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91.
Reactive separation technologies were proposed recently for fatty acid methyl esters (FAME) production, providing significant benefits such as minimal capital and operating cost savings. One approach is to use a reactive dividing-wall column (R-DWC) for the biodiesel production process. However, since the R-DWC is designed for a quaternary reactive system – two reactants (one in excess) and two products – more difficulties concerning the process control may be expected considering the high degree of integration of the process. 相似文献
92.
l-Lactic acid biosensor based on multi-layered graphene 总被引:1,自引:1,他引:0
Antonio Radoi Alexandru Cosmin Obreja Sandra A. V. Eremia Adina Bragaru Adrian Dinescu Gabriel-Lucian Radu 《Journal of Applied Electrochemistry》2013,43(10):985-994
Pristine graphene platelets and graphene oxide were used as electrode modifiers, aiming the investigation of their electrochemical efficacy towards β-nicotinamide adenine dinucleotide (NADH). The electrochemical detection of NADH is one of the most studied areas of bioelectroanalysis because of the ubiquity of NAD(P)H-based enzymatic reactions in nature. Commercially available graphene and laboratory prepared graphene oxide were used to modify glassy carbon electrodes and the behaviour of such modified electrodes against potassium ferricyanide (III) and NADH was reported. Relying on the graphene-modified transducer, l-lactic dehydrogenase (l-LDH) was successfully immobilised in a 1 % Nafion® membrane. The developed biosensor, working at +250 mV versus Ag/AgCl reference electrode, was used to assess l-lactic acid in four different types of yogurts, revealing an l-lactic acid concentration ranging between 0.3 and 0.6 %. 相似文献
93.
Wael Mousa Farinazleen Mohd. Ghazali Selamat Jinap Hasanah Mohd. Ghazali Son Radu 《Journal of food science》2013,78(1):M56-M63
Abstract: The aim of this study was to model the radial growth rate and to assess aflatoxin production by Aspergillus flavus as a function of water activity (aw 0.82 to 0.92) and temperature (12 to 42 °C) on polished and brown rice. The growth of the fungi, expressed as colony diameter (mm) was measured daily, and the aflatoxins were analyzed using HPLC with a fluorescence detector. The growth rates were estimated using the primary model of Baranyi, which describes the change in colony radius as a function of time. Total of 2 secondary models were used to describe the combined effects of aw and temperature on the growth rates. The models were validated using independent experimental data. Linear Arrhenius–Davey model proved to be the best predictor of A. flavus growth rates on polished and brown rice followed by polynomial model. The estimated optimal growth temperature was around 30 °C. A. flavus growth and aflatoxins were not detected at 0.82 aw on polished rice while growth and aflatoxins were detected at this aw between 25 and 35 °C on brown rice. The highest amounts of toxins were formed at the highest aw values (0.90 to 0.92) at a temperature of 20 °C after 21 d of incubation on both types of rice. Nevertheless, the consistencies of toxin production within a wider range of aw values occurred between 25 to 30 °C. Brown rice seems to support A. flavus growth and aflatoxin production more than the polished rice. Practical Application: The developed models can be used to estimate to what extent the change in grain ecosystem conditions affect the storage stability and safety of grains without the need for running long‐standing storage study. By monitoring the intergranular relative humidity and temperature at different locations in the storage facility and inputting these data into the models, it is directly possible to assess either the conditions are conductive for the growth of A. flavus or aflatoxin production. 相似文献
94.
The physico-chemical properties of solvent-extracted oil from the seeds of noni (Morinda citrifolia L.), spinach (Spinacia oleracea L.), lady’s finger (Abelmoschus esculentus (L.) Moench), bitter gourd (Momordica charantia L.), mustard (Brassica nigra (L.) Koch), and the dried kernel (copra) of coconut (Cocos nucifera L.) were characterized. Among these sources, spinach seed had the lowest oil content (4.5 ± 0.4%) while coconut kernel had the highest oil content (63.1 ± 2.8%). Palmitic, oleic, and linoleic acids were the major fatty acids for spinach, lady’s finger and noni seed oils, while erucic, eleostearic, and lauric acids were the major fatty acids for mustard seed oil, bitter gourd seed oil, and coconut kernel oil, respectively. All of the oils possessed at least three major peaks in their triacylglycerol profiles except for bitter gourd seed oil which had only one major peak (1-stearoyl, 2,3-dieleostearoyl). The last endothermic peaks were –12.4, –6.0, 6.8, 57.7, 2.7, and 24.3ºC for noni, spinach, lady’s finger, bitter gourd and mustard seed oils, and coconut oil, respectively. Initially, the solid fat content of bitter gourd seed oil decreased gradually, but became rapidly after 50 until 60ºC. Coconut oil had its solid fat content reduced rapidly around 14 to 28ºC. 相似文献
95.
