scholarly journals The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica Species to High Concentration: Effects on Neutralization of Leaked Tank Wastes and Migration of Radionuclides in the Subsurface

2002 ◽  
Author(s):  
Andrew R Felmy ◽  
Gregory Choppin ◽  
David A Dixon
Keyword(s):  
High Concentration ◽  
Concentration Effects ◽  
And Migration ◽  
Complexation Reactions

scholarly journals Tuned S-Scheme Cu2S_TiO2_WO3 Heterostructure Photocatalyst toward S-Metolachlor (S-MCh) Herbicide Removal

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2231
Author(s):  
Alexandru Enesca ◽  
Luminita Isac
Keyword(s):  
Sol Gel ◽  
Annealing Treatment ◽  
Atomic Ratio ◽  
High Concentration ◽  
Step Procedure ◽  
Constant Rate ◽  
Efficient Charge ◽  
Crystallite Sizes ◽  
Oxygen Excess ◽  
And Migration

A dual S-scheme Cu2S_TiO2_WO3 heterostructure was constructed by sol–gel method using a two-step procedure. Due to the synthesis parameters and annealing treatment the heterostructure is characterized by sulfur deficit and oxygen excess allowing the passivation of oxygen vacancies. The photocatalytic activity was evaluated under UV and UV–Vis irradiation scenarios using S-MCh as reference pollutant. The heterostructure is composed on orthorhombic Cu2S, anatase TiO2 and monoclinic WO3 with crystallite sizes varying from 65.2 Å for Cu2S to 97.1 Å for WO3. The heterostructure exhibit a dense morphology with pellets and particle-like morphology closely combined in a relatively compact assembly. The surface elemental composition indicate that the heterostructure maintain a similar atomic ratio as established during the synthesis with a slight sulfur deficit due to the annealing treatments. The results indicate that the three-component heterostructure have higher photocatalytic efficiency (61%) comparing with two-component heterostructure or bare components. Moreover, Cu2S_TiO2_WO3 exhibit a superior constant rate (0.114 s−1) due to the high concentration of photogenerated charge carriers, efficient charge separation and migration.

scholarly journals Experimental Investigation of Water–Sand Mixed Fluid Initiation and Migration in Porous Skeleton during Water and Sand Inrush

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Xin Yang ◽  
Yong J. Liu ◽  
Ming Xue ◽  
Tian H. Yang ◽  
Bin Yang
Keyword(s):  
Structural Instability ◽  
Sand Particle ◽  
Incipient Motion ◽  
High Concentration ◽  
Sand Mixture ◽  
Porous Skeleton ◽  
Key Factor ◽  
Motion Characteristics ◽  
And Migration ◽  
Mixed Fluid

Water–sand inrush is one of the most serious disasters for mining in China. The evaluation of the occurrence and development of a high-concentration water and sand mixed fluid is an important issue for mining in China. In this study, contraposing to the 3 phases of water–sand inrush, three kinds of experiments are designed for the investigation of initiation, development, and occurrence of the disaster. A new sand–water transport testing system is setup to perform the tests. The results show that there are two key points in the disaster: (1) sand particle incipient motion and (2) porous skeleton structural instability. The incipient motion of sand grains is accompanied with the phenomena of volumetric dilatation and granular fluidization. The critical velocity of the incipient motion of the water–sand mixed fluid is significantly affected by the particle size and external stress. The interaction between water and sand grains is the key factor affecting the motion characteristics of water–sand mixture. When the hydraulic conditions exceed the threshold, the water and sand grains are mutually promoted, and the aquifer skeleton becomes unstable. Furthermore, during the water–sand inrush, the curves of volumetric flow rates of sand and water, respectively, for different samples manifest as two distinct waveforms.

Seasonal vertical distribution and diel migration of zooplankton in a temperate stratified lake

Biologia ◽  
2011 ◽  
Vol 66 (2) ◽  
Author(s):  
Evangelia Doulka ◽  
George Kehayias
Keyword(s):  
Vertical Distribution ◽  
Zooplankton Community ◽  
Abiotic Factor ◽  
High Concentration ◽  
Diel Migration ◽  
Four Seasons ◽  
Diel Vertical Migrations ◽  
Vertical Segregation ◽  
And Migration ◽  
The Vertical Distribution

AbstractThe investigation of the vertical distribution of the zooplankton community in the temperate Lake Trichonis during four seasons in 2005, showed the existence of vertical segregation among species, ontogenetic stages and sexes within and between the major groups. In each season, the two or three more abundant rotifer species distributed at separate depth layers, while this feature was maintained during the entire 24 h period, since no diel vertical migrations (DVM) were performed. In contrast, the crustacean community, comprised mainly by the calanoid copepod Eudiaptomus drieschi and the cladoceran Diaphanosoma orghidani, showed various patterns of DVM, being more pronounced in spring and summer. Females of E. drieschi distributed deeper than males, while the copepod nauplii were found mainly in the surface layer in all four seasons. Temperature was the most important abiotic factor affecting directly and indirectly the vertical distribution and migration of various species. During stratification, the metalimnion was the most productive layer in Lake Trichonis, having maximum values of dissolved oxygen and low transparency due to high concentration of organic matter and phytoplankton. The DVM patterns of the crustaceans indicate that the metalimnion acts probably as a daylight refuge against predation by Atherina boyeri, which is the dominant planktivorous fish in the lake.

