Occurrence of mutagenic/carcinogenic heterocyclic amines in meat and fish products, including pan residues, prepared under domestic conditions

Some typical Swedish meat and fish products, e.g. bacon, beefburgers, meatballs, Baltic herring, salmon, smoked fish, black pudding and sausages, and their corresponding pan residues, were analysed by HPLC for their content of mutagenic/carcinogenic heterocyclic amines (HAs). The products were cooked using recommended domestic cooking conditions concerning temperature, time and frying equipment. The amount of HAs was low in most products, though the amount was higher in the pan residues, especially in the pan residue from the frying of Falun sausage, which contained 18.5 ng HAs/g cooked product. Mostly MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]-quinoxaline) and 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]-quinoxaline) were found, being 0.03-2.8 ng MeIQx/g and n.d.-3.4 ng 4,8-DiMeIQx/g cooked product in the food products and 0.05-7.3 ng MeIQx/g and n.d.-2.8 ng 4,8-DiMeIQx/g cooked product in the pan residues. High levels of IQ (2-amino-3-methylimidazo[4,5-f]quinoline), 10.5 ng/g, were only found in well-done bacon and a correlation was seen between fat content and IQ formation. Low levels of MeIQ (2-amino-3,4-dimethylimidazo[4,5-f]quinoline) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) were found in the foods.     

载金炭常压解吸化学提金工艺及其应用

主要介绍了载金炭常压解吸化学提金工艺和应用效果。载金炭经预处理后,在105℃、常压解吸金,解吸责液经化学沉淀生成海绵金。该工艺的应用实践表明,金解吸率可达99％以上,解吸贫炭金品位在80g／t以下。     

Determination of the initial stage of fat auto-oxidation in dry dairy products by ultraviolet spectrophotometry

Studied were the values of the conjugated dienes using ultraviolet spectrophotometry of fats contained in the dry dairy products produced in this country, such as powdered milk for children, Vitalakt 1, Bébé 1, and Biolakton in the first months of storage. It was found that the extinction maximum values characteristic of the conjugated dienes for the fats of all studied dry milk products were at 227 nm. The juxtaposition of changes taking place with conjugated dienes and peroxide numbers of the fats during storage revealed the greater stability of conjugated dienes in comparison with the hydroperoxides.     

Consumption of meat, animal products, protein, and fat and risk of breast cancer: a prospective cohort study in New York

Epidemiologic studies have focused on the association between diet and breast cancer with conflicting results. Whereas a majority of case-control studies indicate a role for the intake of total fat and saturated fat, most prospective cohort studies either are negative or indicate very modest associations. Only a few authors have examined the role of meat intake in relation to breast cancer risk. The aim of this study was to examine the relation between risk of breast cancer and dietary intake of meat, animal products, fat, and protein. Between 1985 and 1991, we recruited 14,291 New York City women in a prospective cohort study of endogenous hormones, diet, and cancer in which they reported on their recent diet using a food frequency questionnaire self-administered at enrollment. From the cohort, 180 invasive breast cancer cases diagnosed before December 1990 and five times as many controls, individually matched by age, calendar time at enrollment, menopausal status, and, if premenopausal, phase of menstrual cycle, were included in a nested case-control study. There was an evident increase in the relative risk (RR) of breast cancer for increasing consumption of meat. Women in the upper quintile of meat consumption, as compared with the lowest quintile, had an energy-adjusted RR of 1.87 (95% confidence interval = 1.09-3.21). There was a modest RR increase in the upper quintile of total and saturated fat and no apparent association for other types of fat, protein, dairy products, poultry, or fish.(ABSTRACT TRUNCATED AT 250 WORDS)     

Equilibrium vapour pressure of mercury from dental amalgam under loading conditions

Earlier studies have failed to establish a consensus on the amount of mercury vapour released from dental amalgam restorations. The purpose of this study was to accurately and quantitatively measure the equilibrium mercury vapour pressure from dental amalgam. The vapour pressure was measured using a quartz crystal microbalance as a function of the load from 0-5.4 MPa. Auger spectra were collected of the as-formed and argon ion sputter cleaned dental amalgam surface. For the as-formed surface the mercury vapour density is zero with no load and increases to 0.6 microg m(-3) at 5.4 M Pa. Following cleaning the mercury, vapour density increased to a maximum value of 15 microg m(-3). The Auger spectra of the as-formed surfaces were dominated by features associated with carbon and oxygen. These spectral results in concert with the mercury vapour density measurements indicate that the oxide film on the as-formed surfaces inhibited the release of mercury vapour. The results of this experiment provide an upper limit for the amount of mercury vapour released by dental amalgams. Under conditions simulating the oral cavity this value would be reduced by oxides that form on the surface of dental amalgam restorations.     

Sulfidation under atmospheric conditions of Cu-Ni,Cu-Sn,and Cu-Zn binary and Cu-Ni-Sn and Cu-Ni-Zn ternary systems

The corrosion susceptibility of binary and ternary alloys can be assessed by controlled exposures to corrosive environments of samples selected from different regions of the phase diagram. To conduct such studies, we have prepared 24 high purity alloys from the Cu-Ni, Cu-Sn, and Cu-Zn binary and Cu-Ni-Sn and Cu-Ni-Zn ternary systems. Samples of these alloys were then exposed for varying periods to atmospherically realistic concentrations of hydrogen sulfide in humidified air. The resulting sulfurization of the samples is presented in a series of chromatic plots developed as part of this research. The ability of binary alloying metals to retard the sulfidation of copper follows the order Zn > Ni > Sn. The Cu-Ni-Zn ternary alloys are more resistant to sulfidation than Cu-Ni-Sn alloys for the same extent of solid solution alloying; in fact, alloys in the Cu-Ni-Zn system with ≤70 pct copper proved to be extremely resistant to sulfidation. In both ternary systems, the relative performance of the alloys was different at different exposure periods, a result that emphasizes the importance of monitoring corrosion throughout realistic exposures if the results are to be used in the selection of materials for field applications.     

Sulfidation under atmospheric conditions of Cu-Ni,Cu-Sn,and Cu-Zn binary and Cu-Ni-Sn and Cu-Ni-Zn ternary systems

The corrosion susceptibility of binary and ternary alloys can be assessed by controlled exposures to corrosive environments of samples selected from different regions of the phase diagram. To conduct such studies, we have prepared 24 high purity alloys from the Cu-Ni, Cu-Sn, and Cu-Zn binary and Cu-Ni-Sn and Cu-Ni-Zn ternary systems. Samples of these alloys were then exposed for varying periods to atmospherically realistic concentrations of hydrogen sulfide in humidified air. The resulting sulfurization of the samples is presented in a series of chromatic plots developed as part of this research. The ability of binary alloying metals to retard the sulfidation of copper follows the order Zn > Ni > Sn. The Cu-Ni-Zn ternary alloys are more resistant to sulfidation than Cu-Ni-Sn alloys for the same extent of solid solution alloying; in fact, alloys in the Cu-Ni-Zn system with ≤70 pct copper proved to be extremely resistant to sulfidation. In both ternary systems, the relative performance of the alloys was different at different exposure periods, a result that emphasizes the importance of monitoring corrosion throughout realistic exposures if the results are to be used in the selection of materials for field applications.     

Protein, amino acid contents and protein efficiency ratio of Egyptian buffalo meat under different biological conditions

The effect of age, sex, season and cut variations on the protein, amino acids contents and protein efficiency ratio (P.E.R.) of Egyptian Buffalo meat was studied in 128 samples. Statistical analysis for the data obtained showed significant difference at 0.01 level for protein in relation to cut (abdomen and thigh, respectively), male in relation to season and dry season in relation to sex. There is also significant difference at 0.05 level in case of green season in relation to sex. Protein shows a significant difference at 0.1 level due to sex variation. There is a difference in the amino acids content of young and old animals during dry season in both cuts. Young animals show higher values than old ones in most of the amino acids investigated. There is also an obvious difference in the amino acids during green season between male and female animals, and also between both cuts. P.E.R. of Egyptian Buffalo meat as 10% protein level ranges between 3.02 and 2.35 according to seasonal, cut and age variations.     

Materials science under extreme conditions of pressure and strain rate

Solid-state dynamics experiments at very high pressures and strain rates are becoming possible with high-power laser facilities, albeit over brief intervals of time and spatially small scales. To achieve extreme pressures in the solid state requires that the sample be kept cool, with T _sample<T _melt. To this end, a shockless, plasma-piston “drive” has been developed on the Omega laser, and a staged shock drive was demonstrated on the Nova laser. To characterize the drive, velocity interferometer measurements allow the high pressures of 10 to 200 GPa (0.1 to 2 Mbar) and strain rates of 10⁶ to 10⁸ s⁻¹ to be determined. Solid-state strength in the sample is inferred at these high pressures using the Rayleigh-Taylor (RT) instability as a “diagnostic.” Lattice response and phase can be inferred for single-crystal samples from time-resolved X-ray diffraction. Temperature and compression in polycrystalline samples can be deduced from extended X-ray absorption fine-structure (EXAFS) measurements. Deformation mechanisms and residual melt depth can be identified by examining recovered samples. We will briefly review this new area of laser-based materials-dynamics research, then present a path forward for carrying these solid-state experiments to much higher pressures, P>10³ GPa (10 Mbar), on the National Ignition Facility (NIF) laser at Lawrence Livermore National Laboratory. This article is based on an invited presentation given in the symposium “Dynamic Deformation: Constitutive Modeling, Grain Size, and Other Effects: In Honor of Prof. Ronald W. Armstrong,” March 2–6, 2003, at the 2003 TMS/ASM Annual Meeting, San Diego, California, under the auspices of the TMS/ASM Joint Mechanical Behavior of Materials Committee.     

