Showing papers on "Energy source published in 1996"
Patent•
16 Jan 1996TL;DR: An electrosurgical instrument is provided for cauterization and/or welding of tissue of varying impedances, thicknesses and vascularity especially in the performance of endoscopic procedures as mentioned in this paper.
Abstract: An electrosurgical instrument is provided for cauterization and/or welding of tissue of varying impedances, thicknesses and vascularity especially in the performance of endoscopic procedures. The instrument compresses the tissue between an electrode associated with a first pole of a bipolar energy source located on one interfacing surface off a first element, and a second interfacing surface of a second element. The first and second elements are used to engage and compress tissue between the first and second interfacing surfaces. A second electrode associated with a second pole is located one of the two interfacing surfaces. The first electrode is either recessed into the first tissue contacting surface and/or offset from the second electrode on the same or opposing surfaces. A preferred application of the invention is in a cutting instrument wherein a hemostatic line is formed along a cut line using RF energy.
1,082 citations
TL;DR: The terminal heme/copper oxidases in respiratory electron-transfer chains illustrate a number of the thermodynamic and structural principles that have driven the development of respiration.
Abstract: Spatially well-organized electron-transfer reactions in a series of membrane-bound redox proteins form the basis for energy conservation in both photosynthesis and respiration. The membrane-bound nature of the electron-transfer processes is critical, as the free energy made available in exergonic redox chemistry is used to generate transmembrane proton concentration and electrostatic potential gradients. These gradients are subsequently used to drive ATP formation, which provides the immediate energy source for constructive cellular processes. The terminal heme/copper oxidases in respiratory electron-transfer chains illustrate a number of the thermodynamic and structural principles that have driven the development of respiration. This class of enzyme reduces dioxygen to water, thus clearing the respiratory system of low-energy electrons so that sustained electron transfer and free-energy transduction can occur. By using dioxygen as the oxidizing substrate, free-energy production per electron through the chain is substantial, owing to the high reduction potential of O{sub 2} (0.815 V at pH 7). 122 refs.
1,057 citations
Patent•
18 Jan 1996
TL;DR: An electrosurgical device for medical treatment of tissue at a treatment site through a body opening is described in this paper. But it does not specify a method for using the device and it is not shown how to attach it to an energy source.
Abstract: An electrosurgical device for medical treatment of tissue at a treatment site through a body opening. The device includes a sheath having proximal and distal extremities and having a passageway extending from the proximal extremity to the distal extremity. A guide tube is slidably mounted in the passageway of the sheath and has proximal and distal extremities and a lumen extending from the proximal extremity to the distal extremity. A needle electrode is slidably mounted in the lumen of the guide tube and has proximal and distal extremities. Insulation is coaxially disposed on the needle electrode. A handle adapted to be gripped by the human hand is provided and the proximal extremity of the guide tube is mounted on the handle. An assembly is carried by the handle for bending the distal extremity of the guide tube at an angle with respect to the longitudinal axis. The needle electrode is adapted to be coupled to an energy source. A single actuation element is carried by the handle and coupled to the needle electrode and the insulation. The actuation element is movable in a single stroke from a first position in which the needle electrode and the insulation are disposed within the guide tube and a second position in which the needle electrode and the insulation are disposed in the tissue at the treatment site. A method for using the device is provided.
753 citations
TL;DR: The development of Jatropha curcas L. as a possible energy crop in Nicaragua is discussed in this article, where a technical process for the processing of the seeds and the production of the methyl esters from the seed oil is described.
526 citations
TL;DR: It is demonstrated that increased muscle TG stores are associated with decreased insulin-stimulated glycogen synthase activity, which may underlie a major part of the insulin resistance in normal subjects, as well as type II diabetics.
Abstract: Intracellular triglyceride (TG) is an important energy source for skeletal muscle. However, recent evidence suggests that if muscle contains abnormally high TG stores its sensitivity to insulin may be reduced, and this could predispose to type II diabetes. To test this hypothesis, we measured muscle lipid content in 27 women aged 47 to 55 years (mean, 52) and related it to their glucose tolerance, insulin resistance, and muscle insulin sensitivity as measured by insulin activation of glycogen synthase, an insulin-regulated enzyme that is rate-limiting for insulin action in muscle. Both muscle TG content and intracellular lipid determined by Oil red O staining of muscle fibers were negatively associated with glycogen synthase activation ( r = .43, P = .03 and r = −.47, P = .02, respectively). In addition, intracellular lipid correlated with features of the insulin resistance syndrome, including an increased waist to hip ratio ( r = .47, P = .01) and fasting nonesterified fatty acids ([NEFA] r = .44, P = .04). These data demonstrate that increased muscle TG stores are associated with decreased insulin-stimulated glycogen synthase activity. Intracellular fat may underlie a major part of the insulin resistance in normal subjects, as well as type II diabetics.
