Biomass Conversion and Biorefinery
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2021
·Vol. 13
·期 12
·10701-10710
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IF 4.987
Zeng Qin,Du Zhenyu,Luo Ligang
In this study, different bimetallic (Ru, Pd, and Pt) catalysts over a variety of supports (activity carbon, γ-Al 2 O 3 , TiO 2 , HZSM-5) were employed to improve the kraft lignin depolymerization process using isopropanol as in situ hydrogen source. The effect of catalysts was firstly investigated, which suggested that 1wt%Ru-1wt% Pd/HZSM-5 promoted the hydrogenolysis and hydrodeoxygenation effect on conversion of kraft lignin (95.86 wt%) and the selectivity of aliphatic alcohol (26.92 wt%) and hydrocarbon monomers (35.73 wt%), respectively. The effect of temperature and reaction time were also discussed, which indicated that the high temperature (250 to 310 °C) promoted the hydrogenolysis process; while the temperature is higher than 310 °C, the repolymerization process was appeared, leading to the decreasing yield of total monomers. For the influence of reaction time, it was noted that the optimal reaction time to acquired high yield and selectivity of aliphatic alcohol and hydrocarbon monomer was 120 min. It was also conducted FTIR and 2D HSQC NMR analysis to understand the effective depolymerization of the major linkages with attacked by the Ru-Pd/HZSM-5 catalyst, which was corresponding with the results with GC–MS. Graphical abstract
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Molecular Therapy-Nucleic Acids
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2021
·
IF 8.886
Tingyu Zong,Yanyan Yang,Xiaotong Lin,Shaoyan Jiang,Hui Zhao,Meixin Liu,Yuanyuan Meng,Yong Li,Liang Zhao,Guozhang Tang,Kun Gong,Zhibin Wang,Tao Yu
Accumulating evidence shows that tRNA-derived fragments are a novel class of functional small non-coding RNA; however, their roles in aortic dissection (AD) are still unknown. In this study, we found that 5′-tiRNA-Cys-GCA was significantly downregulated in human and mouse models of aortic dissection. The abnormal proliferation, migration, and phenotypic transition of vascular smooth muscle cells (VSMCs) played a crucial role in the initiation and progression of aortic dissection, with 5′-tiRNA-Cys-GCA as a potential phenotypic switching regulator, because its overexpression inhibited the proliferation and migration of VSMCs and increased the expression of contractile markers. In addition, we verified that signal transducer and activator of transcription 4 (STAT4) was a direct downstream target of 5′-tiRNA-Cys-GCA. We found that the STAT4 upregulation in oxidized low-density lipoprotein (ox-LDL)-treated VSMCs, which promoted cell proliferation, migration, and phenotypic transformation, was reversed by 5′-tiRNA-Cys-GCA. Furthermore, 5′-tiRNA-Cys-GCA treatment reduced the incidence and prevented the malignant process of angiotensin II- and β-aminopropionitrile-induced AD in mice. In conclusion, our findings reveal that 5′-tiRNA-Cys-GCA is a potential regulator of the AD pathological process via the STAT4 signaling pathway, providing a novel clinical target for the development of future treatment strategies for aortic dissection.
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ENERGY & FUELS
·
2019
·
IF 3.021
Zhen-Yi Du,Bin-Bin Zhang,Ting-Sheng Chen,Yuli Betancur,Wen-Ying Li
Isobutanol derived from biomass can serve as a potential renewable candidate for the production of light olefins and aromatics, which are the building blocks to manufacture fuels and chemicals in the petrochemical industry. Dependent upon the product requirements, the product selectivity toward olefins or aromatics can be tuned by adjusting the reaction conditions and the properties of HZSM-5 catalysts. On bare HZSM-5, mild conditions (low temperature, low space time, and low acidity) favored the production of olefins and harsh conditions (high temperature, high space time, and high acidity) were more likely to produce aromatics. Ga was impregnated onto HZSM-5 to enhance the production of aromatics. Unexpectedly, Ga introduction only induced the intertransformation between olefins and aromatics without significantly impacting the selectivity of low-value paraffins. The exchanged Ga sites functioning together with Brønsted acid were identified as active Ga species and strengthened the direct dehydrogenation of C6–C8 olefins. The in situ-generated water from isobutanol dehydration affected the formation of Ga species. This resulted in different promotional effects of Ga on the transformation of isobutanol and isobutene. The reaction pathways were developed on the basis of the catalyst evaluation results, in tandem with an in situ diffuse reflectance infrared Fourier transform spectroscopy study on the intermediates formed during isobutanol transformation. Selectivity of olefins and aromatics from isobutanol transformation can be tuned by adjusting reaction conditions and properties of HZSM-5 catalysts.
