The photosensitizing ability of a boron difluoride beta-diketonate derivative has been studied. The spectral and luminescent properties of the dye and the spectral-kinetic characteristics of its triplet state have been established. The quantum efficiency of singlet oxygen formation has been determined. The in vitro photosensitizing activity of the dye against tumor cells of colon adenocarcinoma was demonstrated, and the values of dark and photoinduced cytotoxicity were obtained.

Исследована фотосенсибилизирующая способность производного бета-дикетоната дифторида бора. Установлены спектрально-люминесцентные свойства красителя и спектрально-кинетические характеристики его триплетного состояния. Определена квантовая эффективность образования синглетного кислорода. Показана фотосенсибилизирующая активность красителя в отношении опухолевых клеток аденокарциномы толстой кишки in vitro и получены значения темновой и фотоиндуцированной цитотоксичности.

An analysis of the results of time-resolved transient S1→Sn absorption spectroscopy studies and quantum chemical calculations of the dye (2E,5E)-2,5-bis[4-(1,4,7,10,13-pentaoxa-16-azacyclooctadecane-16-yl)benzylidene]cyclopentanone (1) and its metal complexes confirm the generality of the phenomenon of photoinduced recoordination of metal cations in the complexes of bis(aza-18-crown-6)-containing derivatives of the dibenzylidenecyclobutanone (dibenzylidenecyclopentanone) series. The results obtained confirmed the existence of the first stage of photoinduced recoordination of metal cations in the 1 • (Mn+)2 (M = Ba2+, Ca2+, K+) complexes which completes within a few hundreds of femtoseconds. The process involves cleavage of the N—M bond followed by displacement of the metal cation from its equilibrium position in the azacrown ether cavity and by transformation of the “axial” conformation of the complex to “equatorial” one. It was demonstrated that the barrier photoinduced recoordination of the cation in the 1 • (Ba2+)2 complex is accompanied by the change of the type of the solvation shell of the crowned Ba2+ cation in the following order: (2+1)MeCN, (3+1)MeCN, 4MeCN. In a low-temperature butyronitrile glassy matrix at 77 K, the photoinduced recoordination is completely suppressed. The Mg2+, Li+, and Na+ cations can form not only the inclusion complexes, but also the 1: 3 complexes ((Mn+) • 1 • (Mn+)2) of moderate stability through additional coordination to the carbonyl group of the dye. The radii, rS, of solvates of different-stoichiometry complexes containing the same metal cation determined from the data of anisotropy decay kinetics of S1→Sn absorption are about 9.2 Å for 1 • (Mg2+)2 and nearly 11.5 Å for Mg2+ • 1 • (Mg2+)2.

The future space-based GAMMA-400 scientific observatory is being developed under the Federal Space Program of Russian Federation in the period from 2016-2025. This observatory includes a γ-ray telescope, which will detect gamma rays in the energy range from ~20 MeV to several TeV with high angular and energy resolutions and cosmic-ray electrons + positrons up to several tens of TeV using main and lateral appertures. Recent experimental observations indicate a possible existence of a break in the electrons + positrons spectrum at around TeV energies. A number of speculations to explain this phenomenon have arisen. This article presents the method of high-energy electrons detection from the lateral aperture of the GAMMA-400 gamma-ray telescope. This method implements the machine learning analysis and provides the high-energy proton background rejection at the level of 10$^4$ in the energy range from 100 GeV to 10 TeV. The effective acceptance for electron detection with such proton rejection is about 0.52 m$^2$×sr for the four lateral sides of the GAMMA-400 gamma-ray telescope. This effective acceptance exceeds by several times that of CALET and DAMPE experiments. This capability of our instrument will allow to improve significantly the measurements of electron + positron flux above 1 TeV and, hence, understand better the debatable spectrum break.

The GAMMA-400 gamma-ray telescope is the successor of Soviet and Russian gamma-ray telescopes. GAMMA-400 is being developed for cosmophysical research in accordance with the Russian Federal Space Program 2016–2025. The GAMMA-400 experiment will be implemented aboard the Russian astrophysical space observatory in a highly elliptic orbit during 7 years to provide new data on gamma-ray emission mainly from the Galactic plane, Galactic Center, the Sun and cosmic-ray electron + positron fluxes. The main mode of observations will be the continuous point-source mode with the duration of up to ∼ 100 days. The GAMMA-400 gamma-ray telescope will study high-energy gamma-ray emission up to several TeV and cosmic-ray electrons + positrons up to 20 TeV. GAMMA-400 will have the never-achieved angular resolution, the high-energy and time resolutions, as well as very good separation efficiency of gamma rays from cosmic-ray background and of electrons + positrons from protons. The distinctive features of GAMMA-400 are the excellent angular resolution of ∼0.01^∘ at E_γ=100 GeV that exceeds resolutions of the space-based and ground-based gamma-ray telescopes by a factor of 5–10, as well as high-energy resolution of ∼2% at E_γ=100 GeV. GAMMA-400 studies can discover gamma-ray emission from annihilation or decay of dark matter particles, identify many unassociated discrete sources, explore the structure of extended sources, search for gamma-ray bursts and solar gamma-ray flares, improve the data on cosmic-ray electron + positron spectra for energies of >50 GeV.

