miR-200c overexpression inhibits the invasion and tumorigenicity of epithelial ovarian cancer cells by suppressing lncRNA HOTAIR in mice.

Epithelial ovarian cancer (EOC) is a common ovarian cancer in gynecological cancers today. It has been found that microRNAs and long-chain noncoding RNA (lncRNA) regulate the gene transcriptional expression in cells. However, it is not well understood that the upstream and downstream regulatory molecules of lncRNA HOX antisense intergenic RNA (HOTAIR). The effects of miR-200c overexpression on the invasion and nude mouse tumorigenicity, as well as lncRNA HOTAIR and snail expression of EOC SKOV3 cells, should be further explored. The expression of miR-200c and lncRNA HOTAIR was detected by reverse transcription PCR (RT-PCR) in EOC SKOV3 cells. The whole miR-200c gene fragment was cloned into a lentiviral plasmid vector. The miR-200c expression in transducted SKOV3 cells with reconstructed miR-200c lentivirus was significantly higher than the negative control (P < .01). The lentivirus-miR-200c-SKOV3 cells show that the invasion ability was significantly decreased compared with the negative control (P < .01). The nude mouse tumorigenicity was significantly decreased compared with that of the control group (P < .01). The snail protein expression in lentivirus-miR-200c-SKOV3 xenograft tumor was significantly decreased compared with the negative control lentivirus-SKOV3 group (P < .05). The miR-200c overexpression significantly decreased the expressions of lncRNA HOTAIR and snail, but increased E-cadherin expression in the lentivirus-miR-200c transducted SKOV3 cells of xenograft tumor, compared with the negative control (P < .05). The miR-200c overexpression in SKOV3 cells with transducted lentivirus-miR-200c can inhibit lncRNA HOTAIR expression, decrease snail, increase E-cadherin and significantly reduce the invasion and tumorigenicity of EOC SKOV3 cells. These results suggest that the miR-200c and lncRNA HOTAIR could be effective therapeutic targets for human epithelial ovarian cancer treatment.

[Effects of Targeting lncRNA HOTAIR on the Invasion and Nude Mouse Tumorigenicity of Epithelial Ovarian Cancer Cells].

OBJECTIVE: To explore the effects of shRNA-mediated downregulating lncRNA HOTAIR on the invasion,nude mouse tumorigenicity and snail expression of epithelial ovarian cancer SKOV3 cells. METHODS: The expression of lncRNA HOTAIR was detected by RT-PCR in SKOV3 cells. The shRNA targeting the lncRNA HOTAIR gene was cloned into RNA interference plasmid. The construction shHOTAIR vector was transfected into ovarian cancer SKOV3 cells by lipofectamine 2000,and the stably transfected cells were isolated by G418 and single clone selection. The downregulating expression of lncRNA HOTAIR was detected by quantitative real time PCR(qRT-PCR). The characteristics of shHOTAIR transfected SKOV3 cells were analyzed from the assays of invasion and nude mouse tumorigenicity,as well as the expression of snail and E-cadherin mRNA detected by qRT-PCR,and snail detected by immunohistochemistry and Western blot methods in xenograft tumor,respectively. RESULTS: The lncRNA HOTAIR expression was proved by RT-PCR in SKOV3 cells. The lncRNA HOTAIR expression in shHOTAIR transfected SKOV3 cells was significantly lower than the scramble control (P<0.01). The shHOTAIR transfected SKOV3 cells show that the invasion ability was significantly decreased compared with the scramble control (P<0.01). The nude mouse tumorigenicity,including tumorigenicity mouse number and tumor volume,was significantly decreased compared with the control group (P<0.01). The snail protein expression detected by IHC and Western blot in shHOTAIR-SKOV3 xenograft tumor was significantly decreased compared with the control scramble- SKOV3 group (P<0.05). The lncRNA HOTAIR low expression resulted in increasing E-cadherin and decreasing snail expression detected by qRT-PCR in the shHOTAIR transfected SKOV3 cells of xenograft tumor,compared with the scramble control (P<0.05). CONCLUSION: Targeting lncRNA HOTAIR expression in SKOV3 cells with RNA interference can decrease snail,increase E-cadherin and significantly reduce the invasion and tumorigenicity of epithelial ovarian cancer SKOV3 cells. These results suggest that the lncRNA HOTAIR could be an effective therapeutic target for human epithelial ovarian caner treatment.

