Highly Active CuO/KCC−1 Catalysts for Low-Temperature CO Oxidation

Copper catalysts have been extensively studied for CO oxidation at low temperatures. Previous findings on the stability of such catalysts, on the other hand, revealed that they deactivated badly under extreme circumstances. Therefore, in this work, a series of KCC−1-supported copper oxide catalysts were successfully prepared by impregnation method, of which 5% CuO/KCC−1 exhibited the best activity: CO could be completely converted at 120 °C. The 5% CuO/KCC−1 catalyst exhibited better thermal stability, which is mainly attributed to the large specific surface area of KCC−1 that facilitates the high dispersion of CuO species, and because the dendritic layered walls can lengthen the movement distances from particle-to-particle, thus helping to slow down the tendency of active components to sinter. In addition, the 5% CuO/KCC−1 has abundant mesoporous and surface active oxygen species, which are beneficial to the mass transfer and promote the adsorption of CO and the decomposition of Cu+–CO species, thus improving the CO oxidation performance of the catalyst.

Age features of morphological changes of the hematotesticular barrier in experimental diabetes mellitus.

Background. Diabetes mellitus is an acute medical and social problem in all parts of the world due to the constant increase in the incidence of the disease, severe complications, disability and high mortality. Hyperglycemia leads to oxidative stress and increased processes of formation of active oxygen species, which in turn make a significant contribution to the development of male infertility. Objective. Therefore, the aim of our study was to establish morphological changes in the vessels of the hemomicrocirculatory flow and testicular sustentocytes of adult rats with experimental streptozotocin diabetes mellitus (SDM). Methods. The material for the study were the testicles of 20 sexually mature 6-month-old rats (weighing 150-180 g). SDM in animals of the experimental group was simulated by a single intraperitoneal injection of streptozotocin (dissolved in 0.1 M citrate buffer solution with a pH of 4.5) at a dose of 6 mg per 100 g of mass. An equivalent dose of 0.1 M citrate buffer was injected intraperitoneally to animals of the control group. Histological, electron microscopic, biochemical, morphometric and statistical research methods were used. Results. It was found that in the early stages of SDM (28th day) on the background of hyperglycemia in the hemomicrocirculatory flow of the testes there is a spasm of the vessels of the afferent link, which is confirmed by a decrease in the lumen of arterioles and an increase in their Wagenworth index. On the 70th day of SDM on the background of elevated levels of glucose and glycosylated hemoglobin in the links of the hemomicrocirculatory flow of the testis there are signs of diabetic microangiopathy, manifested by: hemorheological disorders in micro-hemo-vessels, (erythrocyte sludge, adhesion of erythrocytes and platelets, microclasmatosis), decrease in the capacity of arterioles and capillaries (increase in the Wagenworth index, respectively by 1.8 and 1.9 times), microclasmatosis, thickening and proliferation of the basement membrane of capillaries. Against the background of diabetic microangiopathy, there is a decrease in the number of sustentocytes by 0.01 mm2 of testicular parenchyma by 1.8 times, compared with control indicators, the area of their profile increases by 2.2 times (in all cases p<0.05). The nucleolar areas probably do not change, which leads to an increase in the nuclear-cytoplasmic ratio by 2.9 times (p<0.05). Such morphometric changes of sustentocytes are caused by development of vacuolar hydropic dystrophies in them, and an apoptosis that is confirmed by data of histo-ultrastructural studies. Changes in sustentocytes against the background of the development of diabetic microangiopathy lead to a violation of the hematotesticular barrier and to dystrophic changes in the spermatogenic epithelium of the testis. Conclusion. Thus, on the 70th day of SDM in the hemomicrocirculatory flow of the testis, the development of diabetic microangiopathy is observed, which leads to a violation of the hematotesticular barrier, and as a consequence, to a violation of spermatogenesis.

Variations in Plant Growth Characteristics due to Oxygen Plasma Irradiation on Leaf and Seed

Gene expression variations of plant leaf are investigated by irradiating seed and leaf with oxygen or air plasmas. Enhancement of leaf growth is induced by oxygen plasma irradiation on seeds, which is supported by increased gene expression for protein synthesis, oxidative-reduction reactions and decreased gene expression concerning DNA methylation and histone modification. Suppression of leaf growth is observed by the oxygen plasma, which would be owing to increased gene expression concerning heat shock protein and redox reaction, and decreased expression of photosynthesis and glycoprotein. Also, gene expression variation due to air plasma irradiation is almost same as that of oxygen plasma. Active oxygen species are major factors in both oxygen and air plasmas for the variation of gene expressions in plant.

