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Este trabajo analiza el caso de Medtronic, una empresa dedicada a la producción de dispositivos médicos, tomando como punto de partida los modelos sistémicos de planeación estratégica enfocados en la tecnología y el desarrollo de producto. Asimismo, se analizan el ambiente interno de Medtronic, el ambiente de selección y el ambiente externo, los procesos de desarrollo de capacidades mediante adquisición de empresas y centros de I+D. Finalmente, se presenta una descripción de los efectos financieros a los que se enfrenta Medtronic y las oportunidades que la adquisición de Covidien le han brindado. [ABSTRACT FROM AUTHOR]

The Socompa volcano is one of the Holocene volcanoes of the Central Volcanic Zone of the Andes. Given that it records effusive activity after 5910 YBP and that recent studies reveal unrest associated with the uplift of its edifice, it is considered an active volcano. With the aim of explaining new features that provide information about the nature of its state, here we present a geoelectric structures model of the subsurface of Socompa volcano obtained with the magnetotelluric method. One of the main features defined by the 3-D model is a body with an electrical resistivity value lower than 10 Ωm between 2 and 7 km depth and located below the volcanic edifice. This body, interpreted as the magmatic heat source of the volcano, is connected to a shallow and thick high conductive layer that covers the surrounding area. Our results highlight a possible shallow magma reservoir below the Socompa volcano and an associated -active or not- hydrothermal system. • A magnetotelluric survey was carried out to image the resistivity distribution below Socompa volcano and its surroundings. • Conductive structures associated with a shallow magmatic reservoir and an hydrothermal system were inferred. • Socompa volcano presents conductive features comparable to those of other active volcanoes in the CVZ. [ABSTRACT FROM AUTHOR]

• The Central Andes are the largest undeveloped geothermal region in the world. • Geophysic method that use the natural variations of the electric and magnetic fields. • 3-D inversion is a promising technique to model and image geothermal reservoirs. • Low-resistivity layer is linked with the clay cap at the geothermal reservoir. • Conceptual model for high-temperature volcanic geothermal systems. The Tocomar Geothermal System is located in the Puna Plateau (NW Argentina), within the Central Puna Energy Hub, and is considered one of the most promising places to harness potential alternative of power and heat sources in the Central Andean Volcanic Zone (16-28 °S). It is related to the Calama-Olacapato-Toro lineament and to the Quaternary Tocomar volcanic centre. Moreover, it is surrounded by active and fossil geothermal manifestations, like hot-springs, travertines and siliceous sinter deposits. Despite some geological studies in the area, no geophysical investigations have targeted the geothermal fields along the Central Puna. In this work we present a 3-D inversion of audio-magnetotelluric data around the Tocomar Geothermal System. These data was obtained in the frequency range of 1000-0.1 Hz to map the main elements of the geothermal system (clay cap and potential reservoir) at depths of approximately 1000 m. To achieve this goal, previous geoelectrical studies, the local geology and the trend of the main structures were also considered. For the 3-D inversion process the ModEM code was used. The model shows a low-resistivity layer (less than 10 Ωm) at least 300 m thick, at a depth of about 200–500 m, aligned with both the strike of the Calama-Olacapato-Toro lineament and the local superficial geothermal manifestations (hot-springs and hydrothermally altered rocks). This low-resistivity layer is linked with the clay cap at the shallow depth of the geothermal reservoir. At depths greater than 800 m, a gradual increase in resistivity is observed related to a potential reservoir within the fractured Ordovician basement. The final 3-D resistivity model highly correlates with the conceptual models of high-temperature volcanic geothermal systems. [ABSTRACT FROM AUTHOR]

The microbial safety and stability of minimally processed foods are based on the application of combined preservative factors. Since microorganisms are able to develop adaptive networks to survive under conditions of stress, food safety may be affected, and therefore understanding of stress adaptive mechanisms plays a key role in designing safe food processing conditions. In the present study, the viability and the sublethal injury of Listeria monocytogenes exposed to moderate heat (55°C) and/or essential oil compounds (carvacrol and thymol, 0.3 mM) treatments were studied. Synergistic effects were obtained when combining mild heat (55°C) with one or both essential oil compounds, leading to inactivation kinetics values three to four times lower than when using heat alone. All the treatments applied caused some injury in the population. The injury levels ranged from around 20% of the surviving population under the mildest conditions to more than 99.99% under the most stringent conditions. Protein extracts of cells exposed to these treatments were analysed by two-dimensional gel electrophoresis. The results obtained revealed that stressed cells exhibited differential protein expression to control cells. The proteins upregulated under these stressing conditions were implicated, among other functions, in stress response, metabolism, and protein refolding. [ABSTRACT FROM AUTHOR]

