Effect of Localized Mechanical Indentation on Skin Water Content Evaluated Using OCT

The highly disordered refractive index distribution in skin causes multiple scattering of incident light and limits optical imaging and therapeutic depth. We hypothesize that localized mechanical compression reduces scattering by expulsing unbound water from the dermal collagen matrix, increasing protein concentration and decreasing the number of index mismatch interfaces between tissue constituents. A swept-source optical coherence tomography (OCT) system was used to assess changes in thickness and group refractive index in ex vivo porcine skin, as well as changes in signal intensity profile when imaging in vivo human skin. Compression of ex vivo porcine skin resulted in an effective strain of −58.5%, an increase in refractive index from 1.39 to 1.50, and a decrease in water volume fraction from 0.66 to 0.20. In vivo OCT signal intensity increased by 1.5 dB at a depth of 1 mm, possibly due to transport of water away from the compressed regions. These finding suggest that local compression could be used to enhance light-based diagnostic and therapeutic techniques

GaSbBi alloys and heterostructures: fabrication and properties

International audienceDilute bismuth (Bi) III-V alloys have recently attracted great attention, due to their properties of band-gap reduction and spin-orbit splitting. The incorporation of Bi into antimonide based III-V semiconductors is very attractive for the development of new optoelectronic devices working in the mid-infrared range (2-5 µm). However, due to its large size, Bi does not readily incorporate into III-V alloys and the epitaxy of III-V dilute bismides is thus very challenging. This book chapter presents the most recent developments in the epitaxy and characterization of GaSbBi alloys and heterostructures

Optical properties of breast tumor phantoms containing carbon nanotubes and nanohorns

The degree by which optical properties of tumors are altered following introduction of carbon nanotubes (CNTs) of varying concentration and type is poorly understood, making it difficult to predict the impact of CNT inclusion on the photothermal response to laser therapies. Optical properties were measured of phantoms representative of breast tumor tissue incorporated with multiwalled carbon nanotubes (MWNTs), single-walled carbon nanotubes (SWNTs), and single-walled carbon nanohorns (SWNHs) of varying concentration (0.01–0.1 mg/ml). Tissue phantoms were made from sodium alginate (3 g/ml) incorporated with polystyrene microbeads (3 μm diam and 1 mg/ml) and talc-France powder (40 mg/ml). Absorption (μa) and reduced scattering (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}\mu^\prime _s\end{equation*} \end{document}μs′) coefficients of phantoms containing CNTs were determined by the inverse adding-doubling algorithm for the wavelength range of 400–1300 nm. Optical properties of phantoms without CNTs were in the range of μa = 1.04–0.06 mm−1 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}\mu^\prime _s\end{equation*} \end{document}μs′ = 0.05–0.07 mm−1 at a wavelength of 900 nm, which corresponds with published data for human breast tumor tissue. Incorporating MWNTs, SWNTs, and SWNHs in phantoms with a concentration of 0.1 mg/ml increased (μa) by 20- to 30-fold, 5- to 6-fold, and 9- to 14-fold, respectively, for the wavelength range of 800–1100 nm with minimal change in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}\mu^\prime _s\end{equation*} \end{document}μs′ (1.2- to 1.3-fold). Introduction of CNTs into tissue phantoms increased absorption, providing a means to enhance photothermal therapy

Species diversity and distribution pattern of avifauna from Thane creek, Maharashtra, India

Bird survey in Thane creek was conducted during winter season in 2015-2016. Total 69 species of birds were encountered belonging to 11 orders and 17 families in the entire creek. As per the IUCN Red list, of the 69 bird species, six near threatened and one vulnerable species were recorded. 60.87 percent birds were migratory winter visitors, 36.23 percent birds were residents and local migrants, and the remaining 2.89 percent birds were residents as well as winter visitors. Scolopacidae family had the highest representation with 14 bird species. Order Phoenicopteriformes had the highest number of individuals (N = 20539) with lesser flamingo contributing 80.22 percent. The Shannon-Weiner diversity indices revealed higher diversity upstream (2.56) followed by midstream (1.78) and downstream (1.12). Similarly, the evenness index showed the species were more evenly distributed upstream (0.219) followed by midstream (0.110) and downstream region (0.060). On the contrary, the dominance was higher downstream (0.501) followed by midstream (0.319) and upstream region (0.124). Order Phoenicopteriformes had the highest percent encounter rate with majority encountered in downstream followed by midstream region and sporadically distributed in the upstream region of the creek. The family with moderate to less number of individuals are majorly encountered in the upstream region of the creek. The birds showed a specific distribution pattern primarily because of food availability and also because of other biotic and abiotic factors