Background & Aim: Considering the pathogenesis of nursing caries, the emphasis has more been focused on microorganisms, especially streptocucus mutans, There are also multiple factors interfering the onset of this disease, the immunological responses of the host are one of the them. Among different immune factors, there has been little attention to the role of neutrophils, though they act as the frontiers in defense mechanism. So this study was done with the aim of evaluating the relation of salivary neutrophil percent in children with baby bottle tooth decay and caries free children in 3-5 years old kids in Tehran kindergartens.Methods & Subjects: Thirty - six children with nursing caries and 36 caries free kids were selected for this analytical cross sectional study. All the basic variables which might had affected on neutrophil rate were omitted. One ml of saliva was obtained from all children and a fruity was prepared for each case to compare the results. To prevent the bias all the samples were coded. The analysis was performed by SPSS ver10.0 software and chi - square analysis. Results: The neutrophils count in samples with early childhood caries was 23.6±11.4 and 17.6±11.2 in caries free kids. Saliva neutrophil count in kids with nursing caries was significantly higher than caries free children (P<0.02). Conclusion: In nursing caries the polymorphonuclears (Neutrophils) migrate into the oral cavity and a significant increase in their rate is observed in saliva, indicating their effort for defence.

There are more scatter in experimental creep crack growth data observed in the early stages of a test than later on. This scatter can be attributed to a combination of factors; such as stress redistribution from the initial elastic state to the steady state creep, primary creep effects and the buildup of damage local to the crack tip during the early crack growth period. In this paper the redistribution of stress and the buildup of damage at a crack tip during creep in a cracked body is considered. For short times after application of load, crack growth rate can be described by stress intensity factor K for long times, if the stress fields relax to their steady sate, then C* can describe the magnitude of the stress fields and so the crack growth rate.A new method has been developed for the time needed for the stresses to relax from their elastic state to some fraction between the elastic and creep state. Also a new creep crack growth model is proposed in terms of ductility exhaustion to account for buildup of damage at a crack tip. It is shown that this build-up of damage is the most likely cause of increased scatter.

To investigate the response of corn to combined application of chemical fertilizers with rhizobacteria plant growth promoting, an experiment was conducted in 2017 at Research farm of Agricultural and Natural Resources Campus of Tehran University, Karaj, Iran, in a randomized complete block design with four replications. Four nutritional treatments including T1 (Control treatment without applying fertilizer), T2 (Just PGPRs), T3 (Use chemical fertilizers based on soil test) and T4 (T3 + PGPRs) were considered. According to the results, the highest total dry weight (3.9 kg/m2), crop growth rate (79.8 g.m-2.day-1), net assimilation rate (15.3 g.m-2.day-1) and grain yield (18.2 ton.ha-1) were observed in T4 treatment and T2 treatment produced the highest  leaf area index (5.3), leaf area duration (205.2) and specific leaf weight (78.5 g.m-2) . Also, the lowest value of all traits was observed in in T1 (control) treatment. The results showed that the presence of rhizobacteria plant growth promotioninduction in the corn nutrition program increased the growth and growth indices of the plant. Combined application of chemical fertilizers with rhizobacteria plant growth promoting resulted in the highest growth and final grain yield of corn.

This study was carried out to investigate the effects of different water application rate (40, 60, 80, 100 and 120 percent of water requirement) on the yield and water use efficiency (WUE) of the early Urbana tomato. This experiment was performed at the research farm of the College of Agriculture of the Tehran University (a semi-arid area) on a clay–loam soil, using a randomized complete block design with three repetitions. The results indicated that the different treatment had a significant effect (1% level) on yield and WUE of tomato. The maximum yield and WUE obtained at 100% water requirement. Furthermore, it was observed that the reduction of water application rate by 20, 40 and 60 percent reduced the crop yield 24.04, 57.13 and 74.10 percent, respectively.

Moringa peregrina is the only species of the Moringa genus, which is growing naturally, in Southeast part of Iran. The species has industrial and medicinal values as well as environmental importance, which is suffering genetic erosion in the nature. Seeds were sampled on single plants of six plant populations in the habitats of the species in the country. The seeds were sown and several early growth stage characteristics were recorded on the seedlings based on a statistical design. Since the single trees of each plant population were not the same also the progenies of each single mother plants were not the same, the collected data were analyzed based on a nested model. Results of the analysis revealed that the plant populations were not significantly different based on the studied seedling characteristics and the majority of the differences belonged to within populations rather than between populations. Using expected mean squares, the results of analysis of variance were divided to their components. The analysis also showed that trees within population component of variance were stronger than the other components and the population component was not remarkable. Although the growth characteristics of the tree species would be more visible on higher ages of the trees, but the negligible genetic variation of the characteristics on the valuable species may be due to genetic erosion.