A Fiber-Optic Fluorescence Microscope Using a Consumer-Grade Digital Camera for In Vivo Cellular Imaging

BACKGROUND: Early detection is an essential component of cancer management. Unfortunately, visual examination can often be unreliable, and many settings lack the financial capital and infrastructure to operate PET, CT, and MRI systems. Moreover, the infrastructure and expense associated with surgical biopsy and microscopy are a challenge to establishing cancer screening/early detection programs in low-resource settings. Improvements in performance and declining costs have led to the availability of optoelectronic components, which can be used to develop low-cost diagnostic imaging devices for use at the point-of-care. Here, we demonstrate a fiber-optic fluorescence microscope using a consumer-grade camera for in vivo cellular imaging. METHODS: The fiber-optic fluorescence microscope includes an LED light, an objective lens, a fiber-optic bundle, and a consumer-grade digital camera. The system was used to image an oral cancer cell line labeled with 0.01% proflavine. A human tissue specimen was imaged following surgical resection, enabling dysplastic and cancerous regions to be evaluated. The oral mucosa of a healthy human subject was imaged in vivo, following topical application of 0.01% proflavine. FINDINGS: The fiber-optic microscope resolved individual nuclei in all specimens and tissues imaged. This capability allowed qualitative and quantitative differences between normal and precancerous or cancerous tissues to be identified. The optical efficiency of the system permitted imaging of the human oral mucosa in real time. CONCLUSION: Our results indicate this device as a useful tool to assist in the identification of early neoplastic changes in epithelial tissues. This portable, inexpensive unit may be particularly appropriate for use at the point-of-care in low-resource settings

Synthesis, characterization and redox properties of novel vic-dioximes and their complexes with nickel(II), copper(II) and cobalt(II)

WOS: 000233365200005Two novel vie-dioxime, 1,2-dihydroxyimino-1-p-tolyl-3-aza-6-imidazole heptane (L1H2) and N-(ethyl-4-amino-1-piperidine carboxylate)-p-tolylglyoxime (L2H2) were prepared by the reaction of anti-p-tolylchloroglyoxime with 1-(3-aminopropyl)imidazole and ethyl-4-amino-1-piperidine carboxylate in absolute THE Mononuclear complexes with a metal-ligand ratio of 1:2 were prepared using Co(II), Cu(II) and Ni(II) salts. The ligands and their Co(II), Cu(II) and Ni(II) complexes were characterized by elemental analyses, FT-IR, UV-Vis, H-1-NMR and C-13-NMR and magnetic susceptibility measurements. The electrochemical behaviour of the complexes was investigated by cyclic voltammetry in dimethylsulfoxide. All metal complexes showed metal centered quasi reversible one-electron redox processes. However, metal complexes of the L2H2 ligand also exhibited ligand based irreversible redox waves

Voltammetric selectivity conferred by the modification of electrodes using conductive porous layers or films: The oxidation of dopamine on glassy carbon electrodes modified with multiwalled carbon nanotubes

Amperometric detection provides a highly sensitive approach to the electroanalytical determination of many target molecules and is widely used in the laboratory and field as well as in the form of disposable sensors. However, the approach can occasionally be restricted by limitations of selectivity; various species present in the target medium may oxidise or reduce at similar potentials. We show that the use of conducting porous layers on the surface of electrodes can be used to modify the mass transport regime from linear (planar) diffusion to one of approximately 'thin layer' character and that this alteration can in favourable circumstances facilitate the amperometric discrimination between species which oxidise or reduce at similar potentials under planar diffusion conditions. The method is illustrated with respect to the detection of dopamine at naked glassy carbon electrodes and at such electrodes modified with a layer of multiwalled carbon nanotubes, and experiments are reported which are consistent with the proposed strategy. The literature for the electroanalytical amperometric detection of dopamine in the presence of interfering molecules such as uric acid, serotonin and ascorbic acid, which often are found to oxidise at potentials close to dopamine, is reviewed and the modus operandi for many chemically modified electrodes apparently designed for the sought resolution of dopamine from these species are found to possibly rely on the physical mechanism proposed. © 2009 Elsevier B.V. All rights reserved

Do sunspot numbers cause global temperatures? Evidence from a frequency domain causality test

This article applies the causality test in the frequency domain, developed by Breitung and Candelon (2006), to analyse whether sunspot numbers (used as a partial approximation to solar irradiance) cause global temperatures, using monthly data covering the time period 1880:1–2013:9. While standard time domain Granger causality test fails to reject the null hypothesis that sunspot numbers do not cause global temperatures for both full and sub-samples (identified based on tests of structural breaks), the frequency domain causality test detects predictability for both the full-sample and the last sub-sample at short (2–2.6 months) and long (10.3 months and above) cycle lengths, respectively. Our results highlight the importance of analysing causality using the frequency domain test, which, unlike the time domain Granger causality test, allows us to decompose causality by different time horizons, and hence, could detect predictability at certain cycle lengths even when the time domain causality test might fail to pick up any causality. Further, given the widespread discussion in the literature, those results for the full-sample causality, irrespective of whether it is in time or frequency domains, cannot be relied upon when there are structural breaks present, and one needs to draw inference regarding causality from the sub-samples, we can conclude that there has been an emergence of causality running from sunspot numbers to global temperatures only recently at cycle length of 10.3 months and above.http://www.tandfonline.com/loi/raec202016-05-30hb201