MTT assay has been applied widely in stimulation and inhibition tests for adherent cells. However, reading step in regular MTT assays requires medium removal to dissolve formazan by absolute solvents ...results are usually affected by incomplete formazan dissolution and protein precipitation in diluted solvents. Therefore, most of current MTT assay procedures have difficulties in application on suspension cell lines. In this study, we demonstrated a modified MTT assay in which formazan dissolution method was improved by using the combination of DMSO and SDS-lysis solution. Importantly, the modified MTT assay did not require medium removal, thus it can be applicable for both suspension and adherent cell lines. We also verified that the modified MTT procedure could be effectively applied in bioactivity assays such as cancer cell inhibition and fibroblast stimulation assays. Besides the ease of use, our data regarding nonlinear regression model fitting, data variation, and separation clearly demonstrated that the sensitivity, stability and precision of modified assay were higher than those of common MTT procedures using isopropanol or DMSO as solvents. This study indicated that the modification described here can broaden the MTT assay application on suspension cell lines and also simplify the MTT protocol on adherent cell lines.
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•This study demonstrated a modified MTT assay can be be applied in bioassays on both adherent cells and suspension cells.•Modified MTT assay coulde be applied on cell cullture without medium removal by which could reduce variety of data.•Modified MTT procedure improved sensitivity and stability of bioassay results.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We use the Low Frequency Array (LOFAR) to probe the dynamics of the stepping process of negatively charged plasma channels (negative leaders) in a lightning discharge. We observe that at each step of ...a leader, multiple pulses of vhf (30-80 MHz) radiation are emitted in short-duration bursts (<10 μs). This is evidence for streamer formation during corona flashes that occur with each leader step, which has not been observed before in natural lightning and it could help explain x-ray emission from lightning leaders, as x rays from laboratory leaders tend to be associated with corona flashes. Surprisingly, we find that the stepping length is very similar to what was observed near the ground, however with a stepping time that is considerably larger, which as yet is not understood. These results will help to improve lightning propagation models, and eventually lightning protection models.
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We report here on a novel analysis of the complete set of four Stokes parameters that uniquely determine the linear and/or circular polarization of the radio signal for an extensive air shower. The ...observed dependency of the circular polarization on azimuth angle and distance to the shower axis is a clear signature of the interfering contributions from two different radiation mechanisms, a main contribution due to a geomagnetically-induced transverse current and a secondary component due to the build-up of excess charge at the shower front. The data, as measured at LOFAR, agree very well with a calculation from first principles. This opens the possibility to use circular polarization as an investigative tool in the analysis of air shower structure, such as for the determination of atmospheric electric fields.
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In recent years, the tensegrity structures have been studied and applied extensively in the engineering field because of their unique topology, shape, and stability. An effective force ...density-informed neural network (FDINN) approach for performing a robust force finding procedure is constructed in this paper by utilizing a fully connected neural network. The design variables as the input values are first transformed into a parameterized neural network, then these neural network’s parameters are updated in the learning process by an error design loss function via backpropagation and standard optimizer to obtain an optimal self-stress configuration as the output values. By using FDINN, this approach is effectively applied for multiple tensegrity models without depending on the amount of data samples and considering the structural symmetric property. The stability of tensegrity structure is investigated by checking tangent stiffness matrix. Various numerical examples are thoroughly carried out to validate for the effectiveness of the present approach.
•A powerful and effective numerical approach for finding initial force densities.•Using force density-informed neural network to obtain the feasible prestress design.•Save computational cost without using other techniques and metaheuristic algorithms.•Applying for several regular and irregular tensegrity structures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Using electron paramagnetic resonance (EPR), energy levels of the carbon vacancy (V(C)) in 4H-SiC and its negative-U properties have been determined. Combining EPR and deep-level transient ...spectroscopy we show that the two most common defects in as-grown 4H-SiC--the Z(1/2) lifetime-limiting defect and the EH(7) deep defect--are related to the double acceptor (2-|0) and single donor (0|+) levels of V(C), respectively.
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The radio intensity and polarization footprint of a cosmic-ray induced extensive air shower is determined by the time-dependent structure of the current distribution residing in the plasma cloud at ...the shower front. In turn, the time dependence of the integrated charge-current distribution in the plasma cloud, the longitudinal shower structure, is determined by interesting physics which one would like to extract, such as the location and multiplicity of the primary cosmic-ray collision or the values of electric fields in the atmosphere during thunderstorms. To extract the structure of a shower from its footprint requires solving a complicated inverse problem. For this purpose we have developed a code that semianalytically calculates the radio footprint of an extensive air shower given an arbitrary longitudinal structure. This code can be used in an optimization procedure to extract the optimal longitudinal shower structure given a radio footprint. On the basis of air-shower universality we propose a simple parametrization of the structure of the plasma cloud. This parametrization is based on the results of Monte Carlo shower simulations. Deriving the parametrization also teaches which aspects of the plasma cloud are important for understanding the features seen in the radio-emission footprint. The calculated radio footprints are compared with microscopic CoREAS simulations.