414 citations
TL;DR: Analysis of stable carbon and nitrogen isotopes showed that this chemoautotrophic production is the food base for 48 species of cave-adapted terrestrial and aquatic invertebrates, 33 of which are endemic to this ecosystem.
Abstract: Microbial mats discovered in a ground-water ecosystem in southern Romania contain chemoautotrophic bacteria that fix inorganic carbon, using hydrogen sulfide as an energy source. Analysis of stable carbon and nitrogen isotopes showed that this chemoautotrophic production is the food base for 48 species of cave-adapted terrestrial and aquatic invertebrates, 33 of which are endemic to this ecosystem. This is the only cave ecosystem known to be supported by in situ autotrophic production, and it contains the only terrestrial community known to be chemoautotrophically based.
361 citations
TL;DR: The lower-range values of the theoretically calculated yields of glycerol were in good agreement with the experimental yields, which may indicate that the regulation of metabolism succeeds in the most efficient balancing of the redox potential.
Abstract: To prevent the loss of raw material in ethanol production by anaerobic yeast cultures, glycerol formation has to be reduced. In theory, this may be done by providing the yeast with amino acids, since the de novo cell synthesis of amino acids from glucose and ammonia gives rise to a surplus of NADH, which has to be reoxidized by the formation of glycerol. An industrial strain of Saccharomyces cerevisiae was cultivated in batch cultures with different nitrogen sources, i.e., ammonium salt, glutamic acid, and a mixture of amino acids, with 20 g of glucose per liter as the carbon and energy source. The effects of the nitrogen source on metabolite formation, growth, and cell composition were measured. The glycerol yields obtained with glutamic acid (0.17 mol/mol of glucose) or with the mixture of amino acids (0.10 mol/mol) as a nitrogen source were clearly lower than those for ammonium-grown cultures (0.21 mol/mol). In addition, the ethanol yield increased for growth on both glutamic acid (by 9%) and the mixture of amino acids (by 14%). Glutamic acid has a large influence on the formation of products; the production of, for example, alpha-ketoglutaric acid, succinic acid, and acetic acid, increased compared with their production with the other nitrogen sources. Cultures grown on amino acids have a higher specific growth rate (0.52 h-1) than cultures of both ammonium-grown (0.45 h-1) and glutamic acid-grown (0.33 h-1) cells. Although the product yields differed, similar compositions of the cells were attained. The NADH produced in the amino acid, RNA, and extracellular metabolite syntheses was calculated together with the corresponding glycerol formation. The lower-range values of the theoretically calculated yields of glycerol were in good agreement with the experimental yields, which may indicate that the regulation of metabolism succeeds in the most efficient balancing of the redox potential.
360 citations
TL;DR: The energy problems of the developing world are both serious and widespread and lack of access to sufficient and sustainable supplies of energy affects as much as 90% of the population of many developing countries as mentioned in this paper.
Abstract: ▪ Abstract The energy problems of the developing world are both serious and widespread. Lack of access to sufficient and sustainable supplies of energy affects as much as 90% of the population of many developing countries. Some 2 billion people are without electricity; a similar number remain dependent on fuels such as animal dung, crop residues, wood, and charcoal to cook their daily meals. Without efficient, clean energy, people are undermined in their efforts to engage effectively in productive activities or to improve their quality of life. Developing countries are facing two crucial—and related—problems in the energy sector. The first is the widespread inefficient production and use of traditional energy sources, such as fuelwood and agricultural residues, which pose economic, environmental, and health threats. The second is the highly uneven distribution and use of modern energy sources, such as electricity, petroleum products, and liquefied or compressed natural gas, which pose important issues of ...
351 citations
TL;DR: In this article, the authors analyzed the change in energy efficiency in a transition from fossil-fuel-based to biomass-based systems and found that future increases in yield and technological development will almost double net energy yields for dedicated energy crops within the next two decades.
