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Alkaline peroxide mechanical pulping of paulownia wood harvested from exotic tree plantations in northern Iran was investigated. The fiber length, width, and cell wall thickness of this wood were measured as 0.82 mm, 40.3 µm, and 7.1 µm, respectively. The chemical composition including cellulose, lignin, and extractives soluble in ethanol-acetone, 1% NaOH, hot and cold water was determined as 49.5%, 25%, 12.1%, 26.9%, 11.4%, and 8.1% respectively. The ash content of this wood was 0.45%. Pre-washed chips were chemically treated at 70°C for 120 minutes with different combinations of three dosages (1.5, 3, and 4.5%) of hydrogen peroxide and three dosages (1.5, 3, and 4.5%) of sodium hydroxide prior to defibration. Other chemicals including DTPA, sodium silicate, and MgSO4 were constant at 0.5%, 3%, and 0.5%, respectively. The results showed that using a 1.5% hydrogen peroxide and 4.5% sodium hydroxide charge, the brightness of APMP pulp reached 68.7% ISO and higher chemical dosages did not improve the brightness; however, to produce APMP pulp with higher strength, a sodium hydroxide charge of 4.5% was needed. The tensile strength, tear strength, burst strength indices, and bulk density of the APMP pulp produced from 1.5% hydrogen peroxide and 4.5% sodium hydroxide were measured as 15.5Nm/g, 6.54mN.m²/g, 0.56kPa.m²/g, and 3.47cm³/g, respectively. The resulting pulp was bulky and is suitable for use in the middle layer of boxboard to provide the desired stiffness with a lower basis weight. [ABSTRACT FROM AUTHOR]

Introduction: Microorganisms that store lipids due to nutrient deficiencies (especially nitrogen) produce microbial oils following inhibition of growth. Based on the structure of fatty acids, microbial oils have industrial applications. The main purpose of this study, the first in Iran, was to evaluate the production of single-cell oil from Rhodococcus erythropolis PTCC 1767 using lowcost materials. Material and Methods: In the present study, Rhodococcus erythropolis PTCC 1767 as bacterial strain, whey, wheat straw, glucose, and glycerol were used for carbon sources and yeast extract was used for the nitrogen source. The bacterial strain was cultured in the MSM medium. FTIR analysis was performed to confirm the presence of carbon groups, GC analysis for identifying fatty acids, and Sudan black staining and imaging with a Transmission Electron Microscope (TEM) for observing the lipid granules stored inside the cell. Results: The highest lipid production in the presence of carbon sources was related to whey in 96 hours with 23.22% and the maximum lipid production was obtained using wheat straw in 72 hours with 20%. Discussion and Conclusion: The results of the present study demonstrated that Rhodococcus strains have the ability of bioconversion of low-cost carbon sources wheat straw and the whey to microbial oils and this can serve as a platform for eco-friendly biotechnological processes. [ABSTRACT FROM AUTHOR]

Statement of Problem: One of the most clinical challenging issues in prosthodontics is debonding of soft liners from the denture base. Purpose: The aim of this study was to evaluate and compare tensile bond strength between soft liner and heat-cured acrylic resin when immersed in two different types of denture cleanser and distilled water, at different period of times. Materials and Method: In this experimental in vivo study, 238 heat-cured acrylic blocks were made. A soft liner was embedded between the acrylic blocks. Samples were divided into four groups: 17 samples were in the control group and were not soaked in any solution .The remaining samples were divided into 3 groups (Distilled water, Calgon and Fittydent). Each group was then subdivided into two subcategories, regarding the immersion time variable; 15 and 45 minutes. All samples were placed in tension force and tensile bond strength was recorded with the testing machine. One- way ANOVA and Tucky HSD post-hoc test were adopted to analyze the yielded data (α> 0.05). Results: Specimens which were immersed in two denture cleansers (Fittydent and Calgon) and in distilled water showed significant difference (p= 0.001) in bonding strength when compared to the control group. The subjects immersed in denture cleanser solutions and distilled water did not reveal any significant difference (p= 0.90). For all groups; most of the bonding failures (72%) were cohesive type. Conclusion: The effect of the denture cleansers and distilled water on the bond strength was not statistically different; however, the difference was significant between the immersed groups with the non-immersed group. Moreover, type of the denture cleanser did not show any effect on the tensile strength. The tensile strength increases with time of immersion. [ABSTRACT FROM AUTHOR]