1,026 research outputs found
T. Sugimura, The Encounter of Persia With China. Research into Cultural Contacts Based on Fifteen Century Persian Pictorial Materials
No full textPirazzoli-T'serstevens Michèle. T. Sugimura, The Encounter of Persia With China. Research into Cultural Contacts Based on Fifteen Century Persian Pictorial Materials. In: L'Homme, 1987, tome 27 n°101. Du bon usage des dieux en Chine. pp. 148-150
Induction of poly(ADP-ribose) polymerase gene expression in lectin-stimulated human T lymphocytes is dependent on protein synthesis
No full textThe poly(ADP-ribose) polymerase mRNA level in quiescent T lymphocytes was low, but was significantly higher than that in B lymphocytes or monocytes. When T lymphocytes were stimulated with phytohemagglutinin, a prompt increase in the mRNA level was observed from 4 hours after stimulation. The level of poly(ADP-ribose) polymerase mRNA reached a maximum in the late G1 phase about 1-2 days after lectin stimulation, and then decreased gradually returning to the basal level 10 days after lectin stimulation. Cycloheximide abrogated increase in poly(ADP-ribose) polymerase gene expression suggesting that a newly synthesized protein(s) was involved in poly(ADP-ribose) polymerase gene induction in lectin-stimulated T lymphocytes
The application of vascular immune organoids from human pluripotent stem cells in cancer immunotherapy and SARS-CoV-2 modeling
No full textOrganoid technology has advanced our understanding of development and disease models. Organoids derived from either human pluripotent stem cells or tissue stem cells offer us the amenable platform to genetically intervene in human organ development. The advance of genetic engineering and stem cell technology pushed the limit of what organoids can do. However, the current lack of both vasculatures and immune cells hinders the understanding of how vasculatures and immune cells regulate organ development as well as their role in pathologic conditions such as cancer and infection. We have previously established a unique organoid system from human pluripotent stem cells (Ohta et al., 2019; Sugimura et al., 2020, 2017). Followed by mesodermal patterning and hemato-endothelial specification with define factors, we achieved vascular immune organoids (VIOs). We identified the highly vascularized structure of VIOs. The repertoire of cells encompasses innate immune cells such as macrophages, neutrophils, erythroblasts, and NK cells, which demonstrated functional maturity. In this talk, we will share our recent efforts in i) engineering functional immune cells for cancer immunotherapy, ii) modeling vasculitis in SARS-CoV-2 infection. We propose that VIOs could further enhance the organoid technology in both cancer immunotherapy and SARS-CoV-2 modeling. References Ohta, R., Sugimura, R., Niwa, A., Saito, M.K., 2019. Hemogenic Endothelium Differentiation from Human Pluripotent Stem Cells in A Feeder- and Xeno-free Defined Condition. J. Vis. Exp. JoVE. https://doi.org/10.3791/59823 Sugimura, R., Jha, D.K., Han, A., Soria-Valles, C., da Rocha, E.L., Lu, Y.-F., Goettel, J.A., Serrao, E., Rowe, R.G., Malleshaiah, M., Wong, I., Sousa, P., Zhu, T.N., Ditadi, A., Keller, G., Engelman, A.N., Snapper, S.B., Doulatov, S., Daley, G.Q., 2017. Haematopoietic stem and progenitor cells from human pluripotent stem cells. Nature 545, 432–438. https://doi.org/10.1038/nature22370 Sugimura, R., Ohta, R., Mori, C., Li, A., Mano, T., Sano, E., Kosugi, K., Nakahata, T., Niwa, A., Saito, M.K., Torisawa, Y.-S., 2020. Biomimetic aorta-gonad-Mesonephros-on-a-Chip to study human developmental hematopoiesis. Biomed. Microdevices 22, 34. https://doi.org/10.1007/s10544-020-00488-
The application of vascular immune organoids from human pluripotent stem cells in cancer immunotherapy and SARS-CoV-2 modeling
