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11.
Railean-Plugaru Viorica Pomastowski Pawel Buszewski Boguslaw 《Journal of dairy science》2021,104(3):2480-2498
The present research emphasizes the use of safe, inexpensive, and available whey using Lactobacillus paracasei as a source in silver nanocomposite synthesis as an alternative bioactive agent for dairy and biomedical applications. Through the multiinstrumental approach used in this study based on spectroscopic and microscopic methods as well as spectrometric techniques, the characterization and evaluation of silver composites and their antimicrobial and antiradical properties were enabled. Synthesized silver nanocomposites have been found in form of nanocrystals, naturally coated by an organic surface with high antimicrobial and antiradical properties. Furthermore, this work also presents an innovative approach regarding the organic surface (naturally secreted by the bacteria isolated from whey) of the core of nanoparticles, which has already been explored and therefore is starting to supplement the scientific approach concerning biologically synthesized nanoparticles. This work also presents a general frame on the resistance subject by performing the trial interaction of commercially available antibiotics (kanamycin and ampicillin) with new bioactive compounds that can create novel knowledge on complementing their action. Moreover, synthesized silver nanocomposites have shown great antioxidant and antimicrobial effects against various foodborne pathogens from dairy products and drug resistance pathogens found in the medical area to rank on the top of mortality rate. 相似文献
12.
Temperature influence on the behavior of polysulfone‐b‐poly(alkylene oxide)‐b‐poly(dimethylsiloxane) triblock copolymers in a selective solvent 下载免费PDF全文
Triblock copolymers containing polysulfone, poly(alkylene oxide), and poly(dimethylsiloxane) segments were obtained by addition of preformed α,ω‐bis(hydrogensilyl) poly(dimethylsiloxane) oligomers to alyl end‐capped poly(alkylene oxide)‐b‐polysulfone. Viscometric and UV absorption measurements were carried out in dilute 1,2‐dichlorethane solutions, in the temperature range of 20–75°C. The specific interactions exhibited by the block copolymers in a selective solvent are influenced by the copolymer composition and temperature. The results point to a conformational transition phenomenon, located around 55°C, which is attributed to the transition from a segregated to a pseudo‐Gaussian conformation through a compressed‐segregated conformation. POLYM. ENG. SCI., 57:114–118, 2017. © 2016 Society of Plastics Engineers 相似文献
13.
Assessment of cleaning effectiveness for new ecological systems on ancient tempera icon by complementary microscopy techniques 下载免费PDF全文
Silvea Pruteanu Viorica Vasilache Irina Crina Anca Sandu Ana‐Maria Budu Ion Sandu 《Microscopy research and technique》2014,77(12):1060-1070
The study presents an old icon painted in egg tempera on lime wood, with a poor conservation condition and clogged dirt deposits. The icon is attributed to an anonymous painter of XIXth century and to the neo‐classical style of painting. The painting layer was done with only a hand full of pigments, earth colors that were often used in painting the icons from XVIIth to XIXth century in Eastern Europe, that have Byzantine influences. Taking into consideration the nature and the structure of the materials from the upper layers of the painting, affected by deposits of dirt over time, a series of cleaning recipes were studied, using the so called cleaning tests with compatible mixtures of different juices and infusion from indigenes plants, that were freshly done and odorless. A low alkaline 95% ethyl alcohol solution, combined with a few drops of ammoniac 25%, was used as a reference system, due to its compatibility with the greasy deposits found on the polychrome layer and on the wood. The cleaning capacity of the new systems used, in comparison with the standard solution, was analyzed through modern analytical methods of evaluating the degree of cleaning, more exactly by means of visible and UV reflectography, CIE L*a*b* colorimetry by reflection assisted by SEM‐EDX and IR spectroscopy. Microsc. Res. Tech. 77:1060–1070, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
14.
Viorica Hamciuc Diana Giurgiu Elena Butuc Mihai Marcu Cãtãlin Ionescu Lucia Pricop 《Polymer Bulletin》1996,37(3):329-336
The synthesis of polysulfone-polydimethylsiloxane (PSU-PDMS)linear block copolymers has been carried out in solution by condensation of chloro-terminated bisphenol A, diphenylsulfone and , -di (hydrogensilyl)-polydimethylsiloxane with Si–C bond. 1H-NMR spectra of the block copolymers allow the estimation of siloxane and polysulfone ratio. The molecular weight of the polysulfone and polysiloxane oligomers and the block copolymers was determined by GPC. Thermogravimetric analysis indicates a thermal stability of block copolymers up to 400°C and allows estimation of the process activation energy. Microphase separation of the block copolymers was observed by differential scanning calorimetry (DSC). 相似文献
15.
