We proposed a green microwave-assisted hydrothermal way to synthesize highly crystalized N-doped carbon quantum dots(N-CQDs). The N-CQDs obtained by this microwave method have good crystalline degree(ID/IG=0.6) and a high molar ratio of N/C(11.1%) comparing with those obtained from traditional top-down method. The experimental results show that glycerine plays a key role in the formation of highly crystalized N-CQDs. The as-prepared N-CQDs have good luminescent property and may be utilized as fluorescent probe to detect ions or mark cells. As the majority of N atoms in the N-CQDs were pyridinic type(64.8%), the as-prepared N-CQDs were used as a catalyst for the oxygen reduction reaction(ORR) electrocatalysis in the anode of the fuel cell(the onset potential is -0.121 V), which was a 4e-transfer procedure and the catalyst showed good stability after 100 cycles.
We used the one-step hydrothermal controlled synthesis method for Co-Ni3S2 ultrathin nanosheets grown directly on nickel foam(NF). The as-synthesized Co-Ni3S2/NF showed enhanced activities in the hydrogen evolution reaction(HER), oxygen evolution reaction(OER) and better overall water splitting(OWS) efficiency than the un-doped Ni3S2/NF. The voltage of Co-Ni3S2/NF for OWS was only 1.58 V at the current density of 10 mA/cm2 and with long time(>30 h) current output during the current-density(i-t) test. The good i-t performance was also observed in both HER and OER processes. Additionally, the Co-Ni3S2/NF showed a large current density(>1 A/cm2) for both HER and OER. When the current densities reached 100 and 1000 mA/cm2, the required overpotentials for Co-Ni3S2/NF were 0.35 and 0.75 V for OER and 0.30 and 0.85 V for HER. Therefore, after introducing Co, the activity of Ni3S2-based material was strongly enhanced.
Although protein tyrosine phosphatases(PTPs) do not contain any metals, their activities can be inhibited by some metal complexes. Here we investigated the inhibition of two zinc complexes with Schiff base ligands against PTPs activity to explore their effect on the cellular metabolism. It has been found that they are potent inhibitors against four recombinant PTPs, including protein tyrosine phosphatase 1B(PTP1B), T cell protein tyrosine phosphatase(TCPTP), megakaryocyte protein tyrosine phosphatase 2(PTP-MEG2), and Src-homology phosphatase 1(SHP-1), with exception of Src-homology phosphatase 2(SHP-2). Moreover, they showed moderate selective inhibition against PTP1B with the IC50 values of 0.15 and 0.36 μmol/L. Meanwhile, the complexes also inhibited cellular phosphatase activities efficiently. Comparing the inhibitory potency over PTPs mediated by the zinc ion, we found that zinc complexes might be easily developed into potent and selective inhibitors against certain PTP by rationally modifying the organic ligands moieties.
We herein report the development of a bromophenol blue(BPB)-silicone composite film/K+-exchange glass optical waveguide(OWG) sensor for the detection of amines produced during the spoilage of lamb. The optical and structural properties of the sensitive thin film were studied by ultraviolet-visible(UV-Vis) spectroscopy, and the light source of the OWG detecting system was selected. Gas sensing measurements showed that the sensor exhibited a good selectivity, high sensitivity, and short response-recovery time towards volatile amine gases in the 0.00117-11.72 mg/g range. The as-prepared optical waveguide device was subsequently applied in the determination of gases (namely trimethylamine, dimethylamine, and ammonia) emitted from the lamb samples(5 g) stored at room temperature(25℃) and in a refrigerator(5℃) for 0-4 d, and the total volatile basic nitrogen(TVB-N) contents were detected by UV-Vis spectroscopy, and the results were compared with those obtained using our detector. It was found that the sensing element was capable of detecting mixed gases produced by the decomposition of lamb samples in a refrigerator for 0.5 h, where the TVB-N content was lower than 35 μg/g.
