Showing papers on "Energy source published in 1990"

Ribozymes as potential anti-HIV-1 therapeutic agents.

Abstract: Certain RNA molecules, called ribozymes, possess enzymatic, self-cleaving activity. The cleavage reaction is catalytic and no energy source is required. Ribozymes of the "hammerhead" motif were identified in plant RNA pathogens. These ribozymes possess unique secondary (and possibly tertiary) structures critical for their cleavage ability. The present study shows precise cleavage of human immunodeficiency virus type 1 (HIV-1) sequences in a cell-free system by hammerhead ribozymes. In addition to the cell-free studies, human cells stably expressing a hammerhead ribozyme targeted to HIV-1 gag transcripts have been constructed. When these cells were challenged with HIV-1, a substantial reduction in the level of HIV-1 gag RNA relative to that in nonribozyme-expressing cells, was observed. The reduction in gag RNA was reflected in a reduction in antigen p24 levels. These results suggest the feasibility of developing ribozymes as therapeutic agents against human pathogens such as HIV-1.

Spatially-addressable immobilization of anti-ligands on surfaces

Abstract: Methods and compositions are described for immobilizing anti-ligands, such as antibodies or antigens, hormones or hormone receptors, oligonucleotides, and polysaccharides on surfaces of solid substrates for various uses. The methods provide surfaces covered with caged binding members which comprise protecting groups capable of being removed upon application of a suitable energy source. Spatially addressed irradiation of predefined regions on the surface permits immobilization of anti-ligands at the activated regions on the surface. Cycles of irradiation on different regions of the surface and immobilization of different anti-ligands allows formation of an immobilized matrix of anti-ligands at defined sites on the surface. The immobilized matrix of anti-ligands permits simultaneous screenings of a liquid sample for ligands having high affinities for certain anti-ligands of the matrix. A preferred embodiment of the invention involves attaching photoactivatable biotin derivatives to a surface. Photolytic activation of the biotin derivatives forms biotin analogs having strong binding affinity for avidin. Biotinylated anti-ligands can be immobilized on activated regions of the surface previously treated with avidin.

Renewable energy sources

Abstract: Introduction to the report. Introduction and summary. The place of renewable energy as an energy source. Types of renewable energy source. Tidal energy. Wave energy. Wind energy. Small scale hydro- electric energy. Geothermal energy. Ocean thermal energy conversion (OTEC). Solar thermal technologies and photovoltaics. Biofuels. System considerations. Environment. Integration of renewable energy sources in electrical power systems. Economics of renewable energy sources. The Watt Committee on energy Objectives, historical background and current program Member institutions of The Watt Committee on Energy. Watt Committee Reports. Index.

Diet, Physical Activity, and Colorectal Cancer Among Chinese in North America and China

Abstract: In a population-based case-control study of colorectal cancer among Chinese men and women in western North America and the People's Republic of China, a common protocol was used to assess past life-style characteristics of 905 cases diagnosed during 1981-1986 and 2,488 controls. Risks for cancers of both the colon and rectum increased with increased food energy from fat, protein, carbohydrate, and all energy sources combined, for both sexes and on both continents. Yet, in multivariate analysis, colorectal cancer risk was significantly associated only with saturated fat; no relationships were seen with other dietary sources of energy. Colon cancer risk was elevated among men employed in sedentary occupations. On both continents and in both sexes, risks for cancers of both the colon and rectum increased with increasing time spent sitting. Further, the association between colorectal cancer risk and saturated fat was stronger among the sedentary than among the active. Risk among sedentary Chinese Americans of either sex increased more than fourfold from the lowest to the highest category of saturated fat intake. Among migrants to North America, risk increased with increasing years lived in North America. These observations suggest (a) that colorectal cancer risk increases with duration of exposure to a sedentary life-style and a diet rich in saturated fat; (b) that higher incidence among Chinese-American men relative to women is due to longer duration of these habits among men, who have lived longer in North America; and (c) that higher risk among Chinese Americans of both sexes relative to risk among the general population in China is due to differences in such habits. Attributable risk calculations suggest that, if these associations are causal, saturated fat intakes exceeding 10 g/day, particularly in combination with physical inactivity, could account for 60% of colorectal cancer incidence among Chinese-American men and 40% among Chinese-American women.

Power sources for downhole electrical heating

Abstract: Electrical power sources and systems for heating in or adjacent to an oil well or other mineral well, or for heating other earth media, each comprising an A.C. heating generator that generates an A.C. heating current at a selected heating frequency substantially different from the conventional 50/60 Hz frequency used by power companies; the heating generator may comprise an A.C. to D.C. converter for developing an intermediate D.C. output of predetermined amplitude from a conventional 50/60 Hz A.C. input, and a solid state switching circuit for repetitively sampling the D.C. output of the converter at the selected heating frequency, usually in a range of 0.01 Hz (or even lower) up to about 35 Hz. A heating rate control varies the energy content and the frequency of the A.C. output to suit well requirements. Each power source or system includes output connections for connecting the output of the heating generator to a normally inaccessible main heating electrode, usually located downhole in a well, and to a return electrode; most have the capability of including a very small controllable D.C. component in the output.

Isolation and characterization of a fluoranthene-utilizing strain of Pseudomonas paucimobilis.

Abstract: A soil bacterium capable of utilizing fluoranthene as the sole source of carbon and energy for growth was purified from a seven-member bacterial community previously isolated from a creosote waste site for its ability to degrade polycyclic aromatic hydrocarbons. By standard bacteriological methods, this bacterium was characterized taxonomically as a strain of Pseudomonas paucimobilis and was designated strain EPA505. Utilization of fluoranthene by strain EPA 505 was demonstrated by increase in bacterial biomass, decrease in aqueous fluoranthene concentration, and transient formation of transformation products in liquid cultures where fluoranthene was supplied as the sole carbon source. Resting cells grown in complex medium showed activity toward anthraquinone, benzo[b]fluorene, biphenyl, chrysene, and pyrene as demonstrated by the disappearance of parent compounds or changes in their UV absorption spectra. Fluoranthene-grown resting cells were active against these compound as well as 2,3-dimethylnaphthalene, anthracene, fluoranthene, fluorene, naphthalene, and phenanthrene. These studies demonstrate that organic compounds not previously reported to serve as growth substrates can be utilized by axenic cultures of microorganisms. Such organisms may possess novel degradative systems that are active toward other compounds whose biological degradation has been limited because of inherent structural considerations or because of low aqueous solubility.

Bacterial production on humic and nonhumic components of dissolved organic carbon

Abstract: Dissolved humic substances make up - 50% or more of the dissolved organic carbon (DOC) in freshwater ecosystems, yet their trophodynamic roles remain unresolved. We separated DOC from two freshwater environments, a lake and a blackwater marsh, into two fractions, humic DOC and nonhumic DOC, using an XAD-8 resin to selectively adsorb the humic substances. Results of microcosm studies revealed that the humic fraction of DOC was used by natural bacterial assemblages from the lake and marsh as a C and energy source, as indicated both by increases in bacterial biovolume and rates of bacterial incorporation of [3H]thymidine. Humic substances supported fourfold less bacterial secondary production per unit of initial C, however, than did nonhumic substances from the same environment. Bacterial utilization of humic compounds accounted for a significant fraction of the total bacterial production on DOC, measured as increases in bacterial biovolume; humic substances supported an average of 22% of total growth on DOC from the lake and 53% of the total growth on DOC from the marsh. The relative bioavailability of both the humic and nonhumic fractions of DOC differed between the lake and blackwater marsh, with less bacterial production per unit of initial C occurring on marsh-derived dissolved compounds. In aquatic ecosystems, turnover of dissolved organic carbon (DOC) is almost exclusively the domain of bacteria as a result of their high numbers, large surface-to-volume ratios, and transport systems efficient at low substrate concentrations. Studies of bacterial utilization of DOC have indicated the existence of two distinct pools of dissolved compounds, one labile and one refractory, in most aquatic systems (Ogura 1975). Although the labile pool generally accounts for < 20% of the total DOC (Ogura 1975; Allen 1976), it turns over rapidly, on the order of hours to days, and is thought to support the bulk of DOC-based bacterial secondary production (Wright and Hobbie 1966; Allen 1976). The refractory pool is larger but turns over more slowly, on the order of weeks to months (Geller 1986) and therefore may be relatively unimportant as a substrate for bacterial growth. Neither of these two fractions of the DOC pool has been well characterized with respect to

Assembly and secretion of hepatic very-low-density lipoprotein.

Abstract: In contrast to water-soluble fuels such as glucose or ketone bodies, the use of lipids as an energy source for tissues has required the development of complex structures for their transport through the aqueous plasma. In the case of endogenously synthesized triacylglycerol this is achieved by the assembly and secretion of hepatic VLDL which provides the necessary stability in an aqueous medium. An essential component of this assembly process is apo B. Dietary changes which require an increase in hepatic VLDL secretion appear to be accompanied by increases in the availability of functional apo B. Interesting questions relate to: (a) the intracellular site(s) of triacylglycerol association with apo B, and (b) the mechanism(s) by which the availability of functional apo B at this site responds to metabolic and hormonal signals which reflect dietary status and, thus, the need to secrete triacylglycerol. As regards the latter, although in some cases changes in apo B synthesis occur in response to VLDL secretion hepatic apo B mRNA levels appear to be quite stable in vitro. Intracellular switching of apo B between the secretory and degradative pathways may be important in controlling VLDL assembly and post-translational modifications of the apoprotein may also play a role by influencing its ability to bind to triacylglycerol. Transport is not the only problem associated with the utilization of a concentrated energy source such as triacylglycerol and the complex problems of waste product disposal and recycling have to be dealt with. In the case of triacylglycerol, potentially toxic waste products include atherogenic remnants and LDL. The overall problem, then, in the long-term, involves the development of a ‘safe’ means of utilizing triacylglycerol and this requirement accounts for much of the complexity of plasma lipoprotein metabolism. In this area, the rat could teach the human a few tricks. One of these appears to be the utilization of hepatic apo B48 rather than apo B100 for VLDL assembly in response to increases in the extrahepatic utilization of hepatically synthesized triacylglycerol. Under these conditions, the remnants of hepatic triacylglycerol utilization by peripheral tissues are cleared from the plasma much more readily via a process which seems to involve the cycling of more triacylglycerol back to the liver than that which occurs in humans. The means by which this is achieved, though, are obscure and may involve a chylomicron remnant receptor, the nature of which, itself, remains controversial.(ABSTRACT TRUNCATED AT 400 WORDS)

Remote Sensing of Biomass Burning in the Tropics

Abstract: Biomass burning in the tropics, a large source of trace gases, has expanded drastically in the last decade due to increase in the controlled and uncontrolled deforestation in South America (Setzer et al. 1988; Malingreau and Tucker 1988), and due to an increase in the area of cultivated land with the expansion of population in Africa and South America (Seiler and Crutzen 1980; Houghton et al. 1987). In the burning process trace gases and particulates are emitted to the atmosphere, and the ability of the earth to fix CO2 is substantially reduced (17% of the primary productivity occurs in the humid tropical forests — Atjay et al. 1979; Mooney et al. 1987), and as a result has a strong contribution to the anticipated climate change (Houghton and Woodwell 1989).

Apparatus and method for analyzing the composition of formation fluids

Abstract: A borehole apparatus for analyzing the composition of a formation fluid is disclosed and generally comprises a testing chamber, a means for directing a sample of fluid into the chamber, a light source which emits at least near infrared rays, a spectral detector, a data base means, and a processing means. The light source is preferably an incandescent lamp and the testing chamber includes a window which is substantially optically transparent to at least one near infrared light, and preferably also the near ultraviolet and visible light of the source. The light source is directed at least partly towards the window in the chamber either via collimation or fiber optics. The spectral detector means is preferably a spectrometer which detects and measures the spectra of the light which has been transmitted through and the light which is backscattered by the fluid sample. The preferred data base means stores the spectra at different pressures and temperatures of water, gas, and a plurality of oils. A determination of the composition of the fluid sample is made by the processing means by obtaining the spectrum of the source, and at least one of the transmitted light or backscattered light spectra, and by fitting the plurality of spectra in the data base to the obtained spectral information. A determination of a transition of the obtained fluid samples from mud filtrate to formation fluids is made by monitoring the visible light and/or near ultraviolet spectrum for changes in large molecule components.

Handbook of Energy for World Agriculture

Abstract: Commercial and non-commercial energy. Energy for subsistence and development. Human energy capacity. Supplemental energy needs. Energy balance. World energy outlook. Economic considerations. Environmental considerations. Solutions to difficult problems. Energy use. Agriculture's share of commercial energy. Commercial energy use for agricultural inputs. Commercial energy use and cereal output. Commercial energy for fertilizer production and use. Commercial energy for farm machinery manufacture and use. Energy from human labour. Energy from draught animals. Commercial energy for pump irrigation equipment manufacture and operation. Commercial energy for pesticide production and application. Energy flow. Energy surveys and analyses. Regional and national examples. Small-scale hydroelectric power plants. The need for systems approach. Energy management. Germ plasm and its impact on energy use. Fertilizer and biological nitrogen fixation. Pest control. Irrigation. Mechanization of agricultural production. Energy management in the post-harvest system. Food processing. Energy and the food consumption system. Efficient energy management in agricultural is food business. Energy from biomass. Photosynthesis. Wood for fuel. Sources and availability of biomass feedstocks. Freshwater and saltwater plants. Classification of biomass fuels. Energy profiles. Biogas. Hydrogen. Ethanol. Methanol. Vegetable oil. Biomass feedstock. Solid fuels. Solar energy. Fundamentals of solar energy. Collection and storage. Agricultural applications. Future potential of solar energy. Wind energy. Fundamentals of wind power. Wind energy conversion systems. Wind system applications. Wind characteristics. Feasibility studies. Economics. Hydropower. Fundamentals of hydropower. Hydropower potential. Classification of hydropower plants. Reasons to consider small hydropower stations. Planning a hydropower project. The hydroelectric power system. Cost of a small hydroelectric plant. Small hydropower stations versus other alternative sources. Examples of hydropower and uses. Observations on the status of hydropower. Alternatives. Energy options. A framework for policy assessment and formulation. Increasing the energy supply. Decreasing energy demand through efficient management. Policy implications. Research needs. Technology assessment. The Indian Energy Center: a model for developing countries. Appendices: sources of further information conversion of units.

Soft tissue cutting aspiration device and method

Abstract: A laser soft tissue aspiration device comprises an aspiration cannula housing a laser energy transmitting means for conducting laser energy to the site within a patient's body for aspiration of soft tissue. The cannula is provided with an aspiration inlet port adjacent the cannula distal end. The proximal end of the cannula is provided with fluid flow connection to an aspiration source. A laser guide tube is additionally provided housing the laser energy transmitting means extending longitudinally within the cannula lumen from a laser energy source at the cannula proximal end and terminating at a point immediately prior to the aspiration inlet port. The tube also provides a conduit for transmitting cooling and cleaning fluid flow for the laser energy transmitting means. A surgical method of aspirating soft tissue from a patient in vivo using this device is also provided transmitting means. Separated soft tissue and fluid is aspirated through the aspiration inlet port and the cannula by means of an aspiration source at the proximal end of the cannula.

CO2 Emission Limits: An Economic Cost Analysis for the USA

Abstract: GNP growth , elasticity of price induced substitution between capital-labour and energy, and the rate of autonomous energy efficiency improvements) which are crucial to the debate over energy and environmental futures. The paper discusses various energy sources which are either presently in use or will possibly be in use in the future, and analyzes their impact on cost-benefit analyses . Finally, the paper analyzes the results of carbon constraints and suggests that there is need for more research and development on the subject .

Patterns of Nutrient and Energy Expenditure in Female Common Eiders Nesting in the High Arctic

Abstract: -In 1982 we studied weight loss, changes in body composition, and energy expenditure in breeding female Common Eiders (Somateria mollissima borealis) in Svalbard, Norway. Feeding ceased during laying and incubation. From prelaying to hatching, total weight declined by 46.4%, lipid by 81.4%, and protein by 36.8%. Daily energy expenditure during laying was 2,528 kJ, 5.2 times greater than during incubation. Rate of lipid expenditure during laying was 3.3 times greater than during incubation, and rate of protein expenditure was 8.8 times greater. Of the birds' total prelaying energy, 33.8% was expended during laying, 34.6% during incubation, and 31.6% remained at hatching. An estimated 31.6% of the energy expended during laying was invested in eggs. Sixteenand 18-carbon fatty acids dominated in lipid of the fattest and leanest birds. The major nutrient and energy donors during breeding were 16:0 and 18:1 fatty acids. Svalbard eider eggs weighed ca. 17.5% less and were incubated ca. 1.5 days shorter than eggs from the species' most southerly range limit. This apparent adaptation to arctic existence gave an estimated energy savings of 6.5% during breeding. Received 27 September 1989, accepted 4 April 1990. DURING reproduction, female waterfowl require substantial nutrients, mainly lipids and protein, both for egg synthesis and as an energy source during laying and incubation. The pattern of nutrient acquisition for and allocation to reproduction differs among various waterfowl species. Some, like the Ruddy Duck (Oxyura jamaicensis), depend almost exclusively on dietary intake throughout breeding (Tome 1984). Ring-necked Ducks (Aythya collaris; Hohman 1986) and Mallards (Anas platyrhynchos; Krapu 1981) obtain most of the protein required for egg production from the diet, while endogenous lipid reserves supply much of the fat needed for egg production and the energy for incubation. Most Arctic-nesting geese, however, feed sparsely during laying and incubation, and draw heavily on endogenous reserves stored before arrival on the breeding grounds (Ryder 1970, Ankney 1977, Ankney and MacInnes 1978, Raveling 1979). Female Common Eiders (Somateria mollissima borealis) (hereafter, Eiders) feed heavily near nesting islands during the 4-6 weeks before laying, and increase body weight by approximately 20% above winter levels (Gorman and 3Present address: Sofiesgt. 74,0454 Oslo 4, Norway. Milne 1971). They then fast completely during incubation (Cooch 1965: 30, Gorman and Milne 1971, Milne 1976, Korschgen 1977) and apparently during laying as well (Korschgen 1977); the nutrients and energy required for both producing and incubating a clutch of eggs are drawn entirely from endogenous reserves. The Eider represents an extreme case of seasonal negative energy and nutrient balance in breeding birds. Milne (1976) and Korschgen (1977) investigated changes in the body weight and composition of Eiders throughout the year, and Korschgen (1977) studied weight changes in selected organs and muscles mainly during incubation. Neither study presented detailed data on the changes in weight and body composition that occur in laying when the rate of energy and nutrient expenditure is substantial. Our aim was to investigate the extent and pattern of endogenous nutrient and energy expenditure during laying and incubation in female Eiders breeding in the high Arctic. We also provide comparative data from a population breeding near the species' northern range limit. STUDY AREA AND METHODS The study was conducted at Ny-Alesund in the Kongsfjord region of West Spitsbergen (78?55'N, 660 The Auk 107: 660-668. October 1990 This content downloaded from 157.55.39.104 on Sun, 19 Jun 2016 05:47:30 UTC All use subject to http://about.jstor.org/terms October 1990] Arctic Breeding in Female Eiders 661 12000'E) in the Svalbard (Norway) archipelago during 1982. Eiders returned to the Kongsfjord region around mid-April after wintering farther south. Birds concentrated in patches of open water near the mouth of the fjord to forage before nesting. Pairs began flights to the inner fjord in late May, apparently to investigate ice conditions near breeding islands there. Eiders usually concentrate breeding efforts on five major islands in the inner Kongsfjord, as well as near the research station at Ny-Alesund. Laying often begins at different times on adjacent islands because of local variation in ice conditions (Parker and Mehlum in press). Consequently, all birds collected for body composition analysis were collected at the Ny-Alesund colony. Females were collected at four precisely known stages of the reproductive cycle designated as (1) two-three weeks before laying: females collected shortly after pairs began to arrive near the Ny-Alesund colony (i.e. 2-3 weeks before laying began [n = 4]); (2) prelaying: females with large follicles collected just before laying and within 3 days of commencement of laying in the colony (n = 7); (3) postlaying: females collected after 2-3 days of incubation (mean = 2.1), each checked regularly during laying to minimize the possibility of dump nesting or loss of eggs to predators (n = 7); and (4) hatching: females collected on the nest with hatched or hatching young (n = 8). An additional 14 females at this stage were captured and weighed to increase the sample size of bird weights at hatching. Immediately after collection, birds were weighed (total carcass weight) on a Salter spring scale to the nearest 10 g. They were then completely hand-plucked and singed. The intestines (emptied), gizzard (emptied), liver, both pectoral muscles, and the ovary with oviduct were excised, and wet weights were recorded to the nearest 0.1 g. The featherless carcass (including excised muscles and organs) was weighed (featherless carcass weight) and frozen at 20?C in double plastic bags. In preparation for the body composition analysis, the frozen material was sawed on a band saw into pieces and homogenized in a food grinder. The water content of each carcass was determined by drying duplicate 15-g samples to constant weight in a vacuum oven for 2 days at room temperature and ca. 1 day at 30?C. The remaining material was burned at 600?C to constant weight (for approx. 4 h) to obtain ash values. Total lipid was determined with a modified Folch extraction (chloroform-methanol), and total protein by the macro-Kjeldahl method with protein expressed as the product of nitrogen times 6.25. Both lipid and protein determinations were based on 6-10 g samples, usually in triplicate (Holm et al. 1973). Calculation of energy content in lipid is based on a conversion factor of 38.53 kilojoules per gram (kJ g-1), as direct calorimetry of fat samples (n = 9) from both fat and lean birds gave this same value. The energy content of protein was derived using a standard conversion factor of 19.67 kJ.g-l (Pullar and Webster 1977). The energy in subsamples of total homogenate from nine different carcasses, including individuals from each of the four classes of breeding birds, was determined by direct calorimetry. These direct values were compared with total energy values of the same birds derived by calculation as a check for accuracy. Energy values throughout are expressed in kilojoules (4.184 kJ = 1 kcal). Samples of homogenate from the fattest bird collected 2-3 weeks before laying and the leanest bird collected at hatching were analyzed for fatty-acid composition using standard gas chromatography methods. All analyses were done at the Institute for Nutrition Research, School of Medicine, University of Oslo, Oslo, Norway. Statistical comparisons of carcass, organ, muscle, lipid, protein, water, and ash weight were made using one-way analysis of variance with significance level set at P < 0.05.

Hyperthermus butylicus, a hyperthermophilic sulfur-reducing archaebacterium that ferments peptides.

Abstract: The hyperthermophilic peptide-fermenting sulfur archaebacterium Hyperthermus butylicus was isolated from the sea floor of a solfataric habitat with temperatures of up to 112 degrees C on the coast of the island of Sao Miguel, Azores. The organism grows at up to 108 degrees C, grows optimally between 95 and 106 degrees C at 17 g of NaCl per liter and pH 7.0, utilizes peptide mixtures as carbon and energy sources, and forms H2S from elemental sulfur and molecular hydrogen as a growth-stimulating accessory energy source but not by sulfur respiration. The same fermentation products, CO2, 1-butanol, acetic acid, phenylacetic acid, and a trace of hydroxyphenylacetic acid, are formed both with and without of S0 and H2. Its ether lipids, the absence of a mureine sacculus, the nature of the DNA-dependent RNA polymerase, and phylogenetic classification by DNA-rRNA cross-hybridization characterize H. butylicus as part of a novel genus of the major branch of archaebacteria comprising the orders Thermoproteales and Sulfolobales, representing a particularly long lineage bifurcating with the order Sulfolobales above the branching off of the genus Thermoproteus and distinct from the genera Desulfurococcus and Pyrodictium.

Tamper resistant packaging for information protection in electronic circuitry

Abstract: A tamper-resistant package for protecting information stored in electronic circuitry is described. An energy source provides energy (electrical current, optical energy, microwave energy or RF energy, for example) within a region occupied by the circuitry to be protected. The energy is applied to an energy distribution system comprising a path or paths for energy distribution. Sensing means are provided which respond to the distribution system for sensing an intrusion. The distribution system includes an arrangement for changing or altering the path or paths over which the energy travels or altering the topology of the path or paths. The sensing means is informed of the appearance of the distribution system and senses an intrusion by comparing the appearance of the path(s) with the predicted appearance. In one embodiment, electrical current is selectively applied to a subset of electrical conductors. The pattern of current flowing in the conductors is sensed and compared to an expected pattern which is determined by the subset of energized conductors. Intrusion is evidenced by a disparity between the pattern of energized paths sensed by the sensing means compared to the pattern predicted by the sensing means. Dynamically varying the identity of the energized paths makes it difficult for an attacker to bypass the tamper detection.

Glucose, glutamine and inorganic phosphate in early development of the pig embryo in vitro.

Abstract: Pig embryos at the 1- or 2-cell stage (before the 'block' to development in vitro) were cultured in 8 different media derived from Krebs'-Ringer-bicarbonate medium. A 2 x 2 x 2 factorial arrangement was used for the treatments, with glucose, glutamine and phosphate being the major effects tested. Embryos were obtained from sows approximately 44-48 h after the observation of oestrus, with the majority being at the 1-cell stage. Embryos from each female were randomly assigned to each treatment. After in-vitro culture, all embryos were scored for the stage of development attained and stained to determine final cell number. Significant effects were evident due to female, glucose, glutamine, a phosphate x glucose interaction and a glutamine x glucose interaction. None of the media components tested was inhibitory to embryo development. The greatest development (45-60% morula or blastocyst) was achieved with glucose and glutamine (both alone and in combination) in the media, demonstrating that an amino acid can serve as the sole energy source for complete preimplantation embryonic development in vitro.

Bacterial periplasmic permeases belong to a family of transport proteins operating from Escherichia coli to human: Traffic ATPases

Abstract: Bacterial periplasmic transport systems are complex permeases composed of a soluble substrate-binding receptor and a membrane-bound complex containing 2-4 proteins. Recent developments have clearly demonstrated that these permeases are energized by the hydrolysis of ATP. Several in vitro systems have allowed a detailed study of the essential parameters functioning in these permeases. Several of the component proteins have been shown to interact with each other and the actual substrate for the transport process has been shown to be the liganded soluble receptor. The affinity of this substrate for the membrane complex is approximately 10 microM. The involvement of ATP in energy coupling is mediated by one of the proteins in the membrane complex. For each specific permease, this protein is a member of a family of conserved proteins which bind ATP. The similarity between the members of this family is high and extends itself beyond the consensus motifs for ATP binding. Interestingly, over the last few years, several eukaryotic membrane-bound proteins have been discovered which bear a high level of homology to the family of the conserved components of bacterial periplasmic permeases. Most of these proteins are known to, or can be inferred to participate in a transport process, such as in the case of the multidrug resistance protein (MDR), the STE6 gene product of yeast, and possibly the cystic fibrosis protein. This homology suggests a similarity in the mechanism of action and possibly a common evolutionary origin. This exciting development will stimulate progress in both the prokaryotic and eukaryotic areas of research by the use of overlapping procedures and model building. We propose that this universal class of permeases be called 'Traffic ATPases' to distinguish them from other types of transport systems, and to highlight their involvement in the transport of a vast variety of substrates in either direction relative to the cell interior and their use of ATP as energy source.

Organizational aspects of engineering system safety: the case of offshore platforms.

Abstract: Organizational errors are often at the root of failures of critical engineering systems. Yet, when searching for risk management strategies, engineers tend to focus on technical solutions, in part because of the way risks and failures are analyzed. Probabilistic risk analysis allows assessment of the safety of a complex system by relating its failure probability to the performance of its components and operators. In this article, some organizational aspects are introduced to this analysis in an effort to describe the link between the probability of component failures and relevant features of the organizaton. Probabilities are used to analyze occurrences of organizational errors and their effects on system safety. Coarse estimates of the benefits of certain organizational improvements can then be derived. For jacket-type offshore platforms, improving the design review can provide substantial reliability gains, and the corresponding expense is about two orders of magnitude below the cost of achieving the same result by adding steel to structures.

The Influence of Diet on the Appearance of New Lesions in Human Coronary Arteries

Abstract: The Cholesterol Lowering Atherosclerosis Study, a randomized, placebo-controlled trial of blood lipid lowering, demonstrated significant benefit in 2-year coronary angiograms. Using angiograms of subjects in the Cholesterol Lowering Atherosclerosis Study who received a placebo and 24-hour dietary recall data, we performed an epidemiologic study of risk factors for formation of new atherosclerotic lesions. Age and baseline plus on-trial lipid levels, blood pressure levels, and diet variables were included. Significant dietary energy sources were protein, carbohydrate, alcohol, total fat, and polyunsaturated fat. Each quartile of increased consumption of total fat and polyunsaturated fat was associated with a significant increase in risk of new lesions. Increased intake of lauric, oleic, and linoleic acids significantly increased risk. Subjects in the Cholesterol Lowering Atherosclerosis Study in whom new lesions did not develop increased dietary protein to compensate for reduced intake of fat by substituting low-fat meats and dairy products for high-fat meats and dairy products. These results indicate that when total and saturated fat intakes are reduced to levels recommended by the National Cholesterol Education Program, protein and carbohydrate are preferred substitutes for fat calories, rather than monounsaturated or polyunsaturated fat.

Oxidation of reduced inorganic sulphur compounds by acidophilic thiobacilli.

Abstract: Acidophilic sulphur-oxidizing bacteria were first isolated from acidic mine effluents [1], where they are the causative agents of the environmental problem acid mine drainage. Furthermore, acidophilic thiobacilli are at least partially responsible for the development of acid sulphate soils [2]. Over the past decades there has been a growing interest in the application of this type of organisms in the biological leaching of metal ores [3] and the biological dcsulphuriz~tion of coal [4,5]. The key reaction in the processes mentioned above is the biological oxidation of pyrite (Fe:S2) to ferric sulphate and sulphuric acid. Thiobacillus ferrooxidans is widely used as a model organism to study the biological oxidation of pyrite. T. ferrooxidans is an obligately chemolithoautotrophic, aerobic. Gram-negative bacterium. Energy sources for autotrophic growth include ferrous iron and a number of reduced inorganic sulphur compounds [6]. Most studies into the physiology and bio-en-

Characterization of the H2- and CO-dependent chemolithotrophic potentials of the acetogens Clostridium thermoaceticum and Acetogenium kivui.

Abstract: Strains of Clostridium thermoaceticum were tested for H2- and CO-dependent growth in a defined medium containing metals, minerals, vitamins, cysteine-sulfide, CO2-bicarbonate, and H2 or CO. Ten of the thirteen strains tested grew at the expense of H2 and CO, and C. thermoaceticum ATCC 39073 was chosen for further study. The doubling times for H2- and CO-dependent growth under chemolithotrophic conditions (the defined medium with nicotinic acid as sole essential vitamin and sulfide as sole reducer) were 25 and 10 h, respectively. Product stiochiometries for chemolithotrophic cultures approximated: 4.1H2 + 2.4CO2----CH3COOH + 0.1 cell C + 0.3 unrecovered C and 6.8CO----CH3COOH + 3.5CO2 + 0.4 cell C + 0.9 unrecovered C. H2-dependent growth produced significantly higher acetate concentrations per unit of biomass synthesized than did CO- or glucose-dependent growth. In contrast, the doubling time for H2-dependent growth under chemolithotrophic conditions (the defined medium without vitamins and sulfide as sole reducer) by Acetogenium kivui ATCC 33488 was 2.7 h; as a sole energy source, CO was not growth supportive for A. kivui. The YH2 values for A. kivui and C. thermoaceticum were 0.91 and 0.46 g of cell dry weight per mol of H2 consumed, respectively; the YCO value for C. thermoaceticum was 1.28 g of cell dry weight per mol of CO consumed. The specific activities of hydrogenase and CO dehydrogenase in both acetogens were influenced by the energy source utilized for growth and were significantly lower in C. thermoaceticum than in A. kivui. With extracts of H2-cultivated cells and benzyl viologen as electron acceptor, the Vmax values for hydrogenase from C. thermoaceticum and A. kivui were 155.7 and 1,670 micromoles of H2 oxidized per min mg of protein, respectively; the Vmax values for CO dehydrogenase from C. thermoaceticum and A. kivui were 90.6 and 2,973 micromoles of CO oxidized per min per mg of protein, respectively.

Correlation of reservoired gases using the carbon isotopic compositions of wet gas components

Abstract: The carbon isotopic compositions of the wet gas components, particularly propane, isobutane, and normal butane, have been found to be particularly valuable for correlating one reservoired gas with another. The usefulness of these components for correlation results from their carbon isotopic compositions reflecting both the nature of their source and their maturity. This source control is strongest for gases derived from the more highly structured types of kerogen (i.e., woody-coaly; type III), although the wet gas components' carbon isotopic compositions of most gases are at least partly controlled by their source for levels of maturity below the point at which thermal destruction of the wet components occurs. As a result, the wet gas components are found to provide more ositive correlations than is methane alone. Three exploration examples illustrate the use of the carbon isotopic compositions of the wet gas components for correlation: the Leduc reef trend of Alberta, Canada; the Sleipner area in the North Sea; and the Lena field, offshore Louisiana, United States. The three examples also illustrate the need to integrate geochemical interpretations with regional geology to obtain a good understanding of the hydrocarbon source.

Adaptations by Invertebrate Larvae for Nutrient Acquisition from Seawater

Abstract: Unlike life on land, animals that live in seawater are surrounded by a medium that contains organic nutrients in dilute solution. Larval forms of soft-bodied marine invertebrates are adapted to take advantage of the fact that most of the organic carbon in their environment is in solution as dissolved organic material (DOM). New evidence for the importance of DOM to metazoans is presented by showing that larval forms can increase in biomass, even in the absence of paniculate foods. Such increases occurred only in those species capable of transporting DOM. The physiological basis for using DOM as an energy source is dependent upon an increased transport capacity for DOM as growth proceeds. Using bivalve larvae, mass coefficients and exponents were determined for (i) alanine transport rates and (ii) metabolic rates. These coefficients were not statistically different when determined over the life span of a larva. Thus, as growth proceeds, these larvae increase their ability to obtain a potential supply of metabolic fuel (DOM) in direct proportion to the increase in their metabolic demand. The percent of this increased transport capacity that larvae could actually utilize in nature will depend upon the substrate concentrations in their environment. Current views on what these concentrations are in seawater may be altered as more attention is given to the fine scale distributions of organic chemicals in the ocean. After DOM has been transported by the animal, its metabolic fate can now be rigorously studied using bacteria-free larvae. Measurements of amino acid synthesis in larvae cultured under axenic conditions suggest that a much greater plasticity may exist in the biochemical requirements of larvae for dietary amino acids.