125 research outputs found
Near-IR 2D-Spectroscopy of the 4''x 4'' region around the Active Galactic Nucleus of NGC1068 with ISAAC/VLT
We present new near-IR long slit spectroscopic data obtained with ISAAC on
VLT/ANTU (ESO/Paranal) of the central 4''x 4'' region surrounding the central
engine of NGC1068 . Bracket Gamma (Bg) and H2 emission line maps and line
profile grids are produced, at a spatial resolution~0.5" and spectral
resolution 35km/s. Two conspicuous knots of H2 emission are detected at about
1'' on each side of the central engine along PA=90deg, with a projected
velocity difference of 140km/s: this velocity jump has been interpreted in
Alloin et al (2001) as the signature of a rotating disk of molecular material.
Another knot with both H2 and Bg emission is detected to the North of the
central engine, close to the radio source C where the small scale radio jet is
redirected and close to the brightest [OIII] cloud NLR-B. At the achieved
spectral resolution, the H2 emission line profiles appear highly asymmetric
with their low velocity wing being systematically more extended than their high
velocity wing. A simple way to account for the changes of the H2 line profiles
(peak-shift with respect to the systemic velocity, width, asymmetry) over the
entire 4''x 4'' region, is to consider that a radial outflow is superimposed
over the emission of the rotating molecular disk. We present a model of such a
kinematical configuration and compare our predicted H2 emission profiles to the
observed ones.Comment: 15 pages, 11 figures, accepted for publication in A&
The Atp-dependent Rna Helicase Hrpb Plays An Important Role In Motility And Biofilm Formation In Xanthomonas Citri Subsp Citri
Coordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)RNA helicases are enzymes that catalyze the separation of double-stranded RNA (dsRNA) using the free energy of ATP binding and hydrolysis. DEAD/DEAH families participate in many different aspects of RNA metabolism, including RNA synthesis, RNA folding, RNA-RNA interactions, RNA localization and RNA degradation. Several important bacterial DEAD/DEAH-box RNA helicases have been extensively studied. In this study, we characterize the ATP-dependent RNA helicase encoded by the hrpB (XAC0293) gene using deletion and genetic complementation assays. We provide insights into the function of the hrpB gene in Xanthomonas citri subsp. citri by investigating the roles of hrpB in biofilm formation on abiotic surfaces and host leaves, cell motility, host virulence of the citrus canker bacterium and growth in planta. Results: The hrpB gene is highly conserved in the sequenced strains of Xanthomonas. Mutation of the hrpB gene (Delta hrpB) resulted in a significant reduction in biofilms on abiotic surfaces and host leaves. Delta hrpB also exhibited increased cell dispersion on solid medium plates. Delta hrpB showed reduced adhesion on biotic and abiotic surfaces and delayed development in disease symptoms when sprayed on susceptible citrus leaves. Quantitative reverse transcription-PCR assays indicated that deletion of hrpB reduced the expression of four type IV pili genes. The transcriptional start site of fimA (XAC3241) was determined using rapid amplification of 5'-cDNA Ends (5' RACE). Based on the results of fimA mRNA structure predictions, the fimA 5' UTR may contain three different loops. HrpB may be involved in alterations to the structure of fimA mRNA that promote the stability of fimA RNA. Conclusions: Our data show that hrpB is involved in adherence of Xanthomonas citri subsp. citri to different surfaces. In addition, to the best of our knowledge, this is the first time that a DEAH RNA helicase has been implicated in the regulation of type IV pili in Xanthomonas.1635INCT CitrusCAPES/PSDE fellowship [99999.002657/2014-07]CNPqCoordenação de Aperfeiçoamento de Pessoal de NÃvel Superior (CAPES)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq
Restoration of Adiponectin Pulsatility in Severely Obese Subjects After Weight Loss
Diurnal variations of adiponectin levels have been studied in normal-weight men and in diabetic and nondiabetic obese subjects, but no data have been reported in obese subjects after weight loss. We collected blood samples at 1-h intervals over 24 h from seven severely obese subjects before and after massive weight loss consequent to surgical operation (bilio-pancreatic diversion [BPD]) to measure adiponectin, insulin, glucose, and cortisol levels. Insulin sensitivity was assessed by euglycemic-hyperinsulinemic clamp (M value). Studies of diurnal variations and pulsatility of adiponectin, insulin, and cortisol were performed. The pulsatility index (PI) of adiponectin increased after BPD from 0.04 to 0.11 μg/min (P = 0.01). Insulin PI significantly increased after the operation (1.50 vs. 1.08 pmol · l–1 · min–1, P = 0.01), while cortisol PI did not significantly change. The adiponectin clearance rate changed from 0.001 ± 10−4 · min−1 before BPD to 0.004 ± 8 · 10−4 · min−1 after BPD (P = 0.03). Insulin clearance increased from 0.006 ± 6 · 10−4 · min−1 before BPD to 0.009 ± 4 · 10−4 · min−1 after BPD (P = 0.02). The M value doubled after surgery (27.08 ± 8.5 vs. 53.34 ± 9.3 μmol · kgFFM−1 · min−1; P < 0.001) becoming similar to the values currently reported for normal-weight subjects. In conclusion, in formerly severely obese subjects, weight loss paired with the reversibility of insulin resistance restores homeostatic control of the adiponectin secretion, contributing to the reduction of cardiovascular risk already described in these patients
