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Soil biodiversity includes organisms which spend a part or all of their life cycle on or in the soil. Among soil-dwelling animals, macro-fauna as an important group of animals have important effects on the dynamics of soil organic matter and litter decomposition process. The humus forms interact with the climatic conditions, flora, as well as soil fauna, and microbial activity. In new humus form classifications, soil organisms play an important role in separation of humus horizons from one another. The subject of this study was to determine the diversity of macro fauna for different humus forms. We determined humus forms using morphological classification, and then 69 random samples were taken from plots of 100 cm2 in area, and soil macro-fauna species were collected by hand sorting method. Two classes of humus forms, including Mull (with three humus orders, namely Dysmull, Oligomull, and Mesomull,) and Amphi (with four humus orders, namely Leptoamphi, Eumacroamphi, Eumesoamphi, and Pachyamphi) were identified. A number of 13 macro-fauna orders were identified using identification key. Among the humus orders, Shannon diversity, Simpson evenness and Margalef richness indices were the highest in Pachyamphi order. Arthropod diversity in Pachyamphi humus order was higher than those of Mull. These results showed that diversity of soil macrofauna increase by increasing the thickness of the organic horizons (OL, OF, OH), especially OH horizon.  相似文献   
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In the current paper, we fabricated, characterized, and applied nanocomposite hydrogel based on alginate (Alg) and nano-hydroxyapatite (nHA) loaded with phenolic purified extracts from the aerial part of Linum usitatissimum (LOH) as the bone tissue engineering scaffold. nHA was synthesized based on the wet chemical technique/precipitation reaction and incorporated into Alg hydrogel as the filler via physical cross-linking. The characterizations (SEM, DLS, and Zeta potential) revealed that the synthesized nHA possess a plate-like shape with nanometric dimensions. The fabricated nanocomposite has a porous architecture with interconnected pores. The average pore size was in the range of 100–200 µm and the porosity range of 80–90%. The LOH release measurement showed that about 90% of the loaded drug was released within 12 h followed by a sustained release over 48 h. The in vitro assessments showed that the nanocomposite possesses significant antioxidant activity promoting bone regeneration. The hemolysis induction measurement showed that the nanocomposites were hemocompatible with negligible hemolysis induction. The cell viability/proliferation confirmed the biocompatibility of the nanocomposites, which induced proliferative effects in a dose-dependent manner. This study revealed the fabricated nanocomposites are bioactive and osteoactive applicable for bone tissue engineering applications.  相似文献   
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Irrigation and nitrogen management are two of the most important factors affecting production efficiency and environmental quality in potato cropping systems. Field studies were conducted in 1990 and 1991 to determine the interactive effects of irrigation amount and N timing on potato yield, quality and nitrate leaching potential. Sprinkler irrigation was applied at approximately 1.0, 1.2 or 1.4 times estimated evapotranspiration (ET) to Russet Burbank potatoes grown on a silt loam soil. Following tuber initiation, a total of 132 kg N/ha was applied through the irrigation system to N treatment subplots using either six weekly 22 kg N/ha applications or 3 biweekly 44 kg N/ha applications. Excessive irrigation reduced root zone and petiole NO3-N concentrations during substantial portions of the tuber bulking period. Biweekly 44 kg N/ha applications in 1991 produced higher and more consistent earlyseason root zone NO3-N concentrations in the 1.2 and 1.4 ET plots than did the weekly 22 kg N/ha applications. Late-season tuber dry weight, total plant dry weight and plant N uptake were not affected by irrigation rate or N timing. However, excessive irrigation reduced U.S. No. 1 yield and yield of tubers >284 g in both 1990 and 1991 and reduced total yield in 1990. Biweekly N applications produced higher U.S. No. 1 yields than weekly N applications at all irrigation levels. Excessive irrigation also reduced NO3-N remaining in the top 60 cm of soil at the end of the growing season. These results show that irrigating at optimal rates and applying split N at two week intervals on a silt loam soil can maximize Russet Burbank yield and quality while minimizing NO3-N losses.  相似文献   