Downregulated lincRNA HOTAIR expression in ovarian cancer stem cells decreases its tumorgeniesis and metastasis by inhibiting epithelial-mesenchymal transition.

BACKGROUND: Emerging evidence indicates that dysregulated long intervening non-coding RNA (lincRNA) HOTAIR correlates highly with tumor invasion and metastasis but a link between the high expression of HOTAIR and the metastatic cascade of cancer stem cells (CSCs) needs to be further studied. The purpose of this study was to investigate the effect of down-regulated HOTAIR expression on tumorgeniesis and metastasis of epithelial ovarian cancer (EOC) CSCs. CD117(+)CD44(+)CSCs were isolated from human EOC SKOV3 cell line by using a magnetic-activated cell sorting system, and were then transfected with the expression vector-based small hairpin RNA targeting HOTAIR; the stably transfected cells were selected for the study. Colony-forming, wound-healing, cellular metastasis and tumorigenicity assays were performed. RESULTS: The results demonstrated that the HOTAIR expression in clinical EOC tissues and SKOV3 CD117(+)CD44(+)CSCs was higher than in SKOV3 tumor tissues and non-CD117(+)CD44(+)CSCs. The CD117(+)CD44(+)-shHOTAIR showed an inhibited HOTAIR expression, reduced cell migration and invasion than CD117(+)CD44(+)- scramble, suggesting the inhibition of an epithelial-mesenchymal transition. Moreover, the downregulated HOTAIR expression in CD117(+)CD44(+) CSCs significantly decreased the tumor growth and lung metastasis in xenograft mice. CONCLUSION: Our findings demonstrated the shHOTAIR-mediated down-regulation of the HOTAIR expression in CD117(+)CD44(+) CSCs can be a promising new opportunity for future clinical trials.

Effect of downregulation of ZEB1 on vimentin expression, tumour migration and tumourigenicity of melanoma B16F10 cells and CSCs.

Zinc-finger E-box binding homeobox 1 (ZEB1) is a master regulator of epithelial-mesenchymal transition (EMT) and has been implicated in primary epithelial cancer biological processes, such as invasion and metastasis. However, the role of ZEB1 in progression of melanoma and cancer stem cells (CSCs) remains obscure. In this study, the recombinant plasmids of t3 shRNAs targeting mouse ZEB1 were constructed and transfected into melanoma B16F10 cells. The stable transfected cells were selected and the characteristics of ZEB1 downregulated B16F10 cells was assessed. The tumourigenicity of CD44(+) CD133(+) CSCs isolated from B16F10 cells stably transfected with the ZEB1-shRNA2 recombinant was also assessed. ZEB1-shRNAs B16F10 showed a lower expression of ZEB1 and vimentin, weaker migration, invasiveness, colony forming, and proliferation, and a lower tumourigenicity than the control cells. The tumourigenicity of the ZEB1-shRNA2 CD44(+) CD133(+) CSCs was also inhibited. In conclusion, ZEB1-shRNA2-mediated downregulation of ZEB1 expression in B16F10 cells and CSCs is involved in the inhibition of the EMT process. ZEB1 may be a potential target in melanoma targeted.

[Preliminary study of the inhibitory effect and mechanism of B16F10-ESAT-6-gpi/IL-21 vaccine on the pulmonary metastasis in mouse models of melanoma].

OBJECTIVE: To investigate the effect and mechanism of B16F10-ESAT-6-gpi/IL-21 tumor cell vaccine on pulmonary metastasis in mouse model of melanoma. METHODS: Twelve 8-week old female C57BL/6 mice were used in this study. The mice were injected with wild-type B16F10 cells through tail vein after immunization with B16F10-ESAT-6-gpi/IL-21 tumor cell vaccine, and the pulmonary metastasis was observed. The CD4(+) and CD8(+) T cells were isolated by magnetic activated cell sorting, and then used for the detection of CFSE/7-AAD cytotoxicity by flow cytometry. Serum from the mice immunized with tumor-cell vaccine was used to detect IFN-γ expression by ELISA. The expression of TGF-ß2, ZEB1, E-cadherin, and N-cadherin of tumor tissues was detected by RT-PCR and immunofluorescence, respectively. RESULTS: The mice vaccinated with B16F10-ESAT-6-gpi/IL-21 had significantly fewer nodules in the lung and lower lung weight [(285.8 ± 19.01) mg vs. (406.3 ± 27.12) mg], with lower levels of TGF-ß2, ZEB1 and N-cadherin proteins but higher level of E-cadherin protein within the tumor tissue, as compared with the control mice. Meanwhile, the immunized mice had significantly increased CD8(+) T cell killing activity [(42.62 ± 3.465)% vs. (22.29 ± 1.804)%] and IFN-γ expression level [(55.200 ± 7.173) pg/ml vs. (6.435 ± 1.339) pg/ml] over the control mice. CONCLUSIONS: The B16F10-ESAT-6-gpi/IL-21 vaccine can inhibit the metastasis of melanoma in the lung in vaccinated melanoma-bearing mice. This inhibitory effect is associated with CD8(+) T cell immune response and a higher level of IFN-γ, which may influence on the mesenchymal-epithelial transition of tumor cells.

Evaluation of characteristics of CD44+CD117+ ovarian cancer stem cells in three dimensional basement membrane extract scaffold versus two dimensional monocultures.

BACKGROUND: Cancer stem cells (CSCs) are thought to be capable of surviving conventional chemotherapeutic treatments because the cells have more resistant to anticancer drugs than common cancer cells. Most in vitro studies in experimental cancer cells have been done in a two-dimensional (2D) monocultures, while accumulating evidence suggests that cancer cells behave differently when they are grown within a three-dimensional (3D) culture system. RESULTS: The CD44+CD117+cells isolated from human epithelial ovarian cancer SKOV-3 cell line using magnetic-activated cell sorting were found to grow faster than the SKOV-3 cells in the 3D culture and in the nude mice. Anticancer drugs 5FU, docetaxel, cisplatin, and carboplatin were seen to inhibit growth of the CD44+CD117+ cells by 50% in the 2D culture with IC50 concentration, whereas, in the 3D culture, the four drugs inhibited the cell growth by only 34.4%, 40.8%, 34.8% and 21.9% at 3D one, respectively. Effect of paclitaxel on the CD44+CD117+cell viability indicated that fewer cells underwent apoptosis in 3D culture than that in 2D one. In addition, anticancer drugs markedly increased the expression of ABCG2 and ABCB1 of CD44+CD117+cells in 3D culture. CONCLUSION: Our assay demonstrated that human epithelial ovarian cancer CD44+CD117+cells possessed the properties of CSCs that exhibited more chemoresistance in the 3D culture than that of in 2D one. The 3D culture provides a realistic model for study of the CSC response to anticancer drugs.

Effect of down-regulated transcriptional repressor ZEB1 on the epithelial-mesenchymal transition of ovarian cancer cells.

BACKGROUND: Progress has been made against early events of malignant transformation and drug resistance associated with epithelial ovarian cancer; uncontrolled metastases, however, still accounts for most patient deaths. The molecular mechanism that regulates the process of epithelial ovarian cancer metastases is not yet clearly understood. The purpose of this study was to investigate the effect of down-regulating the transcriptional repressor zinc-finger E-box-binding homeobox 1 (ZEB1) on an epithelial-mesenchymal transition (EMT) of human ovarian cancer SKOV3 cell line in vitro and in vivo. METHODS: The human ovarian cancer cells SKOV3 and HO8910 were transfected with an expression vector-based small hairpin RNA (shRNA) targeting ZEB1 (shZEB1), and the stably transfected cells were selected. Colony-forming, wound-healing, and cellular migration assays were respectively used. The tumorigenicity of shZEB1-SKOV3 was also evaluated in mice. RESULTS: The shZEB1-SKOV3 and shZEB1-HO8910 cells showed a lower level of ZEB1 expression and weaker cell migration than the control cells. Moreover, down-regulating ZEB1 expression with shRNA in the cells enhanced the expression of miR-200c that acted as a tumor suppressor to inhibit the epithelial-mesenchymal transition of shZEB1-SKOV3 cells and to block shZEB1-SKOV3 cell metastasis in vivo. The shRNA-mediated down-regulation ZEB1 in SKOV3 cells significantly decreased the tumor growth in the xenograft mice. CONCLUSION: The shZEB1-mediated down-regulation of the ZEB1 expression in the SKOV3 cells may be considered for future clinical trials.

