哈尔滨市街道绿化的生态效应

研究街道绿地组成与结构对城市环境和小气候的影响,对城市街道绿地的绿化设计具有重要的理论与实践意义.分别在2006年春、夏、秋不同季节,调查了哈尔滨市南直路、长江路、上坞路3条新建宽域街道与绿化相关的生态指标,并运用灰色关联度分析法,分析了新建街道的绿化生态效应.结果表明:在日变化规律和季节变化规律中,街道绿化树种的生态效应在不同街道、不同季节、一天中不同时段分别达到各自的极值;长江路夏季12:00-14:00达到降温极值、春季16:00-18:00出现遮光度极值、7:00-8:00出现负离子增加极值、11:00-13:00达到增湿极值,秋季16:00-18:00出现CO2吸收量极值、11:00-13:00达到噪音衰减量极值,南直路秋季11:00-13:00出现滞尘量极值;在不同季节生态效应的关联规律中,3条街道都在夏季表现出最佳总体绿化生态效应.灰色关联度分析表明,不同街道的总体绿化生态效应不同,以上坞路的总体绿化生态效应最为显著.街道绿化形式与模式不同,其生态效应也显著不同,街道绿地组成与结构对街道生态效应的发挥有较大影响.     

Magnitude of modulation of gene expression in aneuploid maize depends on the extent of genomic imbalance

Aneuploidy has profound effects on an organism,typically more so than polyploidy,and the basis of this contrast is not fully understood.A dosage series of the maize long arm of chromosome 1(1L)was used to compa re relative global gene expression in diffe rent types and degrees of aneuploidy to gain insights into how the magnitude of genomic imbalance as well as hypoploidy affects global gene expression.While previously available methods require a selective examination of specific genes,RNA sequencing provides a whole-genome view of gene expression in aneuploids.Most studies of global aneuploidy effects have concentrated on individual types of aneuploids because multiple dose aneuploidies of the same genomic region are difficult to produce in most model genetic organisms.The genetic toolkit of maize allows the examination of multiple ploidies and 1-4 doses of chromosome arms.Thus,a detailed examination of expression changes both on the varied chromosome arms and elsewhere in the genome is possible,in both hypoploids and hyperploids,compared with euploid controls.Previous studies observed the inverse trans effect,in which genes not varied in DNA dosage were expressed in a negative relationship to the varied chromosomal region.This response was also the major type of changes found globally in this study.Many genes varied in dosage showed proportional expression changes,though some were seen to be partly or fully dosage compensated.It was also found that the effects of aneuploidy were progressive,with more severe aneuploids producing effects of greater magnitude.     

In situ Reduction of Silver Nanoparticles on Chitosan Hybrid Copper Phosphate Nanoflowers for Highly Efficient Plasmonic Solar-driven Interfacial Water Evaporation

The development of water purification device using solar energy has received tremendous attention.Despite extensive progress,traditional photothermal conversion usually has a high cost and high environmental impact.To overcome this problem,we develop a low cost,durable and environmentally friendly solar evaporator.This bilayered evaporator is constructed with a thermal insulating polyvinylidene fluoride(PVDF)membrane as a bottom supporting layer and plasmonic silver nanoparticles decorated miero-sized hybrid flower(Ag/MF)as a top light-to-heat conversion layer.Compared with the sample with a flat silver film,the two-tier Ag/MF has a plasmonic enrichment property and high efficiency in converting the solar light to hcat as cach flower can gencrate a microscale hotspot by enriching the absorbed solar light.On the other hand,the PVDF membrane on the bottom with porous structure not only improves the mechanicalstability of the entire structure,but also maintains a stable water supply from the bulk water to the evaporation interface by capillarity and minimizes the thermal conduction.The combination of excellent water evaporation ability simple operation,and low cost of the production process imparts this type of plasmonic enhanced solar-driven interfacial water evaporator with promising prospects for potable water purification for point-of-use applications.     

