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11
result(s) for
"Valdebenito, Cristián"
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Superparamagnetic energetic nanoparticles: a surface self-propagation pathway for the thermal decomposition of ammonium perchlorate
by
Valenzuela, Fernando
,
Gaete, José
,
Valdebenito, Cristián
in
Activation energy
,
Ammonium perchlorates
,
Analysis
2023
In this work, our research group developed usable low-cost superparamagnetic nanoparticles (Fe
3
O
4
@NTA) that behave as an excellent energetic material to accelerate the thermal decomposition of ammonium perchlorate (AP). As a synthetic strategy, magnetite nanoparticles (Fe
3
O
4
) were coated with nitrilotriacetic acid (NTA) by a simple preparation method. Based on High-resolution transmission electron microscopy (HR-TEM) and vibrating sample magnetometer (VSM) results, Fe
3
O
4
@NTA presents a mean diameter of 7.4 nm and superparamagnetic behavior. Chemical characterization by Energy-dispersive X-ray spectroscopy (XPS), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) provided enough evidence for the presence of a carboxylic acid group and magnetite in the sample. The Fe
3
O
4
@NTA catalyst diminishes AP high-temperature decomposition (HTD) to 342 °C and shows a low activation energy (98.02 kJ mol
−1
). In addition, after the burning rate test, it was observed that these resulting nanoparticles showed an adequate magnetic response against an external magnet. These results are promising for future research, as the opportunity opens to reuse this functional magnetic material in successive catalytic cycles, thus contributing soon to the recycling of raw materials necessary for interplanetary travel.
Graphical abstract
Journal Article
Alkylated Benzodithienoquinolizinium Salts as Possible Non-Fullerene Organic N-Type Semiconductors: An Experimental and Theoretical Study
by
Valdebenito, Cristian
,
Aracena, Andrés
,
Celis, Freddy
in
Alkylation
,
Current carriers
,
Dimers
2021
Three photobicyclized benzodithienoquinolizinium tetrafluoroborates (BPDTQBF4) were prepared and evaluated by UV–Vis and fluorescence spectral, electrochemical analysis, and by theoretical calculations as possible organic n-type semiconductors. Evaluation and comparison of their LUMO levels, HOMO-LUMO energy gaps as monomeric and π-stacked dimers with those of other materials, suggest their potential as organic n-type semiconductors. Calculations of their relative charge carrier mobilities confirmed this potential for one derivative with a long (C-14) alkyl chain appended to the polycyclic planar π-system.
Journal Article
Identification, Quantification, and Characterization of HIV-1 Reservoirs in the Human Brain
by
D’Amico, Daniela
,
Valdebenito, Silvana
,
Eugenin, Eliseo A.
in
Accuracy
,
Acquired immune deficiency syndrome
,
AIDS
2022
The major barrier to cure HIV infection is the early generation and extended survival of HIV reservoirs in the circulation and tissues. Currently, the techniques used to detect and quantify HIV reservoirs are mostly based on blood-based assays; however, it has become evident that viral reservoirs remain in tissues. Our study describes a novel multi-component imaging method (HIV DNA, mRNA, and viral proteins in the same assay) to identify, quantify, and characterize viral reservoirs in tissues and blood products obtained from HIV-infected individuals even when systemic replication is undetectable. In the human brains of HIV-infected individuals under ART, we identified that microglia/macrophages and a small population of astrocytes are the main cells with integrated HIV DNA. Only half of the cells with integrated HIV DNA expressed viral mRNA, and one-third expressed viral proteins. Surprisingly, we identified residual HIV-p24, gp120, nef, vpr, and tat protein expression and accumulation in uninfected cells around HIV-infected cells suggesting local synthesis, secretion, and bystander uptake. In conclusion, our data show that ART reduces the size of the brain’s HIV reservoirs; however, local/chronic viral protein secretion still occurs, indicating that the brain is still a major anatomical target to cure HIV infection.
