High Velocity Impact Response of Basalt Fibers/Epoxy Composites Containing Graphene Nanoplatelets

The effects of adding surface modified graphene nanoplatelets (GNPs) in various weight percentages (0, 0.1, 0.2, 0.3, 0.4, 0.5 with respect to matrix) on the high velocity impact response of basalt fibers/epoxy composites were evaluated. High speed mechanical stirrer and ultrasonic waves were used for the dispersion of GNPs in the epoxy matrix, and hand layup method was utilized for the fabrication of the composite samples. High velocity impact testing was performed using a conical projectile. The results demonstrated that the maximum improvement in the impact limit velocity and energy absorption occurred in the 0.3 wt.% GNPs nanocomposite, i.e., 11 and 23 %, respectively. Also, the electron microscopy studies revealed that the addition of GNPs contributed in improving the impact properties by influencing the matrix and thus enhancing the interfacial characteristics between the basalt fibers and the matrix.     

Effect of Cattle Manure and Sulfur on Yield and Oil Composition of Pumpkin (Cucurbita pepo var. Styriaca) Inoculated with Thiobacillus thiooxidans in Calcareous Soil

The effect of cattle manure and sulfur fertilizer on seed yield and oil composition of pumpkin (Cucurbita pepo var. Styriaca) under inoculated with Thiobacillus thiooxidans was investigated in a factorial study based on a randomized complete block design. Experimental factors consisted of cattle manure (M) (M₀: 0, M₁: 10; and M₂: 20 t ha^?1), sulfur (S) (S₀: 0, S₁: 250; and S₂: 500 kg ha^?1) and T. thiooxidans (B): inoculated (B₁) and non-inoculated (B₀). Results demonstrated that the application of T. thiooxidans, cattle manure, and S fertilizer decreased the soil pH. The largest number of seed per fruit (367), highest fruit yield (70.57 t ha^?1), seed iron (Fe) content (16.26 mg 100 g^?1), and seed yield (111 kg ha^?1) was obtained when 20 t ha^?1 manure was applied in combination with 500 kg ha^?1 S inoculated with T. thiooxidans. In this condition, the content of S, Fe, phosphorus (P), and nitrogen (N) in plant shoots was increased by 44.8%, 22.58%, 33.89%, and 10.38%, respectively, compared to the control. Moreover, the highest content of seed protein was observed in 10 t ha^?1 manure and 500 kg ha^?1 S fertilizer inoculated with T. thiooxidans. When 250 kg ha^?1 S fertilizer was applied, 20 t ha^?1 manure decreased seed P content sharply. At the rate of 500 kg ha^?1 S fertilizer, the highest content of seed P was obtained from 20 t ha^?1 manure. Totally, 20 t ha^?1 cattle manure, along with 500 kg ha^?1 S fertilizer as well as T. thiooxidans inoculation, improved oil and seed yield of medicinal pumpkin.     

Application of Zeolites for Sustainable Agriculture: a Review on Water and Nutrient Retention

Developing urbanization, water shortage, watercourse pollution, and demands for more food due to population growth require a more efficient water irrigation and fertilizer application. Retaining nutrients and water in agricultural soils brings about higher crop yields and prevents pollution of water courses. Among different solutions, zeolites, which are environmental friendly, ubiquitous, and inexpensive, have been extensively employed in agricultural activities. These minerals are considered as soil conditioners to improve soil physical and chemical properties including infiltration rate, saturated hydraulic conductivity (K _s), water holding capacity (WHC), and cation exchange capacity (CEC). Natural and surface-modified zeolites can efficiently hold water and nutrients including ammonium (NH₄ ⁺), nitrate (NO₃ ^?) and phosphate (PO₄ ^3?), potassium (K⁺), and sulfate (SO₄ ^2?) in their unique porous structures. Their application as slow-release fertilizers (SRFs) are reported as well. Therefore, zeolite application can improve both water use efficiency (WUE) and nutrient use efficiency (NUE) in agricultural activities and consequently can reduce the potential of surface and groundwater pollution. This review paper summarizes findings in the literature about the impact of zeolite applications on water and nutrient retention in the agriculture. Furthermore, it explores benefits and drawbacks of zeolite applications in this regard.

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Effects of nanoclay on physical and mechanical properties of wood-plastic composites

Effects of nanoclay (NC) on physical and mechanical properties of wood-plastic composite (WPC) were studied here. Virgin, recycled, and mixed (50/50% of virgin/recycled) polyvinyl chloride (PVC) were used as the matrix in the WPC. Specimens with three NC contents of 1.5%, 3%, and 5% were manufactured; they were then compared with control specimens. Totally, 12 treatments were manufactured. The physical and mechanical properties were measured in accordance with the ASTM standards. The highest properties were found in specimens made from virgin PVC. Addition of recycled PVC resulted in significant decrease in all properties. NC improved all physical and mechanical properties studied in the present research project; the highest properties were observed in specimens with 5% of NC content. The improvement in properties was as a result of formation of bonds between the hydroxyl groups of NC with the wood flour components. It was concluded that NC would significantly improve the properties in all the three PVC types of virgin, recycled, and mixed. From an industrial point of view, it was concluded that mixing virgin and recycled PVC can be recommended not only to decrease production costs, but also to partially solve the problem of PVC residue which are not bio-degradable.     

Assimilate and nitrogen remobilization of six-rowed and two-rowed winter barley under drought stress at different nitrogen fertilization

Field experiments were conducted to investigate the effects of irrigation regimes and N levels on assimilate remobilization of two barley cultivars (Yousef_six-rowed and Nimrouz_two-rowed) in 2011 and 2012. There were three levels of water regimes (full irrigation (I₁₀₀), 75% and 50% of I₁₀₀: I₇₅ and I₅₀, respectively) in 2011. Rain-fed treatment (I₀) was included in 2012. Three N levels (0, 60, and 120 kg ha^?1) were used. Grain yield and assimilate remobilization decreased by severe water stress (I₀), however, the reduction of them were intensified by N fertilizer application. The N remobilization was negatively affected by N fertilization and water stress. The two-rowed showed higher N remobilization (10.7%) and contribution of N remobilized to N content of grain (5.8%) than the six-rowed. The two-rowed cultivar showed significantly higher assimilate remobilization and grain yield than the six-rowed under I₅₀ (26.3% and 6.5%, respectively) and I₀ (48.7% and 17.1%, respectively), while the six-rowed had similar or higher performances in terms of these traits under I₁₀₀ and I₇₅. This study showed that optimizing irrigation and N rates (decrease N level with increasing water stress) and selection of the suitable cultivars (Nimrouz_two-rowed) might increase assimilate remobilization and consequently grain yield under drought stress conditions.     

Egyptian broomrape (Phelipanche aegyptiaca) response to silicon nutrition in tomato (Solanum lycopersicum L.)

Egyptian broomrape is a root holoparasitic plant that causes severe damage to tomato in Iran. Experiments were conducted in 2013 to investigate the effect of silicon (Si) nutrition on broomrape response in tomato. Si concentration significantly delayed first appearance of broomrape and decreased number of tubercles in both cultivars, although the magnitude of reduction varied with cultivar and Si concentration. Broomrape infection significantly decreased root and shoot dry weights of tomato cultivars. However, Si nutrition at high concentration considerably reduced damage severity of broomrape compared to the treatment that received no Si. Infection of tomato with broomrape resulted in significant increase in peroxidase and catalase activity in the roots of resistant cultivar which led to enhanced crop resistance to oxidative stress and improved growth in this cultivar.     

Radiosensitivity and repair kinetics of gamma-irradiated leukocytes from sporadic prostate cancer patients and healthy individuals assessed by alkaline comet assay

