Large and Highly Selective and Permeable CHA Zeolite Membranes

Large (100 cm2 membrane area) tubular chabazite (CHA) zeolite membranes (450 nm thick) were experimentally evaluated for the separation of CO2/CH4 in an industrial laboratory. An industrially relevant feed flow rate of 250 Ndm3/min was used. The feed pressure and temperature were varied in the ranges of 5–18 bar and 292–318 K, respectively. For a CO2/CH4 feed with a molar ratio of 1:1, the experimental CO2/CH4 selectivity was high at 205, and the CO2 permeance arrived at 52 × 10–7 mol/(m2·s·Pa) at 5 bar and 292 K. As far as we know, there is no report in the literature on large CHA membranes with such high permeability and selectivity. A high CO2/CH4 selectivity was also observed for a 1:4 CO2/CH4 feed. However, as indicated by mathematical modeling, concentration polarization was still an issue for membrane performance, especially at high operating pressures, even though the flow rate of the feed was relatively high. Without concentration polarization, the theoretical CO2/CH4 selectivity was 41% higher than the experimental value for a 1:1 CO2/CH4 feed at 18 bar. The corresponding CO2 permeance without concentration polarization was 23% higher than the experimentally observed value, reaching 34 × 10–7 mol/(m2·s·Pa). CHA membrane processes for the removal of CO2 from CH4 were designed, and the electricity consumption and module cost of the process were also estimated. All of the results in this study indicate a great potential of the large CHA membranes for biogas and natural gas upgrading; however, concentration polarization should be minimized in industrial processes

Bond Order Conservation Strategies in Catalysis Applied to the NH₃ Decomposition Reaction

On the basis of an extensive set of density functional theory calculations, it is shown that a simple scheme provides a fundamental understanding of variations in the transition state energies and structures of reaction intermediates on transition metal surfaces across the periodic table. The scheme is built on the bond order conservation principle and requires a limited set of input data, still achieving transition state energies as a function of simple descriptors with an error smaller than those of approaches based on linear fits to a set of calculated transition state energies. We have applied this approach together with linear scaling of adsorption energies to obtain the energetics of the NH₃ decomposition reaction on a series of stepped fcc(211) transition metal surfaces. This information is used to establish a microkinetic model for the formation of N₂ and H₂, thus providing insight into the components of the reaction that determines the activity

Serum biochemical parameters in different groups (mean ±SD).

<p>*<i>p</i><0.05 <i>vs</i> Sham operation group;</p><p>**<i>p</i><0.05 <i>vs</i> I/R group.</p><p>Serum biochemical parameters in different groups (mean ±SD).</p

Polyethylene Glycol-Mediated High-Performance Mixed Matrix Membranes via a “Nesting Effect” for CO₂ Separation

Various metal–organic framework (MOF)-based porous nanomaterials have been adopted to fabricate mixed matrix membranes (MMMs) aiming at breaking through the Robeson upper bound of individual polymer membranes for gas separation. However, the insufficient compatibility between the polymeric matrix and MOF nanofillers limits the further improvement of their gas separation performance. To overcome this challenge, we constructed relatively ideal Pebax/PEG/NH2–UiO-66 mixed matrix membranes inspired by θ solvent theory of polymer solutions. Polyethylene glycol (PEG) molecules were introduced to selectively swell the polar poly(tetramethylene oxide) (PTMO) domains of the Pebax matrix via hydrophobic–hydrophilic interactions and in turn furnished dispersed “nests” for NH2–UiO-66 nanofillers with polar nature to reduce the interparticle agglomeration (PEG nesting effect). MOF nanofillers tended to be relatively undisturbed, in which either the rigidity of polymer chains or the pore blocking of MOFs seen in unideal MMMs was restricted. The PEG “nesting effect” proposed herein could bring benefits to further improve the allowed maximum loading capacity of MOF nanofillers as well as adjust the interactions therein and therefore maximize the CO2 separation performance of Pebax/PEG/NH2–UiO-66 MMMs. Compared with individual Pebax membranes, Pebax/PEG/NH2–UiO-66 with a 15 wt % loading of NH2–UiO-66 showed a 73% higher CO2 permeability (210 barrer) and a 220% higher CO2/N2 selectivity (130), which demonstrated the most dramatical increases among Pebax-based MMMs until now and as well significantly exceeded the Robeson upper bound. Therefore, the proposed PEG “nesting effect” for the preparation of θ-type MMMs holds promising potential for membrane-based carbon capture and is possibly extended to the preparation of other MMMs

Expression of HIFα mRNA in rat livers.

<p>(A) HIFα mRNA levels were determined by real-time RT-PCR. Relative fold induction for HIFα mRNA (means ±SD) in I/R and RES group rat livers is presented relative to the expression in Sham operation group rat livers (*<i>P</i><0.05 compared with I/R group). (B) Western blot analysis for HIFα protein expression in the indicated groups. β-actin was used as a loading control.</p

A set of primers of HA and NA genes of H3N2 viruses.