The present work analyzes various aspects of M31 gamma-ray halo emission in its relation to annihilating dark matter (DM). The main aspect is the predicted effect of asymmetry of the intensity of emission due to inverse Compton scattering (ICS) of a possible population of relativistic electrons and positrons ($e^\pm$) in the galactic halo on starlight photons. This asymmetry is expected to exist around the major galactic axis, and arises due to anisotropy of the interstellar radiation field and the inclination of M31. ICS emission and its asymmetry were modeled by GALPROP code for the trial case of $e^\pm$ generated by annihilating weakly interacting massive particles (WIMPs) with various properties. The asymmetry was obtained to appear at photon energies above $\sim$ 0.1 MeV. Morphological and spectral properties of the asymmetry were studied in detail. Potential observational detection of the asymmetry may allow to infer the leptonic fraction in the emission generation mechanism, thus providing valuable inferences for understanding the nature of M31 gamma-ray halo emission. Specific asymmetry predictions were made for the recently claimed DM interpretation of the outer halo emission. The paper also studied the role of secondary -- ICS and bremsstrahlung -- emissions due to DM annihilation for that interpretation. And, finally, the latter was shown to be somewhat restricted by the recently derived WIMP constraints from radio data on M31.

The upcoming GAMMA-400 experiment will be implemented aboard the Russian astrophysical space observatory, which will be operating in a highly elliptical orbit over a period of 7 years to provide new data on gamma-ray emissions and cosmic-ray electron + positron fluxes, mainly from the galactic plane, the Galactic Center, and the Sun. The main observation mode will be a continuous point-source mode, with a duration of up to ~100 days. The GAMMA-400 gamma-ray telescope will study high-energy gamma-ray emissions of up to several TeV and cosmic-ray electrons + positrons up to 20 TeV. The GAMMA-400 telescope will have a high angular resolution, high energy and time resolutions, and a very good separation efficiency for separating gamma rays from the cosmic-ray background and the electrons + positrons from protons. A distinctive feature of the GAMMA-400 gamma-ray telescope is its wonderful angular resolution for energies of >30 GeV (0.01° for Eγ = 100 GeV), which exceeds the resolutions of space-based and ground-based gamma-ray telescopes by a factor of 5–10. GAMMA-400 studies can reveal gamma-ray emissions from dark matter particles’ annihilation or decay, identify many unassociated, discrete sources, explore the extended sources’ structures, and improve the cosmic-ray electron + positron spectra data for energies of >30 GeV.

Polycrystalline samples of the mixed cyclotriphosphates KMgP3O9, KCaP3O9, RbMgP3O9, RbCaP3O9, CsCaP3O9, and CsSrP3O9 containing Bi+ bismuth impurity monocations have been prepared via crystallization from a melt of appropriate composition. The presence of Bi+ is responsible for broadband bright near-IR luminescence in all of the materials. The shape of the photoluminescence and photoluminescence excitation spectra has been shown to be determined by the nature of the alkaline earth cation in the composition in the cyclotriphosphates and the symmetry of the local environment of the Bi+ ions under the assumption that they isomorphously substitute for alkali metal cations in the crystal lattice of the cyclotriphosphates. The characteristic photoluminescence decay time is also determined by the symmetry of the local environment of Bi+.

