471 research outputs found
Band-edge Bilayer Plasmonic Nanostructure for Surface Enhanced Raman Spectroscopy
Spectroscopic analysis of large biomolecules is critical in a number of
applications, including medical diagnostics and label-free biosensing.
Recently, it has been shown that Raman spectroscopy of proteins can be used to
diagnose some diseases, including a few types of cancer. These experiments have
however been performed using traditional Raman spectroscopy and the development
of the Surface enhanced Raman spectroscopy (SERS) assays suitable for large
biomolecules could lead to a substantial decrease in the amount of specimen
necessary for these experiments. We present a new method to achieve high local
field enhancement in surface enhanced Raman spectroscopy through the
simultaneous adjustment of the lattice plasmons and localized surface plasmon
polaritons, in a periodic bilayer nanoantenna array resulting in a high
enhancement factor over the sensing area, with relatively high uniformity. The
proposed plasmonic nanostructure is comprised of two interacting nanoantenna
layers, providing a sharp band-edge lattice plasmon mode and a wide-band
localized surface plasmon for the separate enhancement of the pump and emitted
Raman signals. We demonstrate the application of the proposed nanostructure for
the spectral analysis of large biomolecules by binding a protein (streptavidin)
selectively on the hot-spots between the two stacked layers, using a low
concentration solution (100 nM) and we successfully acquire its SERS spectrum
New Modified Method of the Chebyshev Collocation Method for Solving Fractional Diffusion Equation
In this article a modification of the Chebyshev collocation method is applied to the solution of space fractional differential equations. The fractional derivative is considered in the Caputo sense. The finite difference scheme and Chebyshev collocation method are used. The numerical results obtained by this approach have been compared with other methods. The results show the reliability and efficiency of the proposed method
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Some two-dimensional biharmonic formulations
This thesis develops biharmonic analysis building upon the fundamental contributions which have been made by Almansi and Hadamard nearly one hundred years ago. The representations of Massonnet and Chakrabarty are discussed. It also makes a new analysis of the two-dimensional Papkovich-Neuber formula for elastostatic displacement fields, which is compared with Muskhelishvili's displacement formula for such fields
High Throughput Ion-Implantation for Silicon Solar Cells
AbstractIon implantation is a technique that has been demonstrated to improve solar cell efficiency and eliminate process steps in standard and advanced cell designs. Intevac has developed a high productivity, continuous flux ion implantation tool for solar cells. We demonstrate improved n-type emitters over POCl3 diffused emitters, and selective patterning capabilities. Additionally, it is shown that non-mass analyzed implantation provides similar performance as mass-analyzed implantation, yet at a much lower capital cost
Immittance Matching for Multi-dimensional Open-system Photonic Crystals
An electromagnetic (EM) Bloch wave propagating in a photonic crystal (PC) is
characterized by the immittance (impedance and admittance) of the wave. The
immittance is used to investigate transmission and reflection at a surface or
an interface of the PC. In particular, the general properties of immittance are
useful for clarifying the wave propagation characteristics. We give a general
proof that the immittance of EM Bloch waves on a plane in infinite one- and
two-dimensional (2D) PCs is real when the plane is a reflection plane of the PC
and the Bloch wavevector is perpendicular to the plane. We also show that the
pure-real feature of immittance on a reflection plane for an infinite
three-dimensional PC is good approximation based on the numerical calculations.
The analytical proof indicates that the method used for immittance matching is
extremely simplified since only the real part of the immittance function is
needed for analysis without numerical verification. As an application of the
proof, we describe a method based on immittance matching for qualitatively
evaluating the reflection at the surface of a semi-infinite 2D PC, at the
interface between a semi-infinite slab waveguide (WG) and a semi-infinite 2D PC
line-defect WG, and at the interface between a semi-infinite channel WG and a
semi-infinite 2D PC slab line-defect WG.Comment: 8 pages, 6 figure
Milk protein-derived peptide inhibitors of angiotensin-I-converting enzyme
peer-reviewedNumerous casein and whey protein-derived angiotensin-I-converting enzyme (ACE) inhibitory
peptides/hydrolysates have been identified. Clinical trials in hypertensive animals and humans
show that these peptides/hydrolysates can bring about a significant reduction in hypertension.
These peptides/hydrolysates may be classified as functional food ingredients and nutraceuticals
due to their ability to provide health benefits i.e. as functional food ingredients in reducing the
risk of developing a disease and as nutraceuticals in the prevention/treatment of disease
Second-Trimester Placental and Thyroid Hormones Are Associated With Cognitive Development From Ages 1 to 3 Years
Adequate maternal thyroid hormone (TH) is necessary for fetal brain development. The role of placental human chorionic gonadotropin (hCG) in ensuring the production of TH is less well understood. The objective of the study was to evaluate 1) associations of placental hCG and its subunits, and maternal TH in the second trimester, and 2) the single and joint effects of TH and placental hormones on cognitive development and communication at ages 1 and 3 years. Fifty individuals (5%) were selected from the CANDLE (Conditions Affecting Neurocognitive Development and Early Learning) pregnancy cohort in Memphis, Tennessee, with recruitment from 2006 to 2011, to equally represent male and female fetuses. Participants were 68% Black and 32% White. Hormones measured were maternal thyroid (thyrotropin [TSH] and free thyroxine [FT4]) and placental hormones (hCG, its hyperglycosylated form [hCG-h], and free alpha- [hCG alpha] and beta-subunits [hCG beta]) in maternal serum (17-28 weeks). The primary outcome measurement was the Bayley Scales of Infant and Toddler Development. All forms of hCG were negatively associated with FT4 and not associated with TSH. hCG alpha was associated with cognitive development at age 1 year and jointly interacted with TSH to predict cognitive development at age 3 years. This pilot study added insight into the thyrotropic actions of hCG in the second trimester, and into the significance of this mechanism for brain development. More research is warranted to elucidate differences between hCG alpha, hCG beta, and hCG-h in relation to TH regulation and child brain function.Peer reviewe
Sub-microsecond thermal reconfiguration of silicon photonic devices
© 2009 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.DOI: 10.1109/LEOS.2009.5343159Using the experimental data we show the possibility of sub-microsecond reconfiguration of silicon photonics microresonators through pulse shaping of micro-heater excitation. Also, a novel heater structure based on small microdisk resonators with sub-hundred-nanosecond reconfiguration speed is proposed and investigated theoretically
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