MIL-101@g-C3N4 nanocomposite was prepared by solvothermal synthesis and used for CO2 adsorption. The parent materials (MIL-101 and g-C3N4) and the MIL-101@g-C3N4 were characterized by X-ray diffraction, argon adsorption/desorption, Fourier transform infrared spectroscopy, thermal analysis (TG/DTA), transmission electronic microscopy, and Energy-dispersive X-ray spectroscopy. The results confirmed the formation of well-defined MIL-101@g-C3N4 with interesting surface area and pore volume. Furthermore, both MIL-101 and MIL-101@g-C3N4 were accomplished in carbon dioxide capture at different temperatures (280, 288, 273 and 298 K) at lower pressure. The adsorption isotherms show that the nanocomposite has a good CO2 adsorption affinity compared to MIL-101. The best adsorption capacity is about 1.6 mmol g?1 obtained for the nanocomposite material which is two times higher than that of MIL-101, indicating strong interactions between CO2 and MIL-101@g-C3N4. This difference in efficacy is mainly due to the presence of the amine groups dispersed in the nanocomposite. Finally, we have developed a simple route for the preparation of an effective and new adsorbent for the removal of CO2, which can be used as an excellent candidate for gas storage, catalysis, and adsorption. 相似文献
Novel soy protein/polystyrene nanoblends with core‐shell structures were successfully prepared by introducing nano‐sized PS into soy protein through emulsion polymerization. The nanoblends showed core‐shell structures, with the core being of PS and the shell of sodium dodecane sulfonate and soy protein polypeptides, when investigated by electron microscopy. Nanoblends containing high levels of PS (>30%) exhibited characteristic infrared spectrum bands, X‐ray diffraction peak, and glass transition, since PS microsphere aggregated to form independent PS domains. Mechanical strength and water resistance were effectively improved by introducing PS. An effective structure‐performance relationship was thereby established to describe the nanoblends.
De novo design and chemical synthesis of proteins and their mimics are central approaches for understanding protein folding and accessing proteins with novel functions. We have previously described carbohydrates as templates for the assembly of artificial proteins, so-called carboproteins. Here, we describe the preparation and structural studies of three alpha-helical bundle carboproteins, which were assembled from three different carbohydrate templates and one amphiphilic hexadecapeptide sequence. This heptad repeat peptide sequence has been reported to lead to 4-alpha-helix formation. The low resolution solution structures of the three carboproteins were analyzed by means of small-angle X-ray scattering (SAXS) and synchrotron radiation circular dichroism (SRCD). The ab initio SAXS data analysis revealed that all three carboproteins adopted an unexpected 3+1-helix folding topology in solution, while the free peptide formed a 3-helix bundle. This finding is consistent with the calculated alpha-helicities based on the SRCD data, which are 72 and 68 % for two of the carboproteins. The choice of template did not affect the overall folding topology (that is for the 3+1 helix bundle) the template did have a noticeable impact on the solution structure. This was particularly evident when comparing 4-helix carboprotein monomers with the 2x2-helix carboprotein dimer as the latter adopted a more compact conformation. Furthermore, the clear conformational differences observed between the two 4-helix (3+1) carboproteins based on D-altropyranoside and D-galactopyranoside support the notion that folding is affected by the template, and subtle variations in template distance-geometry design may be exploited to control the solution fold. In addition, the SRCD data show that template assembly significantly increases thermostability. 相似文献
Over 50 years of research has sought to define the role dietary fat plays in cardiovascular disease (CVD) risk. Although optimal
dietary fat quantity has been keenly pursued over past decades, attention has recently centered on the value of dietary fat
quality. The purpose of the present review is to provide a critical assessment of the current body of evidence surrounding
efficacy of dietary monounsaturated fatty acids (MUFA) for reduction of traditional risk factors defining metabolic syndrome
(MetS) and CVD. Due to existing and emerging research on health attributes of MUFA rich diets, and to the low prevalence of
chronic disease in populations consuming MUFA rich Mediterranean diets, national dietary guidelines are increasingly recommending
dietary MUFA, primarily at the expense of saturated fatty acids (SFA). Consumption of dietary MUFA promotes healthy blood
lipid profiles, mediates blood pressure, improves insulin sensitivity and regulates glucose levels. Moreover, provocative
newer data suggest a role for preferential oxidation and metabolism of dietary MUFA, influencing body composition and ameliorating
the risk of obesity. Mounting epidemiological and human clinical trial data continue to demonstrate the cardioprotective activity
of the MUFA content of dietary fat. As the debate on the optimal fatty acid composition of the diet continues, the benefit
of increasing MUFA intakes, particularly as a substitute for dietary SFA, deserves considerable attention. 相似文献
