341 research outputs found
Large Scale Bacterial Colony Screening of Diversified FRET Biosensors
Biosensors based on Forster Resonance Energy Transfer (FRET) between fluorescent protein mutants have started to revolutionize physiology and biochemistry. However, many types of FRET biosensors show relatively small FRET changes, making measurements with these probes challenging when used under sub-optimal experimental conditions. Thus, a major effort in the field currently lies in designing new optimization strategies for these types of sensors. Here we describe procedures for optimizing FRET changes by large scale screening of mutant biosensor libraries in bacterial colonies. We describe optimization of biosensor expression, permeabilization of bacteria, software tools for analysis, and screening conditions. The procedures reported here may help in improving FRET changes in multiple suitable classes of biosensors
Toward On-Line Slag Composition Analysis: Optical Emissions from Laboratory Electric Arc
We acknowledge the support of Research Fund for Coal and Steel under grant agreement No. 709923, Academy of Finland for Genome of Steel grant No. 311934, Business Finland for Grant No. 4478/31/2019, Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.Electric arc furnaces and ladle furnaces have an important role in the future of steelmaking where CO 2 emissions have to be mitigated to an acceptable level. One way to address this goal is to optimize and improve the current practices by adjusting the chemistry and reactions with material additions or gas injections. These procedures would greatly benefit from on-line slag composition analysis. Since the electric arcs radiate throughout the melting, optical emission spectroscopy is a potential method for such analysis. In this study, optical emissions from the electric arc are measured in a laboratory environment. Dozens of atomic emission lines were correlated with Cr 2O 3, Fe 2O 3, Al 2O 3, SiO 2, MnO, MgO, CaO, CaF 2, V 2O 5, and Ni content of the slag together with correlation between CaF 2 and molecular optical emission bands of CaF. Optimal spectral resolution for industrial applications was deducted to be between 0.022 and 0.179 nm. © 2021, The Author(s). --//-- Published under the CC BY license.Academy of Finland for Genome of Steel 311934, 4478/31/2019; Research Fund for Coal and Steel 709923; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2
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Large area quantitative analysis of nanostructured thin-films
Proposed and verified method offers an unique quantitative large scale nanostructures' evaluation.This is the accepted manuscript. The final version is available at http://pubs.rsc.org/en/Content/ArticleLanding/2015/RA/c4ra16018e#!divAbstract
Production and properties of ferrite-rich CSAB cement from metallurgical industry residues
Blast furnace slag from the steel industry is commercially utilized as a cement replacement material without major processing requirements; however, there are many unutilized steel production slags which differ considerably from the blast furnace slag in chemical and physical properties. In this study, calcium sulfoaluminate belite (CSAB) cement clinkers were produced using generally unutilized metallurgical industry residues: AOD (Argon Oxygen Decarburisation) slag from stainless steel production, Fe slag from zinc production, and fayalitic slag from nickel production. CSAB clinker with a target composition of ye'elimite-belite-ferrite was produced by firing raw materials at 1300 °C. The phase composition of the produced clinkers was identified using quantitative XRD analyses, and the chemical composition of the clinker phases produced was established using FESEM-EDS and mechanical properties were tested through compressive strength test. It is demonstrated that these metallurgical residues can be used successfully as alternative raw materials for the production of CSAB cement that can be used for special applications. In addition, it is shown that the available quantities of these side-streams are enough for significant replacement of virgin raw materials used in cement production
Alternative raw materials for the production of calcium sulfoaluminate cement : ladle slag and phosphogypsum
Calcium sulfoaluminate belite (CSAB) cement clinkers were produced using two industrial by-products: ladle slag and
phosphogypsum. The phase composition of the produced clinkers was identified using quantitative XRD analyses, and the chemical composition of the clinker phases produced from phosphogypsum was established using FESEM-EDS. We demonstrate that ladle slag and phosphogypsum can be used as alternative raw materials for the production of CSAB cement. We also show that phosphorous from the phosphogypsum can be incorporated into the larnite crystal structure. The mechanical properties of the hydrated/hardened cement are also presented and are comparable with those produced from reagent-grade materials
Lattice-Boltzmann hydrodynamics of anisotropic active matter
A plethora of active matter models exist that describe the behavior of
self-propelled particles (or swimmers), both with and without hydrodynamics.
