Influence of agronomic and climatic factors on Fusarium infestation and mycotoxin contamination of cereals in Norway

A total of 602 samples of organically and conventionally grown barley, oats and wheat was collected at grain harvest during 2002-2004 in Norway. Organic and conventional samples were comparable pairs regarding cereal species, growing site and harvest time, and were analysed for Fusarium mould and mycotoxins. Agronomic and climatic factors explained 10-30% of the variation in Fusarium species and mycotoxins. Significantly lower Fusarium infestation and concentrations of important mycotoxins were found in the organic cereals. The mycotoxins deoxynivalenol (DON) and HT-2 toxin (HT-2) constitute the main risk for human and animal health in Norwegian cereals. The impacts of various agronomic and climatic factors on DON and HT-2 as well as on their main producers F. graminearum and F. langsethiae and on total Fusarium were tested by multivariate statistics. Crop rotation with non-cereals was found to reduce all investigated characteristics significantly--mycotoxin concentrations as well as various Fusarium infestations. No use of mineral fertilisers and herbicides was also found to decrease F. graminearum, whereas lodged fields increased the occurrence of this species. No use of herbicides was also found to decrease F. langsethiae, but for this species the occurrence was lower in lodged fields. Total Fusarium infestation was decreased with no use of fungicides or mineral fertilisers, and with crop rotation, as well as by using herbicides and increased by lodged fields. Clay and to some extent silty soils seemed to reduce F. graminearum in comparison with sandy soils. Concerning climate factors, low temperature before grain harvest was found to increase DON; and high air humidity before harvest to increase HT-2. F. graminearum was negatively correlated with precipitation in July but correlated with air humidity before harvest. F. langsethiae was correlated with temperature in July. Total Fusarium increased with increasing precipitation in July. Organic cereal farmers have fewer cereal intense rotations than conventional farmers. Further, organic farmers do not apply mineral fertiliser or pesticides (fungicides, herbicides or insecticides), and have less problem with lodged fields. The study showed that these agronomic factors were related to the infestation of Fusarium species and the concentration of mycotoxins. Hence, it is reasonable to conclude that farming system (organic versus conventional) impacts Fusarium infestation, and that organic management tends to reduce Fusarium and mycotoxins. However, Fusarium infestation and mycotoxin concentrations may be influenced by a range of factors not studied here, such as local topography and more local climate, as well as cereal species and variety.     

CATALYTIC HYDROTREATMENT OF PETROLEUM RESIDUE

ABSTRACT

Iraqi reduced crude (350°C+) with a sulfur content of 4.3 wt% and a total metal content (Ni+V) of 141 WPPM was n-heptane deasphalted at specified conditions. The deasphalted oil (97.2 wt% of original residue) contains 4.1 wt% of sulfur and 103 ppm of metal. The original reduced crude and deasphalted oil were hydrotreated on a commercial Ni-Mo-alumina catalyst presulfided at specified conditions in a laboratory trickle-bed reactor. The reaction temperatures varied from 300 to 420°C with the liquid hourly space velocity (LHSV) ranging from 0.37 to 2.6 h^?1. Hydrogen pressure was kept constant throughout the experiments at 6.1 MPa, with a hydrogen/oil ratio of about 300 NLL^?1 (normal liters of hydrogen per liter of feedstock). Analysis for sulfur, nickel, vanadium and n-pentane asphaltenes were carried out for hydrotreated products from both the original residue and the deasphalted oil. The comparison of the results obtained for the hydrotreatment of deasphalted oil and original reduced crude indicates that the removal of sulfur, nickel and vanadium was higher for the deasphalted oil than those obtained for the non-deasphalted residue over the entire range of conversion. The exclusion of extremely high molecular weight asphaltenes by n-heptane deasphalting seems to improve the access of oil into catalyst pores resulting in higher desulfurization and conversion of the lower molecular weight asphaltenes. The sulfur content of n-pentane precipitated asphaltenes remained unchaneed with LHSV for various temperature for hydrotreated products produced from both deasphalted oil and original reduced crude.     

