Green Synthesis of MOF-801(Zr/Ce/Hf) for CO2/N2 and CO2/CH4 Separation.

The purification of natural gas and the removal of carbon dioxide from flue gases are crucial to economize precious resources and effectively relieve a series of environmental problems caused by global warming. Metal-organic framework (MOF) materials have demonstrated remarkable performance and benefits in the area of gas separation; however, obtaining materials with high gas capacity and selectivity simultaneously remains difficult. In addition, harsh synthesis conditions and solvent toxicity have been restricted in large-scale production and industrial application. Therefore, MOF-801(Zr/Ce/Hf) was created based on the green synthesis of the MOF-801 construction unit by altering the kinds of metal salts, and the impact of three metal nodes on the performance of gas adsorption and separation was demonstrated by contrasting the three MOFs. The results showed that MOF-801(Ce) has the best CO2 adsorption capacity (3.3 mmol/g at 298 K), which also was demonstrated with in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results, CO2/CH4 (ideal adsorbed solution theory (IAST) = 13.28 at 298 K, 1 bar, CO2/CH4 = 1:1, v/v), and the separation performance of CO2/N2 (IAST = 57.46 at 298 K, 1 bar, CO2/N2 = 1:1, v/v) among the group. Green synthesis of MOF-801(Zr/Ce/Hf) is an ideal candidate for flue gas separation and methane purification because of its high regeneration capacity and strong cyclic stability.

Effect of different ionic liquids and organic solvents on the structural and physicochemical properties of cellulose-protein complexes extracted from Se-enriched peanut leaves.

Abundant cellulose and insoluble protein were contained in the Se-enriched peanut leaf residue, a by-product from leaf protein extraction. Ionic liquids (ILs) were used to extract the cellulose-protein complexes (CPCs) from Se-enriched peanut leaf residue. The effects of various ILs as extractants and organic solvents as regenerant on the physicochemical properties of CPCs were compared. The results showed that the yield of CPCs and recovery yield of [AMIM]Cl (1-allyl-3-methylimidazole chloride) were better than those of [BMIM]Cl (1-butyl-3-methylimidazolium chloride). Simultaneously, it could be seen from the infrared absorption peaks and secondary structure fitting results that [BMIM]Cl seemed stronger than [AMIM]Cl in destroying the secondary structure of CPCs. Scanning electron microscope (SEM) showed that the CPCs extracted by [BMIM]Cl were lamellate with holes on the surface, and the CPCs extracted by [AMIM]Cl were rough, almost without holes on the surface. Furthermore, the transmittance and tensile strength of the film which contained BA-CPC ([BMIM]Cl as extractant and acetonitrile as regenerant) film were better than those contained AA-CPC ([AMIM]Cl as extractant and acetonitrile as regenerant) film, which might be mainly because the types of ILs and regenerants affect the particle size of CPCs, thereby influencing the mechanical properties of the film.

Se-O Bond Is Unique to High Se Enriched Sweet Potato Stem Protein with Better Antioxidant Ability.

Sweet potato plants were treated with selenium (Se). Spraying Se on the sweet potato leaves was an effective Se enrichment method and proteins were extracted from the sweet potato stem. The structural characteristics of the protein were investigated. Fourier transform infrared spectroscopy (FT-IR) detected more signals from the Se-enriched sweet potato stem protein (SSP), and the number of forms of Se chemical bonds gradually increased with increasing Se content, such as the Se-O bond in high Se-enriched SSP, indicating altered secondary structures.Scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) indicated more Se atoms in the Se-enriched SSPs (SSSPs). The DSC results revealed that Se enrichment enhanced the thermal stability of the samples. Moreover, selenomethionine (SeMet), selenocystine (SeCys2), and methylselenocysteine (MeSeCys) were determined to be the main Se forms in the SSSPs. Furthermore, the SSSPs showed relatively higher superoxide anion radical and DPPH radical scavenging activities than the blank, which indicates that SSSPs can be used as antioxidants. By recovering the proteins, the agricultural by-product-sweet potato stem can be further utilized, and the obtained Se-enriched proteins may contribute to human health.

