22,924 research outputs found
Zscan4 restores the developmental potency of embryonic stem cells
No full textThe developmental potency of mouse embryonic stem (ES) cells, which is the ability to contribute to a whole embryo, is known to deteriorate during long-term cell culture. Previously, we have shown that ES cells oscillate between Zscan4(-) and Zscan4(+) states, and the transient activation of Zscan4 is required for the maintenance of telomeres and genome stability of ES cells. Here we show that increasing the frequency of Zscan4 activation in mouse ES cells restores and maintains their developmental potency in long-term cell culture. Injection of a single ES cell with such increased potency into a tetraploid blastocyst gives rise to an entire embryo with a higher success rate. These results not only provide a means to rejuvenate ES cells by manipulating Zscan4 expression, but also indicate the active roles of Zscan4 in the long-term maintenance of ES cell potency
Spatially-localized time dependent solutions including turbulence and their interactions in 2D Kolmogorov flow
No full textIn 2D Kolmogorov flow in small aspect ratio domains, spatially-localized solutions such as kink, traveling or time-dependent kink-antikink pars coexist. However, the conservation of the flow rate in the y direction strongly restrict combination of localized solutions and their positioning. We find that by adding a homogeneous flow U y their positioning is controlled and each of localized solutions including a spatially-localized chaos is isolated. Numerical results suggest that these isolated solutions can be elements constructing a whole flow
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
p63 regulates Satb1 to control tissue-specific chromatin remodeling during development of the epidermis
No full textNoDuring development, multipotent progenitor cells establish tissue-specific programs of gene expression. In this paper, we show that p63 transcription factor, a master regulator of epidermal morphogenesis, executes its function in part by directly regulating expression of the genome organizer Satb1 in progenitor cells. p63 binds to a proximal regulatory region of the Satb1 gene, and p63 ablation results in marked reduction in the Satb1 expression levels in the epidermis. Satb1(-/-) mice show impaired epidermal morphology. In Satb1-null epidermis, chromatin architecture of the epidermal differentiation complex locus containing genes associated with epidermal differentiation is altered primarily at its central domain, where Satb1 binding was confirmed by chromatin immunoprecipitation-on-chip analysis. Furthermore, genes within this domain fail to be properly activated upon terminal differentiation. Satb1 expression in p63(+/-) skin explants treated with p63 small interfering ribonucleic acid partially restored the epidermal phenotype of p63-deficient mice. These data provide a novel mechanism by which Satb1, a direct downstream target of p63, contributes in epidermal morphogenesis via establishing tissue-specific chromatin organization and gene expression in epidermal progenitor cells
Fully localised edge states in boundary layers
No full textInvestigation of the laminar-turbulent boundary is performed in a boundary-layer flow. Constant homogeneous suction is applied at the wall in order to prevent the spatial growth of the layer, leading to the parallel Asymptotic Suction Boundary Layer (ASBL). Edge tracking is performed in a large computational domain allowing for full spatial localisation of the structures on the laminar-turbulent separatrix. The obtained dynamics of the state goes through calm and bursting phases. During the latter the structure grows in size, shedding vortices downstream of its core which viscously decay during the calm phases. Comparison with the computation in spatially growing boundary layer is made. The influence of the Reynolds number and the path leading from the edge state to turbulent flow are considered
Turbulent structures in unsteady wall-bounded flow subject to temporal acceleration
No full textDirect numerical simulations (DNS) of a transient turbulent channel flow subject to constant temporal acceleration have been performed with a final Reynolds number of \Retau=800. The response of turbulent structures to the temporal acceleration is investigated. A significant delay in the response of turbulent flow is observed in various turbulent properties. It is found that the response of turbulent flow to temporal acceleration consists of two stages: the destruction of the initial \emph{old} turbulence, followed by the generation of \emph{new} turbulence associated with a higher number. The \emph{new} turbulence is much stronger than the \emph{old} turbulence
Bypass transition in boundary layers as an activated process
No full textWe consider the spatio-temporal aspects of the transition to turbulence in a boundary layer above a flat plate exposed to free-stream turbulence. Combining results from the receptivity to free-stream turbulence with the observation of a double threshold from transition studies in e.g. pipe flow we arrive at a physically motivated prediction for the spatial distribution of nucleation events in boundary layers. We use a cellular automaton to implement a complete model for the spatial and temporal evolution of turbulent patches and show that the model reproduces the statistical features of the boundary layer remarkably well. The success of the modeling shows that bypass transition occurs as a spatiotemporally activated process, where transition is triggered by critical fluctuations imported from the free-stream turbulence
Monotonicity properties of oscillatory solutions of differential equation
No full textsummary:We obtain monotonicity results concerning the oscillatory solutions of the differential equation . The obtained results generalize the results given by the first author in [1] (1976). We also give some results concerning a special case of the above differential equation
