143 research outputs found
High-resolution correlation of coastal cliff sections in the Lagos- Portimao Formation (Lower - Middle Miocene, central Algarve, Portugal)
This paper describes a high-resolution stratigraphic correlation scheme for the early to middle Miocene Lagos-Portimão
Formation of central Algarve, southern Portugal.
The Lagos Portimão-Formation of central Algarve is a 60 m thick package of horizontally bedded siliciclastics and carbonates. The bryozoan and mollusc dominated biofacies is typical of a shallow marine, warm-temperate climatic environment. We define four stratigraphic marker beds based on biofacies, lithology, and gamma-ray signatures. Marker bed 1 is a reddish shell bed composed predominantly of bivalve shells in various stages of fragmentation. Marker bed 2 is a fossiliferous sandstone / sandy rudstone characterized by bryozoan masses. Marker bed 3 is also a fossiliferous sandstone with abundant larger foraminifers and foliate bryozoans. Marker bed 4 is composed of three distinct layers; two fossiliferous sandstones with an intercalated shell bed. The upper sandstone unit displays thickets of the bryozoan Celleporaria palmate associated with the coral Culizia parasitica.
This stratigraphic framework allows to correlate isolated outcrops within the stratigraphic context of the Lagos-Portimão
Formation and to establish high resolution chronostratigraphic Sr-isotopic dating
Ca isotope fractionation of inorganic, biologically induced and biologically controlled calcium carbonates
Whole-genome sequencing reveals two prolonged simultaneous outbreaks involving Pseudomonas aeruginosa high-risk strains ST111 and ST235 with resistance to quaternary ammonium compounds
Objective
Water-bearing systems are known as frequent Pseudomonas aeruginosa (PA) outbreak sources. However, many older buildings continue to have sanitary facilities in high-risk departments such as the ICU. We present two simultaneous prolonged multi-drug-resistant (MDR) PA outbreaks detected at the ICU of a pulmonology hospital, which were resolved by whole-genome sequencing (WGS).
Methods
Outbreak management and investigations were initiated in August 2019 after detecting two patients with nosocomial VIM-2-positive MDR PA. The investigations involved weekly patient screenings for four months and extensive environmental sampling for 15 months. All patient and environmental isolates were collected and analysed by WGS.
Results
From April to September 2019, we identified 10 patients with nosocomial MDR PA, including five VIM-2-positive strains. VIM-2-positive strains were also detected in nine sink drains, two toilets, and a cleaning bucket. WGS revealed that of 16 VIM-2-positive isolates, 14 were ST111 that carried qacE, or qacEΔ1 genes, whereas 13 isolates clustered (difference of ≤11 alleles by cgMLST). OXA-2 (two toilets), and OXA-2, OXA-74, PER-1 (two patients, three toilets) qacEΔ1-positive ST235 isolates dominated among VIM-2-negative isolates. The remaining seven PA strains were ST17, ST233, ST273, ST309 and ST446. Outbreak containment was achieved by replacing U-bends, and cleaning buckets, and switching from quaternary ammonium compounds (QUATs) to oxygen-releasing disinfectant products.
Conclusion
Comprehension and management of two simultaneous MDR PA outbreaks involving the high-risk strains ST111 and ST235 were facilitated by precise control due to identification of different outbreak sources per strain, and by the in-silico detection of high-level QUATs resistance in all isolates
Nanosilver/DCOIT-containing surface coating effectively and constantly reduces microbial load in emergency room surfaces
Background
Colonization of near-patient surfaces in hospitals plays an important role as a source of healthcare-associated infections. Routine disinfection methods only result in short-term elimination of pathogens.
Aim
To investigate the efficiency of a newly developed antimicrobial coating containing nanosilver in long-term reduction of bacterial burden in hospital surfaces to close the gap between routine disinfection cycles.
Methods
In this prospective, double-blinded trial, frequently touched surfaces of a routinely used treatment room in an emergency unit of a level-I hospital were treated with a surface coating (nanosilver/DCOIT-coated surface, NCS) containing nanosilver particles and another organic biocidal agent (4,5-dichloro-2-octyl-4-isothiazolin-3-one, DCOIT), whereas surfaces of another room were treated with a coating missing both the nanosilver- and DCOIT-containing ingredient and served as control. Bacterial contamination of the surfaces was examined using contact plates and liquid-based swabs daily for a total trial duration of 90 days. After incubation, total microbial counts and species were assessed.
Findings
In a total of 2880 antimicrobial samples, a significant reduction of the overall bacterial load was observed in the NCS room (median: 0.31 cfu/cm2; interquartile range: 0.00–1.13) compared with the control coated surfaces (0.69 cfu/cm2; 0.06–2.00; P 5 cfu/cm2) by 60% (odds ratio 0.38, P < 0.001). No significant difference in species distribution was detected between NCS and control group.