Background: Impaired DNA repair mechanism is one of the main causes of tumor genesis. Study of intrinsic radiosensitivity of cancer patients in a non-target tissue (e.g. peripheral blood) might show the extent of DNA repair deficiency of cells in affected individuals and might be used a predictor of cancer predisposition. Methods: Initial radiation-induced DNA damage (ratio of Tail DNA/Head DNA), dose-response curves and kinetics of DNA repair in leukocytes from healthy volunteers and prostate cancer patients were assessed using alkaline comet assay after exposure to ⁶⁰Co gamma rays. Results: Results showed that higher levels of baseline and gamma rays induced DNA damage in leukocytes of prostate cancer cases than in controls. A similar dose response was obtained for both groups. After a repair time of 24 h following in vitro irradiation, samples from the healthy individuals showed no residual DNA damage in their leukocytes, whereas prostate cancer patients revealed more than 20%. Although similar initial radiosensitivity was observed for both groups, the repair kinetics of radiation induced DNA damage of leukocytes from prostate cancer cases and healthy subjects were statistically different. Conclusion: These results support the hypothesis that men affected by prostate cancer may have a constitutional genomic instability. Key Words: Leukocytes, DNA damage, Radiosensitivity, Prostate cancer, Comet assay     

Wicking phenomenon in polyacrylonitrile nanofiber yarn

The aim of this paper is to investigate vertical wicking in polyacrylonitrile (PAN) electrospinning nanofiber yarn using image analysis. Colored liquid rising phenomenon into the yarn and the distance of liquid rise were determined as a function of time. The kinetics of capillary rise follows the Lucas-Washburn equation. The results show that capillary rise rate coefficient is being reduced with increasing yarn twist, due to the reduction of continuity and size of capillaries. Increasing heat treatment stretch from 0 % (draw ratio=1) to 50 % (draw ratio=1.5) increases the capillary rise rate coefficient, due to the more homogeneity of capillary spaces in the yarn structure and increasing heat treatment stretch from 50 to 100 % (draw ratio=2) reduces capillary rise rate coefficient, because of the low capillary length. The present study indicates that an appropriate choice in production parameters of nanofiber yarn is all important in obtaining the desired properties of capillary rise.     

Chemical composition of oleo-gum-resin from Ferula gummosa

The chemical composition of oleo-gum-resin from Ferula gummosa collected in the northern part of Iran has been studied. The fraction of oleo-gum-resin soluble in ethanol (ca 67 wt.%) is composed by three major fractions: (i) monoterpenes and monoterpenoids (ca 15 wt.% fraction), (ii) sesquiterpenes and sesquiterpenoids (ca 30 wt.%) and (iii) triterpenes and triterpenoids (ca 55 wt.%). The major families of terpenes and terpenoids were identified employing gas chromatography coupled with mass spectrometry detector (GC-MS). Almost 25 wt.% of oleo-gum-resin was insoluble in ethanol and, according to wet chemistry analyses, assigned to arabinogalactane structurally associated with protein complex (AGP). This arabinogalactan possessed the molecular weight of ca 30 kDa, as revealed by size exclusion chromatography, and the main backbone was constituted by β-(1 → 3)/β-(1 → 3,6)-linked d-galactopyranosyl residues ramified predominantly by terminal α-l-arabinofuranosyl and β-d-glucuronopyranosyl residues, as assessed by 1D/2D ¹H NMR.     

Up-regulation of Endothelin-1 and Endothelin type A receptor genes expression in the heart of broiler chickens versus layer chickens

To compare Endothelin (ET) production and genes expression of ET-1 and ET_A receptor (ET_AR) between broiler and layer chickens during rearing, semi-quantitative RT-PCR and enzyme immunometric assay were performed in the heart ventricles and serum. There were gradual elevations of ET-1 and ET_AR mRNAs in the left ventricle of broiler and layer chicken groups that were mainly significant (P < 0.05) at 28, 35 and 42 days of age with compared to previous days whereas were not significant between two groups.These gradual elevations of ET-1 and ET_AR mRNAs were also observed in the right ventricle that were significant (P < 0.05) at 28, 35 and 42 days of age in broilers and 42 days of age in layers with compared to previous days. Increasing of these mRNAs in the right ventricle of broiler chickens were significantly (P < 0.05) more than layer chickens at 28, 35 and 42 days. Serum ET in broilers was significantly (P < 0.05) higher than layer chickens at 28 and 42 days of age. It is concluded that circulating ET and cardiac ET-1, ET_AR genes expression is higher in broiler chickens than in layer chickens particularly after 21 days of age. It is probably that these breed differences make broiler chickens to be more susceptible to Endothelin related-cardiomyopathies such as congestive heart failure and ascites.