3,362 research outputs found

    Instabilities and the roton spectrum of a quasi-1D Bose-Einstein condensed gas with dipole-dipole interactions

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    We point out the possibility of having a roton-type excitation spectrum in a quasi-1D Bose-Einstein condensate with dipole-dipole interactions. Normally such a system is quite unstable due to the attractive portion of the dipolar interaction. However, by reversing the sign of the dipolar interaction using either a rotating magnetic field or a laser with circular polarization, a stable cigar-shaped configuration can be achieved whose spectrum contains a `roton' minimum analogous to that found in helium II. Dipolar gases also offer the exciting prospect to tune the depth of this `roton' minimum by directly controlling the interparticle interaction strength. When the minimum touches the zero-energy axis the system is once again unstable, possibly to the formation of a density wave.Comment: 7 pages, 6 figures. Special Issue: "Ultracold Polar Molecules: Formation and Collisions

    Mild AgOTf Catalyzed Synthesis of 1-Carbosubstituted-isochromenes

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    One of the most efficient methods for the construction of 1-substituted isochromenes (and related heteroaryl compounds such as pyrano[4,3-b]pyridines) is the metal catalyzed regioselective domino cycloisomerization/nucleophilic addition reaction of a properly substituted 2-alkynyl(hetero)arylaldehyde in the presence of a suitable nucleophile. The reaction with oxygen nucleophiles is the most studied and several metal catalyst, i.e., Pd(II), Cu(I), Ag(I), Au(I) and In(III), demonstrated to be effective for synthesis of 1-alkoxyisochromenes. Conversely, the reaction with carbon nucleophiles, and in particular with enolizable carbonyl compounds, is relatively less investigated. In connection with our ongoing interest in the development of silver catalysed domino approaches involving alkyne derivatives, we report here a silver catalyzed domino approach to isochromenes starting from 2-alkynyl(hetero)arylaldehydes and enolizable carbonyl compounds. The reaction yields range from fair to very good. The reaction mechanism is also investigated and the formation of by-products discussed

    A Review of the Potential Benefits of Plants Producing Berries in Skin Disorders

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    During the last 30 years, berries have gained great attention as functional food against several risk factors in chronic diseases. The number of related publications on Pubmed rose from 1000 items in 1990 to more than 11,000 in 2019. Despite the fact that a common and clear definition of "berries" is not shared among different scientific areas, the phytochemical pattern of these fruits is mainly characterized by anthocyanins, flavanols, flavonols, and tannins, which showed antioxidant and anti-inflammatory properties in humans. Skin insults, like wounds, UV rays, and excessive inflammatory responses, may lead to chronic dermatological disorders, conditions often characterized by long-term treatments. The application of berries for skin protection is sustained by long traditional use, but many observations still require a clear pharmacological validation. This review summarizes the scientific evidence, published on EMBASE, MEDLINE, and Scholar, to identify extraction methods, way of administration, dose, and mechanism of action of berries for potential dermatological treatments. Promising in vitro and in vivo evidence of Punica granatum L. and Vitis vinifera L. supports wound healing and photoprotection, while Schisandra chinensis (Turcz.) Baill. and Vaccinium spp. showed clear immunomodulatory effects. Oral or topical administrations of these berries justify the evaluation of new translational studies to validate their efficacy in humans

    The Dynamics of Poor Systems of Galaxies

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    We assemble and observe a sample of poor galaxy systems that is suitable for testing N-body simulations of hierarchical clustering (Navarro, Frenk, & White 1997; NFW) and other dynamical halo models (e.g., Hernquist 1990). We (1) determine the parameters of the density profile rho(r) and the velocity dispersion profile sigma(R), (2) separate emission-line galaxies from absorption-line galaxies, examining the model parameters and as a function of spectroscopic type, and (3) for the best-behaved subsample, constrain the velocity anisotropy parameter, beta, which determines the shapes of the galaxy orbits. The NFW universal profile and the Hernquist (1990) model both provide good descriptions of the spatial data. In most cases an isothermal sphere is ruled out. Systems with declining sigma(R) are well-matched by theoretical profiles in which the star-forming galaxies have predominantly radial orbits (beta > 0); many of these galaxies are probably falling in for the first time. There is significant evidence for spatial segregation of the spectroscopic classes regardless of sigma(R).Comment: 36 pages, 20 figures, and 5 tables. To appear in the Astrophysical Journa

