A Combined Product Estimator in Sample Survey

For the estimation of the population mean in stratified random sampling a ‘Combined Product Estimator’ is proposed which is more efficient than the ‘Combined Ratio’ and ‘Separate Ratio’ estimators. Also, the proposed estimator have exact expressions for bias and mean square error. An empirical illustration is given to compare the efficiencies of different estimators.     

Investigating the role of Aurora kinases in RAS signaling

Activating ras mutations are frequently found in malignant tumors of the pancreas, colon, lung and other tissues. RAS activates a number of downstream pathways that ultimately cause cellular transformation. Several recent studies suggested that one of those pathways involves Aurora kinases. Overexpression of Aurora‐B kinase can augment transformation by oncogenic RAS, however the mechanism was not determined. The cooperative effect of high levels of Aurora kinase is important since this kinase is frequently overexpressed in human tumors. We have used two Aurora kinase inhibitors to test their effect on RAS signaling. We find that these inhibitors have no effect on the phosphorylation of MEK1/2 or MAPK in response to RAS. Furthermore, inhibiting Aurora kinases in human cancer cells with or without activated RAS did not change the length of the cell cycle nor induce apoptosis suggesting that these kinases do not play a direct role in these key cellular responses to activated RAS. Overexpression of Aurora B can cause cells to become polyploid. Also, inducing polyploidy with cytochalasin D was reported to induce neoplastic transformation, suggesting that Aurora overexpression may cooperate with RAS indirectly by inducing polyploidy. We find that inducing polyploidy with cytochalasin D or blebbistatin does not enhance transformation by oncogenic RAS. Our observations argue against a direct role for Aurora kinases in the RAS‐MAPK pathway, and suggest that the polyploid state does not enhance transformation by RAS. J. Cell. Biochem. 106: 33–41, 2009. © 2008 Wiley‐Liss, Inc.     

An Efficient Regression Type Estimator in Survey Sampling

For the estimation of population mean in simple random sampling, an efficient regression-type estimator is proposed which is more efficient than the conventional regression estimator and hence than mean per unit estimator, ratio and product estimators and many other estimators proposed by various authors. Some numerical examples are included for illustration.     

Effect of certain chelating agents on the antibacterial action of silver nitrate

EDTA and EGTA when used in conjunction with AgNO3 enhanced the antibacterial action of the latter significantly, so that strains of Klebsiella pneumoniae and Staphylococcus aureus resistant to 70 micrograms/ml of AgNO3 were observed to became sensitive to 10 micrograms/ml of this compound. The synergistic effect of EDTA appears to be due to a mechanism other than the removal of lipopolysaccharide from outer membrane, as its effect could be observed in even non-LPS containing gram positive S. aureus cells. Penicillamine, another potent chelator had an opposite effect so that it decreased the toxicity of silver ions.     

A Single-Gene Mutation Changed the Architecture of Pumpkin Seed: A Review

Journal of Plant Growth Regulation - Pumpkin seeds are used globally for snacks, bakery, and oil due to their nutritional and medicinal properties. The seeds of pumpkin have 35–45% oil, rich...