Abstract: Energy efficiency in the production and transportation of different kinds of biomass in Sweden has been analysed, as well as the change in energy efficiency in a transition from fossil-fuel-based to biomass-based systems. Net energy yields under current production conditions were found to be highest for short-rotation forest (Salix) and sugar beet (about 160 to 170 GJ ha-1 year-1), followed by ley crops (110 to 140 GJ ha-1 year-1), and rape, wheat, and potatoes (50 to 90 GJ ha-1 year-1). The energy input per unit biomass produced is lowest for straw, logging residues and Salix, equal to 4 to 5% of the energy output. Corresponding figures for perennial ley crops are 7 to 10% and for annual crops 15 to 35%. Salix chips can be transported by truck about 250 km before the transportation energ is equal to the production energy. Corresponding distances for tractor, train and boat (coastal shipping) are about 100 km, 500 km and 1000 km, respectively. It is estimated that future increases in yield and technological development will almost double net energy yields for dedicated energy crops within the next two decades. A transition from a fossil-fuel-based energy system to a CO2-neutral biomass-based system around the year 2015 is estimated to increase the energy input in biomass production and transportation by about 30 to 45%, resulting in a decreased net energy output of about 4%. (Less)
284 citations
Book•
19 Mar 1996
TL;DR: In this paper, the authors present a Prologue on Energy and Sustainability, which includes the following: 1. Energy Flows and Supplies. 2. Human Energy Consumption.
Abstract: I. ENERGY. 1. Energy Flows and Supplies. Prologue on Energy and Sustainability. Natural Energy Flows. Human Energy Consumption. Human Energy Sources. 2. Fossil Fuels. Carbon Cycle. Origins of Fossil Fuels. Fuel Energy. Petroleum. Gas. Coal. Decarbonization. 3. Nuclear Energy. Nuclei, Isotopes, and Radioactivity. Naturally Occurring Radioisotopes. Decay Chains: The Radon Problem. Radioactivity: Biological Effects of Ionizing Radiation. Radiation Exposure. Fission. Hazards of Nuclear Power. Is Nuclear power Part of the Future? Fusion. 4. Renewable Energy. Solar Heating. Solar Thermal Electricity. Photovoltaic Electricity. Biomass. Hydroelectricity. Wind Power. Ocean Energy. Geothermal Energy. 5. Energy Utilization. Heat Engine Efficiencies. Fuel Cells. Space Heating, Cogeneration. Electricity Storage: The Hydrogen Economy. The Materials Connection. Systems Efficiency. Energy and Society. II. ATMOSPHERE. 6. Climate. Radiation Balance. Albedo: Particles and Clouds. Greenhouse Effect. Climate Modeling. International Agreements on Greenhouse Gases. 7. Oxygen Chemistry. Nitrogen Oxides: Free Energy. Nitrogen Oxides: Kinetics. Free Radical Chain Reactions. 8. Stratospheric Ozone. Atmospheric Structure. Ultraviolet Protection by Ozone. Ozone Chemistry. Catalytic Destruction of Ozone. Polar Ozone Destruction. Ozone Projections. CFC Substitutes. 9. Air Pollution. Pollutants and Their Effects. Photochemical Smog. Emission Control. Reformulated Gasoline: Oxygenates. III. HYDROSPHERE/LITHOSPHERE. 10. Water Resources. Global Perspective. Irrigation. Groundwater. U.S. Water Resources. The Oceans. Water as Solvent and as a Biological Medium. 11. From Clouds to Runoff: Water as Solvent. Unique Properties of Water. Acids, Bases, and Salts. Conjugate Acids and Bases Buffers. Water in the Atmosphere: Acid Rain. 12. Water and the Lithosphere. Earth as Acid-Base Reactor. Organic and Inorganic Carbon Cycles. Weathering and Solubilization Mechanisms. Effects of Acidification. 13. Oxygen and Life. Redox Reactions and Energy. Aerobic Earth. Water as Ecological Medium. 14. Water Pollution and Water Treatment. Water Use and Water Quality: Point and Nonpoint Sources of Pollution. Regulation of Water Quality. Water and Sewage Treatment. Health Hazards. IV. BIOSPHERE. 15. Nitrogen and Food Production. Nitrogen Cycle. Agriculture. Nutrition. 16. Pest Control. Insecticides. Herbicides. Genetically Modified Organisms (GMOs). 17. Toxic Chemicals. Acute and Chronic Toxicity. Cancer. Hormonal Effects. Persistent Organic Pollutants: dioxins and PCBs. Toxic Metals. Appendix: Organic Structure. Hydrocarbons: Alkanes. Branched Chains Isomers. Rings. Unsaturated Hydrocarbons. Molecular Shape. Carbon Framework Representations. Aromatic Compounds. Hetero-Atoms Functional Groups. Index.
