180 results on '"Oleg A, Andreev"'
Search Results
2. Targeted intracellular delivery of dimeric STINGa by two pHLIP peptides for treatment of solid tumors
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Anna Moshnikova, Michael DuPont, Marissa Iraca, Craig Klumpp, Hannah Visca, Dana Allababidi, Phoebe Pelzer, Donald M. Engelman, Oleg A. Andreev, and Yana K. Reshetnyak
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tumor acidity ,cold tumors ,biophysics ,imaging ,immuno-suppressive tumors ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Introduction: We have developed a delivery approach that uses two pHLIP peptides that collaborate in the targeted intracellular delivery of a single payload, dimeric STINGa (dMSA).Methods: dMSA was conjugated with two pHLIP peptides via S-S cleavable self-immolating linkers to form 2pHLIP-dMSA.Results: Biophysical studies were carried out to confirm pH-triggered interactions of the 2pHLIP-dMSA with membrane lipid bilayers. The kinetics of linker self-immolation and dMSA release, the pharmacokinetics, the binding to plasma proteins, the stability of the agent in plasma, the targeting and resulting cytokine activation in tumors, and the biodistribution of the construct was investigated. This is the first study demonstrating that combining the energy of the membrane-associated folding of two pHLIPs can be utilized to enhance the targeted intracellular delivery of large therapeutic cargo payloads.Discussion: Linking two pHLIPs to the cargo extends blood half-life, and targeted delivery of dimeric STINGa induces tumor eradication and the development of robust anti-cancer immunity.
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- 2024
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3. Aiming the magic bullet: targeted delivery of imaging and therapeutic agents to solid tumors by pHLIP peptides
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Yana K. Reshetnyak, Oleg A. Andreev, and Donald M. Engelman
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pHLIP targeting of cell acidity ,cell acidity as a biomarker ,targeting diverse tumor cells ,immune therapy strategies ,targeted nanoparticle delivery ,tumor imaging and diagnosis ,Therapeutics. Pharmacology ,RM1-950 - Abstract
The family of pH (Low) Insertion Peptides (pHLIP) comprises a tumor-agnostic technology that uses the low pH (or high acidity) at the surfaces of cells within the tumor microenvironment (TME) as a targeted biomarker. pHLIPs can be used for extracellular and intracellular delivery of a variety of imaging and therapeutic payloads. Unlike therapeutic delivery targeted to specific receptors on the surfaces of particular cells, pHLIP targets cancer, stromal and some immune cells all at once. Since the TME exhibits complex cellular crosstalk interactions, simultaneous targeting and delivery to different cell types leads to a significant synergistic effect for many agents. pHLIPs can also be positioned on the surfaces of various nanoparticles (NPs) for the targeted intracellular delivery of encapsulated payloads. The pHLIP technology is currently advancing in pre-clinical and clinical applications for tumor imaging and treatment.
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- 2024
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4. Arginine Residues Modulate the Membrane Interactions of pHLIP Peptides.
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Tomás F. D. Silva, Hannah Visca, Craig Klumpp, Oleg A. Andreev, Yana K. Reshetnyak, and Miguel Machuqueiro
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- 2023
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5. Targeting acidic pre-metastatic niche in lungs by pH low insertion peptide and its utility for anti-metastatic therapy
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Toma Matsui, Yuki Toda, Haruka Sato, Rina Itagaki, Kazuya Konishi, Anna Moshnikova, Oleg A. Andreev, Shigekuni Hosogi, Yana K. Reshetnyak, and Eishi Ashihara
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extracellular acidity ,pre-metastatic niche ,pH low insertion peptide ,metabolic reprogramming ,extracellular vesicle ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Dysregulated extracellular pH, the universal feature of tumor, works as an evolutional force to drive dissemination of tumor cells. It is well-established that tumor acidity is associated with tumor growth and metastasis. However, the pH of pre-metastatic niche remains unclear. We hypothesized that primary tumor cells remotely prime acidity in secondary organ to achieve metastatic colonization. Herein, we demonstrated that the pH responsive probe pH Low Insertion Peptide (pHLIP) was notably accumulated in pre-metastatic lungs of 4T1.2 breast tumor-bearing mice. The pHLIP-targeted lungs showed high amounts of lactate and overexpressed glycolysis-related proteins. Pharmacological inhibition of glycolysis suppressed the lung acidification induced by 4T1.2 cancer cell culture supernatant and delayed subsequent metastatic burden of disseminated tumor cells. In the acidic lungs, pHLIP was primarily localized in alveolar type 2 cells which strongly expressed glycolysis-related proteins. 4T1.2-derived extracellular vesicles expressed some of the glycolysis-related proteins, and their administration increased pHLIP accumulation and glycolytic enhancement in lungs. pHLIP-conjugated dexamethasone effectively attenuated lung metastatic burden by disrupting pro-inflammatory response in the acidic lungs. From these results, targeting the metastasis-supporting microenvironment by pHLIP technology creates possibility to identify pre-metastatic organ and prevent metastatic recurrence.
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- 2023
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6. Tumor treatment by pHLIP-targeted antigen delivery
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Michael DuPont, Hannah Visca, Anna Moshnikova, Donald M. Engelman, Yana K. Reshetnyak, and Oleg A. Andreev
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cancer therapeutic vaccine ,tumor acidity ,immunization ,HA peptide ,alpha-gal ,epitopes ,Biotechnology ,TP248.13-248.65 - Abstract
Targeted antigen delivery allows activation of the immune system to kill cancer cells. Here we report the targeted delivery of various epitopes, including a peptide, a small molecule, and a sugar, to tumors by pH Low Insertion Peptides (pHLIPs), which respond to surface acidity and insert to span the membranes of metabolically activated cancer and immune cells within tumors. Epitopes linked to the extracellular ends of pH Low Insertion Peptide peptides were positioned at the surfaces of tumor cells and were recognized by corresponding anti-epitope antibodies. Special attention was devoted to the targeted delivery of the nine residue HA peptide epitope from the Flu virus hemagglutinin. The HA sequence is not present in the human genome, and immunity is readily developed during viral infection or immunization with KLH-HA supplemented with adjuvants. We tested and refined a series of double-headed HA-pHLIP agents, where two HA epitopes were linked to a single pH Low Insertion Peptide peptide via two Peg12 or Peg24 polymers, which enable HA epitopes to engage both antibody binding sites. HA-epitopes positioned at the surfaces of tumor cells remain exposed to the extracellular space for 24–48 h and are then internalized. Different vaccination schemes and various adjuvants, including analogs of FDA approved adjuvants, were tested in mice and resulted in a high titer of anti-HA antibodies. Anti-HA antibody binds HA-pHLIP in blood and travels as a complex leading to significant tumor targeting with no accumulation in organs and to hepatic clearance. HA-pHLIP agents induced regression of 4T1 triple negative breast tumor and B16F10 MHC-I negative melanoma tumors in immunized mice. The therapeutic efficacy potentially is limited by the drop of the level of anti-HA antibodies in the blood to background level after three injections of HA-pHLIP. We hypothesize that additional boosts would be required to keep a high titer of anti-HA antibodies to enhance efficacy. pH Low Insertion Peptide-targeted antigen therapy may provide an opportunity to treat tumors unresponsive to T cell based therapies, having a small number of neo-antigens, or deficient in MHC-I presentation at the surfaces of cancer cells either alone or in combination with other approaches.
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- 2023
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7. Eradication of tumors and development of anti-cancer immunity using STINGa targeted by pHLIP
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Anna Moshnikova, Michael DuPont, Hannah Visca, Donald M. Engelman, Oleg A. Andreev, and Yana K. Reshetnyak
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immunotherapy ,tumor acidity ,tumor pH ,tumor stroma ,targeted STINGa ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Despite significant progress in the development of novel STING agonists (STINGa), applications appear to be challenged by the low efficiency and poor selectivity of these agents. A pH Low Insertion Peptide (pHLIP) extends the lifetime of a STINGa in the blood and targets it to acidic cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), myeloid derived suppressor cells (mMDSCs) and dendritic cells (DCs). CAFs constitute 25% of all live cells within CT26 tumors, and M2-type TAMs and mMDSCs are the most abundant among the immune cells. The resulting activation of cytokines within the tumor microenvironment (TME) triggers the eradication of small (100 mm3) and large (400-700 mm3) CT26 tumors in mice after a single dose of pHLIP-STINGa. The tumor stroma was destroyed (the number of CAFs was reduced by 98%), intratumoral hemorrhage developed, and the level of acidity within the TME was reduced. Further, no tumors developed in 20 out of 25 tumor-free mice re-challenged by an additional injection of cancer cells. The therapeutic effect on CT26 tumors was insignificant in nude mice, lacking T-cells. Thus, targeted delivery of STINGa to tumor stroma and TAMs induces activation of signaling, potentially resulting in the recruitment and infiltration of T-cells, which gain access to the tumor core. The cytotoxic activity of T-cells is not impaired by an acidic environment and immune memory is developed.
