OBSERVATION OF THE EFFECT OF S－（－）USNIC ACID SODIUM ON TRICHOMONAS VAGINALIS BY TRANSMISSION ELECTRON MICROSCOPE

This paper reports the ultrastructural changes of trichomonas vaginaiis (T. vag. ) under the action of s-(-)usnic acid sodium in vitro. These changes can be shown by the following results:At first, the degranulation of the rough endoplasmic reticulum (RER) took place, the polyribosomes disaggregated. And then, the Golgi complex and the endoplasmic reticulum dilated. The cytoplasmic matrix presented and inhomogeneous apperance. Finally, the biomembrane loosed and fractured.The cell nuclei presented the karyorrhexis.

Characterization of Li-rich layered oxides by using transmission electron microscope

Lithium-rich layered oxides(LrLOs) deliver extremely high specific capacities and are considered to be promising candidates for electric vehicle and smart grid applications. However, the application of LrLOs needs further understanding of the structural complexity and dynamic evolution of monoclinic and rhombohedral phases, in order to overcome the issues including voltage decay, poor rate capability, initial irreversible capacity loss and etc. The development of aberration correction for the transmission electron microscope and concurrent progress in electron spectroscopy, have fueled rapid progress in the understanding of the mechanism of such issues. New techniques based on the transmission electron microscope are first surveyed, and the applications of these techniques for the study of the structure, migration of transition metal, and the activation of oxygen of LrLOs are then explored in detail, with a particular focus on the mechanism of voltage decay.

Nanoelectronic devices resonant tunnelling diodes grown on InP substrates by molecular beam epitaxy with peak to valley current ratio of 17 at room temperature

This paper reports that InAs/In0.53Ga0.47As/AlAs resonant tunnelling diodes have been grown on InP substrates by molecular beam epitaxy. Peak to valley current ratio of these devices is 17 at 300K. A peak current density of 3kA/cm^2 has been obtained for diodes with AlAs barriers of ten monolayers, and an Ino.53Ga0.47As well of eight monolayers with four monolayers of InAs insert layer. The effects of growth interruption for smoothing potential barrier interfaces have been investigated by high resolution transmission electron microscope.

Electron Micrographic Representations of Mechanisms of Action of Murine Norovirus on ATCC TIB-71 Cells and Level of Gene Expression

Human noroviruses (HuNoV) are the number one cause of viral gastroenteritis worldwide resulting in a significant cause of morbidity and mortality in all age groups. However, despite the medical relevance of HuNoV, effective treatment against norovirus infection is yet to be developed. In this study, we investigated the anti-Noroviral activity of Hibiscus sabdariffa (HS) calyces and Zanthoxylum armatum (ZA) seeds using murine norovirus, a surrogate of human norovirus. The antiviral mechanisms of action were also examined using a gene expression studies and transmission electron microscopy. Our results showed that virus-infected cells were left potentially void of all the cell machineries whereas uninfected cells represent healthy normal and dividing cells. The infected treated cells with extracts showed restoration of the dense cytoplasm, cytoplasmic membrane, and the nucleus. These cells were also associated with the expression of ORF genes. This study demonstrates the antiviral properties of Hibiscus sabdariffa (HS) calyces and Zanthoxylum armatum (ZA) and thus indicates their potential as natural remedies to treat noroviruses.

Bacteriological and electron microscopic examination of primary intrahepatic stones

BACKGROUND: Primary intrahepatic cholelithiasis is usually combined with biliary tract infection. This research was undertaken to investigate the relationship between intrahepatic stones and biliary tract infection. METHODS: Thirty-five bile samples and 30 stones specimens were cultured for bacteria and 12 stones specimens were examined with a scan electron microscope (SEM) or a transmission electron microscope (TEM). RESULT: 94.2% bile samples and 96.7% stones specimens were positive in bacteria culture. Bacteria were found in stones under SEM and TEM. CONCLUSION: Bacteria in stones are associated with the infection of the biliary tract.

Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive for S100 （Schwann cell marker） and glial fibrillary acidic protein （glial cell marker） at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvi- ronment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

Toxic effects of fluoranthene and copper on marine diatom Phaeodactylum tricornutum

To investigate the effects of polycyclic aromatic hydrocarbons (PAHs) and metals on the population reproduction,antioxidative defense system and cell ultrastructure of the marine diatom,fluoranthene and Cu2+ were selected to test their toxicity to Phaeodactylum tricorntum,in the laboratory.The results indicated that both fluoranthene and Cu2+ inhibited population reproduction of P.tricorntum.When the algal cells were exposed to fluoranthene or Cu2+ for 72 h,ultrastructure damage in the cells was observed un...

Localization of AKAP4 and tubulin proteins in sperm with reduced motility

Aim： To perform screening, related to A-kinase anchoring proteins 4 （AKAP4） and tubulin proteins, in spermatozoa with absent or severely reduced motility in order to detect the status of the fibrous sheath and the axonemal structure. Methods： An immunocytochemical study of tubulin, used as a positive control, and AKAP4 was carded out to detect the presence and the distribution of these proteins in different sperm samples. The morphological characteristics of sperm were studied by transmission electron microscope （TEM） and the results were elaborated using a formula reported in previous studies. PCR was carried out on DNA extracted from peripheral blood lymphocytes to analyse partial sequences of the Akap4 and Akap3 genes. Results： Immunolabelling of tubulin and AKAP4 showed different patterns, which led us to divide the patients into groups. In group I, the absence of AKAP4 and tubulin was revealed, although these patients did not show alterations in the Akap4/Akap3 binding site. TEM evaluation highlighted that a high presence of necrosis was associated with total sperm immotility. In group Ⅱ, a regular AKAP4 and tubulin signal was present, although motility was reduced and TEM analysis revealed the presence of immaturity. In group Ⅲ, in which a weak AKAP4 label associated with normal tubulin staining and reduced motility was observed, a severe disorganization of the fibrous sheath was highlighted by TEM. Conclusion： While the role of AKAP4 in sperm motility is unclear, absent or weak AKAP4-1abelling seems to be associated with absent or weak sperm motility.

Rapid Biosynthesis of Silver Nanoparticles Using Cymbopogan Citratus (Lemongrass) and its Antimicrobial Activity

The present study deals with the rapid green synthesis of silver nanoparticles using fresh leaves of Cymbopogan Citratus(Lemongrass). Silver nanoparticles were formed within 8～10 minutes by microwave irradiation using aqueous solution of Ag NO3(1 m M) with fresh leaves extract of Cymbopogan Citratus. The synthesized silver nanoparticles were characterized by using UV-visible spectrophotometer analysis, nanoparticle tracking analyzer, transmission electron microscope and energy dispersive X-ray spectra. The antibacterial activity of these nanoparticles was studied against multiple drug resistant hospital isolates of E.coli, S.aureus,P.mirabilis and hospital isolates of S. typhi, K.pnuemoniae. Also, the antifungal activity of these nanoparticles was studied against C.albicans(hospital isolate) and A.niger(NCIM 616). The synergistic effect of silver nanoparticles along with antibiotics was also studied against multiple drug resistant hospital isolates and found to be effective. The extracellular synthesis of Silver nanoparticles using leaves of Cymbopogan Citratus appears to be rapid and eco-friendly.

