100 research outputs found

    Microbiological Communities and Properties of Arctic Soils: Results of the Tundra Northwest Expedition 1999 (Nunavut and Northwest Territories, Canada)

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    Protein import machineries in endosymbiotic organelles

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    Abstract.: Chloroplast and mitochondria, the two organelles with an accepted endosymbiotic origin, have developed multiple translocation pathways to ensure the subcellular allocation of proteins synthesized by cytosolic ribosomes, and to guarantee their assembly into functional complexes in coordination also with organellar-encoded subunits. The evolution of different protein import machineries was thus essential for the development of these two organelles within cells. A general overview of the translocation machineries in chloroplast and mitochondrial membranes involved in targeting and import of nuclearencoded proteins, with special focus on plant cells where the two organelles coexist, is expounde

    DOC-turnover and microbial biomass production

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    Uptake data of seven sugars (mono- and disaccharides) were used to calculate DOC-turnover and microbial biomass production. The sugars investigated in this study represent 1-2% of the DOC and up to30 % of the free dissolved carbohydrates. The uptake measurements were not based on a kinetic approach. Uniformly labelled 14C-carbohydrates were added to the samples, the concentrations reaching maximally 10% of the corresponding natural substrate concentration. Taking the natural substrate concentration into account, it is possible to calculate the actual uptake rates, turnover times and microbial C-production. An investigation in the Kiel Fjord during 1978/79 shows turnover times for glucose between 1.7 and 600 hours. The microbial biomass production varies between 0.01 and 10 ÎŒg C l-1 h-1, i.e. 0.2 - 83% of the primary production. The ratio between incorporation and gross uptake is between 0.62 and 0.95, which supports the assumption that free dissolved carbohydrates are biochemically wellutilized substrates. The relation to exudates is discussed

    Combining Performance with Thermal Stability: Synthesis and Characterization of 5‐(3,5‐Dinitro‐1H‐pyrazol‐4‐yl)‐1H‐tetrazole and its Energetic Derivatives

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    In this study, we present the synthesis of 5‐(3,5‐dinitro‐1H‐pyrazol‐4‐yl)‐1H‐tetrazole and its energetic derivatives starting from 4‐amino‐3,5‐dinitropyrazole, which was diazotized and cyanide substituted. A subsequent cycloaddition reaction with sodium azide led to 5‐(3,5‐dinitro‐1H‐pyrazol‐4‐yl)‐1H‐tetrazole (3). Several alkaline metal and nitrogen‐rich salts were prepared and characterized by low‐temperature X‐ray diffraction. Additionally, all compounds were analyzed by vibrational spectroscopy (IR), 1H, 13C and 14N NMR spectroscopy, elemental analysis and differential thermal analysis (DTA). Additionally, the heats of formation for selected compounds were calculated using the atomization method based on CBS‐4M enthalpies as well as important detonation parameters by using the EXPLO5 code (V6.05). Furthermore, the sensitivities of 3 and all synthesized salts toward friction, impact and electrostatic discharge according to BAM (Bundesamt fĂŒr Materialforschung) were determined and compared to RDX

    The implementation of initial data populations of environmental data and creation of a primary working database

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    Biological and environmental changes are creating a growing demand for historical and global data sets. Comparing up-to-date ecological and biological findings with historical statements has become a major part of scientific work in the field of ecology. This evaluation and comparison procedure is very time-consuming while the availability of raw data is very low. Comparisons between original findings – if available – require a lot of work from print publication to digitalization or transformation to appropriate data formats. The effective use of working capacity is a general issue and has become important, should the use of information technologies be invoked to minimize time-wasting copy and paste operations. In this paper we aim to present a working repository for terrestrial biological data. The implementation of this type of data repository will provide various services to participating scientists as long as the final aim is the publication of these repositories. Furthermore, the security and long-term availability of environmental data is an issue of increasing importance to the scientific community. Unrepeatable sampling events and any data thus obtained are precious in time series analysis. For this reason, a well-structured storage of data is necessary for easy accessibility, retrieval and comparability. This is an important issue for the community of environmental scientists. The need to construct and implement repositories should prevail against all hitches and we are therefore describing our on-going task with the primary population of this kind of data repository. A biological and ecological information system is a matter of public interest and should also be a key issue for ecologists

    The microphytobenthos of Königshafen — spatial and seasonal distribution on a sandy tidal flat

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    A microphytobenthic species composition of a tidal flat in the northern Wadden Sea was analysed regarding cell numbers and biomass (in carbon units). The three sampling sites differed in tidal inundation from 15 cm to about 90 cm water depth at high tide. The sediment was sandy at all three stations. A cluster analysis revealed a separation of the benthic diatoms into three areas: aNereis-Corophium-belt, a seagrass-bed and theArenicola-flat. Small epipsammic diatoms were most abundant and dominated the microalgal biomass. A microphytobenthic “spring bloom” even started beneath the ice cover of the flat in January. Lowest values of cell numbers and biomass of benthic microalgae were found in summer. Highest values were measured in the uppermost area (Nereis-Corophium-belt), and only here was an autumnal increase of benthic microalgae found. Further cluster analysis within each of the three areas revealed seasonal differences although the majority of species were present all year round. Many species were most abundant in spring, and some showed a bimodal distribution (spring-autumn) in the year of investigatio

    Some like it cold: understanding the survival strategies of psychrophiles

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    Much of the Earth's surface, both marine and terrestrial, is either periodically or permanently cold. Although habitats that are largely or continuously frozen are generally considered to be inhospitable to life, psychrophilic organisms have managed to survive in these environments. This is attributed to their innate adaptive capacity to cope with cold and its associated stresses. Here, we review the various environmental, physiological and molecular adaptations that psychrophilic microorganisms use to thrive under adverse conditions. We also discuss the impact of modern “omic” technologies in developing an improved understanding of these adaptations, highlighting recent work in this growing field.http://embor.embopress.org/content/15/5/508hb201

    Challenges in supporting lay carers of patients at the end of life: results from focus group discussions with primary healthcare providers

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    Background: Family caregivers (FCGs) of patients at the end of life (EoL) cared for at home receive support from professional and non-professional care providers. Healthcare providers in general practice play an important role as they coordinate care and establish contacts between the parties concerned. To identify potential intervention targets, this study deals with the challenges healthcare providers in general practice face in EoL care situations including patients, caregivers and networks. Methods: Focus group discussions with general practice teams in Germany were conducted to identify barriers to and enablers of an optimal support for family caregivers. Focus group discussions were analysed using content analysis. Results: Nineteen providers from 11 general practices took part in 4 focus group discussions. Participants identified challenges in communication with patients, caregivers and within the professional network. Communication with patients and caregivers focused on non-verbal messages, communicating at an appropriate time and perceiving patient and caregiver as a unit of care. Practice teams perceive themselves as an important part of the healthcare network, but also report difficulties in communication and cooperation with other healthcare providers. Conclusion: Healthcare providers in general practice identified relational challenges in daily primary palliative care with potential implications for EoL care. Communication and collaboration with patients, caregivers and among healthcare providers give opportunities for improving palliative care with a focus on the patient-caregiver dyad. It is insufficient to demand a (professional) support network; existing structures need to be recognized and included into the care
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