Journal Article
Copper-Polyurethane Composite Materials: Particle Size Effect on the Physical-Chemical and Antibacterial Properties
2020
In this work, thermoplastic polyurethane (TPU) composites incorporated with 1.0 wt% Cu particles were synthesized by the melt blending method. The effect of the incorporated copper particle size on the antibacterial, thermal, rheological, and mechanical properties of TPU was investigated. The obtained results showed that (i) the addition of copper particles increased the thermal and mechanical properties because they acted as co-stabilizers of polyurethane (PU) (ii) copper nanoparticles decreased the viscosity of composite melts, and (iii) microparticles > 0.5 µm had a tendency to easily increase the maximum torque and formation of agglomerates. SEM micrographics showed that a good mixture between TPU and copper particles was obtained by the extrusion process. Additionally, copper-TPU composite materials effectively inhibited the growth of the Gram-negative Escherichia coli and the Gram-positive Staphylococcus aureus. Considering that the natural concentration of copper in the blood is in the range of 0.7–0.12 mg/L and that the total migration value of copper particles from TPU was 1000 times lower, the results suggested that TPU nanocomposites could be adequately employed for biomedical applications without a risk of contamination.
Journal Article
Evaluación y comparación de la eficiencia de dos sistemas de incubación de huevos de Genypterus chilensis (Guichenot, 1848) Evaluation and comparison of the efficiency of two incubation systems for Genypterus chilensis (Guichenot, 1848) eggs
2012
Actualmente la tendencia de la acuicultura mundial está orientada hacia la diversificación de los cultivos, principalmente de especies nativas. El congrio colorado Genypterus chilensis es un pez nativo de alta demanda gastronómica y explotación estacional que lo proyecta como candidato para el desarrollo de su tecnología de cultivo. El objetivo de este trabajo fue evaluar la eficiencia de dos sistemas de incubación de masas de huevos de G. chilensis, uno con circuito cerrado de agua (SICC) y el otro con circuito abierto (SICA); su eficiencia fue medida por el porcentaje de eclosión de huevos. Dos ensayos fueron realizados midiendo y comparando los porcentajes de fecundación y eclosión de huevos en cuatro réplicas entre los dos sistemas, encontrándose solo diferencias significativas entre los porcentajes de fecundación del bioensayo 2. El bioensayo 1 tuvo un 81% promedio de fecundación de los huevos y el porcentaje promedio de eclosión para el SICC fue 42,9 ± 34,5% y para el SICA fue 0,0 ± 0,0%. El bioensayo 2 tuvo un porcentaje promedio de fecundación de los huevos de 87,3 ± 2,6% para el SICC y 79,8 ± 3,2% para el SICA y el porcentaje promedio de eclosión para el SICC fue 27,9 ± 33,7% y para el SICA fue 4,8 ± 5,6%. Se discuten los parámetros de incubación para obtener una máxima eclosión y se entrega una proposición para mejorar el sistema SICC. El sistema de incubación con circuito cerrado de agua generó mayores sobrevivencias en los huevos de G. chilensis.The current trend in world aquaculture is towards the diversification of cultures, mainly native species. The red cusk eel Genypterus chilensis is a native Chilean species of high gastronomic demand and seasonal exploitation that is projected as a candidate for the development of farming technology. The objective of this study was to test the efficiency of two incubation systems for G. chilensis egg masses, one with a closed water circuit (SICC) and the other with an open water circuit (SICA). Efficiency was measured by the percentage of eggs hatched. Two assays were performed, measuring and comparing the percentages of egg fecundation and hatching in four replicates between the two incubation systems. Significant differences were only found between the percentages of fecundation of bioassay 2. On average, in bioassay 1, egg fecundation reached 81%, and the average of hatching for the SICC was 42.9 ± 34.5% and for the SICA was 0.0 ± 0.0%. Bioassay 2 had an average fecundation of 87.3 ± 2.6% for the SICC and 79.8 ± 3.2% for the SICA, and the average for hatching was 27.9 ± 33.7% for the SICC and 4.8 ± 5.6% for the SICA. Incubation parameters for maximum hatching were discussed and a proposal was made for improving the SICC system. The incubation system with a closed water circuit generated greater survival of G. chilensis eggs.
