The natural 5-azaindoles, marine sponge guitarrin C and D, were observed to exert inhibitory activity against a highly active alkaline phosphatase (ALP) CmAP of the PhoA family from the marine bacterium , with IC values of 8.5 and 110 µM, respectively. The superimposition of CmAP complexes with -nitrophenyl phosphate (NPP), a commonly used chromogenic aryl substrate for ALP, and the inhibitory guitarrins C, D, and the non-inhibitory guitarrins A, B, and E revealed that the presence of a carboxyl group at C6 together with a hydroxyl group at C8 is a prerequisite for the inhibitory effect of 5-azaindoles on ALP activity.
View Article and Find Full Text PDFStonikacidin A (), the first representative of a new class of 4-bromopyrrole alkaloids containing an aldonic acid core, was isolated from the marine sponge . The compound is named in honor of Prof. Valentin A.
View Article and Find Full Text PDFSufficiently fast continuous measurements of the position of an oscillator approach measurements projective on position eigenstates. We evidence the transition into the projective regime for a spin oscillator within an ensemble of 2 × 10 room-temperature atoms by observing correlations between the quadratures of the meter light field. These correlations squeeze the fluctuations of one light quadrature below the vacuum level.
View Article and Find Full Text PDFWe present a new, to the best of our knowledge, type of vector three-dimensional dissipative optical solitons with more extended degrees of freedom in a laser or laser medium with saturable absorption. These solitons are reconfigurable, include polarization singularities, and have various mutual orientations of nearly toroidal localization domains of polarization components. Numerical modeling confirms the stability of these solitons and breathers and reveals their symmetry and even "supersymmetry," as well as transformations when parameters leave the stability region.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2024
Bubbles are extensively explored as gas and energy carriers. However, despite notable progress, the bubble transport mechanisms are still poorly understood. At the present time there is not sufficient understanding of whether the body or surface forces play a major role in bubble transport in liquid interfacial systems.
View Article and Find Full Text PDFRegular measurements allow predicting the future and retrodicting the past of quantum systems. Time-nonlocal measurements can leave the future and the past uncertain, yet establish a relation between them. We show that continuous time-nonlocal measurements can be used to transfer a quantum state via teleportation or direct transmission.
View Article and Find Full Text PDFWe analyze the effect of frequency locking for polarization components of a semiconductor laser with fast gain, saturating absorption, and weak anisotropy. A mode of alternation of topological indices when leaving the locking area was found.
View Article and Find Full Text PDFNickel alloy high-speed processing technology using ball-end mills is characterized by high contact temperature and leads to accelerated tool wear. One of the effective ways to increase its reliability and service life is to modify the surface by applying functional antifriction layers in addition to wear-resistant coatings. Diamond-like carbon is often used as the latter.
View Article and Find Full Text PDFCreating systems for monitoring technology processes based on concentrated energy flows is an urgent and challenging task for automated production. Similar processes accompany such processing technologies: intensive thermal energy transfer to the substance, heating, development of the melting and evaporation or sublimation, ionization, and expansion of the released substance. It is accompanied by structural and phase rearrangements, local changes in volumes, chemical reactions that cause perturbations of the elastic medium, and the propagation of longitudinal and transverse waves in a wide frequency range.
View Article and Find Full Text PDFMed Gas Res
October 2022
Molecular hydrogen (H) has been considered a preventive and therapeutic medical gas in numerous diseases. The study aimed to investigate the potential role of molecular hydrogen as a component of anesthesia in surgical treatment with cardiopulmonary bypass (CPB) of acquired valve defects on the functional state of red blood cells (RBC) and functional indicators of cardiac activity. This clinical trial was conducted with 20 patients referring to the Specialized Cardiosurgical Clinical Hospital, Nizhny Novgorod, Russian Federation, who underwent elective surgery with CPB.
View Article and Find Full Text PDFThe cytotoxicity-bioassay-guided fractionation of the ethanol extract from the marine sponge , whose 1--alkyl--glycerol ethers (AGEs) have not been investigated so far, led to the isolation of a complex lipid fraction containing, along with previously known compounds, six new lipids of the AGE type. The composition of the AGE fraction as well as the structures of 6 new and 22 previously known compounds were established using H and C NMR, GC/MS, and chemical conversion methods. The new AGEs were identified as: 1--(Z-docos-15-enyl)--glycerol (), 1--(Z-docos-17-enyl)--glycerol (), 1--(Z-tricos-15-enyl)--glycerol (), 1--(Z-tricos-16-enyl)--glycerol (), 1--(Z-tricos-17-enyl)--glycerol (), and 1--(Z-tetracos-15-enyl)--glycerol ().
View Article and Find Full Text PDFToporosides A-D (-), new ω-glycosylated fatty acid amides, were isolated from the sponge . The structures of these compounds, including absolute configurations of stereogenic centers, were established using analysis of 1D and 2D NMR, ECD, and HR mass spectra as well as chemical transformations. Toporosides A () and B () are the first lipids containing a cyclopentenyl α,β-unsaturated carbonyl moiety in the polymethylene chain.
