Regeneration mechanism of a novel high-performance biochar mercury adsorbent directionally modified by multimetal multilayer loading.

Biochar that is directly obtained by pyrolysis exhibits a low adsorption efficiency; furthermore, the process of recycling adsorbents is ineffective. To solve these problems, conventional chemical coprecipitation, sol-gel, multimetal multilayer loading and biomass pyrolysis coking processes have been integrated. After selecting specific components for structural design, a novel high-performance biochar adsorbent was obtained. The effects of the O2 concentration and temperature on the regeneration characteristics were explored. An isothermal regeneration method to repair the deactivated adsorbent in a specific atmosphere was proposed, and the optimal regeneration mode and conditions were determined. The microscopic characteristics of the regenerated samples were revealed along with the mechanism of Hg0 removal and regeneration by using temperature-programmed desorption technology and adsorption kinetics. The results show that doping multiple metals can reduce the pyrolysis reaction barrier of the modified biomass. On the modified surface of the sample, the doped metals formed aggregated oxides, and the resulting synergistic effect enhanced the oxidative activity of the biochar carriers and the threshold effect of Ce oxide. The optimal regeneration conditions (5% O2 and 600 °C) effectively coordinated the competitive relationship between the deep carbonization process and the adsorption/oxidation site repair process; in addition, these conditions provided outstanding structure-effect connections between the physico-chemical properties and Hg0 removal efficiency of the regenerated samples. Hg0 adsorption by the regenerated samples is a multilayer mass transfer process that involves the coupling of physical and chemical effects, and the surface adsorption sites play a leading role.

Study on the Hg0 removal characteristics and synergistic mechanism of iron-based modified biochar doped with multiple metals.

An iron-based composite adsorbent with biochar as the support was prepared by coprecipitation and the sol-gel method. Both single-iron-based modified biochar without doping with other metals and iron-based modified biochar doped with multiple metals (Ce, Cu, Co, Mn) were synthesised. The adsorption kinetics were analysed, and temperature-programmed desorption measurements were performed to reveal the inherent difference in mechanism between the oxidation and adsorption of Hg0 by the modified biochar and to elucidate the key mechanism of Hg0 removal. The results show that the removal of Hg0 by the modified biochar mainly includes adsorption and oxidation processes. The adsorption process is divided into two stages, external and internal mass transfer, both of which occur via multilayer adsorption. HgO and Hg-OM are the main forms of Hg0 present on the modified biochar surface. Doped metal oxides can play a synergistic role in enhancing the mercury removal performance of the modified biochar.

Cell death induced by α-terthienyl via reactive oxygen species-mediated mitochondrial dysfunction and oxidative stress in the midgut of Aedes aegypti larvae.

α-Terthienyl (α-T) is a photosensitizer that produces many reactive oxygen species (ROS) under ultraviolet light. Here, we aimed to evaluate the oxidation mechanism of the 25%, 50%, and 75% lethal concentrations in Aedes aegypti larvae; the lethal concentration of α-T was used as the test value. The effects on mitochondria, oxidative stress, and cell death patterns caused by ROS were evaluated. The results showed that α-T mainly produced large amounts of ROS in the midgut of larvae. Moreover, mitochondrial ROS were increased in midgut cells, and the production of ROS sites, such as complex enzymes, was inhibited, resulting in enhanced production of ROS. Ultrastructural analysis of mitochondria revealed significant vacuolation, decreased activity of tricarboxylic acid cycle enzymes, and reduced ATP content and mitochondrial membrane potential in the high concentration group compared with those in the control group. Additionally, mitochondrial biosynthesis was blocked in the high concentration group. Thus, exposure to α-T disrupted mitochondrial function, although the mitochondrial DNA content may have increased because of mitochondrial self-protection mechanisms against oxidative stress. Furthermore, high concentrations of α-T aggravated oxidative stress and increased the number of intracellular oxidative damage products. Reverse transcription polymerase chain reaction and fluorescence staining showed that ROS induced by low α-T concentrations upregulated apoptotic genes, including Dronc (P < 0.05), thereby promoting apoptosis. Moderate concentrations of α-T promoted autophagy through induction of ROS, inhibited apoptosis, and induced necrosis. In contrast, high α-T concentrations induced high levels of ROS, which caused mitochondrial dysfunction and increased cytoplasmic Ca2+ concentration, directly inducing cell necrosis. We also found that α-T may disrupt the permeability of the peritrophic membrane, leading to intestinal barrier dysfunction. These results provided insights into the mode of action of α-T in Aedes aegypti.

Bioactive spirans and other constituents from the leaves of Cannabis sativa f. sativa.

In this paper, 17 compounds (1-17) were isolated from the leaves of Hemp (Cannabis sativa f. sativa). Among the isolates, two were determined to be new spirans: cannabispirketal (1), and α-cannabispiranol 4'-O-ß-D-glucopyranose (2) by 1D and 2D NMR spectroscopy, LC-MS, and HRESIMS. The known compounds 7, 8, 10, 13, 15, and 16 were isolated from Hemp (C. sativa f. sativa) for the first time. Furthermore, compounds 8 and 13 were isolated from the nature for the first time. All isolated compounds were evaluated for cytotoxicity on different tissue-derived passage cancer cell lines through cell viability and apoptosis assay. Among these compounds, compounds 5, 9 and 16 exhibited a broad-spectrum antitumor effect via inhibiting cell proliferation and promoting apoptosis. These results obtained have provided valuable clues to the understanding of the cytotoxic profile for these isolated compounds from Hemp (C. sativa f. sativa).

[Transportation and risk assessment of heavy metal pollution in water-soil from the Riparian Zone of Daye Lake, China].