The Dusty Nuclear Torus in NGC 4151: Constraints from Gemini Near-Infrared Integral Field Spectrograph Observations
We have used a near-infrared nuclear spectrum (covering the Z, J, H and K
bands) of the nucleus of NGC 4151 obtained with the Gemini Near-infrared
Integral Field Spectrograph (NIFS) and adaptive optics, to isolate and
constrain the properties of a near-IR unresolved nuclear source whose spectral
signature is clearly present in our data. The near-IR spectrum was combined
with an optical spectrum obtained with the Space Telescope Imaging Spectrograph
which was used to constrain the contribution of a power-law component. After
subtraction of the power-law component, the near-IR continuum is well fitted by
a blackbody function, with K, which dominates the nuclear
spectrum -- within an aperture of radius 0\farcs3 -- in the near-IR. We
attribute the blackbody component to emission by a dusty structure, with hot
dust mass , not resolved
by our observations, which provide only an upper limit for its distance from
the nucleus of 4 pc. If the reddening derived for the narrow-line region also
applies to the near-IR source, we obtain a temperature K and a
mass for the hot dust.
This structure may be the inner wall of the dusty torus postulated by the
Unified Model or the inner part of a dusty wind originating in the accretion
disk.Comment: 5 pages, 1 figure; ApJ, 698, 176
Assessment of solubility and intestinal absorption in vitro of praziquantel in solid dispersions of polyethylene glycol 6000
The aim of this study was to investigate the impact of solid dispersions of polyethylene glycol 6000 (PEG 6000), using the co-precipitation method, on the in vitro solubility and intestinal absorption of praziquantel (PZQ). The solubility of PZQ in solid dispersions and physical mixtures was assessed in purified water and TC-199 buffer. The everted intestinal sac model was employed to assess, in vitro, intestinal absorption of PZQ. A significant enhancement in both in vitro solubility and intestinal absorption of PZQ was found in solid dispersions compared to pure PZQ and physical mixtures. This positive series of preliminary results showed that solid dispersion of PEG 6000 is a valuable strategy for increasing bioavailability of PZQ and could also prove useful for other poorly water-soluble drugs.Colegio de Farmacéuticos de la Provincia de Buenos Aire
SIDA-Sport, Identità ed Adolescenza: Verso la costruzione di un nuovo protocollo di valutazione.
La psicologia dello sport ha abbracciato lo studio dell'identità atletica negli anni Novanta. L’obiettivo della nostra ricerca, dopo un’attenta revisione [Filippini et al,2023]1, è quello di creare un nuovo protocollo, che possa integrare una parte quantitativa ad una parte qualitativa, dando vita, così, ad una nuova batteria di test che vada ad individuare l’efficacia dello sport nella costruzione dell’identità nella fase adolescenzial
A novel gastroretentive floating system for zidovudine, based on calcium-silicate beads
The aim of the research effort entertained herein was to develop, evaluate and fully characterize a multiparticulate floating gastroretentive system for the modified release of zidovudine (AZT), an antiretroviral drug. AZT was used as a water-soluble model drug at therapeutic doses. The floating gastroretentive system was obtained via polymer coating of calcium silicate-adsorbed AZT. The proposed system was evaluated in vitro for particle micromorphology, lag time for floating and duration of floating, drug loading capacity, drug release profile, and drug release kinetics. The physicochemical properties of AZT were evaluated by scanning electron microscopy (SEM) analyses, differential scanning calorimetry (DSC) analyses, X-ray diffraction (XRD) analyses, and infrared spectroscopy (FTIR) analyses. Results from SEM analysis of the AZT-containing floating gastroretentive granules allowed observation of an irregular surface and the apparent absence of pores. Floating of the AZT-containing gastroretentive granules was immediately achieved, that is lag time for floating was virtually zero and duration of floating was higher than 12 h. The drug loading capacity of the floating gastroretentive granules was ca. 81.09 ± 14.66%, and the release system thus obtained exhibited an extended drug release profile. Results from DSC and XRD analyses showed a modification in the AZT solid state, while the FTIR spectroscopy analyses revealed that the chemical structure of AZT remained unchanged upon adsorption to calcium silicate followed by polymeric coating. Hence, the coated granules produced presented gastroretentive, floating, and extended drug release properties.Research Scientist fellowship (
FAPESP Ref. No.
