显微结构观察快速鉴定Lolium属的籽实

本研究通过对毒麦属的毒麦与其变种长芒毒麦、田毒麦及其近似种亚麻毒麦、多花黑麦草、黑麦草、波斯黑麦草、瑞士黑麦草等 8个种的种子进行显微组织细胞结构解剖 ,观察、比较和综合分析各个种子内部盾胚的形态大小、上皮细胞和糊粉层细胞的形态结构的异同点。为口岸杂草检验检疫的快速准确鉴定提供科学依据。

黄瓜矮生突变体C1056的茎解剖结构及其生理特性分析

该研究以黄瓜矮生突变体C1056和野生型CCMC为材料,对其主要生理特性、叶绿体超微结构以及茎显微结构进行了观察、测定和比较分析,以探讨黄瓜株高调控机理并挖掘新的矮化种质,为黄瓜的矮化育种提供依据。结果显示:(1)突变体C1056的株高较野生型极显著变矮,且叶色加深、叶脉加粗、叶尖内卷、叶片皱缩,但茎粗、节间数与野生型无显著差异,而节间长度极显著低于野生型。(2)茎横切显微结构显示,突变体的维管束数量与野生型无显著差异,但导管直径缩小;纵切结果显示,突变体茎节间细胞长度变短,细胞变小,细胞数目略有补偿。(3)与野生型相比,突变体的叶绿素和类胡萝卜素含量均有不同程度的下降,叶绿素/类胡萝卜素和叶绿素a/b的比值明显增高。(4)突变体叶绿素荧光各参数与野生型相比无明显变化;突变体的净光合速率较野生型降低8%,气孔导度、蒸腾速率较野生型分别提高15%和10%,但差异均不显著,而胞间CO2浓度显著高于野生型。(5)透射电镜观察结果发现,与野生型相比,突变体的叶肉细胞比较小,叶绿体所占细胞面积明增大,且叶绿体形状为半圆形和纺锤形,部分非正常结构的叶绿体的大部分基质、基粒片层未完全分化且不清晰,垛叠不整齐。研究表明,黄瓜矮生突变体C1056的矮化主要因其节间长度缩短以及细胞变小所致,且突变体的叶绿体结构受到一定程度的影响,但并未明显影响其光合能力。

Obsevation for Epidermal Ultrastructure of Nostoc sphaeroides Kutzing under Scanning Electron Microscope

[Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [ Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions. [ Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing.

Seventy Years’“Micropedology”1938-2008:The Past and Future

Although the first microscopic observations on soils date already from the beginning of the twentieth century, the publication of Kubiena＇s book ＂Micropedology＂ in 1937 is considered as the beginning of this new scientific discipline. This first system for micromorphological descriptions of soils is considered as morphoanalytical, analysing the fabric according to pure morphological criteria. In a second period Kuniena used a morphogenetic approach, directly relating the global observed fabric to genetic soil horizons. This system, mainly limited to European soils, was in general use till the early nineteen-seventies. End of the nineteen-fifties non- genetic soil classification systems were developed （e.g. USDA）. This trend prompted R. Brewer to publish in 1964 a new morphoanalytical system for fabric analysis, used till the end of last century. Because of some inconsistencies in this approach, a working group of the ISSS published in 1985 a new set of morphoanalytical concepts and associated terminology （Bullock et al.）, in 2003 adapted and extended by Stoops. Several morphosynthetic systems, expressing a complete soil microfabric in a single （compound） term have been proposed, but none was really successful. In 1967 Kubiena introduced the term ＂micromorphometry＂ to name a new branch of micromorphology quantifying the soil fabric, mainly evaluating changes in porosity and structure resulting from soil management. The necessity of dearly defined concepts and terms for fabric analysis of soils and regoliths, even as a need for standardisation of quantitative methods, are discussed in the conclusions.