Hydrothermal Pretreatment of KOH for the Preparation of PAC and Its Adsorption on TC.

The environment has been heavily contaminated with tetracycline (TC) due to its excessive use; however, activated carbon possessing well-developed pores can effectively adsorb TC. This study synthesized pinecone-derived activated carbon (PAC) with high specific surface area (1744.659 cm2/g, 1688.427 cm2/g) and high adsorption properties (840.62 mg/g, 827.33 mg/g) via hydrothermal pretreatment methods utilizing pinecones as precursors. The results showed that PAC treated with 6% KOH solution had excellent adsorption properties. It is found that the adsorption process accords with the PSO model, and a large amount of C=C in PAC provides the carrier for π-πEDA interaction. The results of characterization and the isothermal model show that TC plays a key role in the adsorption process of PAC. It is concluded that the adsorption process of TC on PAC prepared by hydrothermal pretreatment is mainly pore filling and π-πEDA interaction, which makes it a promising adsorbent for TC adsorption.

LncRNA HOTAIR down-expression inhibits the invasion and tumorigenicity of epithelial ovarian cancer cells by suppressing TGF-ß1 and ZEB1.

BACKGROUND: Epithelial ovarian cancer (EOC) is a pathological type with a higher mortality rate among gynecological cancers today. Long-chain noncoding RNAs (lncRNAs) can regulate the transcription and expression of cellular genes. However, the downstream molecules regulated by lncRNA HOTAIR have not been well studied. The effects of downregulated lncRNA HOTAIR on EOC invasiveness and tumorigenicity in nude mice, along with TGF- ß1 and ZEB1 in epithelial ovarian cancer cells, need to be investigated in further research. RESULTS: RT-qPCR was used to detect lncRNA HOTAIR and TGF-ß1 and ZEB1 mRNA expression in EOC SKOV3 cells. The expression of lncRNA HOTAIR in SKOV3 cells transfected with the recombinant shHOTAIR interference plasmid was significantly lower than that of the negative control. Compared with the negative control, the matrix gel invasion ability of shHOTAIR SKOV3 cells in vitro and their tumorigenicity in nude mice were significantly reduced. Moreover, compared with the control, the expression of ZEB1 protein in shHOTAIR-SKOV3 xenograft tumors was significantly reduced. Downregulation of lncRNA HOTAIR expression significantly reduced TGF-ß1 and ZEB1 mRNA expression, but increased the expression of E-cadherin mRNA. In summary, downregulated lncRNA HOTAIR in EOC SKOV3 cells transfected with shHOTAIR can inhibit TGF-ß1, reduce ZEB1, increase E-cadherin, and significantly reduce the invasiveness and tumorigenicity of ovarian epithelial cancer SKOV3 cells. CONCLUSIONS: These results suggest that the lncRNA HOTAIR may be an effective target for the treatment of human EOC.

Photochemical synthesis of group 10 metal nanoclusters for electrocatalysis.

Four group 10 metal nanoclusters, Ni10(4-MePhS)20, Ni11(PhS)22, Pd9(PhS)18 and Pd10(PhS)20 were synthesized from disulfides based on a photochemical reduction-oxidation cascade process, which proceeds via a different mechanism to that of the conventional two-step reduction process. The as-obtained nanoclusters possess oxidative resistance and structural robustness under different conditions. Their atomically precise structures are determined to be nickel or palladium rings in which the metal atoms are bridged by Ar-S groups. Their catalytic performance in oxygen reduction reaction was compared, and the ring size-dependent catalytic activity of the group 10 metal nanoclusters was revealed. This work provides an efficient route to atomically precise and structurally stable group 10 metal nanoclusters, and sheds light on their further applications in electrocatalysis.

