Multifunctional lanthanide metal-organic frameworks(MOFs), M(H4TCPS)(H2O)1.5[M=Tb(JUC-95a), Er(JUC-95b), Dy(JUC-95c), Tm(JUC-95d), Y(JUC-95e) and Pr(JUC-95f); H4TCPS=tetrakis(4-carboxyphenyl)silane]_were synthesized via the reaction of the lanthanide metal ions(Ln3) with a rigid silicon-centered tetrahedral carboxylate ligand H4TCPS via a hydrothermal synthesis method. X-Ray diffraction(XRD) analyses reveal that they are extremely similar in structure and crystallized in a monoclinic system with space group C2/c. Two eight-coordinated metal centers and four tetrahedral H4TCPS groups constructed a paddle-wheel building block. The paddle-wheel buil-ding blocks assembled with each other via one oxygen bridge from a water molecule to lead to a 1D infinite inorganic rod-shaped chain, −Y−O−C−O−Y−, along the [001] direction. These 1D inorganic rod-shaped chains linked with the phenyl groups of the tetrahedral H4TCPS ligand to form a 3D framework. In addition, the luminescent and magnetic properties of these compounds show that they could be potential antiferromagnetic and fluorescent materials.
Two new open-framework gallium phosphites formulated as (C2N2H10)0.5Ga2(OH)(H2O)(HPO3)3(1) and (C3N2H5)2(C3N2H6)Ga8(H2O)6(HPO3)14(2) were hydrothermally synthesized in the presence of ethylenediamine(en) and imidazole as structure directing agents(SDA), respectively. Structural analyses reveal that the 3D structures of compounds 1 and 2 are both built up from the linkage of GaO6, GaO5(H2O) and HPO3 2− units by sharing vertices. The structure of compound 2 is constructed from well-known 4.6.12-net connecting layers in the AAAA stacking sequence, which are penetrated by the 1D Ga-O-P chains to form a 3D pillared-layered structure.
γ-Al2O3 with high surface area and large pore volume combined with high thermal stability was synthesized by a reverse precipitation-azeotropic distillation method. The effects of azeotropic distillation on the characteristics of γ-Al2O3 were studied by means of X-ray diffraction(XRD), Fourier transform infrared(FTIR) spectroscopy, transmission electron microscopy(TEM) and N2 adsorption-desorption. The results show that γ-Al2O3 dried by azeotropic distillation has excellent structure characteristics with a high surface area of 426 m2/g and a large pore volume of 2.56 cm3/g. After calcination at 1100 °C, the surface area of γ-Al2O3 was still 92 m2/g with a large pore volume of 1.00 cm3/g, indicating the potential application in catalyst and petroleum industry.
A typical Li+ substituted NiO compound, Li0.29Ni0.71O, was synthesized by molten nitrate method. The effects of Li+ substitution on the structure and magnetic properties of NiO were investigated. X-Ray diffraction(XRD), scanning electron microscope(SEM) and high-resolution transmission electron microscope(HRTEM) analyses confirm the cubic structure of Li0.29Ni0.71O, with a primary particle size of 150 nm. Analysis of the Ni X-ray photoelectron spectroscopy(XPS) shows the transformation from Ni2+ to Ni3+ induced by Li+ substitution. Two magnetic transitions were observed at 225 and 55 K which were assigned to the ferrimagnetic ordering and spin glass transition, respectively. The different magnetic behavior with respect to that of NiO was attributed to the break of superexchange interaction Ni2+-O-Ni2+ and the formation of different spin clusters after non-magnetic Li+ doping.
A simple carbazole hydrozone derivative(1) was synthesized and used as an optical probe for fluoride recognition in CH3CN. Receptor 1 exhibited colorimetric and fluorescent dual-channel response to fluoride anions. Addition of fluoride to a receptor 1 solution in CH3CN induced a distinct color change from yellow to magenta, the solution also displayed significant fluorescence blue shift. Thus receptor 1 exhibited dual-channel responses to fluoride with a high selectivity and sensitivity.