Development of a pentaethylenehexamine-modified solid support adsorbent for CO_2 capture from model flue gas

A novel solid support adsorbent for CO2capture was developed by loading pentaethylenehexamine(PEHA)on commercially available mesoporous molecular sieve MCM-41 using wet impregnation method.MCM-41 samples before and after PEHA loading were characterized by X-ray powder diffraction,N2adsorption/desorption,thermal gravimetric analysis and scanning electron microscope to investigate the textural and thermo-physical properties.CO2adsorption performance was evaluated in a fixed bed adsorption system.Results indicated that the structure of MCM-41 was preserved after loading PEHA.Surface area and total pore volume of PEHA loaded MCM-41 decreased with the increase of loading.The working adsorption capacity of CO2could be significantly improved at 60%of PEHA loading and 75°C.The effect of the height of adsorbent bed was investigated and the best working adsorption capacity for MCM-41-PEHA-60 reached 165 mg·(g adsorbent)-1at 75°C.Adsorption/desorption circle showed that the CO2working adsorption capacity of MCM-41-PEHA kept stable.

In situ observation of surface structures of cardiovascular endothelial cells with atomic force microscope

Objective To observe the surface structures of cardiovascular endothelial cells in situ with atomic force microscope （AFM）. Methods Fresh aorta and aortic valve were dissected from 10 healthy male New Zealand white rabbits. Before fixed in 1% formaldehyde, the fresh tissues were washed in the buffer phosphate solution. Under general microscope, the fixed aorta or valve was spread on the double side stick tape which had already been stuck on the glass slide. The intima of aorta or the aorta side of valve was towards upside, Then the specimen was dried under 37 degrees centigrade in an attemperator and was washed with pure water. After dried again, the specimen was loaded on the platform ofNanoScope Ⅲa AFM and was scanned in tapping mode with the scanning speed of 0.5 HZ. Results The surface structures of endothelial cell on the fixed and dried tissue could be observed clearly in situ with AFM. aortic endothelial cells were large, branched and arranged sparsely and parallel to the direction of blood flow, whereas endothelial cells on aorta valve surface were small, less branched and arranged intensively and vertical to the direction of blood flow. When the scanning range was dwindled, granular ultra-structures could be observed on the surface of endothelial cells, and, as the scanning range was dwindled further, fissure and convolution could be seen on the surface of granules from aortic endothelial cells. Centre cavity and surrounding swelling volcano-like structure could be seen on the surface of granules from endothelial cells of aortic valve. Conclusions It＇s feasible to observe the surface ultra-structures of cardiovascular endothelial cells in situ with AFM and morphological information provided by AFM might be of clinical value in future histopathological diagnosis（JGeriatr Cardiol2009; 6：178-181）.

A Study on the Wing Characteristics of Flies

This paper is concerned with the aerodynamic functions of fly wings. The free and tethered flight analyses were performed by using a digital high-speed video camera system. A liquid droplet impacting with a wing surface of fly was conducted to examine the wing characteristics. Microscopic observation of fly＇s wings were also conducted by using a laser beam microscope. The results of a series of observation and measurement revealed the flight characteristics of flies, such as the wing tip velocity, wing path, wing flexibility, wing structure, resistance to rain drops, and so forth.

以荧光细胞内器官标示法区别犬之传染性花柳性肿瘤及淋巴瘤

绪言传染性花柳性肿瘤发生在世界各地,尤其是热带、亚热带地区是一种很普遍的犬只疾病,肿瘤发生在母犬的阴道、会阴,或围绕在尿道孔,临床上有恶臭之血样的阴道渗出物,在公犬可见于龟头,尿道球腺、阴茎等处,

Effects of Silver Nanoparticles on Soil Microbial Communities and Bacterial Nitrification in Suburban Vegetable Soils