We report a very simple synthesis strategy for the formation of moderately porous ionosilica materials containing ammonium groups. We synthesized an ionosilica xerogel and an ionosilica aerogel, either via conventional or supercritical work‐up. The synthesis scheme of both precursor and ionosilica materials could easily be up‐scaled to a 100 g scale. All syntheses and work‐up procedures are sustainable as no additional agent and very low quantities of solvents were used, and no additional purifications steps were necessary. Although both materials show excellent anion exchange properties for chromate adsorption, noticeable differences were found regarding the thermodynamics of the exchange process. We attribute these differences to different surface chemistries of the materials, induced by the different work‐up procedures. Due to the easy availability of high quantities of material, ionosilicas can be implemented as functional ion exchange materials in larger scale processes, thus opening new fields of applications. 相似文献
A calorimetric method is applied to determine the solar system performance by in-situ measured data. The heat store is interpreted as a calorimeter and the information on charge and discharge is extracted from the shape analysis of the heat store’s temperature profile. The method is applicable to any heating system which includes a heat store. In the present paper, this procedure is presented and applied to determine the solar gain for a large solar system for domestic hot water preparation and a solar combisystem. The uncertainty of this method is in the range of ±10%. The results obtained by the calorimetric method are compared to TRNSYS simulations. 相似文献
We have examined the esterification of [3H]cholesterol following the intratracheal instillation of a tracer amount into the isolated rat lung perfused with Krebs bicarbonate
containing 4.5% albumin. At 5, 30 and 60 min after instillation, lungs were lavaged at 2°C with 3×10 ml of 0.15 M NaCl, each
volume instilled and withdrawn three times. Each lung was lavaged at only one time point. The saline recovered was centrifuged
at 150 g (5 min) to sediment the macrophage-rich fraction, leaving the surfactant in the supernatant. The amounts and specific
activity of cholesterol and cholesteryl ester were measured following isolation by high performance liquid chromatography
of the free cholesterol and the hydrolyzed ester-derived cholesterol. There was a rapid fall in [3H]cholesterol in the surfactant fraction, accompanied by a reciprocal increase in [3H]cholesteryl ester. Likewise, there was a rapid increase in [3H]cholesteryl ester in the macrophage-rich fraction, while the level of free [3H]cholesterol in that fraction remained very low. These data are consistent with exogenous cholesterol being rapidly esterified
in the alveolus, and the ester then being cleared by the macrophages. We were unable to locate the actual site of esterification.
Lipids 相似文献
Alumina composites reinforced with 20 vol% SiC whiskers were exposed to applied stresses in four-point flexure at temperatures of 1000°, 1100°, and 1200°C in air for periods of up to 14 weeks. At 1000° and 1100°C, an "apparent" fatigue limit was established at stresses of ∼ 75% of the fast fracture strength. However, after long-term (>6 weeks) tests at 1100°C, some evidence of crack generation as a result of creep cavitation was detected. At 1200°C applied stresses as low as 38% of the 1200°C fracture strength were sufficient to promote creep deformation and accompanying cavitation and crack generation and growth resulting in failures in times of <250 h. 相似文献
A precursor of boron nitride was prepared through the partial condensation of 2,4,6-trichloroborazine and bis-(trimethylsilyl)acetylene. This reaction was conducted at 100°C and is catalyzed by AlCl3. The condensation product pyrolyzed at 800°C, producing trimethylsilyl chloride as a volatile product and a boron nitride rich residue containing 54 wt% of the initial weight. Mixtures of the precursor and commercial boron nitride were made and hot-pressed at 800°C and 27.6 MPa. A maximum density of 1.84 g/cm3 is reached at a loading corresponding to the deposition of 13 wt% residue derived from the precursor. Examination by analytical electron microscopy, including X-ray energy dispersive spectroscopy and electron energy loss spectroscopy analyses, revealed the location of material derived from the precursor in BN-binder composites through the presence of residual aluminum, silicon, and carbon. Crystallization of boron nitride from the precursor appears to have taken place, as deduced from the morphology of the phases observed and association with residual elements present in the binder. 相似文献
Pyrolysis of lignin is one approach that has been investigated to upgrade this material into higher value products. However, there have been relatively few efforts to quantitatively model these reactions. This paper describes a methodology for modeling lignin pyrolysis which has been extensively developed for related materials like coal. The samples are characterized using pyrolysis experiments under a standard set of conditions, where the products are analyzed by Fourier Transform Infrared (FT-IR) Spectroscopy and Field Ionization Mass Spectrometry (FIMS). Solvent extraction experiments are done to determine the extractables yields and elemental analysis is done to further constrain the model.
One lignin, produced from ethanol/water extraction of mixed hardwoods, was selected for the application of this modeling approach. The model was able to qualitatively predict the tar molecular weight distributions and quantitatively predict the variations of the gas and tar evolution rates and yields with heating rate for the calibration set of experiments. The model can be improved by more precise information on lignin structure, crosslinking chemistry, and tar transport mechanisms. It also needs to be validated by simulation of pyrolysis conditions at high heating rates and/or high pressures for which data is currently not available. 相似文献