Irradiation-induced precipitation modelling of ferritic steels

In high strength low alloy (HSLA) steels typically used in reactor pressure vessels (RPV), irradiation-induced microstructure changes affect the performance of the components. One such change is precipitation hardening due to the formation of solute clusters and/or precipitates which form as a result of irradiation-enhanced solute diffusion and thermodynamic stability changes. The other is irradiation-enhanced tempering which is a result of carbide coarsening due to irradiation-enhanced carbon diffusion. Both effects have been studied using a recently developed Monte Carlo based precipitation kinetics simulation technique and modelling results are compared with experimental measurements. Good agreements have been achieved

Effects of Solvation on the Framework of a Breathing Copper MOF Employing a Semirigid Linker

A semirigid di-1,2,4-triazole ligand leads to formation of the MOF [Cu₂(<b>L</b>)₂(SO₄)­(Br)₂]·<i>x</i>H₂O (<b>1</b>). The framework structure of <b>1</b> flexes reversibly upon removal or addition of water to form semihydrated ([Cu₂(<b>L</b>)₂(SO₄)­(Br)₂]·4H₂O) and dehydrated ([Cu₂(<b>L</b>)₂(SO₄)­(Br)₂]·0H₂O) MOFs, <b>1′</b> and <b>1″</b>, respectively. Single-crystal X-ray analysis demonstrated that the 2-butene subunit of the ligand rotates between two positions for <b>1</b> and <b>1′</b>, causing a change in the solvent-accessible volume in the framework. This double hinge within the semirigid ligand is a built-in breathing mechanism and suggests a novel approach for general synthesis of breathing MOFs

Effects of Solvation on the Framework of a Breathing Copper MOF Employing a Semirigid Linker

A semirigid di-1,2,4-triazole ligand leads to formation of the MOF [Cu₂(<b>L</b>)₂(SO₄)­(Br)₂]·<i>x</i>H₂O (<b>1</b>). The framework structure of <b>1</b> flexes reversibly upon removal or addition of water to form semihydrated ([Cu₂(<b>L</b>)₂(SO₄)­(Br)₂]·4H₂O) and dehydrated ([Cu₂(<b>L</b>)₂(SO₄)­(Br)₂]·0H₂O) MOFs, <b>1′</b> and <b>1″</b>, respectively. Single-crystal X-ray analysis demonstrated that the 2-butene subunit of the ligand rotates between two positions for <b>1</b> and <b>1′</b>, causing a change in the solvent-accessible volume in the framework. This double hinge within the semirigid ligand is a built-in breathing mechanism and suggests a novel approach for general synthesis of breathing MOFs

Mechanism of Arctigenin-Induced Specific Cytotoxicity against Human Hepatocellular Carcinoma Cell Lines: Hep G2 and SMMC7721

<div><p>Arctigenin (ARG) has been previously reported to exert high biological activities including anti-inflammatory, antiviral and anticancer. In this study, the anti-tumor mechanism of ARG towards human hepatocellular carcinoma (HCC) was firstly investigated. We demonstrated that ARG could induce apoptosis in Hep G2 and SMMC7721 cells but not in normal hepatic cells, and its apoptotic effect on Hep G2 was stronger than that on SMMC7721. Furthermore, the following study showed that ARG treatment led to a loss in the mitochondrial out membrane potential, up-regulation of Bax, down-regulation of Bcl-2, a release of cytochrome c, caspase-9 and caspase-3 activation and a cleavage of poly (ADP-ribose) polymerase in both Hep G2 and SMMC7721 cells, suggesting ARG-induced apoptosis was associated with the mitochondria mediated pathway. Moreover, the activation of caspase-8 and the increased expression levels of Fas/FasL and TNF-α revealed that the Fas/FasL-related pathway was also involved in this process. Additionally, ARG induced apoptosis was accompanied by a deactivation of PI3K/p-Akt pathway, an accumulation of p53 protein and an inhibition of NF-κB nuclear translocation especially in Hep G2 cells, which might be the reason that Hep G2 was more sensitive than SMMC7721 cells to ARG treatment.</p></div

Effects of TiO₂ in Low Temperature Propylene Epoxidation Using Gold Catalysts

Propylene epoxidation with molecular oxygen has been proposed as a green and alternative process to produce propylene oxide (PO). In order to develop catalysts with high selectivity, high conversion, and long stability for the direct propylene epoxidation with molecular oxygen, understanding of catalyst structure and reactivity relationships is needed. Here, we combined atomic layer deposition and deposition precipitation to synthesize series of well-defined Au-based catalysts to study the catalyst structure and reactivity relationships for propylene epoxidation at 373 K. We showed that by decorating TiO₂ on gold surface the inverse TiO₂/Au/SiO₂ catalysts maintained ∼90% selectivity to PO regardless of the weight loading of the TiO₂. The inverse TiO₂/Au/SiO₂ catalysts exhibited improved regeneration compared to Au/TiO₂/SiO₂. The inverse TiO₂/Au/SiO₂ catalysts can be regenerated in 10% oxygen at 373 K, while the Au/TiO₂/SiO₂ catalysts failed to regenerate at as high as 473 K. Combined characterizations of the Au-based catalysts by X-ray absorption spectroscopy, scanning transmission electron microscopy, and UV–vis spectroscopy suggested that the unique selectivity and regeneration of TiO₂/Au/SiO₂ are derived from the site-isolated Ti sites on Au surface and Au–SiO₂ interfaces which are critical to achieve high PO selectivity and generate only coke-like species with high oxygen content. The high oxygen content coke-like species can therefore be easily removed. These results indicate that inverse TiO₂/Au/SiO₂ catalyst represents a system capable of realizing sustainable gas phase propylene epoxidation with molecular oxygen at low temperature

