Preparation of two zwitterionic polymer functionalized stationary phases and comparative evaluation under mixed-mode of reversed phase/ hydrophilic interaction/ion exchange chromatography.

Zwitterions are a promising choice to prepare separation materials because of their hydrophilicity and biocompatibility. We described the preparation of two zwitterionic polymer functionalized stationary phases and evaluation under mixed-mode chromatography. A zwitterionic monomer, S-(4-vinylbenzyl) cysteine (SVC), was synthesized and bonded to silica via reversible addition fragmentation chain transfer (RAFT) polymerization to afford a zwitterionic stationary phase, Sil-SVC. A hydrophobic monomer, N-(4-phenylbutan-2-yl) acrylamide (NPA), was copolymerized with SVC onto the stationary phase (Sil-SVCNPA) for comparison. The stationary phases were characterized with FT-IR, TGA, EA, and zeta-potential measurements. Mobile phase composition (ACN content, pH and salt concentration) was varied to study the retention property. Linear solvation energy relationship and Van't Hoff plot were used to investigate the retention mechanism and how chromatographic conditions influenced it. Both stationary phases showed a mixed-mode of RPLC/HILIC/IEC and satisfactory performance in separating hydrophobic analytes (alkylbenzenes and polycyclic aromatic hydrocarbons), hydrophilic nucleotide and bases, and anions, high column efficiency of 60,000 plates·m-1 was achieved. In summary, zwitterionic polymers are attractive options to prepare stationary phases and the retention property can be easily regulated by copolymer.

Extraction of W, V, and As from spent SCR catalyst by alkali pressure leaching and the pressure leaching mechanism.

Spent selective catalytic reduction (SCR) catalysts are environmentally hazardous and resource-enriching. In this work, V, W, and As in a spent SCR catalyst was extracted by alkali pressure leaching. Results showed that the V, W, and As were loaded on the anatase TiO2 crystal grains as amorphous oxides. The optimum pressure leaching conditions were NaOH concentration of 20 wt%, reaction temperature of 180 °C, reaction time of 120 min, L/S of 10 mL/g, and stirring speed of 300 rpm. The leaching efficiency of W, V, and As reached 98.83%, 100%, and 100%, respectively. The experiment revealed the preferential leaching of V and As rather than W, and the leaching mechanisms of V, W, and As were studied through experiment and density functional theory (DFT). The leaching kinetics of W conformed to a variant of the shrinking core model and the leaching process of W is controlled by both chemical reactions and diffusion processes. During the leaching process, Na2Ti2O4(OH)2 product powder layer was generated, which affects the mass transfer of W. The destruction of the TiO2 skeleton in the spent SCR catalyst is essential for adequate W extraction, especially for the extraction of W embedded in the TiO2 lattice. The DFT simulation result indicated that the V and As loaded onto the TiO2 support are easier to absorb hydroxide ions rather than W, and the leaching reaction energy of V and As was lower than W, As, and V has leaching priority over the leaching of W. Furthermore, an anatase TiO2 photocatalyst with the {001} crystal surface exposed was successfully prepared from the alkali pressure leaching residue. This work provides theoretical support for the metal leaching and utilization of spent SCR catalysts via alkali pressure leaching.

Grading of Glioma: combined diagnostic value of amide proton transfer weighted, arterial spin labeling and diffusion weighted magnetic resonance imaging.

BACKGROUND: To investigate the ability of amide proton transfer (APT) weighted magnetic resonance imaging (MRI), arterial spin labeling (ASL), diffusion weighted imaging (DWI) and the combination for differentiating high-grade gliomas (HGGs) from low-grade gliomas (LGGs). METHODS: Twenty-seven patients including nine LGGs and eighteen HGGs underwent conventional, APT, ASL and DWI MRI with a 3.0-T MR scanner. Histogram analyses was performed and quantitative parameters including mean apparent diffusion coefficient (ADC mean), 20th-percentile ADC (ADC 20th), mean APT (APT mean), 90th-percentile APT (APT 90th), relative mean cerebral blood flow (rCBF mean) and relative 90th-percentile CBF (rCBF 90th) were compared between HGGs and LGGs. The diagnostic performance was evaluated with receiver operating characteristic (ROC) analysis of each parameter and their combination. Correlations were analyzed among the MRI parameters and Ki-67. RESULTS: The APT values were significantly higher in the HGGs compared to the LGGs (p <  0.005), whereas ADC values were significantly lower in HGGs than LGGs (P <  0.0001). The ADC 20th and APT mean had higher discrimination abilities compared with other single parameters, with the area under the ROC curve (AUC) of 0.877 and 0.840. Adding ADC parameter, the discrimination ability of APT and rCBF significantly improved. The ADC was negatively correlated with the APT and rCBF value, respectively, while APT value was positively correlated with rCBF value. Significant correlations between ADC values and Ki-67 were also observed. CONCLUSIONS: APT and DWI are valuable in differentiating HGGs from LGGs. The combination of APT, DWI and ASL imaging could improve the ability for discriminating HGGs from LGGs.