Study on the Ultrastructures of Antennal Sensilla in Helicoverpa armigera

The morphology and structures of antennal sensilla of Helicoverpa armigera are observed under scanning and transmission electron microscopes. Antennae of Helicoverpa armigera are made up of scapus, pedicel and flagellum that the latter consists of 70 - 82 segments. The inner side surface of antenna is cat-aphracted and most of the antennal sensilla lie on its outer, upper and lower surfaces. Both the antennae of male and female contain five kinds of antennal sensilla, namely, sensillum trichodeum, sensillum basicon-icum, sensillum chaeticum, ear-shaped sensillum and sensillum coeloconicum, and the kinds, number and distribution of antennal sensilla of both sexes are similar. There are a large number of serrate cuticular processes on antennal surface, especially on the middle and basic parts of antenna. Sensillum trichodeum and sensillum basiconicum, the main chemical odor receptors on antennae of Helicoverpa armigera, consist of cuticular-wall, sheath cells, lymph and dendrites. There are significant differences between the internal structures of the two kinds of sensilla. In sensillum trichodeum, the cuticular-wall is thicker, less lipophilic pore channels and has one or a few dendrites, while in sensillum basiconicum, the cuticular-wall is thinner, abundant lipophilic pore channels and has much more dendrites.

Morphology and electrical conductivity of PACS

Polyaluminium chlorides with sulfate ion(PACS) were prepared by using AlCl 3·6H 2O, Al(SO 4) 3·18H 2O and Na 2CO 3 as raw materials. The effects of basicity ( r ), Al 3+ /SO 4 2- molar ratio and aging time on the morphology of PACS were observed by transmission electrical microscope. The influence of aging time on charge neutralization and coagulation effect of PACS was studied. The effects of basicity ( r ), Al 3+ /SO 4 2- molar ratio and aging time on the electrical conductivity of PACS solution were also investigated. The experimental results show that the degree of polymerization of polyaluminium chloride(PAC) increases when SO 4 2- ion is added. The higher the basicity( r ) and the longer the aging time, the larger the size of polymer PACS. The ability of PACS neutralizing the charge on Kaolinite decreases with the increase of aging time. The electrical conductivity of PACS solution(the concentration of Al 3+ ion is 0.18 mol/L) with different aging time is the function of the basicity and Al 3+ /SO 4 2- molar ratios and has its maximum at r =0.5 and Al 3+ /SO 4 2- =12.

Corrosion behavior of Zr–Nb–Cr cladding alloys

Zr-Nb-Cr alloys were used to evaluate the effects of alloying elements Nb and Cr on corrosion behavior of zirconium alloys. The microstructures of both Zr substrates and oxide films formed on zirconium alloys were characterized. Corrosion tests reveal that the corro- sion resistance of ZrxNb0.1Cr （x = 0.2, 0.5, 0.8, 1.1; wt%） alloys is first improved and then decreased with the increase of the Nb content. The best corrosion resistance can be obtained when the Nb concentration in the Zr matrix is nearly at the equilibrium solution, which is closely responsible for the formation of columnar oxide grains with protective characteristics. The Cr addition degrades the corrosion resistance of the Zrl.lNb alloy, which is ascribed to Zr（Cr,Fe,Nb）2 precipitates with a much larger size than β-Nb.

Effects of Polysaccharides from Pulsatilla Decoction on the Microvascular Endothelial Glycocalyx

Pulsatilla decoction is a famous traditional Chinese herbal formula for clearing heat and treating dysentery of animals or human. To elucidate its mechanism, many active components have been studied, however, the roles of its polysaccharides still remain unclear. This study aimed to explore effects of polysaccharides from Pulsatilla decoction （PPD） on the microvascular endothelial glycocalyx （eGC）. The polysaccharides were extracted from PPD by water extraction and alcohol precipitation method. Mice were administered with PPD for 4 wk, and were then anesthetized with ether inhalation and were ifxed by cardiac perfusion with gradient concentration alcian blue solution. The jejunum was sampled and jejunal mucosa was prepared for ultrathin sections by routine method and was analyzed by transmission electron microscope. The results indicated that the eGC was observed as a strong electron-dense smooth linear margin or nonuniform conglomerates coating cell membranes, and PPD signiifcantly increased its thickness from （21.85±1.87） to （28.71±3.61） nm and improved its integrity. This study suggested that PPD may express their biological activities and protect against pathogenic factor damages by inlfuencing the eGC.

