Impact of H2O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses.

Lollingite (FeAs2) is considered an arsenic-bearing mineral that is oxidized faster than arsenopyrite. The geometric configuration, chemical valence bond, and microscopic reaction of the oxidation on the surface of lollingite were systematically studied, which are of great significance for understanding the mechanism of oxidative dissolution. X-ray photoelectron spectroscopy (XPS) measurements and density functional theory (DFT) calculations were carried out to characterize the (101) surface oxidation process of lollingite under the O2/O2 + H2O conditions. XPS results confirmed that the participation of water molecules can promote the formation of abundant OH structures on the surface of lollingite, while the relative concentration of O, As(III), and Fe(III) increased. Moreover, the DFT results demonstrated that the (101) As-terminal plane of FeAs2 was the most stable surface with the lowest surface energy. H2O molecules were physically adsorbed onto the Fe atoms of the lollingite surface, while oxygen molecules can readily be adsorbed on the Fe-As2 site by chemical adsorption processes. The oxidation process of the lollingite surface with water includes the following mechanisms: adsorption, dissociation, formation of the hydrogen bond, and desorption. The dissociation of the H2O molecule into OH and H led to the hydroxylation of both Fe and As atoms and the formation of hydrogen bonding. The participation of H2O molecules can also reduce the reaction energy barrier and accelerate the oxidation reaction of the lollingite surface, especially as far as the water dissociation and formation of hydrogen bonds are concerned. According to PDOS data, there is considerable hybridization between the d orbitals of bonded Fe atoms and the p orbitals of O atoms, as well as between the p orbitals of bonded As atoms and the p orbitals of O atoms. Due to a strong propensity for orbital hybridization and bonding between the s orbitals of the H atoms in H2O molecules and the p orbitals of the O atoms on the (101) surface, water molecules have the ability to speed up the oxidation on the surface.

Red mud-metakaolin based cementitious material for remediation of arsenic pollution: Stabilization mechanism and leaching behavior of arsenic in lollingite.

The proper treatment of lollingite is of great significance due to its rapid oxidation leading to release of arsenic into the environment. Herein, a green multi-solid waste geopolymer, consisting of red mud, metakaolin, blast furnace slag, and flue gas desulfurization gypsum, was developed. The obtained red mud-metakaolin-based (RMM) geopolymer demonstrated good arsenic retention capability. The results showed that the replacement of SO42- in ettringite with AsO42- via ion exchange, formation of Ca-As and Fe-As precipitates, and physical encapsulation with aluminosilicate gel were the main mechanisms that prevented the release of arsenic. Further dissolution of ettringite in RMM was alleviated by adding a suitable amount of Ca(OH)2 and controlling the pH of the leachate. TCLP results verified that RMM materials possessed an outstanding ability to stabilize arsenic, with a leaching rate below the permitted value of 5 mg/L for safe disposal. The low leachability of the RMM geopolymers (<0.50 mg/L) is potentially related to the pH buffering capacity of the hydration products at a pH range of 2-5. RMM geopolymers showed a high compressive strength (>15 MPa) and low arsenic leaching concentration (<2.66 mg/L) after 28 days of curing. These results demonstrate the potential of RMM geopolymers to be utilized as an environmentally friendly backfilling cementitious material for sustainable remediation of arsenic pollution.

Automatic Facial Recognition of Williams-Beuren Syndrome Based on Deep Convolutional Neural Networks.

Background: Williams-Beuren syndrome (WBS) is a rare genetic syndrome with a characteristic "elfin" facial gestalt. The "elfin" facial characteristics include a broad forehead, periorbital puffiness, flat nasal bridge, short upturned nose, wide mouth, thick lips, and pointed chin. Recently, deep convolutional neural networks (CNNs) have been successfully applied to facial recognition for diagnosing genetic syndromes. However, there is little research on WBS facial recognition using deep CNNs. Objective: The purpose of this study was to construct an automatic facial recognition model for WBS diagnosis based on deep CNNs. Methods: The study enrolled 104 WBS children, 91 cases with other genetic syndromes, and 145 healthy children. The photo dataset used only one frontal facial photo from each participant. Five face recognition frameworks for WBS were constructed by adopting the VGG-16, VGG-19, ResNet-18, ResNet-34, and MobileNet-V2 architectures, respectively. ImageNet transfer learning was used to avoid over-fitting. The classification performance of the facial recognition models was assessed by five-fold cross validation, and comparison with human experts was performed. Results: The five face recognition frameworks for WBS were constructed. The VGG-19 model achieved the best performance. The accuracy, precision, recall, F1 score, and area under curve (AUC) of the VGG-19 model were 92.7 ± 1.3%, 94.0 ± 5.6%, 81.7 ± 3.6%, 87.2 ± 2.0%, and 89.6 ± 1.3%, respectively. The highest accuracy, precision, recall, F1 score, and AUC of human experts were 82.1, 65.9, 85.6, 74.5, and 83.0%, respectively. The AUCs of each human expert were inferior to the AUCs of the VGG-16 (88.6 ± 3.5%), VGG-19 (89.6 ± 1.3%), ResNet-18 (83.6 ± 8.2%), and ResNet-34 (86.3 ± 4.9%) models. Conclusions: This study highlighted the possibility of using deep CNNs for diagnosing WBS in clinical practice. The facial recognition framework based on VGG-19 could play a prominent role in WBS diagnosis. Transfer learning technology can help to construct facial recognition models of genetic syndromes with small-scale datasets.