Efficient and stable catalyst of α-FeOOH for NO oxidation from coke oven flue gas by the catalytic decomposition of gaseous H2O2.

Goethite (α-FeOOH) possesses excellent catalytic activity, high selectivity and good stability as a catalyst for NO oxidation through the catalytic decomposition of gaseous H2O2. as the primary reactive oxygen species is involved in the NO oxidation process together with ·OH, and N2O5 is found for the first time in the products of NO oxidation.

Protective effects of Weilikang decoction on gastric ulcers and possible mechanisms.

Although Weilikang decoction (WLK) has been used for gastric ulcer (GU) therapy in a clinical setting with good curative effect for >20 years, the mechanism remains unclear. Several GU animal models, induced by ethanol, hydrochloric acid, aspirin, pylorus ligation, acetic acid and indomethacin, were used to investigate the gastroprotective effects of WLK decoction. Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME), indomethacin, and N-ethylmaleimide (NEM) were pretreated, respectively, to investigate the action mechanism. Real-time polymerase chain reaction and Western blot analysis methods were used to determine the effects of WLK on indomethacin-induced GUs. The WLK-administered groups (2.5, 1.25 and 0.625 g/kg) significantly reduced the GU areas induced by ethanol, hydrochloric acid and aspirin. Furthermore, the effects could be quenched by L-NAME and NEM, but not by indomethacin. The 2.5 and 1.25 g/kg WLK groups showed significantly decreased effects on GU areas induced by pylorus ligation and acetic acid. WLK treatment significantly decreased mRNA expression on cyclooxygenase (COX)-1, COX-2, interleukin-6, tumor necrosis factor α and inducible nitric oxide synthase (iNOS) mRNA, but showed no effect on endothelial nitric oxide synthase mRNA expression. Western blot analysis result showed that WLK-treated groups markedly downregulated COX-2 protein expression. The anti-ulcer potential of WLK can be primarily attributed to its regulatory effects on nitric oxide, sulfhydryl compounds, and reduction effect on mucosal expression of proinflammatory cytokines.

Cost-effective reduced graphene oxide-coated polyurethane sponge as a highly efficient and reusable oil-absorbent.

Reduced graphene oxide coated polyurethane (rGPU) sponges were fabricated by a facile method. The structure and properties of these rGPU sponges were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, X-ray diffraction, and scanning electron microscopy. The rGPU sponges are hydrophobic and oleophilic and show extremely high absorption for organic liquids. For all the organic liquids tested, the absorption capacities were higher than 80 g g(-1) and 160 g g(-1) (the highest value) was achieved for chloroform. In addition, the absorption capacity of the rGPU sponge did not deteriorate after it was reused 50 times, so the rGPU sponge has excellent recyclability.

An environmentally friendly method for the fabrication of reduced graphene oxide foam with a super oil absorption capacity.

Three kinds of graphene oxide (GO) foams were fabricated using different freezing methods (unidirectional freezing drying (UDF), non-directional freezing drying, and air freezing drying), and the corresponding reduced graphene oxide (RGO) foams were prepared by their thermal reduction of those GO foams. These RGO foams were characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The absorption process and the factors that influence the absorption capacity were investigated. The RGO foams are hydrophobic and showed extremely high absorbing abilities for organic liquids. The absorption capacity of the RGO foams made by UDF was higher than 100 g g(-1) for all the oils tested (gasoline, diesel oil, pump oil, lubricating oil and olive oil) and had the highest value of about 122 g g(-1) for olive oil. The oil absorption capacity of the GO foams was lower than that of the RGO foams, but for olive oil, the absorption capacity was still high than 70 g g(-1), which is higher than that of most oil absorbents.