Temperature dependence of the rate constant of hydrogen isotope interactions with a lithium capillary-porous system under reactor irradiation

Experiments with a sample of a lithium capillary-porous system (CPS) were performed at the reactor IVG-1.M of the Institute of Atomic Energy NNC RK to study the effects of neutron irradiation on the parameters of hydrogen isotope interactions with a lithium CPS. The absorption technique was used during the experiments, and this technique allowed the temperature dependences of the hydrogen isotope interaction rate constants with the lithium CPS to be obtained under various reactor powers. The obtained dependencies were used to determine the main interaction parameters: the activation energies and the pre-exponents of the Arrhenius dependence of the hydrogen interaction rate constants with lithium and the lithium CPS. An increase of the hydrogen isotope interaction rate with the lithium CPS was observed under reactor irradiation.     

Physosmotic Induction of Chondrogenic Maturation Is TGF-β Dependent and Enhanced by Calcineurin Inhibitor FK506

Increasing extracellular osmolarity 100 mOsm/kg above plasma level to the physiological levels for cartilage induces chondrogenic marker expression and the differentiation of chondroprogenitor cells. The calcineurin inhibitor FK506 has been reported to modulate the hypertrophic differentiation of primary chondrocytes under such conditions, but the molecular mechanism has remained unclear. We aimed at clarifying its role. Chondrocyte cell lines and primary cells were cultured under plasma osmolarity and chondrocyte-specific in situ osmolarity (+100 mOsm, physosmolarity) was increased to compare the activation of nuclear factor of activated T-cells 5 (NFAT5). The effects of osmolarity and FK506 on calcineurin activity, cell proliferation, extracellular matrix quality, and BMP- and TGF-β signaling were analyzed using biochemical, gene, and protein expression, as well as reporter and bio-assays. NFAT5 translocation was similar in chondrocyte cell lines and primary cells. High supraphysiological osmolarity compromised cell proliferation, while physosmolarity or FK506 did not, but in combination increased proteoglycan and collagen expression in chondrocytes in vitro and in situ. The expression of the TGF-β-inducible protein TGFBI, as well as chondrogenic (SOX9, Col2) and terminal differentiation markers (e.g., Col10) were affected by osmolarity. Particularly, the expression of minor collagens (e.g., Col9, Col11) was affected. The inhibition of the FK506-binding protein suggests modulation at the TGF-β receptor level, rather than calcineurin-mediated signaling, as a cause. Physiological osmolarity promotes terminal chondrogenic differentiation of progenitor cells through the sensitization of the TGF-β superfamily signaling at the type I receptor. While hyperosmolarity alone facilitates TGF-β superfamily signaling, FK506 further enhances signaling by releasing the FKBP12 break from the type I receptor to improve collagenous marker expression. Our results help explain earlier findings and potentially benefit future cell-based cartilage repair strategies.     

Gold nanoparticle conjugated poly(p-phenylene-β-cyclodextrin)-graft-poly(ethylene glycol) for theranostic applications

Fluorescent conjugated polymers gained interest in the last decades for both imaging and targeting tumor cells for the purpose of diagnosis and treatment of cancer. In the light of this objective conjugated poly(p-phenylene) possessing β-cyclodextrin (β-CD) units in the main chain and poly(ethylene glycol) side chains is used as an imaging and therapeutic agent to target U87 and Vero cells. Additionally, imaging quality and therapy efficiency of the bare graft copolymer and its gold nanoparticle (AuNP) conjugated form were investigated and compared. It is observed that β-CD is effective not only for the imaging of the tumor cells, but also as a radiotherapy agent. Conjugation of the polymer with the AuNPs provides significant improvement in the therapeutic efficiency. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47250.     

Breakthrough Analysis OF H 2 S removal on CU-V-MO,CU-V,and CU-MO mixed oxides

Kinetic studies carried out for the sorption of H 2 S in the presence and absence of hydrogen on Cu-V-Mo, Cu-V, and Cu-Mo mixed oxides gave detailed information about the reaction sequences. Formation of SO 2 even in the presence of hydrogen at the initial stages of the sorption process showed the partial reduction of the metal oxides prior to the sulfidation step. A sorption experiment carried out with Cu-Mo mixed oxide gave incomplete sulfidation of molybdenum, whereas with Cu-V mixed oxide complete sulfidation was obtained. Predictions of the breakthrough curves by the deactivation model showed good agreement with the experimental results.     