Homogeneous ionic liquid microextraction was developed for the simultaneceus extraction of dimethomorph, mefenacet, isoprothiolane and oxadiazon from soil. 1-Butyl-3-methylimidazolium tetrafluoroborate was used as extraction solvent, and ammonium hexafluorophosphate was used as ion-pairing agent. High-performance liquid chromatography(HPLC) was employed for separation and determination of the analytes. The calibration curves show good linear relationship(r>0.9988). The recoveries are between 74.2% and 97.9% with relative standard deviations(RSDs) lower than 5.97%. The present method is free of volatile organic solvents, and expenditures of sample, extraction time and solvent are lower, compared with ultrasonic and Soxhlet extraction. There was no obvious difference in the extraction recoveries of pesticides obtained by the three extraction methods.
A screening of commercially available lipases for the synthesis of vitamin E succinate showed that lipase from Candida rugosa presented the highest yield. The synthesis of vitamin E succinate in organic solvents with different lgP values ranging from −1.3 to 3.5 was investigated. Of particular interest was that dimethyl sulfoxide (DMSO) with the lowest lgP exhibited the highest yield among all the organic solvents used. It suggests that lgP is incapable of satisfactorily predicting the biocompatibility of organic solvents due to the complexity of enzymatic reaction with hydrophilic and hydrophobic substrates in organic solvent. Effects of different operating conditions, such as molar ratio of substrate, enzyme concentration, reaction temperature, mass transfer, and reaction time were also studied. Under the optimum conditions of 10 g/L enzyme, a stirring rate of 100 r/min, a substrate molar ratio of 5:1 at 55 °C for 18 h, a satisfactory yield(46.95%) was obtained. The developed method has a potential to be used for efficient enzymatic production of vitamin E succinate.
Ten novel N-acyl-3-(3-pyridyl)-5-aryl-pyrazoles were synthesized by Claisen condensation of the aryl methyl ketones with ethyl nicotinate, the cyclization with hydrazine hydrate and the N-acylation with acyl chloride in turn. The structures of all the compounds synthesized were confirmed by means of Fourier transform infrared(FTIR), 1H NMR, mass spectroscopy and elemental analysis. The biological activities of the title compounds were examined by disc diffusion method against Escherichia coli, Staphylococcus aureus, Pyricularia oryzae and Rhizoctnia solani. All the N-acyl-3-(3-pyridyl)-5-aryl-pyrazoles exhibited a certain degree of antibacterial and antifungal activities. Comparatively, compounds 3c and 3d exhibited much significant antibacterial and antifungal activities than the other pyrazole derivatives.
A series of Olaparib derivatives was synthesized, and their structures were confirmed by 1H NMR, MS and elemental analysis. Their antitumor activities on breast cancer susceptbility gene 1/2(BRCA1/2)-deficient cancer cell lines including HCC1937, Capan-1 and MDA-MB-436 were evaluated. The antitumor activity of compound Olaparib-1 was better than the positive control Olaparib in BRCA1-deficient cell line HCC1937.
A novel high-yield Schiff base was designed and synthesized as an anion receptor that specifically select HSO3 − anions in aqueous solutions of H2O/DMSO(15:85, volume ratio), which can be detected via colorimetry under direct visualization. The sensor exhibited different results for other anions, such as F−, Cl−, Br−, I−, H2PO4 −, AcO−, HSO4 − and ClO4 −. The changes in the UV-Vis spectra also show the specific recognition of HSO3 −, rather than similar anions H2PO4 − and HSO4 − in the same aqueous solution. The detection limit of HSO3 − was 1×10−6 mol/L.
A simple and efficient protocol was developed for the syntheses of optically active epoxides(2a–2d) via the reactions of epichlorohydrin with organometallic reagents with steric hindrance at low temperature. On this basis, episulfides(3a–3d) were obtained with high e.e. values by the reaction of the corresponding epoxides with NH4SCN. The configuration of thiiranes was opposite to that of the corresponding epoxides. Then, epoxides 2a–2d were anionically polymerized and the poly-R-2a(or poly-S-2a) was proved to keep a stable one-handed helical conformation in solution. The oligomers[degree of polymerization(DP)=2–5] were obtained when the thiiranes(3a, 3b and 3c) were used to polymerize.
The prodrug, naproxen-eugenol ester, was synthesized by acyl chloride method with naproxen and eugenol as the raw materials. The structure was identified by proton nuclear magnetic resonance(1H NMR), mass spectrometry(MS), infrared spectrometry(IR) and X-ray diffraction. The compound was crystallized in the orthorhombic system, space group P212121 with unit cell dimensions a=0.60563(12) nm, b=1.0234(2) nm, c=3.2654(7) nm, α=90°, β=90°, γ=90°, V=2.0240(7) nm3, Z=4. Calculated density 1.235 Mg/m3; absorption coefficient: 0.083 mm−1; F(000)=800; final R 1=0.0564. The analgesic activity and anti-inflammatory were similar to those of naproxen, and the results of ulcerogenic activity indicate that the prodrug can significantly decrease the irritation after oral administration.
