216 research outputs found

    The Use of Industrial Waste for the Bioremediation of Water Used in Industrial Processes

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    Recently the interest in the remediation of liquid effluents from industries such as paint manufacturing, leather tanning, etc. has increased, because the quality of the water used in these processes is highly compromised and is generally discarded without any process of purification, causing an inadequate use of water and contributing to the hydric stress of the planet. Therefore, it is necessary to find alternatives for the remediation of water used in industrial processes; one of the methods that has been widely accepted given its high efficiency, low cost, and versatility compared to others is the bioadsorption using materials derived from various processes used for the elimination of metals such as Cr, Co, Cu, Ni, etc. from liquid effluents. Among the materials used for this purpose are rice husk, orange, and wheat as well as apatite (hydroxyapatite and brushite), derived from animal bones, which have shown good capacity (>90%) to adsorb metals from aqueous solutions. Through the characterization by DRX, FTIR, and SEM, of the brushite and studies in equilibrium and kinetics of adsorption, it has been demonstrated that this material has a good capacity to remove metals present in water

    Energy transfer in two-wave mixing quasi-degenerated in photorefractive crystals

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    Wave equations describing the quasi-degenerated two-beam coupling in the photorefractive crystals for high frequency gratings have been solved. In the case of the quasi-degenerate two-beam coupling, equations depend upon the coupling coefficient, the response time of the medium, the input beams frequencies, the absorption coefficient and the input intensity ratio. The response time of the medium is function of the diffusion field, the drift field, the saturation field and the concentration ratio, i.e., the ratio between NA density of acceptor impurities and ND density of donor impurities. The effect of these parameters on the gain has been studied in details.Facultad de Ciencias Exacta

    Fruit peels as sources of bioactive compounds with antioxidant and antimicrobial properties

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    Recently, a major interest in searching for phytochemicals with nutritional and pharmaceutical purposes has arisen. In this regard, it is known that polyphenols present antioxidant properties as well as an inhibitory effect against some kinds of microorganisms. The aim of this study was to obtain aqueous-ethanolic extracts from peels of avocado, cocoa bean, coconut and cactus pear by ultrasound-assisted extraction. The extracts were characterized in terms of phenolics (Folin-Ciocalteu reagent), antioxidant potential (ferric reducing/antioxidant power assay), radical-scavenging ability (2,2-diphenyl-2-picrylhydrazyl free radical assay), and antimicrobial activity against Staphylococcus aureus, Shigella dysenteriae and Candida albicans (disk diffusion test). The results revealed that the avocado peel extract had the highest phenol content (36.5 mg EAG g-1 dry weight), the highest antioxidant activity (141.2 mME Trolox g-1 dry weight) and the lowest IC50 value (59 ppm). Furthermore, avocado and coconut peels demonstrated an inhibitory effect against the tested microorganisms. Highlights Bioactive compounds from fruit by-products were obtained by ultrasound-assisted extraction. A positive correlation between phenolics and antioxidant activity was observed. Extracts with higher antioxidant activity were more active against the tested microorganisms. Fruit by-products could represent an important source of compounds with antioxidant and antimicrobial properties.Recently, a major interest in searching for phytochemicals with nutritional and pharmaceutical purposes has arisen. In this regard, it is known that polyphenols present antioxidant properties as well as an inhibitory effect against some kinds of microorganisms. The aim of this study was to obtain aqueous-ethanolic extracts from peels of avocado, cocoa bean, coconut and cactus pear by ultrasound-assisted extraction. The extracts were characterized in terms of phenolics (Folin-Ciocalteu reagent), antioxidant potential (ferric reducing/antioxidant power assay), radical-scavenging ability (2,2-diphenyl-2-picrylhydrazyl free radical assay), and antimicrobial activity against Staphylococcus aureus, Shigella dysenteriae and Candida albicans (disk diffusion test). The results revealed that the avocado peel extract had the highest phenol content (36.5 mg EAG g-1 dry weight), the highest antioxidant activity (141.2 mME Trolox g-1 dry weight) and the lowest IC50 value (59 ppm). Furthermore, avocado and coconut peels demonstrated an inhibitory effect against the tested microorganisms. Highlights Bioactive compounds from fruit by-products were obtained by ultrasound-assisted extraction. A positive correlation between phenolics and antioxidant activity was observed. Extracts with higher antioxidant activity were more active against the tested microorganisms. Fruit by-products could represent an important source of compounds with antioxidant and antimicrobial properties

