Theory and Applications of Surface Plasmon Resonance, Resonant Mirror, Resonant Waveguide Grating, and Dual Polarization Interferometry Biosensors

Biosensors have been used extensively in the scientific community for several purposes, most notably to determine association and dissociation kinetics, protein-ligand, protein-protein, or nucleic acid hybridization interactions. A number of different types of biosensors are available in the field, each with real or perceived benefits over the others. This review discusses the basic theory and operational arrangements of four commercially available types of optical biosensors: surface plasmon resonance, resonant mirror, resonance waveguide grating, and dual polarization interferometry. The different applications these techniques offer are discussed from experiments and results reported in recently published literature. Additionally, recent advancements or modifications to the current techniques are also discussed

On The Financial Characteristics Of Firms That Have Achieved The Highest Levels Of Accuracy In Earnings Predictability

The value of a company is said to be a function of the future earnings or cash flows the company will produce discounted at a rate commensurate with risks associated with those cash flows. The subject of earnings predictability or the lack of reliable forecasts has been of interest to academic researchers and financial managers for years. Value Line publishes weekly, a ranking of the reliability of earnings predictions for every firm in their database. The higher the Value Line ranking for earnings predictability, the more likely they would recommend it as a safe investment. Earnings predictability is then, simply one of their important measures of potential value and safety.  The purpose of this study is to provide a financial analysis of those firms described by Value Line as having the most reliable levels of earnings predictability in their database. Specifically, the analysis will test for significant differences in the financial profiles of those firms that achieved the highest Value Line ratings for earnings predictability, and companies selected at random from the same industries.  A unique financial profile is estab­lished for the highest rated group, and it is suggested that the profile may be used to identify firms that because of their financial nature are capable of producing the most accurate sales forecasts, and earnings predictability. As in previous studies of this nature Multiple Discriminant Analysis is used.&nbsp

BIOPHYSICAL AND PHARMACOLOGICAL CHARACTERIZATION OF CYTOPLASMIC DYNEIN HEAVY CHAIN 1

The cytoplasmic dynein motor protein complex transports a number of different important cargos along microtubules (MTs) in a retrograde manner. Cytoplasmic dynein plays an important role in many cellular processes and a number of diseases have been associated with defects in its activity. Despite its importance, there are no small molecules that selectively modulate cytoplasmic dynein activity, nor is its atomic structure elucidated. In an effort to identify compounds that target cytoplasmic dynein, hits from a high information content cell-based nuclear translocation assay were further evaluated biochemically. High throughput assays were developed to screen for glucocorticoid ligand competition, MT perturbation, and the ATPase activities of Hsp 70 and 90, cytoplasmic dynein heavy chain 1, and myosin. Several compounds from screening the Library of Pharmacologically Active Compounds (LOPAC1280) were identified to inhibit cytoplasmic dynein, though they had several unattractive pharmacological properties and were generally non-specific. Additional screening of the Molecular Libraries Screening Center Network >220,000-member library showed a number of compounds that specifically inhibited the ATPase activity of cytoplasmic dynein heavy chain 1 with little or no interaction with other proteins involved in cargo complex formation. A novel approach to screen for MT perturbing agents was also developed using biosensors. Thickness, mass, and density measurements from dual polarization interferometry suggested the growth process of MTs on surfaces. Resonant mirror biosensors were used to distinguish MT stabilizers from destabilizers based on rates of MT assembly on the surfaces.In addition, the structure of the cytoplasmic dynein heavy chain motor domain was characterized by computational and experimental methods. Comparative homology structural modeling was used to predict 15 surface accessible cysteines, which were then correlated experimentally by mass spectrometry. Five cysteines were matched computationally and experimentally to be surface-accessible, suggesting some inadequacy of the proposed model. Finally, attempts to reconstruct a model of cytoplasmic dynein heavy chain 1 by electron microscopy were hindered by the purification of the protein from both a Hi5/baculovirus expression system and bovine brain, although the latter appeared to provide better quality micrographs. Ultimately, structural characterization will assist with the discovery of cytoplasmic dynein heavy chain 1 modulators

