Pesticide activity of foods exposed to naled or dichlorvos PVC resin formulations

Raw hamburger, fruits, vegetables and bread were exposed to a 25% naled-polyvinyl chloride resin formulation and a comparable commercial 20% dichlorvos formulation in test cells for 24 hr. Relative pesticide activity was determined by bioassay (lt₅₀) against male SRS susceptible houseflies (Musca domestica L.). Activity in samples exposed to dichlorvos was 11 to 16 times greater than that in comparable naled samples and treatments. Since housefly topical ld₅₀ values for these 2 organophosphates are nearly similar, a much smaller residue of naled is indicated by greater lt₅₀ of food exposed to this pesticide.     

Pyroelectric microcalorimetry

We have been measuring the bulk electrical and thermal properties of the quantum ferroelectric KTa_0.992Nb_0.008O₃ (KTN) in the interest of making a thermal sensor for a pyroelectric microcalorimeter. The pyroelectric coefficient and specific heat of KTN as a function of temperature and electric field are given. The measurements indicate that a thin film detector with the same pyroelectric coefficient as that found in our sample would in principle be able to operate in a phonon noise limited regime over a wide bandwidth.     

Analog Signal Processing for the Time Projection Chamber

The Time Projection Chamber (TPC) is a large gas filled cylindrical detector designed to provide 3-D images of tracks radiating from the center of the detector where e+ e- collisions occur. Ionization along the tracks is drifted in an electric field to the end planes which are equipped with a large array of proportional wires and position pads (17,000 channels). The wire signals are used to derive radial data while the pad signals provide the azmuthal information. The axial dimension is determined using the drift time of the ionization. Preamplifiers mounted in the ends of the chamber feed the signals to remote amplifiers whose outputs drive Charge Coupled Devices (CCD). The CCDs are normally clocked at 10 MHz and hold a 45.5 ?s history (445 CCD buckets) of analog drift information from the TPC. During readout the clock is changed to 20 KHz and 17,000 CCD outputs are digitized (9 bits) in parallel. The non-zero data is then transferred to buffer memories associated with the digitizers. This paper emphasizes the analog signal processing part of the system.     

Experiments and nuclear measurements in search of cold fusion processes

This paper reports a collaborative effort of a team which formed at Los Alamos to investigate the announcement that cold fusion may be occurring in electrochemical cells using palladium cathodes and platinum anodes in a LiOD electrolyte. Four electrochemical cells were construced and operated for 3–5 weeks under various geometrical and electrical conditions. Nuclear diagnostic measurements included high and low resolution gamma-ray spectroscopy, integral neutron counting with well detectors and banks of³He tubes, and neutron spectroscopy withNE-213 scintillators. For one of the cells, the deuterium loading of the cathode was determined from resistance measurements to beD/Pd 0.8. No conclusive evidence was found for the production of neutrons or 2.223-MeV gammas above levels consistent with background. The results of the measurements of tritium levels in the cell electrolytes are also reported. Experiments to reproduce the observation of neutrons from high pressureTi-D ₂ gas experiments were also performed with negative results.Work supported by the U.S. Department of Energy under contract with the University of California.     

A first demonstration and analysis of the biprimary color system for reflective displays

A new biprimary color system is demonstrated for single‐layer reflective displays, capturing much of the improved color performance of multilayer displays while potentially maintaining single‐layer display advantages in high resolution and faster switching. Electrophoretic pixels were operated with dual‐particle complementary‐colored dispersions such as green/magenta (G/M). Using simple interdigitated three‐electrode architecture, four colored states (KWGM) were achieved with a preliminary contrast ratio of 10 : 1. Furthermore, biprimary ink dispersions were shown to be functional in a more advanced electrokinetic pixel structure. A full‐color biprimary pixel contains three complementary subpixels (G/M, B/Y, R/C), and the requisite electrophoretic ink dispersions were also formulated and spectrally characterized in this work. Lastly, theoretical color space mapping confirms that the biprimary concept provides twice the brightness and twice the color fraction compared with the conventional RGBW subpixel approach, and that the biprimary concept can approach performance close to that of magazine print (Specifications for Web‐Offset Print).     