The detection of chicken meat in meat products by means of the anserine/carnosine ratio

10 patients with their first AMI were studied within the first 48 hours and again after 3 weeks. Central and peripheral haemodynamics (CI, SV, SW, TPR) were examined, including indices of contractility (dp/dtmax) and wall stiffness (deltaP/deltaV, relation deltaP/deltaV to P) of the left ventricle. In the early phase CI and SW, as well as LV dp/dtmax were depressed in accordance with symptoms of LV failure. deltaP/deltaV was increased. Elevation of LVEDP correlated well with ventricular gallop rhythm, but less consistently with LV functional disturbance. During convalescence CI increased uniformly, both in digitalized and non-digitalized individuals. In contrast heart rate, aortic pressure, LVEDP and dp/dtmax remained unchanged. The increase of CI, SV and SW was accompanied by a fall of TPR and deltaP/deltaV. LV wall stiffness was still elevated above normal after 3 weeks. The improvement of cardiac pumping during infarct convalescence may have been effected through a fall of TPR and LV wall stiffness. Recovery of depressed contractile performance was generally not observed, and does therefore not seem to contribute to recuperation.     

Identification of bifidobacteria from dairy products and evaluation of a microplate hybridization method

Sixteen strains of Bifidobacterium isolated from 15 dairy products such as yogurt, cultured milk, butter and cheese were characterized on the basis of phenotypic characteristics and DNA similarities were examined by a microplate hybridization method. Three of the strains were identified as Bifidodobacterium longum, one strain was identified as Bifidobacterium bifidm, and one strain was assigned to the species Bifidobacterium breve on the basis of phenotypic characteristics, and this identification was confirmed by the analysis of DNA similarities. The remaining 11 strains could not be identified by examining their phenotypic characteristics and, contrary to the product label information, these strains were identified as Bifudidobacterium animalis on the basis of DNA similarities. The applicability of the colorimetric hybridization method in micro dilution wells to genetic identification of Bifidobacterium species was also studied.     

Molecular identification and cluster analysis of homofermentative thermophilic lactobacilli isolated from dairy products

Twenty-five strains of thermophilic lactobacilli isolated from yoghurt and from semi-hard and hard cheeses (in parallel with nine type or reference strains) were identified and grouped according to their genetic relatedness. Strains were identified by sugar fermentation patterns using the "API 50 CHL" galleries, by species-specific DNA probes in dot-blot hybridization experiments, by amplification and restriction analysis of the 16S rRNA gene (ARDRA) and by polymerase chain reaction (PCR) using species-specific oligonucleotide primers. Strains were classified as Lactobacillus delbrueckii subsp. lactis and subsp. bulgaricus, L. helveticus, and L. acidophilus. Strains which were atypical by sugar fermentation patterns were also identified. Most of the strains could not be grouped using carbohydrate fermentation profiles. PCR fingerprinting was used to identify DNA profiles for the 25 lactobacilli. Experimentally obtained PCR profiles enabled discrimination of all strains, which were grouped according to the similarities in their combined patterns. In general, the clustering of the strains corresponded well with species delineation obtained by molecular identification. The dendrogram of genetic relatedness enabled the unambiguous identification of most of the strains which were shown to be atypical by the sugar fermentation profile, except for a discrepancy in one L. delbrueckii subsp. lactis strain and one atypical Lactobacillus sp. strain.     

Effect of atmospheric pressure on physical parameters of steels and solidification conditions during PESR process:a review

The pressurized electroslag remelting (PESR) process has a remarkable impact on manufacturing high nitrogen steels,which can alter the physical parameters of st...     

Fatigue crack growth rates in a pressure vessel steel under various conditions of loading and the environment

Corrosion fatigue (CF) tests have been carried out on SA508 Cl 3 pressure vessel steel, in simulated P.W.R. environments. The test variables investigated included air and P.W.R. water environments, frequency variation over the range 1 Hz to 10 Hz, transverse and longitudinal crack growth directions, temperatures of 20 °C and 50 °C, andR-ratios of 0.2 and 0.7. It was found that decreasing the test frequency increased fatigue crack growth rates (FCGR) in P.W.R. environments, P.W.R. environment testing gave enhanced crack growth(vs air tests), FCGRs were greater for cracks growing in the longitudinal direction, slight increases in temperature gave noticeable accelerations in FCGR, and several air tests gave FCGR greater than those predicted by the existing ASME codes. Fractographic evidence indicates that FCGRs were accelerated by a hydrogen embrittlement mechanism. The presence of elongated MnS inclusions aided both mechanical fatigue and hydrogen embrittlement processes, thus producing synergistically fast FCGRs. Both anodic dissolution and hydrogen embrittlement mechanisms have been proposed for the environmental enhancement of crack growth rates. Electrochemical potential measurements and potentiostatic tests have shown that sample isolation of the test specimens from the clevises in the apparatus is not essential during low temperature corrosion fatigue testing. P. D. HICKS, formerly Graduate Student at The University of The Witwatersrand, South Africa