Cytological studies of grapevine leafroll infected tissue: Further evidence of viroid etiology and improvement of diagnosis

In the cells of leafroll-infected grapevines mainly two kinds of inclusions were found, similar to those as previously described in citrus exocortis viroid-infected Gynura aurantiaca D. C. cells: cytoplasmic granular inclusions (presumably viroid derivatives or aggregations) and protein circular inclusions occupying the infected nucleoplasms. The observation of these inclusions could substitute the traditional leafroll indexing technique. The duration of this simple cytological diagnosis is approximately 30 min; it could be an important aid for the programs of sanitary selection or sanitation of the grapevine. The study confirms cytologically a recent paper based on b.iochemical techniques, contributing further evidence for the viroid etiology of this disease

Non-equilibrium dynamics of Andreev states in the Kondo regime

The transport properties of a quantum dot coupled to superconducting leads are analyzed. It is shown that the quasiparticle current in the Kondo regime is determined by the non-equilibrium dynamics of subgap states (Andreev states) under an applied voltage. The current at low bias is suppressed exponentially for decreasing Kondo temperature in agreement with recent experiments. We also predict novel interference effects due to multiple Landau-Zener transitions between Andreev states.Comment: Revtex4, 4 pages, 4 figure

Ionic behavior assessment of surface-active compounds from corn steep liquor by exchange resins

Depending on their ionic nature, biosurfactants can be classified as nonionic, anionic, cationic, or amphoteric. The ionic behavior of biosurfactants is an important characteristic that dictates their use in industrial applications. In this work, a biosurfactant extract obtained from corn steep liquor was subjected to anionic or cationic resins, in order to study the ionic behavior under different operational conditions using response surface methodology. The independent variables included in the study are the dilution of biosurfactant solution, the amount of cationic or anionic resin, and the extraction time, whereas the dependent variables studied consisted of the surface tension of biosurfactant aqueous solution, after contacting with anionic or cationic resin. The results showed that biosurfactant extracted from corn steep liquor is amphoteric, since both resins were able to entrap this biosurfactant, making it particularly suited for use in personal care preparations for sensitive skin.Peer ReviewedPostprint (author's final draft

Conductance properties of nanotubes coupled to superconducting leads: signatures of Andreev states dynamics

We present a combined experimental and theoretical analysis of the low bias conductance properties of carbon nanotubes coupled to superconducting leads. In the Kondo regime the conductance exhibits a zero bias peak which can be several times larger than the unitary limit in the normal case. This zero bias peak can be understood by analyzing the dynamics of the subgap Andreev states under an applied bias voltage. It is shown that the existence of a linear regime is linked to the presence of a finite relaxation rate within the system. The theory provides a good fitting of the experimental results.Comment: 6 revtex4 pages, 6 figures, to appear in SS

Essential oil-water emulsions containing a biosurfactant from Lactobacillus paracasei

[Excerpt] Surfactants play important roles in cosmetic products due to diverse properties including as emulsifier, foaming, wetting, detergency and solubilizer agents, among others. However, the market for beauty and personal care products based on natural ingredients has shown a relevant growth. In this sense, biosurfactants being non-toxic, biodegradable and ecofriendly natural compounds are suitable replacers of the chemical-based surfactants showing equal or better performances [1]. In addition, essential oils are natural ingredients extracted from plants that also are interesting ingredients for novel cosmetic formulations.The aim of this study was to formulate oil-water emulsions using a biosurfactant from Lactobacil/us paracasei in combination with several essential oils (wheat germ, almond, rosemary and jojoba oil). [...]Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BI0/04469/2013 unit, COMPETE 2020 (POCl-01-0145-FEDER-006684) and the project RECl/BBB-EBl/0179/2012 (FCOMP-01-0124-FEDER-027462

Micromagnetic Modeling of All-Optical Switching

[EN] The control of the magnetization at the microscale by pure optical means is fundamentally interesting and promises faster speeds for data storage devices. Although several experiments have shown that it is possible to locally reverse the magnetization of a ferromagnetic system by means of laser pulses, a completely theoretical description of these All Optical Switching processes is still lacking. Here, we develop an advanced micromagnetic solver that is applied to the numerical study of the All Optical Switching. The solver is based on the Landau-Lifshitz-Bloch equation that governs the dynamics of the magnetization coupled the microscopic three temperatures model, which describes the temporal evolution of the temperatures of the subsystems as caused by laser heating. The helicity-dependent magnetization switching is evaluated by a magneto-optical effective field caused by the Inverse Faraday Effect when a circularly polarized laser is applied to the sample. All the other usual terms of a full micromagnetic model are included (exchange, anisotropy, DMI…). As a test, the model is used to describe the local magnetization switching of thin film samples with high perpendicular anisotropy. The results are in good agreement with available experimental observations.MAT2014- 52477-C5-4-P, MAT2017-87072-C4-1-P, and MAT2017-90771-REDT from the Spanish government SA090U16 and SA299P18 from the Junta de Castilla y Leon

Antimicrobial study of biosurfactants from Lactobacillus strains against skin pathogens

[Excerpt] Human skin microflora is composed by resident1 temporarily resident and transient microbial species. Therefore, gram-positive bacteria from the genera Propionibacterium, Staphylococcus, Micrococcus, Corynebaderium and Acinetobacter are the majority microorganisms present in the resident microflora [1 ]. For instance, Staphylococcus epidermidis is the main constituent of skin microflora, which protects the human skin from infections; whereas Staphylococcus aureus is a common transient species, which causes skin infections [2]. Anti-bacterial preservatives such as triclosan, methylparaben or bronopol, among others, are currently used as ingredients in the skin and oral care cosmetic products. However, there is a growing demand for cosmetics free of synthetic preservatives [3]. In this sense, biosurfactants from lactic acid bacteria, which are generally recognized as safe by the American Food and Drug Administration, are natural compounds that exhibit antimicrobial activity and therefore, could be used as an alternative to the chemically synthetized preservatives. The aim of this study was to evaluate the antimicrobial activity of biosurfactants obtained from two different Lactobacillus strains (L. pentosus and L. paracasef) against skin pathogenic microorganisms. [...]Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BI0/04469/2013 unit, COMPETE 2020 (POCl-01-0145-FEDER-006684) and the project RECl/BBB-EBl/0179/2012 (FCOMP-01-0124-FEDER-027462

New approach on the bioconversion of vineyard pruning waste into surface-active compounds by Lactobacillus paracasei

Strategic funding of UID/BIO/04469/2013 unit and project ref RECI/BBB-EBI/0179/2012 (project number FCOMP-01-0124-FEDER-027462) and Xanel Vecino post-doctoral grant (ref SFRH/BPD/101476/2014) funded by Fundação para a Ciência e a Tecnologia, Portuga

Potential applications of multifunctional extract obtained from corn industry in food packaging

[Excerpt] Nowadays, in the food industry exists an increased demand, by the consumers, of natural additives that can replace those chemical additives obtained from non renewable resources. In this work extracts with surfactant and antioxidant properties were obtained from corn steep liquor (CSl) with potential applications in food packaging. the extraction process was carried out using ethyl acetate and the operational conditions consisted of: CSl/ethyl acetate 1:3 (v/v), at 25°C during 45 min with agitation system at 150 rpm. the antioxidant activity of the extract was determined by the dPPh (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method; whereas the surface active properties was evaluated by the wilhelmy plate method in a force tensiometer with a platinum plate (easy dyne k20, kruSS gmbh), at room temperature. Fatty acid composition of extract was analyzed by gas chromatography coupled to a mass spectrometer (Bruker Scion 451-gC). [...