Systematic research on the effect of both positive and negative mismatch dopants in double-doped YBCO superconducting films

We report a novel doping strategy for YBa₂Cu₃O_7-x (YBCO) superconducting films by using a positive mismatch, Ba₂YNbO₆ (BYNO), and a negative mismatch, LaAlO₃ (LAO), simultaneously. Double doping can significantly reduce the c-strain in the YBCO film by canceling the strain between the two dopants. By systematically optimizing the doping amount of both BYNO and LAO, it was found that BYNO and LAO do not act equally. The microstructure and distribution of both BYNO and LAO were investigated with magneto-optic microscopy and scanning electron microscopy. The effect of BYNO and LAO on pinning was confirmed. The results of this study will help select appropriate positive mismatch and negative mismatch dopants, which is fundamental to the design and fabrication of pinning centers to fit different application scenarios.     

Active Components from Cassia abbreviata Prevent HIV-1 Entry by Distinct Mechanisms of Action

Cassia abbreviata is widely used in Sub-Saharan Africa for treating many diseases, including HIV-1 infection. We have recently described the chemical structures of 28 compounds isolated from an alcoholic crude extract of barks and roots of C. abbreviata, and showed that six bioactive compounds inhibit HIV-1 infection. In the present study, we demonstrate that the six compounds block HIV-1 entry into cells: oleanolic acid, palmitic acid, taxifolin, piceatannol, guibourtinidol-(4α→8)-epiafzelechin, and a novel compound named as cassiabrevone. We report, for the first time, that guibourtinidol-(4α→8)-epiafzelechin and cassiabrevone inhibit HIV-1 entry (IC₅₀ of 42.47 µM and 30.96 µM, respectively), as well as that piceatannol interacts with cellular membranes. Piceatannol inhibits HIV-1 infection in a dual-chamber assay mimicking the female genital tract, as well as HSV infection, emphasizing its potential as a microbicide. Structure-activity relationships (SAR) showed that pharmacophoric groups of piceatannol are strictly required to inhibit HIV-1 entry. By a ligand-based in silico study, we speculated that piceatannol and norartocarpetin may have a very similar mechanism of action and efficacy because of the highly comparable pharmacophoric and 3D space, while guibourtinidol-(4α→8)-epiafzelechin and cassiabrevone may display a different mechanism. We finally show that cassiabrevone plays a major role of the crude extract of CA by blocking the binding activity of HIV-1 gp120 and CD4.     

BiFC Method Based on Intraorganellar Protein Crowding Detects Oleate-Dependent Peroxisomal Targeting of Pichia pastoris Malate Dehydrogenase

The maintenance of intracellular NAD⁺/NADH homeostasis across multiple, subcellular compartments requires the presence of NADH-shuttling proteins, which circumvent the lack of permeability of organelle membranes to these cofactors. Very little is known regarding these proteins in the methylotrophic yeast, Pichia pastoris. During the study of the subcellular locations of these shuttling proteins, which often have dual subcellular locations, it became necessary to develop new ways to detect the weak peroxisomal locations of some of these proteins. We have developed a novel variation of the traditional Bimolecular Fluorescence Complementation (BiFC), called divergent BiFC, to detect intraorganellar colocalization of two noninteracting proteins based on their proximity-based protein crowding within a small subcellular compartment, rather than on the traditional protein–protein interactions expected for BiFC. This method is used to demonstrate the partially peroxisomal location of one such P. pastoris NADH-shuttling protein, malate dehydrogenase B, only when cells are grown in oleate, but not when grown in methanol or glucose. We discuss the mode of NADH shuttling in P. pastoris and the physiological basis of the medium-dependent compartmentalization of PpMdhB.     

Micromorphological description of vernacular cob process and comparison with rammed earth

Past builders have developed very low-embodied energy construction techniques optimizing the use of local building materials. These techniques are a source of inspiration for modern sustainable building. Unfortunately, this know-how was orally transmitted and was lost as earth construction fell into disuse during the 20th century in European countries. The absence of written documents makes necessary to use an archaeological approach in order to rediscover these construction strategies. Micromorphological analysis of thin sections collected in earth building walls was used for the first time to describe cob construction technique and highlighted several typical pedofeatures allowing to clearly identifying this process. Finally, a first comparison of the cob and rammed earth micromorphological features permitted to identify two key factors to distinguish these two techniques, the manufacturing state (solid or plastic) and the organization of the material in the wall.     

Preparation and mechanism analysis of morphology-controlled cellulose nanocrystals via compound enzymatic hydrolysis of eucalyptus pulp

First, making from eucalyptus cellulose fiber, the influences of different compound enzymolysis conditions on the morphology of cellulose nanocrystals (CNCs) were studied. Under the actions of the compound enzyme composed of cellulase and xylanase with the concentration ratio of 9:1, total enzyme concentrations of 10 and 500 U mL⁻¹ and the hydrolysis time of 12 and 5 h, the rod-like CNCs (length 600 nm, width 30 nm) and the spherical CNCs (40 nm) were obtained, respectively. Subsequently, the crystallinities, chemical structures, and thermal stabilities of the rod-like and spherical CNCs revealed that, the CNCs structures were still similar to those of the eucalyptus cellulose fiber, the thermal decomposition temperatures of the rod-like and spherical CNCs (345, 343 °C) were a little lower than that of the eucalyptus cellulose fiber (364 °C). Lastly, the control mechanism of CNC morphology by the compound enzymatic hydrolysis was also discussed. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48407.     

Aerobic Biodegradation of Acetylated Starch

Some acetylated starch samples with degrees of substitution varying from 0.03 to 1.6 are submitted to aerobic degradation by Bacillus amyloliquefaciens. The degradation is expressed by the concentration of reducing sugars evolved from the substrate, by the amylolytic activity and by the assessment of the CO₂ release resulting from the mineralization of the acetylated starch. With formation of exclusively glucose and maltose as control substrates, the hydrolysis is complete. For the samples with a low acetylation degree, the hydrolysis is slowed down as a result of inhibition by the acetyl groups. When the degree of acetylation is high, it becomes necessary to add inducers of acetylesterase activity. So, for acetylated starch with a degree of substitution of 1.6, the mineralization percentage increases up to 30% upon addition of isopropyl-β-D -thiogalactopyranoside.