DNA fusion gene vaccination mobilizes effective anti-leukemic cytotoxic T lymphocytes from a tolerized repertoire
No full textThe majority of known human tumor-associated antigens derive from non-mutated self proteins. T cell tolerance, essential to prevent autoimmunity, must therefore be cautiously circumvented to generate cytotoxic T cell responses against these targets. Our strategy uses DNA fusion vaccines to activate high levels of peptide-specific CTL. Key foreign sequences from tetanus toxin activate tolerance-breaking CD4+ T cell help. Candidate MHC class Ibinding tumor peptide sequences are fused to the C terminus for optimal processing and presentation. To model performance against a leukemia-associated antigen in a tolerized setting, we constructed a fusion vaccine encoding an immunodominant CTL epitopederived from Friend murine leukemia virus gag protein (FMuLVgag) and vaccinated tolerant FMuLVgag-transgenic (gag-Tg) mice. Vaccination with the construct induced epitopespecificIFN-c-producing CD8+ T cells in normal and gag-Tg mice. The frequency and avidity of activated cells were reduced in gag-Tg mice, and no autoimmune injury resulted. However, these CD8+ T cells did exhibit gag-specific cytotoxicity in vitro and in vivo. Also, epitope-specific CTL killed FBL-3 leukemia cells expressing endogenous FMuLVgag antigen and protected against leukemia challenge in vivo. These results demonstrate a simple strategy to engage anti-microbial T cell help to activate epitope-specific polyclonal CD8+ T cell responses from a residual tolerized repertoire
Semana Santa y su simbología. 5 Segunda época Año 3 (2019) enero-junio. Rutas de Campo. Trabajo de Campo: Iztapalapa: memoria y cultura
No full textLos dos grandes momentos en torno a los cuales gira la cosmovisión católica, el nacimiento de Jesús y su muerte, han dado lugar, el primero, a la celebración de la Navidad, y el segundo, a la conmemoración de Semana Santa. En este texto nos ocuparemos de los años finales de la vida de Jesús, pues es precisamente Semana Santa la celebración litúrgica con que se recuerda su Pasión y su muerte. Recordemos que, en este contexto, el término “pasión” hace referencia al sufrimiento y a la serie de tormentos a que fue sometido Jesús poco antes de su muerte en la cruz, que todos conocemos.Altamirano, Ignacio Manuel (1974). Paisajes y leyendas. Tradiciones y costumbres de México. México: Porrúa.Calendario de fiestas tradicionales (1988). México: Dirección General de Culturas Populares-SEP.Calendario Litúrgico Pastoral 1991 (1990). México: Obra Nacional de la Buena Prensa.Campos, Rubén M. (1929). El folklore literario en México. Investigación de la producción literaria popular. México: Talleres Gráficos de la Nación._____ (1958). “Semana Santa”. En Fiesta. México: Talleres de la Secretaría de Hacienda.Castelló Iturbide, María Teresa (1958). “El altar del Viernes de Dolores”. En Fiesta. México: Talleres de la Secretaría de Hacienda.Catalán Blanco, Juan Carlos (s.f.). “Las fiestas de carnestolendas y la celebración de la Semana Santa en la época colonial” [inédito]. s.l.: Dirección General de Culturas Populares de Guerrero-SEP.Cid, Carlos, y Manuel Riu (1965). Historia de las religiones. Barcelona: Sopena._____ (1987). Compendio de historia sagrada y de la historia de la Iglesia. México: Progreso.Crumrine N., Roos (1979). “Cuaresma”. En Gran Enciclopedia Rialp. Madrid: Rialp.Estrada, Genaro (1945). Visionario de la Nueva España. México: Patria.Estrada, Humberto (1985). “La cuaresma” [inédito]. s.l.: Dirección General de Culturas Populares-SEP.Foster, George M. (1962). Cultura y conquista. Xalapa: Universidad Veracruzana.García Cubas, Antonio (1945). El libro de mis recuerdos. México: Patria.González Obregón, Luis (1936). Croniquillas de la Nueva España. México: Botas.____(1941). Las calles de México. México: Botas.Horcasitas, Fernando (1974). El teatro náhuatl: época novohispana y moderna. México: IIH-UNAM.Iglesias y Cabrera, Sonia C. (1996). Tradiciones de Cuaresma y Semana Santa. México: Museo Nacional de Culturas Populares-Dirección General de Culturas Populares._____ (2001). La semana Santa en México. Con la muerte en la cruz. México: Dirección General de Culturas Populares.Lercaro, Giacomo (1960). ¿Cuál es el vocabulario de la liturgia católica? México: Novaro.Macgowan, Kenneth, y William Melnitz (1964). Las edades de oro del teatro. México: FCE.Mendieta, Gerónimo de (1945). Historia eclesiástica indiana. México: Salvador Sánchez.Mendoza, Vicente T., y Adalberto Fuentes Cruz (1945). “Drama de la Pasión intitulado: el drama del Gólgota, que se representa en la delegación de Milpa Alta, D.F.”. Anuario de la Sociedad Folklórica de México, 6.Moreno Toscano, Alejandra (1981). “La conquista espiritual”. En Historia general de México. México: El Colegio de México.Olavarría Ferrari, Enrique de (1953). “Pasión de Cristo”. En Enciclopedia de la religión católica [t. V]. Barcelona: Dalma y Jovier._____ (1961). Reseña del teatro en México. México: Porrúa.Pike E., Royston (1986). Diccionario de religiones. México: FCE.Prieto, Guillermo (1969). Memorias de mis tiempos. México: Patria.Rodríguez, Mariángela (1991). Hacia la estrella con la Pasión y la ciudad a cuestas. Semana Santa en Iztapalapa. México: Ediciones de la Casa Chata-CIESAS.Sociedad Bíblica Británica y Extranjera de Londres (1929). La Santa Biblia. Londres: SBBEL.Vetancurt, Agustín de (1941). Teatro mexicano: descripción breve de los sucesos exemplares de la Nueva España en el mundo occidental de las Indias. Madrid: J. Porrúa.Verti, Sebastián (1991). Tradiciones mexicanas. México: Diana.Weckmann, Luis (1984). La herencia medieval de México. México: FCE
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