The addition of surfactants can considerably impact the electrical characteristics of an interface, and the zeta potential measurement is the standard method for its characterization. In this ...article, a comprehensive study of the zeta potential of poly(methyl methacrylate) (PMMA) in contact with aqueous solutions containing an anionic, a cationic, or a zwitterionic surfactant at different pH and ionic strength values is conducted. Electrophoretic mobilities are inferred from electrophoretic light scattering measurements of the particulate PMMA. These values can be converted into zeta potentials using permittivity and viscosity measurements of the continuous phase. Different behaviors are observed for each surfactant type, which can be explained with the various adsorption mechanisms on PMMA. For the anionic surfactant, the absolute zeta potential value below the critical micelle concentration (CMC) increases with the concentration, while it becomes rather constant around the CMC. At concentrations above the CMC, the absolute zeta potential increases again. We propose that hydrophobic-based adsorption and, at higher concentrations, the competing micellization process drive this behavior. The addition of cationic surfactant results in an isoelectric point below the CMC where the negative surface charge is neutralized by a layer of adsorbed cationic surfactant. At concentrations near the CMC, the positive zeta potential is rather constant. In this case, we propose that electrostatic interactions combined with hydrophobic adsorption are responsible for the observed behavior. The zeta potential in the presence of zwitterionic surfactant is influenced by the adsorption, because of hydrophobic interactions between the surfactant tail and the PMMA surface. However, there is less influence, compared to the ionic surfactants. For all three surfactant types, the zeta potential changes to more-negative or less-positive values for alkaline pH values, because of hydroxide adsorption. An increase of the ionic strength decreases the absolute value of the zeta potential, because of the shielding effects.
Chaetomiaceae comprises phenotypically diverse species, which impact biotechnology, the indoor environment and human health. Recent studies showed that most of the traditionally defined genera in ...Chaetomiaceae are highly polyphyletic. Many of these morphology-based genera, such as Chaetomium , Thielavia and Humicola , have been redefined using multigene phylogenetic analysis combined with morphology; however, a comprehensive taxonomic overview of the family is lacking. In addition, the phylogenetic relationship of thermophilic Chaetomiaceae species with non-thermophilic taxa in the family is largely unclear due to limited taxon sampling in previous studies. In this study, we provide an up-to-date overview on the taxonomy and phylogeny of genera and species belonging to Chaetomiaceae , including an extensive taxon sampling of thermophiles. A multigene phylogenetic analysis based on the ITS (internal transcribed spacers 1 and 2 including the 5.8S nrDNA), LSU (D1/D2 domains of the 28S nrDNA), rpb2 (partial RNA polymerase II second largest subunit gene) and tub2 (β-tubulin gene) sequences was performed on 345 strains representing Chaetomiaceae and 58 strains of other families in Sordariales . Divergence times based on the multi-gene phylogeny were estimated as aid to determine the genera in the family. Genera were delimited following the criteria that a genus must be a statistically well-supported monophyletic clade in both the multigene phylogeny and molecular dating analysis, fall within a divergence time of over 27 million years ago, and be supported by ecological preference or phenotypic traits. Based on the results of the phylogeny and molecular dating analyses, combined with morphological characters and temperature-growth characteristics, 50 genera and 275 species are accepted in Chaetomiaceae . Among them, six new genera, six new species, 45 new combinations and three new names are proposed. The results demonstrate that the thermophilic species fall into seven genera ( Melanocarpus , Mycothermus , Remersonia , Thermocarpiscus gen. nov. , Thermochaetoides gen. nov. , Thermothelomyces and Thermothielavioides ). These genera cluster in six separate lineages, suggesting that thermophiles independently evolved at least six times within the family. A list of accepted genera and species in Chaetomiaceae , together with information on their MycoBank numbers, living ex-type strains and GenBank accession numbers to ITS, LSU, rpb2 and tub2 sequences is provided. Furthermore, we provide suggestions how to describe and identify Chaetomiaceae species.
