Evaluation of surface characteristics of denture base using organic-inorganic hybrid coating: an SEM study

Statement of Problem: Despite the numerous positive features of acrylic denture base, there are a number of undeniable associated disadvantages. The properties of denture base have been improved through various interventions including application of different types of filler and coatings

Objectives: This study aimed to evaluate the surface roughness, thickness and coating quality of organic-inorganic coating on the denture base through scanning electron microscopy. Moreover, the colour change was evaluated visually

Materials and Methods: The organic-inorganic hybrid coatings were prepared. Acrylic discs of 10x10 mm were fabricated. The test discs were dipped in the hybrid coating and cured. In order to evaluate the surface roughness and coating thickness, the surface and cross-section of the samples in both coated and control groups were subjected to scanning electron microscopy. The colour change and transparency were visually evaluated with naked eyes. The data were statistically analyzed by student's t test

Results: The hybrid materials perfectly covered all the surfaces of acrylic resin and established proper thickness. The coated group seemed smoother and flatter than the control group; however, the difference was not statistically significant [for all parameters p > 0.05]. It was quite a thin coating and no perceptible colour change was observed

Conclusions: The hybrid coating maintained good binding, caused no noticeable discoloration, and thoroughly covered the acrylic resin surface with uniform delicate thickness. It also slightly improved the acrylic resin surface roughness

rate of airborne fungal contamination in Yazd textile factories in 2007

Fungi are among the most important biological agents in air pollution. Textile factories are known as high risk places for contamination with fungal spores and metabolites. Since Yazd is one of the most important textile industry centers, this study was conducted to determine the concentration and types of airborne fungi in Yazd textile factories. A total of 235 indoor air samples from 30 randomly selected Yazd textile factories in 2007 were collected using air sampler pumps with appropriate filters. The concentration and types of isolated fungi were determined according to NIOSH standard technique for isolation of biologic agents. Data were analyzed based on the survey objectives, using statistical tests. Overall, 958 colonies from 16 different genera of fungi were isolated and among them Penicillium, Aspergillus and Cladosporium were known as the most prevalent isolated fungi. The fungal contamination rates were higher in the small factories than bigger factories and also in few factories, which usually used natural based fiber compared to those used synthetic fiber [P=0.0001]. The finishing areas had more contamination than the other parts and working areas with the topical air conditioner had lower contamination [P= 0.034]. There was a direct relationship between the amount of moisture and air fungal contamination [P=0.046], but there was no significant correlation between the whole fungal contamination rates and temperature. The results showed a high rate of contamination to fungal viable cultivable spores in Yazd textile factories. The presence of opportunistic fungi in these places, especially in summer is hazardous for immunosuppresed workers or those with malignancies or diabetes

[Survey of storage wheat contamination to zearalenone producer Fusarium species in East Azarbaidgjan]

Contamination of storage wheat to zearalenone producer molds represents a significant hazard to consumer health and has thus received increasing attention from food safety authorities and legislators. Various species of Fusarium genus are producer of different mycotoxins including zearalenone at certain conditions. These mycotoxins can enter into the human food and animal feed chain and cause premature or early thelarche, gynecomastia, primary and secondary mycotoxicosis in humans and animals. In this survey, contamination of 162 randomly collected wheat samples to zearalenone producer Fusarium was investigated using direct microscopic examination and culturing samples in specific media. From studied 162 collected wheat samples, 160 [99%] samples had fungal contamination. Aspergillus niger, Penicillium Sp, other species of Asergillus [A. Fumigatus, A. Flavous, A. Niveus, A. cchraceus,..] Fusarium Sp, Alternaria Sp, Cladesporium Sp, Gliocladium Sp. and Trichotecium Sp. were the most frequently detected microorganisms respectively. The presence of moulds sue as Aspergillus Sp, Penicillium Sp, Fusarium Sp, Alternaria Sp, Cladesporium Sp, Gliocladium Sp, and Trichotecium Sp. in consumer wheat samples can lead to the presence of harmful mycotoxins and then could result in serious toxicity and illness in humans. As the fungal contamination has a strong influence on the ultimate quality of wheat, wheat end products and food safety, more attention to the quality and safety of wheat and wheat stored places are necessary

[In vitro susceptibility testing of wheat lines used for cultivation in Yazd province against an aflatoxicogen Aspergillus flovus]