Each 20 water samples and soil samples (0-10 cm, 10-20 cm) were collected from the riparian zone of Daye Lake in dry season during March 2013. Heavy metals (Cu, Ph, Cd, Zn) have been detected by flame atomic absorption spectrometric (FAAS). The results showed that the average concentrations of Cu, Pb, Cd, Zn in the water were 7.14, 25.94, 15.72 and 37.58 microg x L(-1), respectively. The concentration of Cu was higher than the five degree of the surface water environment quality standard. The average concentrations of Cu, Pb, Cd, Zn in soil(0-10 cm) were 108.38, 53.92, 3.55, 139.26 mg x kg(-1) in soil (10-20 cm) were 93.00, 51.72, 2.08, 171.00 mg x kg(-1), respectively. The Cd concentrations were higher than the three grade value of the national soil environment quality standard. The transportation of Pb from soil to water was relatively stable, and Zn was greatly influenced by soil property and the surrounding environment from soil to water. The transformation of heavy metal in west riparian zone was higher than that of east riparian zone. The potential environmental risk was relatively high. Cu, Pb, Cd, Zn were dominated by residue fraction of the modified BCR sequential extraction method. The overall migration order of heavy metal element was: Pb > Cu > Cd > Zn. There were stronger transformation and higher environmental pollution risk of Cu, Pb. The index of assessment and potential ecological risk coefficient indicated that heavy metal pollution in soil (0-10 cm) was higher than the soil (10-20 cm), Cd was particularly serious.

The investigation of glucose metabolism and insulin secretion in subjects of chronic hepatitis B with cirrhosis.

AIMS: To investigate the situations of abnormal glucose metabolism and dysfunction of pancreatic islet beta cells in subjects of chronic hepatitis B (CHB) with cirrhosis. METHODS: 106 hepatitis B virus (HBV) positive subjects with liver cirrhosis as well as with different grade of Child-Pugh and 37 healthy subjects were included in this study. The oral glucose tolerance test (OGTT), C-peptide and insulin release test were detected. Plasma glucose and insulin levels were analyzed periodically for 2 h after oral glucose loading. RESULTS: There was no significant difference in the level of fasting plasma glucose and C-peptide between cirrhosis group and control group (P>0.05). The levels of OGTT 2 h glucose, insulin and C peptide were significantly higher in cirrhosis group than control group (P<0.01). Peak plasma glucose levels were obtained at 60 min in normal group and cirrhosis group. The peak insulin and C-peptide response occurred at 60 min in normal group, whereas it was delayed to 120 min in cirrhosis group. There was a significant difference between two groups in the pattern of plasma glucose levels at corresponding time points (P<0.05). The OGTT 2 h glucose and insulin levels were positively correlated with Child-Pugh Score (r1 = 0.389, r2 = 0.508, P<0.01). CONCLUSION: These findings implied that there was a certain degree of insulin resistance and abnormal glucose metabolism in the patients with liver cirrhosis.

Optimization of effect factors for mycelial growth and exopolysaccharide production by Schizophyllum commune.

This paper is concerned with the optimization of effect factors for mycelial growth and exopolysaccharide production by Schizophyllum commune by one-factor-at-a-time and orthogonal methods. The one-factor-at-a-time method was adopted to investigate the effects of six different compounds (sodium carboxymethylcellulose, L: -glutamic acid, V(B1), naphthalene acetic acid, oleic acid, and Tween 80) on mycelial growth and exopolysaccharide production. Among these factors, oleic acid, V(B1) and Tween 80 were identified to be the most important factors. Subsequently, the concentration of oleic acid, V(B1) and Tween 80 were optimized using the orthogonal matrix method. The effects of the factors on the mycelial growth of S. commune were in the order of oleic acid > V(B1) > Tween 80, and those on exopolysaccharide production were in the same order. The optimal concentration for mycelia and exopolysaccharide were determined as oleic acid 0.1% (v/v), V(B1) 0.5 mg/L, and Tween 80 6 mg/L. The subsequent verification experiments confirmed the validity of the models. Under this optimized conditions in shake flask culture, the mycelial yield and exo-biopolymer production were 25.93 and 2.79 g/L, respectively, which were considerably higher than those obtained in the preliminary studies. The result was further confirmed in a 7-L fermentor experiments.

Nano-TiO2 induced secondary structural transition of silk fibroin studied by two-dimensional Fourier-transform infrared correlation spectroscopy and Raman spectroscopy.

By sol-gel processing, regenerated nano-TiO2/SF (silk fibroin) composite films were synthesized. The experimental results revealed that the nano-TiO2 particles were well dispersed in the regenerated silk fibroin. Using FT-IR and Raman spectroscopy, the secondary structures of these composite films with concentrations of 0, 0.2, 0.4, 0.8 and 1.6 wt% were characterized. Concentration-perturbed two-dimensional (2D) correlation spectra were calculated for the spectra in the 1800-1600 cm(-1) region. To investigate nano-TiO2 particles induced changes in the secondary structure and hydration, the slice spectra were calculated from the synchronous and asynchronous spectra, respectively. The transmittance IR and Raman spectra measurement indicated that the secondary structure of the pure silk film was mostly random coil and alpha-helix, while the composite films were beta-sheet. With increasing nano-TiO2 content, the secondary structure of composite films was changed from typical Silk I to typical Silk II. However, it was found that the transition of the SF's secondary structures would be restrained by excessive nano-TiO2 (over 0.8%) introduced into the composite SF films. Through the FT-IR absorbance and 2D correlation spectra, it was demonstrated that the formation of nano-TiO2 particles could induce the partial transformation of SF conformation from Silk I to Silk II.