Browsing by Author "Martinez, C."

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    Chitosan-triclosan particles modulate inflammatory signaling in gingival fibroblasts
    (2018) Pavez, L.; Tobar, N.; Chacon, C.; Arancibia, R.; Martinez, C.; Tapia, C.; Pastor, A.; Gonzalez, M.; Martinez, J.; Smith, P. C.
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    Effect of Sn content on the passivity of Ti-Ta-Sn alloys
    (2023) Valverde, B.; Sancy, M.; Martinez, C.; Botello, E.; Pio, E.; Aguilar, C.
    In this work, Ti-13Ta-xSn samples were manufactured using the powder metallurgy technique with a porosity near 35 %. The microstructural analysis revealed that increased Sn content decreased the alpha-Ti and alpha'-Ti phases. Furthermore, scanning electron microscopy and X-ray photoelectron spectroscopy showed that the chemical composition of the passive oxide film was influenced by the Sn content. Moreover, the electrochemical analysis revealed that the protective properties of oxide film improved with the Sn addition.
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    Evaluation of direct immunofluorescent assay (DFA) and rapid antigen test (RAT) for diagnosis of new pandemic influenza A H1N1 2009 (FLU AH1N1) during first wave in Santiago, Chile
    (ELSEVIER SCI LTD, 2010) Vizcaya, C.; Ferres, M.; Perret Pérez, Cecilia; Martinez, C.; Godoy, P.; Contreras, A. M.; Ferrer, P.; Azocar, T.
    Background: Since May 17th 2009 (epidemiological week 20th), the new strain of influenza A H1N1 was detected in respiratory samples of symptomatic patients in Santiago, Chile. The circulation of the virus lasted 11 weeks, with a peak between weeks 25-27th. The objective of our study was to evaluate the performance of influenza tests for diagnosis of FLU AH1N1. Methods: Nasopharyngeal swabs were taken from in and outpatients with influenza like illness (ILI), between June 1st and July 19th of 2009 (weeks 23-29th) and the results of DFA and RAT were compared using RT-PCR FLU AH1N1 (Light mix Kit Influenza A virus M2 and Light Mix Kit FLU A swine H1Ò of TIB MOLBIOL) as gold standard. We analyzed sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of DFA (D3 Ultra 8 DFA Respiratory & Identification Kit ä de Diagnostic Hybrid) and RAT (QuickVeuÒ of Biomerieux). Results were compared by age group and over three different periods of the outbreak: increasing, peak and decreasing. Results: 510 patients had RT-PCR for FLU AH1N1 with simultaneous DFA, 385 with RAT and 48 with both tests. Average age with DFA was 25,8 years (1 month-108 years, 53% females) and with RAT 32,9 years (2 months-108 years, 51% females), (p <0,0001). Comparing periods of the outbreak, DFA sensitivity was 58%, 77% and 81% in ascending, peak and descending period, respectively (p <0,001) and specificity was 90%, 83% and 91% respectively (p>0,05). Evaluating RAT, sensitivity was 41%, 61% and 67% (p<0,001) and specificity was 87%, 96% y 92% (p> 0,05) in different periods.
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    Evolution of synthesis of FCC nanocrystalline solid solution and amorphous phase in the Ti-Ta based alloy by high milling energy
    (2021) Aguilar, C.; Pio, E.; Medina, A.; Martinez, C.; Sancy, M.; Guzman, D.
