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851.
The effect of storage temperature (0–40 °C) and inoculum size (101–105 spores) on the mycelium growth kinetics of 12 fungal species on yogurt were monitored. A cardinal model with inflection (CMI) was used to describe the effect of temperature on the growth rate (μ) and the lag time (λ) of each isolate. Significant differences on the temperature dependence of the mycelium growth between the tested species were observed. Depending on the strain, the estimated minimum, optimum and maximum temperature parameters for μ (Tmin, Topt, Tmax) ranged from −7.6 to 9.6, 19.5 to 37.8 and 29.8 to 46.9 °C, respectively. Only λ was found to be affected by the inoculum size and a linear relation between Ln (λ) and Log (inoculum size) was revealed. The inoculum level did not influence the values of Tmin, Topt and Tmax for λ. Based on the above observations, the combined effect of inoculum size and temperature on λ was modeled using a modified CMI. The parameter λopt (λ at optimum conditions) was expressed as a function of the inoculum size. Validation studies showed a good performance of the developed models. The application scheme of the models for improving fungi control in yogurt productions is discussed. 相似文献
852.
Pappas AC Zoidis E Georgiou CA Demiris N Surai PF Fegeros K 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2011,28(4):446-454
The aim of the study was to investigate the interactions between selenium (Se) and various trace elements, both toxic and essential, involved in the antioxidant system. A total of 128 day-old chicks (Gallus gallus, broilers) were used to investigate the effect of Se yeast supplementation on the accumulation of cadmium (Cd), copper (Cu) iron (Fe) and zinc (Zn). There were four replicates of four dietary treatments: T1 (basal diet with no added Se, analyzed to contain 0.21 mg kg(-1)), T2 (T1 with 0.15 mg kg(-1) Se added), T3 (T1 with 0.3 mg kg(-1) Se) and T4 (T1 with 3.0 mg kg(-1) Se). At week 4 and 6, two chickens per replicate pen were sacrificed for whole blood, breast muscle and liver sampling. Samples were analyzed by ICP-MS. Supplementation with Se-yeast, not only increased Se concentration but also reduced Cd concentration in the tissues. Selenium was negatively correlated with Cd and positively correlated with Zn, Cu and Fe. Cadmium was negatively correlated with Zn and Cu. Zinc was positively correlated with Cu. Iron was negatively correlated with Cu and uncorrelated with Zn and Cd. The balance between Se, Cu, Fe and Zn is important for proper antioxidant defense since they are an integral part of various antioxidant enzymes. 相似文献
853.
Xilin Chen Konstantinos Gerasopoulos Juchen Guo Adam Brown Reza Ghodssi James N. Culver Chunsheng Wang 《Electrochimica acta》2011,(14):4512
A patterned 3D Si anode is fabricated by physical vapor deposition of n-type Si on a self-assembled TMV1cys-structured nickel current collector. The combination of the large surface area conferred by the virus-enabled 3D Ni/TMV1cys current collector with the high electric conductivity of n-type Si rods results in excellent cyclic stability and rate capability for the core-shell n-type Si/Ni/TMV1cys anodes. Electrochemical impedance spectroscopy reveals that the high electronic conductivity of n-type Si significantly reduces charge transfer resistance, thus even at high current densities the capacity of the n-type Si is increased to almost 630 mAh/g compared to undoped Si. 相似文献
854.
Konstantinos Dimitriadis Dimitrios Moschovas Simeon Agathopoulos 《International Journal of Applied Ceramic Technology》2023,20(1):350-359
The present in vitro study aims at characterizing dental zirconia ceramics, which are stabilized with a high amount of Y2O3. Two groups of specimens were fabricated by computer-aided design/computer-aided manufacturing technique. The specimens of each group were divided into two subgroups (SGs): SGs 1a and 2a contained a relatively low amount of Y2O3 (6–8 wt.%), whereas SGs 1b and 2b contained a higher amount of Y2O3 (8–10 wt.%). The influence of yttria content on their microstructure and mechanical properties was experimentally determined. The statistical significance of the differences in the mechanical properties between the SGs was evaluated by the t-test (p < 5% was considered statistically significant). Homogeneous and dense ceramics with fine nanostructure, comprising grains of yttria-stabilized tetragonal and cubic zirconia, sized between ∼160 and ∼800 nm, were produced. The increase of yttria content, which causes an increase in grain size, favors the formation of cubic zirconia, resulting in mechanical properties’ slight reduction; yet, the differences were not statistically significant. Consequently, the mechanical properties (HV 11.74–12.91 GPa, and KIC 2.66–4.25 MPa m0.5) and the good esthetics of the investigated zirconia ceramics stabilized with high yttria content qualify these zirconia materials for fabricating dental restorations, because they can approach the properties and the esthetics of dental hard tissues as well as the tooth structure. 相似文献
855.