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Changhui Zhu,Haiyong Wang,Hu Li,Bijuan Cai,Wei Lv,Chiliu Cai,Chenguang Wang,Long Yan,Qiying Liu,Longlong Ma
Alloyed Cu−Ni encapsulated in carbon was prepared by loading Ni and Cu onto biochar (BC) through an initial wetness impregnation method under mild conditions. The bimetallic catalysts were exploited to perform selective hydrodeoxygenation (HDO) of 5-hydroxymethylfurfural (HMF). 2,5-Dimethylfurfural (DMF), a promising liquid fuel/fuel additive, could be obtained from HMF with the highest yield of 93.5% under the optimized conditions. During HMF HDO, two key intermediates, 5-methylfurfural (MFF) and 2,5-dihydroxymethylfuran (DHMF), dominating two distinct conversion pathways were systematically investigated by Arrhenius kinetics analysis. In addition, the turnover frequencies (TOFs) of HDO reaction over Cu−Ni/BC corresponding with Cu amount were thoroughly discussed, finding that the electron transfer from Cu to Ni in the alloy structure was beneficial to the HDO reaction and the conversion pathways can be regulated by reaction temperature variation. Importantly, the synergy of HDO of HMF by alloyed Cu−Ni metal and Lewis acid sites from oxide NiOx were hence clarified by systematic catalyst characterizations. The Cu−Ni/BC catalyst is stable for at least five consecutive runs to obtain the stabilized 81.9% of DMF since the third run.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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2019
·Vol. 143
·期 1
·609-618
·
IF 2.471
Cao Chengyang,Zhang Dan,Lu Song,Liu Changcheng
Guanidinium-5-aminotetrazole (GA) was synthesized by mixing 5-aminotetrazole (5-AT) and guanidine carbonate in heated deionized water. The composite propellants containing GA and differential oxidizers (Sr(NO 3 ) 2 , KNO 3 , NaNO 3 ) were prepared, and its structural characteristics, thermal decomposition behavior, kinetics, thermal safety and burning characteristics were investigated. The thermal analysis results showed that the decomposition of GA based propellants could be separated into five stages, consisting of one phase change reaction, one exothermic reaction and three endothermic reactions. The reaction mechanisms of each decomposition stage were also researched and considered it was following reaction order models. The thermal safety evaluations were conducted using the obtained related parameters of the exothermic reaction. Combined with the burning characteristics measurement results, GA coupled with Sr(NO 3 ) 2 represented a higher thermal safety and more stale combustion process than other two propellant samples, which is also act as a promising formulation to substitute 5-AT based propellant in fire-fighting area.
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Iranian Journal of Basic Medical Sciences
·
2019
·
IF 1.854
Yan Yan,Fengling Ren,Pengchong Wang,Ying Sun,Jianfeng Xing
Objective(s): This study is aimed to design and synthesize a prodrug of 5-aminosalicylic acid and evaluate its ameliorative effect on experimental ulcerative colitis (UC). Materials and Methods: 5-Aminosalicylic acid-alanine (5-ASA-ALA) was synthesized and characterized. Its stability study was conducted in rat plasma and in the gastrointestinal tract environment, its transport characteristic was assessed using the Caco-2 cells. Its colon-targeting property was evaluated by the pharmacokinetic study, and incubation studies. A series of indicators were used to investigate its therapeutic effect on experimental colitis, including the survival rate and body weight of mice, the disease activity index (DAI), the colonic damage score and colon index, the myeloperoxidase (MPO) activity and the levels of malondialdehyde (MDA), total superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-Px) in colonic tissues. Results: 5-ASA-ALA was barely absorbed in the Caco-2 monolayer or into the rat blood. It was remarkably stable when incubated in the upper gastrointestinal tract, while gradually hydrolyzed in the colon of rats. When orally administered to mice, 5-ASA-ALA had significantly greater therapeutic effect on colitis than the positive control. Conclusion: 5-ASA-ALA is demonstrated to be a promising oral colon-targeting prodrug of 5-ASA and has potential application in UC treatment.
