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121.
Khaled A. Selim Salman S. Alharthi Abdelmonam M. Abu El-Hassan Nady A. Elneairy Laila A. Rabee Adel G. Abdel-Razek 《Molecules (Basel, Switzerland)》2021,26(20)
Fish oil is the primary source of long-chain omega-3 fatty acids, which are important nutrients that assist in the prevention and treatment of heart disease and have many health benefits. It also contains vitamins that are lipid-soluble, such as vitamins A and D. This work aimed to determine how the wall material composition influenced the encapsulation efficiency and oxidative stability of omega fish oils in spray-dried microcapsules. In this study, mackerel, sardine waste oil, and sand smelt fish oil were encapsulated in three different wall materials (whey protein, gum Arabic (AG), and maltodextrin) by conventional spray-drying. The effect of the different wall materials on the encapsulation efficiency (EE), flowability, and oxidative stability of encapsulated oils during storage at 4 °C was investigated. All three encapsulating agents provided a highly protective effect against the oxidative deterioration of the encapsulated oils. Whey protein was found to be the most effective encapsulated agent comparing to gum Arabic and maltodextrin. The results indicated that whey protein recorded the highest encapsulation efficiency compared to the gum Arabic and maltodextrin in all encapsulated samples with EE of 71.71%, 68.61%, and 64.71% for sand smelt, mackerel, and sardine oil, respectively. Unencapsulated fish oil samples (control) recorded peroxide values (PV) of 33.19, 40.64, and 47.76 meq/kg oil for sand smelt, mackerel, and sardine oils after 35 days of storage, while all the encapsulated samples showed PV less than 10 in the same storage period. It could be concluded that all the encapsulating agents provided a protective effect to the encapsulated fish oil and elongated the shelf life of it comparing to the untreated oil sample (control). The results suggest that encapsulation of fish oil is beneficial for its oxidative stability and its uses in the production of functional foods. 相似文献
122.
123.
Photoluminescence properties of thenardite activated with Eu 总被引:1,自引:0,他引:1
Aierken Sidike Rahman Abu Zayed Mohammad Saliqur Jui-Yang He K. Atobe N. Yamashita 《Journal of luminescence》2009,129(11):1271-1275
Na2SO4:Eu phosphors were prepared by heating pure natural thenardite with EuF3 at 900 °C for 20 min in air. The photoluminescence (PL) and excitation spectra of as-prepared and γ-ray-irradiated phosphors were observed at 300 K. The PL spectrum under 394 nm excitation consisted of strong narrow bands with peaks at 579, 592, 616, 652, 697 and 741 nm, assigned to the 5D0→7FJ (J=0, 1, 2, …, 5) transitions, respectively, within Eu3+. The PL spectrum under 340 nm excitation consisted of a broad Eu2+ band with a peak at 435 nm. The excitation spectrum obtained by monitoring the violet luminescence consisted of a weak band with a peak at approximately 261 nm and a broad Eu2+ band with a peak at approximately 338 nm. The relative efficiency of the violet luminescence of the γ-ray-irradiated phosphor at the exposure of 46 kGy increased up to 3.0 times that of the unirradiated phosphor. The enhancement of violet luminescence by γ-ray irradiation was ascribed to the conversion of Eu3+ to Eu2+ in Na2SO4. 相似文献
124.
Mohd Basyaruddin Abdul Rahman Naz Chaibakhsh Mahiran Basri Abu Bakar Salleh Raja Noor Zaliha Raja Abdul Rahman 《Applied biochemistry and biotechnology》2009,158(3):722-735
In this study, an artificial neural network (ANN) trained by backpropagation algorithm, Levenberg–Marquadart, was applied
to predict the yield of enzymatic synthesis of dioctyl adipate. Immobilized Candida antarctica lipase B was used as a biocatalyst for the reaction. Temperature, time, amount of enzyme, and substrate molar ratio were
the four input variables. After evaluating various ANN configurations, the best network was composed of seven hidden nodes
using a hyperbolic tangent sigmoid transfer function. The correlation coefficient (R
2) and mean absolute error (MAE) values between the actual and predicted responses were determined as 0.9998 and 0.0966 for
training set and 0.9241 and 1.9439 for validating dataset. A simulation test with a testing dataset showed that the MAE was
low and R
2 was close to 1. These results imply the good generalization of the developed model and its capability to predict the reaction
yield. Comparison of the performance of radial basis network with the developed models showed that radial basis function was
more accurate but its performance was poor when tested with unseen data. In further part of the study, the feedforward backpropagation
model was used for prediction of the ester yield within the given range of the main parameters. 相似文献
125.
Corticosteroids and related compounds containing the 20-keto-21-hydroxyl side chain such as betamethasone, betamethasone 9,11-epoxide, dexamethasone, and dexamethasone 9,11-epoxide have been found to undergo facile autooxidation on the 1,3-dihydroxyacetone side chain of their D-rings under strong alkaline conditions to yield five main degradants (17-formyloxy-17-acid, 17-acid, 21-aldehyde, 20-hydroxy-21-acid, and 17-ketone). The rate of the autooxidation was correlated with the strength and concentration of the base used in the reaction. A novel mechanism for the observed autooxidation is proposed, in which the facile oxidation of the presumed enolate (resulting from the carbanion at the 21-position) by molecular oxygen is the key step. The proposed autooxidation mechanism, supported by LC-MS isotope experiments using 18O2 as the oxidant, can satisfactorily explain the oxidative degradation patterns observed for corticosteroids containing the 20-keto-21-hydroxyl side chain. 相似文献
126.
