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111.
112.
D. J. Finney 《Biometrical journal. Biometrische Zeitschrift》1981,23(3):305-307
HORN (1979) queried the recommended ratio where p is the number of treated groups to be compared with a control and n and n0 are the sizes of the treated samples and of the control. The rule was originally stated for maximizing the precision of estimates, and not for optimizing any aspect of significance tests. Although in applied statistics, significance tests are usually of far less importance, it is interesting (but scarcely surprising) that the same rule optimizes power and one or two related characteristics. 相似文献
113.
The impact of the microbiota on the immune status of its host is a source of intense research and publicity. In comparison, the effect of arthropod microbiota on vector-borne infectious diseases has received little attention. A better understanding of the vector microbiota in relation to mammalian host immune responses is vital, as it can lead to strategies that affect transmission and improve vaccine design in a field of research where few vaccines exist and effective treatment is rare. Recent demonstrations of how microbiota decrease pathogen development in arthropods, and thus alter vector permissiveness to vector-borne diseases (VBDs), have led to renewed interest. However, hypotheses on the interactions between the arthropod-derived microbiota and the mammalian hosts have yet to be addressed. Advances in DNA sequencing technology, increased yield and falling costs, mean that these studies are now feasible for many microbiologists and entomologists. Here, we distill current knowledge and put forward key questions and experimental designs to shed light on this burgeoning research topic. 相似文献
114.
Janet L. Wolford Yasmin Chishti Qiaoling Jin Jesse Ward Liaohai Chen Stefan Vogt Lydia Finney 《PloS one》2010,5(8)
The pluripotency of human embryonic stem cells (hESCs) is important to investigations of early development and to cell replacement therapy, but the mechanism behind pluripotency is incompletely understood. Zinc has been shown to play a key role in differentiation of non-pluripotent cell types, but here its role in hESCs is directly examined. By mapping the distribution of metals in hESCs at high resolution by x-ray fluorescence microprobe (XFM) and by analyzing subcellular metal content, we have found evidence that loss of pluripotency is directly correlated with an increase in nuclear zinc. Zinc elevation not only redefines our understanding of the mechanisms that support pluripotency, but also may act as a biomarker and an intervention point for stem cell differentiation. 相似文献
115.
Lopez M Kurkal-Siebert V Dunn RV Tehei M Finney JL Smith JC Daniel RM 《Biophysical journal》2010,99(8):L62-L64
Water is widely assumed to be essential for life, although the exact molecular basis of this requirement is unclear. Water facilitates protein motions, and although enzyme activity has been demonstrated at low hydrations in organic solvents, such nonaqueous solvents may allow the necessary motions for catalysis. To examine enzyme function in the absence of solvation and bypass diffusional constraints we have tested the ability of an enzyme, pig liver esterase, to catalyze alcoholysis as an anhydrous powder, in a reaction system of defined water content and where the substrates and products are gaseous. At hydrations of 3 (±2) molecules of water per molecule of enzyme, activity is several orders-of-magnitude greater than nonenzymatic catalysis. Neutron spectroscopy indicates that the fast (≤nanosecond) global anharmonic dynamics of the anhydrous functional enzyme are suppressed. This indicates that neither hydration water nor fast anharmonic dynamics are required for catalysis by this enzyme, implying that one of the biological requirements of water may lie with its role as a diffusion medium rather than any of its more specific properties. 相似文献
116.
117.
David J. Finney 《Biometrical journal. Biometrische Zeitschrift》1993,35(2):253-256
Biometric interest often attaches to the product of two directly determined variables. In sugar production, for example, the yield of the desired commodity is the product of the total weight of cane or beet from unit area and the sugar content per unit weight. In crop and animal production, there are many analogous situations where experimental or other information may come from field plots or individual animals and the success of inferences or decisions is related to the frequency distribution of such a product. The voluminous published literature relating to frequency distributions appears to contain little that is directly relevant. It therefore seems worth placing on record results recently obtained for the third and fourth moments of a product in the simple case of both variables being Normally distributed. 相似文献
118.
119.
Regulation of the interleukin 4 signal in human B-lymphocytes 总被引:2,自引:0,他引:2
120.
Weekley CM Aitken JB Vogt S Finney LA Paterson DJ de Jonge MD Howard DL Musgrave IF Harris HH 《Biochemistry》2011,50(10):1641-1650
Selenium compounds exhibit chemopreventative properties at supranutritional doses, but the efficacy of selenium supplementation in cancer prevention is dependent on the chemical speciation of the selenium supplement and its metabolites. The uptake, speciation, and distribution of the common selenoamino acid supplements, selenomethionine (SeMet) and Se-methylselenocysteine (MeSeCys), in A549 human lung cancer cells were investigated using X-ray absorption and fluorescence spectroscopies. X-ray absorption spectroscopy of bulk cell pellets treated with the selenoamino acids for 24 h showed that while selenium was found exclusively in carbon-bound forms in SeMet-treated cells, a diselenide component was identified in MeSeCys-treated cells in addition to the carbon-bound selenium species. X-ray fluorescence microscopy of single cells showed that selenium accumulated with sulfur in the perinuclear region of SeMet-treated cells after 24 h, but microprobe selenium X-ray absorption near-edge spectroscopy in this region indicated that selenium was carbon-bound rather than sulfur-bound. X-ray absorption and X-ray fluorescence studies both showed that the selenium content of MeSeCys-treated cells was much lower than that of SeMet-treated cells. Selenium was distributed homogeneously throughout the MeSeCys-treated cells. 相似文献