fatemeh mollaei

Today, the utilization of smart indicators in food packaging to monitor and detect food quality through analyzing quality data and color changes in packaging films based on the food's condition is on the rise. In this comparative study, halochromic films made of gelatin and k-carrageenan with mirabilis jalapa extract (6, 12, and 24%) and barberry extract (6, 12, and 24%) were developed and examined. Through SEM images and FTIR spectroscopy, it was observed that both types of films incorporating barberry and mirabilis jalapa extracts were uniformly dispersed in the gelatin and k-carrageenan polymer matrix, displaying notable molecular interactions like hydrogen bonding and electrostatic forces. However, films containing mirabilis jalapa extract exhibited more irregular and rough surfaces compared to those with barberry extract. Both types of films displayed good antioxidant properties and responsiveness to changes in pH and ammonia levels. Films with barberry extract demonstrated higher antioxidant activity and greater sensitivity to pH variations. The gelatin and k-carrageenan films with barberry and mirabilis jalapa extracts effectively indicated the freshness of lamb meat stored at 25°C by correlating with the presence of ammonia gases in the storage packages and pH fluctuations. Our results highlight that the structural, physical, and functional attributes of gelatin and k-carrageenan films incorporating pH-responsive extracts are significantly influenced by the extract type and concentration.

The current study aimed to evaluate the effect of an alginate coating containing peppermint essential oil (PEO) and solid lipid nanoparticles (SLNs) against Salmonella Typhimurium and Escherichia coli O157: H7 inoculated on beef fillets and subsequently stored at a temperature of 4 ± 1 °C for 12 days.

Beef fillet samples were divided into four groups: CON group (without any coating solution), ALG group (coated with alginate solution), ALG + PEO group (coated with alginate solution containing 0.1 % (w/v) PEO), and ALG + SLN-PEO group (with alginate solution in combination SLN containing 0.1 % (w/v) PEO). The samples were then analyzed for the presence of inoculated E. coli O157: H7 and S. Typhimurium during refrigerated storage.

The ALG + SLN-PEO coating had a larger impact in controlling the growth of pathogenic bacteria on beef fillets compared to the other treatment groups.

According to the obtained results, the ALG + SLN-PEO coating could potentially be used in the food industry to reduce the risks associated with contamination of beef fillets by E. coli O157: H7 and S. Typhimurium.

The present study aimed to determine the chemical composition and antibacterial activity of essential oil extracted from Ziziphora clinopodioide (ZCEO) in vitro. Furthermore, the study aimed to evaluate the effectiveness of chitosan nanoemulsion coating containing ZCEO and nisin in inhibiting the growth of Listeria monocytogenes inoculated on chicken breast fillets that were inoculated and vacuum-packaged, and stored at a temperature of 4±1 °C for 16 days.

The chemical composition and in vitro antibacterial activity of ZCEO were determined by gas chromatography-mass spectrometry (GC-MS) and microdilution method, respectively. The chicken breast fillet samples were divided into seven groups, namely, the control group (uncoated) without vacuum, control group with vacuum, chitosan nanoemulsion without vacuum, chitosan nanoemulsion with vacuum, chitosan nanoemulsion with 0.5% ZCEO and vacuum, chitosan nanoemulsion with nisin and vacuum, and chitosan nanoemulsion with 0.5% ZCEO, nisin, and vacuum. All the samples were stored in a refrigerator, and the population of L. monocytogenes was enumerated on days 0, 1, 2, 4, 8, 12, and 16.

the chemical analysis of ZCEO revealed that carvacrol, thymol, and p-cymene were the three main compounds present in the oil. Application of chitosan nanoemulsion coatings, specifically chitosan nanoemulsion + ZCEO 0.5% + vacuum and chitosan nanoemulsion + nisin + vacuum, resulted in a significant reduction in the growth rate of L. monocytogenes in chicken breast fillet samples during storage. In addition, the chitosan nanoemulsion coating containing the combined ZCEO and nisin was found to be more effective in reducing the growth of L. monocytogenes during the storage period.

Based on the results of this study, chitosan nanoemulsion + ZCEO 0.5% + nisin + vacuum coating can be used to reduce the risks that might be associated with L. monocytogenes in chicken breast fillets.

