一种基于树树结构的低时延应用层组播模型

作为IP组播的替代,应用层组播具有简单灵活的优势,获得了广泛应用,但时延较大的缺点对性能影响较大.针对大规模应用层组播时延较大的问题,提出一种层次化的树树组播模型来降低应用层组播时延,该模型利用两层结构来组织和管理应用层组播组成员,并考虑节点性能和节点间时延来构建较低时延的组播树.当节点加入或退出组播组时,设计合适的组播树维护算法使得组播树的时延变化较小,满足低时延要求.计算机仿真表明该树树组播模型能够有效降低应用层组播的时延,改善大规模应用层组播性能,适合应用在大规模实时多媒体环境中.

黄牛奶树树茎醇提取物内服对狼疮肾炎并发尿路感染患者JAKSTAT信号通路的影响

目的 分析黄牛奶树树茎醇提取物对Janus激酶信号转导子与转录激活子途径(JAKSTAT)信号通路狼疮肾炎并发尿路感染的影响.方法 选取2022年6月—2023年6月于四川大学华西医院接受诊治的狼疮肾炎并尿路感染患者45例纳为研究对象,分成模型组、低剂量组、高剂量组各15例,另选同期于医院体检的健康者30名作为对照组;对照组和模型组不做处理,低剂量组、高剂量组分别给予15 g、30 g黄牛奶树树茎醇提取物调控;观察患者系统性红斑狼疮活动指数(SLEDAI)评分、24 h尿蛋白、不同因素尿路感染情况、尿路感染患者尿培养结果、血肌酐(Scr)、补体3(C3)、C4、血沉(ESR)、降钙素原(PCT)、超敏C-反应蛋白(hs-CRP)、白细胞(WBC)、白细胞介素-12(IL-12)、转化生长因子β1(TGF-β1)、IL-6水平.结果 45例尿路感染患者检出病原菌以大肠埃希菌为主;与对照组相比,模型组、低剂量组、高剂量组Scr、ESR、PCT、hs-CRP、WBC、IL-12、TGF-β1、IL-6均升高,C3、C4 下降(P<0.05);与模型组相比,低剂量组、高剂量组 Scr、ESR、PCT、hs-CRP、WBC、IL-12、TGF-β1、IL-6呈下降,而C3、C4呈升高(P<0.05);与低剂量组相比,高剂量组Scr、ESR、PCT、hs-CRP、WBC、IL-12、TGF-β1、IL-6水平均降低,C3、C4升高(P<0.05).结论 黄牛奶树树茎醇提取物是通过调节JAKSTAT信号通路,抑制炎症因子,平衡免疫功能,提高预防尿路感染的作用.

村村有人守 山山有人管 树树有人护——舒兰市大北林场安全生产工作侧记

舒兰市大北林场,成立于1958年,占地面积38524公顷、林地面积22238公顷,境内有133个村屯,总人口12万,是舒兰市面积最大、林区人口最多的林场。就是这样一个林场,几十年来不但没有发生过火灾,还从来没有发生过重伤以上生产安全事故。他们的秘诀是什么呢?当领导心中没数不行大北林场地处矿区,三县交界,人口稠密,省道乡路四通八达,环境十分复杂。为进一步加强管理。

丙烯腈/木粉接枝共聚物的合成及其水解物的吸附特性研究

以Fe2 +/H2 O2 作为引发剂 ,将丙烯腈和木粉进行接枝共聚 ,得到丙烯腈 /木粉接枝共聚物 (PANW ) ,再经适度水解的方法合成阳离子交换树脂———羧基木粉。研究影响接枝共聚反应的各种因素和水解条件 ,并讨论羧基木粉对重金属离子和阳离子型染料的吸附特性。实验结果表明 :( 1)在适量引发剂 (FeSO4 ·7H2 O =1g)和适当温度 ( 60℃ )作用下 ,可得到较高接枝增量和接枝率的PANW ;( 2 )在PANW的水解反应中 ,在碱性催化剂作用下 ,可得到羧基含量高的产物 ,但收率较低 ;而在酸性催化剂作用下 ,则得到羧基含量低的产物 ,但收率较高 ;( 3)羧基木粉对阳离子型染料———碱性桃红的吸附容量与起始浓度有关 ,本实验中 ,羧基木粉对碱性桃红的吸附容量最高可达 50 0mg/g ,对Cu2 +的吸附容量最高可达 39mg/g ;( 4 )经 0 .3mol/LHCl再生4次后 ,羧基木粉对碱性桃红的吸附容量保持在 4 4 0mg/g以上 ,在含有多种金属离子的溶液中 。

