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1.
肺癌在中国恶性肿瘤的发病率位居第一,随着低剂量薄层CT在肺癌筛查中的广泛应用,临床发现更多表现为非完全实性结节的肺腺癌,目前众多研究使CT影像学特征和肺腺癌病理的关系得到更进一步的认知,虽然CT能对部分非完全实性结节做出定性和定位诊断,但仍有部分非完全实性结节诊断困难,PET-CT结合了病灶的代谢信息和精确的定位信息,从而提高对肺部结节诊断的敏感性、特异性、准确性,综合多个文献PET-CT在非完全实性结节中的诊断分期价值较CT无明显提升,却在评估预后和制定合适手术方案上可以起到一定的作用,本文就PET-CT在SSN中的应用价值进行阐述。 相似文献
2.
Subdivision of equine Tf into H1 and H2 总被引:6,自引:0,他引:6
Subdivision of equine TfH into two variants, designated H1 (faster) and H2 (slower), has been accomplished by high voltage, thin layer polyacrylamide gel electrophoresis at pH 7.9. Transferrin H1 and H2 have been shown to be controlled by codominant alleles and gene frequencies of the Tf alleles have been determined in the Australian Thoroughbred, Standardbred. Quarter Horse and Arabian Horse breeds. 相似文献
3.
Expansion of the canine A blood group system 总被引:1,自引:0,他引:1
A detailed study of the canine A blood group system was undertaken, resulting in the expansion of this system into a three-factor, four-allelic one with the recognition of an additional subtype, a3. The serological and extensive family data supported the proposed genetic theory of four alleles with dominance with the order being Aa1, Aa2, Aa3 and A-. Gene frequencies of the alleles were determined in various breeds of dogs with frequencies in the general Brisbane population being 0.244 (Aa1), 0.042 (Aa2), 0.045 (Aa3) and 0.669 (A-). 相似文献
4.
ABSTRACT.
- 1 Patterns of vertical habitat use of ten species of cockroaches are examined. Three assemblages of cockroaches are recognized on the basis of morphology, foraging behaviour, foraging heights, and overlaps and breadths of vertical distributions.
- 2 Three apterous and brachypterous species occur near the ground and comprise one assemblage. They feed mainly on material in the leaf-litter.
- 3 Species that perch higher either migrate into the leaf-litter on a diel basis and feed on both leaf-litter and epiphyllic materials, or some are strictly arboreal and forage on algae, liverworts, lichens, spores, pollen and trichomes on the surfaces of leaves.
- 4 Trophic and behavioural correlations with perch height are described and the functions of perching are examined.
- 5 We conclude that studies of interactions among species are confounded by our lack of understanding of stage- and sex-specific interactions of coexisting species. A simplistic ‘species’approach to such interactions is inadequate because it does not recognize intraspecific variation.
5.
A. C. BELL 《The Annals of applied biology》1983,102(1):1-6
The life-history of leaf-curling plum aphid, Brachycaudus helichrysi was studied in Northern Ireland from 1977–1980. It was shown that the life cycle differed in several respects from those of geographically distinct populations, reported by other authors, especially with regard to the timing of egg hatch. Body length and antennal segment measurements of the adult stages on Prunus spinosa and Trifolium pratense correlated well with published dimensions for the species. Virological studies showed B. helichrysi to be capable of transmitting potato virus YC(AB) with a vector efficiency of 34%. This value is higher than previous estimates and enhances the significance of the species as a virus vector in potato crops early in the growing season. 相似文献
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Natal dispersal and genetic structure in a population of the European wild rabbit (Oryctolagus cuniculus) 总被引:1,自引:0,他引:1
A combination of behavioural observation, DNA fingerprinting, and allozyme analysis were used to examine natal dispersal in a wild rabbit population. Rabbits lived in territorial, warren based social groups. Over a 6-year period, significantly more male than female rabbits moved to a new social group before the start of their first breeding season. This pattern of female philopatry and male dispersal was reflected in the genetic structure of the population. DNA fingerprint band-sharing coefficients were significantly higher for females within the same group than for females between groups, while this was not the case for males. Wrighfs inbreeding coefficients were calculated from fingerprint band-sharing values and compared to those obtained from allozyme data. There was little correlation between the relative magnitudes of the F-statistics calculated using the two techniques for comparisons between different social groups. In contrast, two alternative methods for calculating FST from DNA fingerprints gave reasonably concordant values although those based on band-sharing were consistently lower than those calculated by an ‘allele’ frequency approach. A negative FIS value was obtained from allozyme data. Such excess heterozygosity within social groups is expected even under random mating given the social structure and sex-biased dispersal but it is argued that the possibility of behavioural avoidance of inbreeding should not be discounted in this species. Estimates of genetic differentiation obtained from allozyme and DNA fingerprint data agreed closely with reported estimates for the yellow-bellied marmot, a species with a very similar social structure to the European rabbit. 相似文献
10.
C. H. BELL 《Physiological Entomology》1981,6(3):231-239
ABSTRACT. When batches of about 100 moths of mixed age and sex were kept at 25°C, 65±5%r.h., few eggs were laid by Ephestia cautella, E.kuehniella, E.elutella and Corcyra cephalonica while they were exposed to light of 400-1000lx for up to 12h. Large numbers were laid soon after the light was switched off, however, and the yield during the first hour of darkness increased as the period previously spent in light increased from 1 to 18h. Plodia interpunctella , on the other hand, laid many eggs in light and the numbers laid subsequently during the first hour of darkness in the Slough stock were not influenced by the duration of the light exposure. In LD 12:12, the first four species laid most of their eggs during the scotophase, with E.cautella laying the largest number and E.elutella the smallest. E.cautella transferred from LD 12:12 to constant darkness showed a free-running circadian rhythm for at least three cycles, with most eggs laid near the time that was previously the first hour of darkness, but those transferred to constant light free-ran for only one cycle. 相似文献