    Pure Ti and Ti-based alloys exhibit two equilibrium phases: at lower temperatures they have a hexagonal close packed (alpha-Ti) crystalline structure while at higher temperatures they possess a body-centered cubic (beta-Ti) structure. However, in special conditions, they could exhibit a metastable face-centered cubic (gamma-Ti) crystalline structure. This paper aims to investigate the influence of Sn amount and milling time on the formation of gamma-Ti phase on the Ti-Ta based alloy. Four alloys with compositions Ti-13Ta-xSn (x: 3, 6, 9 and 12 at. %) were obtained by high energy milling. The alloys were analyzed by X-ray diffaction patterns, transmission and scanning electron microscopy. For the Ti-13Ta-3Sn alloy, the beta-Ti phase is formed in greater quantity, similar to 70% at 100 h. For the Ti-13Ta-6Sn and Ti-13Ta-9Sn alloys, the phase that is in greater quantity is gamma-Ti, around 100% at 100h. The Ti-13Ta-6Sn alloy shows a greater tendency to form the gamma-Ti phase, since the quantity is close to 100% at 50 h milling time. Thermodynamic calculations are comparable with experimental data. The calculations were made using the MAAT software based on Miedema's model. The MAAT is a free software that can be download from www.rpm.usm.cl. (C) 2020 Elsevier B.V. All rights reserved.
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    Fleas and Ticks in Carnivores From a Domestic–Wildlife Interface: Implications for Public Health and Wildlife
    (2016) Poo, D.; Elizondo, C.; Escobar, L.; Astorga, F.; Bermudez, S.; Martinez, C.; Abarca Villaseca, Katia; Medina, G.
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    Gingival Wound Healing: An Essential Response Disturbed by Aging?
    (2015) Smith, P. C.; Caceres, M.; Martinez, C.; Oyarzun, A.; Martinez, J.
    Gingival wound healing comprises a series of sequential responses that allow the closure of breaches in the masticatory mucosa. This process is of critical importance to prevent the invasion of microbes or other agents into tissues, avoiding the establishment of a chronic infection. Wound healing may also play an important role during cell and tissue reaction to long-term injury, as it may occur during inflammatory responses and cancer. Recent experimental data have shown that gingival wound healing is severely affected by the aging process. These defects may alter distinct phases of the wound-healing process, including epithelial migration, granulation tissue formation, and tissue remodeling. The cellular and molecular defects that may explain these deficiencies include several biological responses such as an increased inflammatory response, altered integrin signaling, reduced growth factor activity, decreased cell proliferation, diminished angiogenesis, reduced collagen synthesis, augmented collagen remodeling, and deterioration of the proliferative and differentiation potential of stem cells. In this review, we explore the cellular and molecular basis of these defects and their possible clinical implications.
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    GPD1 and ADH3 Natural Variants Underlie Glycerol Yield Differences in Wine Fermentation
    (2018) Tapia, S. M.; Cuevas, M.; Abarcao, V.; Delgado Hernández, Verónica Melissa; Rojas Jorquera, Vicente Alberto; Garcia, V.; Brice, C.; Martinez, C.; Salinas, F.; Larrondo Castro, Luis Fernando; Cubillos, F. A.
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    High-Speed Resistance Training in Older Women: The Role of Supervision
    (2017) Ramirez, R.; Martinez, C.; De la Fuente, Carlos; Cadore, E.; Marques, M.; Nakamura, F.; Loturco, I.; Caniuqueo, A.; Canas, R.; Izquierdo, M.
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    Improving mechanical properties and antibacterial response of a/b ternary Ti-Ta alloy foams for biomedical uses
    (2023) Aguilar, C.; Martin, F. San; Martinez, C.; Camara, B.; Claverias, F.; Undabarrena, A.; Sancy, M.; Salinas, V.; Munoz, L.