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Background: Initial studies have shown that low-energy ultrasound stimulates living tissue cells to reduce regeneration or speed up their recovery. The purpose of this study was to examine the effects of various ultrasound parameters on the speed of recovery in injured sciatic nerves NMRI.Methods: NMRI mice (n = 200) with injured left paw, caused by crushing their sciatic nerves, were randomly selected. The animals were exposed to ultrasound radiation with various frequencies, intensities, and exposure time. They were allocated into 20 groups (19 treatment and 1 control groups). Sciatic functional index (SFI) test was used to evaluate the difference between the groups with respect to functional efficiency of the sciatic nerve and its recovery. SFI ، (P=0.000).Results: The results of SFI test obtained from the 14th day showed a significant difference among the groups (P<0.05). On the 14th day after treatment, one of the groups (US11) recovered up to 90%..Conclusion: Altered ultrasound exposure parameters had more favorable outcomes compared with our previous work.Key Words: Sciatic nerve, Ultrasonic therapy, Regeneration  相似文献   
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An experiment with factorial arrangement of treatments on a randomized complete block (RCB) design basis with three replications was conducted in a greenhouse during Spring 2010 to investigate changes in sodium ion (Na+), potassium ion (K+), Na+/K+ and to determine proline, protein content, and superoxide dismutase (SOD) of four wheat and four barley cultivars. Three salt levels {1, control (no salt), 7, and 13 dS m?1 [2.5 and 5 g salt [sodium chloride (NaCl) and sodium sulfate (Na2SO4) in 1:1 ratio] per kg of soil, respectively]} were used in this investigation. Salt stress treatments were applied 4 weeks after planting (at 2 leaf stage). Leaf samples were taken four weeks after imposition of salt treatment. The results showed that salinity caused an increased in proline and protein content, and SOD in all wheat and barley cultivars. The highest proline and protein content of barley and wheat cultivars at all salinity levels were observed in ‘Nimrooz’ and ‘Bam’ cultivars, respectively. At all salinity levels, wheat and barley cultivars ‘Kavir’ and ‘Nimrooz’, respectively, had the lowest Na+ content. Barley cultivar ‘Kavir’ and wheat cultivar ‘Bam’ had higher K+ and K+:Na+ ratios. This might be related to salt tolerance in these two cultivars. Wheat and barley cultivars showed differences with regard to proline, protein, and SOD content, Na+, K+, and K+:Na+ ratio, indicating existence of genetic diversity among the cultivars. These findings indicated that higher K+, K+:Na+ ratio, proline, protein, and SOD content could be the key factors, which offer advantage to barley over wheat for superior performance under saline conditions.  相似文献   
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Bread staling involves a combination of physico-chemical phenomena that leads to a reduction of quality. This study aims at evaluating the impact of baking conditions (280 °C, 8 min; 310 °C, 5.5 min; 340 °C, 4 min), baking type (of fully baked (FB) and part-baked (PB)) and storage temperature (−18, 4 and 20 °C) on the staling of Sangak bread. Results showed that lower baking temperature with longer baking time produced drier bread with higher firmness. In FB Sangak breads, amylopectin retrogradation, amount of unfreezable water and firmness (measured by compression test) increased during storage at positive temperatures but hardness (determined by Kramer shear test) decreased significantly during first day of storage. The recrystallized amylopectin traps the free water resulting in crumb hardening. Water is also absorbed by the dry crust resulting in changes of rheological properties in the crust and crumb, and finally in staling. Storage at 4 °C resulted in increasing melting enthalpy of amylopectin crystallite in comparison with storage at 20 °C. Also it was found that firmness of PB breads due to rebaking was significantly lower than FB breads. There were no significant changes in staling parameters of FB and PB stored at −18 °C.  相似文献   
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