22 research outputs found
Comparison of magnetic and non-magnetic nanoparticles as sonosensitizers in ultrasonic hyperthermia
Nanoparticles have attracted a great interest in scientific world because of the new applications they offer. They are commonly used in medical procedures such as hyperthermia and thermal ablation. Here, we propose, using magnetic and non-magnetic nanoparticles, as sonosensitizers which are the materials that improve the efficiency of heating induced by ultrasound. A comparison between various types of nanomaterials, such as magnetite, silicon dioxide, and Laponite nanoparticles, was done. The results show that both magnetic and non-magnetic nanomaterials can be utilized in ultrasonic heating. However, magnetite nanoparticles without surface modification can strongly interact with each other and are prone to agglomeration that can deteriorate thermal effect in tissuemimicking phantoms
The interstellar medium towards the Ara OB1 region
We present high resolution (R ~ 4 km/s) absorption measurements of the
interstellar NaI and CaII lines measured towards 14 early-type stars of
distance 123 pc - 1650 pc, located in the direction of the Ara OB1 stellar
cluster. The line profiles can broadly be split into four distinct groupings of
absorption component velocity, and we have attempted to identify an origin and
distance to each of these interstellar features. For gas with absorption
covering the velocity range -10 km/s < V_helio < +10 km/s, we can identify the
absorbing medium with local gas belonging to the Lupus-Norma interstellar
cavity located between 100 and 485 pc in this galactic direction. Gas with
velocities spanning the range -20 km/s < V_helio < +20 km/s is detected towards
stars with distances of 570-800 pc. We identify a wide-spread interstellar
feature at V_helio ~ -15 km/s with the expanding HI shell called GSH 337+00-05,
which is now placed at a distance of ~530 pc.Comment: 12 pages, 5 figures, accepted for publication in Astrophysics & Space
Scienc
Multi-epoch high-resolution spectroscopy of SN2011fe - Linking the progenitor to its environment
This study attempts to establish a link between the reasonably well known
nature of the progenitor of SN2011fe and its surrounding environment. This is
done with the aim of enabling the identification of similar systems in the vast
majority of the cases, when distance and epoch of discovery do not allow a
direct approach. To study the circumstellar environment of SN2011fe we have
obtained high-resolution spectroscopy of SN2011fe on 12 epochs, from 8 to 86
days after the estimated date of explosion, targeting in particular at the time
evolution of CaII and NaI. Three main absorption systems are identified from
CaII and NaI, one associated to the Milky Way, one probably arising within a
high-velocity cloud, and one most likely associated to the halo of M101. The
Galactic and host galaxy reddening, deduced from the integrated equivalent
widths (EW) of the NaI lines are E(B-V)=0.011+/-0.002 and E(B-V)=0.014+/-0.002
mag, respectively. The host galaxy absorption is dominated by a component
detected at the same velocity measured from the 21-cm HI line at the projected
SN position (~180 km/s). During the ~3 months covered by our observations, its
EW changed by 15.6+/-6.5 mA. This small variation is shown to be compatible
with the geometric effects produced by therapid SN photosphere expansion
coupled to the patchy fractal structure of the ISM. The observed behavior is
fully consistent with ISM properties similar to those derived for our own
Galaxy, with evidences for structures on scales <100 AU. SN2011fe appears to be
surrounded by a "clean" environment. The lack of blue-shifted, time-variant
absorption features is fully consistent with the progenitor being a binary
system with a main-sequence, or even another degenerate star.Comment: 12 pages, 6 figures, submitted to Astronomy and Astrophysic
High-resolution observations of interstellar Na I and Ca II towards the southern opening of the 'Local Interstellar Chimney': probing the disc—halo connection
We present high-resolution (R = 400 000) observations of interstellar Ca II and Na I absorption lines towards seven stars in the direction of the southern opening of the recently identified Local Interstellar Chimney. These lines of sight probe the lower Galactic halo (0.3 ≲∣z∣≲ 2.5 kpc), without the complication of sampling dense foreground interstellar material. In addition to components with velocities expected from Galactic rotation, these stars also exhibit components with negative local standard of rest velocities, which are contrary to the sense of Galactic rotation for the sightlines observed. After a discussion of possible origins for these peculiar velocities, we conclude that at least some of them result from gas falling towards the Galactic plane from distances of ∣z∣≳ 300 pc. The narrow linewidths are generally inconsistent with temperatures as high as the ∼6000 K generally assumed for the so-called Lockman layer. Rather, the picture that emerges is one of a scattered, generally infalling, population of high-∣z∣ diffuse clouds, seemingly not very different from those encountered in the local interstellar medium. Overall, we argue that our results are most consistent with a ‘Galactic fountain’ model
Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU
Contains fulltext :
172380.pdf (publisher's version ) (Open Access
Riboflavin Binding Protein Chiral Stationary Phase: Investigation on the Retention Mechanism.
The chiral recognition mechanism of Riboflavin Binding Protein (RfBP) stationary phase has been investigated by studying the influence of temperature on the retention process.
The effect of temperature on retention and resolution of two analytes was studied between 15°C and 55°C and van't Hoff plots of lnk and ln versus 1/T were acquired. The thermodynamic parameters were calculated and the data were used to derive some information regarding the retention mechanism in this chromatographic system.
Quantitative structure-enantioselective retention relationships (QSERR) were derived by multiple regression analysis using various molecular descriptors and the retention data determined on RfBP-stationary phase. The results were interpreted in terms of structural requirements of the specific binding site on the biomacromolecule to provide an insight of the recognition mechanism
New chemical structures of hypolipidemic and antiplatelet activity*
Abstract: Elevated lipid level is supposed to be one of the main risk factors of atherosclerosis and subsequent cardiovascular disease (and is connected to mortality). Therefore, lipid lowering is one of the major targets in cardiovascular disease treatment and prevention. Also, blood platelets play a pivotal role in the development of atherosclerosis and fatal thrombus formation in the course of coronary heart disease. Therefore, there is a great necessity to acquire drugs inhibiting platelet aggregation and clot generation. The present paper reviews new chemical structures in development for the treatment and prevention of hyperlipidemia, atherosclerosis, and subsequent cardiovascular disease. The authors' recent results are also reported regarding synthesis of a new group of α-asarone analogs. These compounds were identified as an original class of agents exhibiting hypolipidemic and antiplatelet (mice, rats) activities. Although the mechanism of the compounds' pharmacological activity has not been identified, quantum-mechanical calculations allowed structural requirements to be described that correspond to the activity (a hypothetical pseudoreceptor structure). Since it is known that asarone and its derivatives may exhibit genotoxicity, calculations were carried out to identify derivatives of possibly low genotoxic activity