Polyelectrolyte multilayer films as backflushable nanofiltration membranes with tunable hydrophilicity and surface charge

A diverse set of supported polyelectrolyte multilayer (PEM) membranes with controllable surface charge, hydrophilicity, and permeability to water and salt was designed by choosing constituent polyelectrolytes and by adjusting conditions of their deposition. The membranes were characterized in terms of their water and MgSO4 permeabilities and resistance to colloidal fouling. The commercial nanofiltration membrane (NF270) was used as a comparative basis. Highly hydrophilic and charged PEMs could be designed. For all membranes, MgSO4 permeability coefficients of NF270 and all PEM membranes exhibited a power law dependence on concentration: Ps [is proportional to] C-[tau], 0.19 < [tau] < 0.83. PEM membranes were highly selective and capable of nearly complete intrinsic rejection of MgSO4 at sufficiently high fluxes. With the deposition of colloids onto the PEM surface, the separation properties of one type of polyelectrolyte membrane showed similar rejection and superior flux properties compared to NF270 membranes. We hypothesize that a PEM-colloid nanocomposite was formed as a result of colloidal fouling of these PEM films. The feasibility of regenerating the PEM membranes fouled by colloids was also demonstrated. In summary, the PEM-based approach to membrane preparation was shown to enable the design of membranes with the unique combination of desirable ion separation characteristics and regenerability of the separation layer

Vertebrate Paralogous MEF2 Genes: Origin, Conservation, and Evolution

BACKGROUND: The myocyte enhancer factor 2 (MEF2) gene family is broadly expressed during the development and maintenance of muscle cells. Although a great deal has been elucidated concerning MEF2 transcription factors' regulation of specific gene expression in diverse programs and adaptive responses, little is known about the origin and evolution of the four members of the MEF2 gene family in vertebrates. METHODOLOGY/PRINCIPAL FINDINGS: By phylogenetic analyses, we investigated the origin, conservation, and evolution of the four MEF2 genes. First, among the four MEF2 paralogous branches, MEF2B is clearly distant from the other three branches in vertebrates, mainly because it lacks the HJURP_C (Holliday junction recognition protein C-terminal) region. Second, three duplication events might have occurred to produce the four MEF2 paralogous genes and the latest duplication event occurred near the origin of vertebrates producing MEF2A and MEF2C. Third, the ratio (K(a)/K(s)) of non-synonymous to synonymous nucleotide substitution rates showed that MEF2B evolves faster than the other three MEF2 proteins despite purifying selection on all of the four MEF2 branches. Moreover, a pair model of M0 versus M3 showed that variable selection exists among MEF2 proteins, and branch-site analysis presented that sites 53 and 64 along the MEF2B branch are under positive selection. Finally, and interestingly, substitution rates showed that type II MADS genes (i.e., MEF2-like genes) evolve as slowly as type I MADS genes (i.e., SRF-like genes) in animals, which is inconsistent with the fact that type II MADS genes evolve much slower than type I MADS genes in plants. CONCLUSION: Our findings shed light on the relationship of MEF2A, B, C, and D with functional conservation and evolution in vertebrates. This study provides a rationale for future experimental design to investigate distinct but overlapping regulatory roles of the four MEF2 genes in various tissues

Electrochemistry and Spectroelectrochemistry of Sapphyrins, Open-chain Pentapyrroles, Cobalt Corroles and Cobalt Dipyrrin-bisphenols

For decades, pyrrolic complexes have attracted enormous scientific attention in various fields because of the potential applications in medicine and energy storage. In this thesis, about 31 pyrrolic compounds are studied, focusing on their spectroscopic and electrochemical properties along with characterizations by various other methods. The general introduction for the investigated pentapyrolic, tetrapyrrolic and dipyrolic complexes (Chapter 1), as well as the used experimental methods (Chapter 2), are given prior to the data and discussions. Firstly, the spectral properties, protonation reactions, and electrochemistry of open-chain pentapyrroles and sapphyrins with various meso-tetraaryl substituents are discussed (Chapter 3 and 4) along with the protonation-initiated conversion of pentapyrroles to sapphyrins upon oxidation. The second part (Chapters 5, 6 and 7) is dedicated to a series of studies on electrochemistry and spectroelectrochemistry for the cobalt corroles axially ligated with bis(pyridine), mono(DMSO) and bis(ammonia). The last part (Chapter 8) presents the ligand noninnocence in cobalt dipyrrin-bisphenols as to their electrochemistry and spectroscopic properties in nonaqueous media. The potentials for each electrode reaction for all investigated pyrrolic complexes were measured by cyclic voltammetry and the electron-transfer mechanisms evaluated by analysis of the electrochemical data combined with UV−visible spectra of the neutral, electroreduced, and electroxidized forms of the investigated pyrrolic compounds.Chemistry, Department o