M. R. Szabo D. Radu S. Gavrilas D. Chambre C. Iditoiu 《International Journal of Food Properties》2013,16(3):535-545
Tinctures of eleven plants used as spices (basil, celery, dill, horsetail, lovage, marjoram, milfoil, oregano, parsley, rosemary, and thyme) were tested for their antiradical properties by means of the DPPH (1,1-diphenyl-2-picrylhydrazyl) assay over a two year period. Seven of these plants (basil, lovage, marjoram, milfoil, oregano, rosemary and thyme) were selected to obtain a mixture, which was tested in situ as antioxidant on vegetable and animal fats by an accelerated oxidation test at 110°C. The herbal extract also showed antimicrobial activity against Staphylococcus aureus (ATCC 25923), Streptococcus pyogenes (ATCC 49399), Escherichia coli (ATCC 25922) and Candida albicans (ATCC 24433). 相似文献
96.
In this article we introduce a new public digital watermarking technique for video copyright protection working in the discrete wavelet transform domain. The scheme uses binary images as watermarks. These are embedded in the detail wavelet coefficients of the middle wavelet sub-bands. The method is a combination of spread spectrum and quantisation-based watermarking. Every bit of the watermark is spread over a number of wavelet coefficients with the use of a secret key. The resilience of the watermarking algorithm was tested against a series of eight different attacks using different videos. To improve the resilience of the algorithm we use error correction codes and embed the watermark with spatial and temporal redundancy. The proposed method achieves a very good perceptual quality with mean peak signal-to-noise ratio values of the watermarked videos of more than 40 dB and high resistance to a large spectrum of attacks. 相似文献
97.
Layer splitting by helium and/or hydrogen implantation and wafer bonding was applied to transfer thin single-crystalline ferroelectric layers onto different substrates. The optimum conditions for achieving blistering/splitting after post-implantation annealing were experimentally obtained for LiNbO3, LaAlO3, SrTiO3 single crystals and PLZT ceramic. Under certain implantation conditions large area exfoliation instead of blistering occurs after annealing of as-implanted substrates. Small area single-crystalline layer transfer was successfully achieved. 相似文献
98.
A higher order shear deformation theory is used to investigate the instability associated with delaminated composite plates
subject to dynamic loads. Both transverse shear and rotary inertia effects are taken into account. The procedure is implemented
using the finite element method. Delamination is modeled using the penalty parameter approach. The natural frequencies are
computed and compared with NASTRAN 3D results and available experimental data. The effect of delamination on the critical
buckling load and the first two instability regions is investigated for various loading conditions, plate thickness and boundary
conditions. As expected the natural frequencies and the critical buckling load of the delaminated plate are lower than those
of the nondelaminated plate. They decrease with increase in delamination length. Increase in delamination length causes instability
regions to be shifted to lower parametric resonance frequencies and the normalized width of the instability regions to increase. 相似文献
99.
100.
Radu Nicolae Revnic Gabriela Fabiola tiufiuc Valentin Toma Anca Onaciu Alin Moldovan Adrian Bogdan
igu Eva Fischer-Fodor Romulus Tetean Emil Burzo Rare Ionu tiufiuc 《International journal of molecular sciences》2022,23(15)
We report a very simple, rapid and reproducible method for the fabrication of anisotropic silver nanostars (AgNS) that can be successfully used as highly efficient SERS substrates for different bioanalytes, even in the case of a near-infra-red (NIR) excitation laser. The nanostars have been synthesized using the chemical reduction of Ag+ ions by trisodium citrate. This is the first research reporting the synthesis of AgNS using only trisodium citrate as a reducing and stabilizing agent. The key elements of this original synthesis procedure are rapid hydrothermal synthesis of silver nanostars followed by a cooling down procedure by immersion in a water bath. The synthesis was performed in a sealed bottom flask homogenously heated and brought to a boil in a microwave oven. After 60 s, the colloidal solution was cooled down to room temperature by immersion in a water bath at 35 °C. The as-synthesized AgNS were washed by centrifugation and used for SERS analysis of test molecules (methylene blue) as well as biological analytes: pharmaceutical compounds with various Raman cross sections (doxorubicin, atenolol & metoprolol), cell lysates and amino acids (methionine & cysteine). UV-Vis absorption spectroscopy, (Scanning) Transmission Electron Microscopy ((S)TEM) and Atomic Force Microscopy (AFM) have been employed for investigating nanostars’ physical properties. 相似文献