236 citations
Patent•
15 Aug 1996
TL;DR: In this article, a multiple probe device with at least one lumen, a longitudinal axis and an ablative surface area of length L 1 is described, where L 2 is at least equal to 1/3 L 1.
Abstract: An ablation treatment apparatus has a multiple probe device. The multiple probe device includes a primary electrode/probe/antenna with at least one lumen, a longitudinal axis and an ablative surface area of length L1. The multiple probe device also includes a secondary electrode/probe/antenna that is positioned in a lumen of the primary probe as this last is introduced through tissue. A secondary electrode/probe/antenna distal end is slidingly deployed at a selected tissue site from the primary electrode/probe/antenna lumen in a lateral direction relative to the longitudinal axis. A sensor is at least partially positioned at an exterior of the secondary electrode/probe/antenna distal end at a distance L2 from the primary electrode/probe/antenna along the secondary electrode/probe/antenna distal end. L2 is at least equal to 1/3 L1. An energy source is coupled to the primary electrode/probe/antenna.
TL;DR: In light of numerous proposals to improve microbial cellulose digestion in ruminants, it is instructive to examine the characteristics of these species that contribute to their superior cellulolytic capabilities and to identify the factors that prevent them from digesting cellulose even more rapidly.
01 Sep 1996
TL;DR: In this article, a probabilistic model of a wind farm to be used in reliability studies is presented, which considers the stochastic nature of wind, the failure and repair processes of the wind turbines under different wind regimes, and the output characteristics of wind turbine in detail.
Abstract: Wind generation is one of the most successful sources of renewable energy for the production of electrical energy. As the number of installations connected into existing networks grows rapidly worldwide there is a need to study the reliability of these energy sources and assess their effects on the system. However, the technical characteristics of wind generation make existing conventional generation models not directly applicable. A new probabilistic model of a wind farm to be used in reliability studies is presented. This model considers the stochastic nature of wind, the failure and repair processes of the wind turbines under different wind regimes, and the output characteristics of the wind turbine in detail. Spatial wind speed correlation and waking effects can also be considered. The model can be used with one or several types of wind turbines. Analytical techniques are used. A practical application of the models is also included.
TL;DR: The results suggest that in human erythrocytes ascorbate regeneration from dehydroascorbate is largely GSH dependent, and that it occurs through either enzymatic or nonenzymatic reactions not involving the monoascorbyl free radical.
TL;DR: In the photosynthetic bacterium Rhodospirillum rubrum, the presence of carbon monoxide (CO) induces expression of several proteins, such as CODH and CO-tolerant hydrogenase as mentioned in this paper.
Abstract: In the photosynthetic bacterium Rhodospirillum rubrum, the presence of carbon monoxide (CO) induces expression of several proteins. These include carbon monoxide dehydrogenase (CODH) and a CO-tolerant hydrogenase. Together these enzymes catalyze the following conversion: CO + H2O --> CO2 + H2. This system enables R. rubrum to grow in the dark on CO as the sole energy source. Expression of this system has been shown previously to be regulated at the transcriptional level by CO. We have now identified the remainder of the CO-regulated genes encoded in a contiguous region of the R. rubrum genome. These genes, cooMKLXU, apparently encode proteins related to the function of the CO-induced hydrogenase. As seen before with the gene for the large subunit of the CO-induced hydrogenase (cooH), most of the proteins predicted by these additional genes show significant sequence similarity to subunits of Escherichia coli hydrogenase 3. In addition, all of the newly identified coo gene products show similarity to subunits of NADH-quinone oxidoreductase (energy-conserving NADH dehydrogenase I) from various eukaryotic and prokaryotic organisms. We have found that dicyclohexylcarbodiimide, an inhibitor of mitochondrial NADH dehydrogenase I (also called complex I), inhibits the CO-induced hydrogenase as well. We also show that expression of the cooMKLXUH operon is regulated by CO and the transcriptional activator CooA in a manner similar to that of the cooFSCTJ operon that encodes the subunits of CODH and related proteins.