Aerodynamic Characteristics, Power Requirements and Camber Effects of the Pitching-Down Flapping Hovering

The pitching-down flapping is a new type of bionic flapping,which was invented by the author based on previous studieson the aerodynamic mechanisms of fruit fly(pitching-up)flapping.The motivation of this invention is to improve the aerodynamiccharacteristics of flapping Micro Air Vehicles(MAVs).In this paper the pitching-down flapping is briefly introduced.Themajor works include:(1)Computing the power requirements of pitching-down flapping in three modes(advanced,symmetrical,delayed),which were compared with those of pitching-up flapping;(2)Investigating the effects of translational accelerationtime,Δτ_t,and rotational time,Δτ_r,at the end of a stroke,and the angle of attack,α,in the middle of a stroke on the aerodynamiccharacteristics in symmetrical mode;(3)Investigating the effect of camber on pitching-down flapping.From the above works,conclusions can be drawn that:(1)Compared with the pitching-up flapping,the pitching-down flapping can greatly reduce thetime-averaged power requirements;(2)The increase in Δτt and the decrease in Δτ_r can increase both the lift and drag coefficients,but the time-averaged ratio of lift to drag changes a little.And α has significant effect on the aerodynamic characteristicsof the pitching-down flapping;(3)The positive camber can effectively increase the lift coefficient and the ratio of lift to drag.     

籼米淀粉粘滞性的基因型与环境互作研究

水稻精米中大约含有90%的淀粉,因此淀粉的特性对水稻的食味品质有很大的影响.淀粉粘滞性是预测稻米食用、蒸煮和加工品质的重要指标.本研究利用4个细胞质雄性不育系和8个恢复系配置的不完全双列杂交组合来分析淀粉粘滞性指标(崩解值、回复值和消减值)的胚乳、细胞质和母体基因效应及环境互作效应.结果表明在崩解值、回复值和消减值的遗传变异中,遗传主效应方差分量占了64%以上,表明它们主要受遗传主效应控制,同时也受到基因型与环境互作效应的影响.崩解值、回复值和消减值的总遗传率分别为67.8%、79.5%、79.5%,而且普通遗传率占了总遗传率的75%以上,表明对这些性状的早世代选择有效,且在不同环境中选择效果相对稳定.     

细胞外信号调节激酶在小鼠神经干细胞增殖中的作用

本文旨在探讨细胞外信号调节激酶(extracellular signal-regulated kinase 1/2, ERK1/2)对小鼠神经干细胞增殖的影响.分离E14.5小鼠皮层神经干细胞,通过Western blot检测神经干细胞增殖过程中磷酸化ERK1/2的表达情况,以及不同浓度PD98059处理对神经干细胞ERK1/2磷酸化及神经球形成的影响,并用CCK-8法检测PD98059对神经干细胞增殖的影响.结果显示:ERK1/2在体外培养的神经下细胞增殖过程中被激活;PD98059显著抑制ERK1/2磷酸化及神经干细胞的成球率,且存在剂量效应依赖关系;加入PD98059后神经干细胞的生长被抑制.以上结果表明,ERK1/2在小鼠神经干细胞增殖中具有重要的作用,阻断ERK1/2信号通路后可抑制神经干细胞的增殖.     

大鼠钠泵α2亚单位M1～M2膜外区多肽体外活性鉴定

本文旨在研究含大鼠钠泵α2亚单位M1～M2膜外区的多肽片段(peptide contmning rat sodium pump α2 subunit M1-M21extramembrane fragment,RES2衍生物)是否具有与内源性钠泵抑制因子结合以及改善钠泵α亚单位活性的作用.采用Fmoc固相合成法合成多肽(Leu-Ala-Ala-Met-Glu-Asp-Glu-Pro-Ser-Asn-Asp-Asn-Gly-Gly-Gly-Ser),产物经高效液相色谱技术纯化,并进行质谱分析.采用放射性配体.受体结合法检测其与哇巴因的结合能力,进而采用人红细胞86Rb摄取实验检测其生物学活性.结果显示,RES2衍生物与3H-哇巴因具有一定的结合能力,其平衡解离常数(Kd)为38.46 nmol/L,IC50为6.353nmol/L.RES2衍生物可以阻断哇巴因对红细胞膜Na ,K -ATPase的抑制作用,使红细胞86Rb摄取率从38.53%上升到83.69%左右,并呈一定的剂量依赖关系.因此,RES2衍生物不仅具有体外结合活性,而且具有改善钠泵活性的生物学效应,为其成为有效的抗高血压药物提供科学依据.     

