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排序方式: 共有548条查询结果,搜索用时 15 毫秒
1.
2 10-year marriage cohorts from 2 surveys of married women in Melbourne were compared on their timing of the 1st and 2nd births. The results showed that women who were married in the early 1970s were much more likely to delay their first birth until about the 3rd or 4th year of marriage compared with women who married in the 1960s. This tendency to delay the 1st birth was probably aided by effective contraception, as it coincided with widespread use of the oral contraceptive. There was no difference in the timing of the 2nd birth in relation th the 1st birth between the 2 marriage cohorts. Women who delayed childbearing also preferred smaller families. Indeed, the increase in the % of women delaying childbearing appears to be synonymous with the trend toward the two-child family. Altough the number of married women in the labor force increased significantly from the early to the later cohort, a desire to work was not usually cited as the reason for delaying childbearing. Rather, economic reasons were most frequently mentioned for delaying childbearing. 相似文献
2.
We simulated gas transport due to cardiogenic oscillations (CO) using a model developed to quantify the gas mixing due to high-frequency ventilation (16). The basic components of the model are 1) gas mixing by augmented transport, 2) symmetrical lung morphometry, and 3) a Lagrangian (moving) reference frame. The theoretical predictions of the model are in general agreement with published experimental studies that have examined the effect of CO on the nitrogen concentration obtained by intrapulmonary gas sampling and the effect of CO on regional and total anatomical dead space. Further, the model predicts that augmentation of gas transport due to CO is less, nearer to the alveolar regions of the lung, and that the effect of CO during normal tidal breathing is negligible, but that CO may contribute up to approximately 10% of the alveolar ventilation in patients with severe hypoventilation. The agreement between experimental and theoretical results suggests that it may not be necessary to invoke gas transport mechanisms specific to an asymmetrical bronchial tree to explain the major proportion of gas transport due to CO. 相似文献
3.
A patient with renal failure developed hypermagnesaemia, with confusion, drowsiness, and dysarthria. Nevertheless, the dietary magnesium content was low, and investigation showed actual intracellular depletion of magnesium. The cause of this state is not known, though it is presumably connected with a failure to maintain the normal concentration gradient of magnesium across the cell wall. The clinical state and the serum magnesium level returned to normal after treatment with calcium gluconate. 相似文献
4.
Boon Seng Ooi Beatrice T. M. Chen Charles C. S. Toh Oon Teik Khoo 《BMJ (Clinical research ed.)》1970,3(5725):744-746
Of 127 hypertensive patients aged 12 to 40 investigated by intravenous pyelography, abdominal aortography, and renal biopsy an underlying cause was found in 57%. The proportion with secondary hypertension was higher in young patients and in those with severe hypertension. Primary arteritis of the aorta was an important cause of renovascular hypertension in an Asian population. 相似文献
5.
Nielsen J; Peixoto AA; Piccin A; Costa R; Kyriacou CP; Chalmers D 《Molecular biology and evolution》1994,11(6):839-853
The region of the clock gene period (per) that encodes a repetitive tract
of threonine-glycine (Thr-Gly) pairs has been compared between Dipteran
species both within and outside the Drosophilidae. All the non-
Drosophilidae sequences in this region are short and present a remarkably
stable picture compared to the Drosophilidae, in which the region is much
larger and extremely variable, both in size and composition. The
accelerated evolution in the repetitive region of the Drosophilidae appears
to be mainly due to an expansion of two ancestral repeats, one encoding a
Thr-Gly dipeptide and the other a pentapeptide rich in serine, glycine, and
asparagine or threonine. In some drosophilids the expansion involves a
duplication of the pentapeptide sequence, but in Drosophila pseudoobscura
both the dipeptide and the pentapeptide repeats are present in larger
numbers. In the nondrosophilids, however, the pentapeptide sequence is
represented by one copy and the dipeptide by two copies. These observations
fulfill some of the predictions of recent theoretical models that have
simulated the evolution of repetitive sequences.
相似文献
6.
Noriko Takahashi Katsuyoshi Masuda Kenji Hiraki Kazuo Yoshihara Hung-Hsiang Huang Kay-Hooi Khoo Koichi Kato 《European journal of biochemistry》2003,270(12):2627-2632
To determine the glycoforms of squid rhodopsin, N-glycans were released by glycoamidase A digestion, reductively aminated with 2-aminopyridine, and then subjected to 2D HPLC analysis [Takahashi, N., Nakagawa, H., Fujikawa, K., Kawamura, Y. & Tomiya, N. (1995) Anal. Biochem.226, 139-146]. The major glycans of squid rhodopsin were shown to possess the alpha1-3 and alpha1-6 difucosylated innermost GlcNAc residue found in glycoproteins produced by insects and helminths. By combined use of 2D HPLC, electrospray ionization-mass spectrometry and permethylation and gas chromatography-electron ionization mass spectrometry analyses, it was revealed that most (85%) of the N-glycans exhibit the novel structure Manalpha1-6(Manalpha1-3)Manbeta1-4GlcNAcbeta1-4(Galbeta1-4Fucalpha1-6)(Fucalpha1-3)GlcNAc. 相似文献
7.
Khoo Kay-Hooi; Chatterjee Delphi; Caulfield John P.; Morris Howard R.; Dell Anne 《Glycobiology》1997,7(5):653-661
The granulomatous pathology in human intestinal schistosomiasisis induced primarily by the egg antigens of schistosome, a parasitictrematode. Glycolipids and glycoproteins were extracted fromthe eggs of the two major species which infect human, Schistosomamansoni and Schistosoma japonicum, for structural characterizationbased on highly sensitive mass spectrometric analysis coupledwith chemical derivatization. Here, we demonstrate that a seriesof uniquely multifucosylated glycosphingolipids constitute themajor egg glycolipids of S.mansoni but not of S.japonicum. TheS.mansoni glycosphingolipids were found to be extended by varyingnumbers of an unusual repeating unit, 相似文献
8.
Photosynthetic enhancement studies performed at 619 nm (excitation of Systems I and II) and at 446 nm (mainly excitation of System I) revealed an 18% photosynthetic enhancement simultaneously with a 31% reduction in glycolate excretion. This observation supports the hypothesis that some glycolate may be consumed in an oxidation process associated with System I when System II is poorly excited and the supply of electrons from the water splitting process of photosynthesis is low. 相似文献
9.
J C Khoo D Steinberg E Y Lee 《Biochemical and biophysical research communications》1978,80(2):418-423
Diglyceride lipase of chicken adipose tissue was found to be activated by cyclic AMP-dependent protein kinase to the same extent as hormone-sensitive triglyceride lipase (3-to 10-fold) when lipase assays were carried out in buffers of low ionic strength. Sodium phosphate (50 mM) or sodium chloride (100 mM) preferentially enhanced the basal (nonactivated) form of diglyceride lipase, which minimized the apparent activation by protein kinase. The activated diglyceride lipase was readily deactivated by a pure protein phosphatase from bovine heart (MW 35,000) and the deactivated enzyme was then reactivated by protein kinase. 相似文献
10.
The Fps/Fes protein-tyrosine kinase promotes angiogenesis in transgenic mice. 总被引:8,自引:3,他引:8 下载免费PDF全文
P Greer J Haigh G Mbamalu W Khoo A Bernstein T Pawson 《Molecular and cellular biology》1994,14(10):6755-6763