TL;DR: It is proved that the short duration of protein synthesis in a conventional cell‐free protein synthesis system of batch configuration can be attributed both to depletion of energy sources and deactivation of S30 extract by small‐molecule byproducts produced during the protein synthesis.
Abstract: This report describes a novel and simple cell-free protein synthesis system. In this paper, we prove that the short duration of protein synthesis in a conventional cell-free protein synthesis system of batch configuration can be attributed both to depletion of energy sources and deactivation of S30 extract by small-molecule byproducts produced during the protein synthesis. The reaction period of cell-free protein synthesis system could be extended through an operation of a continuous-flow cell-free protein synthesis system, which was originally developed by Spirin. However, inspite of the greatly extended reaction period, the final amount of cell-free produced protein was not significantlly larger than that can be obtained from a batch system due to the reduced rate of protein synthesis. It was supposed that the reduced rate of protein synthesis in the continuous-flow system was attributed to leakage of translational components through the ultrafiltration membrane during the operation of the continuous-flow system. To solve such a problem of the continuous-flow system, we have developed and operated a novel reactor for cell-free protein synthesis. By use of this system, protein synthesis occurred for at least 14 h, yielding 1.2 mg/mL CAT protein. The present system is superior to the continuous-flow system as well as the conventional batch system in that it enables extremely high productivity without using any complex and hard-to-handle apparatus. As far as we know, the yield of cell-free protein synthesis given above is the best of the results reported to date.
Patent•
22 Apr 1996
TL;DR: In this paper, a shape-memory with an activated shape and a quiescent shape is used to encourage the shape of a selected portion of the body to open the pharynx.
Abstract: An apparatus and method for reversibly modifying the shape of a selected portion of the body such as the pharynx, to produce a desired result, for example, to overcome obstructive sleep apnea by urging open the pharynx. The apparatus includes a preconfigured structure having a shape-memory with an activated shape and a quiescent shape. The preconfigured structure is shaped to conform to the selected portion of the body. The shape-memory is responsive to activation energy and urges the preconfigured structure from the quiescent shape to the activated shape. Furthermore, the activated shape of the preconfigured structure exerts a force on the selected portion, thereby modifying the shape of the selected portion. The preconfigured structure can be attached to an exterior surface of, or can be implanted within the body proximate to, the selected portion of the body. The apparatus can include an energy source coupled to the preconfigured structure for providing the activation energy, responsive to a predetermined stimulus and can be attached external to, or implanted within, the body. The invention also provides a method for reversibly modifying the shape of a selected portion of a body. The method includes attaching a preconfigured shape-memory structure to the selected portion of the body; and applying the activation energy to the preconfigured structure with an energy source, thereby the preconfigured shape-memory structure from the quiescent shape to the activated shape.
TL;DR: Results of substrate uptake suggested that the sludge preferred to utilize glucose instead of cellular glycogen as an energy source during acids uptake, suggesting that they could assimilate or possibly scavenge most of the dissolved substrate of the waste water and dominate in the deteriorated biological phosphorus removal processes.
TL;DR: The Biomass Resource Assessment Version One (BRAVO) system is a computer-based decision support system to assist the Tennessee Valley Authority (TVA) in estimating the costs for supplying wood fuel to any one of its 12 coal-fired power plants as mentioned in this paper.
Abstract: The Biomass Resource Assessment Version One (BRAVO) system is a computer-based decision support system to assist the Tennessee Valley Authority (TVA) in estimating the costs for supplying wood fuel to any one of its 12 coal-fired power plants. The task of estimating wood fuel costs is particularly challenging due to the fact that wood fuel is not an established commodity. In contrast to conventional fossil fuels, geographic proximity to supply is a main determinant in the cost of wood fuel at a power plant. As a consequence, BRAVO is being developed within a Geographic Information System (GIS) platform. The GIS platform allows for the efficient analysis of transportation networks so that accurate estimates of hauling distances and costs can be determined. The system is designed to estimate the total purchase and transportation costs of three types of wood fuel under various levels of demand. This comprehensive system includes information on all possible wood fuel supply points, demand points and product movement costs. With this information, the system can estimate the total cost to supply a particular power plant with a desired quantity of wood fuel and can be used to evaluate “what if?” scenarios related to supply. An analysis of nine TVA plants revealed significant variation in biomass fuel resources within the region. This result suggests that a plant-based approach to biomass resource assessment is crucial to determining the economic feasibility of co-firing.
