Preparation of Novel Mesoporous Silica Using a Self-Assembled Graphene Oxide Template.

Novel mesoporous silicas rolled with silica sheets with 2D regular spacing were prepared using a self-assembled graphene oxide (GO) template formed by mixing GO with Pluronic123 (P123). Self-assembled GO templated mesoporous silicas (SGT-PMS) showed well-developed X-ray diffraction peaks with d-spacings of 9.8-10.8 nm depending on the amount of GO, indicating mesoporous structures. The specific surface areas increased from 603.8 to 861.2 m2g-1 on adding GO. The pore size distribution was in the range 5.1-5.8 nm and pore volume in the range 0.80-0.99 m3g-1. The SEM images of SGT-PMS showed irregular elliptical particles with various sizes. TEM images showed that the cross section of SGT-PMS particles comprises a roll of silica sheets with 2D regular spacing. The pore walls of SGT-PMS are firmer and thicker than those for PMS without GO as indicated by the corresponding intensities of Q3 and Q4 signals. These results were explained well by the self-assembled GO templating mechanism.

Preparation of Mesoporous Silica by Nonionic Surfactant Micelle-Templated Gelation of Na2SiO3 and H2SiF6 and Application as a Catalyst Carrier for the Partial Oxidation of CH4.

Mesoporous silica (MSPN12) was prepared by nonionic surfactant micelle-templated gelation of sodium silicate (Na2SiO3) and fluorosilicic acid (H2SiF6) in aqueous solution, characterized by a range of instrumental techniques, and tested as a support for Ni and Rh catalysts in the partial oxidation of methane (POM). Calcined and sintered MSPN12 exhibited well-defined d00l-spacings (3.5-4.39 nm), narrow pore distributions (2.4-3.1 nm), and large specific surface areas (552-1,246 m2 g-1), and was found to be highly thermally stable. Microscopic imaging revealed that MSPN12 comprised spherical particles with a uniform diameter of ~0.7 µm, with each particle featuring firm and regular honeycomb-type pores. MSPN12-loaded Ni and Rh maintained stable POM activity at 700 °C during almost 100 h on stream, which were comparable to those for the commercial Rh(5)/Al2O3 catalyst in terms of methane conversion and H2 formation selectivity. Thus, the combination of structural stability and favorable physicochemical properties resulted in good POM performance.

Preparation of cubic SiC from δ-Na2Si2O5/carbon nanocomposite using cobalt catalyst.

Silicon carbide (SiC) was prepared by carbothermal reduction of a crystalline-layered sodium silicate (δ-Na2Si2O5)/carbon nanocomposite (LCN), which contained a stacked carbon film embedded with cobalt between the silicate layers. Subsequent sintering of this mixture for 3 h at 1000-1350°C resulted in the formation of graphitic carbon and SiC. Meanwhile, sintering without a cobalt catalyst resulted in the formation of graphitic carbon, regardless of the temperature. The use of a cobalt catalyst allowed the formation of a pure SiC phase at 1350°C. The formed SiC had an irregular worm-like morphology, with a particle size of ~5 µm. The Brunauer-Emmett-Teller surface areas of graphitic carbon and SiC were 28-150 and ~7.0 m2/g, respectively. We concluded that graphite and SiC were produced at this low sintering temperature because of the cobalt catalyst, which facilitated nanomixing of carbon and SiO2 by sandwiching the carbon films between the silicate layers.

Mucosal Immunity Related to FOXP3+ Regulatory T Cells, Th17 Cells and Cytokines in Pediatric Inflammatory Bowel Disease.

