Ensayos no destructivos aplicados a la caracterización de estructuras y materiales de construcción

Los materiales de construcción utilizados en edificaciones presentan un comportamiento mecánico que puede variar con las propiedades específicas del material utilizado, con las condiciones de contorno o con el ambiente al que se encuentra sometido. La utilización y desarrollo de técnicas o métodos de caracterización de los diferentes materiales de forma no destructiva posibilita conocer ciertas propiedades físicas y mecánicas sin necesidad de realizar ensayos de rotura. En este sentido, el presente trabajo presenta la implementación de métodos no destructivos y los resultados de aplicaciones a materiales de construcción para el diagnóstico de estructuras. Primero se estudia el comportamiento no lineal dinámico de elementos de hormigón, y sometidos a diferentes estados de carga mediante la respuesta dinámica de elementos de hormigón. Luego se desarrollan el trabajo realizado para le determinación de humedad en materiales de construcción utilizando ondas electromagnéticas, específicamente se plantea la determinación del contenido de humedad en muros fabricados con ladrillos cerámicos, ya sean huecos, como sólidos, y de fabricación artesanal como de fabricación industrial. Finalmente se presenta el estudio que el efecto de diferentes tipos de apoyo en la respuesta dinámica de vigas de madera. Los resultados obtenidos en probetas de hormigón muestran la dependencia de la respuesta dinámica con la carga de compresión, en los valores de frecuencia de resonancia torsional como en los parámetros vinculados a la de amortiguación. Se desarrolló una metodología para la determinación y cuantificación de humedad en mampostería cerámica. Por último se pudo verificar el efecto que diferentes tipos de apoyo tienen en el comportamiento no lineal dinámico de vigas de madera, sin encontrar diferencias significativas entre los apoyos analizados

Redox stress proteins are involved in adaptation response of the hyperthermoacidophilic archaeon Sulfolobus solfataricus to nickel challenge

<p>Abstract</p> <p>Background</p> <p>Exposure to nickel (Ni) and its chemical derivatives has been associated with severe health effects in human. On the contrary, poor knowledge has been acquired on target physiological processes or molecular mechanisms of this metal in model organisms, including Bacteria and Archaea. In this study, we describe an analysis focused at identifying proteins involved in the recovery of the archaeon <it>Sulfolobus solfataricus </it>strain MT4 from Ni-induced stress.</p> <p>Results</p> <p>To this purpose, <it>Sulfolobus solfataricus </it>was grown in the presence of the highest nickel sulphate concentration still allowing cells to survive; crude extracts from treated and untreated cells were compared at the proteome level by using a bi-dimensional chromatography approach. We identified several proteins specifically repressed or induced as result of Ni treatment. Observed up-regulated proteins were largely endowed with the ability to trigger recovery from oxidative and osmotic stress in other biological systems. It is noteworthy that most of the proteins induced following Ni treatment perform similar functions and a few have eukaryal homologue counterparts.</p> <p>Conclusion</p> <p>These findings suggest a series of preferential gene expression pathways activated in adaptation response to metal challenge.</p

Giant lysosomes as a chemotherapy resistance mechanism in hepatocellular carcinoma cells

Despite continuous improvements in therapeutic protocols, cancer-related mortality is still one of the main problems facing public health. The main cause of treatment failure is multi-drug resistance (MDR: simultaneous insensitivity to different anticancer agents), the underlying molecular and biological mechanisms of which include the activity of ATP binding cassette (ABC) proteins and drug compartmentalisation in cell organelles. We investigated the expression of the main ABC proteins and the role of cytoplasmic vacuoles in the MDR of six hepatocellular carcinoma (HCC) cell lines, and confirmed the accumulation of the yellow anticancer drug sunitinib in giant (four lines) and small cytoplasmic vacuoles of lysosomal origin (two lines). ABC expression analyses showed that the main ABC protein harboured by all of the cell lines was PGP, whose expression was not limited to the cell membrane but was also found on lysosomes. MTT assays showed that the cell lines with giant lysosomes were more resistant to sorafenib treatment than those with small lysosomes (p,0.01), and that verapamil incubation can revert this resistance, especially if it is administered after drug pre-incubation. The findings of this study demonstrate the involvement of PGP-positive lysosomes in drug sequestration and MDR in HCC cell lines. The possibility of modulating this mechanism using PGP inhibitors could lead to the development of new targeted strategies to enhance HCC treatment