    Short-Term Anxiolytic and Pro-Hypnotic Actvity of a Tryptic Hydrolysate of Bovine Αs1-Casein in Patients with Anxiety Spectrum Disorders

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    We conducted a prospective open-label study with 100 outpatients who had sought psychiatric consult in private clinical practice for anxiety/sleep in subthreshold/full blown DSM-IV Anxiety Spectrum Disorders. Clinicians, prescribed for 4 weeks a dietary supplement based on a formulation containing \u3b1-casozepine peptide 300 mg/day. The comparison of all rating scales mean scores reported at T0 versus T1 showed a statistically significant decrease (p<0.001). In Clinical Global Impression scale, the 54% of the sample was found to be much improved, 27% minimally improved and 19% showed no change. The 64% of the sample reported an anxiolytic effect, and among the 64 patients with sleep disorders, the 51.5% reported a pro-hypnotic effect. Considering patients in monotherapy with the dietary supplement, an anxiolytic effect was observed in 69.7% while a prohypnotic effect was observed in the 62.5% of the sample. No side-effects were reported during the treatment with no drop-out

    Rhus coriaria l. Fruit extract prevents UV-A-induced genotoxicity and oxidative injury in human microvascular endothelial cells

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    Rhus coriaria L. (sumac) is a small plant widely diffused in the Mediterranean region. Its fruit are often consumed as a spice but are also present in traditional medicine of several countries. Recently, interest in this plant has increased and many scientific works reported its beneficial effects including antioxidant and anti-inflammatory properties. Plant extracts can be successfully used against ultraviolet rays, which are able to reach and damage the human skin; however, sumac extracts were never applied to this usage. Thus, in this study, we used a macerated ethanol extract of Rhus coriaria L. dried fruit (mERC) to demonstrate its preventive role against the damage induced by ultraviolet-A rays (UV-A) on microvascular endothelial cells (HMEC-1). In vitro effects of the extract pre-treatment and UV-A exposure were evaluated in detail. The antioxidant capacity was assessed by reactive oxygen species (ROS) formation and cellular antioxidant activity measurement. Genoprotective effects of mERC were investigated as well. Our findings indicate that the extract acts as a cell cycle inhibitor or apoptosis inducer, according to the level of damage. The present work provides new insights into the usage of Rhus coriaria extracts against skin injuries

    Asymptotics for the number of eigenvalues of three-particle Schr\"{o}dinger operators on lattices

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    We consider the Hamiltonian of a system of three quantum mechanical particles (two identical fermions and boson)on the three-dimensional lattice Z3\Z^3 and interacting by means of zero-range attractive potentials. We describe the location and structure of the essential spectrum of the three-particle discrete Schr\"{o}dinger operator Hγ(K),H_{\gamma}(K), KK being the total quasi-momentum and γ>0\gamma>0 the ratio of the mass of fermion and boson. We choose for γ>0\gamma>0 the interaction v(γ)v(\gamma) in such a way the system consisting of one fermion and one boson has a zero energy resonance. We prove for any γ>0\gamma> 0 the existence infinitely many eigenvalues of the operator Hγ(0).H_{\gamma}(0). We establish for the number N(0,γ;z;)N(0,\gamma; z;) of eigenvalues lying below z<0z<0 the following asymptotics limz0N(0,γ;z)logz=U(γ). \lim_{z\to 0-}\frac{N(0,\gamma;z)}{\mid \log \mid z\mid \mid}={U} (\gamma) . Moreover, for all nonzero values of the quasi-momentum KT3K \in T^3 we establish the finiteness of the number N(K,γ;τess(K)) N(K,\gamma;\tau_{ess}(K)) of eigenvalues of H(K)H(K) below the bottom of the essential spectrum and we give an asymptotics for the number N(K,γ;0)N(K,\gamma;0) of eigenvalues below zero.Comment: 25 page
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