Terapascal static pressure generation with ultrahigh yield strength nanodiamond

Studies of materials’ properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications

Stress plays provoking role in hypertension-related stroke: Injuries of blood-brain barrier function

Chronic hypertension itself does not cause stroke but significantly decreases the resistant to stroke induced by stress due to exhausting of adaptive capacity of cerebral endothelium and decrease resistance of blood-brain barrier to stress

Terapascal static pressure generation with ultrahigh yield strength nanodiamond

Studies of materials’ properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications

A revision of the Palaearctic Pimeliini (Coleoptera: Tenebrionidae): a comparative analysis and systematic position of Eastern European and Asian taxa with dorso-lateral eyes

A taxonomic review of tenebrionid platyopoid genera of the subfamily Pimeliinae from Eastern Europe, Central Asia, Afghanistan, Iran and Pakistan is given. This group of taxa was known before 1994 as the tribe Platyopini Motschulsky, 1849, which is now interpreted as a junior synonym of Pimeliini Latreille, 1802. The group is different from other Pimeliini in having dorso-lateral eyes, located above the level of the genae, and it includes the following ultrapsammophilic genera at least from Central and Southern Asia: Apatopsis Semenov, 1891, Habrochiton Semenov-Tjan-Shansky, 1907, Habrobates Semenov, 1903 [= Kawiria Schuster, 1935 syn. nov.], Dietomorpha Reymond, 1938, Przewalskia Semenov, 1893, Mantichorula Reitter, 1889, Platyope Fischer von Waldheim, 1820 [= Homopsis Semenov, 1893 syn. nov.], Earophanta Semenov, 1903. These genera are distributed in almost all large deserts of Palaearctic Asia: Karakum, Kyzylkum, Muyunkum, Taklamakan, Gobi, Registan, Dasht-e-Kawir, Dasht-e-Lut, as well as in other arid and semi-arid sandy landscapes from European Russia to the south of Eastern Siberia. The group of platyopoid genera is polyphyletic. We propose at least two monophyletic branches: the Habrobates genus group (the first four genera mentioned above), which represents the subtribe Habrobatina Nabozhenko & S. Chigray subtrib. nov. and the Platyope genus group (latter four genera) within the nominotypical subtribe. A new species is described from Pakistan (Balochistan): Dietomorpha gonzalesi S. Chigray & Nabozhenko sp. nov. Platyope granulata Fischer von Waldheim, 1820 is recorded for Kazakhstan for the first time. The following synonymy is resurrected: Apatopsis grombczewskii Semenov, 1890 = Apatopsis conradti Semenov, 1890, syn. resurr. Two new combinations resulting from the synonymy of genera are given: Habrobates gabrieli Schuster, 1935 comb. nov. (from Kawiria), Platyope grumi Semenov, 1893 comb. nov. (from Homopsis). Lectotypes are designated for the following taxa: Apatopsis grombczewskii (Semenov, 1891), Apatopsis conradti Semenov, 1891, Habrochiton vernus Semenov-Tjan-Shansky, 1907, Habrobates vernalis Semenov, 1903, Kawiria gabrieli Schuster, 1935, Platyope dilatata Reitter, 1887; Mantichorula semenowi Reitter, 1889, Mantichorula grandis Semenov, 1893, Homopsis grumi Semenov, 1893, Platyope serrata Semenov, 1893, Platyope planidorsis Reitter, 1889, Platyope tomentosa Semenov, 1893. Additional information for type specimens studied by the authors is given for Habrochiton primaeveris Semenov-Tjan-Shansky, 1907 (holotype), Habrobates vejisovi Kelejnikova, 1977, Platyope ordossica Semenov-Tjan-Shansky, 1907 (holotype), Earophanta autumnalis Semenov, 1903 (holotype, junior synonym of E. planidorsis Reitter, 1889), Earophanta loudoni Semenov, 1903 (holotype, junior synonym of Earophanta pilosissima Reitter, 1895), Earophanta pubescens Skopin, 1960 (holotype, paratypes), Earophanta beludzhistana Bogatchev, 1957 (holotype)

