2,434 research outputs found
Absorption Enhancing Excipients in Systemic Nasal Drug Delivery
Intranasal drug delivery is becoming an increasingly important form of drug administration for chronic and chronic-intermittent diseases. Important new applications in development include drugs for diabetes, osteoporosis, obesity, certain types of convulsive disorders, migraine headaches, symptomatic pain relief, nausea, and anxiety, among others. Transmucosal absorption across the nasal mucosa is generally limited to molecules under 1,000 Da in size. Systemic delivery of molecules larger than this requires formulation with a suitable transmucosal absorption enhancer. More than one hundred potential transmucosal absorption enhancing excipients have been tested to date. Nearly all have failed to be practical due to poor effectiveness or unacceptable toxicity to mucosal tissue. Alkylsaccharides, cyclodextrins, and chitosan's have emerged as the leading candidates for potential broad clinical applications and are allowing development of convenient, patient-friendly, needle free formulations of small molecule drugs, as well as peptide and protein drugs that can be administered at home, at work, or in other public and private settings outside of the doctor’s office or hospital environment
FUV variability of HD 189733. Is the star accreting material from its hot Jupiter?
Hot Jupiters are subject to strong irradiation from the host stars and, as a
consequence, they do evaporate. They can also interact with the parent stars by
means of tides and magnetic fields. Both phenomena have strong implications for
the evolution of these systems. Here we present time resolved spectroscopy of
HD~189733 observed with the Cosmic Origin Spectrograph (COS) on board to HST.
The star has been observed during five consecutive HST orbits, starting at a
secondary transit of the planet ( ~0.50-0.63). Two main episodes of
variability of ion lines of Si, C, N and O are detected, with an increase of
line fluxes. Si IV lines show the highest degree of variability. The FUV
variability is a signature of enhanced activity in phase with the planet
motion, occurring after the planet egress, as already observed three times in
X-rays. With the support of MHD simulations, we propose the following
interpretation: a stream of gas evaporating from the planet is actively and
almost steadily accreting onto the stellar surface, impacting at
ahead of the sub-planetary point.Comment: 35 pages, 19 Figures. Accepted for publication to Ap
Fingerprint of dynamical charge/spin correlations in the tunneling spectra of colossal magnetoresistive manganites
We present temperature-dependent scanning tunneling spectroscopy measurements
on () films with different degrees of biaxial
strain. A depletion in normalized conductance around the Fermi level is
observed both above and below the insulator-to-metal transition temperature
, for weakly as well as highly-strained films. This pseudogap-like
depletion globally narrows on cooling. The zero-bias conductance decreases on
cooling in the insulating phase, reaches a minimum close to and
increases on cooling in the metallic phase, following the trend of macroscopic
conductivity. These results support a recently proposed scenario in which
dynamical short-range antiferromagnetic/charge order correlations play a
preeminent role in the transport properties of colossal magnetoresistive
manganites [R. Yu \textit{et al}., Phys. Rev. B \textbf{77}, 214434 (2008)].Comment: 9 pages, 4 figure
Scaling laws of solar and stellar flares
In this study we compile for the first time comprehensive data sets of solar
and stellar flare parameters, including flare peak temperatures T_p, flare peak
volume emission measures EM_p, and flare durations t_f from both solar and
stellar data, as well as flare length scales L from solar data. Key results are
that both the solar and stellar data are consistent with a common scaling law
of EM_p ~ T_p^4.7, but the stellar flares exhibit ~250 times higher emission
measures (at the same flare peak temperature). For solar flares we observe also
systematic trends for the flare length scale L(T_p) ~ T_p^0.9 and the flare
duration t_F(T_p) ~ T_p^0.9 as a function of the flare peak temperature. Using
the theoretical RTV scaling law and the fractal volume scaling observed for
solar flares, i.e., V(L) ~ L^2.4, we predict a scaling law of EM_p ~ T_p^4.3,
which is consistent with observations, and a scaling law for electron densities
in flare loops, n_p ~ T_p^2/L ~ T_p^1.1. The RTV-predicted electron densities
were also found to be consistent with densities inferred from total emission
measures, n_p=(EM_p/q_V*V)^1/2, using volume filling factors of q_V=0.03-0.08
constrained by fractal dimensions measured in solar flares. Our results affect
also the determination of radiative and conductive cooling times, thermal
energies, and frequency distributions of solar and stellar flare energies.Comment: 9 Figs., (paper in press, The Astrophsycial Journal
Sambucus nigra L. (fam. Viburnaceae) in Sicily: Distribution, Ecology, Traditional Use and Therapeutic Properties