Investigation of high concentration effects of Sb and P in silicon by combination of SIMS and TEM

1989 ◽  
Vol 333 (3) ◽  
pp. 191-202 ◽  
Author(s):  
G. Stingeder ◽  
P. Pongratz ◽  
W. Kuhnert ◽  
T. Brabec
Keyword(s):  
High Concentration ◽  
Concentration Effects

scholarly journals CXCL12 Modulates Prostate Cancer Cell Adhesion by Altering the Levels or Activities ofβ1-Containing Integrins

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Mehdi Dehghani ◽  
Sedigheh Kianpour ◽  
Ana Zangeneh ◽  
Zohreh Mostafavi-Pour
Keyword(s):  
Prostate Cancer ◽  
Cell Adhesion ◽  
Collagen I ◽  
Integrin Receptors ◽  
High Concentration ◽  
Kinase Activation ◽  
Potential Biomarker ◽  
Cell Adhesion And Migration ◽  
And Migration ◽  
Recombinant Fragments

The mechanisms by which prostate cancer (PCa) cell adhesion and migration are controlled during metastasis are not well understood. Here, we studied the effect of CXCL12 in PCa cell adhesion and spreading in DU145 and PC3 cell lines using as substrates collagen I, fibronectin (FN), and their recombinant fragments. CXCL12 treatment increasedβ1 integrin-dependent PC3 cell adhesion on FN which correlated with increased focal adhesion kinase activation. However neitherα5β1 norα4β1 subunits were involved in this adhesion. By contrast, CXCL12 decreased DU145 adhesion and spreading on FN by downregulatingα5 andβ1 integrin expression. To demonstrate the clinical relevance of CXCL12 in PCa, we measured CXCL12 levels in plasma by using ELISA and found that the chemokine is elevated in PCa patients when compared to controls. The high concentration of CXCL12 in patients suffering from PCa in comparison to those with benign disease or healthy individuals implicates CXCL12 as a potential biomarker for PCa. In addition these data show that CXCL12 may be crucial in controlling PCa cell adhesion on fibronectin and collagen I, possibly via crosstalk with integrin receptors and/or altering the expression levels of integrin subunits.

scholarly journals Biphasic Effect of Pirfenidone on Angiogenesis

2022 ◽  
Vol 12 ◽  
Author(s):  
Donghao Gan ◽  
Wenxiang Cheng ◽  
Liqing Ke ◽  
Antonia RuJia Sun ◽  
Qingyun Jia ◽  
...  
Keyword(s):  
Vascular Endothelial Cells ◽  
Tube Formation ◽  
Endothelial Cell Migration ◽  
High Concentration ◽  
Low Concentrations ◽  
Biphasic Effect ◽  
High Concentrations ◽  
And Migration ◽  
The Impact

Pirfenidone (PFD), a synthetic arsenic compound, has been found to inhibit angiogenesis at high concentrations. However, the biphasic effects of different PFD concentrations on angiogenesis have not yet been elucidated, and the present study used an in vitro model to explore the mechanisms underlying this biphasic response. The effect of PFD on the initial angiogenesis of vascular endothelial cells was investigated through a Matrigel tube formation assay, and the impact of PFD on endothelial cell migration was evaluated through scratch and transwell migration experiments. Moreover, the expression of key migration cytokines, matrix metalloproteinase (MMP)-2 and MMP-9, was examined. Finally, the biphasic mechanism of PFD on angiogenesis was explored through cell signaling and apoptosis analyses. The results showed that 10–100 μM PFD has a significant and dose-dependent inhibitory effect on tube formation and migration, while 10 nM–1 μM PFD significantly promoted tube formation and migration, with 100 nM PFD having the strongest effect. Additionally, we found that a high concentration of PFD could significantly inhibit MMP-2 and MMP-9 expression, while low concentrations of PFD significantly promoted their expression. Finally, we found that high concentrations of PFD inhibited EA.hy926 cell tube formation by promoting apoptosis, while low concentrations of PFD promoted tube formation by increasing MMP-2 and MMP-9 protein expression predominantly via the EGFR/p-p38 pathway. Overall, PFD elicits a biphasic effect on angiogenesis through different mechanisms, could be used as a new potential drug for the treatment of vascular diseases.

scholarly journals Experimental Study on the Fine-Grained Uranium Tailings Reinforced by MICP

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Rong Gui ◽  
Yu-xiang Pan ◽  
De-xin Ding ◽  
Yong Liu ◽  
Zhi-jun Zhang
Keyword(s):  
Discharge Rate ◽  
Physiological Activity ◽  
Friction Angle ◽  
Solution Concentration ◽  
High Concentration ◽  
Sand Column ◽  
Sporosarcina Pasteurii ◽  
Fine Grained ◽  
And Migration ◽  
Uranium Tailings

Sporosarcina Pasteurii was chosen for the experiment to study the effect and mechanism of fine-grained uranium tailings reinforced by MICP. The biochemical characteristics of strains and microbial immobilization in uranium tailings were analyzed. The results showed that the CaCO3 production rate is positively correlated with the physiological activity of Sporosarcina Pasteurii and the concentration of calcium sources, and the higher the solution concentration of CaCl2, the lower the discharge rate of bacterial liquid from the sand column, but high concentration of CaCl2 solution will affect the uniform distribution and migration of bacteria in the uranium tailings. After 16 days, the direct shear was used to test the reinforcement effects of fine-grained uranium tailings by MICP. The cohesive force and the internal friction angle of fine-grained uranium tailings were increased by 140.1% and 46.7%. The production amount of CaCO3 is 138.89 kg/m3. The results showed that the MICP-reinforced technology can effectively improve the shear strength of the uranium tailings, and the experiment provides a new method for the reinforcement of the fine-grained uranium tailings dam.

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