We report a new concept for capacitive deionization with simple and cheap porous bipolar intermediate graphite electrodes which is operated continuously by constant or alternating polarity without any down time for electrode saturation, regeneration and rinsing steps and certainly without any permselective ion exchange membranes. The proposed process utilizes the advantages of the classical electrodeionization technologies combining them all to a unified continuous capacitive deionization-continuous electrodeionization-electrodialysis-electrodialysis reversal process. Separate and unchanged diluate and concentrate compartments are created in two modes, first by periodical charging/discharging the bipolar intermediate electrodes through a pulsating electric field and second by simultaneous charging/discharging them through a constant or pulsating electric field and electrostatic shielding. Because of coion permeation and the convenience of alternating the polarity without any negative impact on the deionization process, the new technique is less affected by the known membrane associated limitation, such as concentration polarization, limiting current density or scaling. The new electrochemical deionization technique is suitable for regeneration of ion exchange resins and production of high purity deionized water, removal of heavy metal ions from industrial effluents and desalination of brackish or seawater. 相似文献
856.
Sofia Anastasios Papadimitriou Dimitrios Bikiaris Konstantinos Avgoustakis 《应用聚合物科学杂志》2008,108(2):1249-1258
In this study, solid dispersions of poorly water‐soluble Tibolone in a poly(ethylene glycol) matrix were prepared with conventional melt mixing and microwave irradiation. The results of the assay content, LC–MS, and 1H‐NMR indicated that microwave irradiation did not affect drug stability when a relatively low irradiation power (440 W) was used. Fourier transform infrared spectroscopy indicated that there were no hydrogen bonds formed between Tibolone and poly(ethylene glycol), and this affected the drug's crystallinity and its particle size distribution. The dissolution rate of the drug was slightly higher in the case of dispersions prepared by microwave irradiation. This enhancement of the drug dissolution rate was probably due to the lower size of the Tibolone particles in the dispersions prepared by microwave irradiation. The application of microwaves represents a promising alternative to conventional preparative methods of drug dispersions. The main advantage in comparison with conventional melt mixing is that solid dispersions can be prepared in much shorter times. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
857.
Konstantinos Salonitis 《CIRP Annals》2014,63(1):189-192
Modular design can address the need for a high number of product variants and further allow a higher degree of automation in the assembly line. A framework is developed for the simultaneous modular product design and the design of automated manufacturing system. Product designs are optimized for automation using Design Structure Matrix and Modular Function Deployment. Alternative production systems are designed and accessed based on the analysis of assembly steps hierarchically. The implementation of the framework on the design of a production system for furniture assembly, able to handle multiple variants with a large number of components, is demonstrated. 相似文献
858.
Konstantinos Tsioris Waseem K. Raja Eleanor M. Pritchard Bruce Panilaitis David L. Kaplan Fiorenzo G. Omenetto 《Advanced functional materials》2012,22(2):330-335
Microneedles are emerging as a minimally invasive drug delivery alternative to hypodermic needles. Current material systems utilized in microneedles impose constraints hindering the further development of this technology. In particular, it is difficult to preserve sensitive biochemical compounds (such as pharmaceuticals) during processing in a single microneedle system and subsequently achieve their controlled release. A possible solution involves fabricating microneedles systems from the biomaterial silk fibroin. Silk fibroin combines excellent mechanical properties, biocompatibility, biodegradability, benign processing conditions, and the ability to preserve and maintain the activity of biological compounds entrained in its material matrix. The degradation rate of silk fibroin and the diffusion rate of the entrained molecules can be controlled simply by adjusting post‐processing conditions. This combination of properties makes silk an ideal choice to improve on existing issues associated with other microneedle‐based drug delivery system. In this study, a fabrication method to produce silk biopolymer microstructures with the high aspect ratios and mechanical properties required to manufacture microneedle systems is reported. Room temperature and aqueous‐based micromolding allows for the bulk loading of these microneedles with labile drugs. The drug release rate is decreased 5.6‐fold by adjusting the post‐processing conditions of the microneedles, mainly by controlling the silk protein secondary structure. The release kinetics are quantified in an in vitro collagen hydrogel model, which allows tracking of the model drug. Antibiotic loaded silk microneedles are manufactured and used to demonstrate a 10‐fold reduction of bacterial density after their application. The processing strategies developed in this study can be expanded to other silk‐based structural formats for drug delivery and biologicals storage applications. 相似文献
859.
860.
Zoumpopoulou G Papadimitriou K Polissiou MG Tarantilis PA Tsakalidou E 《International journal of food microbiology》2010,144(1):202-207
It was previously established that Lactobacillus fermentum ACA-DC 179, Lactobacillus plantarum ACA-DC 287 and Lactobacillus plantarum ACA-DC 2350 exhibit antimicrobial activity against Salmonella enterica serovar Typhimurium. In order to further investigate the killing effect of these microorganisms against Salmonella cells, we employed Fourier transform infrared spectroscopy (FT-IR). Salmonella cells were incubated with different concentrated lactobacilli supernatants and their FT-IR spectra were recorded. The second derivative transformation of the original spectra revealed changes in spectral regions corresponding to absorptions of major cellular constituents (e.g. cell wall, cell membrane, and proteins of the cell) among the Salmonella cells treated with the supernatants and those treated with the control samples. Principal component analysis of the second derivative transformed spectra showed that the yet unidentified antimicrobial compound(s) produced by the lactobacilli tested clearly interfered with the fatty acids of the cell membrane, as well as the polysaccharides of the cell wall in Salmonella cells, pointing towards a dual killing mode. Our study shed light for the first time in the anti-Salmonella activity of the particular Lactobacillus strains. 相似文献