Carbohydrates, with broad-spectrum structures and biological functions, are key organic compounds in nature, along with nucleic acids and proteins. As part of our ongoing efforts to develop a new class of pesticides with novel mechanism of action, a series of novel N-glycosyl-1-pyridyl-1H-pyrazole-5-carboxamide was designed and synthesized via the reactions of glycosyl methanamides and pyridyl-pyrazole acid. The compounds were characterized by 1H NMR and 13C NMR. The bioassay results indicate that some of these compounds exhibit moderate insecticidal activities and assessed as potential inhibitors of calcium channels. The modulation of voltage-gated calcium channels by compounds 4a and 5a in the central neurons isolated from the third instar larvae of Spodoptera exigua was studied by whole-cell patch-clamp technique. In addition, compound 5a inhibits the recorded calcium currents reversible on washout. Experimental results also indicate that compound 5a did not release stored calcium from the Endoplasmic Reticulum. The present work demonstrates that N-glycosyl-1-pyridyl-1H-pyrazole-5-carboxamides cannot be used as possible inhibitors of calcium channels for developing novel pesticides.
A proline functionalized fiber catalyst was employed for aldol reactions in water. In the presence of the fiber catalyst, the aldol reactions proceeded smoothly at 40 °C and the products were obtained in excellent yields which were higher than those obtained for the reactions catalyzed by L-proline or trans-4-hydroxy-L-proline. This newly developed fiber catalyst is applicable to the reactions of a wide range of aromatic aldehydes and exhibits excellent reusability(up to 6 times) without any additional treatment.
As the strongest electronegative element, fluorine can stimulate the production of superoxide radicals in cells. In view of the important roles of kidneys in bone metabolism, the authors analyzed the quantitative pathomorphological characteristics of renal damage and the potential cellular apoptosis and oxidative stress mechanisms in rats treated with excessive fluoride. Wistar rats were exposed to 50 mg F−(110.5 mg NaF)/L, 100 mg F−(221.0 mg NaF)/L and 150 mg F−(331.5 mg NaF)/L in drinking water for 70 and 140 d, respectively. Microscope with image analysis was used to quantitate pathomorphological changes in renal tissues of the rats. Reactive oxygen species(ROS), the cell cycle and apoptosis of renal cells were measured by flow cytometry and TUNEL technique(terminal deoxynucleotidyl transferase dUTP nick end labeling), respectively. The ion concentrations in serum and renal functional parameters were detected by automatic biochemical analyzer. Quantitative analysis results demonstrate the expanded Bowman’s space of glomerulus and obvious dilatation of renal tubule. TUNEL technique revealed that NBT/BCIP (nitro blue tetrazolium/5-bromo-4-chloro-3′-indolylphosphate, p-toluidine salt)-staining positive apoptotic cells selectively located in medullocortical junction areas. The data suggest that renal damage in chronic fluorostic rats is associated with the cellular apoptosis and oxidative stress.
Gene therapy is a potentially powerful tool used in cancer therapy. The strength of immune responses induced by some strategies is usually low, therefore, the development of agents capable of enhancing these responses is highlighted. The authors investigated the potential of an approach based on the hemagglutinin-neuraminidase(HN) of Newcastle disease virus(NDV) as a potential immune adjuvant. It was found that recombinant adenovirus(Ad) infected SGC7901 cells expressing HN exhibited both hemagglutinin(HA) and neuraminidase(NA) activities. It was demonstrated that administration of HN induced higher levels of the effector cytokines TNF-α, IFN-α and IFN-γ and increased natural killer(NK) cell activity. Based on the therapeutic tumor model, the results show that the administration of HN with Apoptin led to improved survival and tumor suppression. In conclusion, this study indicates that HN stimulates innate immune responses to make the activity of NK cells increased, which highlights the potential adjuvant activity of HN in cancer gene therapy.
