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21.
Lead accumulation in roadside soil and grass   总被引:12,自引:0,他引:12  
T J Chow 《Nature》1970,225(5229):295-296
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Inversion of the G DNA segment of phage Mu controls phage infectivity   总被引:35,自引:0,他引:35  
D Kamp  R Kahmann  D Zipser  T R Broker  L T Chow 《Nature》1978,271(5645):577-580
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The colour appearance of dyed textile materials changes with the viewing condition, especially with a change in the light source or Illuminant. The attitude and magnitude of the change vary with the hue of the colour, the light absorbance nature of the dye and the colour depth to which it is dyed. This paper examines the change in colour appearance of reactive - dyed cotton when the light source is changed from CIE Uluminant D65 to CIE illuminant A. Reactive dyes of primary hues were selected and applied at various depths and the dyed colours were assessed with reference to changing the illuminant.  相似文献   
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We sequenced eight melanoma exomes to identify new somatic mutations in metastatic melanoma. Focusing on the mitogen-activated protein (MAP) kinase kinase kinase (MAP3K) family, we found that 24% of melanoma cell lines have mutations in the protein-coding regions of either MAP3K5 or MAP3K9. Structural modeling predicted that mutations in the kinase domain may affect the activity and regulation of these protein kinases. The position of the mutations and the loss of heterozygosity of MAP3K5 and MAP3K9 in 85% and 67% of melanoma samples, respectively, together suggest that the mutations are likely to be inactivating. In in vitro kinase assays, MAP3K5 I780F and MAP3K9 W333* variants had reduced kinase activity. Overexpression of MAP3K5 or MAP3K9 mutants in HEK293T cells reduced the phosphorylation of downstream MAP kinases. Attenuation of MAP3K9 function in melanoma cells using siRNA led to increased cell viability after temozolomide treatment, suggesting that decreased MAP3K pathway activity can lead to chemoresistance in melanoma.  相似文献   
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Circulating protein C (PC) plays a vital role as an anti-coagulant and anti-inflammatory mediator. We show here that human endothelial cells produce PC that acts through novel mediators to enhance their own functional integrity. When endogenous PC or its receptor, endothelial protein C receptor (EPCR), was suppressed by small interfering (si) RNA, human umbilical cord endothelial cell (HUVEC) proliferation was decreased and apoptosis elevated. Interestingly, PC or EPCR siRNA significantly increased HUVEC permeability, which is likely via reduction of the angiopoietin (Ang)1/Ang2 ratio and inhibition of the peripheral localization of the tight junction protein, zona occludins-1. In addition, PC or EPCR siRNA inhibited type IV collagen and matrix metalloproteinase-2, providing the first evidence that PC contributes to vascular basement membrane formation. These newly described actions of endogenous PC act to stabilize endothelial cells and enhance barrier function, to potentially promote the functional integrity of blood vessels.  相似文献   
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1Lens is placed in beam waist We consider the case of a Gaussian beam that is incident at its waist on a thin lens of focal length f.To find the location of the waist of the output beam and the beam radius at that point,we start with the ABCD law.  相似文献   
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