Silver nanoparticles （AgNPs） are widely used antimicrobial compounds; however, they may pose a threat to non-targeted bacteria in the environment. In this study high-throughput sequencing was used to investigate the effects of different concentrations of AgNPs （10, 50, and 100 mg kg-1） on soil microbial community structure during short-term （7 d） exposure. The amounts of Acidobacteria, Actinobacteria, Cyanobacteria, and Nitrospirae significantly decreased with increasing AgNP concentration; meanwhile, several other phyla （e.g., Proteobacteria and Planctomycetes） increased and dominated. Nitrosomonas europaea, a well-characterized ammonia- oxidizing bacterium, was used to study the sensitivity of bacteria to AgNPs and ionic silver （Ag＋）. Flow cytometry was used to monitor the toxicity of low （1 mg L-l）, middle （10 mg L-l）, and high concentrations （20 mg L-1） of AgNPs, as well as Ag＋ （1 mg L-1） released into the medium from 20 mg L-1 concentration of AgNPs, towards N. europaea. After 12 h of exposure, the survival rate of N. europaea treated with 1 mg L-1 Ag＋ was significantly lower than those treated with low （1 mg L-1） and middle concentrations （10 mg L-1） of AgNPs, but the survival rate in the treatment with high concentration （20 mg L-1） of AgNPs was much lower. Additionally, necrosis rates were higher in the treatment with 20 mg L-1 AgNPs. Electron microscopy showed that Ag＋ caused serious damage to the cell wall of N. europaea, disintegrated the nucleoids, and condensed next to the cell membrane; however, dissolved Ag＋ is only one of the antibacterial mechanisms of AgNPs.

Ultrastructural observation on sterilization of melittin

The effects of melittin on growth and bacteriostasis of four pathogens were extensively investigated using scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results indicated that the melittin had a marked bacteriostatic effect on the four pathogenic bacteria.Among these,E.cacotowora was influenced most powerfully and quickly,the yeast and F.fulva were the second,and the S.aureus was inhibited by a low concentration but was killed by a high concentration.It was observed in the experiments that melittin killed pathogenic bacteria in three ways.One was by pore formation.After integrating melittin into the plasma membrane,a vacuole was formed then penetrated,resulting in bacterial content leakage.The vacuole also experienced plasmolysis and the growing cavity destroyed the membrane.A third effect was the formation of vacuoles in the cells which induced the pycnosis of the cytoplasm resulting in a cell death.The mechanism of melittin bacteriostasis was the result of integrating melittin with phospholipod double layers of the plasmalemma and the endomembranes.

Relationship between the parent charge transfer gap and maximum transition temperature in cuprates

One of the biggest puzzles concerning the cup- rate high temperature superconductors is what determines the maximum transition temperature （Tc,max）, which varies from less than 30 to above 130 K in different compounds. Despite this dramatic variation, a robust trend is that within each family, the double-layer compound always has higher Tc,max than the single-layer counterpart. Here we use scanning tunneling microscopy to investigate the electronic structure of four cuprate parent compounds belonging to two different families. We find that within each family, the double layer compound has a much smaller charge transfer gap size （ACT）, indicating a clear anticorrelation between AcT and Tc,max. These results suggest that the charge transfer gap plays a key role in the superconducting physics of cuprates, which shed important new light on the high To mechanism from doped Mott insulator perspective.

Erbium germanosilicide Ohmic contacts on Si_(1-x)Ge_x(x=0-0.3) substrates

We have studied erbium germanosilicide (ErSiGe) Ohmic contacts on n-type Si_(1-x)Ge_x substrates with differing Ge concentrations (0≤x≤0.3).Thin layers of Ti (20 nm)/Er (20 nm) were deposited on Si_(1-x)Ge_x substrates and then post-annealed at 600°C for 60 s to form a stable ErSiGe film.The structures of the ErSiGe films and ErSiGe/Si_(1-x)Ge_x interfaces were characterized by Transmission Electron Microscopy measurements (TEM).The TEM images showed that the thicknesses of ErSiGe films and the Si_(1-x)Ge_x substrates were about 60 and 50 nm,respectively.The ErSiGe/Si_(1-x)Ge_x structure had a smooth interface.Moreover,no agglomeration or Ge segregation was observed.The contact resistivity of the ErSiGe/Si_(1-x)Ge_x structures was measured by the specially designed four-terminal Kelvin structures.When the Ge concentration of Si_(1-x)Ge_x substrates increased from 10% to 30%,the specific contact resistivity (c) slightly decreased from 9.0×10 7 ·cm 2 to 7.4×10 7 ·cm 2,indicating that the Ge concentration is not the main effect on the c of the ErSiGe/Si_(1-x)Ge_x Ohmic contacts.