Wheat is one of the most common and important cereals with the highest cultivation rate in Iran, which highly is susceptible to contaminate with fungi particularly aflatoxinogen fungi. Using the resistant wheat lines for cultivation can be useful in controlling of wheat and food contamination to aflatoxin. The aim of the current study was to evaluate the susceptibility of the wheat, which introduced by agricultural research centre for cultivation in Yazd, against contamination with Aspergillus flavus aflatoxinogen fungi. In the current experimental study ten lines of wheat, which introduced by Yazd agricultural research centre for cultivation in Yazd province were used for an In vitro evaluation of their susceptibility to contamination with 1x10[3] conidia of Aspergillus flavus. After 48 hours the final conidia of fungus on the wheat were counted and data analyzed using Kruskal-wallis, Pearson correlation and other statistical tests. Kavir, Rhosan and Shiraz wheat samples with the mean counting of 118500, 152500, and 122000 CFU/ml [colony forming units] of Aspergillus conidia, known as the most three resistant wheat strain respectively in this study. Sistan and Akbari wheat strains with the mean561500 and 460500 CFU/ml showed the highest susceptibility rate to contamination with Aspergillus flavus conidia [P<0.001]. There wasn't seen any statistical significant correlation between the protein percent of wheat lines with their susceptibility to Aspergillus flavus [P>0.05]. However proper storage of wheat can prevent growth of microorganisms, cultivation of the resistant wheat lines can produce the resistant products and help for controlling and prevention of contamination with fungi

[Survey the role of temperature, pH and the glucose concentration on in vitro germ tube formation by Candida dubliniensis]

C. dubliniensis is a new known species in genus of Candida. Although this yeast was firstly isolated from oral lesions in AIDS patients, but recently it has been isolated from non-AIDS immunosupressed lesions as well. The ability of C. dubliniensis in production of germ tube in human serum is one of the most important virulent factors, which can induce transformation of fungi from yeast to filamentous form. This phenomenon can be altered by few environmental and nutritional factors. The general purpose of this study was to investigate the effect of temperature, pH and glucose concentrations in germ tube formation of C. dubliniensis in in vitro. The germ tube production test in human serum [with normal glucose titer] in different temperature, pH, and glucose concentrations were conducted using standard strain of C. dubliniensis [CD 34]. The average number of cells with germ tube after 2 hours and the earliest time for production of germ tube were analyzed using one-way ANOVA test. Maximum germ tube production rate were seen in 42°C, pH 7 and in concentration of 30 mg/ml glucose [P= 0.0001] and also germ tube observed in earliest time in those conditions. It seems that these environmental and nutritional factors in human body can promote this fungus to produce germ tube for invasion in susceptible patients especially in diabetics

Fungal contamination of flours in bakeries of Tabriz City

Contamination of food with mycotoxin producer fungi is common problem in production and maintenance of food and can lead to primary and secondary mycotoxicosis. Information on the fungal contamination of bakeries flours is limited and this kind of contamination is important for food and therefore this survey was undertaken to determine the fungal contamination of flour in bakeries of Tabriz city. A total of 89 samples were obtained using standard 20 cm collection tube from bakeries located in different part of Tabriz city and examined according to Iranian 997 and 2393 food standards. Samples were diluted serially [10[-2], 10[-3], 10[-4], 10[-5], 10[-6] prior cultured in YCGA medium and incubated at 25°C for maximum 21 days and a screening survey for positive samples was carried out. Of total 89 samples 61 [68.5%] were fungi free and 28 [31/5%] had fungal contamination of more than 10[4] colony forming units/gram [cfu/g]. Aspergillus and Acremonium Spp. were the most frequently detected microorganisms throughout the survey. The average of humidity of 12/8 +/- 0.76 in examined samples that was at standard frame [less than 14%].The results of this survey were similar to the results of other surveys in Iran and other countries. As the fungal contamination has a strong influence on the ultimate quality of flour end products and food safety as the major food of Iranian people, more attention to the quality of flours is necessary for minimizing of fungi contamination

[In vitro antifungal effect of aqueous garlic [allium sativum] extract and its combination with fluconazole against five common clinical candida isolated from candidiasis lesions]

Increasing rate of candidiasis prevalence and consequently use of antifungal drugs as prophylactic and curative agents has led to the widespread emergence of resistant strains. Therefore this study was designed to evaluate the in vitro antifungal activity of an aqueous extract of garlic and the synergic effect of garlic extract with fluconazole against common clinical isolates of Candida species from patients with candidiasis. The antifungal activity of aqueous garlic extract was investigated in an in vitro system using standard broth microdilution method against five common clinically isolates of Candida species including C. albicans, C. tropicalis, C. glabrata [T.glabrata], C. parapsilosis, C. krusei and 3 standard strains of Candida. The synergic antifungal effect of garlic extract in combination with fluconazole was also determined. The strongest activity of garlic extract was seen against Candida tropicalis [MIC=0.78mg/ml], C. glabrata [MIC=1.56mg/ml], and C. albicans [MIC=3.12mg/ml] respectively. C. krusei was the most resistant species against garlic extract [MIC 6.25mg/ml]. The minimum inhibition concentration of fluconazole was reduced eight folds against C. tropicalis, 4 folds against C. albicans and C. glabrata, and 2 folds for other Candida species in the presence of 3.12 mg/ml garlic extract. In comparing means, the isolated colonies [CFU] in wells without garlic extract and CFU in other wells showed statistical significant differences for C. tropicals [P=0.0001], C. glabrata [P=0.001] and C. albicans [P=0.002]. Candida species particularly resistant species such as Candida tropicalis and Candida glabrata are sensitive to aqueous extract of garlic, and combination of garlic extract with fluconazole in topical use could increase the efficacy rate of fluconazole