Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: HUMANGGP:030791 (MCM)
 2,348 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Composite material formed from a mesoporous aluminosilicate, Na-AlMCM-41, with conducting polyaniline (PANI) has been synthesized by an in situ polymerization technique. Studies of aniline adsorption over mesoporous Na-AlMCM-41 synthesized in our laboratory allowed us to find the modes in which aniline interacts with the active sites of Na-AlMCM-41. In order to obtain the best reaction conditions to polymerize aniline onto Na-AlMCM-41, aniline was first polymerized to produce pure PANI. Hence, the oxidative in situ polymerization was carried out by two procedures, differing in the polymerization time and in static or stirring conditions. Studies of infrared spectroscopy and UV-vis spectroscopy indicated that higher polymerization time and static conditions allowed us to obtain mainly polyaniline in emeraldine form on the host. The N(2) isotherm of the polyaniline/Na-AlMCM-41 composite (PANI/MCM) indicated that the shape was similar to that of MCM, but the shift to saturation transition to lower partial pressure shows that the channels are occupied by PANI and they are now narrowed. The thermal properties of PANI, Na-AlMCM-41, and composite were investigated by TGA analyses and we found that the polymer shows higher thermal stability when it is forming the composite. Scanning electron microscopy indicated that PANI is not on the outer surface of the host. Conductivity studies show that PANI/Na-AlMCM-41 exhibits semiconductor behavior at room temperature and its conductivity was 7.0 x 10(-5) S/cm, smaller than that of pure polyaniline. PANI/Na-AlMCM-41 conductivity shows an increase as temperature increases. Magnetic measurements at room temperature confirmed that the composite has paramagnetic behavior; at lower temperatures the composite became diamagnetic.
 ...
PMID:Preparation and characterization of polyaniline-containing Na-AlMCM-41 as composite material with semiconductor behavior. 1605 56

Four different types of amine-attached MCM-48 silicas were prepared and investigated for CO(2) separation from N(2). Monomeric and polymeric hindered and unhindered amines were attached to the pore surface of the MCM-48 silica and characterized with respect to their CO(2) sorption properties. The pore structures and amino group content in these modified silicas were investigated by XRD, FT-IR, TGA, N(2) adsorption/desorption at 77 K and CHN/Si analysis, which confirmed that in all cases the amino groups were attached to the pore surface of MCM-48 at 1.5-5.2 mmol/g. The N(2) adsorption/desorption analysis showed a considerable decrease of the pore volume and surface area for the MCM-48 silica containing a polymeric amine (e.g., polyethyleneimine). The CO(2) adsorption rates and capacities of the amine-attached MCM-48 samples were studied employing a sorption microbalance. The results obtained indicated that in addition to the concentration of surface-attached amino groups, specific interactions between CO(2) and the surface amino groups, and the resultant pore structure after amine group attachment have a significant impact on CO(2) adsorption properties of these promising adsorbent materials.
 ...
PMID:Tailoring pore properties of MCM-48 silica for selective adsorption of CO2. 1685 99

Ce-containing MCM-41 materials were prepared via a direct, nonhydrothermal method at room temperature from tetra-ethoxysilane, n-hexadecyl trimethyl ammonium bromide, ammonia solution, and cerium(IV) ammonium nitrate precursors. Composite materials containing the nominated ratios of 5 and 10% (w/w) CeO2/MCM-41 were targeted. The obtained materials were investigated by TGA, DSC, FTIR, diffuse reflectance UV-vis, XRD, N2 adsorption/desorption isotherms, and SEM. Results indicated the insertion of cerium ions in tetrahedral environment in the framework of MCM-41. BET surface area amounting to 824 and 726 m2/g; total pore volume amounting to 0.427 and 0.515 cm3/g; and narrow pore size distribution maximizing at 22.5 and 23.7 A, respectively were obtained for the 5 and 10% CeO2/MCM-41 calcined composites. SEM showed a spherical type morphology for the composites which is rather similar to their blank MCM-41, and no clear ceria aggregates were observed on the external surfaces of composites spherical particles. Thus, the adopted method allows the persistence of MCM-41 texture with cerium inserts in the framework of MCM-41 and/or forms finely divided ceria nanoparticles on the wall of MCM-41 materials. Moreover, stabilization of any formed ceria nanoparticles was attributed to the short nonintersecting porous nature of MCM-41 matrix, which hinders their aggregation upon calcinations.
 ...
PMID:Cerium modified MCM-41 nanocomposite materials via a nonhydrothermal direct method at room temperature. 1771 29