Patent•
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TL;DR: In this paper, an apparatus and method for sealing an inner wall of a portion of a casing positioned in a well employs an inflatable sleeve having an outer surface and a conformable composite sleeve of curable composition extending around the outer surface.
Abstract: An apparatus and method for sealing an inner wall of a portion of a casing positioned in a well employs an inflatable sleeve having an outer surface and a conformable composite sleeve of curable composition extending around the outer surface of the inflatable sleeve. The inflatable sleeve is inflated to compress the composite sleeve against the surface of the inner casing wall. A local, activatable energy source, positioned downhole to deliver heat to the composite sleeve, is activated to cure the composite sleeve to form a hardened sleeve. The hardened sleeve presses against the inner wall of the casing portion to create a fluid seal. The embodiments shown have a number of preferred features. The local energy source includes an exothermic heat energy source for generating heat energy to cure the composite sleeve. The composite sleeve includes a mixture of resin and a curing agent, and the exothermic heat source includes thermite. The thermite includes a composition having a metal oxide and a reductant. A starter mix is positioned adjacent the exothermic heat energy source, and the starter mix is ignited to start an exothermic reaction in the heat energy source. A conformable layer extends around the composite sleeve, with the layer serving to form a seal between the composite sleeve and the inner wall of the casing portion.
TL;DR: In this paper, the authors test the hypothesis that animal distribution among hydrothermal vents is related to tectonic plate history and find that the predominant migration pathway is most likely to occur along mid-ocean ridges rather than by shortest oceanic routes.
Abstract: ONE remarkable discovery of recent decades is the presence of hundreds of unusual species, including fourteen new families, at hydrothermal vents. These animals, unknown from other habitats, live in extreme chemical and thermal conditions around vents on spreading centres of the mid-ocean ridges and back-arc basins. Chemosynthesis provides an in situ energy source for the thriving vent fauna. This habitat has existed through the Phanerozoic1,2 and probably since the Archaean, thus providing sites for long-term adaptation. We now test the hypothesis that animal distribution among hydrothermal vents is related to tectonic plate history3,4. The predominant migration pathway is most likely to occur along mid-ocean ridges rather than by shortest oceanic routes. Similarity analyses suggest that the distribution patterns of today's vent fauna display the strong imprint of the timing and geometry of ancient plate boundaries. Study of past ridge geometry provides a method to predict relationships among vent communities yet to be discovered.
Patent•
15 May 1996
TL;DR: An electrode assembly for a resectoscope includes, a cutting electrode with a loop distal tip and a coagulation electrode with an external support frame as discussed by the authors, which supplies energy from the energy source to the electrodes.
Abstract: An electrode assembly for a resectoscope includes, a cutting electrode with a loop distal tip and a coagulation electrode with a loop distal tip. A support frame connects the cutting and coagulation electrodes to an energy source which supplies energy from the energy source to the electrodes. The coagulation electrode provides tissue coagulation simultaneously while the cutting electrode cuts tissue. A resectoscope is disclosed which includes the electrode assembly. The resectoscope includes a sheath with a sheath lumen, a working element, and a visualization apparatus.
TL;DR: In this paper, the authors suggest a regional approach to ensure that energy crop production will proceed in an ecologically and economically sustainable way, and suggest that three types of agricultural land be targeted for perennial biomass energy crops: (1) highly erodible land; (2) wetlands presently converted to agricultural uses; and (3) marginal agricultural land in selected regions.
Abstract: Power generation using biomass could provide substantial environmental and socio-economic benefits. Production of the feedstocks to fuel biomass power plants can either add to potential environmental gains or contribute to the environmental problems which the agriculture and forestry industries already face. Likewise, the biomass energy infrastructure can help strengthen agricultural economies or speed the decline of rural communities. The purpose of this paper is to suggest a regional approach to ensure that energy crop production will proceed in an ecologically and economically sustainable way. At this juncture, we have the opportunity to build into the system some ecological and socio-economic values which have not traditionally been considered. If crop species are chosen and sited properly, incorporation of energy crops into our agricultural system could provide extensive wildlife habitat and address soil and water quality concerns, in addition to generating renewable power. We recommend that three types of agricultural land be targeted for perennial biomass energy crops: (1) highly erodible land; (2) wetlands presently converted to agricultural uses; and (3) marginal agricultural land in selected regions. Fitting appropriate species to these lands, biomass crops can be successfully grown on lands not ecologically suited for conventional farming practices, thus providing an environmental benefit in addition to producing an economic return to the land owner.