No full textOrganoid technology has advanced our understanding of development and disease models. Organoids derived from either human pluripotent stem cells or tissue stem cells offer us the amenable platform to genetically intervene in human organ development. The advance of genetic engineering and stem cell technology pushed the limit of what organoids can do. However, the current lack of both vasculatures and immune cells hinders the understanding of how vasculatures and immune cells regulate organ development as well as their role in pathologic conditions such as cancer and infection. We have previously established a unique organoid system from human pluripotent stem cells (Ohta et al., 2019; Sugimura et al., 2020, 2017). Followed by mesodermal patterning and hemato-endothelial specification with define factors, we achieved vascular immune organoids (VIOs). We identified the highly vascularized structure of VIOs. The repertoire of cells encompasses innate immune cells such as macrophages, neutrophils, erythroblasts, and NK cells, which demonstrated functional maturity. In this talk, we will share our recent efforts in i) engineering functional immune cells for cancer immunotherapy, ii) modeling vasculitis in SARS-CoV-2 infection. We propose that VIOs could further enhance the organoid technology in both cancer immunotherapy and SARS-CoV-2 modeling. References Ohta, R., Sugimura, R., Niwa, A., Saito, M.K., 2019. Hemogenic Endothelium Differentiation from Human Pluripotent Stem Cells in A Feeder- and Xeno-free Defined Condition. J. Vis. Exp. JoVE. https://doi.org/10.3791/59823 Sugimura, R., Jha, D.K., Han, A., Soria-Valles, C., da Rocha, E.L., Lu, Y.-F., Goettel, J.A., Serrao, E., Rowe, R.G., Malleshaiah, M., Wong, I., Sousa, P., Zhu, T.N., Ditadi, A., Keller, G., Engelman, A.N., Snapper, S.B., Doulatov, S., Daley, G.Q., 2017. Haematopoietic stem and progenitor cells from human pluripotent stem cells. Nature 545, 432–438. https://doi.org/10.1038/nature22370 Sugimura, R., Ohta, R., Mori, C., Li, A., Mano, T., Sano, E., Kosugi, K., Nakahata, T., Niwa, A., Saito, M.K., Torisawa, Y.-S., 2020. Biomimetic aorta-gonad-Mesonephros-on-a-Chip to study human developmental hematopoiesis. Biomed. Microdevices 22, 34. https://doi.org/10.1007/s10544-020-00488-
Director reorientation processes in a monodomain thin nematic liquid crystal film: a deuterium NMR spectroscopy study
No full textDeuterium nuclear magnetic resonance (NMR) spectroscopy has been used to investigate the director dynamics in the nematic liquid crystal, 4-pentyl-4'-cyanobiphenyl (5CB), confined between two glass plates and subject to magnetic and electric fields. The nematic cell was held in the NMR probe head so that the electric field, whose direction is normal to the substrate surface, makes an angle of about 45° with the magnetic field. This experimental geometry avoids the degeneracy in the field-induced alignment pathway for the director found for larger angles. A series of deuterium NMR spectra, obtained using a quadrupolar echo sequence, was acquired as a function of time. When the electric field, whose intensity is controlled so that the director makes an angle with the magnetic field is applied to the nematic film, the director moves from being parallel to the magnetic field to being at an angle with respect to the magnetic field because ?(?)over tilde and ?(?)over tilde are both positive for 5CB. After the electric field is switched off, the director relaxes back to being parallel to the magnetic field. Deuterium NMR spectra were recorded during the turn-on and the turn-off alignment processes as a function of time. The realignment pathway of the director was monitored by measuring ?(?)over tilde, the deuterium quadrupolar splitting. We have studied the time dependence of the director orientation for the turn-on and turn-off processes at different temperatures in the nematic phase. The temperature independence of ?(?)over tilde/?(?)over tilde is also discussed on the basis of experiment and theory. The diamagnetic anisotropy and the rotational viscosity coefficient were also determined as a function of temperature. The deuterium NMR spectra corresponding to the field-induced director dynamics were predicted by an analysis based on hydrodynamic theory
Field-induced director dynamics in a nematic liquid crystal: a molecular site dependence?
