49 research outputs found
Seismic velocity models based on wide-angle refraction and reflection profiles in Finland
Laajakulmaiseen taittumis- ja heijastusluotaukseen perustuvat seismiset tutkimukset (WARR) ovat olleet keskeisessä roolissa Fennoskandian kilven rakenteellisessa tutkimuksessa. 1980-luvulta lähtien niissä on kerätty tieteellisesti arvokasta dataa sekä tuotettu seismisiä kuoren nopeusmalleja, jotka eivät ole aiemmin olleet julkisesti saatavilla. Tämän raportin kuvailemassa työssä vanhat nopeusmallit ja laajakulmasektiot muokattiin helpommin käytettäviin formaatteihin ja tallennettiin turvallisesti tutkimusdatan säilytyspalvelu IDAan. IDAssa tutkimusdata on avoimesti saatavilla ja tietokokonaisuuksille on IDAssa pysyvät DOI-tunnisteet. Säilötyn datan käyttö on määritelty Creative Commons By Attribution version 4.0 -lisenssillä. Sama data tulee myös saataville Geologian tutkimuskeskuksen Hakku-palveluun. Saatavilla olevat kaksiulotteiset nopeusmallit on tallennettu muotoon, jossa seisminen nopeus on määritetty koordinaattien pisteissä eri syvyyksillä tekstitiedostoissa. Laajakulmasektiot on tallennettu standard IBM SEG-Y -muotoisina. Tässä raportissa kuvaillaan taittumis- ja heijastusluotaustutkimuksia, saatavilla olevaa dataa sekä sen käyttöä.Seismic wide-angle refraction and reflection (WARR) surveys have been crucial in the study of the structure of the Fennoscandian shield. The valuable data and crustal seismic velocity models of major WARR studies from the 1980s to the present day have not been previously available to the public. In the work described in this report, the velocity models and wide-angle data were re-formatted to more accessible data formats and safely stored in the IDA Research Data Storage service for open access and data identification through Digital Object Identifiers. Data use is allowed under the Creative Commons By Attribution version 4.0 license. The data is also made available through the Hakku service of the Geological Survey of Finland. The velocity models are stored in a universal velocity point format in text files and wide-angle sections are stored in standard IBM SEG-Y format. A general description of WARR studies, available data and data use is given in this report
Seismic velocity models based on wide-angle refraction and reflection profiles in Finland
Laajakulmaiseen taittumis- ja heijastusluotaukseen perustuvat seismiset tutkimukset (WARR) ovat olleet keskeisessä roolissa Fennoskandian kilven rakenteellisessa tutkimuksessa. 1980-luvulta lähtien niissä on kerätty tieteellisesti arvokasta dataa sekä tuotettu seismisiä kuoren nopeusmalleja, jotka eivät ole aiemmin olleet julkisesti saatavilla. Tämän raportin kuvailemassa työssä vanhat nopeusmallit ja laajakulmasektiot muokattiin helpommin käytettäviin formaatteihin ja tallennettiin turvallisesti tutkimusdatan säilytyspalvelu IDAan. IDAssa tutkimusdata on avoimesti saatavilla ja tietokokonaisuuksille on IDAssa pysyvät DOI-tunnisteet. Säilötyn datan käyttö on määritelty Creative Commons By Attribution version 4.0 -lisenssillä. Sama data tulee myös saataville Geologian tutkimuskeskuksen Hakku-palveluun. Saatavilla olevat kaksiulotteiset nopeusmallit on tallennettu muotoon, jossa seisminen nopeus on määritetty koordinaattien pisteissä eri syvyyksillä tekstitiedostoissa. Laajakulmasektiot on tallennettu standard IBM SEG-Y -muotoisina. Tässä raportissa kuvaillaan taittumis- ja heijastusluotaustutkimuksia, saatavilla olevaa dataa sekä sen käyttöä.Seismic wide-angle refraction and reflection (WARR) surveys have been crucial in the study of the structure of the Fennoscandian shield. The valuable data and crustal seismic velocity models of major WARR studies from the 1980s to the present day have not been previously available to the public. In the work described in this report, the velocity models and wide-angle data were re-formatted to more accessible data formats and safely stored in the IDA Research Data Storage service for open access and data identification through Digital Object Identifiers. Data use is allowed under the Creative Commons By Attribution version 4.0 license. The data is also made available through the Hakku service of the Geological Survey of Finland. The velocity models are stored in a universal velocity point format in text files and wide-angle sections are stored in standard IBM SEG-Y format. A general description of WARR studies, available data and data use is given in this report
Deletion of the Stress Response Gene \u3ci\u3eDDR48\u3c/i\u3e From \u3ci\u3eHistoplasma capsulatum\u3c/i\u3e Increases Sensitivity to Oxidative Stress, Increases Susceptibility to Antifungals, and Decreases Fitness In Macrophages