Human umbilical blood mononuclear cell-derived mesenchymal stem cells serve as interleukin-21 gene delivery vehicles for epithelial ovarian cancer therapy in nude mice.

Ovarian cancer causes more deaths than any other cancer of the female reproductive system, and its overall cure rate remains low. The present study investigated human umbilical blood mononuclear cell (UBMC)-derived mesenchymal stem cells (UBMC-MSCs) as interleukin-21 (IL-21) gene delivery vehicles for ovarian cancer therapy in nude mice. MSCs were isolated from UBMCs and the expanded cells were phenotyped by flow cytometry. Cultured UBMCs were differentiated into osteocytes and adipocytes using appropriate media and then the UBMC-MSCs were transfected with recombinant pIRES2-IL-21-enhancement green fluorescent protein. UBMC-MSCs expressing IL-21 were named as UBMC-MSC-IL-21. Mice with A2780 ovarian cancer were treated with UBMC-MSC-IL-21 intravenously, and the therapeutic efficacy was evaluated by the tumor volume and mouse survival. To address the mechanism of UBMC-MSC-IL-21 against ovarian cancer, the expression of IL-21, natural killer glucoprotein 2 domain and major histocompatibility complex class I chain-related molecules A/B were detected in UBMC-MSC-IL-21 and in the tumor sites. Interferon-γ-secreting splenocyte numbers and natural killer cytotoxicity were significantly increased in the UBMC-MSC-IL-21-treated mice as compared with the UBMC-MSCs or the UBMC-MSC-mock plasmid-treated mice. Most notably, tumor growth was delayed and survival was prolonged in ovarian-cancer-bearing mice treated with UBMC-MSC-IL-21. Our data provide important evidence that UBMC-MSCs can serve as vehicles for IL-21 gene delivery and inhibit the established tumor.

Technical and Benefit Evaluation of Fruit-Wood Waste Gasification Heating Coproduction of an Activated Carbon System.

Biomass gasification polygeneration technology can well address both the economic and environmental issues that impeded the development of biomass gasification technology. To further improve the utilization efficiency of biomass, preactivation of gasified carbon is realized in the gasification reactor. The aim of this study is to adopt a new gasification reactor and an environmental protection combustion chamber to obtain high value-added activated carbon with clean heating. In this paper, an experimental study on the fruit-wood waste gasification heating coproduction of an activated carbon system was carried out. The results show that the yield of gasified carbon is 20.22%, the specific surface area of gasified carbon reaches 590 m2/g, the yield of activated carbon is 10.37%, and the gas yield is 1.9 Nm3/kg. The gasification efficiency of the system is 57.83%, the energy that is transferred to the activated carbon is 18.72%, and the percentage of fixed carbon is 24.3%. Compared with the biomass particle, coal, and natural gas heating projects, the environmental protection benefits of the project are significant, and the negative emission of CO2 is realized. Compared with the heating benefit of coal and natural gas, the economic benefit of this project is more significant.

Comparative Study on the Pyrolysis Behaviors of Pine Cone and Pretreated Pine Cone by Using TGA-FTIR and Pyrolysis-GC/MS.

Pine cone (PC) is a potential biomass energy source and is rich in nonstructural substances (NSS). To understand the impact of these NSS on the pyrolysis behavior and its products, in this study, phenol alcohol extraction was used for the separation of NSS from PC (the PC after separation of NSS was labeled as A-PC), and then thermogravimetric analysis -Fourier transform infrared and PY-gas chromatography/MS detection techniques were used to conduct a systematic comparison of the thermal degradation behaviors and kinetics parameters of PC and A-PC. Results showed that the N content of PC was higher than that of other biomass, and the activation energies of PC and A-PC generally decreased at first and then increased as the conversion rate increased. Furthermore, the activation energy of PC decreased with conversion rates in the range of 0.25-0.30, while A-PC lagged significantly behind PC. On the other hand, the maximum absorption peak of CH4 for PC was higher than that of A-PC, and the maximum absorption peak of CO2 was quite the opposite. After extracting NSS from the PC, its activation energy was significantly increased.

