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11.
Oliwia Metryka Daniel Wasilkowski Anna Nowak Magorzata Adamczyk-Habrajska Agnieszka Mrozik 《International journal of molecular sciences》2020,21(23)
Due to the systematic increase in the production of nanomaterials (NMs) and their applications in many areas of life, issues associated with their toxicity are inevitable. In particular, the performance of heterogeneous NMs, such as nanocomposites (NCs), is unpredictable as they may inherit the properties of their individual components. Therefore, the purpose of this work was to assess the biological activity of newly synthesized Cu/TiO2-NC and the parent nanoparticle substrates Cu-NPs and TiO2-NPs on the bacterial viability, antioxidant potential and fatty acid composition of the reference Escherichia coli and Bacillus subtilis strains. Based on the toxicological parameters, it was found that B. subtilis was more sensitive to NMs than E. coli. Furthermore, Cu/TiO2-NC and Cu-NPs had an opposite effect on both strains, while TiO2-NPs had a comparable mode of action. Simultaneously, the tested strains exhibited varied responses of the antioxidant enzymes after exposure to the NMs, with Cu-NPs having the strongest impact on their activity. The most considerable alternations in the fatty acid profiles were found after the bacteria were exposed to Cu/TiO2-NC and Cu-NPs. Microscopic images indicated distinct interactions of the NMs with the bacterial outer layers, especially in regard to B. subtilis. Cu/TiO2-NC generally proved to have less distinctive antimicrobial properties on B. subtilis than E. coli compared to its parent components. Presumably, the biocidal effects of the tested NMs can be attributed to the induction of oxidative stress, the release of metal ions and specific electrochemical interactions with the bacterial cells. 相似文献
12.
Karolina M. Wójciak Dariusz M. Stasiak Joanna Stadnik Karolina Ferysiuk Anna Kononiuk 《International Journal of Food Science & Technology》2019,54(1):75-83
In this study, the influence of sonication time on the biogenic amines formation as a critical point in uncured dry-fermented beef manufacturing was studied. Samples of musculus semimembranosus were sonicated at different times (5 and 10 min) using ultrasound cold bath (4 °C) in acid whey (US 40 kHz and acoustic power 480 W). The effect of sonication on biogenic amine (BA) formation was investigated during 93 days of ripening period. Other parameters (pH value, water activity, microbial counts) that might provide further information on the product under study were also determined. The use of ultrasound during beef marinating in acid whey has a positive effect on retarding histamine (HIS), cadaverine (CAD), tyramine (TYR) and putrescine (PUT) formation. Moreover, the sonication treatment did not inhibit the growth of lactic acid bacteria (LAB) in dry-fermented beef during the whole ripening period. The pathogen bacteria (Staphylococcus aureus, Clostridium sp., Listeria monocytogenes) were not detected in all samples neither after 31 nor after 93 days of ripening period. 相似文献
13.
David J. Lawrence Brianna L. Smith Cameron D. Collard Keyton A. Elliott Kyle L. Fakhoury Jeffery D. Mangold Anna N. Soyka 《International Journal of Hydrogen Energy》2021,46(2):1642-1655
Monolithically-integrated tandem photoanodes were fabricated on substrates consisting of epitaxial n-GaAs1-xPx (x ? 0.32) grown on n+-GaAs wafers. A p+-n junction photovoltaic (PV) cell was first formed by zinc diffusion into the n-GaAs0.68P0.32 from a deposited ZnO coating. After diffusion the ZnO serves as a transparent electrical contact to the resulting p+-GaAs0.68P0.32 surface layer. Transparent, conducting SnO2:F provides chemical and mechanical protection for the ZnO and the underlying PV cell, and it electrically connects this cell to a top BiVO4 photocatalyst layer. In some photoanodes, a WO3 thin film was interposed between the SnO2:F and BiVO4. All oxide coatings were produced by ultrasonic spray pyrolysis except WO3, which was spin coated. Unassisted (unbiased) solar water splitting was achieved, with a solar-to-hydrogen efficiency approaching 2%, without addition of any co-catalyst to the BiVO4 surface. This work can provide insights to other researchers regarding scalable, low cost approaches for the planar monolithic integration of oxide photoanode materials with PV cells to create new tandem devices. 相似文献
14.
Valentina I. Simagina Pavel A. Storozhenko Olga V. Netskina Oksana V. Komova Galina V. Odegova Yury V. Larichev Arcady V. Ishchenko Anna M. Ozerova 《Catalysis Today》2008,138(3-4):253
Catalytic hydrolysis of NaBH4 and NH3BH3 has been studied. It was shown that the nature of the support and the active component of the catalyst affect the H2 generation rate. Despite similar sizes of rhodium particles formed on the surface of different supports (γ-Al2O3, TiO2, carbon), their reactivity is different. Rh/TiO2 with low rhodium concentration (1 wt.%) is the most active catalyst both in the hydrolysis of NaBH4 and NH3BH3. The obtained results show that the rhodium chloride interaction with titania determines the reactivity of rhodium particles formed under action of NaBH4 medium. TEM, DRS UV–vis and XPS were used to characterize the catalysts. 相似文献
15.
