Mechanistic variations in the oxidation of Piloty's acid by metal complexes

The reactions of N-hydroxybenzenesulfonamide (Piloty's acid, PA) with a variety of metal oxidants are reported. Either nitric oxide or nitrite is the final reaction product, along with benzenesulfinate and the reduced metal compound. The nitrogen product depends on the oxidation potential of the metal oxidant and its ability to further oxidize NO to nitrite. The observation and preliminary interpretation of unusual kinetic behavior of Piloty's acid as a reductant is also described. Analogues of PA were also prepared and found to show similar reactivity.     

Rapid and sensitive handheld biosensor for detection of hantavirus antibodies in wild mouse blood samples under field conditions

Hantavirus cardiopulmonary syndrome (HCPS) is an acute, life threatening viral illness that was first recognized in the spring of 1993 during an outbreak in the Four Corners region of the southwest United States. The etiologic agent, Sin Nombre (SN) virus, is a zoonotic infection that is enzootic in deer mice (Peromyscus maniculatus). Both human and rodent infections lead to specific antibody responses, and detection of such antibodies is the mainstay of diagnosis of infection in both species. More than 300 cases of HCPS have been confirmed in 30 states and four Canadian provinces since 1993 outbreak. Forty percent have been fatal. Conventional methods for the detection of hantavirus antibodies require 4-9 h. Since HCPS can rapidly progress to death, there is a clear need for a rapid diagnostic test. Rapid diagnostic tests for the detection of hantavirus infection should be ideally be (a) quick (b) simple to carry out, (c) allowing if possible for use in field conditions. A field-deployable test would have a particular advantage for diagnosis of infection in wild rodents, such as for risk assessments around case-households, as well as potential human diagnostic applications in battlefield situations. A prototype amperometric immunosensor based on highly dispersed immunoelectrode is developed for operation in field conditions on the importance of rapid and sensitive assay for hantavirus infection in mouse blood serum. This study was initiated to simplify and develop effective procedures for screening rodent serum samples in remote areas. A sandwich scheme immunoassay has been developed and used. Naphthol formed as a result of enzymatic reduction of naphthyl phosphate in the presence of alkaline phosphatase label has been detected amperometrically. The performance of the biosensor device is evaluated by testing mice blood samples in the wild under field conditions. The results were compared with the results obtained using the strip immunoblot assay (SIA) and that obtained from Centers for Disease Control and Prevention (CDC). The overall time of analysis is as low as 25 min and statistical analysis of the data indicated promising results. The device can be easily adapted for fast analysis of other microorganisms under non-laboratory conditions, in remote locations and field operations.     

Identification of volatile (micro) biological compounds from household waste and building materials by thermal desorption–capillary gas chromatography–mass spectroscopy

Volatile compounds from biodegradable household waste and infected building materials have been studied by dynamic or equilibrium headspace sampling and concentration on Tenax TA followed by thermal desorption and HRGC-MS. Equilibrium headspace sampling was also used to study vegetables stored for 14–18 days at ambient temperature. Over 200 compounds were tentatively identified. The concentration of organic sulfur compounds from garden waste was high enough to contribute to respiratory problems of waste handling personnel. Nitriles, alkyl nitro compounds, and alkyl nitrates were isolated from radish and carrot samples at low concentrations (10–50 ppb). Air monitoring in waste handling working environments may be required to ensure the safety of personnel. Branched aliphatic aldehydes, carboxylic acids, esters, and 2-alkanones were found in the headspace of the infected building materials, indicating that volatile compounds may be useful for detection of microbial growth in buildings.     

The determination of cobalt in cobalt-platinum alloys

The separation and analysis of cobalt-platinum alloys by ion exchange or hydrazine reduction are superior to the usual techniques of hydrogen sulfide precipitation or base metal reduction. Cobalt is determined by controlled potential electrodeposition.     

Carbon-13 NMR spectra of a series of para-substituted N,N-dimethylbenzamides. Comparisons of linear free energy relationships for carbon-13 and nitrogen-15 chemical shifts and rotation barriers

All carbon-13 chemical shifts for 11 para-substituted N,N-dimethylbenzamides in 1 mole % chloroform solution are reported, with assignments based upon double resonance experiments, analogy to chemical shifts of benzamide, and self-consistency between experimental and calculated values using recognized substituent parameters. In contrast to earlier reports, the aryl carbon chemical shift assignments for N,N-dimethylbenzamide are C-2, 127.0; C-3, 128.7; C-4, 129.4, and for p-chloro-N,N-dimethylbenzamide are C-1, 134.6; C-4, 135.5 ppm, relative to internal TMS. Good Hammett correlations (σ_p) are reported for ¹³C chemical shifts of C-1 (σ = 11.9 ppm) and even for the carbonyl group (σ = ?2.3 ppm) but are markedly improved if correlated with σ_p+ (σ = 9.5 ppm) and Dewar's F (σ = ?1.9 ppm), respectively. Excellent Swain–Lupton F and R correlations were found for some of the ¹³C chemical shifts and yielded values for percent resonance contributions to transmission of substituent effects as follows, C-1, 75 ± 4%; C-2, 51 ± 3%; C?O, 31±2%. These are compared to similar values calculated from the C?O of benzoic acids of 34±10%, and from the nitrogen-15 chemical shifts of benzamides of 56±2%. Correlations of these ¹³C δ values and ¹⁵N δ values with rotation barriers (ΔG) for N,N-dimethylbenzamides were examined, and it was found that while C?O δ values correlated only poorly the C-1 δ values correlated very well, but the best correlation was for ¹⁵N δ values of benzamides. It is suggested that Δ G and δ ¹⁵N are intrinsically related due to their numerical correlation, and the close similarity in percent resonance contribution of substituent influence on these parameters.     

Comparison of graphite,aluminum, and TransHab shielding material characteristics in a high-energy neutron field

Space radiation transport models clearly show that low atomic weight materials provide a better shielding protection for interplanetary human missions than high atomic weight materials. These model studies have concentrated on shielding properties against charged particles. A light-weight, inflatable habitat module called TransHab was built and shown to provide adequate protection against micrometeoroid impacts and good shielding properties against charged particle radiation in the International Space Station orbits. An experiment using a tissue equivalent proportional counter, to study the changes in dose and lineal energy spectra with graphite, aluminum, and a TransHab build-up as shielding, was carried out at the Los Alamos Nuclear Science Center neutron facility. It is a continuation of a previous study using regolith and doped polyethylene materials. This paper describes the results and their comparison with the previous study.     

Laser desorption fourier transform mass spectra of ascorbic and isoascorbic acids

Positive and negative ion laser desorption Fourier transform mass spectra of ascorbic acid, isoascorbic acid, and their sodium and potassium salts have been determined. A number of differences between these spectra and previously reported laser microprobe mass analyzer (LAMMA) spectra are found. In contrast with earlier results, m/z 175 anions are present in all negative ion spectra, as are cluster ions. Thus, it should not be concluded that the radical salts are electroneutral, as claimed in the earlier study.