<p>A set of primers of HA and NA genes of H3N2 viruses.</p

Charged amino acid variability related to N-glyco -sylation and epitopes in A/H3N2 influenza: Hem -agglutinin and neuraminidase

<div><p>Background</p><p>The A/H3N2 influenza viruses circulated in humans have been shown to undergo antigenic drift, a process in which amino acid mutations result from nucleotide substitutions. There are few reports regarding the charged amino acid mutations. The purpose of this paper is to explore the relations between charged amino acids, N-glycosylation and epitopes in hemagglutinin (HA) and neuraminidase (NA).</p><p>Methods</p><p>A total of 700 HA genes (691 NA genes) of A/H3N2 viruses were chronologically analyzed for the mutational variants in amino acid features, N-glycosylation sites and epitopes since its emergence in 1968.</p><p>Results</p><p>It was found that both the number of HA N-glycosylation sites and the electric charge of HA increased gradually up to 2016. The charges of HA and HA₁ increased respectively 1.54-fold (+7.0 /+17.8) and 1.08-fold (+8.0/+16.6) and the number of NGS in nearly doubled (7/12). As great diversities occurred in 1990s, involving Epitope A, B and D mutations, the charged amino acids in Epitopes A, B, C and D in HA₁ mutated at a high frequency in global circulating strains last decade. The charged amino acid mutations in Epitopes A (T₁₃₅K) has shown high mutability in strains near years, resulting in a decrease of NGT_135-135. Both K₁₅₈N and K₁₆₀T not only involved mutations charged in epitope B, but also caused a gain of NYT_158-160. Epitope B and its adjacent N-glycosylation site NYT_158-160 mutated more frequently, which might be under greater immune pressure than the rest.</p><p>Conclusions</p><p>The charged amino acid mutations in A/H3N2 Influenza play a significant role in virus evolution, which might cause an important public health issue. Variability related to both the epitopes (A and B) and N-glycosylation is beneficial for understanding the evolutionary mechanisms, disease pathogenesis and vaccine research.</p></div

Charged amino acid mutations on HA epitopes in variants/vaccine strains.

<p>Nine variants/vaccine strains were analyzed and only charged amino acids included. Both acidic amino acids [Aspartic acid (D) and Glutamic acid (E)] and basic amino acids [Lysine (K), Arginine (R) and Histidine (H)] labeled in different colors. The epitopes identified referred to Reference 7, 14 and the article (Lees WD, et al. J Virol. 2011. doi: <a href="https://doi.org/10.1128/JVI.00579-11" target="_blank">10.1128/JVI.00579-11</a>).</p

Uncovering the Molecular Mechanism of Actions between Pharmaceuticals and Proteins on the AD Network

<div><p>This study begins with constructing the mini metabolic networks (MMNs) of beta amyloid (Aβ) and acetylcholine (ACh) which stimulate the Alzheimer’s Disease (AD). Then we generate the AD network by incorporating MMNs of Aβ and ACh, and other MMNs of stimuli of AD. The panel of proteins contains 49 enzymes/receptors on the AD network which have the 3D-structure in PDB. The panel of drugs is formed by 5 AD drugs and 5 AD nutraceutical drugs, and 20 non-AD drugs. All of these complexes formed by these 30 drugs and 49 proteins are transformed into dyadic arrays. Utilizing the prior knowledge learned from the drug panel, we propose a statistical classification (dry-lab). According to the wet-lab for the complex of amiloride and insulin degrading enzyme, and the complex of amiloride and neutral endopeptidase, we are confident that this dry-lab is reliable. As the consequences of the dry-lab, we discover many interesting implications. Especially, we show that possible causes of Tacrine, donepezil, galantamine and huperzine A cannot improve the level of ACh which is against to their original design purpose but they still prevent AD to be worse as Aβ deposition appeared. On the other hand, we recommend Miglitol and Atenolol as the safe and potent drugs to improve the level of ACh before Aβ deposition appearing. Moreover, some nutrients such as NADH and Vitamin E should be controlled because they may harm health if being used in wrong way and wrong time. Anyway, the insights shown in this study are valuable to be developed further.</p></div

Spatial changing of charged amino acids on HA epitopes in variants/vaccine strains.

<p>a. Charged amino acids of five epitopes on HA included, Epitope A labeled in blue (124, 133, 135, 142 and 145), B in red (155, 156, 158, 160, 189, 190, 193 and 197), C in green (50, 53, 275, 276, 278, 279, 307 and 310), D in yellow (172, 173, 201, 207, 208, 222, 225 and 246) and E in cyan (57, 62, 63, 75, 82, 83, 92 and 261)(a.i and a-ii). b. The charged amino acids on epitopes of variants/vaccine strains were labeled, acidic ones in red, basic ones in blue and both acid and basic ones in green. c. T₁₃₅K on Epitope A resulted in a decrease of NGT_133-135, labeled in blue (T₁₃₅K) and cyan and K₁₆₀T on Epitope B did in an increase of NYT_158-160, labeled in red (K₁₆₀T) and cyan. Other amino acids on epitopes adjacent to NGS were labeled in green.</p