Papers by Juan David Fuentes Palma
The American Surgeon
Neutrophil adhesion and recruitment represents one of the early cellular events that occur during... more Neutrophil adhesion and recruitment represents one of the early cellular events that occur during hepatic ischemia/reperfusion (IR) injury and plays a critical role in determining the extent of tissue damage. The adhesion molecules, such as selectins and intercellular adhesion molecules (ICAM), are important in mediating neutrophil-endothelial cell interactions and neutrophil emigration. The goal of this study was to evaluate the role of P-selectin and ICAM-1 in hepatic IR injury. Male wild-type and P-selectin/ICAM-1-deficient (P/I null) mice underwent 90 minutes of partial hepatic ischemia followed by reperfusion at various time points (0, 1.5, 3, and 6 hours). Reperfusion caused a time-dependent hepatocellular injury in both wild-type and P/I null mice as judged by plasma alanine aminotransferase (ALT) levels and liver histopathology examination. Although ALT levels were slightly lower in the P/I null mice compared with the wild-type mice the differences were not statistically sig...
La geografía como objeto social de estudio, reviste unas características clave para su interpreta... more La geografía como objeto social de estudio, reviste unas características clave para su interpretación, en primera instancia debe comprenderse como estudio del "espacio geográfico", el cual es una conjunción entre espacio físico territorial y su concepción abstracta, es decir unos objetos geográficos dispuestos en un espacio físico y su concepción dinámica. En segunda instancia, comprenderlo, como "construcción social" es un hecho indisoluble, puesto que se produce con la misma sociedad, la cual puede ser concebida como la vida que lo anima y lo lleva a "ser".
A Dios por el tiempo que le corresponde a su servicio. Al Padre José Cifuentes por su valiosa guí... more A Dios por el tiempo que le corresponde a su servicio. Al Padre José Cifuentes por su valiosa guía a través del difícil sendero de la investigación.
Rev Asoc Med Argent, 1996
Revista General De Marina, 2011
Clarín: Revista de Nueva Literatura, 1997
Biblioteca de la Universidad Complutense de Madrid, Base de datos de artículos de revistas, ...
Clarín: Revista de nueva literatura, 1997
... José Manuel Benítez Ariza: La grandeza de lo sencillo. Autores: Juan Carlos Palma; Localizaci... more ... José Manuel Benítez Ariza: La grandeza de lo sencillo. Autores: Juan Carlos Palma; Localización: Clarín: Revista de nueva literatura, ISSN 1136-1182, Año nº 2, Nº 7, 1997 , págs. 23-27. Fundación Dialnet. Acceso de usuarios registrados. ...
Clarín: Revista de Nueva Literatura, 1998
Biblioteca de la Universidad Complutense de Madrid, Base de datos de artículos de revistas, ...
Nanotechnology, 2008
Magnetic properties of arrays of nanowires produced inside the pores of anodic alumina membranes ... more Magnetic properties of arrays of nanowires produced inside the pores of anodic alumina membranes have been studied by means of vibrating sample magnetometer techniques. In these systems the length of the wires strongly influences the coercivity of the array. A simple model for the coercivity as a function of the geometry is presented which exhibits good agreement with experimental results. Magnetostatic interactions between the wires are responsible for a decrease of the coercive field.
Materials Letters, 2013
Single crystalline hexagonal cobalt nanoplates with diameter ca. 260 nm and thicknesses of 10 nm ... more Single crystalline hexagonal cobalt nanoplates with diameter ca. 260 nm and thicknesses of 10 nm were synthesized through a one step simple reduction process using a soft-template approach. The sample exhibits a ferromagnetic behavior with a high coercivity field. The effect of the shape anisotropy on magnetic properties was investigated using numerical simulations, showing good agreement with experimental results.
Journal of Surgical Research, 2001
Background. Cytokine production is a critical component of ischemia/reperfusion (IR) injury. In t... more Background. Cytokine production is a critical component of ischemia/reperfusion (IR) injury. In the liver, Kupffer cells produce cytokines and chemokines (i.e., cytokines with chemoattractant properties) that are important mediators in neutrophil recruitment and subsequent hepatocellular injury. Therefore, the role of Kupffer cells in chemokine production in hepatic IR injury was investigated. Methods. Adult male C57BL/6 mice underwent 90 min of partial hepatic ischemia followed by various reperfusion times (i.e., 0, 1. and h). Gadolinium chloride (GC), which inhibits Kupffer cell activity, was administered to mice 48 and 24 h prior to ischemia. The control group received a corresponding volume of normal saline. Plasma levels of the cytokine macrophage inflammatory protein-2 (MIP-2), KC, and tumor necrosis factor (TNF)-␣ and liver mRNA were measured. Liver injury was assessed by plasma level of alanine transaminase (ALT) and histopathology. Results. A reperfusion time-dependent liver injury occurred as indicated by increased levels of plasma ALT and histopathology. The injury was associated with increased plasma TNF-␣, MIP-2, and KC and their hepatic mRNA expression and neutrophil infiltration into ischemic lobes of the liver. GC treatment significantly reduced the number of Kupffer cells as determined by the immunostained liver tissue sections. The extent of liver injury significantly decreased in GCtreated mice that were associated with decreased levels of plasma ALT, TNF-␣, MIP-2, and KC and neutrophil infiltration. Conclusions. This study suggests that Kupffer cells are major contributors to cytokine production in hepatic IR and their modulation may serve as a potential target for therapeutic intervention.
