Numerical and experimental analysis on green laser crystallization of amorphous silicon thin films

The laser fluence effect on crystallization of amorphous silicon irradiated by a frequency-doubled Nd: YAG laser has been studied both theoretically and experimentally. An effective numerical model is set up to predict the melting threshold and the optimized laser fluence for crystallization of 200nm amorphous silicon. Temperature distribution with time and melt depth are analyzed. Besides the model, Raman spectra of thin films treated with different fluences are measured to confirm the phase transition and to determine the optimized fluence. The calculating results accord well with those obtained from the experimental data in this research

INFLUENCE OF LIGNOSULFONATES ON THE PROPERTIES OF DIMETHOMORPH WATER-DISPERSIBLE GRANULES

Different molecular weight fractions of lignosulfonates (LS), LS having different cations, and modified LS with different degree of sulfonation and intrinsic viscosity were prepared and used as dispersants for Dimethomorph water-dispersible granules (DWG). The suspending ratio of DWG was tested to evaluate the effectiveness of LS as a dispersant. Moreover, the stability of DWG suspensions was measured by a new instrument (Turbiscan LabExpert). The suspending ratios of DWG having different molecular weight fraction of LS increased with increasing molecular weight in a suitable range. The kind of cation associated with the LS didn’t have an obvious influence the effectiveness of LS as a dispersant. Furthermore, the higher degree of sulfonation of LS, of which the intrinsic viscosity was similar, the better was its effectiveness as a dispersant. When the intrinsic viscosity increased within a suitable range, the effectiveness of LS as a dispersant increased. Similar findings were achieved by evaluating the stability of DWG suspensions with all the LS as dispersants, and larger molecular weight could decrease the growth of particle size

Effect of Temperature on a Lignin-based Polymer with Two Types of Microstructures

A lignin-based polymer (GCL1-JB) was dispersed in solvents with different proportion between 1,4 dioxane and water for forming linear and spherical microstructures. The effects of temperature on the solution behaviors and adsorption characteristics of GCL1-JB with different microstructures were investigated by light scattering, conductivity, zeta potential, UV-Vis spectroscopy, atomic force microscopy (AFM), and contact angle measurements. Results showed that GCL1-JB solutions with different microstructures have different responses to environmental temperature changes, which is related to the movements of charges. For GCL1-JB with a spherical microstructure, as the temperature increases, the degree of ionization does not decrease. However, the surface charges decrease due to the charged groups moving from the surface into the interior because of the charge gradient, which induces a significant decrease in the zeta potential. As the surface charges decrease and the hydrophobic interaction increases, the GCL1-JB aggregates. Therefore, the scattered light intensity increases significantly and the corresponding GCL1-JB adsorbed film has a larger adsorbed amount, a more rough surface, and a larger contact angle. However, for GCL1-JB with a linear microstructure, the surface charges do not obviously change with a temperature increase, even though the charged groups move from side to side. Therefore, the zeta potential and the scattered light intensities of these GCL1-JB solutions are basically independent of temperature, and the corresponding adsorption characteristics do not obviously change

HBx inhibits CYP2E1 gene expression via downregulating HNF4α in human hepatoma cells.

CYP2E1, one of the cytochrome P450 mixed-function oxidases located predominantly in liver, plays a key role in metabolism of xenobiotics including ethanol and procarcinogens. Recently, down-expression of CYP2E1 was found in hepatocellular carcinoma (HCC) with the majority to be chronic hepatitis B virus (HBV) carriers. In this study, we tested a hypothesis that HBx may inhibit CYP2E1 gene expression via hepatocyte nuclear factor 4α (HNF4α). By enforced HBx gene expression in cultured HepG2 cells, we determined the effect of HBx on CYP2E1 mRNA and protein expression. With a bioinformatics analysis, we found a consensus HNF-4α binding sequence located on -318 to -294 bp upstream of human CYP2E1 promoter. Using reporter gene assay and site-directed mutagenesis, we have shown that mutation of this site dramatically decreased CYP2E1 promoter activity. By silencing endogenous HNF-4α, we have further validated knockdown of HNF-4α significantly decreased CYP2E1 expression. Ectopic overexpression of HBx in HepG2 cells inhibits HNF-4α expression, and HNF-4α levels were inversely correlated with viral proteins both in HBV-infected HepG2215 cells and as well as HBV positive HCC liver tissues. Moreover, the HBx-induced CYP2E1 reduction could be rescued by ectopic supplement of HNF4α protein expression. Furthermore, human hepatoma cells C34, which do not express CYP2E1, shows enhanced cell growth rate compared to E47, which constitutively expresses CYP2E1. In addition, the significantly altered liver proteins in CYP2E1 knockout mice were detected with proteomics analysis. Together, HBx inhibits human CYP2E1 gene expression via downregulating HNF4α which contributes to promotion of human hepatoma cell growth. The elucidation of a HBx-HNF4α-CYP2E1 pathway provides novel insight into the molecular mechanism underlining chronic HBV infection associated hepatocarcinogenesis

Platelet membrane camouflaged AIEgen‐mediated photodynamic therapy improves the effectiveness of anti‐PD‐L1 immunotherapy in large‐burden tumors

Abstract Although immunotherapy has achieved recent clinical success in antitumor therapy, it is less effective for solid tumors with large burdens. To overcome this challenge, herein, we report a new strategy based on platelet membrane‐camouflaged aggregation‐induced emission (AIE) luminogen (Plt‐M@P) combined with the anti‐programmed death ligand 1 (anti‐PD‐L1) for tumoral photodynamic‐immunotherapy. Plt‐M@P is prepared by using poly lactic‐co‐glycolic acid (PLGA)/PF3‐PPh3 complex as a nanocore, and then by co‐extrusion with platelet membranes. PF3‐PPh3 is an AIE‐active conjugated polyelectrolyte with photosensitizing capability for photodynamic therapy (PDT). Plt‐M@P exhibits superior tumor targeting capacity in vivo. When applied in small tumor‐bearing (~40 mm3) mice, Plt‐M@P‐mediated PDT significantly inhibits tumor growth. In tumor models with large burdens (~200 mm3), using Plt‐M@P‐mediated PDT or anti‐PD‐L1 alone is less effective, but the combination of both is effective in inhibiting tumor growth. Importantly, this combination therapy has good biocompatibility, as demonstrated by the absence of damage to the major organs, especially the reproductive system. In conclusion, we show that Plt‐M@P‐mediated PDT can improve anti‐PD‐L1 immunotherapy by enhancing antitumor effects, providing a promising strategy for the treatment of tumors with large burdens