Краткое сообщение, аннотации и ключевых нет

The present work derived the robust constraints on annihilating weakly interacting massive particle (WIMP) parameters utilizing new radio observations of M31 as well as new studies of its dark matter distribution and other properties. The characteristics of emission due to dark matter (DM) annihilation were computed in the frame of a 2D galactic model employing GALPROP code adapted specifically for M31. This enabled us to refine various inaccuracies of previous studies on the subject. DM constraints were obtained for two representative annihilation channels: chi chi -> b (b) over bar and chi chi -> tau(+)tau(-). A wide variety of radio data was utilized in the frequency range approximate to(0.1-10)GHz. As the result, the thermal WIMP lighter than fiducially approximate to 70 GeV for b (b) over bar channel and approximate to 40 GeV for tau(+)tau(-) was excluded. The corresponding mass threshold uncertainty ranges were estimated to be 20-210 GeV and 18-89 GeV. The obtained exclusions are competitive to those from Fermi-LAT observations of dwarfs and AMS-02 measurements of antiprotons. Our constraints do not exclude the explanation of the gamma-ray outer halo of M31 and the Galactic Center excess by annihilating DM. The thermal WIMP with m(x) approximate to 70 GeV, which explains the outer halo, would make a significant contribution to the nonthermal radio flux in M31 nucleus, fitting well both the spectrum and morphology. And, finally, we questioned the possibility claimed in other studies to robustly constrain heavy thermal WIMP with m(x) > 100 GeV by radio data on M31.

The currently developing space-based gamma-ray telescope GAMMA-400 will measure the gamma-ray and electron + positron fluxes using the main top-down aperture in the energy range from ~20 MeV to several TeV in a highly elliptic orbit (without shading the telescope by the Earth and outside the radiation belts) continuously for a long time. The instrument will provide fundamentally new data on discrete gamma-ray sources, gamma-ray bursts (GRBs), sources and propagation of Galactic cosmic rays and signatures of dark matter due to its unique angular and energy resolutions in the wide energy range. The gamma-ray telescope consists of the anticoincidence system (AC), the converter-tracker (C), the time-of-flight system (S1 and S2), the position-sensitive and electromagnetic calorimeters (CC1 and CC2), scintillation detectors (S3 and S4) located above and behind the CC2 calorimeter and lateral detectors (LD) located around the CC2 calorimeter. In this paper, the capabilities of the GAMMA-400 gamma-ray telescope to measure fluxes of GRBs from lateral directions of CC2 are analyzed using Monte-Carlo simulations. The analysis is based on off-line second-level trigger construction using signals from S3, CC2, S4 and LD detectors. For checking the numerical algorithm the data from space-based GBM and LAT instruments of the Fermi experiment are used, namely, three long bursts: GRB 080916C, GRB 090902B, GRB 090926A and one short burst GRB 090510A. The obtained results allow us to conclude that from lateral directions the GAMMA-400 space-based gamma-ray telescope will reliably measure the spectra of bright GRBs in the energy range from ~10 to ~100 MeV with the on-axis effective area of about 0.13 m2 for each of the four sides of CC2 and total field of view of about 6 sr.

The future space-based GAMMA-400 gamma-ray telescope will operate onboard the Russian astrophysical observatory in a highly elliptic orbit during 7 years to observe Galactic plane, Galactic Center, Fermi Bubbles, Crab, Vela, Cygnus X, Geminga, Sun, and other regions and measure gamma- and cosmic-ray fluxes. Observations will be performed in the point-source mode continuously for a long time (~100 days). GAMMA-400 will measure gamma rays in the energy range from ~20 MeV to several TeV and cosmic-ray electrons + positrons up to several tens TeV. GAMMA-400 instrument will have very good angle and energy resolutions, high separation efficiency of gamma rays from cosmic-ray background, as well as electrons + positrons from protons. The main feature of GAMMA-400 is the unprecedented angular resolution for energies >30 GeV better than the space-based and ground-based gamma-ray telescopes by a factor of 5-10. GAMMA-400 observations will permit to resolve gamma rays from annihilation or decay of dark matter particles, identify many discrete sources, clarify the structure of extended sources, specify the data on cosmic-ray electron + positron spectra.

The spectral-kinetic characteristics of the singlet and triplet excited states of octaphenyl-substituted erbium phthalocyanine are established. It is shown that the compound has high values of the quantum yields of fluorescence (0.50) and singlet oxygen (0.43). The lifetimes of the excited singlet (4.9 ns) and triplet states (1.4 ms) are determined. The binding constant of phthalocyanine to bovine serum albumin (5.5 × 106 M–1) is calculated, indicating the effective binding of the test substance to albumin. The predominant accumulation of the dye in the cell cytoplasm on the model colon adenocarcinoma cell line (HCT116 cell line) is established. The localization of phthalocyanine in mitochondria and structures of the endoplasmic reticulum is established by confocal microscopy.

