241 research outputs found
Lead concentration in the muscles of slaughtered buffalos in northwest regions of Iran
Background: The topic of food safety has become a major public health issue worldwide. Over recent decades, the growing concern for food safety has brought about greater research regarding the risks associated with the consumption of produce that has been contaminated by pesticides, heavy metals and/or toxins.
Objective: The study was conducted to determine the concentration of Pb in the muscle of buffalos slaughtered in the northwest regions of Iran (Ardabil, Urmia and Tabriz cities).
Methods: The present was a descriptive cross-sectional study in the northwest regions of Iran during 2013 to 2014. A total of 30 muscle samples from individual buffalos were analyzed for Pb concentrations using Atomic Absorption Spectrophotometer (ASS). Statistical analysis was performed using SPSS 17.0. All results were computed as mean standard deviation and subjected to one-way analysis of variance to establish whether the differences in Pb concentrations in meat samples from different cities were significant or not. The Statistical significance was determined at p<0.05.
Results: The results showed that the mean concentration of Pb in muscle samples were measured 0.043±0.035 ppm. The highest Pb concentration (0.11 ppm) was detected in the buffalo muscle samples from Urmia city. In total, 25 muscle samples (80.33%) were contaminated with Pb and concentration of Pb in 3.33% of contaminated samples exceeded the permissible limits advised by the European Commission (EC) (0.1 ppm).
Conclusion: We recommend identifying Pb sources in order to eliminate or control Pb contamination of food, and monitor environmental exposures and hazards to prevent lead poisoning
Applications of Medicinal Herbs and Essential Oils in Food Safety
In the last few years, more and more studies on the biological properties of essential oils (EOs) especially antimicrobial and antioxidant properties in vitro and food model have been published in all parts of the world. But so far no comprehensive reports of these studies have been reported in food model from Iran. The focus of this overview lies in the using of EOs from some indigenous medicinal plants of Iran (including Mentha longifolia, Cuminum cyminum, Teucrium polium, Pimpinella anisum and Allium ascalonicum) in probiotic dairy products (especially cheese, yoghurt and Aryan) in recent years. Recently, consumers have developed an ever-increasing interest in natural products as alternatives for artificial additives or pharmacologically relevant agents. Among them, EOs have gained great popularity in the food, cosmetic as well as pharmaceutical industries. Despite the reportedly strong antimicrobial activity of EOs against food-borne pathogens and spoilage microorganisms, their practical application as preservatives is currently limited owing to the undesirable flavour changes they cause in food products. Nonetheless, more studies are necessary to the applicability of various EOs on other food models in Iran and other countries
Context-aware Mixture of Deep Neural Networks
Alpha-beta network is a mixture of deep neural networks, implementing a mixture of experts, where each component is a neural network. It is trained using the expectation-maximization algorithm. It enables context-awareness as each component is pushed to give context-specific predictions. Such structure enables context uncertainty quantification as well. The effectiveness of alpha-beta network was assessed using two real-world activity datasets: UCI OPPORTUNITY and an in-house dataset. The model has shown superior performance compared to the baselines
Field evaluation of a new particle concentrator- electrostatic precipitator system for measuring chemical and toxicological properties of particulate matter
<p>Abstract</p> <p>Background</p> <p>A newly designed electrostatic precipitator (ESP) in tandem with Versatile Aerosol Concentration Enrichment System (VACES) was developed by the University of Southern California to collect ambient aerosols on substrates appropriate for chemical and toxicological analysis. The laboratory evaluation of this sampler is described in a previous paper. The main objective of this study was to evaluate the performance of the new VACES-ESP system in the field by comparing the chemical characteristics of the PM collected in the ESP to those of reference samplers operating in parallel.</p> <p>Results</p> <p>The field campaign was carried out in the period from August, 2007 to March, 2008 in a typical urban environment near downtown Los Angeles. Each sampling set was restricted to 2–3 hours to minimize possible sampling artifacts in the ESP. The results showed that particle penetration increases and ozone concentration decreases with increasing sampling flow rate, with highest particle penetration observed between 100 nm and 300 nm. A reference filter sampler was deployed in parallel to the ESP to collect concentration-enriched aerosols, and a MOUDI sampler was used to collect ambient aerosols. Chemical analysis results showed very good agreement between the ESP and MOUDI samplers in the concentrations of trace elements and inorganic ions. The overall organic compound content of PM collected by the ESP, including polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, and alkanes, was in good agreement with that of the reference sampler, with an average ESP -to -reference concentration ratio of 1.07 (± 0.38). While majority of organic compound ratios were close to 1, some of the semi-volatile organic species had slightly deviated ratios from 1, indicating the possibility of some sampling artifacts in the ESP due to reactions of PM with ozone and radicals generated from corona discharge, although positive and negative sampling artifacts in the reference filter sampler cannot be ruled out.</p> <p>Conclusion</p> <p>The very good overall agreement between ESP and reference samplers makes it an attractive alternative to filters and biosamplers for chemical and toxicological evaluation of PM properties, including the possibility of conducting direct in vitro cell exposures. Moreover, the concentration enrichment of ambient aerosols by the VACES allows for short-term exposure studies, which preserve cell viability and enable studies to PM generated from specific sources and-or formation mechanisms in the atmosphere.</p
