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Temperature-responsive materials with switching physical properties have been widely researched. Among them, the switchable dielectric perovskite materials show potential applications in the electrical and electronic industries and even the intelligence industries. However, perovskite oxides and hybrid organic-inorganic perovskites, as the most representative switchable dielectric materials, are limited by bad biocompatibility. Herein, we report temperature-dielectric-responsive metal-free perovskite (H 2 dabco)(NH 4 )[BF 4 ] 3 constructed by the strategy of substituting the B site in the general formula ABX 3 (doubly protonated 1,4-diazabicyclo[2.2.2]octane = H 2 dabco). Meanwhile, structurally similar hybrid material (H 2 dabco)Rb[BF 4 ] 3 was designed as a control. They exhibit similar phase-transition characteristics and dielectric response behaviors around 333 K. More interestingly, the ordered-disordered transformation of their organic "spherical" cations (H 2 dabco) was deemed to produce their phase transitions and dielectric response switching. Given its ability to generate a dielectric response, (H 2 dabco)(NH 4 )[BF 4 ] 3 will show the potential application of metal-free perovskite in a future thermal sensing device.

A new one-dimensional chain-like compound of tungstobismuthate, [(W(OH)2)2 (Mn(H2O)3)2(Na3(H2O)14)(BiW9O33)2](Himi)2·16H2O (1) (imi = iminazole), has been synthesized in aqueous solution. The structure of 1 was identified by elemental analysis, IR, thermogravimetry (TG), X-ray photoelectron spectroscopy (XPS), (183)W-NMR, and single crystal X-ray diffraction. To investigate the inhibitory effect of 1 on human gastric adenocarcinoma SGC-7901 cells, cell proliferation and apoptosis initiation were examined by MTT assay (MTT = 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazoliumbromide), flow cytometry, nuclear staining, transmission electron microscopy, single cell gel electrophoresis, DNA fragmentation, and Western blotting. The results showed that 1 inhibited cell proliferation and induced apoptosis in SGC-7901 cells in dose-dependent manner. In addition, 1 also decreased the expression of bcl-2 protein and nuclear factor-κB p65 protein in SGC-7901 cells. And expression of bcl-2 protein exhibits a decreasing trend with increase of concentration of 1. Thus, 1 possessed a potential antitumor activity in SGC-7901 cells. This suggests that polyoxotungstates will provide a promising and novel antitumor agent in prevention and treatment of gastric adenocarcinoma.

Secretory protein I, a protein that is cosecreted with parathormone, has been isolated from bovine parathyroid tissue. The purification procedure was aided by the inclusion in the starting material of fresh tissue that had been incubated with radioactive amino acids to label the newly formed secretory protein I. The isolation of the secretory protein I was then followed by locating the radioactive species. Later, purification was also followed by radioimmunoassay. The procedures included salt fractionation, gel filtration, and two steps of ion-exchange chromatography, yielding a 96-fold purification of secretory protein I. The final product contained two species that were shown to be related by comparison of their tryptic peptides and the release of only a single major residue at each step of the Edman degradation. On the basis of amino acid analysis, secretory protein I contains about 30% acidic amino acid residues, contributing to an isoelectric point of 4.5, and has a minimum molecular weight of about 70 000. It contains 2.6% carbohydrate. A radioimmunoassay was established for secretory protein I. A partial amino acid sequence spanning the first 32 residues of the amino-terminal region was obtained. This portion of the structure appeared to be unrelated to those of the known parathyroid hormonal peptides.