A metal-organic cage-derived cascade antioxidant nanozyme to mitigate renal ischemia-reperfusion injury.

In the field of contemporary medicine, inflammation has emerged as a significant concern in global public health. Among the current anti-inflammatory strategies, nanozymes possess distinctive advantages and demonstrate unexpected efficacy in combating inflammation. However, the indeterminate structures and limited enzyme-like activity exhibited by most developed nanozymes impede their clinical translation and therapeutic effectiveness. In this paper, we developed a nanozyme derived from a well-defined metal-organic cage (MOC). The oxidized MOC (MOC-O), containing pyridine nitrogen oxide moieties, exhibited effective cascade superoxide dismutase (SOD) and catalase (CAT)-like activities for scavenging reactive oxygen species (ROS). This ROS scavenging ability was confirmed through flow cytometry analysis using DCFH-DA in a hypoxia/reoxygenation (H/R) model, where MOC-O significantly alleviated oxidative stress. Furthermore, the administration of MOC-O resulted in preserved renal function during renal ischemia-reperfusion (I/R) injury due to downregulated oxidative stress levels and reduced cell apoptosis.

Pd-Sn Alloy Catalysts for Direct Synthesis of Hydrogen Peroxide from H2 and O2 in a Microchannel Reactor.

Direct synthesis of hydrogen peroxide (DSHP) from H2 and O2 offers a promising alternative to the present commercial anthraquinone method, but it still faces the challenges of low H2O2 productivity, low stability of catalysts, and high risk of explosion. Herein, by loading in a microchannel reactor, the as-synthesized Pd-Sn alloy materials exhibit high catalytic activity for H2O2 production, presenting a H2O2 productivity of 3124 g kgPd-1 h-1. The doped Sn atoms on the surface of Pd not only facilitate the release of H2O2 but also effectively slow down the deactivation of catalysts. Theoretical calculations demonstrate that the Pd-Sn alloy surface has the property of antihydrogen poisoning, showing higher activity and stability than pure Pd catalysts. The deactivation mechanism of the catalyst was elucidated, and the online reactivation method was developed. In addition, we show that the long-life Pd-Sn alloy catalyst can be achieved by supplying an intermittent flow of hydrogen gas. This work provides guidance on how to prepare high performance and stable Pd-Sn alloy catalysts for the continuous and direct synthesis of H2O2.

Photoluminescence properties of a novel phosphor CaB2O4:Eu3+ under NUV excitation.

The new borate phosphor CaB(2)O(4):Eu(3+) was synthesized by solid-state method and their photoluminescence properties were investigated. The results show that the pure phase of CaB(2)O(4) could be available at 900 degrees C, CaB(2)O(4):Eu(3+) phosphor could be effectively excited by the near ultraviolet light (NUV) (392 nm), and the luminescent intensity of CaB(2)O(4):Eu(3+) phosphor reached to the highest when the doped-Eu(3+) content was 4 mol%. The emission spectra of CaB(2)O(4):Eu(3+) phosphor could exhibit red emission at 612 nm and orange emission at 588 nm, which are ascribed to the (5)D(0)-(7)F(2) and (5)D(0)-(7)F(1) transitions of Eu(3+) ions.

[Synthesis and photoluminescence of Zn(1-x) Mo(1-y)Si(y)O4 : Eu+ phosphor].

The phosphors Zn(1-x) Mo(1-y)Si(y)O4 : Eu(x)3+ (0.05 < or = x < or = 0.30, 0 < or = y < or = 0.09) were prepared by solid state reaction technique at 800 degrees C. The powder X-ray diffraction patterns of the samples show that the phosphors are of single phase and the doping Eu ion and Si ion have little influence on the host structure. The effects of flux and calcination temperature on the luminescent properties of the phosphors were investigated. The results showed that flux content has effects on the luminescent properties, and the optimized flux content and the best calcination temperature is 4% and 800 degrees C, respectively. The presence of the Na+ ion strengthens the photoluminescence intensity of the phosphors. The addition of Na+ ions balanced the charge in samples, enhanced the luminescence intensity of samples, and the luminescence intensity reached the maximum when the doping concentration of Na2 CO3 was 4 Wt%. The luminescent properties of Zn0.80 Mo(1-y)Si(y)O4 : Eu(0.20)3+ were studied by the excitation and emission spectra, and the influence of Eu3+ and Si4+ concentrations on the luminescent property was discussed. As the calcination temperature rises from 700 to 800 degrees C, the emission intensity increases due to the improvement of crystallinity. The excitation spectra consist of a broad band and a series of narrow lines, and the narrow lines are attributed to the intrinsic transition from 7FJ (J = 1-4) to 5DJ (J = 0, 1) of Eu3+. It was found that the PL emission intensity was enhanced with the increase in the Eu3+ doping ratio and reached a maximum value at x = 0.20. The result indicated that Zn(1-x)Mo(1-y)Si(y)O4 : Eu(x)3+ phosphors can be excited effectively at 393 and 464 nm light. The presence of the Si4+ ion strengthens the photoluminescence intensity of the phosphors and the strong red emission lines at 616 nm correspond to the forced electric dipole 5D0 --> F2 transitions on Eu3+. Compared with Y2O2S : 0.05 Eu3+, the obtained Zn0.80Mo0.97Si0.03O4 : Eu(0.20)3+ phosphor shows an enhanced red emission under 393 nm excitation and the emission intensity of Y2O2S : 0.05Eu3+ is only 50% of that of Zn0.80Mo0.97Si0.03O4 : Eu(0.20)3+. The optical properties suggest that Zn0.80Mo0.97Si0.03O4 : Eu(0.20)3+ is an efficient red emitting phosphor for light emitting diode (LED) applications.

Adsorption of lead and mercury by rice husk ash.

An attempt at the use of rice husk ash, an agricultural waste, as an adsorbent for the adsorption of lead and mercury from aqueous water is studied. Studies are carried out as a function of contact times, ionic strength, particle size, and pH. Rice husk ash is found to be a suitable adsorbent for the adsorption of lead and mercury ions. The Bangham equation can be used to express the mechanism for adsorption of lead and mercury ions by rice husk ash. Its adsorption capability and adsorption rate are considerably higher and faster for lead ions than for mercury ions. The finer the rice husk ash particles used, the higher the pH of the solution and the lower the concentration of the supporting electrolyte, potassium nitrate solution, the more lead and mercury ions absorbed on rice husk ash. Equilibrium data obtained have been found to fit both the Langmuir and Freundlich adsorption isotherms.