328 research outputs found

    Synthesis of dietetic structures lipids from spent coffee grounds crude oil catalyzed by commercial immobilized lipases and immobilized Rhizopus oryzae lipase on biochar and hybrid support

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    The aim of this study was the valorization of coffee industry residues, namely spent coffee grounds (SCG) as a source of oil, and silverskin (CS) as a source of both oil and biomass, under the concept of the circular economy. Therefore, crude oil from SCG was used to produce low-calorie structured lipids (SL) for food and pharmaceutical industries, and CS to produce biochar by pyrolysis for biotechnological uses. SL were obtained by acidolysis with caprylic or capric acid, or interesterification with ethyl caprylate or ethyl caprate, in solvent-free media, catalyzed by immobilized sn-1,3 regioselective lipases. Silverskin biochar (BIO) was directly used as enzyme carrier or to produce hybrid organic-silica (HB) supports for enzyme immobilization. Rhizopus oryzae lipase (ROL) immobilized on Amberlite (AMB), silica (SIL), BIO or HB, and the commercial immobilized Thermomyces lanuginosus (Lipozyme TL IM) and Rhizomucor miehei (Lipozyme RM IM) lipases were tested. Lipozyme RM IM showed better results in SL production than Lipozyme TLIM or ROL on BIO, SIL or HB. About 90% triacylglycerol conversion was attained after 7 h acidolysis or interesterification. Lipozyme RM IM was more stable in interesterification (80% and 65% activity with ethyl caprylate or ethyl caprate) than in acidolysis (first-order decay) after 10 reusesinfo:eu-repo/semantics/publishedVersio

    Solar dynamo model with nonlocal alpha-effect

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    The first results of the solar dynamo model that allows for the diamagnetic effect of inhomogeneous turbulence and the nonlocal alpha-effect due to the rise of magnetic loops are discussed. The nonlocal alpha-effect is not subject to the catastrophic quenching related to the conservation of magnetic helicity. Given the diamagnetic pumping, the magnetic fields are concentrated near the base of the convection zone, although the distributed-type model covers the entire thickness of the convection zone. The magnetic cycle period, the equatorial symmetry of the field, its meridional drift, and the polar-to-toroidal field ratio obtained in the model are in agreement with observations. There is also some disagreement with observations pointing the ways of improving the model.Comment: To appear in Astronomy Letters, 10 pages, 5 figure

    The model of dynamo with small number of modes and magnetic activity of T Tauri stars

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    The model that describes operation of dynamo in fully convective stars is presented. It is based on representation of stellar magnetic field as a superposition of finite number of poloidal and toroidal free damping modes. In the frame of adopted low of stellar differential rotation we estimated minimal value of dynamo number D, starting from which generation of cyclic magnetic field in stars without radiative core is possible. We also derived expression for period of the cycle. It was found that dynamo cycles of fully convective stars and stars with thin convective envelopes differ in a qualitative way: 1) distribution of spots over latitude during the cycle is different in these stars; 2) the model predicts that spot formation in fully convective stars should be strongly suppressed at some phases of the cycle. We have analyzed historical lightcurve of WTTS star V410 Tau and found that long term activity of the star is not periodic process. Rather one can speak about quasi cyclic activity with characteristic time of ∼4\sim 4 yr and chaotic component over imposed. We concluded also that redistribution of cool spots over longitude is the reason of long term variations of V410 Tau brightness. It means that one can not compare directly results of photometric observations with predictions of our axially symmetric (for simplicity) model which allows to investigate time evolution of spot's distribution over latitude. We then discuss what kind of observations and in which way could be used to check predictions of the dynamo theory.Comment: 18 pages, 5 figures, accepted to Astron. Let

    Non-PEGylated liposomes for convection-enhanced delivery of topotecan and gadodiamide in malignant glioma: initial experience

