RESUMEN
Ionic liquids (ILs) have been investigated to dissolve and/or pre-treat cellulose by combining with a low viscous co-solvent. Dissolution and pretreatment of cellulose by ILs are dynamic processes of dissolution and precipitation, which would caused the physical and chemical changes (such as crystallinity and thermal stability) of un-dissolved cellulose residues. Hence, this study focused on the thermal behavior of un-dissolved cellulose (PCEL) after pre-treatment using [BMIM]HSO4/ethanol. Ethanol was used as a green and cheap co-solvent of 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO4) to pre-treat cellulose under different conditions. The pretreatment effect on thermal behavior of PCEL was investigated by thermogravimetric analysis and the distributed activation energy model. [BMIM]HSO4/ethanol pretreatment efficiently lowered the thermal stability of cellulose, and promoted the thermal decomposition at low temperature. The thermal behavior of PCEL can be adjusted by the [BMIM]HSO4 mass concentration.
RESUMEN
BACKGROUND: Cryoablation is an interdisciplinary, widely used treatment approach for several types of solid tumors, making it difficult to obtain a comprehensive picture of its current status and popular research topics. This study aimed to use a bibliometric approach to understand important research themes and trends in cryoablation and oncology. METHODS: Literature studies on cryoablation and oncology from 2001 to 2020 were extracted from the Web of Science. A bibliometric analysis was performed based on the annual publication volume, several journal articles and local citation score, and distribution of keywords and trends in the literature using tools such as COOC version 9.94, VOSviewer version 1.6.17, and the bibliometrix version 3.1.3 R package. RESULTS: This study included 2793 publications. Total yearly publications have plateaued over the last 20 years. Five research themes were presented in the keyword network, including clinical applications of cryoablation in liver, lung, kidney, prostate, and skin cancers and comparison of cryoablation with other energy ablations. After 2012, 2 new research topics emerged: synergy between cryoablation and immunotherapy in tumors and cryoablation of Barrett esophagus. The high cited literatures are dominated by studies related to cryoablation for renal and prostate cancer treatment, but they also reflect the recent increasing interest in immunotherapy and bone metastases. Twenty important journals were identified, with Cryobiology publishing the most articles. CONCLUSION: Bibliometric analysis of studies related to tumor cryoablation can help researchers rapidly comprehend popular topics and determine future trends, guiding future research directions.
Asunto(s)
Esófago de Barrett , Criocirugía , Masculino , Humanos , Oncología Médica , Inmunoterapia , BibliometríaRESUMEN
In order to investigate the effects of temperature, residence time (RT) and methoxyl (OCH3) on the product distribution and vapor phase reactions during pyrolysis of complex solid fuels, three model phenolic representatives, phenol, guaiacol and syringol, were pyrolyzed at a residence time of 0.7 s, over a temperature range of 400 °C-950 °C, and at temperatures of 650 °C and 750 °C, in a RT region of 0.1 s-4.2 s. Increasing yields of CO and C1-C5 light hydrocarbons (LHs) with RT at 650 °C and 750 °C indicated that ring-reduction/CO elimination of phenolic compounds happened at 650 °C, and dramatically at 750 °C. The addition of OCH3 affects the product distribution and ring-reduction pathways: C5 LHs from phenol, C2 LHs, C4 LHs and C5 LHs from guaiacol, and C1-C2 LHs from syringol. CO2 yields increase with the addition of OCH3. CO2 was formed via benzoyl and a four-membered ring, which would compete with the CO formation. The addition of OCH3 promotes the formation of coke and tar. The decomposition pathways are discussed, based on the experimental data, focusing on ring-reduction reactions and the formation of CO/CO2 and C1-C5 LHs.