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51.
Melt Production and Antimicrobial Efficiency of Low-Density Polyethylene (LDPE)-Silver Nanocomposite Film 总被引:1,自引:0,他引:1
Maryam Jokar Russly Abdul Rahman Nor Azowa Ibrahim Luqman Chuah Abdullah Chin Ping Tan 《Food and Bioprocess Technology》2012,5(2):719-728
Colloidal silver nanoparticles with a size of 5.5 ± 1.1 nm were prepared by chemical reduction using polyethylene glycol (PEG).
Silver nanoparticles were incorporated into low-density polyethylene (LDPE) by melt blending and subsequent hot pressing at
140 °C to produce nanocomposite film with an average thickness of 0.7 mm. PEG was added at 5% weight of polymer as a compatibilizer
agent in order to prevent agglomeration and provide uniform distribution of nanoparticles in polymer matrix. Antimicrobial
activity of silver nanocomposites against Escherichia coli ATCC 13706, Staphylococcus aureus ATCC12600, and Candida albicans ATCC10231 was evaluated by semi-qualitative agar diffusion test and quantitative dynamic shake flask test. Mechanical properties
of nanocomposites were not significantly different from silver-free LDPE-containing PEG films (p > 0.05), and silver nanoparticles did not form chemical bonding with the polymer. LDPE-silver nanocomposite samples by more
than 6.69 ppm silver nanoparticles showed considerable antimicrobial clear zone. LDPE-silver nanocomposite affected growth
kinetic parameters of the examined bacteria and is more efficient on S. aureus than E. coli. Polyethylene-silver nanocomposites containing 22.64 ppm silver nanoparticles could reduce 57.8% growth rate and 23.3% maximum
bacterial concentration and increase 35.8% lag time of S. aureus. This study shows the potential use of LDPE-silver nanocomposite as antimicrobial active film. Antimicrobial efficiency of
silver nanocomposite depends on silver nanoparticles concentration; however, high level of silver nanoparticles may lead to
weakening of mechanical properties. 相似文献
52.
Aazam Aarabi Maryam Mizani Masoud Honarvar Hossein Faghihian Abbas Gerami 《Sensing and Instrumentation for Food Quality and Safety》2016,10(1):42-47
Extraction of ferulic acid from sugar beet pulp was carried out using three extraction solvents, sodium hydroxide (0.5, 1, 2 M), methanol and their mixture (alkaline methanolic solvent). The Ferulic acid extracted by each solvent was identified and quantified by HPLC method and the effects of solvent type, concentration and reaction time on ferulic acid solubilisation were assessed. There were differences in the contents of products extracted in the experiment conditions. The minimum amount of ferulic acid was obtained from methanolic extract while the highest concentrations (957.4 mg/L ferulic acid) were obtained employing the highest NaOH concentration (2 M), and reaction time (12 h), so phenolic compounds are better released with alkaline hydrolysis than in methanol conditions. Finally a simple procedure for the purification of ferulic acid from the alkaline extracts is presented and evaluated by FT-IR spectrum. 相似文献
53.
Hashem Asgharnejad Ehsan Khorshidi Nazloo Maryam Madani Larijani Nima Hajinajaf Hamidreza Rashidi 《Comprehensive Reviews in Food Science and Food Safety》2021,20(5):4779-4815
Food processing is among the greatest water-consuming industries with a significant role in the implementation of sustainable development goals. Water-consuming industries such as food processing have become a threat to limited freshwater resources, and numerous attempts are being carried out in order to develop and apply novel approaches for water management in these industries. Studies have shown the positive impact of the new methods of process integration (e.g., water pinch, mathematical optimization, etc.) in maximizing water reuse and recycle. Applying these methods in food processing industries not only significantly supported water consumption minimization but also contributed to environmental protection by reducing wastewater generation. The methods can also increase the productivity of these industries and direct them to sustainable production. This interconnection led to a new subcategory in nexus studies known as water-food-environment nexus. The nexus assures sustainable food production with minimum freshwater consumption and minimizes the environmental destructions caused by untreated wastewater discharge. The aim of this study was to provide a thorough review of water-food-environment nexus application in food processing industries and explore the nexus from different aspects. The current study explored the process of food industries in different sectors regarding water consumption and wastewater generation, both qualitatively and quantitatively. The most recent wastewater treatment methods carried out in different food processing sectors were also reviewed. This review provided a comprehensive literature for choosing the optimum scenario of water and wastewater management in food processing industries. 相似文献
54.
55.
Mahdi Ahmadi Monireh Mahmoodi Maryam Shoaran Fereshteh Nazari-Khanamiri Jafar Rezaie 《International journal of molecular sciences》2022,23(22)
There remains a vital necessity for new therapeutic approaches to combat metastatic cancers, which cause globally over 8 million deaths per year. Mesenchymal stem cells (MSCs) display aptitude as new therapeutic choices for cancer treatment. Exosomes, the most important mediator of MSCs, regulate tumor progression. The potential of harnessing exosomes from MSCs (MSCs-Exo) in cancer therapy is now being documented. MSCs-Exo can promote tumor progression by affecting tumor growth, metastasis, immunity, angiogenesis, and drug resistance. However, contradictory evidence has suggested that MSCs-Exo suppress tumors through several mechanisms. Therefore, the exact association between MSCs-Exo and tumors remains controversial. Accordingly, the applications of MSCs-Exo as novel drug delivery systems and standalone therapeutics are being extensively explored. In addition, engineering MSCs-Exo for targeting tumor cells has opened a new avenue for improving the efficiency of antitumor therapy. However, effective implementation in the clinical trials will need the establishment of standards for MSCs-Exo isolation and characterization as well as loading and engineering methods. The studies outlined in this review highlight the pivotal roles of MSCs-Exo in tumor progression and the promising potential of MSCs-Exo as therapeutic drug delivery vehicles for cancer treatment. 相似文献
56.
