The band areas of proteins determined by fluorescent scanning in the commercial automated gel electrophoresis apparatus

An automated gel electrophoresis apparatus, recently available commercially, allows one to follow the band during electrophoresis in real time, and lends itself therefore to an evaluation of bandwidth as a function of migration time (the dispersion coefficient), resolution and band shape. These determinations assume the constancy of band area with migration time and at various gel concentrations. The purpose of the present study was to verify these assumptions. Representative proteins and sodium dodecyl sulfate (SDS)-proteins, either natively fluorescent or fluorescein carboxylate labeled, were found to exhibit band areas which approach constancy as a function of migration time in both agarose and polyacrylamide gel electrophoresis, provided that (i) the protein concentration under the band was low enough to obviate self-quenching of fluorescence; (ii) the separation of the protein of interest from contaminants had progressed sufficiently during the time at which band areas were measured; (iii) the baseline under the peak was sufficiently well defined. However, band areas decrease with increasing gel concentration. Protein peaks exhibited leading and trailing tails. The ratio of the combined tail area to total area appeared to be near-constant at varying migration times. However, that ratio increases with increasing gel concentration. The tail area does not appear to be an artifact of fluorometric detection since it is reproduced upon fluorimetric analysis of the protein eluted from gel slices after electrophoresis. However, it may be due to photochemical destruction under the conditions of repetitive fluorometric peak detection.     

Quantitative prediction of the degree of pollution of effluent from reactive dye mixtures

By using mathematical formulae developed in previous studies, certain pollution parameters of dye effluent obtained from reactive dyeing with a single dye can be predicted with good accuracy. In this study, the degree of pollution of reactive dyeing effluent using dye mixtures was also predicted by other approaches, such as linear and non-linear regression. The prediction accuracy was found to be satisfactory.     

The binding of substrates and inhibitors to the metal center of myoinositol monophosphatase

The synthetic substrate anthraniloyl-beta-glycerol-P binds to myoinositol monophosphatase with a Kd = 5 microM at pH 7.5. The anthraniloyl chromophore, excited at 330 nm, sensitizes the long lived luminescence of bound Tb(III) at 490, 545, 585 and 620 nm. Assuming a mechanism of radiationless energy transfer, the actual distance of separation between the donor-acceptor pair was calculated to be R = 10 A. Tb(III) binds to the monophosphatase with a Kd = 2 microM, whereas Ca-(II) displaces the lanthanide at concentrations above 0.1 mM. The binding studies support the notion that Tb(III), Ca(II) and Mg(II) interact with a common binding site on the protein. Phosphate ion, a strong competitive inhibitor, perturbs the luminescence of bound Tb(III), whereas the substrate beta-glycero-P has no effect on the luminescence yield and long-lived emission of bound Tb(III). It is suggested that the phosphate group of the substrate is not in direct contact with the metal ion coordinated to several amino acid residues of the enzyme.     

Development of the bi-directional ultrasound system for base of tongue imaging

The use of conventional ultrasound systems to image the upper airway has been limited because ultrasound energy is attenuated by the air column. In an attempt to study upper airway geometry, we developed a computer controlled bi-directional ultrasound system which combines two conventional ultrasound devices with computer image processing to yield images of upper airway structures. Human studies and cadaver studies were performed to evaluate the system. Images acquired by the bi-directional ultrasound system were comparable to images from 3D volume rendered CT scans. This system may provide valuable data in the study of upper airway physiology and pathology.     

A systematic design method to obtain broadband characteristics for singly-fed electromagnetically coupled patch antennas for circular polarization

We present a systematic, empirical design technique to obtain optimum broadband impedance, axial-ratio (AR) and gain bandwidths for a singly-fed electromagnetically coupled patch antenna for circular polarization. Our investigation has also revealed tradeoffs amongst obtainable AR, impedance bandwidth and AR bandwidth. Using two design examples at different frequency bands and for different senses of circular polarization, we have demonstrated the effectiveness of the proposed knowledge-based tuning method. We have obtained at C-band measured values of impedance bandwidth (VSWR/spl les/2) equal to 43%, 3-dB AR bandwidth of 8%, AR of less than 0.3 dB and a mean gain level of 7 dB. For the Ku-band element, a 40% impedance bandwidth and a 17.3% of 3-dB AR bandwidth have been obtained with a peak gain of 7.2 dBic.     

Prediction of residual colour in reactive dyeing effluent

In this study, the absorbance of the three-dye mixture effluent from reactive dyeing has been used to predict the residual colour value of the dyeing effluent. The colour values of the dyeing effluent have been predicted in terms of ADMI colour values. The prediction accuracy was found to be satisfactory when some mathematical approaches, such as linear and non-linear regression, were used.     

Diode-HBT-logic circuits monolithically integrable with ECl/CMLcircuits

A novel logic approach, diode-HBT logic (DHL), that is implemented with GaAlAs/GaAs HBTs and Schottky diodes to provide high-density and low-power digital circuit operation is described. This logic family was realized with the same technology used to produce emitter-coupled-logic/current-mode-logic (ECL/CML) circuits. The logic operation was demonstrated with a 19-stage ring oscillator and a frequency divider. A gate delay of 160 ps was measured with 1.1 mW of power per gate. The divider worked properly up to 6 GHz. Layouts of a DHL flip-flop and divider showed that circuit area and transistor count can be reduced by about a factor of 3, relative to ECL/CML circuits. The new logic approach allows monolithic integration of high-speed ECL/CML circuits with high-density DHL circuits with high-density DHL circuits     

Plasma lens experiment at the final focus test beam

The proposed plasma lens experiment at the Final focus Test Beam (FFTB) facility of the Stanford Linear Accelerator Center has been approved by the adminstration. The experiment would allow the examination of plasma focusing devices for particle beams in the parameter regime of interest to future high-energy colliders. It is expected to lead to compact plasma lens designs capable of focusing the beam to unprecedented small spot sizes.     

Consequences of the formation of Cooper-pairs near oxygen-deficient sites

In this investigation we consider the formation of Cooper pairs near the oxygen-deficient sites in Y-Ba-Cu-O ceramic superconductors which would give rise to an energy-dependent potential as seen by conduction charge carriers. It is shown that Cooper pairs could be formed under such conditions, resulting in a supercurrent. We use the Bogoliubov transformation technique to calculate the energy gap, the energy difference, and the transition temperature of the model superconductor using certain data obtained from previous experiments. Numerical analysis shows that the superconducting current can be explained by the presence of such oscillating Cooper pairs.