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- 2022
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8. Magnetic, Optical, and Thermic Properties of SrLnCuSe3 (Ln = Dy, Ho, Er, Tm) Compounds
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Navruzbek N. Habibullayev, Nikolay G. Naumov, Alexander N. Lavrov, Natalia V. Kuratieva, Aleksandr S. Aleksandrovsky, Aleksandr S. Oreshonkov, Maxim S. Molokeev, Irina V. Palamarchuk, Ilya O. Yurev, Yuriy G. Denisenko, Oleg V. Andreev, and Alena D. Zakharova
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single-crystal X-ray diffraction ,Curie–Weiss dependence ,magnetic susceptibility ,effective magnetic momentum ,bandgap ,DFT calculations ,Chemistry ,QD1-999 - Abstract
SrLnCuSe3 (Ln = Dy, Ho, Er, Tm) compounds crystallize in the Pnma and Cmcm orthorhombic space group and belong to the Eu2CuS3 and KCuZrS3 structural type, respectively. According to a single-crystal XRD study, the SrTmCuSe3 unit cell parameters are a = 4.0631 (4), b = 13.4544 (14), c = 10.4430 (10) Å, and V = 570.88 (10) Å3. All the studied SrLnCuSe3 samples in the temperature range of 1.77–300 K demonstrate paramagnetic behavior without any features pointing to magnetic ordering. The measured Curie constants coincide with the values expected for Ln3+ ions with good accuracy, which confirms the stoichiometric composition of the samples and the non-magnetic state of the copper ions, Cu1+ (S = 0). The conducted optical absorption study showed that the polycrystalline SrLnCuSe3 (Ln = Dy, Ho, Er, Tm) samples are semiconductors with a direct bandgap ranging from 2.14 eV to 2.31 eV. Two indirect bandgaps were revealed and explained by the presence of optical transitions to highly dispersive subbands in the conduction band. The compounds demonstrate two reversible phase transitions α⇆β, β⇆γ and an incongruent melting at 1606 K (Dy), 1584 K (Ho), 1634 K (Er), and 1620 K (Tm) associated with the formation of solid solutions of SrSe, Cu2-XSe, and Ln2Se3 binary compounds.
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- 2023
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9. Kinetics and Mechanism of BaLaCuS3 Oxidation
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Nikita O. Azarapin, Nikolay A. Khritokhin, Victor V. Atuchin, Alexey A. Gubin, Maxim S. Molokeev, Shaibal Mukherjee, and Oleg V. Andreev
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BaLaCuS3 ,complex sulfide ,oxidation ,kinetic ,XRD analysis ,Crystallography ,QD901-999 - Abstract
The oxidation reactions of BaLaCuS3 in the artificial air atmosphere were studied at different heating rates in the temperature range of 50–1200 °C. The oxidation stages were determined by DSC-TG, XRD and IR–vis methods. The kinetic characteristics of the proceeding reactions were obtained with the use of the Kissinger model in a linearized form. Compound BaLaCuS3 was stable in the air up to 280 °C. Upon further heating up to 1200 °C, this complex sulfide underwent three main oxidation stages. The first stage is the formation of BaSO4 and CuLaS2. The second stage is the oxidation of CuLaS2 to La2O2SO4 and copper oxides. The third stage is the destruction of La2O2SO4. The final result of the high-temperature treatment in the artificial air atmosphere was a mixture of barium sulfate, copper (II) oxide and La2CuO4. The mechanism and stages of BaLaCuS3 oxidation and further interactions of the components were discussed.
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- 2023
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10. T-cells produce acidic niches in lymph nodes to suppress their own effector functions
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Hao Wu, Veronica Estrella, Matthew Beatty, Dominique Abrahams, Asmaa El-Kenawi, Shonagh Russell, Arig Ibrahim-Hashim, Dario Livio Longo, Yana K. Reshetnyak, Anna Moshnikova, Oleg A. Andreev, Kimberly Luddy, Mehdi Damaghi, Krithika Kodumudi, Smitha R. Pillai, Pedro Enriquez-Navas, Shari Pilon-Thomas, Pawel Swietach, and Robert J. Gillies
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Science - Abstract
T-cell activation primarily occurs in the lymph nodes, highly organized and specialized secondary lymphoid organs. Here the authors show that the acidic extracellular pH in lymph node paracortical zones limits cytokine production by effector T-cells, but does not alter their activation by antigen-presenting cells.
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- 2020
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11. PET Imaging of Acidic Tumor Environment With 89Zr-labeled pHLIP Probes
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David Bauer, Hannah Visca, Anuradha Weerakkody, Lukas M. Carter, Zachary Samuels, Spencer Kaminsky, Oleg A. Andreev, Yana K. Reshetnyak, and Jason S. Lewis
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pH-low insertion peptides ,membrane-insertion behavior ,acidic tumor microenvironment ,zirconium-89 ,PET imaging ,human dosimetry estimates ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Acidosis of the tumor microenvironment is a hallmark of tumor progression and has emerged as an essential biomarker for cancer diagnosis, prognosis, and evaluation of treatment response. A tool for quantitatively visualizing the acidic tumor environment could significantly advance our understanding of the behavior of aggressive tumors, improving patient management and outcomes. 89Zr-labeled pH-low insertion peptides (pHLIP) are a class of radiopharmaceutical imaging probes for the in vivo analysis of acidic tumor microenvironments via positron emission tomography (PET). Their unique structure allows them to sense and target acidic cancer cells. In contrast to traditional molecular imaging agents, pHLIP’s mechanism of action is pH-dependent and does not rely on the presence of tumor-specific molecular markers. In this study, one promising acidity-imaging PET probe ([89Zr]Zr-DFO-Cys-Var3) was identified as a candidate for clinical translation.
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- 2022
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12. Exploration of the Crystal Structure and Thermal and Spectroscopic Properties of Monoclinic Praseodymium Sulfate Pr2(SO4)3
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Yuriy G. Denisenko, Victor V. Atuchin, Maxim S. Molokeev, Alexander E. Sedykh, Nikolay A. Khritokhin, Aleksandr S. Aleksandrovsky, Aleksandr S. Oreshonkov, Nikolai P. Shestakov, Sergey V. Adichtchev, Alexey M. Pugachev, Elena I. Sal’nikova, Oleg V. Andreev, Illaria A. Razumkova, and Klaus Müller-Buschbaum
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praseodymium sulfate ,crystal structure ,thermal analysis ,thermal expansion anisotropy ,photoluminescence ,band structure ,Organic chemistry ,QD241-441 - Abstract
Praseodymium sulfate was obtained by the precipitation method and the crystal structure was determined by Rietveld analysis. Pr2(SO4)3 is crystallized in the monoclinic structure, space group C2/c, with cell parameters a = 21.6052 (4), b = 6.7237 (1) and c = 6.9777 (1) Å, β = 107.9148 (7)°, Z = 4, V = 964.48 (3) Å3 (T = 150 °C). The thermal expansion of Pr2(SO4)3 is strongly anisotropic. As was obtained by XRD measurements, all cell parameters are increased on heating. However, due to a strong increase of the monoclinic angle β, there is a direction of negative thermal expansion. In the argon atmosphere, Pr2(SO4)3 is stable in the temperature range of T = 30–870 °C. The kinetics of the thermal decomposition process of praseodymium sulfate octahydrate Pr2(SO4)3·8H2O was studied as well. The vibrational properties of Pr2(SO4)3 were examined by Raman and Fourier-transform infrared absorption spectroscopy methods. The band gap structure of Pr2(SO4)3 was evaluated by ab initio calculations, and it was found that the valence band top is dominated by the p electrons of oxygen ions, while the conduction band bottom is formed by the d electrons of Pr3+ ions. The exact position of ZPL is determined via PL and PLE spectra at 77 K to be at 481 nm, and that enabled a correct assignment of luminescent bands. The maximum luminescent band in Pr2(SO4)3 belongs to the 3P0 → 3F2 transition at 640 nm.
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- 2022
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13. Targeting Acidic Diseased Tissues by pH-Triggered Membrane-Associated Peptide Folding
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Yana K. Reshetnyak, Anna Moshnikova, Oleg A. Andreev, and Donald M. Engelman
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cancer ,inflammation ,imaging ,therapy ,pHLIP ,fluorescence ,Biotechnology ,TP248.13-248.65 - Abstract
The advantages of targeted therapy have motivated many efforts to find distinguishing features between the molecular cell surface landscapes of diseased and normal cells. Typically, the features have been proteins, lipids or carbohydrates, but other approaches are emerging. In this discussion, we examine the use of cell surface acidity as a feature that can be exploited by using pH-sensitive peptide folding to target agents to diseased cell surfaces or cytoplasms.
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- 2020
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14. Decoration of Nanovesicles with pH (Low) Insertion Peptide (pHLIP) for Targeted Delivery
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Federica Rinaldi, Patrizia N. Hanieh, Elena Del Favero, Valeria Rondelli, Paola Brocca, Mohan C. Pereira, Oleg A. Andreev, Yana K. Reshetnyak, Carlotta Marianecci, and Maria Carafa
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pHLIP ,Liposomes ,Niosomes ,pH-sensitivity ,Cryo-TEM ,SAXS ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Abstract Acidity at surface of cancer cells is a hallmark of tumor microenvironments, which does not depend on tumor perfusion, thus it may serve as a general biomarker for targeting tumor cells. We used the pH (low) insertion peptide (pHLIP) for decoration of liposomes and niosomes. pHLIP senses pH at the surface of cancer cells and inserts into the membrane of targeted cells, and brings nanomaterial to close proximity of cellular membrane. DMPC liposomes and Tween 20 or Span 20 niosomes with and without pHLIP in their coating were fully characterized in order to obtain fundamental understanding on nanocarrier features and facilitate the rational design of acidity sensitive nanovectors. The samples stability over time and in presence of serum was demonstrated. The size, ζ-potential, and morphology of nanovectors, as well as their ability to entrap a hydrophilic probe and modulate its release were investigated. pHLIP decorated vesicles could be useful to obtain a prolonged (modified) release of biological active substances for targeting tumors and other acidic diseased tissues.
