Low-temperature direct dehydrogenation of propane over binary oxide catalysts: insights into geometric effects and active sites

Binary ZnZrxOy catalysts were prepared and employed to catalyze propane dehydrogenation at relatively low temperatures. The evaluation of these materials for propane dehydrogenation was supplemented by material characterization and density functional theory calculations, to provide molecular insights into the nature of the catalytic active sites. Combined, these experiments suggested that coordinatively unsaturated Zn cations (Zncus) in Zncus–O–Zrcus were the active sites for the first step of propane dehydrogenation, and coordinatively unsaturated Zr cations (Zrcus) in Zncus–O–Zrcus were active sites for the second step. This synergistic effect, derived from both these components, led to significant enhancements in activity. Furthermore, the combination of Zn and Zr species resulted in notable changes to the structure of the catalysts, leading to both the formation of the Zrcus active site and improved oxygen mobility. ZnZr2 exhibited relatively high activity

Controlled manipulation of TRAIL into single human colon cancer cells using atomic force microscope

In this study, an AFM tip was used to penetrate the human colon cancer cells (SW480) in the culture medium containing pEGFP-N1-TRAIL plasmids. The trail plasmids encoded with the enhanced green fluorescent protein (EGFP) were moved into the SW480 cells through membrane holes created by the AFM probe. Following the penetration, the culture medium was changed into the RPMI1640 medium supplemented with 10% of fetal bovine serum and incubated for 24h. The expression of PEGFP-N1-TRAIL in SW480 cells was then observed by inverted fluorescence microscope. The experiment results indicate that the AFM tip can be used to penetrate the membranes of targeted cells individually

AFM-detected apoptosis of hepatocellular carcinoma cells induced by American ginseng root water extract

American ginseng as a common and traditional herbal medicine has been used in cancer treatment for many years. However, the effect of American ginseng on the cancer cell response (i.e. apoptosis) has not been fully understood yet. Previous studies demonstrated that cellular apoptosis was associated with the changes of mechanical and morphological properties. Therefore, in this study, mechanical and morphological characterizations were carried out by both atomic force microscope (AFM) and inverted optical microscope to investigate the apoptosis of hepatocellular carcinoma (SMMC-7721) cells affected by American ginseng root water extract (AGRWE). The results showed that the cells treated with AGRWE exhibited significantly larger surface roughness, height and elastic modulus values than control group. Moreover, those parameters were upregulated under the higher concentration of AGRWE and longer culture time. Consequently, it indicates that the mechanical and morphological properties can be used as the apoptotic characteristics of SMMC-7721 cells. Also, the increased surface roughness and elastic modulus of cells under the AGRWE treatment have shown that the apoptosis of SMMC-7721 cells can be enhanced by AGRWE. This will provide an important implication for hepatocelluar carcinoma treatment and drug development

Compensation of the magnetic force imaging by scanning directions

It was found that the results of magnetic force microscope (MFM) imaging were different with the probe scanning directions. This paper studied the effect of scanning directions on the MFM imaging, and a method for the distortion compensation was proposed to reduce the errors. In the study, three different scanning directions with the angles of 0°, 45° and 90° were used to measure the magnetic domain structures distributions of magnetic sample. The experimental results have shown that the scanning direction parallel to the magnetic domain structure will cause a minimum phase shift difference and lead to a structure distortion. A method for compensating the distortions was proposed. With this method, the distorted structures were corrected and the effect of scanning directions on the MFM imaging was significantly reduced. This work provides a way for the acquisition of the correct images of magnetic structures using an MFM and the improvement of imaging quality in a wide range of MFM applications

Cardiomyocyte contractile force changes in response to AGRWE detected by AFM

The cardiac contractile force is an important predictor of healthy and cardiovascular diseases. The changes of cardiomyocyte contractile force in response to American ginseng root water extract (AGRWE) detected by atomic force microscope have not been investigated yet. This study examined the effects of AGRWE on single beating cardiomyocytes extracted from a newborn rat. The same cardiomyocytes were incubated with AGRWE at a concentration of 50 μg/ml for about 30 min, and the cardiomyocytes' contractile force increased from 1.74 ± 1.01 to 3.49 ± 1.53 nN. The mean value of the contractile strain calculated was 3.32 ± 1.55% for the cardiomyocyte before the treatment with AGRWE, while for the cardiomyocyte treated with AGRWE it increased to 4.60 ± 1.35%. The results also showed that the beating rate of the same single beating cardiomyocytes was decreased from 34 ± 11 beats/min (control, n = 10) to 20 ± 9 beats/min. In conclusion, the experimental results have shown clearly that the contractile forces and strain of single beating cardiomyocytes treated with AGRWE are significantly higher than the control group, while the heart rate was decreased. It suggests that ginseng agents are promising candidates in improving cardiac functions for treating heart failure

Response of MG63 osteoblast cells to surface modification of Ti-6Al-4V implant alloy by laser interference lithography

The response of human osteoblast-like osteosarcoma cells (MG63) to surface modification of Ti-6Al-4V implant alloy was investigated by Laser Interference Lithography (LIL). In this work, laser interference lithography was employed to fabricate the microstructures of grooves, dots and dimples onto the surfaces of Ti-6Al-4V samples. Two and three beam LIL systems were developed to carry out the experiments. The laser treatment resulted in the increases of the roughness and the contact angle of water on the implant alloy surfaces. The proliferation of osteoblasts was analyzed by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay for the time periods of 4 hours, 2 days, 3 days, and 6 days. The MTT test results demonstrated that the laser treatment surfaces had a positive impact on the proliferation of osteoblast cells after 24 hours. The alloy surface morphology and the morphological changes of MG63 cells cultured on the laser textured Ti-6Al-4V surface were observed by Scanning Electron Microscope (SEM). The SEM results indicated that the osteoblast cells were aligned on grooved surfaces and they were prolonged with the structures. Enzymatic detachment results showed that the 20 µm grooved structures provided the better cell adhesion to the textured Ti-6Al-4V surfaces