    This study investigates the potential of Ti-Ta-Sn alloys for biomedical applications due to their excellent mechanical properties and biocompatibility, with a particular focus on their use in trabecular bone replacement. This work aims to analyze the influence that of Sn has on the mechanical properties and antibacterial response of a -b ternary Ti-13Ta-xSn (x:3, 6, 9, and 12 at.%) alloy foams. The Ti-based alloys were designed considering three aspects; (i) final microstructure, (ii) alloying element types, and (iii) thermodynamics while using MAAT and ThermoCalc software. The alloys were obtained by mechanical alloying, with used milling times being 30 h for Ti-13Ta-3Sn, 10 h for Ti-13Ta-6Sn, 10 h for Ti-13Ta-9Sn, and 15 h for Ti-13Ta-12Sn. The foams were obtained using NaCl as the space holder (50 v/v% porosity) and consolidated by a hot pressing method at 780 & DEG;C for 30 min, applying a load of 40 MPa. Both the Staphylococcus aureus ATCC 6538 strain and Escherichia coli ATCC 8739 strain were used to evaluate the antibacterial responses of Ti-based alloy foams. The Ti-based alloy foams were composed mostly by a mix of a and b-phases. The metallic foams exhibited relative homogeneous pore distribution with a size between 100 and 450 mm and having an average porosity slightly higher than 50%. The samples showed elastic modulus values be-tween 1 and 2 GPa, compressive yield strengths over 150 MPa, and microhardness over 450 HV. All Ti-based alloy foams showed no antibacterial activity nor bacterial adhesion, indicating that there is bacterial adhesion inhibition.& COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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    Influence of the synthesis technique on tribological behavior of a Ti-6Al-4V alloy
    (2020) Martinez, C.; Briones, F.; Araya, N.; Aguilar, C.; Machado, I.; Guerra Figueroa, Carolina Andrea; Medina, A.; Sancy, Mamié
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    KAE1 Allelic Variants Affect TORC1 Activation and Fermentation Kinetics in Saccharomyces cerevisiae
    (2019) Kessi-Perez, E.I.; Salinas, F.; Gonzalez, A.; Su, Y.; Guillamon, J.M.; Hall, M.N.; Larrondo Castro, Luis Fernando; Martinez, C.
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    Molecular method for the detection of Andes hantavirus infection: validation for clinical diagnostics
    (2016) Vial, C.; Martinez, C.; Rios, S.; Martinez, J.; Vial, P.; Ferrés Garrido, Marcela Viviana; Rivera, J.; Perez, R.; Valdivieso, F.
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    Morphological changes in a cuspate sandy beach under persistent high-energy swells : Reriaca Beach (Chile)
    (2019) Agredano, Roberto; Cienfuegos Carrasco, Rodrigo Alberto; Catalan, P.; Mignot, E.; Bonneton, P.; Bonneton, N.; Martinez, C.
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    Risk factors for severe postoperative complications after gastrectomy for gastric and esophagogastric junction cancers
    (2019) Norero Muñoz, Enrique; Quezada, J.L.; Cerda, Jaime; Ceroni Villanelo, Marco; Martinez, C.; Mejia, R.; Munoz, R.; Araos, F.; Gonzalez, P.; Diaz, A.
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    Sonic Hedgehog Stimulates Proliferation of Human Periodontal Ligament Stem Cells
    (SAGE PUBLICATIONS INC, 2011) Martinez, C.; Smith, P. C.; Rodriguez, J. P.; Palma, V.
    Regulation of cell renewal in the periodontium is a critical cell function that has not been clarified. Sonic hedgehog (Shh) is a secreted signaling molecule that plays a key role during development and adult tissue homeostasis. In the present study, we have analyzed the role played by Shh in human periodontal ligament stem cell (HPLSC) proliferation. HPLSC were isolated with anti-STRO-1 antibodies. Shh increased the expression of GLI1 and PTC-1 and selectively stimulated cell proliferation in STRO-1(+) derived from adult periodontal ligament. Shh components were localized to primary cilia in STRO-1(+) cells after Shh stimulation. STRO-1(+) also expressed Shh, suggesting an autocrine-regulated phenomenon. Thus, we propose that Shh plays a critical role in the regulation of cell proliferation in STRO-1(+)/HPLSC.
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    Tribological Performance of Porous Ti-Nb-Ta-Fe-Mn Alloy in Dry Condition
    (2020) Guerra Figueroa, Carolina Andrea; Walczak, Magdalena; Sancy, Mamié; Martinez, C.; Aguilar, C.; Kalbarczyk, M.