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- 2018
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15. Synthesis, Structure, and Properties of EuLnCuSe3 (Ln = Nd, Sm, Gd, Er)
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Oleg V. Andreev, Victor V. Atuchin, Alexander S. Aleksandrovsky, Yuriy G. Denisenko, Boris A. Zakharov, Alexander P. Tyutyunnik, Navruzbek N. Habibullayev, Dmitriy A. Velikanov, Dmitriy A. Ulybin, and Daniil D. Shpindyuk
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rare earth elements ,complex sulfides ,chalcogenides ,crystal structure ,magnetic properties ,Crystallography ,QD901-999 - Abstract
EuLnCuSe3 (Ln = Nd, Sm, Gd, Er), due to their complex composition, should be considered new materials with the ability to purposefully change the properties. Samples of the EuLnCuSe3 were prepared using Cu, rare earth metal, Se (99.99%) by the ampoule method. The samples were obtained by the crystallization from a melt and annealed at temperatures 1073 and 1273 K. The EuErCuSe3 crystal structure was established using the single-crystal particle. EuErCuSe3 crystallizes in the orthorhombic system, space group Cmcm, KCuZrS3 structure type, with cell parameters a = 4.0555 (3), b = 13.3570 (9), and c = 10.4602 (7) Å, V = 566.62 (6) Å3. In structure EuErCuSe3, erbium ions are coordinated by selenium ions in the octahedral polyhedron, copper ions are in the tetrahedral coordination, europium ions are between copper and erbium polyhedra layers and are coordinated by selenium ions as two-cap trigonal prisms. The optical band gap is 1.79 eV. At 4.7 K, a transition from the ferrimagnetic state to the paramagnetic state was detected in EuErCuSe3. At 85 and 293 K, the compound is in a paramagnetic state. According to XRPD data, EuLnCuSe3 (Ln = Nd, Sm, Gd) compounds have a Pnma orthorhombic space group of the Eu2CuS3 structure type. For EuSmCuSe3, a = 10.75704 (15) Å, b = 4.11120 (5) Å, c = 13.37778 (22) Å. In the series of EuLnCuSe3 compounds, the optical band gap increases 1.58 eV (Nd), 1.58 eV (Sm), 1.72 eV (Gd), 1.79 eV (Er), the microhardness of the 205 (Nd), 210 (Sm), 225 (Gd) 235 ± 4 HV (Er) phases increases, and the thermal stability of the phases increases significantly. According to the measurement data of differential scanning calorimetry, the EuNdCuSe3 decomposes, according to the solid-phase reaction T = 1296 K, ΔH = 8.2 ± 0.8 kJ/mol. EuSmCuSe3 melts incongruently T = 1449 K, ΔH = 18.8 ± 1.9 kJ/mol. For the EuGdCuSe3, two (Tα↔β = 1494 K, ΔHα↔β = 14.8 kJ/mol, Tβ↔γ = 1530 K, ΔHβ↔γ = 4.8 kJ/mol) and for EuErCuSe3 three polymorphic transitions (Tα↔β = 1561 K, ΔHα↔β = 30.3 kJ/mol, Tβ↔γ = 1579 K, ΔHβ↔γ = 4.4 kJ/mol, and Tγ↔δ = 1600 K, ΔHγ↔δ = 10.1 kJ/mol). The compounds melt incongruently at the temperature of 1588 K, ΔHmelt = 17.9 ± 1.8 kJ/mol and 1664 K, ΔHmelt = 25.6 ± 2.5 kJ/mol, respectively. Incongruent melting of the phases proceeds with the formation of a solid solution of EuSe and a liquid phase.
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- 2021
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16. Synthesis and characterization of pHLIP® coated gold nanoparticles
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Jennifer L. Daniels, Troy M. Crawford, Oleg A. Andreev, and Yana K. Reshetnyak
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Spherical gold nanoparticles ,Spiked gold nanoparticles ,Disk-like bicelles ,Hyperthermia ,Tumor targeting ,Acidity ,Biology (General) ,QH301-705.5 ,Biochemistry ,QD415-436 - Abstract
Novel approaches in synthesis of spherical and multispiked gold nanoparticles coated with polyethylene glycol (PEG) and pH Low Insertion Peptide (pHLIP®) were introduced. The presence of a tumor-targeting pHLIP® peptide in the nanoparticle coating enhances the stability of particles in solution and promotes a pH-dependent cellular uptake. The spherical particles were prepared with sodium citrate as a gold reducing agent to form particles of 7.0±2.5 nm in mean metallic core diameter and ∼43 nm in mean hydrodynamic diameter. The particles that were injected into tumors in mice (21 µg of gold) were homogeneously distributed within a tumor mass with no staining of the muscle tissue adjacent to the tumor. Up to 30% of the injected gold dose remained within the tumor one hour post-injection. The multispiked gold nanoparticles with a mean metallic core diameter of 146.0±50.4 nm and a mean hydrodynamic size of ~161 nm were prepared using ascorbic acid as a reducing agent and disk-like bicelles as a template. Only the presence of a soft template, like bicelles, ensured the appearance of spiked nanoparticles with resonance in the near infrared region. The irradiation of spiked gold nanoparticles by an 805 nm laser led to the time- and concentration-dependent increase of temperature. Both pHLIP® and PEG coated gold spherical and multispiked nanoparticles might find application in radiation and thermal therapies of tumors.
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- 2017
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17. Crystal Structure, Vibrational, Spectroscopic and Thermochemical Properties of Double Sulfate Crystalline Hydrate [CsEu(H2O)3(SO4)2]·H2O and Its Thermal Dehydration Product CsEu(SO4)2
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Yuriy G. Denisenko, Maxim S. Molokeev, Aleksandr S. Oreshonkov, Alexander S. Krylov, Aleksandr S. Aleksandrovsky, Nikita O. Azarapin, Oleg V. Andreev, Illaria A. Razumkova, and Victor V. Atuchin
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sulfate ,dehydration ,crystal structure ,Raman ,thermal stability ,photoluminescence ,Crystallography ,QD901-999 - Abstract
Crystalline hydrate of double cesium europium sulfate [CsEu(H2O)3(SO4)2]·H2O was synthesized by the crystallization from an aqueous solution containing equimolar amounts of 1Cs+:1Eu3+:2SO42− ions. Anhydrous salt CsEu(SO4)2 was formed as a result of the thermal dehydration of the crystallohydrate. The unusual effects observed during the thermal dehydration were attributed to the specific coordination of water molecules in the [CsEu(H2O)3(SO4)2]·H2O structure. The crystal structure of [CsEu(H2O)3(SO4)2]·H2O was determined by a single crystal X-ray diffraction analysis, and the crystal structure of CsEu(SO4)2 was obtained by the Rietveld method. [CsEu(H2O)3(SO4)2]·H2O crystallizes in the monoclinic system, space group P21/c (a = 6.5574(1) Å, b = 19.0733(3) Å, c = 8.8364(2) Å, β = 93.931(1)°, V = 1102.58(3) Å3). The anhydrous sulfate CsEu(SO4)2 formed as a result of the thermal destruction crystallizes in the monoclinic system, space group C2/c (a = 14.327(1) Å, b = 5.3838(4) Å, c = 9.5104(6) Å, β = 101.979(3) °, V = 717.58(9) Å3). The vibration properties of the compounds are fully consistent with the structural models and are mainly determined by the deformation of non-rigid structural elements, such as H2O and SO42−. As shown by the diffused reflection spectra measurements and DFT calculations, the structural transformation from [CsEu(H2O)3(SO4)2]·H2O to CsEu(SO4)2 induced a significant band gap reduction. A noticeable difference of the luminescence spectra between cesium europium sulfate and cesium europium sulfate hydrate is detected and explained by the variation of the extent of local symmetry violation at the crystallographic sites occupied by Eu3+ ions, namely, by the increase in inversion asymmetry in [CsEu(H2O)3(SO4)2]·H2O and the increase in mirror asymmetry in CsEu(SO4)2. The chemical shift of the 5D0 energy level in cesium europium sulfate hydrate, with respect to cesium europium sulfate, is associated with the presence of H2O molecules in the vicinity of Eu3+ ion.
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- 2021
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18. Targeted Suppression of miRNA-33 Using pHLIP Improves Atherosclerosis Regression
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Xinbo Zhang, Noemi Rotllan, Alberto Canfrán-Duque, Jonathan Sun, Jakub Toczek, Anna Moshnikova, Shipra Malik, Nathan L. Price, Elisa Araldi, Wen Zhong, Mehran M. Sadeghi, Oleg A. Andreev, Raman Bahal, Yana K. Reshetnyak, Yajaira Suárez, and Carlos Fernández-Hernando
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MicroRNAs ,Physiology ,Macrophages ,Antagomirs ,Humans ,Atherosclerosis ,Cardiology and Cardiovascular Medicine ,Article ,Plaque, Atherosclerotic - Abstract
Background: miRNA therapeutics have gained attention during the past decade. These oligonucleotide treatments can modulate the expression of miRNAs in vivo and could be used to correct the imbalance of gene expression found in human diseases such as obesity, metabolic syndrome, and atherosclerosis. The in vivo efficacy of current anti-miRNA technologies hindered by physiological and cellular barriers to delivery into targeted cells and the nature of miRNAs that allows one to target an entire pathway that may lead to deleterious off-target effects. For these reasons, novel targeted delivery systems to inhibit miRNAs in specific tissues will be important for developing effective therapeutic strategies for numerous diseases including atherosclerosis. Methods: We used pH low-insertion peptide (pHLIP) constructs as vehicles to deliver microRNA-33-5p (miR-33) antisense oligonucleotides to atherosclerotic plaques. Immunohistochemistry and histology analysis was performed to assess the efficacy of miR-33 silencing in atherosclerotic lesions. We also assessed how miR-33 inhibition affects gene expression in monocytes/macrophages by single-cell RNA transcriptomics. Results: The anti-miR-33 conjugated pHLIP constructs are preferentially delivered to atherosclerotic plaque macrophages. The inhibition of miR-33 using pHLIP-directed macrophage targeting improves atherosclerosis regression by increasing collagen content and decreased lipid accumulation within vascular lesions. Single-cell RNA sequencing analysis revealed higher expression of fibrotic genes ( Col2a1, Col3a1, Col1a2, Fn1 , etc) and tissue inhibitor of metalloproteinase 3 ( Timp3 ) and downregulation of Mmp12 in macrophages from atherosclerotic lesions targeted by pHLIP-anti-miR-33. Conclusions: This study provides proof of principle for the application of pHLIP for treating advanced atherosclerosis via pharmacological inhibition of miR-33 in macrophages that avoid the deleterious effects in other metabolic tissues. This may open new therapeutic opportunities for atherosclerosis-associated cardiovascular diseases via selective delivery of other protective miRNAs.