PERFORMANCE OF ACIDIC MCM-LIKE ALUMINOSILICATE CATALYSTS IN PYROLYSIS OF POLYPROPYLENE

Mesoporous aluminosilicate catalysts having different Al/Si ratios were synthesized following a hydrothermal synthesis route and using different aluminum sources, such as aluminum nitrate and aluminum isopropoxide. These mesoporous materials have high surface areas, in the range of 520–1001 m²/g, and exhibit Type IV nitrogen adsorption isotherms. EDS and ²⁷Al MAS NMR results showed that aluminum was incorporated more effectively into the structure of the catalyst forming a tetrahedral framework when aluminum nitrate was used as the aluminum source. The activities of these catalysts in the polypropylene pyrolysis reaction were tested in a TGA apparatus. Results showed a marked reduction in the degradation temperature in the presence of aluminosilicate catalysts. The activation energy of degradation was 172 kJ/mole without any catalyst. However, using the mesoporous aluminosilicate catalysts synthesized by using aluminum nitrate as the aluminum source, activation energy of the degradation reaction decreased to values of about 24–28 kJ/mole.     

On the nature of active sites in Fe/ZSM-5 catalysts for NOx abatement

Fe/ZSM-5 catalysts with high Fe loading (Fe/Al1) have been prepared by sublimation of FeCl₃ onto H-ZSM-5 samples of different Si/Al ratios. They catalyze NO_x reduction with hydrocarbons in an excess of O₂ and H₂O. TPR shows that the Fe in the zeolite cavities is different from Fe₂O₃ particles. Naked Fe³⁺ ions are absent; oxo-ions, which are equally well reducible by CO and H₂, prevail. A minority of the Fe complexes lose oxygen upon mere heating to 500°C; some of the reduced sites are reoxidized only by N₂O. The population of oxo-complexes that lose oxygen by heating depends on the Si/Al ratio, this dependence is in qualitative agreement with the model of (2+) charged binuclear ions [HO–Fe–O–Fe–OH]²⁺. Upon reacting with NO, the bridging O atom is transferred and NO₂ is formed. This step is not rate limiting for active catalysts with high Al/Si ratio and high Fe loading, but it becomes critical with zeolites of low Al/Si ratio.     

An Earned Schedule-based regression model to improve cost estimate at completion

Traditional Earned Value Management (EVM) index-based methods for Cost Estimate at Completion (CEAC) of an ongoing project have been known for their limitations inherent with both the assumption that past EVM data is the best available information and early-stage unreliability.     

Dynamic analysis of adsorption equilibrium and rate parameters of reactants and products in MTBE,ETBE and TAME production

Adsorption equilibrium constants of ethanol, methanol, isobutylene, isoamylenes (2M2B, 2M1B), MTBE and TAME on Amberlyst 15 catalyst were evaluated from the packed bed moment technique. Adsorption equilibrium constants of alcohols were found to be two orders of magnitude greater than the adsorption equilibrium constants of i-olefins and the corresponding tertiary ethers. However, their apparent heat of adsorption values are quite low (-6,7 kJ/mol and ?8.3 kJ/mol for methanol and ethanol, respectively). Among the i-olefins, isobutylene gave the highest adsorption equilibrium constant and the heat of adsorption (-54.2 kJ/mol The adsorption equilibrium constant of 2M2B on a catalyst, which was pretreated with ethanol, was about three times greater than the corresponding value obtained on fresh catalyst. Second moment analysis indicated that diffusion resistance in both macropores and microspheres of the catalyst are equally significant.     

Gold nanoparticle ensembles as heaters and actuators: melting and collective plasmon resonances

We describe the peculiar conditions under which optically driven gold nanoparticles (NPs) can significantly increase temperature or even melt a surrounding matrix. The heating and melting processes occur under light illumination and involve the plasmon resonance. For the matrix, we consider water, ice, and polymer. Melting and heating the matrix becomes possible if a nanoparticle size is large enough. Significant enhancement of the heating effect can appear in ensembles of NPs due to an increase of a volume of metal and electric-field amplification.     

Mechanism of TAME and TAEE synthesis from diffuse–reflectance FTIR analysis

Diffuse–reflectance FTIR results obtained with tert-amyl-methyl-ether (TAME), ethanol, methanol, i-amylenes and mixtures of i-amylenes with alcohols supported a Langmuir–Hinshelwood type reaction mechanism involving adsorbed i-amylene molecules, which form a bridged structure between the adsorbed alcohols and the SO₃H sites of Amberlyst-15. Number of available sites involved in the adsorption of i-olefins is drastically decreased with an increase in alcohol concentration. The reaction rate model, which was proposed basing on the DRIFTS results, was shown to give good agreement with the published initial rate data for TAEE synthesis. The rate of tert-amyl-ethyl-ether (TAEE) formation was found to give a rather sharp maximum at an ethanol activity smaller than 0.1.