Enhancement of the production of bio-aromatics from renewable lignin by combined approach of torrefaction deoxygenation pretreatment and shape selective catalytic fast pyrolysis using metal modified zeolites.

In this work, combined approach of torrefaction deoxygenation pretreatment (TDP) and shape selective catalytic fast pyrolysis (SS-CFP) using bifunctional catalyst (metal modified HZSM-5) were employed to improve the yield of bio-BTX derived from the renewable starting material of lignin. Results showed that after TDP, the oxygen element could be removed effectively. The oxygen removal efficiency reached its maximum value of 22.27% at 300 °C, resulting in markedly decrease of unnecessary oxygenates in bio-oil. Compared to parent HZSM-5, all metal modified HZSM-5 (Ga/HZSM-5, Zn/HZSM-5, and Ga-Zn/HZSM-5) promoted the formation of bio-BTX. Zn/HZSM-5 showed the highest selective yield of bio-BTX because of the enhancement deoxygenation reaction of oxygenates and the aromatization reaction of olefins. The combined approach of TDP and SS-CFP remarkably improved the selective yield of bio-BTX, reaching the maximum value of 65.19%, which was much higher than that from single approach of TDP (33.84%) and SS-CFP (47.36%).

Upgrading of bio-oil via solar pyrolysis of the biomass pretreated with aqueous phase bio-oil washing, solar drying, and solar torrefaction.

In this study, three types of biomass were first pretreated with an aqueous phase bio-oil instead of traditional acid washing. Then, the washed samples were pretreated with drying (100 â„ƒ, 30 min) and torrefaction (250 â„ƒ, 30 min) using a parabolic-trough solar receiver system. The subsequent pyrolysis was performed at 550 â„ƒ for 10 min using a parabolic-dish solar receiver system. Results showed that the solar energy can effectively ensure the temperature required for biomass drying, torrefaction, and pyrolysis, having thus a potential to replace the conventional electric heating or fossil fuel heating. Such a strategy combines the advantages of the independent pretreatments, i.e., leaching out of metallic species and reduction of oxygen content. Consequently, the high heating value of bio-oil increased remarkably, the generation of acids was strongly inhibited, whereas the formation of phenols and anhydrosugars was promoted. Therefore, the method proposed herein is promising for upgrading of biomass and bio-oil.

Study on antibiotic susceptibility of Salmonella typhimurium L forms to the third and forth generation cephalosporins.

Salmonella typhimurium is a pathogenic gram-negative bacterium, which is found primarily in the intestinal lumen. It often causes diarrhea in infants and young children and leads to food poisoning. Drug resistance of Salmonella typhimurium presented serious complications in clinical patients. In this study, we investigated the antibiotic susceptibility of Salmonella typhimurium standard strain L forms to the third and forth generation cephalosporins, in order to control and eliminate Salmonella typhimurium L forms in infection treatment. Salmonella typhimurium L forms were induced by ß-lactam antibiotic cefazolin in the culture medium of bacterial L forms. The antibiotic susceptibility of Salmonella typhimurium L forms was analyzed by K-B drug susceptibility testing. The change trend of drug susceptibility and resistance of Salmonella typhimurium L forms was obtained in accordance with USA clinical and laboratory standards institute (CLSI) evaluation data and statistical analysis. Drug resistance of Salmonella typhimurium L forms showed little increasing trend compared with their parent bacteria. The L form inhibition zone was smaller than in the parent bacteria. However, the drug susceptibility of L forms of Salmonella typhimurium to the third and forth generation cephalosporins remained sensitive.The antibiotic susceptibility of Salmonella typhimurium L forms to the third and forth generation cephalosporins remains sensitive, and the combined use of multi-antibiotics is a convenient and effective method to reduce Salmonella typhimurium L forms occurrence.

Features and Commercial Performance of a System of Biomass Gasification for Simultaneous Clean Heating and Activated Carbon Production.