Journal Article
Evaluation and comparison of the efficiency of two incubation systems for Genypterus chilensis
2012
The current trend in world aquaculture is towards the diversification of cultures, mainly native species. The red cusk eel Genypterus chilensis is a native Chilean species of high gastronomic demand and seasonal exploitation that is projected as a candidate for the development of farming technology. The objective of this study was to test the efficiency of two incubation systems for G. chilensis egg masses, one with a closed water circuit (SICC) and the other with an open water circuit (SICA). Efficiency was measured by the percentage of eggs hatched. Two assays were performed, measuring and comparing the percentages of egg fecundation and hatching in four replicates between the two incubation systems. Significant differences were only found between the percentages of fecundation of bioassay 2. On average, in bioassay 1, egg fecundation reached 81%, and the average of hatching for the SICC was 42.9 [+ or -] 34.5% and for the SICA was 0.0 [+ or -] 0.0%. Bioassay 2 had an average fecundation of 87.3 [+ or -] 2.6% for the SICC and 79.8 [+ or -] 3.2% for the SICA, and the average for hatching was 27.9 [+ or -] 33.7% for the SICC and 4.8 [+ or -] 5.6% for the SICA. Incubation parameters for maximum hatching were discussed and a proposal was made for improving the SICC system. The incubation system with a closed water circuit generated greater survival of G. chilensis eggs. Keywords: incubation, eggs, red cusk eel, Genypterus chilensis, Chile. Actualmente la tendencia de la acuicultura mundial esta orientada hacia la diversificacion de los cultivos, principalmente de especies nativas. El congrio colorado Genypterus chilensis es un pez nativo de alta demanda gastronomica y explotacion estacional que lo proyecta como candidato para el desarrollo de su tecnologia de cultivo. El objetivo de este trabajo fue evaluar la eficiencia de dos sistemas de incubacion de masas de huevos de G. chilensis, uno con circuito cerrado de agua (SICC) y el otro con circuito abierto (SICA); su eficiencia fue medida por el porcentaje de eclosion de huevos. Dos ensayos fueron realizados midiendo y comparando los porcentajes de fecundacion y eclosion de huevos en cuatro replicas entre los dos sistemas, encontrandose solo diferencias significativas entre los porcentajes de fecundacion del bioensayo 2. El bioensayo 1 tuvo un 81% promedio de fecundacion de los huevos y el porcentaje promedio de eclosion para el SICC fue 42,9 [+ o -] 34,5% y para el SICA fue 0,0 [+ o -] 0,0%. El bioensayo 2 tuvo un porcentaje promedio de fecundacion de los huevos de 87,3 [+ o -] 2,6% para el SICC y 79,8 [+ o -] 3,2% para el SICA y el porcentaje promedio de eclosion para el SICC fue 27,9 [+ o -] 33,7% y para el SICA fue 4,8 [+ o -] 5,6%. Se discuten los parametros de incubacion para obtener una maxima eclosion y se entrega una proposicion para mejorar el sistema SICC. El sistema de incubacion con circuito cerrado de agua genero mayores sobrevivencias en los huevos de G. chilensis. Palabras clave: incubacion, huevos, congrio colorado, Genypterus chilensis, Chile.
