Fabrication of Biocompatible PLGA/PCL/PANI Nanofibrous Scaffolds with Electrical Excitability

Application of electrospun nanofibrous scaffolds has received immense attention in tissue engineering. Fabrication of scaffolds with appropriate electrical properties plays a key role in neural tissue engineering. Since fibers orientation in the scaffolds affects the growth and proliferation of the cells, this study aimed to prepare aligned electrospun conductive nanofibers by mixing 1 %, 10 % and 18 % (w/v) doped polyaniline (PANI) with polycaprolactone (PCL)/poly lactic-coglycolic acid (PLGA) (25/75) solution through the electrospinning process. The fibers diameter, hydrophilicity and conductivity were measured. In addition, the shape and proliferation of the nerve cells seeded on fibers were evaluated by MTT cytotoxicity assay and scanning electron microscopy. The results revealed that the conductive nanofibrous scaffolds were appropriate substrates for the attachment and proliferation of nerve cells. The electrical stimulation enhanced neurite outgrowth compared to those PLGA/PCL/PANI scaffolds that were not subjected to electrical stimulation. As polyaniline ratio increases, electric stimulation through nanofibrous PLGA/PCL/PANI scaffolds results in cell proliferation enhancement. However, a raise more than 10 % in polyaniline will result in cell toxicity. It was concluded that conductive scaffolds with appropriate ratio of PANI along with electrical stimulation have potential applications in treatment of spinal cord injuries.     

Effect of dietary Spirulina platensis on fatty acid composition of rainbow trout (Oncorhynchus mykiss) fillet

This paper reports on inclusion of Spirulina platensis (SP) in rainbow trout (Oncorhynchus mykiss) fish diet and its effect on the fish tissue fatty acids (FAs) composition. Fish in triplicate groups with average initial body weight of 75 ± 0.23 g and age of about 7 months were fed a control diet with no supplements and with three experimental diets supplemented with 2.5, 5 and 7.5 weight percent (wt%) of SP for 12 weeks. At the end of experiment, the fillet FA compositions were evaluated. It was found that the composition of FAs in fish fillet was significantly (P < 0.05) affected by inclusion of SP in diets. As compared to the control sample, feeding the fish supplemented particularly with low levels of SP improved the quality of FAs by decreasing undesirable saturated FAs (SFAs) content from 20.03 to 17.93 % and increasing the level of some beneficial long-chain highly unsaturated FAs namely eicosapentaenoic acid (C20:5 n-3) from 6.47 to 7.27 %, docosapentaenoic acid (C22:5 n-3) from 1.42 to 1.56 % and docosahexaenoic acid (C22:6 n-3) from 1.26 to 1.35 %. Further increase in the SP inclusion level generally did not lead to desirable results. The SP inclusion in the fish diet had no significant impact on overall contents of n-3 and n-6 polyunsaturated FAs in fish fillet. However, the total highly unsaturated FAs (HUFAs) and n-3 HUFAs levels, UFAs/SFAs ratio and n-3/n-6 index were increased from 11.25, 10.65, 3.98 and 0.57 to 12.13, 11.56, 4.40 and 0.62 %, respectively, as a result of 5 wt% SP loading. In general, it can be concluded that SP inclusion up to 5 wt% of loading in rainbow trout culture can be beneficial in terms of FAs compositions of the fish fillet.     

Effects of neonatal diarrhea and other conditions on subsequent productive and reproductive performance of heifer calves

Diarrhea is one of the most frequent diseases of neonatal calves in dairy herds. The aim of this study was to evaluate the effects of neonatal diarrhea and other conditions on subsequent first lactation milk production and reproductive performance of heifer calves up to the first calving. Seven hundred heifer calves (350 with and 350 without the history of diarrhea in first month of life) were monitored from birth until a year after calving. For each heifer, birth season, birth weight, ease of birth and occurrence of diseases from birth to the end of first lactation were recorded as independent variables. Interval from birth to first service, interval from birth to conception, interval from birth to first calving and 305-days milk yield in the first lactation were recorded as dependent variables. Effects of explanatory variables on productive and reproductive indices were evaluated by survival analysis and general linear model. Heifers with the history of diarrhea during the first month of their lives showed lower daily hazard of conception [Hazard ratio: 0.85 (95%CI: 0.73–0.99)] and calving [Hazard ratio: 0.84 (95%CI: 0.72–0.98)] than those of healthy heifers. Subsequent reproductive performance of heifer calves was also associated with birth season and ease of birth. Further, heifer calves born with birth weight of below 35 kg produced an average of 518 and 506 l less milk in their first lactation compared to calves with a birth weight 40–45 (p = 0.013) and greater than 45 kg (P = 0.033), respectively. These findings showed that occurrence of neonatal diarrhea and other neonatal parameters are associated with harmful effects on subsequent production and reproductive performance.     

