Solid-state quantum emitters are in high demand for emerging technologies such as advanced sensing and quantum information processing. Generally, these emitters are not sufficiently bright for ...practical applications, and a promising solution consists in coupling them to plasmonic nanostructures. Plasmonic nanostructures support broadband modes, making it possible to speed up the fluorescence emission in room-temperature emitters by several orders of magnitude. However, one has not yet achieved such a fluorescence lifetime shortening without a substantial loss in emission efficiency, largely because of strong absorption in metals and emitter bleaching. Here, we demonstrate ultrabright single-photon emission from photostable nitrogen-vacancy (NV) centers in nanodiamonds coupled to plasmonic nanocavities made of low-loss single-crystalline silver. We observe a 70-fold difference between the average fluorescence lifetimes and a 90-fold increase in the average detected saturated intensity. The nanocavity-coupled NVs produce up to 35 million photon counts per second, several times more than the previously reported rates from room-temperature quantum emitters.
In 2016–2017, several subtypes of the highly pathogenic avian influenza (HPAI) virus were isolated on the territory of Russia. In the autumn of 2016, during the avian influenza virus surveillance in ...the territory of the Kamchatka region of Russia the HPAI A(H5N5) influenza virus was isolated. Then, during 2016–2017, multiple outbreaks among wild birds and poultry caused by HPAI A(H5N8) avian influenza virus were recorded in European part of Russia. At the end of 2017, an outbreak among poultry caused by HPAI A(H5N2) influenza virus was recorded in the European part of Russia. Phylogenetic analysis of HA of the A(H5N5), A(H5N8), A(H5N2) showed the strains belong to the clade 2.3.4.4 b. All isolated strains were antigenically closely related to candidate vaccine viruses of clade 2.3.4.4 and showed high virulence in mice. Genetic analysis revealed presence of genetic markers potentially related to high virulence in mice in all studied viruses.
Fused silica glass is a material of choice for micromechanical, microfluidic, and optical devices due to its chemical resistance, optical, electrical, and mechanical performance. Wet etching is the ...key method for fabricating of such microdevices. Protective mask integrity is a big challenge due extremely aggressive properties of etching solution. Here, we propose multilevel microstructures fabrication route based on fused silica deep etching through a stepped mask. First, we provide an analysis of a fused silica dissolution mechanism in buffered oxide etching (BOE) solution and calculate the main fluoride fractions like Formula: see text, Formula: see text, Formula: see text as a function of pH and NH
F:HF ratio. Then, we experimentally investigate the influence of BOE composition (1:1-14:1) on the mask resistance, etch rate and profile isotropy during deep etching through a metal/photoresist mask. Finally, we demonstrate a high-quality multilevel over-200 μm etching process with the rate up to 3 μm/min, which could be of a great interest for advanced microdevices with flexure suspensions, inertial masses, microchannels, and through-wafer holes.
The influenza epidemic in 2015-2016 in Russia is characterized by a sharp increase of influenza cases (beginning from the second week of 2016) with increased fatalities. Influenza was confirmed in 20 ...fatal cases registered among children (0-10 years), in 5 cases among pregnant women, and in 173 cases among elderly people (60 years and older). Two hundred and ninety nine people died from influenza were patients with some chronic problems. The overwhelming majority among the deceased (more than 98%) were not vaccinated against influenza. We isolated 109 influenza A(H1N1)pdm09 and one A(H3N2) virus strains from 501 autopsy material samples. The antigenic features of the strains were similar to the vaccine strains. A phylogenic analysis of hemagglutinin revealed that influenza A(H1N1)pdm09 virus strains belonged to 6B genetic group that had two main dominant subgroups during the 2015-2016 season. In Russia strains of the first group predominated. We registered an increased proportion of strains with D222G mutation in receptor-binding site. A herd immunity analysis carried out immediately prior to the epidemic showed that 34.4% blood sera samples collected in different regions of Russia were positive to A/California/07/09(H1N1)pdm09. We came to a conclusion that public awareness enhancement is necessary to reduce unreasonable refusals of vaccination.
The Indium Tin Oxide (ITO) platform is one of the promising solutions for state-of-the-art integrated optical modulators towards low-loss silicon photonics applications. One of the key challenges on ...this way is to optimize ITO-based thin films stacks for electro-optic modulators with both high extinction ratio and low insertion loss. In this paper we demonstrate the e-beam evaporation technology of 20 nm-thick ITO films with low extinction coefficient of 0.14 (N
= 3.7·10
cm
) at 1550 nm wavelength and wide range of carrier concentrations (from 1 to 10 × 10
cm
). We investigate ITO films with amorphous, heterogeneously crystalline, homogeneously crystalline with hidden coarse grains and pronounced coarsely crystalline structure to achieve the desired optical and electrical parameters. Here we report the mechanism of oxygen migration in ITO film crystallization based on observed morphological features under low-energy growth conditions. Finally, we experimentally compare the current-voltage and optical characteristics of three electro-optic active elements based on ITO film stacks and reach strong ITO dielectric permittivity variation induced by charge accumulation/depletion (Δn = 0.199, Δk = 0.240 at λ = 1550 nm under ± 16 V). Our simulations and experimental results demonstrate the unique potential to create integrated GHz-range electro-optical modulators with sub-dB losses.
