Quantitative analysis of cumulative trauma risk factors and risk factor interactions.

This study identifies the strongest occupational risk factors and risk factor interactions in the development of indicators associated with cumulative trauma disorders (CTD). Suggestions for minimizing the occurrence of indicators associated with onset of CTD are presented. Five Occupational risk factors and six risk factor interactions were evaluated to determine their contribution to accepted indicators of the onset of CTD, including exertion, discomfort, difficulty, and fatigue. Taguchi's level-analysis procedure was used to design a 16-trial hammering experiment and to analyze the results. From the hypothesized occupational risk factors, repetition was found to have the strongest effect on the values of the physiological and subjective indicators of the onset of CTD.

An investigation of respiration while wearing back belts.

The research was conducted to evaluate the frequency of respiration during a repetitive lifting task when abdominal compression occurs from wearing a back belt. Three back belts were evaluated in this study: a nylon back belt, an inflatable back belt and an elastic vest. Analysis of the data revealed that the frequency of respiration increased while wearing the back belts at rest and while performing a repetitive lifting task. A statistically significant increase in the frequency of respiration was found while wearing the nylon back belt during the lifting task.

Conservative management of childhood orbital lymphangioma.

Repeated partial excisions are commonly performed for orbital lymphangiomas. Even with the advent of carbon dioxide (CO2) laser as an adjunct to subtotal excision, surgical complications remain common. The authors report six cases of childhood orbital lymphangioma, biopsy proven in five, in which conservative management of recurrent hemorrhage without additional surgery resulted in subsidence of proptosis and return of 20/20 visual acuity. Surgical aggressiveness for recurrent hemorrhages must be tempered by the knowledge that normal vision often results from cautious observation alone.

Seep oil and gas in gulf of Mexico slope sediment.

Concentrations in Gulf of Mexico slope sediment of material soluble in methanol and benzene as high as 4.5 percent are shown to be attributable to biodegraded petroleum. Associated carbonate deposits and organic sulfur are the products of the microbial oxidation of petroleum and sulfate reduction. The results of chemical and carbon isotope analyses indicate that high concentrations of hydrocarbon gases, from methane to pentane, are petroleum rather than microbiologically derived. These hydrocarbons, believed to have been produced thermally at depth, probably reached the surface through faults and fractures associated with salt diapirs.

Mass spectrometric 13C/12C determinations to detect high fructose corn syrup in orange juice: collaborative study.

The 13C/12C ratios in orange juice are sufficiently uniform and different from those in high fructose corn syrup (HFCS) so that the addition of HFCS to orange juice can be detected. HFCS averages -9.7% (parts per thousand) delta 13C, orange juice averages -24.5%, and mixtures of HFCS and orange juice possess intermediate values. One pure orange juice and 4 orange juice -HFCS mixtures containing from 25 to 70% orange juice were properly classified by 7 collaborators. Samples with delta 13C values less negative than -22.1%, 4 standard deviations from the mean of pure juices, can, with a high degree of confidence, be classified as adulterated. Samples with values more negative than -22.1% must be considered unadulterated with HFCS, because pure orange juices possess a range of delta 13C values. The 13C/12C mass spectrometric method was adopted official first action for detecting HFCS in orange juice.

HMO success: product of teamwork and competition.

General Mills and other large corporations in Minneapolis joined forces to build the Twin City Health Care Development Project. The ultimate result was translated at the bottom line--greater health, productivity, and overall corporate well-being.

Carbon isotope fractionation by ribulose-1,5-bisophosphate carboxylase from various organisms.

Carbon isotope fractionation by structurally and catalytically distinct ribulose-1,5-bisphosphate carboxylases from one eucaryotic and four procaryotic organisms has been measured under nitrogen. The average fractionation for 40 experiments was -34.1 per thousand with respect to the delta(13)C of the dissolved CO(2) used, although average fractionations for each enzyme varied slightly: spinach carboxylase, -36.5 per thousand; Hydrogenomonas eutropha, -38.7 per thousand; Agmenellum quadruplicatum, -32.2 per thousand; Rhodospirillum rubrum, -32.1 per thousand; Rhodopseudomonas sphaeroides peak I carboxylase, -31.4 per thousand; and R. sphaeroides peak II carboxylase, -28.3 per thousand. The carbon isotope fractionation value was largely independent of method of enzyme preparation, purity, or reaction temperature, but in the case of spinach ribulose-1,5-bisphosphate carboxylase fractionation, changing the metal cofactor used for enzyme activation had a distinct effect on the fractionation value. The fractionation value of -36.5 per thousand with Mg(2+) as activator shifted to -29.9 per thousand with Ni(2+) as activator and to -41.7 per thousand with Mn(2+) as activator. These dramatic metal effects on carbon isotope fractionation may be useful in examining the catalytic site of the enzyme.

Oxygen Isotope Fractionation during Photosynthesis in a Blue-Green and a Green Alga.