The stress response gene DDR48 has been characterized in Saccharomyces cerevisiae and Candida albicans to be involved in combating various cellular stressors, from oxidative agents to antifungal compounds. Surprisingly, the biological function of DDR48 has yet to be identified, though it is likely an important part of the stress response. To gain insight into its function, we characterized DDR48 in the dimorphic fungal pathogen Histoplasma capsulatum. Transcriptional analyses showed preferential expression of DDR48 in the mycelial phase. Induction of DDR48 in Histoplasma yeasts developed after treatment with various cellular stress compounds. We generated a ddr48∆ deletion mutant to further characterize DDR48 function. Loss of DDR48 alters the transcriptional profile of the oxidative stress response and membrane synthesis pathways. Treatment with ROS or antifungal compounds reduced survival of ddr48∆ yeasts compared to controls, consistent with an aberrant cellular stress response. In addition, we infected RAW 264.7 macrophages with DDR48-expressing and ddr48∆ yeasts and observed a 50% decrease in recovery of ddr48∆ yeasts compared to wild-type yeasts. Loss of DDR48 function results in numerous negative effects in Histoplasma yeasts, highlighting its role as a key player in the global sensing and response to cellular stress by fungi
Biology of moderately halophilic aerobic bacteria
The moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. The property of halophilism is widespread within the bacterial domain. Bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. Most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. Complex mechanisms of adjustment of the intracellular environments and the properties of the cytoplasmic membrane enable rapid adaptation to changes in the salt concentration of the environment. Approaches to the study of genetic processes have recently been developed for several moderate halophiles, opening the way toward an understanding of haloadaptation at the molecular level. The new information obtained is also expected to contribute to the development of novel biotechnological uses for these organisms
Metabolism of halophilic archaea
In spite of their common hypersaline environment, halophilic archaea are surprisingly different in their nutritional demands and metabolic pathways. The metabolic diversity of halophilic archaea was investigated at the genomic level through systematic metabolic reconstruction and comparative analysis of four completely sequenced species: Halobacterium salinarum, Haloarcula marismortui, Haloquadratum walsbyi, and the haloalkaliphile Natronomonas pharaonis. The comparative study reveals different sets of enzyme genes amongst halophilic archaea, e.g. in glycerol degradation, pentose metabolism, and folate synthesis. The carefully assessed metabolic data represent a reliable resource for future system biology approaches as it also links to current experimental data on (halo)archaea from the literature
A local glucose-and oxygen concentration-based insulin secretion model for pancreatic islets
<p>Abstract</p> <p>Background</p> <p>Because insulin is the main regulator of glucose homeostasis, quantitative models describing the dynamics of glucose-induced insulin secretion are of obvious interest. Here, a computational model is introduced that focuses not on organism-level concentrations, but on the quantitative modeling of local, cellular-level glucose-insulin dynamics by incorporating the detailed spatial distribution of the concentrations of interest within isolated avascular pancreatic islets.</p> <p>Methods</p> <p>All nutrient consumption and hormone release rates were assumed to follow Hill-type sigmoid dependences on local concentrations. Insulin secretion rates depend on both the glucose concentration and its time-gradient, resulting in second-and first-phase responses, respectively. Since hypoxia may also be an important limiting factor in avascular islets, oxygen and cell viability considerations were also built in by incorporating and extending our previous islet cell oxygen consumption model. A finite element method (FEM) framework is used to combine reactive rates with mass transport by convection and diffusion as well as fluid-mechanics.</p> <p>Results</p> <p>The model was calibrated using experimental results from dynamic glucose-stimulated insulin release (GSIR) perifusion studies with isolated islets. Further optimization is still needed, but calculated insulin responses to stepwise increments in the incoming glucose concentration are in good agreement with existing experimental insulin release data characterizing glucose and oxygen dependence. The model makes possible the detailed description of the intraislet spatial distributions of insulin, glucose, and oxygen levels. In agreement with recent observations, modeling also suggests that smaller islets perform better when transplanted and/or encapsulated.</p> <p>Conclusions</p> <p>An insulin secretion model was implemented by coupling local consumption and release rates to calculations of the spatial distributions of all species of interest. The resulting glucose-insulin control system fits in the general framework of a sigmoid proportional-integral-derivative controller, a generalized PID controller, more suitable for biological systems, which are always nonlinear due to the maximum response being limited. Because of the general framework of the implementation, simulations can be carried out for arbitrary geometries including cultured, perifused, transplanted, and encapsulated islets.</p