Two new compounds, 4-(2-bromophenyl-4,5-diphenyl-imidazol-1-yl)aniline(probe 1) and 4-[2,4,5-tris(4-bromophenyl)-1H-imidazol-1-yl]aniline(probe 2), were synthesized via a soft and high-efficiency one-pot microwave-assisted method under solvent-free conditions. Their sensing to different metal ions was detected by UV spectrophotometry and fluorescence spectrometry. Probe 2 revealed highly selective and sensitive UV and fluorescence response to Fe3+ ion. Upon the addition of Fe3+ ion, probe 2 showed obvious color change of the solution, conspicuous absorbance enhancement and relatively quick fluorescence quenching. The detection limit for Fe3+ ion was respectively calculated to be 0.72 μmol/L(fluorescent detection) and 0.48 μmol/L(UV-spectrum detection). Also, probe 2 was bound by Fe3+ ion to form a 1:1 complex. Moreover, preliminary application of probe 2 for detecting Fe3+ ion in aqueous solution was attempted, and satisfying results were obtained.
A green and sensitive sample separation and purification method coupled with high-performance liquid chromatography(HPLC) was developed for the analysis of chloramphenicol(CAP). One element small molecule alcohol-salt aqueous two-phase system(ATPS) can't effectively adjust the polarity of the system, but binary small molecule alcohol-salt ATPS can adjust the polarity and improve the extraction efficiency of antibiotics. A binary aqueous two-phase system based on 1-propanol+2-propanol and NaH2PO4 system was formed and applied to the separation and purification of trace CAP in real samples. The influence factors on partition behaviors of CAP were discussed, including the types and mass of salts, the volume ratio of alcohol, the pH, temperature and the standing time. The optimal condition was found at pH=5.0, 2.5 g of NaH2PO4, 3.0 mL of 1-propanol and 2-propanol(volume ratio 1:1) and 30℃ by using response surface methodology. Under this optimal condition, the extraction efficiency of CAP reached 98.91%, and partition coefficient of CAP was 17.31.
A straightforward and efficient synthetic method of 2'-(dialkylamino)-1-alkyl-4'H-spiro[indoline-3,5'-oxazole]-2,4'-diones and 2-(dialkylamino)-5,6-dihydro-4H-naphtho[2,1-e] [1,3]oxazin-4-one derivatives have been developed from α-hydroxy and β-carbonyl amides and various Vilsmeier salts. A wide range of heterocyclic compounds were obtained in excellent yields(up to 97%), which will provide promising candidates for chemical biology and drug discovery.
We synthesized nine novel triazole-compounds and investigated their plant growth regulatory activity. Compound CGR3, with methoxyacyl on 3-position of triazole ring, showed better activity, promoting root length not only for mungbean, but also for wheat. Additionally, CGR3 changed the level of endogenous hormones in mungbean roots, the most obvious effect was the increase of IAA, being 4.9 times greater than that of the control at the 96th hour after treatment. Among the synthesized new 1,2,4-triazol derivatives, CGR3 could be applied as a new agrochemical, functioning as a root growth stimulant, which promotes primary root length, influences the levels of endogenous hormones(IAA, ABA and GA3) to play an important role in controlling the primary root development.
By utilizing terpyridine-bridged parallel metallo-complexes as dication metallo-bisviologens, herein we present the synthesis and characterization of two novel supramolecular complexes. 1-Methylpyridin-1-ium-terpyridine ligands and their metallo-complexes were first designed and synthesized, and the association of methylpyridiniums with dibenzo-24-crown-8 ether(DB24C8) afforded the desired novel complexes through host-guest interactions. The self-assembly behavior of the supramolecular complexes was comprehensively investigated and could be exploited for further construction of 1D to 3D supramolecular infrastructures.
A series of highly functionalized 1,4-dihydropyridines was synthesized via one-pot multicomponent reactions of aromatic aldehyde, malononitrile and N-methyl-1-(methylthio)-2-nitroethenamine using Porcine pancreatic lipase(PPL) as catalyst in DMSO. This protocol is featured by mild reaction conditions, simple operation and environmental acceptability.
