Structures, Phase Transformations, and Dielectric Properties of BiTaO4 Ceramics.

Low (α)- and high-temperature (ß) forms of BiTaO4 have attracted much attention due to their dielectric and photocatalytic properties. In the present work, a third form, the so-called HP-BiTaO4, was synthesized at high temperature and pressure. The phase evolution, phase transformations, and dielectric properties of α- and ß-BiTaO4 and HP-BiTaO4 ceramics are studied in detail. ß-BiTaO4 ceramics densified at 1300 °C with the microwave permittivity εr ≈ 53, the microwave quality factor Qf ≈ 12070 GHz, and the temperature coefficient of resonant frequency τf ≈ -200 ppm/°C. HP-BiTaO4 ceramics were synthesized at 5 GPa and 1300 °C followed by annealing at 600 °C. In contrast with the α phase, HP-BiTaO4 exhibited εr ≈ 195 at 1 kHz to 10 MHz, accompanied by a low dielectric loss of ∼0.004. The relation between structure and dielectric properties is discussed in the context of Shannon's additive rule and bond theory.

[Expression, Purification and Bioinformatics Analysis of ß-hexosaminidase of Dermatophagoides farinae].

The DNA fragment encoding ß-hexosaminidase was synthesized, and cloned into pET-28a vector. The constructed plasmid pMD18-T-ß-hexosaminidase was transformed into E. coli Top 10 and followed by expression of the protein induced by IPTG. SDS-PAGE result showed that the relative molecular mass of the recombinant protein was about M, 55 000. The full length of ß-hexosaminidase gene was 1 410 bp. Bioinformatics analysis revealed that ß-hexosaminidase was composed with 469 amino acid residues with a calculated molecular weight of Mr 55,000, and its secondary structure was composed of strand (14.71%), helix (30.70%), and loop (54.58%). ß-hexosaminidase was a hydrophilic protein without signal peptide, and located in the extracellular space.

CD4+ T cell responses in Balb/c mice with food allergy induced by trinitrobenzene sulfonic acid and ovalbumin.

The rapid increase in atopic diseases is potentially linked to increased hapten exposure, however, the role of haptens in the pathogenesis of food allergy remains unknown. Further studies are required to elucidate the cluster of differentiation 4 positive (CD4+) T cell response to food allergy induced by haptens. Dendritic cells were primed by trinitrobenzene sulfonic acid (TNBS) as a hapten or ovalbumin (OVA) as a model antigen, in a cell culture model. BALB/c mice were sensitized using TNBS and/or OVA. Intestinal Th1/Th2 cell and ovalbumin specific CD4+ T cells proliferation, intestinal cytokines (interleukin­4 and interferon­Î³) in CD4+ T cells were evaluated. TNBS increased the expression of T cell immunoglobulin and mucin domain­4 and tumor necrosis factor ligand superfamily member 4 in dendritic cells. Skewed Th2 cell polarization, extensive expression of interleukin­4, reduced expression of interferon­Î³ and forkhead box protein P3 were elicited following concomitant exposure to TNBS and OVA, with reduced regulatory T cells in the mouse intestinal mucosa, whereas a Th1 response was detected when challenged by TNBS or OVA alone. This data suggests that TNBS, as a hapten, combined with food antigens may lead to a Th2 cell response in the intestinal mucosa.

Effects of recombinant human interleukin-10 on Treg cells, IL-10 and TGF-ß in transplantation of rabbit skin.

The current study aimed to investigate the rejection and survival time of grafted skin, and the changes of Treg cells, interleukin 10 (IL-10) and transforming growth factor-ß (TGF-ß) in peripheral blood following skin transplantation with recombinant human interleukin-10 (rhIL-10) or cyclosporin A (CsA), as well as the role of IL-10 in immunological rejection mechanisms. A total of 36 rabbits were divided into two groups. The skin of a donor rabbit was transplanted onto the back of one receptor rabbit. Receptors were randomly divided into six groups, including rhIL-10 low-dose (5 µg/kg/d), rhIL-10 high-dose (10 µg/kg/d), CsA low-dose (5 mg/kg/d), CsA high-dose (10 mg/kg/d), rhIL-10 (5 µg/kg/d) and CsA (5 mg/kg/d) and negative control normal saline (NS; 1 ml/d). All groups received intramuscular drug injection for ten days, beginning one day prior to skin transplantation surgery. Following transplantation, each rabbit's peripheral blood was collected at different times. The changes of CD4+CD25+ regulatory T cells, IL-10 and TGF-ß were determined by flow cytometry and enzyme-linked immunosorbent assay. When compared with the control group, the rejection and survival times of the experimental groups were longer following skin graft. Compared with the two CsA groups and the control group, the proportion of CD4+CD25+ regulatory T cells of rhIL-10 groups was significantly upregulated on the 4th and 7th days following surgery. However, TGF-ß levels were not significantly different. Data suggested that the concentration of IL-10 was positively correlated with the proportion of CD4+CD25+ regulatory T cells. In addition, IL-10 may delay the rejection time of rabbit skin transplantation and prolong the survival time. Thus, the role of IL-10 in inhibited allograft rejection may be associated with CD4+CD25+ regulatory T cells and IL-10, and may be independent of TGF-ß.