Effect of Saccharomyces cerevisiae yeast on ruminal detoxification of aflatoxin B[1]

Background: Yeasts are microorganisms that have the ability to absorb aflatoxins

Objectives: The effect of the yeast Saccharomyces cerevisiae [PTCC 5177] on aflatoxin B] detoxification and absorption of toxin in in vitro [the cow rumen] was investigated

Methods: For this purpose, the yeast used in various treatments [live-treated, autoclave, heat-treated, treated with acid 100 °C] was prepared and added to the rumen of cattle. Af-latoxin E in different doses [0, 5, 10,20] ppb in the rumen were added and were incubated at 37°C for one and two hours. The amount of toxin residues was measured by ELISA using Europroxima kits. RESULTS: The results showed that microorganisms that have been treated in an autoclave have the highest amount of toxin removal [90.5%] [p<0.05]. Also, with increases in the incubation time, the amount of toxin absorbed significantly increased [78%] [p<0.05] and with increasing concentrations of toxin in vitro the yeast's ability to absorb toxin increases. These results demonstrate that the major toxin is absorbed by the yeast cell wall and therefore non-living microorganisms shown an ability to absorb higher. This is because the composition of the yeast cell wall mannoprotein that are effective at absorb in toxin

Conclusions: As a strategy for the animal feed industry the use of glycomannan yeast cell wall can be useful for reducing aflatoxin B

[Comparison of salivary cotinine concentration in cigarette smokers, water pipe smokers and non smokers]

Water pipe smoking has become a public health hazard. The aim of this study was to measure and compare the concentration of salivary cotinine in cigarette smokers, water pipe smokers and nonsmokers. Forty-eight volunteers [16 cigarette smokers, 16 water pipe smokers and 16 nonsmokers] participated in this cross-sectional study. High sensitivity Salivary Cotinine Quantitative enzyme immunoassay kit was used to measure the salivary cotinine concentration. Non-parametric Kruskal Wallis test, Pearson's correlation coefficient and linear regression were used to determine the correlation between number of cigarettes smoked and concentration of cotinine. The mean concentration of salivary cotinine was 223.74[ +/- 181.56] ng/ml [the highest] in cigarette smokers, 106.24 [ +/- 135.23] ng/ml in water pipe smokers and 0.73[ +/- 1.24] ng/ml in nonsmokers. The difference in this respect among the 3 groups was statistically significant [P<0.0001]. In smokers, the level of salivary cotinine increased by 1.84 ng/ml per each time of cigarette smoking per week. This increase was 14.57 ng/ml per each time of water pipe consumption per week. The mean concentration of salivary cotinine was significantly higher among cigarette smokers compared to water pipe smokers and nonsmokers. However, one time consumption of water pipe caused a greater rise in salivary cotinine level compared to cigarette smoking

[Effect of thickness of zirconia core on marginal adaptation of all-ceramic restorations]

Marginal adaptation is important for long-term success of full-coverage restorations. Thickness of core is one of the important factors influencing the marginal integrity. Thus, the aim of this study was to evaluate the effect of different thicknesses of zirconia core on marginal adaptation of all-ceramic restorations. In this single blind in vitro study, a standard brass die 7 mm in length and 5 mm in diameter was prepared with a classic chamfer finish line with 0.8 mm depth and 10 degrees of wall taper. Copings were made using the CAD / CAM system. We had three groups of 10 samples each. Group 1 with a zirconia thickness of 3.0 mm, group 2 with a thickness of 0.5 mm and group 3 with a thickness of 0.7 mm. Copings were then placed on the die and randomly numbered. The vertical gap in the margin was measured at 10 points using scanning electron microscopy [SEM]. Data were collected. The mean and standard deviation values were calculated and ANOVA was used for the comparison of the three groups. Tukey's test was also applied. The gap in 0.3, 0.5 and 0.7 mm thicknesses of zirconia before porcelain firing was 89.21 +/- 28.90, 79.55 +/- 39.32 and 40.813 +/- 10.3 micro, respectively. The difference in marginal gap between the three groups was statistically significant [P=0.001]. Tukey's test failed to find a significant difference in marginal gap between 0.3 and 0.5 mm thicknesses [P=0.006]. But, the difference between 0.3 and 0.7 mm [P=0.001] and also 0.5 and 0.7 mm [P=0.001] was statistically significant. Based on the results, by increasing the thickness of the zirconia core marginal gap decreases in all ceramic restorations

