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971.
Chiara Piccini Giampiero Cai Maria Celeste Dias Mrcia Araújo Sara Parri Marco Romi Claudia Faleri Claudio Cantini 《International journal of molecular sciences》2021,22(20)
In recent decades, atmospheric pollution led to a progressive reduction of the ozone layer with a consequent increase in UV-B radiation. Despite the high adaptation of olive trees to the Mediterranean environment, the progressive increase of UV-B radiation is a risk factor for olive tree cultivation. It is therefore necessary to understand how high levels of UV-B radiation affect olive plants and to identify olive varieties which are better adapted. In this study we analyzed two Italian olive varieties subjected to chronic UV-B stress. We focused on the effects of UV-B radiation on RubisCO, in terms of quantity, enzymatic activity and isoform composition. In addition, we also analyzed changes in the activity of antioxidant enzymes (SOD, CAT, GPox) to get a comprehensive picture of the antioxidant system. We also evaluated the effects of UV-B on the enzyme sucrose synthase. The overall damage at biochemical level was also assessed by analyzing changes in Hsp70, a protein triggered under stress conditions. The results of this work indicate that the varieties (Giarraffa and Olivastra Seggianese) differ significantly in the use of specific antioxidant defense systems, as well as in the activity and isoform composition of RubisCO. Combined with a different use of sucrose synthase, the overall picture shows that Giarraffa optimized the use of GPox and opted for a targeted choice of RubisCO isoforms, in addition to managing the content of sucrose synthase, thereby saving energy during critical stress points. 相似文献
972.
Iaki Ucar Marco Gramaglia Marco Fiore Zbigniew Smoreda Esteban Moro 《Journal of the Royal Society Interface》2021,18(185)
Reliable and timely information on socio-economic status and divides is critical to social and economic research and policing. Novel data sources from mobile communication platforms have enabled new cost-effective approaches and models to investigate social disparity, but their lack of interpretability, accuracy or scale has limited their relevance to date. We investigate the divide in digital mobile service usage with a large dataset of 3.7 billion time-stamped and geo-referenced mobile traffic records in a major European country, and find profound geographical unevenness in mobile service usage—especially on news, e-mail, social media consumption and audio/video streaming. We relate such diversity with income, educational attainment and inequality, and reveal how low-income or low-education areas are more likely to engage in video streaming or social media and less in news consumption, information searching, e-mail or audio streaming. The digital usage gap is so large that we can accurately infer the socio-economic status of a small area or even its Gini coefficient only from aggregated data traffic. Our results make the case for an inexpensive, privacy-preserving, real-time and scalable way to understand the digital usage divide and, in turn, poverty, unemployment or economic growth in our societies through mobile phone data. 相似文献
973.
The effect of water on the morphology of four ethylene vinyl alcohol copolymers (EVOH) with different ethylene contents was studied by differential scanning calorimetry (DSC). EVOH film samples equilibrated in controlled atmospheres at different relative humidities (RH) and 23°C were analyzed. Under dry conditions, the glass transition temperature (Tg) was unaffected by copolymer ethylene content. As RH increases, Tg decreases. It seems that the presence of water within the polymer matrix results in plasticization of the polymer. Tg varies from around 50°C (dry) to below room temperature. EVOH copolymers are glassy polymers when dry and rubbery polymers at high RHs. Fox and Gordon–Taylor's equations well describe Tg depletion at low water uptake, although severe water gain results in a considerable Tg decrease, which is not predicted by these theories. Melting temperature, Tm, and enthalpy, ΔHm, were also analyzed. When dry, Tm decreases as ethylene content increases. No significant water effect was found on either Tm or ΔHm. Hence, crystallinity seems to be unaffected by water presence. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1201–1206, 1999 相似文献
974.
975.