Microstructures and deformation mechanisms of experimentally deformed gabbro

The natural gabbro samples were deformed at temperature ranging from 700 to 1150 ℃ with strain rate steps of 1 ×10^-4, 2.5 ×10^-5, 6.3 ×10^-6 s^-1. The mechanical data show that sample experiences gradual transition from semi-brittle flow to plastic flow, corresponding to a systematically decreasing stress exponent n with the increasing temperature ranging from 16.5 to 4.1 （He et al. Sci China （D） 46（7）：730-742, 2003）. We investigate microstructures and deformation mechanisms of experimentally deformed gabbro under transmission electron microscope in this study. For low temperature of 700 ℃ to 950℃, the deformation is mainly accommodated with dislocation glide and mechanical twinning, corresponding to stress exponent lager than 5, which means semi-brittle deformation. Whereas with higher temperature up to 1000 ℃-1150 ℃, the deformation is accommodated mainly with dislocation glide and climb corresponding to stress exponent of 4.1, which means plastic deformation. Evidence of dislocation climb has been found as dislocation walls in plagioclase. The observed slip system in plagioclase is （001）1/21110] and that in clinopyroxene are （100）[001] and （010）[001]. The （010）[001] slip system in clinopyroxene is newly found in this work. Melt was found at temperature of 950 ℃-1050 ℃. The melt glass distributed both in melt thin film between two grain boundaries and melt tubules of triangular along three grain boundaries at temperature of 950℃-1000℃. The melt triangular interconnected to the melt film at temperature of 1050 ℃-1150℃, where the melt chemical compositiondifferentiated into iron-rich dark dots and silicate-rich matrix.

Microstructure evolution of T91 steel after heavy ion irradiation at 550℃

Fe-Cr ferritic/martensitic(F/M)steels have been proposed as one of the candidate materials for the Generation IV nuclear technologies.In this study,a widely-used ferritic/martensitic steel,T91 steel,was irradiated by 196-MeV Kr^(+)ions at 550℃.To reveal the irradiation mechanism,the microstructure evolution of irradiated T91 steel was studied in details by transmission electron microscope(TEM).With increasing dose,the defects gradually changed from black dots to dislocation loops,and further to form dislocation walls near grain boundaries due to the production of a large number of dislocations.When many dislocation loops of primary a0/2<111>type with high migration interacted with other defects or carbon atoms,it led to the production of dislocation segments and other dislocation loops of a0<100>type.Lots of defects accumulated near grain boundaries in the irradiated area,especially in the high-dose area.The grain boundaries of martensite laths acted as important sinks of irradiation defects in T91.Elevated temperature facilitated the migration of defects,leading to the accumulation of defects near the grain boundaries of martensite laths.

Structural and Piezoelectric Properties of Sr_(0.6)Ba_(0.4)Nb_2O_6 Micro-rods Synthesized by Molten-Salt Method

Sr0.6 Ba0.4 Nb2 O6 micro-rods are prepared by the molten-salt method with K2 SO4,KCl-K2 SO4,and KCl as fluxes.It reveals that the Sr0.6 Ba0.4 Nb2 O6 synthesized with KCl as a flux exhibits a single phase with tetragonal tungsten bronze structure.The measurement of X-ray diffraction indicates that the Sr0.6 Ba0.4 Nb2 O6 micro-rods synthesized at 1 300℃are anisotropic.The morphology of the powers is examined by transmission electron microscope.It reveals that the length-diameter ratio of Sr0.6 Ba0.4 Nb2 O6 micro-rods increases with increasing annealing temperature from 900℃to 1 300℃.At 1 300℃,the rod possesses a large length-diameter ratio of 8∶1.Moreover,the analysis of the piezoelectric properties of single micro-rods using apiezo-response force microscope indicates that the domains of the material are arranged along its radial direction.