“Honeymoon” fast-setting adhesives for timber laminating

1. Aim of research Proving the industrial suitability of phenolic honeymoon-fast-setting-adhesives surface-grain gluing.
2. Method The adhesives were used in an automated high-speed laminating press to industrially manufacture 36 mm thick edge joints at high speed.
3. Results The joints obtained satisfied the requirements of the specifications SABS 876/1976 and 1349/1981, and BS 1204/1965. Production times were twice as fast as those obtainable with conventional phenol-resorcinol-formaldehyde adhesives.

     

Cobalamin-dependent methionine synthase from Escherichia coli: involvement of zinc in homocysteine activation

Methionine synthase (MetH) is a modular protein with at least four distinct regions; amino acids 2-353 comprise a region responsible for binding and activation of homocysteine, amino acids 345-649 are thought to be involved in the binding and activation of methyltetrahydrofolate, amino acids 650-896 are responsible for binding of the prosthetic group methylcobalamin, and amino acids 897-1227 are involved in binding adensylmethionine and are required for reductive activation of enzyme in the cob(II)alamin form. Previous studies have shown that mutations of Cys310 or Cys311 to either alanine or serine result in loss of all detectable catalytic activity. These mutant proteins retain the ability to catalyze methyl transfer from methyltetrahydrofolate to exogenous cob(I)alamin, but have lost the ability to transfer methyl groups from exogenous methylcobalamin to homocysteine [Goulding, C. W., Postigo, D., and Matthews, R. G. (1997) Biochemistry 36, 8082-8091]. We now demonstrate that both MetH holoenzyme and a truncated MetH(2-649) protein, which lacks a cobalamin prosthetic group, contain 0.9 equiv of zinc, while the Cys310Ser and Cys311Ser mutant proteins contain less than 0.05 equiv of zinc. Addition of l-homocysteine to MetH(2-649) is accompanied by release of 1 equiv of protons/mol of protein, while addition of l-homocysteine to the Cys310Ser and Cys311Ser mutant truncated proteins does not result in proton release. The Cys310Ala and Cys311Ala mutant methylcobalamin holoenzymes have completely lost the ability to transfer the methyl group from methylcobalamin to homocysteine, suggesting that zinc is required for this reaction. Further evidence that zinc is required for catalytic activity comes from experiments in which the zinc is removed from MetH(2-1227). Removal of zinc from methylated wild-type holoenzyme by treatment with methyl methanethiolsulfonate and then with dithiothreitol and EDTA results in loss of the ability of the protein to catalyze methyl transfer from methyltetrahydrofolate to homocysteine. Reconstitution of the zinc-depleted holoenzyme results in incorporation of 0.4 equiv of zinc/mol of protein and partial restoration of the ability of the protein to catalyze homocysteine methylation.     

A histopathological comparison of the uvula between snorers and non-snorers

To study the specificity of serum antibodies against filamentous hemagglutinin (FHA) and pertactin for infection with Bordetella pertussis, we followed the acquisition of IgG serum antibodies against these 2 surface proteins of the organism in children who had been vaccinated with a monocomponent pertussis toxoid vaccine and who had experienced no symptoms of pertussis. Antibodies were estimated with enzyme-linked immunosorbent assay. In Part 1 of our study 5 consecutive samples obtained between 3 and 36 months of age from 71 children were available. Most had maternally derived antibodies to FHA (70 of 71) and pertactin (51 of 71) in the 3-month sera which declined in the subsequent sera. From about 1 year of age there were small but significant increases in antibodies against both antigens. At 3 years of age 71 of 71 had antibodies to FHA and 58 of 71 had antibodies to pertactin. In Part 2 of our study sera from 109 three-year old children were available. The 12 children with a history of family exposure to pertussis had significantly higher geometric mean titers of FHA antibodies than the 97 children with no history of family exposure. The geometric mean titers of pertactin antibodies did not differ. We suggest 3 explanations for the acquisition of FHA and pertactin antibodies in children with no history of pertussis: (1) asymptomatic B. pertussis infection in vaccinated children; (2) infection with Bordetella parapertussis; (3) infection with cross-reacting antigens from other organisms, e.g., nonencapsulated Haemophilus influenzae.