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- 2022
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19. pHLIP Peptides Target Acidity in Activated Macrophages
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Hannah Visca, Michael DuPont, Anna Moshnikova, Troy Crawford, Donald M. Engelman, Oleg A. Andreev, and Yana K. Reshetnyak
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Lipopolysaccharides ,Mice ,Cancer Research ,Drug Delivery Systems ,Oncology ,Neoplasms ,Macrophages ,Tumor Microenvironment ,Animals ,Radiology, Nuclear Medicine and imaging ,Hydrogen-Ion Concentration ,Peptides - Abstract
Acidity can be a useful alternative biomarker for the targeting of metabolically active cells in certain diseased tissues, as in acute inflammation or aggressive tumors. We investigated the targeting of activated macrophages by pH low insertion peptides (pHLIPs), an established technology for targeting cell-surface acidity.The uptake of fluorescent pHLIPs by activated macrophages was studied in cell cultures, in a mouse model of lung inflammation, and in a mouse tumor model. Fluorescence microscopy, whole-body and organ imaging, immunohistochemistry, and FACS analysis were employed.We find that cultured, activated macrophages readily internalize pHLIPs. The uptake is higher in glycolytic macrophages activated by LPS and INF-γ compared to macrophages activated by IL-4/IL-13. Fluorescent pHLIPs target LPS-induced lung inflammation in mice. In addition to marking cancer cells within the tumor microenvironment, fluorescent pHLIPs target CD45pHLIP peptides sense low cell surface pH, which triggers their insertion into the cell membrane. Unlike cancerous cells, activated macrophages do not retain inserted pHLIPs on their surfaces, instead their highly active membrane recycling moves the pHLIPs into endosomes. Targeting activated macrophages in diseased tissues may enable clinical visualization and therapeutic opportunities.
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- 2022
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20. Exploration of the structural, spectroscopic and thermal properties of double sulfate monohydrate NaSm(SO4)2·H2O and its thermal decomposition product NaSm(SO4)2
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Aleksandr S. Aleksandrovsky, Alexander S. Krylov, Victor V. Atuchin, Yuriy G. Denisenko, Oleg V. Andreev, Sofia A. Basova, Aleksandr S. Oreshonkov, E.I. Sal’nikova, Maxim S. Molokeev, Alexander E. Sedykh, Klaus Müller-Buschbaum, and Nikolay A. Khritokhin
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chemistry.chemical_classification ,Materials science ,General Chemical Engineering ,Thermal decomposition ,Salt (chemistry) ,Crystal structure ,Triclinic crystal system ,law.invention ,chemistry.chemical_compound ,chemistry ,Mechanics of Materials ,law ,Anhydrous ,Physical chemistry ,Crystallization ,Sulfate ,Hydrate - Abstract
Samarium-sodium double sulfate crystalline hydrate NaSm(SO4)2·H2O was obtained by the crystallization from an aqueous solution containing equimolar amounts of ions. The anhydrous salt of NaSm(SO4)2 was formed by a thermally induced release of the equivalent of water from NaSm(SO4)2·H2O. The kinetic parameters of thermal decomposition were determined (Ea = 102 kJ/mol, A = 9·106). The crystal structures of both compounds were refined from the X-ray powder diffraction data. Sulfate hydrate NaSm(SO4)2·H2O crystallizes in the trigonal symmetry, space group P3121 (a = 6.91820(3) and c = 12.8100(1) A, V = 530.963(7) A3). The anhydrous salt crystallizes in the triclinic symmetry, space group P-1 (a = 6.8816(2), b = 6.2968(2) and c = 7.0607(2) A, α = 96.035(1), β = 99.191(1) and γ = 90.986(1)°, V = 300.17(1) A3). The vibrational properties of compounds are mainly determined by the sulfate group deformations. The luminescence spectra of both sulfates are similar and are governed by the transitions of samarium ions 4G5/2 → 6HJ (J = 5/2, 7/2, 9/2 and 11/2). The anhydrous sulfate is stable up to 1100 K and undergoes an almost isotropic expansion when heated. After 1100 K, the compound decomposes into Sm2(SO4)3 and Na2SO4.
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- 2021
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21. Evolution of Structural, Thermal, Optical, and Vibrational Properties of Sc 2 S 3 , ScCuS 2 , and BaScCuS 3 Semiconductors
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Aleksandr S. Oreshonkov, Illaria A. Razumkova, Nikita O. Azarapin, Ivan I. Leonidov, Nikolai G. Maximov, N.P. Shestakov, Aleksandr S. Aleksandrovsky, and Oleg V. Andreev
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Inorganic Chemistry ,Semiconductor ,business.industry ,Chemistry ,Chemical physics ,Thermal ,business - Published
- 2021
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22. Negative thermal expansion in one-dimension of a new double sulfate AgHo(SO4)2 with isolated SO4 tetrahedra
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Zheshuai Lin, Klaus Müller-Buschbaum, Yuriy G. Denisenko, Alexander E. Sedykh, Naizheng Wang, Maxim S. Molokeev, Xingxing Jiang, Victor V. Atuchin, Oleg V. Andreev, Aleksandr S. Aleksandrovsky, Alexander S. Krylov, Aleksandr S. Oreshonkov, and Svetlana S. Volkova
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Materials science ,Polymers and Plastics ,Infrared ,Mechanical Engineering ,Metals and Alloys ,Analytical chemistry ,02 engineering and technology ,Crystal structure ,Atmospheric temperature range ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Thermal expansion ,0104 chemical sciences ,Crystal ,Negative thermal expansion ,Mechanics of Materials ,Materials Chemistry ,Ceramics and Composites ,0210 nano-technology ,Luminescence ,Monoclinic crystal system - Abstract
A double holmium-silver sulfate was obtained for the first time. The temperature intervals for the formation and stability of the compound were determined by differential scanning calorimetry. The crystal structure of AgHo(SO4)2 was determined by Rietveld method. The X-ray diffraction (XRD) analysis showed that the compound crystallizes in the monoclinic syngony, space group P21/m, with the unit cell parameters a = 4.71751 (4) A, b = 6.84940 (6) A and c = 9.89528 (9) A, β = 95.1466 (4)°, V = 318.448 (5) A3, Z = 2, RB = 1.55 %, T = 303 K. Two types of sulfate tetrahedra were found in the structure, which significantly affected the spectral properties in the infrared range. In the temperature range of 143−703 K, a negative thermal expansion along the b direction accompanied by a positive thermal expansion along the a and c directions was observed. It was established that negative thermal expansion is the result of the deformation of sulfate tetrahedra, which is affected by the movement of holmium and silver atoms. The excitation in the blue spectral range (457.9 nm) produces a luminescence in light blue (489 nm), green (545 nm) and red (654 nm) spectral ranges, and the latter two were of comparable intensity that is favorable for WLED sources. The observed luminescent band distribution is ascribed to the specific crystal field at Ho3+ ion sites rather than a variation of radiationless probability.
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- 2021
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23. MnS–Tb2S3 Phase Diagram
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Oleg V. Andreev, Lyudmila N. Monina, and Irina G. Zhikhareva
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010302 applied physics ,Materials science ,Diagram ,0211 other engineering and technologies ,Metals and Alloys ,Thermodynamics ,02 engineering and technology ,Liquidus ,Condensed Matter Physics ,01 natural sciences ,Decomposition ,0103 physical sciences ,Thermal ,Materials Chemistry ,Solubility ,021102 mining & metallurgy ,Phase diagram ,Eutectic system ,Solid solution - Abstract
The MnS–Tb2S3 phase diagram has been plotted by using physico-chemical methods of analysis. This diagram refers to the transition type from the eutectic system MnS–Gd2S3 to the systems with the formation of intermediate compounds. Two MnTb4S7 and MnTb2S4 complex sulfides are formed in the MnS–Tb2S3 system. The thermal effects of solid-phase decomposition of complex sulfides are as follows: ΔH = 27.4 kJ/mol at 1643 K for MnTb4S7 and ΔH = 16 kJ/mol at 1574 K for MnTb2S4. The solubility of MnS in γ-Tb2S3 at 1650 K is 16 mol.%, and 5 mol.% of MnS is dissolved in α-Tb2S3 at 1170 K. The solubility of Tb2S3 in α-MnS-based solid solution (SS) is 6 mol.% at 1650 K and 3 mol.% of Tb2S3 at 1170 K. The temperature of the γ-Tb2S3 solid solution eutectoid decomposition is equal to 1350 K, and the composition of the eutectoid is 87 mol.% of Tb2S3. The coordinates of the eutectic between MnS-based solid solution and γ-Tb2S3-based solid solution is assumed to be equal to 27 mol.% of Tb2S3 and 1666 K. Calculations of the liquidus line, carried out using the Van Laar's equation, are in agreement with the experimental data. The Gibbs excess partial energies are calculated for the MnS–Tb2S3 system, and their negative values are correlated with the formation of two complex sulfides MnTb2S4 and MnTb4S7 in the system.