The development of heterogeneous catalytic processes is highly desirable in order to overcome some drawbacks of homogeneous catalysts, such as the separation and recycling of these catalysts. In this work, we report that Jacobsen type catalysts are efficient and selective for the oxidation of R-(+)-limonene to its corresponding diepoxides using in situ generated dimethyldioxirane (DMD) as oxidant. It was demonstrated that the solid NaHCO3 addition to the initial reaction mixture, improves the catalytic activity. Additionally, catalyst samples can be recovered and reused at least twice without significant loss of its initial catalytic activity. [ABSTRACT FROM AUTHOR]

Abstract: The antimicrobial properties of oregano, rosemary and laurel extracts obtained by supercritical fluid extraction were investigated by examining their influence on the growth and viability of Listeria monocytogenes in laboratory medium and broccoli juice at 30 and 8°C. Important decreases in the L. monocytogenes population were shown in presence of all the extracts obtained from rosemary and one oregano extract. The counts were reduced below the level of detection after 4h of exposure at 30°C in laboratory medium. A bactericidal effect was observed also when L. monocytogenes was exposed to rosemary at 30°C and 8°C in broccoli juice. Significant reductions in growth rate and an increase in lag phase of L. monocytogenes were observed in presence of some of the laurel and oregano extracts at both temperatures. Flow cytometry was used as a rapid method to determine the antibacterial effect of supercritical extracts and the physiological state of L. monocytogenes. Bacterial viability performed by dual staining of L. monocytogenes with SYTO 9 and propidium iodide revealed three different cell populations, specifically, living, dead and compromised cells. Live cell percentage decreased with the time of exposure, whereas the percentage of compromised cells remained constant and the dead cells increased in the same period. [Copyright &y& Elsevier]

The Socompa stratovolcano is located in the Andean Central Volcanic Zone, where active volcanism turns it into an area of interest for geothermal resources. In the surroundings of the volcano, the Socompa Geothermal Prospect was carried out looking for thermal manifestations related to an active geothermal system. The results of these preliminary studies are not conclusive. Here we present a geoelectrical model from a 3-D inversion of audiomagnetotelluric data acquired in an area of 16 km2. It covers the topographic low where the Socompa lagoon and the thermal springs are located, in order to determine the reservoir of circulating geothermal waters. The most distinctive feature determined by the 3-D model is a high conductive layer (less than 10 Ωm) at a depth of about 400–500 m and at least 200 m thick. Due to the environment and the depth to which the conductive layer is found, there is more than one possibility to explain its presence. It could be due to a deep saline aquifer that would be hosting the circulating waters. But since the low topography could coincide with a cryptic caldera of Miocene - Pliocene(?) age, the high conductivity layer could also be explained by the presence of a clay cap developed during the period of activity. From the inversion of the audiomagnetotelluric data it was possible to carry out a geoelectrical characterization of the upper units present in the study area, as well as to delimit, in a first approximation, the depth to which the hydrothermal reservoir would be found. • The Socompa Geothermal Prospect is located in the Andean Central Volcanic Zone. • An audiomagnetotelluric survey was carried out in the Socompa Geothermal Prospect. • A high conductive layer at 400–500 m and at least 200 m thick was determined by the 3D model. • The main scenarios for the high conductivity layer are: a saline aquifer; a Mio-Piocene? clay cap. [ABSTRACT FROM AUTHOR]

The main aim of this work is to relate the geoelectrical units defined by the 3D model to the geological units in the southeast of the Tucumán plain, where geothermal manifestations are shown by artesian wells with temperatures between 38 °C and 50 °C. Two field campaigns involving 41 audio-magnetotelluric sites in the frequency range 100,000 to 10 Hz were carried on. Some sites are located near the wells, where the depth from which they bring water to the surface is known. The 3D model allows us to describe characteristics of the electrical resistivity of the different sedimentary formations as well as to correlate it with the structural features present in the region of study. The most remarkable feature of the final model is the high conductivity of the deepest geoelectrical unit associated with a formation of marine origin in which the presence of illite and montmorillonite has been determined. In addition, as some information from the wells is available for the layer taken advantage of, it was possible to validate the resistivity determined by the model with that obtained with Archie's law, finding correspondence. • The southeast of the Tucumán plain is an area of anomalous geothermal gradient with potential economic interest. • An audio-magnetotelluric (AMT) survey was carried out to characterize the main hydrogeological units. • Prior model and model covariance were parameters investigated for our distribution of AMT sites. • The resistivity of the model is in agreement with that obtained from Archie's law considering the information from the wells. • The model shows correspondence with the geological structures. [ABSTRACT FROM AUTHOR]

