For the first time, a rapid method was proposed to determine the susceptibility of
Escherichia coli
cells to antibiotics by the example of ampicillin by using a biological sensor based on a slot mode ...in an acoustic delay line. It has been established that an indicator of the antibiotic activity to microbial cells is the difference between the recorded sensor’s signal before and after exposure cells with antibiotic. The depth and frequency of the peaks of resonant absorption in the frequency dependence of the insertion loss of sensor varied after adding an antibiotic with different concentrations to the microbial cells. By using the acoustic sensor based on slot-mode a criterion of
E. coli
sensitivity to ampicillin was established. The advantages of this method are the ability to carry out the analysis directly in the liquid, the short analysis time (within 10–15 min), and the possibility to reusable sensor.
Integration of magnetism into semiconductor electronics would facilitate an all-in-one-chip computer. Ferromagnet/bulk semiconductor hybrids have been, so far, mainly considered as key devices to ...read out the ferromagnetism by means of spin injection. Here we demonstrate that a Mn-based ferromagnetic layer acts as an orientation-dependent separator for carrier spins confined in a semiconductor quantum well that is set apart from the ferromagnet by a barrier only a few nanometers thick. By this spin-separation effect, a non-equilibrium electron-spin polarization is accumulated in the quantum well due to spin-dependent electron transfer to the ferromagnet. The significant advance of this hybrid design is that the excellent optical properties of the quantum well are maintained. This opens up the possibility of optical readout of the ferromagnet's magnetization and control of the non-equilibrium spin polarization in non-magnetic quantum wells.
Assuming an existence of the anomalous triple electro-weak bosons interaction being defined by coupling constant λ we calculate its contribution to interactions of the Higgs with pairs of heavy ...particles. Bearing in mind experimental restrictions −0.011<λ<0.011 we present results for possible effects in processes pp→W+W−H,pp→W+ZH,pp→W−ZH,pp→t¯tH, pp→b¯bH. Effects could be significant with negative sign of λ in associated heavy quarks t,b pairs production with the Higgs. In calculations we rely on results of the non-perturbative approach to a spontaneous generation of effective interactions, which defines the form-factor of the three-boson anomalous interaction.
High-frequency fractionated electrograms recorded during atrial fibrillation (AF) in the posterior left atrium (PLA) and elsewhere are being used as target sites for catheter ablation. We tested the ...hypothesis that highly periodic electric waves emerging from AF sources at or near the PLA give rise to the most fractionated activity in adjacent locations.
Sustained AF was induced in 8 isolated sheep hearts (0.5 micromol/L acetylcholine). Endocardial videoimaging (DI-4-ANEPPS) and electric mapping of the PLA enabled spatial characterization of dominant frequencies (DFs) and a regularity index (ratio of DF to total power). Regularity index showed that fractionation was lowest within the area with the maximal DF (DFmax domain; 0.19+/-0.02) and highest within a band of &3 mm (0.16+/-0.02; P=0.047) at boundaries with lower-frequency domains. The numbers of spatiotemporal periodic episodes (25.9+/-2.3) and rotors per experiment (1.9+/-0.7) were also highest within the DFmax domain. Most commonly, breakthrough waves at the PLA traveled toward the rest of the atria (76.8+/-8.1% outward versus 23.2+/-8.1% inward; P<0.01). In both experiments and simulations with an atrial ionic model, fractionation at DFmax boundaries was associated with increased beat-to-beat variability of conduction velocity and directionality with wavebreak formation.
During stable AF, the PLA harbors regular, fast, and highly organized activity; the outer limit of the DFmax domain is the area where the most propagation pattern variability and fractionated activity occur. These new concepts introduce a new perspective in the clinical use of high-frequency fractionated electrograms to localize sources of AF precisely at the PLA and elsewhere.
Nitrogen-doped CVD diamond treated with electron irradiation and subsequent annealing at temperatures from 860 to 1900 °C was studied using fluorescence imaging, optical absorption and ...photoluminescence. It was found that nitrogen impurity produces many optical centers active throughout the infrared and visible spectral ranges. The most prominent of them active in IR spectral range are the centers related to nitrogen–hydrogen complexes. They produce absorption lines at 2827, 2874, 2906, 2949, 2990, 3031, 3107, 3123 and 3310 cm−1. Two characteristic absorptions at wavenumbers 1293 cm−1 and 1341 cm−1 were tentatively ascribed to a modified form of nitrogen A-aggregates. In the visible and near IR spectral ranges, characteristic nitrogen-related centers have zero-phonon lines (ZPLs) at 457, 462, 489, 498, 722.5, 852.5, 865.5, 868.5, 908, 921.5 and 924.5 nm. Some of them, e.g. 457, 462 and 498 nm centers, are unique of CVD diamond. It has been confirmed that the brightest pink color of electron-irradiated nitrogen-doped CVD diamond is produced by annealing at temperatures about 1000 °C. Annealing at temperatures over 1600 °C destroys the irradiation-induced pink color. It was found that the center 489 nm is a major absorption feature in the visible spectral range of electron-irradiated, nitrogen-doped CVD diamond. Green color of electron-irradiated, nitrogen-doped CVD diamond is caused by combined absorption of GR1 center and 489 nm center. It has been confirmed that NV defects produced in CVD diamond during growth are very temperature stable. They survive heating at temperatures at least 2000 °C. In contrast, NV defects produced by irradiation may anneal out at temperatures as low as 1600 °C. This much lower thermal stability of the radiation-induced NV defects is the result of their interaction with other radiation defects produced in their vicinity. A conclusion has been made that in nitrogen-doped CVD diamonds nitrogen atoms may form clusters. These clusters are probably the origin of the broad band luminescence at wavelengths 360, 390, 535 and 720 nm and a strong broadening of ZPLs of many optical centers.
