We used whole-tree agarwood-induction technology to produce agarwood from Aquilaria sinensis trees within 20 months, and evaluated the quality of this agarwood. The results showed its characteristics were similar to t...We used whole-tree agarwood-induction technology to produce agarwood from Aquilaria sinensis trees within 20 months, and evaluated the quality of this agarwood. The results showed its characteristics were similar to those of high-grade wild agarwood in terms of texture, chemical constituents, essential oil content, and ethanol-soluble extract content, with the lattermost quality far surpassing the requirement of traditional Chinese medicine agarwood, as indicated in Chinese Pharmacopoeia 2010. To the best of our knowledge, this is first study to show that high-quality agarwood can be produced in whole A. sinensis trees via a chemically induced technology.展开更多
In the northeastern United States, whole-tree harvesting is widely used to supply fuel to biomass energy facilities, but questions remain regarding its long-term sustainability. We have previously reported findings in...In the northeastern United States, whole-tree harvesting is widely used to supply fuel to biomass energy facilities, but questions remain regarding its long-term sustainability. We have previously reported findings indicating no short-term decrease in forest productivity in whole-tree harvested sites when compared with similar conventionally (stem-only) harvested sites. Here we present additional results of the same study, but focus on the effect harvest treatment has on the species composition of the regenerating forest. Within northern hardwood forests in central New Hampshire and western Maine, regeneration surveys were conducted on four (4) small clearcuts in 2010 and twenty-nine (29) small clearcuts in 2011. The species and diameter of trees > 2 m in height were recorded within 1 m or 2 m-radius plots and used to calculate the biomass fraction of each species. The 2010 study additionally measured the density of trees 2 m in height and the diversity of understory non-tree species. Non-metric multidimensional scaling and multi-response permutation procedures were used to determine the effect of harvest treatment had on community-wide tree species composition. Potential differences were also examined on a species-by-species basis. Both analytic methods indicated no significant differences in species composition of tree species or understory communities. Within the limits of our data, we conclude that no significant effects of residue removal on species composition are observed within our sample of northern hardwood sites at this early stage of stand development.展开更多
Objective: Agarwood—a resinous wood produced by Aquilaria plants in response to injury or artificial induction—is a valuable medicinal and fragrance resource. Whole-Tree Agarwood-Inducing Technique(Agar-WIT) has bee...Objective: Agarwood—a resinous wood produced by Aquilaria plants in response to injury or artificial induction—is a valuable medicinal and fragrance resource. Whole-Tree Agarwood-Inducing Technique(Agar-WIT) has been widely used to produce agarwood. However, the time-dependent characteristics of agarwood formation induced by Agar-WIT are yet to be clarified. To promote technologically efficient utilization and upgradation of Agar-WIT, the dynamic process and mechanism of agarwood formation were analyzed for one year.Methods: Agarwood formation percentage, barrier layer microscopic properties, extract levels, compound level, and characteristic chromatograms of agarwood were examined by referring to the Chinese Pharmacopeia(2020 version).Results: Agar-WIT could maintain a high percentage of agarwood formation over one year compared with that of healthy plants. Alcohol-soluble extract and agarotetrol levels showed fluctuating cyclic changes with peaks occurring first during the fifth and sixth months, and subsequently in the 11th month.Aquilaria trees subjected to Agar-WIT treatment for 1–12 months showed significant characteristics of a dynamic agarwood formation process. The barrier layer began to appear in the fourth month after treatment. Alcohol-soluble extractive levels in agarwood formed in the second month, and thereafter,exceeded 10.0%, and agarotetrol in agarwood produced after four months or later, exceeded 0.10%.Conclusion: According to the Chinese Pharmacopoeia, alcohol-soluble extractive levels in agarwood should not be less than 10.0% and agarotetrol level should exceed 0.10%. After four months of Agar-WIT treatment, the formed agarwood theoretically met these standards and was suitable for developed and utilization. However, the optimal harvest time was found to be the 11th month, followed by the sixth month after Agar-WIT treatment. Therefore, Agar-WIT resulted in swift agarwood formation and stable accumulation of alcohol-soluble extracts and agarotetrol. Thus, this method is efficient for large-scale cultivation of Aquilaria sinensis to produce agarwood and provide raw materials for the agarwood medicinal industry.展开更多
目的基于血常规数据开发结直肠癌预测模型,以提高结直肠癌筛查参与率,降低筛查成本,提高结直肠癌筛查准确性。方法收集4554例患者依据结肠镜和病理结果分为正常对照组(1899例)、息肉组(2259例)和结直肠癌组(396例)。按7∶3比例分别将各...目的基于血常规数据开发结直肠癌预测模型,以提高结直肠癌筛查参与率,降低筛查成本,提高结直肠癌筛查准确性。方法收集4554例患者依据结肠镜和病理结果分为正常对照组(1899例)、息肉组(2259例)和结直肠癌组(396例)。按7∶3比例分别将各组随机分为训练集和验证集,采用梯度提升树机器学习算法分别建立癌vs非癌、癌vs正常对照、癌vs息肉和息肉vs正常对照预测模型。模型基于曲线下面积(area under the curve,AUC)进行评估。结果构建梯度提升树模型,AUC作为模型准确性评价指标,上述4个模型在验证集的AUC值依次为0.891、0.921、0.871和0.772,三个结直肠癌预测模型AUC值均>0.80。结论本研究所开发的结直肠癌预测模型可鉴别验证数据集中的癌与非癌人群,模型的泛化能力还需外部独立数据集进一步验证。展开更多
利用G ran ier热消散探针在2003年10月测定了广东鹤山丘陵地马占相思林14株样树的树干液流,同时监测林冠上方的光合有效辐射、空气湿度和气温,结合树木的形态和林分的结构特征,计算马占相思的整树蒸腾(E)、林分总蒸腾(Et)以及冠层平均...利用G ran ier热消散探针在2003年10月测定了广东鹤山丘陵地马占相思林14株样树的树干液流,同时监测林冠上方的光合有效辐射、空气湿度和气温,结合树木的形态和林分的结构特征,计算马占相思的整树蒸腾(E)、林分总蒸腾(Et)以及冠层平均气孔导度(gc),分析树形特征与整树水分利用的关系、冠层气孔导度对光合有效辐射(PAR)和空气水汽压亏缺(D)的响应.结果表明,整树蒸腾与胸径(P<0.0001)、边材面积(P<0.0001)和冠幅(P=0.0007)以自然对数的形式、与树高(P=0.014)以幂函数的形式呈现显著正相关.冠层气孔导度最大值(gcm ax)随D的上升呈对数函数下降(P<0.0001),对光合有效辐射的响应则呈双曲线函数增加(P<0.0001).液流测定系统能提供连续和准确的整树和林分蒸腾速率值,经严格数学推导公式计算,最终可求出冠层气孔导度,是研究森林水分利用与环境因子相互关系的有效方法.展开更多
基金supported by the National Key Technology R&D Program(No.2011BAI01B07)National Natural Science Foundation of China(Nos.81173481 and 31000136)+1 种基金Beijing Municipal Natural Science Foundation(No. 6102024)the key project in the Science & Technology Program of Hainan Provincial(No.ZDXM20120033)
文摘We used whole-tree agarwood-induction technology to produce agarwood from Aquilaria sinensis trees within 20 months, and evaluated the quality of this agarwood. The results showed its characteristics were similar to those of high-grade wild agarwood in terms of texture, chemical constituents, essential oil content, and ethanol-soluble extract content, with the lattermost quality far surpassing the requirement of traditional Chinese medicine agarwood, as indicated in Chinese Pharmacopoeia 2010. To the best of our knowledge, this is first study to show that high-quality agarwood can be produced in whole A. sinensis trees via a chemically induced technology.
文摘In the northeastern United States, whole-tree harvesting is widely used to supply fuel to biomass energy facilities, but questions remain regarding its long-term sustainability. We have previously reported findings indicating no short-term decrease in forest productivity in whole-tree harvested sites when compared with similar conventionally (stem-only) harvested sites. Here we present additional results of the same study, but focus on the effect harvest treatment has on the species composition of the regenerating forest. Within northern hardwood forests in central New Hampshire and western Maine, regeneration surveys were conducted on four (4) small clearcuts in 2010 and twenty-nine (29) small clearcuts in 2011. The species and diameter of trees > 2 m in height were recorded within 1 m or 2 m-radius plots and used to calculate the biomass fraction of each species. The 2010 study additionally measured the density of trees 2 m in height and the diversity of understory non-tree species. Non-metric multidimensional scaling and multi-response permutation procedures were used to determine the effect of harvest treatment had on community-wide tree species composition. Potential differences were also examined on a species-by-species basis. Both analytic methods indicated no significant differences in species composition of tree species or understory communities. Within the limits of our data, we conclude that no significant effects of residue removal on species composition are observed within our sample of northern hardwood sites at this early stage of stand development.
