We present the uniform and high-yield synthesis of a novel gold nanostructure of compass shape composed of a Au sphere at the central and two gradually thinning conical tips at the opposed poles. The Au compass shapes were synthesized through a seed-mediated growth approach employing a binary mixture of cetyltrimethylammonium bromide (CTAB) and sodium oleate (NaOL) as the structure-directing agents. Under the condition of single surfactant (CTAB), the spherical seeds tend to grow into larger spherical Au nanoparticles (NPs); while the spherical seeds favor the formation of Au compass shaped NPs using two mixed surfactants (CTAB/NaOL). The reaction kinetics clearly shows a growth mechanism of Au compass shaped NPs. Interestingly, due to their anisotropic structure, Au compass shaped NPs show two distinctive plasmonic resonances, similar to those from Au nanorods. Particularly, the longitudinal surface plasmon resonances of Au compass shaped NPs exhibit a broadly tunable range from 600 to 865 nm. In addition, the obtained Au compass shaped NPs can be self-assembled into a two-dimensional monolayer with closely packed and highly aligned NPs, which results in periodic arrays of overlapped Au tips, generating hot spots for high-performance surface-enhanced Raman scattering.
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http://dx.doi.org/10.1021/acsami.6b05258 | DOI Listing |
J Cancer Policy
December 2024
Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA.
Biosimilars and generics have led to reduced cancer drug prices. The effect of biosimilar or generic drug competition on drug manufacturer revenue has not been previously described. In this study, the majority of top selling cancer drugs had a greater than 50 % decline in sales revenue within 2 years of generic or biosimilar market entry, reflecting both the decline in market share and reduction in unit drug price.
View Article and Find Full Text PDFProc Biol Sci
November 2024
School of Environmental and Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK.
Migratory birds are able to navigate over great distances with remarkable accuracy. The mechanism they use to achieve this feat is thought to involve two distinct steps: locating their position (the 'map') and heading towards the direction determined (the 'compass'). For decades, this map-and-compass concept has shaped our perception of navigation in animals, although the nature of the map remains debated.
View Article and Find Full Text PDFBMC Palliat Care
November 2024
Nursing Research Center, Golestan University of Medical Sciences, Gorgan, Iran.
Background: Providing high-quality end-of-life care is currently a paramount health priority. Given that the standard of care is intrinsically linked to nurses' motivations, it is becoming too imperative to explore the contributing factors Consequently, this study was undertaken to elucidate the experiences of Iranian nurses regarding their motivation for delivering end-of-life care.
Methods: This research is a qualitative, descriptive inquiry employing conventional content analysis, carried out at two governmental hospitals in Gorgan, northern Iran, from February to July 2023.
J Neurointerv Surg
November 2024
Neurosurgery, Gates Vascular Institute, Buffalo, New York, USA
J Exp Biol
October 2024
Graduate Neuroscience Program, University of California, Riverside, Riverside, CA 92521, USA.
Celestial orientation and navigation are performed by many organisms in contexts as diverse as migration, nest finding and straight-line orientation. The vinegar fly, Drosophila melanogaster, performs menotaxis in response to celestial cues during tethered flight and can disperse more than 10 km under field conditions. However, we still do not understand how spectral components of celestial cues and pauses in flight impact heading direction in flies.
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