Journal of Nanoscience and Nanotechnology, 2009
This paper examines the influence of electrodeposition potential, pore size, pH, composition, and... more This paper examines the influence of electrodeposition potential, pore size, pH, composition, and temperature of the electrolytic bath on the structure of nickel nanowires arrays electrodeposited into anodic alumina oxide porous membranes. Scanning electron microscopy, X-ray diffraction, and transmission electron microscopy analysis were employed to characterize the structural and morphological properties of the nanowires. Results show that the electrodeposition potential controls the growth of nickel nanowires along some preferential crystallographic planes. At -0.90 V (vs. Ag/AgCl) single crystalline nanowires with a strong (111) orientation were obtained. High temperatures and a moderately acid pH solution contributed to improve the single crystalline character of nanowires. The presence of chloride ions produced polycrystalline nanowires at low temperature and single crystalline nanowires at high temperature. The influence of the electrodeposition potential in their magnetic anisotropies is also reported.
Journal of Magnetism and Magnetic Materials, 2012
During the last decade several methods to control the vortex chirality in nanodots have been prop... more During the last decade several methods to control the vortex chirality in nanodots have been proposed. One of them, the introduction of asymmetry in the geometry of the dots, originates interesting effects on the magnetic behavior of the particle. However, asymmetry in core-free structures is also interesting to investigate because of the reproducibility of their magnetic properties. In this work
cybertesis.cl
El Desarrollo de la Lectura Melódica a Través del Sistema de Grados Tonales. - Juan Sebastián Ver... more El Desarrollo de la Lectura Melódica a Través del Sistema de Grados Tonales. - Juan Sebastián Vergara Palma.
geotecniaambiental.cl
Chilean companies that intend to develop projects that may affect the environment should submit t... more Chilean companies that intend to develop projects that may affect the environment should submit the activities of the project life-cycle and the measures for mitigation, compensation or reclamation of these environmental impacts to an evaluation process, in which the competent authority verifies its environmental feasibility. This process starts with the submission of an environmental impact statement or an environmental impact study (EIS). In this context of social and environmental responsibility, some companies decide to make voluntary environmental commitments as members of the community where the project or activity is taking place, with the purpose of contributing to the solution of a problem that although has not yet arisen from the performance of the project, may affect them in the future. This article reports the experience of voluntary environmental commitments, proposed within the framework of the EIS by a private company as an effective management tool to submit appropriate technical solutions to improve the solid waste management in a Commune in the north of Chile. To address the problem of the final disposal of solid wastes generated by the Caldera commune, it was necessary to collect available information, generate technical data and hold periodical meetings with different public and private entities, which led to the proposal of a technical solution through an engineering project that can be submitted to public or private financial agents. After completion of the work, it was concluded that the voluntary environmental commitments intended to benefit the community are a feasible tool to face environmental problems. This instrument provides a basis for cooperation and association in which commitments are made by public and private entities involved.
Scientific Reports
The original version of this Article contained an error in the Results and analysis section, unde... more The original version of this Article contained an error in the Results and analysis section, under the subheading 'Dynamic magnetic properties' , where the unitary vector " n " did not display correctly.
Mathematics
In this research, we address the problem of evaluating physical stability (PS) to close tailings ... more In this research, we address the problem of evaluating physical stability (PS) to close tailings dams (TD) from medium-sized Chilean mining using artificial intelligence (AI) algorithms. The PS can be analyzed through the study of critical variables of the TD that allow estimating different potential failure mechanisms (PFM): seismic liquefaction, slope instability, static liquefaction, overtopping, and piping, which may occur in this type of tailings storage facilities in a seismically active country such as Chile. Thus, this article proposes the use of four machine learning algorithms, namely random forest (RF), support vector machine (SVM), artificial neural networks (ANN), and extreme gradient boosting (XGBoost), to estimate five possible PFM. In addition, due to the scarcity of data to train the algorithms, the use of generative adversarial networks (GAN) is proposed to create synthetic data and increase the database used. Therefore, the novelty of this article consists in esti...
Minerals
Sand tailings dams have historically been the most commonly used technology for tailings storage ... more Sand tailings dams have historically been the most commonly used technology for tailings storage in Chile. Although engineering advances have resulted in the construction of approximately 250-m-high facilities, some operational challenges still remain, including compaction control. Control is currently performed at a few control points in a dam embankment, without considering a series of factors that affect its mechanical behavior (e.g.,layer thickness and material variability). Within this context, geostatistics can be applied in combination with low-cost geotechnical tools as an alternative to improve compaction control in tailings storage facilities. In this study, an extensive field investigation was carried out. A total of 91 PANDA penetrometer tests were conducted to monitor the degree of compaction in an experimental classified sand tailings dam. The results were analyzed using stochastic interpolation for ordinary kriging and considering the spatial distribution of the cone ...
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Papers by Juan David Fuentes Palma