In 2007 a M7.7 earthquake occurred near the town of Tocopilla within the northern Chile seismic gap. Main shock slip, derived from coseismic surface deformation, was confined to the depth range ...between 30 and 55 km. We relocated ∼1100 events during six months before and one week after the main shock. Aftershock seismicity is first congruent to the main shock slip and then it spreads offshore west and northwest of Mejillones Peninsula (MP). Waveform modeling for 38 aftershocks reveals source mechanisms that are in the majority similar to the main shock. However, a few events appear to occur in the upper plate, some with extensional mechanisms. Juxtaposing the Tocopilla aftershocks with those following the neighboring 1995 Antofagasta earthquake produces a striking symmetry across an EW axis in the center of MP. Events seem to skirt around MP, probably due to a shallower Moho there. We suggest that the seismogenic coupling zone in northern Chile changes its frictional behavior in the downdip direction from unstable to mostly conditionally stable. For both earthquake sequences, aftershocks agglomerate in the conditionally stable region, whereas maximum inter‐seismic slip deficit and co‐seismic slip occurs in the unstable region. The boundary between the unstable and conditionally stable zones parallels the coastline. We identify a similar segmentation for other earthquakes in Chile and Peru, where the offshore segments break in great M > 8 earthquakes, and the onshore segments in smaller M < 8 earthquakes. Using critical taper analysis, we demonstrate a causal relationship between varying slip behavior on the interface and forearc wedge anatomy that can be attributed to spatial variations in the rate‐dependency of friction.
Key Points
Detailed analysis of slip and aftershocks of Tocopilla earthquake
Seismogenic zone is segmented in offshore locked and onshore transition zone
Forearc wedge architecture is reflecting varying frictional behavior
Achieving a fast, unidirectional flow of single-file water molecules (UFSWM) across nanochannels is important for membrane-based water purification or seawater desalination. For this purpose, ...electro-osmosis methods are recognized as a very promising approach and have been extensively discussed in the literature. Utilizing molecular dynamics simulations, here we propose a design for pumping water molecules in a single-walled carbon nanotube in the presence of a linearly gradient electric (GE) field. Such a GE field is inspired by GE fields generated from charged ions located adjacent to biological membrane water nanochannels that can conduct water in and out of cells and can be experimentally achieved by using the charged tip of an atomic force microscope. As a result, the maximum speed of the UFSWM can be 1 or 2 orders of magnitude larger than that in a uniform electric (UE) field. Also, inverse transportation of water molecules does not exist in case of the GE field but can appear for the UE field. Thus, the GE field yields a much more efficient UFSWM than the UE field. The giant pumping ability as revealed is attributed to the nonzero net electrostatic force acting on each water molecule confined in the nanotube. These observations have significance for the design of nanoscale devices for readily achieving controllable UFSWM at high speed.
The influence of various chamber geometries on shock wave reflections near the head end of rotating detonation engines was investigated. A hydrogen/air one-step chemical reaction model was used. The ...results demonstrated that the variation in flow field along the radial direction was not obvious when the chamber width was small, but became progressively more obvious as the chamber width increased. The thrust increased linearly, and the detonation height and the fuel-based gross specific impulse were almost constant as the chamber width increased. Near the head end, shock waves reflected repeatedly between the inner and outer walls. Both regular and Mach reflections were found near the head end. The length of the Mach stem increased as the chamber length increased. When the chamber width, chamber length and injection parameters were the same, the larger inner radius resulted in more shock wave reflections between the inner and outer walls. The greater the ratio of the chamber width to the inner radius, the weaker the shock wave reflection near the head end. The detonation height on the outer wall and the thrust, both increased correspondingly, while the specific impulse was almost constant as the inner radius of the chamber increased. The numerical shock wave reflection phenomena coincided qualitatively with the experimental results.
The adaptive control of sunlight through photochromic smart windows could have a huge impact on the energy efficiency and daylight comfort in buildings. However, the fabrication of inorganic ...nanoparticle and polymer composite photochromic films with a high contrast ratio and high transparency/low haze remains a challenge. Here, a solution method is presented for the in situ growth of copper‐doped tungsten trioxide nanoparticles in polymethyl methacrylate, which allows a low‐cost preparation of photochromic films with a high luminous transparency (luminous transmittance Tlum = 91%) and scalability (30 × 350 cm2). High modulation of visible light (ΔTlum = 73%) and solar heat (modulation of solar transmittance ΔTsol = 73%, modulation of solar heat gain coefficient ΔSHGC = 0.5) of the film improves the indoor daylight comfort and energy efficiency. Simulation results show that low‐e windows with the photochromic film applied can greatly enhance the energy efficiency and daylight comfort. This photochromic film presents an attractive strategy for achieving more energy‐efficient buildings and carbon neutrality to combat global climate change.
A photochromic (PC) film that simultaneously regulates solar heat and visible light entrance is introduced. On a sunny day, the film tints and blocks sunlight, which reduces energy consumption for cooling and preventing excessive brightness and glare. With weak sunlight intensity, the photochromic film becomes transparent to let sunlight enter the room, which prevents additional heating and lighting energy use.