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    Convection-enhanced delivery (CED) of highly stable PEGylated liposomes encapsulating chemotherapeutic drugs has previously been effective against malignant glioma xenografts. We have developed a novel, convectable non-PEGylated liposomal formulation that can be used to encapsulate both the topoisomerase I inhibitor topotecan (topoCEDβ„’) and paramagnetic gadodiamide (gadoCEDβ„’), providing an ideal basis for real-time monitoring of drug distribution. Tissue retention of topoCED following single CED administration was significantly improved relative to free topotecan. At a dose of 10Β ΞΌg (0.5Β mg/ml), topoCED had a half-life in brain of approximately 1Β day and increased the area under the concentration–time curve (AUC) by 28-fold over free topotecan (153.8 vs. 5.5Β ΞΌgΒ day/g). The combination of topoCED and gadoCED was found to co-convect well in both naΓ―ve rat brain and malignant glioma xenografts (correlation coefficients 0.97–0.99). In a U87MG cell assay, the 50% inhibitory concentration (IC50) of topoCED was approximately 0.8Β ΞΌM at 48 and 72Β h; its concentration–time curves were similar to free topotecan and unaffected by gadoCED. In a U87MG intracranial rat xenograft model, a two-dose CED regimen of topoCED co-infused with gadoCED greatly increased median overall survival at dose levels of 0.5Β mg/ml (29.5Β days) and 1.0Β mg/ml (33.0Β days) vs. control (20.0Β days; PΒ <Β 0.0001 for both comparisons). TopoCED at higher concentrations (1.6Β mg/ml) co-infused with gadoCED showed no evidence of histopathological changes attributable to either agent. The positive results of tissue pharmacokinetics, co-convection, cytotoxicity, efficacy, and lack of toxicity of topoCED in a clinically meaningful dose range, combined with an ideal matched-liposome paramagnetic agent, gadoCED, implicates further clinical applications of this therapy in the treatment of malignant glioma

    Convection and Retro-Convection Enhanced Delivery: Some Theoretical Considerations Related to Drug Targeting

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    Delivery of drugs and macromolecules into the brain is a challenging problem, due in part to the blood–brain barrier. In this article, we focus on the possibilities and limitations of two infusion techniques devised to bypass the blood–brain barrier: convection enhanced delivery (CED) and retro-convection enhanced delivery (R-CED). CED infuses fluid directly into the interstitial space of brain or tumor, whereas R-CED removes fluid from the interstitial space, which results in the transfer of drugs from the vascular compartment into the brain or tumor. Both techniques have shown promising results for the delivery of drugs into large volumes of tissue. Theoretical approaches of varying complexity have been developed to better understand and predict brain interstitial pressures and drug distribution for these techniques. These theoretical models of flow and diffusion can only be solved explicitly in simple geometries, and spherical symmetry is usually assumed for CED, while axial symmetry has been assumed for R-CED. This perspective summarizes features of these models and provides physical arguments and numerical simulations to support the notion that spherical symmetry is a reasonable approximation for modeling CED and R-CED. We also explore the potential of multi-catheter arrays for delivering and compartmentalizing drugs using CED and R-CED

    Over 200,000 kilometers of free-flowing river habitat in Europe is altered due to impoundments

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    European rivers are disconnected by more than one million man-made barriers that physically limit aquatic species migration and contribute to modification of freshwater habitats. Here, a Conceptual Habitat Alteration Model for Ponding is developed to aid in evaluating the effects of impoundments on fish habitats. Fish communities present in rivers with low human impact and their broad environmental settings enable classification of European rivers into 15 macrohabitat types. These classifications, together with the estimated fish sensitivity to alteration of their habitat are used for assessing the impacts of six main barrier types (dams, weirs, sluices, culverts, fords, and ramps). Our results indicate that over 200,000 km or 10% of previously free-flowing river habitat has been altered due to impoundments. Although they appear less frequently, dams, weirs and sluices cause much more habitat alteration than the other types. Their impact is regionally diverse, which is a function of barrier height, type and density, as well as biogeographical location. This work allows us to foresee what potential environmental gain or loss can be expected with planned barrier management actions in rivers, and to prioritize management actions

    Interferon-Ξ± Abrogates Tolerance Induction by Human Tolerogenic Dendritic Cells

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    BACKGROUND: Administration of interferon-Ξ± (IFN-Ξ±) represents an approved adjuvant therapy as reported for malignancies like melanoma and several viral infections. In malignant diseases, tolerance processes are critically involved in tumor progression. In this study, the effect of IFN-Ξ± on tolerance induction by human tolerogenic dendritic cells (DC) was analyzed. We focussed on tolerogenic IL-10-modulated DC (IL-10 DC) that are known to induce anergic regulatory T cells (iTregs). METHODOLOGY/PRINCIPAL FINDINGS: IFN-Ξ± promoted an enhanced maturation of IL-10 DC as demonstrated by upregulation of the differentiation marker CD83 as well as costimulatory molecules. IFN-Ξ± treatment resulted in an increased capacity of DC to stimulate T cell activation compared to control tolerogenic DC. We observed a strengthened T cell proliferation and increased IFN-Ξ³ production of CD4(+) and CD8(+) T cells stimulated by IFN-Ξ±-DC, demonstrating a restoration of the immunogenic capacity of tolerogenic DC in the presence of IFN-Ξ±. Notably, restimulation experiments revealed that IFN-Ξ± treatment of tolerogenic DC abolished the induction of T cell anergy and suppressor function of iTregs. In contrast, IFN-Ξ± neither affected the priming of iTregs nor converted iTregs into effector T cells. CONCLUSIONS/SIGNIFICANCE: IFN-Ξ± inhibits the induction of T cell tolerance by reversing the tolerogenic function of human DC

