OBJECTIVE:The objective of this study is to propose a method for assessing the antiwear-ability (AW) or surface scratch-resistance (SR) efficacy of makeup products through in vitro experiments. MATERIALS AND METHOD:The method primarily involves measuring the change in weight as a means of evaluating the overall effectiveness. AW/SR effects are evaluated by applying a fixed amount of makeup product on artificial fake skin and comparing the weight difference after simulated friction/scratch. RESULTS:The in vitro results indicate that this method is easy to operate and yields repeatable data. It consistently reflects differences between samples when compared to clinical studies. CONCLUSIONS:This method effectively compares the AW/SR effects of makeup products and demonstrates utility in evaluating product efficacy and difference. It holds great scientific and practical value.

The coronavirus disease 2019 (COVID-19) is still causing a wide range of infections and deaths due to the high variability of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Therefore, it is necessary to establish a reliable and convenient pseudovirus-based neutralization assay to develop drug targeted variants of SARS-CoV-2. Based on the HIV-1 backbone, we generated a high titer luciferase (Luc)-expressing pseudovirus packaging system. Three dominant S mutant substitution pseudovirus were also established and identified compared to wide type in hACE2-overexpressing HEK-293T cells (293T-ACE2 cells). Compared to serine protease inhibitor camostat mesylate, the cysteine protease inhibitor E-64d could significantly block all SARS-CoV-2 mutant S pseudovirus infection in 293T-ACE2 cells. Furthermore, the neutralization ability of two antibodies targeted receptor-binding domain (RBD) of SARS-CoV-2 spike protein (S) was evaluated, which showed different inhibition dose-effect curves among four types of S pseudovirus. Overall, we developed a pseudovirus-based neutralization assay for SARS-CoV-2, which would be readily adapted to SARS-CoV-2 variants for evaluating antibodies.

Stimuli-responsive emulsions have attracted much attention in diverse fields. However, research on the rapid and effective demulsification based on pH-responsive emulsions has barely been reported, although they are viewed as promising canditates for oil-water separation processes after oil recovery. In the present work, we have successfully synthesized a series of pH-responsive emulsions on the basis of a novel polymer containing amphiphilic and protonated moieties. The properties of these pH-responsive emulsions including stability, morphology microscopy, Zeta potential, and interfacial tension have been extensively investigated. We observed that the prepared oil-in-water emulsion could stay stable for more than 24 h within the pH range of 8-10, while it lost 80-90% of the water in 10-20 min if the pH was adjusted to 2-4. The variation in emulsion stability can be attributed to the protonation of poly [2-(N, N-diethylamino) ethyl methacrylate] (PDEA) residues at low pH values. Accordingly the polymers intend to become more hydrophilic and depart from the oil-water interface, leading to an increased interfacial tension. Furthermore, it was found that the applied polymers aggregated at the oil-water interface and that the morphology of aggregations was strongly affected by the pH values. These proposed polymers enabled the formation of emulsion with a controllable response to the pH stimuli. This work is expected to shed light on the development of stimuli-responsive emulsions and may have significant implications in the fields of oil recovery, waste water treatment, and so forth. For example, due to the high w/o interface activity of surfactants such as heavy alkyl benzene sulfonate (HABS) and petroleum sulfonate, severe emulsion has also been found with the alkali-surfactant-polymer (ASP) produced fluid. Currently, rapid breaking of these emulsion fluid is still a big challenge.

Two kinds of olfactory substances, i.e. dimethyl isocamphthenol (2－MIB) and GSM in water sources and drinking water have been determined by the liquid－liquid extraction combined with gas chromatography－mass spec-trometry process, the cell walls in water bodies broken, and the intracellular and extracellular olfactory substances detected. 2－MIB and GSM have been subject to the addition of sodium chloride, normal hexane liquid－liquid extra-ction, concentration, and sample introduction, analyses and determination by gas chromatography－mass spectrometry process, and the selection of ion mode quantity. The results show that the method has good separation effect. The lin-earity of both 2－MIB and GSM is good in the standard curve of 10－100 μg/L. The regression coefficient R2 is more than 0.995. When the sampling volume is 1 000 mL,the detection limits are 2.58 ng/L and 2.45 ng/L,respectively. The standard recovery rate of 2－MIB and GSM are 86.7%－103.0%,and 87.5%－91.8%,respectively. The RSD of 2－MIB and GSM are 3.8%－7.9% and 4.1%－9.8%,respectively.

