Extraction of phosphorus from metallurgical grade silicon using a combined process of Si-Al-Ca solvent refining and CaO-CaF 2 slag treatment

Abstract(#br)A combined purification process of Si-Al-Ca solvent refining and CaO-CaF 2 slag treatment was investigated with a focus on removing phosphorus (P) from metallurgical-grade Si (MG-Si). The primary precipitates in the slag-treated Si-Al-Ca alloy are CaAl 2 Si 2 and CaSi 2 , and these precipitates can be eliminated via leaching with HCl + CH 3 COOH and HCl + HF in sequence. Compared to MG-Si, a higher extraction efficiency of P was achieved with Si-Al-Ca alloy after CaO-CaF 2 slag treatment. Influences of alloy composition, slag components, and operation parameter on the P removal efficiency were studied systematically. The optimal dephosphorization efficiency reached 98.6% when the 70%Si-Al-Ca alloy was treated with 20%CaO–80%CaF 2 slag twice. Furthermore, the mechanism of P removal using the combined process was studied. The results indicate that the Si-Al-Ca solvent refining causes the segregation coefficient of P to be lower, thus facilitating its mass transfer in slag treatment. A large amount of P was reduced and then diffused to the slag phase in the slag experiment. Residual P in the slag-treated alloy was trapped by the CaAl 2 Si 2 phase and was then removed via acid leaching

Development of dual-drug-loaded stealth nanocarriers for targeted and synergistic anti-lung cancer efficacy

Combination chemotherapy is widely exploited for suppressing drug resistance and achieving synergistic anticancer efficacy in the clinic. In this paper, the nanostructured targeting methotrexate (MTX) plus pemetrexed (PMX) chitosan nanoparticles (CNPs) were developed by modifying methoxy polye (thylene glycol) (mPEG), in which PEGylation CNPs was used as stealth nanocarriers (PCNPs) and MTX was employed as a targeting ligand and chemotherapeutic agent as well. Studies were undertaken on human lung adenocarcinoma epithelial (A549) and Lewis lung carcinoma (LLC) cell lines, revealing the anti-tumor efficacy of nanoparticle drug delivery system. The co-delivery nanoparticles (MTX-PMX-PCNPs) had well-dispersed with sustained release behavior. Cell counting kit-8 (CCK8) has been used to measure A549 cell viability and the research showed that MTX-PMX-PCNPs were much more effective than free drugs when it came to the inhibition of growth and proliferation. Cell cycle assay by flow cytometry manifested that the MTX-PMX-PCNPs exhibited stronger intracellular taken up ability than free drugs at the same concentration. In vivo anticancer effect results indicated that MTX-PMX-PCNPs exhibited a significantly prolong blood circulation, more tumoral location accumulation, and resulted in a robust synergistic anticancer efficacy in lung cancer in mice. The results clearly demonstrated that such unique synergistic anticancer efficacy of co-delivery of MTX and PMX via stealth nanocarriers, providing a prospective strategy for lung cancer treatment

Novel Co3O4 Nanoparticles/Nitrogen-Doped Carbon Composites with Extraordinary Catalytic Activity for Oxygen Evolution Reaction (OER)

Abstract Herein, Co3O4 nanoparticles/nitrogen-doped carbon (Co3O4/NPC) composites with different structures were prepared via a facile method. Structure control was achieved by the rational morphology design of ZIF-67 precursors, which were then pyrolyzed in air to obtain Co3O4/NPC composites. When applied as catalysts for the oxygen evolution reaction (OER), the M-Co3O4/NPC composites derived from the flower-like ZIF-67 showed superior catalytic activities than those derived from the rhombic dodecahedron and hollow spherical ZIF-67. The former M-Co3O4/NPC composite displayed a small over-potential of 0.3 V, low onset potential of 1.41 V, small Tafel slope of 83 mV dec−1, and a desirable stability. (94.7% OER activity was retained after 10 h.) The excellent performance of the flower-like M-Co3O4/NPC composite in the OER was attributed to its favorable structure

