The Error Probability of the Miller–Rabin Primality Test

© 2018, Pleiades Publishing, Ltd. In our paper we give theoretical and practical estimations of the error probability in the well-known Miller–Rabin probabilistic primality test. We show that a theoretical probability of error 0.25 for a single round of the test is very overestimated and, in fact, error is diminishing with the growth of length of numbers involved by a rate limited with ln n/n

Uptake of halloysite clay nanotubes by human cells: Colourimetric viability tests and microscopy study

© 2018 This study is a systemic investigation of the uptake and toxicity of halloysite nanotubes using human adenocarcinoma epithelial cells (A549). A549 cells were chosen as a popular model of cancer cells extensively studied in nanotoxicity and drug delivery research. The adverse effects of a range of halloysite concentrations were evaluated. The viability of A549 cells was determined using several colourimetric assays. Dark-field microscopy was used to visualize the uptake and distribution of halloysite nanotubes in cells. The morphology of the cells was evaluated using dark-field, transmission electron and atomic force microscopies. The results showed that halloysite had a dose-dependent effect on human cells at concentrations of 5–900 μg per 105 cells in the MTT assay. The reduced toxicity of halloysite nanotubes at lower concentrations (5–75 μg per 105 cells) was additionally supported by the results of other colorimetric assays. Microscopy assays have demonstrated that the nanotubes, though affecting the biochemical processes, do not alter the morphology of the cells and do not penetrate into the nuclei

Development of Biocompatible Glass Substrate With Surface Nanotopography

The work was performed according to the Russian Government Program of Competitive Growth of Kazan Federal University and funded by the Russian Presidential grant MК-4498.2018.

Towards effective COVID\u201119 vaccines: Updates, perspectives and challenges (Review)

In the current context of the pandemic triggered by SARS-COV-2, the immunization of the population through vaccination is recognized as a public health priority. In the case of SARS\u2011COV\u20112, the genetic sequencing was done quickly, in one month. Since then, worldwide research has focused on obtaining a vaccine. This has a major economic impact because new technological platforms and advanced genetic engineering procedures are required to obtain a COVID\u201119 vaccine. The most difficult scientific challenge for this future vaccine obtained in the laboratory is the proof of clinical safety and efficacy. The biggest challenge of manufacturing is the construction and validation of production platforms capable of making the vaccine on a large scale

Abstract OR-8: Cryo-EM Structure of Mature Yellow Fever Virus

Background: Yellow fever virus (YFV) is the prototype virus of the genus Flavivirus. It is endemic to sub-Saharan Africa and tropical South America. YF disease ranges from asymptomatic to severe jaundice and hemorrhagic fever. The flavivirus virion core is enveloped by a lipid membrane with integrated membrane (M) proteins and envelope (E) proteins that form the outer surface of the virion. The Е protein provides stability to the viral particle and is responsible for early infection stages. Flaviviruses are heterogeneous in nature, which is related to their maturation process. Samples always contain mature, immature, half-mature, and damaged particles. Thus, cryo-EM is a method of choice for their structure determination. During the early stages of cryo-EM development, structures of flaviviruses were studied at 10–20 Å resolution. However, due to the progress of recent years, it became possible to determine flavivirus structures at a resolution of 5.6-2.6 Å. The cryo-EM method was used to obtain structural data of virions of dengue fever virus, Zika virus, TBE virus, etc. For YFV, only the cryo-EM structure of the immature virions at a low resolution of 25 Å was determined (Y. Zhang et al. 2003 doi:10.1093/emboj/cdg270). However, the structure of mature (most infectious) YFV particles is still unknown. Methods: Virus sample was produced in Vero cell culture. YFV-17D was inactivated and purified using ultracentrifugation. The concentration of viral particles in the target inactivated YFV-17D (iYFV-17D) was evaluated by spectrophotometry and by estimating the concentration of E protein determined by PAGE electrophoresis. Preliminary quality control of iYFV-17D sample was performed using negative staining TEM. Cryo-EM data were collected using cryo-TEM Krios (Thermo-Fisher, USA) at 300kV using DED Falcon II. Dataset was preprocessed using Warp. Further processing was performed in Relion 3.1 and CisTEM. Model building was carried out using Isolde, Phenix and Coot software. Results: A protocol of production and purification of highly concentrated (~2x1012) monodisperse inactivated iYFV-17D sample was developed. Cryo-EM structure of mature iYFV was solved at 4.1 Å resolution. The structure of YFV is similar to other known flavivirus structures, with 180 copies of protein E arranged in a herringbone pattern that makes up the icosahedral shell. Conclusion: The high-resolution structure of mature iYFV-17D allowed to elucidate special features of this flavivirus and may be useful for vaccine improvement and drug development

Fluorescence and cytotoxicity of cadmium sulfide quantum dots stabilized on clay nanotubes

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Quantum dots (QD) are widely used for cellular labeling due to enhanced brightness, resistance to photobleaching, and multicolor light emissions. CdS and CdxZn1−xS nanoparticles with sizes of 6–8 nm were synthesized via a ligand assisted technique inside and outside of 50 nm diameter halloysite clay nanotubes (QD were immobilized on the tube’s surface). The halloysite– QD composites were tested by labeling human skin fibroblasts and prostate cancer cells. In human cell cultures, halloysite–QD systems were internalized by living cells, and demonstrated intense and stable fluorescence combined with pronounced nanotube light scattering. The best signal stability was observed for QD that were synthesized externally on the amino-grafted halloysite. The best cell viability was observed for CdxZn1−xS QD immobilized onto the azine-grafted halloysite. The possibility to use QD clay nanotube core-shell nanoarchitectures for the intracellular labeling was demonstrated. A pronounced scattering and fluorescence by halloysite–QD systems allows for their promising usage as markers for biomedical applications

Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN