Phosphotungstic Acid-treated Picrosirius Red Staining Improves Whole-slide Quantitative Analysis of Collagen in Histological Specimens

We tried to prevent nonspecific nuclear staining (NS-NS) of picrosirius red (PSR) staining by treating the specimens with one of the heteropoly acids phosphotungstic acid (PTA). We analyzed a total of 35 cases of non-cancerous liver tissue for fibrosis and NS-NS under PSR-alone, phosphomolybdic acid (PMA)-pretreated PSR (PMA + PSR), or PTA-pretreated PSR (PTA + PSR) condition. In addition, we analyzed the photosensitivity of PMA or PTA single stain specimens. PTA + PSR significantly suppressed NS-NS compared with PSR. The color of the specimens did not change into blue by 30 times the exposure to whole slide scanner (WSS) light. The PTA + PSR condition showed the highest correlation with the Ishak score (pathological evaluation of liver fibrosis) compared with other conditions. Furthermore, Sirius Red-positive percentage (SRP%) in PSR was increased in the NS-NS observed cases. SRP% in PMA + PSR was significantly affected by WSS light exposure time. Moreover, the deposition of non-polarized PSR-stained substances (NP-PSR+S) clinging to the collagen fibers potentially explains why SRP% seemed bigger under PSR than PTA + PSR. Our protocol enabled us to analyze the whole slide image of PSR staining by high magnification, which would contribute to the accurate analysis of collagen amount in the tissue sections.

Bifunctional 1,2,4-Triazole/12-Tungstophosphoric Acid Composite Nanoparticles for Biodiesel Production

Here, a composite nanoparticle with an acid-base bifunctional structure has been reported for the transesterification of rapeseed oil to produce biodiesel. Triazole-PWA (PWA = 12-tungstophosphoric acid) composite materials with a hexahedral structure are produced using the precipitation method, showing the average particle diameters of 200-800 nm. XPS and FT-IR analyses indicate well-defined chemical bonding of triazole moieties to the PWA. The functionalization and immobilization of PWAs are investigated due to strong interactions with triazole, which significantly improves the thermal stability and even surface area of the heteropoly acid. Furthermore, various ratios of triazole and PWAs are examined using NH₃-TPD and CO₂-TPD to optimize the bi-functionality of acidity and basicity. The prepared nanomaterials are evaluated during the transesterification of rapeseed oil with methanol to analyze the effect of triazole addition to PWAs according to the different ratios. Overall, the bifunctional triazole-PWA composite nanoparticles exhibit higher fatty acid methyl ester (FAME) conversions than pure PWA nanoparticles. The optimized catalyst with a triazole:PWA ratio of 6:1 exhibits the best FAME-conversion performance due to its relatively large surface area, balance of acidity, and strong basicity from the well-designed chemical nano-structure.

Enhanced Water Resistance and Catalytic Performance of Ru/TiO2 by Regulating Brønsted Acid and Oxygen Vacancy for the Oxidative Removal of 1,2-Dichloroethane and Toluene

The compositions of volatile organic compounds (VOCs) under actual industrial conditions are often complex; especially, the interaction of intermediate products easily leads to more toxic emissions that are harmful to the atmospheric environment and human health. Herein, we report a comparative investigation on 1,2-dichloroethane (1,2-DCE) and (1,2-DCE + toluene) oxidation over the Ru/TiO₂, phosphotungstic acid (HPW)-modified Ru/TiO₂, and oxygen vacancy-rich Ru/TiO_x catalysts. The doping of HPW successfully introduced the 1,2-DCE adsorption sites to promote its oxidation and exhibited outstanding water resistance. For the mixed VOCs, Ru/HPW-TiO₂ promoted the preferential and superfluous adsorption of toluene and resulted in the inhibition of 1,2-DCE degradation. Therefore, HPW modification is a successful strategy in catalytic 1,2-DCE oxidation, but Brønsted acid sites tend to adsorb toluene in the mixed VOC oxidation. The Ru/TiO_x catalyst exhibited excellent activity and stability in the oxidation of mixed VOCs and could inhibit the generation of byproducts and Cl₂ compared with the Ru/HPW-TiO₂ catalyst. Compared with the Brønsted acid modification, the oxygen vacancy-rich catalysts are significantly suitable for the oxidation of multicomponent VOCs.

