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This paper reports on the characterization and preliminary comparison of gold nanoparticles of differing surface modification and shape when used as extrinsic Raman labels (ERLs) in high-sensitivity heterogeneous immunoassays based on surface enhanced Raman scattering (SERS). ERLs are gold nanoparticles coated with an adlayer of an intrinsically strong Raman scatterer, followed by a coating of a molecular recognition element (e.g., antibody). Three types of ERLs, all with a nominal size of ~30 nm, were fabricated by using spherical citrate-capped gold nanoparticles (sp-cit-Au NPs), spherical CTAB-capped gold nanoparticles (sp-CTAB-Au NPs), or cubelike CrAB-capped gold nanoparticles (cu-CrAB-Au NPs) as cores. The performance of these particles was assessed via a sandwich immunoassay for human IgG in phosphate buffered saline. The ERLs fabricated with sp-CTAB-Au NPs as cores proved to be more than 50 times more sensitive than those with sp-cit-Au NPs as cores; the same comparison showed that the ERLs with cu-CTAB-Au NPs as cores were close to 200 times more sensitive. Coupled with small differences in levels of nonspecific adsorption, these sensitivities translated to a limit of detection (LOD) of 94, 2.3, and 0.28 ng/mL, respectively, for the detection of human IgG in the case of sp-cit-Au NPs, sp-CrAB-Au NPs, and cu-CTAB-Au NPs. The LOD of the cu-CrAB-Au NPs is therefore ~340 times below that for the sp-cit-Au NPs. Potential applications of these labels to bioassays are briefly discussed.

Studies done on the stability and catalytic activity of the PVP-Pt nanoparticle during its catalytic function for the electron-transfer reaction between hexacyanoferrate(III) ions and thiosulfate ions is presented. Studies reveal that the hexacyanoferrate(III) ions alone dissolve the Pt from the nanoparticle surface to form a cyano complex, as expected from thermodynamic considerations whereas thiosulfate seems to bind to the nanoparticle surface.

Human Action Recognition (HAR) is a highly notable area of study in contemporary computer vision. Many investigations focused on recognizing a person's actions from video streams based on extracting features regarding orientation and motion. This article presents a Joints and Trajectory-pooled 3D-Deep Positional Attention (PA)-based Hierarchical Bidirectional Recurrent Convolutional Descriptors (JTDPAHBRD) approach which uses a PA-based Hierarchical Bidirectional Recurrent Neural Network (PAHBRNN) for enhancing the feature aggregation process. First, the entire video is segregated into multiple blocks and they are provided to the 2-stream bilinear Convolutional 3D (C3D) model which applies the PAHBRNN as feature aggregation. In PAHBRNN, the feature vectors related to the different parts of a human skeleton in a certain clip are hierarchically aggregated using the position-aware guidance vector. Then, 2 different streams in the C3D network are fused and trained end-to-end using the softmax loss to get the final video descriptor for a particular video sequence. Further, the Support Vector Machine (SVM) classifier is applied to classify the resultant video descriptor to recognize the person's actions. At last, the investigational outcomes demonstrate the JTDPAHBRD achieves 99.6% better recognition accuracy than the classical state-of-the-art approaches. [ABSTRACT FROM AUTHOR]

Sucrose concentration can be easily measured in the chemistry class using a liquid prism sucrosemeter, made from a hollow prism filled with liquids with different refractive indices from changes in sucrose concentration. Thirteen concentrations and one water solution are used in the experiment with a table of the experimental values provided.

The work on the effect of the shape of the colloidal nanocatalyst on the catalytic activity and the effect of the catalytic process on the shape and size of the colloidal transition metal of the nanocatalysts and their recycling potential is reviewed. It provides important clues on the mechanism of the reactions that is studied and can be very useful in the process of designing better catalysts in the future.

The synthesis and properties of individual nanoparticles is described. The richness and maturity that nanoscience and nanochemistry in particular has achieved in the past few years is demonstrated.

FTIR is used to examine the change in the vibrational frequencies of phenylboronic acid in the films with and without the addition of palladium nanoparticles. The FTIR studies provide proof the mode of binding that occurs in the nanoparticle surface for the first time and also confirms the mechanism of the Suzuki reaction.

The stability and catalytic activity of PAMAM-OH generation 4 dendrimer-capped Pd nanoparticles are examined and compared to those of the PVP-Pd nanoparticles. Thus, the ways in which the method of synthesizing the nanoparticles affects the particle growth process, how the capping agent affects the mechanism of the reaction, and how the size of the nanoparticles during the second cycle of the reaction affects the biphenyl product yield, are studied.

The activation energies for the electron-transfer reaction between hexacyanoferrate (III) ions and thiosulfate ions in a colloidal solution in which tetrahedral, cubic, or spherical nanoparticles are dominant. The tetrahedral and cubic shapes strive to become spherical, the thermodynamic reason for their shape changes during the catalytic reaction.

A study was conducted to examine and compare the shape stability of tetrahedral and cubic platinum nanoparticles used to catalyze the electron-transfer reaction between hexacyanoferrate ions and thiosulfate ions to form hexacyanoferrate ions and tetrathionate ions. The result confirms that the rate of dissolution of the surface platinum atoms is slower for the cubic shaped nanoparticles than for the tetrahedral shaped nanoparticles.

An inexpensive refractometer for determining the lateral displacement of a light beam through various liquids can be used in both high school and introductory college chemistry courses as well as for a take-home experiment. The refractometer gives students practice in geometrical optics and ray tracing as well as assembling the refractometer itself. Construction and experiment directions are included.

Abstract: The reaction of amino groups of protein and the carbonyl groups of reducing sugar molecules, non-enzymatically induce a series of chemical reactions that form a heterogeneous group of compounds known as advanced glycation end products (AGEs). The accumulation of AGEs is associated with various disease conditions that include complications in diabetes, Alzheimer’s disease and aging. The current study monitored the extent of non-enzymatic glycation of human serum albumin (HSA) in order to estimate the formation of HSA related AGEs in the presence of 2nm gold nanoparticles. The rate of glycation was evaluated using several analytical methods. Physiological concentrations of HSA and glyceraldehyde mixtures, incubated with various concentrations of negatively charged 2nm gold nanoparticles, resulted in a lower reaction rate than mixtures without 2GNP. Moreover, increasing concentrations of gold nanoparticles exhibited a pronounced reduction in AGE formation. High performance liquid chromatography, UV–visible spectroscopy and circular dichroism analytical methods provide reliable techniques for evaluating AGE formation of HSA adducts. [Copyright &y& Elsevier]