Research Interests:
Research Interests:
Research Interests:
TiO2 nanotubular structures were fabricated on Ti polished and unpolished foils exposed to H2O-Glycerol (50-50Vol.%)+0.27 M NH4F at 20V. The obtained TiO2 nanostructures were analyzed by SEM obtaining the morphological characterization,... more
TiO2 nanotubular structures were fabricated on Ti polished and unpolished foils exposed to H2O-Glycerol (50-50Vol.%)+0.27 M NH4F at 20V. The obtained TiO2 nanostructures were analyzed by SEM obtaining the morphological characterization, from which the roughness factors were calculated. Crystalline phases of both TiO2 nanotubular films were obtained by XRD after annealing at 450 °C and 600 °C for 2 h. The electrochemical stability of the TiO2 nanotubular films was obtained from the potentiodynamic polarization curves (PC) and the linear polarization resistance (Lpr) techniques, exposing the samples in 1M Na2SO4 + H2SO4 solution (pH = 3.2), such pH is in accordance with the acidic wastewater containing sulfur compounds coming from the industries or acid waters of the aquifers, which have been contaminated from the volcanoes nearby. It was concluded that the electrochemical stability of the crystallized nanotubular films is improved with the increase of the annealing temperature of the...
Research Interests:
TiO2 nanotubular structures were formed on titanium foils through anodic oxidation using an electrolyte of Ethyleneglycol-H2O (97:3 Vol %)+0.25 M NH4F at a constant voltage of 60V. The anodized samples were analyzed in a FE-SEM obtaining... more
TiO2 nanotubular structures were formed on titanium foils through anodic oxidation using an electrolyte of Ethyleneglycol-H2O (97:3 Vol %)+0.25 M NH4F at a constant voltage of 60V. The anodized samples were analyzed in a FE-SEM obtaining the geometric parameters of the nanotubular arrays. The diameter and the length of the nanotubes were 112 nm and 65µm |respectively, whereas the wall thickness was 44 nm. Crystalline phase of TiO2 nanotubular films (TNTF) were determined by XRD after annealing at 500°C for 2 h, resulting high intensity peaks of anatase and low intensity peaks of rutile. Then, the crystallized samples were characterized from an optical, photoelectrochemical and photocatalytic point of view. The photoelectrochemical measurements were carried out in 0.5 M Na2SO4 solution using an 8 W UV lamp at a λ= 365 nm, which results were recorded at 0 bias during 10 min under darkness and illumination intervals of 1 min each. Photocatalytic performance of the TNTF was explored wit...
Research Interests:
The array of the TiO2 nanotubular films, also called one-dimensional nanostructures is carried out by electrochemical anodization tests, for which, titanium sheets were used with a high purity (99.7% and 0.25 mm thickness) in a solution... more
The array of the TiO2 nanotubular films, also called one-dimensional nanostructures is carried out by electrochemical anodization tests, for which, titanium sheets were used with a high purity (99.7% and 0.25 mm thickness) in a solution of deionized water and glycerol (50:50 vol.%) + 0.27M NH4F applying a voltage of 20V. Electrochemical tests were performed at an anodization time of 2:30 hours and 3:30 hours. For the tests mirror polished foils and unpolished foils with flat surfaces to achieve better uniform arrays during the anodic growth of nanotubes were used. After anodizing, samples were observed in the scanning electron microscope (SEM) to determine the geometry and morphology of the films. Also, potentiodynamic polarization curves were performed for samples crystallized at 600 °C and 450 °C (polished and unpolished) to determine the electrochemical stability of the films, which were presented at two aqueous solutions: 1M of Na2SO4 (pH= 6.7) and 1M Na2SO4 + H2SO4 (pH= 3.2). M...
Research Interests:
The synthesis of TiO2nanotubular arrays obtained through anodization of Ti foils in ethylene glycol (3% volume DI H2O + 0.25 wt.% NH4F) at high voltage is reported. The physical, chemical, electrochemical, and mechanical characterization... more
The synthesis of TiO2nanotubular arrays obtained through anodization of Ti foils in ethylene glycol (3% volume DI H2O + 0.25 wt.% NH4F) at high voltage is reported. The physical, chemical, electrochemical, and mechanical characterization was made to the TiO2nanotubular arrays. The morphological characterization showed a cylindrical geometry (112 nm inner diameter and 65 μm length), determining a rugosity factor of 1840 points. The electrochemical characterization was carried out exposing four samples: Ti, TiO2amorphous, and two crystalline TiO2nanotubular arrays (450 and 600°C) in two aqueous solutions of different pH: 1 M Na2SO4and 1 M Na2SO4+ H2SO4, using the potentiodynamic polarization curves. The mechanical characterization was performed through the nanoindentation technique applying three different loads (2.5, 5.0, and 10 mN) on the amorphous and the two crystalline TiO2nanotubular samples, obtaining the mechanical parameters such as the hardness, the elastic module, and the m...
