333 research outputs found
Label-Free Nanometer-Resolution Imaging of Biological Architectures through Surface Enhanced Raman Scattering
Label free imaging of the chemical environment of biological specimens would readily bridge the supramolecular and the cellular scales, if a chemical fingerprint technique such as Raman scattering can be coupled with super resolution imaging. We demonst
Separation of Alcohol-Ester Binary Mixtures by Pervaporation
In this study, the pervaporation behavior of azeotrope forming methanol-methyl acetate and ethanol-ethyl acetate binary mixtures at different compositions was investigated at 30 and 45 °C using PE-based films having different thickness, compositions and structures, and a PET film. Experimental fluxes and selectivities of the permeating components were determined and evaluated on the basis of the feed mixtures and membranes. In addition, sorption measurements were taken for pure permeating components to observe the interactions between the polymeric membrane and the feed component
Composite Films of Arabinoxylan and Fibrous Sepiolite: Morphological, Mechanical, and Barrier Properties
Hemicelluloses represent a largely unutilized resource for future bioderived films in packaging and other applications. However, improvement of film properties is needed in order to transfer this potential into reality. In this context, sepiolite, a fibrous clay, was investigated as an additive to enhance the properties of rye flour arabinoxylan. Composite films cast from arabinoxylan solutions and sepiolite suspensions in water were transparent or semitransparent at additive loadings in the 2.5-10 wt % range. Scanning electron microscopy showed that the sepiolite was well dispersed in the arabinoxylan films and sepiolite fiber aggregation was not found. FT-IR spectroscopy provided some evidence for hydrogen bonding between sepiolite and arabinoxylan. Consistent with these findings, mechanical testing showed increases in film stiffness and strength with sepiolite addition and the effect of poly(ethylene glycol) methyl ether (mPEG) plasticizer addition. Incorporation of sepiolite did not significantly influence the thermal degradation or the gas barrier properties of arabinoxylan films, which is likely a consequence of sepiolite fiber morphology. In summary, sepiolite was shown to have potential as an additive to obtain stronger hemicellulose films although other approaches, possibly in combination with the use of sepiolite, would be needed if enhanced film barrier properties are required for specific applications.</p
A model with electric fields for the inclusion of mutual coupling effects in the MIMO channel
[No abstract available
Investigation of planar and conformal printed arrays for MIMO performance analysis
MIMO channel capacity of printed arrays with dipole elements is analyzed. A MIMO channel model based on electric fields is used. The effects of mutual interactions among the array elements through space and surface waves are included into the channel matrix using a full-wave hybrid Method of Moments (MoM)/Green's function technique in the spatial domain. MIMO capacity of printed arrays is then compared with that of free standing thin wire dipole arrays. Results show better performance of printed arrays
Description of an activity-based enzyme biosensor for lung cancer detection
BACKGROUND: Lung cancer is associated with the greatest cancer mortality as it typically presents with incurable distributed disease. Biomarkers relevant to risk assessment for the detection of lung cancer continue to be a challenge because they are often not detectable during the asymptomatic curable stage of the disease. A solution to population-scale testing for lung cancer will require a combination of performance, scalability, cost-effectiveness, and simplicity.METHODS: One solution is to measure the activity of serum available enzymes that contribute to the transformation process rather than counting biomarkers. Protease enzymes modify the environment during tumor growth and present an attractive target for detection. An activity based sensor platform sensitive to active protease enzymes is presented. A panel of 18 sensors was used to measure 750 sera samples from participants at increased risk for lung cancer with or without the disease.RESULTS: A machine learning approach is applied to generate algorithms that detect 90% of cancer patients overall with a specificity of 82% including 90% sensitivity in Stage I when disease intervention is most effective and detection more challenging.CONCLUSION: This approach is promising as a scalable, clinically useful platform to help detect patients who have lung cancer using a simple blood sample. The performance and cost profile is being pursued in studies as a platform for population wide screening.</p
Interval oscillation criteria for second-order nonlinear forced differential equations involving variable exponent
Electronic Structure and Bonding of Icosahedral Core-Shell Gold-Silver Nanoalloy Clusters Au_(144-x)Ag_x(SR)_60
Atomically precise thiolate-stabilized gold nanoclusters are currently of
interest for many cross-disciplinary applications in chemistry, physics and
molecular biology. Very recently, synthesis and electronic properties of
"nanoalloy" clusters Au_(144-x)Ag_x(SR)_60 were reported. Here, density
functional theory is used for electronic structure and bonding in
Au_(144-x)Ag_x(SR)_60 based on a structural model of the icosahedral
Au_144(SR)_60 that features a 114-atom metal core with 60 symmetry-equivalent
surface sites, and a protecting layer of 30 RSAuSR units. In the optimal
configuration the 60 surface sites of the core are occupied by silver in
Au_84Ag_60(SR)_60. Silver enhances the electron shell structure around the
Fermi level in the metal core, which predicts a structured absorption spectrum
around the onset (about 0.8 eV) of electronic metal-to-metal transitions. The
calculations also imply element-dependent absorption edges for Au(5d)
\rightarrow Au(6sp) and Ag(4d) \rightarrow Ag(5sp) interband transitions in the
"plasmonic" region, with their relative intensities controlled by the Ag/Au
mixing ratio.Comment: 4 figure
Integrative DNA Methylation and Gene Expression Analyses Identify DNA Packaging and Epigenetic Regulatory Genes Associated with Low Motility Sperm
In previous studies using candidate gene approaches, low sperm count (oligospermia) has been associated with altered sperm mRNA content and DNA methylation in both imprinted and non-imprinted genes. We performed a genome-wide analysis of sperm DNA methylation and mRNA content to test for associations with sperm function. (NCBI 1788). There was a trend among altered expression of these epigenetic regulatory genes and RPMM DNA methylation class.Using integrative genome-wide approaches we identified CpG methylation profiles and mRNA alterations associated with low sperm motility
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