Biomass is a renewable and clean energy. Moreover, clean heating plays a vital role in solving issues related to the heating source structures in northern China. This paper reports on our novel technology: a system of biomass (mainly fruitwood waste, referred to in short as FWW) gasification for simultaneous clean heating and fruitwood activated carbon (FAC) production. In particular, we will discuss the features of our gasification system and product characteristics, as well as energy efficiency, environmental benefits, and economic benefits. The results showed that the energy conversion from FWW gasification was as follows: 48.10% hot gas, 49.08% fruitwood gasified carbon (FGC), and 2.82% energy loss. The NO x emissions of this system were about 126 mg/Nm3. The iodine adsorption values of the derived FGC and FAC were about 550 and 1000 mg/g, respectively. The system of gasification consumed 36 t of FWW per day, obtained 10 t of FGC, and produced 5 t of FAC. The emissions of CO2 were neutral during the operation, and the clean heating area was 4100 m2/d in Chengde, Hebei, China, with the payback period under one heating season. These results show that the system is practical, economical, energy-saving, and environmentally friendly.

Investigation of the relevance between biomass pyrolysis polygeneration and washing pretreatment under different severities: Water, dilute acid solution and aqueous phase bio-oil.

Washing pretreatments of rice straw were performed using three different solutions, namely water, dilute hydrochloric acid solution (HCl solution, pH = 2.9), and aqueous phase bio-oil (APBO, pH = 2.9). The raw and pretreated samples were pyrolyzed at 550 °C in a fixed bed reactor. Results showed that among the three pretreatments, washing with APBO had the highest removal efficiency of alkali metal and alkaline earth metals (AAEMs). Among the pyrolysis products, bio-oil from APBO washed sample had the highest mass, energy, and carbon yields, lowest water content of 36.9%, highest HHV of 17.2 MJ/kg, and highest relative content of anhydrosugars of 31.2%. Its biochar had the lowest ash content of 27.3% and highest specific surface area of 98.6 m2/g, and its non-condensable gases had the highest HHV of 11.9 MJ/m3. Therefore, APBO washing was effective in improving the quality of biomass and its subsequent pyrolysis products.

New sight on the lignin torrefaction pretreatment: Relevance between the evolution of chemical structure and the properties of torrefied gaseous, liquid, and solid products.

In order to reveal the deoxygenation mechanism of lignin torrefaction, the relevance between evolution of chemical structure of torrefied lignin and the properties of torrefied gaseous, liquid, and solid products was established in this study. Results showed that the contents of oxygen element, ßO4 linkages, oxygen-containing functional groups (aliphatic OH, aliphatic COOH, aromatic OCH3) in lignin decreased with the increase of the torrefaction temperature from 210 to 300 °C. The oxygen removal efficiency of lignin torrefaction reached the maximum value of 25.53% at 300 °C. The removed oxygen in the torrefied lignin was transferred into the torrefied gaseous product (e.g. CO2, H2O, and CO) and torrefied liquid product (e.g. G-type and P-type phenols, acids). Among the torrefied gaseous products, CO2 was the dominant oxygen carrier, followed by CO and H2O. Among the torrefied liquid products, G-type phenols were the dominant oxygen carrier, followed by P-type phenols and acids.

In-depth study of rice husk torrefaction: Characterization of solid, liquid and gaseous products, oxygen migration and energy yield.

Torrefaction is a promising method for biomass upgrading, and analysis of all products is the essential way to reveal torrefaction mechanism. In this study, torrefaction of rice husk was performed at 210-300 °C. Results showed that the fuel properties of solid products were greatly enhanced upon removal of oxygen. The gaseous products were mainly CO2 (52.9-73.8 vol%), followed by CO (26.3-39.2 vol%). The liquid product was mainly water and some tar, and the latter contained acids, furans, ketones, aldehydes, and phenols, among which the relative content of acids was the highest. Torrefaction temperature has obvious effects on the oxygen migration. Within the temperature range of 210-300 °C, 9.5-63.2% of oxygen in rice husk was migrated to the gaseous and liquid products. The H2O was the major contributor to deoxygenation, followed by CO2 and CO. Thus, formation of H2O, CO2, and CO during torrefaction is important as it achieves the purpose of intense deoxygenation.