    On the mechanical behaviour of PEEK and HA cranial implants under impact loading

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    The human head can be subjected to numerous impact loadings such as those produced by a fall or during sport activities. These accidents can result in skull fracture and in some complex cases, part of the skull may need to be replaced by a biomedical implant. Even when the skull is not damaged, such accidents can result in brain swelling treated by decompressive craniectomy. Usually, after recovery, the part of the skull that has been removed is replaced by a prosthesis. In such situations, a computational tool able to analyse the choice of prosthesis material depending on the patient's specific activity has the potential to be extremely useful for clinicians. The work proposed here focusses on the development and use of a numerical model for the analysis of cranial implants under impact conditions. In particular, two main biomaterials commonly employed for this kind of prosthesis are polyether-ether-ketone (PEEK) and macroporous hydroxyapatite (HA). In order to study the suitability of these implants, a finite element head model comprising scalp, skull, cerebral falx, cerebrospinal fluid and brain tissues, with a cranial implant replacing part of the skull has been developed from magnetic resonance imaging data. The human tissues and these two biocompatible materials have been independently studied and their constitutive models are provided here. A computational model of the human head under impact loading is then implemented and validated, and a numerical comparison of the mechanical impact response of PEEK and HA implants is presented. This comparison was carried out in terms of the effectiveness of both implants in ensuring structural integrity and preventing traumatic brain injury.The researchers of the University Carlos III are indebted to the Ministerio de Economía y Competitividad de España (Project DPI2014-57989-P) and Vicerrectorado de Política Científica UC3M (Project 2013-00219-002) for the financial support. A.J. acknowledges funding from the European Union's Seventh Framework Programme (FP7 2007–2013) ERC Grant Agreement No. 306587. MRI data were provided by the Human Connectome Project, WUMinn Consortium (Principal Investigators: David Van Essen and Kamil Ugurbil; 1U54MH091657) funded by the 16 NIH Institutes and Centers that support the NIH Blueprint for Neuroscience Research; and by the McDonnell Center for Systems Neuroscience at Washington University. Finally, we would like to thank Dr. S Barhli and Prof. J Marrow for valuable assistance with the X-ray tomography; the machine used was bought from EPSRC Grant EP/M02833X/1 “University of Oxford: experimental equipment upgrade”. Open Access funded by European Research Counci

    Medical imaging: Foundations and scope

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    Indexación: Scopus; Radalyc.En la actualidad es innegable la utilidad de las diversas modalidades de imagenología médica como apoyo clínico tanto en la generación de diagnósticos de un buen número de enfermedades como en la planeación de tratamientos tendientes a proporcionar una alternativa de solución a las personas que, por una u otra razón, manifiestan algún desequilibrio en su salud. Entre las modalidades imagenológicas que, frecuentemente, se utilizan en el ámbito médico se pueden mencionar: Ultrasonido (US), Resonancia Magnética (MRI), Tomografía Computarizada sencilla (CT) y multicapa (MSCT), Tomografía Computarizada por Emisión de Positrones (PET) y Tomografía Computarizada por Emisión de Fotones simples (SPECT). En este sentido, este artículo tiene como finalidad presentar una descripción ordenada, coherente y sistemática de cada una de las mencionadas modalidades y establecer la vinculación de la MSCT con situaciones clínicas íntimamente relacionadas con la anatomía cardiaca y procesos de hipertensión. La razón por la cual se hace énfasis en la MSCT es debido a que, por una parte, se cuenta con un número importante de bases de datos tanto de sujetos fisiológicos como de sujetos patológicos y, por la otra, que se tiene previsto presentar un conjunto de técnicas computacionales que serán exploradas en el desarrollo de futuras investigaciones en el contexto de aspectos anatómico-cardiológicos que influyen directa o indirectamente en la aparición, desarrollo y prevalencia de procesos hipertensivos.Nowdays, several forms of medical imaging are usefulness in clinical support for both diagnostics diseases generation and treatment planning designed to provide an alternative solution to people who, for one or another reason, manifest an imbalance in your health. Among the imaging modalities that frequently are used in the medical field may include: Ultrasound (US), magnetic resonance imaging (MRI), simple computed tomography (CT) and multilayer computed tomography (MSCT), CT positron emission tomography (PET) Computed tomography and single photon emission (SPECT). In this sense, this article presents an orderly, coherent and systematic description of these modalities and it establishes relationship with the MSCT modality and clinical situations closely related to cardiac anatomy and hypertension processes. The reason emphasis on MSCT is done is because, on the one hand, we have a large number of databases both physiological subjects and pathological subjects and, on the other, we plan to present a set of computational techniques that will be explored in future research, in the context of cardiologic anatomical aspects, with directly or indirectly influence in the emergence, development and prevalence of hypertensive processes.http://www.redalyc.org/articulo.oa?id=5594990700

    VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

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    VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro

    Medios de comunicación y derecho a la información en Jalisco 2013

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    En el primer apartado, dedicado al sistema de medios en general, se presentan tres artículos: “Nuevos medios de comunicación en Jalisco”, “c7 ¿medio público o vocero del gobierno?” y “Réquiem por un ombudsman”. El segundo apartado está dedicado al tema de la libertad de expresión; se presentan aquí dos textos: “La vulnerabilidad en un ambiente de cambio. Los ataques a los medios de comunicación en Jalisco durante el año” y “Violaciones a la libertad de expresión de periodistas y trabajadores de medios en Jalisco, 1995-2013”. En el apartado “Derecho a la información, comunicación y política” se ofrecen cuatro textos de índole muy diversa: “La estrategia de comunicación del Gobierno del Estado”, “Diálogos públicos: la discusión de una nueva ley de transparencia para Jalisco”, “Cuando un niño desaparece, el peor enemigo es el tiempo…”, sobre la alerta Amber, y “2013: un año marcado por despidos en diversos periódicos de Guadalajara”. En la sección “Los que se fueron” se presenta la semblanza de Felipe Vicencio. Y en el apartado de “La investigación del observatorio de medios” se comparten los resultados de un trabajo sobre los columnistas de opinión jaliscienses que escriben en la prensa local.ITESO, A.C

    Characterization of Indoor Extremely Low Frequency and Low Frequency Electromagnetic Fields in the INMA-Granada Cohort

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    Objective: To characterize the exposure to electric fields and magnetic fields of non-ionizing radiation in the electromagnetic spectrum (15 Hz to 100 kHz) in the dwellings of children from the Spanish Environment and Childhood-“INMA” population-based birth cohort. Methodology: The study sample was drawn from the INMA-Granada cohort. Out of 300 boys participating in the 9–10 year follow-up, 123 families agreed to the exposure assessment at home and completed a specific ad hoc questionnaire gathering information on sources of non-ionizing radiation electric and magnetic fields inside the homes and on patterns of use. Long-term indoor measurements were carried out in the living room and bedroom. Results: Survey data showed a low exposure in the children's homes according to reference levels of the International Commission on Non-Ionizing Radiation Protection but with large differences among homes in mean and maximum values. Daytime electrostatic and magnetic fields were below the quantification limit in 78.6% (92 dwellings) and 92.3% (108 dwellings) of houses, with an arithmetic mean value (± standard deviation) of 7.31±9.32 V/m and 162.30±91.16 nT, respectively. Mean magnetic field values were 1.6 lower during the night than the day. Nocturnal electrostatic values were not measured. Exposure levels were influenced by the area of residence (higher values in urban/semi-urban versus rural areas), type of dwelling, age of dwelling, floor of the dwelling, and season. Conclusion: Given the greater sensitivity to extremely low-frequency electromagnetic fields of children and following the precautionary principle, preventive measures are warranted to reduce their exposure.This work was supported by the Spanish Ministry of Health (CIBERESP and FIS PI11/0610) and the Andalusia Regional Government, Council of Innovation, Science and Enterprise (Excellence Project P09-CTS-5488) and Council of Health (SAS PI-0675-2010)

    Specific Cell Targeting Therapy Bypasses Drug Resistance Mechanisms in African Trypanosomiasis

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    African trypanosomiasis is a deadly neglected disease caused by the extracellular parasite Trypanosoma brucei. Current therapies are characterized by high drug toxicity and increasing drug resistance mainly associated with loss-of-function mutations in the transporters involved in drug import. The introduction of new antiparasitic drugs into therapeutic use is a slow and expensive process. In contrast, specific targeting of existing drugs could represent a more rapid and cost-effective approach for neglected disease treatment, impacting through reduced systemic toxicity and circumventing resistance acquired through impaired compound uptake. We have generated nanoparticles of chitosan loaded with the trypanocidal drug pentamidine and coated by a single domain nanobody that specifically targets the surface of African trypanosomes. Once loaded into this nanocarrier, pentamidine enters trypanosomes through endocytosis instead of via classical cell surface transporters. The curative dose of pentamidine-loaded nanobody-chitosan nanoparticles was 100-fold lower than pentamidine alone in a murine model of acute African trypanosomiasis. Crucially, this new formulation displayed undiminished in vitro and in vivo activity against a trypanosome cell line resistant to pentamidine as a result of mutations in the surface transporter aquaglyceroporin 2. We conclude that this new drug delivery system increases drug efficacy and has the ability to overcome resistance to some anti-protozoal drugs.JAGS was funded by the European Union, grant FP7-HEALTH-2007-B-2.3.4-1.223048, NANOTRYP and Ministerio de Economía y Competitividad, Spain Plan Nacional de Investigación grant SAF2011- 30528. JLA was funded by Instituto de Salud Carlos III, Spain, grant FIS. 11/02571. HPdK was supported by a grant from the Medical Research Council (84733)
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