Evaluation of metals that are potentially toxic to agricultural surface soils, using statistical analysis, in northwestern Saudi Arabia

© 2015, Springer-Verlag Berlin Heidelberg. Heavy metals in agricultural soils enter the food chain when taken up by plants. The main purpose of this work is to determine metal contamination in agricultural farms in northwestern Saudi Arabia. Fifty surface soil samples were collected from agricultural areas. The study focuses on the geochemical behavior of As, Cd, Co, Cr, Cu, Hg, Pb and Zn, and determines the enrichment factor and geoaccumulation index. Multivariate statistical analysis, including principle component analysis and cluster analysis, is also applied to the acquired data. The study shows considerable variation in the concentrations of the analyzed metals in the studied soil samples. This variation in concentration is attributed to the intensity of agricultural activities and, possibly, to nearby fossil fuel combustion activities, as well as to traffic flows from highways and local roads. Multivariate analysis suggests that As, Cd, Hg and Pb are associated with anthropogenic activities, whereas Co, Cr, Cu and Zn are mainly controlled by geogenic activities. Hg and Pb show the maximum concentration in the analyzed samples as compared to the background concentration

Waveform dissimilarity factor-based protection for main transformers in wind farms

Current differential protection (CDP) is widely used as main protection for transformers due to its high reliability and selectivity. Owing to non-fundamental frequency current, magnetizing inrush and current transformer (CT) saturation, CDP may undergo slow operating speed when the internal fault occurs. When the external fault occurs, CDP may false operate. Furthermore, given the disadvantage of Hausdorff distance being extremely sensitive to abnormal data, a new metric that reveals the dissimilarity degree of two waveforms is presented, namely waveform dissimilarity factor (WDF). WDF has inherent immunity to abnormal data. Subsequently, WDF-based protection for main transformer is proposed herein. In order to reduce the adverse effects of magnetizing inrush and CT saturation and accurately identify internal faults, the reward and punishment mechanism is designed. The protection principle is elaborated and its operating characteristics are analyzed under various conditions. Finally, by constructing the DFIG-based wind farm, PSCAD is used to verify the advantages of the novel protection algorithm based on WDF. Its performance is widely assessed in various scenarios in detail, including magnetizing inrushes, minor and server internal faults, inter-turn fault, turn-to-ground fault, internal fault with CT saturation and external fault with CT saturation, data loss, abnormal data, and CT error. The results show that the novel protection scheme has the characteristics of fast, secure, and robust

miR-145 Inhibits Lung Adenocarcinoma Stem Cells Proliferation by Targeting OCT4 Gene

Background and objective MiR-145 functions as a protective miRNA identified in tumor tissues of lung adenocarcinoma patients. The aim of this study is to investigate the relationship between miR-145 and proliferation of lung cancer stem cells and involved molecular mechanisms in human lung adenocarcinaoma A549 cell line. Methods MicroRNA microarray technology was conducted to compare miRNA signature between tumor and adjacent normal tissue of lung adenocarcinaoma. The potential target gene of miR-145 was predicted by online bioinformatic softwares. Pre-miR-145 mimics and anti-miR-145 inhibitor were transfected into A549 cell line by lipofectamine 2000. miR-145 expression in each group was detected by real time PCR. The OCT4 protein level was analyzed by Western blot. The predicted miR-145 binding site in OCT4 3’-untranslated region (UTR) was validated by dual-luciferase reporter gene assay. CCK-8 assay was employed to observe the proliferation activity of A549 cells. The ratio of CD133 positive cells in each group was analyzed by flow cytometry. Results miR-145 expression was significantly down-regulated in lung adenocarcinoma compared with ajacent normal tissue. OCT4 is a potential target gene of miR-145 predicted by miRanda. Compared with control group, miR-145 was significantly up-regulated and down-regulated in the pre-miR-145 mimics and anti-miR-145 inhibitor groups respectively. Overexpression of miR-145 inhibited the proliferation of A549 cells. Both the OCT4 protein level and CD133 positive ratio were remarkably decreased in the pre-miR-145 mimics group, whereas significantly increased in the anti-miR-145 inhibitor group. Dual-luciferase reporter gene assay validated the predicted miR-145 binding site of OCT4 3’UTR. Conclusion MiR-145 can inhibit the proliferation of lung cancer stem cells in A549 cell line via down-regulating OCT4 expression. MiR-145 is a potential protective miRNA of lung cancer

Lentinan confers protection against type 1 diabetes by inducing regulatory T cell in spontaneous non-obese diabetic mice

Abstract Background Lentinan (LNT) is a complex fungal component that possesses effective antitumor and immunostimulating properties. However, there is a paucity of studies regarding the effects and mechanisms of LNT on type 1 diabetes. Objective In the current study, we investigated whether an intraperitoneal injection of LNT can diminish the risk of developing type 1 diabetes (T1D) in non-obese diabetic (NOD) mice and further examined possible mechanisms of LNT’s effects. Methods: Pre-diabetic female NOD mice 8 weeks of age, NOD mice with 140–160 mg/dL, 200–230 mg/dL or 350–450 mg/dL blood glucose levels were randomly divided into two groups and intraperitoneally injected with 5 mg/kg LNT or PBS every other day. Then, blood sugar levels, pancreas slices, spleen, PnLN and pancreas cells from treatment mice were examined. Results Our results demonstrated that low-dosage injections (5 mg/kg) of LNT significantly suppressed immunopathology in mice with autoimmune diabetes but increased the Foxp3+ regulatory T cells (Treg cells) proportion in mice. LNT treatment induced the production of Tregs in the spleen and PnLN cells of NOD mice in vitro. Furthermore, the adoptive transfer of Treg cells extracted from LNT-treated NOD mice confirmed that LNT induced Treg function in vivo and revealed an enhanced suppressive capacity as compared to the Tregs isolated from the control group. Conclusion LNT was capable of stimulating the production of Treg cells from naive CD4 + T cells, which implies that LNT exhibits therapeutic values as a tolerogenic adjuvant and may be used to reverse hyperglycaemia in the early and late stages of T1D

High Oxygen Reduction Reaction Performances of Cathode Materials Combining Polyoxometalates, Coordination Complexes, and Carboneous Supports

A series of carbonaceous-supported precious-metal-free polyoxometalate (POM)-based composites which can be easily synthesized on a large scale was shown to act as efficient cathode materials for the oxygen reduction reaction (ORR) in neutral or basic media via a four-electron mechanism with high durability. Moreover, exploiting the versatility of the considered system, its activity was optimized by the judicious choice of the 3d metals incorporated in the {(PW₉)₂M₇} (M = Co, Ni) POM core, the POM counterions and the support (thermalized triazine-based frameworks (TTFs), fluorine-doped TTF (TTF-F), reduced graphene oxide, or carbon Vulcan XC-72. In particular, for {(PW₉)₂Ni₇}/{Cu­(ethylenediamine)₂}/TTF-F, the overpotential required to drive the ORR compared well with those of Pt/C. This outstanding ORR electrocatalytic activity is linked with two synergistic effects due to the binary combination of the Cu and Ni centers and the strong interaction between the POM molecules and the porous and highly conducting TTF-F framework. To our knowledge, {(PW₉)₂Ni₇}/{Cu­(ethylenediamine)₂}/TTF-F represents the first example of POM-based noble-metal-free ORR electrocatalyst possessing both comparable ORR electrocatalytic activity and much higher stability than that of Pt/C in neutral medium