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排序方式: 共有293条查询结果,搜索用时 15 毫秒
281.
From 1998 to 2001, 216 ingredients intended for incorporation into chicken feed, which included groundnut cake, maize, millets, rice bran, sorghum, soybean, sunflower, and mixed feeds, were assayed for aflatoxins and ochratoxin A contamination using an indirect competitive enzyme-linked immunosorbent assay. Thirty-eight percent of the samples were contaminated with aflatoxins and 6% with ochratoxin A. The incidence scores of aflatoxin contamination in excess of 10 microg/kg were 41 of 95 for maize, 18 of 30 for mixed feeds, 10 of 37 for groundnut, 6 of 29 for sorghum, 5 of 10 for sunflower, 3 of 14 for rice bran, and 1 of 8 for millet. Ochratoxin A contamination, in excess of 10 microg/kg, was found in 9 of 29 sorghum samples, 1 of 27 groundnut samples, 1 of 14 rice bran samples, 1 of 10 sunflower samples, and 2 of 8 millet samples. Ochratoxin A was not found in maize and mixed feeds. None of the three soybean samples contained ochratoxin A. This is the first report, to our knowledge, of co-occurrence of aflatoxins and ochratoxin A in Indian poultry feeds. The results confirm the importance of analysis of ingredients before incorporating them into mixed feeds. 相似文献
282.
Adey NB Lei M Howard MT Jensen JD Mayo DA Butel DL Coffin SC Moyer TC Slade DE Spute MK Hancock AM Eisenhoffer GT Dalley BK McNeely MR 《Analytical chemistry》2002,74(24):6413-6417
A microarray hybridization system that allows mixing in volumes comparable to those used by glass coverslips is presented. This system is composed of a disposable flexible lid that binds to 1 in. x 3 in. glass slides via an adhesive gasket, forming a uniform 25-microm-thick hybridization chamber. This chamber rests on a base unit for temperature control. The lid contains two air-driven bladders that continuously mix the hybridization fluid. Mixing enhances sensitivity from a typical microarray experiment 2-3-fold. Mixing is particularly effective at high spotted probe and low labeled target concentrations and overcoming local target depletion that occurs when homologous probes are spotted in close proximity. Mixing appears to be compatible with most hybridization conditions; however, mix versus no-mix control experiments should be performed. Also covered are a number of microfluidic issues related to manufacturing, filling, mixing, and packaging. 相似文献
283.
M. J. Fogarty R. K. Mayo L. O'Brien F. M. Serchuk A. A. Rosenberg 《Reliability Engineering & System Safety》1996,54(2-3)
The assessment and management of exploited fish and invertebrate populations is subject to several types of uncertainty. This uncertainty translates into risk to the population in the development and implementation of fishery management advice. Here, we define risk as the probability that exploitation rates will exceed a threshold level where long term sustainability of the stock is threatened. We distinguish among several sources of error or uncertainty due to (a) stochasticity in demographic rates and processes, particularly in survival rates during the early fife stages; (b) measurement error resulting from sampling variation in the determination of population parameters or in model estimation; and (c) the lack of complete information on population and ecosystem dynamics. The first represents a form of aleatory uncertainty while the latter two factors represent forms of epistemic uncertainty. To illustrate these points, we evaluate the recent status of the Georges Bank cod stock in a risk assessment framework. Short term stochastic projections are made accounting for uncertainty in population size and for random variability in the number of young surviving to enter the fishery. We show that recent declines in this cod stock can be attributed to exploitation rates that have substantially exceeded sustainable levels. 相似文献
284.
Ovarian remnants occur after a portion of ovarian tissue is left behind unintentionally after oophorectomy. The ovarian remnant may be functional and cystic, producing pelvic pain and, in some patients, extrinsic compression of the distal ureter. Ovarian remnants frequently are associated with adhesions from previous pelvic surgery for endometriosis or pelvic inflammatory disease. Ovarian remnants also may be included within pelvic peritoneal inclusion cysts. In this retrospective study, the sonographic features of ovarian remnants in 10 patients with surgical proof or clinical follow-up data are described. Most ovarian remnants were simple cysts (seven of 10), three had multiple septations, and six had a rim of presumably ovarian tissue with arterial and venous flow. Three patients with ovarian remnant masses that were aspirated had symptomatic relief without recurrence. In one patient, guided aspiration was unsuccessful, probably owing to the presence of organized hemorrhage within the mass. Extrinsic compression of the distal ureter was observed in one patient, who was treated with gonadotropin releasing hormone agonist (Lupron). The sonographic findings of a completely cystic or multiseptated pelvic mass with a rim of vascularized solid tissue in a postoophorectomy patient, although such cases are rare, suggest the diagnosis of an ovarian remnant. If the diagnosis can be established with a high degree of certainty, sonographically guided aspiration may be attempted in an effort to provide symptomatic relief. Otherwise, sonography is useful in serial assessment of these masses in patients receiving medical treatment. 相似文献
285.
