Showing papers by "Applied Science Private University published in 1997"

Deferribacter thermophilus gen. nov., sp. nov., a Novel Thermophilic Manganese- and Iron-Reducing Bacterium Isolated from a Petroleum Reservoir

Abstract: A thermophilic anaerobic bacterium, designated strain BMAT (T = type strain), was isolated from the production water of Beatrice oil field in the North Sea (United Kingdom). The cells were straight to bent rods (1 to 5 by 0.3 to 0.5 μ) which stained gram negative. Strain BMAT obtained energy from the reduction of manganese (IV), iron(III), and nitrate in the presence of yeast extract, peptone, Casamino Acids, tryptone, hydrogen, malate, acetate, citrate, pyruvate, lactate, succinate, and valerate. The isolate grew optimally at 60°C (temperature range for growth, 50 to 65°C) and in the presence of 2% (wt/vol) NaCl (NaCl range for growth, 0 to 5% [wt/vol]). The DNA base composition was 34 mol% G+C. Phylogenetic analyses of the 16S rRNA gene indicated that strain BMAT is a member of the domain Bacteria. The closest known bacterium is the moderate thermophile Flexistipes sinusarabici (similarity value, 88%). Strain BMAT possesses phenotypic and phylogenetic traits that do not allow its classification as a member of any previously described genus; therefore, we propose that this isolate should be described as a member of a novel species of a new genus, Deferribacter thermophilus gen. nov., sp. nov.

Complementarity Relation for Irreversible Process Derived from Stochastic Energetics

Abstract: When the process of a system in contact with a heat bath is described by the classical Langevin equation, use of the method of stochastic energetics [K. Sekimoto: J. Phys. Soc. Jpn. 66 (1997) 1234] enables us to derive the form of Helmholtz free energy and the dissipation function of the system. We are able to prove that the irreversible heat Q irr and the time lapse Δ t of an isothermal process obey the complementarity relation, Q irr Δ t ≥ k B T S min , where S min depends on the initial and the final values of the control parameters, but does not depend on the pathway between these values.

Anaerobaculum thermoterrenum gen. nov., sp. nov., a novel, thermophilic bacterium which ferments citrate

Abstract: A thermophilic anaerobic bacterium designated strain RWcit2T (T = type strain) was isolated from the production water of a petroleum reservoir. The cells of this organism are straight to slightly curved rods that are gram negative and nonmotile. Spore formation has not been demonstrated. Growth occurs at temperatures ranging from 28 to 60°C, with optimum growth occurring at 55°C, and at pH values ranging from 5.5 to 8.6, with optimum growth occurring between pH 7 and 7.6. Growth occurs in media containing 0 to 20 g of NaCl per liter, and optimum growth occurs in the presence of 10 g of NaCl per liter. Strain RWcit2T grows on a range of organic acids, including citrate, pyruvate, malate, fumarate, and tartrate; on protein extracts; and on a limited number of carbohydrates. Sulfur, thiosulfate, and cystine are reduced to hydrogen sulfide. Sulfate, sulfite, and nitrate are not reduced. The DNA base composition is 44 mol% G+C. The 16S ribosomal DNA sequence revealed that strain RWcit2T is a member of the domain Bacteria and forms a branch that is approximately equidistant from Dictyoglomus thermophilum and Thermoanaerobacter spp. (level of similarity, 82%). Strain RWcit2T cannot be placed in any previously described taxon based on its phylogenetic and physiological traits and is named Anaerobaculum thermoterrenum gen. nov., sp. nov.

Body habitus and coronary heart disease in men : A review with reference to methods of body habitus assessment

Abstract: Table 1 is a synopsis of the major findings from an extensive literature on the association between human body habitus and coronary heart disease. Whilst some studies have used quite sophisticated laboratory procedures to quantify body fat most have relied upon anthropometric measurements to determine some component of body habitus. Of these, body weight and height are the simplest measurements and are, therefore, well-suited to large-scale prospective studies. Height and weight are highly reproducible measurements, although in the short term, weight can have considerable physiological variation associated with gastric emptying and state of hydration. Less reliable measurements than height and weight are skinfolds and body circumferences, both of which have been used extensively in cross-sectional and prospective analyses. For skinfolds, both the inter and intra-observer variability is affected by the measurement technique, location of the skinfold site, the skinfold caliper used and skinfold compressibility. As measurement error has been shown to be a function of skinfold thickness, accurate and repeatable skinfold measurements are particularly difficult to make in the obese. In these subjects, it is not always possible to locate a specific anatomical bony landmark or to pull a parallel skinfold away from the underlying tissue. Furthermore, in the extremely obese it is sometimes possible for a skinfold to be thicker than the jaws of the currently available commercial calipers. Alternately, body circumferences are obtainable in all subjects and have greater reproducibility than skinfolds. They are, therefore, the preferred method in obese subjects. However, there is considerable work to be done to establish their association with body fatness. The evidence examined in this review suggests that body weight is a poor predictor of coronary heart disease. Some studies have reported no difference in the body weight of coronary heart disease patients compared to subjects free of the disease, others found the body weight of subjects with coronary heart disease to be slightly greater, and one found the body weight of cardiac patients to be less than controls. Height, however, is associated with coronary heart disease in prospective studies with long-term and shorter-term follow-up periods and case-control designs. Fetal, infant and childhood under-nutrition may link shorter adult height and susceptibility to cardiovascular disease. Many researchers have studied the relationship between overweight and coronary heart disease by using a surrogate measurement of body fatness such as relative weight or a weight-for-height index. In general, results produced by these studies suggest weight-for-height indices, particularly the often used body mass index, are not strong predictors of coronary heart disease. Indeed case-control designs have consistently failed to show a relationship between body mass index and coronary heart disease. Inconsistent results from prospective studies, however, are difficult to interpret. To further confuse the situation, the body mass index has been examined in relation to different coronary heart disease end-points and adjusted for different confounding variables. Explaining the inconsistent results on the basis of length of follow-up is also not straightforward. When follow-up periods exceed 20 years, and sample size is small, however, this closer association has not been found, even with a long follow-up period. Whilst some studies have found no association after 15, 13 and 12 years others have reported a relationship after 8.5, 10, 12, 10 and 7 years. The 22 year follow-up evidence from the Framingham Study shows the strongest 'independent' association between body mass index and coronary heart disease. (ABSTRACT TRUNCATED)

Synthesis and properties of a copper selective chelating resin containing a salicylaldoxime group

Abstract: A chelating ion-exchange phenol-formaldehyde polymer, poly(salicylaldoxime 3,5-diylmethylene) was synthesized and characterized. The sorption properties of the chelate-forming resin towards various divalent ions (Mg 2+ , Ca 2+ , Ni 2+ , Cu 2+ , Zn 2+ and Cd 2+ ) were studied by a static batch equilibration technique as a function of pH and contact time. The resin exhibited high selectivity towards Cu 2+ ions and showed fast rates of metal ion uptake, particularly for Cu 2+ which experienced >90% uptake in less than 1 h. In a dynamic column operation, it was demonstrated that the resin can be used for effective removal of copper ions from aqueous solutions.

Selenium associations in estuarine sediments: Redox effects

Abstract: Selenium (Se) is a contaminant of concern in environments affected by discharges from smelting and coal-burning industries. Experiments have been performed to investigate the phase associations of selenium in contaminated sediments under a range of controlled redox conditions. In this study, Se sediment associations were examined using the BCR sequential extraction technique after stabilisation at different redox states. It was shown that although most of the sediment-bound Se is associated with the operationally-defined “organic/sulfide” fraction, as the measured redox potential of the system is increased, more Se moves into the “exchangeable” and “iron/manganese oxyhydroxide” fractions. In these fractions, contaminants can be expected to be more bioavailable. As the mass of Se absorbed to sediments is typically at least an order of magnitude higher than the mass dissolved in porewaters, significant Se exposure may result from oxidative shifts in Se associations.

Amino acid degradation by the mesophilic sulfate-reducing bacterium Desulfobacterium vacuolatum

Abstract: Desulfobacterium vacuolatum strain IbRM was able to grow using casamino acids as a source of carbon, energy and nitrogen. Growth was accompanied by utilization of several amino acids and sulfide production. Proline and glutamate were used preferentially and to the greatest extent. Glycine, serine and alanine were used more slowly and only after proline and glutamate were used. Isoleucine, valine, leucine and aspartate decrease was slowest and occurred in a linear fashion throughout the growth phase. Amino acids used from casamino acids, excluding aspartate, were also used as single carbon, energy and nitrogen sources. As a single amino acid, aspartate could only be used as a nitrogen source. Aspartate was not used as an electron acceptor. No growth occurred on any amino acid in the absence of sulfate. As single substrates, isoleucine, proline and glutamate were oxidized without formation of acetate and with molar yields of 13.1, 9.4 and 7.7 g mol–1, respectively.

Effect of Varthemia iphionoides on blood glucose level of normal rats and rats with streptozocin-induced diabetes mellitus

Abstract: The use of plants for the treatment of patients with diabetes is common throughout the world. Varthemia iphionoides (Compositae) is widely distributed in Jordan, and its extract has been used in the treatment of patients with diabetes mellitus. The present study investigates the effect of an aqueous extract of V iphionoides on blood glucose levels in 12 normal rats and 12 rats with streptozocin-induced diabetes mellitus. The aqueous extract of V iphionoides reduced mean ± SEM blood glucose levels in normoglycemic rats from 95.4 ± 6.2 mg/dL to 75.3 ± 7.9 mg/dL and to 63 ± 10 mg/dL 4 and 24 hours, respectively, after administration of the extract by gastric intubation. No changes in the blood glucose concentration of normoglycemic rats were noticed 1 hour after administration. Significant decreases in the blood glucose levels of the hyperglycemic rats were observed 1, 4, and 24 hours after administration of the plant extract (from 535.8 ± 15.5 mg/dL to 145.7 ± 33.4 mg/dL, 247.5 ± 40.1 mg/dL, and 345.1 ± 65.5 mg/dL, respectively). However, no significant dose-response relationship was observed in the hyperglycemic rats on administration of various doses of the plant extract. Study results show that an aqueous extract of V iphionoides has hypoglycemic properties that should be investigated further.

Effect of Grain Fumigants on Lipids in Vivo and in Vitro

Abstract: The effect of current and potential grain fumigants on food lipids was examined in two ways. First, wheat was fumigated in vivo and the lipid extracted and compared with that from unfumigated wheat...

Evaluation of interaction coefficient in Al-Cu-H alloy

Abstract: The theory for interaction coefficient of alloying additions on hydrogen activity in Al alloys has been generally discussed. In particular, the interaction coefficient of Cu addition on the hydrogen activity for the Al-Cu-H system has been evaluated based on hydrogen solubility values in pure aluminum and in Al-Cu alloy measured at different Cu concentrations by means of Sieverts’ apparatus. The Cu addition was found to reduce the hydrogen solubility, and its effect on hydrogen solubility was evaluated by the interaction coefficient γ H Cu , which is a function of Cu-addition concentration and melt temperature. The evaluated interaction coefficient was converted into an alloy correction factor CF(A) and a temperature correction factor CF(T), which are employed in industrial hydrogen measurement techniques such as TELEGAS and ALSCAN.

Proximity effect and hot-electron diffusion in Ag/Al/sub 2/O/sub 3//Al tunnel junctions

Abstract: We have fabricated Ag/Al/sub 2/O/sub 3//Al tunnel junctions on Si substrates using a new process. This process was developed to fabricate superconducting tunnel junctions (STJs) on the surface of a superconductor. These junctions allow us to study the proximity effect of a superconducting Al film on a normal metal trapping layer. In addition, these devices allow us to measure the hot-electron diffusion constant using a single junction. Lastly these devices will help us optimize the design and fabrication of tunnel junctions on the surface of high-Z, ultra-pure superconducting crystals.

Hydrogenation of Toluene over La0.8Sr0.2Fe1-xCoxO3-z Perovskite Catalysts

Abstract: The hydrogenation of toluene over perovskites of composition La₀.₈Sr₀.₂Fe₁₋ₓ CoₓO₃₋z (x = 0.0, 0.2, 0.5, 0.8 and 1.0) is reported. The catalyst material has been prepared by the coprecipitation method using maleic acid as the complexing agent. The activity for the gas phase reaction of toluene and hydrogen at temperatures between 50 °C to 300 °C is reported for as-prepared and activated materials. The conversion has been found to be nearly temperature-independent over the as-prepared-per­ ovskites with a maximum of 40% conversion found for a composition La₀.₈Sr₀.₂Fe₀.₅Co₀.₅O₂.₈₆. Activation by an oxygen treatment at 500 °C was successful to enhance the activity of the Co-rich perovskites. All of these catalysts show a complete conversion of toluene at 100 °C, but activity decreases by time due to a reduction of the catalyst material. Again, La₀.₈Sr₀.₂Fe₀.₅Co₀.₅O₂.₈₆ exhibits the slowest loss of activity. A model for its special properties is mainly attributed to the p-type conduction behaviour. The conversion behaviour of the perovskite type catalysts investigated here is compared to the results obtained with noble-metal supported catalysts and it can be concluded, that the perovskites exhibit higher conversion rates, maximum temperatures and higher cracking onset temperatures than these.

Fuzzy logic image-clustering algorithm

Abstract: A fuzzy logic clustering algorithm to classify a given image into targets and backgrounds is presented. The algorithm forms clusters and is trained without supervision. The clustering is done on the basis of the statistical properties of the set of inputs. The algorithm features an adaptive mechanism for selecting the number of clusters, and it features an adaptive threshold. The problem of threshold selection is considered and the convergence of the algorithm is shown. The algorithm also does not require the number of clusters been known a priori. An example is given to illustrate the application of the algorithm.

Crystal Structure and Thermodynamical Behavior of Tetrabenzo(de,hi,op, st)pentacene Endoperoxide.

Abstract: The crystal structure of an endoperoxide of tetrabenzo[de,hi,op,st]pentacene (TBPA-O2) was determined by X-ray crystallography. The unusually long OO and CO bonds were rationalized by the characteristic molecular structure of TBPA-O2. The photochromic behavior between TBPA-O2 and TBPA was discussed based on the enthalpy difference between TBPA-O2 and TBPA + O2 and the thermodynamic parameters of the extrusion reaction of oxygen from TBPA-O2.