树鼩脂蛋白脂肪酶的cDNA克隆、组织分布及活性测定

目的了解不易感动脉粥样硬化动物树鼠句的脂蛋白脂肪酶的结构和活性特点,并与其它种属比较,探讨脂蛋白脂肪酶在树鼠句独特脂代谢中的作用。方法以树鼠句脂肪细胞mRNA反转录获得的cDNA一链为模板,应用SMART-RACE技术获得树鼠句脂蛋白脂肪酶的cDNA序列并推导出其氨基酸序列;实时定量PCR方法检测树鼠句脂蛋白脂肪酶mRNA在各组织中的分布;真核表达树鼠句和人脂蛋白脂肪酶蛋白,放射性同位素法测定二者的活性并比较。结果树鼠句脂蛋白脂肪酶cDNA序列全长为3293bp,其中编码区1437bp,编码20个氨基酸的信号肽和458个氨基酸的成熟蛋白,该成熟蛋白N-端比人脂蛋白脂肪酶多10个氨基酸。树鼠句脂蛋白脂肪酶与其它哺乳类动物的氨基酸序列同源性大于90%,功能域高度保守。树鼠句脂蛋白脂肪酶的组织表达谱比较广泛,在心肌和脂肪组织中大量表达,但在骨骼肌中未检测到,却在肝脏中有中低水平表达,与人脂蛋白脂肪酶在这两种组织中的表达相反。活性测定结果显示,树鼠句脂蛋白脂肪酶活性显著高于人(7.67倍),这与测定的树鼠句血浆低甘油三酯水平相符。结论树鼠句的高活性脂蛋白脂肪酶可能是其血浆低水平甘油三酯的主要原因。

Camptothecin and 10-Hydroxycamptothecin Accumulate Differentially Under Specific Developmental Control in Camptotheca acuminata

Camptotheca acuminata Decaisne is a tree unique to China, producing terpenoid indole alkaloid (TIA), camptothecin (CPT), and 10-hydroxycamptothecin (HCPT), which possesses strong anti-cancer bioactivity. The dynamics of HCPT and CPT during seed maturation, seed germination, postgerminative development and daily growth were measured by High Performance Liquid Chromatography (HPLC). This article provides some evidence for presenting the theory that each characteristic of HCPT and CPT accumulation is under developmental regulation and then attempt to elucidate the metabolic relationships between them. HCPT accumulates particularly in young tissues and organs and is relatively unstable, while the distribution of CPT is more ubiquitous and stable. Their different distribution properties suggest that HCPT and CPT are differentially regulated and play distinct roles:during development.

Different Responses of Camptothecin and 10-Hydroxycamptothecin to Heat Shock in Camptotheca acuminata Seedlings

Plants interact with their environment by producing a diverse array of secondary metabolites, one of which is alkaloid. In this study, alkaloids, including camptothecin (CPT) and 10-hydroxycamptothecin (HCPT), malondialdehyde (MDA) and chlorophyll contents were measured during heat shock in seedlings of Camptotheca acuminata Decaisne unique to China. Responses of different tissues, including young leaves, old leaves, buds and barks, to heat shock were examined in alkaloid changes. CPT and HCPT concentrations reached their peak values separately at 38 degreesC and 40 degreesC, which were below the lethal heat-shock temperature indicated by MDA and chlorophyll, and their great changes took place in young leaves. These results indicated that CPT and HCPT were involved in the C acuminata resistance against heat shock from its environment. Furthermore, plant rigidly observed the cost-benefit principle and mobilized and allocated limited alkaloid sources to young and reproductive tissues preferentially. In addition, HCPT displayed well-regulated changes during incubation at sublethal temperature, and this indicated that HCPT might play a more positively defensive role in enhancement of plant thermotolerance than CPT does.

Dynamics of profiles and storage of carbon dioxide in broadleaved/Korean forest in Changbai Mountain

CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR Inc. and LI-COR, 820) from Aug. to Oct. of 1999, Apr. to Jul. of 2000, and from Aug. 2002 to Sept. 2003. Based on the collected dada, the diurnal and seasonal dynamics of profiles and storage of carbon dioxide in the forest were analyzed. The diurnal CO2 profiles showed that the vertical distribution of CO2 concentration were different for daytime and nighttime, and the CO2 concentration was highest close to forest floor, no matter at daytime and nighttime. The seasonal profiles of CO2 showed that stratification in the canopy was evident during growth season. CO2 concentrations at different heights (60 m to 2.5 m) had a little change in March, with a difference of 10 mmolmol-1, but had a significant change in July, with a difference of 60 mmolmol-1. In July, there also existed a greater gradient of CO2 concentrations at canopy (22, 26 and 32 m), with a difference of 8 mmolmol-1. The calculated total storage (ΔC/Δt ) of CO2 in the air column with height of 40 m beneath eddy covariance instrument was negative, and made a little contribution to NEE.

