Sorption of radioeuropium onto attapulgite: effect of experimental conditions

Batch sorption experiments were performed to remove Eu(III) ions from aqueous solutions by using attapulgite under ambient conditions. Different experimental conditions, such as contact time, solid content, foreign ions, pH, ionic strength, fulvic acid and temperature, have been investigated to study their effect on the sorption property. The results indicated that the sorption of Eu(III) onto attapulgite was strongly dependent on pH, ionic strength and temperature. The sorption increased from about 8.9 to 90% at pH ranging from 2 to 6 in 0.01 mol/L NaNO₃ solution. The Eu(III) kinetic sorption on attapulgite was fitted by the pseudo-second-order model better than by the pseudo-first-order model. The sorption of Eu(III) onto attapulgite increased with increasing temperature and decreasing ionic strength. The Langmuir and Freundlich models were used to simulate the sorption isotherms, and the results indicated that the Freundlich model simulated the data better than the Langmuir model. The thermodynamic parameters (∆G ^o, ∆S ^o, ∆H ^o) were determined from the temperature dependent isotherms at 298.15, 318.15 and 338.15 K, and the results indicated that the sorption reaction was an endothermic and spontaneous process. The results suggest that the attapulgite is a suitable material as an adsorbent for preconcentration and immobilization of Eu(III) from aqueous solutions.     

Synthesis,Crystal Structure,and Properties of the 3D Porous Framework [Zn(INAIP)]·DMA·H2O

A new three‐dimensional (3D) porous framework [Zn(INAIP)] · DMA · H₂O ( 1 ) [INAIP = 5‐(isonicotinamido)isophthalate, DMA = N,N′‐dimethylacetamide] was synthesized by solvothermal methods and characterized by single‐crystal and powder X‐ray diffraction, as well as thermogravimetric analysis. The results of X‐ray diffraction analyses revealed that complex 1 has an unusual 3D architecture with the (3,6)‐connected rutile ( rtl ) topology. The adsorption behavior shows that compound 1 exhibits selective adsorptions of CO₂ over N₂ after the removal of the solvent molecules within the pores.     

A dual microsphere based on PLGA and chitosan for delivering the oligopeptide derived from BMP-2

In this paper, we document the process and findings of preparing dual poly (lactide-co-glycolide)/chitosan microspheres (PLGA/CS MSs) for osteoinductive oligopeptide derived from BMP-2 (abbreviated as Peptide-24). Through adjusting the amount of Peptide-24, three kinds of PLGA/CS MSs were successfully constructed in twice encapsulations. We studied the morphology, size distribution and loading efficiency of the PLGA/CS MSs. We also focused on the pH change of the environment and the molecular weight of the matrix during the degradation process of PLGA/CS MSs. More specifically, the release of Peptide-24 from three kinds of PLGA/CS MSs was monitored in PBS at 37 °C and pH 7.4. The structural stability of the released Peptide-24 was detected by Far-UV circular dichroism and MALDI-TOF-MS analysis. The mean sizes of the three kinds of PLGA/CS MSs are 47.5, 63.0 and 89.1 μm; and their drug-loading rates are 2.61, 3.21 and 2.21%, respectively. Comparing with Chitosan microspheres (abbreviated as CS MSs), the PLGA/CS MSs have excellent release curves with zero-order kinetics and controllable model. The incubation solution of PLGA/CS MSs avoided producing acid environment as poly (lactide-co-glycolide) microspheres (PLGA MSs) did, which was explained by analyzing the molecular weight of the matrix. The released oligopeptide kept its original structure and relative molecular weight throughout the procedures of encapsulation, storage and release. This indicates its structure stability. Thus, we conclude that dual PLGA/CS MSs is a promising vehicle that is suitable for the delivery of bioactive factors.     

Comparison and optimisation of biodiesel production from <Emphasis Type="Italic">Jatropha curcas</Emphasis> oil using supercritical methyl acetate and methanol

In this study, biodiesel has been successfully produced by transesterification using non-catalytic supercritical methanol and methyl acetate. The variables studied, such as reaction time, reaction temperature and molar ratio of methanol or methyl acetate to oil, were optimised to obtain the optimum yield of fatty acid methyl ester (FAME). Subsequently, the results for both reactions were analysed and compared via Response Surface Methodology (RSM) analysis. The mathematical models for both reactions were found to be adequate to predict the optimum yield of biodiesel. The results from the optimisation studies showed that a yield of 89.4 % was achieved for the reaction with supercritical methanol within the reaction time of 27 min, reaction temperature of 358°C, and methanol-to-oil molar ratio of 44. For the reaction in the presence of supercritical methyl acetate, the optimum conditions were found to be: reaction time of 32 min, reaction temperature of 400°C, and methyl acetate-to-oil molar ratio of 50 to achieve 71.9 % biodiesel yield. The differences in the behaviour of methanol and methyl acetate in the transesterification reaction are largely due to the difference in reactivity and mutual solubility of Jatropha curcas oil and methanol/methyl acetate.     