Fluorescent materials (Q)(3-n)(2-BuO)(n)Al (Q = 8-hydroxyquinoline, 2-methyl-8-hydroxyquinoline and 5-chloro-8-hydroxyquinoline, n = 1 or n = 2) were prepared in toluene by reacting aluminum 2-butoxide with 8-hydroxyquinoline and its derivatives. The compounds were characterized by (1)H, (13)C and (27)Al NMR in solution, and the coordination status of the aluminum atom in the complexes were determined by (27)Al NMR chemical shifts. The compounds were grafted on mesoporous silica (MCM-41) at room temperature without isolation of the complexes. The prepared materials were characterized by elemental analysis, FT-IR spectroscopy, low-angle X-ray diffraction (XRD), thermal analysis (TGA/DSC) and N(2) adsorption and desorption measurements. The results showed that the characteristic mesoporous structure of MCM-41 after grafting aluminum complexes remains intact. The photoluminescence (PL) properties of (Q)(3-n)(2-BuO)(n-1)@Al-MCM-41 were investigated. The results revealed that the maximum wavelength is modulated by the MCM-41 guest.
 ...
PMID:Grafting aluminum(III) 8-hydroxyquinoline derivatives on MCM-41 mesoporous silica for tuning of the light emitting color. 2038 Oct 55

An inorganic/organic hybrid adsorbent for phosphate adsorption was synthesized by introducing lanthanum (La) onto diamino modified MCM-41. The adsorbent was characterized by XRD, SEM, BET, TGA, and FTIR spectroscopy. A series of batch tests were conducted to investigate the influence of contact time, initial phosphate concentration, pH of the solution, and competitive ions on the phosphate adsorption capacity. The Langmuir and Freundlich models were used to simulate the sorption equilibrium, and the results indicated that the Langmuir model fitted the experiment data better than the Freundlich model. The maximum adsorption capacity calculated from the Langmuir model is 54.3 mg/g. For kinetic study, phosphate adsorption followed the pseudo-second-order equation well with a correlation coefficient greater than 0.99. Optimum pH value for the removal of phosphate was between 3.0 and 7.0. The presence of Cl(-) and NO(3)(-) has neglectable influence on the phosphate adsorption. F(-)and SO(4)(2-) have negative effects on the adsorption of phosphate. Phosphate on the spent adsorbent can be almost released by 0.01 M NaOH solution in 12 min.
 ...
PMID:Adsorption behavior of phosphate on lanthanum(III)-coordinated diamino-functionalized 3D hybrid mesoporous silicates material. 2113 Nov 25

In the present study, a new encapsulation technique for corrosion inhibitor is proposed. The hollow mesoporous silica spheres (HMSs) were synthesized by the co-templates method as nanocontainers for corrosion inhibitor, benzotriazole (BTA) and the supramolecular nanovalves, consisting of cucurbit[6]uril (CB[6]) rings and the functional stalks attached to the surface of HMSs achieved on-demand release. The synthesis process of HMSs and the assembly process of the nanovalves were confirmed by SEM, TEM, N(2) adsorption/desorption, FTIR, TGA and solid-state (13)C CP/MAS NMR. The encapsulation capacity and release characteristics of BTA-loaded, assembled HMSs were investigated. The HMSs assembled with the nanovalves possessed a higher encapsulation capacity for BTA than MCM-41 assembled under the same procedure due to its huge hollow internal structure. The pH-controlled release properties of BTA from the assembled HMSs under different pH environments were monitored by ultraviolet absorption spectra. The release profiles showed that there was almost no leakage of BTA from the assembled HMSs in neutral solution, while in alkaline solution BTA released very quickly, and the release rate increased with increasing pH values. Such a property makes the HMSs assembled with the pH-responsive nanovalves have great potential applications in smart anticorrosion coatings.
 ...
PMID:pH-responsive nanovalves based on hollow mesoporous silica spheres for controlled release of corrosion inhibitor. 2259 78

