INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
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IF 4.784
Xiaoxiao Sun,Chao Liu,A.M. Omer,Li-Ye Yang,Xiao-kun Ouyang
A new pH-sensitive drug carrier based on alginate (Alg), chitosan (Cs), and kappa-carrageenan (kC) marine biopolymers was developed, comprising a dual-layered polyelectrolyte complexes microbead structure. Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to investigate the structures, thermal stability , and morphological changes, respectively, of the microcapsules we developed. In the intestinal environment (pH 7.4), the stability and swelling of Alg microbeads were enhanced after generation of the dual-layered polyelectrolyte complexes. The in vitro release profiles of 5-fluorouracil under simulated GI conditions were also examined. At gastric pH (1.2), the cumulative 5-FU release percentage was decreased by introduction of the additional kC layer from 14% in Alg/Cs microbeads to 7% in the dual-layered Alg/Cs/kC microbeads. Additionally, the release profiles were greatly improved under simulated intestinal and colon conditions. Finally, the microbeads were all biodegradable and showed no cytotoxicity in Chang liver cells. Our results clearly indicate that the dual-layer pH-sensitive Alg/Cs/kC microbeads could be used effectively for the targeted delivery of anticancer drugs to the colon.
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ENERGY & FUELS
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2019
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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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INORGANIC CHEMISTRY
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2018
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IF 4.7
Yibao Chen,Maxim S. Molokeev,Victor V. Atuchin,Ali H. Reshak,Sushil Auluck,Zeyad A. Alahmed,Zhiguo Xia
Exploring new perovskite-related solid-state materials and the investigating composition-dependent structural and physical properties are highly important for advanced functional material development. Herein, we present the successful hydrothermal synthesis of tetragonal CsPb2Cl5 and the anion-exchange phase formation of CsPb2(Cl1–xBrx)5 (x = 0–1) solid solutions. The CsPb2(Cl1–xBrx)5 crystal structures, which crystallize in the tetragonal system, space group I4/mcm, with parameters similar to those of CsPb2Cl5, have been determined by Rietveld analysis. The optical band gap was obtained by UV–vis spectroscopy, and the band structure was further calculated by the full-potential method within the generalized gradient approximation. It was revealed that the band gap in CsPb2(Cl1–xBrx)5 solid solutions can be tuned over the range of 4.5–3.8 eV by anion substitution.
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ANALYTICA CHIMICA ACTA
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2018
·
IF 5.123
Shi-Fan Xue,Jing-Fei Zhang,Zi-Han Chen,Xin-Yue Han,Min Zhang,Guoyue Shi
A novel type of stimuli-responsive fluorescent polymers has been developed via the self-assembly of riboflavin-5′-phosphate (RiP) as ligand and europium (III) (Eu 3+ ) as central metal ion coordinated with the ligand. The as-prepared RiP/Eu 3+ coordination polymers (RiP/Eu 3+ CPs) are smart and multifunctional for respectively responding to chemical and physical stimuli, in which RiP acts as the stimuli-responsive fluorescent signal indicator. For sensing chemical stimuli, 2,6-pyridinedicarboxylic acid (DPA, an anthrax biomarker) having higher bonding force towards Eu 3+ can grab it from smart RiP/Eu 3+ CPs through competition reaction, resulting in the release of RiP for highly sensitive and selective DPA monitoring in a mix-and-read fluorescent enhancement format, and the detection limit is as low as 41.5 nM. Density functional theory (DFT) calculations has been also performed to verify the DPA sensing principle. For sensing physical stimuli, the smart RiP/Eu 3+ CPs can be acting as a novel sensory probe for the determination of temperature from 10 °C to 40 °C based on the thermal-induced disruption of the binding between Eu 3+ and RiP and the disassembly of the smart RiP/Eu 3+ CPs accompanying with the recovery of the fluorescence of RiP. This work establishes an effective platform for multifunctional sensing of chemical and physical stimuli utilizing both smart lanthanide nanoscale coordination polymers (LNCPs) and novel sensing strategies.
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TALANTA
·
2018
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IF 4.244
JingHong Li,Nan Chen,YiPing Tian,Hui Xu
The exploration of volatile organic compounds (VOCs) produced by cell lines may be a powerful and non-invasive tool for the study of the health risk of human exposure to atmospheric particulate matter (PM). In this work, we developed a sensitive solid phase microextraction-gas chromatography-mass spectrometry method (SPME-GC-MS) to analyze VOCs in breathed gas of PM2.5-induced human embryonic fibroblast cell line (MRC-5). A novel graphene oxide/polyaniline/polydopamine (GO/PANI/PDA) coating was prepared on a stainless steel wire via electrochemical deposition and self-polymerization for the first time. The GO/PANI/PDA coating exhibited high extraction efficiency, good thermal stability (> 380 ℃), excellent mechanical stability as well as long service time (> 150 times). Parameters that may affect the results were optimized systematically. Under the optimal conditions, VOCs including benzene series, aldehydes and alkane were detected with low limit of detection (0.2–2.0 μg L −1 ) and good correlation (correlation coefficients above 0.9922). The relative standard deviations of within-day and between-day were 1.1–8.4% and 0.2–11.2%, respectively. Satisfactory recoveries of 82–117% indicated good repeatability of the method. The method has been successfully applied for the determination of target VOCs in the headspace gas of PM2.5-induced MRC-5 cell. And it is expected to provide an alternative tool for the study of cytotoxicology of atmospheric particulates.
