1,324 research outputs found
Medicinal Chemistry approach, pharmacology and neuroprotective benefits of CB2R modulators in neurodegenerative diseases
In the last decades, cannabinoid receptor 2 (CB2R) has continued to receive attention as a key therapeutic target in neuroprotection. Indeed, several findings highlight the neuroprotective effects of CB2R through suppression of both neuronal excitability and reactive microglia. Additionally, CB2R seems to be a more promising target than cannabinoid receptor 1 (CB1R) thanks to the lack of central side effects, its lower expression levels in the central nervous system (CNS), and its inducibility, since its expression enhances quickly in the brain following pathological conditions. This review aims to provide a thorough overview of the main natural and synthetic selective CB2R modulators, their chemical classification and their potential therapeutic usefulness in neuroprotection, a crucial aspect for the treatment of neurodegenerative diseases
Desempenho produtivo de ovinos mantidos em pastagens de capim Tifton 85 recebendo doses crescentes de concentrado.
O estudo foi conduzido com o objetivo de avaliar o desempenho produtivo de ovinos mantidos em pastagens irrigadas de Tifton 85 recebendo doses crescentes de suplemento concentrado. Foram utilizados 24 ovinos, machos, castrados, com peso médio inicial de 20 kg como animais testadores. As doses de concentrado avaliadas foram 0; 0,66; 1,33 e 2,0% de matéria seca de suplemento em relação ao peso corporal dos animais. O delineamento experimental foi o inteiramente casualizado com seis repetições por tratamento. Foram observados maiores (P<0,05) ganhos médios diários e ganhos de pesos totais para os animais que receberam 2% de concentrado. Os animais que não receberam suplementação apresentaram os menores (P<0,05) ganhos médios diários e ganhos de pesos totais. O aumento nas doses de concentrado para ovinos mantidos em pastagens de Tifton 85 melhorou o desempenho produtivo dos animais
Desempenho produtivo de ovinos mantidos em pastagens irrigadas suplementados com concentrado contendo diferentes resíduos do processamento de frutas.
Large scale structure and the generalised Chaplygin gas as dark energy
The growth of large scale structure is studied in a universe containing both
cold dark matter (CDM) and generalized Chaplygin gas (GCg). GCg is assumed to
contribute only to the background evolution of the universe while the CDM
component collapses and forms structures. We present some new analytical as
well as numerical results for linear and non-linear growth in such model. The
model passes the standard cosmological distance test without the need of a
cosmological constant (LCDM). But we find that the scenario is severely
constrained by current observations of large scale structure. Any small
deviations of the GCg parameters away from the standard Lambda dominated
cosmology (LCDM) produces substantial suppression for the growth of structures.Comment: 6 pages, matches version accepted for publication in Phys.Rev.D (in
press
PSNCBAM-1 analogs: Structural evolutions and allosteric properties at cannabinoid CB1 receptor
Allosteric modulation of the CB1Rs could represent an alternative strategy for the treatment of diseases in which these receptors are involved, without the undesirable effects associated with their orthosteric stimulation. PSNCBAM-1 is a reference diaryl urea derivative that positively affects the binding affinity of orthosteric ligands (PAM) and negatively affects the functional activity of orthosteric ligands (NAM) at CB1Rs. In this work we reported the design, synthesis and biological evaluation of three different series of compounds, derived from structural modifications of PSNCBAM-1 and its analogs reported in the recent literature. Almost all the new compounds increased the percentage of binding affinity of CP55940 at CB1Rs, showing a PAM profile. When tested alone in the [35S]GTPγS functional assay, only a few derivatives lacked detectable activity, so were tested in the same functional assay in the presence of CP55940. Among these, compounds 11 and 18 proved to be functional NAMs at CB1Rs, dampening the orthosteric agonist-induced receptor functionality by approximately 30%. The structural features presented in this work provide new CB1R-allosteric modulators (with a profile similar to the reference compound PSNCBAM-1) and an extension of the structure-activity relationships for this type of molecule at CB1Rs
Composição química da carne de cabritos Saanen arraçoados com diferentes proporções de concentrado e volumoso.