The Gln27Glu Polymorphism in β2-Adrenergic receptor gene is linked to hypertriglyceridemia, hyperinsulinemia and hyperleptinemia in Saudis

<p>Abstract</p> <p>Background</p> <p>β2-adrenoceptor (β2AR) gene polymorphism glutamine 27 glutamic acid (Gln27Glu) and Arg16Gly were reported to have an association with obesity and obesity related disorders in some population. We evaluated Gln27Glu polymorphism in the β2AR gene in obese Saudi populations to investigate the association of β2AR gene with obesity and other related metabolic parameters.</p> <p>Design</p> <p>We studied possible association of Gln27Glu in β2AR gene with body mass index (BMI), anthropometric measurements and other metabolic parameters. The β2AR gene polymorphism (Gln27Glu) was identified by sequencing PCR products representing locus of interest. Based on BMI, the subjects were divided into three groups, normal weight, overweight and obese. The genotype and allele frequency were calculated separately for each group.</p> <p>Results</p> <p>The allelic frequency of Glu27 did not differ amongst the three groups, though the Glu27 homozygote (Glu/Glu) were more in obese subjects and had higher concentration of triglyceride, leptin and insulin compared to in the Gln27 heterozygotes and Gln/Gln homozygotes.</p> <p>Conclusions</p> <p>In this study we were able to provide evidence on the influence of Gln27Glu genetic variant of β2AR gene on lipid phenotypes, insulin and leptin levels in the Saudi populations.</p

Bisphenol A Detection in Various Brands of Drinking Bottled Water in Riyadh, Saudi Arabia Using Gas Chromatography/Mass Spectrometer

Purpose: To assess whether bisphenol A contamination occurred in seven brands of bottled drinking water in Riyadh, Saudi Arabia.Methods: Liquid-liquid extraction (using dichloromethane) was used to analytically extract bisphenol A from drinking water bottles and a gas chromatograph-mass spectrometer was employed for its detection using a splitless capillary column and helium as the carrier gas.Results: The concentration of bisphenol A (BPA) was high in all the bottled water brands tested. The mean concentration of BPA of the bottled water stored indoors (4.03 ng/L) was significantly lower than that stored outdoors (7.5 ng/L).Conclusion: Our results show that significant amounts of BPA leached from bottle containers into the water. Long storage of bottled water under direct sunlight should be avoided to reduce the risk of human exposure to BPA

Serum N-propeptide of collagen IIA (PIIANP) as a marker of radiographic osteoarthritis burden

Cartilage homeostasis relies on a balance of catabolism and anabolism of cartilage matrix. Our goal was to evaluate the burden of radiographic osteoarthritis and serum levels of type IIA procollagen amino terminal propeptide (sPIIANP), a biomarker representing type II collagen synthesis, in osteoarthritis

Stimuli-responsive 2D polyelectrolyte photonic crystals for optically encoded pH sensing.

A versatile photonic crystal sensing motif based on a twodimensional (2D) inverse opal monolayer of stimuli-responsive polyelectrolyte gel with tunable optical properties is reported. The photonic membrane shows prompt response to pH and can be readily read out from either its optical spectra or interference colours

Light assisted antibody immobilization for bio-sensing

Ultrashort UV pulses at 258 nm with repetition rate of 10 kHz have been used to irradiate buffer solution of antibody. The tryptophan residues strongly absorb this radiation thus becoming capable to disrupt the disulfide bridges located next to them. Due to their high reactivity the opened bridges can anchor a gold plate more efficiently than other sites of the macromolecule giving rise to preferential orientations of the variable part of the antibody. UV irradiation has been applied to anchor antiIgG antibody to the electrode of a Quartz Crystal Microbalance (QCM) that lends itself as a sensor, the antibody acting as the bio-receptor. An increase of the QCM sensitivity and of the linear range has been measured when the antibody is irradiated with UV laser pulses. The photo-induced reactions leading to disulfide bridge breakage have been analyzed by means of a chemical assay that confirms our explanation. The control of disulfide bridges by UV light paves the way to important applications for sensing purpose since cysteine in combination with tryptophan can act as a hook to link refractory bio-receptors to surfaces