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排序方式: 共有315条查询结果,搜索用时 31 毫秒
251.
Antonios E. Goulas Elisavet Salpea Michael G. Kontominas 《European Food Research and Technology》2008,226(4):915-923
Polyvinyl chloride (PVC) film containing di(2-ethylhexyl) adipate (DEHA) plasticizer was used to wrap sea bream (Sparus aurata) and rainbow trout (Oncorhynchus mykiss) fillet samples with and without skin. After wrapping the samples were stored at 2 ± 0.5 °C and analyzed for DEHA content
at time intervals between 5 and 360 h of contact (kinetic study). Determination of DEHA was performed using a direct gas chromatography
(GC) method. Statistically significant differences (p < 0.05) in migration of DEHA were observed between the two fish fillet samples: the mean equilibrium migration amount of
DEHA in sea bream was 2.93 mg/dm2 film (91.9 mg/kg fillet) corresponding to a loss of 19.0% (w/w) DEHA from PVC film; while the mean equilibrium amount of
DEHA in rainbow trout was 3.74 mg/dm2 (117.6 mg/kg) corresponding to a loss of 23.9% (w/w) DEHA. The above values for DEHA in sea bream are very close to the limit
of 3 mg/dm2 of film surface set by the EU for DEHA while the corresponding migration values for rainbow trout exceeded this limit. Diffusion
coefficients for DEHA in the PVC film during contact with both fish fillets were calculated and found significantly different
between two fish samples. Furthermore, the presence of skin on the fillet decreased migration of DEHA into the fish flesh
by a factor of 2.4–2.8. Based on equilibrium migration values of DEHA it is concluded that for a 60-kg adult, a daily consumption
of 150 g rainbow trout or 200 g sea bream fillet packaged in PVC film would result in a daily intake of DEHA close to the
tolerable daily intake (TDI) of 0.3 mg/kg body weight set by the EU. 相似文献
252.
Leonid Farber Michel W. Barsoum Antonios Zavaliangos Tamer El-Raghy Igor Levin 《Journal of the American Ceramic Society》1998,81(6):1677-1681
The ternary carbide Ti3 SIC2 fabricated by a reactive hot-press route is investigated by transmission electron microscopy. The material consists mainly of large elongated grains with planar boundaries, and is characterized by a low defect density. Dislocations are observed in the grains and at grain boundaries. Perfect dislocations with b = 1/3<1120> lying in (0001) basal planes are present. These basal plane dislocations are mobile and multiply as a result of room-temperature deformation. All of the stacking faults observed lie in the basal planes. 相似文献
253.
Overall migration from commercial coextruded food packaging multilayer films and plastics containers into official EU food simulants 总被引:1,自引:0,他引:1
Antonios E. Goulas 《European Food Research and Technology》2001,212(5):597-602
The overall migration from a wide range of commercial five-layer coextruded packaging films into aqueous food simulants (distilled water, 3% aqueous acetic acid) and alternative fatty food simulant (iso-octane) was studied. The overall migration from commercial plastics cups (PS, HIPS, and PP) used for ice-cream or yogurt packaging into distilled water and 3% aqueous acetic acid was also studied. Test conditions for packaging material/food simulant contact and method of overall migration analysis were according to the EU directives and CEN-standards. The results showed that for all tested five-layer films and plastics (PS, HIPS, and PP) cups values of overall migration into aqueous simulants (0.11-0.79 mg/dm2, 2.3-15.9 mg/l) and (<0.10-0.41 mg/dm2, <0.80-3.1 mg/l) were significantly lower than the upper limit (10 mg/dm2) for overall migration from plastic packaging materials and articles into food and food simulants set by the EU Directive 90/128/EEC and their revisions. The overall migration values from five-layer materials into iso-octane were significantly higher (0.94-8.23 mg/dm2, 18.8-164.7 mg/l) than the above values but are still lower than the upper limit for overall migration. Global migration values of five-layer films into aqueous food simulants seems to be independent of material thickness. In contrast, overall migration into iso-octane increases with film thickness. 相似文献
254.