A dataset of eye gaze images for calibration-free eye tracking augmented reality headset

Abstract Eye tracking is a widely used technique. To enhance eye gaze estimation in different contexts, many eye tracking datasets have been proposed. However, these datasets depend on calibrations in data capture and its applications. We seek to construct a dataset that enables the design of a calibration-free eye tracking device irrespective of users and scenes. To reach this goal, we present ARGaze, a dataset with 1,321,968 pairs of eye gaze images at 32 × 32 pixel resolution and 50 corresponding videos of world views based on a replicable augmented reality headset. The dataset was captured from 25 participants who completed eye gaze tasks for 30 min in both real-world and augmented reality scenes. To validate the dataset, we compared it against state-of-the-art eye gaze datasets in terms of effectiveness and accuracy and report that the ARGaze dataset achieved record low gaze estimation error by 3.70 degrees on average and 1.56 degrees on specific participants without calibrations to the two scenes. Implications for generalising the use of the dataset are discussed

Porphyrins as Photoredox Catalysts: Experimental and Theoretical Studies

Metalloporphyrins not only are vital in biological systems but also are valuable catalysts in organic synthesis. On the other hand, catalytic properties of free base porphyrins have been less explored. They are mostly known as efficient photosensitizers for the generation of singlet oxygen via photoinduced energy transfer processes, but under light irradiation, they can also participate in electron transfer processes. Indeed, we have found that free base tetraphenylporphyrin (H₂TPP) is an efficient photoredox catalyst for the reaction of aldehydes with diazo compounds leading to α-alkylated derivatives. The performance of a porphyrin catalyst can be optimized by tailoring various substituents at the periphery of the macrocycle at both the β and <i>meso</i> positions. This allows for the fine tuning of their optical and electrochemical properties and hence their catalytic activity

Ganmaidazao decoction alleviated cognitive impairment on Alzheimer's disease rats by regulating gut microbiota and their corresponding metabolites

Traditional Chinese medicine targeted at gut microbiota has good effects in relieving the clinical manifestation of Alzheimer's disease, and intestinal metabolites are considered as a bridge of communication between the brain-gut axis. In order to explore the molecular mechanism of Ganmaidazao decoction treatment, first, the model rats induced by Aβ25-35 and d-gal were used to test the therapy of Ganmaidazao extract using the Morris Water Maze, Western Blot and Elisa. Then the 16S rDNA gene sequencing of the gut microbiota as well as UPLC-QTOF/MS-based metabolomic analysis of feces were carried out. Last, the relationship between Alzheimer's disease, gut microbiota and metabolites was analyzed. Results showed that the abundance and diversity of gut microbiota were rescued and the changes of fecal metabolites in rats with Alzheimer's disease were reversed after Ganmaidazao decoction administration, which were mainly related to lipid metabolism, steroid hormone metabolism, energy metabolism, amino acid metabolism and bile acid metabolism. After associating with Spearman’s correlation analysis, we concluded that gut microbiota and metabolites were closely related and Ganmaidazao decoction could interfere with the balance of gut microbiota and their corresponding metabolites to exert anti- Alzheimer’s disease effect. Combined with PICRUSt2 functional prediction of gut microbiota and metabolomics results, phenylalanine metabolism has been focused as a key metabolic pathway, and Ganmaidazao decoction can reduce the abnormal accumulation of phenylalanine and phenylpyruvate and promote their metabolism by restoring the activity of phenylalanine hydroxylase. This integrated omics approach has potential roles in understanding the complex mechanisms of Ganmaidazao decoction in treating Alzheimer’s disease