Encapsulins—Bacterial Protein Nanocompartments: Structure, Properties, and Application

Recently, a new class of prokaryotic compartments, collectively called encapsulins or protein nanocompartments, has been discovered. The shell proteins of these structures self-organize to form icosahedral compartments with a diameter of 25–42 nm, while one or more cargo proteins with various functions can be encapsulated in the nanocompartment. Non-native cargo proteins can be loaded into nanocompartments and the surface of the shells can be further functionalized, which allows for developing targeted drug delivery systems or using encapsulins as contrast agents for magnetic resonance imaging. Since the genes encoding encapsulins can be integrated into the cell genome, encapsulins are attractive for investigation in various scientific fields, including biomedicine and nanotechnology

Low-Frequency Dynamic Magnetic Fields Decrease Cellular Uptake of Magnetic Nanoparticles

Magnetic nanoparticles have gained attention as a potential structure for therapy and diagnosing oncological diseases. The key property of the magnetic nanoparticles is the ability to respond to an external magnetic field. It is known that magnetofection causes an increase in the cellular uptake of RNA and DNA in complexes with magnetic nanoparticles in the presence of a permanent magnetic field. However, the influence of a dynamic magnetic field on the internalization of MNPs is not clear. In this work, we propose the idea that applying external low-frequency dynamic magnetic fields may decrease the cellular uptake, such as macrophages and malignant neuroblastoma. Using fluorescence microscopy and atomic emission spectroscopy, we found that oscillating magnetic fields decreased the cellular uptake of magnetic nanoparticles compared to untreated cells by up to 46%. In SH-SY5Y tumor cells and macrophage RAW264.7 cells, the absolute values of Fe per cell differed by 0.10 pg/cell and 0.33 pg/cell between treated and untreated cells, respectively. These results can be applied in the control of the cellular uptake in different areas of biomedicine

Myxococcus xanthus Encapsulin as a Promising Platform for Intracellular Protein Delivery

Introducing a new genetically encoded material containing a photoactivatable label as a model cargo protein, based on Myxococcus xanthus (Mx) encapsulin system stably expressed in human 293T cells. Encapsulin from Mx is known to be a protein-based container for a ferritin-like cargo in its shell which could be replaced with an exogenous cargo protein, resulting in a modified encapsulin system. We replaced Mx natural cargo with a foreign photoactivatable mCherry (PAmCherry) fluorescent protein and isolated encapsulins, containing PAmCherry, from 293T cells. Isolated Mx encapsulin shells containing photoactivatable label can be internalized by macrophages, wherein the PAmCherry fluorescent signal remains clearly visible. We believe that a genetically encoded nanocarrier system obtained in this study, can be used as a platform for controllable delivery of protein/peptide therapeutics in vitro

Encapsulin Based Self-Assembling Iron-Containing Protein Nanoparticles for Stem Cells MRI Visualization

Over the past decade, cell therapy has found many applications in the treatment of different diseases. Some of the cells already used in clinical practice include stem cells and CAR-T cells. Compared with traditional drugs, living cells are much more complicated systems that must be strictly controlled to avoid undesirable migration, differentiation, or proliferation. One of the approaches used to prevent such side effects involves monitoring cell distribution in the human body by any noninvasive technique, such as magnetic resonance imaging (MRI). Long-term tracking of stem cells with artificial magnetic labels, such as magnetic nanoparticles, is quite problematic because such labels can affect the metabolic process and cell viability. Additionally, the concentration of exogenous labels will decrease during cell division, leading to a corresponding decrease in signal intensity. In the current work, we present a new type of genetically encoded label based on encapsulin from Myxococcus xanthus bacteria, stably expressed in human mesenchymal stem cells (MSCs) and coexpressed with ferroxidase as a cargo protein for nanoparticles’ synthesis inside encapsulin shells. mZip14 protein was expressed for the enhancement of iron transport into the cell. Together, these three proteins led to the synthesis of iron-containing nanoparticles in mesenchymal stem cells—without affecting cell viability—and increased contrast properties of MSCs in MRI

