Single metal nanoparticles and nanoaggregates are known to emit intense bursts of surface-enhanced Raman scattering (SERS) in an intermittent on and off fashion. The characteristic "blinking" timescales range from milliseconds to seconds. Here we report detailed temperature dependence (both heating and cooling) and light-intensity studies to further examine the origins of this intriguing phenomenon. The results indicate that blinking SERS contains both a thermo-activated component and a light-induced component. Several lines of evidence suggest that the observed fluctuations are caused by thermally activated diffusion of individual molecules on the particle surface, coupled with photo-induced electron transfer and structural relaxation of surface active sites or atomic-scale roughness features.
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http://dx.doi.org/10.1039/b509223j | DOI Listing |
PLoS One
October 2024
Department of Anthropology, University of Connecticut, Storrs, CT, United States of America.
Tracing the phylogenetic relationships between species is one of the fundamental objectives of evolutionary biology. Since Charles Darwin's seminal work in the 19th century, considerable progress has been made towards establishing a tree of life that summarises the evolutionary history of species. Nevertheless, substantial uncertainties still remain.
View Article and Find Full Text PDFJ Histochem Cytochem
February 2024
Division of Bio-Prosthodontics, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
The cementum is a highly mineralized tissue that covers the tooth root. The regional differences among the types of cementum, especially in the extrinsic fibers that contribute to tooth support, remain controversial. Therefore, this study used second harmonic generation imaging in conjunction with automated collagen extraction and image analysis algorithms to facilitate the quantitative examination of the fiber characteristics and the changes occurring in these fibers over time.
View Article and Find Full Text PDFCommunalizing colonial policies (CCPs) include a variety of practices that recognize and institutionalize communal difference among colonized populations, and several qualitative analyses find that they promoted postcolonial ethnic conflict. In contrast, the few quantitative analyses that explore this issue focus on several mechanisms, make conflicting claims, and provide mixed results, thereby suggesting that CCPs do not have general effects. Yet the quantitative findings might be inaccurate for several reasons: Some use the identity of the colonizer as a proxy for CCPs, others measure a CCP but have small samples with limited variation in the focal independent variable, and all of these analyses are unable to explore whether CCPs affect ethnic conflict through different and competing mechanisms.
View Article and Find Full Text PDFAnat Rec (Hoboken)
April 2022
Basic Sciences Department, College of Osteopathic Medicine, Touro University California, Vallejo, California, USA.
Since its establishment as one of the major authorities on the human body, Anatomy has played a crucial role in social and political spheres. In this article, I review how the history of Anatomy has intersected with queer history and how the effects of these interactions have affected queer lives today. In these historical cases, I aim to demonstrate how Anatomy has affected the social organization of human culture and society and also how society has affected anatomical knowledge in return.
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