O objetivo do presente estudo foi avaliar a composição química da carne de cabritos da raça Saanen submetidos a quatro relações de concentrado e volumoso (C:V) (80:20; 60:40; 40:60 e 20:80% de C:V) na matéria seca de rações, tendo o capim Elefante in natura picado como volumoso base. Foram utilizados 28 caprinos, machos, distribuídos em quatro grupos, em baias coletivas, sendo que, cada baia continha sete animais. O delineamento experimental adotado foi o inteiramente casualizado com sete repetições por tratamento. As variáveis analisadas foram os teores de matéria seca, proteína bruta, extrato etéreo e cinzas. Foram observados maiores teores de matéria seca (P0,05) pelas doses de concentrado. Assim, o incremento na proporção de concentrado nas rações elevou os teores de matéria seca da carne caprina
Static Configurations of Dark Energy and Dark Matter
We study static configurations of dark matter coupled to a scalar field
responsible for the dark energy of the Universe. The dark matter is modelled as
a Fermi gas within the Thomas-Fermi approximation. The mass of the dark matter
particles is a function of the scalar field. We analyze the profile of the dark
matter halos in galaxies. In this case our framework is equivalent to the model
of the isothermal sphere. In the presence of a scalar field, the velocity of a
massive object orbiting the galaxy is not of the order of the typical velocity
of the dark matter particles, as in the conventional picture. Instead, it is
reduced by a factor that quantifies the dependence of the dark matter mass on
the scalar field. This has implications for dark matter searches. We derive new
solutions of the Einstein equations which describe compact objects composed of
dark matter. Depending on the scale of the dark matter mass, the size of these
objects can vary between microscopic scales and cosmological distances. We
determine the mass to radius relation and discuss the similarities with
conventional neutron stars and exotic astrophysical objects.Comment: 23 pages, 3 figures, minor additions to the tex
Cosmological Models and Latest Observational Data
In this note, we consider the observational constraints on some cosmological
models by using the 307 Union type Ia supernovae (SNIa), the 32 calibrated
Gamma-Ray Bursts (GRBs) at , the updated shift parameter from WMAP
5-year data (WMAP5), and the distance parameter of the measurement of the
baryon acoustic oscillation (BAO) peak in the distribution of SDSS luminous red
galaxies with the updated scalar spectral index from WMAP5. The tighter
constraints obtained here update the ones obtained previously in the
literature.Comment: 10 pages, 5 figures, 1 table, revtex4; v2: discussions added,
accepted by Eur. Phys. J. C; v3: published versio
20-ps resolution Clock Distribution Network for a fast-timing single photon detector
The time resolution of active pixel sensors whose timestamp mechanism is based on Time-to-Digital Converters is critically linked to the accuracy in the distribution of the master clock signal that latches the timestamp values across the detector. The Clock Distribution Network that delivers the master clock signal must compensate process-voltage-temperature variations to reduce static time errors (skew), and minimize the power supply bounce to prevent dynamic time errors (jitter). To achieve sub-100ps time resolution within pixel detectors and thus enable a step forward in multiple imaging applications, the network latencies must be adjusted in steps well below that value. Power consumption must be kept as low as possible. In this work, a self-regulated Clock Distribution Network that fulfills these requirements is presented for the FastICpix single photon detector ¿ aiming at a 65nm process. A 40 MHz master clock is distributed to 64x64 pixels over an area of 2.4x2.4 cm2 using digital Delay-Locked Loops, achieving clock leaf skew below 20 ps with a power consumption of 26 mW. Guidelines are provided to adapt the system to arbitrary chip area and pixel pitch values, yielding a versatile design with very fine time resolution
One simulation to fit them all - changing the background parameters of a cosmological N-body simulation
We demonstrate that the output of a cosmological N-body simulation can, to
remarkable accuracy, be scaled to represent the growth of large-scale structure
in a cosmology with parameters similar to but different from those originally
assumed. Our algorithm involves three steps: a reassignment of length, mass and
velocity units, a relabelling of the time axis, and a rescaling of the
amplitudes of individual large-scale fluctuation modes. We test it using two
matched pairs of simulations. Within each pair, one simulation assumes
parameters consistent with analyses of the first-year WMAP data. The other has
lower matter and baryon densities and a 15% lower fluctuation amplitude,
consistent with analyses of the three-year WMAP data. The pairs differ by a
factor of a thousand in mass resolution, enabling performance tests on both
linear and nonlinear scales. Our scaling reproduces the mass power spectra of
the target cosmology to better than 0.5% on large scales (k < 0.1 h/Mpc) both
in real and in redshift space. In particular, the BAO features of the original
cosmology are removed and are correctly replaced by those of the target
cosmology. Errors are still below 3% for k < 1 h/Mpc. Power spectra of the dark
halo distribution are even more precisely reproduced, with errors below 1% on
all scales tested. A halo-by-halo comparison shows that centre-of-mass
positions and velocities are reproduced to better than 90 kpc/h and 5%,
respectively. Halo masses, concentrations and spins are also reproduced at
about the 10% level, although with small biases. Halo assembly histories are
accurately reproduced, leading to central galaxy magnitudes with errors of
about 0.25 magnitudes and a bias of about 0.13 magnitudes for a representative
semi-analytic model.Comment: 14 pages, 12 figures. Submitted to MNRA
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