STRUCTURAL ANALYSIS ON THE AMYLOPECTIN OF WAXY-BARLEY LARGE STARCH GRANULES

The hydrolysis of waxy-barley starch by the α-amylase of B. subtilis was followed by gel chromatography on Sepharose CL 6B. A range of intermediate dextrins were initially produced, and at later stages dextrins with a degree of polymerization in the range 100–200 accumulated. Maltohexaose was produced simultaneously from the external chains. The hydrolysis of the amylopectin β-limit dextrin followed a similar pattern, though smaller amounts of the low-molecular weight material were formed. The sizes of the more resistant products in the hydrolysis mixtures suggested that the amylopectin contained two types of unit clusters with d.p. for the β-limit dextrins of 65 and 85. A regular model for the structure of the amylopectin that shows the possible mode of interconnection of the unit clusters is presented .     

Investigations on the metabolism and potentially adverse effects of ethoxyquin dimer, a major metabolite of the synthetic antioxidant ethoxyquin in salmon muscle

The feed additive ethoxyquin (EQ) is a commonly used synthetic antioxidant preservative in animal feeds. In farmed Atlantic salmon fillets, EQ residues are present, both as the parent compound and as EQ derivatives. One of the main EQ derivates in fish muscle is an ethoxyquin dimer (EQDM), and the potential toxicity of this metabolite is not known. The aim of this study was to evaluate the metabolism and potentially toxicological effects of EQDM. A 90-day subchronic exposure study with repeated dietary exposure to EQDM at 12.5 mg/kg of body weight per day was performed with male F344 rats. Hepatic Cyp1a1 mRNA was significantly reduced to <3% of the control in rats fed EQDM, and hepatic Cyp2b1 mRNA was increased to 192%. EQDM increased Gstpi1 mRNA expression to 144% that of the control, but the activity level of this phase II enzyme was reduced. Biomarkers of liver and kidney function did indicate adverse effects of EQDM when F344 rats were fed 12.5 mg/kg of body weight per day. The present study revealed that EQDM produces responses that are comparable to those produced by the parent compound (EQ) in terms of activating the same enzyme systems.     

Influence of the Strain History on TWIP Steel Deformation Mechanisms in the Deep-Drawing Process

A study of preferable deformation modes on strain path and strain level in a TWIP steel sheet was performed. Different strain paths were obtained by stretch forming of specimens with various shapes and tensile tests. TEM analysis was performed on samples cut from various locations in the deformed specimens, which had different strain paths and strain levels and the preferable deformation modes were identified. Stresses caused by various strain paths were considered and an analytical analysis performed to identify the preferable deformation modes for the case of single crystal. For a single crystal, in assumption of the absence of lattice rotation, the strain path and the level of accumulated equivalent strain define the preferable deformation mode. For a polycrystalline material, such analytical analysis is not possible due to the large number of grains and, therefore, numerical simulation was employed. For the polycrystalline material, the role of strain path diminishes due to the presence of a large number of grains with random orientations and the effect of accumulated strain becomes dominant. However, at small strains the strain path still defines the level of twinning activity. TEM analysis experimentally confirmed that various deformation modes lead to different deformation strengthening mechanisms.     

THE EFFECT OF ANTIOXIDANT ADDITIVE ON THE THERMOXIDATION STABILITY OF DISTILLATES FROM MEDIUM CRUDE OIL

Fractions 100-150, 150-200, 200-250°C were distilled from medium Iraqi crude oil. The thermo-oxidation stability experiments were carried out on original and inhibited (with Topanol 0) distillate fractions using the Alcor Jet Fuel Thermal Tester, over a temperature range 516-573 k. It was found that the antioxidant (Topanol 0) efficiency depends on the fractions composition and the oxidation temperature. Only 30 PPM of Topanol 0 stabilizes fraction 100-150°C to a considerable extent. Also, an inhibition effect is obtained in fraction 150-200°C but at a higher antioxidant concentration (90 PPM). Only, slight inhibition effect was observed in fraction 200-250°C at low oxidation temperature (below 551 K), while effect will be of no value at higher oxidation temperatures.     

Milk performance and glucose metabolism in dairy cows fed rumen-protected fat during mid lactation

