Catalytic behavior in CH4 decomposition of catalysts derived from red mud: Impact of residual Na2O

Catalyst samples for CH₄ decomposition were prepared from red mud (RM) by an acid-leaching neutralization precipitation approach. Water-washing the resultant precipitates multiple times, followed by drying at 105 °C and calcination at 500 °C, resulted in a threshold of residual Na₂O, equivalent to 96% Na₂O removal. Drying the precipitate at a higher temperature of 200 °C, followed by repeated water washing, provided a deeper Na₂O removal of 99% and made the resultant samples more active for the targeted reaction. Subsequently, four catalyst samples with a simulated red mud composition and NaOH contents from 0 to 0.3 wt% were prepared and the catalytic test results revealed that the Na₂O remaining in the RM-derived catalysts did not only inhibit their activation in CH₄ but also lower their maximal activities for CH₄ decomposition. Finally, two catalysts with the same simulated red mud composition and their Na impregnated respectively on Fe₂O₃ and a mixture support of Al₂O₃-SiO₂-TiO₂ were prepared and tested to explore the effect of Na distribution on the activation behavior of RM-derived catalysts for CH₄ decomposition. The activity testing results showed that it was the Na residual dispersed on iron oxides in the RM-derived samples to significantly inhibit the activation of CH₄ decomposition.     

Eco-friendly and degradable red phosphorus nanoparticles for rapid microbial sterilization under visible light

Pathogens pose a serious challenge to environmental sanitation and a threat to public health.The frequent use of chemicals for sterilization in recent years has not only caused secondary damage to the environment but also increased pathogen resistance to drugs,which further threatens public health.To address this issue,the use of non-chemical antibacterial means has become a new trend for environmental disinfection.In this study,we developed red phosphorus nanoparticles(RPNPs),a safe and degradable photosensitive material with good photocatalytic and photothermal properties.The red phosphorus nanoparticles were prepared using a template method and ultrasonication.Under the irradiation of simulated sunlight for 20 min,the RPNPs exhibited an efficiency of 99.98%in killing Staphylococcus aureus due to their excellent photocatalytic and photothermal abilities.Transmission electron microscopy and ultraviolet–visible spectroscopy revealed that the RPNPs exhibited degradability within eight weeks.Both the RPNPs and their degradation products were nontoxic to fibroblast cells.Therefore,such RPNPs are expected to be used as a new type of low-cost,efficient,degradable,biocompatible,and eco-friendly photosensitive material for environmental disinfection.     

Tuning of emission by effect of local symmetry in BaLaLiWO6:Dy3+/Eu3+ for WLEDs

The luminescence center energy transfer, crystal field strength, and covalency are limited by the crystal structure of the host and subsequently affect the luminescence efficiency, color, and intensity. Here, we report an excellent red phosphor BaLaLiWO₆:0.40Eu³⁺ and the dependence between symmetry and luminous performance. A model for changing symmetry is drawn by analyzing the Coulomb potential and structure for the application of a double-perovskite phosphor BLLWO: Dy³⁺, Eu³⁺ in white light LEDs. The addition of Dy³⁺/Eu³⁺ makes the W-O bond formed by the B-site and oxygen ion longer and the Li-O bond shorter, and the difference between the eight octahedral around the A-site is reduced, increasing the symmetry of the A-site. Local symmetry was successfully modulated by changing the Eu³⁺ concentration to control the Y/B ratio of Dy³⁺ and the R/O ratio of Eu³⁺ and smoothly achieved (0.382, 0.373) warm white light color coordinate. The phosphor has excellent thermal stability and still has 92.3% intensity at 475 K. The above results show that the wavelength composition of the luminescence is tunable by changing the symmetry of the environment in which the doped ions are located. It applies to single hosts for the regulation of white light emission.     

植物基人造肉的营养特性与食用安全性

植物肉的出现为动物肉类食品供应短缺和养殖业环境污染问题带来希望。食品加工技术的快速发展弥补了植物基肉制品外观和口感的不足, 但其营养价值和安全性也应引起重视。本文综述了以植物蛋白为主要原料所制肉类替代品的营养价值, 包括植物肉中碳水化合物、蛋白质、脂肪、水分、维生素和矿物质的相对含量和营养性质。分析了植物肉在生产及食用过程中可能出现的物理、化学、生物因素在内的安全问题, 并探讨目前植物肉发展所存在的局限性与挑战, 以期为我国植物蛋白肉制品的研发与推广提供理论参考。     