Convenient approach to chiral 4-monosubstituted 1,3-oxazolidine-2-thiones

<p>Chiral 4-monosubstituted 1,3-oxazolidine-2-thiones are regarded as one of the modified version of Evans auxiliaries in asymmetric aldol condensation, which can generate two adjacent chiral carbon centers in one time They have advantages over Evans auxiliaries in some aspects, however, their application is highly limited by their preparation approaches as toxic or flammable chemicals are involved. Here, a mild and applicable procedure for preparing the chiral oxazolidine-2-thione auxiliaries has been developed in this article. Potassium ethylxanthate and the corresponding chiral amino alcohols as the starting material in absolute ethanol are mixed and the mixture are heated under reflux for 1 h in open air to provide 1,3-oxazolidine-2-thiones chiral auxiliaries in moderate to excellent yields.</p

Organoboron- and Cyano-Grafted Solid Polymer Electrolytes Boost the Cyclability and Safety of High-Voltage Lithium Metal Batteries

Solid-state polymer electrolytes (SPEs) are deemed as a class of sought-after candidates for high-safety and high-energy-density solid-state lithium metal batteries, but their low ionic conductivity, narrow electrochemical windows, and severe interfacial deterioration limit their practical implementations. Herein, an organoboron- and cyano-grafted polymer electrolyte (PVNB) was designed using vinylene carbonate as the polymer backbone and organoboron-modified poly(ethylene glycol) methacrylate and acrylonitrile as the grafted phases, which may facilitate Li-ion transport, immobilize the anions, and enlarge the oxidation voltage window; therefore, the well-tailored PVNB exhibits a high Li-ion transference number (tLi+ = 0.86), a wide electrochemical window (>5 V), and a high ionic conductivity (σ = 9.24 × 10–4 S cm–1) at room temperature (RT). As a result, the electrochemical cyclability and safety of the Li|LiFePO4 and Li|LiNi0.8Co0.1Mn0.1O2 cells with in situ polymerization of PVNB are substantially improved by forming the stable organic–inorganic composite cathode electrolyte interphase (CEI) and the Li3N–LiF-rich solid electrolyte interphase (SEI)

Cytotoxic effect of ARG on HCC cells and normal hepatic cells.

<p>(A) Hep G2, SMMC7721 and LO2 cell lines were treated with ARG at 5, 10, 20, 50, 80, 100 μM for 24 h. (B) Hep G2 cells were exposed to a gradient dose of ARG for the indicated time period and IC₅₀ value was calculated for each time point. Cell viability inhibition was assessed by MTT assay. Each value is the mean ± SD of five independent experiments. *p<0.05, **p<0.01, ***p<0.0001 significant difference between control and ARG-treated cells in each cell line, as analyzed by Dunnett’s Multiple Comparion Test.</p

Organoboron- and Cyano-Grafted Solid Polymer Electrolytes Boost the Cyclability and Safety of High-Voltage Lithium Metal Batteries

Solid-state polymer electrolytes (SPEs) are deemed as a class of sought-after candidates for high-safety and high-energy-density solid-state lithium metal batteries, but their low ionic conductivity, narrow electrochemical windows, and severe interfacial deterioration limit their practical implementations. Herein, an organoboron- and cyano-grafted polymer electrolyte (PVNB) was designed using vinylene carbonate as the polymer backbone and organoboron-modified poly(ethylene glycol) methacrylate and acrylonitrile as the grafted phases, which may facilitate Li-ion transport, immobilize the anions, and enlarge the oxidation voltage window; therefore, the well-tailored PVNB exhibits a high Li-ion transference number (tLi+ = 0.86), a wide electrochemical window (>5 V), and a high ionic conductivity (σ = 9.24 × 10–4 S cm–1) at room temperature (RT). As a result, the electrochemical cyclability and safety of the Li|LiFePO4 and Li|LiNi0.8Co0.1Mn0.1O2 cells with in situ polymerization of PVNB are substantially improved by forming the stable organic–inorganic composite cathode electrolyte interphase (CEI) and the Li3N–LiF-rich solid electrolyte interphase (SEI)

Organoboron- and Cyano-Grafted Solid Polymer Electrolytes Boost the Cyclability and Safety of High-Voltage Lithium Metal Batteries

Solid-state polymer electrolytes (SPEs) are deemed as a class of sought-after candidates for high-safety and high-energy-density solid-state lithium metal batteries, but their low ionic conductivity, narrow electrochemical windows, and severe interfacial deterioration limit their practical implementations. Herein, an organoboron- and cyano-grafted polymer electrolyte (PVNB) was designed using vinylene carbonate as the polymer backbone and organoboron-modified poly(ethylene glycol) methacrylate and acrylonitrile as the grafted phases, which may facilitate Li-ion transport, immobilize the anions, and enlarge the oxidation voltage window; therefore, the well-tailored PVNB exhibits a high Li-ion transference number (tLi+ = 0.86), a wide electrochemical window (>5 V), and a high ionic conductivity (σ = 9.24 × 10–4 S cm–1) at room temperature (RT). As a result, the electrochemical cyclability and safety of the Li|LiFePO4 and Li|LiNi0.8Co0.1Mn0.1O2 cells with in situ polymerization of PVNB are substantially improved by forming the stable organic–inorganic composite cathode electrolyte interphase (CEI) and the Li3N–LiF-rich solid electrolyte interphase (SEI)