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Your search keyword '"A. Stepniak"' showing total 106 results
Start Over Author "A. Stepniak" Publisher elsevier b.v.
106 results on '"A. Stepniak"'

36. Emerging alternative for artificial ammonia synthesis through catalytic nitrate reduction.

Author

Hao, Derek, Chen, Zhi-gang, Figiela, Monika, Stepniak, Izabela, Wei, Wei, and Ni, Bing-Jie

Subjects
DENITRIFICATION, CATALYTIC reduction, AMMONIA, HABER-Bosch process, CARBON emissions, NITRITES, WATER pollution
Abstract

Nitrate is having a much higher potential than N 2 for catalytic NH 3 synthesis under ambient conditions. [Display omitted] • The differences between N 2 and NO 3 − for NH 3 synthesis are systematically analyzed. • Recent advances in photo/electrochemical NO 3 − reduction to NH 3 are summarized. • Possible strategies to improve the selectivity and catalytic activity are proposed. Artificial catalytic synthesis of ammonia has become a hot research frontier in recent years. It is regarded as a promising approach that may replace the Haber-Bosch process and reduce global carbon dioxide emission. However, it is extremely difficult for the cleavage of nitrogen molecules under ambient conditions. Thus the ammonia yield rate is still low and the study is still limited in lab scale. If nitrites or nitrates are used as nitrogen sources, rather than nitrogen gas, the catalytic efficiency can be significantly improved, and the residual nitrate and nitrite contaminations in water systems can be efficiently eliminated and converted to energy sources at the same time. It is an emerging alternative for artificial ammonia synthesis, while there is not enough focus on the reduction of nitrate and nitrite. Herein, we systematically compared the differences between the reduction of nitrogen and nitrates, as well as listed the challenges in this area. The total conversion rate and energy efficiency of catalytic nitrate reduction are much higher than nitrogen gas reduction due to the much higher solubility and better converting pathway, which might be further enhanced by employing catalysts improvement strategies. Further, we also proposed suitable materials as well as a few future researches needs that may help boost the development of artificial ammonia synthesis using nitrate. [ABSTRACT FROM AUTHOR]

Published
2021
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42. Anti-inflammatory and antioxidative effects of the buds from different species of Populus in human gingival fibroblast cells: Role of bioflavanones.

Author

Pobłocka-Olech, Loretta, Inkielewicz-Stepniak, Iwona, and Krauze-Baranowska, Mirosława

Abstract

Background: Poplar leaf-buds (Populi gemmae) are used traditionally as anti-inflammatory agents to the treatment of skin injuries or cough. They differ in their diverse chemical composition and different types of activities, whose mechanisms are not fully recognized.Purpose: Evaluation and comparison of anti-inflammatory activity of leaf-buds extracts from Populus nigra, P. × berolinensis and P. lasiocarpa and flavanones - pinocembrin and pinostrobin towards human gingival fibroblasts (HGF-1) pro-inflammatory stimulated by silver nanoparticles (AgNPs). Determination of antioxidant activity associated with anti-inflammatory properties by means of bioautographic TLC tests.Methods: Phytochemical analysis was performed by TLC and videodensitometry analysis. The extracts were standardized on the pinocembrin and pinostrobin content. Bioautography was performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and riboflavin-light blue tetrazolium chloride (riboflavin-light-NBT) radicals to assess the extracts and both flavanones radical scavenging properties as well as potential inhibition of xanthine oxidase (XO) activity. The protective effects of poplar buds extract and flavanones - pinocembrin and pinostrobin on HGF-1 line exposured to AgNPs were investigated by analysis of interleukin 6 (IL-6) and interleukin IL-1β (IL-1β) level measured by ELISA kit. The messenger ribonucleic acid (mRNA) of both cytokines was determined by real-time quantitative PCR. The involvement of cyclooxygenase 2 protein (COX-2) was studied using Western blot analysis.Results: The presence of several flavanones and phenolic acids, which have radical scavenging properties, was revealed in all of the bud poplar extracts analyzed. Treatment with particular flavanones or extracts from buds of P. × berolinensis and P. nigra decreased the IL-6 and IL-1β release in HGF-1 cells and down-regulation of mRNA for both cytokines was observed. The COX-2 protein expression was demonstrated for pinocembrin and P. × berolinensis buds. These effects were not observed for buds from P. lasiocarpa not containing of flavonoids.Conclusion: The potential protective role of pinocembrin and pinostrobin and extracts from buds P. nigra and P. × berolinensis against AgNPs induced inflammation and cytotoxicity in HGF-1 cells is disclosed. In addition, the antioxidant properties of poplar bud extracts have been demonstrated. P. × berolinensis buds showed the highest activity in both the in vitro model and in the bioautographic tests. [ABSTRACT FROM AUTHOR]

Published
2019
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47. Research and innovation paving the way for climate neutrality in urban transport: Analysis of 362 cities on their journey to zero emissions.

Author

Christidis, Panayotis, Ulpiani, Giulia, Stepniak, Marcin, and Vetters, Nadja

Subjects
*CITIES & towns, *URBAN climatology, *ACTIVE biological transport, *CLIMATE change, *SMART cities, *ZERO emissions vehicles
Abstract

The EU Mission on Climate Neutral and Smart Cities is an ambitious initiative aiming to involve a wide range of stakeholders and deliver 100 climate-neutral and smart cities by 2030. We analysed the information submitted in the expressions of interest by 362 candidate cities. The majority of the cities' strategies for climate neutrality include urban transport as a main sector and combine the introduction of new technologies with the promotion of public transport and active mobility. We combined the information from the EU Mission candidate cities with data from the CORDIS and TRIMIS databases, and applied a clustering algorithm to measure proximity to foci of H2020 funding. Our results suggest that preparedness for the EU Mission is correlated with research and innovation activities on transport and mobility. Horizon 2020 activities specific to transport and mobility significantly increased the likelihood of a city to be a candidate. Among the various transport technology research pathways, smart mobility appears to have a major role in the development of solutions for climate neutrality. • Analysis of 362 candidate cities to the EU Mission on Climate Neutral and Smart Cities. • Urban transport is a main sector for climate neutrality. • Strategies combine new technologies, public transport and active mobility. • Horizon 2020 activities significantly increased the likelihood of a city to be a candidate. • Smart mobility has a major role in the development of solutions for climate neutrality. [ABSTRACT FROM AUTHOR]

Published
2024
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