Mechanical properties of hybrid inorganic-organic framework materials: establishing fundamental structure-property relationships

The mechanical properties of hybrid framework materials, including both nanoporous metal-organic frameworks (MOFs) and dense inorganic-organic frameworks, are discussed in this critical review. Although there are relatively few studies of this kind in the literature, major recent advances in this area are beginning to shed light on the fundamental structure-mechanical property relationships. Indeed research into the mechanical behavior of this important new class of solid-state materials is central to the design and optimal performance of a multitude of technological applications envisaged. In this review, we examine the elasticity of hybrid frameworks by considering their Young's modulus, Poisson's ratio, bulk modulus and shear modulus. This is followed by discussions of their hardness, plasticity, yield strength and fracture behavior. Our focus is on both experimental and computational approaches. Experimental work on single crystals and amorphized monoliths involved primarily the application of nanoindentation and atomic force microscopy to determine the elastic moduli and hardness properties. The compressibility and bulk moduli of single crystals and polycrystalline powders were studied by high-pressure X-ray crystallography in the diamond anvil cell, while in one instance spectroscopic ellipsometry has also been used to estimate the elastic moduli of MOF nanoparticles and deposited films. Theoretical studies, on the other hand, encompassed the application of first principles density-functional calculations and finite-temperature molecular dynamics simulations. Finally, by virtue of the diverse mechanical properties achievable in hybrid framework materials, we propose that a new domain be established in the materials selection map to define this emerging class of materials (137 references).     

Synergistic antibacterial brilliant blue/reduced graphene oxide/quaternary phosphonium salt composite with excellent water solubility and specific targeting capability

A water-soluble brilliant blue/reduced graphene oxide/tetradecyltriphenylphosphonium bromide composite (BB-rGO-TTP) was prepared by using noncovalent brilliant blue-functionalized reduced graphene oxide (BB-rGO) as the tetradecyltriphenylphosphonium bromide (TTP) carrier. Antibacterial performance of this novel composite was investigated for both Gram-positive and Gram-negative bacteria. The results showed that the novel BB-rGO-TTP, combing the advantages of graphene and TTP, displayed excellent synergistic antibacterial activity, specific targeting capability, water solubility, and mild cytotoxicity, suggesting the great potential application as sprayable graphene-based antibacterial solutions.     

Hydrothermal synthesis of cubic boron nitride microcrystals

In this paper, combining the hydrothermal method and halide species-inducing effect, we reported cubic-phase BN microcrystals synthesized in hydrothermal condition with N(CH₃)₃ as nitrogen source. These polyhedral microcrystals presented nearly regular octahedral shapes of 0.5?C1.5 ??m in average size.     

Efficient assembly of multi-walled carbon nanotube-CdSe/ZnS quantum dot hybrids with high biocompatibility and fluorescence property

CdSe/ZnS core-shell quantum dots (QDs) were efficiently tethered onto polyamidoamine dendrimer-modified multi-walled carbon nanotubes (MWCNTs) by covalent linkage and mercapto-mediated assembly. The obtained MWCNT-QD hybrids were both photophysically and morphologically characterized. The QDs are well-distributed on single nanotube surface in high density and the assembly of QDs onto MWCNTs does not change the fluorescence emission wavelength of QDs but significantly decreases the emission density. Cytotoxicity of MWCNT-QD hybrids to HeLa cells and their fluorescence property in living cell system were evaluated in detail. The hybrids show a little effect on cell viability even at very high concentration (100 μg mL(-1)). Moreover, they possess intense red fluorescence signal under optical fluorescence microscopy and good fluorescence stability over 72-h exposure in living cell system.     

Sol–gel synthesis and characterization of titania monolith with bimodal porosity

Monolithic titania materials with macro-mesoporosity bimodal texture have been prepared through a template-free sol–gel approach, based on the reaction of hydrolysis and polycondensation of titanium isopropoxide promoted by the slow released water from esterification between acetic acid and methanol under a strong acidic condition. With the coarsening of the titania oligomers, phase separation and sol–gel transition processes take place so as to form a homogeneous gel system that will change into a monolith after aging, drying and heat treatment. The synthesized titania monolith possesses a specific surface area of 77 m² g⁻¹ (calcined at 350 °C), an anatase with partly rutile crystallite structure and great mechanical strength. The synthesis method applied here is simple and easy to implement as no extra chemical modifier such as poly(ethylene oxide) (PEO) and formamide is needed to control the process. The properties of biomodal porous structure, satisfactory surface area and high mechanical strength will enable the monolith to be served as a chromatography column to separate phosphorus organo-compounds.     

脲和盐酸胍诱导的卵清溶菌酶分子去折叠过程中各稳定构象态的分布和过渡

以内源荧光光谱和荧光相图法研究了脲和盐酸胍诱导的卵清溶菌酶分子的去折叠过程,结果表明,当变性液中脲和盐酸胍的浓度分别约为4.0和3.0 mol/L时,卵清溶菌酶分子的去折叠过程均存在一个折叠中间态,这两个去折叠过程均符合"三态模型".在卵清溶菌酶分子"三态"去折叠过程的基础上,通过变性剂分子和卵清溶菌酶分子之间的缔合一...