Problems of Silica Scaling at Cerro Prieto Geothrmal Power Station

In the Cerro Prieto Geothermal field, where the predominant fluid in the reservoir is water, they have had problems with silica and other deposits in the first exploration wells as well as in production wells. Scaling problems have also been encountered in silencers, cyclone separators, drains, water pipes, etc. Some scale problems have also been encountered in the turbine blades of the geothermal electric plant. Most of these problems have been solved by corrective procedures which, in some cases, have turned into routine. Scale deposition is a problem that certainly diminishes the useful capacity of geothermal fluids with water predominance, but it does not actually endanger the installations, since this problem is under control

Indexing and summary services, an undervalued opportunity to improve the visibility and dissemination of articles published in Latin American scientific journals: DOAJ case

El objetivo de la presente investigación se centró en analizar el conjunto de datos provistos por el Directorio de Revistas de Acceso Abierto (DOAJ, por sus siglas en ingles), respecto a criterios transversales a la gestión editorial, de cualquier revista independiente de su enfoque, como lo son: cumplimiento de periodicidad, tiempos de respuesta, formatos disponibles, idiomas de publicación, costos de publicación y sometimiento, y manejo de licencias de reproducción. Se realizó un análisis de datos cuantitativo de las 2643 revistas latinoamericanas incluidas en DOAJ a noviembre de 2019. Al analizar los datos de las revistas incluidas en este sistema, se encontró desactualización o falta de precisión en los datos reportados que puede perjudicar la reputación de las revistas. Se concluye, entre otros aspectos, que hay evidencias de demoras en los procesos de revisión y ausencia de formatos interoperables que garanticen el adecuado posicionamiento de los artículos a nivel de la web.The objective of the present research study focused on analyzing transversal criteria data for editorial management of scientific journals, regardless of their field, that is provided by the Directory of Open Access Journals (DOAJ). The criteria examined included: response time, formats available, publishing language, publication and reviewing costs, and licensing management. A quantitative analysis was performed analyzing the data of the DOAJ journals resulting in 2643 Latin American journals retrieved. Data analyzes showed that there was outdated information or lack of precision at DOAJ that can harm the reputation of journals. It is concluded, among other aspects, that there was evidence of delays in the review processes and that there was an absence of interoperable formats that are required to ensure the proper positioning of articles on the web.Fil: González-Sanabria, Juan S.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Aparicio, Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro Argentino de Información Científica y Tecnológica; ArgentinaFil: Burgos-Pineda, Diego A.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Guiza-Pinzón, Fabián D.. Universidad de Boyaca; Colombi

Indexing and summary services, an undervalued opportunity to improve the visibility and dissemination of articles published in Latin American scientific journals: DOAJ case

El objetivo de la presente investigación se centró en analizar el conjunto de datos provistos por el Directorio de Revistas de Acceso Abierto (DOAJ, por sus siglas en ingles), respecto a criterios transversales a la gestión editorial, de cualquier revista independiente de su enfoque, como lo son: cumplimiento de periodicidad, tiempos de respuesta, formatos disponibles, idiomas de publicación, costos de publicación y sometimiento, y manejo de licencias de reproducción. Se realizó un análisis de datos cuantitativo de las 2643 revistas latinoamericanas incluidas en DOAJ a noviembre de 2019. Al analizar los datos de las revistas incluidas en este sistema, se encontró desactualización o falta de precisión en los datos reportados que puede perjudicar la reputación de las revistas. Se concluye, entre otros aspectos, que hay evidencias de demoras en los procesos de revisión y ausencia de formatos interoperables que garanticen el adecuado posicionamiento de los artículos a nivel de la web.The objective of the present research study focused on analyzing transversal criteria data for editorial management of scientific journals, regardless of their field, that is provided by the Directory of Open Access Journals (DOAJ). The criteria examined included: response time, formats available, publishing language, publication and reviewing costs, and licensing management. A quantitative analysis was performed analyzing the data of the DOAJ journals resulting in 2643 Latin American journals retrieved. Data analyzes showed that there was outdated information or lack of precision at DOAJ that can harm the reputation of journals. It is concluded, among other aspects, that there was evidence of delays in the review processes and that there was an absence of interoperable formats that are required to ensure the proper positioning of articles on the web.Fil: González-Sanabria, Juan S.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Aparicio, Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro Argentino de Información Científica y Tecnológica; ArgentinaFil: Burgos-Pineda, Diego A.. Universidad Pedagógica y Tecnológica de Colombia; ColombiaFil: Guiza-Pinzón, Fabián D.. Universidad de Boyaca; Colombi

Collagen-Mimetic Hydrogels Promote Human Endothelial Cell Adhesion, Migration and Phenotypic Maturation