Through comparative studies on the controlled thermally initiated radical polymerization of styrene in the presence of N-oxyls, the effect of the type of the N-oxyls (2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (OH-TEMPO), 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl (oxo-TEMPO) and 4-acetamido-2,2,6,6-tetramethylpiperidine-N-oxyl (acetamido-TEMPO)), as well as the concentration of the N-oxyls (3–20 mmol L–1) are discussed. The radical formation proceeds exclusively through the thermal initiation of styrene, i.e. without using any initiator. It is observed, that the thermal self-initiation of styrene increases the radical yield remarkably with the N-oxyls concentration, independent of the type of the N-oxyl. The concentration-dependent side reactions of substituted N-oxyls are remarkably more pronounced than those of unsubstituted N-oxyl. This leads to the reduction of the overall rate of polymerization (vbr) as compared to TEMPO (vbr = vbr (thermal polymerization)) with respect to the concentration, but independent of the type of substituents. 相似文献
976.
977.
George Chatzipirpiridis Carmela de Marco Eva Pellicer Olgaç Ergeneman Jordi Sort Bradley J. Nelson Salvador Pané 《Advanced Engineering Materials》2018,20(9)
978.
Sven Bergmann Matthias Brenner Jennifer Susanne Strehse Tobias Hartwig Bünning Edmund Maser Philipp Grassel David Heuskin David Brandt Marco Berger Simon van der Wulp Mathew Skellhorn Polly Hill Sven Van Haelst Maarten De Rijcke Uwe Wichert 《Propellants, Explosives, Pyrotechnics》2024,49(4):e202300322
Shipwrecks and dumped munition continue to be a major hazard, both in the North Sea but also on a global scale. Research within the EU Interreg project North Sea Wrecks (NSW), in cooperation with the German Aerospace Centre, Institute for the Protection of Maritime Infrastructures (DLR), is generating new insights into the status of wrecks, the potential leakage of pollutants from remaining munitions loads and the effects of contamination on exposed marine organisms in the North Sea environment. Further, historical documents are generated from archives to describe ship's history and sinking scenario. These historical findings were compared to models and images of the visual inspections of the wrecks. Further, samples of water, sediment and organisms are being analysed for traces of explosives. Combining the results of these different fields of research allows for a better understanding of the environmental risks deriving from these wrecks. This process is shown below by focusing on the wreck of the German light cruiser SMS MAINZ, which sank in 1914. Data were compared to three additional wrecks situated also within the southern German Bight. Available data about the wrecks were preliminary assessed using a wreck risk model. Finally, wrecks were ranked according to their potential environmental risk. 相似文献
979.
In this article we present two contributions to the study of coaxial waveguide structures. First, we present an efficient and accurate technique to evaluate the modes in the coaxial waveguides; second, we analyze junctions involving coaxial and circular waveguides using the multimode equivalent network representation. Numerical and experimental results are presented, showing good agreement. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7: 180–194, 1997. 相似文献
980.
Marianela Hazel Álvarez-Hernández Francisco Artés-Hernández Felipe Ávalos-Belmontes Marco Antonio Castillo-Campohermoso Juan Carlos Contreras-Esquivel Janeth Margarita Ventura-Sobrevilla Ginés Benito Martínez-Hernández 《Food and Bioprocess Technology》2018,11(3):511-525
Fruit and vegetables are much appreciated by consumers due to their nutritional values and health-promoting compounds. However, different factors affect the postharvest life of such products, in where ethylene is a major one, even at low concentrations, besides temperature and relative humidity. Therefore, high attention has been focused on the development of effective tools to remove ethylene from the atmosphere surrounding these products during storage or in transit. Potassium permanganate scrubbers are one of the most used technologies to remove ethylene from horticultural products. To facilitate and improve the oxidation process, potassium permanganate has been supported onto inert solid materials of a small particle size. In this review, we aim to provide an outline of the most common materials used as potassium permanganate supports on postharvest treatment and their respective effects on quality aspects of various fresh produce during postharvest life. Vermiculite, activated alumina, zeolite, silica gel, activated carbon and clays are the most popular materials that have been used as a support of potassium permanganate-based ethylene scrubbers. The literature suggests that potassium permanganate supported onto silica gel or zeolite seems to be a promising tool to maintain fruit and vegetables quality attributes for long-term storage. Although vermiculite and activated alumina are the most commonly used materials to reach this goal, not promising results have been reported. 相似文献