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2.
Radicals generated in plastic medical devices (solid phase) by γ-rays or electron-beam irradiation during sterilization are known to cause oxidation of protein drugs, resulting in a loss or reduction in drug efficacy. The generation of radical species in water by the radical species in solid polymers has not been proved. Using electron spin resonance (ESR) spectroscopy, we confirm the generation of new radicals in water by γ-ray irradiated cyclic olefin polymers (COP). ESR measurements are obtained using 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) as a spin probe and 5-(2,2-dimethyl-1,3-propoxycyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO) as a spin trap, in which the irradiated COP was immersed. The ESR signals indicate the TEMPOL radicals decline over time, suggesting the generation of new radicals. Conversely, the characteristic ESR signals of the adduct formed by the reaction between CYPMPO and the hydroxyl radical are observed. Thus, hydroxyl radicals are generated because of the migration of the radicals from COP to water. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48604. 相似文献
3.
《International Journal of Hydrogen Energy》2020,45(53):28792-28799
The most ideal substitute for Pt/C to catalyze the oxygen reduction reaction (ORR) is the transition metal and nitrogen co-doped carbon-based material (TM-N-C). However, large particles with low catalytic activity are formed easily for the transition metals during high-temperature carbonization. Herein, PAN nanofibers uniformly distributed with FeCl3 were coated with SiO2 and then carbonized to obtain Fe–N–Si tri-doped carbon nanofibers catalyst (Fe–N–Si-CNFs). The SiO2 can further anchor the Fe atoms, thus preventing agglomeration during the carbonization process. Meanwhile, Si atoms have been doped in CNFs during this process, which is conducive to the further improvement of catalytic performance. The Fe–N–Si-CNFs catalyst has a 3D network structure and a large specific surface area (809.3 m2 g−1), which contributes to catalyzing the ORR. In alkaline media, Fe–N–Si-CNFs exhibits superior catalytic performance (E1/2 = 0.86 V vs. RHE) and higher stability (9.6% activity attenuation after 20000s) than Pt/C catalyst (20 wt%). 相似文献
4.
Responsible innovation (RI) offers a promising step towards a more responsible adoption of innovations, such as new and emerging technologies. However, how RI would be practised in different cultural contexts and settings is still less studied, especially in the context of developing countries. Taking the utilisation of CO2 in Indonesia as an empirical case, the purpose of this paper is to explore this issue through examining the influence of key characteristics of Indonesia's national culture on core dimensions of RI: anticipation, reflexivity, deliberation, responsiveness and participation. The different RI dimensions are applied in practice in a focus group discussion (FGD) and a round of interviews with different stakeholders that explored CO2 utilisation in the country. Hofstede's classification of national cultural dimensions is used to single out key focus points for attention in these RI processes in the Indonesian context. The results from the experiment illustrate that culture matters in the application of RI dimensions in practice. In the sense that in order for RI to work well, the governance of core RI processes such as participation and deliberation has to be adjusted to social norms of what is considered legitimate, desirable and good behaviour. These norms differ across societies. The findings further suggest ways of applying RI dimensions in practice. 相似文献
5.
《Ceramics International》2015,41(6):7796-7802
The perovskite proton conductors BaxCe0.7Zr0.1Y0.1Yb0.1O3−δ (x=0.9, 0.94, 0.98, 1.0, 1.03, 1.06, and 1.1) have been successfully prepared by the conventional solid state reaction route. X-ray diffraction (XRD) patterns of the samples indicate that BaxCe0.7Zr0.1Y0.1Yb0.1O3−δ (x≥1.0) samples possess a single phase orthorhombic structure, but a secondary phase (Y,Ce)O2−δ exists in BaxCe0.7Zr0.1Y0.1Yb0.1O3−δ (x<1.0) samples. SEM photographs show that the grain size of BaxCe0.7Zr0.1Y0.1Yb0.1O3−δ increases and the porosity decreases with Ba2+ content varying from x=0.9 to 1.1. Because of ZnO addition as sintering aid, the sintering temperature of the samples reduces from 1550 °C to 1250 °C. The chemical stability of the samples against CO2 decreases with the increase in Ba content from x=0.9 to 1.1. All the samples show a excellent stability against water vapor at 850 °C. The conductivities of the samples increase and the activation energies reduce with the increase in Ba content. The present results suggest that it is very important to control the stoichiometry of cations to obtain desired perovskite type high temperature proton conductors. 相似文献
6.
