Tellurium Nanostructures Obtained by Thermal Evaporation Method

Crystallography Reports - Tellurium (Te) nanostructures have been obtained on glassy carbon substrates by thermal evaporation in an argon atmosphere. The sizes and shape of Te particles have been...     

Current Status and Objectives of Modernizing the Engineering,Physical, and Energy Infrastructure of the SFT Facility for the Implementation of the Ignitor Project

Physics of Atomic Nuclei - The Ignitor tokamak nuclear fusion research project is one of the most ambitious initiatives undertaken under the long-term scientific cooperation program between the...     

Magnetoplastic Effect in Te-Doped GaAs Single Crystals

Crystallography Reports - The influence of a dc magnetic field on the motion of growth dislocations with a density of (0.7–7.0) × 104 cm–2 and the electron density in the range of...     

A Study of the Protective Properties of a Combined Cermet Material upon a High-Speed Impact

Technical Physics - The ballistic resistance of a combined cermet material based on a high-hardness ceramic bound with an intermetallide on a high-strength metal substrate, (TiB2 + NiTi) + Ti, is...     

Exploring the Interplay between Drug Release and Targeting of Lipid-Like Polymer Nanoparticles Loaded with Doxorubicin

Targeted delivery of doxorubicin still poses a challenge with regards to the quantities reaching the target site as well as the specificity of the uptake. In the present approach, two colloidal nanocarrier systems, NanoCore-6.4 and NanoCore-7.4, loaded with doxorubicin and characterized by different drug release behaviors were evaluated in vitro and in vivo. The nanoparticles utilize a specific surface design to modulate the lipid corona by attracting blood-borne apolipoproteins involved in the endogenous transport of chylomicrons across the blood–brain barrier. When applying this strategy, the fine balance between drug release and carrier accumulation is responsible for targeted delivery. Drug release experiments in an aqueous medium resulted in a difference in drug release of approximately 20%, while a 10% difference was found in human serum. This difference affected the partitioning of doxorubicin in human blood and was reflected by the outcome of the pharmacokinetic study in rats. For the fast-releasing formulation NanoCore-6.4, the AUC_0→1h was significantly lower (2999.1 ng × h/mL) than the one of NanoCore-7.4 (3589.5 ng × h/mL). A compartmental analysis using the physiologically-based nanocarrier biopharmaceutics model indicated a significant difference in the release behavior and targeting capability. A fraction of approximately 7.310–7.615% of NanoCore-7.4 was available for drug targeting, while for NanoCore-6.4 only 5.740–6.057% of the injected doxorubicin was accumulated. Although the targeting capabilities indicate bioequivalent behavior, they provide evidence for the quality-by-design approach followed in formulation development.     

Quantum chemical studies of azoles

The results of theoretical search for model transition states of the electrophilic substitution reaction in 2H-tetrazole (1) without the preliminary formation of N-protonated azolium salts are presented for two routes that were previously suggested by the authors and thermodynamically investigated: A, the attack of molecule 1 by the nucleophile (HO^–(aq)) to form the anion to which the electrophile H₃O⁺(aq)) is added and B, the attack of molecule 1 by the same electrophile followed by the addition of the same nucleophile to the specifically solvated protonated species formed in the preceding reaction step. The calculations were performed using the DFT/B3LYP/6-31G(d) method and the scanning procedure of the potential energy surface (PES). Both steps of route A turned out to be nearly barrierless, while in route B only its first step is barrierless and the second one is conjugated with passing an activation barrier of ～45 kcal mol^–1 between non-interacting or weakly interacting reactants and electrophilic substitution products. Unlike the specifically solvated protonated species of 1H-tetrazole in an aqueous solution, a similar species of 2H-tetrazole does not form a prereaction complex with the attacking nucleophile (HO^–(aq)) and the five-membered ring is destroyed in fact in the nitrogen-containing reaction product formed after passing the activation barrier. The optimized structure of the transition state differs strongly from the nitrogen-containing structure of the reaction product with the destroyed ring, which was found by scanning of the PES.     

Channel effect in isomeric ratio of 137m,gCe produced in different nuclear reactions

This work presents the experimental study of the isomeric ratio of ^137mCe–^137gCe produced in ¹³⁸Ce(γ, n) ^137m,gCe photonuclear reaction, in neutron capture reaction ¹³⁶Ce(n, γ) ^137m,gCe and in the two simultaneous reactions ¹³⁸Ce(γ, n) ^137m,gCe and ¹³⁶Ce(n, γ) ^137m,gCe in the mixed photon—neutron field by the activation method. The investigated samples were irradiated at the bremsstrahlung photon flux, in the epithermal and thermal-epithermal neutron beam and in the mixed photon-neutron field constructed at the electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The results were analyzed, discussed and compared with those of other authors to examine the role of the channel effect in nuclear reaction and provide the nuclear data for theoretical model interpretation of nuclear reactions.

     

Synthesis of Decaborane by the Reaction of Sodium Undecaborate with Mild Organic Oxidants

New organic oxidants (aldehydes and ketones) allowing efficient synthesis of decaborane in a high yield via intermediate alkali metal salt were found. The sodium undecaborate oxidation process was refined, and new reaction stoichiometry was suggested.     

Flow of a vortical stream in the neighborhood of the critical point

A study was made of the axisymmetric flow of a viscous incompressible fluid in the neighborhood of the critical point of an obstacle when steady-state vortices oriented in the direction of the angular coordinate are introduced into the oncoming flow. A solution is presented of the equation for the transfer of a vortex in the case of an external flow containing a single largesize vortex in the low-frequency part of the spectrum. Using a finite integral Hankel transform, the problem is reduced to the solution of a system of ordinary differential equations. It is shown that a sufficiently large-size vortex can have a considerable effect on the structure of viscous flow near an obstacle.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 85–89, November–December, 1970.     

New heterogeneous catalytic systems based on highly porous ceramic materials modified with immobilized d-metal cage complexes for H2 production from CH4

1. Download : Download high-res image (119KB)
2. Download : Download full-size image