As an alternative to absolute error methods, such as the least square and least absolute deviation estimations, a product relative error estimation is proposed for a multiplicative single index regression model. Regre...As an alternative to absolute error methods, such as the least square and least absolute deviation estimations, a product relative error estimation is proposed for a multiplicative single index regression model. Regression coefficients in the model are estimated via a two-stage procedure and their statistical properties such as consistency and normality are studied. Numerical studies including simulation and a body fat example show that the proposed method performs well.展开更多
In this study, freeze-dried water extract from the leaves of Myristica fragrans （Houtt.） was tested for mutagenic and antimutagenic potentials using the Allium cepa assay. Freeze-dried water extract alone and its co...In this study, freeze-dried water extract from the leaves of Myristica fragrans （Houtt.） was tested for mutagenic and antimutagenic potentials using the Allium cepa assay. Freeze-dried water extract alone and its combination with cyclophosphamide （CP） （50 mg/kg） were separately dissolved in tap water at 500, 1000, 2000, and 4000 mg/kg. Onions （A. cepa） were suspended in the solutions and controls for 48 h in the dark. Root tips were prepared for microscopic evaluation. 2,2-Diphenyl-l-picrylhydrazyl （DPPH） free radicals＇ scavenging power of the extract was tested using butylated hydroxyanisole （BHA） and butylated hydroxytoluene （BHT） as standards. Water extract of Myristica fragrans scavenged free radicals better than BHA, but worse than BHT. The extract alone, as well as in combination with CP suppressed cell division, and induced chromosomal aberrations that were insignificantly different from the negative control （P≤0.05）. However, cytotoxic and mutagenic actions of CP were considerably suppressed. The observed effects on cell division and chromosomes of A. cepa may be principally connected to the antioxidant properties of the extract. The obtained results suggest mitodepressive and antimutagenic potentials of water extract of the leaves of M. fragrans as desirable properties of a promising anticancer agent.展开更多
基金supported by the National Natural Science Foundation of China under Grant Nos.11231010 and 11471302
文摘As an alternative to absolute error methods, such as the least square and least absolute deviation estimations, a product relative error estimation is proposed for a multiplicative single index regression model. Regression coefficients in the model are estimated via a two-stage procedure and their statistical properties such as consistency and normality are studied. Numerical studies including simulation and a body fat example show that the proposed method performs well.
文摘In this study, freeze-dried water extract from the leaves of Myristica fragrans （Houtt.） was tested for mutagenic and antimutagenic potentials using the Allium cepa assay. Freeze-dried water extract alone and its combination with cyclophosphamide （CP） （50 mg/kg） were separately dissolved in tap water at 500, 1000, 2000, and 4000 mg/kg. Onions （A. cepa） were suspended in the solutions and controls for 48 h in the dark. Root tips were prepared for microscopic evaluation. 2,2-Diphenyl-l-picrylhydrazyl （DPPH） free radicals＇ scavenging power of the extract was tested using butylated hydroxyanisole （BHA） and butylated hydroxytoluene （BHT） as standards. Water extract of Myristica fragrans scavenged free radicals better than BHA, but worse than BHT. The extract alone, as well as in combination with CP suppressed cell division, and induced chromosomal aberrations that were insignificantly different from the negative control （P≤0.05）. However, cytotoxic and mutagenic actions of CP were considerably suppressed. The observed effects on cell division and chromosomes of A. cepa may be principally connected to the antioxidant properties of the extract. The obtained results suggest mitodepressive and antimutagenic potentials of water extract of the leaves of M. fragrans as desirable properties of a promising anticancer agent.
