1,154 research outputs found
Medicated foams and film forming dosage forms as tools to improve the thermodynamic activity of drugs to be administered through the skin
Medicated foams and film forming systems are dosage forms formulated to undergo to a controlled metamorphosis when applied on the skin. Indeed, due to the presence of propellant or a particular air-spray foam pump, a liquid can generate a foam when applied on the stratum corneum, or a liquid or conventional dosage form can form on the skin a continuous film as a consequence of the solvent evaporation. Thanks to these controlled modifications, the drug thermodynamic activity increases favoring the skin penetration and, therefore, the bioavailability with respect to conventional semi-solid and liquid dosage forms. Furthermore, the available clinical data also evidence that these dosage forms improve the patient's compliance. The main formulative aspects of medicated foams and film forming systems are reviewed with the aim to underline the possible advantages in terms of biopharmaceutical performances and patient's adherence
The TNG Near Infrared Camera Spectrometer
NICS (acronym for Near Infrared Camera Spectrometer) is the near-infrared
cooled camera-spectrometer that has been developed by the Arcetri Infrared
Group at the Arcetri Astrophysical Observatory, in collaboration with the
CAISMI-CNR for the TNG (the Italian National Telescope Galileo at La Palma,
Canary Islands, Spain).
As NICS is in its scientific commissioning phase, we report its observing
capabilities in the near-infrared bands at the TNG, along with the measured
performance and the limiting magnitudes. We also describe some technical
details of the project, such as cryogenics, mechanics, and the system which
executes data acquisition and control, along with the related software.Comment: 7 pages, 5 figures, compiled with A&A macros. A&A in pres
Acceleration of hemiacetal cleavage through hydrogen bonding : a new synthetic catalyst with balanced conformational flexibility and preorganization
Hemiacetal cleavage catalyst 1 was designed, synthesized, and shown to be effective in promoting glycolaldehyde dimer dissociation and tetramethylglucose mutarotation
Discovery of strong CIV absorption in the highest redshift quasar
We report the near-IR detection of a prominent CIV absorption in the
rest-frame UV spectrum of the most distant known QSO, SDSS J104433.04-012502.2,
at z=5.80. This QSO was recently observed with XMM-Newton and it was found to
be notably X-ray weak. The equivalent width of the CIV absorption feature (~10
A) strongly supports the idea that the X-ray faintness of this QSO is due to
heavy absorption by gas with a column density N_H > 10^{24} cm^-2. The shape of
the CIV feature suggests that this is a Broad Absorption Line QSO. Although
absorbed by a huge column of gas, the observed continuum in the 0.9-2.4um range
(~1300-3500 A rest frame) exactly matches the template of unabsorbed QSOs
without invoking any reddening (E(B-V)<0.08 mag), indicating that dust in the
absorbing gas is either absent or composed of large grains.Comment: 4 pages, 2 figures, accepted for publication in A&A Letter
Solid state hydrogen storage in alanates and alanate-based compounds: A review
The safest way to store hydrogen is in solid form, physically entrapped in molecular form in highly porous materials, or chemically bound in atomic form in hydrides. Among the different families of these compounds, alkaline and alkaline earth metals alumino-hydrides (alanates) have been regarded as promising storing media and have been extensively studied since 1997, when Bogdanovic and Schwickardi reported that Ti-doped sodium alanate could be reversibly dehydrogenated under moderate conditions. In this review, the preparative methods; the crystal structure; the physico-chemical and hydrogen absorption-desorption properties of the alanates of Li, Na, K, Ca, Mg, Y, Eu, and Sr; and of some of the most interesting multi-cation alanates will be summarized and discussed. The most promising alanate-based reactive hydride composite (RHC) systems developed in the last few years will also be described and commented on concerning their hydrogen absorption and desorption performance
Design of pressure-sensitive adhesive suitable for the preparation of transdermal patches by hot-melt printing
This work aimed to design low-melting pressure sensitive adhesives and to demonstrate the feasibility of the preparation of (trans)dermal patches by hot-melt ram extrusion printing. This approach allows defining both the geometry of (trans)dermal patch and the drug strength easily according to patient needs. The preparation steps are the mixing of a poly-ammonium methacrylate polymer (i.e. Eudragit RL and RS) with a suitable amount of plasticizer (triacetin or tributyl citrate) and drug (ketoprofen or nicotine), the melting in the ram extruder, and the printing on the backing layer foil. The formulations were characterized in terms of rheological and adhesive properties, in vitro drug release and skin permeation profiles.