Ss were presented with 1 block of univalent information about a person, recorded their impression of him, and were then presented with a 2nd block of information opposite in valence to the 1st, about the same person. 3 independent variables were used: cognitive complexity, sex, and order of presentation of the information. As was hypothesized, cognitive complexity was significantly related to susceptibility to recency effects after hearing the last block of information: Ss high in complexity changed somewhat in the direction of the most recent information, arriving at an ambivalent final impression, while lows changed markedly, arriving at an extremely univalent final impression. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
286.
We sought to determine the relationship between an isolated choroid plexus cyst diagnosed antenatally and fetal aneuploidy in an unselected population at a district general hospital. Over a 5-year period all women attending for a detailed anomaly scan at 18-20 weeks' gestation were screened for evidence of a fetal choroid plexus cyst. All cases of choroid plexus cyst were recorded prospectively. The size, position and number of the cysts were noted and associated abnormalities seen on ultrasound were also recorded. Cases of choroid plexus cyst associated with fetal aneuploidy were noted. A total of 13,690 women were screened, and 84 cases of choroid plexus cyst were identified (0.6%). Of these, 41% underwent prenatal karyotyping by amniocentesis; 78 of 84 cases (93%) were isolated. Six had other markers for aneuploidy, and three of these fetuses had trisomy 18. All cases of isolated choroid plexus cyst resulted in chromosomally normal neonates. This was confirmed by either normal antenatal karyotype or postnatal examination by the pediatricians. The size, position and number of cysts did not appear to influence the risk of aneuploidy. We conclude that the risk of aneuploidy for a case of isolated choroid plexus cyst in an unselected population appears to be very low, and in this series was 0%. In this setting, we suggest detailed ultrasound examination is essential, rather than routine karyotyping. 相似文献
287.
288.
Heritability is well known to be a poor indicator of genetical variation in fitness. We show here that it is also an inadequate measure of genetical variation in fecundity. 相似文献
289.
The aim of this work was the genetic characterization at the strain level of 39 presumed Geotrichum candidum isolates isolated throughout the artisanal manufacturing and ripening of Armada cheese and tentatively identified at genus and/or species level by phenotypic characteristics. The molecular identification of the strains included among others the amplification and sequencing of the D1/D2 domains of the 26S rRNA gene. A restriction fragment length polymorphism (RFLP) analysis with the ITS1-5.8S-ITS2 PCR amplicons and a randomly amplified polymorphic DNA (RAPD) analysis with five different primers were carried out. The bands pattern profile obtained through RFLP by enzymatic restriction with HinfI was the same for all the strains studied, which confirmed the classification of the strains at species level. A RAPD-PCR analysis with three different primers was applied to assess the intraspecific diversity, in this way 16 band profiles were obtained for the 39 strains studied by the combined use of primers Ari1 and Omt1. This study contributes to know the occurrence and genotypic biodiversity of G. candidum in Armada cheese. 相似文献
290.
Flórez AB Danielsen M Korhonen J Zycka J von Wright A Bardowski J Mayo B 《The Journal of dairy research》2007,74(3):262-268
In order to establish cut-off values for Lactococcus lactis to six antibiotics to distinguish susceptible and intrinsically resistant strains from those having acquired resistances, the minimum inhibitory concentration (MIC) of tetracycline, erythromycin, clindamycin, streptomycin, chloramphenicol and vancomycin was determined in 93 different Lc. lactis strains using the Etest. These bacterial strains were originally isolated from dairy and animal sources in widely separated geographical locations. Cut-offs were defined on the basis of the distribution of the MICs frequency of the studied antibiotics, which in the absence of acquired determinants should approach to a normal statistical distribution. In general, the new cut-off values proposed in this study are higher than previously defined (European Commission, 2005. The EFSA Journal 223, 1-12). Based on these new values, all the strains tested were susceptible to erythromycin, chloramphenicol and vancomycin, and 79 susceptible to all six antibiotics. However, 11 strains (around 12%) were considered resistant to tetracycline (six of which had been identified after screening of a large collection of lactococci strains for tetracycline resistance) and five (5.4%) resistant to streptomycin. Of these, two fish isolates proved to be resistance to both tetracycline and streptomycin. From the tetracycline resistant strains, tet(M) and mosaic tet(L/S) genes were amplified by PCR, demonstrating they harboured acquired antibiotic resistance determinants. 相似文献