Ottavia Colombo Simona Villani Giovanna Pinelli Claudia Trentani Maurizia Baldi Orazio Tomarchio Anna Tagliabue 《Nutrition journal》2008,7(1):5
Background
Excess body fat is a major risk factor for disease primarily due to its endocrine activity. In recent years several criteria have been introduced to evaluate this factor. Nevertheless, treatment need is currently assessed only on the basis of an individual's Body Mass Index (BMI), calculated as body weight (in kg) divided by height in m2. The aim of our study was to determine whether application of the BMI, compared to adiposity-based criteria, results in underestimation of the number of subjects needing lifestyle intervention. 相似文献16.
The development of porosity in the course of carbonization of a flame coal, original and pre-oxidized, was studied by means of the adsorption of benzene and carbon dioxide. The results were compared with corresponding data for cokes from a xylitic brown coal. The influence of coal oxygen content on the formation of coke porosity and its thermal dependence is discussed. 相似文献
17.
Present-day computer-aided design (CAD) packages play only a small part in the area of mechanical engineering design, which involves the synthesis and embodiment of physical components to perform a pre-determined function without unwanted side effects. The computer cannot properly help the designer in this task until it is able to capture and process the function requirements of the design. This paper describes the computer system being developed for this purpose at the Engineering Design Centre at Cambridge University Engineering Department. The paper also explores some of the geometrical and programming implications raised. 相似文献
18.
Hydrocarbon exploration risk evaluation through uncertainty and sensitivity analyses techniques 总被引:1,自引:0,他引:1
Paolo Ruffo Livia Bazzana Alberto Consonni Anna Corradi Andrea Saltelli Stefano Tarantola 《Reliability Engineering & System Safety》2006,91(10-11):1155-1162
The evaluation of the exploration risk in the oil industry is a fundamental component of the decision process related to the exploratory phase. In this paper the two basic components of the exploratory risk: trap geometry and trapped hydrocarbon quantities (fluid), are compounded in a single coherent uncertainty and sensitivity approach. The results clarify that the model geometry influences each Petroleum System Modeling step and that the geometric uncertainty is correlated with the fluid uncertainty. The geometric uncertainty evaluation makes use of geostatistical techniques that produce a number of possible realizations of the trap geometry, all compatible with available data. The evaluation of the fluid uncertainty, through a Monte Carlo methodology, allows us to compute the possible quantities of oil and gas, generated in a basin and migrated from the hydrocarbon source location to each single trap. The final result is the probability distribution of oil and gas for each trap in the basin, together with other useful indicators like: the hydrocarbon filling probability map, the closure probability map, the drainage area probability map, the spilling paths probabilities, the trap-filling scenarios. 相似文献
19.
This paper presents the current understanding of the flame retardant mechanism of Casico?. The study includes the flame retardant effect of each individual component: ethylene–acrylate copolymer, chalk and silicone elastomer, as well as the formation of an intumescent structure during heating. The flame retardant properties were investigated by cone calorimetry and oxygen index tests. To obtain insight into the flame retardant mechanism, heat treatment under different conditions has also been performed. The results indicate that the flame retardant mechanism of Casico is complex and is related to a number of reactions, e.g. ester pyrolysis of acrylate groups, formation of carbon dioxide by reaction between carboxylic acid and chalk, ionomer formation and formation of an intumescent structure stabilized by a protecting char. Special emphasis is given to the formation of the intumescent structure and its molecular structure as evaluated from 13C MAS‐NMR and 29Si MAS‐NMR, ESCA and XRD analysis. After treatment at 500°C the intumescent structure consists mainly of silicon oxides and calcium carbonate and after treatment at 1000°C the intumescent structure consists of calcium silicate, calcium oxide and calcium hydroxide. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
20.
Pyrrole was successfully electropolymerized at a copper–nickel electrode in a near-neutral sodium oxalate solution containing Cu2+ cations to generate a homogenous and adherent polypyrrole film. The presence of the Cu2+ ions increased both the rate of the electropolymerization reaction and the adherence of the polymer at the CuNi interface. In the absence of these cations, oxidation of the electrode occurred generating a nickel-rich layer that was not sufficiently conducting, under the electropolymerization conditions employed, to facilitate the electron-transfer reaction and the electropolymerization of pyrrole.These films remained stable and exhibited significant corrosion protection properties in acidified and neutral 0.1 mol dm−3 NaCl solutions even on polarization of the electrodes to high anodic potentials. 相似文献