Estimation of the organic carbon content by the pattern recognition method

Studying the status of agricultural soils is one of the most important concerns in the agricultural sector. The soil organic carbon (SOC) is one of the main parameters and it plays an important role in improving soil properties. Hence, knowing this parameter is important in soil science. This study applied the pattern recognition (PR) method in predicting the SOC. Also, the ability of this method was compared with different methods such as the Radial Basis Function Network (RBF), Multilayer Perceptron Neural Network (MLP), Multiple Linear Regression (MLR) and Support Vector Regression (SVR). To compare the results, four performance criteria, namely, root mean square errors (RMSE), the Nash–Sutcliffe efficiency (NS), Willmott’s Index of agreement (WI), mean absolute error (MAE) and Taylor diagrams were used. Results indicated that the PR model performed significantly better than the MLP, MLR, SVR, and RBF models for the estimation of the SOC.     

Antioxidant activity of Erica arborea

The antioxidant properties of the methanol extract of leaves and flowers of Erica arborea and the ethyl acetate, butanol and water soluble fractions were investigated. The ethyl acetate extract was found to be the richest for phenolic and flavonoid content which showed the highest antioxidant activity.     

Physiological characteristics and irrigation water productivity of quinoa (Chenopodium quinoa Willd.) in response to deficit irrigation imposed at different growing stages—A field study from Southern Iran

Iran has been faced to drought during last decades, and one way to overcome this phenomenon is to improve the water productivity by introducing new crops tolerant to water stresses such as quinoa. Two-year field experiment was performed to find out the response of quinoa (cv. Titicaca) to deficit irrigation imposed at different growing stages. Hence, the effect of full irrigation (100% irrigation water requirement) and deficit irrigation (50% full irrigation) on physiological parameters, yield, irrigation water productivity and root density of quinoa was investigated during 2016 and 2017 growing seasons. The result showed that there was a significant difference between all variables in two years. Higher average air temperature in 2017 (2.0°C) resulted in a reduction of seed yield and water productivity (55% and 40% of that obtained in 2016, respectively). Application of deficit irrigation during different growing stages reduced crop height, stomatal conductance and seed yield, while it increased the root length density in both years. In conclusion, flowering stage of quinoa was very sensitive to deficit irrigation, and irrigation at grain filling stage would not help to recover the seed yield. Furthermore, the seed yield was lower than that obtained in other studies performed in other countries using same quinoa cultivar, which could be due to higher amount of applied irrigation water and different phenology under different climatic conditions. A decision on cultivating this crop under semi-arid conditions has to be made considering limited water resources.     

Soil seed banks in the Arasbaran Protected Area of Iran and their significance for conservation management

The Arasbaran Protected Area is an important but little studied nature reserve in NW Iran. In the past habitat heterogeneity and biodiversity have been threatened by over-exploitation; in the future depopulation may lead to partial abandonment. The soil seed bank was examined to see whether there are sufficient species represented as persistent seeds to reconstitute the vegetation in the event of habitat deterioration. There were differences between seed banks from different soils and vegetation types but essentially all soil seed banks contained few species and low densities of seed. Moreover, the species in the seed bank were unrepresentative of the vegetation. During future periods of changing land use it will be important to maintain the existing vegetation. There are however indications of successful recent conservation management. Annuals are abundant in the woodland seed bank but absent from the vegetation. The forest is recovering from the disturbance of collecting fire-wood.     

EFFECTS OF PHYTOHORMONES ON PROLINE CONTENT AND ANTIOXIDANT ENZYMES OF VARIOUS WHEAT CULTIVARS UNDER SALINITY STRESS

Salinity stress is one of the important agricultural problems in the world. A factorial experiment based on completely randomized design with four replications was conducted to evaluate the effects of phytohormones (gibberellic acid and abscisic acid) on the activity of antioxidant enzymes (peroxidase, superoxide dismutase and catalase), rubisco activity and content, and proline in three wheat cultivars (Gascogen, Zagros, and Kuhdasht) under control and salinity stress (3.5 and 7 dS m^?1). The results showed that salinity stress (3.5 and 7 dS m^?1) decreased the activity of catalase, rubisco, carboxylase, but increased peroxidase, superoxide dismutase activity and proline content. Gibberellic acid caused 58.03% increased in rubisco carboxylase activity in Zagros at 7 dS m^?1 in comparison with abscisic acid under salinity stress compared with the control plants in Kuhdasht. Activity of superoxide dismutase in Kuhdasht cultivar at 7 dS m^?1 salinity level showed 76.43% increased in Gascogen under salinity stress compared with the control plants with gibberellic acid application. The highest proline content as an osmolyte was found in Zagros at 7 dS m^?1 salinity level with abscisic acid (194 μmol g^?1 DM) application. Peroxidase activity increased 83.31% and catalase activity decreased 61.27% compared with the control plants in Zagros. Gibberellic acid application significantly prevented reduction in rubisco content under salinity stress. In conclusion, increased in peroxidase and superoxide dismutase activity and proline content decreased the adverse effects of salinity stress on studied cultivars. Also, the foliage spray of gibberellic acid enhanced and improved the growth condition. In this experiment, Zagros cultivar showed more tolerance to salinity stress than the other two cultivars.