In this study, we constructed the recombinant plasmid of pGL2/Aquaporin5(AQP5) promoter (pGL2/AQP5p) luciferase reporter, then found estradiol(E2) induced AQP5 promoter activation in a dose-dependent manner. Further, we identified endogenous estrogen receptors(ER), including ERα and ERβ, expressed in human submandibular gland(HSG) cells, which responded to E2. Then demonstrated by the stimulation of E2, AQP5 was upregulated in protein level, meanwhile AQP5 located in cytomembrane was elevated in immunofluorescence. Furthermore, we revealed the roles of ERα and ERβ in AQP5 upregulation by E2. When ERα and ERβ were over-expressed, the AQP5 transcription level and protein expression were augmented obviously. While when knockdown ER by ERα-shRNA or ERβ-shRNA, AQP5 transcription and expression attenuated. Moreover, we detected the effect of E2 in Sjogren's syndrome(SS) mice model in vivo. SS mice models were constructed by injecting submandibular gland antigen immune induction combined with estrogen deprivation, which were administrated with saline and E2. The salivary secretion was decreased, and the AQP5 expression downregulated in the submandibular gland in the SS model group. When SS mice were administrated with E2, the salivary secretion was significantly increased, and the AQP5 expression upregulated in the submandibular gland. These results suggest E2 activates AQP5p transcription and upregulates AQP5 protein expression, and E2 promotes salivary secretion in SS model in vivo. Taken together, we provided the evidence that E2 increased salivary secretion by activating AQP5 transcription and expression.
Alzheimer's disease(AD) is a neurodegenerative disorder characterized by the deposition of β-amyloid peptide(Aβ) in the brain tissues, and an imbalance in the oxidant-antioxidant system. Compounds with antioxidant activity and the ability to inhibit Aβ aggregation therefore potentially treat AD. In this study, we designed an iron-porphyrin containing bifunctional peptide(BP, Deuterohemin-AlaHisThrValGluLysLeuProPhePheAsp) based on natural microperoxidase-11(MP-11) and typical β-sheet breaker LPFFD(iAβ5p). This BP substantially reduced the aggregation of Aβ and caused oligomer disassembly, by binding Aβ with affinity constant of 9.07 μmol/L. Furthermore, it showed a neuroprotective effect on Aβ25-35 induced toxicity in SH-SY5Y cells, and significantly alleviated Aβ-induced paralysis and extended lifespan in Aβ1-42 transgenic C. elegans(CL4176). It also showed a potent peroxidase activity of 20.8 U/mg, and scavenged free radicals both in vitro and in vivo. In addition, BP up-regulated the levels of hsp16.2, hsp16.41, and hsp12.6 mRNAs to 183.26%, 160.16%, and 162.64% respectively, and down-regulated that of hsp70 to 36.76% in C. elegans. Taken together, the synthetic BP inhibited Aβ aggregation and showed antioxidant activity, indicating the therapeutic potential of novel peptide drugs against AD.
A facile co-precipitation method was developed to prepare the novel metalloporphyrins-Ba2+ composites with ca. 3 μm diameter and olive-like morphology. Olefins epoxidation reactions were employed to investigate their catalytic performance. Compared with the free metalloporphyrins, the composites exhibited not only the improved stability and recyclability, but also the enhanced catalytic activity. Such catalytic behaviors could be related to the unique structure of the composites, e.g., the strong interaction between R-SO3- and Ba2+ ions and the uniform distribution of metalloporphyrins on the catalyst surface, respectively. Furthermore, the composites showed good compatibility with a wide range of substrates. The well-designed composites are expected to be efficient catalysts, alternative to many sophisticated-synthesized metalloporphrins-based materials, in the industrially important reactions.
A novel heterogeneous catalyst, amorphous Cu0 on the carbon nanofibers was developed and characterized by means of several characterization techniques. The prepared Cu0 was investigated as a heterogeneous catalyst for N-arylation reaction. The results show it is an excellent catalyst with recyclability, high consistency and catalytic activity. After the catalyst was used for 5 cycles in the N-arylation reaction, amorphous Cu0 reunited into crystalline copper nanoparticles with different particle sizes and its good heterogeneity in the catalytic system was confirmed after the catalyst recovery.
