Simulation of radioactivation and chlorination reaction behavior for Zircaloy-4 and Zirlo cladding hull wastes

Radioactivation of Zircaloy-4 (Zry-4) and Zirlo cladding hulls after 55 GWD/tU burn-up and 10 years of cooling was simulated using the ORIGEN-S code. The simulation results revealed that ¹²⁵Sb and ⁶⁰Co are major contributors of both radioactivity and decay heat in the case of the Zry-4 hulls. For the Zirlo hulls, ^93mNb and ¹²⁵Sb consisted 82.2% of radioactivity while ¹²⁵Sb and ⁶⁰Co emitted 77.9% of decay heat. Although the radioactivity between the Zry-4 (1.17 Ci for 1 kg of fresh Zry-4) and Zirlo (1.38 Ci for 1 kg of fresh Zirlo) hulls was not significantly different, decay heat of the activated Zry-4 hulls (8.58 mW) was much larger than 1.62 mW of the activated Zirlo hulls. This gap might have come from the different major constituents of Zry-4 (Zr, Sn, Fe, and Cr) and Zirlo (Zr, Sn, Nb, and Fe) resulting in different radioactive nuclides after radioactivation. Chlorination reaction behavior of the activated Zry-4 and Zirlo hulls was performed using the HSC chemistry code. Constituents of recovered ZrCl₄ were investigated via changes of Gibbs free energy and boiling points of resulting chlorides. The calculation results suggested that radioactivity and decay heat might decrease by 49.0 and 81.8%, respectively, in the ZrCl₄ recovered from the activated Zry-4 hulls. In the case of Zirlo, it was expected that radioactivity and decay heat might decrease by 11.6 and 13.0%, respectively, after the chlorination reaction. Effect of cooling time on radioactivity and decay heat was also investigated.     

High-quality polythiophene films prepared by electropolymerization of thiophene in BF3-ethyl ether solution

Polythiophene films have been deposited on a platinum electrode surface by direct oxidation of thiophene in BF₃-ethyl ether solution containing a controlled amount of water (5 mM). The electric and mechanical properties of the films were studied. Experimental results demonstrated that the films prepared at low applied potentials were semiconductors with conductivities in the order of 10^?1 s cm^?1. The strengths of these films were high and comparable to those of some widely used engineering plastics such as poly(propylene) and poly(vinyl acetate). The conductivities of the PT films varied with the value of applied potential used for electrolysis and passed through a maximum of 19.13 s cm^?1 at +1.6 V. At a given applied potential, low experimental temperature, and monomer concentration led to formation of films with high quality. © 1995 John Wiley & Sons, Inc.     

Studies of Photon Correlation Spectroscopy of the Microemulsion of H2O/Tween 80/Benzene Derivative

The microemulsion of the H₂O/Tween 80/benzene derivative (C₆H₆, CH₃C₆H₅, NO₂C₆H₅ and NH₂C₆H₅) was investigated by the technique of Photon correlation spectroscopy. Autocorrelation data were measured at 90 scattering angle and were analyzed by using a quadratic fit and linear fit. The quadratic fit was found to describe all Properties better than the linear fit, and thus the linear fit was limited to the region of very short sampling time. When the amount of benzene derivative added to the sample solution was lower than V_max, the Z-average mean radius, <r>_z, and the polydispersit Y, μ2/Γ², increased as the amount of benzene derivative was increased. When the amount of benzene derivative was larger than V_max, the aqueous and organic phases separated and the <r> z, and μ₂/Γ² of all phases remained constant. Emulsification did not occur in the organic phase of the H₂O/Tween 80/aniline system. When we adjusted the Tween 80 concentration, it was found that <r>z and μ₂/Γ² decreased as the Tween 80 concentration increased.     

Chemoselective synthesis of 1-alkyl-4-(4-amino-2,6-dichlorophenoxy)-5-halopyridazin-6-ones

Some 1-alkyl-4-(4-amino-2,6-dichlorophenoxy)-5-halopyridazin-6-ones were synthesized chemoselectively from 1-alkyl-4,5-dihalopyridazin-6-ones and 4-amino-2,6-dichlorophenol via a fluoride ion-assisted reaction.     

