Background: Cryogenic methods have been used to increase the wear, abrasion, corrosion resistance and to improve the strength of metals. The aim of this study was to evaluate the effect of cryogenic treatment on the cyclic fatigue resistance of rotary nickel-titanium (NiTi) instruments. Materials and Methods: In this in vitro study, 20 Hyflex (Coltene, Altstätten, Switzerland) nickel-titanium instruments, size 25, 0.06 taper, were randomly divided into two groups as follows: untreated NiTi rotary files (Group A) and cryotreated NiTi rotary files (Group B). The instruments of Group A were completely immersed in a cryocan containing liquid nitrogen (–196°C) for 24 h. After 24 h, the instruments were removed from the bath and were allowed to return to room temperature gradually. All files were used (at a speed of 500 rpm and a torque of 2.5 Ncm) in an artificial canal with a 60° curvature until fracture. Time to failure was recorded with a stopwatch in seconds and subsequently converted to number of cycles to fracture (NCF). Groups were compared using the independent-samples t -test. The level of statistical significance was set at 0.05. Results: Mean NFCs in Group A and B were 1576 and 1395, respectively. However, statistical analysis showed that there was no significant difference between the groups ( P = 0.2). Conclusion: Deep cryotherapy of NiTi endodontic files cannot improve the cyclic fatigue resistance of HyFlex files, but further studies are required to evaluate these cryogenically treated NiTi files clinically.
Enterococcus faecalis is a resistant microorganism and plays an important role in root canal treatment failure. One of the most critical steps in root canal treatment is chemical cleaning of the root canal with endodontic irrigation solutions. The most commonly used solution is Sodium hypochlorite which in spite of its broad antimicrobial activity, has many disadvantages. Therefore, this study was designed to evaluate the antibacterial effect of eucalyptus and ginger on dentinal tubules Enterococcus faecalis in the presence of smear layer. In this study dentin cylinders from 80 single rooted human teeth were prepared and contaminated with Enterococcus faecalis with smear layer created in each dentin disk. Experimental groups were as follows: Group 1: Sodium hypochlorite 5.25%, Group 2: ginger extract, Group 3: eucalyptus extract, Group 4: Normal saline (positive control), Group 5: sterile cylinders. Then dentin chips were collected from three different depths of dentin including 0.1,0.2 and 0.3 millimeters. Optical density comparison of different experimental groups showed that there is a signifi cant difference between groups in 0.1 and 0.2 millimeters depth (p<0.01), however no signifi cant difference in 0.3 millimeters depth was obtained. Antimicrobial effi cacy of eucalyptus and Sodium hypochlorite in the presence of smear layer showed no signifi cant differences, while this effect was weaker with ginger compared to Sodium hypochlorite.
In 2014, over 180 thousand hectares and 1.223 million tons of Maize produced in Iran. However Iran is a major importer of Maize in the world. Kermanshah is located in Western Iran and Maize is the most important crop after wheat. Maize production in this province has two major problems: water shortage caused and low percentage of organic matter in soil. In this research, effects of vermicompost and Azotobacter as a boi-fertilizers and chemical fertilizers on yield and yield components of Maize under normal and defi cit irrigation was investigated in two sites in 2014 and 2015. Site included normal irrigation and defi cient irrigation (65% optimum water requirement) and each site was conducted as the factorial split plot in a randomized complete block design with three replications. Treatments included Azotobacter in the main plots (non-inoculation and inoculation), vermicompost (consuming 0, 2, 4 and 6 ton/ha) and chemical fertilizers included N,P,K in tree levels (100% recommendation based on soil test, 50% recommendation and no fertilizer) in the sub plots. Results showed that grain yield, 1000 kernels weight, number of kernels per row, number of kernels per ear and plant height were decreased by defi cient irrigation. Use of Azotobacter and vermicompost signifi cantly increased these traits in normal and defi cit irrigation, Results also showed that using 6 ton/ha of vermicompost and Azotobacter in soil, 50% of the corn fertilizer supplied. The results showed that combined use of bio-fertilizers with chemical fertilizers increased the yield and yield component. Therefore the uses of biological fertilizers signifi cantly reduce the consumption of chemical fertilizers and reduce the adverse environmental effects. So biofertilizers could be considered as a suitable substitute for chemical nitrogen fertilizer in organic agricultural systems. On the other hand from this experiment, application of vermicompost in combination with chemical fertilizers showed better performance than only chemical fertilizers, even in 100% recommendation based on soil test treatments.
Infections due to Vancomycin Resistant Enterococcus (VRE) are increasing worldwide. Resistance of VRE to glycopeptides antibiotics is related to van A,B,C,D,E genes which decreases the impact of this antibiotics on the cell wall of bacteria , making these bacteria innately Tuberamycin-resistant. Therefore, Jentamicin is used to treat infections. In recent years it has been reported that many of VRE are showing high resistance to Aminoglycosids and even to Jentamycin. There have been reports on distribution of VRE strains in clinical environments. This research was done to obtain novel antimicrobial agents which is effective against VRE infections. Enterococcus mainly cause nosocomial infections especially in ICU and CCU sections of hospitals and are threat to patients. Soil samples were collected from agricultural soils of Qom. Then isolation and primary identifi cation of Streptomycetes was done on ISP4 culture medium. Then the antimicrobial activity of all Streptomycetes obtained were examined against VRE on Hickey-Trenser medium, Brain-heart infusion medium, Muller-Hinton agar with cross-streak method. Five out of 125 isolates showed inhibitory effect on VRE. In the next step the Streptomycete Strain that left bigger inhibition zone against VRE on medium were selected to be characterized biochemically and morphologically and was named as E.P1. Additionally were identifi ed on the basis of its 16S rRNA sequence. Identifi cation results indicated that the obtained Streptomyces strain is 100% similar to Streptomyces tendae ATCC 19812.Finally, GC-Mass analysis was done on the antimicrobial agent that was extracted by ethyl acetate. Results revealed that it was a quinuline compound.
Background and Aim: The hepatit is one of the most common and serious elements of hepatitis in the world. The cause of the infection is unknown but previous findings indicate that disturbance in function of immune system, B lymphocyte, Foxp3, CD4 + and CD8 + are the probability causes. The candida species are the natural mouth florae in very people and exist in the mouth of the carrier people in lower concentration about 200-500 cells in one milliliter of saliva. The goal of this search was to comparison the level of oral Candida albicans in healthy and HBsAg + persons referred to Ahwaz Transmittal Blood Organization in 2008.
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