[en] Methotrexatum intercalated layered double hydroxides (MTX/LDHs) hybrids were synthesized by the co-precipitation method and three kinds of nonionic surfactants with different hydrocarbon chain lengths were used. The resulting hybrids were then characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). XRD and FTIR investigations manifest the successful intercalation of MTX anions into the interlayer of LDHs. TEM graphs indicate that the morphology of the hybrids changes with the variation of the chain length of the surfactants, i.e., the particles synthesized using polyethylene glycol (PEG-7) present regular disc morphology with good monodispersity, while samples with the mediation of alkyl polyglycoside (APG-14) are heavily aggregated and samples with the addition of polyvinylpyrrolidone (PVP-10) exhibit irregular branches. Furthermore, the release and bioassay experiments show that monodisperse MTX/LDHs present good controlled-release and are more efficient in the suppression of the tumor cells. - Highlights: • Surfactants could be used to modify the dispersing state of MTX/LDHs hybrids. • Surfactants have great effect on the morphology of MTX/LDHs hybrids. • MTX/LDHs with good monodisperse degree are more efficient in the suppression of the tumor cells

[en] Graphical abstract: The intercalation of methotrexatum (MTX) into layered double hydroxides (LDHs) via an exfoliation-reassembly process was studied and the resulting MTX/LDHs hybrids were evaluated by anticancer effects on A549 cells together with pristine LDHs and MTX itself, the results indicated that the hybrids obtained from low concentration of MTX solution presented much better anticancer effect. - Highlights: • Exfoliation-reassembly process is a good method to synthesize hybrids. • MTX/LDHs from low concentration of MTX solution presented better release property. • MTX/LDHs from low concentration of MTX solution presented good anticancer effects. - Abstract: In this paper, the intercalation of methotrexatum (MTX) into layered double hydroxides (LDHs) via an exfoliation-reassembly process was reported and the resulting hybrids were then characterized by X-ray diffraction (XRD) patterns, Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM) patterns etc. In the synthesis procedure, LDHs particles were firstly delaminated into well-dispersed 2D nanosheets in formamide by ultrasonic treatment at room temperature, and then the resulting LDH nanosheets were reassembled in MTX solution to form MTX intercalated LDH (MTX/LDHs) hybrids. AFM images showed that during the exfoliation process a large part of LDHs particles were delaminated into single and double brucite layers. XRD patterns and FTIR investigations manifested the successful intercalation of MTX anions into LDHs interlayers for the final samples. It was also found out that the drug-loading capacity of the hybrids increased with the concentrations of MTX solutions, while the morphology became even aggregated. At last, the cell cytotoxicity of the hybrids was estimated by MTT assays on the human lung cancer cells (A549), and the results stated that MTX/LDHs hybrids had effective suppress role on the proliferation of cancer cells

[en] Refined vegetable oils are the main feedstocks for biodiesel production presently. However, the source and price of refined vegetable oils always restrict the development of biodiesel industry in many regions. Large amount of cheap soapstocks (SSs) are currently available in oil refining process, which may provide potential feedstocks reservoir. In this paper, one technical route involving acidification, separation of free fatty acids (FFAs) and glycerides through molecular distillation, followed by esterification and transesterification, respectively, was proposed for effective conversion of SSs. The acid oil obtained from acidification of SSs was distilled at 180 C to isolate FFAs and glycerides. Esterification was then catalyzed by solid superacid catalyst, SO₄^2-/ZrO₂-TiO₂/La³⁺, with a methanol to oil ratio of 15:1, catalyst amount of 5 wt.% and reaction time 4 h at 60 C. The conversion efficiency could reach 98.02%. Transesterification with glycerides was also carried out with methanol to oil molar ratio of 5:1 and catalyst (sodium methoxide) amount of 0.6% and reaction time 0.5 h at 55 C. The conversion efficiency could reach 97.25%. Purification of transesterification products was operated at the evaporating temperature of 120 C. The content of FAME in the distillate was above 95% analysed by gas chromatography-mass spectrometry (GC-MS). (author)

[en] In this study, laponite was tested as a mud-making material for drilling fluids. Laponite is a synthetic smectite clay with a structure and composition closely resembling the natural clay mineral hectorite. Commercially available laponite was characterized by X-ray diffractometry, scanning electron microscopy and infrared spectrometry. Its dispersibility, salt resistance and high-temperature resistance were evaluated. The results showed that laponite possessed superior cation exchange capacity (140.4 mmol/100 g) with interlayer cations of Na⁺ and Li⁺. Laponite could easily be dispersed in water to yield increased viscosity with no influence from hydration time or temperature. On the other hand, laponite dispersions displayed an excellent heat resistance, with invariant apparent viscosity at high temperatures. For instance, the apparent viscosity of the 2 wt% laponite dispersion underwent changes between 22 and 24 mPa s after hot rolling at 180–240 °C for 16 h. Compared to existing mud-making materials, laponite exhibited better mud-making properties. Furthermore, laponite revealed good compatibility with other additives, and the water-based drilling fluids prepared with laponite as mud-making material showed an excellent stability at elevated temperatures and superior performance–cost ratios. Overall, these findings indicated that laponite had an excellent dispersibility at high temperatures and hence would have promising applications as high-temperature mud-making material for preparing water-based drilling fluids designed for ultra-high-temperature environments.