基金supported by the funding from the National Key Research and Development Project of China (2018YFC1706400)。
文摘Objective: Agarwood—a resinous wood produced by Aquilaria plants in response to injury or artificial induction—is a valuable medicinal and fragrance resource. Whole-Tree Agarwood-Inducing Technique(Agar-WIT) has been widely used to produce agarwood. However, the time-dependent characteristics of agarwood formation induced by Agar-WIT are yet to be clarified. To promote technologically efficient utilization and upgradation of Agar-WIT, the dynamic process and mechanism of agarwood formation were analyzed for one year.Methods: Agarwood formation percentage, barrier layer microscopic properties, extract levels, compound level, and characteristic chromatograms of agarwood were examined by referring to the Chinese Pharmacopeia(2020 version).Results: Agar-WIT could maintain a high percentage of agarwood formation over one year compared with that of healthy plants. Alcohol-soluble extract and agarotetrol levels showed fluctuating cyclic changes with peaks occurring first during the fifth and sixth months, and subsequently in the 11th month.Aquilaria trees subjected to Agar-WIT treatment for 1–12 months showed significant characteristics of a dynamic agarwood formation process. The barrier layer began to appear in the fourth month after treatment. Alcohol-soluble extractive levels in agarwood formed in the second month, and thereafter,exceeded 10.0%, and agarotetrol in agarwood produced after four months or later, exceeded 0.10%.Conclusion: According to the Chinese Pharmacopoeia, alcohol-soluble extractive levels in agarwood should not be less than 10.0% and agarotetrol level should exceed 0.10%. After four months of Agar-WIT treatment, the formed agarwood theoretically met these standards and was suitable for developed and utilization. However, the optimal harvest time was found to be the 11th month, followed by the sixth month after Agar-WIT treatment. Therefore, Agar-WIT resulted in swift agarwood formation and stable accumulation of alcohol-soluble extracts and agarotetrol. Thus, this method is efficient for large-scale cultivation of Aquilaria sinensis to produce agarwood and provide raw materials for the agarwood medicinal industry.
文摘目的基于血常规数据开发结直肠癌预测模型,以提高结直肠癌筛查参与率,降低筛查成本,提高结直肠癌筛查准确性。方法收集4554例患者依据结肠镜和病理结果分为正常对照组(1899例)、息肉组(2259例)和结直肠癌组(396例)。按7∶3比例分别将各组随机分为训练集和验证集,采用梯度提升树机器学习算法分别建立癌vs非癌、癌vs正常对照、癌vs息肉和息肉vs正常对照预测模型。模型基于曲线下面积(area under the curve,AUC)进行评估。结果构建梯度提升树模型,AUC作为模型准确性评价指标,上述4个模型在验证集的AUC值依次为0.891、0.921、0.871和0.772,三个结直肠癌预测模型AUC值均>0.80。结论本研究所开发的结直肠癌预测模型可鉴别验证数据集中的癌与非癌人群,模型的泛化能力还需外部独立数据集进一步验证。
文摘利用G ran ier热消散探针在2003年10月测定了广东鹤山丘陵地马占相思林14株样树的树干液流,同时监测林冠上方的光合有效辐射、空气湿度和气温,结合树木的形态和林分的结构特征,计算马占相思的整树蒸腾(E)、林分总蒸腾(Et)以及冠层平均气孔导度(gc),分析树形特征与整树水分利用的关系、冠层气孔导度对光合有效辐射(PAR)和空气水汽压亏缺(D)的响应.结果表明,整树蒸腾与胸径(P<0.0001)、边材面积(P<0.0001)和冠幅(P=0.0007)以自然对数的形式、与树高(P=0.014)以幂函数的形式呈现显著正相关.冠层气孔导度最大值(gcm ax)随D的上升呈对数函数下降(P<0.0001),对光合有效辐射的响应则呈双曲线函数增加(P<0.0001).液流测定系统能提供连续和准确的整树和林分蒸腾速率值,经严格数学推导公式计算,最终可求出冠层气孔导度,是研究森林水分利用与环境因子相互关系的有效方法.