Christina Papachristou Anastasia Badeka Eirini Chouliara Efthymia Kondyli Antonios Athanasoulas Michael G. Kontominas 《European Food Research and Technology》2006,223(6):711-718
Chemical, microbiological, and sensorial changes in premium quality whole pasteurized milk stored at 4 °C under fluorescent light for one day followed by storage in the dark for an additional 12 days was studied. Milk containers tested included 1 l bottles made of (a) clear PET + UV blocker, 350–400μm in thickness bearing a transparent label, (b) clear PET + UV blocker, 350–400 μm in thickness bearing a white colored label, (c) clear PET 350–400 μm in thickness. Milk packaged in 1 l coated paperboard cartons and stored under the same experimental conditions served as the “commercial control” sample. Data were obtained for lipid oxidation, lipolysis, proteolysis, vitamin A, E, and riboflavin content, microbial growth including mesophilic and psychrotrophic counts and sensorial attributes (odor and taste) of whole pasteurized milk. Results showed satisfactory protection of milk packaged in all containers with regard to microbiological and chemical parameters assessed over the 13 day period. Based on sensory analysis, the shelf life of premium quality whole pasteurized milk tested in the present study was 10–11 days for samples packaged in clear PET+UV bottles and 9–10 days for clear PET bottles and paperboard cartons. Vitamin A losses recorded after 10 days of storage were respectively 15.9, 20.6, and 14.3% for samples packaged in clear PET+UV protected bottles, clear PET, and control samples. Respective losses for Vitamin E were 26.4, 36.6, and 35.0% and for riboflavin 32.9, 38.3, and 32.5%. Clear PET + UV provided equal or better protection to milk as compared to the paperboard carton. Clear PET was the least effective in retaining light-sensitive vitamins. Based on spectral transmission curves of packaging materials tested, it is suggested that the use of a UV blocking agent in combination with a dark color pigmentation (blue, green etc.) in fresh milk packaging will provide a better protection to light-sensitive vitamins in cases where the expected shelf life of milk exceeds 5–6 days. 相似文献
255.
Konstantina Alexaki Davide Giust Maria-Eleni Kyriazi Afaf H. El-Sagheer Tom Brown Otto L. Muskens Antonios G. Kanaras 《Frontiers of Chemical Science and Engineering》2021,15(4):935-943
We demonstrate the fabrication of a new DNA sensor that is based on the optical interactions occurring between oligonucleotide-coated NaYF4: Yb3+; Er3+ upconversion nanoparticles and the two-dimensional dichalcogenide materials, MoS2 and WS2. Monodisperse upconversion nanoparticles were functionalized with single-stranded DNA endowing the nanoparticles with the ability to interact with the surface of the two-dimensional materials via van der Waals interactions leading to subsequent quenching of the upconversion fluorescence. By contrast, in the presence of a complementary oligonucleotide target and the formation of double-stranded DNA, the upconversion nanoparticles could not interact with MoS2 and WS2, thus retaining their inherent fluorescence properties. Utilizing this sensor we were able to detect target oligonucleotides with high sensitivity and specificity whilst reaching a concentration detection limit as low as 5 mol·L–1, within minutes. 相似文献
256.
Dimitra Papadopoulou Antonios Drakopoulos Panagiotis Lagarias Georgia Melagraki George Kollias Antreas Afantitis 《International journal of molecular sciences》2021,22(19)
Tumor necrosis factor (TNF) is a regulator of several chronic inflammatory diseases, such as rheumatoid arthritis. Although anti-TNF biologics have been used in clinic, they render several drawbacks, such as patients’ progressive immunodeficiency and loss of response, high cost, and intravenous administration. In order to find new potential anti-TNF small molecule inhibitors, we employed an in silico approach, aiming to find natural products, analogs of Ampelopsin H, a compound that blocks the formation of TNF active trimer. Two out of nine commercially available compounds tested, Nepalensinol B and Miyabenol A, efficiently reduced TNF-induced cytotoxicity in L929 cells and production of chemokines in mice joints’ synovial fibroblasts, while Nepalensinol B also abolished TNF-TNFR1 binding in non-toxic concentrations. The binding mode of the compounds was further investigated by molecular dynamics and free energy calculation studies, using and advancing the Enalos Asclepios pipeline. Conclusively, we propose that Nepalensinol B, characterized by the lowest free energy of binding and by a higher number of hydrogen bonds with TNF, qualifies as a potential lead compound for TNF inhibitors’ drug development. Finally, the upgraded Enalos Asclepios pipeline can be used for improved identification of new therapeutics against TNF-mediated chronic inflammatory diseases, providing state-of-the-art insight on their binding mode. 相似文献
257.
