604 research outputs found

    Three soil bacterial communities from an archaeological excavation site of an ancient coal mine near Bennstedt (Germany) characterized by 16S r-RNA sequencing

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    This metagenomics investigation of three closely adjacent sampling sites from an archaeological excavation of a pre-industrial coal mining exploration shaft provides detailed information on the composition of the local soil bacterial communities. The observed significant differences between the samples, reflected in the 16S r-RNA analyses, were consistent with the archaeologically observed situation distinguishing the coal seam, the rapidly deposited bright sediment inside an exploration shaft, and the topsoil sediment. In general, the soils were characterized by a dominance of Proteobacteria , Actinobacteria , Acidobacteria , and Archaea , whereas the coal seam was characterized by the highest proportion of Proteobacteria ; the topsoil was characterized by very high proportions of Archaea —in particular, Nitrosotaleaceae —and Acidobacteria, mainly of Subgroup 2. Interestingly, the samples of the fast-deposited bright sediment showed a rank function of OTU abundances with disproportional values in the lower abundance range. This could be interpreted as a reflection of the rapid redeposition of soil material during the refilling of the exploration shaft in the composition of the soil bacterial community. This interpretation is supported by the observation of a comparatively high proportion of reads relating to bacteria known to be alkaliphilic in this soil material. In summary, these investigations confirm that metagenomic analyses of soil material from archaeological excavations can provide valuable information about the local soil bacterial communities and the historical human impacts on them

    Formation and fluorimetric characterization of micelles in a micro-flow through system with static micro mixer

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    The formation and behaviour of micelles of sodium dodecylsulfate in water byuse of a static micro mixer were studied. Trisbipyridylruthenium(II) was applied asindicator dye, 9-methylanthracene was used for fluorescence quenching. All experimentswere carried out by a micro fluid arrangement with three syringe pumps, a 2 1 two-stepstatic micro mixer (IPHT Jena) and a on-line micro fluorimetry including a luminescencediode for excitation, a blue glass filter (BG 7, Linos), two edge filters (RG 630, Linos) anda photo counting module (MP 900, Perkin Elmer). It was possible to measure thefluorescence inside the PTFE tube (inner diameter 0.5 mm) directly. A linear dependenceof fluorescence intensity from dye concentration was observed in absence of quencher andsurfactant as expected. An aggregation number of about 62 was found in the flow raterange between 300 and 800 μL/min. The fluorescence intensity increases slightly, butsignificant with increasing flow rate, if no quencher is present. In the presence of quencher,the fluorescence intensity decreases with decreasing surfactant concentration and withenhanced flow rate. The strength of the flow rate effect on the fluorescence increases withdecreasing surfactant concentration. The size of micelles was determined in micro channelsby the micro fluorimetric method in analogy to the conventional system. The micellesextract the quencher from the solution and lower, this way, the quenching effect. The sizeof micelles was estimated and it could be shown, that the flow rate has only low effect onthe aggregation number at the investigated flow rates. The effect of flow rate andsurfactant concentration on the fluorescence in the presence of quencher was interpreted asa shift in the micelle concentration due to the shear forces. It is expected, that thefluorescence intensity is lowered, if more quencher molecules are molecular disperse distributed inside the solution. Obviously, the lowered fluorescence intensity at higher flow rates suggests a reduction of the micelle density causing an increase of quencher concentration outside the micelles

    Global Retrievals of Solar-Induced Chlorophyll Fluorescence at Red Wavelengths With TROPOMI

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    Observations of solar‐induced chlorophyll a fluorescence (SIF) from spaceborne spectrometers can advance our understanding of terrestrial and aquatic carbon cycles. Here we present the first global retrievals of SIF at red wavelengths from the TROPOspheric Monitoring Instrument (TROPOMI). Despite the weak signal level, considerable uncertainties, and subtle measurement artifacts, spatial patterns and magnitudes agree with independent data sets. Over land, spatial patterns of our red SIF estimates covary with the far‐red SIF data. Red SIF over the ocean is highly consistent with the normalized fluorescence line height (nFLH) inferred from measurements of the MODerate resolution Imaging Spectroradiometer (MODIS), even when comparing single days and fine spatial scales. Major advantages of our Fraunhofer line‐based SIF retrievals include the capability to sense SIF through optically thin cloud/aerosol layers and an insensitivity to ocean color. This opens up new avenues for studying ocean biogeochemistry from space

    Global Retrievals of Solar-Induced Chlorophyll Fluorescence at Red Wavelengths With TROPOMI

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    Observations of solar‐induced chlorophyll a fluorescence (SIF) from spaceborne spectrometers can advance our understanding of terrestrial and aquatic carbon cycles. Here we present the first global retrievals of SIF at red wavelengths from the TROPOspheric Monitoring Instrument (TROPOMI). Despite the weak signal level, considerable uncertainties, and subtle measurement artifacts, spatial patterns and magnitudes agree with independent data sets. Over land, spatial patterns of our red SIF estimates covary with the far‐red SIF data. Red SIF over the ocean is highly consistent with the normalized fluorescence line height (nFLH) inferred from measurements of the MODerate resolution Imaging Spectroradiometer (MODIS), even when comparing single days and fine spatial scales. Major advantages of our Fraunhofer line‐based SIF retrievals include the capability to sense SIF through optically thin cloud/aerosol layers and an insensitivity to ocean color. This opens up new avenues for studying ocean biogeochemistry from space

    Formation of Star-Like and Core-Shell AuAg Nanoparticles during Two- and Three-Step Preparation in Batch and in Microfluidic Systems

