Penetration Depth of Sodium Hypochlorite in Dentinal Tubules after Conventional Irrigation, Passive Ultrasonic Agitation and Nd:YAG Laser Activated Irrigation

Introduction: The penetration depth of irrigating solutions in dentinal tubules is limited; consequently, bacteria can remain inside dentinal tubules after the cleaning and shaping of the root canal system. Therefore, new irrigation systems are required to increase the penetration depth of irrigating solutions in dentinal tubules.Methods: A comparative study regarding the penetration depth of sodium hypochlorite (NaOCl) solution in dentinal tubules using four methods, (1) conventional irrigation (CI), (2) smear layer removal plus conventional irrigation (gold standard), (3) passive ultrasonic agitation (PUA) and (4) Nd:YAG laser activated irrigation (LAI), took place on 144 extracted mandibular teeth with a single root canal. After decoronation with a diamond disc and working length determination, the apical foramen was sealed with wax. The canals were prepared up to #35 Mtwo rotary file and 5.25% NaOCl was used for irrigation during preparation. To study the penetration depth of NaOCl, smear layer was eliminated in all samples. Dentinal tubules were stained with crystal violet and after longitudinal sectioning of teeth, the two halves were reassembled and root canal preparation was performed up to #40 Mtwo rotary file. Then the samples were distributed into four experimental groups. Depth of the bleached zone was evaluated by stereomicroscope (20X). Data were analyzed by Kruskal-Wallis test.Results: The highest and lowest average for NaOCl penetration depth in all three coronal, middle and apical sections belonged to CI + smear layer removal and CI. A statistically significant difference was seen when comparing the penetration depth of CI + smear layer removal group to CI and PUA groups in coronal and middle third, in which the average NaOCl penetration depth of the gold standard group was higher (P < 0.05). A statistically significant difference was seen between CI + smear layer removal group and the other three groups including CI, PUA and LAI in apical third, in which the average NaOCl penetration depth in the gold standard group was higher (P < 0.001).Conclusion: The standard protocol for smear layer removal led to more effective smear layer elimination and deeper penetration depth of irrigation solutions. PUA and LAI groups exhibited less smear layer elimination and penetration depth of irrigation solutions. Therefore, CI+smear layer removal should still be considered as the gold standard

Biomass Expansion Factors (BEFs) and Carbon Stock for Brant's Oak (Quercus brantii Lindl.) Forests in West-Iran

Investigating a tree’s biomass can provide basic information about forest carbon stock. The Biomass Expansion Factor (BEF) is a variable for estimating carbon stock of forests. The aim of this study was to analyse the Above Ground Biomass (AGB) allocation, developing the BEF and carbon stock for two vegetation forms of Brant’s Oak (Quercus brantii Lindl.) based on forest inventory data. BEF is defined as the ratio of AGB to crown volume variables. The study data were taken from 30 trees that include 16 individual trees with single stem and 14 coppice shoots located in West-Iran. The trees selected were felled and separated into different components including: bole, main branches, lateral branches, twigs and leaves. The fresh weight of the trees was obtained with a portable hanging scale and several samples were taken from each tree component. The results of this study showed significant differences between component biomass proportions of the two vegetation forms of Brant’s Oak trees and determined average biomass and carbon content of the forms studied. We also conclude that BEF of Brant’s Oak could be improved by applying crown variables. According to the results, BEFs are tree-size dependent variables. Finally, this study indicates that age-dependent BEFs cannot be applied to conditions where stand development deviates from the conditions that in which the BEFs were developed

Responses of soil microbial biomass and enzyme activities to tillage and fertilization systems in soybean (Glycine max L.) production