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The potential of green nanomaterials for environmental and agricultural fields is emerging due to their biocompatible, eco-friendly, and cost-effective performance. We report the use of Canna indica ...flowers extract as new capping and stabilizing source to bio-fabricate ZnO nanoparticles (ZnO NPs for dyes removal, seed germination. ZnO NPs was biosynthesized by ultrasound-assisted alkaline-free route to reach the critical green strategy. The physicochemical findings of ZnO revealed small crystallite size (27.82 nm), sufficient band-gap energy (3.08 eV), and diverse functional groups. Minimum‑run resolution IV approach found the most pivotal factors influencing on removal of Coomassie Brilliant Blue G-250. Uptake studies pointed out that pseudo second-order, and Langmuir were the best fitted models. Dye molecules behaved monolayer adsorption on ZnO surface layers, and controlled by chemisorption. Natural solar light was used as effective source for photocatalytic degradation of methylene blue (94.23% of removal and 31.09 mg/g of uptake capacity). Compared with H2O and ZnSO4, ZnO NPs positively affected the growth of shoot and root lengths (10.2–27.8%) of bean seedlings in most cases. ZnO acts an agrochemical for boosting weight gain, and germination ratio. This study may be promising for developing the recyclable, multifunctional ZnO nanoparticles for environmental and agricultural applications.
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•ZnO nanoparticles were biosynthesized from Canna indica L. flowers.•Minimum–run resolution IV was used to screen and optimize the adsorption parameters.•Photodegradation of methylene blue was conducted under solar light illumination.•ZnO nanoparticles boosted shoot and root lengths of green and red bean seedlings.•Good recyclability and high removal efficiency were obtained.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background. Tuberculous meningitis (TBM) is the most devastating form of tuberculosis, yet very little is known about the pathophysiology. We hypothesized that the genotype of leukotriene A₄ ...hydrolase (encode by LTA4H), which determines inflammatory eicosanoid expression, influences intracerebral inflammation, and predicts survival from TBM. Methods. We characterized the pretreatment clinical and intracerebral inflammatory phenotype and 9-month survival of 764 adults with TBM. All were genotyped for single-nucleotide polymorphism rs17525495, and inflammatory phenotype was defined by cerebrospinal fluid (CSF) leukocyte and cytokine concentrations. Results. LTA4H genotype predicted survival of human immunodeficiency virus (HIV)=uninfected patients, with TT-genotype patients significantly more likely to survive TBM than CC-genotype patients, according to Cox regression analysis (univariate P = .040 and multivariable P = .037). HIV-uninfected, TT-genotype patients had high CSF proinflammatory cytokine concentrations, with intermediate and lower concentrations in those with CT and CC genotypes. Increased CSF cytokine concentrations correlated with more-severe disease, but patients with low CSF leukocytes and cytokine concentrations were more likely to die from TBM, HIV infection independently predicted death due to TBM (hazard ratio, 3.94; 95% confidence interval, 2.79-5.56) and was associated with globally increased CSF cytokine concentrations, independent of LTA4H genotype. Conclusions. LTA4H genotype and HIV infection influence pretreatment inflammatory phenotype and survival from TBM. LTA4H genotype may predict adjunctive corticosteroid responsiveness in HIV-uninfected individuals.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
The antibacterial activity of a Cinnamomum cassia essential oil (EO) and of its main component trans‐cinnamaldehyde (90% w/w) was examined against five Listeria monocytogenes strains. The minimal ...inhibitory concentrations (MICs) of C. cassia EO against the five L. monocytogenes strains were identical (250 µg ml−1), while the minimal bactericidal concentrations (MBCs) ranged between 800 and 1200 µg ml−1. In order to study if this EO and trans‐cinnamaldehyde altered the five strains at the membrane level, fluorescence anisotropy of 1,6‐diphenyl‐1,3,5‐hexatriene (DPH) was measured in presence of different concentrations (1/2MIC, MIC, 2MIC) of these antibacterial agents. A concentration‐dependent increase of fluorescence anisotropy of DPH in their presence reflecting a rigidification of the membrane was observed for the five strains. This modification of the membrane fluidity was associated with a perturbation of the selective membrane permeability, as a perturbation of the gradient between intracellular and extracellular pH was also observed.
Significance and Impact of the Study: This study aimed to characterize the difference of sensitivity and mode of action of trans‐cinnamaldehyde and Cinnamomum cassia EO among different strains of Listeria monocytogenes. The strains were of different origin and serovar. Interstrain differences of sensitivity were limited. These molecules are therefore reliable food preservative against this pathogen. Also, the major component of this EO, trans‐cinnamaldehyde, had the same MIC as the EO, indicating that the 12 other components had minor effect. The mode of action was also almost identical whatever the strain, with cytoplasmic membrane fluidity and intracellular pH perturbation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
The common phenomenon of lightning still harbors many secrets such as what are the conditions for lightning initiation and what is driving the discharge to propagate over several tens of ...kilometers through the atmosphere forming conducting ionized channels called leaders. Since lightning is an electric discharge phenomenon, there are positively and negatively charged leaders. In this work we report on measurements made with the LOFAR radio telescope, an instrument primarily build for radio-astronomy observations. It is observed that a negative leader rather suddenly changes, for a few milliseconds, into a mode where it radiates 100 times more VHF power than typical negative leaders after which it spawns a large number of more typical negative leaders. This mode occurs during the initial stage, soon after initiation, of all lightning flashes we have mapped (about 25). For some flashes this mode occurs also well after initiation and we show one case where it is triggered twice, some 100 ms apart. We postulate that this is indicative of a small (order of 5 km
$$^2$$
2
) high charge pocket. Lightning thus appears to be initiated exclusively in the vicinity of such a small but dense charge pocket.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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