Enantioselective Isocyanide-based Multicomponent Reaction with Alkylidene Malonates and Phenols.

A highly enantioselective isocyanide-based multicomponent reaction catalyzed by a chiral N,N'-dioxide/MgII complex was reported. A wide range of substrates were tolerated in this reaction, including alkyl- and aryl-substituted isocyanides with alkylidene malonates and various phenols, affording the corresponding phenoxyimidate products in good to excellent yields (up to 94% yield) with good to excellent enantioselectivities (up to 95.5:4.5 er). A catalytic cycle and transition state were proposed to rationalize the reaction process and enantiocontrol.

Assessment of AlN/Mg-8Al Composites Reinforced with In Situ and/or Ex Situ AlN Particles.

In this paper, 8.2AlN/Mg-8Al composites reinforced with in situ and/or ex situ AlN particles have been synthesized. The in situ-formed AlN particles are nano-sized, performing as particle chains. It has been clarified that the in situ AlN particles are more efficient than ex situ particles for the enhancement of mechanical properties. The in situ-prepared composite exhibits improved density, hardness and compressive strength compared to the ex situ ones. This work may be referred to for designing particle-reinforced Mg composites by various methods.

Positive correlation between human exposure to organophosphate esters and gastrointestinal cancer in patients from Wuhan, China.

As kinds of endocrine disruptors, organophosphate esters (OPEs) pollution in the environment had received increasing attention recently. Food and water intake were two important exposure pathways for OPEs. However, the studies about the potential association between OPEs and gastrointestinal cancer were limited. This study investigated the possible association between OPEs and gastrointestinal cancer. All cancer patients were diagnosed with gastrointestinal cancer from a Grade 3 A hospital in Wuhan, China, while the control group was non-cancer healthy persons. The results showed that 6 OPEs were found in the control samples, while 8 in the samples from patients with gastrointestinal cancer. The detection frequencies of OPEs in gastrointestinal cancer patients were significantly higher than those in the control group (p < 0.05 or p < 0.01), except for triethyl phosphate (TEP) and tris (methylphenyl) phosphate (TMPP) in the gastric cancer group. The concentrations of OPEs in the control group were significantly lower than those in the gastric cancer group and colorectal cancer group (p < 0.01). In the control group and gastrointestinal cancer group, TEP was the dominant pollutant. Correlation analysis found that concentrations of TEP, tris(2-chloroisopropyl) phosphate (TCIPP), triphenyl phosphate (TPHP), TMPP, tris(2-ethylhexyl) phosphate (TEHP), and 2-ethylhexyl diphenyl phosphate (EHDPP) were associated with gastric cancer (p < 0.01), and concentrations of TEP, TCIPP, TPHP, TMPP and TEHP were associated with colorectal cancer (p < 0.01). A cluster analysis divided the 34 patients with gastric cancer and 40 patients with colorectal cancer in four groups. The results showed that the elderly male patients with gastric cancer were more sensitive to the exposure of EHDPP, while the TEP exposure was more sensitive to the relatively young gastrointestinal cancer patients. These findings indicated that OPEs might play a role in developing gastrointestinal cancer.

Evolution and Strengthening Effects of the Heat-Resistant Phases in Al-Si Piston Alloys with Different Fe/Ni Ratios.

The evolution of three major heat-resistant phases (δ-Al3CuNi, γ-Al7Cu4Ni, T-Al9FeNi) and its strengthening effects at high temperature in Al-Si piston alloys with various Fe/Ni ratios were studied using field emission scanning electron microscope (FE-SEM), electron probe microanalysis (EPMA), and X-ray diffraction (XRD). With the increase of Fe/Ni ratios, the heat-resistant phases begin to evolve in category, morphology, and distribution. The results show that a suitable Fe/Ni ratio will cause the T-Al9FeNi phase to appear and form a closed or semi-closed network with δ-Al3CuNi and γ-Al7Cu4Ni phases instead of the originally isolated heat-resistant phases. As a result, the ultimate tensile strength of the optimized alloy reached 106 MPa with a Fe/Ni ratio of 0.23, which was 23.3% higher than that of base alloy at 350 °C, which is attributed to the fact that a closed or semi-closed network microstructure is advantageous to the bearing of mechanical loads. This work may provide useful ideas for the development of high temperature resistant piston alloys.

N-doped carbon coated Mn3O4/PdCu nanocomposite as a high-performance catalyst for 4-nitrophenol reduction.

This paper reports the chemical synthesis of highly-active Mn3O4/PdCu nanocomposites coated with N-doped carbon (NC) shell using polydopamine (PDA) as the carbon source, which provides high specific surface area and pore volume. The structure and morphology of Mn3O4/PdCu@NC nanocomposites were systematically studied. Taking advantage of the synergistic effects of PdCu alloy and Mn3O4 support, the Mn3O4/PdCu@NC catalyst exhibited an outstanding activity toward the reduction of 4-nitrophenol (4-NP), in comparison to Mn3O4/PdM@NC (M = Ni, Au, Ag), Mn3O4/PdCu@PDA, and commercial Pd/C catalyst. Owing to the protection by NC shell, the as-prepared catalyst showed stable conversion efficiency of up to 90% over ten successive cycles. Considering 4-NP as one of the important organic pollutants from industrial production, the effects of various inorganic and organic species on the catalytic efficiency were further tested and most of them had negligible impact. This strategy of utilizing an N-doped carbon shell could be extended to obtain PdCu alloys supported on other metal oxides, making it applicable for applications in treatment of environmental pollutants.