Programming a Metal-Organic Framework toward Excellent Hypergolicity.

Exploring novel hypergolic fuels for modern space propulsion is highly desired. However, the analysis and understanding of the structure and hypergolic performance at the molecular level are still insufficient. To understand the factors that dictate hypergolicity, we conducted a comparative study on a series of metal-organic frameworks (MOFs) characterized by the same topology but with varied ligand structures. The ignition delay (ID) time trend was found to be imidazole < triazole < tetrazole, and the rapid ID time was 8 ms. By combining experimental studies and density functional theory (DFT) calculations, we found that propargyl and cyanoborohydride groups that functioned as dual hypergolic triggers contributed to the hypergolicity, and a distinct electronic structure was detrimental to ID time. The structure-performance relationships presented herein can potentially provide some fundamental insights into the field of developing high-performance hypergolic fuels.

[Vibrational spectra of scheelite and its color genesis].

In order to study the spectral characteristics and color-genetic mechanism of the scheelite with orange color found in scheelite-tin-beryl (W-Sn-Be) deposits in Xuebaoding, four groups of scheelite were investigated by means of EMPA, IR, LRM and XRD. The scheelite samples were tested by XRD and IR in order to reveal if there are other minerals intermingled with scheelite. Meanwhile, the structure, the structure water and the crystal water were studied through infrared spectra. The absorption bands and peaks of infrared and Raman spectra were assigned. Finally, it seems that there is no distinct color difference between scheelite from Xue baoding and those from other places. So, it is conceived that the color causing may correlate with the minor crystal structure, trace element or REE in the crystal.

Curcumin improves synaptic plasticity impairment induced by HIV-1gp120 V3 loop.

Curcumin has been shown to significantly improve spatial memory impairment induced by HIV-1 gp120 V3 in rats, but the electrophysiological mechanism remains unknown. Using extracellular microelectrode recording techniques, this study confirmed that the gp120 V3 loop could suppress long-term potentiation in the rat hippocampal CA1 region and synaptic plasticity, and that curcumin could antagonize these inhibitory effects. Using a Fura-2/AM calcium ion probe, we found that curcumin resisted the effects of the gp120 V3 loop on hippocampal synaptosomes and decreased Ca(2+) concentration in synaptosomes. This effect of curcumin was identical to nimodipine, suggesting that curcumin improved the inhibitory effects of gp120 on synaptic plasticity, ameliorated damage caused to the central nervous system, and might be a potential neuroprotective drug.

[Protective effect and mechanism of curcumin on ActD/TNF-α-induced synergistically apoptosis in PC12 cells].

AIM: To investigate the protective effect and mechanism of curcumin against ActD/TNF-α-induced synergistically apoptosis in PC12 cells. METHODS: MTT assay was used to evaluate the optimal concentration of drugs; Hoechst 33258 fluorescent staining to observe apoptosis of PC12 cells, JC-1 was used to detect the mitochondrial membrane potential (MMP), real-time PCR was used to detect the expression of two apoptotic genes: Bcl-1 and Bax. RESULTS: ActD/TNF-α can synergistically reduce viability of PC12 cells(P<0.05), increase the number of cells with pyknosis and karyorrhexis, increase apoptotic rate of cells (P<0.05), decrease MMP in cells, and downregulate expression of Bcl-2(P<0.05). After treating with curcumin(5 µmol/L), survival of PC12 cells was increased(P<0.05), the number of cells with pyknosis and karyorrhexis was reduced, MMP and expression of Bcl-2 were increased(P<0.05). CONCLUSION: Curcumin can resist the ActD/TNF-α-induced synergistically apoptosis in PC12 cells, the mechanisms of which may be related to an increase in MMP and Bcl-2 expression.

The OsEBP-89 gene of rice encodes a putative EREBP transcription factor and is temporally expressed in developing endosperm and intercalary meristem.

The AP2/EREBP transcription factors play important roles in plant development and in the responses of plants to biotic and abiotic stresses. All members of the EREBP subfamily described to date are from dicotyledonous plants. In this paper, we describe the cloning and characterization of a rice gene, OsEBP-89, encoding a protein 326 amino acids long with a typical EREBP domain; this is the first report of an EREBP transcription factor in a monocotyledonous plant. Except for the EREBP domain, the OsEBP-89 protein does not have substantial sequence similarities to other members of the subfamily. The DNA-binding activity of the EREBP domain was confirmed by electrophoretic mobility-shift assays. An activation domain rich in acidic amino acids was identified by using a yeast one-hybrid system. Two putative nuclear-localization signals were also identified. The results of northern blot hybridization experiments showed that the transcript of the OsEBP-89 gene accumulates primarily in immature seeds, roots, and leaves (low levels). More detailed information about the pattern of OsEBP-89 gene expression was obtained by histochemical studies of transgenic rice plants carrying an OsEBP-89 5'/GUS reporter gene. The reporter gene was expressed in the endosperm starting at 7 days after pollination and in the intercalary meristem of plants. Expression of OsEBP-89 was induced in roots of rice seedlings by treatment with ACC, NaCl, or 2,4-D. Two cis-acting elements, an endosperm motif and a primary PERE, are present upstream of the OsEBP-89 coding region and may be involved in regulating its expression. Collectively, these results suggest that the OsEBP-89 gene is a new member of the EREBP subfamily and may be involved in ethylene-dependent seed maturation and shoot development of rice.