New Experimental Model of Brain Tumors in Brains of Adult Immunocompetent Rats

Aims: Xenograft models, namely heterotransplantation of human cancer cells or tumor biopsies into immunodeficient rodents are the major preclinical approach for the development of novel cancer therapeutics. However, in these models the animals must be used only after the severe systemic immune suppression in order to ensure graft survival. Thus, additional new human brain tumor models without immune suppression of the recipient rodent may be required. Place and Duration of Study: Laboratory of Immunochemistry, V.P. Serbsky National Research Centre for Social and Forensic Psychiatry and Department of Nanobiotechnology, N.I. Pirogov Russian State Medical University and Department of Biosynthesis of Nucleic Acids, Institute of Molecular Biology and Genetics between June 2009 and July 2010. Methodology: Brain tumor modeling was performed by intracerebral stereotactic implantation of cells to the healthy adult rats without any artificial immunodepression. Cells were implanted to the striatum region of ketamine-anesthetized rats at specific coordinates according to Swanson's rat brain atlas. Tumor growth was monitored weekly via registration of neurological signs and in vivo Bruker MRI system. Results: On the 21st day after implantation of C6 glioma, U251 or 293_CHI3L1 cells severe neurological deficit appeared in rats. Huge intracerebral tumors were found in each animal under investigation while no tumor growth was observed for at least 8 weeks in rats injected with empty vector-transfected 293 cells. Tumors contained the dense superficial cell layer and prominent lobules with central newly ingrowing blood vessels. Histological assay revealed displacement of median cerebral structures and hydrocephalus in contralateral hemisphere. All tumors were surrounded by numerous GFAP-positive reactive astrocytes. Conclusion: Positive results with transplantation of 293_CHI3L1 cells into adult rat brains without any immunosupression show the validity of this animal model. In all experiments such implantations provoked malignant tumor formation while there were no visible tumors in control rats. We believe this to be the first animal model of human brain tumor that displays the possibility to study various biologic features of and host therapeutic response to brain tumor in an immunocompetent host

Structure and Magnetic Properties of SrFe12−xInxO19 Compounds for Magnetic Hyperthermia Applications

In this work, complex studies of the structure and magnetic properties of SrFe12−xInxO19 powders obtained by the mechanochemical and citrate methods were carried out. The solubility of In in strontium hexaferrite SrFe₁₂O₁₉ at 1200 °C was determined. The structure and properties of the powders were studied using X-ray diffraction analysis, Mössbauer spectroscopy and scanning electron microscopy. Measurements of magnetic properties in magnetic fields up to 1600 kA/m were also performed. Additionally, the hyperthermia effect was investigated. The possibility of controlling the coercivity of the samples in the range from 188.9 kA/m to 22.3 kA/m and saturation magnetization from 63.5 A·m2/kg to 44.2 A·m2/kg with an increase in the degree of In doping was also demonstrated. Investigation of the magnetic hyperthermia of the samples was carried out by temperature measurement with an IR camera when they were introduced into alternating magnetic fields of various frequencies (144, 261 and 508 kHz) and amplitudes (between 11.96 and 19.94 kA/m). According to the study result, there was detected the heating of the SrFe12−xInxO19 sample (x = 1.7). The highest values of magnetic hyperthermia of the sample were observed in a 19.94 kA/m magnetic field and a frequency of 261 kHz. At a concentration of 56.67 g/L, the sample was heated from 23 to 41 °C within 2 min. The parameters SLP (specific loss power) and ILP (intrinsic loss power) were calculated