4,729 research outputs found

    Effect of mesenchymal stem cell transplantation on behavior and structural changes in myelin in experimental rat autoimmune encephalomyelitis

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    Purpose: To investigate the effect of bone marrow mesenchymal stem cell (BM-MSC) transplantation on behavior and structural changes in myelin of experimental autoimmune encephalomyelitis (EAE) in rats.Methods: Wistar rats were randomly assigned to normal control, EAE, placebo injection treatment, and MSCs treatment. EAE, placebo injection treatment and MSCs treatment groups were further divided into six groups, i.e., 1-day, 3-day, 7-day, 14-day, 21-day, and 28-day post-onset. Changes in the diseasestatus of the rats and structural changes in myelin at different time points were assessed with silver staining.Results: Behavioral changes peaked between 13 to 17 days post-immunization (71.90 % incidence), while disease symptoms peaked between 3 and 5 days after onset, were sustained for about 7 days, and then eased gradually thereafter. The highest therapeutic scores and the entire course of the disease in EAE and placebo treatment groups were not significantly different (p > 0.05). However, in MSC treatment group, these parameters were significantly lower than in the above two groups (p < 0.05). In EAE and placebo treatment groups, myelin sheath lesions were obvious from day 3 to 7 but on day 14, the number of myelin sheath fragments decreased significantly. Recovery at different time points was also better than those in EAE and placebo treatment groups.Conclusion: MSC transplantation shortens the course of EAE, and also reduces its severity. Thus, it has some prospects for use in the management of EAE.Keywords: Bone marrow mesenchymal stem cells, Autoimmune encephalomyelitis, Transplantation, Myeli

    Raman spectroscopy and imaging of graphene

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    Graphene has many unique properties that make it an ideal material for fundamental studies as well as for potential applications. Here we review the recent results on the Raman spectroscopy and imaging of graphene. Raman spectroscopy and imaging can be used as a quick and unambiguous method to determine the number of graphene layers. Following, the strong Raman signal of single layer graphene compared to graphite is explained by an interference enhancement model. We have also studied the effect of substrates, the top layer deposition, the annealing process, as well as folding (stacking order) on the physical and electronic properties of graphene. Finally, Raman spectroscopy of epitaxial graphene grown on SiC substrate is presented and strong compressive strain on epitaxial graphene is observed. The results presented here are closely related to the application of graphene on nano-electronic device and help on the better understanding of physical and electronic properties of graphene.Comment: 32 pages, 14 figure

    A Bridge Between Two Worlds: a Cultural Interpretation of Dragonwings

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    Living in the dual worlds of his life as a Chinese American and in places such as Chinatown, Laurence Yep felt that he was culturally alienated and that he did not have a culture of his own. With the driving wish to find out about Chinese culture―his culture, he finished his best known novel Dragonwings after six years of research on Chinese culture. Based on the true story of Fung Joe Guey, a Chinese American who built and flew an airplane in the Oakland hills in 1909, Dragonwings tells the story of Moon Shadow, who comes to San Francisco to join his unknown father, Windrider, who cherishes the dream of flying. To pursue the dream, Moon Shadow and his father have to move out of Chinatown. After enduring a sea of misunderstanding, cruelty and poverty, Windrider finally realizes his flying dream with the support and aid of his beloved son and his fellowmen, as well as his American friends. Trying to show the process from misinterpretation and misunderstanding to mutual understanding and the possibilities of cultural exchange and cultural fusion between two different cultures, we will discuss how the Chinese culture is rediscovered by a Chinese American and how cultural misunderstanding leads to an unbalanced world and how tolerance and understanding restore the world into a harmonious one. This paper attempts to demonstrate, through the analysis of Dragonwings, the author’s exploration of Chinese culture, cultural exchange and human nature transcending cultural differences. Key words: Dragonwings, Laurence Yep, cultural exchange Abstrait: En vivant dans le monde dual de sa vie comme Américain chinois et aux endroits comme la Cité chinoise, Laurence Yep trouve qu’il était aliéné culturellement et qu’il n’avait pas de culture de sa ville. Avec l’espoir violent à découvrir la culture chinoise----sa culture, il a achevé son roman bien connu Dragon-ailes après une recherche de six années sur la culture chinoise. Basé sur l’histoire vraie de Fung Joe Guey , un Américain Chinois qui a fabriqué et manié un avion dans les Montagnes Oakland en 1909, Dragon-ailes raconte le conte de Ombre de lune, qui vient à San Francisco pour rejoindre son père inconnu , Windrider, qui a le rêve de voler .Poursuivant le rêve, Ombre Lunaire et son père sont obligés de bouger de la Cité chinoise. Après avoir enduré une mer d’incompréhension , de cruauté et de pauvreté, Windrider a finalement réalizé son rêve de voler avec l’aide de son fils et ses compagnons, ainsi que ses amis américains. Essayant de montrer le processus de malinterprétation et de incompréhension à compréhension mutuelle et les possibilités d’échange et de fusion culturels entre deux cultures différentes, nous discuterons comment la culture chinoise est redécouverte par un Américian chinois et comment l’incompréhension culturelle conduit à un monde inégal et comment la tolérance et la compréhension reconstruisent le monde à celui d’harmonique. Ce papier tente de démontrer , à travers l’analyse de Dragon-ailes , l’exploration de l’auteur de la culture chinoise , de l’échange culturel et des différences transcendantes naturelles de la nature humaine. Mots clefs: Dragon-ailes, Laurence Yep, échange culture

