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Showing 4 results for خندقی


Volume 3, Issue 1 (Winter 2023)
Abstract

Defining beauty is one of the most critical issues in philosophical aesthetics. Walking philosophers have brought or referred to the concept of "perfection" as one of the main elements of the definition of beauty. After explaining the views of Avicenna and Aquinas in this field, this research deals with the question of what is the place of the concept of perfection in the definition of the beauty of both of them. This research is descriptive-analytical. In the collection, it uses the library method, and in the analysis, it uses the qualitative method. The results of this research show that beauty is essential in the view of both philosophers about tangibles and abstractions. From Avicenna's perspective, the perfection of the senses should have three aesthetic elements: good order, good composition (composition), and good moderation. Aquinas also uses the concepts of pleasure, proportion, and clarity in his definitions. These elements in the definitions of beauty can be evaluated in some way in connection with the idea of the second perfection.
 

Volume 18, Issue 113 (july 2021)
Abstract

Excessive use of antibiotics in the production of livestock has led to the accumulation of antibiotic residues in various livestock products such as meat and milk. Consumption of foods containing antibiotics leads to problems such as increased antibiotic resistance, while their accumulation in the body can lead to mutagenesis and cancers, liver damage and abortion. For this reason, monitoring residual antibiotics, especially in high-consumption and beneficial food products such as milk and dairy products, is of particular importance. In this research, a dispersive solid-phase micro-extraction method for the extraction of tetracycline, oxytetracycline, chlortetracycline and doxycycline antibiotics from 50 milk samples and their quantitative measurement by HPLC was developed. For this purpose, the effect of various parameters affecting the extraction efficiency such as the volume of the precipitating agent, the type and amount of solid adsorbent, ionic strength, aeration time and flow rate, type and amount of surfactant and type and volume of elution solvent were optimized. The results showed that all milk samples contained tetracycline residue and its concentration varied in the range of 146 to 319 ng / ml. No other antibiotics were found in the samples. The advantages of the proposed extraction method include high separation power and the possibility of analyzing a mixture of highly sensitive analytes, so that under optimal conditions, recoveries of the proposed method ranging from 80 to 91%, the LOD were in the range of 0.17-0.33 ng / ml and the linear range was in the range of 0.63-2000 ng / ml.

Volume 20, Issue 139 (September 2023)
Abstract

Excessive use of antibiotics in the animal husbandry causes the accumulation of their residual amounts in food of animal origin such as dairy products. Since the consumption of these foods has a negative effect on human health, authorized organizations such as the European :union: have set maximum residue limits (MRLs) for antibiotics in food of animal origin. This research aimed to present a magnetic ionic solvent based extraction procedure for preparation and preconcentration of tetracycline, oxytetracycline and enrofloxacin residues in cheese samples and their determination by high-performance liquid chromatography equipped with a diode array detector. For this, the effect of various parameters on the extraction efficiency was investigated and optimized. The results showed that the residual amounts of oxytetracycline and tetracycline in 4 and 5 samples of the tested cheeses, respectively, were determined above the permissible limits. Enrofloxacin residue was not found in any of the samples. From the advantages of the proposed extraction method, we can point out the high separation power and the possibility of highly sensitive analyzing of mixed analytes, so that under optimized conditions, the recovery percentage ranges were 80-91. The limits of detection and quantification were respectively less than 1.8 and 6 ng/g, which is much lower than the MRLs set for target antibiotics in cheese (100 ng/g).

Volume 22, Issue 158 (April 2025)
Abstract

The main reason for the presence of specific microbiota, particularly lactic acid bacteria in dairy products made from raw milk, such as Lighvan cheese, is the traditional methods of preparing these products. A large number of these bacteria are probiotic microorganisms, and for example, many species of Lactobacillus, Enterococcus and Pediococcus bacteria presented in foods have shown probiotic properties. In the current study, genus-specific PCR detection for the Lactobacillus, Enterococcus, and Pediococcus genera was used to confirm the isolates of lactic acid bacteria that had been phenotypically isolated from 25 samples of traditional Lighvan cheese. Subsequently, the probiotic properties of the isolates, including resistance in simulated gastrointestinal tract conditions, antagonistic properties, auto-aggregation and co-aggregation attributes, antibiotic resistance and hemolytic activities of the selected strains were evaluated. Based on biochemical and molecular detection tests, among the 84 selected strains, 58 isolates were identified as Lactobacillus (29 isolates), Enterococcus (18 isolates) and Pediococcus (11 isolates). Screening of these isolates for survival in human GI tract conditions showed that 26.1% of the isolates (14 isolates) had resistance levels above 50%. Also, nine isolates of the selected strains showed potent antibacterial activity against Listeria monocytogenes and Staphylococcus aureus, as well as Aspergillus flavus and Penicillium citrinum molds. Moreover, based on the ability of auto-aggregation and co-aggregation features, four isolates LS106, LS71, LS33 and LS6 (belonging to Lactobacillus and Enterococcus genera) were selected. Finally, the investigation of antibiotic resistance revealed the sensitivity of these isolates to majority of the used antibiotics, so that all isolates were susceptible to tetracycline and ampicillin. Also, not one of these four isolates exhibited hemolytic properties. As a result, these isolates are recommended as suitable candidates for usage in fermented food products, taking advantage of their beneficial properties.

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