排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
Summary The effect of negative and positive air ionisation on siliconized blood serotonin was studied in vitro. The experiments showed that within 10 min positive ionisation increased serotonin levels in total blood (+40%), plasma (+90%), erythrocytes (+50%) and thrombocytes (+200%). On the other hand, negative ionization (10 min) lowered the serotonin content of total blood (–30%), plasma (–42.5%), erythrocytes (–41.7%) and thrombocytes (–72.3%), thus confirming the Krueger Effect in vitro.This research was generously supported by a grant from the Joint Research Fund of the Hebrew University and Hadassah, and Dr. and Mrs.Leonard Appleby of Palmbeach, Florida.Acknowledgment: Our thanks are due to Mr.B. Shalita, Mrs.Zippora Adar and Mrs.Olga Fradkin for devoted technical assistance. 相似文献
2.
Optimization of Multi-Criteria Experiments with Fuzzy Results 总被引:1,自引:0,他引:1
Introduction To reach a best quality product, experiments and an op- timized design of experiments are required in an inte- grated quality management system. The best quality level of a manufacturing process or product is defined not only by one, but by m… 相似文献
3.
Jessica Pfeifer 《Studies in history and philosophy of science》2012,43(1):172-181
Mill appears to be committed to two incompatible accounts of laws. While he seems to defend a Humean account of laws similar to Ramsey’s and Lewis’s, he also appears to rely on modal notions to distinguish lawful relations from accidental regularities. This paper will show that Mill’s two accounts of laws are in fact equivalent. This equivalence results from a proper understanding of the necessity involved in laws and a proper understanding of systematization. This equivalence reveals the true source of the intimate connection between laws and systematization. Mill also provides an account of natural necessity that makes clear why experimentation is essential for gaining knowledge of laws. In contrast, Lewis’s account will be shown to have counterintuitive consequences regarding the relationship between laws and experimentation. Moreover, it will be shown that Mill’s views about inference result in a distinction between two modes of systematizing: subsumption and derivation. This distinction is overlooked in contemporary accounts of systematization, but Mill rightly notes that the metaphysical implications and epistemic role of these two modes are importantly different. 相似文献
4.
Pfeifer GP 《Nature genetics》2001,28(1):3-4
Certain human cancers and carcinogen-induced rodent tumors commonly contain Kras2 mutations. This activated form of ras has always been described as a dominant oncogene. A new study indicates that wildtype Kras2 has properties of a tumor suppressor gene and may have the capacity to reduce the transforming potential of oncogenically activated ras. 相似文献
5.
6.
Presley JF Ward TH Pfeifer AC Siggia ED Phair RD Lippincott-Schwartz J 《Nature》2002,417(6885):187-193
Cytosolic coat proteins that bind reversibly to membranes have a central function in membrane transport within the secretory pathway. One well-studied example is COPI or coatomer, a heptameric protein complex that is recruited to membranes by the GTP-binding protein Arf1. Assembly into an electron-dense coat then helps in budding off membrane to be transported between the endoplasmic reticulum (ER) and Golgi apparatus. Here we propose and corroborate a simple model for coatomer and Arf1 activity based on results analysing the distribution and lifetime of fluorescently labelled coatomer and Arf1 on Golgi membranes of living cells. We find that activated Arf1 brings coatomer to membranes. However, once associated with membranes, Arf1 and coatomer have different residence times: coatomer remains on membranes after Arf1-GTP has been hydrolysed and dissociated. Rapid membrane binding and dissociation of coatomer and Arf1 occur stochastically, even without vesicle budding. We propose that this continuous activity of coatomer and Arf1 generates kinetically stable membrane domains that are connected to the formation of COPI-containing transport intermediates. This role for Arf1/coatomer might provide a model for investigating the behaviour of other coat protein systems within cells. 相似文献
7.
8.
The effect of negative and positive air ionisation on siliconized blood serotonin was studied in vitro. The experiments showed that within 10 min positive ionisation increased serotonin levels in total blood (+40%), plasma (+90%), erythrocytes (+50%) and thrombocytes (+240%). On the other hand, negative ionization (10 min) lowered the serotonin content of total blood (-30%), plasma (-42.5%), erythrocytes (-41.7%) and thrombocytes (-72.3%), thus confirming the 'Krueger Effect' in vitro. 相似文献
9.
Gu TP Guo F Yang H Wu HP Xu GF Liu W Xie ZG Shi L He X Jin SG Iqbal K Shi YG Deng Z Szabó PE Pfeifer GP Li J Xu GL 《Nature》2011,477(7366):606-610
Sperm and eggs carry distinctive epigenetic modifications that are adjusted by reprogramming after fertilization. The paternal genome in a zygote undergoes active DNA demethylation before the first mitosis. The biological significance and mechanisms of this paternal epigenome remodelling have remained unclear. Here we report that, within mouse zygotes, oxidation of 5-methylcytosine (5mC) occurs on the paternal genome, changing 5mC into 5-hydroxymethylcytosine (5hmC). Furthermore, we demonstrate that the dioxygenase Tet3 (ref. 5) is enriched specifically in the male pronucleus. In Tet3-deficient zygotes from conditional knockout mice, paternal-genome conversion of 5mC into 5hmC fails to occur and the level of 5mC remains constant. Deficiency of Tet3 also impedes the demethylation process of the paternal Oct4 and Nanog genes and delays the subsequent activation of a paternally derived Oct4 transgene in early embryos. Female mice depleted of Tet3 in the germ line show severely reduced fecundity and their heterozygous mutant offspring lacking maternal Tet3 suffer an increased incidence of developmental failure. Oocytes lacking Tet3 also seem to have a reduced ability to reprogram the injected nuclei from somatic cells. Therefore, Tet3-mediated DNA hydroxylation is involved in epigenetic reprogramming of the zygotic paternal DNA following natural fertilization and may also contribute to somatic cell nuclear reprogramming during animal cloning. 相似文献
10.
A. Klara Pfeifer E. Sz. Vizi Eva Satory Eva Galambos 《Cellular and molecular life sciences : CMLS》1963,19(9):482-483
Zusammenfassung Sieben Tage nach Adrenalektomie ist der 5-HT-Gehalt des Rattengehirns vermindert, während der NA-Gehalt unverändert bleibt. Chronische Hydrocortisonbehandlung restituiert, DOCA-Behandlung bleibt wirkungslos. Nach 5-HTP-Behandlung steigt der 5-HT-Gehalt auch im Gehirn der adrenalektomierten Tiere. 相似文献