A facile and green freeze-drying-assisted method was proposed to synthesize CoMoO4 mesoporous nanosheets(MPNSs). The resulting product exhibits a high specific capacity and good rate performance when evaluated as an anode material for lithium-ion batteries(LIBs). The reversible specific capacity can be kept at 1105.2 mA·h·g-1 after 100 cycles at a current density of 0.2 A/g. Even at the current densities of 1 and 4 A/g, the CoMoO4 MPNSs electrode can still retain the reversible capacities of 1148.7 and 540 mA·h·g-1, respectively. Furthermore, the full cell(LiFePO4 cathode/CoMoO4 MPNSs anode) displays a stable discharge capacity of 146.7 mA·h·g-1 at 0.1 C (1 C=170 mA/g) together with an initial coulombic efficiency of 98.2%. In addition, the CoMoO4 crystal structure is destroyed and reduced into Co0 and Mo0 in the first discharge process. In the subsequent cycles, the attractive Li storage properties come from the reversible conversions between Co/Co2+ and Mo/Mo6+. The improved electroche-mical performance of CoMoO4 MPNSs is mainly attributed to their unique porous structures, which not only possess a good ion diffusion and electronic conduction pathway, but also provide many cavities to alleviate the volume changes during repeated cycling. This work offers a new perspective to the design of other porous electrode materials with a good energy storage performance.
ZnO nanoparticles(NPs) with different contents of Ag dopants were obtained by one-step solvothermal method. The crystalline structures of the prepared composites were characterized by means of X-ray diffraction (XRD). The morphology and composition of the samples were studied by means of scanning transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS) and electron microscopy(SEM). Photoluminescence(PL) spectra have been used to investigate pure ZnO, Ag-ZnO and Ag-ZnO-PVP NPs to determine the effect of composition on PL properties. It was found that the Ag-ZnO samples showed stronger emissions than pure ZnO. The catalytic activity of samples was measured by the degradation rate of R6G, which exhibited that Ag-ZnO nanocomposite demonstrated enhanced photocatalytic activity compared to the pure ZnO NPs. The possible influence factors to the photocatalytic and antibacterial activities of the sample were explored, including Ag contents and dispersion. It was presented that the photocatalytic activity of Ag-ZnO-PVP was better than that of Ag-ZnO and it showed the highest photocatalytic activity with 7% of Ag content. The Ag-ZnO-PVP can kill the Escherichia coli(E. coli) cells.
A series of BiOClxI1-x(x=0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0) photocatalysts was firstly prepared by means of a facile solvothermal route with the help of lactic acid. The measured results show that the morphologies of the as-prepared samples are similar sheets with different thickness and diameters. Thinner nanosheets assembled flower-like BiOCl0.5I0.5 solid solution exhibited the highest photocatalytic activity and stability among the prepared samples for the degradation of methylene blue(MB) and methyl orange(MO) under the illumination of visible light. The excellent photocatalytic properties of BiOCl0.5I0.5 could be attributed to the high specific surface area, the suitable band gap energy and the lower recombination rate of the electrons and holes. In addition, catalyst BiOCl0.5I0.5 was further used to degradate a more complicated mixed dye (MO+RhB+MB) system under visible light, displaying an excellent photocatalytic activity. Finally, the photocatalytic mechanism of catalyst BiOCl0.5I0.5 to degradate colorful dyes was proposed. The trapping experiments of active species indicated that the holes are the main active species for the degradation of the mixed dyes.
The bio-oil derived from pyrolysis of straw can be selectively converted into high-purity hydrogen by coupling three steps:(i) steam reforming(SR) of different bio-oils, (ii) water-gas shift(WGS), and (iii) the removal of CO2. The catalytic SR reaction over the NiLaTiAl catalyst, coupled with a low-temperature WGS reaction with the CuZnAl catalyst, promoted the conversion of various oxygen-containing organic compounds in the bio-oil into hydrogen and carbon dioxide. Under the optimized condition, light bio-oil achieved the highest conversion(99.8%, molar fraction), with a high hydrogen yield of 16.4%(mass fraction) and a H2 purity of 99.94%(volume fraction). The carbon deposition on the NiLaTiAl catalyst was the main factor caused catalyst deactivation. Production of hydrogen from different bio-oil model compounds was also investigated in detail.
