Supervised Learning Method: Critical Analysis and Updating of Cubing Rate Formulas for Determining Bark Masses of Prunus africana (Hook. f.) Kalkman (Rosaceae) in Cameroon

The stem barks of Prunus africana are used in the treatment of the benign prostate. Cameroon is one of the important exporters of the barks. Despite the important measures adopted in Cameroon for sustaining its harvesting, some many chalenges still remain. The objective of this work is to refine the forest management parameters in relation to P. africana in the regions of Adamaoua and the South-West by developing a volume rate which makes it possible to estimate the production for a new stem. The work took place in two phases: in the South-West in 2010 and in Adamaoua in 2011. Data collection used the semi-direct method, while the cubing equation was deduced by the multiple linear regression method. Two models for volume estimation and three models for mass prediction were developed. The predictive parameters retained are diameter, height of the bole and thickness of the bark. Results show that the average mass of the dry bark for a given P. africana tree species is 27.55 ± 14.44 kg and this varies according to the site. The strong adjusted coefficient of determination (adjusted R2) observed illustrates the reliability of the proposed models. These models provide a reliable tool that can be adopted as a standard in Cameroon for P. africana.

臀果木提取物对前列腺组织细胞凋亡的诱导作用

臀果木提取物可诱导大鼠前列腺组织细胞凋亡。用该提取物处理大鼠，４ｄ，９ｄ和１４ｄ后取前列腺，用ＨＥ染色观察细胞形态变化，ＤＮＡ凝胶电泳和流式细胞术（ＦＣＭ）定性、定量ＤＮＡ的降解及凋亡率。结果前列腺组织出现表皮细胞萎缩；ＤＮＡ琼脂糖凝胶电泳出现“梯形”条带；细胞凋亡率背前叶、背侧叶和腹叶分别为０．６７％，３．４２％和６．４９％（４ｄ），０．３２％，７．２５％和１０．１２％（９ｄ），０．７７％，５．４３％和７．４６％（１４ｄ）。表明臀果木提取物能诱导大鼠前列腺背侧叶和腹叶细胞凋亡。