Prevalence and etiology of community-acquired pneumonia in immunocompromised patients

Background. The correct management of immunocompromised patients with pneumonia is debated. We evaluated the prevalence, risk factors, and characteristics of immunocompromised patients coming from the community with pneumonia. Methods. We conducted a secondary analysis of an international, multicenter study enrolling adult patients coming from the community with pneumonia and hospitalized in 222 hospitals in 54 countries worldwide. Risk factors for immunocompromise included AIDS, aplastic anemia, asplenia, hematological cancer, chemotherapy, neutropenia, biological drug use, lung transplantation, chronic steroid use, and solid tumor. Results. At least 1 risk factor for immunocompromise was recorded in 18% of the 3702 patients enrolled. The prevalences of risk factors significantly differed across continents and countries, with chronic steroid use (45%), hematological cancer (25%), and chemotherapy (22%) the most common. Among immunocompromised patients, community-acquired pneumonia (CAP) pathogens were the most frequently identified, and prevalences did not differ from those in immunocompetent patients. Risk factors for immunocompromise were independently associated with neither Pseudomonas aeruginosa nor non\u2013community-acquired bacteria. Specific risk factors were independently associated with fungal infections (odds ratio for AIDS and hematological cancer, 15.10 and 4.65, respectively; both P = .001), mycobacterial infections (AIDS; P = .006), and viral infections other than influenza (hematological cancer, 5.49; P < .001). Conclusions. Our findings could be considered by clinicians in prescribing empiric antibiotic therapy for CAP in immunocompromised patients. Patients with AIDS and hematological cancer admitted with CAP may have higher prevalences of fungi, mycobacteria, and noninfluenza viruses

Highly sensitive detection of chemically modified thio‐organophosphates by an enzymatic biosensing device: an automated robotic approach

Pesticides represent some of the most common man‐made chemicals in the world. Despite their unquestionable utility in the agricultural field and in the prevention of pest infestation in public areas of cities, pesticides and their biotransformation products are toxic to the environment and hazardous to human health. Esterase‐based biosensors represent a viable alternative to the expensive and time‐consuming systems currently used for their detection. In this work, we used the esterase‐2 from Alicyclobacillus acidocaldarius as bioreceptor for a biosensing device based on an automated robotic approach. Coupling the robotic system with a fluorescence inhibition assay, in only 30 s of enzymatic assay, we accomplished the detection limit of 10 pmol for 11 chemically oxidized thio‐organophosphates in solution. In addition, we observed differences in the shape of the inhibition curves determined measuring the decrease of esterase‐2 residual activity over time. These differences could be used for the characterization and identification of thio‐organophosphate pesticides, leading to a pseudo fingerprinting for each of these compounds. This research represents a starting point to develop technologies for automated screening of toxic compounds in samples from industrial sectors, such as the food industry, and for environmental monitoring

Hormonogenic donor Tyr2522 of bovine thyroglobulin. Insight into preferential T3 formation at thyroglobulin carboxyl terminus at low iodination level

tryptic fragment (b5TR,NR), encompassing residues 2515-2750, was isolated from a low-iodine (0.26% by mass) bovine thyroglobulin, by limited proteolysis with trypsin and preparative, continuous-elution SDS-PAGE. The fragment was digested with Asp-N endoproteinase and analyzed by reverse-phase HPLC electrospray ionization quadrupole time-of-flight mass spectrometry, revealing the formation of: 3-monoiodotyrosine and dehydroalanine from Tyr2522; 3-monoiodotyrosine from Tyr2555 and Tyr2569; 3-monoiodotyrosine and 3,5-diiodotyrosine from Tyr2748. The data presented document, by direct mass spectrometric identifications, efficient iodophenoxyl ring transfer from monoiodinated hormonogenic donor Tyr2522 and efficient mono- and diiodination of hormonogenic acceptor Tyr2748, under conditions which permitted only limited iodination of Tyr2555 and Tyr2569, in low-iodine bovine thyroglobulin. The present study thereby provides: (1) a rationale for the preferential synthesis of T3 at the carboxy-terminal end of thyroglobulin, at low iodination level; (2) confirmation for the presence of an interspecifically conserved hormonogenic donor site in the carboxy-terminal domain of thyroglobulin; (3) solution for a previous uncertainty, concerning the precise location of such donor site in bovine thyroglobuli