330 research outputs found
Spatiotemporal Amplitude and Phase Retrieval of Bessel-X pulses using a Hartmann-Shack Sensor
We propose a new experimental technique, which allows for a complete
characterization of ultrashort optical pulses both in space and in time.
Combining the well-known Frequency-Resolved-Optical-Gating technique for the
retrieval of the temporal profile of the pulse with a measurement of the
near-field made with an Hartmann-Shack sensor, we are able to retrieve the
spatiotemporal amplitude and phase profile of a Bessel-X pulse. By following
the pulse evolution along the propagation direction we highlight the
superluminal propagation of the pulse peak
Performances of a Newly High Sensitive Trilayer F/Cu/F GMI Sensor
We have selected stress-annealed nanocrystalline Fe-based ribbons for
ferromagnetic/copper/ferromagnetic sensors exhibiting high magneto-impedance
ratio. Longitudinal magneto-impedance reaches 400% at 60 kHz and longitudinal
magneto-resistance increases up to 1300% around 200 kHz.Comment: 4 pages, 6 figures, Sensors and Actuators A (in review
Superluminal Localized Solutions To Maxwell Equations Propagating Along A Normal-sized Waveguide.
We show that localized (nonevanescent) solutions to Maxwell equations exist, which propagate without distortion along normal waveguides with superluminal speed.6406660
Correlation between Group B Streptococcal Genotypes, Their Antimicrobial Resistance Profiles, and Virulence Genes among Pregnant Women in Lebanon
The antimicrobial
susceptibility profiles of 76
Streptococcus agalactiae (Group
B Streptococci [GBS]) isolates from vaginal
specimens of pregnant women near term were
correlated to their genotypes generated by
Random Amplified Polymorphic DNA analysis and
their virulence factors encoding genes
cylE, lmb, scpB, rib, and bca
by PCR. Based on the distribution of the
susceptibility patterns, six profiles were
generated. RAPD analysis detected 7 clusters of
genotypes. The cylE gene was
present in 99% of the isolates, the
lmb in 96%,
scpB in 94.7%,
rib in 33%, and
bca in 56.5% of isolates.
The isolates demonstrated a significant
correlation between antimicrobial resistance and
genotype clusters denoting the distribution of
particular clones with different antimicrobial
resistance profiles, entailing the practice of
caution in therapeutic options. All virulence
factors encoding genes were detected in all
seven genotypic clusters with
rib and bca
not coexisting in the same
genome
On the generalization of the hazard rate twisting-based simulation approach
Estimating the probability that a sum of random variables (RVs) exceeds a given threshold is a well-known challenging problem. A naive Monte Carlo simulation is the standard technique for the estimation of this type of probability. However, this approach is computationally expensive, especially when dealing with rare events. An alternative approach is represented by the use of variance reduction techniques, known for their efficiency in requiring less computations for achieving the same accuracy requirement. Most of these methods have thus far been proposed to deal with specific settings under which the RVs belong to particular classes of distributions. In this paper, we propose a generalization of the well-known hazard rate twisting Importance Sampling-based approach that presents the advantage of being logarithmic efficient for arbitrary sums of RVs. The wide scope of applicability of the proposed method is mainly due to our particular way of selecting the twisting parameter. It is worth observing that this interesting feature is rarely satisfied by variance reduction algorithms whose performances were only proven under some restrictive assumptions. It comes along with a good efficiency, illustrated by some selected simulation results comparing the performance of the proposed method with some existing techniques
Design and in vitro effectiveness evaluation of Echium amoenum extract loaded in bioadhesive phospholipid vesicles tailored for mucosal delivery
The Echium amoenum Fisch. and C.A. Mey. (E. amoenum) is an herb native from Iranian shrub, and its blue-violet flowers are traditionally used as medical plants. In the present study, an antioxidant phytocomplex was extracted from the flowers of E. amoenum by ultrasounds-assisted hydroalcoholic maceration. The main components, contained in the extract, have been detected using HPLC-DAD, and rosmarinic acid was found to be the most abundant. The antioxidant power of the extract along with the phenolic content were measured using colorimetric assays. The extract was loaded in liposomes, which were enriched adding different bioadhesive polymers (i.e., mucin, xanthan gum and carboxymethyl cellulose sodium salt) individually or in combination. The main physico-chemical properties (i.e. size, size distribution, surface charge) of the prepared vesicles were measured as well as their stability on storage. The viscosity of dispersion and the ability of vesicles to interact with mucus were evaluated measuring their stability in a mucin dispersion and mobility in a mucin film. The biocompatibility and the ability of the formulations to protect keratinocytes from damages caused by hydrogen peroxide and to promote the cell migration were measured in vitro
Entrapment of citrus limon var. Pompia essential oil or pure citral in liposomes tailored as mouthwash for the treatment of oral cavity diseases
This work aimed at developing a mouthwash based on liposomes loading Citrus limon var. pompia essential oil or citral to treat oropharyngeal diseases. Vesicles were prepared by dispersing phosphatidylcholine and pompia essential oil or citral at increasing amounts (12, 25 and 50 mg/mL) in water. Transparent vesicle dispersions were obtained by direct sonication avoiding the use of organic solvents. Cryogenic transmission electron microscopy (cryo-TEM) confirmed the formation of unilamellar, spherical and regularly shaped vesicles. Essential oil and citral loaded liposomes were small in size (~110 and ~100 nm, respectively) and negatively charged. Liposomes, especially those loading citral, were highly stable as their physico-chemical properties did not change during storage. The formulations were highly biocompatible against keratinocytes, were able to counteract the damages induced in cells by using hydrogen peroxide, and able to increase the rate of skin repair. In addition, liposomes loading citral at higher concentrations inhibited the proliferation of cariogenic bacterium
Extraction, characterization and incorporation of Hypericum scruglii extract in ad hoc formulated phospholipid vesicles designed for the treatment of skin diseases connected with oxidative stress
An extract of Hypericum scruglii, an endangered endemic plant of Sardinia (Italy), was prepared and characterized. It was loaded in special phospholipid vesicles, glycerosomes, which were modified by adding maltodextrin (glucidex) and a polymer (gelatin or hyaluronan). The corresponding liposomes were also prepared and used as reference. The vesicles disclosed suitable physicochemical features for skin delivery. Indeed, their mean diameter ranged from 120 to 160 nm, they were homogeneously dispersed (polydispersity index 0.30), and their zeta potential was highly negative (-45 mV). The vesicle dispersions maintained unchanged characteristics during 60 days of storage, were highly biocompatible, and were able to protect keratinocytes against damages due to oxidative stress induced by treating them with hydrogen peroxide. Vesicles were also capable of promoting cell proliferation and migration in vitro by means of a scratch wound assay. The results confirmed the fruitful delivery of the extract of H. scruglii in glycerosomes modified with glucidex and gelatin and their promising ability for skin protection and treatment
- …