Impedance-based health monitoring and mechanical testing of structures

Palomino, Lizeth Vargas,de Moura, Jose Dos Reis Vieira Jr.,Tsuruta, Karina Mayumi,Rade, Domingos Alves,Steffen, Valder Jr. Techno-Press 2011 Smart Structures and Systems, An International Jou Vol.7 No.1

The mechanical properties obtained from mechanical tests, such as tensile, buckling, impact and fatigue tests, are largely applied to several materials and are used today for preliminary studies for the investigation of a desired element in a structure and prediction of its behavior in use. This contribution focus on two widely used different tests: tensile and fatigue tests. Small PZT (Lead Titanate Zirconate) patches are bonded on the surface of test samples for impedance-based health monitoring purposes. Together with these two tests, the electromechanical impedance technique was performed by using aluminum test samples similar to those used in the aeronautical industry. The results obtained both from tensile and fatigue tests were compared with the impedance signatures. Finally, statistical meta-models were built to investigate the possibility of determining the state of the structure from the impedance signatures.

How to Die in Colombia: A Constitutional Dilemma

Estefania Palomino 이화여자대학교 생명의료법연구소 2017 Asia Pacific Journal of Health Law & Ethics Vol.10 No.2

In 1997, Colombia s Constitutional Court decriminalized the medical practice of euthanasia in patients with serious and incurable diseases. Decision C-239 became one of the most radical advancements on the right to die debates in the world. At the time, European countries who have led this discussion, such as the Netherlands, hadn t legalized and incorporated the right to die into their own legal systems. In 2015, Colombia s Constitutional Court authorized the first legal clinical euthanasia in the country through a constitutional process also known as tutela on behalf of 79-year old Ovidio González. Mr. González decided to die at a clinic due to the suffering that he was experiencing while battling throat cancer. In this paper, I analyze the reasoning behind Decision C-239 and the long pathway to its implementation in the first Latin American country to legalize euthanasia. I will also examine other constitutional actions presented by terminal patients in defense of their right to die. The objective of this article is to provide routes of constitutional strategic litigation for advocates in other countries by building upon Colombia s experience, and to study the role of the Constitutional Court in shaping ethical debates such as euthanasia.

Numerical simulation of reinforced concrete nuclear containment under extreme loads

Jorge Luis Palomino Tamayo,Armando Miguel Awruch 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.58 No.5

A finite element model for the non-linear dynamic analysis of a reinforced concrete (RC) containment shell of a nuclear power plant subjected to extreme loads such as impact and earthquake is presented in this work. The impact is modeled by using an uncoupled approach in which a load function is applied at the impact zone. The earthquake load is modeled by prescribing ground accelerations at the base of the structure. The nuclear containment is discretized spatially by using 20-node brick finite elements. The concrete in compression is modeled by using a modified Drücker-Prager elasto-plastic constitutive law where strain rate effects are considered. Cracking of concrete is modeled by using a smeared cracking approach where the tension-stiffening effect is included via a strain-softening rule. A model based on fracture mechanics, using the concept of constant fracture energy release, is used to relate the strain softening effect to the element size in order to guaranty mesh independency in the numerical prediction. The reinforcing bars are represented by incorporated membrane elements with a von Mises elasto-plastic law. Two benchmarks are used to verify the numerical implementation of the present model. Results are presented graphically in terms of displacement histories and cracking patterns. Finally, the influence of the shear transfer model used for cracked concrete as well as the effect due to a base slab incorporation in the numerical modeling are analyzed.

Impedance-based health monitoring and mechanical testing of structures

Lizeth Vargas Palomino,Valder Steffen Jr.,Jose dos Reis Vieira de Moura Jr.,Karina Mayumi Tsuruta,Domingos Alves Rade 국제구조공학회 2011 Smart Structures and Systems, An International Jou Vol.7 No.1

The mechanical properties obtained from mechanical tests, such as tensile, buckling, impact and fatigue tests, are largely applied to several materials and are used today for preliminary studies for the investigation of a desired element in a structure and prediction of its behavior in use. This contribution focus on two widely used different tests: tensile and fatigue tests. Small PZT (Lead Titanate Zirconate) patches are bonded on the surface of test samples for impedance-based health monitoring purposes. Together with these two tests, the electromechanical impedance technique was performed by using aluminum test samples similar to those used in the aeronautical industry. The results obtained both from tensile and fatigue tests were compared with the impedance signatures. Finally, statistical meta-models were built to investigate the possibility of determining the state of the structure from the impedance signatures.