Foliar application is an effective method for incorporating selenium into peanut leaf proteins with antioxidant activities.

Proteins were extracted from Se-enriched peanut leaves, an agro-byproduct, and the foliar application of sodium selenite was indicated to be an effective method to incorporate Se into leaf selenoproteins with 75-80% incorporation rates. After trypsin digestion, the most abundant proteins from Se-enriched peanut leaf (PSPL) were identified as pathogenesis-related class 10 proteins, Ara h 8 allergen and its isoforms, using LC-MS/MS. The Se species in both the low Se PSPL and high Se PSPL were determined to be selenomethionine (SeMet), methylselenocysteine (MeSeCys) and selenocystine (SeCys2) with SeMet (15.6 mg/g) dominated the high Se PSPL. Their antioxidant activities were also evaluated using free radical scavenging assay, reducing power assay and ferric thiocyanate (FTC) test. As results, the PSPL exhibited potent DPPH radical (96.2%) and superoxide anion radical (98.4%) scavenging activities and showed strong reducing power in a Se-concentration-dependent manner, indicating that PSPL can be used as antioxidants and Se sources to improve health.

Robust high-connected rare-earth MOFs as efficient heterogeneous catalysts for CO2 conversion.

Two series of chemically and thermally stable rare-earth MOFs were constructed using trinuclear [M3(µ3-OH)(COO)6] SBUs and linear dicarboxylate linkers, which feature three-dimensional 12-connected frameworks with an hcp topology. These materials contain a large density of Lewis acidic sites, leading to high catalytic activity towards the cycloaddition of CO2 and epoxides under mild conditions.

Involvement of NADPH oxidases in alkali burn-induced corneal injury.

Chemical burns are a major cause of corneal injury. Oxidative stress, inflammatory responses and neovascularization after the chemical burn aggravate corneal damage, and lead to loss of vision. Although NADPH oxidases (Noxs) play a crucial role in the production of reactive oxygen species (ROS), the role of Noxs in chemical burn-induced corneal injury remains to be elucidated. In the present study, the transcription and expression of Noxs in corneas were examined by RT-qPCR, western blot analysis and immunofluorescence staining. It was found that alkali burns markedly upregulated the transcription and expression of Nox2 and Nox4 in human or mouse corneas. The inhibition of Noxs by diphenyleneiodonium (DPI) or apocynin (Apo) effectively attenuated alkali burn-induced ROS production and decreased 3-nitrotyrosine (3-NT) protein levels in the corneas. In addition, Noxs/CD11b double­immunofluorescence staining indicated that Nox2 and Nox4 were partially co-localized with CD11b. DPI or Apo prevented the infiltration of CD11b-positive inflammatory cells, and inhibited the transcription of inflammatory cytokines following alkali burn-induced corneal injury. In our mouse model of alkali burn-induced corneal injury, corneal neovascularization (CNV) occurred on day 3, and it affected 50% of the whole area of the cornea on day 7, and on day 14, CNV coverage of the cornea reached maximum levels. DPI or Apo effectively attenuated alkali burn­induced CNV and decreased the mRNA levels of angiogenic factors, including vascular endothelial growth factor (VEGF), VEGF receptors and matrix metalloproteinases (MMPs). Taken together, our data indicate that Noxs play a role in alkali burn-induced corneal injury by regulating oxidative stress, inflammatory responses and CNV, and we thus suggest that Noxs are a potential therapeutic target in the future treatment of chemical-induced corneal injury.

[Data analysis of laser desorption/ionization mass spectrum of individual particle using adaptive resonance theory based neural network].