Dumitru Cebrucean Viorica Cebrucean Ioana Ionel Hartmut Spliethoff 《Clean Technologies and Environmental Policy》2017,19(2):451-470
In this paper, the performances of two iron-based syngas-fueled chemical looping (SCL) systems for hydrogen (H2) and electricity production, with carbon dioxide (CO2) capture, using different reactor configurations were evaluated and compared. The first investigated system was based on a moving bed reactor configuration (SCL-MB) while the second used a fluidized bed reactor configuration (SCL-FB). Two modes of operation of the SCL systems were considered, namely, the H2 production mode, when H2 was the desired product from the system, and the combustion mode, when only electricity was produced. The SCL systems were modeled and simulated using Aspen Plus software. The results showed that the SCL system based on a moving bed reactor configuration is more efficient than the looping system with a fluidized bed reactor configuration. The H2 production efficiency of the SCL-MB system was 11 % points higher than that achieved in the SCL-FB system (55.1 % compared to 44.0 %). When configured to produce only electricity, the net electrical efficiency of the SCL-MB system was 1.4 % points higher than that of the SCL-FB system (39.9 % compared to 38.5 %). Further, the results showed that the two chemical looping systems could achieve >99 % carbon capture efficiency and emit ~2 kg CO2/MWh, which is significantly lower than the emission rate of conventional coal gasification-based plants for H2 and/or electricity generation with CO2 capture. 相似文献
16.
Vasile I. Parvulescu Claudia Visinescu Viorica Parvulescu Victor Marcu Francis Levy 《Catalysis Today》2006,118(3-4):433-439
Ta-doped photocatalysts were prepared using three different techniques: reactive d.c.-magnetron sputtering, sol–gel and grafting of tantalum on MCM-41 and TiO2. The composition of the catalysts prepared by reactive d.c.-magnetron sputtering consisted in tantalum and titania, while that of sol–gel and grafted catalysts of Ta–titania–silica mixed oxides. The characterization of these catalysts was carried out using the adsorption-desorption isotherms of N2 at 77 K, X-ray diffraction (XRD) patterns, small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), XPS, TEM, and 29Si- and 181Ta-CP/MAS NMR spectra. The behavior of these photocatalysts was checked in acetone degradation. The photocatalytic tests indicate that, depending on the preparation conditions and tantalum content, an enhancement of the activity occurs as compared with pure titania. Sol–gel and Ta-grafted MCM and TiO2 catalysts exhibited a rather poor activity, which was correlated with the lack of crystallinity of titania. 相似文献
17.
Viorica Mariela Ungureanu 《Dynamical Systems: An International Journal》2008,23(3):333-350
The aim of this article is to discuss the uniform observability property of general linear differential equations with multiplicative white noise in Hilbert spaces. Based on perturbation theory for evolution operators on Hilbert Schmidt spaces and on the space of nuclear operators, new representations of the covariance operators associated to the mild solutions of the investigated stochastic differential equations are given. Using these results we obtain deterministic characterizations of the stochastic uniform observability property. We also identify an entire class of stochastic differential equations which are never stochastic uniformly observable. Some examples will illustrate the theory. 相似文献
18.
Summary The thermal behavior of several formulations consisting of ethylene-propylene elastomers and acrylonitrile-butadiene rubber
was investigated by differential scanning calorimetry. The sample compositions cover the whole concentration range of ((EPDM,
EPR)/NBR = 100/0, 20/80, 40/60, 60/40, 80/20 and 0/100). The evaluation of molar enthalpies for studied polymer blends allowed
to calculate molar capacities at various temperatures from 335 K up to 450 K. Due to the lack of additivity in the molar capacities
of studied blends, the contributions of each component to the overall values of Cp are calculated. The dependency of component contributions on their concentrations follows a first order function, which explains
the existence of a certain interaction between components. 相似文献
19.
Cebrucean Dumitru Cebrucean Viorica Ionel Ioana 《Clean Technologies and Environmental Policy》2020,22(1):153-169
Clean Technologies and Environmental Policy - Coal-fired power plants are the largest source of carbon dioxide (CO2) emissions into the atmosphere, and these emissions can be effectively reduced by... 相似文献
20.