The big-fish-little-pond effect in China

Recent research has distinguished between the components of competency and affect in students' academic self-concept. The competency component operates on the basis of a comparison with peers. This comparison may lead to a big-fish-little-pond (BFLP) effect. To investigate the sustainability of the BFLP effect, a sample of 7th graders from 6 classes in a high school in China was surveyed on both the competency and affect components of school self-concept (N = 295) at the beginning, in the middle and by the end of grade 7 and compared across 4 groups categorised according to their high school entrance exam scores. Analysis of variance results showed that the highest scoring students had the highest self-concept of competency and the scores remained high throughout the year of 7th grade. In essence, the "big fish" remained big and the "small fish" remained small, and the pattern was consistent over time. The scores for the component of affect did not differ across groups, became slightly higher in mid-year, and remained high throughout the year. Instead of attempting to promote a positive affect in schooling, there seems to be a stronger need for enhancing a sense of competency in the "smaller fish"

Methotrexate-Loaded PEGylated Chitosan Nanoparticles: Synthesis, Characterization, and in Vitro and in Vivo Antitumoral Activity

key jointed Foundation of the National Science Foundation of China-Yunnan [U1137601]Cancer nanotherapeutics are rapidly progressing and being implemented to solve several limitations of conventional drug delivery systems. In this paper, we report a novel strategy of preparing methotrexate (MTX) nanopartides based on chitosan (CS) and methoxypoly(ethylene glycol) (mPEG) used as nanocarriers to enhance their targeting and prolong blood circulation. MTX and mPEG-conjugated CS nanopartides (NPs) were prepared and evaluated for their targeting efficiency and toxicity in vitro and in vivo. The MTX-mPEG-CS NP size determined by dynamic light scattering was 213 +/- 2.0 nm with a narrow particle size distribution, and its loading content (LC %) and encapsulation efficiency (EE) were 44.19 +/- 0.64% and 87.65 +/- 0.79%, respectively. In vitro release behavior of MTX was investigated. In vivo optical imaging in mice proved that MTX was released from particles subsequently and targeted to tumor tissue, showing significantly prolonged retention and specific selectivity. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay obviously indicated that the higher inhibition efficiency of MTX-mPEG-CS NPs meant that much more MTX was transferred into the tumor cells. A significant right-shift in the flow cytometry (FCM) assay demonstrated that MTX-loaded nanopartides were far superior to a pure drug in the inhibition of growth and proliferation of Hela cells. These results suggest that MTX mPEG CS NPs could be a promising targeting anticancer chemotherapeutic agent, especially for cervical carcinoma

Methotrexate-Loaded PEGylated Chitosan Nanoparticles: Synthesis, Characterization, and in Vitro and in Vivo Antitumoral Activity

key jointed Foundation of the National Science Foundation of China-Yunnan [U1137601]Cancer nanotherapeutics are rapidly progressing and being implemented to solve several limitations of conventional drug delivery systems. In this paper, we report a novel strategy of preparing methotrexate (MTX) nanopartides based on chitosan (CS) and methoxypoly(ethylene glycol) (mPEG) used as nanocarriers to enhance their targeting and prolong blood circulation. MTX and mPEG-conjugated CS nanopartides (NPs) were prepared and evaluated for their targeting efficiency and toxicity in vitro and in vivo. The MTX-mPEG-CS NP size determined by dynamic light scattering was 213 +/- 2.0 nm with a narrow particle size distribution, and its loading content (LC %) and encapsulation efficiency (EE) were 44.19 +/- 0.64% and 87.65 +/- 0.79%, respectively. In vitro release behavior of MTX was investigated. In vivo optical imaging in mice proved that MTX was released from particles subsequently and targeted to tumor tissue, showing significantly prolonged retention and specific selectivity. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay obviously indicated that the higher inhibition efficiency of MTX-mPEG-CS NPs meant that much more MTX was transferred into the tumor cells. A significant right-shift in the flow cytometry (FCM) assay demonstrated that MTX-loaded nanopartides were far superior to a pure drug in the inhibition of growth and proliferation of Hela cells. These results suggest that MTX mPEG CS NPs could be a promising targeting anticancer chemotherapeutic agent, especially for cervical carcinoma