Six new monoterpenoid indole alkaloids, kopsinidines C-E (1-3), 11,12-methylenedioxychanofruticosinic acid (4), 12-methoxychanofruticosinic acid (5), and N(4)-methylkopsininate (7), as well as chanofruticosinic acid (6, as a natural product) and 23 known alkaloids, were obtained from the twigs and leaves of Kopsia officinalis. Their structures were characterized by physical data analysis. All isolated compounds were evaluated for their immunosuppressive activity on human T cell proliferation. Rhazinilam (29) significantly inhibited human T cell proliferation activated by anti-CD3/anti-CD28 antibodies (IC = 1.0 μM) and alloantigen stimulation (IC = 1.1 μM) without obvious cytotoxicity for naïve human T cells and peripheral blood mononuclear cells (0-320 μM). Although it did not affect T cell activation, it induced T cell cycle arrest in the G/M phase and inhibited proinflammatory cytokine production in activated T cells.
With the worldwide spread of the Internet, human activity has become permeated by digital media, which shapes communication and interaction and speeds up the improvement of the experience and diffusion of museum exhibitions. Contemporary museums must understand their audiences, especially with respect to online preferences and surfing involvement experiences. Museums are changing in an effort to attract young netizens to access and use museum resources. Virtual museums are increasingly using digital exhibitions to preserve and apply their collections and establishing online community platforms to interact with young people. This study investigates the underlying mechanism of online community characteristics that enhance audiences’ emotional resonance and involvement. Results from a questionnaire survey (N = 1168) of Taiwan undergraduate students show that perceived relevance and esteem improve their emotional resonance, which can attract new people and maintain existing relationships within their communities. Following flow theory, maintaining community relationship characteristics increases emotional resonance, which, in turn, enhances user involvement, but we found only small significant effects of emotional resonance on involvement. These findings illuminate the mechanism of the attitudinal relationship building and maintenance for online museum communities and advance the practical contributions of online museum community use and effects.
Five conjugated polymers are synthesized,
characterized, and examined
in heterogeneous CO2 photoreduction with H2O.
A promising CO production rate of 10.07 μmol g–1 h–1 is achieved with exclusive formation of CO
in the absence of amine sacrificial agents. This photocatalytic system
is highly stable. No significant degradation in the CO production
rate is observed after 104 h of illumination. The physical and photocatalytic
properties of the polymers are compared, revealing that the lowest
unoccupied molecular-orbital energy could be the most significant
factor in determining the conversion efficiency. On the other hand,
CO2 might be trapped by the tetraalkylammonium bromide
functionality installed in a polymer, hampering CO generation. The
presence of water vapor improves the CO production rate. Density functional
theory (DFT) calculations indicate that water molecules can reduce
the Gibbs free energy difference for CO2 reduction to CO.
This work demonstrates the use of linear conjugated polymers in the
CO2 photoreduction and illuminates the working principles,
paving the way for conversion of solar energy into useful fuels.
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