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After nearly 50 years of searching, the vacuum ultraviolet 229 Th nuclear isomeric transition has recently been directly laser excited 1 , 2 and measured with high spectroscopic precision 3 . Nuclear clocks based on this transition are expected to be more robust 4 , 5 than and may outperform 6 , 7 current optical atomic clocks. These clocks also promise sensitive tests for new physics beyond the standard model 5 , 8 , 9 , 10 , 11 – 12 . In light of these important advances and applications, a substantial increase in the need for 229 Th spectroscopy targets in several platforms is anticipated. However, the growth and handling of high-concentration 229 Th-doped crystals 5 used in previous measurements 1 , 2 – 3 , 13 , 14 are challenging because of the scarcity and radioactivity of the 229 Th material. Here we demonstrate a potentially scalable solution to these problems by performing laser excitation of the nuclear transition in 229 ThF 4 thin films grown using a physical vapour deposition process, consuming only micrograms of 229 Th material. The 229 ThF 4 thin films are intrinsically compatible with photonics platforms and nanofabrication tools for integration with laser sources and detectors, paving the way for an integrated and field-deployable solid-state nuclear clock with radioactivity up to three orders of magnitude smaller than typical 229 Th-doped crystals 1 , 2 – 3 , 13 . The high nuclear emitter density in 229 ThF 4 also potentially enables quantum optics studies in a new regime. Finally, we present the estimation of the performance of a nuclear clock based on a defect-free ThF 4 crystal. Laser excitation of the  229 Th isomer, potentially relevant for nuclear clocks, is reported in thorium fluoride thin films, which are less radioactive and amenable to integration compared with existing thorium-doped crystals.

An original multifractal algorithm is proposed for calculating the fractal characteristics of the cluster texture of biopolymer-inorganic (BIN) composites from microphotographic images (MPIs) of their texture, which allows one to determine the quantitative dependence of the mechanical properties of biopolymer–inorganic composites on the characteristics of their cluster texture. As a result of the studies conducted on the MPI texture of the “chitosan-silicon dioxide” BIN composites using a multifractal algorithm, it was found that such important indicators as strength and plasticity can be quantitatively described using generalized fractal pixel dimensions of MPI samples of the BIN composite. It was established that when the amount of silicon dioxide in the samples of the BIN composite changes, the mechanical characteristics of the BIN composites, such as strength and plasticity, can be quantitatively described using generalized fractal pixel dimensions of the MPIs of the BIN composite samples.

During tumor development cancer cells pass through several stages when cell morphology and migration abilities change remarkably. These stages are named epithelial-mesenchymal and mesenchymal-amoeboid transitions. The molecular mechanisms underlying cell motility are changing during these transitions. As result of transitions the cells acquire new characteristics and modes of motility. Cell migration becomes more independent from the environmental conditions, and thus cell dissemination becomes more aggressive, which leads to formation of distant metastases. In this review we discuss the characteristics of each of the transitions, cell morphology, and the specificity of cellular structures responsible for different modes of cell motility as well as molecular mechanisms regulating each transition.

The mechanisms of action of pyrimidine nucleoside derivatives on model lipid membranes of various compositions were studied. A systematic analysis of the tested agents’ effects on the membrane physicochemical properties was performed. Differential scanning microcalorimetry data indicated that the ability of nucleoside derivatives to disorder membrane lipids depended on the types of nucleoside bases and membrane-forming lipids. The 5′-norcarbocyclic uracil derivatives were found to be ineffective, while N4-alkylcytidines demonstrated the most pronounced effects, significantly decreasing the dipalmitoylphosphocholine melting temperature and cooperativity of phase transition. The elongation of hydrophobic acyl radicals potentiated the disordering action of N4-alkylcytidines, while an increase in hydrophilicity due to replacing deoxyribose with ribose inhibited this effect. The ability of compounds to form transmembrane pores was also tested. It was found that 5-alkyluridines produced single, ion-permeable pores in phosphatidylglycerol membranes, and that methoxy-mycolic acid and trehalose monooleate potentiated the pore-forming activity of alkyloxymethyldeoxyuridines. The results obtained open up perspectives for the development of innovative highly selective anti-tuberculosis agents, which may be characterized by a low risk of developing drug resistance due to the direct action on the membranes of the pathogen.