View Article and Find Full Text PDFOxygen-selective membranes are likely to play a leading part in the future separation processes relevant to energy engineering. A newly developed molten copper and vanadium oxide-based diffusion-bubbling membrane with core-shell structure and fast combined oxygen mass transfer is a promising candidate for efficient oxygen separation. In this work, the oxygen bubble nucleation and transport properties of the diffusion-bubbling membrane were experimentally and theoretically studied.
View Article and Find Full Text PDFWe analyze, to the best of our knowledge, a new type of topological optical solitons in lasers with fast saturable absorption, which is intermediate between 2D and 3D ones. Being generated by 2D laser solitons, such 3D dissipative solitons in a laser cavity of length have a number of vortex lines, which are straight for under-critical values and spiral for larger . For supercritical , a vortex with multiple topological charges >1 in generating 2D solitons transforms into separate vortex lines.
View Article and Find Full Text PDFOxygen is the second-largest-volume industrial gas that is mainly produced using cryogenic air separation. However, the state-of-the-art cryogenic technology thermodynamic efficiency has approached a theoretical limit as near as is practicable. Therefore, there is stimulus to develop an alternative technology for efficient oxygen separation from air.
View Article and Find Full Text PDFThe mechanism of the material destruction under discharge pulses and material removal mechanism based on the thermochemical nature of the electrical erosion during electrical discharge machining of conductive materials were researched. The experiments were conducted for two structural materials used in the aerospace industry, namely austenite anticorrosion X10CrNiTi18-10 (12kH18N10T) steel and 2024 (D16) duralumin, machined by a brass tool of 0.25 mm in diameter in a deionized water medium.
View Article and Find Full Text PDFExtant Canis lupus genetic diversity can be grouped into three phylogenetically distinct clades: Eurasian and American wolves and domestic dogs. Genetic studies have suggested these groups trace their origins to a wolf population that expanded during the last glacial maximum (LGM) and replaced local wolf populations. Moreover, ancient genomes from the Yana basin and the Taimyr peninsula provided evidence of at least one extinct wolf lineage that dwelled in Siberia during the Pleistocene.
View Article and Find Full Text PDFDogs were the first domestic animal, but little is known about their population history and to what extent it was linked to humans. We sequenced 27 ancient dog genomes and found that all dogs share a common ancestry distinct from present-day wolves, with limited gene flow from wolves since domestication but substantial dog-to-wolf gene flow. By 11,000 years ago, at least five major ancestry lineages had diversified, demonstrating a deep genetic history of dogs during the Paleolithic.
View Article and Find Full Text PDFAncient DNA has significantly improved our understanding of the evolution and population history of extinct megafauna. However, few studies have used complete ancient genomes to examine species responses to climate change prior to extinction. The woolly rhinoceros (Coelodonta antiquitatis) was a cold-adapted megaherbivore widely distributed across northern Eurasia during the Late Pleistocene and became extinct approximately 14 thousand years before present (ka BP).
View Article and Find Full Text PDFThe cave lion is an extinct felid that was widespread across the Holarctic throughout the Late Pleistocene. Its closest extant relative is the lion (Panthera leo), but the timing of the divergence between these two taxa, as well as their taxonomic ranking are contentious. In this study we analyse 31 mitochondrial genome sequences from cave lion individuals that, through a combination of C and genetic tip dating, are estimated to be from dates extending well into the mid-Pleistocene.
View Article and Find Full Text PDFNew bicyclic guanidine alkaloid, urupocidin C (Ur-C) along with the previously known urupocidin A (Ur-A) were isolated from the rare deep-sea marine sponge Monanchora pulchra, harvested in Northwestern Pacific waters. The unique structure of Ur-C was elucidated using 1D and 2D NMR spectroscopy as well as mass spectra. We discovered a promising selectivity of both alkaloids for human prostate cancer (PCa) cells, including highly drug-resistant lines, compared to non-malignant cells.
View Article and Find Full Text PDFPhilos Trans R Soc Lond B Biol Sci
December 2019
Ancient DNA provides a powerful means to investigate the timing, rate and extent of population declines caused by extrinsic factors, such as past climate change and human activities. One species probably affected by both these factors is the arctic fox, which had a large distribution during the last glaciation that subsequently contracted at the start of the Holocene. More recently, the arctic fox population in Scandinavia went through a demographic bottleneck owing to human persecution.
View Article and Find Full Text PDFWe analyze a cavity optomechanical setup, in which the position of an oscillator modulates the internal optical loss. We show that, in contrast to systems with a fixed internal loss, in such a setup, quantum-limited position measurements can be performed and formulate conditions under which it is possible. Additionally, under these conditions the setup exhibits a number of potential benefits for practical operation, including the complete absence of dynamical backaction and optomechanical instability, rejection of classical laser noise, and thermal fluctuations of cavity frequency from the measurement record.
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