Effect of Packaging Material on Color Properties of Catsup Tomato Sauce
Catsup and tomato sauce products currently are one of the most popular and commercially available table sauces particularly consumed by young people and families around the world in recent decades. In this study colorimetric properties of catsup sauce samples including L*, a* and b* values in different packaging materials including PP, PE, PET, Glass and Sachet have been investigated during and after 180 days storage time at 22̊ C (environmental temperature). Hunter Lab system has been used to evaluate the color values of sauce samples. According to obtained results of experimental measurements and sensory evaluations, PP and PE packaging materials affected significantly color properties of catsup sauce samples during and after the storage time that it because of interaction between packaging material and lycopene components in catsup sauce samples. Finally, According to consumer prefers to darker tomato and catsup sauce products, PP and PE are not suitable for packaging of catsup sauce production
BoXHED2.0: Scalable boosting of dynamic survival analysis
Modern applications of survival analysis increasingly involve time-dependent
covariates. In healthcare settings, such covariates provide dynamic patient
histories that can be used to assess health risks in realtime by tracking the
hazard function. Hazard learning is thus particularly useful in healthcare
analytics, and the open-source package BoXHED 1.0 provides the first
implementation of a gradient boosted hazard estimator that is fully
nonparametric. This paper introduces BoXHED 2.0, a quantum leap over BoXHED 1.0
in several ways. Crucially, BoXHED 2.0 can deal with survival data that goes
far beyond right-censoring and it also supports recurring events. To our
knowledge, this is the only nonparametric machine learning implementation that
is able to do so. Another major improvement is that BoXHED 2.0 is orders of
magnitude more scalable, due in part to a novel data preprocessing step that
sidesteps the need for explicit quadrature when dealing with time-dependent
covariates. BoXHED 2.0 supports the use of GPUs and multicore CPUs, and is
available from GitHub: www.github.com/BoXHED.Comment: 12 page
طراحی و بهینه سازی روش ردیابی و تشخیص مستقیم��استافیلوکوکوس اورئوس در مواد غذایی با استفاده ازروش��SYBR green melting curve Real time PCR(فایل تصویب عنوان)
Antibiotic Resistance and Molecular Characterization of Cronobacter sakazakii Strains Isolated from Powdered Infant Formula Milk
Background: Cronobacter sakazakii is a new emerging foodborne bacterial pathogen associated with severe lethal diseases such as meningitis, necrotizing enterocolitis, and septicemia in infants and neonates. Powdered infant formula milk (PIFM) has been recognized as one of the main transmission vehicles and contaminated sources of this pathogen. This study aimed to investigate the prevalence rate, genotypic and phenotypic antibiotic resistance profile, and clonal relatedness of C. sakazakii strains isolated from 364 PIFM samples collected from Tehran city, Iran. Methods: Culture-based methods, Kirby–Bauer disk diffusion antibiotic resistance testing, conventional Polymerase Chain Reaction (PCR), and Enterobacterial Repetitive Intergenic Consensus PCR (ERIC-PCR) assays were used in this study to detect and characterize the C. sakazakii isolates. Results: We isolated 25 C. sakazakii strains from PIFM samples (6.86%). The isolates were highly resistant to amoxicillin-clavulanic acid, amoxicillin, ampicillin, cefoxitin, cefepime, erythromycin, ceftriaxone, ciprofloxacin, and chloramphenicol and susceptible to gentamicin, tetracycline, norfloxacin, and azithromycin antibiotics. The blaCTX-M-1 gene was detected in 96% of the isolates. The isolates were categorized into eight distinct clonal types using the ERIC-PCR method, showing a high genetic diversity among the isolates. However, there was a significant correlation between the genotypic and phenotypic antibiotic resistance properties of the isolates. Conclusions: Novel microbial surveillance systems for detecting multi-drug-resistant C. sakazakii are required to control the contamination of this foodborne pathogen in infant foods
Near Points of Convergence and Accommodation in a Population of University Students in Iran
Purpose: To determine the distribution of the near point of convergence (NPC) and near point of accommodation (NPA) in a young student population in Iran.
Methods: The subjects were selected using a cluster sampling method. All students underwent optometry tests, including visual acuity measurement, refraction, and cover test, as well as ophthalmic examinations. The NPC and NPA were measured using an accommodative target (near Snellen chart).
Results: Of 1,595 students, the data of 1,357 were analyzed. The mean NPC and NPA in the total sample were 7.25 cm (95% confidence interval [CI], 7.02 to 7.48) and 9.99 cm (95% CI, 9.69 to 10.29), respectively. Older age was associated with an increase in the NPC, which increased from 6.98 cm in 18–20 years olds to 9.51 cm in those over 30 years. The NPA was significantly associated with age and refractive errors in the multiple linear regression model, increasing from 9.92 cm in 18–20 years olds to 11.44 cm in those over 30 years (P = 0.003). Hyperopic eyes had lower NPA than myopic and emmetropic eyes (P = 0.001). In younger age groups, the mean accommodation amplitude was lower than the mean Hofstetter value. Moreover, with age, especially after 30 years, the mean values surpassed those determined using the Hofstetter formula.
Conclusion: The NPC values in this study were lower than those previously reported for identical age groups. The Hofstetter formula is not always an accurate predictor of the accommodation amplitude in the Iranian adult population
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