Diego Rocha-Parra Luciana León Bianchi Fernando Gentico David Garcia-Burgos María C. Zamora 《International Journal of Food Science & Technology》2021,56(8):3876-3884
The aim of the present study was to compare the information provided by a discrete and continuous data analysis of two emotions (disgust and joy), elicited by bitter-tasting beverages (coffee, yerba mate infusion and grapefruit juice) in two groups with different body mass index (BMI): overweight group (25 < BMI < 30), and healthy-weight control group (18.5 < BMI ≤ 25). Participants (n = 66; 34 females, 32 males) evaluated a total of three consecutive sips of the same beverage (taking one sip every 20 s and registering a continuous video for 60 s). The Wilcoxon test (continuous analysis) showed some changes generated as the drinks were being consumed. The biggest difference was the expression of disgust for coffee in the high BMI group, at the first sip (0–10 s). It represented 27% compared to 2% in normal BMI. The continuous analysis allowed to observe the periods where the differences were greater (0–10 and 40–50 s). 相似文献
7.
Daniel R. Parrish Ronald B. Pegg William L. Kerr Ruthann B. Swanson Guangwei Huang Adrian L. Kerrihard 《International Journal of Food Science & Technology》2019,54(6):2190-2198
Further investigations of almond degradation under typical industrial storage conditions from a quantitative perspective are warranted. This study modeled effects of packaging, temperature (TEMP), relative humidity (RH) and roasting on chemical attributes of almonds stored according to common industry practices throughout 16 months. Roasted samples were stored in high-barrier bags (HBB) or polypropylene bags (PPB) at multiple combinations of TEMP and RH. Raw samples were held in unlined cardboard cartons (UC) or PPB under the same conditions. Almonds were assessed bimonthly for oxidation products, free fatty acids, moisture content and water activity. Results indicated roasting almonds improved quality preservation. Models showed HBB (rather than PPB) to provide benefits to stability comparable to reductions in storage TEMP of ~15 to 30 °C. PPB (rather than UC) showed benefits to peroxide formation of similar magnitude. Our data shows HBB to be a superior packaging choice, and UC to associate with the greatest rates of degradation. 相似文献
8.
After centuries of cultural and economic conquest of the Americas by European and Euro-American conquistadors, contemporary rhetoric in ex-colonial powers heralds the decline of material and ideological imperialism. Instead, it is purported that today's world is peopled by a great brotherhood, with the more affluent striving to relieve their less fortunate, underdeveloped kith. This conviction is inherent in organizations which dispense money, information, training, and other resources in the name of community development and endangered species and environmental conservation. What is rarely perceived – and practically never said – is that these “benevolent” foreign aid activities typically result in the concentration of resources and power in the hands of a few, the building of empires, and the compounding of already difficult situations, counter-productive to stated objectives. The Yucatán Peninsula is a classic case of persistent imperialism: the geographic name is a corruption of the Mayan “matan cub a than” (“I do not understand you”), while contemporary development and conservation programs habitually exhibit cultural ignorance and dominance. This paper explores a diverse literature on non-governmental organizations, reflects on likely consequences of cultural dominance, and implores professional anthropologists to be adventurous in propagating anthropological knowledge relevant to environmental protection. 相似文献
9.
Polychaetous annelid assays were performed with laboratory inbred cultures of juvenile and adult Neanthes arenaceodentata and Capitella capitata to cadmium, chromium, copper, lead, mercury, and zinc in sea water. Data were presented as 96-h and 28-day LC50 concentrations. Mercury and copper were the two most toxic with zinc and chromium generally the next most toxic followed by lead and cadmium. The adult stages of both species were more tolerant to these metals than the juveniles. Comparisons of these six metals present in the two large domestic sewage outfalls in Los Angeles County indicate that the amount of copper and zinc present in the effluent exceeds the 28-day LC50 of these two polychaetes. The results were compared to the water quality standards for discharges in the State of California. 相似文献
10.
《Journal of the European Ceramic Society》2022,42(10):4320-4327
Yb doped (0, 0.02, 0.1 and 0.5 at%) MgO transparent ceramics were synthesized through spark plasma sintering (SPS) at the relatively low temperature of 1100 °C for 5–60 min under a pressure of 105 MPa. The effects of dopant concentration and sintering holding time on the densification and microstructure evolution of MgO ceramics were investigated. All ceramics reached a relative density greater than 99.20%. The 0.02% Yb-doped MgO ceramic sintered at 1100 °C for 60 min showed the highest in-line transmittance, of 80% at 1030 nm, a value close to that of MgO single crystals. Yb dopant improved the transmittance, degree of densification and control of grain growth. Herein, the influence of Yb doping on the crystalline phase and microstructure was explored, and the photoluminescence properties of Yb in transparent MgO ceramics were investigated. 相似文献