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FUEL
·
2018
·
IF 4.908
Tao Chen,Lincai Peng,Xin Yu,Liang He
A series of carbonaceous solid acid catalysts were prepared by facile carbonization and sulfonation of biorenewable feedstocks (i.e., glucose, sucrose, starch and cellulose), and employed for directly converting carbohydrates in ethanol medium to synthesize 5-ethoxymethylfurfural (EMF). The carbonization temperature of cellulose and starch (500 °C) was required to be higher than that of glucose and sucrose (400 °C) to realize high –SO 3 H density and EMF yield. Based on rich exploitability of cellulose and good activity of its derived carbonaceous catalyst, magnetic cellulose-derived carbonaceous solid acid (MCC-SO 3 H) was subsequently synthesized, which possessed a porous structure with BET surface area of 35.34 m 2 g –1 , high –SO 3 H density (1.28 mmol g –1 ) and sufficient magnetism for separation (1.99 emu g –1 ). By optimizing the process variables, a maximum EMF yield of 63.2% could be achieved from fructose at 120 °C, and ethyl levulinate formation was favored at elevated temperature. The MCC-SO 3 H catalyst could be readily separated from the reaction mixture by an external magnet with recovery rate of 92.6% after six successive runs, and reused repeatedly with little deactivation. Besides, this catalyst was efficient for the one-pot transformation of fructose-based polysaccharides into EMF, affording yields of 51.3% and 32.5% from inulin and sucrose, respectively. With glucose as the substrate, instead ethyl glucoside with a high yield of 86.5% was obtained.
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Journal of Chemistry
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2018
·
IF 1.726
Zou Bin,Chen Xueshan,Xia Jiaojiao,Zhou Cunshan
Conversion of HMF into FDCA was carried out by a simple and green process based on alkaline ionic liquid (IL) modified Pd/C catalyst (Pd/C-OH−). Alkaline ionic liquids were chosen to optimize Pd/C catalyst for special hydrophilicity and hydrophobicity, redox stability, and unique dissolving abilities for polar compounds. The Pd/C-OH− catalyst was successfully prepared and characterized by SEM, XRD, TG, FT-IR, and CO2-TPD technologies. Loading of alkaline ionic liquid on the surface of Pd/C was 2.54 mmol·g−1. The catalyst showed excellent catalytic activity in the HMF oxidation after optimization of reaction temperature, reaction time, catalyst amount, and solvent. Supported alkaline ionic liquid (IL) could be a substitute and promotion for homogeneous base (NaOH). Under optimal reaction conditions, high HMF conversion of 100% and FDCA yield of 82.39% were achieved over Pd/C-OH− catalyst in water at 373 K for 24 h.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2018
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IF 3.779
Yuanyuan Fu,Yanfei Li,Rihui Zhou,Yuzhe Zhang,Shouhui Chen,Yonghai Song,Li Wang
A new route to load Co 3 O 4 nanoparticles (NPs) on MOF-5 (MOF-5 was composed of 1,4-benzenedicarboxylate (BDC) and Zn 2+ via coordination bond (Zn 4 O(BDC) 3 ·(DMF) 8 (C 6 H 5 Cl)), where MOF indicates metal-organic framework) derived hierarchically porous carbon (MDPC) was proposed. Various techniques including scanning electron microscopy, transmission electron microscopy , Raman spectroscopy , powder X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis and electrochemical methods were used to characterize the Co 3 O 4 NPs@MDPC. The results showed that the MDPC contained mesopores obtained by vaporizing ZnONPs and micropores came from MOF-5 self. Lots of nano-sized Co 3 O 4 NPs formed in MDPC's mesopores. The vast micropores of MDPC provided an effective channel for the transport of Li + when it was used as anode materials for lithium ion batteries (LIBs). The MDPC prevented Co 3 O 4 NPs from agglomerating effectively, which remained robust for superior rate capability during repeated lithiation/delithiation process. And the as-prepared Co 3 O 4 NPs@MDPC composites remained 94% reversible capacity from the second cycle. Furthermore, the as-prepared Co 3 O 4 NPs@MDPC anode manifested outstanding capability of 587.2 mA h g -1 at 2000 mA g −1 after 200 cycles, apparently superior to that of other Co 3 O 4 NPs@PC. The high capacity especially at high current density and exceptional rate capability of Co 3 O 4 NPs@MDPC manifested it is a promising anode material for LIBs.