No full textStudies of the field-induced alignment of the nematic director for low molar mass materials using vibrational spectroscopy have revealed some fascinatingly unexpected results. Several studies have found that the relaxation time for the director alignment is dependent on the group in the molecule used to monitor the director orientation. Seemingly this undermines the basic concept of the Leslie-Ericksen hydrodynamic theory of nematics. Here we report complementary studies using deuterium NMR spectroscopy of perdeuteriated 4-pentyl-4'-cyanobiphenyl where the director is aligned by a magnetic or an electric field. This particular technique was chosen because the spectral peaks associated with each rigid group in the molecule are clearly resolved and of comparable intensity. We have investigated the director alignment using different temperatures, electric field strengths and angles between the magnetic and electric fields, each of which influences the director relaxation time. For all of the experiments we find that the relaxation times are independent of the group used to determine the director orientation during the alignment process
Electric field-induced alignment of the directors in the smectic A phase of 4-octyl-4'-cyanobiphenyl. A deuterium NMR study
No full textDeuterium nuclear magnetic resonance (NMR) spectroscopy has been used to investigate the electric field-induced alignment of the director of the smectic A phase of the liquid crystal, 4-?,?-d(2)-octyl-4'-cyanobiphenyl (8CB-d(2)), at 303.3K. The electric field is arranged to be orthogonal to the magnetic field. The alignment process has been investigated at different electric field strengths and the rate of director alignment was monitored by recording the deuterium NMR spectra as a function of time after the electric field was switched on. The results reveal a complex pattern of electric field-induced director alignment. At high electric field strengths a rapid process is observed in which the director switches from an orientation parallel to the magnetic field to one in which it is parallel to the electric field. An induction period is also observed in which no apparent change in director orientation occurs. This induction period becomes longer (hours in magnitude) as the electric field strength is lowered. Other, intermediate, director orientations are observed as the electric field strength is lowered further. The role of defects is invoked in trying to interpret some of the observed processes underlying the mechanism of the director alignment in the smectic A phase
The alignment of the smectic a phase of 4-octyl-4'-cyanobiphenyl induced by an electric field. A time-resolved deuterium NMR study
No full textStudies of the field-induced alignment of the SmA phase using deuterium NMR spectroscopy have revealed a complex pattern of behaviour when the director is initially orthogonal to the aligning field. Here we report the electric field-induced alignment of the SmA director using time-resolved deuterium NMR when the aligning electric field E is at an angle with the magnetic field B of the spectrometer which is considerably smaller than 90degrees; here the director is initially aligned parallel to the magnetic field. The dynamics of the electric field-induced alignment of the director for the smectic phase of 4-alpha,alpha-d(2)-octyl-4'-cyanobiphenyl (8CB-d(2)) was investigated at two angles between B and E of roughly 45degrees and 54.5degrees the so-called magic angle, at different electric field strengths and also at two temperatures, 305.1 K and 302.6 K The dynamics of the SmA director alignment of 8CB-d(2) was monitored by measuring the deuterium NMR spectrum as a function of time. The results for the 45degrees and 54.5degrees geometries revealed, in contrast to the complex dynamics of alignment of the SmA director observed for the 90degrees geometry, a much simpler pattern of relaxation. Here the director appeared to be aligned almost as a monodomain. In general, for either of the two geometries employed here, the ultimate angle of alignment the director achieves relative to E depends on the electric field strength. Lowering the temperature by just 2.5degreesC from 305.1 K to 302.6 K has a dramatic effect on the rate of director relaxation presumably because of the large increase in the combined rotational viscosity and the elastic energy effects of the SmA phase with decreasing temperature. Furthermore for the 45 geometry at 302.6 K, the SmA sample separates on relaxation ultimately into two domains with different alignment angles
Field-induced director dynamics in the nematic phase of 4-octyl-4'-cyanobiphenyl. A deuterium NMR investigation
No full textThe response times of liquid crystal display devices are determined by a range of factors but the most important of these is usually the rotational viscosity coefficient, gamma(1). In order to understand the relationship between molecular structure and viscosity it is of considerable interest to measure this viscosity coefficient for a variety of nematogens. Here we report the determination of gamma(1) for 4-octyl-4'-cyanobiphenyl-d(2) at two temperatures using deuterium NMR spectroscopy. In these experiments the time taken for the alignment of the director can be changed by a field, either magnetic or electric. To do this the liquid crystal film was enclosed in a cell which allows the application of an electric field within the NMR spectrometer. The rate of director relaxation was followed by recording the deuterium NMR spectrum as a function of time during the process of turning the electric field on or off. We have carried out the experiments for a geometry in which the director orientation with respect to the magnetic field of the spectrometer does not exceed 45degrees. The alignment of the director throughout the relaxation process was observed to be uniform. The director relaxation was found to follow closely the predictions of the torque-balance equation given by the Leslie-Eriksen theory. The relaxation times for the turn-on and turn-off processes were determined from this equation and found to be of the order of 1-2 ms. A knowledge of the anisotropic electric and magnetic susceptibilities then allows the determination of the rotational viscosity coefficient
The Interplay Between Personal Identity and Social Identity Among Vocational High School Students: A Three-Wave Longitudinal Study
No full textAlthough identity research has predominantly focused on college-bound adolescents, it has largely neglected vocational high school students who enter the job market immediately after graduation. Furthermore, most studies have concentrated on personal identity and have overlooked the concurrent development of social identity. This study examined the relationship between adolescents’ personal and social identities over three years of vocational high school. The participants were 4,264 vocational high school students in Japan (Time 1: 46.44% girls; Mage = 15.78). Using a random intercept cross-lagged panel model, the results indicated that within-person increases in social identity predicted increases in personal identity one year later. These findings highlight the importance of social identity as a valuable resource for personal identity development among vocational high school students, a group underrepresented in identity research
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