Ultrafast electron microscopy in material science

Recent advances in the ultrafast transmission electron microscope （UTEM）, with combined spatial and temporal resolutions, have made it possible to directly visualize the atomic, electronic, and magnetic structural dynamics of materials. In this review, we highlight the recent progress of UTEM techniques and their applications to a variety of material systems. It is emphasized that numerous significant ultrafast dynamic issues in material science can be solved by the integration of the pump-probe approach with the well-developed conventional transmission electron microscopy （TEM） techniques. For instance, UTEM diffraction experiments can be performed to investigate photoinduced atomic-scale dynamics, including the chemical reactions, non-equilibrium phase transition/melting, and lattice phonon coupling. UTEM imaging methods are invaluable for studying, in real space, the elementary processes of structural and morphological changes, as well as magnetic-domain evolution in the Lorentz TEM mode, at a high magnification. UTEM electron energy-loss spectroscopic techniques allow the examination of the ultrafast valence states and electronic structure dynamics, while photoinduced near-field electron microscopy extends the capability of the UTEM to the regime of electromagnetic-field imaging with a high real space resolution.

Influence of InAs deposition thickness on the structural and optical properties of InAs quantum wires

The influence of InAs deposition thickness on the structural and optical properties of InAs/InA1As quantum wires （QWR） superlattices （SLS） was studied. The transmission electron microscopy （TEM） results show that with increasing the InAs deposited thickness, the size uniformity and spatial ordering of InAs QWR SLS was greatly improved, but threading dislocations initiated from InAs nanowires for the sample with 6 monolayers （MLs） InAs deposition. In addition, the zig-zag features along the extending direc- tion and lateral interlink of InAs nanowires were also observed. The InAs nanowires, especially for the first period, were laterally compact. These structural features may result in easy tunneling and coupling of charge carders between InAs nanowires and will hamper their device applications to some extent. Some suggestions are put forward for further improving the uniformity of the stacked InAs QWRs, and for suppressing the formation of the threading dislocations in InAs QWR SLS.

Arc-Discharge Synthesis and Microstructure Characterization of AIN Nanowires

AIN nanowires with a hexagonal structure were synthesized using an improved arc-discharge method and their microstructures were characterized using a high-resolution transmission electron microscope. The synthesized AIN nanowires were of various shapes. Their diameters ranged from 20 to 110 nm and the lengths were up to 20 μm. Most of the AIN nanowires were coated by an amorphous layer of aluminum oxide. Fabrication yield was about several grams. The growth mechanism was considered to be a vapor-liquid-solid process and an AI droplet formed on the top of as-grown AIN nanowire played a role of catalyst.

Structures and magnetic behaviours of TiO_2-Mn-TiO_2 multilayers

The TiO2-Mn-TiO2multilayers are successfully grown on glass and silicon substrates by alternately using radio frequency reactive magnetron sputtering and direct current magnetron sputtering. The structures and the magnetic behaviours of these films are characterised with x-ray diffraction, transmission electron microscope （TEM）, vibrating sample magnetometer, and superconducting quantum interference device （SQUID）. It is shown that the multi-film consists of a mixture of anatase and rutile TiO2 with an embedded Mn nano-film. It is found that there are two turning points from ferromagnetic phase to antiferromagnetic phase. One is at 42 K attributed to interface coupling between ferromagnetic Mn3O4 and antiferromagnetic Mn2O3, and the other is at 97 K owing to the interface coupling between ferromagnetic Mn and antiferromagnetic MnO. The samples are shown to have ferromagnetic behaviours at room temperature from hysteresis in the M-H loops, and their ferromagnetism is found to vary with the thickness of Mn nano-film. Moreover, the Mn nano-film has a critical thickness of about 18.5 nm, which makes the coercivity of the multi-film reach a maximum of about 3.965 × 10^-2 T.