This work aimed to investigate the distinct electrochemical performance and microbial flora of microbial fuel cells(MFCs) in relation to different single hazardous fed fuels. Three replicate MFCs were inoculated with the same microbial consortium from a coking wastewater treatment plant, wherein ammonium chloride(ammonium chloride-fed MFC, N-MFC), phenol(phenol-fed MFC, P-MFC) and potassium sulphide(potassium sulphide-fed MFC, S-MFC) were the sole substrates and main components of real coking wastewater. With initial concentrations of ammonium chloride, phenol and potassium sulphide of 0.75, 0.60 and 0.55 g/L, the removal efficiencies reached 95.6%, 90.6% and 99.9%, respectively, whereas the peak output power densities totalled 697, 324 and 1215 mW/m2. Microbial community analysis showed that the respective addition of substrate substantially altered the microbial community structure of anode biofilm, resulting in changes in relative abundance and emergence of new strains and further affecting the electrochemical properties of MFCs. The chemical oxygen demand(COD) removal efficiency of real coking wastewater, in which the inoculum was the combined biomass from the three MFCs, reached 82.3%.
Densities of methyl nonanoate, n-dodecane, and their binary mixtures were investigated to provide the necessary data for their engineering applications as promising fuels and fuel additives. In the present work, densities were measured under atmospheric pressure at 293.15-463.15 K. The density data for the binary mixtures were fitted into a form of excess molar volume. The excess molar volumes were mostly positive, and the maximum value was obtained at molar fractions of n-dodecane between 0.5 and 0.6. Molecular simulations of specified systems were carried out by using four kinds of force fields, and the suitable force fields for describing the volume properties of the system were AMBER96 and OPLS-AA. The relative deviations for these two force fields between the simulated and the experimental data were well within ±4%, which meets the general engineering requirement.
The hierarchical porous Fe2O3 particles as a novel ultraviolet light assisted heterogeneous Fenton catalysts were synthesized by bio-template synthesis method using iron nitrate as precursor at high temperature of around 550℃. The hierarchical porous structured Fe2O3 was endowed with a large surface area and abundant pore volume, leading to the exposure of more active sites and rapid mass transfer. The synergistic effect of UV irradiation and hierarchical porous Fe2O3 improved the photo-degradation efficiency of Tetracycline(TC). The degradation efficiency of Fe2O3 catalyzing UV-Fenton system reached 97.4% after 60 min reaction, which was more substantial than Fe2O3 catalyzing Fenton system(7.6%) and UV/H2O2 system(59.2%). Moreover, the hierarchical porous Fe2O3 catalyzing UV-Fenton system exhibited an extremely wide pH range(from 3.0 to 9.0, from mildly acidic to slightly alkaline) for efficient degradation of TC. Simultaneously, the extraordinary higher degradation efficiency was based on 10 mmol/L H2O2 concentration, which was low requirement for H2O2. Further, the hierarchical porous Fe2O3 can be used for five consecutive cycles with over 95% of the original degradation efficiency. Ultraviolet light assisted heterogeneous Fenton reaction in the hierarchical porous Fe2O3 improved the ·OH and O2·- production and Fe(Ⅲ)/Fe(Ⅱ) redox cycle, which consequently achieved an excellent degradation rate.
The hydrophilic multi-walled carbon nanotube(MWCNT) hydrogel was prepared using acrylic acid, acrylamide and hydrophilic MWCNT. The orthogonal experiment was applied to optimize the synthetic conditions. The MWCNT hydrogel was characterized by Fourier transform infrared spectrophotometer(FTIR) and scanning electron microscopy(SEM) analysis. The MWCNT hydrogel was used as the adsorbent to adsorb water-soluble cationic dye. This study evaluated the adsorption performance of hydrogels on four dyes of safranine T, crystal violet, malachite green and methylene blue in water. The effects of the amount of hydrogel, the size of hydrogel, pH, and the temperature on the adsorption performance were investigated. The adsorption kinetic and adsorption isotherm curves were measured. The experimental results show that the MWCNT hydrogel can be easily separated from water and the adsorption capacity is much greater compared to the hydrogel without MWCNT. The MWCNT hydrogels can be used in wastewater treatment with a great potential.
Graphitic carbon nitride(g-C3N4) microspheres supported α-FeO(OH) hybrids[α-FeO(OH)/g-C3N4] were prepared by means of a self-assembly method in deionized water. By UV-visible diffuse reflectance spectroscopy, it has been confirmed that α-FeO(OH)/g-C3N4 has a wider absorption range than g-C3N4. The feature of α-FeO(OH)/g-C3N4 can be attributed to the efficient separation of the electron-hole pairs with photoluminescence spectra. The degradation rate of methyl orange(MO) is up to 99% under the optimal conditions of 110 min, initial concentration of 30 mg/L, an α-FeO(OH)/g-C3N4 dosage of 15 mg as well as visible light. The mechanism for this photocatalytic reaction was proposed, with hydroxyl radicals being a major active catalytic species.