Comparison of stress distribution in two type of metal and non metal posts by photo elastic method

Intrapulpal posts are used as retention for reconstructing of missed crown. Today fiber posts eliminated most of disadvantages of metal posts. The purpose of this study is a comparison of stress distribution in these types of posts [casting and Quartz fiber post] on root canals of teeth with photo elastic method. In this experimental study Quartz fiber and casting posts with length of 15mm and diameter of 0.9mm were used. Four epoxy resin models [10x20x40mm] were made that two of them include casting posts and two other include Quartz fiber posts. Then, cores were prepared for each model. Vertical force of 100N and oblique force with 30' and 150 N were applied on cores and isochromatic fringe patterns around post were recorded in the field of Polariscope. In the vertical loads the minimum cervical stress was observed in casting post that was 1.22 [in Quartz fiber post it was 2.65] But in apical region maximum stress was recorded in casting post that was 1.63 [in Quartz fiber post it was 1.38]. In the oblique load, casting post showd 1.39 stress in cervical that was the minimum [in Quartz fiber post it was 2.35] and in the apical region, casting post showed the maximum stress that was 1.68 [in Quarts fiber post it was 1] display more critical stress pattern [1.63]. In the vertical and oblique loads casting posts shows the maximum stress in the apical region that makes the worse fracture in tooth that couldn't be prepared but in Quartz fiber post maximum stress was in cervical region so it is more repairable

[Comparison of the effects of three preparation designs: shoulder, chamfer and deep chamfer in the palatal surface on resistance against breakage of porcelain laminate veneer]

Statement of Problem: Porcelain laminate veneer is one of the most important restorations in dentistry because of stable esthetic and low destructive technique. But the main reason of failure in this treatment is porcelain fracture. Therefore, tooth preparation has an important role in fracture resistance of porcelain laminate veneer

Purpose: The aim of this in-vitro study was to compare the effect of tree preparation designs, shoulder and chamfer and heavy chamfer, on fracture strength of porcelain laminate veneer

Materials and Method: This experimental and in-vitro study was performed on 30 upper central teeth without fracture, carries or any problem. The teeth were divided into three-10 teeth groups. Then, the preparation design was performed perfectly. In the palatal surfaces of the first group we used deep chamfer preparation design and the shoulder and the chamfer designs were performed for the second and third groups, respectively. Then the samples were put in instron machine with the angle of 30 degrees. The force rate which led to break in those samples was determined. The data were analysed using t-test

Result: Resistance against breakage in the deep chamfer, shoulder and chamfer groups were 283.40 17, 231.50 25.61 and 254 21.71 Newton, repectively. No significant difference was found among the groups

Conclusion: The higher fracture resistance was observed in deep Chamfer/palatal over lap technique, so we prefer to use this kind of preparation for palatal extension of Porcelain Laminate Veneers

[Marginal fitness comparison between three systems: IPS empress 2, IPS e.max press, and In-Ceram]

Marginal gap determines the success rate in all ceramic crown restorations. However, there is insufficient information about marginal fitness of different ceramic systems. The aim of this study was to compare the marginal gap in three different kinds of ceramic restorations namely "In-Ceram", "IPS-e.max Press" and "IPS Empress2". This in-vitro experimental investigation was conducted using a single blind technique. A total of 10 upper incisor teeth were prepared with size reduction 7mm in height, and 5mm diagonally. With a 1mm shoulder finishing line and tapered about 3 degrees. Then 10 ceramic crowns were built on top of each preparation. After cementation they were grinded at buccolingual direction. Finally, marginal gap analysis was conducted using Stereotactic electronic microscope [SEM]. The marginal gap in IPS e.max pres was 29.22 [ +/- 8/59] microm. In-Ceram showed 49.94 [ +/- 9/32] microm and IPS Empress 2 group demonstrated 40.88 [ +/- 5/84] microm. The gap in IPS e.max Press was less than the gap in In-Ceram and IPS Empress 2 in full ceramic restorations

relation of water contamination and colibacillosis occurrence in poultry farms in Qom province of Iran