TL;DR: Results suggest the involvement of specific enzymes for the degradation of each enantiomer in Sphingomonas herbicidovorans MH, as oxygen consumption was strongly dependent on the growth substrate.
Abstract: Sphingomonas herbicidovorans MH (previously designated Flavobacterium sp. strain MH) was able to utilize the chiral herbicide (RS)-2-(4-chloro-2-methylphenoxy)propionic acid (mecoprop) as the sole carbon and energy source. When strain MH was offered racemic mecoprop as the growth substrate, it could degrade both the (R) and the (S) enantiomer to completion, as shown by biomass formation, substrate consumption, and stoichiometric chloride release. However, the (S) enantiomer disappeared much faster from the culture medium than the (R) enantiomer. These results suggest the involvement of specific enzymes for the degradation of each enantiomer. This view was substantiated by the fact that resting cells of strain MH grown on (S)-mecoprop were able to degrade the (S) but not the (R) enantiomer of mecoprop. Accordingly, resting cells of strain MH grown on (R)-mecoprop preferentially metabolized the (R) enantiomer. Nevertheless, such cells could transform (S)-mecoprop at low rates. Oxygen uptake rates with resting cells confirmed the above view, as oxygen consumption was strongly dependent on the growth substrate. Cells grown on (R)-mecoprop showed oxygen uptake rates more than two times higher upon incubation with the (R) than upon incubation with the (S) enantiomer and vice versa.
TL;DR: Although biomass loss could be reduced by lowering the temperature and avoiding mixing of the culture during the night, the loss could not be completely prevented and a cyclic light-autotrophic/dark-heterotrophic culture was investigated as a means of preventing night biomass loss.
TL;DR: A new strictly anaerobic, gram-negative bacterium was isolated from the sediment of a freshwater lake after enrichment with thiosulfate as the energy source and was shown to be related to, but distinct from members of the genus Desulfobulbus on the basis of physiological characteristics and by comparative sequence analysis of its 16S rDNA.
Abstract: A new strictly anaerobic, gram-negative bacterium was isolated from the sediment of a freshwater lake after enrichment with thiosulfate as the energy source The strain, named Bra2 (DSM 7269), is able to grow by disproportionation of thiosulfate or sulfite to sulfate plus sulfide Elemental sulfur is also disproportionated to sulfate and sulfide, but this only supports growth if free sulfide is chemically removed from the culture, eg, by precipitation with amorphous ferric hydroxide Growth is also possible by coupling the reduction of sulfate to sulfide with the oxidation of ethanol, propanol, or butanol to the corresponding fatty acid The cells are rod-shaped, motile, and have genomic DNA with a mol% G+C content of 507 Cytochromes are present, but desulfoviridin is not The new strain was shown to be related to, but distinct from members of the genus Desulfobulbus on the basis of physiological characteristics and by comparative sequence analysis of its 16S rDNA Strain Bra2 is described as the type strain of a new taxon, Desulfocapsa thiozymogenes gen nov, sp nov
TL;DR: The results suggest that the neuroendocrine environment of the small intestine may play a role in the growth of O157:H7 and the production of SLTs.
TL;DR: In this paper, a 1".3 spatial resolution interferometric spectral line survey of the core of the Orion molecular cloud is presented, obtained with the OVRO millimeter array.
Abstract: We present a 1".3 spatial resolution interferometric spectral line survey of the core of the Orion molecular cloud, obtained with the OVRO millimeter array. Covering 4 GHz bandwidth in total, the survey contains ~100 emission lines from 18 chemical species. The spatial distributions of a number of molecules point to source I near the IRc2 complex as the dominant energy source in the region but do not rule out the presence of additional lower luminosity objects. At arcsecond resolution, the offsets between dust emission and various molecular tracers suggest that the spectacular "hot core" emission in the Orion core arises via the heating and ablation of material from the surfaces of very high density clumps located ≳500 AU from source I and traced by the dust emission. We find no evidence for a strong internal heating source within the hot core condensation(s).