    Single deep ultraviolet light emission from boron nitride nanotube film

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    Light in deep ultraviolet DUV region has a wide range of applications and the demand for finding DUV light emitting materials at nanoscale is increasingly urgent as they are vital for building miniaturized optic and optoelectronic devices. We discover that boron nitride nanotubes BNNTs with a well-crystallized cylindrical multiwall structure and diameters smaller than 10 nm can have single DUV emission at 225 nm 5.51 eV. The measured BNNTs are grown on substrate in the form of a thin film. This study suggests that BNNTs may work as nanosized DUV light sources for various applications. © 20

    Tetra­aqua­tetra­kis­(4,4′-bipyridine dioxide-κO)terbium(III) octa­cyanidotungstate(V)

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    In the title compound, [Tb(C10H8N2O2)4(H2O)4][W(CN)8], both metal atoms are eight-coordinated. The TbIII ion displays a dodeca­hedral geometry, while the Wv ion exhibits a distorted square-anti­prismatic geometry. The Tb atoms are located on a special position of site symmetry -4, whereas the W atoms are located on a twofold rotation axis. The cations are linked by O—H⋯O hydrogen bonds. The title compound is isotypic with the corresponding and previously described Mo compound [Qian & Yuan (2011 ▶). Acta Cryst. E67, m845]

    Tianditu: China's first official online mapping service

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    Tianditu is China’s first state-sponsored web mapping service. Beijing considers Tianditu part and parcel of its burgeoning endeavor to build a ‘digital China’. The Chinese state created Tianditu to regain some of the ground lost when its monopoly on geographic information was effectively broken. This effort goes hand in hand with Beijing’s intention to compete with and shrink the space occupied by Google mapping services (Google Maps, Google Earth, etc.). Although Tianditu does bestow a certain degree of power on civilian users to interact with and explore geographic data, for political and social reasons the Chinese state tightly controls Tianditu. It is a tool that the regime uses to maintain political power and push ideologies it supports. This type of top-down reinforcement of static geographic knowledge is a far cry from the concept of civilian empowerment as understood in liberal democracies

    Ray solvable linear systems and ray S2NS matrices

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    AbstractRay solvable linear systems and ray S2NS matrices are complex generalizations of the sign solvable linear systems and S2NS matrices. We use the determinantal ray unique matrices (instead of ray nonsingular matrices) as a generalization of SNS matrices, to generalize some fundamental results of S2NS matrices from the real case to complex case, such as the graph theoretical characterization, the inverse ray patterns and the upper bound of the number of nonzero entries of S2NS matrices. The well known characterization of the sign solvable linear systems (in terms of the L-matrices and S∗ matrices) is also generalized to ray solvable linear systems, and the relationships between the ray S∗-matrices and real S∗-matrices are investigated. Some examples are also given to illustrate that some results, such as the characterization of the sign inconsistent linear systems, do not carry over to the complex case
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