The future space-based GAMMA-400 $$\gamma$$ -ray telescope will operate onboard the Russian astrophysical observatory in a highly elliptic orbit during 7 years. Observing $$\gamma$$ -ray sources from Galactic plane, $$\gamma$$ -ray bursts, $$\gamma$$ -ray diffuse emission, $$\gamma$$ rays from the Sun, and $$\gamma$$ rays from dark matter particles will be performed uninterruptedly for a long time ( $${\sim}$$ 100 days) in point-source mode in contrast to scanning mode for Fermi-LAT and other space- and ground-based instruments. GAMMA-400 will measure $$\gamma$$ rays in the energy range from $${\sim}$$ 20 MeV to several TeV units, have the unprecedented angular ( $${\sim}0.01^{\circ}$$ at $$E_{\gamma}=100$$ GeV) and energy ( $${\sim}2{\%}$$ at $$E_{\gamma}=100$$ GeV) resolutions better than for Fermi-LAT, as well as ground-based $$\gamma$$ -ray facilities, by a factor of 5–10, and perfectly separate $$\gamma$$ rays from cosmic-ray background.

In order to increase the bioavailability of water-insoluble pyropheophorbide-a (PPP-a) methyl ester, its liposomal form is prepared and the physicochemical and photochemical properties of this form are studied. The quantum yield of 1O2 is found to have a bell-shaped dependence on the concentration of PPP-a in the lipid phase of liposomes with the maximum at 31.6 µmol/g of lipids. The IR spectroscopy shows the photoinduced formation of aldehyde groups in the lipid phase of liposomes. The intracellular accumulation of PPP-a is confirmed by confocal microscopy.

Recent observations of gamma rays with the Fermi Large Area Telescope (LAT) in the direction of the inner galaxy revealed a mysterious excess of GeV. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs) generation and propagation with a peak in the spectrum around a few GeV. Popular interpretations of this excess are that it is due to either spherically distributed annihilating dark matter (DM) or an abnormal population of millisecond pulsars. We suggest an alternative explanation of the excess through the CR interactions with molecular clouds in the Galactic Center (GC) region. We assumed that the excess could be imitated by the emission of molecular clouds with depleted density of CRs with energies below ∼10 GeV inside. A novelty of our work is in detailed elaboration of the depletion mechanism of CRs with the mentioned energies through the “barrier” near the cloud edge formed by the self-excited MHD turbulence. This depletion of CRs inside the clouds may be a reason for the deficit of gamma rays from the Central Molecular Zone (CMZ) at energies below a few GeV. This in turn changes the ratio between various emission components at those energies and may potentially absorb the GeV excess by a simple renormalization of key components.

Porphyrins and related compounds are widely used as nanomaterials [1], in organic solar batteries [2], for medical treatment of various skin deceases [3], as well as photosensitizers for photodynamic therapy (PDT) [4, 5]. A series of compounds already have been approved for clinical practice [6]. Chemical modification of the initial molecules is one of the methods for enhancing the efficacy of molecules (photosensitizers) used in PDT. This modification is directed to improvement of the photodynamic properties of the molecules, to an increase in their bioavailability and a decrease in their system (dark) toxicity. In this work, we studied tetraphenylporphyrin with a carboranylsuccinimide substituent in the β-position of the porphyrin macrocycle. Earlier, it was shown that carborane derivatives of porphyrins exhibited higher antitumor activity than their nonborylated analogs [7]. The interaction of photosensitizers with stable radicals is of interest because of intensification of intersystem crossing by a paramagnetic particle (nitroxyl radical). The conjugate of naphthalenediimide derivative with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) was studied in [8]. As a result of the covalent bonding of the chromophore with the stable radical, the properties of this compound exhibits an effect similar to the heavy atom effect. It is of interest to explore the interaction of tetrapyrrole molecules and stable radicals for possible design of novel promising photosensitizers. In this study we investigated the interaction of the triplet state of 2-{3-[(o-carboran-1'-yl)thio]pyrrolidine-2,5-dion-1-yl}-5,10,15,20-tetraphenylporphyrin (P), synthesized according to the procedure described in [9], with the stable nitroxyl radical (2R) 4hydroxy-2,2,6,6tetramethylpiperidin-1-yl)oxyl (TEMPOL) (Sigma-Aldrich) by pulse photolysis technique. Absorption spectra were recorded on a Shimadzu UV-3101PC spectrophotometer in quartz cells (1 × 1 cm). The decay of the triplet states and the triplet–triplet absorption spectra of P were obtained on a pulse photolysis setup with the use of a quartz cell with an optical pathlength of 20 cm and a Xe lamp with a flash energy of 80 J (15 μs) [10] in ethanol and toluene solutions. Before photoexcitation, oxygen was removed by evacuation under reduced pressure. PhoN NH N