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- 2021
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24. Targeting bladder urothelial carcinoma with pHLIP-ICG and inhibition of urothelial cancer cell proliferation by pHLIP-amanitin
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Anna Moshnikova, Borivoj Golijanin, Ali Amin, Joshua Doyle, Ohad Kott, Boris Gershman, Michael DuPont, Yujing Li, Xiongbin Lu, Donald M. Engelman, Oleg A. Andreev, Yana K. Reshetnyak, and Dragan Golijanin
- Subjects
Article - Abstract
Acidity is a useful biomarker for the targeting of metabolically active cells in tumors. pH Low Insertion Peptides (pHLIPs) sense the pH at the surfaces of tumor cells and can facilitate intracellular delivery of cell-permeable and cell-impermeable cargo molecules. In this study we have shown the targeting of malignant lesions in human bladders by fluorescent pHLIP agents, intracellular delivery of amanitin toxin by pHLIP for the inhibition of urothelial cancer cell proliferation, and enhanced potency of pHLIP-amanitin for cancer cells with 17p loss, a mutation frequently present in urothelial cancers. Twenty-eight ex-vivo bladder specimens, from patients undergoing robotic assisted laparoscopic radical cystectomy for bladder cancer, were treated via intravesical incubation for 15-60 minutes with pHLIP conjugated to indocyanine green (ICG) or IR-800 near infrared fluorescent (NIRF) dyes at concentrations of 4-8 μM. White light cystoscopy identified 47/58 (81%) and NIRF pHLIP cystoscopy identified 57/58 (98.3%) of malignant lesions of different subtypes and stages selected for histopathological processing. pHLIP NIRF imaging improved diagnosis by 17.3% (p < 0.05). All carcinoma-in-situ cases missed by white light cystoscopy were targeted by pHLIP agents and were diagnosed by NIRF imaging. We also investigated the interactions of pHLIP-amanitin with urothelial cancer cells of different grades. pHLIP-amanitin produced concentration- and pH-dependent inhibition of the proliferation of urothelial cancer cells treated for 2 hrs at concentrations up to 4 μM. A 3-4x enhanced cytotoxicity of pHLIP-amanitin was observed for cells with a 17p loss after 2 hrs of treatment at pH6. Potentially, pHLIP technology may improve the management of urothelial cancers, including imaging of malignant lesions using pHLIP-ICG for diagnosis and surgery, and the use of pHLIP-amanitin for treatment of superficial bladder cancers via intravesical instillation.
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- 2022
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25. MEMORIES OF BUILDERS OF DEFENSIVE FRONTIERS IN THE TERRITORY OF THE CHUVASH REPUBLIC DURING THE GREAT PATRIOTIC WAR AS A HISTORICAL SOURCE: GENERAL CHARACTERISTICS
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Oleg N. Shirokov, Marina A. Shirokova, and Oleg N. Andreev
- Abstract
The purpose of the study is to analyze a separate group of sources: memories and testimonies of participants in the events of constructing defensive frontiers in the territory of the ChASSR in 1941–1942, revealing their typical characteristics and assessment as a historical source. The scientific novelty consists in attracting new sources of personal character in the history of erecting defensive structures in the territory of Chuvashia in autumn-winter 1941–1942. As a result of the study, general, typical characteristics of memories and testimonies of participants of the historical event were revealed: the predominance of household details, emphasizing such conditions of the construction as transport accessibility of construction objects, weather conditions, accommodation of builders, supplying with products, workers’ interrelations, emotional saturation of the historical event perception, impact on verbal folklore.
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- 2020
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26. CURRENT TRENDS IN THE FUNCTIONING OF THE HIGHER EDUCATION SYSTEM WITHIN THE FRAMEWORK OF AN INNOVATIVE ECONOMY
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Larisa V. Ivanenko and Oleg S. Andreev
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Knowledge management ,Higher education ,business.industry ,Management system ,General Medicine ,Special Interest Group ,business ,Educational institution ,Human resources ,Human capital ,Commercialization ,Intellectual capital - Abstract
The proposed article considers the need to recognize the economic utility and social value of human resources, the development of which requires investment in comparison with other types of economic resources. The urgency of solving the problem of functioning of higher education system is dictated by the need to apply new approaches to the management of an educational institution. Successful companies focus their efforts on creating and developing a management system for educational institutions designed to work effectively with intellectual resources that are becoming less used today. All these circumstances explain the emergence of a special interest of scientists and practitioners in the management of intellectual capital and the effectiveness of the knowledge process. In this regard, there is a need for constant updating and change, which means that knowledge is always innovative. At the same time, the most interesting are the ways of transforming universities into a new type of organization focused on meeting the needs of the market, making a profit, developing innovative technologies, supporting high-tech research projects and managing them. Close interaction of business corporations with the University community, forms a diversified financial base, develops contacts with business, society and the state, and encourages the widespread use of initiative and support for innovation in the scientific and educational environment. The new conceptual approach has enriched the practice with progressive methods and technologies for managing people in a complex innovative environment. The priorities were flexible forms of labor use, continuous improvement of the quality of human resources, new approaches to organizing and stimulating labor, and addressing cultural and ethical factors of labor productivity and quality of life. The main components of scientific novelty are the regulation and mutual influence of the functioning infrastructure and the applied methodology of higher education.
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- 2020
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27. T-cells produce acidic niches in lymph nodes to suppress their own effector functions
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Dario Livio Longo, Arig Ibrahim-Hashim, Matthew Beatty, Mehdi Damaghi, Robert J. Gillies, Pedro M. Enriquez-Navas, Kimberly Luddy, Anna Moshnikova, Pawel Swietach, Shari Pilon-Thomas, Hao Wu, Dominique Abrahams, Shonagh Russell, Krithika Kodumudi, Veronica Estrella, Asmaa El-Kenawi, Smitha Pillai, Yana K. Reshetnyak, and Oleg A. Andreev
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0301 basic medicine ,CD4-Positive T-Lymphocytes ,Male ,Physiology ,medicine.medical_treatment ,Phosphofructokinase-1 ,General Physics and Astronomy ,02 engineering and technology ,CD8-Positive T-Lymphocytes ,Mice ,Glycolysis ,lcsh:Science ,Lymph node ,Mice, Knockout ,Mice, Inbred BALB C ,Multidisciplinary ,medicine.diagnostic_test ,Chemistry ,Effector ,Immunochemistry ,Hydrogen-Ion Concentration ,021001 nanoscience & nanotechnology ,Flow Cytometry ,tumor, acidosis, pH imaging, MRI, CEST ,pH imaging ,Cell biology ,medicine.anatomical_structure ,Cytokine ,acidosis ,Lymph ,0210 nano-technology ,CEST ,MRI ,Monocarboxylic Acid Transporters ,tumor ,Science ,Immunology ,General Biochemistry, Genetics and Molecular Biology ,Article ,Flow cytometry ,03 medical and health sciences ,Immune system ,medicine ,Extracellular ,Animals ,Cell Proliferation ,General Chemistry ,Mice, Inbred C57BL ,030104 developmental biology ,lcsh:Q ,Lymph Nodes - Abstract
The acidic pH of tumors profoundly inhibits effector functions of activated CD8 + T-cells. We hypothesize that this is a physiological process in immune regulation, and that it occurs within lymph nodes (LNs), which are likely acidic because of low convective flow and high glucose metabolism. Here we show by in vivo fluorescence and MR imaging, that LN paracortical zones are profoundly acidic. These acidic niches are absent in athymic Nu/Nu and lymphodepleted mice, implicating T-cells in the acidifying process. T-cell glycolysis is inhibited at the low pH observed in LNs. We show that this is due to acid inhibition of monocarboxylate transporters (MCTs), resulting in a negative feedback on glycolytic rate. Importantly, we demonstrate that this acid pH does not hinder initial activation of naïve T-cells by dendritic cells. Thus, we describe an acidic niche within the immune system, and demonstrate its physiological role in regulating T-cell activation., T-cell activation primarily occurs in the lymph nodes, highly organized and specialized secondary lymphoid organs. Here the authors show that the acidic extracellular pH in lymph node paracortical zones limits cytokine production by effector T-cells, but does not alter their activation by antigen-presenting cells.