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JOURNAL OF POLYMER RESEARCH
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2019
·Vol. 26
·期 12
·1-12
·
IF 1.53
Jiao Yang,Chen Guofei,Zhou Haijun,Zhang Feng,Chen Xiaoqi,Li Yantao,Xiao Xueshan,Fang Xingzhong
A series of poly(benzimidazole-imide)s (PBIPIs) derived from different dianhydrides and 2-(3-aminophenyl)-5-aminobenzimidazole ( m -BIA) were synthesized via thermal imidization to form flexible films. This series of PBIPIs showed great T g s ranging from 296 to 484 °C, excellent thermal stability performed in 5% weight loss temperatures ( T d5% s) of 502–529 °C in N 2 and good mechanical properties (tensile strengths of 89–127 MPa, tensile moduli of 2.9–4.1 GPa and elongations at break of 3.9–6.9%). Compared with PIs derived from 6-amino-2-(4-(4-aminophenoxy)phenyl)-1H-benzimidazole ( p -BIODA), m -BIA based PBIPI films exhibited higher T g , and better solubility. Besides, the thermoplastic PBIPI resin (PI-6-PA) derived from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) and m -BIA exhibited good melt processability with high T g of 273 °C, melt flow index (MFI) of 7.76 g/10 min, minimum complex viscosity of 11.9 × 10 3 Pa·s at 402 °C and low melt viscosity ratio of 2.46 at 400 °C.
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Asian Pacific Journal of Tropical Medicine
·
2019
·
IF 1.772
Ni Pan-Li,Tian Shu-Hong,Yang Zhao-Xin,Zhang Jun-Qing,Yang Fan,Zhong Li-Fan,Gan Lian-Fang,Huang Mian-Qing,Huang Ling
Objective: To explore the effect of Feng-liao-chang-wei-kang ( FLCWK ) on acute and chronic gastroenteritis, synergistic effect on the growth inhibitory effect with 5-fluorouracil (5-FU) on colorectal cancer and its underlying mechanisms. Methods: In the in vitro study, HT-29 cells were divided into 5-FU alone, FLCWK alone and coadministration groups. The MTT assay was used to analyze the proliferation of HT-29 cells at 24 h. Flow cytometry was used to observe the apoptosis, cycle of colorectal cancer HT-29 cells at 24 h. In the in vivo experiment, The subcutaneous transplantation tumor model of colorectal cancer HT-29-Luc was established with nude mice. All mice were randomly divided into 5-FU alone, FLCWK alone and coadministration groups according to body weight. During administration, the Interactive Video Information System small animal live imaging system was used to monitor the growth of subcutaneous transplantation in nude mice. The model of colitis-associated colorectal cancer (CACC) was established with BALB/c mice. BALB/c mice were randomly divided into the normal control group, the model control group, and the FLCWK group. At the end of the administration, the pathological status was detected by HE staining. Cell apoptosis of tumor tissue tumor and colon tissues were observed by TUNEL staining and TUNEL green fluorescence. The protein expression of Caspase 3, p-STAT3, Bcl-2, Bax and P-gp in tumor tissues tumor and colon tissues were tested by using immunohistochemical assay. Results: FLCWK and 5-FU coadministration suppressed HT-29 cell viability and induced S phase arrest and apoptosis compared to treatment with 5-FU alone. Furthermore, compared to treatment with 5-FU alone, coadministration of FLCWK and 5-FU obviously reduced tumor volume and weight and induced apoptosis through decreasing p-STAT3 and P-gp and increasing Caspase 3 protein expression in a murine xenograft tumor model. Moreover, the result revealed decreased number and size of tumors following FLCWK protective administration, downregulated p-STAT3 and Bcl-2 levels and upregulated Bax and Caspase 3 expression in mice with CACC. Conclusions: FLCWK has synergistic effects with 5-FU on colorectal cancer by suppressing the STAT3 pathway and downregulating P-gp expression. Furthermore, FLCWK administration suppresses CACC tumorigenesis by inhibiting the STAT3 pathway.
