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Field experiments were conducted in Iran in order to determine the interactions between the tillage system and crop rotation on weed seedling populations and crop yields from 2002 to 2005. No tillage, shallow tillage and deep tillage were the main plots and three crop sequences comprising continuous wheat (W‐W), wheat–canola–wheat–canola (C‐W) and wheat–safflower–wheat–safflower (S‐W) were the subplots. Bromus japonicus, Carthumus lanatus, Polygonum aviculare, Lolium temulentum and Avena ludoviciana were found to be the dominant species. The initial weed population in 2002 was estimated at 65 seedlings per m2 and B. japonicus (~35 seedlings per m2) was the most abundant species, followed by A. ludoviciana and L. temulentum. The dominant weed species mostly did not favor the combination of S‐W and C‐W with any tillage type. For the B. japonicus population, S‐W in combination with moldboard plowing indicated the lowest seedling population. In conclusion, the crop sequence in combination with tillage would help to control troublesome weed species. Safflower and canola were determined to be effective in reducing the grass weeds. The inclusion of these crops in rotation also increased the total revenue of the cropping systems because of the higher sale price of canola and safflower.  相似文献   
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Analytical scale chemical/cultivation profiling prioritized the Australian marine-derived fungus Aspergillus noonimiae CMB-M0339. Subsequent investigation permitted isolation of noonindoles A–F (5–10) and detection of eight minor analogues (i–viii) as new examples of a rare class of indole diterpene (IDT) amino acid conjugate, indicative of an acyl amino acid transferase capable of incorporating a diverse range of amino acid residues. Structures for 5–10 were assigned by detailed spectroscopic and X-ray crystallographic analysis. The metabolites 5–14 exhibited no antibacterial properties against G-ve and G+ve bacteria or the fungus Candida albicans, with the exception of 5 which exhibited moderate antifungal activity.  相似文献   
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Monitoring exchangeable sodium percentage (ESP) and sodium adsorption ratio (SAR) variability in soils is both time-consuming and expensive. However, in order to estimate the amounts of amendments and land management, it is essential to know ESP and SAR variations and values in sodic or saline and sodic soils. Thus, presenting a method which uses easily obtained indices to estimate ESP and SAR indirectly is more optimal and economical. Input data of the current research were 189 soil samples collected based on a regular networking approach from Miankangi region, Sistan plain, Iran. Then, their physicochemical properties were measured. Results showed that SAR = 3.8 × ln(EC) + 22.83 × ln(pH) – 44.37, (R2 = 0.63), and ESP = 3.98×ln(EC) + 36.88(pH) – 56.98 (R2 = 0.78) are the best regression models for estimating SAR and ESP, respectively. Moreover, multilayer perceptron (MLP), which explains 95–97% of parameters of soil sodicity using EC and pH as inputs, was the best neural network model. Therefore, MLP could be applied for ESP and SAR evaluation with high accuracy in the Miankangi region.  相似文献   
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Ultraviolet (UV) B exposure is a prominent cause of skin aging and a contemporary subject of interest. The effects are progressing through the generation of reactive oxygen species (ROS) that alter cell signaling pathways related to inflammatory responses. The present study evaluates the protective effects of (7aR)-6-hydroxy-4,4,7a-trimethyl-6,7-dihydro-5H-1-benzofuran-2-one (HTT) isolated from the edible brown algae Sargassum horneri against UVB protective effects in human dermal fibroblasts (HDFs). HTT treatment dose-dependently suppressed intracellular ROS generation in HDFs with an IC50 of 62.43 ± 3.22 µM. HTT abated UVB-induced mitochondrial hyperpolarization and apoptotic body formation. Furthermore, UVB-induced activation of key nuclear factor (NF)-κB and mitogen-activated protein kinase signaling proteins were suppressed in HTT treated cells while downregulating pro-inflammatory cytokines (interleukin-1β, 6, 8, 33 and tumor necrosis factor-α). Moreover, HTT treatment downregulated matrix metalloproteinase1, 2, 3, 8, 9 and 13 that was further confirmed by the inhibition of collagenase and elastase activity. The evidence implies that HTT delivers protective effects against premature skin aging caused by UVB exposure via suppressing inflammatory responses and degradation of extracellular matrix (ECM) components. Extensive research in this regard will raise perspectives for using HTT as an ingredient in UV protective ointments.  相似文献   
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