基于蛋白质组学技术研究秦川牛肉宰后贮藏过程中肌红蛋白含量及其衍生物转化

本实验采用4D-非标记蛋白质组学技术研究秦川牛肉贮藏过程中（0～8 d）肌红蛋白含量及其衍生物的转化情况，阐释冷却秦川牛肉中肌红蛋白含量及其衍生物转化的分子机制。结果表明：贮藏过程中，肌红蛋白表达量在宰后0～4 d上升、4～8 d下降，利用非标记蛋白质组学技术鉴定出与肌红蛋白及其衍生物相关的差异蛋白14 种，具体包括代谢酶、氧化还原酶、过氧化物酶、伴侣蛋白4 类，这4 类蛋白的表达共同调控贮藏过程中肌红蛋白含量的变化及其3 种衍生物之间的转化，具体表现为贮藏过程中肌红蛋白表达量整体呈下降趋势，氧合肌红蛋白相对含量持续下降，脱氧肌红蛋白、高铁肌红蛋白相对含量逐渐增加，导致肉色发生褐变。本研究结果有利于理解秦川牛肉贮藏过程肉类变色的复杂生化变化机制。     

Why do small business butcher shops fail to fully implement HACCP?

This study aims to assess the degree of HACCP implementation in small business butcher shops and understand which factors most influence butchers' intention to fully implement it, through the application of the Theory of Planned Behaviour. One hundred and one butchers managing or owning small butcher's responded to the interview regarding their Attitudes, Subjective Norm, Perceived Behavioural Control, Personal Norm, and Knowledge with regard to their Intention to fully implement a HACCP system in their shops. Before the interviews, a certified veterinarian visited all the shops. Visits included an inspection of the establishments using the Official Portuguese Control Plan checklist for meat retailers. Conformance level measured past performance regarding food safety practices. Based on past performance, butchers were divided into “high performers” and “low performers”. “High performers” yielded high values of Attitude and Intention towards the Behaviour. For these, Attitude and Personal Norm emerge as predictors of the Intention to fully implement a HACCP system. For “low performers”, Personal Norm was the strongest predictor of Intention, with results pointing to the need for an intervention from the authorities to promote increased conformance to food safety practices. For both groups, neither Social Norm nor Perceived Behavioural Control acted as significant predictors of Intention.     

Extended preservation of raw beef and pork meat by hyperbaric storage at room temperature

Hyperbaric storage (HS) was evaluated as a new food preservation methodology at room temperature (RT) for beef and pork meat, both minced and in pieces, and compared to refrigeration (RF) storage. The meat samples were stored at 50, 75 and 100 MPa and variable RT up to 60 days. HS at 75 and 100 MPa could not only inhibit microbial growth but also inactivate microorganisms. Regarding physicochemical analyses, an overall equal to better pH maintenance in HS samples was achieved, and similar colour differences between HS and RF were observed. Generally, similarities in moisture content and drip loss between HS (mostly 75 and 100 MPa) and RF were detected (tendency for lower values in the former and higher values in the latter for the higher pressure level). Protein solubility revealed a decrease of sarcoplasmic protein values during storage with a pressure level dependency in some samples.     

Effect of marinating ingredients on temperature-induced denaturation of hemoglobin and its relation to red blood spot formation in cooked chicken breast

Red blood spot (RBS) commonly found in cooked chicken breast has caused severe economic loss as it is perceived as a sign of undercooked product. The objectives of this study were to investigate the cause of RBS as related to common ingredients used in marination, based on both chicken breast and isolated chicken hemoglobin (Hb) models. The effect of sodium chloride (NaCl), sodium tripolyphosphate (STPP), and glucose on thermal denaturation of Hb was investigated along with the extent of RBS formation in cooked marinated chicken breast. After vacuum tumbling for 65 min and subsequent storage at 4 °C for 20 hr, STPP and glucose were not absorbed into the center of chicken breast. However, Na⁺ was absorbed after 12 hr storage. The denaturation temperature (T_d) of isolated chicken Hb decreased to 65.8 °C in the presence of 1.5 M NaCl, while that of the control was 69.4 °C. STPP at pH 9 decreased T_d of Hb to 61.4 °C. The alkaline pH induced by STPP destabilized the Hb structure. RBSs were observed at 100% incidence when cooked to core temperatures of 50 and 70 °C for 1 min. RBSs were completely eliminated at core temperature of 85 °C. The ingredients used during marination appeared to have a minimal effect on RBS formation due to their limited absorption into the chicken breast. The cooking temperature is a major factor governing RBSs, as it directly affects the denaturation of Hb.