The thrust generation by electro-hydrodynamic (EHD) effect has been studied for a wire-cylinder arrangement under high DC voltage. Series of measurements have been conducted in order to determine the relationship between generated thrust and corona discharge current, as well as its dependence on geometrical characteristics of the electrodes, e.g. electrode gap, wire and cylinder radii. The experimental investigation has shown a linear relationship between the generated thrust and the discharge current, while parametric analysis showed that increased electrode gap and emitter radius reduces the thrust. On the other hand, large gaps favor the thrust per unit power ratio. 相似文献
258.
Super‐tough biodegradable poly(vinyl alcohol)/poly(vinyl pyrrolidone) blends plasticized by glycerol and sorbitol
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Phetdaphat Boonsuk Kaewta Kaewtatip Sirinya Chantarak Antonios Kelarakis Chiraphon Chaibundit 《应用聚合物科学杂志》2018,135(26)
Tough biodegradable films were prepared using a poly(vinyl alcohol) (PVA)/poly(vinyl pyrrolidone) (PVP) (1:1) blend with plasticizers of glycerol (GLY), sorbitol (SOR), and their (one to one) mixture. We studied the effect of plasticization on the structural, thermal, and mechanical properties of the PVA/PVP blend films. Fourier transform infrared spectra indicated good miscibility of the two components due to the H‐bonding between the PVA and PVP molecules. The addition of plasticizers reduced the interaction between PVA and PVP, evidenced by an increase in the intensity of PVA diffraction peaks observed in the X‐ray diffraction (XRD) characterization. Thermal degradation of the blends increased as a function of the plasticizer used. GLY affected thermal degradation more than SOR and the mixtures. The incorporation of the plasticizers promoted the growth of PVA crystals as evidenced by XRD patterns and the enthalpy of fusion (ΔHf) obtained by differential scanning calorimetry measurements. The introduction of SOR to the binary blend increased toughness seven times and imparted simultaneous and pronounced improvements to maximum tensile stress and elongation at break. This behavior holds out great promise for the development of a new generation of mechanically robust, yet thoroughly biodegradable materials that could effectively supplant conventional polymers in demanding applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46406. 相似文献
259.
Antonios G. MarinopoulosAuthor Vitae Minas C. AlexiadisAuthor VitaePetros S. DokopoulosAuthor Vitae 《Electric Power Systems Research》2011,81(10):1986-1994
This paper proposes a methodology for stochastic power flow in a distribution line with dispersed photovoltaic (PV) penetration. Both load and PV generation are stochastic processes. The methodology uses a probabilistic model for load demand based on measured data and an extensive stochastic modeling of PV units’ power production based on historical meteorological data and commercial available PV panels. Annual power flow simulations are performed to evaluate loss reduction resulting for different penetration levels and siting strategies of PV into an urban radial distribution feeder. Finally, a cost index for the losses is defined taking into account System Marginal Price data. Results may be of interest for dimensioning, siting and cost allocation in distribution systems with dispersed generation. 相似文献
260.
Antonios Lazaridis Eleni Gavriilaki Stella Douma Eugenia Gkaliagkousi 《International journal of molecular sciences》2021,22(7)
Essential hypertension (EH) is a highly heterogenous disease with a complex etiology. Recent evidence highlights the significant contribution of subclinical inflammation, triggered and sustained by excessive innate immune system activation in the pathogenesis of the disease. Toll-like receptors (TLRs) have been implied as novel effectors in this inflammatory environment since they can significantly stimulate the production of pro-inflammatory cytokines, the migration and proliferation of smooth muscle cells and the generation of reactive oxygen species (ROS), facilitating a low-intensity inflammatory background that is evident from the very early stages of hypertension. Furthermore, the net result of their activation is oxidative stress, endothelial dysfunction, vascular remodeling, and finally, vascular target organ damage, which forms the pathogenetic basis of EH. Importantly, evidence of augmented TLR expression and activation in hypertension has been documented not only in immune but also in several non-immune cells located in the central nervous system, the kidneys, and the vasculature which form the pathogenetic core systems operating in hypertensive disease. In this review, we will try to highlight the contribution of innate immunity in the pathogenesis of hypertension by clarifying the deleterious role of TLR signaling in promoting inflammation and facilitating hypertensive vascular damage. 相似文献