Smart ion-releasing restorative materials may increase the success and survival rate of composite dental restorations. This study aimed to evaluate the impact of sintering temperature on the mechanical properties and ion-releasing behavior of fluorohydroxyapatite (FHA)-filled dental resin composites. The FHA was synthesized via a sol-gel method and sintered at three temperatures (250, 500, and 1000ºC). FHA fillers were characterized using X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy, then coated with citric acid and incorporated (40% w/w) into a photo-curable resin matrix (Bis-GMA, TEGDMA, HEMA; weight ratio 2:1:1). Flexural strength (FS) and diametral tensile strength (DTS) were measured, as well as the depth of cure, which was determined by the Vickers microhardness test. The release of calcium and fluoride ions was monitored for a month in diluted citric acid (pH=4.3), and the effect of acidic storage on mechanical properties was evaluated via DTS testing. The filler distribution was observed via scanning electron microscopy. The influence of sintering temperature on the measured variables was statistically analyzed using one-way and two-way ANOVA (α=0.05). The XRD results revealed increased crystallinity with higher sintering temperatures. Correspondingly, mechanical properties improved with increasing sintering temperature (P<0.05), whereas the depth of cure, as well as ion release (Ca+2 and F-), decreased (P<0.05). Sintering at elevated temperatures yielded a greater amount of crystalline apatite structure, and enhanced mechanical properties of FHA-filled dental resin composites, but reduced ion release. Based on these findings, FHA fillers sintered at approximately 500ºC appear optimal for creating smart dental resin composite. (J Dent Mater Tech 2023;12(2):(82-90)

The aim of this research is to study the mediating rule of cognitive flexibility in the relationship of academic optimism and academic vitality.

For this purpose the descriptive correlation method has been used. The research population includes 4834 female second-grade secondary high school students of Zanjan in the academic year of 2018 and using the relative multi-stage cluster method, sample size was determined to be 400. In order to collect data, Dehghanizadeh and Husainichary’s academic vitality questionnaire (2012), Tschannen-Moran’s academic optimism questionnaire (2013) and Dennis and Vander wal’s cognitive flexibility questionnaire (2010) were used. Data analysis and structural equation analysis were performed using Pearson correlation, and Lisrel and SPSS 18 softwares, respectively.

The research findings indicate that the model is fitted and the research hypotheses, except for one case, are confirmed. The suggested model shows that academic optimism has an indirect (by mediation of cognitive flexibility) positive and meaningful relationship with academic vitality (p<0.01). Correlation analysis showed that there is a positive and meaningful relationship between academic optimism and academic vitality (p<0.05), while according to the model, such a result was not observed. The model also showed that there is a meaningful and positive relationship between academic optimism and cognitive flexibility, as well as between cognitive flexibility and academic vitality (p<0.05).

The findings highlight the role of academic optimism on cognitive flexibility, for arriving to academic vitality. The findings of the study were discussed regarding to theoretical and empirical evidence and suggestions have been made for this purpose.

Abstract The aim of this research is to study the mediating role of mindfulness in the relationship of academic engagement and academic vitality. For this purpose the descriptive correlation method has been used. The research population includes 4834 female second-grade secondary high school students of Zanjan in the academic year of 2017-18 and using the relative multi-stage cluster sampling, The sample size was determined to be 400. In order to collect data, Dehghanizadeh and Husainichary’s academic vitality questionnaire (1391), Fredricks, Blumenfeld and Paris’s academic engagement questionnaire (2004), Freiberk's Mindfulness questionnaire (2006), were used. Data analysis and structural equation analysis were performed using Pearson correlation, and Lisrel and SPSS 18 softwares, respectively.The research findings indicate that the model is fitted and the research hypotheses are confirmed.The results show that academic engagement, beside the positive and meaningful direct relationship with academic vitality=0/10 ,(p<0.05), has a positive and significant relationship with academic vitality with the mediation of mindfulness and cognitive flexibility (indirectly) = 0/094,(p<0.01).Due to the findings of the present work, in order to increase educational vitality of students, we suggest that educational psychologists and educational consultants codify a suitable educational plan and teach them the methods to improve educational engagement and mindfulness. Key words: Academic engagement, Academic vitality, Mindfulness, female student.

In this research, marketing research in Iran has been examined from a methodological point of view, and it seeks to answer the question of whether marketing research is suffering from the myopia in the methods? For this purpose, 1021 articles from 7 major and specialized journals in the field of commerce and marketing have been selected and their articles have been examined in terms of methodology and meta-method in a 10-year period (1387-1396). The results of this study showed that the researches carried out in Iran in the field of marketing have a very small variety of methodology, so that most of the articles were done using structural equation modeling method, with a quantitative tool and questionnaire.

According to the role of the customer in hospitality industry and importance of the provided quality of services, there is an increasing intense competition in the industry; hence, the recovery of failed services provides a second chance for companies to bolster their relationship with the customers, consequently, high performance of frontline employees affects behavioral intentions of customers. The aim of this study is proposing a service recovery model to illustrate how having high performance in the service recovery process causes tourists’ positive word-of-mouth. The statistical population of this study is composed of tourists who stayed in one of the 5-star hotels of Shiraz and were accessible during the research. Based on the Cochran formula 384 individuals have been considered as the statistical sample. The collected data have been analyzed using SPSS 22 and smart PLS 2 software. As the results show, high level of performance in service recovery influence tourists’ word of mouth.