Feeding rumen-protected fat (RPF) can improve energy supply for dairy cows but it affects glucose metabolism. Glucose availability is a precondition for high milk production in dairy cows. Therefore, this study investigated endocrine regulation of glucose homeostasis and hepatic gene expression related to glucose production because of RPF feeding in lactating cows. Eighteen Holstein dairy cows during second lactation were fed either a diet containing RPF (mainly C16:0 and C18:1; FD; n = 9) or a control diet based on corn starch (SD; n = 9) for 4 wk starting at 98 d in milk (DIM). Feed intake and milk yield were measured daily and milk composition once a week. Blood samples were taken weekly for analyses of plasma triglyceride, nonesterified fatty acids (NEFA), β-hydroxybutyrate, bilirubin, urea, lactate, glucose, insulin, and glucagon. At 124 DIM, an intravenous glucose tolerance test (GTT; 1 g/kg of BW^0.75) was performed after a 12-h period without food. Blood samples were taken before and 7, 14, 21, and 28 min after glucose administration, and plasma concentrations of glucose, insulin, and glucagon were measured. Glucose half-life as well as areas under the concentration curve for glucose, insulin, and glucagon were calculated. After slaughter at d 28 of treatment, liver samples were taken to measure mRNA abundance of pyruvate carboxylase, cytosolic phosphoenolpyruvate carboxykinase, glucose 6-phosphatase (G6Pase), and facilitative glucose transporter 2. Dry matter intake, but not energy and protein intake, was lower in FD than in SD. Milk yield during lactation decreased more in SD than in FD, and milk protein was lower in FD than in SD. Plasma concentrations of triglycerides and NEFA were higher in FD than in SD. Plasma insulin concentrations were lower and the glucagon:insulin ratios were higher in FD than in SD. Fasting glucose concentration before GTT was lower, and fasting glucagon concentrations tended to be higher in FD than in SD. In liver, fat content tended to be higher and G6Pase mRNA abundance was lower in FD than in SD. Lower hepatic G6Pase mRNA abundance was associated with reduced fasting plasma glucose concentrations, but the glucose-induced insulin response was not affected by RPF feeding. Hepatic G6Pase gene expression might be affected by DMI and might be involved in the regulation of glucose homeostasis in dairy cows, resulting in a lower hepatic glucose output after RPF feeding.     

RESIDUUM HYDROTREATING APPLICATION OF IH AND QUANTITATIVE CARBON-13 NMR SPECTROSCOPY FOR THE STUDY OF HYDROTREATED PRODUCTS

ABSTRACT

Bai-Hassan reduced crude (350^°C + ) was hydrotreated in fixed bed reactor with commercial Ni-Mo-alumina catalyst. H and quantitative C NMR are used to derive statistical average structure parameters of feedstock and hydrotreated products. The main aromatic hydrocarbons (of type C_ar,H + C_ar,CH₃ + C_ar,n + C_ar,I) of hydrotreated products decreases by temperature, (at mild conditions) particularly at lower space velocity. The severe operating conditions increases the main aromatic hydrocarbons. An approximate inverse correlation is observed between the behaviour of saturated hydrocarbons and the aromatics of type C_ar,H + C_ar,CH₃ + C_ar,n + C_ar,I during hydrotreating process. Higher temperatures show an increase in the percentage of alkyl aromatics of type C_ar,alkFurthermore, the severe operating conditions promotes the formation of the alkyl aromatics with H_α(ArCH₃) while it decreases the alkyl aromatic having H₈ and H₈ The kinetic study of napthenes formation indicates that this reactin is well correlated with a first-order kinetics. The apparent activation energy lpar;E rpar;, enthalpy lpar;? H rpar;and entropy lpar;? s?lpar; of activation are 23.630 KJ mol 18.390 kJ mol ^-1 and -225.95 J mol^-1 k^-1 respectively.     

RESIDUUM HYDROTREATING/APPLICATION OF LIQUID- SOLID CHROMATOGRAPHY FOR THE STUDY OF HYDROTREATED PRODUCTS.

Iraqi reduced crude (above 350^°C) was hydrotreated in a fixed-bed reactor with commercial Ni-Mo-alumina catalyst. Reaction temperature varied from 320 to 400^°C over liquid hourly space velocity ranging from 0.82 to 2.6 h^-1. Hydrogen pressure was kept constant throughout all the experiment at 6.1 MPa with hydrogen/ oil ratio about 30D NL/L. Asphaltenes were precipitated from the reduced crude and hydrotreated products with 15 parts of n-pentane (by volume) to 1 part of sample. Then, the deasphaltened products were fractionated by liquid- solid chromatography for saturates, aromatics and polar- aromatics separation. The kinetic study of aromatics and polar- aromatics hydrogenation indicates that these reactions are well correlated with a second-order kinetics. The rate constants of aromatics and polar-aromatics hydrogenation were calculated. Finally, the apparent activation energy (Ea), enthalpy of activation (▵H)^* and entropy (▵S)^* were calculated for hydrogenation of aromatics and polar-aromatics of reduced crude during hydrotreating.