Ultrathin Langmuir–Schaefer films of slipped-cofacial J-type phthalocyanine dimer: Supramolecular organization, UV/Vis/NIR study and nonlinear absorbance of femtosecond laser radiation
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15.04.2021 |
Kazak A.V.
Marchenkova M.A.
Khorkov K.S.
Kochuev D.A.
Rogachev A.V.
Kholodkov I.V.
Usol'tseva N.V.
Savelyev M.S.
Tolbin A.Y.
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Applied Surface Science |
10.1016/j.apsusc.2021.148993 |
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© 2021 Elsevier B.V. Based on a comprehensive theoretical and experimental approach, a low-defect thin film of stable dimeric phthalocyanine zinc complex (bis-[2-hydroxy-9(10),16(17), 23(24)-tri-tert-butylphthalocyanine]zinc – J-[OHPctZn]2) was prepared. It is shown that the dye forms stable amorphous edge-on monolayers at the air/water interface with an insignificant content of cylindrical 3D aggregates. These floating layers keep their structure when transferred by the Langmuir-Schaefer method onto a solid substrate, demonstrating a tendency towards ordered H-aggregation with preserving their linear molecular properties. Mixed two- and three-photon absorption of femtosecond laser pulses (280 fs) was firstly detected on this sample, as well as the ability of a material to the nonlinear attenuation of the intense irradiation, which is important for optical limiting.
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Lost or Forgotten: The nuclear cathepsin protein isoforms in cancer
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10.10.2019 |
Soond S.
Kozhevnikova M.
Frolova A.
Savvateeva L.
Plotnikov E.
Townsend P.
Han Y.
Zamyatnin A.
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Cancer Letters |
10.1016/j.canlet.2019.07.020 |
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© 2019 Elsevier B.V. While research into the role of cathepsins has been progressing at an exponential pace over the years, research into their respective isoform proteins has been less frenetic. In view of the functional and biological potential of such protein isoforms in model systems for cancer during their initial discovery, much later they have offered a new direction in the field of cathepsin basic and applied research. Consequently, the analysis of such isoforms has laid strong foundations in revealing other important regulatory aspects of the cathepsin proteins in general. In this review article, we address these key aspects of cathepsin isoform proteins, with particular emphasis on how they have shaped what is now known in the context of nuclear cathepsin localization and what potential these hold as nuclear-based therapeutic targets in cancer.
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Safety of laser and terahertz femtosecond pulses effect on living bioobjects
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13.08.2018 |
Sitnikov D.
Ilina I.
Pronkin A.
Zurina I.
Gorkun A.
Khramova Y.
Kosheleva N.
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Proceedings - International Conference Laser Optics 2018, ICLO 2018 |
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© 2018 IEEE. Modern laser technologies have a wide range of scientific, commercial, medical and other applications. In medicine, lasers are used both for diagnostic, therapeutic, and surgical purposes. Safety of laser radiation in assisted reproductive technologies is discussed in the paper. Efficiency of using femtosecond (fs) laser pulses to perform noncontact embryo biopsy as well as laser-assisted hatching is shown. First results on femtosecond laser marking on the surface of embryo outer shell for individual embryo tagging are also presented. Question of safety of THz radiation for living objects (starting at the cellular level and ending with the organism in whole) is still a matter of controversy and requires further study. Experimental study of high-power THz pulses effect on living 2D cell culture is presented. MSC cells are exposed to multiple (from 80 to 100) THz pulses with intensities up to 1 MV/cm. No short-term damage effects are observed during first hours post cell irradiation.
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Fabrication of superconducting nanowire single-photon detectors by nonlinear femtosecond optical lithography
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01.02.2018 |
Minaev N.
Tarkhov M.
Dudova D.
Timashev P.
Chichkov B.
Bagratashvili V.
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Laser Physics Letters |
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2 |
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© 2018 Astro Ltd. This paper describes a new approach to the fabrication of superconducting nanowire single-photon detectors from ultrathin NbN films on SiO2 substrates. The technology is based on nonlinear femtosecond optical lithography and includes direct formation of the sensitive element of the detector (the meander) through femtosecond laser exposure of the polymethyl methacrylate resist at a wavelength of 525 nm and subsequent removal of NbN using plasma-chemical etching. The nonlinear femtosecond optical lithography method allows the formation of planar structures with a spatial resolution of ∼50 nm. These structures were used to fabricate single-photon superconducting detectors with quantum efficiency no worse than 8% at a wavelength of 1310 nm and dark count rate of 10 s-1 at liquid helium temperature.
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Highly effective 525 nm femtosecond laser crosslinking of collagen and strengthening of a human donor cornea
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01.01.2018 |
Shavkuta B.
Gerasimov M.
Minaev N.
Kuznetsova D.
Dudenkova V.
Mushkova I.
Malyugin B.
Kotova S.
Timashev P.
Kostenev S.
Chichkov B.
Bagratashvili V.
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Laser Physics Letters |
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4 |
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© 2017 Astro Ltd. A two-photon laser femtosecond crosslinking process at the wavelength of 525 nm was studied in a human donor cornea in the presence of riboflavin using two-photon optical microscopy and nanoindentation. It was shown that such an approach results in efficient crosslinking of the corneal collagen and a significant (three-fold) increase in the Young's modulus of the corneal structure. Application of a femtosecond laser with the wavelength of 525 nm allows a drastic enhancement of efficiency in the presence of riboflavin on human corneas and a 50-fold reduction of the laser treatment duration in comparison with the use of a femtosecond laser with the wavelength of 760 nm. We relate this effect to a significant growth in the coefficient of two-photon absorption due to the laser wavelength falling within the edge of the photoinitiator (riboflavin) absorption band. Our studies on a donor human cornea demonstrate the good potential for the clinical application of a femtosecond laser with the wavelength of 525 nm for increasing the cornea rigidity using the two-photon laser femtosecond crosslinking technique.
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