Conclusion
Nanosilver-/DCOIT-containing surface coating has shown efficiency for sustainable reduction of bacterial load of frequently touched surfaces in a clinical setting
Signal transduction controls heterogeneous NF-κB dynamics and target gene expression through cytokine-specific refractory states
Cells respond dynamically to pulsatile cytokine stimulation. Here we report that single, or well-spaced pulses of TNFα (>100 min apart) give a high probability of NF-κB activation. However, fewer cells respond to shorter pulse intervals (<100 min) suggesting a heterogeneous refractory state. This refractory state is established in the signal transduction network downstream of TNFR and upstream of IKK, and depends on the level of the NF-κB system negative feedback protein A20. If a second pulse within the refractory phase is IL-1β instead of TNFα, all of the cells respond. This suggests a mechanism by which two cytokines can synergistically activate an inflammatory response. Gene expression analyses show strong correlation between the cellular dynamic response and NF-κB-dependent target gene activation. These data suggest that refractory states in the NF-κB system constitute an inherent design motif of the inflammatory response and we suggest that this may avoid harmful homogenous cellular activation
Pomalidomide mitigates neuronal loss, neuroinflammation, and behavioral impairments induced by traumatic brain injury in rat
Deep-water Stromatolites and Frutexites Maslov from the Early and Middle Jurassic of S-Germany and Austria
Despite extensive discussions during the last 20 years stromatolites are still used by many geologists as unequivocal indicators of very shallow-water conditions. We investigated four stratigraphic units from the Lower and Middle Jurassic of southern Germany (Posidonien-Schiefer, Amaltheen-Ton) and of the Northern Calcareous Alps (Adneter Kalk, Klauskalk), which were formerly interpreted as shallow marine sediments by some authors due to the occurrence of stromatolites. Our interpretations of the macro-, micro- and ultrafacies of these sediments are not compatible with shallow-water settings. We therefore propose a deep-marine, aphotic origin of these stromatolites.
Former interpretations of the Posidonien-Schiefer as a shallow-water deposit are mainly based on the occurrence of stromatolites. We favour the model of a temporarily stagnant, deep, aphotic basin for these planktonrich sediments. Particles resembling ooids, but lying within mudstones cannot be taken as evidence for shallow agitated water. They either formed within the mud or are allochthonous.
The deep-water setting of the red limestone of the Alpine Early and Middle Jurassic is indicated by a lack of platform-typical components like coated grains and phototrophic benthos and by shells of plankton and nekton forming a major part of the sediment. Stromatolites occur on the steep slope of a drowned Rhaetian reef with an estimated relief of 50–100 m and immediately below and within radiolarian limestones, deposited below the aragonite compensation depth (ACD).
The aphotic stromatolites show some morphological differences to their shallow water counterparts. In all of our sections they occurred during intervals of reduced sedimentation. They form only thin horizons and probably grew very slowly. Mineralizations by Fe−Mn oxides and phosphate are very common. The presence of a microbial film is evident from binding of sedimentary particles, but the nature of the microbes is not known. Growth habits within the very distinct environments of red limestone and black shales show some common features, but also clear differences.
The microproblematicum Frutexites Maslov is a very common component in deep-water stromatolites, but may also itself form small crusts or dendrolites. It occurs in two different forms. Opaque, slender forms with indistinct outlines probably grew within the weakly lithified sediment. Thicker, transparent forms with well defined outlines are found in cavities and probably also grew on the seafloor. Well preserved specimens display an internal fabric of radially arranged fibres of Fe−Mn oxides and calcite. It is suggested that calcite or aragonite were one original mineralogy ofFrutexites, which was later replaced by Fe−Mn oxides or phosphate.
It is not certain whether Frutexites is an organic, biomineralized structure or an inorganic mineralization, but the variable mineralogy and growth forms in different environments point to an organic origin. But even if organic, the occurrence in cryptic habitats and negative phototactic growth-directions make it clear that Frutexites was not phototrophi
Shallow burial diagenesis of skeletal carbonates: selective loss of aragonite shell material (Miocene to Recent, Queensland Plateau and Queensland Trough, NE Australia) - implications for shallow cool-water carbonates
In burial environments, carbonate sediments undergo mineralogical stabilization and increasing lithification with depth. As yet, however, little knowledge exists with respect to the corresponding effects on fossil preservation and taphonomic modification of the original sediment composition. Countings of particles (>63 μm) in Miocene to Recent periplatform sediments (ODP Leg 133, NE Australia) exhibit a clear trend of reduction of skeletal aragonite downcore. Low- and high-Mg-calcite grains occur in a continuous order of magnitude over the studied interval (<600 m sub-bottom depth). Original microtextures are retained in high-Mg-calcite biota, although converted to low-Mg-calcite. Thus, the conversion to low-Mg-calcite appears to occur without introducing a significant quantitative bias. Aragonite skeletons (pelagic gastropods), however, exhibit a successive exposure of deeper crystal layers and a chalky preservation with burial depth, which we interpret to result from dissolution. Hints for the originally more numerous existence of aragonite biota exist in soft sediments and chalks by the presence of internal moulds, shells replaced by microspar, and mouldic porosity in early cemented hardgrounds. In deep sections barren of aragonite, the number of casts and replaced shells remains unchanged and is insignificant as compared to aragonitic biota probably originally present within the sediment (<2% in ooze/chalk vs. 30–50% of grains in modern periplatform sediments). Therefore, palaeontological information must be significantly biased through selective removal of aragonite. Rates of preservation and destruction depend on external factors during sediment accretion (sedimentation rates, clay content, total organic carbon content) and rates of fluid flow within the sediment. These observations are relevant with respect to the diagenetic potential and patterns of fossil preservation in little cemented calcitic cool-water carbonates, because they may originally have contained more aragonite biota as important constituents of an ecosystem than is commonly suspected, and calcite/aragonite ratios in ancient carbonate sediments may not necessarily reflect original input signals (climate or sea level)
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An unusual Pocillopora reef from the Late Miocene of Hispaniola
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