Molecular docking was used to calculate the affinity energy between biphenyl dioxygenases(BphA), including 1ULJ, 1WQL, 2YFJ, 2YFL, 2GBX, 2XSH, 2E4P, 3GZX, and 3GZY(selected from the Protein Data Bank) and 209 polychlorinated biphenyl(PCB) congeners. The relationships between the calculated affinity energy and the persistent organic pollutant characteristics(migration, octanol-air partition coefficients, lgKOA; persistence, half-life, lgt1/2; toxicity, half-maximal inhibitory concentration, lgIC50; bioaccumulation, bioconcentration factor, lgBCF) of the PCBs were studied to understand the BphA mediated degradation of PCBs. The effect of substituent characteristics on the affinity energy was explored through full factorial experimental design. The affinities of nine kinds of BphA proteins on PCBs ranked as follows:2GBX > 2YFJ > 2YFL > 3GZX > 2XSH > 3GZY > 2E4P > 1WQL > 1ULJ. The relationships between the calculated affinity energy and the molecular weight, lgKOA, lgBCF, and lgt1/2 of the PCBs were statistically significant(p<0.01), whereas the relationship with the lgIC50 of PCBs was not statistically significant(p>0.05). PCBs were more difficult to degrade following an increase in the free energy of binding. Correlation analysis showed that the average affinity energy values of PCBs gradually increased as the number of chlorine atoms increased, regardless of the substituent position. The substituents at the ortho-positions interacted mainly through a second-order interaction, whereas those at the para-positions did not participate via a second-order interaction.
Density functional theory(DFT) was employed to calculate the geometrical structures, UV-Vis absorption spectra and second-order nonlinear optical(NLO) properties of a family of iridium(Ⅲ) complexes, which possess of different cyclometallated ligands(C^N) and ancillary ligands[pyridine-2-carboxylate(pic)]. It was found that the mo-dification of the LUMO energy levels was achieved by changing pic ligands and the energy gaps between the HOMO and LUMO were notably increased or decreased. In addition, the degree of conjugation was significantly changed with the substituent groups varied, which led to that the first hyperpolarizability β could be effectively modulated. Through the analysis of time-dependent DFT(TD-DFT) results, we predicted that these studied complexes with π→π* charge transfer was beneficial to the large second-order NLO properties. Therefore, we hope that these studied iridium(Ⅲ) complexes can be considered as versatile second-order NLO materials.
Poly(ethylene phosphonate) was synthesized via the living ring-opening polymerization of cyclic phosphonate monomer catalyzed by organocatalyst. The pendant vinyl functionalities were employed to perform the photochemical click reactions with thiols. We demonstrated that both small thiol molecules and macromolecular thiols could be efficiently coupled into the PPE side chains, enabling the rapid and efficient functionalization of polyphosphoesters(PPE).
To improve the mechanical properties of bio-based poly(ethylene succinate), the sugar monomer isosorbide, which is relatively easy to obtain, was used as a copolymerized third monomer to synthesize poly(ethylene-co-isosorbide succinate), a 100% biomass copolyester. The effects of isosorbide on the crystallinity and thermal properties of copolyester were studied by nuclear magnetic resonance(1H NMR), differential scanning calorimeter (DSC), and thermogravimetric(TG). Owing to its distinct rigid bicyclic structure, isosorbide can improve the glass transition temperature of the copolyester and decrease the crystallization rate, as well as accelerate the hydrolysis of the copolyester. Simultaneously, the introduction of isosorbide can effectively improve the antistatic properties of copolyester.
Enhancing the molecular loading capability of layer-by-layer(LbL) method holds high importance in environmental and biomedical application. Here, we reported a strategy to prepare highly loaded poly(acrylic acid)(PAA)/poly(allylamine hydrochloride)(PAH) LbL films by combining the particulate templating strategy and acid treatment film transformation and realized the efficient loading of hydrophilic small molecules. The loaded molecules can be released in a pH-controlled manner. A slow release speed was observed in the acidic solutions with pH value of 3. Abrupt releases were observed at higher pH values(5 or 7).