Summary
Background
Clearance of hepatitis B surface antigen (HBsAg) indicates clinical control of hepatitis B virus (HBV) infection. However, little is known about the impact of viral genomic ...variations on HBsAg loss.
Methods
We explored the association between viral genomic factors and HBsAg loss in 2121HBeAg‐negative patients. HBV pre‐core stop codon (1896) and basal core promoter (BCP) (1762/1764) sequences were determined in patients with HBV DNA ≥200 IU/mL (N = 1693). The effect of HBV genotype on HBsAg loss was further validated in the whole cohort of 3445 HBsAg carriers.
Results
The cumulative lifetime (age 28–75 years) incidence of HBsAg loss was 50.4% in 2121 HBeAg‐negative patients. We found that genotype C, but not pre‐core stop codon or BCP mutants, was associated with HBsAg loss. Compared to genotype B patients, genotype C patients had higher lifetime chance of HBsAg loss, with hazard ratio of 1.8 (95% confidence interval: 1.4–2.4). Multivariable analysis showed that male sex, elevated ALT levels, lower serum HBV DNA and HBsAg levels, and genotype C infection were associated with higher chance of HBsAg loss independently. We then performed sensitivity analysis, which re‐included HBeAg‐positive, cirrhotic and treatment‐experienced patients, and confirmed the robustness of our results in 3445 HBsAg carriers.
Conclusion
Genotype C infection, compared to genotype B, is associated with a higher lifetime chance of HBsAg loss in Asian HBV carriers.
Wrought Mg alloy, WE43, is normally artificially aged after hot working (T5 temper). A solutionizing heat treatment is revealed to weaken the initial basal texture of the hot-rolled plate, which ...resulted in a reduction of the yield strength anisotropy (by notably lowering the in-plane strength). Solutionizing followed by peak aging (T6 temper) only leads to a marginal increase in hardness. The precipitate size and volume fraction are slightly greater for T6 as compared to T5. Different strategies to increase the number density of the precipitates were explored. T8 treatments (where the solutionized material is cold-deformed prior to aging) were carried out, and although the aging kinetics improved, the peak hardness did not. Similarly, two-step aging (first at 140°C for 4h, followed by 210°C) treatment provided no measurable increase in hardness. The T6 samples showed large grain boundary precipitates and a larger precipitate free zone, as compared to T5, which resulted in extensive intergranular ductile fracture, and reduced ductility. Finally, the lower ductility along the plate normal direction is related to stringers of Y-rich cuboidal dispersoids. The results reveal the incumbent T5 temper to be an optimum in terms of strength, ductility, and energy consumption.
Vertical rolling has been widely applied to control slab widths in hot plate rolling plants. In this research, due to the high ratio of width/thickness of the slab in vertical rolling, a symmetric ...cubic function model is established to depict the three-dimensional dog bone shape of the slab. The three-dimensional kinematically admissible velocity and strain rate fields are innovatively established based on the dual-stream function (DSF) method and the boundary conditions. According to the first variational principle of rigid-plastic, the numerical results of the force and shape parameters are obtained. To decrease the computation load and time, the Geometrical Approximation (GA) yield criterion, the Pavlov projection principle, and the mean value theorem are utilized to calculate the plastic deformation, shear, and friction power terms separately, and the analytical results of the slab shape and rolling force are received later. To certify the effectiveness of the submitted model, the computed slab shapes are compared with the results of other models and the rolling forces are compared with the measurements in a plate plant. Good agreement is found. Furthermore, the effects of key rolling process parameters, such as width reduction, thickness, and vertical roll radius, on the slab shape and stress state are illustrated. The variation mechanisms of the force and shape parameters are used to process parameters setting and adjusting.
Leukaemogenic mutations commonly disrupt cellular differentiation and/or enhance proliferation, thus perturbing the regulatory programs that control self-renewal and differentiation of stem and ...progenitor cells. Translocations involving the Mll1 (Kmt2a) gene generate powerful oncogenic fusion proteins, predominantly affecting infant and paediatric AML and ALL patients. The early stages of leukaemogenic transformation are typically inaccessible from human patients and conventional mouse models. Here, we take advantage of cells conditionally blocked at the multipotent haematopoietic progenitor stage to develop a MLL-r model capturing early cellular and molecular consequences of MLL-ENL expression based on a clear clonal relationship between parental and leukaemic cells. Through a combination of scRNA-seq, ATAC-seq and genome-scale CRISPR-Cas9 screening, we identify pathways and genes likely to drive the early phases of leukaemogenesis. Finally, we demonstrate the broad utility of using matched parental and transformed cells for small molecule inhibitor studies by validating both previously known and other potential therapeutic targets.