2011/51077
-
8
) is hereby gratefully acknowledged. The
authors also wish to thank Nortec QuÃmica (Rio de
Janeiro RJ, Brazil) for providing the reference materials,
and Almapal (São
Paulo SP, Brazil) and Cristalia
Laboratories (Itapira SP, Brazil) for providing the
samples.
SAU
-
FAR:
The Portuguese Science and
Technology Foundation
(
PTDC/SAU
-
FAR/113100/2009
Probing the near infrared stellar population of Seyfert galaxies
We employ IRTF SpeX NIR (0.8-2.4 microns) spectra to investigate the stellar
population (SP), active galactic nuclei (AGN) featureless continuum (FC) and
hot dust properties in 9 Sy 1 and 15 Sy 2 galaxies. Both the starlight code and
the hot dust as an additional base element were used for the first time in this
spectral range. We found evidence of correlation among the equivalent widths
(W) Si I 1.59 microns x Mg I 1.58 microns, equally for both kinds of activity.
Part of the W{Na I 2.21 microns} and W {CO 2.3 microns} strengths may be
related to galaxy inclination. Our synthesis shows significant differences
between Sy 1 and Sy 2 galaxies: the hot dust component is required to fit the
K-band spectra of ~90% of the Sy 1 galaxies, and only of ~25% of the Sy 2;
about 50 % of the Sy 2 galaxies require a component contribution >20%,
while this fraction increases to 60% in the Sy 1; also, in about 50 % of the
Sy2, the combined FC and young components contribute with more than 20%, while
this occurs in 90% of the Sy1, suggesting recent star formation in the central
region. The central few hundred parsecs of our galaxy sample contain a
substantial fraction of intermediate-age SPs with a mean metallicity near
solar. Our SP synthesis confirms that the 1.1 micron CN band can be used as a
tracer of intermediate-age SPs. The simultaneous fitting of SP, FC and hot dust
components increased in ~150% the number of AGNs with hot dust detected and the
mass estimated. The NIR emerges as an excellent window to study the stellar
population of Sy 1 galaxies, as opposed to the usually heavily attenuated
optical range. Our approach opens a new way to investigate and quantify the
individual contribution of the three most important NIR continuum components
observed in AGNs.Comment: The paper contains 14 figures and 5 tables. Accepted for publication
in MNRA
Mid-Infrared Imaging of Active Galaxies: Active Nuclei and Embedded Star Clusters
High resolution, mid-infrared (MIR) images of a set of nine nearby active
galaxies are presented. The data were obtained with the TIMMI2 instrument
mounted at the ESO 3.6m telescope using a set of N-band narrow filters. The
resulting images have an angular resolution of 0.6"-1". The MIR emission has
been resolved in four galaxies: NGC253, NGC1365, NGC1808 and NGC7469. The
images unveil a circumnuclear population of unknown MIR sources in NGC1365 and
NGC1808, coincident with radio sources. These MIR/radio sources are interpreted
in terms of embedded young star clusters. A high-resolution MIR map of NGC253
is also presented, and enables the identification of a previously unknown MIR
counterpart to the radio nucleus. Extended MIR emission is detected in NGC7469,
and concurs with previous observations in the NIR and radio. For this source,
an interesting morphological difference between the 10.4mic and the 11.9mic
emission is observed, suggesting the presence of a dust-rich micro-bar. Our MIR
images of Circinus do not show resolved emission from the nucleus down to an
angular scale of 0.5". In the case of NGC2992, an upper limit to the extended
MIR emission can be set. Finally, we provide new MIR flux measurements for the
unresolved AGN in NGC5995, IZw1 and IIZw136.Comment: 19 pages, 11 figures, accepted for publication in A&
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