Fabrication process of a microstructures based on hydrogenated amorphous SiGe films for applications in MEMS devices

M. Galindo-Mentle,F. López-Huerta,R. Palomino-Merino,C. Zúñiga-Islas,W. Calleja-Arriaga,A. L. Herrera-May 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.4

We present a fabrication process of microstructures using both boron-doped hydrogenated amorphous silicon and hydrogenated amorphoussilicon-germanium (a-SiB:H and a-Si0.5Ge0.5B:H) films for applications in devices based on microelectromechanical systems(MEMS). These microstructures are fabricated through plasma enhanced chemical vapor deposition (PECVD) with a low temperature of300°C at 110 kHz and a pressure of 0.6 Torr. The proposed microstructures have three different geometries (Diamond, cantilever andbridge) considering a single structural layer of 1 μm thickness and are fabricated using surface micromachining. The fabricated a-Si0.5Ge0.5B:H microstructures do not present sticking problems and have good mechanical stability, which can allow their use in MEMSdevices. Our fabrication process with hydrogenated amorphous SiGe films is simple. This process decreases the residual stress of themicrostructures and allows the metal deposition on the microstructures surfaces.

Deformation of ''tunable'' clay-polymer composites

Bishop, M.D.,Kim, S.,Palomino, A.M.,Lee, J.S. Elsevier 2014 Applied clay science Vol.101 No.-

Responsive clay-polymer composites are the next step in the development of polymer-modified clay materials. It has been shown at the micro-scale that these materials respond to the surrounding pore fluid environment, resulting in an alteration in fabric. The purpose of this study is to investigate the impact of the responsive nature of these materials on the consolidation properties. Two composite types were selected to highlight the differences based on modified interparticle and interparticle/interlayer spacings: one made from a kaolinite and one from a montmorillonite. Each composite was made with polyacrylamide as the polymer. The clay-polymer composites were subjected to 1-D consolidation tests during which shear wave velocity was also measured. The pH of the saturating fluid was varied to promote composite response. Results show that the compressibility, compression index, and swelling index of the composite materials are greater than the untreated clay materials. Furthermore, these properties are pH-dependent for both types of composite materials and are consistent with the long-term conformational behavior of PAM. This apparent observation confirms that the behavior of the clay-PAM composites is controlled by the behavior of PAM. On the other hand, the shear wave velocities between the control and composite samples were not significantly different.

Acute and Repeated 28-Day Oral Dose Toxicity Studies of Thymus vulgaris L. Essential Oil in Rats

Rojas-Armas, Juan,Arroyo-Acevedo, Jorge,Ortiz-Sanchez, Manuel,Palomino-Pacheco, Miriam,Castro-Luna, Americo,Ramos-Cevallos, Norma,Justil-Guerrero, Hugo,Hilario-Vargas, Julio,Herrera-Calderon, Oscar Korean Society of ToxicologyKorea Environmental Mu 2019 Toxicological Research Vol.35 No.3

Thymus vulgaris L. is widely used as an ingredient in cooking and in herbal medicine. However, there is little information about its toxicity. The present study was performed to evaluate the acute and repeated 28-day oral dose toxicity of thyme essential oil in rats. For the acute toxicity test, two groups of three rats were used. The rats received a single dose of essential oil: 300 or 2,000 mg/kg of body weight (bw). The rats were observed individually during the first four hours, and then daily until day 14. For the toxicity test with repeated doses, four groups of 10 rats were used. Doses of 100, 250, and 500 mg/kg/day were tested for 28 days. At the end of the experiment, blood was collected and the animals were sacrificed. Histopathological examination showed that in the lungs of rats given the 2,000 mg/kg bw dose, polymorph nuclear infiltrates, hemosiderin macrophages, and interstitial space thickening were present. In the repeated dose study, all rats survived the 28-day treatment period and apparently showed no signs of toxicity. The hematological and biochemical parameters were not altered. The histopathological study of the organs showed severe changes in the lung, with the dose of 500 mg/kg/day; in the other organs, no alterations were observed or the changes were slight. The body weight was only altered in male rats given the 500 mg/kg dose. The relative weight of the organs did not show any significant changes. Our studies revealed that the essential oil of Thymus vulgaris has moderate oral toxicity according to the results of the acute test, whereas the results of the 28-day oral toxicity test suggest that the no-observed-adverse effect level (NOAEL) is greater than 250 mg/kg/day.

Metal Biosorption by Surface-Layer Proteins from Bacillus Species

Mariana Claudia Allievi,Sabbione Florencia,Prado Acosta Mariano,Palomino Maria Mercedes,Ruzal Sandra M.,Sanchez Rivas Carmen 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.2

Bacillus species have been involved in metal association as biosorbents, but there is not a clear understanding of this chelating property. In order to evaluate this metal chelating capacity, cultures and spores from Gram-positive bacteria of species either able or unable to produce surface layer proteins (S-layers) were analyzed for their capacity of copper biosorption. Only those endowed of S-layers, like Bacillus sphaericus and B. thuringiensis, showed a significant biosorption capacity. This capacity (nearly 50%) was retained after heating of cultures, thus supporting that structural elements of the envelopes are responsible for such activity. Purified Slayers from two Bacillus sphaericus strains had the ability to biosorb copper. Copper biosorption parameters were determined for strain B. sphaericus 2362, and after analyses by means of the Langmuir model, the affinity and capacity were shown to be comparable to other bacterial biosorbents. A competitive effect of Ca2+ and Zn2+, but not of Cd2+, was also observed, thus indicating that other cations may be biosorbed by this protein. Spores that have been shown to be proficient for copper biosorption were further analyzed for the presence of Slayer content. The retention of S-layers by these spores was clearly observed, and after extensive treatment to eliminate the S-layers, the biosorption capacity of these spores was significantly reduced. For the first time, a direct correlation between S-layer protein content and metal biosorption capacity is shown. This capacity is linked to the retention of S-layer proteins attached to Bacillus spores and cells.

