Some Existence Results for a Paneitz Type Problem Via the Theory of Critical Points at Infinity

In this paper a fourth order equation involving critical growth is considered under Navier boundary condition. We give some topological conditions on a given function to ensure the existence of solutions. Our methods involve the study of the critical points at infinity and their contribution to the topology of the level sets of the associated Euler Lagrange functionalComment: 26 page

Acoustical and thermodynamic study of binary mixture cyclohexane-methanol using ultrasonic interferometer at different temperatures

The ultrasonic velocity (U) mass density (ρ) and shear viscosity (η) of the binary liquid mixtures of cyclohexane-methanol have been determined experimentally in the single-phase region and over the whole composition range at temperature range (T = 321.15 to 325.15 K). The experimental measurements of these properties have been carried out at atmospheric pressure, for a constant frequency 2 MHz. From these experimental data values, various acoustic and thermodynamic parameters namely adiabatic compressibility (βs), acoustic impedance (Z), intermolecular free length (Lf), relaxation time (τ), molar volume (Vm), free volume (Vf), internal pressure (πi), attenuation (α/f2), Gibb’s energy (ΔG), and cohesive energy (CE) have been calculated. Also their excess values have been calculated. All these parameters and their excess values have been interpreted in terms of molecular interaction such as dipole-dipole and dipole induced dipole interactions through hydrogen bonding between components of binary liquid mixture

In vitro screening of soil bacteria for inhibiting phytopathogenic fungi

At present, the greatest interest resides with the development and application of specific biocontrol agent for the control of diseases on plant and this form the focus of this work. Several soil bacteria were evaluated in vitro for their effectiveness on the basis of their ability to suppress fungi in plate inhibition assays. 51 strains of 12 bacterial species were performed against 12 strains of 10 phytopathogenic mould species. Almost all soil bacteria species; but about 50% of the bacteria strains, showed an antagonistic activity against at least one phytopathogenic fungus. Sphingomonans spp was the only specie that did not show any antagonistic effect to all fungi. Bradyrhizobium japonicum could highly inhibit the mycelial growth of five moulds (Botrytis cinerea, Phoma medicaginis, Fusarium verticilloides, Rhizoctonia solani and Phytophtora infestans) with a growth inhibition varying between 12.38 and 37.61%. 12 Bacillus strains and five Pseudomonas strains were antagonistic to the major phytopathogenic moulds used in this trial. Bacillus subtilis exhibited strong antagonism against fungi both from cultural medium and from sterile filtrate. Results show that bacterial suspension and bacterial supernatant did not operate in the same way. Supernatant from bacterial strains seemed to be efficient against phytopathogenic moulds. The mycelial growth of R. solani, P. medicaginis and F. verticilloides was inhibited by 12-fold dilution of the supernatant from B. japonicum. The latter draws a conclusion that bacteria isolated from soil are promising natural biocontrol agents and should be further studied and tested for the control of numerous plant diseases. Additional studies are required to definitively determine their mode of antifungal action, safety and biocompatibility.Keywords: Bacteria, phytopathogenic fungi, antagonis

Adsorption of nucleotides on biomimetic apatite: The case ofadenosine 5' triphosphate (ATP)

ATP is a well-known energy supplier in cells. The idea to associate ATP to pharmaceutical formulations/biotechnological devices to promote cells activity by potentially modulating their microenvironment thus appears as an appealing novel approach. Since biomimetic nanocrystalline apatites have shown great promise for biomedical applications (bone regeneration, cells diagnostics/therapeutics,...), thanks to a high surface reactivity and an intrinsically high biocompatibility, the present contribution was aimed at exploring ATP/apatite interactions. ATP adsorption on a synthetic carbonated nanocrystalline apatite preliminarily characterized (by XRD, FTIR, Raman, TG-DTA and SEM-EDX) was investigated in detail, pointing out a good agreement with Sips isothermal features. Adsorption characteristics were compared to those previously obtained on monophosphate nucleotides (AMP, CMP), unveiling some specificities. ATP was found to adsorb effectively onto biomimetic apatite: despite smaller values of the affinity constant KS and the exponential factor m, larger adsorbed amounts were reached for ATP as compared to AMP for any given concentration in solution. m<1 suggests that the ATP/apatite adsorption process is mostly guided by direct surface bonding rather than through stabilizing intermolecular interactions. Although standard ∆Gads° was estimated to only -4kJ/mol, the large value of Nmax led to significantly negative effective ∆Gads values down to -33kJ/mol, reflecting the spontaneous character of adsorption process. Vibrational spectroscopy data (FTIR and Raman) pointed out spectral modifications upon adsorption, confirming chemical-like interactions where both the triphosphate group of ATP and its nucleic base were involved. The present study is intended to serve as a basis for future research works involving ATP and apatite nanocrystals/nanoparticles in view of biomedical applications (e.g. bone tissue engineering, intracellular drug delivery,...)

Chemical Composition and Antioxidant Activity of Essential Oil from the Aerial Parts of Teucrium luteum (Mill.) Degen subsp. flavovirens (Batt.) Greuter &amp; Burdet Growing Wild in Tunisia

Essential oils (EOs), the odorous and volatile products of a plant's secondary metabolism, have wide applications in folk medicine, in food flavoring and preservation, and in fragrance industries. The aim of this study was to analyze the chemical composition of the EO from the aerial parts (including the inflorescences) of wild Teucrium luteum subsp. flavovirens from Tunisia. The EO obtained by the hydrodistillation of air-dried plant material in a Clevenger-type apparatus was analyzed using gas chromatography coupled with mass spectrometry (GC-MS). Fifty-three components representing 83.9% of the total constituents were identified. The EO of T. luteum subsp. flavovirens is characterized by the presence of beta-elemol (7.2%), (+)-alpha-pinene (6%), beta-eudesmol (5.5%), guaiol (4.2%), alpha-bisabolol (4.2%), and beta-caryophyllene (4.1%) as principal chemical components. In vitro (DPPH and beta-carotene bleaching assays), it showed significantly higher radical scavenging and antioxidant properties than the reference compound, BHT. To the best of our knowledge, this is the first report describing the composition and antioxidant properties of the EO from Tunisian T. luteum subsp. flavovirens. Our preliminary data will help to valorize this potentially useful plant species from Tunisia and represent a starting point for further studies on its volatile fraction

Chronic crude garlic-feeding modified adult male rat testicular markers: mechanisms of action

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens