Production and heat treatment of cast graphitic steels with additions of niobium

The optimal combination of the mechanical characteristics of austempered spheroidal graphitic cast steel together with modern casting techniques yielded an economically promising product. The maximum potentiality of the usage of these steels is related to fabrication and characterization techniques, among which, one of the most important is the cooling diagram (TTT curve). In this work, 3 heats of graphitic steels with the following nominal compositions were cast: 1.0%C, 2.3%Si, 0.4% Mn, and with niobium contents of 0.0%, 0.5% and 1.0%. TTT curves were determined by dilatometric testing and test specimens of these steels were austempered. The samples were then characterized by hardness testing and optical and SEM microscopy. Tensile, impact (no notch) and wear testing were also performed. The addition of niobium produced significant alterations in the TTT diagrams. Increasing niobium content moves the pearlite transformation nose to the right and the bainitic transformation nose to the left. Tensile strength of these alloys was high, in the range of 1700 MPa and impact values were around of 45 Joules for alloy with 1% Nb, 49 Joules for alloy with 0.5% Nb and fracture did not occur for the alloy without the addition of Nb.

Oxidative stress, superoxide production, and apoptosis of neutrophils in dogs with chronic kidney disease

Oxidative stress is a key component in the immunosuppression of chronic kidney disease (CKD), and neutrophil function may be impaired by oxidative stress. To test the hypothesis that in uremic dogs with CKD, oxidative stress is increased and neutrophils become less viable and functional, 18 adult dogs with CKD were compared with 15 healthy adult dogs. Blood count and urinalysis were done, and the serum biochemical profile and plasma lipid peroxidation (measurement of thiobarbituric acid reactive substances) were determined with the use of commercial reagents. Plasma total antioxidant capacity (TAC) was measured with a spectrophotometer and commercial reagents, superoxide production with a hydroethidine probe, and the viability and apoptosis of neutrophils with capillary flow cytometry and the annexin V-PE system. The plasma concentrations of cholesterol (P = 0.0415), creatinine (P < 0.0001), and urea (P < 0.0001) were significantly greater in the uremic dogs than in the control dogs. The hematocrit (P = 0.0004), urine specific gravity (P = 0.015), and plasma lipid peroxidation (P < 0.0001) were significantly lower in the dogs that were in late stages of CKD than in the control group. Compared with those isolated from the control group, neutrophils isolated from the CKD group showed a higher rate of spontaneous (0.10 ± 0.05 versus 0.49 ± 0.09; P = 0.0033; median ± standard error of mean) and camptothecin-induced (18.53 ± 4.06 versus 44.67 ± 4.85; P = 0.0066) apoptosis and lower levels of superoxide production in the presence (1278.8 ± 372.8 versus 75.65 ± 86.6; P = 0.0022) and absence (135.29 ± 51.74 versus 41.29 ± 8.38; P = 0.0138) of phorbol-12-myristate-13-acetate stimulation. Thus, oxidative stress and acceleration of apoptosis occurs in dogs with CKD, the apoptosis diminishing the number of viable neutrophils and neutrophil superoxide production.

Manure production and mineral excretion in feces of gilts fed ractopamine

A study was conducted to evaluate the feces+urine produced per animal (FUPA), dry matter, mineral matter, organic matter, nitrogen, phosphorus, potassium and sulfur in feces of gilts fed diets with increasing levels of ractopamine (0, 5, 10 and 15 mg kg-1 of diet). A total of 468 finishing gilts were allotted into 36 pens. In two days of each week, feces and urine were daily sampled in four pens per treatment, quantifying the feces+urine. To determine the characterization of feces, two samples per week were taken daily, in nine pens per treatment. It was used a split plot design, considering the ractopamine level as the plot and the weeks as the subplots. There was no reduction in nitrogen amount in feces. An interaction was detected between ractopamine concentrations and weeks for FUPA and phosphorus, potassium and sulfur in feces. Ractopamine addition in diets for gilts has reduced the feces+urine production and nitrogen and phosphorus excretion. Higher values estimated for potassium content in feces of animals fed diets with 10 and 15 mg of ractopamine kg-1 were found between the second and third week. Increasing levels of ractopamine from 5 to 15 mg kg-1 promoted higher excretion of sulfur over the weeks of supply.

PRODUCTION AND CHEMICAL COMPOSITION OF VEGETABLES HARDWOOD IN HYDROPONICS

The hydroponic cultivation of vegetables has increased markedly in recent years, however, little is known about its chemical composition, which is of extreme importance in view of changing food habits of a considerable fraction of the population seeking food quality. For this reason, cultivation of watercress, chicory, rocket and lettuce American (Lucy Brown) and smooth (cv. Regina) were grown in hydroponics, NFT system, aiming to evaluate the yield, nitrate content and chemical composition. The experiment was conducted in a greenhouse at the Universidade Federal de Santa Catarina, Florianopolis city in the Santa Catarina State (Brazil), from may to july 2004 under a completely randomized design with four replications. The spacing used was 25 x 25 cm for the crops of watercress, chicory and lettuce (cv. Lucy Brown and cv. Regina) and 5 x 5 cm to the rocket. The traits were: number of leaves, nitrate content and chemical composition of vegetables. The lettuce cv. Regina and chicory had higher number of leaves per plant. The watercress had lower water content and higher dry mass of shoots. The largest increase in fresh weight was obtained in chicory, lettuce, cv. Regina. Higher levels of lipids, protein, ash, carbohydrates, calories, fiber and nitrate were obtained from the watercress. The rocket had lower values for the variables fresh and dries the whole plant, shoot and root and leaf number per plant. All cultures showed good visual appearance, low calorie and nitrate levels suitable for human consumption.

White lupin (Lupinus albus L.), the neglected multipurpose crop: Its production and utilization in the mixed crop-livestock farming system of Ethiopia

A survey was conducted to generate holistic information on the production and utilization of local white lupin in two lupin growing districts, namely, Mecha and Sekela, representing mid and high altitude areas, respectively in North-western Ethiopia. During the survey, two types of participatory rural appraisal (PRA) techniques, namely, individual farmer interview (61 farmers from Mecha and 51 from Sekela) and group discussion (with 20 farmers from each district) were employed. There are significant differences (P<0.05) between the two study districts for the variables like total land holding, frequency of ploughing during lupin planting, days to maturity, lupin productivity, and number of days of soaking lupin in running water. However, there are no significant differences (P>0.05) between the two study districts for the variables like land allocated for lupin cultivation, lupin seed rate, lupin soaking at home, lupin consumption per family per week and proportion of lupin used for household consumption. The use of the crop as livestock feed is negligible due to its high alkaloid content. It is concluded that the local white lupin in Ethiopia is a valuable multipurpose crop which is being cultivated in the midst of very serious shortage of cropland. Its ability to maintain soil fertility and serve as a source of food in seasons of food scarcity makes it an important crop. However, its bitter taste due to its high alkaloid content remains to be a big challenge and any lupin improvement strategy has to focus on minimizing the alkaloid content of the crop.

Primary production and chlorophyll a in waters of the Kara Sea in September 2007

These studies were performed from September 10 to 29, 2007 in the Kara Sea in transects westward of the Yamal Peninsula, near the St. Anna Trough, in the Ob River estuary (Obskay Guba), and on the adjacent shelf. Concentration of chlorophyll a in the euphotic layer varied from 0.02 to 4.37 µg/l, aver. 0.76 µg/l. Primary production in the water column varied from 10.9 to 148.0 mg C/m**2/day (aver. 56.9 mg C/m**2/day). It was shown that frontal zones divided the Kara Sea into distinct areas with different productivities. Maximum levels of primary production were measured in the deep part of the Yamal transect (132.4 mg C/m**2/day) and the shallow Kara Sea shelf near the Ob River estuary (74.9 mg C/m**2/day). Characteristics of these regions were low salinity of the surface water layer (19-25 psu) and elevated silicon concentration (12.8-28.1 µg-atom/l). It is explainable by river runoff. Frontal zones of the Yamal current within the Yamal and Ob transects showed high assimilation numbers reached to 2.32 and 1.49 mg C/mg Chl/hr, respectively; they were maximal for studied areas.

Seasonal variations of contribution of large and fine fractions of phytoplankton to primary production and chlorophyll a in the Sevastopol Bay from April 1985 till March 1986

It has been shown that in the Sevastopol Bay during the year primary production and chlorophyll "a" created by picoplankton (0.45-2.5 µm) consisted on the average 20-44% of total production. It was approximately a half of the level for oligotrophic waters of the ocean. Picoplankton of waters studied is represented by eucaryotes, cell diameter of which is, as a rule, about 2-3 µm. Contribution of the finest fraction of phytoplankton (0.43-0.85 µm) to primary production and con¬tent of chlorophyll "a" was insignificant (0-4%).

Seawater carbonate chemistry, calcification, primary production and respiration of a temperate rhodolith Lithothamnion corallioides in a laboratory experiment

Coralline algae are considered among the most sensitive species to near future ocean acidification. We tested the effects of elevated pCO2 on the metabolism of the free-living coralline alga Lithothamnion corallioides ("maerl") and the interactions with changes in temperature. Specimens were collected in North Brittany (France) and grown for 3 months at pCO2 of 380 (ambient pCO2), 550, 750, and 1000 µatm (elevated pCO2) and at successive temperatures of 10°C (ambient temperature in winter), 16°C (ambient temperature in summer), and 19°C (ambient temperature in summer +3°C). At each temperature, gross primary production, respiration (oxygen flux), and calcification (alkalinity flux) rates were assessed in the light and dark. Pigments were determined by HPLC. Chl a, carotene, and zeaxanthin were the three major pigments found in L. corallioides thalli. Elevated pCO2 did not affect pigment content while temperature slightly decreased zeaxanthin and carotene content at 10°C. Gross production was not affected by temperature but was significantly affected by pCO2 with an increase between 380 and 550 µatm. Light, dark, and diel (24 h) calcification rates strongly decreased with increasing pCO2 regardless of the temperature. Although elevated pCO2 only slightly affected gross production in L. corallioides, diel net calcification was reduced by up to 80% under the 1,000 µatm treatment. Our findings suggested that near future levels of CO2 will have profound consequences for carbon and carbonate budgets in rhodolith beds and for the sustainability of these habitats.

Low metal content Co and Ni alumina supported catalysts for the CO2 reforming of methane

Low metal content Co and Ni alumina supported catalysts (4.0, 2.5 and 1.0 wt% nominal metal content) have been prepared, characterized (by ICP-OES, TEM, TPR-H2 and TPO) and tested for the CO2 reforming of methane. The objective is to optimize the metal loading in order to have a more efficient system. The selected reaction temperature is 973 K, although some tests at higher reaction temperature have been also performed. The results show that the amount of deposited carbon is noticeably lower than that obtained with the Co and Ni reference catalysts (9 wt%), but the CH4 and CO2 conversions are also lower. Among the catalysts tested, the Co(1) catalyst (the value in brackets corresponds to the nominal wt% loading) is deactivated during the first minutes of reaction because CoAl2O4 is formed, while Ni(1) and Co(2.5) catalysts show a high specific activity for methane conversion, a high stability and a very low carbon deposition.

Physical characteristics and bacterial production and respiration at stations sampled during 2008 in the eastern Beaufort Sea

Bacterial carbon demand, an important component of ecosystem dynamics in polar waters and sea ice, is a function of both bacterial production (BP) and respiration (BR). BP has been found to be generally higher in sea ice than underlying waters, but rates of BR and bacterial growth efficiency (BGE) are poorly characterized in sea ice. Using melted ice core incubations, community respiration (CR), BP, and bacterial abundance (BA) were studied in sea ice and at the ice-water interface (IWI) in the Western Canadian Arctic during the spring and summer 2008. CR was converted to BR empirically. BP increased over the season and was on average 22 times higher in sea ice as compared with the IWI. Rates in ice samples were highly variable ranging from 0.2 to 18.3 µg C/l/d. BR was also higher in ice and on average ~10 times higher than BP but was less variable ranging from 2.39 to 22.5 µg C/l/d. Given the high variability in BP and the relatively more stable rates of BR, BP was the main driver of estimated BGE (r**2 = 0.97, P < 0.0001). We conclude that microbial respiration can consume a significant proportion of primary production in sea ice and may play an important role in biogenic CO2 fluxes between the sea ice and atmosphere.

Leasing and western development of coal [microform] : hearings before the Subcommittee on Energy Production and Supply of the Committee on Energy and Natural Resources, United States Senate, Ninety-fifth Congress, first session ...

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The effects of nitrogen application and assimilate availability on engorged pollen production and spikelet sterility in rice

Increased rates of nitrogen fertilizer application lead to increased spikelet sterility. A field experiment was conducted to investigate the effects on engorged pollen production and spikelet sterility, of nitrogen and assimilate availability during microspore development, in two rice cultivars (Doongara and Amaroo) grown under two different water depths. Despite the temperature not being low enough during microspore development to cause spikelet sterility, the number of engorged pollen grains was lower in cv. Doongara than in cv. Amaroo. Nitrogen application decreased the number of engorged pollen grains per anther through increased spikelet density. Nitrogen application increased spikelet sterility as a result of increased panicle density showing pronounced indirect effect of N on spikelet sterility. Engorged pollen number was also closely related (r = -0.636*) to the nitrogen content of the leaf blade, indicating a direct negative effect of plant N status on engorged pollen production. The results suggest that the intrinsic pollen producing ability is the key element in the difference in cold tolerance between the two cultivars, particularly under high N rates. Opening the canopy for increased solar radiation interception by the treated plants increased the level of engorged pollen, indicating the importance of immediate assimilate availability for engorged pollen production. Shading reduced crop growth rate, but did not effect engorged pollen production. There was no effect of variation in assimilates production on spikelet sterility.

Production and action of local mediators in the rat gastric mucosa

This study concerns the production and action of the local mediators nitric oxide (NO) and prostaglandin E2 (PGE2) in the rat gastric mucosa. The major objectives were: (i) to determine which mucosal cell type(s) contained NO synthase activity, (ii) to establish the functional role(s) of NO in the gastric mucosa and (iii) to investigate regulation of gastric PGE2 production. Gastric mucosal cells were isolated by pronase digestion coupled with intermittent calcium chelation and were separated by either density-gradient centrifugation or by counterflow elutriation. The distribution of Ca2+ -dependent NO synthase activity, measured via the conversion of [14C]-L-arginine to [14C]-L- citrulline, paralleled the distribution of mucous cells in elutriated fractions. Pre-treatment of rats with lipopolysaccharide caused the induction of Ca2+ -independent NO synthase in the elutriator fractions enriched with mucous cells. Incubation of isolated cells with the NO donor isosorbide dinitrate (ISDN) produced a concentration-dependent increase in the guanosine 3',-5'-cyclic monophosphate (cGMP) content which was accompanied by a concentration-dependent increase in release of immunoreactive mucin. Intragastric administration of ISDN of dibutyryl cGMP in vivo increased the thickness of the mucus layer overlying the gastric mucosa. The NO donor S-nitroso-N-acetylpenicillamine (SNAP) produced a concentration-dependent inhibition (IC50 247 μM) of histamine-stimulated aminopyrine accumulation, a measure of secretory activity, in cell suspensions containing > 80% parietal cells. SNAP increased the cGMP content of the suspension but did not decrease cellular viability, glucose oxidation or adenosine 3',5'-cyclic monophosphate content. The inhibitory effect of SNAP was observed in permeabilised cells stimulated with ATP and was stereospecifically blocked by preincubation with Rp-8-bromoguanosine 3'-5'-monophosphorothioate, which inhibits activation of cGMP-dependent protein kinase. Stimulation of PGE2 release by bradykinin in a low density cell fraction, enriched with parietal cells and devoid of vascular endothelial cells and macrophages, involved a bradykinin B1 receptor. In summary, NO synthase activity is probably present in gastric mucous epithelial cells. NO may promote mucus secretion by elevation of cGMP. NO donors inhibit acid secretion at a specific site and their action may involve cGMP. The bradykinin B1 receptor is involved with PGE2 production in the gastric mucosa.