Recently, Lemoine and colleagues1 presented a novel marker of liver fibrosis, the gamma-glutamyl transpeptidase to platelet ratio (GPR), as a more accurate non-invasive marker than either the aspartate aminotransferase to platelet ratio index (APRI) or the fibrosis index based on four factors (FIB-4) for diagnosing liver fibrosis in patients with chronic hepatitis B virus (HBV) infection in West Africa, and a simple and inexpensive alternative to transient elastography and liver biopsy. Boyd and colleagues2 demonstrated good results for GPR in the diagnosis of liver fibrosis in patients with HBV/HIV co-infection in France. However, Stockdale and colleagues3 reported that in patients with HBV / human immunodeficiency virus (HIV) co-infection in West Africa, GPR showed poor correlation with transient elastography. Lemoine and colleagues4 subsequently responded that the diagnostic accuracy of GPR differed when using liver biopsy or transient elastography as the reference. These inconsistent opinions indicated that the value of GPR for diagnosing liver fibrosis was still uncertain and needed further validation, not to mention its value for dynamic assessment of treatment response in patients with chronic HBV infection. To further evaluate the accuracy of GPR for diagnosing liver fibrosis, we undertook a retrospective study in China of 1168 patients, with …

A pH and salt dually responsive emulsion has been designed on the basis of a novel amphiphilic macromolecule. It was found that the water separation of an oil-in-water emulsion reached up to ∼60% after standing for 10 min at low pH. 2-(Diethylamino)ethyl methacrylate (DEA) residues were found to induce the macromolecules to protonate and to be hydrophilic at pH values between 2 and 6, resulting in dewetting from oil droplet surfaces in water. Besides, the macromolecules form aggregates with different structures at the water/oil interface, depending on the pH value or salt concentration of the emulsion system, enabling the system to be demulsified in response to the pH or salt stimulus. The experimental results also showed that with the addition of aluminium chloride at 100 mg L-1, the water separation was about 70% after 20 min. A possible mechanism with respect to demulsifying was proposed on the basis of an "ion bridge" among sodium acrylate (SA) residues, inducing the macromolecules to "cross-link" and become insoluble, and leading to oil/water separation. Furthermore, at a fixed pH of 5, addition of salt to the aqueous dispersion increased the degree of oil-water interfacial activity and batch emulsions were significantly unstable to coalesce at a low salinity of 25-50 mg L-1. This finding presents a new manipulation on emulsion stability and potential applications in the fields of oil recovery, wastewater treatment, sludge removal, and so on.

The presence of thin aqueous films and their stability have a profound effect on the interactions between oil/brine/rock interfaces. In a previous report, we proposed that hydration forces, originating from the overlap of hydrated layers of different surfaces in the presence of sodium chloride, played an important role at short range. In the present work, divalent ions were introduced to the liquid films and, the mechanisms in improving oil recovery from low-salinity brine and the low-salinity effect at the molecular level were revealed. Through a direct force-measuring technique of chemical force microscopy (CFM), the functionalized atomic force microscopy (AFM) tips felt a solid surface to mimic the oil/rock interactions in brine. It was found that not only did the van der Waals and electrostatic forces have a great effect on this process due to the interactions between the charged interfaces of oil/water and water/solid, but also some important additional interactions appeared at short range under a variety of salinity concentrations or compositions. Taking into account the important role of structural forces under a small distance, the force profiles were fitted well with the theory of extended Derjaguin-Landau-Verwey-Overbeek (denoted by EDLVO) through a double-exponential or Gaussian model. Interestingly, low adhesion appeared in the presence of sodium sulfate, because hydration forces contributed to the resultant force depending on the intrinsic properties of the solvent or solute molecules, while in the presence of calcium chloride, high adhesion emerged due to the dispersion interaction between water and hydrocarbon molecules, as well as the reorientation or restructuring of water molecules with tiny breakage of hydrogen bonds. Therefore, on the basis of the EDLVO theory, additional forces were suggested to play an important part in short range, proposing a better understanding of the effect of divalent ions on the thin liquid films in the process of increasing oil recovery.

The adsorption process of a geminized amphiphilic polyelectrolyte, comprising double elementary charges and double hydrophobic tails in each repeat unit (denoted as PAGC8), was investigated and characterized by means of quartz crystal microbalance with dissipation (QCM-D), ellipsometry, and atomic force microscopy (AFM). By comparison, the self-assembly behaviors of a traditional polyelectrolyte without hydrophobic chains (denoted as PASC1) and an amphiphilic polyelectrolyte with a single hydrophilic headgroup and hydrophobic tail in each repeat unit (denoted as PASC8) at the solid/liquid interface were also investigated in parallel. A two-regime buildup was found in both amphiphilic systems of PASC8 and PAGC8, where the first regime was dependent on electrostatic interactions between polyelectrolytes and oppositely charged substrates, and the rearrangements of the preadsorbed chains and their aggregation behaviors on surface dominated the second regime. Furthermore, it was found that the adsorbed amount and conformation changed as a function of the charge density and bulk concentrations of the polyelectrolytes. The comparison of the adsorbed mass obtained from QCM-D and ellipsometry allowed calculating the coupling water content which reached high values and indicated a flexible aggregate conformation in the presence of PAGC8, resulting in controlling the suspension stability even at an extremely low concentration. In order to provide an insight into the mechanism of the suspension stability of colloidal dispersions, we gave a further explanation with respect to the interactions between surfaces in the presence of the geminized polyelectrolyte.