Antioxidant/prooxidant properties of model phenolic compounds: Part I. Studies on equimolar mixtures by chemiluminescence and cyclic voltammetry

The electrochemical behaviour and the antioxidant effectiveness of ascorbic acid (AA), caffeic acid (CA), quercetin (Q), catechin (Cat), hesperetin (H) and their equimolar binary mixtures were evaluated by means of cyclic voltammetry and luminol Co(II)–EDTA chemiluminescence, respectively, with a view to the prediction of a potential prooxidant or synergistic behaviour of mixtures of antioxidants. An important synergistic oxidation between Q and Cat was observed. The mixture CA/AA manifested the most prooxidant tendency among all the tested compounds and their mixtures. AA increased the antioxidant activity of Q and decreased that of Cat. Q and Cat regenerated CA, the prooxidant effect of the mixtures increasing with less e-delocalisation. Cat and CA have an antagonistic effect. H has the closest oxidation potential to CA and a slight increase of its antioxidant activity was registered when mixed with CA, which was not the case when it was combined with the other compounds or measured alone.     

Telocytes’ Role in Modulating Gut Motility Function and Development: Medical Hypotheses and Literature Review

This review article explores the telocytes’ roles in inflammatory bowel diseases (IBD), presenting the mechanisms and hypotheses related to epithelial regeneration, progressive fibrosis, and dysmotility as a consequence of TCs’ reduced or absent number. Based on the presented mechanisms and hypotheses, we aim to provide a functional model to illustrate TCs’ possible roles in the normal and pathological functioning of the digestive tract. TCs are influenced by the compression of nearby blood vessels and the degree of fibrosis of the surrounding tissues and mediate these processes in response. The changes in intestinal tube vascularization induced by the movement of the food bowl, and the consequent pH changes that show an anisotropy in the thickness of the intestinal tube wall, have led to the identification of a pattern of intestinal tube development based on telocytes’ ability to communicate and modulate surrounding cell functions. In the construction of the theoretical model, given the predictable occurrence of colic in the infant, the two-layer arrangement of the nerve plexuses associated with the intestinal tube was considered to be incompletely adapted to the motility required with a diversified diet. There is resulting evidence of possible therapeutic targets for diseases associated with changes in local nerve tissue development.     

库底淤砂对地震动水压力的影响

假定淤砂为多孔弹性介质,探讨其对地震动水压力的影响。结果表明,对于饱和淤砂,动水压力波的吸收主要来自于基础,但淤砂层含有少量气体时,淤砂层对动水压力影响较大。     

土坝与基础动力相互作用的简化分析

 本文采用地震随机模型，来分析坝与基础的相互作用问题，得出了一些规律，这比计算一条或几条地震波输入而求出的坝体动力反应更具有代表性。     

Understanding social collaboration between actors and technology in an automated and digitised deep mining environment

The purpose of this article is to develop knowledge and learning on the best way to automate organisational activities in deep mines that could lead to the creation of harmony between the human, technical and the social system, towards increased productivity. The findings showed that though the introduction of high-level technological tools in the work environment disrupted the social relations developed over time amongst the employees in most situations, the technological tools themselves became substitute social collaborative partners to the employees. It is concluded that, in developing a digitised mining production system, knowledge of the social collaboration between the humans (miners) and the technology they use for their work must be developed. By implication, knowledge of the human's subject-oriented and object-oriented activities should be considered as an important integral resource for developing a better technological, organisational and human interactive subsystem when designing the intelligent automation and digitisation systems for deep mines. STATEMENT OF RELEVANCE: This study focused on understanding the social collaboration between humans and the technologies they use to work in underground mines. The learning provides an added knowledge in designing technologies and work organisations that could better enhance the human-technology interactive and collaborative system in the automation and digitisation of underground mines.     

One‐pot curing system of epoxy resin imines initiated with water

The curing and adhesive properties of one‐component epoxy resins containing Epikote 828 and diimines, derived from N,N′‐di(1‐ethylpropylidene)‐m‐xylylenediamine, N,N′‐di(1‐ethylpropylidene)‐1,3‐diaminomethylcyclohexane (2), and N,N′‐di(1,3‐dimethylbutylidene)‐m‐xylylenediamine, which were used as water‐initiated hardeners, were examined. Diethyl ketone‐based imines with a lower electron density on the C?N carbon were efficiently hydrolyzed and showed curing activity. 2, a novel diethyl ketone‐based diimine, served as an efficient latent hardener of the epoxy resin. A paste of the epoxy resin with 2 showed good storage stability at room temperature and good adhesive properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 878–882, 2003     

Diethyl ketone‐based imine as efficient latent hardener for epoxy resin

Several imines were synthesized and evaluated as water‐initiated hardener for epoxy resin. Imines with a lower electron density on the C=N carbon showed a faster hydrolysis rate. Diethyl ketone‐based imines were the most efficiently hydrolyzed among the imines examined, and the adhesive properties of epoxy resin with diimines used as the hardeners were evaluated. A novel diethyl ketone‐based diimine, N,N′‐di(1‐ethylpropylidene)‐m‐xylylenediamine (10), served as an efficient latent hardener of epoxy resin. Epikote 828 containing 10, filler, and dryer increased the adhesive strength faster than Epikote 828 containing filler and dryer with methyl isobutyl ketone‐based imine. The mixed system of epoxy resin and 10 showed good storage stability at room temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1744–1749, 2002     

Daphne oleoides: An alternative source of important sesquiterpenes

This study was targeted to characterize the chemical composition and antibacterial properties of Daphne oleoides subsp. oleoides essential oil. The essential oil was analyzed and quantified by gas chromatography and gas chromatography/mass spectrometry. Additionally, the broth dilution method was used to evaluate its antibacterial activity against Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Streptococcus faecalis (ATTC 29212), Escherichia coli (ATCC 25922), Proteus mirabilis (ATCC 25933), Proteus vulgaris (ATCC 13315), Pseudomonas aeruginosa (ATCC 27853), and Salmonella typhi Ty2 (ATCC 19430). Seventy-nine compounds were identified, representing 95.2% of the total oil. Nootkatone (18.5%), nootkatin (12.1%), and daphnauranol C (11.7%) were determined as the main constituents in the oil. Oxygenated sesquiterpenes were dominating in the oil (43.0%), followed by fatty acid derivatives (13.7%) and carbonylic compounds (9.6%). The minimal inhibitory/bactericidal concentrations of essential oils of D. oleoides were in the range from 25–100 μg/mL, which can be considered as high activity in comparison with the reference antibiotic which was active in the rangefrom 3.12–100 μg/mL. The greatest minimal inhibitory concentration value was determined as 25 µg/mL against both two Bacillus strains and S. epidermidis, B. cereus, B. subtilis, and S. aureus were the most sensitive strains against essential oils when compared with the minimal inhibitory concentrations of control antibiotic. Consequently, Daphne oleoides subsp. oleoides can be exploited as a source of natural antibacterial agents and nootkatone for the pharmaceutical, food, and agricultural industries.