Mohammad?Taghi?GoldaniEmail author Reza?SandaroosEmail author Ali?Mohmmadi Maryam?Goharjoo 《Polymer Bulletin》2012,68(3):755-773
A series of titanium aminotropone complexes bearing a pair of chelating [O–N] ligands have been synthesized and used for polymerization
of ethylene successfully. Ethylene polymerization reactions were carried out at different conditions using the prepared catalysts.
The activities for ethylene polymerization were significantly dependent on the catalyst structure. The polymerization activity
increased with increasing of the both monomer pressure and [MAO]:[Ti] ratio. The highest activity of the catalysts was obtained
at about 30–40 °C. It was demonstrated that unlike the high performance Ti–FI catalysts, bis(aminotropone) Ti catalysts do
not require the presence of steric bulk in close proximity to the oxygen moiety. Introduction of the bulky alkyl substitution
next to the oxygen moiety decreased the activity of the catalysts. Density Functional Theory (DFT) studies reveal that the
active species derived from these catalysts normally possess higher electrophilicity nature compared with those produced using
bis(phenoxy-imine) Ti catalysts (Ti–FI catalysts). Hydrogen was used as the chain transfer agent. The activities of the catalysts
were increased with hydrogen concentration to some extent, but the M
v values of the obtained polymers were decreased. Crystallinity and melting point of the obtained polymer were between 42–62%
and 102–124 °C, respectively. Higher pressure increased both the crystallinity and the M
v values of the resulting polymers. The catalyst 8a also produced PE with almost narrow polydispersities (1.10–2.55) as is typical for single-site catalysts. However, PDI was
broadened by time. 相似文献
57.
In this paper a general review on different membrane processes and membrane reactors was done. As the main aim of this paper is to review the application of membrane processes in petrochemical industry, processes such as olefin/paraffin separation, light solvent separation, solvent dewaxing, phenol and aromatic recovery, dehydrogenation, oxidative coupling of methane and steam reforming of methane were discussed in detail. Besides, separation using polymer-inorganic nano composite membranes and wastewater treatment using membrane bio-reactors were reviewed. 相似文献
58.
Ali Nabipour Chakoli Jiehe Sui Maryam Amirian Wei Cai 《Journal of Polymer Research》2011,18(6):1249-1259
Well-dispersed multiwall carbon nanotubes (MWCNTs) were prepared by grafting poly(L-lactide-co-ε-caprolactone) (PLACL) biodegradable copolymer onto the sidewall of hydroxylated MWCNTs using oligomeric L-lactide (LA) and ε-caprolactone (CL). After preparation of MWCNT/PLACL composites, the effect of functionalized MWCNTs on
crystallinity of PLACL was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning
calorimetry (DSC), dynamic mechanical analysis (DMA), and polarized light optical microscopy (POM). The surface functionalization
effectively improved the dispersion and adhesion of MWCNTs which acted as reinforcing filler in the PLACL polymer matrix and
hence improved the physical and thermomechanical properties of the nanocomposites. The glass transition temperature (T
g) and the crystallinity of nanocomposites decreased in comparison with those of neat PLACL when the concentration of functionalized
MWCNTs in nanocomposites was 0.5 wt%. With further increment in concentration of functionalized MWCNTs, the T
g of composites increased until the T
g of neat PLACL, and also the crystallinity of composites increased. The functionalized MWCNTs have no significant effect on
the melting point of nanocomposites. The MWCNTs acted as heterogeneous nucleation points and increased the lamella size and
therefore the crystallinity of PLACL. Furthermore, the larger agglomerated clusters of both kinds of MWCNTs (i.e., MWCNT-grafted-PLACL
and pristine MWCNTs) are more effective than small clusters as nucleation points for growing the spherulites. 相似文献
59.
60.
The effect of air temperature (AT) and slice thickness (ST) on the quality and drying kinetics of tomato slices were studied. The drying period of tomato slices to reach the moisture content of 15% (wb) ranged from 2.6 to 18.7 h. The water diffusivity, activation energy, and resistance to diffusion ranged from 1.4 × 10?10 to 2.8 × 10?9 m2/s, 21.25 to 23.4 kJ/mol, and from 939 to 4590 m2 s/kg, respectively. Drying had a significant effect on ascorbic acid, soluble solid, acidity, and pH (P = 0.01). The ascorbic acid degradation was greatly influenced by ST. The results show that time-temperature superposition technique (TTST) was very efficient in the modeling of the drying process. The proposed TTST provides a novel alternative in curve-fitting exercise of drying data. Neural networks also showed favorable performance in estimating the drying functions. 相似文献