On-line measurement of size and chemical composition of single particle using an aerosol laser time-of-flight mass spectrometer (ALTOFMS) was designed in our lab. Each particle's aerodynamic diameter is determined by measuring the delay time between two continuous-wave lasers operating at 650 nm. A Nd : YAG laser desorbs and ionizes molecules from the particle, and the time-of-flight mass spectrometer collects a mass spectrum of the generated ions. Then the composition of single particle is obtained. ALTOFMS generates large amount of data during the process period. How to process these data quickly and extract valuable information is one of the key problems for the ALTOFMS. In the present paper, an adaptive resonance theory-based neural network, ART-2a algorithm, was used to classify mixed mass spectra of aerosol particles of NaCl, CaCl2, dioctylphthalate (DOP), and 2,5-dihydroxybenzoic acid (DHB). Compared with the traditional methods, ART-2a can recognize input patterns self-organically, self-adaptively and self-steadily without considering the complexity and the number of the patterns, so it is more favorable for the analysis of the mass spectra data. Experimental results show that when vigilance parameter is 0.40, learning rate is 0.05 and iteration number is 6, ART-2a algorithm can successfully reveal these four particle categories. The weight vectors for these four particle classes were obtained, which can represent the characters of these four particle classes remarkably.

[Data analysis of laser desorption/ionization mass spectrum of atmospheric aerosol particles using fuzzy clustering algorithms].

On-line measurement of size and composition of single particle using an aerosol time-of-flight Laser mass spectrometry (ATOFLMS) had been designed in our lab. Each particle's aerodynamic diameter is determined by measuring the delay time between two continuous-wave lasers, A Nd : YAG laser desorbs and ionizes molecules from the particle, and the time-of-flight mass spectrometer collects a mass spectrum of the generated ions. Then the composition of single particle is obtained. ATOFLMS generates large amount of data during the process period. How to process these data and extract valuable information is one of the key problems for the ATOFLMS. In this paper, the fuzzy clustering used to classify large numbers of mass spectral of air indoor by an ATOFLMS. Each revised spectrum is converted to a normalized 300-point vector, each point representing one mass unit. Then the positive ion mass spectra of a single particle are described as 300-dimensional data vectors using the ion masses as dimensions and the ion signal peak areas as values. The data vectors of all particles measured are written into a classification matrix. Each spectrum's data was stored as one row in this matrix. The Fuzzy c-means algorithm is an iterative method starting the calculation with random class centers to find a substructure in the data. The procedure works in such a way that finally similar objects (particle spectra) have a minimum distance between their corresponding data vectors, on the one hand, and to the center of a cluster, on the other hand. So the aim of the iteration is to find local minima in the N-dimensional space where N is the number of evaluated peak masses. The particle data used in this study were collected over a period one day in Hefei. During the campaign, inorganic salts, mineral particles, and carbonaceous particles, with varying degrees of secondary components, were identified. The detection results of particle size exhibit that aerosol is predominanantly in the form of fine particles, and the particles whose diameter larger than 1 microm are scare. The particles whose diameter less than 1 microm are make up of 95% of the total particles, and these particles are major distributed in 0.4-0.8 microm.

[Single particle measurement of suspended soil dust using laser desorption/ionization time-of-flight mass spectrometry].

Real-time measurement of size and composition of single soil dust particles using an aerosol time-of-flight laser mas spectrometry (ATOFLMS) was designed in our lab. Each particle's aerodynamic diameter was determined by measuring the delay time between two continuous-wave lasers, a Nd:YAG laser with a 266 nm pulsed output was used to desorb and ionize aerosol particles, and ions formed in the laser desorption/ionization process were accelerated into the time-of-flight drift region where they separated by mass-to-charge ratio, then the composition of single particle was obtained. In the present paper, soil samples were collected from four different areas in China. After the pretreatment and suspension, the particle sample was then transferred to ATOFLMS through a plastic transfer line. During the campaign, a large number of size and mass spectra of single par ticles were obtained. The presence of crustal elements was observed in the mass spectra of individual particles. Iron, potassium aluminum and calcium constitute the two most commonly detected cations. Other common cations observed in the mass spectra o soil particles include magnesium, and sodium. The detection results exhibit that the coarse particles with size of 1-2 microm are dominate in the detected particles. Experimental results show the ATOFLMS have important practical value for researching and monitoring of atmospheric aerosol environment.