475 research outputs found
Foraminifera as prey for benthic deposit feeders: Results of predator exclusion experiments
To assess the importance of predation on foraminifera, a meiofaunal enclosure with openings of 1 mm containing 30 l of azoic sand was placed in a subtidal flat at Link Port, Florida in February 1976. During March, April, May, and June 1976, 4 replicate samples were taken inside and outside the cage. Foraminiferal densities were significantly higher inside the cage indicating foraminiferal densities are higher in the absence of macrofaunal predators...
Identification of Cohesive Ends and Genes Encoding the Terminase of Phage 16-3
Cohesive ends of 16-3, a temperate phage of Rhizobium meliloti 41, have been identified as 10-base-long, 3′-protruding complementary G/C-rich sequences. terS and terL encode the two subunits of 16-3 terminase. Significant homologies were detected among the terminase subunits of phage 16-3 and other phages from various ecosystems
Species densities of macrobenthos associated with seagrass: A field experimental study of predation
Caging experiments in a wide variety of marine environments over a period of almost fifty years have produced dramatic density increases of macrobenthos in the absence of predators. This study utilized predator exclusion cages in seagrass areas of a subtropical estuary in east central Florida to determine if predicted increases in density would result...
Dimensionality constraints of light-induced rotation
We have studied the conditions of rotation induced by collimated light carrying no angular momentum. Objects of different shapes and optical properties were examined in the nontrivial case where the rotation axis is perpendicular to the direction of light propagation. This geometry offers important advantages for application as it fundamentally broadens the possible practical arrangements to be realised. We found that collimated light cannot drive permanent rotation of 2D or prism-like 3D objects (i.e., fixed cross-sectional profile along the rotation axis) in the case of fully reflective or fully transparent materials. Based on both geometrical optics simulations and theoretical analysis, we derived a general condition for rotation induced by collimated light carrying no angular momentum valid for any arrangement: Permanent rotation is not possible if the scattering interaction is two-dimensional and lossless. In contrast, light induced rotation can be sustained if partial absorption is present or the object has specific true 3D geometry. We designed, simulated, fabricated, and experimentally tested a microscopic rotor capable of rotation around an axis perpendicular to the illuminating light. (c) 2015 AIP Publishing LLC
Analysis of 3D filament structures in various magnetic configurations of the W7-X stellarator
Excimer Laser-produced Biodegradable Photopolymer Scaffolds Do Not Induce Immune Rejection In Vivo
Following our previous works of in-vitro tests, the biocompatibility of photopolymer scaffolds was tested against immune responses in vivo. Neither relevant immune reactions nor the rejection of implanted scaffolds was detected, being an essential step for in vivo implantation of excimer laser-prepared scaffolds. The scaffolds were fabricated by UV excimer laser photocuring at 308 nm. After two weeks of transplantation neither inflammatory response nor reactive immune activation was detected based on the chemokine and cytokine profile. As a sign of biodegradability of the scaf-folds, we detected macrophage infiltration and phagocytosis of the biopolymer at the site of implan-tation. Our results suggest that poly(propylene fumarate) (PPF): diethyl fumarate (DEF) (7 : 3 w/w) scaffolds have appropriate properties for in vivo applications
Excimer laser-produced biodegradable photopolymer scaffolds do not induce immune rejection in vivo - ResearchGate. Available from: http://www.researchgate.net/publication/268523447_Excimer_laser-produced_biodegradable_photopolymer_scaffolds_do_not_induce_immune_rejection_in_vivo [accessed Aug 17, 2015]
A quantitative metric for the comparative evaluation of optical clearing protocols for 3D multicellular spheroids
3D multicellular spheroids quickly emerged as in vitro models because they represent the in vivo tumor environment better than standard 2D cell cultures. However, with current microscopy technologies, it is difficult to visualize individual cells in the deeper layers of 3D samples mainly because of limited light penetration and scattering. To overcome this problem several optical clearing methods have been proposed but defining the most appropriate clearing approach is an open issue due to the lack of a gold standard metric. Here, we propose a guideline for 3D light microscopy imaging to achieve single-cell resolution. The guideline includes a validation experiment focusing on five optical clearing protocols. We review and compare seven quality metrics which quantitatively characterize the imaging quality of spheroids. As a test environment, we have created and shared a large 3D dataset including approximately hundred fluorescently stained and optically cleared spheroids. Based on the results we introduce the use of a novel quality metric as a promising method to serve as a gold standard, applicable to compare optical clearing protocols, and decide on the most suitable one for a particular experiment
Seasonal and spatial variations of saltmarsh benthic foraminiferal communities from North Norfolk, England
Time series foraminiferal data were obtained from samples collected from three sites at Brancaster Overy Staithe, Burnham Overy Staithe and Thornham on the North Norfolk coast over a 1-year period. At each collection point, six environmental variables—temperature, chlorophyll, sand, mud, pH and salinity—were also measured. The principle aim of this study was to examine the benthic foraminiferal fauna in regard to the temporal variability of foraminiferal abundance, seasonal trend, dominant species, species diversity and the impact of environmental variables on the foraminiferal communities in the top 1 cm of sediment over a 1-year time series. The foraminiferal assemblages at the three sites were dominated by three species: Haynesina germanica, Ammonia sp. and Elphidium williamsoni. Foraminiferal species showed considerable seasonal and temporal fluctuation throughout the year at the three investigated sites. The foraminiferal assemblage at the three low marsh zones showed a maximum abundance in autumn between September and November and a minimum abundance observed between July and August. There were two separate peaks in the abundance of Ammonia sp. and E. williamsoni, one in spring and another in autumn. In contrast, H. germanica showed a single peak in its abundance in autumn. A generalized additive modelling approach was used to explain the variation in the observed foraminiferal abundance and to estimate the significant impact of each of the environmental variables on living foraminiferal assemblages, with taxa abundance as the dependent variable. When included in the model as predictors, most of the environmental variables contributed little in explaining the observed variation in foraminiferal species abundance. However, the hypotheses for differences amongst sites, salinity and pH were significant and explained most of the variability in species relative abundance
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