Continuous fabrication of biocatalyst immobilized microparticles using photopolymerization and immiscible liquids in microfluidic systems

We report a novel technique for manufacturing polymeric microparticles containing biocatalysts by the behavior of immiscible liquids in microfluidic systems and in situ photopolymerization. The approach utilizes a UV-polymerizable hydrogel/enzyme solution and an immiscible oil solution. The oil and hydrogel solutions form emulsions in pressure-driven flow in microchannels at high values of the dimensionless capillary number (Ca). The resultant hydrogel droplets are then polymerized in situ via exposure to 365 nm UV light. This technique allows for the generation of monodisperse particles whose size can be controlled by the regulation of flow rates. In addition, both manufacturing microparticles and immobilizing biocatalysts can be performed simultaneously and continuously.     

Harmine Hydrochloride Mediates the Induction of G2/M Cell Cycle Arrest in Breast Cancer Cells by Regulating the MAPKs and AKT/FOXO3a Signaling Pathways

Breast cancer (BC) is one of the most common causes of death among women worldwide. Recently, interest in novel approaches for BC has increased by developing new drugs derived from natural products with reduced side effects. This study aimed to treat BC cells with harmine hydrochloride (HMH) to identify its anticancer effects and mechanisms. HMH treatment suppressed cell growth, migration, invasion, and colony formation in MCF-7 and MDA-MB-231 cells, regardless of the hormone signaling. It also reduced the phosphorylation of PI3K, AKT, and mTOR and increased FOXO3a expression. Additionally, HMH treatment increased p38 phosphorylation in MCF-7 cells and activated c-Jun N-terminal kinase (JNK) phosphorylation in MDA-MB-231 cells in a dose-dependent manner, where activated p38 and JNK increased FOXO3a expression. Activated FOXO3a increased the expression of p53, p21, and their downstream proteins, including p-cdc25, p-cdc2, and cyclin B1, to induce G2/M cell cycle arrest. Furthermore, HMH inhibited the PI3K/AKT/mTOR pathway by significantly reducing p-AKT expression in combination with LY294002, an AKT inhibitor. These results indicate that mitogen-activated protein kinases (MAPKs) and AKT/FOXO3a signaling pathways mediate the induction of cell cycle arrest following HMH treatment. Therefore, HMH could be a potential active compound for anticancer bioactivity in BC cells.     

Microbiota-derived lactate promotes hematopoiesis and erythropoiesis by inducing stem cell factor production from leptin receptor+ niche cells

Although functional interplay between intestinal microbiota and distant sites beyond the gut has been identified, the influence of microbiota-derived metabolites on hematopoietic stem cells (HSCs) remains unclear. This study investigated the role of microbiota-derived lactate in hematopoiesis using mice deficient in G-protein-coupled receptor (Gpr) 81 (Gpr81^−/−), an established lactate receptor. We detected significant depletion of total HSCs in the bone marrow (BM) of Gpr81^−/− mice compared with heterogenic (Gpr81^+/−) mice in a steady state. Notably, the expression levels of stem cell factor (SCF), which is required for the proliferation of HSCs, decreased significantly in leptin receptor-expressing (LepR⁺) mesenchymal stromal cells (MSCs) around the sinusoidal vessels of the BM from Gpr81^−/− mice compared with Gpr81^+/− mice. Hematopoietic recovery and activation of BM niche cells after irradiation or busulfan treatment also required Gpr81 signals. Oral administration of lactic acid-producing bacteria (LAB) activated SCF secretion from LepR⁺ BM MSCs and subsequently accelerated hematopoiesis and erythropoiesis. Most importantly, LAB feeding accelerated the self-renewal of HSCs in germ-free mice. These results suggest that microbiota-derived lactate stimulates SCF secretion by LepR⁺ BM MSCs and subsequently activates hematopoiesis and erythropoiesis in a Gpr81-dependent manner.Subject terms: Immunology, Stem-cell research     

Biocomposites Containing Silver Nanoparticles for Biomedical Applications

Journal of Cluster Science - Clinically, implant-related bone infections are a serious concern as they reduce the success rate of grafting techniques and increases the risk of morbidity. Clinicians...