PubMed · 6579639
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
J M Snyder. 1983. Gold.. https://pubmed.ncbi.nlm.nih.gov/6579639/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Sustainable nanomaterial synthesis has emerged as a critical strategy to reduce the environmental burden associated with conventional chemical synthesis method. Microalgae-derived biomolecules offer a promising platform for the green production of metal nanoparticles due to their rich bioactive compounds capable of acting as natural reducing and stabilizing agents. Here, we report the eco-friendly synthesis of gold nanoparticles (AuNPs) using extract of Indonesian microalga Chlorella vulgaris extract. To optimize the synthesis process, the effects of precursor-to-extract ratio, temperature, and incubation time were evaluated. Optimal synthesis of C5-AuNPs was obtained at 37 °C for 20 h with precursor to extract ratio of 6:4, resulting in moderately stable C5-AuNPs characterized by a surface plasmon resonance (SPR) peak at 541 nm. Furthermore, Fourier-transmission infra-red (FT-IR) analysis revealed the involvement of functional groups of C. vulgaris extract in the interaction with Au+ during the production of C5-AuNPs. Transmission electron microscopy (TEM) demonstrated the formation of uniformly spherical nanoparticles with an average diameter of approximately 8.8 nm. Biological evaluation showed that the synthesized C5-AuNPs exerted pronounced dose-dependent cytotoxicity against MCF-7 breast cancer cells with an IC50 threshold of 21.17 ppm, while no toxicity appears in normal HEK293 cells. Mechanistically, the C5-AuNPs induced early apoptosis and inhibit cell-cycle progression at the stage of G0/G1. Collectively, these findings demonstrate that C. vulgaris-mediated AuNPs represent a promising preliminary in vitro findings for cancer therapy candidate.
Atomic steps on (111) and (100) crystal surfaces of Pt were observed using a commercial scanning electron microscope (SEM) in secondary electron mode. By comparing the SEM images and those by reflection electron microscopy (REM), the observed contrast was confirmed to be that from atomic steps on crystal surfaces. The contrast mechanism is briefly discussed. One application of this imaging technique is also shown.
Two beam interferences produced using an electrostatic biprism, which is inserted in the position of the selected area diaphragm of a commercial electron microscope, may be used in reflection electron microscopy to determine the phase shifts induced by structures on single crystal surfaces. A description of our interferometrical and holographical experiments on the phase shift at steps on (111)Au and (111)Pt single crystal surfaces is given and a straight forward interpretation of the results in terms of refraction will be discussed. As a particular result phase shifts of pi and 0.9 pi were measured for monatomic steps on (111)gold and (111)platinum surfaces, respectively.