Adaptive responses of Acer ginnala, Pyrus ussuriensis and Prunus davidiana seedlings to soil moisture stress

One-year-old seedlings of Amur maple (Acer ginnala Maxim), Ussurian pear (Pyrus ussuriensis Maxim) and David peach (Prunus davidiana Carr) were planted in pots in greenhouse and treated with four different soil moisture contents (75.0%, 61.1%, 46.4% and 35.4%). The results showed that net photosynthesis rate (NPR), transpiration rate (TR) and stomatal conductance (Sc) of seedlings of the three species decreased with the decease of soil moisture content, and Amur maple seedlings had the greatest change in those physiological indices, followed by Ussurian pear, David peach. Amur maple and Ussurian pear seedlings also presented a decrease tendency in water use efficiency (WUE) under lower soil moisture content, whereas this was reversed for David peach. Under water stress the biomass allocation to seedling root had a significant increase for all the experimental species. As to root/shoot ratio, Amur maple seedlings had the biggest increase, while David peach had the smallest increase. The leaf plasticity of Amur maple seedlings was greater, the leaf size and total leaf area decreased significantly as the stress was intensified. No significant change of leaf size and total leaf area was found in seedlings of Ussurian pear and David peach. It was concluded that Amur maple was more tolerant to soil moisture stress in comparison with David peach and Ussurian pear.

Effects of Ca^(2+)concentrations on accumulations of mineral elements in the components of Pteroceltis tatarinowii

The bark of Pteroce/tis tatarinowii is a raw material for manufacturing XuanPaper. The effects of Ca^(2+) concentrations on the accumulation of mineral elements in the bark,leaf and root of Pteroceltis tatarinowii were studied under controlled conditions. The types ofHoagland nutrient solution with three Ca^(2+) concentrations levels (200, 400 and 600 μg·g^(-1))and a control (without Ca^(2+)) were designed to culture Pteroceltis tatarinowii. After 6 months,contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and barkwere analyzed. The results indicated that Ca accumulations content in the root, leaf and bark hadpositively relation with Ca^(2+) concentrations (200, 400, 600 μg · g^(-1)), and the order of theCa content in the three components was root>leaf>bark. Ca content in the root treated with 600 μg·g^(-1) Ca^(2+) concentrations was 5.5 times as high as that of the control, and about 1.4 times ashigh as that of the root treated in 200 and 400 μg/g Ca^(2+) concentrations respectively. On thecontrary, K and Mg contents in the root, leaf and bark were negatively related to Ca^(2+)concentrations, especially in the bark, and their accumulation trend followed the order ofleaf>root>bark. K content in the bark treated with 600 μg ·g^(-1) Ca^(2+) concentrations was 39.3%of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200 μg ·g^(-1)and 400 μg ·g^(-1) Ca^(2+) concentrations respectively; Mg content in the bark treated with 600μg ·g^(-1) Ca^(2+) concentrations was 23.4% of that of the control, and was 27.1% and 35.4% ofthat of the bark treated with 200 and 400 μg·g^(-1) Ca^(2+) concentrations respectively. Comparedwith the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca^(2+)concentrations and their contents were in the order: root>leaf>bark. Based on the results of thisstudy, the experiment has been useful for providing academic bases in improving the bark quality ofPteroceltis tatarinowii on non-limestone soil.

Radial Variation in Sap Flux Density as a Function of Sapwood Thickness in Two Eucalyptus ( Eucalyptus urophylla ) Plantations