Background: Microsporum canis (Bodin, 1902) is a dermatophyte, which is widely represented in the developing and the developed world alike. Commonly transmitted from domestic animals it is particularly dangerous for immunosuppressed patients due to AIDS, cancer or transplant surgery. Search for new perspective antimycotic derivatives becomes an urgent task in the disease containment. Previously, several quinolinium analogs were screened for their antibacterial activity (E. coli, St. aurous) by our research team. Furthermore, some N-phenylbenzoquinaldinium derivatives have shown antifungal activity against Candida albicans and Candida krusei. Aims: In this study, we sought to investigate fungicidal properties of N-arylbenzoquinaldinium derivatives against a clinical strain of Microsporum canis for future medicinal applications. Materials and Methods: N-phenyl-[f]-benzoquinaldinium salts were prepared by a variation of the previously described technique and tested against a clinical strain of the fungus of Microsporum canis 114 harvested from pathogenic material of a patient (Perm, Russia, 2014). Results: N-phenyl-[f]-benzoquinaldinium tetrafluoroborate has shown antifungal activity par to (or exceeding) that of commercially available medication. Moreover, this benzoquinaldinium analog can be potentially labelled with tritium by our nuclear-chemical method, making it amenable for the sensitive pharmacokinetic studies. Conclusions: N-phenyl-[f]-benzoquinaldinium tetrafluoroborate has been shown as a promising compound for the further development of potent antifungal agents as well as radiotracers for further elucidation of biological pathways of antifungal activity.

Tuberculosis (TB) is the oldest human infection disease. Mortality from TB significantly decreased in the 20th century, because of vaccination and the widespread use of antibiotics. However, about a third of the world’s population is currently infected with Mycobacterium tuberculosis (Mtb) and the death rate from TB is about 1.4–2 million people per year. In the second half of the 20th century, new extensively multidrug-resistant strains of Mtb were identified, which are steadily increasing among TB patients. Therefore, there is an urgent need to develop new anti-TB drugs, which remains one of the priorities of pharmacology and medicinal chemistry. The antimycobacterial activity of nucleoside derivatives and analogues was revealed not so long ago, and a lot of studies on their antibacterial properties have been published. Despite the fact that there are no clinically used drugs based on nucleoside analogues, some progress has been made in this area. This review summarizes current research in the field of the design and study of inhibitors of mycobacteria, primarily Mtb.

— The data on the distribution of secular resonances in the areas of action of tesseral (orbital) resonances 1 : 5, 1 : 7, 1 : 9, 1 : 10 and 1 : 11 with the speed of rotation of the Earth, as well as an analysis of the dynamics of objects moving in the studied areas are presented. It is shown that secular resonances cover the areas under consideration very densely, which, together with orbital resonances, can lead to chaotization of the motion of objects. Using the example of the orbital evolution of NORAD catalog objects moving in the study area, the issue of the possibility of placing new satellite systems and recycling spent objects in this area is considered.

A series of novel 5′-norcarbocyclic derivatives of 5-alkoxymethyl or 5-alkyltriazolyl-methyl uracil were synthesized and the activity of the compounds evaluated against both Gram-positive and Gram-negative bacteria. The growth of Mycobacterium smegmatis was completely inhibited by the most active compounds at a MIC99 of 67 μg/mL (mc2155) and a MIC99 of 6.7–67 μg/mL (VKPM Ac 1339). Several compounds also showed the ability to inhibit the growth of attenuated strains of Mycobacterium tuberculosis ATCC 25177 (MIC99 28–61 μg/mL) and Mycobacterium bovis ATCC 35737 (MIC99 50–60 μg/mL), as well as two virulent strains of M. tuberculosis; a laboratory strain H37Rv (MIC99 20–50 μg/mL) and a clinical strain with multiple drug resistance MS-115 (MIC99 20–50 μg/mL). Transmission electron microscopy (TEM) evaluation of M. tuberculosis H37Rv bacterial cells treated with one of the compounds demonstrated destruction of the bacterial cell wall, suggesting that the mechanism of action for these compounds may be related to their interactions with bacteria cell walls.

The paper describes the improvements made by the authors to the previously published Numerical Model of the Motion of Artificial Lunar Satellites (ALS). The results of a study of the dynamics of cislunar objects obtained by numerical modeling are presented. It is shown that the short lifespan of low-flying objects in orbits, revealed by a number of authors, is explained solely by the influence of the complex gravitational field of the Moon, primarily the radial component of the force acting on the satellites. The features of the influence of light pressure (LP) on cislunar objects are considered. It is shown that LP expands the range of action of apsidal-nodal resonances that arise in the movement of cislunar objects.

Recently we have synthesized a set of pyrimidine nucleoside derivatives bearing extended alkyltriazolylmethyl substituents at position 5 of the nucleic base, and showed their significant activity against Mycobacterium tuberculosis virulent laboratory strain H37Rv as well as drug-resistant MS-115 strain. The presence of a lengthy hydrophobic substituent leads to the reduction of nucleoside water solubility making their antibacterial activity troublesome to study. A series of water-soluble forms of 5-modified 2ʹ-deoxyuridines 4a–c and 8a–c were synthesized. They appeared at least two orders more soluble compared with the parent compounds 1a and 1b. Their half-hydrolysis time was 5–12 h, which can be considered optimal for prodrugs used in clinics. Obtained compounds showed moderate activity (MIC 48–95 µg·ml−1) against some Gram-positive bacteria including resistant strains of Staphylococcus aureus and Mycobacterium smegmatis and were low cytotoxic for human cell lines (CD50 >> 100 µg·ml−1).