A real time method for surface cleanliness measurement

The measurement of surface cleanliness is a signifi cant problem in many industrial and technological processes. Existing methods are based on laboratory procedures, that are not performed in real time, can not be automated, and usually are restricted to a small portion of the sample. In this study we describe a new method for real time measurement of the amount of surface dirt or contamination deposited on a surface. It relies on the ablation of the surface dirt film by means of a short laser pulse, and the subsequent measurement of the emitted sound. The intensity of the sound is proportional to the amount of surface dirt and provides a direct measurement of the cleanli ness of the surface. We also developed a reference sample for calibration, based on a uniform distribution of dots printed on white paper. The density and the dot size can be easily modified providing a homogeneous, uniform and reproducible standard for the measurement. Based on this method, we designed, de veloped and patented the first industrial instrument for on line determination of the degree of cleanliness of manufactured cold rolled steel plate bobbins.Facultad de Ciencias Exacta

A real time method for surface cleanliness measurement

The measurement of surface cleanliness is a signifi cant problem in many industrial and technological processes. Existing methods are based on laboratory procedures, that are not performed in real time, can not be automated, and usually are restricted to a small portion of the sample. In this study we describe a new method for real time measurement of the amount of surface dirt or contamination deposited on a surface. It relies on the ablation of the surface dirt film by means of a short laser pulse, and the subsequent measurement of the emitted sound. The intensity of the sound is proportional to the amount of surface dirt and provides a direct measurement of the cleanli ness of the surface. We also developed a reference sample for calibration, based on a uniform distribution of dots printed on white paper. The density and the dot size can be easily modified providing a homogeneous, uniform and reproducible standard for the measurement. Based on this method, we designed, de veloped and patented the first industrial instrument for on line determination of the degree of cleanliness of manufactured cold rolled steel plate bobbins.Facultad de Ciencias Exacta

Development of Antibody-Coated Magnetite Nanoparticles for Biomarker Immobilization

Magnetic nanoparticles (MNPs) have great potential in biomedical applications because of their magnetic response offers the possibility to direct them to specific areas and target biological entities. Magnetic separation of biomolecules is one of the most important applications of MNPs because their versatility in detecting cancer biomarkers. However, the effectiveness of this method depends on many factors, including the type of functionalization onto MNPs. Therefore, in this study, magnetite nanoparticles have been developed in order to separate the 5′-nucleotidase enzyme (5eNT). The 5eNT is used as a bio-indicator for diagnosing diseases such as hepatic ischaemia, liver tumor, and hepatotoxic drugs damage. Magnetic nanoparticles were covered in a core/shell type with silica, aminosilane, and a double shell of silica-aminosilane. A ScFv (fragment antibody) and anti-CD73 antibody were attached to the coated nanoparticles in order to separate the enzyme. The magnetic separation of this enzyme with fragment antibody was found to be 28% higher than anti-CD73 antibody and the enzyme adsorption was improved with the double shell due to the increased length of the polymeric chain. Magnetite nanoparticles with a double shell (silica-aminosilane) were also found to be more sensitive than magnetite with a single shell in the detection of biomarkers

Investigation of laser annealing mechanisms in thin film coatings by photothermal microscopy

We study the evolution of the absorptance of amorphous metal oxide thin films when exposed to intense CW laser radiation measured using a photothermal microscope. The evolution of the absorptance is characterized by a nonexponential decay. Different models that incorporate linear and nonlinear absorption, free carrier absorption, and defect diffusion are used to fit the results, with constraints imposed on the fit parameters to scale with power and intensity. The model that best fits is that two types of interband defects are passivated independently, one by a one-photon process and the other one by a two-photon process.Fil: Zaldivar Escola, Facundo. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mingolo, Nélida. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física; ArgentinaFil: Martínez, Oscar E.. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física; ArgentinaFil: Rocca, Jorge J.. State University of Colorado - Fort Collins; Estados UnidosFil: Menoni, Carmen S.. State University of Colorado - Fort Collins; Estados Unido

Exposure of pineapple shoot tips to liquid nitrogen and cryostorage do not affect the histological status of regenerated plantlets

[EN] Conservation of pineapple (Ananas comosus L. Merr.) genetic resources - including cryopreservation in liquid N-2 at -196 degrees C - is essential for future breeding programmes to develop new varieties with improved agronomic performance. However, the potentially deleterious effects of cryopreservation on subsequent plant regrowth should be evaluated before large-scale development of cryobanks is implemented. This paper describes the histological analysis of pineapple plantlets regenerated from cryopreserved shoot tips. Two controls were included in the study: i) conventional micropropagation-derived plantlets, and ii) plants from shoot tips subjected to pre-cryostorage conditioning treatments but never exposed to liquid N-2. Histological studies of roots, leaves and stems were conducted after 45 days of hardening. No statistically significant differences with the controls were observed in any of the histological parameters evaluated, which supports the practical value of cryopreservation of pineapple germplasm.This research was supported by the Bioplant Centre (Cuba), the Escuela Superior Politecnica Agropecuaria de Manabi Manuel Felix Lopez (Ecuador), the IRD Representation in Benin, and the Universitat Politecnica de Valencia (Spain).Villalobos-Olivera, A.; Nápoles, L.; Mendoza, JR.; Escalante, D.; Martínez, J.; Concepción, O.; Zevallos, BE.... (2019). Exposure of pineapple shoot tips to liquid nitrogen and cryostorage do not affect the histological status of regenerated plantlets. Romanian Biotechnological Letters. 24(6):1061-1066. https://doi.org/10.25083/rbl/24.6/1061.1066S1061106624