Radial variation in sap flux density (SFD) as a function of sapwood thickness is of importance in accurately estimating sap flux through sapwood area which, in turn, decides the precision of heat pulse application. However, until now, only a few studies have evaluated the magnitude and significance of sampling errors associated with radial gradients in SFD, which were based on the small monitoring measurement data from a few trees. Based on one year of heat pulse observation of two 3 - 4 years old Eucalyptus urophylla S. T.,P Blake plantations in Leizhou Peninsula, Guangdong Province, China, a way of data processing was developed to treat with the lots of SFD data measured from 39 trees. It was found that the radial variation in SFD as a function of sapwood thickness in the two eucalyptus plantation sites could be expressed as y = 3. 667 5x(3) - 7.295 5x(2) + 3.682 6x + 0. 567 4 (R-2 = 0. 939 1, n = 80, P = 0.01), where y is the ratio of SFD of a sensor to the average of four data in different depths, x is the ratio of a sensor depth to tire radial sapwood thickness. It was the same (as in the following equation) in Jijia site, y = 5.006 2x(3) - 9.116 1x(2) + 4. 454 4x + 0.463 4 (R-2 = 0. 806 9, n = 72, P = 0.01) in Hetou site. From cambium to heartwood, SFD showed some increases at first and then decreases continuously. However, because die trees were very young, the maximum SFD was only 0. 33 - 0. 36 times more than the minimum.

Determination of contents of 10-Hydroxycamptothecin in Camptotheca acuminata by high-performance liquid chromatogram

The determination method of 10-hydroxycamptothecin in Camptotheca acuminata fruits by high-performance liquid chromatogram (HPLC) was studied. The HPLC analysis was performed on a HIQ sil C18(4.6×250 mm) column with mobile phase of acetonitrilewater (3:7, V:V), flow rate 1 mLmin-1 and UV detective wavelength 266 nm. Extracting 10-hydroxycamptothecin by ultrasonic method from fruits of C. acuminata to prepare samples for analysis was systematically discussed. The optimal extraction condition was carried out by 60% alcohol solution at 60℃ for 50 minutes.

Effect of Continuous Cropping on Leaf Nutrient and Growth of Different Species of Poplar Plantation

[Objective]The paper was to study the effect of continuous cropping on leaf nutrient and growth of different species of poplar plantation.[Method] The tree height,diameter at breast height（DBH）,volume of different generations and species of poplar plantation in poplar production area in northern Jiangsu Province,as well as TN,TP and TK content in their leaves were determined through field investigation and indoor experiment.[Result] With the increasing generation,the changes of TN,TP and TK content in the leaves of different ages of two varieties of forest stand were also different.However,with the increasing tree ages,TN,TP and TK contents in leaves showed decrease trend.With the increasing generation,the changes of tree height of I-69 and I-72 poplar showed the similar trend.The effect of increasing generation on tree height of 7-year-old and 10-year-old poplar was relatively stable,showing decrease trend from generation to generation.The tree height of 4-year-old poplar first increased and then decreased with the increasing generation.The changes of DBH along with different generations were basically consistent with the changes of tree height.With the increasing cultivation generations,the volume of 7-year-old and 10-year-old poplar decreased with significant difference.[Conclusion ] The result provided basis for rational fertilization and management of poplar plantation,improvement of productivity of poplar plantation,and achievement of sustainable management of plantation.

Stem Respiration of a Larch (Larix gmelini) Plantation in Northeast China

Stem respiration is an important part of the activity of a tree and is an important source of CO2 evolution from a forest ecosystem. Presently, no standard methods are available for the accurate estimation of total stem CO2 efflux from a forest. In the current study, a 33-year-old (by the year 2001) larch (Larix gmelini Rupr.) plantation was measured throughout 2001-2002 to analyze its monthly and seasonal patterns of stem respiration. Stem respiration rate was also measured at different heights, at different daily intervals and any variation in the larch plantation was recorded. The relationship between stem temperature, growth status and respiration rate was analyzed. Higher respiration rates were recorded in upper reaches of the larch tree throughout the season and these were affected partially by temperature difference. Midday depression was found in the diurnal changes in stem respiration. In the morning, but not in the afternoon, stem respiration was positively correlated with stem temperature. The reason for this variation may be attributed to water deficit, which was stronger in the afternoon. In the larch plantation, a maximum 7-fold variation in stem respiration was found. The growth status (such as mean growth rate of stem and canopy projection area) instead of stem temperature difference was positively correlated with this large variation. An S-model (sigmoid curve) or Power model shows the greatest regression of the field data. In the courses of seasonal and annual changes of stem respiration, peak values were observed in July of both years, but substantial interannual differences in magnitude were observed. An exponential model can clearly show this regression of the temperature-respiration relationship. In our results, Q(10) values ranged from 2.22 in 2001 to 3.53 in 2002. Therefore, estimation of total stem CO2 efflux only by a constant Q(10) value may give biased results. More parameters of growth status and water status should be considered for more accurate estimation.