Mistletoe alkali plays an important role in salivary adenoid cystic carcinoma(SACC) cell proliferation, apoptosis and invasion. Mistletoe alkali shows potent anticaner property. In this paper, immunocytochemical and immunofluorescence staining were employed to evaluate the expression levels of proliferating cell nuclear antigen( PCNA), Caspase 3, Caspase 8 and Caspase 9. Apoptosis was detected by acridine orange/ethidium bromide (AO/EB) staining, cell invasion ability was assessed by Boyden Chamber assay. Pretreatment with mistletoe alkali markedly decreased PCNA expression in SACC cells in a dose-dependent manner(P<0.001) and also led to increase the expression of Caspase 3, Caspase 8 and Caspase 9 in SACC cells compared with control group(P<0.001). Number of apoptotic cells increased dramatically in mistletoe alkali group(P<0.001). In Boyden Chamber assay, mistletoe alkali treatment could inhibit SACC cells to penetrate the artificial basement membrane compared with control group(P<0.01). Mistletoe alkali remarkably inhibited the proliferation and invasion of SACC cells and induced the apoptosis of SACC cells. These results provide an insight into the mechanisms of anticancer effects of mistletoe alkali, and highlight the potential clinical application of it.
SAV1 is a core component involved in the Hippo pathway which can control the organ size via regulating cell proliferation and apoptosis simultaneously. We explored the regulatory mechanism of SAV1. We established the HEK293T cell pool, the cells in which can stably express SAV1 by retroviruses infection and found that SAV1 stable cells reduced the movement of themselves and resulted in multicellular aggregation. We purified SAV1 interacting protein complex using streptavidin resin and subsequently analyzed the digested peptides by high performance liquid chromatography(HPLC)-MS/MS. Results show that about 150 proteins were identified in the complex of SAV1 with protein. TUBA1A, OTUD4, and ATD were identified as proteins interacting with SAV1. Importantly, PP1A, serine/threonine protein phosphatase PP1-alpha 1 catalytic subunit, was also in the top 10 list. The interaction between PP1A and SAV1 was detected by both co-immunoprecipitation(CO-IP) and immunostaining. Our results indicate that PP1A might be the phosphatase of SAV1 and may take part in the regulation of the Hippo pathway.
Calcium-phosphate compounds(Ca-P) coating was prepared on an Mg-Al alloy(AZ60). Biodegradation of Ca-P coated magnesium alloy was evaluated in simulated body fluid(SBF) by examining the changes in magnesium ion concentration and pH value, which indicated that the Ca-P coating on magnesium alloy strongly affected the corrosion of magnesium alloy. Osteoblast MC3T3-E1 cells were utilized to investigate the cellular cytocompatibility. The cytocompatibility was measured by carrying out a series of tests, such as cholecystokinin-octapeptide(CCK-8) test, alkaline phosphatase activity(ALP) test, cellular morphology of hematoxylin-eosin(HE) staining and the induction of apoptosis. It was found that the cell function showed better in the Ca-P coated Mg-alloy extract than in the uncoated magnesium alloy extract. In summary, the results indicate that the Ca-P coating can improve the corrosion resistance of magnesium alloy and elevate cellular proliferation and differentiation of osteoblast MC3T3-E1 cells.
Porcine reproductive and respiratory syndrome(PRRS) caused by porcine reproductive and respiratory syndrome virus(PRRSV) is one of the most infectious diseases in the swine industry worldwide, causing big economic losses. Vaccines are major weapons against PRRSV, however, current available vaccines have several limitations. Developing chemical drugs as alternatives is required. On the basis of traditional medical knowledge, we purposely selected 15 natural products originated from Chinese herbs with anti-infectious effects. Their antiviral activities were evaluated by PRRSV-induced cytopathic effect(CPE) on MARC-145 cells and reverse transcription polymerase chain reaction(RT-PCR) assay. Compounds ethoxysanguinarine(EOSG) and atractylodinol were found to be the hits which could significantly reduce PRRSV-associated CPE with 50% inhibited concentration(IC50) values of 7.9 and 39.4 μmol/L, respectively. Meanwhile, compounds ethoxysanguinarine and atractylodinol significantly decreased mRNA expression of ORF7 gene in a dose-dependent manner. Study results suggest that compounds ethoxysanguinarine and atractylodinol may be useful anti-PRRSV drugs for swine industry or the hits for further lead optimization.