Induction of apoptosis by chelerythrine chloride through mitochondrial pathway and Bcl-2 family proteins in human hepatoma SMMC-7721 cell.

The objective of this study was to evaluate the antitumor activity of chelerythrine chloride (CHE) and investigate its potential apoptotic induction mechanism in SMMC-7721 cells. Our results suggested that the proliferation of SMMC-7721 cells was inhibited by CHE in a time and dose dependent manner, with a significant accumulation in S phase, and the cells exhibited typical apoptotic features. Moreover, CHE remarkably induced apoptosis by disruption of the mitochondrial membrane potential, release of Cyt-c, activation of caspase-3, and cleavage of poly-ADP-ribose polymerase in a dose dependent manner. Furthermore, the expression of Bcl-xl was downregulated while Bax and Bid expression was upregulated, and no variation was found for Bcl-2. These results indicated that CHE may play an important role in suppression of tumor growth by inducing apoptosis in human hepatoma cells via the activation of a mitochondrial pathway and regulating the expression of Bcl-2 family proteins.

Three new derivatives of anti-HIV-1 polyphenols isolated from Salvia yunnanensis.

During the study of anti-HIV-1 active components of the aqueous extracts of the roots of Salvia yunnanensis, three new derivatives of polyphenols, namely: methyl salvianolate A (2), ethyl salvianolate A (3) and cis-lithospermic acid (5) were isolated along with two known polyphenols, salvianolic acid A (1) and lithospermic acid (4) their structures were elucidated on the basis of NMR and MS spectral analyses. The anti-HIV-1 activities of the 5 polyphenols were tested for the inhibition of P24 antigen in HIV-1 infected MT-4 cell cultures and HIV-1 replicative enzymes in vitro.

A potent anti-HIV polyphenol from Salvia yunnanensis.

A new polyphenol, designated as salvianolic acid N, was isolated from the aqueous extracts of the roots of Salvia yunnanensis. Its chemical structure was elucidated as 3-(3,4-dihydroxylphenyl)-2-[(E)-3-(1,8,9-trihydroxyl-dibenzo[b,f]oxpin-3-yl)acryloxloxy]propanoic acid (1) on the basis of NMR and MS spectral analyses. The new polyphenol inhibited both HIV-1 IN in vitro and also reduced HIV-1 p24 antigen in MT-4 cell lines.

[Studies on polyphenolic chemical constitutents from root of Salvia yunnansis].

OBJECTIVE: To study the chemical constituents in the root of Salvia yunnansis. METHOD: Compounds were isolated and purified by Diaion HP20, Sephadex LH - 20, ODS chromatography. Their structures were determined by spectral analysis and chemical evidence. RESULT: Twelve compounds were isolated and identified from the root of S. yunnansis protocatechaldehyde (1), caffeic acid (2), ferulic acid (3), rosmarinic acid (4), salvianolic acid A (5), salvianolic acid C (6), lithospermicacid (7), lithospermicacid B (8), 9'-methyl lithospermate B (9), 9"'-methyl lithospermate B (10), 9',9'''-dimethyl lithospermate B (11), 9'-ethyl lithospermate B (12). CONCLUSION: The compounds 1, 2, 3, 5, 6, 9, 10, 11 and 12 were first isolated from S. yunnanensis.

[Studies on chemical constitutents in roots of Jasminum sambac].

OBJECTIVE: To isolate and identify the chemical constitutents in roots of Jasminum sambac. METHOD: The compounds were isolated by means of chromatography and the structures were identified on the basis of physical and spectral data. RESULT: Dotriacontanoic acid, dotriacontanol, oleanolic acid, daucosterol and hesperidin were elucidated. CONCLUSION: All compounds were found in this plant for the first time.