A measure for spatial heterogeneity of vegetation in the Center of Inner Mongolia

This study surveyed and analyzed the vegetation heterogeneity in the Center of Inner Mongolia (CIM) by a new method based on the beta-binomial distribution for each kind of vegetation. Of the 190 large quadrats of 5 mm × 5 mm (representing an area of 50 km × 50 km) (referred to as L-quadrats hereafter) were extracted from about an area of 475,000 km2. Each L-quadrat was divided into four small quadrats (S-quadrat) of 2.5 mm × 2.5 mm (equivalent to 25 km × 25 km) and the frequency of occurrence of each type of the vegetations was recorded in each small quadrate. The weighted average heterogeneity from all of the vegetations composing a landscape provides a measure at landscape level to determine the spatial intricateness of landscape composition. Our results indicated that each vegetation has its own distribution pattern; and the degree of heterogeneity is different from one kind of vegetation to the other. The results proved that the beta-binomial distribution can be very useful for analyzing vegetation landscapes.     

Influence of solution concentration and temperature on the dissolution process and the internal structure of glauberite

Although transport in porous media under the influence of chemistry and temperature is a common phenomenon, the dissolution and internal structure evolution of glauberite during in-situ mining have been unique and challenging. This uniqueness indicates the complexity of mineral dissolutions, whereas the challenge represents the characterization of pore development and evolution during the dissolution processes. To investigate the microstructure development of glauberite under the influence of chemistry and temperature, experimental studies were performed with fine cuboid specimens of 4 mm×4 mm×9 mm soaked in solutions of different concentrations (fresh water, half-saturated, and saturated brine). The evolutions of internal structures were monitored through a micro computed tomography system. The statistical analysis indicated that the concentration and temperature of solutions significantly influenced the evolutions of pore size, porosity, and specific surface area of glauberite. The results showed that the increase in the rates of pore size, porosity, and specific surface area declined with time when glauberite was saturated in fresh water. The main reason for pore parameter variation is the differential concentration of solution. However, in the half-saturated and saturated solutions, the increase in rate increased with time. These observations suggest that the chloride ions contained in the saline solution could facilitate the dissolution of glauberite, whereas the existence of salt effect could contribute to the dissolution of calcium sulfate. Compared with the results at 20℃ and 65℃, the studied parameters of glauberite have dramatically decreased when the mineral was soaked in the solutions at high temperature (95℃). This function was most striking in fresh water. The dissolution of glauberite soaked in fresh water or half-saturated brine solution was conditioned by the temperature and solution concentration. However, the dissolution of glauberite was less influenced by temperature at high concentrations. These findings may feature significant implication for the effective recovery of mineral resources by in-situ solution mining method.     

苦皮素A标准品的制备研究

为测定苦皮藤素产品中苦皮素A的含量,以控制苦皮藤素产品的质量,将苦皮藤根皮的95%乙醇提取物用硅胶柱分离、活性碳脱色后,利用制备高效液相色谱法制得苦皮素A的标准品,纯度达98.5%.制备型色谱柱为Shimpack PREP-ODS(20 mm×250 mm,15μm;)流动相为甲醇-水(体积比为703∶0)溶液;流速为15 ml/min;检测波长为232 nm;柱温为25℃.用13CNMR鉴定苦皮素A的结构.此方法得到的苦皮素A产品的纯度高,可用作分析方法的对照品.     

不同试模对灌浆料早期抗压强度影响试验研究

采用统一的原材料、配合比、养护条件制作了3种不同试模、6个不同龄期的216个水泥基灌浆料试块,在相同的加载条件下进行了抗压强度测定,研究了在6个不同龄期下,不同试模对水泥基灌浆料试块早期抗压强度的影响及不同试模下抗压强度换算系数.得出了第Ⅲ类水泥基灌浆料在标准养护条件下尺寸为40 mm×40 mm×160 mm棱柱体标准试块与尺寸为150 mm×150 mm×150 mm立方体非标准试块的早期抗压强度换算系数和第Ⅳ类水泥基灌浆料在标准养护条件下尺寸为100 mm×100 mm×100 mm立方体标准试块与尺寸为150 mm×150 mm×150 mm立方体非标准试块的早期抗压强度换算系数.分析各个早期强度换算系数变化规律,得出可供实际工程参考的换算系数.     

聚焦超声消融肝癌时大血管位置对热场分布的影响

采用有限元方法研究了聚焦超声消融肝脏肿瘤时，大血管存在于肿瘤附近不同位置对温度分布以及热剂量分布的影响．建立基于大血管对流效应的生物传热模型，基于不同的加热方案进行3-D温度瞬态仿真．仿真针对四种情况进行计算：模型中无血管，血管分别距离肿瘤1mm、2mm、3mm．仿真结果表明使用聚焦超声进行快速加热可以使能量集中在目标治疗区域．但是当肿瘤组织的近距离内（1mm）存在大血管且加热时间较长时（〉2s），肿瘤组织靠近血管的边界部分仍然会受到大血管冷却效应的影响，这种影响会导致肿瘤治疗不彻底．当肿瘤距离大血管3ram以上时，大血管在聚焦超声治疗中的冷却效应不再明显．     

Information extraction and CT reconstruction of liver images based on diffraction enhanced imaging

X-ray phase-contrast imaging (PCI) is a new emerging imaging technique that generates a high spatial resolution and high contrast of biological soft tissues compared to conventional radiography. Herein a biomedical application of diffraction enhanced imaging (DEI) is presented. As one of the PCI methods, DEI derives contrast from many different kinds of sample information, such as the sample's X-ray absorption, refraction gradient and ultra-small-angle X-ray scattering (USAXS) properties, and the sample information is expressed by three parametric images. Combined with computed tomography (CT), DEI-CT can produce 3D volumetric images of the sample and can be used for investigating micro-structures of biomedical samples. Our DEI experiments for liver samples were implemented at the topography station of Beijing Synchrotron Radiation Facility (BSRF). The results show that by using our provided information extraction method and DEI-CT reconstruction approach, the obtained parametric images clearly display the inner structures of liver tissues and the morphology of blood vessels. Furthermore, the reconstructed 3D view of the liver blood vessels exhibits the micro blood vessels whose minimum diameter is on the order of about tens of microns, much better than its conventional CT reconstruction at a millimeter resolution. In conclusion, both the information extraction method and DEI-CT have the potential for use in biomedical micro-structures analysis.     

MRIgHIFU治疗的热损伤阈值研究

研究基于磁共振T-Map的等效热剂量积分法监控高强度聚焦超声治疗的可行性.并筛选出高强度聚焦超声损伤组织的热剂量阈值.运用磁共振导航高强度聚焦超声治疗系统,使用1 MHz、焦距为150 mm、直径150 mm的聚焦超声换能器,用不同辐照声功率和辐照时间定点辐照深度为20 mm的新鲜离体牛肝脏,辐照过程中用磁共振的测温序列采集各体素随时间变化的温度值并计算各体素的Eq43值,比较计算结果与发生凝固性坏死的Eq43参考阈值,判断该体素是否发生坏死,得到发生凝固性坏死的热剂量区域轮廓和面积.辐照结束后沿凝固性坏死最大面剖开牛肝组织,测量凝固性坏死的面积.选择不同的Eq43参考阈值,并将热剂量计算得到的坏死面积与实际坏死面积进行比较.筛选出离体牛肝组织发生凝固性坏死的最佳热剂量参考阈值.结果表明,基于磁共振T-Map的等效热剂量积分法得到的凝固性坏死的面积值能很好地反应实际发生凝固性坏死的情况,当Eq43参考阈值选为31.2 min时,各辐照声功率和辐照时间下两者大小均无统计学差异.热剂量法为HIFU治疗提供了一种新的判断凝固性坏死发生的方法,这种方法可以实时地反馈控制超声辐照剂量,提高了治疗的安全性和有效性.     