Bioleaching of oil shale by Bacillus mucilaginosus was carried out in a reaction column for 13 d. The pH value of the leaching liquor decreased steadily from 7.5 to 5.5 and the free silicon dioxide concentration reached approximately 200 mg/L in it. Scanning electron microscopy(SEM) observations revealed that a mass of small particles separated from the matrix of oil shale. Energy dispersive spectrometry(EDS) analysis implied that the total content of Si,O, Al was decreased in the particle area of the matrix. These facts indicate that the silicate was removed, leading to the structural transformation of oil shale. Comparison of the shale oil yields before and after bioleaching illustrated that approximately 10% extra shale oil was obtained. This finding suggests that the demineralisation of the oil shale by silicate bacteria improves shale oil yield.
Alternative mechanisms of toxic effects induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD), instead of the binding to aryl hydrocarbon receptor(AhR), have been taken into consideration. It has been recently shown that TCDD reduces rapidly the activity of CK2(casein kinase II) both in vivo and in vitro. It is found that TCDD has high molecular similarities to the known inhibitors of CK2 catalytic subunit(CK2α). This suggests that TCDD could also be an ATP-competitive inhibitor of CK2α. In this work, docking TCDD to CK2 was carried out based on the two structures of CK2α from maize and human, respectively. The binding free energies of the predicted CK2α-TCDD complexes estimated by the molecular mechanics/Poisson-Boltzmann surface area(MM/PBSA) method are from −85.1 kJ/mol to −114.3 kJ/mol for maize and are from −96.1 kJ/mol to −118.2 kJ/mol for human, which are comparable to those estimated for the known inhibitor and also ATP with CK2α. The energetic analysis also reveals that the van der Waals interaction is the dominant contribution to the binding free energy. These results are also useful for designing new drugs for a target of overexpressing CK2 in cancers.
Li2MnO3-doped spinel LiMn2O4 composites were synthesized by sol-gel method to improve the electrochemical performance of LiMn2O4. The microstructures, morphologies and electrochemical performance of the obtained xLi2MnO3·(1-x)LiMn2O4 composites were characterized by X-ray diffraction(XRD), scan electron microscopy(SEM) and a galvanostatic charge-discharge process. It was found that both Li2MnO3 and LiMn2O4 components exist in xLi2MnO3·(1-x)LiMn2O4(0<x<1) composites. The 0.3Li2MnO3·0.7LiMn2O4 composite shows the optimized electrochemical performance, including discharge capacity and cycle stability. It was demonstrated that Li2MnO3-doped spinel LiMn2O4 cathode material can work at wide potential window with quite good capacity retention and considerably larger reversible capacity compared to single-phase LiMn2O4 component.
The phase equilibria of quaternary system NaCl-NaBr-Na2B4O7-H2O at 348 K were studied by the isothermal equilibrium method. The solubilities and densities of the equilibrium solution were determined. According to the experimental data, the phase diagram, density-composition diagrams and water content diagram of the quaternary system at 348 K were plotted respectively. And the phase diagram consists of one univariant curve, two crystallization fields and without any invariant point of the quaternary system. The equilibrium solid phases of the two crystallization fields were Na(Cl, Br) and Na2B4O7·5H2O. The experimental results show that the quaternary system contained solid solution. The densities of the solution decrease with increasing NaCl concentration and increase with increasing NaBr concentration.
An activated foam-structured carbon-ceramic(AFCC) was prepared and investigated as TiO2 support for the photocatalytic degradation of phenol. AFCC and TiO2/AFCC catalysts were characterized by N2 adsorption-desorption and X-ray diffraction(XRD). The effects of AFCC on the photocatalytic activity and the crystallinity of TiO2 were studied. The results show that the crystallinity and anatase/rutile ratio of TiO2 loaded on AFCC could be significantly influenced by the calcination temperature. The degradation rate of phenol benefited from the synergistic effects of the adsorption of activated carbon(AC) and the photocatalysis of TiO2, which suggests that a high surface area of AC is essential to achieve high degradation rates and efficiencies. It was found that the larger mean cell size of AFCC increased the light transmission within the foam.
The influence of the wettability of a catalyst on the performance of the liquid phase oxidation of p-cresol was investigated. It was found that the surface hydrophobicity of a catalyst, which can be changed by modification with various loadings of polyvinylidene fluoride(PVDF), has a promotion effect on the catalytic performance. At the same time, the reaction parameters such as oxygen pressure, molar ratio of NaOH to p-cresol, reaction temperature and time on the catalytic performance in the liquid-phase oxidation of p-cresol were optimized. As a result, 10%(mass fraction) PVDF modified cobalt pyrophosphate gave the highest conversion of 94.2% of p-cresol with a selectivity of 94.4% for p-hydroxybenzaldehyde at 348 K and a molar ratio of 4:1 of NaOH/p-cresol and an oxygen pressure of 1.0 MPa for 3 h.