Study on the Explant Disinfection of Root Culture of Hevea brasiliensis

[Objective] The aim was to look for an effective way of decreasing explants contamination in the root tissue culture of Hevea brasiliensis.[Method] In order to study root tissue culture of H.brasiliensis,new roots from forest section after treatment for one month were as explants,and 1 g/L carbendazim,75% ethanol,0.1% mercuric chloride and Yipeilong with different concentrations were used as disinfectants for roots disinfection.[Result] Before conventional disinfection,root explants were treated by 1 g/L carbendazim for 2.5 h,and disinfected by 75% ethanol for 30 s and 0.1% HgCl2 for 6 min,then cultured on the callus induction medium supplemented with 0.1% Yipeilong.The results showed that the contamination rate of explants decreased to 44.59%,and 25.60% explants survived after cultured for 30 d.[Conclusion] The study could provide theoretical foundation for the decrease of explant contamination in the root tissue culture of H.brasiliensis.

Evaluation of modification effect of epoxy resin based on performance of asphalt mixtures

Based on the analysis of the main failures discovered in pavement on steel deck plate and the demanding service condition of the pavement on steel deck, high-temperature rutting test, low-temperature bending test and controlled stress flexural fatigue test are used to study the performance of asphalt mixtures modified by epoxy resin including high-temperature stability, low-temperature cracking-resistance, and fatigue cracking-resistance, which are served to evaluate the modification effect of epoxy resin of different contents. With the addition of epoxy resin, all the three performances are improved greatly. However, when the amount of epoxy resin added is over a certain value, the modification effect will be stable with no extra benefit detected. Finally, in terms of the properties of the three respects, 20%, 30%, 30% are given separately as the proposal adding contents.

TWO IMPROVED GRAPH-THEORETICAL CLUSTERING ALGORITHMS

Graph-theoretical approaches have been widely used for data clustering and image segmentation recently. The goal of data clustering is to discover the underlying distribution and structural information of the given data, while image segmentation is to partition an image into several non-overlapping regions. Therefore, two popular graph-theoretical clustering methods are analyzed, including the directed tree based data clustering and the minimum spanning tree based image segmentation. There are two contributions： （1） To improve the directed tree based data clustering for image segmentation, （2） To improve the minimum spanning tree based image segmentation for data clustering. The extensive experiments using artificial and real-world data indicate that the improved directed tree based image segmentation can partition images well by preserving enough details, and the improved minimum spanning tree based data clustering can well cluster data in manifold structure.

Mining condensed frequent subtree base

In frequent tree pattern mining, the number of frequent subtrees generated is often too large. To tackle this problem, the concept of condensed frequent subtree base is proposed. The base consists of the maximal frequent subtrees for a series of support thresholds. It is a subset of frequent subtrees, and is used to approximate the support of arbitrary frequent subtrees with guaranteed maximal error bound. In addition, an algorithm is developed to mine such a condensed subtree base in a database of labeled rooted ordered trees. The algorithm adopts the way of fight-most extension to generate systematically all frequent rooted ordered subtrees. Several techniques are proposed to prune the branches that do not correspond to the maximal frequent subtrees. Heuristic techniques are used to arrange the order of computation so that relatively expensive computation is avoided as much as possible. Experimental results show that the size of the base is less than 10% of that of the complete set, and the algorithm outperforms the previous algorithms.

About the Conjecture of Felicitous Trees

A tree T is felicitous if there is a labelling l of its vertices with distinct integers from the set {0,1,2,…,｜E(T)｜}, so that the induced edge labelling l′ defined by l′(e)=l(u)+l(v) mod ｜E(T)｜ for each e=uv∈E(T), assigns each edge e a different label. In this paper, we constructively proved that more classes of trees are felicitous. In the end, we gave a conjecture that every lobster tree is felicitous.

Laboratory evaluation of epoxy resin modified asphalt mixtures

The pavement performance of epoxy resin modified asphalt mixtures was investigated by the Marshall test, the indirect tensile test, the rutting test, the three-pointed bending test and the composite beam fatigue test. In comparison with the performance of epoxy resin modified asphalt mixtures, the performance of stone matrix asphalt mixtures （SMA10） was also investigated. The rutting test and composite beam fatigue test results show that the epoxy resin modified asphalt mixtures can improve permanent deformation and fatigue characteristics. They also show lower temperature susceptibility and greater resistance to moisture damage compared to the SMA10. Findings from the research indicate that the epoxy resin modified asphalt mixture provides an optional material for the pavement of long-span steel bridges in China due to profound performance and economic advantages.