Effect of La3+/Sr2+ ordering on the magnetic properties of La2/3Sr1/3MnO3 by first principles calculations

In this work, using DFT + U formalism, we investigate the effect of order-disorder in the A-site occupation byLa3+and Sr2+on the stability of the ferromagnetic order in La2/3Sr1/3MnO3with−Rc3symmetry. To date, adetailed theoretical discussion of such phenomenon, using a combination of different representations of theelectronic structure, is still missing in the Literature. We employed structural models consisting of 120 atomsupercells constructed according to the precise stoichiometry of the compound. Two configurations, describingrandomized and ordered occupation of the La3+/Sr2+ions, were evaluated. We demonstrate that the ferro-magnetic arrangement of La2/3Sr1/3MnO3with randomly distributed La3+and Sr2+ions is more stable. In suchconfiguration wefind that the Mn3+and Mn4+ions are not distinguished, favoring the double-exchange me-chanism, enhanced by the higher degree of covalence in the MneO bonds near the Fermi level between thespin-upMn-egorbitals and the O-porbitals

Controlled Breeding of Coccoloba cowellii Britton (Polygonaceae), a Threatened Endemic Species

Context: Coccoloba cowellii Britton is an endemic plant to Camagüey province, Cuba, which has been reported in critical danger of extinction, though phytochemical studies have revealed the presence of promising compounds with antioxidant activity. Hence, the need for standardizing the potential economic exploitation of the species through preservation has encouraged scholars to study the features of the seeds and germination. Aim: To assess C. cowelli seed dormancy, and evaluate their germination under controlled conditions. Methods: Anatomical and physiological evaluation of C. cowellii seed dormancy. A standard factorial experiment was designed to evaluate the germination capacity under controlled conditions, consisting of three factors, one with two levels, and the other with three levels. All the possible combinations were evaluated, totaling 18 experimental units. Results: The presence of non-dehydration sensitive C. cowellii seeds was checked, along with the absence of factors that can delay their physiological maturity. There were differences in terms of germinative efficiency resulting from scarification as pre-germinative treatments, rather than by inhibition. A significant decrease was observed 180 days following the harvest, while the best results were achieved with the utilization of substrate collected from the natural habitat. Conclusions: C. cowellii seeds can be dehydrated and stored at room temperature to preserve embryo viability of at least 50% of them. The feasibility of germination under controlled conditions favored the implementation of ex-situ controlled steps, the generation of plant material for further research, and the existence of a potential for sustainable production

Reproducción controlada de Coccoloba cowellii Britton (Polygonaceae), una especie endémica amenazada de extinción

Contexto: Coccoloba cowellii Britton es una planta que constituye un endemismo de Camagüey, Cuba, catalogada “En Peligro Crítico” de extinción, pero estudios fitoquímicos han revelado la presencia de compuestos promisorios con actividad antioxidante. La necesidad de compatibilizar la potencial explotación económica de la especie con su conservación, ha llevado a estudiar las particularidades de la semilla y de su germinación. Objetivo: Valorar la dormancia de la semilla de C. cowellii y evaluar su germinación en condiciones controladas. Métodos: Se estudiaron evidencias anatómicas y fisiológicas de la dormancia en simientes de C. cowellii. Para evaluar su capacidad de germinación en condiciones controladas, se diseñó un experimento factorial estándar, que consta de tres factores, de ellos, uno con dos niveles y dos con tres. Se valoraron todas las combinaciones posibles, para un total de 18 unidades experimentales. Resultados: Se comprobó la presencia de semillas no sensibles a la deshidratación en C. cowellii, así como la ausencia de factores que retrasen su madurez fisiológica. Se evidenciaron diferencias en la eficiencia germinativa condicionadas por la escarificación como tratamientos pregerminativos, pero no por la imbibición. Se constató un decrecimiento significativo a partir de los 180 días posteriores a la cosecha y los mejores resultados se obtuvieron utilizando sustrato extraído del hábitat natural. Conclusiones: Es posible deshidratar las semillas de C. cowellii, almacenarlas a temperatura ambiente y conservar la viabilidad del embrión en al menos un 50 % de ellas. La factibilidad de su germinación en condiciones controladas favorece la implementación de medidas de conservación “ex situ”, la obtención de material vegetal para la continuidad de las investigaciones y devela potencialidades para su explotación sostenible

Chalcopyrite Leaching Kinetics in the Presence of Methanol

The dissolution of chalcopyrite under near ambient conditions represents one of the main challenges in the copper industry. Thus, various routes have been proposed for chalcopyrite treatment, such as the use of polar organic solvents, and this has shown promising results. In this paper, we present a study of copper leaching from a chalcopyrite concentrate in aqueous acidic medium with methanol and various H2O2 concentrations at 15, 30, and 40 °C. The results show that nearly complete copper extraction was attained within 5 h at 40 °C. The extraction percentages were plotted as functions of time at each temperature. The experimental data were modeled using the shrinking core model considering the cylindrical particle shape (shrinking cylinder model) within acceptable confidence levels, yielding an estimated activation energy of 24.3 kJ/mol. Furthermore, the process was dependent on the H2O2 concentration, and it acts as a reagent rather than an oxidant in the leaching reaction. It was found that sulfur is the only species present in the solid phase formed during the leaching of chalcopyrite, demonstrating the co-dissolution of both copper and iron