The electrochemical behavior of Al(III) ions was studied in molten LiCl-KCl melts on a molybdenum electrode. Cyclic voltammetry, chronopotentiometry and chronoamperometry were used to explore the deposition mechanism of Al and Li. Cyclic voltammetry expriment indicates that under potential deposition(UPD) of lithium on pre-deposited aluminium led to the formation of liquid Al-Li alloys at 853 K. The diffusion coefficient of Al(III) ions at 853 K in LiCl-KCl-AlF3(1%, mass fraction) melts was determined to be (2.79±0.05)×10−5 cm2/s. Chronopotentiograms and chronoamperograms demonstrate that the codeposition of Al(III) and Li(I) ions formed Al-Li alloys at cathodic current densities higher than −0.28 A/cm2 or cathodic potentials more negative than −2.20 V. X-Ray diffraction( XRD) pattern indicates that Al-Li alloys with different phases formed via galvanostatic electrolysis. Inductively coupled plasma(ICP) analyses of the samples obtained by electrolysis show that lithium and aluminium contents of Al-Li alloys could be controlled by AlF3 concentration and current intensity.
LiNi0.5Mn1.5O4 prepared by a spray drying method was re-treated in N2 at 500, 600 and 700 °C, respectively. Their structural and electrochemical properties were studied by means of Fourier transform infrared(FTIR), X-ray diffraction(XRD), and charge-discharge tests. The space group of the LiNi0.5Mn1.5O4 transforms from P4332 to $Fd\bar 3m$ at an annealing temperature of 700 °C. The electrochemical characteristics of the treated samples are closely related to the annealing temperature. The sample treated in N2 at 500 °C shows both an improved rate capability and cyclic performance at a high temperature compared with the as-prepared sample, while the sample treated in N2 at 700 °C shows dramatically decrease in its reversible capacity.
ZnO thin films were prepared by a chemical etching method and their wettability was investigated. The structure and surface composition structure were characterized by means of scanning electron microscopy, X-ray photoelectronic spectrometry(XPS), X-ray diffraction(XRD) and Raman spectrometry. These analyses reveal that the etched films were large-scale micro-nanohierarchical structures composed of a Zn core and a ZnO coating. Superhydrophobic surfaces with water contact angles of over 150° were obtained by n-octadecanethiol(ODT) modification. The XPS and Raman results indicate that ODT molecules were bound to the ZnO surface with the S head group by forming Zn—S bond.
Since large amounts of oils, surfactants and penetration enhancers used in microemulsion systems might lead to seriously skin irritation, the percutaneous absorption and penetration of indomethacin(IMC, model drug) from O/W microemulsion were enhanced by simply changing the composition of cosurfactants. Pseudo-ternary phase diagrams were constructed with mixed cosurfactants at different ratios. Hairless rat skin was used as a barrier for permeation experiments. Four formulations were prepared with fixed oil, surfactant and different cosurfactant content(4%, 20% and 20%, mass fraction), and formulation F4 with menthol added was evaluated to compare the enhancement effect of it with those of mixed cosurfactants. The O/W microemulsion region was the largest when the mass ratio of ethanol/transcutol was 1:1. However, the region changed slightly for the system with incorporated mixed cosurfactants propylene glycol/transcutol. The flux and skin retention of IMC from O/W microemulsion with mixed cosurfactants were much higher than that with single cosurfactant(P<0.01), while incorporation of menthol would only enhance the drug flux through the skin. To conclude, mixed cosufactants could affect the phase behavior and improve the percutaneous absorption and penetration of IMC. Based on this, it provided a promising solution to enhance drug release from microemulsions without raising potential skin damage.