This work evaluates the response of human aortic endothelial cells (HAECs) to thromboresistant collagen-mimetic hydrogel coatings toward improving the biocompatibility of existing off-the-shelf small-caliber vascular grafts. Specifically, bioactive hydrogels-previously shown to support α1/α2 integrin-mediated cell adhesion but to resist platelet activation-were fabricated by combining poly(ethylene glycol) (PEG) with a 120 kDa, triple-helical collagen-mimetic protein (Scl2-2) containing the GFPGER adhesion sequence. Analysis of HAECs seeded onto the resulting PEG-Scl2-2 hydrogels demonstrated that HAEC adhesion increased with increasing Scl2-2 concentration, while HAEC migration rate decreased over this same concentration range. In addition, evaluation of HAEC phenotype at confluence indicated significant differences in the gene expression of NOS3, thrombomodulin, and E-selectin on the PEG-Scl2-2 hydrogels relative to PEG-collagen controls. At the protein level, however, only NOS3 was significantly different between the PEG-Scl2-2 and PEG-collagen surfaces. Furthermore, PECAM-1 and VE-cadherin expression on PEG-Scl2-2 hydrogels versus PEG-collagen controls could not be distinguished at either the gene or protein level. Cumulatively, these data indicate the PEG-Scl2-2 hydrogels warrant further investigation as off-the-shelf graft coatings. In future studies, the Scl2-2 protein can potentially be modified to include additional extracellular matrix or cytokine binding sites to further improve endothelial cell responses

Removal of cationic pollutants from water by xanthated corn cob: optimization, kinetics, thermodynamics, and prediction of purification process

The removal of Cr(III) ions and methylene blue (MB) from aqueous solutions by xanthated corn cob (xCC) in batch conditions was investigated. The sorption capacity of xCC strongly depended of the pH, and increase when the pH rises. The kinetics was well fitted by pseudo-second order and Chrastil’s model. Sorption of Cr(III) ions and MB on xCC was rapid during the first 20 min of contact time and, thereafter, the biosorption rate decrease gradually until reaching equilibrium. The maximum sorption capacity of 17.13 and 83.89 mg g-1 for Cr(III) ions and MB, respectively was obtained at 40 °C, pH 5 and sorbent dose 4 g dm-3 for removal of Cr(III) ions and 1 g dm-3 for removal of MB. The prediction of purification process was successfully carried out and the verification of theoretically calculated amounts of sorbent was confirmed by using packed-bed column laboratory system with recirculation of the aqueous phase. The wastewater from chrome plating industry was successfully purified, i.e. after 40 min concentration of Cr(III) ions was decreased lower than 0.1 mg dm-3. Also, removal of MB from the river water was successfully carried out and after 40 min removal efficiency was about 94 %

Expanding the diversity of mycobacteriophages: Insights into genome architecture and evolution

Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists. © 2011 Hatfull et al

The influence of non-carious lesions in the surgical treatment of gingival recession: A systematic review & meta-analysis

Background: The presence of a non-carious cervical lesion (NCCL) is a complicating factor for tooth coverage following gingival recession. It is generally associated with disappearance of the enamel-cementum junction, a key landmark, and a surface discrepancy requiring restoration or compensation using a connective tissue graft (CTG). The aim of this systematic review is to study the efficacy of periodontal plastic surgery on recession defects associated with a NCCL, with or without restorative treatment. Materials and methods: RCT assessing the root coverage of teeth with Miller's class I and class II isolated gingival recession with an NCCL published up to April 2020, with at least 10 patients per group and a follow-up longer than 6 months, were included through electronic databases and hand-searched journals. Results: Seven articles were finally included. Treatment systematically consisted of a coronally advanced flap in association with partial or complete restorative treatment ± CTG. Meta-analyses showed that periodontal plastic procedures are less effective in terms of complete root coverage in cases of teeth with an NCCL. Overall Mean Recession Reduction was 2.00 mm (CI: [1.72, 2.28]), and overall mean complete root coverage was 5% (CI: [2, 8]). Conclusion: The presence of an NCCL is a complicating factor in plastic surgery. The use of CTG without NCCL restoration provides better outcomes except for the reduction of dental hypersensitivity for which the combined treatment (restoration + CTG) is the most effective

Adsorption of Basic Dyes onto Natural Clay

The adsorption ability of natural clay towards the removal of basic dyes from aqueous textile solutions was investigated. The equilibrium isotherms were measured and analyzed using the Langmuir model and the experimental results compared with the theoretical data. The adsorbent exhibited considerable adsorption capacities of 567, 526, 427 and 300 mg/g towards Neutral Red, Methyl Violet, Methyl Green and Methylene Blue, respectively. Thus, the clay may be used as a cost-effective industrial adsorbent for the removal of basic dyes from industrial effluents