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Controlled synthesis of mesoporous materials with ultracomplicated pore configurations is of great importance for both fundamental research of nanostructures and the development of novel applications. IBN-9, which is the only tricontinuous mesoporous silica with three sets of interpenetrating three-dimensional channel systems, appears to be an excellent model mesophase for such study. The extensive study of synthesis space diagrams proves mesophase transition among the cylindrical MCM-41, tricontinuous IBN-9 and bicontinuous MCM-48, and also allows a more precise control of phase-pure synthesis. On the other hand, rational design of structure-directing agents offers a possibility to extend the synthesis conditions of IBN-9, as well as tailor its pore size. Moreover, an unprecedented helical structure consisting of twisted 3-fold interwoven mesoporous channels is reported here for the first time. The unique tricontinuous mesostructure of IBN-9 has been well-replicated by other functional materials (e.g., carbon and platinum) via a “hard-templating” synthesis route. The obtained carbon material possesses large surface area (∼1900 m2/g), high pore volume (1.56 cm3/g), and remarkable gas adsorption capability at both cryogenic temperatures and room temperature. The platinum material has an ordered mesostructure composed of highly oriented nanocrystals. [ABSTRACT FROM AUTHOR]

Ordered porous materials with unique pore structures and pore sizes in the mesoporous range (2–50 nm) have many applications in catalysis, separation and drug delivery. Extensive research has resulted in mesoporous materials with one-dimensional, cage-like and bi-continuous pore structures. Three families of bi-continuous mesoporous materials have been made, with two interwoven but unconnected channels, corresponding to the liquid crystal phases used as templates. Here we report a three-dimensional hexagonal mesoporous silica, IBN-9, with a tri-continuous pore structure that is synthesized using a specially designed cationic surfactant template. IBN-9 consists of three identical continuous interpenetrating channels, which are separated by a silica wall that follows a hexagonal minimal surface. Such a tri-continuous mesostructure was predicted mathematically, but until now has not been observed in real materials. [ABSTRACT FROM AUTHOR]

A series of novel mesoporous silica materials with ultra-large pores (20 to 40 nm in size), interconnected channel structure, thick walls (15 to 20 nm), high hydrothermal stability and selective protein adsorption were synthesized viaa new synthetic strategy. We used Brij-56 and Brij-97 as templates and ethyl acetate (EA) and dimethyl o-phthalate (DOP) as additives in a neutral pH system to afford three novel spherical mesoporous silica materials (denoted as B56-E-20, B56-D-33 and B97-D-40) having controllable, interconnected mesoscale channels with diameters of 20, 33 and 40 nm, respectively. The products have shown effective performance in size-selective adsorption of biomacromolecules, demonstrating great potentials in biomacromolecular separation. The molecular weight ranges of the proteins selectively adsorbed in B56-E-20, B56-D-33 and B97-D-40 are 50–55, 60–65 and 70–100 KDa, respectively. Moreover, the products show good hydrothermal stability and can maintain the mesostructure in boiling water over 5 days. This work has bridged the gap in the synthesis of ultra-large pore between mesoporous and macroporous biomaterials and their application in biomacromolecular separation. [ABSTRACT FROM AUTHOR]

AbstractRecent reports suggest that staphylococcal exotoxins, acting as superantigens, activate T cells with subsequent massive proliferation, thereby contributing to the etiology of chronic rhinosinusitis with nasal polyps (CRSwNP). The objectives of this study are (1) to demonstrate directly the presence of staphylococcal exotoxins in nasal mucosa and sinonasal polyp tissue, and (2) provide indirect evidence of the effect of superantigens on the T cells expressing the target of superantigen, i.e., the β variable chain receptor (TCRBV) in polyp tissue and peripheral blood of patients with CRSwNP. Sinonasal polyp tissue and peripheral blood specimens were obtained from 37 patients with chronic rhinosinusitis (22 patients with bilateral nasal polyps, 15 without nasal polyps) and 12 normal subjects for comparative negative controls. Tissue specimens were assayed by enzyme-linked immunosorbent assay (ELISA) for the most common staphylococcal exotoxins (A–D) and toxic shock syndrome toxin type 1. Fresh tissue and blood samples were analyzed by flow cytometry to determine the expression of TCRBV. In the CRSwNP subjects 12 of 22 samples (54.54) demonstrated reactivity for at least 1 staphylococcal exotoxin, while 2 of the 12 were positive for 2 toxins. There were no positive results in the CRS without nasal polyps or control groups. There was a clear trend of increased TCRBV expression in the ELISA-positive group both for tissue and blood specimens. Staphylococcal superantigens were present in the nasal cavity of patients with CRSwNP with a high percentage of TCRBV, which suggests the possibility of superantigens as etiological agents of CRSwNP.Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Significant internal quantum efficiency (IQE) enhancement of GaN/AlGaN multiple quantum wells (MQWs) emitting at ~350 nm was achieved via a step quantum well (QW) structure design. The MQW structures were grown on AlGaN/AlN/sapphire templates by metal-organic chemical vapor deposition (MOCVD). High resolution x-ray diffraction (HR-XRD) and scanning transmission electron microscopy (STEM) were performed, showing sharp interface of the MQWs. Weak beam dark field imaging was conducted, indicating a similar dislocation density of the investigated MQWs samples. The IQE of GaN/AlGaN MQWs was estimated by temperature dependent photoluminescence (TDPL). An IQE enhancement of about two times was observed for the GaN/AlGaN step QW structure, compared with conventional QW structure. Based on the theoretical calculation, this IQE enhancement was attributed to the suppressed polarization-induced field, and thus the improved electron–hole wave-function overlap in the step QW. [ABSTRACT FROM AUTHOR]

A hexagonal mesoporous aluminophosphate with high thermal stability (JLU-50) is successfully synthesized from the assembly of preformed aluminophosphate precursors with a cationic surfactant cetyltrimethylammonium bromide (CTAB) by a two-step procedure. [ABSTRACT FROM AUTHOR]