the Northeast of Brazil.
Monitoring maturation to determine harvest time is very important to determine the enological potential and the quality characteristics and typicality of the wines (Borghezan et al., 2011). Considering that there is no cold weather in the São Francisco Valley, it is possible to scale and production of two harvests per year. This study aimed to determine the chemical composition of the ?Syrah? and ?Tempranillo? grapes, during maturation. Sixty plants were used for each cultivar, divided into three blocks
Accelerating Cold Dark Matter Cosmology ()
A new kind of accelerating flat model with no dark energy that is fully
dominated by cold dark matter (CDM) is investigated. The number of CDM
particles is not conserved and the present accelerating stage is a consequence
of the negative pressure describing the irreversible process of gravitational
particle creation. A related work involving accelerating CDM cosmology has been
discussed before the SNe observations [Lima, Abramo & Germano, Phys. Rev. D53,
4287 (1996)]. However, in order to have a transition from a decelerating to an
accelerating regime at low redshifts, the matter creation rate proposed here
includes a constant term of the order of the Hubble parameter. In this case,
does not need to be small in order to solve the age problem and the
transition happens even if the matter creation is negligible during the
radiation and part of the matter dominated phase. Therefore, instead of the
vacuum dominance at redshifts of the order of a few, the present accelerating
stage in this sort of Einstein-de Sitter CDM cosmology is a consequence of the
gravitational particle creation process. As an extra bonus, in the present
scenario does not exist the coincidence problem that plagues models with
dominance of dark energy. The model is able to harmonize a CDM picture with the
present age of the universe, the latest measurements of the Hubble parameter
and the Supernovae observations.Comment: 9 pages, 6 figures, typos corrected, references added, discussion in
Appendix B extende
Novos registros de hospedeiros de Anastrepha striata Schiner (Diptera: Tephritidae) no estado do Amapa, Brasil.
Resumo 109
Inflationary Models Driven by Adiabatic Matter Creation
The flat inflationary dust universe with matter creation proposed by
Prigogine and coworkers is generalized and its dynamical properties are
reexamined. It is shown that the starting point of these models depends
critically on a dimensionless parameter , closely related to the matter
creation rate . For bigger or smaller than unity flat universes
can emerge, respectively, either like a Big-Bang FRW singularity or as a
Minkowski space-time at . The case corresponds to a de
Sitter-type solution, a fixed point in the phase diagram of the system,
supported by the matter creation process. The curvature effects have also been
investigated. The inflating de Sitter is a universal attractor for all
expanding solutions regardless of the initial conditions as well as of the
curvature parameter.Comment: 25 pages, 2 figures(available from the authors), uses LATE
Awaking the vacuum in relativistic stars
Void of any inherent structure in classical physics, the vacuum has revealed
to be incredibly crowded with all sorts of processes in relativistic quantum
physics. Yet, its direct effects are usually so subtle that its structure
remains almost as evasive as in classical physics. Here, in contrast, we report
on the discovery of a novel effect according to which the vacuum is compelled
to play an unexpected central role in an astrophysical context. We show that
the formation of relativistic stars may lead the vacuum energy density of a
quantum field to an exponential growth. The vacuum-driven evolution which would
then follow may lead to unexpected implications for astrophysics, while the
observation of stable neutron-star configurations may teach us much on the
field content of our Universe.Comment: To appear in Phys. Rev. Let
Analysis of the dynamics of a spacecraft in the vicinity of an asteroid binary system with equal masses
In this work, we performed a dynamical analysis of a spacecraft around a
nearly equal-mass binary near-Earth asteroid with application to the asteroid
2017 YE5, which is also a possible dormant Jupiter-family comet. Thus, we
investigated the motion of a particle around this binary system using the
circular restricted three-body problem. We calculated the locations of the
Lagrangian points of the system and their Jacobi constant. Through numerical
simulations, using the Poincar\'e Surface of Sections, it was possible to find
several prograde and retrograde periodic orbits around each binary system's
primary, some exhibiting significantly-sized higher-order behavior. We also
calculated the stability of these orbits. After finding the periodic orbits, we
investigated the influence of solar radiation pressure on these orbits. For
this analysis, we considered that the area-to-mass ratio equals 0.01 and 0.1.
We also performed a spacecraft lifetime analysis considering the physical and
orbital characteristics of the 2017YE5 system and investigated the behavior of
a spacecraft in the vicinity of this system. We analyzed direct and retrograde
orbits for different values of Jacobi's constant. This study investigated
orbits that survive for at least six months, not colliding or escaping the
system during that time. We also analyze the initial conditions that cause the
spacecraft to collide with or , or escape from the system. In this
work, we take into account the gravitational forces of the binary asteroid
system and the solar radiation pressure (SRP). Finally, we calculated optimal
bi-impulsive orbital maneuvers between the collinear Lagrangian points. We
found a family of possible orbital transfers considering times of flight
between 0.1 and 1 day
Soroepidemiologia do lentivirus em ovinos no Semiárido baiano.
[Epidemiology of small ruminant lentiviruses in sheep semiarid of Bahia]. Abstract: To verify the occurrence of antibodies against SRLV in sheep flocks from farms located in Microregion of Feira de Santana, Bahia, we performed a seroepidemiological survey of 10 municipalities with the most effective micro sheep: Antonio Cardoso, Feira de Santana, Ipecaetá , Ipirá, Itatim, Pintadas, Rafael Jambeiro, Santa Terezinha, Santo Estevão e Serra Preta, totaling 384 samples collected from 48 municipalities visited properties. The samples were subjected to the test of agar gel immunodiffusion (AGID) to give negative results in all sera investigated. This finding can be attributed to the composition of herds, which are mostly of animals breed, the system of creation predominantly semi-extensive and type of exploitation for meat, which reduced the risk of introduction of lentivirus . Therefore, in order to preserve the genetic material already adapted to semi-arid climatic adversities, sanitary measures can be taken to prevent the entry of infectious agents circulating in these herds. This is necessary especially because of the tendencies of improving the productivity of small ruminant animals by the introduction of imported breed
- …