It is quite common part of the data analysis in High Energy Physics to train a classifier for signal and background separation. In case the signal under investigation is a rare process, the signal ...sample is simulated and background sample is taken from the real data. Such setting create an unnecessary bias: the classifier might learn not the characteristic of the signal but the characteristic of the imperfect simulation. So the challenge is to train the classifier in such way that it picks up signal/background difference and doesnt overfit to the simulation-specific features. The suggested approach is based on cross-domain adaptation technique using neural networks with gradient reversal. The network architecture is a dense multi-branch structure. One branch is responsible for the signal/background discrimination, the second branch helps to avoid the overfitting on the Monte-Carlo training dataset. The tests showed that this architecture is a robust mechanism for choosing trade-offs between discrimination power and overfitting. So the resulting networks successfully distinguishes the signal from the background, but does not distinguish simulated events from the real ones. Moreover, such architecture could to be easily extended with more branches, and each one could be responsible for specific discrete and continuous domains. For example, the additional third network's branch could help to reduce the correlation between the classifier predictions and reconstructed mass of the decay, thereby making such approach highly viable for wide variety of physics searches. But such network's extensions weren't investigated during this work.
The energetic performances of different “Silicalite-1–LiCl aqueous solution” systems were evaluated under high pressure. Depending on the LiCl concentration in the aqueous medium (0 M, 5 M, 10 M, 20 ...M), an increase of the intrusion and extrusion pressures and therefore of the stored (∼10, ∼13, ∼19, ∼31 J/g) and restored (∼10, ∼13, ∼18, ∼27 J/g) energies are observed. Thus, compared to the “Silicalite-1–water” system, the stored energy is tripled in the case of “Silicalite-1–LiCl 20 M” system. Several characterizations (XRD, TG, NMR, N2 physisorption, ICP/OES, ...) have been realized before and after intrusion–extrusion experiments in order to reveal the presence or the lack of defects and the possible presence of lithium ions in the material after such experiments. At the short-range order, solid state NMR spectroscopy get evidence of the presence of Q2 and Q3 groups revealing the breaking of some siloxane bridges after the intrusion-extrusion steps and thus the creation of hydroxyl groups set in evidence by TG experiments. Only few traces of lithium (1 atom per unit cell) were found by ICP/OES analysis.
Vaccination of the population is one of the most effective countermeasures in responding to the pandemic caused by novel coronavirus infection. Therefore, scientists all over the world have been ...working to develop effective and safe vaccines. We have developed a synthetic peptide vaccine, EpiVacCorona, against novel SARS-CoV-2 coronavirus, which is a suspension for intramuscular administration containing a composition of chemically synthesized peptide immunogens of the S protein of SARS-CoV-2 coronavirus conjugated to a carrier protein and adsorbed on aluminum hydroxide. Phase I–II clinical trials of the vaccine have started that consist of two stages: Stage 1 is an open study of the safety, reactogenicity, and immunological activity of the vaccine with the involvement of 14 volunteers aged 18–30 years; Stage 2 is a single blind, comparative, randomized placebo-controlled study with the involvement of 86 volunteers. The study involved volunteers aged 18–60 years; the vaccine was injected intramuscularly twice, spaced 21 days apart between injections. All local reactions in response to vaccine administration were mild, such as a short-term pain at the injection site. There were no signs of development of local or systemic adverse reactions. The two-dose vaccination scheme induced the production of antibodies, specific to the antigens that make up the vaccine, in 100% of the volunteers. Seroconversion with a neutralizing antibody titer ≥ 1:20 was reported in 100% of the volunteers 21 days following the second immunization dose. No seroconversion was reported in the groups of volunteers vaccinated with a placebo. The peptide-based EpiVacCorona Vaccine has low reactogenicity and is a safe, immunogenic product. Clinical Trials Identifier: NCT04527575.
We demonstrate the optical medium for surface plasmon-polariton wave (SPP) propagation with ultra low losses corresponding to the theoretically limited values. The unique element of the optical ...medium is an atomically-flat single-crystalline silver thin film that provides extremely low losses. The SPP excited on the surface of such thin films (λ = 780 nm) is characterized by a SPP propagation length equal to 200 µm, which is twice longer than previously reported experimental results and corresponds to theoretically limited values for silver films.
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