TL;DR: Physiological effects of deficiency of pantothenate, a necessary precursor in the synthesis of coenzyme A, were studied using the yeast strain Saccharomyces cerevisiae CBS 8066 using anaerobic batch cultures with glucose as the carbon and energy source.
Abstract: Physiological effects of deficiency of pantothenate, a necessary precursor in the synthesis of coenzyme A, were studied using the yeast strain Saccharomyces cerevisiae CBS 8066. Cells were grown on defined media in anaerobic batch cultures with glucose (50 g/l) as the carbon and energy source. Batch cultures containing more than 60 μg/l pantothenate showed no significant differences with respect to growth rates and product yields. However, with an initial pantothenate concentration of 30 μg/l, the average glucose consumption rate was 50% lower than in rich medium and, at even lower concentrations of pantothenate, the culture did not consume all the glucose in the medium. Furthermore, pantothenate deficiency caused the acetate and pyruvate yields to increase and the biomass yield to decrease, compared to the yields in pantothenate-rich medium. The increased acetate formation could be counteracted by initial addition of acetate to the medium, and thereby the glycerol yield could be decreased. An initial addition of acetate of 1.6 g/l to pantothenate-deficient medium (30 μg/l) caused a 35% decrease in glycerol yield and a 6% increase in ethanol yield. Furthermore, the time required for complete conversion of the glucose decreased by 40%. Acetate addition affected the acetate and glycerol yields in a similar way in pantothenate-rich medium (1000 μg/l) also.
01 Nov 1996
TL;DR: The diet, therefore, may be particularly important for those individuals predisposed to large-bowel cancer and a better understanding of how dietary factors may influence colon cancer risk may lead to dietary intervention.
Abstract: Colo-rectal cancer is a major health problem in industrialized countries and the high incidence has been linked with the diet (Burkitt, 1971) The colonic epithelium is in direct contact with dietary factors present in the lumen and these factors may affect the pattern of growth, differentiation and cell death within the tissue Epidemiological studies suggest that a low-fat, high-fibre diet is protective for colo-rectal cancer (Burkitt, 1971; Howe et al 1992) whereas a diet high in red meat and saturated fat and low in dietary fibre and vegetables is associated with an increased risk for colo-rectal cancer Colon cancers most often develop from premalignant adenomas (sometimes referred to as polyps) which, in turn, are derived from the normal colonic epithelium Sandler et al (1993) conducted an epidemiological study which showed that diets high in fat and low in carbohydrates and fibre not only increased the risk for colo-rectal cancer, but also for the precursor adenomas The diet, therefore, may be particularly important for those individuals predisposed to large-bowel cancer and a better understanding of how dietary factors may influence colon cancer risk may lead to dietary intervention Dietary fibre is composed of non-polysaccharides such as lignin and the NSP, carbohydrates such as cellulose, pectin and gums which are derived from plant cell walls Fibre escapes digestion in the stomach and small intestine, as do oligosaccharides and some resistant starches (Silvester et al 1995) but in the large bowel symbiotic bacteria are able to ferment these carbohydrates, releasing the short-chain fatty acids (butyrate, propionate and acetate) as a by-product of this metabolism There are a number of ways in which fibre could protect against colo-rectal cancer It increases transit rate and bulk, thereby potentially decreasing exposure to carcinogens in the diet It adsorbs carcinogens, modifies intestinal microflora (and may, therefore, alter bile salt and carcinogen metabolism), decreases faecal bile salt excretion and lowers the colonic pH, as well as increasing the concentrations of the short-chain fatty acids in the large bowel (McIntyre et al 1993) The diet is complex, and in epidemiological studies it is difficult to unravel the effects of individual components For example, diets high in animal fat may also contain carcinogens generated during cooking of meat Diets low in fruit and vegetable fibre may be low in vitamins which have antioxidant effects (for review, see Rogers et al 1993) Animal studies have helped in this respect in that diets can be more carefully controlled, but the results are variable because of the types of fibre administered (Levin, 1992) Dietary wheat bran results in higher concentrations of butyrate than either oat bran or guar gum (Kashtan et al 1992; McIntyre et al 1993)