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    Regular dendrit-like metal nanoparticles and core-shell nanoparticles were formed by the reduction of mixtures of tetrachloroaurate and silver nitrate solutions with ascorbic acid at room temperature in two- and three-step procedures. The formation of these particles was found in batch experiments as well as in micro flow-through processes using static micromixers. The characteristic diameters of 4-branched star particles were in the range between 60 and 100 nm. The typical particles consist of four metal cores which are embedded in a common shell. Additionally, particles with five and more metallic cores were formed, to some extent, and aggregates of the 4-branched particles also were formed. Larger aggregates and network-like structures of connected star particles were formed after sedimentation. The properties of the formed particles are dependent on the educt concentrations as well as on the order of mixing steps and on the time interval between them. Obviously, the relation of nucleation and particle growth in relation to the concentrations of metal ions determines the composition and the properties of formed nanoparticles. So, star-like particles are observed in case of nucleation of Au in absence of silver ions but with silver deposition after short nucleation time. Spherical core shell particles are formed in case of silver salt addition after complete reduction of tetrachloroaurate in flow-through experiments with sufficient residence time between both mixing steps. Polymer layers are always found in the form of a second outer shell even if the polymer solutions are added in an early stage of particle formation

    Serum insulin-like growth factor-1 and its binding protein-7: potential novel biomarkers for heart failure with preserved ejection fraction

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    BACKGROUND: Insulin-like growth factor binding protein-7 (IGFBP-7) modulates the biological activities of insulin-like growth factor-1 (IGF-1). Previous studies demonstrated the prognostic value of IGFBP-7 and IGF-1 among patients with systolic heart failure (HF). This study aimed to evaluate the IGF1/IGFBP-7 axis in HF patients with preserved ejection fraction (HFpEF). METHODS: Serum IGF-1 and IGFBP-7 levels were measured in 300 eligible consecutive patients who underwent comprehensive cardiac assessment. Patients were categorized into 3 groups including controls with normal diastolic function (n = 55), asymptomatic left ventricular diastolic dysfunction (LVDD, n = 168) and HFpEF (n = 77). RESULTS: IGFBP-7 serum levels showed a significant graded increase from controls to LVDD to HFpEF (median 50.30 [43.1-55.3] vs. 54.40 [48.15-63.40] vs. 61.9 [51.6-69.7], respectively, P < 0.001), whereas IGF-1 levels showed a graded decline from controls to LVDD to HFpEF (120.0 [100.8-144.0] vs. 112.3 [88.8-137.1] vs. 99.5 [72.2-124.4], p < 0.001). The IGFBP-7/IGF-1 ratio increased from controls to LVDD to HFpEF (0.43 [0.33-0.56] vs. 0.48 [0.38-0.66] vs. 0.68 [0.55-0.88], p < 0.001). Patents with IGFB-7/IGF1 ratios above the median demonstrated significantly higher left atrial volume index, E/E’ ratio, and NT-proBNP levels (all P ≤ 0.02). CONCLUSION: In conclusion, this hypothesis-generating pilot study suggests the IGFBP-7/IGF-1 axis correlates with diastolic function and may serve as a novel biomarker in patients with HFpEF. A rise in IGFBP-7 or the IGFBP-7/IGF-1 ratio may reflect worsening diastolic function, adverse cardiac remodeling, and metabolic derangement

    Small sharp exostosis tip in solitary osteochondroma causing intermittent knee pain due to pseudoaneurysm

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    Background: Complications of solitary or multiple osteochondromas are rare but have been reported in recent literature. Most reported complications arose in patients with multiple and/or sizable osteochondromas. Case presentation: A 22-year-old, female, Caucasian patient with obesity presented with intermittent knee pain and hematoma of the right calf. The MRI depicted a small, sharp exostosis tip of the dorsal distal femur with a surrounding soft-tissue mass. After profuse bleeding occurred during biopsy of the soft tissue mass, angiography revealed a pseudoaneurysm of the right popliteal artery. In a second-stage surgery the exostosis tip and pseudoaneurysm were resected. Conclusion: Complications can also arise in small, seemingly harmless osteochondromas. Surgical resection should be considered as a preventive measure when exostoses form sharp tips close to neurovascular structures regardless of total osteochondroma size.<br

    Chip technology for fast serological determination of Salmonella serovars

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    The nucleotide sequence encoding the Salmonella plasmid virulence factor D (SpvD) was determined in 17 Salmonella strains that were different in O and H antigen patterns, animal host and geographical origin, and year of isolation. Nucleotide sequence comparison revealed the existence of at least nine spvD alleles resulting in 8 SpvD protein variants although the nucleotide sequences were highly similar (identity 98.8- 100 %)

    A fundamental limit for integrated atom optics with Bose-Einstein condensates

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    The dynamical response of an atomic Bose-Einstein condensate manipulated by an integrated atom optics device such as a microtrap or a microfabricated waveguide is studied. We show that when the miniaturization of the device enforces a sufficiently high condensate density, three-body interactions lead to a spatial modulational instability that results in a fundamental limit on the coherent manipulation of Bose-Einstein condensates.Comment: 6 pages, 3 figure

    Emerging applications of fluorescence spectroscopy in medical microbiology field

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    There are many diagnostic techniques and methods available for diagnosis of medically important microorganisms like bacteria, viruses, fungi and parasites. But, almost all these techniques and methods have some limitations or inconvenience. Most of these techniques are laborious, time consuming and with chances of false positive or false negative results. It warrants the need of a diagnostic technique which can overcome these limitations and problems. At present, there is emerging trend to use Fluorescence spectroscopy as a diagnostic as well as research tool in many fields of medical sciences. Here, we will critically discuss research studies which propose that Fluorescence spectroscopy may be an excellent diagnostic as well as excellent research tool in medical microbiology field with high sensitivity and specificity
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