Oxygen isotope fractionation ((18)O/(16)O) at the natural abundance level has been measured during photosynthesis of a blue-green and a green alga. When sufficient attention is paid to removal of contaminating air O(2) before and during the experiments, then the photosynthetic O(2) evolved, as compared to the water O(2), had an average difference of -0.36% for a blue-green alga and -0.80% for a green alga. These experiments suggest that there is no reason to invoke an inverse isotope effect in photosynthesis as part of the explanation for the (18)O enrichment in atmospheric O(2) relative to O(2) in oceanic waters. In addition, in an indirect way, the experiments also support the argument that the bulk of O(2) evolved during photosynthesis comes from water. A 10% contribution of O(2) arising from CO(2) would have been detectable in the present work.

Biochemical effects of technetium-99-pertechnetate on microorganisms.

The biochemical effects of technetium-99 as pertechnetate (TcO(4) (-)) were investigated in a variety of microorganisms (a nonsulfur purple bacterium, five blue-green algae, a protozoan, a diatom, two heterotrophic bacteria, a red alga and two green algae). Sensitivity to pertechnetate as measured by growth ranged from marked inhibition at 1 mug Tc/ml (nonsulfur purple bacterium) to no effect at 600 mug Tc ml (both green algae). No correlation between organism type and growth susceptibility to pertechnetate was apparent. The blue-green alga, Agmenellum quadruplicatum strain PR-6, bound technetium-99 to a level of 3 mug/mg dry weight cells (from medium containing 1.5 mm pertechnetate) in the light, but little or none in the dark; cell death occurred only with uptake. Addition of TcO(4) (-) to the medium caused a rapid but temporary increase in ATP levels of PR-6 (in the light only) and Tetrahymena pyriformis strain WH14. Respiration of organisms WH14 and Bacillus subtilis and photosynthesis of organism PR-6 were immediately slowed by the introduction of pertechnetate. Technetium as pertechnetate has a possible biochemical effect on cells, unrelated to its radioactivity or to a general oxidation effect.

Role of reduced exogenous organic compounds in the physiology of the blue-green bacteria (algae): photoheterotrophic growth of a "heterotrophic" blue-green bacterium.

Nostoc sp. (strain Mac) was shown to be capable of using glucose, fructose, or sucrose as a sole source of carbon and energy in the dark. In the light in the absence of exogenously supplied CO(2), this strain exhibited a more versatile metabolism. In addition to the three sugars above, glycerol and acetate served as sole sources of carbon. This photoheterotrophic growth in the absence of exogenously supplied CO(2) appears to involve O(2)-evolving photosynthesis. The action spectrum for photoheterotrophic growth on acetate closely resembles the action spectrum for photosynthesis. The physiology of photoheterotrophic growth was further investigated through determinations of stable carbon isotope ratios and measurements of gas exchanges. These investigations suggest that respired CO(2) from substrate oxidation is assimilated by the photosynthetic machinery.

Sterols in recent marine sediments.

Sterolic fractions have been isolated from Recent marine sediments representing two different environments. The fractions were characterized by infrared spectroscopy and thin-layer chromatography. The major sterols in the fractions were identified by gas chromatography and mass spectrometry. The demonstrated survival of these common plant and animal sterols for several thousand years suggests that these molecules will be useful geochemical indicators.

Fatty alcohols (normal and isoprenoid) in sediments.

Normal long-chain alcohols were isolated from Recent marine sediments from several environments. The isoprenoid alcohol dihydrophytol, which is thought to originate from phytol, the side chain of chlorophyll, by hydrogenation in the reducing environment of the sediment, was also present in most of the samples. Both the normal and isoprenoid alcohols were found in the Green River shale (Eocene). Geochemical implications are considered.

Hydrocarbons of blue-green algae: geochemical signfficance.

The hydrocarbon compositions of 11 species of blue-green algae are simple and qualitatively similar. Three marine coccoids contain only monoenoic and dienoic C(19) hydrocarbons. Hydrocarbons of the remaining eight species are C(15) to C(18). Hydrocarbons of higher molecular weight (C(20) or more) were not detected. Blue-green algae do not appear to be the source material for the longchain (greater than 20 carbons) hydrocarbons found in ancient sediments.

Fatty acids in eleven species of blue-green algae: geochemical significance.

Analyses of the total lipids of 11 species of blue-green algae showed a simple but qualitatively variable fatty acid composition. The species can be grouped in three categories on the basis of their oleic, linoleic, and linolenic acid content. One species was unusual in that the ten-carbon acid accounts for one-half of its total fatty acid. Branched chain acids are absent in the algae, but are major components of marine bacteria. The geochemical significance of the data is discussed.

Branched-chain Fatty acids in sediments.

Branched-chain (iso and anteiso) fatty acids were isolated from marine sediments from several environments. The relatively high ratio of branched-chain to straight-chain fatty acids for the even-numbered carbon molecules suggests a bacterial origin for the branched-chain isomers. The branched-chain fatty acids are present in the Green River shale. Possible geochemical implications are suggested.