污泥厚度和风速对污泥常温干燥的影响及干燥模型分析

为了研究污泥在常温下的干燥特性,采用自制的污泥干燥装置对城市脱水污泥进行常温干燥实验。研究了不同厚度(10、20、30 mm)和不同风速(0、1、3 m·s~(-1))条件下污泥含水率随时间变化的规律,并用常见的干燥模型对污泥常温干燥过程进行拟合。结果表明:常温条件下,10 mm厚度污泥的干燥速率均高于20 mm和30 mm厚度污泥的干燥速率,并且在风速较低时,降低污泥厚度对缩短干燥时间的效果更加显著;污泥厚度不同,风速对污泥干燥的影响作用不同,对于10 mm厚度的污泥,增加风速可显著缩短干燥时间,而对于20 mm和30 mm厚度的污泥,风速需增加到一定数值(如3 m·s~(-1))时,才能显著缩短干燥时间;Logarithmic模型更适合描述污泥在常温条件下的干燥,干燥过程中的有效扩散系数为1.73×10~(-9)~1.38×10~(-8)m~2·s~(-1)。     

Room-temperature NH3 sensors with high sensitivity and short response/recovery times

Micro-sensors are fabricated by co-electrospin- ning In203 and SnO2 nanofibers on the substrates of SiO2/Si with interdigitated Pt signal electrodes. The total sensor area is 1.36 mmx 0.55 mm and the active area is only 0.63 mmx 0.55 ram. Excellent NH3 sensing properties are obtained based on the sensors at room temperature. The sensitivity is at most 28 when the sensors are exposed to NH3 of 10 ppm. The response time is 8 s or so and the recovery time is nearly 2 s. Not only fine selectivity, but also long- time stability is obtained. The results not only demonstrate the obtained micro-sensors are very promising devices for NH3 detection, but also show a possible route for large-scale NH3 sensor fabrication at the industrial level.     

小流域中-低频泥石流与山洪输沙比例的讨论:以金沙江支流海子沟为例

泥石流山洪输沙比是工程防治设计的重要参数。本文以金沙江支流海子沟为例,调访了近115a的泥石流活动历史,查明了1996年一次最大规模泥石流运动参数,采用雨洪法计算了不同的泥石流发生频率下泥石流的流量、总量。通过对1899年至今海子沟堰塞坝泥沙淤积的测定,得出海子沟流域每年泥沙淤积量为1.23×10~5 m~3,总输沙量为1.42×107 m~3,流域平均剥蚀速率为1.5mm/a。由不同泥石流频率下海子沟泥石流的固体物质总量,计算出自1963年以来海子沟泥石流输沙量为1.67×10~6 m~3,而此期间山洪泥石流的总输沙量为6.65×10~6 m~3,由此确定海子沟泥石流的输沙量占山洪泥石流输沙总量的25%。而官坝河泥石流、白龙江流域泥石流、蒋家沟泥石流输沙量分别占总输沙量的29.5%、62.9%、99%,泥石流输沙量随着泥石流频率的增加而增加。高频率泥石流工程拦挡仅考虑泥石流输沙量;类似白龙江流域松散固体物质丰富的半干旱气候区泥石流防治拦挡工程需考虑山洪输沙量;而类似官坝河、海子沟中等频率的泥石流沟,需更多考虑山洪输沙量。     

利用成体干细胞体外小口径血管的构建

设计了一套血管生物反应器系统,采用有限元的方法对组织工程小血管托架材料进行了分析,从而开发完成了一套用于构建直径为2 mm的小血管托架;通过收集人的原代骨髓基质干细胞(hBMSCs)和脂肪基质干细胞(ADSCs)进行体外扩增和培养,并选用第3代细胞与聚羟基乙酸酯(PGA)复合后置于血管生物反应器中动态培养;在生物反应器中动态培养4周后,对材料复合物进行取材,分别进行大体观察、HE染色和扫描电镜等指标检测.结果表明:血管色泽明亮,有一定的弹性,细胞分泌的胶原基质排列较规则,免疫组化结果表明血管含有平滑肌弹性肌动蛋白的成分.说明改进的血管生物反应器能模拟血管的力学环境,并能利用人骨髓间充质干细胞扣脂肪基质干细胞成功构建组织工程小血管组织.     