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FUEL PROCESSING TECHNOLOGY
·
2019
·
IF 4.507
Qingfeng Che,Minjiao Yang,Xianhua Wang,Xu Chen,Wei Chen,Qing Yang,Haiping Yang,Hanping Chen
Dual catalysts are proposed in this study to convert biomass pyrolysis vapors into aromatics. Metal oxides (CaO, Al 2 O 3 , and ZnO) and ZSM-5 were introduced into the catalytic upgrading process. In the pyrolysis process without ZSM-5, the addition of CaO effectively removed carboxylic organics and methoxyphenols, reducing the product yield with a hydrogen to carbon ratio of 0, and the size of phenol compounds. The addition of Al 2 O 3 greatly promoted the cracking of oxygenates with molecular weight above 109 g mol −1 , such as large-size methoxyphenols and sugars. It is found that the upgraded pyrolysis volatiles are more conducive to conversion for aromatics with a ZSM-5 catalyst. The addition of CaO increased the selectivity of xylene (15.9%), while Al 2 O 3 promoted the selectivity of toluene (18.3%). The highest yield of aromatics was obtained with CaO-ZSM-5 dual catalyst system, which was boosted by 6.14% compared to that of pure ZSM-5. To explore more effective methods for aromatics production, the arrangement of catalysts and temperature condition were investigated. Mixing CaO with biomass produced more aromatics than other methods, and the most suitable temperature for the formation of aromatic hydrocarbons was 600 °C.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Xiaoxiao Sun,Chao Liu,A.M. Omer,Wuhuan Lu,Shuxing Zhang,Xun Jiang,Hongjie Wu,Di Yu,Xiao-kun Ouyang
To develop relatively green and ecofriendly smart vehicles for colon-specific drug delivery, carboxymethyl cellulose (CMC) and chitosan (CS) pH-sensitive biopolymers were used in this study. To overcome the weaknesses of CMC carriers, such as poor mechanical performance and an explosive drug release, zinc oxide (ZnO) nanoparticles were incorporated into CMC beads and then coated with a CS layer via a self-assembly technique to form core–shell polyelectrolyte complexes. An anticancer drug, 5-fluorouracil (5-FU), used as a model drug, was loaded into ZnO/CMC/CS bio-nanocomposite beads. Fourier transform infrared spectroscopy , scanning and transmission electron microscopy , and thermogravimetric analysis were used to characterize the chemical structure, morphological changes, and thermal properties of the developed drug carrier, respectively. By studying their swelling and in vitro 5-FU release profiles under simulated gastrointestinal conditions, the pH sensitivity of the developed bio-nanocomposite hydrogel beads could be investigated. The obtained beads with reduced porosity could effectively encapsulate 5-FU and showed self-sustained release behavior depending on the concentrations of CMC, CS, and ZnO nanoparticles. The developed beads also demonstrated a capacity for biodegradation. The results indicated that the ZnO/CMC/CS bio-nanocomposite beads exhibited pH-sensitivity and could be applied efficiently as biodegradable carriers for colon-specific 5-FU delivery.
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高影响因子
FUEL PROCESSING TECHNOLOGY
·
2019
·
IF 4.507
Siquan Xu,Donghui Pan,Feng Hu,Yuanfeng Wu,Huazheng Wang,Yuan Chen,Hui Yuan,Lijing Gao,Guomin Xiao
In the presented work, a series of Cr/β zeolites were prepared and used as bifunctional catalysts with Brønsted and Lewis acidity in the conversion of biomass-derived carbohydrates to 5‑hydroxymethylfurfural (HMF). The physicochemical properties of all catalysts were characterized by ICP-AES, N 2 physisorption , solid-state 27 Al NMR, XRD, SEM-EDX, UV–Vis, XPS , Raman, NH 3 -TPD and Py-FTIR techniques. It was found that the catalysts with appropriate total acidity, ratio of Lewis to Brønsted acid sites and acid density appear to be beneficial for HMF formation. Under mild reaction conditions, a superior 72% HMF yield with 83% selectivity was achieved from glucose in the H 2 O/THF biphasic system by using the 0.4-Cr/β zeolite catalyst. Moreover, the results of the stability evaluation showed that the catalytic activity of the 0.4-Cr/β zeolite was not significantly lost after four consecutive cycles, and the framework remained intact. Therefore, the catalytic approach proposed in this study is believed to provide potential prospects for the production of HMF from biomass material refining in the future.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Fuxiang Feng,Li Wang,Xiangwen Zhang,Qingfa Wang
Ultrathin Ni/ZSM-5 nanosheet catalysts with different acid concentrations, B/L (Brønsted/Lewis acid sites) ratios, and nanosheet thicknesses are designed for the hydroconversion of oleic acid into aviation-fuel-range alkanes (AFRAs). The role of acid concentration/distribution and nanosheet thickness was investigated. High acid concentration enhances the hydrodeoxygenation (HDO) reaction and intrinsic deoxygenation activity because of the synergistic effect between acid sites and metal sites. The selective cracking reaction can be enhanced by tailoring nanosheet thickness and acid distribution. The thin nanosheet favors isomerization, the selective cracking reaction, as well as the generation of central branched isomers. External acid sites dominate the primary cracking and central C–C cracking of the deoxygenated products, but internal acid sites promote the deeper cracking and terminal C–C cracking. Formation of aromatics is thoroughly suppressed at low reaction temperature (≤533 K). A high AFRA yield of 41.4% is achieved over the 3 nm nanosheet catalyst with Si/Al = 300 and B/L = 0.18.
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危险品化学品经营许可证（带存储）