- Published
- 2020
28. Europium (II) Sulfate EuSO 4 : Synthesis Methods, Crystal and Electronic Structure, Luminescence Properties
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Yuriy G. Denisenko, Alexander E. Sedykh, Aleksandr S. Oreshonkov, Maxim S. Molokeev, Nikita O. Azarapin, Elena I. Sal'nikova, Olga D. Chimitova, Oleg V. Andreev, Illaria A. Razumkova, and Klaus Müller‐Buschbaum
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Inorganic Chemistry - Published
- 2022
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29. Abstract 1804: Durable eradication of tumors by single injections of a pHLIP-STING agonist
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Donald M. Engelman, Yana K. Reshetnyak, and Oleg A. Andreev
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Cancer Research ,Oncology - Abstract
Purpose: pHLIPs (pH-Low Insertion Peptides) target cell surface acidity resulting from the metabolism of cells in a solid tumor. The acidity causes pHLIPs to insert as transmembrane helices, and attached cargoes can be delivered into targeted cells. STING agonists can trigger an immune response when they are inside cells. pHLIP targeted delivery of a STING agonist (STINGa) effectively triggers cytokine secretion to mobilize the immune system to eradicate tumors while avoiding side effects. Experimental Procedures: Constructs consisting of a pHLIP peptide (Var3) linked to a STINGa (diABZI) via a self-immolating linker were synthesized and characterized. Activation of the STING pathway by the agent was confirmed in cells. Small (100 mm3) and large (400-700 mm3) tumors were grown in female Balb/c mice following flank injections of CT26 colorectal cancer cells. Randomized groups of mice were injected i.p. or i.v. with pHLIP-STINGa made with L- or D- amino acid pHLIP peptides, STINGa alone, pHLIP alone or vehicle. Tumor size and body weight were then measured 3 times per week. The durability of the response to the agent was tested by a second injection of CT26 cells after 60 days. In separate experiments, the identities of targeted immune and stromal cells, the production of cytokines, the PK, tumor targeting and biodistribution were assessed. Results and Conclusions: pHLIP extends the lifetime of a STINGa in the blood 6-fold and delivers STINGa to acidic cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), myeloid derived suppressor cells (mMDSCs), and dendritic cells (DCs). The resulting activation of cytokines within the tumor microenvironment (TME) triggers the eradication of small and large CT26 tumors in mice after a single dose of pHLIP-STINGa. The tumor stroma was destroyed, intratumoral hemorrhage developed, and the TME pH increased, which is important for the efficient cytotoxic activity of immune cells. Further, no tumors developed in 20 out of 25 tumor-free mice re-challenged by an additional injection of cancer cells. The therapeutic effect on CT26 tumors was insignificant in nude mice lacking T-cells. Inhibition of MHC-I negative B16F10 melanoma tumor growth was also observed in Balb/c mice. Thus, targeted delivery of the STINGa to the tumor stroma and TAMs activates signaling, potentially resulting in the recruitment and infiltration of both T-cells and NK-cells, which gain access to the tumor core. The cytotoxic activity of immune cells is enhanced, and immune memory is developed. Citation Format: Donald M. Engelman, Yana K. Reshetnyak, Oleg A. Andreev. Durable eradication of tumors by single injections of a pHLIP-STING agonist [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1804.
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- 2023
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30. STEIGERUNG DER WETTBEWERBSFÄHIGKEIT VON INDUSTRIEUNTERNEHMEN DURCH DEN EINSATZ EINER CLUSTERSTRATEGIE
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Oleg Stanislavovich Andreev
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- 2022
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31. TARGETS AND NEW OPPORTUNITIES FOR THE FORMATION AND USE OF PERSONNEL IN THE MANAGEMENT OF THE ORGANIZATION IN THE CONTEXT OF DIGITAL TRANSFORMATION
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Antonina Leonardovna Lazutina, Tatiana Evgenevna Lebedeva, Polina Grigorevna Nikolenko, and Oleg Evgenevich Andreev
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- 2022
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32. Abstract B022: pH-low insertion peptide detects lactic acidosis contributing metastatic niche formation in lungs
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Toma Matsui, Yuki Toda, Anna Mosnikova, Oleg A. Andreev, Shigekuni Hosogi, Yana K. Reshetnyak, and Eishi Ashihara
- Subjects
Cancer Research ,Oncology - Abstract
Background: Pre-metastatic niche refers to the environment prepared for efficient colonization of disseminated cancer cells in specific organs. Primary tumor secretome facilitates pre-metastatic niche through a series of molecular and cellular changes. This study focuses on interstitial pH in organs with pre-metastatic niche because dysregulated pH homeostasis plays a well-established role in tumor metastasis. In primary tumor, extracellular acidification directly promotes invasion/migration of cancer cells for extravasation. Meanwhile, little is known regarding interstitial pH in organs that are distant from primary tumor. Methods: BALB/c mice were subcutaneously inoculated with 4T1.2 cells or 66cl4 cells (mouse breast cancer cell lines) with resistance against 6-thioguanine. Absence of metastatic cells in their lungs was confirmed by long-termed culture of dissociated pulmonary cells in presence of 6-thioguanine; it defines Day 21 from inoculation as a pre-metastatic phase. Alternatively, 4T1.2 cell-conditioned media (4T1.2-CM) or control media was intraperitoneally administered every day for 21 consecutive days. pH-low insertion peptide (pHLIP® peptide) stably labels cells exposed to acidic conditions, which is feasible to evaluate interstitial acidity in each organ. Alexa Fluor® 750-labelled pHLIP® peptide was injected into mice, and fluorescent signals in harvested organs were detected by IVIS Lumina XRMS Series III. For a metastasis model, mice first received 4T1.2-CM or in combination with sodium oxamate (a lactate dehydrogenase inhibitor) followed by an intravenous injection of 66cl4 cells expressing luciferase. Results: At the pre-metastatic phase, 4T1.2 tumor-bearing mice showed great accumulation of pHLIP® peptide and high amounts of lactate in their lungs. By contrast, there was no significant fluorescence from pHLIP® peptide in lungs of low-metastatic 66cl4 cell-inoculated mice. Notable accumulation of pHLIP® peptide was also observed in the lungs of 4T1.2-CM-given mice. Intravenously injected 66cl4 cells colonized more aggressively in the acidic lungs than in control ones. Suppression of the lung acidification by sodium oxamate attenuated the metastatic burden, which significantly improved survival of the mice. In the acidic lungs, pHLIP® peptide was localized in alveolar type II (AT2) cells expressing surfactant protein C. Sorted AT2 cells from the acidic lungs strongly expressed glycolysis-related proteins. Conclusions: This study using pHLIP® peptide indicates a highly glycolytic activity with increased lactic acid in the lungs of 4T1.2 tumor-bearing mice at the pre-metastatic phase. Mechanistically, soluble factors derived from 4T1.2 cells could transform AT2 cells into acidic cells, which might provide metastasis-promoting function. This study will shed light on understanding the whole picture of pre-metastatic niche and give scientific insights to develop novel diagnosis and therapy for tumor metastasis. Citation Format: Toma Matsui, Yuki Toda, Anna Mosnikova, Oleg A. Andreev, Shigekuni Hosogi, Yana K. Reshetnyak, Eishi Ashihara. pH-low insertion peptide detects lactic acidosis contributing metastatic niche formation in lungs [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B022.
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- 2023
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33. Correction to ‘Tumor-selective, antigen-independent delivery of a pH sensitive peptide-topoisomerase inhibitor conjugate suppresses tumor growth without systemic toxicity’
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Sophia Gayle, Robert Aiello, Nalin Leelatian, Jason M Beckta, Jane Bechtold, Patricia Bourassa, Johanna Csengery, Robert J Maguire, Dan Marshall, Ranjini K Sundaram, Jinny Van Doorn, Kelli Jones, Hunter Moore, Lori Lopresti-Morrow, Timothy Paradis, Laurie Tylaska, Qing Zhang, Hannah Visca, Yana K Reshetnyak, Oleg A Andreev, Donald M Engelman, Peter M Glazer, Ranjit S Bindra, and Vishwas M Paralkar
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- 2021
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34. FEATURES OF OPTIMIZING ROAD TRANSPORT ROUTES
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Oleg P. Andreev and Stanislav S. Doronin
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Transport engineering ,Road transport - Published
- 2020
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35. LAUNCHERS OF HEAT DISPOSAL WITH DEFROSTING SYSTEM
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Aleksey A. Putan and Oleg P. Andreev
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Waste management ,Defrosting ,Environmental science - Published
- 2020
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36. Synthesis and Upconversion Luminescence in LaF 3 :Yb 3+ , Ho 3+ , GdF 3 : Yb 3+ , Tm 3+ and YF 3 :Yb 3+ , Er 3+ obtained from Sulfide Precursors
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Andrey N. Boyko, Aleksandr S. Aleksandrovsky, Illariia A. Razumkova, Yuriy G. Denisenko, Oleg V. Andreev, D.A. Ikonnikov, and Nikita O. Azarapin
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Inorganic Chemistry ,chemistry.chemical_classification ,Sulfide ,Chemistry ,Upconversion luminescence ,GDF3 ,Photochemistry ,Photon upconversion ,Solid solution - Published
- 2019
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37. High-temperature oxidation of europium (II) sulfide
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Maxim S. Molokeev, Nikita O. Azarapin, E.I. Sal’nikova, Aleksandr S. Aleksandrovsky, Aleksandr S. Oreshonkov, Victor V. Atuchin, Alexander S. Krylov, Oleg V. Andreev, Yuriy G. Denisenko, and Pavel E. Plyusnin
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Materials science ,General Chemical Engineering ,Inorganic chemistry ,Enthalpy ,chemistry.chemical_element ,02 engineering and technology ,Atmospheric temperature range ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redox ,Oxygen ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Europium(II) sulfide ,0210 nano-technology ,Luminescence ,Europium - Abstract
The process of high-temperature oxidation of EuS in the air was explored in the temperature range of 500–1000 °C. The oxidation reaction enthalpy was determined (ΔH0exp = −1718.5 kJ/mol). The study of oxidation products allowed to establish the mechanism of EuS oxidation with oxygen. At 500–600 °C, EuS is oxidized to a mixture of Eu3+-containing compounds (Eu3S4, Eu2O2S). In the range of 700–1000 °C, only europium oxysulfate Eu2O2SO4 is formed. The structure refinement for Eu2O2SO4 was performed by the Rietveld method. The luminescence intensity of europium oxysulfate Eu2O2SO4 with characteristic 4f-4f transitions from the 5D0 state was investigated as a function of oxidation temperature.
