Parallel curves: getting there and getting back

This note takes up the issue of parallel curves while illustrating the utility of Mathematica in computations. This work complements results presented earlier. The presented treatment, considering the more general case of parametric curves, provides an analysis of the appearance of cusp singularities, and emphasizes the utility of symbolic algebra systems.     

A rapid solid-phase fluorescence-based protein assay for quantitation of protein electrophoresis samples containing detergents, chaotropes, dyes, and reducing agents

A new solid-phase, fluorescence-based protein assay was developed that quantifies proteins in the presence of detergents, urea and reducing agents (one-dimensional sodium dodecyl sulfate (1-D SDS) lysis buffers and urea isoelectric focusing (IEF) buffers). A specially designed 96-well microplate facilitates application of protein samples to the assay paper and allows easy quantitation of samples using fluorescence microplate readers (top or bottom reading format). Alternatively, stained membranes may be directly scanned using a variety of different laser or charge-coupled device (CCD)-based imaging devices with UV or visible imaging capabilities. Since protein is specifically bound to the membrane, contaminants are readily washed away, avoiding interference with the protein measurement. The protein assay has a dynamic range extending from 10 ng to 5 microg of protein per microliter and requires only 1 microL of sample, which is ideal for samples destined for electrophoresis. The protein-to-protein variability of staining of ten different proteins was determined to be comparable with that of the bicinchoninic acid (BCA) and Lowry assays (16%). Additionally, the quality of the assay according to Z-factor analyses is excellent.     

Synthesis of 4,5-dihydro-4-phenyl-3H-1,3,4-benzotriazepines

Several 4,5-dihydro-4-phenyl-3H-1,3,4-benzotriazepines were synthesized by conversion of 1-[(2-nitrophenyl)methyl]-1-phenylhydrazine to either 1-[(2-aminophenyl)methyl]-1-phenylhydrazine or 1-[(2-aminophenyl)-methyl]-2-methyl-1-phenylhydrazine. Ring closure of these intermediates with triethyl orthoacetate or triethyl orthopropionate gave the title compounds in overall yields of 40-60%.     

13C-Nmr spectra of anhydro-3-mercapto-5-pyrazinyl-1,2,4-triazolium hydroxides

The complete assignment of the ¹³C-nmr spectra of some anhydro-3-mercapto-5-pyrazinyl-1,2,4-triazolium hydroxides (1) is reported. For purposes of comparison the spectra of some isomeric triazole-3-thiones ( 2 ) are also reported. Positions C-3 and C-5 of the triazole ring and 2′ of the pyrazine moiety were found to be characteristic of each group of compounds.     

In silico targeting PAD4 for the treatment of rheumatoid arthritis

Structural Chemistry - Rheumatoid arthritis (RA) is an autoimmune disorder that causes chronic inflammation with periodic bursts of activity in multiple synovial joints which lead to irreversible...     

Nuclear orbiting and anomalies in nuclear reactions

In this paper, we report our measurements of back-angle oxygen and carbon particle yields from ¹⁶O+⁸⁹Y, ¹²C+⁹³Nb reactions forming the same compound nucleus ¹⁰⁵Ag at the same excitation energy and spin distribution. We find anomalously large oxygen yield and entrance channel dependence at high excitation energies from ¹⁶O+⁸⁹Y reaction implying formation of a dinuclear orbiting complex. Possible connection between nuclear orbiting and fast fission is also discussed.     

Computer models of hearing aid transducers for integrated circuit design.

Electronic circuit modeling using computer-based simulation tools is well established and device models are available for common electronic components. However, acoustic models of audio transducers for use during integrated circuit design are not readily available. This causes difficulty for designers of audio amplifiers, and increases the uncertainties of a successful silicon integration of a circuit design. This paper reports on a technique for the creation of electroacoustic models of hearing aid microphones and receivers that can be connected to an amplifier under design, and incorporated into PSPICE simulations. Verification of the technique and models was performed by comparing measured frequency response data with graphs created by PSPICE modeling. The conclusions were that the method developed for creating these models, and the models themselves, were accurate enough to be used for acoustic simulations of frequency response performance during amplifier design, and gave results comparable to data obtained from breadboard measurements of the same circuits.