Gastrointestinal stromal tumors as an incidental finding in patients with a presumptive diagnosis of ovarian cancer

Mario Muñoz,Pedro T. Ramirez,Carolina Echeverri,Luis Guillermo Álvarez,Maria Alejandra Palomino,Luis René Pareja,정준철 대한부인종양학회 2012 Journal of Gynecologic Oncology Vol.23 No.1

Objective: To report the clinical presentation and oncologic outcomes of a series of patients who presented with an abdominal or pelvic mass and were diagnosed with a gastrointestinal stromal tumor (GIST). Methods: Data were obtained on all patients who presented with an abdominal or pelvic mass between September 2007 and June 2010 and who were ultimately diagnosed with a GIST. The patients’ medical records were reviewed. A literature review was also conducted. Results: Six patients were identified who met the inclusion criteria. All six patients had a tumor in the intestinal tract arising from the small bowel. The mean tumor size was 12 cm (range, 6 to 22 cm). A complete resection was achieved in five of the six patients. There were no intraoperative complications; one patient had a postoperative complication. Two patients were treated with imatinib after surgery. The mean follow-up time was 32 months (range, 0.3 to 40 months). At the last follow-up, five of the six patients were without any evidence of disease. One patient died of an unrelated hepatic encephalopathy. The incidence in our institution is 3%. Conclusion: GISTs are uncommon; however, they should be considered in the differential diagnosis of patients presenting with an abdominal or pelvic mass. Objective: To report the clinical presentation and oncologic outcomes of a series of patients who presented with an abdominal or pelvic mass and were diagnosed with a gastrointestinal stromal tumor (GIST). Methods: Data were obtained on all patients who presented with an abdominal or pelvic mass between September 2007 and June 2010 and who were ultimately diagnosed with a GIST. The patients’ medical records were reviewed. A literature review was also conducted. Results: Six patients were identified who met the inclusion criteria. All six patients had a tumor in the intestinal tract arising from the small bowel. The mean tumor size was 12 cm (range, 6 to 22 cm). A complete resection was achieved in five of the six patients. There were no intraoperative complications; one patient had a postoperative complication. Two patients were treated with imatinib after surgery. The mean follow-up time was 32 months (range, 0.3 to 40 months). At the last follow-up, five of the six patients were without any evidence of disease. One patient died of an unrelated hepatic encephalopathy. The incidence in our institution is 3%. Conclusion: GISTs are uncommon; however, they should be considered in the differential diagnosis of patients presenting with an abdominal or pelvic mass.

Acute and Repeated 28-Day Oral Dose Toxicity Studies of Thymus vulgaris L. Essential Oil in Rats

Juan Rojas Armas,Jorge Arroyo-Acevedo,Manuel Ortiz-Sánchez,Miriam Palomino-Pacheco,Américo Castro-Luna,Norma Ramos-Cevallos,Hugo Justil-Guerrero,Julio Hilario-Vargas,Oscar Herrera-Calderón 한국독성학회 2019 Toxicological Research Vol.35 No.3

Thymus vulgaris L. is widely used as an ingredient in cooking and in herbal medicine. However, there is little information about its toxicity. The present study was performed to evaluate the acute and repeated 28-day oral dose toxicity of thyme essential oil in rats. For the acute toxicity test, two groups of three rats were used. The rats received a single dose of essential oil: 300 or 2,000 mg/kg of body weight (bw). The rats were observed individually during the first four hours, and then daily until day 14. For the toxicity test with repeated doses, four groups of 10 rats were used. Doses of 100, 250, and 500 mg/kg/day were tested for 28 days. At the end of the experiment, blood was collected and the animals were sacrificed. Histopathological examination showed that in the lungs of rats given the 2,000 mg/kg bw dose, polymorph nuclear infiltrates, hemosiderin macrophages, and interstitial space thickening were present. In the repeated dose study, all rats survived the 28-day treatment period and apparently showed no signs of toxicity. The hematological and biochemical parameters were not altered. The histopathological study of the organs showed severe changes in the lung, with the dose of 500 mg/kg/day; in the other organs, no alterations were observed or the changes were slight. The body weight was only altered in male rats given the 500 mg/kg dose. The relative weight of the organs did not show any significant changes. Our studies revealed that the essential oil of Thymus vulgaris has moderate oral toxicity according to the results of the acute test, whereas the results of the 28-day oral toxicity test suggest that the no-observed-adverse effect level (NOAEL) is greater than 250 mg/kg/day.