The Historic Sanctuary of Machu Picchu (Cusco, Peru) is one of the most important archaeological monuments in Peru and worldwide. Machu Picchu is classified as a UNESCO World Heritage site and at risk from climatic change. However, the seismic centennial history of Peru reports large earthquakes generated both along the subduction zone (Mw8) and on active crustal faults along the Andean Cordillera (Mw7). It is therefore important to know if Machu Picchu is located in an area of seismic hazard and then to take measures to mitigate potential seismic hazards. Due to the short historical earthquake catalogue (< 500 years) and the absence of significant recent instrumental seismicity in the site's vicinity (radius of < 30 km), our knowledge about the seismic hazard in Machu Picchu is limited. The earthquakes of 1650 and 1950 affected Cusco city and surrounding areas, but without damage descriptions in Machu Picchu (80 km away) (Silgado Ferro 1978). In this study, we make the first attempt to use the analysis of earthquake archaeological effects (EAEs) and their differentiation from the effects generated by slope movements (creep) to investigate the past occurrence of strong earthquakes at the site. The application of geological structural analysis to the deformations observed in Machu Picchu shows two directions of the mean ground movement: N020° E and N110° E. Two earthquakes that affected Machu Picchu during its construction generated these directions. This kind of data should be used in the future to protect this important archaeological site. [ABSTRACT FROM AUTHOR]

Background: The most widely used treatment of portal-systemic encephalopathy (PSE) is the administration of oral, non-absorbable disaccharides. Theoretically, the inhibition of intestinal disaccharidases should induce malabsorption of disaccharides and increase delivery of undigested carbohydrates to the colon, thus stimulating the effects of lactulose and other non-absorbable disaccharides (that is, lactitol and lactose). AO-128 is an N-substituted derivative of valeolamine, an aminocyclitol that selectively inhibits intestinal disaccharidases. This study was performed to investigate whether AO-128 could be used as adjuvant therapy for the treatment of mild PSE in cirrhotic patients. Methods: A double-blind, randomized, controlled trial was performed in 35 cirrhotic patients with PSE. Patients were given a 2-week treatment consisting of AO-128 (2 mg three times daily) or an identical placebo. The following featurers of PSE syndrome were assessed in a semiquantitative fashion before and after 1 and 2 weeks of therapy: mental state, asterixis, number connection test (NCT), venous blood ammonia concentration, electroencephalogram (EEG), and overall PSE index (PSEI). More patients receiving AO-128 than patients receiving placebo showed >40% improvement in the PSEI (83% versus 35%; P < 0.05). The mean stool pH decreased from 5.8 ± 0.3 to 5.5 ± 0.3 (P < 0.004) after AO-128 treatment, whereas no changes were observed in the placebo group. The EEG and nitrogen balance did not show significant changes in any of the two groups. A significant improvement was seen in the NCT performance after AO-128 (from grade 2.0 ± 1.04 to grade 1.25 ± 0.87; P < 0.05). Seven patients treated with AO-128 developed diarrhea, as compared with none in the placebo group (P < 0.05). Conclusion: These results suggest that AO-128 may be useful in the treatment of PSE, although further studies are required to establish the benefit of AO-128 and determine adequate individual doses. [ABSTRACT FROM AUTHOR]

During the last decade, gene therapy has emerged as a novel strategy for the treatment of several diseases. Regarding cardiovascular diseases, the genes of angiogenic growth factors have been successfully administered in animal models of ischemic diseases, combining gene therapy with the concept of therapeutic angiogenesis. Gene therapy is advantageous over protein therapy, since it can be considered a sophisticated form of a sustained delivery system. Moreover, gene therapy is cheaper to develop, implement and reimburse. Vascular endothelial growth factor (VEGF), an endothelial cell-specific mitogen, has shown angiogenic properties in vitro and in vivo. We hypothesized that administration of naked plasmid DNA encoding VEGF121 could promote therapeutic angiogenesis in animal models of hindlimb and myocardial ischemia. Unilateral hindlimb ischemia was surgically induced in Beagle dogs. Ten days later, animals received intramuscular injections of pVEGF121 plasmid or saline directly in the ischemic muscles. Thirty days after gene transfer, angiographically recognizable collateral vessels were increased in pVEGF121-treated animals compared with controls. Perfusion to the ischemic limb was improved, as assessed by calf blood pressure ratio and vasomotor reserve assays. Yorkshire swine underwent induction of myocardial ischemia. Four weeks later, pVEGF121 or saline was administered into the myocardium. Four weeks after gene transfer, SPECT imaging demonstrated significant improvement in myocardial perfusion and function for pVEGF121 group compared with controls. Our results suggest that intramuscular and intramyocardial gene transfer of VEGF121 as naked plasmid DNA may augment collateral development and tissue perfusion in peripheral vascular and coronary artery diseases, respectively. [ABSTRACT FROM AUTHOR]