As part of a recent research effort aimed at employing mesoporous materials for controlled drug delivery, this paper presents MCM-41 as a carrier for topical application, using Trolox as a model unstable guest molecule. The complexes between Trolox and MCM-41 were prepared by employing different inclusion procedures, varying solvent, method and pretreatment of the silica matrix. The objectives of this study were to determine Trolox loading, analyze its integrity and availability after immobilization on mesoporous silica, evaluate MCM-41 influence on Trolox photodegradation and establish whether the preparation method significantly influences complex properties. The characterization analyses (XRD, TGA, DSC and FTIR) confirmed the hydrogen-bonding interaction and Trolox structure preservation. Gas-volumetric analysis showed a consistent decrease in surface area and in pore volume and diameter with respect to bare MCM-41 indicating that Trolox was mainly located within mesopores. In vitro diffusion tests showed a slower release of Trolox after inclusion in the MCM-41 matrix; at the same time UV irradiation studies highlighted an increased photostability for the complex particularly in O/W emulsion. Moreover the radical scavenging activity of Trolox was maintained after immobilization. In all cases, differences were observed in all tested samples, suggesting that results could be optimized by modifying the inclusion procedure and by improving the guest loading.
 ...
PMID:Mesoporous silica as a carrier for topical application: the Trolox case study. 2278 59

This work reports a new method to covalently attach calix[4]arene derivatives onto MCM-41, using a diisocyanate as a linker. The modified mesoporous silicates were characterized by fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA) and elemental analysis. The FTIR spectra and TGA analysis verified that the calix[4]arene derivates are covalently attached to the mesoporous silica. The preservation of the MCM-41 channel system was checked by X-ray diffraction and nitrogen adsorption analysis.
 ...
PMID:Synthesis and characterization of mesoporous silica functionalized with calix[4]arene derivatives. 2320 77

Antioxidants can prevent UV-induced skin damage mainly by neutralizing free radicals. For this purpose, quercetin (Q) is one of the most employed flavonoids even if the potential usefulness is limited by its unfavorable physicochemical properties. In this context, mesoporous silica (MCM-41) is herein proposed as a novel vehicle able to improve the stability and performance of this phenolic substrate in topical products. Complexes of Q with plain or octyl-functionalized MCM-41 were successfully prepared with different weight ratios by a kneading method, and then, they were characterized by XRD, gas-volumetric (BET), TGA, DSC, and FTIR analyses. The performances of the different complexes were evaluated in vitro in terms of membrane diffusion profiles, storage and photostability, antiradical and chelating activities. The physicochemical characterization confirmed an important host/guest interaction due to the formation of Si-OH/quercetin hydrogen-bonded adducts further strengthened by octyl functionalization through van der Waals forces. The immobilization of Q, particularly on octyl-functionalized silica, increased the stability without undermining the antioxidant efficacy opening the way for an innovative employment of mesoporous composite materials in the skincare field.
 ...
PMID:Stabilization of quercetin flavonoid in MCM-41 mesoporous silica: positive effect of surface functionalization. 2324 87

Novel terpyridine-functionalized MCM-41 nanoporous silica was synthesized and characterized by X-ray powder diffraction (XRD), infrared (IR) spectroscopy, transmission electron microscopy (TEM), and thermal (TGA-DSC) and elemental analyses. The application of functionalized nanoporous silica was investigated for the removal of chromate, which is one of the most harmful pollutants in the environment. The effects of several parameters including the sample pH, adsorption kinetic and maximum adsorption capacity of functionalized nanoporous silica in the removal of chromate were studied.
 ...
PMID:Chromate removal using novel modified MCM-41 nanoporous silica: synthesis and characterization of novel terpyridine-modified MCM-41. 2384 41


1 2 3 Next >>