    Anatomical Differences Determine Distribution of Adenovirus after Convection-Enhanced Delivery to the Rat Brain

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    Background: Convection-enhanced delivery (CED) of adenoviruses offers the potential of widespread virus distribution in the brain. In CED, the volume of distribution (Vd) should be related to the volume of infusion (Vi) and not to dose, but when using adenoviruses contrasting results have been reported. As the characteristics of the infused tissue can affect convective delivery, this study was performed to determine the effects of the gray and white matter on CED of adenoviruses and similar sized super paramagnetic iron oxide nanoparticles (SPIO). Methodology/Principal Findings: We convected AdGFP, an adenovirus vector expressing Green Fluorescent Protein, a virus sized SPIO or trypan blue in the gray and white matter of the striatum and external capsule of Wistar rats and towards orthotopic infiltrative brain tumors. The resulting Vds were compared to Vi and transgene expression to SPIO distribution. Results show that in the striatum Vd is not determined by the Vi but by the infused virus dose, suggesting diffusion, active transport or receptor saturation rather than convection. Distribution of virus and SPIO in the white matter is partly volume dependent, which is probably caused by preferential fluid pathways from the external capsule to the surrounding gray matter, as demonstrated by co-infusing trypan blue. Distant tumors were reached using the white matter tracts but tumor penetration was limited. Conclusions/Significance: CED of adenoviruses in the rat brain and towards infiltrative tumors is feasible when regional anatomical differences are taken into account while SPIO infusion could be considered to validate proper catheter positioning and predict adenoviral distribution

    Characterization of Italian honeys (Marche Region) on the basis of their mineral content and some typical quality parameters

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    <p>Abstract</p> <p>Background</p> <p>The characterization of three types of Marche (Italy) honeys (Acacia, Multifloral, Honeydew) was carried out on the basis of the their quality parameters (pH, sugar content, humidity) and mineral content (Na, K, Ca, Mg, Cu, Fe, and Mn). Pattern recognition methods such as principal components analysis (PCA) and linear discriminant analysis (LDA) were performed in order to classify honey samples whose botanical origins were different, and identify the most discriminant parameters. Lastly, using ANOVA and correlations for all parameters, significant differences between diverse types of honey were examined.</p> <p>Results</p> <p>Most of the samples' water content showed good maturity (98%) whilst pH values were in the range 3.50 – 4.21 confirming the good quality of the honeys analysed. Potassium was quantitatively the most relevant mineral (mean = 643 ppm), accounting for 79% of the total mineral content. The Ca, Na and Mg contents account for 14, 3 and 3% of the total mineral content respectively, while other minerals (Cu, Mn, Fe) were present at very low levels. PCA explained 75% or more of the variance with the first two PC variables. The variables with higher discrimination power according to the multivariate statistical procedure were Mg and pH. On the other hand, all samples of acacia and honeydew, and more than 90% of samples of multifloral type have been correctly classified using the LDA. ANOVA shows significant differences between diverse floral origins for all variables except sugar, moisture and Fe.</p> <p>Conclusion</p> <p>In general, the analytical results obtained for the Marche honeys indicate the products' high quality. The determination of physicochemical parameters and mineral content in combination with modern statistical techniques can be a useful tool for honey classification.</p

    Nonviral Approaches for Neuronal Delivery of Nucleic Acids

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    The delivery of therapeutic nucleic acids to neurons has the potential to treat neurological disease and spinal cord injury. While select viral vectors have shown promise as gene carriers to neurons, their potential as therapeutic agents is limited by their toxicity and immunogenicity, their broad tropism, and the cost of large-scale formulation. Nonviral vectors are an attractive alternative in that they offer improved safety profiles compared to viruses, are less expensive to produce, and can be targeted to specific neuronal subpopulations. However, most nonviral vectors suffer from significantly lower transfection efficiencies than neurotropic viruses, severely limiting their utility in neuron-targeted delivery applications. To realize the potential of nonviral delivery technology in neurons, vectors must be designed to overcome a series of extra- and intracellular barriers. In this article, we describe the challenges preventing successful nonviral delivery of nucleic acids to neurons and review strategies aimed at overcoming these challenges
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