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Roasting is an important step in the pretreatment of biomass upgrading. Roasting can improve the fuel quality of biomass, reduce the O/C and H/C ratios in the biomass, and provide the biomass with a fuel quality comparable to that of lignite. Therefore, studying the structure and component evolution laws during biomass roasting treatment is important for the rational and efficient utilization of biomass. When the roasting temperature is 200–300 °C, the cellulose and hemicellulose in the biomass undergo a depolymerization reaction, releasing many monocyclic aromatic hydrocarbons with high reactivity. The proportion of monocyclic aromatic hydrocarbons in biomass roasting products can be effectively regulated by controlling the reaction temperature, residence time, catalyst, baking atmosphere, and other factors in the biomass roasting process. This paper focuses on the dissociation law of organic components in the pretreatment process of biomass roasting. [ABSTRACT FROM AUTHOR]

Wheat straw, a typical agricultural solid waste, was employed to clarify the effects of torrefaction on the structural features and combustion reactivity of biomass. Two typical torrefaction temperatures (543 K and 573 K), four atmospheres (argon, 6 vol.% O2, dry flue gas and raw flue gas) were selected. The elemental distribution, compositional variation, surface physicochemical structure and combustion reactivity of each sample were identified using elemental analysis, XPS, N2 adsorption, TGA and FOW methods. Oxidative torrefaction tended to optimize the fuel quality of biomass effectively, and the enhancement of torrefaction severity improved the fuel quality of wheat straw. The O2, CO2 and H2O in flue gas could synergistically enhance the desorption of hydrophilic structures during oxidative torrefaction process, especially at high temperatures. Meanwhile, the variations in microstructure of wheat straw promoted the conversion of N-A into edge nitrogen structures (N-5 and N-6), especially N-5, which is a precursor of HCN. Additionally, mild surface oxidation tended to promote the generation of some new oxygen-containing functionalities with high reactivity on the surface of wheat straw particles after undergoing oxidative torrefaction pretreatment. Due to the removal of hemicellulose and cellulose from wheat straw particles and the generation of new functional groups on the particle surfaces, the ignition temperature of each torrefied sample expressed an increasing tendency, while the Ea clearly decreased. According to the results obtained from this research, it could be concluded that torrefaction conducted in a raw flue gas atmosphere at 573 K would improve the fuel quality and reactivity of wheat straw most significantly. [ABSTRACT FROM AUTHOR]

Condensed tannins the polyphenolic compounds that are widespread in plants have been proved to have antitumor potential. Here, we purified the bioactive condensed tannins from leaves of Ulmus pumila L. and explored their structural characteristics, antitumor effect on TFK‐1 cholangiocarcinoma cells as well as the related potential mechanism. The UV–Vis, FT‐IR spectroscopy, ESI‐Full‐MS, and thiolysis‐HPLC‐ESI‐MS demonstrated that U. pumila condensed tannins (UCTs) consisted essentially of procyanidins with epicatechin as the main flavan‐3‐ol extension unit. The UCTs could significantly reduce the survival rate of human cholangiocarcinoma TFK‐1, SK‐CHA‐1, and MZ‐CHA‐1 cells with the better inhibitory effect on TFK‐1 cell proliferation. Flow cytometric assay showed that UCTs affected TFK‐1 survival by G2/M phase arrest and inducing apoptosis in a dose‐dependent manner. In addition, a total of 6592 differentially expressed genes (DEGs), consisting of 94 upregulated and 6498 downregulated DEGs, were identified between untreated and UCTs‐treated TFK‐1 cells using RNA‐seq technology. Enrichment analysis based on the KEGG database revealed that these DEGs were closely associated with cell cycle and p53 apoptotic signaling pathways. Furthermore, qRT‐PCR confirmed that treatment of UCTs to TFK‐1 cells caused significant changes in the expression of cyclin E, cdc25 A, cytochrome c, caspase‐3, and caspase‐8. These results indicated that UCTs exhibited the growth inhibition effect on TFK‐1 cells possibly via G2/M cell cycle arrest and activation of caspase‐cascade to induce apoptosis, and had potential as an anti‐cholangiocarcinoma drug for further development. Practical applications: Ulmus pumila L. as a valuable tree species has been widely used in fields of medicine and food. Condensed tannins, the polyphenolic compounds widespread in plants, have been proved to have antitumor potential and be safe to normal cells. In this study, the condensed tannins from leaves of U. pumila (UCTs) remarkably suppressed cholangiocarcinoma (CCA) cell viability possibly via G2/M cell cycle arrest and activation of caspase‐cascade to induce apoptosis. The results provided evidence for the application of UCTs as a potential therapeutic drug for CCA tumor. [ABSTRACT FROM AUTHOR]