Sambucus nigra, the elderberry, has long been used for its medicinal properties in treating numerous diseases. Based on this traditional knowledge, its different pharmacological activities have been the focus of active research. All parts of the tree have long been used in traditional medicine, that is, the bark, the leaves, the flowers and the fruit. This study, carried out in Sicily (Italy), concerns the traditional uses of elder against human diseases. In order to trace the history of man's interaction with elder on the island, multidisciplinary research was carried out, aiming at (1) presenting a comprehensive overview of elderberry's applications and activities and (2) bridging traditional knowledge (uses and beliefs) with modern science, i.e., the most recent scientific findings in the biomedical and pharmacological fields. A rigorous literature review of scientific (and other local) reports on the elderberry tree and its application in food, health and household applications was undertaken. This article also provides a synthetic and updated picture of the ecology and distribution of S. nigra in Sicily. The elderberry is quite widespread in Sicily, yet its distribution is discontinuous. It prefers hedges, riparian woodlands, forest margins and clearings and is rather common along the watercourses flowing in the canyons of the Hyblaean Plateau, in the Madonie Mts. and in Enna province. Indeed, many old plants are often found near sacred places and rural houses, suggesting that in the past, it was extensively planted on purpose for its multiple uses. The complementary data obtained from multidisciplinary research confirm the usefulness of this approach in building a comprehensive and correct picture of the distribution of the most common woody species, for which the available knowledge is often fragmentary and imprecise
Polysorbates, peroxides, protein aggregation, and immunogenicity – a growing concern
Aggregation can have a number of deleterious effects on biotherapeutics including the loss of efficacy, the induction of unwanted immunogenicity, altered pharmacokinetics, and reduced shelf life. Aggregation is ameliorated by the inclusion of surfactants in biotherapeutics formulations, typically non-ionic polymeric ether surfactants. The most commonly used examples are Tween® 20 (Polysorbate 20) and Tween® 80 (Polysorbate 80). Others include Triton™ X-100, Pluronic® F-68, Pluronic® F-88, Pluronic® F-127 (poloxamers), and Brij 35 (polyoxyethylene alkyl ether). The usefulness of polysorbates, in particular in preventing protein aggregation in biotherapeutic formulations, is well accepted. However, polysorbates contain ether linkages and unsaturated alkyl chains that have been shown to auto-oxidize in aqueous solution to protein-damaging peroxides and reactive aldehydes including formaldehyde and acetaldehyde. The peroxides principally affect methionine and tryptophan moieties. The aldehydes react with primary amino groups on proteins and are known to induce immunogenicity of proteins in the absence of aggregation or adjuvants. Detection of protein aggregation and prevention of aggregation using polysorbates is relatively
straightforward using light scattering or size exclusion chromatography methods. Detection of oxidative damage to amino acyl moieties or increased immunogenicity resulting from the reaction of biotherapeutics with the degradation products of polysorbates is considerably more difficult and has generally been ignored in the scientific literature. As an increasing number of biotherapeutic agents come into use in common clinical practice, including both as innovator and as biosimilar products, these latter issues will come under increased scrutiny. Substitution of non-ionic, non-ether-based surfactants, could offer significant improvements in stability, reduced immunogenicity, and shelf life, and represents a significant unmet need in the field of biotherapeutics formulation
Vortex Structure in Superconducting Stripe States
The vortex structure in superconducting stripe states is studied according to
the Bogoliubov-de Gennes theory on the two-dimensional Hubbard model with
nearest-neighbor sites pairing interaction. The vortex is trapped at the
outside region of the stripe line, where the superconductivity is weak. The
superconducting coherence length along the stripe direction becomes long. There
are no eminent low-energy electronic states even near the vortex core. These
characters resemble the Josephson vortex in layered superconductors under a
parallel field.Comment: LaTeX 5 pages (using jpsj macros) with 3 figure
Anti-phase Modulation of Electron- and Hole-like States in Vortex Core of Bi2Sr2CaCu2Ox Probed by Scanning Tunneling Spectroscopy
In the vortex core of slightly overdoped Bi2Sr2CaCu2Ox, the electron-like and
hole-like states have been found to exhibit spatial modulations in anti-phase
with each other along the Cu-O bonding direction. Some kind of
one-dimensionality has been observed in the vortex core, and it is more clearly
seen in differential conductance maps at lower biases below +-9 mV
The Stock Genetic Structure of Two Sparidae Species, Diplodus vulgaris and Lithognathus mormyrus, in the Mediterranean Sea.
Polyacrilamide gel electrophoresis (PAGE) of allozymes was used to investigate the intraspecies genetic variation and
the genetic stock structure of Diplodus vulgaris and Lithognathus mormyrus captured from eight localities in the Mediterranean
Sea. Twenty-two and 20 putative enzyme-coding loci were examined, respectively, in D. vulgaris and L. mormyrus.
Polymorphic loci at the 95% level were used to assess the allozyme variability in D. vulgaris (AAT-2, EST-1, GLDH,
PEPB-2, PGI-2, PGM, SDH) and L. mormyrus (AAT-2, EST-1, GLDH, MDH-2, PGI-2, PGM). The proportion
of polymorphic loci in both species ranged from 0.31 (D. vulgaris) to 0.30 (L. mormyrus), and the observed and expected
mean heterozygosity varied between 0.082 and 0.093 (D. vulgaris) and between 0.069 and 0.072 (L. mormyrus). The mean
value of observed heterozygosity in D. vulgaris showed a deficit of heterozygosites, thereby indicating a Wahlund effect
in the samples examined. Significant genetic differentiation (mean value of θ = 0.013, p < 0.005) was found in D.
vulgaris indicating an intraspecific genetic substructure among the samples examined, whereas the mean value of θ = 0.001, p > 0.05 found in L. mormyrus showed a high degree of genetic homogeneity. The results showed the presence
of distinct subpopulations of D. vulgaris among the sampled sites, and suggested that analysis of allozymes may provide
important information on the genetic stock structure of these two sparids to ensure sustainable management of these
species
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