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- 2019
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38. Crystal structure variations in the series SrLnCuS3 (Ln = La, Pr, Sm, Gd, Er and Lu)
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Leonid A. Solovyov, Oleg V. Andreev, Maksim V. Grigoriev, and Anna V. Ruseikina
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Inorganic Chemistry ,Diffraction ,PR/SM ,Crystallography ,Ionic radius ,Series (mathematics) ,Chemistry ,Materials Chemistry ,Structure type ,Crystal structure ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Powder diffraction - Abstract
The crystal structures of the complex sulfides SrLnCuS3 (Ln = Sm, Gd, Er and Lu) have been determined and refined using powder X-ray diffraction. The crystals are found to be orthorhombic, with the structure type changing consecutively in the order BaLaCuS3 → Eu2CuS3 → KZrCuS3 as the Ln3+ ionic radius decreases in the order La/Pr → Sm/Gd → Er/Lu. Variations of the structure parameters along the series of compounds studied are analyzed, and an effect caused by crystallochemical contraction on the stabilization of the respective structure types is demonstrated.
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- 2019
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39. Mapping pH at Cancer Cell Surfaces
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Donald M. Engelman, Yana K. Reshetnyak, Oleg A. Andreev, and Da Wei
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Cancer Research ,Tumor spheroid ,Cell ,Peptide ,Conjugated system ,Article ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Cell Line, Tumor ,Neoplasms ,Image Processing, Computer-Assisted ,medicine ,Humans ,Benzopyrans ,Radiology, Nuclear Medicine and imaging ,Neoplasm Metastasis ,chemistry.chemical_classification ,Chemistry ,Cell Membrane ,Spheroid ,Membrane Proteins ,Hydrogen-Ion Concentration ,Surface ph ,Membrane ,medicine.anatomical_structure ,Oncology ,Cancer cell ,Biophysics - Abstract
PURPOSE: To develop a tool to measure the pH at the surfaces of individual cells. PROCEDURES: The SNARF pH-sensitive dye was conjugated to a pHLIP® peptide (pH-Low Insertion Peptide) that binds cellular membranes in tumor spheroids. A beam splitter allows simultaneous recording of two images (580 and 640 nm) by a CCD camera. The ratio of the two images is converted into a pH map resolving single spheroid cells. An average pH for each cell is calculated and a pH histogram is derived. RESULTS: Surface pH depends on cellular glycolytic activity, which was varied by adding glucose or deoxy-glucose. Glucose was found to decrease the surface pH relative to the pH of the bulk solution. The surface pH of metastatic cancer cells was lower than that of non-metastatic cells indicating a higher glycolytic activity. CONCLUSIONS: Our method allows cell surface pH measurement and its correlation with cellular glycolytic activity.
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- 2019
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40. Targeting diseased tissues by pHLIP insertion at low cell surface pH
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Oleg A. Andreev, Donald M. Engelman, and Yana K. Reshetnyak
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Liposomes ,Nanotechnology ,imaging ,PET ,Drug delivery ,fluorescence ,Physiology ,QP1-981 - Abstract
The discovery of the pH Low Insertion Peptides (pHLIPs) provides an opportunity to develop imaging and drug delivery agents targeting extracellular acidity. Extracellular acidity is associated with many pathological states, such as those in cancer, ischemic stroke, neurotrauma, infection, lacerations and others. The metabolism of cells in injured or diseased tissues often results in the acidification of the extracellular environment, so acidosis might be useful as a general marker for the imaging and treatment of diseased states if an effective targeting method can be developed. The molecular mechanism of a pHLIP peptide is based on pH-dependent membrane-associated folding. pHLIPs, being moderately hydrophobic peptides, have high affinities for cellular membranes at normal pH, but fold and insert across membranes at low pH, allowing them to sense pH at the surfaces of cells in diseased tissues, where it is the lowest. Here we discuss the main principles of pHLIP interactions with membrane lipid bilayers at neutral and low pHs, the possibility of tuning the folding and insertion pH by peptide sequence variation, and potential applications of pHLIPs for imaging, therapy and image-guided interventions.
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- 2014
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41. QED calculation of two-electron one-photon transition probabilities in He-like ions
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Oleg Yu. Andreev, Deyang Yu, and K. N. Lyashchenko
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Physics ,Photon ,chemistry ,chemistry.chemical_element ,Electron ,Atomic physics ,Uranium ,Intensity ratio ,Ground state ,Boron ,Ion - Abstract
We consider theoretically the process of two-electron one-photon (TEOP) transitions to the ground state with the emission of a single ${K}_{\ensuremath{\alpha}\ensuremath{\alpha}}$ photon in a He-like sequence of atomic ions: from boron to uranium. The corresponding transition probabilities and transition energies are calculated within the QED theory. The calculations of the transition probabilities are performed in various gauges. The intensity ratios between the TEOP transitions and the other major transitions are presented.
- Published
- 2021
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42. Acidic environments trigger intracellular H+-sensing FAK proteins to re-balance sarcolemmal acid-base transporters and auto-regulate cardiomyocyte pH
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Abigail D Wilson, Mark A Richards, M Kate Curtis, Mala Gunadasa-Rohling, Stefania Monterisi, Aminah A Loonat, Jack J Miller, Vicky Ball, Andrew Lewis, Damian J Tyler, Anna Moshnikova, Oleg A Andreev, Yana K Reshetnyak, Carolyn Carr, and Pawel Swietach
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Physiology ,Acidity ,Sodium-Bicarbonate Symporters ,Myocardium ,Sodium ,Membrane Transport Proteins ,Cardiomyocyte ,Hydrogen-Ion Concentration ,Ischaemia ,Mice ,Bicarbonates ,Chlorides ,Physiology (medical) ,Homeostasis ,Animals ,pH sensor ,Myocytes, Cardiac ,Cardiology and Cardiovascular Medicine - Abstract
Aims In cardiomyocytes, acute disturbances to intracellular pH (pHi) are promptly corrected by a system of finely tuned sarcolemmal acid–base transporters. However, these fluxes become thermodynamically re-balanced in acidic environments, which inadvertently causes their set-point pHi to fall outside the physiological range. It is unclear whether an adaptive mechanism exists to correct this thermodynamic challenge, and return pHi to normal. Methods and results Following left ventricle cryo-damage, a diffuse pattern of low extracellular pH (pHe) was detected by acid-sensing pHLIP. Despite this, pHi measured in the beating heart (13C NMR) was normal. Myocytes had adapted to their acidic environment by reducing Cl−/HCO3− exchange (CBE)-dependent acid-loading and increasing Na+/H+ exchange (NHE1)-dependent acid-extrusion, as measured by fluorescence (cSNARF1). The outcome of this adaptation on pHi is revealed as a cytoplasmic alkalinization when cells are superfused at physiological pHe. Conversely, mice given oral bicarbonate (to improve systemic buffering) had reduced myocardial NHE1 expression, consistent with a needs-dependent expression of pHi-regulatory transporters. The response to sustained acidity could be replicated in vitro using neonatal ventricular myocytes incubated at low pHe for 48 h. The adaptive increase in NHE1 and decrease in CBE activities was linked to Slc9a1 (NHE1) up-regulation and Slc4a2 (AE2) down-regulation. This response was triggered by intracellular H+ ions because it persisted in the absence of CO2/HCO3− and became ablated when acidic incubation media had lower chloride, a solution manoeuvre that reduces the extent of pHi-decrease. Pharmacological inhibition of FAK-family non-receptor kinases, previously characterized as pH-sensors, ablated this pHi autoregulation. In support of a pHi-sensing role, FAK protein Pyk2 (auto)phosphorylation was reduced within minutes of exposure to acidity, ahead of adaptive changes to pHi control. Conclusions Cardiomyocytes fine-tune the expression of pHi-regulators so that pHi is at least 7.0. This autoregulatory feedback mechanism defines physiological pHi and protects it during pHe vulnerabilities.
- Published
- 2021
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43. Asymmetry in emission of photons with left- and right-hand circular polarizations in two-photon decay
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Victoria A. Knyazeva, Oleg Yu. Andreev, K. N. Lyashchenko, and Deyang Yu
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Left and right ,Physics ,Photon ,Two-photon excitation microscopy ,media_common.quotation_subject ,High Energy Physics::Experiment ,Atomic physics ,Polarization (waves) ,Measure (mathematics) ,Asymmetry ,Computer Science::Databases ,Ion ,media_common - Abstract
Two-photon decay of the $2s$ state in H-like ions is investigated. We report that asymmetry in the emission of photons with left- and right-hand circular polarizations can be observed in this transition if the initial state has a certain polarization. This asymmetry can be used to measure the polarization of ion beams.
