不同菱角壳提取物抑制肺癌A549细胞生长的研究

目的研究不同菱壳水和乙醇提取物的抗癌活性。方法采用Folin比色法测定不同品种菱壳提取物中多酚的含量,通过MTT法测定二角菱壳、四角菱壳的水提取物、醇提取物对肺癌A549细胞生长抑制作用。结果四角菱壳多酚含量高于二角菱壳,醇提物多酚含量高于水提物;二角菱壳醇提取物对肺癌A549细胞的抑制率高于水提物,差异具有统计学意义(P<0.01);四角菱壳水提物对抑制率高于二角菱壳水提物肺癌A549细胞的生长,差异具有统计学意义(P<0.01)。结论菱角壳提取物对肺癌A549细胞生长具有较强的抑制作用,且菱角壳的醇提取物优于水提取物,四菱角壳优于二角菱壳。     

N2和O2冷等离子体处理对木材胶合强度的影响

采用N2、O2两种等离子体气体分别处理木材,处理功率为300 W,处理时间为5 min,将处理后的木材采用MUF胶粘合起来,测试了胶合强度,并对冷等离子体处理前后的木材表面能进行了分析。实验结果表明:经N2、O2冷等离子体处理后的木材表面的接触角明显减小,表面自由能明显增大;经冷等离子体处理后的胶合板的平均干状胶合强度和湿状强度均有明显(50%以上)增大。     

Coxofemoral joint radiography in standing cattle

The objective of this study was to establish a technique for radiographic examination of the coxofemoral joint and adjacent bony structures in standing cattle. Left (or right) 30° dorsal-right (or left) ventral radiographic views of the coxofemoral joint region of standing cattle (n = 10) with hind limb lameness were evaluated retrospectively. In addition, an experimental study of oblique laterolateral views of the coxofemoral joint region of a bovine skeleton at angles of 15-45° was carried out to determine the optimal position for visualization of the hip region. In the 10 clinical patients, the bodies of the ilium and ischium, the acetabulum and proximal third of the femur could be assessed. Six of these cattle had fractures of the body of the ilium and body of the ischium, five with and one without involvement of the acetabulum, two had craniodorsal and one caudoventral luxation of the femur and one had a femoral neck fracture. The described laterodorsal-lateroventral radiographs of the hip region in standing cattle were suitable for assessing the coxofemoral joint, the proximal aspect of the femur and parts of the ischium, ilium and pubis. After testing the optimal angle on the skeleton, it was seen that distortion and superimposition were minimized by positioning the X-ray beam at an angle of 25° to the horizontal plane. It can be concluded that the described technique improves the evaluation of injuries of the coxofemoral region in cattle. With the appropriate angle, the technique can also be applied in recumbent cattle.     

An experiment study of the realization of diesel engine emission standard of Euro IV

This paper calibrates the advanced injector angle and EGR of a four-in-line pressure engine on the specialized test stand, which makes the NOx achieved the standard of Euro IV. Then an experiment study of the diesel oxidation catalyst (DOC) and the particulate oxidation catalyst (POC) are made. Both make the diesel engine emission achieving the Standard of Euro IV. This experiment study shows a kind of method that realizing diesel engine emission standard of Euro IV, and concludes the character and law of the method.     

基于交角的林木竞争指数

建立基于交角的林木竞争指数(u_a_CIi),该指数能够同时表达出竞争木对对象木的上方遮盖和侧翼挤压。该指数取值范围为[0,1),无量纲,指数值越大,表明树体越小,所承受的竞争压力越大,清晰直观地表达林木在林分中所处的相对竞争态势。从理论上阐明大的竞争邻体比小的竞争邻体对对象木有更大影响,不仅反映在上方的遮盖也体现在侧方的挤压中。该指数与林木大小的相关性明显高于常用的HEGYI竞争指数。在测量技术飞速发展的今天,该竞争指数将具有很大的应用前景。     

水稻叶面积分布构成因子的数值模拟

叶面积分布是水稻株型研究的重要内容.通过机理分析建立了叶面积指数和叶面积分布模型,利用田间试验数据检验模型,通过数值模拟探讨节间距对叶面积分布影响的机理.模型检验效果良好,数值模拟结果可信,能为叶面积分布的优化提供理论基础.     

Variation in selected solid wood properties of young Pinus patula from diverse sites in the Mpumalanga escarpment area in South Africa

Regression analyses identified ‘Growth Days’ (an index expressing site moisture availability) as the only site variable contributing significantly to the prediction to wood density (R² = 0.57), whereas the model predicting grain angle included only ‘Altitude’ (R² = 0.60). These results surfaced during an investigative study to quantify various sources of variation in wood properties and to quantify the effect of a number of site factors on wood properties of Pinus patula grown in the Mpumalanga escarpment area of South Africa. For this purpose, 10 trees were sampled from each of 17 diverse sites for wood property analyses. The effects of site, distance from the pith and differences between trees within site on wood density, transverse shrinkage, grain angle and dynamic modulus of elasticity were investigated. The site factors considered included a wide variety of soil and climatic factors. The effect of radial distance from the pith and differences between individual trees within sites were highly significant, accounting for most of the variation in wood properties. Although the effects of a number of site factors were statistically significant, they generally explained relatively small but important variation in wood properties among sites. The study not only quantified the effects of important sources of variation on a few key wood properties, but it also revealed that the extent of differences between sites can be explained in terms of some specific site factors. It is envisaged that the results will contribute significantly towards the refinement of current forest site classification systems for improved decision-making with respect to wood quality in intensively managed plantation systems.     

Inclination Angle Affects Ozone Injury in the Flag Leaf of Rice

Abstract

To evaluate the effect of inclination angle of the leaf on the leaf injury of rice by O₃, we examined the effect of a 5-hr exposure to 0, 0.1, 0.3 cm³ m-³ O₃, abbreviated as O⁰, O^0.1 and O^0.3, respectively, of the flag leaf using natural-light gas-exposure chambers. The middle portion of the flag leaf was set horizontally using lead weights (H plant) and it was compared with a non-treated, erect leaf (E plant). Gas exchange and chlorophyll fluorescence were measured immediately before, immediately after, and 1 and 3 d after the start of the exposure. The net photosynthetic rate, stomatal conductance and operating quantum efficiency of photosystem II (F_q’/F_m’) were decreased by the exposure to O₃. Furthermore, the inhibitory effects of O^0.1 and O^0.3 on the H plants were severer than those on the E plants. The maximum quantum efficiency of photosystem II (F_v/F_m) in the leaf of H plants decreased immediately after exposure to O₃. These results indicate that the weaker inhibitory effect of O₃ on the erect leaf depends on the lower light intensity at the leaf surface, rather than the horizontal leaf position.

Key words: Ascorbic acid, Chlorophyll fluorescence, Gas exchange, Leaf inclination angle, Oryza sativa, O₃, Quantum efficiency.     

细胞壁微纤丝角和结晶区对木材物理力学性能影响研究进展

木材是由不同种类的细胞组成的天然材料,其实体物质是组成其结构的各类型细胞的细胞壁。细胞壁的超微构造主要包括微纤丝和结晶区,微纤丝角能表征纤维素微纤丝的取向,纤维素大分子链排列的有序程度及排列形态决定其结晶程度和微晶形态等结晶区特征。基于前人的研究,系统概述了细胞壁微纤丝和结晶区对木材物理力学性能影响的研究进展,重点围绕微纤丝角和结晶度2个方面,分别归纳了二者对木材密度、尺寸稳定性、木材声学等物理性质以及弹性模量、强度等力学性质的影响作用,同时阐述了微纤丝角与木材硬度和刚度以及结晶度与冲击韧性等的相互关系,并概述了细胞壁微晶形态对木材润湿性和纤维强度影响方面的研究进展,最后对今后的研究方向进行了展望。     

西藏原始林芝云杉林空间结构参数分布特征

以藏东南波密岗乡自然保护区原始林芝云杉林为研究对象,应用空间结构参数角尺度、混交度和大小比数,建立空间结构参数的三元分布,揭示林分的空间结构特征。结果表明,从一元分布看,林木整体属于随机分布,林分强度混交,树种的优劣程度参差不齐,整体处于中庸状态;在混交度和角尺度分布中,以随机分布和强度混交林木株数最多,大小比-角尺度组合中,均以随机分布轴线和中庸轴线两侧基本对称;三元结构参数组合为强度混交、随机分布、亚优势状态林木分布较多。主要树种的混交程度较高,呈现强度和极强度混交状态;其中林芝云杉和华山松为该群落的优势树种随机分布,其他主要树种都为轻度聚集分布;树种间大小比数差异明显,其中林芝云杉最低,<0.252,处于亚优势状态。全面分析原始林芝云杉林的空间结构,为林芝云杉林结构优化调整提供重要参考,为藏东南天然林可持续发展提供科学依据。