Research Interests:
Research Interests:
ABSTRACT
We report a new method based on the ratio of the optical transmittance to monitoring processes of corrosion in stainless steel 304L immersed in a aqueous solution of lithium bromide at 50% wt, at 70°C. The change of the optical... more
We report a new method based on the ratio of the optical transmittance to monitoring processes of corrosion in stainless steel 304L immersed in a aqueous solution of lithium bromide at 50% wt, at 70°C. The change of the optical transmittance that is measured in the solution contaminated, is related to the physical degradation of the samples of stainless steel.
Research Interests:
It was performed a study to determine the corrosion resistance of SS-304 stainless steel exposed to lithium bromide aqueous solution at 50 % (wt.) during a period of 15 days, applying the electrochemical noise technique and the... more
It was performed a study to determine the corrosion resistance of SS-304 stainless steel exposed to lithium bromide aqueous solution at 50 % (wt.) during a period of 15 days, applying the electrochemical noise technique and the polarization curves technique, as well as the conventional weight loss method. The test temperatures were 25, 50, 60, 70 and 80ºC. The main objective was to determine the type of corrosion and corrosion kinetics under the mentioned conditions. The results of the noise signals together with the micrographic observations showed that at 25 and 50ºC the corrosion process was mixed. At 60, 70 and 80ºC the corrosion process was a kind of mixed corrosion, but with a trend to suffer pitting corrosion. A statistical analysis to the current and potential time series was made to obtain the noise resistance Rn, and the Stern-Geary equation and Faraday Law were applied to determine the corrosion rates. In general, it was observed that corrosion rates for SS-304 increased ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
ABSTRACT
Research Interests:
Research Interests:
Research Interests:
Research Interests:
The cystic ectasia of the rete testis is a benign entity with a typical ultrasound appearance as a collection of small hypoechoic structures in the confluence of the mediastinum testis. The clinical importance of these entity remains on... more
The cystic ectasia of the rete testis is a benign entity with a typical ultrasound appearance as a collection of small hypoechoic structures in the confluence of the mediastinum testis. The clinical importance of these entity remains on doing an adequate differential diagnosis with testicular neoplasias with a cystic component. We retrospectively reviewed the database of the Ultrasound Unit in the Department of Urology looking for patients with a diagnosis of cystic ectasia of the rete testis over a six-year period. Three cases of cystic ectasia of the rete testis were diagnosed over the six-year period, in all the indication for ultrasound was testicular pain. Mean patient age was 62 years. No patient developed testicular tumor on follow-up. The knowledge of the ultrasound characteristics found in the cystic ectasia of the rete testis helps to make a proper diagnosis of this benign entity without the need of indication of testicular biopsy.
Research Interests:
Research Interests:
Research Interests:
Kinetics corrosion of NiCrAlCoY thermal flame spray coating are reported. This coating was exposed to LiBr-H2O (wt. 50%) at 25 and 70° C during 10 days. The electrochemical noise (EN) technique and lineal polarization resistance (LPR)... more
Kinetics corrosion of NiCrAlCoY thermal flame spray coating are reported. This coating was exposed to LiBr-H2O (wt. 50%) at 25 and 70° C during 10 days. The electrochemical noise (EN) technique and lineal polarization resistance (LPR) were applied. NiCrAlCoY coating ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
One arising challenge in the treatment of breast cancer is the development of therapeutic resistance to trastuzumab, an antibody targeting the human epidermal growth factor receptor-2 (HER2), which is frequently amplified in breast... more
One arising challenge in the treatment of breast cancer is the development of therapeutic resistance to trastuzumab, an antibody targeting the human epidermal growth factor receptor-2 (HER2), which is frequently amplified in breast cancers. In this study, we provide evidence that elevated level of the receptor tyrosine kinase Eph receptor A2 (EphA2) is an important contributor to trastuzumab resistance. In a screen of a large cohort of human breast cancers, we found that EphA2 overexpression correlated with a decrease in disease-free and overall survival of HER2-overexpressing patients. Trastuzumab-resistant cell lines overexpressed EphA2, whereas inhibiting EphA2 restored sensitivity to trastuzumab treatment in vivo. Notably, trastuzumab treatment could promote EphA2 phosphorylation by activating Src kinase, leading in turn to an amplification of phosphoinositide 3-kinase/Akt and mitogen-activated protein kinase signaling in resistant cells. Our findings offer mechanistic insights into the basis for trastuzumab resistance and rationalize strategies to target EphA2 as a tactic to reverse trastuzumab resistance.