BACKGROUND: We aimed to investigate mucosal immunity related to forkhead box P3 (FOXP3+) regulatory T (Treg) cells, T helper 17 (Th17) cells and cytokines in pediatric inflammatory bowel disease (IBD). METHODS: Mucosal tissues from terminal ileum and colon and serum samples were collected from twelve children with IBD and seven control children. Immunohistochemical staining was done using anti-human FOXP3 and anti-RORγt antibodies. Serum levels of cytokines were analyzed using a multiplex assay covering interleukin (IL)-1ß, IL-4, IL-6, IL-10, IL-17A/F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, interferon (IFN)-γ, soluble CD40L, and tumor necrosis factor-α. RESULTS: FOXP3+ Treg cells in the lamina propria (LP) of terminal ileum of patients with Crohn's disease were significantly (P < 0.05) higher than those in the healthy controls. RORγt+ T cells of terminal ileum tended to be higher in Crohn's disease than those in the control. In the multiplex assay, serum concentrations (pg/mL) of IL-4 (9.6 ± 1.5 vs. 12.7 ± 3.0), IL-21 (14.9 ± 1.5 vs. 26.4 ± 9.1), IL-33 (14.3 ± 0.9 vs. 19.1 ± 5.3), and IFN-γ (15.2 ± 5.9 vs. 50.2 ± 42.4) were significantly lower in Crohn's disease than those in the control group. However, serum concentration of IL-6 (119.1 ± 79.6 vs. 52.9 ± 39.1) was higher in Crohn's disease than that in the control. Serum concentrations of IL-17A (64.2 ± 17.2 vs. 28.3 ± 10.0) and IL-22 (37.5 ± 8.8 vs. 27.2 ± 3.7) were significantly higher in ulcerative colitis than those in Crohn's disease. CONCLUSION: Mucosal immunity analysis showed increased FOXP3+ T reg cells in the LP with Crohn's disease while Th17 cell polarizing and signature cytokines were decreased in the serum samples of Crohn's disease but increased in ulcerative colitis.

Mesoporous silica-pillared H(+)-kenyaite with highly ordered gallery structure.

Mesoporous silica-pillared H(+)-kenyaite (SPK) derivatives with highly ordered gallery structure and thermal resistance were prepared by the hydrolysis of TEOS (tetraethylorthosilicate) in interlayer space, using DDA (dodecylamine) as catalyst and template. DDA-TEOS/H(+)-kenyaite intercalation compounds were obtained by the dispersion of H(+)-kenyaite in DDA-TEOS solution. DDA-TEOS/H(+)-kenyaites were hydrolyzed rapidly in pure water, forming siloxane pillared H(+)-kenyaites. Calcination of siloxane pillared H(+)-kenyaites for 5 h at 600 degrees C in air resulted in mesoporous SPK derivatives. These exhibited refractions corresponding to a basal spacing of 5.0-5.5 nm, a uniform pore size of 2.5-3.0 nm and large surface areas between 707 and 877 m2/g. TEM images confirmed that SPK had uniform interlayer spaces of 2.0-3.0 nm in agreement with the gallery height and pore size data. The structure and physical properties of SPK remained stable after heating for 5 h at 800 degrees C in air. This is attributed to the stable structure of kenyaite composed of 4-fold SiO4 tetrahedral sheets, and the formation of firm silica pillars.

Selective uranyl ion detection by polymeric ion-selective electrodes based on salphenH2 derivatives.

The new ion-selective electrodes (ISEs) based on salphenH2 derivatives such as N,N'-(propylenedioxy)benzenebis(salicylideneimine) L1 and N,N'-4,5-(propylenedioxy)benzenebis(3,5-di-tert-butylsalicylideneimine) L2 as cation carriers are developed for a uranyl ion. The combination of these new ionophores with tris(2-ethylhexyl)phosphate (TEHP) as a plasticizer particularly shows near Nernstian slope in the wide concentration range (1.0 x 10(-6) to 1.0 x 10(-2) M) of UO2(2+) and is observed well in the pH range from 1.0 to 5.0 with a response time less than 20s. Since the employed ionophores were confirmed to form well-defined stable 1:1 complexes with UO2(2+), the observed high selectivity for a uranyl ion over the other cations was attributed to the selective complexation as well as the lipophilic behavior of these ligands especially for L2. The proposed electrodes offered practically low detection limit of 6.5 x 10(-7) M and reasonably good end-points within experimental error were obtained when the sensor was used as an indicator electrode for the potentiometric titration.