836 research outputs found
Procurement specification color graphic camera system
The performance and design requirements for a Color Graphic Camera System are presented. The system is a functional part of the Earth Observation Department Laboratory System (EODLS) and will be interfaced with Image Analysis Stations. It will convert the output of a raster scan computer color terminal into permanent, high resolution photographic prints and transparencies. Images usually displayed will be remotely sensed LANDSAT imager scenes
Feasibility of multiphoton microscopy-based quantification of antibiotic uptake into neutrophil granulocytes
Antibiotic levels in livestock are usually evaluated through destructive analysis. Taking advantage of the fluorescent properties of marbofloxacin (MBX) and trovafloxacin (TVX), multiphoton microscopy (MPM) was evaluated as a minimally invasive and nondestructive method to determine the penetration of TVX and MBX into sheep neutrophils. Standard curves were measured with drug-only solutions and suggested that MBX was more suited for this type of analysis. The intracellular concentration of both TVX and MBX was higher than the extracellular concentration after incubating neutrophils for 30 min at concentrations ranging from 0.1 to 100 mu g/ml for both the drugs. The intracellular concentration of TVX increased with the extracellular concentration but was always greater than the extracellular concentration, suggesting active internalization. On the other hand, intracellular/extracellular ratio (I/E) peaked at 1.6-fold I/E for 1 mu g/ml and then gradually decreased with increased concentration to 1.2-fold I/E at 100 mu g/ml. For the first time, this study showed the use of MPM to quantify antibiotic uptake by sheep neutrophils and observed that both antibiotics were taken up by sheep neutrophils beyond extracellular levels. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI
Nanodispersed UV blockers in skin-friendly silica vesicles with superior UV-attenuating efficiency
Using a pig ear skin model, it is demonstrated that silica vesicles show higher skin safety compared to dense silica nanoparticles with similar sizes. A hydrophobic UV blocker is efficiently dispersed in silica vesicles in an amorphous state, leading to ultrahigh UV-attenuating efficiency and a sun protection factor of 100 in a sunscreen formulation
Nanoparticle tethered antioxidant response element as a biosensor for oxygen induced toxicity in retinal endothelial cells
Purpose: A novel system, based on biosensor DNA tethered to a nanoparticle, was developed for the treatment of retinopathy of prematurity. Methods: The construction of a five-layered nanoparticle was visualized with gel electrophoresis. Transcriptionally active PCR products (TAP) containing the biosensor sequence, were bioconjugated to the surface of magnetic nanoparticles yielding biosensor tethered magnetic nanoparticles (MNP). The biosensor was based on an enhanced green fluorescent protein (EGFP) reporter gene driven by an enhanced antioxidant response element ( ARE). Image analysis and flow cytometry were used to characterize MNP delivery and biosensor activity. Results: The MNP penetrated dividing and migrating cells more often than quiescent endothelial cells in a wound-healing in vitro assay. Prussian blue staining demonstrated that more cells have nanoparticle cores than are transfected. When compared to naked TAP alone, MNP transfected more cells in a dose dependent manner. Both the biosensor alone and MNP induce gene expression in the presence of hyperoxia, greater than 1.5 fold over normoxic controls. These data also show that the MNP had a signal to noise ratio of 0.5 greater than the plasmid form of the biosensor as demonstrated by flow cytometry. Conclusions: This approach has the potential to allow the endothelial cells of the retinal vasculature to prevent or treat themselves after hyperoxic insult, rather than systemic treatment to protect or treat only the retina
Feasibility study for a numerical aerodynamic simulation facility. Volume 1
A Numerical Aerodynamic Simulation Facility (NASF) was designed for the simulation of fluid flow around three-dimensional bodies, both in wind tunnel environments and in free space. The application of numerical simulation to this field of endeavor promised to yield economies in aerodynamic and aircraft body designs. A model for a NASF/FMP (Flow Model Processor) ensemble using a possible approach to meeting NASF goals is presented. The computer hardware and software are presented, along with the entire design and performance analysis and evaluation
The importance of high-throughput cell separation technologies for genomics/proteomics-based clinical diagnostics
Gene expression microarray analyses of mixtures of cells approximate a weighted average of the gene expression profiles (GEPs) of each cell type according to its relative abundance in the overall cell sample being analyzed. If the targeted subpopulation of cells is in the minority, or the expected perturbations are marginal, then such changes will be masked by the GEP of the normal/unaffected cells. We show that the GEP of a minor cell subpopulation is often lost when that cell subpopulation is of a frequency less than 30 percent. The GEP is almost always masked by the other cell subpopulations when that frequency drops to 10 percent or less. On the basis of these results one should always assume that the GEP of a given cell subpopulation is probably seriously affected by, the presence of significant numbers of other "contaminating" cell types. Several methodologies can be employed to enrich the target cells submitted for microarray analyses. These include magnetic sorting and laser capture microdissection. If a cell subpopulation of interest is small, very high-throughput cell separation technologies are needed to separate enough cells for conventional microarrays. However, high-throughput flow cytometry/cell sorting overcomes many restrictions of experimental enrichment conditions. This technology can also be used to sort smaller numbers of cells of specific cell subpopulations and subsequently amplify their mRNAs before microarray analyses. When purification techniques are applied to unfixed samples, the potential for changes in gene levels during the process of collection is an additional concern. Since RNA rapidly degrades, and specific mRNAs turn over in minutes or hours, the cell separation process must be very rapid. Hence, high-throughput cell separation (HTS) technologies are needed that can process the necessary number of cells expeditiously in order to avoid such uncontrolled changes in the target cells GEP. In cases where even the use of HTS yields only a small number of cells, the mRNAs (after reverse transcription to cDNA's) must be amplified to yield enough material for conventional microarray analyses. However, the problem of using "microamplification" PCR methods to expand the amount of cDNAs (from mRNAs) is that it is very difficult to amplify equally all of the mRNAs. Unequal amplification leads to a distorted gene expression profile on the microarray. Linear amplifications is difficult to achieve. Unfortunately, present-day gene-chips need to be about 100 times more sensitive than they are now to be able to do many biologically and biomedically meaningful experiments and clinical tests
Diffuse reflectance imaging for non-melanoma skin cancer detection using laser feedback interferometry
We propose a compact, self-aligned, low-cost, and versatile infrared diffuse-reflectance laser imaging system using a laser feedback interferometry technique with possible applications in in vivo biological tissue imaging and skin cancer detection. We examine the proposed technique experimentally using a three-layer agar skin phantom. A cylindrical region with a scattering rate lower than that of the surrounding normal tissue was used as a model for a non-melanoma skin tumour. The same structure was implemented in a Monte Carlo computational model. The experimental results agree well with the Monte Carlo simulations validating the theoretical basis of the technique. Results prove the applicability of the proposed technique for biological tissue imaging, with the capability of depth sectioning and a penetration depth of well over 1.2 mm into the skin phantom
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