首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
A. Szwed  M. Kosińska 《HOMO》2012,63(4):292-300
The main aim of the study was to assess the influence of biological maturity at birth on growth processes in the subsequent years and during puberty in girls. The material of this study comes from the outpatient clinic cards and cross-sectional research on girls from the province of Wielkopolska in Poland. It includes data of 527 girls. The influence of perinatal maturity on body weight in the later stages of ontogeny was determined with the use of the Kruskal–Wallis test and the Mann–Whitney U test. In order to determine the relationship between perinatal maturity and age at menarche, the survival analysis module was used.The results show a diverse influence of perinatal maturity on the values of body weight achieved in later years of life. The indicated predictive factors included both birth weight and gestational age. In the examined girls menarche occurred between the 10th year and the 17th year of life (X¯=12.87, s = 1.26; Me = 13 years). The comparison showed a significant variation in age at menarche depending on the length of pregnancy (log-rank χ22=27.068, p < 0.0001) and birth weight (log-rank χ22=23.241, p < 0.0001). There was no variation in maturation of the examined girls conditioned by the occurrence of intra-uterine growth retardation (log-rank χ22=2.046, p > 0.05). Remote prognoses as to the postnatal development of preterm-born children and/or children with low birth weight indicate adverse influence of these variables on age at menarche. Perinatal biological maturity of a newborn conditions the course of postnatal development.  相似文献   

9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
The branched structure properties of hyperbranched polysaccharides (TM3a and TM3b), extracted from sclerotia of Pleurotus tuber-regium, were studied by using laser light scattering and viscometry. The configurational shrinking factor (g) and viscometric shrinking factor (g′) of TM3a and TM3b were discussed, where curdlan and pullulan were taken as the linear references for derivation of g and g′. The dependences of g factor, g′ factor, and Flory factor (Φbranched) on weight average molecular weight (Mw) were established to be g = 1.07 × 102Mw-0.48±0.09, g′ = 3.63 × 101Mw-0.43±0.01, and Φbranched = 7.08 × 1020Mw0.39±0.1 for TM3a in 0.25 M LiCl/DMSO at 25 °C, when curdlan acted as the linear reference. A power law relationship g = 2.71 × 10?1g?0.61±0.1 for TM3a was found, and the exponent was approximately same to 0.60 established by Kurata et al. for polystyrene star molecules. The dependence of g factor on Mw for TM3b was found to be g = 1.99 × 102Mw-0.53±0.02, when pullulan was used as the linear reference. On the basis of Zimm–Stockmayer equation for tetrafunctional units, molecular weight of branching unit (M0) deduced from nonlinear curve fitting of g versus Mw was 8739 ± 564 g/mol and 3961 ± 1245 g/mol for TM3a and TM3b, respectively. The effect of different linear reference curves and polydispersity was discussed. This work gave valuable information on branched structure characterization and insights into the biosynthetic pathways of the hyperbranched polysaccharide from fungus.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号