Journal Article
Evaluación y comparación de la eficiencia de dos sistemas de incubación de huevos de Genypterus chilensis (Guichenot, 1848)
by
Alfaro, Denis
,
Ramírez, Diego
,
Pichara, Cristian
in
FISHERIES
,
MARINE & FRESHWATER BIOLOGY
,
OCEANOGRAPHY
2012
Actualmente la tendencia de la acuicultura mundial está orientada hacia la diversificación de los cultivos, principalmente de especies nativas. El congrio colorado Genypterus chilensis es un pez nativo de alta demanda gastronómica y explotación estacional que lo proyecta como candidato para el desarrollo de su tecnología de cultivo. El objetivo de este trabajo fue evaluar la eficiencia de dos sistemas de incubación de masas de huevos de G. chilensis, uno con circuito cerrado de agua (SICC) y el otro con circuito abierto (SICA); su eficiencia fue medida por el porcentaje de eclosión de huevos. Dos ensayos fueron realizados midiendo y comparando los porcentajes de fecundación y eclosión de huevos en cuatro réplicas entre los dos sistemas, encontrándose solo diferencias significativas entre los porcentajes de fecundación del bioensayo 2. El bioensayo 1 tuvo un 81% promedio de fecundación de los huevos y el porcentaje promedio de eclosión para el SICC fue 42,9 ± 34,5% y para el SICA fue 0,0 ± 0,0%. El bioensayo 2 tuvo un porcentaje promedio de fecundación de los huevos de 87,3 ± 2,6% para el SICC y 79,8 ± 3,2% para el SICA y el porcentaje promedio de eclosión para el SICC fue 27,9 ± 33,7% y para el SICA fue 4,8 ± 5,6%. Se discuten los parámetros de incubación para obtener una máxima eclosión y se entrega una proposición para mejorar el sistema SICC. El sistema de incubación con circuito cerrado de agua generó mayores sobrevivencias en los huevos de G. chilensis.
Journal Article
Evaluation and comparison of the efficiency of two incubation systems for Genypterus chilensis
2012
The current trend in world aquaculture is towards the diversification of cultures, mainly native species. The red cusk eel Genypterus chilensis is a native Chilean species of high gastronomic demand and seasonal exploitation that is projected as a candidate for the development of farming technology. The objective of this study was to test the efficiency of two incubation systems for G. chilensis egg masses, one with a closed water circuit (SICC) and the other with an open water circuit (SICA). Efficiency was measured by the percentage of eggs hatched. Two assays were performed, measuring and comparing the percentages of egg fecundation and hatching in four replicates between the two incubation systems. Significant differences were only found between the percentages of fecundation of bioassay 2. On average, in bioassay 1, egg fecundation reached 81%, and the average of hatching for the SICC was 42.9 [+ or -] 34.5% and for the SICA was 0.0 [+ or -] 0.0%. Bioassay 2 had an average fecundation of 87.3 [+ or -] 2.6% for the SICC and 79.8 [+ or -] 3.2% for the SICA, and the average for hatching was 27.9 [+ or -] 33.7% for the SICC and 4.8 [+ or -] 5.6% for the SICA. Incubation parameters for maximum hatching were discussed and a proposal was made for improving the SICC system. The incubation system with a closed water circuit generated greater survival of G. chilensis eggs.
Journal Article
Evaluation and comparison of the efficiency of two incubation systems for Genypterus chilensis (Guichenot, 1848) eggs/Evaluación y comparación de la eficiencia de dos sistemas de incubación de huevos de Genypterus chilensis (Guichenot, 1848)
2012
The current trend in world aquaculture is towards the diversification of cultures, mainly native species. The red cusk eel Genypterus chilensis is a native Chilean species of high gastronomic demand and seasonal exploitation that is projected as a candidate for the development of farming technology. The objective of this study was to test the efficiency of two incubation systems for G. chilensis egg masses, one with a closed water circuit (SICC) and the other with an open water circuit (SICA). Efficiency was measured by the percentage of eggs hatched. Two assays were performed, measuring and comparing the percentages of egg fecundation and hatching in four replicates between the two incubation systems. Significant differences were only found between the percentages of fecundation of bioassay 2. On average, in bioassay 1, egg fecundation reached 81%, and the average of hatching for the SICC was 42.9 [+ or -] 34.5% and for the SICA was 0.0 [+ or -] 0.0%. Bioassay 2 had an average fecundation of 87.3 [+ or -] 2.6% for the SICC and 79.8 [+ or -] 3.2% for the SICA, and the average for hatching was 27.9 [+ or -] 33.7% for the SICC and 4.8 [+ or -] 5.6% for the SICA. Incubation parameters for maximum hatching were discussed and a proposal was made for improving the SICC system. The incubation system with a closed water circuit generated greater survival of G. chilensis eggs.
Journal Article