Efficient reduction of methylene blue in aqueous solution using a Fenton-like catalyst of Fe3O4/Cu

This work aimed to investigate the efficient reduction of methylene blue (MB) by a heterogeneous magnetic nanoparticles/copper (MNs/Cu) Fenton-like catalyst. The MNs/Cu was successfully synthesized in the presence of Citrus aurantifolia extract. The characterizations showed an effective fabrication of Cu onto the surface of MNs. The reduction of MB by the MNs/Cu Fenton-like catalyst presented an efficiency of 99.5% at the optimum conditions, including MNs/Cu dose of 0.1 mg, temperature of 25°C, contact time of 75 min, pH 4.0, and 20 mL H2O2 30%, MB initial concentration of 25 mg/L. The reduction kinetics was well fitted to pseudo-second-order with reaction rate constant of 0.0029 g/mg.min. The main mechanism of the MB reduction due to active oxygen species was pointed out. The decrease of reduction yield at high pH, catalyst dose and MB concentration was elucidated in this study.

The Influence of Precursor on the Preparation of CeO2 Catalysts for the Total Oxidation of the Volatile Organic Compound Propane

CeO2 catalysts were prepared by a precipitation method using either (NH4)2Ce(NO3)6 or Ce(NO3)3, as CeIV or CeIII precursors respectively. The influence of the different precursors on catalytic activity was evaluated for the total oxidation of propane with water present in the feed. The catalyst prepared using the CeIV precursor was more active for propane total oxidation. The choice of precursor influenced catalyst properties such as surface area, reducibility, morphology, and active oxygen species. The predominant factor associated with the catalytic activity was related to the formation of either CeO2.nH2O or Ce2(OH)2(CO3)2.H2O precipitate species, formed prior to calcination. The formation of CeO2.nH2O resulted in enhanced surface area which was an important factor for controlling catalyst activity.

Molecular Interactions between Methylene Blue and Sodium Alginate Studied by Molecular Orbital Calculations

A methylene blue (MB) indicator embedded in sodium alginate (SA) film was previously examined for detecting active oxygen species. In a previous study, spectrometry was used to identify and characterize the MB/SA complex. However, the decolorization mechanism was not fully assessed. In this study, our aim is to conduct computational calculations at the B3LYP/6-31G(d) level to clarify the exact types and positions of the interaction that cause the decolorization in MB. The results demonstrate that MB/SA interacts with carboxylates (-COO(superscript)-(superscript)) of SA and the N, C, and S atoms of MB, confirming previous experimental observations.

A Literature Review on High-Performance Photocatalysts for Sustainable Cancer Therapy

Since cancer is a serious threat to public health worldwide, the development of novel methods and materials for treating cancer rapidly and thoroughly is of great significance. This review summarizes the mechanism and application of photocatalytic materials used to kill cancer cells. The photosensitivity and toxicological properties of several common photcatalysts used in anti-cancer treatment are discussed in detail. The ideal photocatalyst must possess the following characteristics: a highly stable production of active oxygen species and high selectivity to cancer cells without causing any damage to healthy tissues. This work concluded the existing photocatalytic materials used to treat cancer, as well as the current challenges in the application of cancer therapy. We aim to provide a basis for the development of new photocatalytic anti-cancer materials with high stability and selectivity while maintaining high photodynamic reaction performance.

Fine cubic Cu2O nanocrystals as highly selective catalyst for propylene epoxidation with molecular oxygen

Propylene epoxidation with O2 to propylene oxide is a very valuable reaction but remains as a long-standing challenge due to unavailable efficient catalysts with high selectivity. Herein, we successfully explore 27 nm-sized cubic Cu2O nanocrystals enclosed with {100} faces and {110} edges as a highly selective catalyst for propylene epoxidation with O2, which acquires propylene oxide selectivity of more than 80% at 90–110 °C. Propylene epoxidation with weakly-adsorbed O2 species at the {110} edge sites exhibits a low barrier and is the dominant reaction occurring at low reaction temperatures, leading to the high propylene oxide selectivity. Such a weakly-adsorbed O2 species is not stable at high reaction temperatures, and the surface lattice oxygen species becomes the active oxygen species to participate in propylene epoxidation to propylene oxide and propylene partial oxidation to acrolein at the {110} edge sites and propylene combustion to CO2 at the {100} face sites, which all exhibit high barriers and result in decreased propylene oxide selectivity.