Seventy poultry farms' drinking water was tested for Escherichia coli contamination in Qom province in Iran. The cases of colibacillosis from positive farms were also collected and tested. The isolates were examined for serotype, detection of virulence genes by multiplex PCR and antibiotic resistance. Thirty poultry farm water samples were E. coli positive [18.57%], although 13 E. coli isolates were recovered from carcasses of related farms. The isolates belonged to O2 serogroup and one O157, with approximately 29% of the strains being non-typeable. Two isolates from water and carcasses were serotyped O2 and one sample serotyped O157, which needs to be further studied. The PCR method was on the basis on showing virulence genes of espB, stxl, stx2 genes were common in a sample from both water and carcass, although five samples from both water and carcass shared a stxl gene as well. All isolates showed maximum sensitivity and resistance to lincospectine and tetracycline, respectively

[Comparison of fracture strength between two systems: IPS empress 2 and IPS E. max press]

Statement of problem: One of the major problems of all-ceramic restorations is their probable fracture against lateral forces. However there is not enough information about fracture strength of various all-ceramic restorations

Propose: The aim of this experimental research was to compare the fracture strength and the most probable fracture points in all-ceramic restorations

Materials and methods: In this laboratory-based experimental study, 10 symmetric crowns from each IPS Empress2 and IPS e. max press system were constructed on a laboratory model for maxillary central incisor with 2mm occlusal reduction and deep chamfer finishing line. The core thickness was between 0.7-0.8 mm and porcelain was placed over the core using the layering technique. Each of the crowns was cemented onto the dye using Dual cure Variolink II cement and were imposed to compressive forces in Universal testing machine [V=1mm/min] at 30 degrees angle in palatal surface until the fracture occurred. Then the samples were inspected for fracture points by observation. The statistical evaluations were done with Independent Sample T-test [alpha=0.05]

Result: The average force leading to fracture was 385 N [SD=79/96] for IPS Empress 2 and 380 N [SD=106/28] for IPS e. max press. The most common fracture points in two groups were the incisal edge and buccal surface. There was no meaningful statistical difference in fracture force between the two systems [P>0.05]

Conclusion: The findings of this research indicated that there is no meaningful statistical difference between these two systems in their fracture strength. therefor they are both suitable for constructing anterior all-ceramic restorations

Comparison between two chlorine disinfectants as a post milking teat dip in dairy cows

In order to determine the efficacy of Agrisept tablets as a postmilking teat dip 30 Holstein cows, at 2 months after parturition were included. Subclinical mastitis was determined by analyzing the degrees of shirazma in milk samples at the beginning and the end of the first, second, third and fourth weeks of the study. Bacterial culture samples were obtained from milk of all the infected quarters. Agrisept was used as a teat dip for right and Benzalconium chloride for left quarters throughout the study [one month] and teat skin and its orifice were monitored for teat injuries. The numbers of infected quarters from the two groups at the mentioned times of the study were statistically analyzed with fisher exact and chi-square tests. Results showed that degrees of Shirazma test in the left and right quarters were significantly lower in Agrisept group at the end of first [p < 0. 038], second [p < 0. 42], third [p < 0. 56], and fourth weeks of study[p < 0. 03]. Bacterial culture of milk samples revealed; new intramammary infection of total bacteria [p > 0. 05] and Staphylococcus aureous [p < 0. 05] were greater in Agrisept compared to Benzalconium chloride group. It has been concluded that more studies are needed especially to evaluate the preventive effect of Agrisept on new infection rate of Staphylococcus aureous, before prescribing Agrisept as an effective teat dip