Purpose-(1) To demonstrate the capability of ultra high resolution anterior segment optical coherence tomography (UHR-OCT) to image Descemet's membrane (DM) and measure its thickness in vivo. (2) To evaluate the use of DM characteristics and thickness in the diagnosis of Fuchs' dystrophy.
Design-Case-Control StudyParticipants-20 eyes of 12 Fuchs' dystrophy patients, 20 eyes of 13 young normal and 20 eyes of 15 elderly normal subjects.Methods-Subjects were imaged using novel custom-built UHR-OCT. Images were used to describe the characteristics of DM. Custom-made software was used to measure DM thickness and central corneal thickness (CCT). Specimens of DM obtained from Fuchs' dystrophy patients who underwent endothelial keratoplasty (EK) were histopathologically examined. Regression analyses were used to assess the correlation of DM thickness measured by UHR-OCT in vivo and by light microscopy and to determine the intergroup correlations between age, CCT and DM thickness.
Main Outcome Measures-DM characteristics and thickness, CCT and age.Results-Using UHR-OCT, DM appeared in normal young subjects as a single opaque smooth line and in normal elderly subjects as a band of two smooth opaque lines with a translucent space in between. In Fuchs' dystrophy, DM appeared as a thickened band of two opaque lines; the anterior line was smooth while the posterior line had a wavy and irregular appearance with areas of localized thickenings. DM thickness measured in vivo by UHR-OCT correlated significantly to that measured by light microscopy in five Fuchs' dystrophy eyes that underwent EK. The average central thicknesses of DM in normal young, in normal elderly and in Fuchs' dystrophy eyes were 10 ± 3 μm, 16 ± 2 μm, and 34 ± 11 μm respectively (P < 0.001). There was a significant correlation between age and DM thickness only in normal groups. In Fuchs' dystrophy patients, there was a significant correlation between CCT and DM thickness which was non-significant for normal groups.
In the present study, octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA-POSS) functionalized carbon dots (CDs/POSS) are prepared by a one-pot approach with glycerol as carbon source and solvent medium. OA-POSS serves as a passivation agent, and it is obtained via hydrolytic condensation of 3-aminopropyltriethoxysilane (APTES). During the functionalization process, the amino groups on OA-POSS combine with carboxylic groups on the bare CDs via formation of amide bond to construct organic-inorganic hybrid carbon dots. The obtained CDs/POSS are well dispersed in aqueous medium with a diameter of ca. 3.6 nm. It is demonstrated that CDs/POSS provide favorable photoluminescent property with a quantum yield of 24.0%. They also exhibit resistance to photobleaching and excellent photoluminescence stability in the presence of biological sample matrix (characterized by heavy metals and organic molecules), which facilitate cell imaging in biological systems. Both the photoluminescent emission wavelength and the fluorescence intensity depend closely on the excitation wavelength, and thus, it provides a potential for multicolor imaging as demonstrated with HeLa cells and MCF-7 cells.
Numerical weather prediction (NWP) models are gaining more and more attention in providing high-resolution rainfall forecasts for real-time flood forecasting. In this study, the weather research and forecasting (WRF) model is integrated with the probability distribution model (PDM) to make real-time flow forecasts in a small catchment located in Southwest England. In order to improve the accuracy of the NWP rainfall and flow forecasts, dual real-time updating is carried out in the forecasting system through data assimilation. The three-dimensional variational data assimilation technique is coupled with the WRF model to assimilate radar reflectivity and traditional meteorological data; meanwhile, the autoregressive moving average model works with the rainfall-runoff model PDM to assimilate real-time flow observations. Four 24-h storm events with different characteristics of rainfall-runoff responses are selected from the study catchment to test the performance of the constructed forecasting system. The flood forecasting accuracy is found to be largely improved by incorporating the NWP forecasted rainfall when the lead time is beyond the catchment concentration time. The assimilation of radar and meteorological data also shows great advantage in improving the NWP rainfall forecasts.
A highly
sensitive platform is developed for the determination
of microRNA-21 (miRNA-21) with inductively coupled plasma mass spectrometry
(ICPMS). It includes the following operations: Hairpin structures
DNA H1 and H2 are designed, and DNA H1 is bound to ultrasmall lanthanide
upconversion nanoparticles (UCNPs) to produce UCNPs@DNA conjugate
probes. Target miRNA triggers a chain reaction for alternating hybridization
between DNA H1 (bound on UCNPs@DNA probe) and DNA H2. This leads to
UCNPs accumulation and serves as an efficient amplification strategy
for UCNPs. The concentration of miRNA-21 is closely correlated to
the number of UCNPs; thus, the detection of 89Y by ICPMS
provides a promising approach for miRNA quantification. This protocol
exhibits high sensitivity to miRNA-21 within 0.1–500 fM, along
with a detection limit of 41 aM, which is among the hitherto reported
most sensitive procedures. It is worth mentioning that rare earth
elements are scarcely present in living systems, which minimizes the
background for ICPMS detection and excludes potential interferences
from the coexisting species, which is most suited for biological assay.
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