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KOREAN JOURNAL OF CHEMICAL ENGINEERING
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2018
·Vol. 35
·期 6
·1312-1318
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IF 2.199
Xiong Caixia,Sun Yong,Du Juan,Chen Wei,Si Zhihao,Gao He,Tang Xing,Zeng Xianhai
5-[(Formyloxy)methyl]furfural (FMF), an analogue of 5-(hydroxymethyl)furfural (HMF) is becoming more attractive due to its superior stability and hydrophobicity, which make it easier to refineand store. In the present study, FMF was produced from fructose by one-pot approach in pure formic acid media or by a two-step approach via HMF in choline chloride (ChCl)/fructose deep eutectic solvents (DES) system. A favorable FMF yield of 63.22% was reached by two-step approach. In addition, the effects of reaction parameters, such as temperature and acidity, on preparation of FMF from fructose were systematically investigated. The dehydration of fructose into HMF was confirmed as the rate-controlling step in the consecutive reaction. Ultimately, the separation and purification procedures of FMF were put forward. The FMF with a purity of 98.8% was obtained finally. Meanwhile, the FMF purified by saturated sodium bicarbonate solution showed an excelled storage stability.
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CATALYSIS TODAY
·
2018
·
IF 4.667
Mengke Liu,Yingnan Zhao,Huawang Zhao,Xianghui Li,Yuhan Ma,Xin Yong,Hong Chen,Yongdan Li
A number of M-Cu-ZSM-5 (M = La, Ni, La-Ni) samples were prepared via an aqueous solution ion-exchange method. The co-doping with Ni and La into a Cu-ZSM-5 catalyst enhanced the NO decomposition activity in a temperature range 350–550 °C. The characterization results indicate that doping with La effectively improved the dispersion of the Cu species forming more Cu 2+ ions in the sample, while the effect of Ni is likely to facilitate the implantation of Cu 2+ to form (Cu 2+ -O 2– -Cu 2+ ) 2+ dimers. The synergistic effect of La and Ni contributes to the increased (Cu 2+ -O 2− -Cu 2+ ) 2+ content in the co-doped sample, thus enhancing the NO decomposition activity.
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RSC Advances
·
2018
·Vol. 8
·期 5
·2561-2574
·
IF 2.936
Yan Yan,Jinyao Sun,Xianting Xie,Pengchong Wang,Ying Sun,Yalin Dong,Jianfeng Xing
The aim of this study was to design and synthesize four colon-targeting mutual prodrugs of 5-aminosalicylic acid (5-ASA) and butyrate, and evaluate their therapeutic effects on ulcerative colitis. Herein, 5-ASB, 5-ASDB, Ols-DB and Ols-DBP were prepared and characterized, and their lipophilicity, solubility, in vitro and in vivo stability were investigated. Finally, the ameliorative effects of the prodrugs on experimental colitis were evaluated via a series of indicators, including the body weight and survival rates of mice, the colon index and colonic damage score, the disease activity index, the myeloperoxidase activity and levels of superoxide dismutase, malondialdehyde, glutathione and glutathione peroxidase in colonic tissues. As a result, 5-ASB was very stable but Ols-DB showed extreme instability in the environment of the gastrointestinal tract, while 5-ASDB and Ols-DBP showed desirable colon-targeting properties. The four prodrugs all had certain therapeutic effects on the experimental colitis. When orally administered to mice, 5-ASDB and Ols-DBP had significantly greater effects than the mixture of 5-ASA and sodium butyrate. Ols-DB was used as an enema and could be as effective as 5-ASDB and Ols-DBP. In addition, the therapeutic effects of the synthesized prodrugs might be associated with their anti-oxidative damage ability.
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CRYSTENGCOMM
·
2017
·Vol. 19
·期 47
·7088-7094
·
IF 3.474
Baoliang Peng,Houbing Zou,Lipeng He,Pingmei Wang,Zhiqiang Shi,Liangkui Zhu,Runwei Wang,Zongtao Zhang
Hierarchical zeolites are promising solid acid catalysts for industrial processes and conversions of bulky molecules because they provide fast mass transfer along with size and shape selectivity; however, their synthesis always involves either complicated post-synthetic modifications or cost-intensive templates. In this work, engineering growth defects has been developed as a new and efficient strategy for preparing hierarchical ZSM-5 zeolite with high specific surface area and abundant uniform intracrystalline mesopores. This route only involved certain energy-efficient conditions, e.g., tender crystallization and mesotemplate-free conditions. Combining tender crystallization conditions with an optimal original Si/Al ratio (150–300) in a colloid synthesis system was found to be the key to successfully engineer the growth defects. Importantly, it even exhibited higher catalytic activities for benzaldehyde–alcohol condensation reactions than mesoporous ZSM-5 zeolite prepared using mesoscale templates.
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