辽宁北票龙骨组织中类似血细胞结构的研究

在我国辽宁北票下白垩统义县组下部地层中出土的北票龙(Beipiaosaurus inexpectus)化石由部分椎骨和肢骨碎片构成,其中保存有血管和类似血细胞的结构。在肢骨周围有褐色细丝状的皮肤衍生物的印痕。细丝状皮肤衍生物无分枝,大约0.1mm宽,50～60mm长。在光学显微镜下观察到其肱骨的纵切面上有褐色血管结构,一些管腔中有褐色小圆球,它们沿着管腔分布。这些小圆球的形状和大小显示它们有可能是恐龙血细胞的遗迹。另外,图像分析法结果显示北票龙骨组织有较高的血管密度,表示它具有较高的新陈代谢率。从骨组织特征及作为体表隔热层的细丝状皮肤衍生物的存在来看,北票龙可能为恒温动物。     

Live birth after ovarian tissue transplant

Radiation and high-dose chemotherapy may render women with cancer prematurely sterile, a side-effect that would be avoided if ovarian tissue that had been removed before treatment could be made to function afterwards. Live offspring have been produced from transplanted ovarian tissue in mice and sheep but not in monkeys or humans, although sex steroid hormones are still secreted. Here we describe the successful transplantation of fresh ovarian tissue to a different site in a monkey, which has led to the birth of a healthy female after oocyte production, fertilization and transfer to a surrogate mother. The ectopically grafted tissue functions without surgical connection to major blood vessels and sets the stage for the transplantation of cryopreserved ovarian tissue in humans.     

胶原酶灌注部分肝脏方法分离肝主质细胞

本文报导一种分离哺乳类正常肝细胞的新方法,其要点是精确安排操作的程序,在灌注前结扎肝脏的左叶和正中叶,使灌注液只在余下的1/3肝脏内流动。本方法快速、稳定,能在2小时内从大鼠的1/3肝脏(2—3克肝组织)分离出1—1.5×10~7个和肝主质细胞,存活率在95%以上。酶液(0.05%胶原酶)的用量为20～25ml,在同类实验中是最少的。     

超声造影观察小鼠两种皮下移植瘤的血管生成

目的 应用高频小动物超声观察人 BT-B 膀胱癌和人 Huh7 肝癌两种皮下移植瘤的血管生成情况,探讨超声 造影评价肿瘤血管生成情况的价值。 方法 采用皮下注射建立人 BT-B 膀胱癌和人 Huh7 肝癌两种皮下移植瘤模 型,采用高频小动物超声成像系统的多种超声模式观察两种肿瘤内部结构和血管特性;采用探头式活体激光共聚 焦观察肿瘤的小血管数量和大小;采用免疫组化法观察肿瘤的血管标志物 CD31 表达,计算微血管密度。 结果 两 组裸鼠均成功荷瘤。 B 超模式显示 Huh7 与 BT-B 皮下瘤均为不均质低回声结节;彩色多普勒模式及频谱多普勒模 式显示 BT-B 皮下瘤血流信号和血流速度多于 Huh7 皮下瘤;超声造影显示 Huh7 肝癌组血管分布紊乱,BT-B 膀胱 癌组血管分布呈“分支状” ,与探头式活体激光共聚焦结果及病理结果一致。 超声造影参数峰值强度( PI) 与 MVD 呈正相关( r = 0. 844,P<0. 05) 。 结论 超声造影可以更好地显示肿瘤血管的分布情况,且 PI 与病理 MVD 呈正相 关,可提示肿瘤血管的增殖情况,可以作为无创评价肿瘤血管生成的可靠方法。     

Calculation of the intracellular elastic modulus based on an atomic force microscope micro-cutting system