One-Pot Synthesis of Benzo[4,5]imidazo[1,2-a]pyrimidin-2-ones Using a Hybrid Catalyst Supported on Magnetic Nanoparticles in Green Solvents

The conversion of soluble polyoxometalate into insoluble polyoxometalate is considered to be one of the major challenges in synthetic organic chemistry. Here, polyoxometalate was bonded to the salt part of an organic branch immobilized on the silica-coated Fe3 O4 nanoparticle and characterized using various techniques. The fabricated complex was used as a heterogeneous catalyst in a novel one-pot reaction for synthesis of benzo[4,5]imidazo[1,2-a]pyrimidin-2-ones using aromatic amines, dimethyl acetylenedicarboxylate (DMAD), derivatives of benzaldehyde and 2-aminobenzimidazole in water/ethanol as a green solvent. 21 derivatives of benzo[4,5]imidazo[1,2-a]pyrimidin-2-one were synthesized by this method and fully characterized. The high stability of the catalyst showed that it can be reused for 6 times without decreasing in activity. The combination of new synthetic method, new ferromagnetic heterogeneous nano-catalyst, green solvent and simple separation method were presented in this work.

Heteropoly Acid-Based Catalysts for Hydrolytic Depolymerization of Cellulosic Biomass

Cellulose is the most abundant source of biomass, which can be converted into monosaccharide or other chemical platform molecules for the sustainable production of chemicals and fuels. Acid catalysts can promote hydrolytic degradation of cellulose into valuable platform molecules, which is of great significance in the development of chemicals and biofuels. However, there are still some shortcomings and limitations of the catalysts for the hydrolytic degradation of cellulosic biomass. Heteropoly acid (HPA), as a green catalyst, seems to be more conducive to the degradation of cellulosic biomass due to its extreme acidity. HPAs can be designed in homogeneous and heterogeneous systems. Moreover, they can be easily separated from the products in both systems by a simple extraction process. According to the unique properties of HPAs (e.g., good solubility, high thermal stability, and strong acidity), using heteropoly acid-based catalysts to depolymerize and convert cellulose into value-added chemicals and biofuels has become one of the most remarkable processes in chemistry for sustainability. In this review, the characteristics, advantages, and applications of HPAs in different categories for cellulose degradation, especially hydrolysis hydrolytic degradation, are summarized. Moreover, the mechanisms of HPAs catalysts in the effective degradation of cellulosic biomass are discussed. This review provides more avenues for the development of renewed and robust HPAs for cellulose degradation in the future.

Synthesis of cyclic ethers by cyclodehydration of 1,n-diols using heteropoly acids as catalysts

Heteropoly acids were used as catalysts for cyclodehydration of various 1,n-diols. Cyclodehydration of butane-1,4-diol, pentane-1,5-diol and hexane-1,6-diol catalysed by H3PW12O40 gave tetrahydrofuran, tetrahydropyran and oxepane, respectively. Cyclodehydration of diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether and polyethylene glycol 200 catalysed by H3PW12O40 gave 1,4-dioxane. In particular, cyclodehydration of hexane-1,6-diol gave an excellent yield of oxepane (80%). The selectivity exhibited by the H3PW12O40 catalyst was even better than that exhibited by other reported catalyst systems for similar cyclodehydration reactions.

A Solution-Processed Heteropoly Acid Containing MoO3 Units as a Hole-Injection Material for Highly Stable Organic Light-Emitting Devices

We report hole-injection layers (HILs) comprising a heteropoly acid containing MoO3 units, phosphomolybdic acid (PMA), in organic light-emitting devices (OLEDs). PMA possesses outstanding properties, such as high solubility in organic solvents, very low surface roughness in the film state, high transparency in the visible region, and an appropriate work function (WF), that make it suitable for HILs. We also found that these properties were dependent on the postbaking atmosphere and temperature after film formation. When the PMA film was baked in N2, the Mo in the PMA was reduced to Mo(V), whereas baking in air had no influence on the Mo valence state. Consequently, different baking atmospheres yielded different WF values. OLEDs with PMA HILs were fabricated and evaluated. OLEDs with PMA baked under appropriate conditions exhibited comparably low driving voltages and higher driving stability compared with OLEDs employing conventional hole-injection materials (HIMs), poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate), and evaporated MoO3, which clearly shows the high suitability of PMA HILs for OLEDs. PMA is also a commercially available and very cheap material, leading to the widespread use of PMA as a standard HIM.