[en] By designing pivotal phase-only masks based on canonical catastrophe theory, finite-energy optical quinary-cusp beams are experimentally generated for the first time. Such beams are a kind of new accelerating beams having five sampling points. Their optical topological structures and propagation characteristics are investigated subsequently. Moreover, we also find that the acceleration of quinary-cusp beams can be controlled by changing the Fourier transform lens with the different local lengths. Such research results are believed to pave the way toward future potential scientific applications of quinary-cusp beams

[en] The huge amount of medical waste (MW) has caused a tough challenge to environment protection, for its serious infectious feature. At present, the incineration is the priority and main technology option for MW disposal in China. However, the medical waste incineration (MWI) is considered the major source of persistent organic pollutants (POPs), especially PCDD/Fs. In order to get an overall information of pollutants emission from MWI, a series study were conducted, involved in the generation and the components content of MW in China, the fingerprint of PCDD/Fs emission from MWI, POPs (PCDD/Fs, PCBs and HxCBz) concentration in residue ash. It is estimated that the generation of MW was 897,034 tons in 2008, plastic and rubber accounted for 24.5% of the MW weight. PCDD/Fs emission could be divided into two main groups according the fingerprint, and the ratio of PCDFs to PCDDs was mostly over 1.5. The TEQ of PCDD/Fs was over 30 times than WHO-TEQ of PCBs, and the TEQ of PCDD/Fs accounted for about 65% of the total output of PCDD/Fs in line with the UNEP default emission factors for MWI (Class 3, 63.7%). (author)

[en] Airy beams and triple-cusp beams are two kinds of accelerating beams. The propagation characteristics and internal topological structures of accelerating Airy beams are well understood because of the developed mathematical theory about Airy function. However, limited information is available about the optical characteristics of accelerating triple-cusp beams. In this work, the relationship between Airy beams and triple-cusp beams is examined theoretically and experimentally. Results reveal some important optical characteristics of triple-cusp beams based on the optical characteristics of Airy beams. These findings are expected to provide a foundation for future applications of triple-cusp beams. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

[en] We propose a kinetic aggregation model where species A aggregates evolve by the catalysis-coagulation and the catalysis-fragmentation, while the catalyst aggregates of the same species B or C perform self-coagulation processes. By means of the generalized Smoluchowski rate equation based on the mean-field assumption, we study the kinetic behaviours of the system with the catalysis-coagulation rate kernel K(i,j;l) ∝ l^ν and the catalysis-fragmentation rate kernel F(i,j;l) ∝ l^μ, where l is the size of the catalyst aggregate, and ν and μ are two parameters reflecting the dependence of the catalysis reaction on the size of the catalyst aggregate. The relation between the values of parameters ν and μ reflects the competing roles between the two catalysis processes in the kinetic evolution of species A. It is found that the competing roles of the catalysis-coagulation and catalysis-fragmentation in the kinetic aggregation behaviours are not determined simply by the relation between the two parameters ν and μ, but also depend on the values of these two parameters. When ν > μ and ν ≥ 0, the kinetic evolution of species A is dominated by the catalysis-coagulation and its aggregate size distribution a_k(t) obeys the conventional or generalized scaling law; when ν < μ and ν ≥ 0 or ν < 0 but μ ≥ 0, the catalysis-fragmentation process may play a dominating role and a_k(t) approaches the scale-free form; and in other cases, a balance is established between the two competing processes at large times and a_k(t) obeys a modified scaling law. (cross-disciplinary physics and related areas of science and technology)

[en] Highlights: • Three two-dimensional boron nitride sheets with sp² and sp hybridization are predicted. • The BN bonds in these sheets are covalent in nature but with ionic characteristics. • The band gaps of these sheets can be tunable by changing the length of sp-bonded BN linkages. Three two-dimensional (2D) single layer boron nitride sheets have been predicted based on the first-principles calculations. These 2D boron nitride sheets are comprised of equivalent boron atoms and nitride atoms with sp² and sp bond hybridization. The geometry optimization reflects that they all possess stable planar crystal structures with the space group $P\overline{6}2m$ (${\text{D}}_{3\text{h}}^3$) symmetry. The charge density distribution manifests that the B–N bonds in these boron nitride sheets are covalent in nature but with ionic characteristics. The tunable band gaps indicate their potential applications in nanoscale electronic and optoelectronic devices by changing the length of sp-bonded BN linkages.

[en] The structural, elastic, electronic, and thermodynamic properties of thermoelectric material MgAgSb in γ , β , α phases are studied with first-principles calculations based on density functional theory. The optimized lattice constants accord well with the experimental data. According to the calculated total energy of the three phases, the phase transition order is determined from α to γ phase with cooling, which is in agreement with the experimental result. The physical properties such as elastic constants, bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, and anisotropy factor are also discussed and analyzed, which indicates that the three structures are mechanically stable and each has a ductile feature. The Debye temperature is deduced from the elastic properties. The total density of states (TDOS) and partial density of states (PDOS) of the three phases are investigated. The TDOS results show that the γ phase is most stable with a pseudogap near the Fermi level, and the PDOS analysis indicates that the conduction band of the three phases is composed mostly of Mg-3s, Ag-4d, and Sb-5p. In addition, the changes of the free energy, entropy, specific heat, thermal expansion of γ -MgAgSb with temperature are obtained successfully. The obtained results above are important parameters for further experimental and theoretical tuning of doped MgAgSb as a thermoelectric material at high temperature. (paper)