Thermoelectric magnetohydrodynamic stirring of liquid metals.

The direct observation of a thermoelectric magnetohydrodynamic (TEMHD) flow has been achieved and is reported here. The origin of the flow is identified based on a series of qualitative tests and corresponds, quantitatively, with a swirling flow TEMHD model. A theory for determining the dominant driver of a free-surface flow, TEMHD or thermocapillary (TC), is found to be consistent with the experimental results. The use of the analytical form for an open geometry develops a new dimensionless parameter describing the ratio of TEMHD to TC generated flows.

Characterization of the glyoxalase I gene from the vascular wilt fungus Verticillium dahliae.

A glyoxalase I gene homologue (VdGLO1) was identified in the vascular wilt fungus Verticillium dahliae by sequence tag analysis of genes expressed during resting structure development. The results of the current study show that the gene encodes a putative 345 amino acid protein with high similarity to glyoxalase I, which produces S-D-lactoylglutathione from the toxic metabolic by-product methylglyoxal (MG). Disruption of the V. dahliae gene by Agrobacterium tumefaciens-mediated transformation resulted in enhanced sensitivity to MG. Mycelial growth of disruption mutants was severely reduced in the presence of 5 mmol/L MG. In contrast, spore production in liquid medium was abolished at 1 mmol/L MG, although not at physiologically relevant concentrations of

Suppression of third-order intermodulation in a klystron by third-order injection.

The first observations and measurements are reported on suppression of the third-order intermodulation (IM3) product arising from nonlinear mixing of two drive frequencies in a klystron, by externally injecting a wave at the IM3 product frequency. Optimum amplitude and phase of the injected wave for maximum suppression are examined. Results indicate that suppression of the IM3 product by as much as 30 dB can be achieved. Experimental results compare favorably with predictions of a 1D simulation code that takes into account all kinematical and dynamical effects including charge overtaking and space charge forces.

Sequence tag analysis of gene expression during pathogenic growth and microsclerotia development in the vascular wilt pathogen Verticillium dahliae.

Two cDNA libraries were constructed from cultures of the vascular wilt fungus Verticillium dahliae, grown either in simulated xylem fluid medium (SXM) or under conditions that induce near-synchronous development of microsclerotia. Expressed sequence tags (ESTs) were obtained for over 1000 clones from each library. Most sequences in the two EST collections were unique; nearly 55% of the translated ESTs had strong similarity to protein sequences in the NCBI nonredundant database. ESTs corresponding to melanin biosynthetic enzymes were exclusive to the developing microsclerotia (DMS) collection, and sequences corresponding to extracellular hydrolases (plant cell wall degrading enzymes) were more abundant in that collection. ESTs corresponding to proteins involved in transport and cell growth were more abundant in the SXM collection. The results of this preliminary analysis suggest that the in vitro growth conditions used here provide useful model systems that will facilitate studies of pathogenesis and microsclerotia development in V. dahliae.

Remote-sensing reflectance determinations in the coastal ocean environment: impact of instrumental characteristics and environmental variability.

Three independent ocean color sampling methodologies are compared to assess the potential impact of instrumental characteristics and environmental variability on shipboard remote-sensing reflectance observations from the Santa Barbara Channel, California. Results indicate that under typical field conditions, simultaneous determinations of incident irradiance can vary by 9-18%, upwelling radiance just above the sea surface by 8-18%, and remote-sensing reflectance by 12-24%. Variations in radiometric determinations can be attributed to a variety of environmental factors such as Sun angle, cloud cover, wind speed, and viewing geometry; however, wind speed is isolated as the major source of uncertainty. The above-water approach to estimating water-leaving radiance and remote-sensing reflectance is highly influenced by environmental factors. A model of the role of wind on the reflected sky radiance measured by an above-water sensor illustrates that, for clear-sky conditions and wind speeds greater than 5 m/s, determinations of water-leaving radiance at 490 nm are undercorrected by as much as 60%. A data merging procedure is presented to provide sky radiance correction parameters for above-water remote-sensing reflectance estimates. The merging results are consistent with statistical and model findings and highlight the importance of multiple field measurements in developing quality coastal oceanographic data sets for satellite ocean color algorithm development and validation.

Hold that x-ray: aspirate pH and auscultation prove enteral tube placement.

We report here a prospective study evaluating an alternative to the roentgenographic confirmation of "fine-bore" nasoenteral feeding tubes. Of 78 nasoenteral intubations in 46 patients using a Dobbhoff (Biosearch Medical Products) weighted enteral feeding tube, gastric aspirates were evaluated in 28. Auscultation was performed in all 78. Data was collected at initial placement prior to x-ray confirmation. Observers used color-coded pH paper to analyze gastric aspirate (pH < or = 4) and/or auscultation of the epigastrium to determine feeding tube position prior to x-rays. Auscultation alone was ineffective as a confirmatory test with only 6.3% specificity (p = 0.31). Aspiration to ascertain tube position was very accurate when pH < or = 4.0 (p = 0.0005) and when it was performed. A pH value of > 4 was not very helpful in predicting malposition (37%) especially when pH altering medications were used. Aspiration of contents was successful in 85% of patients. We conclude that when the pH of the nasogastric tube aspirate is < 4.0, x-ray films are not needed to prove the accuracy of tube placement. In other situations, a film is indicated since auscultation is inaccurate.

Lecithin-cholesterol acyltransferase deficiency: first report of case in a United States citizen.

Lecithin-cholesterol acyltransferase is responsible for the formation of most cholesteryl esters in plasma. Absence of this enzyme can result in a rare syndrome that includes diffuse corneal opacities, normocytic normochromic anemia, proteinuria, renal failure, and premature arteriosclerosis. The deficiency can be inherited in an autosomal recessive manner, or it can be acquired through liver disease. Diagnosis requires a high index of suspicion and documentation of impairment of enzyme mass or activity (or both). This article includes a case report of the first United States citizen known to have lecithin-cholesterol acyltransferase deficiency. The authors review the literature related to this disease.