A fluctuating charge interaction potential function for alanine-water was constructed in the spirit of newly developed ABEEMσπ/MM(atom-bond electronegativity equalization method at the σπ level fused into molecular mechanics). The properties of gaseous neutral alanine-(H2O) n(n=1–7) clusters were systematically investigated by quantum mechanics(QM) and the constructed ABEEMσπ/MM potential, such as conformations, hydrogen bonds (H-bonds), interaction energies, charge distributions, and so on. The results of ABEEMσπ/MM model are in fair agreement with those of QM and available experimental data. For isolated alanine, compared with those of experimental structure, the average absolute deviations(AAD) of bond length and bond angle are 0.002 nm and 1.4°, respectively. For alanine-water clusters, the AAD of interaction energies and H-bond lengths are only 3.77 kJ/mol and 0.012 nm, respectively, compared to the results of MP2/aug-cc-pVDZ//MP2/6-311+G** method. The ABEEMσπ charges fluctuate with the changing conformation of the system, and can accurately and reasonably reflect the interpolarization between water and alanine. The presented alanine-water potential function may provide a basis for further simulations on related aqueous solutions of biomolecules.
The structures, energetics, and isomerization of a possible interstellar [Si, O, S] system were explored at the CCSD(T)/aug-cc-pVQZ//CCSD(T)/aug-cc-pVTZ level. On the schemaitc potential energy surface(PES), we found that silicon oxysulfide(OSiS) produced in laboratory is the global minimum. An analysis of the Wiberg bond index(WBI), bond order and the bond length, shows that silicon oxysulfide contains SiO and SiS double bonds in accordance with the results of Schnöckel. Besides silicon oxysulfide, another interesting cyclic minimum(c-SiOS) was found to have a very high kinetic stability stabilized by the least barrier of 120.9 kJ/mol. In light of the fact that no cyclic sulfide-containing species has been detected in space, c-SiOS could be a very promising candidate. The presented results might provide useful information on detected interstellar molecules O=Si=S and c-SiOS.
An interesitng class of organic A-π-D-π-A dyes based on an N,N,N′,N′-tetraphenylbenzidine(TPD) unit as donor was designed and synthesized for dye-sensitized solar cells(DSSCs). TPD-4-based DSSCs gave a short circuit photocurrent density(J sc) of 16.67 mA/cm2, a open circuit voltage(V oc) of 0.635 V and a fill factor(ff) of 0.68, achieving a solar-to-electricity conversion efficiency(η) of 7.22% in preliminary tests. The N3-sensitized device gave an η value of 8.02% with a J sc of 18.81 mA/cm2, a V oc of 0.630 V and an ff of 0.68 under the same conditions. The incident photo-to-current efficiency(IPCE) values above 70% observed in a range of 460 to 600 nm with a maximum value of 80% at 500 nm indicate that the TPD-4-based DSSC shows a high performance. Under the same conditions, the DSSC based on N3 provided the IPCE values above 70% in a range of 490 to 580 nm with a maximum value of 76% at 500 nm. Both further optimization of the device processing and structural modification of these dyes are anticipated to make the device give even better performances.
The molecular structures of the ground and the lowest triplet states for a series of Pt(II) complexes PtLCl(1)[L=6-(2-hydroxyphenyl)-2,2′-bipyridine], Pt(pp)2[pp=2-(2-hydroxyphenyl)pyridine](2), PtbpyCl2(bpy=2,2′-bipyridine)(3), and the free tridentate L ligand(4) were optimized by the density functional theory B3LYP and UB3LYP methods, respectively. On the basis of optimized geometries, the spectral properties were investigated with time-dependent density functional theory(TD-DFT). In comparison with those of complexes 2 and 3, the more rigid structure of complex 1 together with its low rate of the radiationless decay via nonemissive d-d state leads to higher photoluminescence quantum efficiency. And the phosphorescence quantum efficiency of complex 1 can be easily controlled by modifying auxiliary ligands. The introduction of fluorine ligand into complexes can effectively increase the radiation transition rate and decrease the radiationless d-d transition rate, and as a result, a novel complex PtLF(5) might be a good phosphorescent material suitable for organic electronic devices.
Molecular dynamics simulation was used to study the ionic liquid(IL) crystalline film based on 1-ethyl-3-methylimidazolium bis[trifluoromethylsulfonyl]imide([emim][Tf2N]) and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate([emim][TfO]) on the graphite surface. Our results show that the cations are parallelly distributed to the surface in the 1/2 monolayer(ML) crystalline film. The [Tf2N]− anions are parallel to the surface with the oxygen atoms at the bottom, whereas the [TfO]− anions are perpendicularly distributed to the surface also with the oxygen atoms at the bottom in the 1/2 ML crystalline film. It has been found that the IL-vapor interface strongly influences the arrangement of ions at the interface. The anions in the top layer with the oxygen atoms outmost turn over to make themselves with the F atoms outmost so as to form C—H…O hydrogen bonds with the cations. The calculated orientational ordering shows that in the outmost layer at the IL-vapor interface, the cation rings present either parallel or perpendicular to the surface at 350 K.