Better understanding of variations in the mechanical properties of cancer cells could help to provide novel solutions for the diagnosis,prevention,and treatment of cancers.We therefore developed a calculation model of the intracellular elastic modulus based on the contact pressure between the silicon tip of an atomic force microscope and the target cells,and cutting depth.Ovarian cells(UACC-1598) and colon cancer cells(NCI-H716) were cut into sequential layers using an atomic force microscope silicon tip.The cutting area on the cells was 8μm×8μm,and the loading force acting on the cells was increased from 17.523 to 32.126μN.The elastic modulus distribution was measured after each cutting process.There were significant differences in contact pressure and cutting depth between different cells under the same loading force,which could be attributed to differences in their intrinsic structures and mechanical properties.The differences between the average elastic modulus and surface elastic modulus for UACC-1598 and NCI-H716 cells were 0.288±0.08 kPa and 0.376±0.16 kPa,respectively.These results demonstrate that this micro-cutting method can be used to measure intracellular mechanical properties,which could in turn provide a more accurate experimental basis for the development of novel methods for the diagnosis and treatment of various diseases.     

Macrosegregation and the underlying mechanism in Ti-6.5Al-1.0Cr-0.5Fe-6.0Mo-3.0Sn-4.0Zr alloy

A novel method for the analysis of composition distribution of titanium alloys over a large area(64 mm × 72 mm) was investigated by exploring the original position statistic distribution based on spark spectrum(OPA-SS) in Ti-6.5 Al-1.0 Cr-0.5 Fe-6.0 Mo-3.0-Sn-4.0 Zr titanium alloy. The results showed that OPA-SS could characterize the distribution of elements in different positions on the titanium alloy. The macrosegregation of Sn was the most pronounced, with a statistic segregation degree higher than 18%; the macrosegregation of Mo followed with a statistic segregation degree of 10%; the macrosegregation of Al and Fe was relatively milder,lower than 8%. The main reason for the macrosegregation state of the as-cast Ti-6.5 Al-1.0 Cr-0.5 Fe-6.0 Mo-3.0 Sn-4.0 Zr alloy can be the solute redistribution during liquid solidification and the diffusion rate of each element in the solid phase.     

达旦黄与牛血清白蛋白作用的光谱特性

以达旦黄为探针,应用荧光及紫外光谱法研究达旦黄(TY)与牛血清白蛋白(BSA)分子间的结合反应,测定了不同温度下的结合常数和结合位点数.实验表明:TY对BSA内源荧光的猝灭机理为静态猝灭,作用力类型为疏水作用.根据Frster能量转移理论,求得不同温度(16 ,30 ,40 ℃)下的能量转移效率E分别为0.419 6,0.401 9,0.386 5,作用距离r分别为3.05,3.04,3.10 nm.BSA存在猝灭TY的荧光,以此为基础建立了测定BSA的方法,线性范围:3×10-7～2×10-5 mol/L,检出限:9.07×10-7 mol/L,相对标准偏差:RSD=1.7%.     

酶法改性柚皮苷的高效液相色谱分离及结构表征

在叔戊醇有机介质中,用固定化脂肪酶Novozym 435®催化柚皮苷和棕榈酸发生酯化反应,在柚皮苷分子上引入亲脂性的棕榈酰基团。采用制备高效液相色谱对改性柚皮苷进行分离纯化,优化的色谱条件为：色谱柱：C18柱（21.5×250 mm）;流动相：甲醇;流速：20 mL/min;进样浓度：30 mg/mL;进样体积3 mL。产物经红外光谱、质谱证实为柚皮苷棕榈酸单酯,核磁共振碳谱分析表明,酰基化选择性地发生在柚皮苷的葡萄糖基的6′′-羟基位上。并对区域选择性反应机理进行了探讨。     

晶体硅太阳电池应力的理论分析

光伏组件的电池层为一离散分布的不连续夹层. 针对组件中晶体硅电池片的受力特点导出了电池片的应力场和位移场，并对面板尺寸为1 580 mm × 808 mm的单晶硅标准组件在风荷载作用下晶体硅电池片的应力进行了计算和分析，考虑了风压及EVA胶膜的剪切模量变化对应力的影响. 计算结果与有限元结果进行了比较，并对比了125 mm × 125 mm和156 mm × 156 mm两种规格电池片的应力. 结果表明，理论结果与有限元结果符合很好，应力最大值出现在电池片的中点并随着EVA胶膜剪切模量的增加呈非线性增大；增大电池片的尺寸将引起应力的显著增加.