Tillage operation and fertilizer type play important roles in soil properties as far as soil microbial condition is concerned. Information regarding the simultaneous evaluation of the effect of long-term tillage and fertilization on the soil microbial traits of soybean farms is not available. Accordingly, it was hypothesized that, the microbial biomass and enzyme activity, more often than not, respond quickly to changes in soil tillage and fertilization. Therefore, the experiments were aimed at analyzing the responses of soil microbial traits to tillage and fertilization in a soybean field in Kurdistan University, Iran. The field soil is categorized into coarse Loamy, mixed, superactive, calcareous, and mesic Typic Xerorthents. The experiments were arranged in split plot, based on randomized complete block design with three replications. Main plots consisted of long-term (since 2002) tillage systems including conventional tillage (CT), minimum tillage (MT) and no-tillage (NT). Eight fertilization methods were employed in the sub-plots, including (F1): farmyard manure (FYM); (F2): compost; (F3): chemical fertilizers; (F4): FYM + compost; (F5): FYM + chemical fertilizers; (F6): compost + chemical fertilizers; (F7): FYM + compost + chemical fertilizers and (F8): Control (without fertilizer). The highest microbial biomass carbon (385.1 μg) was observed in NT-F4 treatment. The NT treatment comparatively recorded higher values of acid phosphatase (189.1 μg PNP g-1 h-1), alkaline phosphatase (2879.6 μg PNP g-1 h-1) and dehydrogenase activity (68.1 μg PNP g-1 h-1). The soil treated with a mixture of compost and FYM inputs had the maximum urease activity of all tillage treatments. Organically manured treatment (F4) showed more activity in dehydrogenase (85.7 μg PNP g-1 h-1), acid phosphatase (199.1 µg PNP g-1 h-1) and alkaline phosphatase (3183.6 µg PNP g-1 h-1) compared to those treated with chemical fertilizers. In NT-F4 treatment, using on-farm inputs is most suitable for sustainable management and improvement in soil biological activities in soybean cultivation. We concluded that applying organic manures and employing reduced tillage systems increased soil microbial biomass and enzyme activities

Site demands and some silvicultural characteristic of Caucasian false walnut (Pterocarya fraxinifolia Spach.) in Lorestan province

بررسی خصوصیات رویشگاهی و جنگل‌شناسی توده لرگ در استان لرستان      This research was carried out to identify the site demands and silvicultural characteristics of Caucasian false walnut in Lorestan province, south western of Iran, far from its common natural habitat in northern Iran. Considering the small distribution area of this species, 100% inventory of qualitative and quantitative characteristics of all trees were made. Moreover, the climatic condition and soil properties of the stand were studied. Results showed that climate of the studied area is semi-humid and cold. The stand appears at a stream terrace in the calcareous bedrock, clay loam soil with a pH of 7.5. Almost 58% of trees were coppice while only 42% had seed origin. The minimum and maximum diameter of false walnut trees were 2 and 28 cm, respectively. The mean annual diameter increment was calculated to 3.8 mm and the total volume was estimated to 389.5 m3ha-1. The minimum, maximum and mean height of trees were 2.3, 28 and 19.1 m, respectively. The frequency of regeneration was estimated to 15226 per hectare

Effect of nitrogen (N) fertilizer and foliar-applied iron (Fe) fertilizer at various reproductive stages on yield, yield component and chemical composition of soybean (Glycine max L. Merr.) seed

Nutritional management is an important factor in the success of crop production. However, research on the effects of nitrogen (N) and iron (Fe) application on soybean yield is limited. In order to study the effects of N and Fe application at various reproductive stages on grain yield and quality of soybean seed, an experiment was conducted using a factorial arrangement based on randomized complete block design with three replications at the research farm of Kurdistan University in 2009. The experimental treatments consisted of three different levels of N fertilizer application as follows: 0, 50 and 100 kg N ha-1, and two levels of Fe fertilizer (spray with iron and non-sprayed). Results indicate that the maximum seeds yield was obtained at N1 (303 g m-2) and N2 (328 g m-2) treatments and the highest number of seed per plant was obtained at N2 (128) treatment. Potassium concentration in seed and SPAD chlorophyll value responded to fertilizer treatments and the maximum protein percentage (32.5%) was obtained at N1F1 treatment. This treatment had no significant difference with N1F0, N2F0 and N0F1 treatments. The Fe and N fertilization treatments had no significant effect on Fe, Zn, Ca, Na, Cu and P concentration of soybean seed.Key words: Fe and N fertilizers, seed mineral elements, soybean, yield

Biomass and carbon Stocks of Brant's oak (Quercus brantii Lindl.) in two vegetation forms in Lordegan, Chaharmahal & Bakhtiari Forests

Estimates of tree biomass are useful in assessing forest structure and evaluating ecological and economic processes such as nutrient cycle, forest productivity and fuel inventories. The information on tree biomass is required to assess the amount of carbon held in trees. This research was conducted in order to measure biomass and Carbon stocks of two vegetation forms of Brant's oak (Quercus brantii)  in Chaharmahal & Bakhtiari Forests in west of Iran. Therefore, sample trees were selected to be felled using 30 randomized systematic plots. Thirty trees including 16 individuals with single stem and 14 sprout-clumps were randomly selected. Quantitative and qualitative traits were measured before felling. The felled trees were separated into six different components and weighed on a portable hanging scale in the field in order to obtain the fresh weight. Samples were taken from each tree component. The samples were weighed on a scale with 0.01 gr accuracy and transported to a laboratory. According to results, biomass of single stem trees was 2.5 times more than coppice forms. Moreover, biomass allocation of single stem trees and coppice trees were identified