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- 2021
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44. Tumor-selective, antigen-independent delivery of a pH sensitive peptide-topoisomerase inhibitor conjugate suppresses tumor growth without systemic toxicity
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Daniel Richard Marshall, Timothy Joseph Paradis, Ranjit S. Bindra, Vishwas M. Paralkar, Johanna Marie Csengery, Qing Zhang, Hannah M. Visca, Nalin Leelatian, Hunter Moore, Laurie Tylaska, Donald M. Engelman, Jane Bechtold, Jason M. Beckta, Sophia Gayle, Yana K. Reshetnyak, Peter M. Glazer, Patricia Bourassa, Oleg A. Andreev, Kelli Jones, Robert John Maguire, Lori Lopresti-Morrow, Robert J. Aiello, Jinny Van Doorn, and Ranjini K. Sundaram
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0301 basic medicine ,AcademicSubjects/SCI01140 ,AcademicSubjects/SCI01060 ,medicine.drug_class ,DNA repair ,Poly ADP ribose polymerase ,AcademicSubjects/SCI00030 ,Standard Article ,AcademicSubjects/SCI01180 ,03 medical and health sciences ,0302 clinical medicine ,Therapeutic index ,medicine ,Chemistry ,Cancer ,General Medicine ,medicine.disease ,Warburg effect ,030104 developmental biology ,030220 oncology & carcinogenesis ,PARP inhibitor ,Cancer research ,AcademicSubjects/SCI00980 ,Corrigendum ,Topoisomerase inhibitor ,Conjugate - Abstract
Topoisomerase inhibitors are potent DNA damaging agents which are widely used in oncology, and they demonstrate robust synergistic tumor cell killing in combination with DNA repair inhibitors, including poly(ADP)-ribose polymerase (PARP) inhibitors. However, their use has been severely limited by the inability to achieve a favorable therapeutic index due to severe systemic toxicities. Antibody-drug conjugates address this issue via antigen-dependent targeting and delivery of their payloads, but this approach requires specific antigens and yet still suffers from off-target toxicities. There is a high unmet need for a more universal tumor targeting technology to broaden the application of cytotoxic payloads. Acidification of the extracellular milieu arises from metabolic adaptions associated with the Warburg effect in cancer. Here we report the development of a pH-sensitive peptide-drug conjugate to deliver the topoisomerase inhibitor, exatecan, selectively to tumors in an antigen-independent manner. Using this approach, we demonstrate potent in vivo cytotoxicity, complete suppression of tumor growth across multiple human tumor models, and synergistic interactions with a PARP inhibitor. These data highlight the identification of a peptide-topoisomerase inhibitor conjugate for cancer therapy that provides a high therapeutic index, and is applicable to all types of human solid tumors in an antigen-independent manner., Graphical Abstract Graphical AbstractCBX-12 is a pH-sensitive peptide-drug conjugate that selectively delivers the TOP1 inhibitor exatecan into tumor cells in an antigen agnostic manner. The peptide forms an alpha helix only in the low pH tumor microenvironment, allowing directional insertion of the peptide across the tumor membrane, cleavage of the linker within the cytosol, and release of free exatecan within the tumor cell. This pH-based delivery approach results in a high therapeutic index universally across solid tumors.
- Published
- 2021
45. Application of the Electric Drive of the Power Unit of the Small Traction Tractor
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Oleg P. Andreev, Alexandr G. Levshin, Nikolay E. Kabdin, Valery L. Chumakov, and Anton V. Bizhaev
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Tractor ,business.product_category ,Computer science ,medicine.medical_treatment ,Power unit ,Traction (orthopedics) ,Electric traction ,Automotive engineering ,Electric power transmission ,Work (electrical) ,medicine ,Electric cars ,business ,Electric drive - Abstract
Nowadays, one of the tasks in the agricultural industry is the use of tractors in indoor facilities. Greenhouses and indoor farm premises impose increased toxicity requirements for tractor ICE. This paper considers a solution to this problem by using electric traction on small traction tractors. When developing such machines, an essential element is the justification of its parameters, which are usually laid based on the tasks of a tractor. An essential part of the issue is the choice of the layout of a power unit and the type of energy used by it. Based on the work tasks, we analyzed the application of electric drive with consideration of the traction features of the tractor. The paper provides a comparative assessment and general provisions on this issue.
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- 2021
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46. Assessing Design Decisions in Agriculture
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Lidiya M. Trushina, Oleg P. Andreev, Oksana G. Karataeva, Mihail V. Stepanov, and Olga V. Chekha
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ComputingMilieux_GENERAL ,Engineering management ,Agriculture ,business.industry ,Economic evaluation ,Relevance (information retrieval) ,Business ,Agricultural productivity ,Training (civil) - Abstract
The relevance of the research is due to the situation in training agricultural engineers with the appropriate professional competencies. According to statistics, the industry currently lacks highly qualified specialists in agricultural engineering. The study of the theoretical and practical aspects of the technical and economic evaluation of design decisions in agricultural engineering is the main direction of training competitive personnel and ensuring the innovative development of agricultural production in Russia.
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- 2021
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47. Targeted suppression of microRNA-33 in lesional macrophages using pH low-insertion peptides (pHLIP) improves atherosclerotic plaque regression
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Jakub Toczek, Nathan D. Price, Xinbo Zhang, Elisa Araldi, Noemi Rotllan, Oleg A. Andreev, Carlos Fernández-Hernando, Wen Zhong, Yana K. Reshetnyak, Yajaira Suárez, Anna Moshnikova, Raman Bahal, Mehran M. Sadeghi, Alberto Canfrán-Duque, and Shipra Malik
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business.industry ,microRNA ,Plaque regression ,Cancer research ,Medicine ,business - Abstract
Hypoxia and tissue acidification occur in the macrophage-rich regions of advanced atherosclerotic lesions due to the higher oxygen demand of activated immune cells and insufficient oxygen supply. Our group and others originally identified microRNA-33 (miR-33) as critical regulator of cellular lipid homeostasis and lipoprotein metabolism controlling the development of atherosclerosis. Our prior work has demonstrated that pH Low-Insertion Peptides (pHLIP) can be used to direct miR-33 inhibitors to acidic microenvironments and protect against kidney fibrosis. Here we utilize anti-miR-33 conjugated pHLIP constructs to target macrophages located in atherosclerosis plaques. The inhibition of miR-33 using pHLIP-directed targeting increased collagen content and decreased lesional lipid accumulation within atherosclerotic plaques in a murine model of atherosclerosis regression. Single cell RNA sequencing analysis revealed higher expression of fibrotic genes (Col2a1, Col3a1, Fn1, Dcn, etc) and tissue inhibitor of metalloproteinase 3 (Timp3), and downregulation of matrix metallopeptidase 12 (Mmp12) in macrophages from atherosclerotic lesions targeted by pHLIP- anti-miR-33. These results suggest a potential application of pHLIP for treating advanced atherosclerosis via pharmacological inhibition of miR-33.
- Published
- 2020
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48. Kinetics of pHLIP peptide insertion into and exit from a membrane
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Donald M. Engelman, Yana K. Reshetnyak, Dhammika Weerakkody, Gregory Slaybaugh, and Oleg A. Andreev
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0301 basic medicine ,Protein Folding ,Kinetics ,Lipid Bilayers ,Peptide ,03 medical and health sciences ,0302 clinical medicine ,Humans ,Lipid bilayer ,chemistry.chemical_classification ,Multidisciplinary ,Bilayer ,Cell Membrane ,Tryptophan ,Membrane Proteins ,Biological Sciences ,Hydrogen-Ion Concentration ,Peptide Fragments ,N-terminus ,Transmembrane domain ,030104 developmental biology ,Membrane ,chemistry ,030220 oncology & carcinogenesis ,Liposomes ,Mutation ,Biophysics ,Thermodynamics - Abstract
To advance mechanistic understanding of membrane-associated peptide folding and insertion, we have studied the kinetics of three single tryptophan pHLIP (pH-Low Insertion Peptide) variants, where tryptophan residues are located near the N terminus, near the middle, and near the inserting C-terminal end of the pHLIP transmembrane helix. Single-tryptophan pHLIP variants allowed us to probe different parts of the peptide in the pathways of peptide insertion into the lipid bilayer (triggered by a pH drop) and peptide exit from the bilayer (triggered by a rise in pH). By using pH jumps of different magnitudes, we slowed down the processes and established the intermediates that helped us to understand the principles of insertion and exit. The obtained results should also aid the applications in medicine that are now entering the clinic.
- Published
- 2020
49. MODELING OF DIESEL ENGINE OPERATION PROCESS AS AN OBJECT OF SPEED CONTROL
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Oleg P. Andreev and Oleg N. Sleptsov
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Electronic speed control ,Computer science ,Process (computing) ,Diesel engine ,Object (computer science) ,Automotive engineering - Published
- 2019
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50. Europium Oxysulfate Eu2O2SO4 Crystal Structure
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Yu. G. Denisenko, Svetlana S. Volkova, Oleg V. Andreev, Nikolay A. Khritokhin, and Nikita O. Azarapin
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Materials science ,Materials Science (miscellaneous) ,Infrared spectroscopy ,chemistry.chemical_element ,Crystal structure ,010402 general chemistry ,010403 inorganic & nuclear chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,chemistry ,Group (periodic table) ,Tetrahedron ,Physical and Theoretical Chemistry ,Sulfate ,Europium ,Powder diffraction ,Monoclinic crystal system - Abstract
The europium oxysulfate crystal structure was solved by X-ray powder diffraction. The compound crystallizes in monoclinic crystal system. The unit cell parameters are a = 13.6952(1) A, b = 4.1929(4) A, c = 8.1393(2) A, β = 107.455(4)°, space group C2/c. The three major structural elements are recognized to be Eu atoms, SO4 tetrahedra, and μ-O atoms, and their coordination environments were analyzed. The specific structural elements are infinite screw chains composed of trigonal prisms [EuO9]; sulfate tetrahedra [(SO4)Eu8] enclosed into cubes built of europium atoms; and infinite chains composed of tetrahedra [OEu4]. Rationale was given to the splitting of the IR absorption bands corresponding to the vibrations of sulfate groups.
- Published
- 2019
- Full Text
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