硫化氢对大鼠心肌缺血/再灌注损伤的保护作用及其对c-Fos蛋白表达的影响

为探讨硫化氢(hydrogen sulfide,H2S)对大鼠心肌缺血,再灌注(ischemia/reperfusion,I/R)损伤的保护作用及机制,雄性Sprague-Dawley大鼠被随机分为对照组(假手术组)、I/R组、2.8μmol/kg体重NaHS干预组、14 μmol/kg体重NaHS干预组.结扎冠状动脉前降支30 min后,松扎再灌注60 min,心电图Ⅱ导联检测和TTC染色测定心肌梗死面积评价制作的心肌I/R模型:测定血浆中H2S浓度变化;监测血流动力学指标(LVSP,LV±dp/dtmax);HE染色和透射电镜观察心肌形态学改变;免疫组织化学方法测定心肌组织中c-Fos蛋白表达.结果显示:心肌I/R后血浆中H2S浓度明显低于对照组[(30.32±5.26)vs(58.28±7.86)μmol/L,P<0.05]:2.8和14μmol/kg体重NaHS均可显著改善I/R引起的心功能改变,且14μmol/kg体重NaHS较2.8 μmol/kg体重NaHS作用强;14 μmol/kg体重NaHS明显减轻心肌形态学及超微结构损伤,同时降低大鼠I/R心肌组织中c-Fos蛋白表达(0.20±0.06vs0.32±0.10,P<0.05).以上结果提示,H2S对大鼠心肌的I/R损伤有保护作用,这可能与其降低c-Fos蛋白表达有关.     

白藜芦醇甙对大鼠心脏缺血/再灌注损伤的保护作用

本文利用冠脉结扎/放松方法和Langendorff灌注技术,建立在体和离体大鼠心脏缺血/再灌注(ischemia/reperfusion,I/R)损伤模型,探讨白藜芦醇甙(polydatin)对大鼠I/R心肌损伤的保护作用及其机制.观察白藜芦醇甙对缺血和再灌注心律失常、心肌梗死面积、心脏收缩功能、心肌超氧化物歧化酶(superoxide dismutase,SOD)活性、丙二醛(malondialdehyde,MDA)含量、NO含量以及一氧化氮合酶(nitric oxide synthase,NOS)活性的影响.结果显示:与对照组相比,白藜芦醇甙组大鼠缺血和再灌注心律失常明显降低(P<0.05,P<0.01);心肌梗死面积显著减少(P相似文献   

TRPV4在渗透压对大鼠心肌收缩性影响中的作用

本文旨在探讨低渗和高渗内环境对心肌收缩性的影响及机制.取Sprague-Dawley(SD)大鼠左心室乳头状肌,在电刺激引起兴奋的条件下,分别记录在低渗、等渗和高渗灌流液中肌条的收缩力;同样条件下观察在低渗、等渗和高渗灌流液中加入渗透压敏感蛋白瞬时感受器电位离子通道家族香草素受体亚家族IV型(transient receptor potential vanilloid 4,TRPV4)的拮抗剂和激动剂后肌条收缩力的变化.结果显示:(1)与等渗(310 mOsm/L)时心肌收缩力相比,渗透压为290、270和230 mOsm/L时心肌收缩力分别增加11.5%、21.5%、25.O%(P<0.05);渗透压为350、370、390 mOsm/L时心肌收缩力分别降低16.0%、23.7%、55.2%(P<0.05).(2)在低渗液(270 mOsm/L)中加入TRPV4拮抗剂钌红(ruthenium red,RR),低渗对心肌收缩力的增强作用被抑制36%(P<0.01);在高渗液(390 mOsm/L)中加入RR,高渗对心肌收缩力的抑制作用增加56.1%(P<0.01).(3)在等渗液中(310 mOsm/L)加入TRPV4激动剂4-α-佛波醇-12,13-二癸酸(4-α-phorbol-12,13-didecanoate,4 α-PDD),心肌收缩力没有改变;在高渗液中(390 mOsm/L)加入4α-PDD,高渗对心肌收缩力的抑制作用增加27.1%(P<0.01).以上结果提示,TRPV4参与渗透压引起的心肌收缩力变化.