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•In CVD diamond, a modified nitrogen A-aggregates produce two characteristic absorptions at 1293 and 1341 cm-1.•Nitrogen clusters may attribute multiple luminescence bands from UV to near IR spectral region, including very broad ZPLs.•Distinct peaks at 2827, 2874, 2906, 2949 and 2990 cm-1 in IR spectra can be related to nitrogen-hydrogen centers.•The ZPLs at 457, 462, 489, 498, 722.5, 852.5, 865.5, 868.5, 908, 921.5 and 924.5 nm are caused by nitrogen-related centers.•Annealing of NV defects at < 22000 ºC is the result of interaction with other radiation defects located in their vicinity.
Brain-derived neurotrophic factor (BDNF) modulates hippocampal plasticity and hippocampal-dependent memory in cell models and in animals. We examined the effects of a valine (val) to methionine (met) ...substitution in the 5′ pro-region of the human BDNF protein. In human subjects, the met allele was associated with poorer episodic memory, abnormal hippocampal activation assayed with fMRI, and lower hippocampal n-acetyl aspartate (NAA), assayed with MRI spectroscopy. Neurons transfected with met-BDNF-GFP showed lower depolarization-induced secretion, while constitutive secretion was unchanged. Furthermore, met-BDNF-GFP failed to localize to secretory granules or synapses. These results demonstrate a role for BDNF and its val/met polymorphism in human memory and hippocampal function and suggest val/met exerts these effects by impacting intracellular trafficking and activity-dependent secretion of BDNF.
The interactions between inhibitory fast‐spiking (FS) interneurons and excitatory pyramidal neurons contribute to the fundamental properties of cortical networks. An important role for FS ...interneurons in mediating rapid inhibition in local sensory and motor cortex microcircuits and processing thalamic inputs to the cortex has been shown in multiple reports; however, studies in the prefrontal cortex, a key neocortical region supporting working memory, are less numerous. In the present work, connections between layer 2/3 pyramidal cells and FS interneurons were studied with paired whole‐cell recordings in acute neocortical slices of the medial prefrontal cortex from juvenile rats. The connection rate between FS interneurons and pyramidal neurons was about 40% in each direction with 16% of pairs connected reciprocally. Excitatory and inhibitory connections had a high efficacy and a low neurotransmission failure rate. Sustained presynaptic activity decreased the amplitude of responses and increased the failure rate more in excitatory connections than in inhibitory connections. In the reciprocal connections between the FS and pyramidal neurons, inhibitory and excitatory neurotransmission was more efficient and had a lower failure rate than in the unidirectional connections; the differences increased during the train stimulation. These results suggest the presence of distinct preferential subnetworks between FS interneurons and pyramidal cells in the rat prefrontal cortex that might be specific for this cortical area.
Synaptic connections between layer 2/3 pyramidal cells and FS interneurons were studied with paired whole‐cell recordings in acute neocortical slices of the medial prefrontal cortex from juvenile rats. In the reciprocal connections the amplitude of postsynaptic responses was larger and neurotransmission had a lower failure rate than in the unidirectional connections. The differences between these types of connections persisted during the short‐train stimulation.
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•The main features of light induced gasification of waste were observed.•The gasification energy was estimated for two types of fuels (<6 MJ/kg).•The syngas contains the methane or ...hydrogen depending of external conditions.•The fuel temperature does not exceed the 370 K at the gasification.•The wettability of the coal defines the efficiency of the laser pyrolysis.
The laser processing becomes more and more popular for different objects and purposes including different fuels and combustibles. We have investigated experimentally some details of the light-induced conversion of the waste-derived coal-water slurry into the syngas. The process was “cold” enough (the temperature of the fuel was less than 350 K). The specific gasification energy strongly depends on the chosen content of the raw fuel and does not exceed the 6 MJ/kg. It was shown that there are two possible alternative processes with dominant production of the hydrogen or methane. The production of the combustible gases is accompanied with generation of certain amounts of SO2 and much less amount of CO.
This article describes calculations of the yield ratio of anti-particles to the yield of particles (
/
p
,
/
d
,
/
3
He) in proton–proton and nuclear–nuclear interactions using the self-similarity ...parameter in the central rapidity region. The used approach is based on the study of relativistic nuclear interactions in the four-velocity space. The results of the calculations are compared with the existing experimental data in a wide center-of-mass energy range (
SPS
,
RHIC
,
LHC
). Within this approach the inclusive spectra of pions and kaons and ratios of their yields in pp collisions have been successfully described earlier.
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