Sodium sulfate as an electrolyte additive was studied via electrochemical methods including linear sweep voltammetry(LSV), cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) to deeply understand its effect on the hydrogen evolution current and overpotential as well as the formation and structure of anodic passivation films on lead surface during the redox processes. The results achieved will be valuable to improve the cycle life and maintenance-free properties of lead-acid batteries.
A simple, surfactant-free, and environmentally benign method has been developed to synthesize a novel 3D flocculus-like CuO hierarchical nanostructure self-assembled with 2D nanosheet as building blocks. Detailed proofs demonstrate that the overall synthetic process underwent the dehydration and re-crystallization of precursor Cu(OH)2 nanowires, and the subsequent two-step oriented attachment. In addition, 3D butterfly-like and flower-like CuO nanostructures consisted of 2D nanosheets could be obtained by adjusting the concentration of NaOH(c NaOH) in the solution. c NaOH played a key role in tailoring the thickness of the nanosheets and changing the morphology of the product. This report may be helpful to constructing fine-tune hierarchical CuO nanostructures under basic conditions.
A series of azobenzene functionalized poly(aryl ether) copolymers(azo-PAEs) containing azo moieties on pendants was prepared by direct copolymerization. The amount of azobenzene chromophores could be controlled by the feed ratio of azo-monomer. Their chemical structures and properties were characterized by means of infrared(IR) spectrometry, UV-Vis, hydrogen nuclear magnetic resonance(1H NMR), difference scanning calorimetry(DSC), and thermogravimetric analysis(TGA). The results suggest that azo-PAEs had high glass transition temperatures(T gs) and good thermal stability. By exposing their spin-coated films to an interference pattern laser beam, azo-PAEs could be used for the fabrication of thermal stable surface relief gratings(SRGs).
A new pH-responsive block copolymer, methoxy poly(ethylene glycol)-b-poly[5-methacrylamido-pentylamine hydrochloride](mPEG-b-PMAAPA) was synthesized and characterized in this paper. The monomer 5-methacrylamido-pentylamine hydrochloride(MAAPA) and the macroinitiator(mPEG-ACVA) were synthesized, respectively, and mPEG-b-PMAAPA was then obtained by free radical polymerization. The structure and molecular weight of mPEG-b-PMAAPA were confirmed by hydrogen nuclear magnetic resonance(1H NMR) spectroscopy and gel permeation chromatography with multiangle laser light scattering(GPC-MALLS) measurements. At a low pH, it is hydrophilic due to the protonation of the primary amine groups. With increasing pH value, deprotonation occurs and the hydrophobicity of PMAAPA block increases. This molecular feature leads to interesting aggregation behavior of mPEG-b-PMAAPA in aqueous solutions at different pH values as revealed by dynamic light scattering(DLS) measurements, transmission electron microscopy(TEM) observations and resonance light scattering(RLS) measurements.
Partly imidized polyamic acid(PAA) has been used to prepare high performance polyimide films. The behaviors of two polyamic acids derived from pyromellitic dianhydride(PMDA)/4,4′-oxydianiline(ODA) and 3,3′,4,4′-biphenyltetracarboxylic diahhydride(BPDA)/paraphenylenediamine(PPD) containing dehydrating agents composed of acetic anhydride and a tertiary amine as the catalyst were investigated. The gel point was dependent on imidization degree in despite of temperature and the molar ratio of catalyst to acetic acid. Imdization content was about 35% for PMDA/ODA and about 22% for BPDA/PPD. The effect of catalyst on imidization possessed an order of triethylamine>3-methylpyridine>pyridine>isoquinoline>2-methylpyridine. The stretching of the films greatly reduced the coefficient of linear thermal expansion(CTE) either in the longitudinal direction or transversal direction. Compared to the film from polyamic acid, the partly imidized film had greater stretching ratio, so that the uniaxial stretched polyimide film from partly imidized PAA had higher tensile strength and tensile modulus, but lower elongation in the stretching direction.