In an attempt to achieve the clean and efficient utilization of lignite, drying pre‐treatment was performed in this study before lignite combustion. The combustion reactivity and NO emission characteristics of the partially dried lignite samples in the char combustion stage were investigated by means of TG and isothermal combustion tests, and the reactivity could be summarized as the following order: L1>L0.5>raw>L3>LT>L5 (chars obtained from the devolatilization of the raw and partially dried coals at 378 K for 0.5, 1, 3, 5, and 120 minutes) and the NO conversion ratio of L1 was the lowest. When the moisture content in the coal particles was relatively high (19.68%‐35.84%), the drying treatment could increase the combustion reactivity and inhibit NO emission in the char combustion stage; When the moisture content was within a relatively low range (0.17%‐19.68%), the moisture removal had negative effects on the reactivity and NO emission in the char combustion stage. The surface behaviour and microstructure of the raw coal char and chars derived from the partially dried coals were clarified by temperature programmed desorption/reduction (TPD/TPR) and Raman spectroscopy. The results illustrated that L1 derived from Lc1 (19.68%) was the most reactive sample with the largest amount of C(O) on the particle surface. There were also more reactive aromatic structures in L1 than other samples. Compared with direct combustion or excessive drying treatment, lignite should be dried to a certain degree (19.68%) for optimized lignite combustion. [ABSTRACT FROM AUTHOR]

Abstract: A total of 12 hydrogen bonded complexes between the lowest energy tautomers of pyrimidinic bases of RNA and l-leucine have been characterized at the density functional level of theory with a hybrid B3LYP exchange-correlation functional and 6-311++G** basis set. The most stable complexes are formed when the carboxylic acid group of l-leucine is bound through two hydrogen bonds with a NH proton donor and an O proton acceptor of cytosine. And the imino group of l-leucine is not a good proton donor sites comparing with hydroxyl group. What is more, the cytosine is more sensitive to the alternative proton donor of the l-leucine. The interplay between the transformed H–X bonds'' structural parameters from two monomers to the dimer accompanying with the shifts of the frequency for the H–X stretching mode and interaction energies has been discussed. [Copyright &y& Elsevier]

Nonlinear optical vibrational spectroscopies are powerful experimental tools for inspecting material properties that are difficult to acquire otherwise. As ultrafast lasers used in such experiments are typically of much broader bandwidth than vibrational modes, narrowband filtering is usually essential, and the utility of laser energy is often highly inefficient. Here we introduce an experimental scheme to break this trade-off. A broadband beam is spatially chirped as it reaches the sample, and generates sum-frequency signals upon overlapping with another broadband, unchirped beam. A narrowband spectrum can then be retrieved from the spatially dispersed image of signals, with both broadband pulses fully utilized. The scheme is also readily employed as a spatially resolved spectroscopy technique without scanning, and can be easily extended to other wave-mixing experiments.

Objective: To compare the characteristics of esophageal gastric varices in portal hypertension patients with and without spontaneous shunts., Methods: Clinical data of 118 patients with esophageal gastric varices undergoing portal vein computed tomographic angiography (CTA) and gastroscopy between January 2012 and August 2015 was retrospectively reviewed., Results: Portal vein CTA results showed that spleno-renal or gastro-renal shunts were detected in 24 out of 118 cases. The average portal vein diameters (PVD) of patients with and without spontaneous shunt were (12.48±2.79) mm and (13.58±3.46) mm, respectively (P>0.05). The average area of gastric veins in patients with spontaneous shunt was significantly larger than that of patients without shunt [294.00 (0.00~2400.00) mm2 vs. 26.00 (0.00~1620.00) mm2, respectively, (P<0.001]. Compared with patients without spontaneous shunt, the location of esophageal varices was lower and the degree was less serious in patients with spontaneous shunt (P<0.05). No matter with history of uppergastrointestinal bleeding, the average area of gastric veins in patients with spontaneous shunt was significantly larger than that of patients without shunt (P<0.05). For patients having no history of splenectomy, the average portal vein diameter (PVD) in those with spontaneous shunt was significantly smaller than that in those without shunt (P<0.05)., Conclusion: The portal vein diameter of patients without splenectomy and with spontaneous shunts is shorter and their esophageal varices are less serious; the gastric veins are large and wriggly in patients with spontaneous shunts.