However, there are few studies that consider shape-anisotropic swimmers and
include hydrodynamic interactions. Here, we introduce a simple method to
simulate self-propelled colloids interacting hydrodynamically in a viscous
medium using the lattice-Boltzmann technique. Our model is based on
raspberry-type viscous coupling and a force/counter-force formalism which
ensures that the system is force free. We consider several anisotropic shapes
and characterize their hydrodynamic multipolar flow field. We demonstrate that
shape-anisotropy can lead to the presence of a strong quadrupole and octupole
moments, in addition to the principle dipole moment. The ability to simulate
and characterize these higher-order moments will prove crucial for
understanding the behavior of model swimmers in confining geometries.Comment: 11 pages, 3 figures, 3 table
Biologically active Phytophthora mating hormone prepared by catalytic asymmetric total synthesis
A Phytophthora mating hormone with an array of 1,5-stereogenic centers has been synthesized by using our recently developed methodology of catalytic enantioselective conjugate addition of Grignard reagents. We applied this methodology in a diastereo- and enantioselective iterative route and obtained two of the 16 possible stereoisomers of Phytophthora hormone α1. These synthetic stereoisomers induced the formation of sexual spores (oospores) in A2 mating type strains of three heterothallic Phytophthora species, P. infestans, P. capsici, and P. nicotianae but not in A1 mating type strains. The response was concentration-dependent, and the oospores were viable. These results demonstrate that the biological activity of the synthetic hormone resembles that of the natural hormone α1. Mating hormones are essential components in the sexual life cycle of a variety of organisms. For plant pathogens like Phytophthora, sexual reproduction is important as a source of genetic variation. Moreover, the thick-walled oospores are the most durable propagules that can survive harsh environmental conditions. Sexual reproduction can thus greatly affect disease epidemics. The availability of synthetic compounds mimicking the activity of Phytophthora mating hormone will be instrumental for further unravelling sexual reproduction in this important group of plant pathogens.
Ferritic calcium sulfoaluminate belite cement from metallurgical industry residues and phosphogypsum : clinker production, scale-up, and microstructural characterisation
The production of ferrite-rich calcium sulfoaluminate belite (CSABF) cement clinker, also containing MgO, from ladle slag, Fe-slag, and phosphogypsum was translated from a lab-scale to a pilot demonstration in a 7-metre kiln at 1260 °C. An account of the pilot trials/manufacturing is presented, and the process was robust. Laboratory tests prior to scale-up showed that gehlenite formation can be inhibited in the CSABF clinker by adding excess CaO in the raw meal; however, this reduces the amount of iron (Fe) that can be incorporated into ye'elimite and leads to higher ferrite (C6AF2) content. Detailed microstructural analyses were performed on the clinker to reveal the clinker composition as well as the partition of the minor elements. Different ferrite phases with varying amounts of titanium and iron are distinguished. Eighty-five percent of the clinker raw meal was comprised of side-stream materials and the clinker produced in the kiln had chemical raw-material CO2 emissions 90% lower than that of Portland cement made from virgin raw materials. These results can have a significant impact in regions with a prospering metallurgical industry, enabling industrial decarbonisation and resource efficiency
Neutrophils promote venular thrombosis by shaping the rheological environment for platelet aggregation
In advanced inflammatory disease, microvascular thrombosis leads to the interruption of blood supply and provokes ischemic tissue injury. Recently, intravascularly adherent leukocytes have been reported to shape the blood flow in their immediate vascular environment. Whether these rheological effects are relevant for microvascular thrombogenesis remains elusive. Employing multi-channel in vivo microscopy, analyses in microfluidic devices, and computational modeling, we identified a previously unanticipated role of leukocytes for microvascular clot formation in inflamed tissue. For this purpose, neutrophils adhere at distinct sites in the microvasculature where these immune cells effectively promote thrombosis by shaping the rheological environment for platelet aggregation. In contrast to larger (lower-shear) vessels, this process in high-shear microvessels does not require fibrin generation or extracellular trap formation, but involves GPIb alpha-vWF and CD40-CD40L-dependent platelet interactions. Conversely, interference with these cellular interactions substantially compromises microvascular clotting. Thus, leukocytes shape the rheological environment in the inflamed venular microvasculature for platelet aggregation thereby effectively promoting the formation of blood clots. Targeting this specific crosstalk between the immune system and the hemostatic system might be instrumental for the prevention and treatment of microvascular thromboembolic pathologies, which are inaccessible to invasive revascularization strategies
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