Ethylene propylene diene monomer grafted with maleic ahydride (MAH-g-EPDM) was prepared by peroxide-initiated melt grafting of MAH onto EPDM using a HAAKE internal mixer at 180 °C and 60 rpm for 5 min. The effect of MAH-g-EPDM compatibilizer on the interactions, and tensile and morphological properties of halloysite nanotubes (HNTs) filled EPDM nanocomposites was investigated. The tensile properties of the nanocomposites were influenced by two major factors. The hydrogen bonding between MAH-g-EPDM and HNTs, which was confirmed by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), as well as the formation of EPDM-rich and HNT-rich areas, are the dominant effects on the tensile strength of the nanocomposites at low and high HNT loading, respectively. It was found that the cure time (t90), maximum torque (MH) and minimum torque (ML) of the compatibilized nanocomposites were increased after adding MAH-g-EPDM. The reinforcement mechanism of the compatibilized and un-compatibilized EPDM/HNT nanocomposites was also investigated based on morphological observations of the nanocomposites. 相似文献
127.
Yanuardi Raharjo Mohd Marsin Sanagi Wan Aini Wan Ibrahim Ahmedy Abu Naim Hassan Y. Aboul‐Enein 《Journal of separation science》2009,32(4):623-629
A liquid‐phase microextraction coupled with LC method has been developed for the determination of organophosphorus pesticides (methidation, quinalphos and profenofos) in drinking water samples. In this method, a small amount (3 μL) of isooctane as the acceptor phase was introduced continually to fill‐up the channel of a 1.5 cm polypropylene hollow fiber using a microsyringe while the hollow fiber was immersed in an aqueous donor solution. A portion of the acceptor phase (ca. 0.4 μL) was first introduced into the hollow fiber and additional amounts (ca. 0.2 μL) of the acceptor phase were introduced to replenish at intervals of 3 min until set end of extraction (40 min). After extraction, the acceptor phase was withdrawn and transferred into a 2 mL vial for a drying step prior to injection into a LC system. Parameters that affect the extraction efficiency were studied including the organic solvent, length of fiber, volume of acceptor and donor phase, stirring rate, extraction time, and effect of salting out. The proposed method provided good enrichment factors of up to 189.50, with RSD ranging from 0.10 to 0.29%, analyte recoveries of over 79.80% and good linearity ranging from 10.0 to 1.25 mg/L. The LOD ranged from 2.86 to 82.66 μg/L. This method was applied successfully to the determination of organophosphorus pesticides in selected drinking water samples. 相似文献
128.
Bromodimethylsulfonium bromide has been found to be an effective and regioselective reagent for alpha-monobromination of beta-keto esters and 1,3-diketones. A wide variety of beta-keto esters and 1,3-diketones undergo chemoselective alpha-monobromination with excellent yields at 0-5 degrees C or room temperature. The notable advantages of this protocol are no need of chromatographic separation, use of less hazardous reagent than molecular bromine, and no added base, Lewis acid, or other catalyst. 相似文献
129.
In this study, rubberized concrete samples were prepared by partial substitution (5 %, 10 % and 20 % replacements by volume) of sand by waste crumb rubber, and tested under impact three-point bending load, as well as static load. Three types of specimens (size 50?×?100?×?500 mm) namely, plain concrete, rubberized concrete, and double layer concrete (with rubberized concrete top and plain concrete bottom) were loaded to failure in a drop-weight impact machine by subjecting to 20 N weight from a height of 300 mm, and another three similar specimens were used for the static load test. In both the tests, the load–displacement and fracture energy of each specimen were investigated. Finite-element simulations were also performed to study the dynamic behaviors of the samples, by using LUSAS V.14 software. It was noticed that, the impact tup, and inertial and bending loads increased with the increase in the percentage of sand replacement by crumb rubber. It was interesting to observe that these effects were more significant in the double layer specimen compared to the plain and rubberized concrete samples. The static peak bending load always decreased with increase of rubber in the mix. In general, the strength and energy absorbing capability of rubberized concrete was better under impact loading than under static loading. The simulated load against displacement behaviors of all the samples were validated by the experimental results. 相似文献
130.
Heba Khader Victor Solodushko Abu Bakr Al-Mehdi Jonathon Audia Brian Fouty 《Journal of fluorescence》2014,24(2):305-311
Tetracycline-inducible systems allow for either suppression or induction of transgene expression to facilitate studies of cell physiology. Doxycycline is a preferred inducer for these gene expression systems due to its membrane permeability; however, the heterocyclic structure of doxycycline exhibits fluorogenic properties that can potentially bias measurement of other fluorochromes. Thus the simultaneous use of tetracycline-inducible systems and fluorescent proteins as reporter genes or as intracellular biosensors may lead to potentially confounding results. Herein, using cells which co-express the ratiometric redox sensitive intracellular reporter, roGFP, and a tetracycline-inducible reporter plasmid encoding the reporter gene, mCherry, as a model system, we describe the overlapping intracellular fluorescent signals between doxycycline and commonly used intracellular fluorescent probes. In our cells, the addition of doxycycline to cells caused a dose- and time-dependent increase in cell fluorescence with 405 nm excitation which overlapped with that of the oxidized configuration of roGFP. Incubating cells in concentrations of doxycycline less than 1 μg/mL and removing doxycycline from the media 60 min before performing experiments eliminated fluorescence interference while still maintaining maximal reporter transgene activation. 相似文献