The (trans)dermal patches made of Eudragit RL or Eudragit RS plasticized with the 40% triacetin could be printed at 90 \ub0C giving formulations with suitable adhesive properties and without cold flow after 1 month of storage at 40 \ub0C. Furthermore, the overall results showed that the performances of printed (trans)dermal patches overlapped those made by solvent casting, suggesting that the proposed solvent-free technology can be useful to treat cutaneous pathologies when the availability of (trans)dermal patches with size and shape that perfectly fit with the skin area affected by the disease improves the safety of the pharmacological treatment
The past to unravel the future: Deoxygenation events in the geological archive and the anthropocene oxygen crisis
Despite the observation that we are witnessing a true oxygen crisis, the ocean deoxygenation theme is getting less attention from the media and population compared to other environmental stressors concerning climate change. The current ocean oxygen crisis is characterized by a complex interplay of climatic, biological, and oceanographic processes acting at different time scales. Earth system models offer insights into future deoxygenation events and their potential extent; however, their capacity to precisely constrain these events is complicated by the intricate interplay of various interconnected feedback mechanisms. The Earth's geological history has been punctuated by regional and global deoxygenation events, which are usually expressed by organic-rich sediment in the geological record and can be useful past analogues of the present-day and future oxygenation crisis related to current climatic stress.
Accordingly, we provide an overview of the key elements characterizing past deoxygenation events, aiming for a better understanding of the Anthropocene oxygen crisis and its potential evolution. We suggest that past global deoxygenation events during hypethermals may bear similarities to present-day dynamics in the open ocean. Additionally, we explore the significance of regional deoxygenation events with cyclical occurrences for better constraining environmental dynamics and ecological impacts in semi-enclosed, restricted, and marginal basins. Despite the unprecedented magnitude and rate of current anthropogenic pressures, it is essential to consider the comparison of triggers and feedbacks from ancient deoxygenation events when investigating the future of this concealed but ecologically impactful problem
Exploring Brown Dwarf Disks in rho Oph
This paper discusses evidence for and properties of disks associated to brown
dwarfs in the star-forming region rho-Oph. We selected nine objects fr om the
ISOCAM survey of Bontemps et al. (2001) that have detections in the two
mid-infrared bands (6.7 and 14.3 um), relatively low extinction and low
luminosity. We present low-resolution near-infrared spectra in the J, H and K
bands, and determine for each source spectral type, extinction, effective
temperature a nd luminosity by comparing the spectra to those of field dwarfs
and to the most recent model stellar atmospheres. The results indicate that
eight objects have spectral types M6-M7.5, effective temperature of 2600-2700
K, one has a later spectral type (M8.5) and lower temperature (about 2400 K).
The derived extinctions range between Av~2 and 8 mag. The location of the
objects on the HR diagram, in spite of the uncertainties of the evolutionary
tracks for young objects of substellar mass, indicates that all the objects are
very young and have masses below about 0.08 Msun. The coolest object in our
sample has mass in the range 8-12 Mjup (0.008-0.012 Msun). In all cases, the
mid-infrared excess is consistent with the predictions of mode ls of disks
irradiated by the central object, showing that circumstellar disks are commonly
associated to young brown dwarfs and plan etary-mass objects. Finally, we
discuss possible variations of the disk geometry among different objects, as
well as the possibility of using these data to discriminate between various f
ormation scenarios.Comment: 15 pages, A&A in press, full resolution color figures for appendix A
and B are available at
http://www.arcetri.astro.it/~lt/preprints/preprints.htm
Recent progress and new perspectives on metal amide and imide systems for solid-state hydrogen storage
Hydrogen storage in the solid state represents one of the most attractive and challenging ways to supply hydrogen to a proton exchange membrane (PEM) fuel cell. Although in the last 15 years a large variety of material systems have been identified as possible candidates for storing hydrogen, further efforts have to be made in the development of systems which meet the strict targets of the Fuel Cells and Hydrogen Joint Undertaking (FCH JU) and U.S. Department of Energy (DOE). Recent projections indicate that a system possessing: (i) an ideal enthalpy in the range of 20-50 kJ/mol H2, to use the heat produced by PEM fuel cell for providing the energy necessary for desorption; (ii) a gravimetric hydrogen density of 5 wt. % H2 and (iii) fast sorption kinetics below 110 °C is strongly recommended. Among the known hydrogen storage materials, amide and imide-based mixtures represent the most promising class of compounds for on-board applications; however, some barriers still have to be overcome before considering this class of material mature for real applications. In this review, the most relevant progresses made in the recent years as well as the kinetic and thermodynamic properties, experimentally measured for the most promising systems, are reported and properly discussed
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