A novel magnetic extractant, PEG 4000 modified Fe3O4nanomaterial that coated with dianionic amino acid ionic liquid (Fe3O4@PEG@DAAAIL), was successfully synthesized and characterized. X-ray ...diffraction (XRD), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA) and zeta potentials were used to confirm that the novel nanocomposite was successfully synthesized. Subsequently, the prepared Fe3O4@PEG@DAAAIL nanocomposite was used as the extractant for trypsin coupled with magnetic solid-phase extraction (MSPE). The concentrations of trypsin in the supernatant were detected by UV–vis spectrophotometer at 278nm. The extraction ability turned out to be better than the other four kinds of extractants prepared in this work. Furthermore, the influence of a series of factors, such as extraction time and temperature, initial trypsin concentration, the value of pH and ionic strength, was systematically investigated. Under the optimal extraction condition, the extraction capacity for trypsin could reach up to 718.73mg/g, absolutely higher than that of other adsorbents reported. This satisfactory extraction capacity could be maintained unchangeable after at least eight days, and kept over 90% of initial extraction capacity after eight recycles. What's more, the activity of trypsin after extraction retained 92.29% of initial activity, verifying the biocompatibility of the prepared extractant. Finally, the developed Fe3O4@PEG@DAAAIL-MSPE method was successfully applied to the real sample analysis with satisfactory results. All of above proves the potential value of Fe3O4@PEG@DAAAIL-MSPE in the analysis of biomass.
Display omitted
•A dianionic amino acid ionic liquid-based MSPE method for trypsin has been developed.•Fe3O4@PEG@DAAAIL nanocomposite possesses high extraction capacity for trypsin.•The activity of trypsin was not destroyed by Fe3O4@PEG@DAAAIL-MSPE method.•The new procedure was successfully applied to the analysis of real sample.
Scattering phase function of aerosol particles is crucial to the accurate estimation of aerosol direct radiative forcing, and is also of great interest in the field of remote sensing. One feasible ...and promising way to obtain scattering phase function on a long-term scale with satisfying temporal resolution is based upon the particle size distribution (PSD) and the refractive index (m = n + ik) simultaneously retrieved from multi-wavelength multi-angle scattering detected by Aurora 4000, a commercially available and easily operated, as well as lab- and field-deployable instrument. In this study, a retrieval algorithm was specifically developed according to the characteristics of Aurora 4000 measurements, using the regularization method. The algorithm was systematically evaluated for its applicability, capability and limitation by a series of designed numerical experiments, considering both monomodal and bimodal log-normal distributions with various settings of parameters and different m, in order to be prepared for its application in field studies. The retrieval algorithm has exhibited a successful performance in deriving the PSDs and the real part of the refractive index (n) without a priori assumptions about the shape of the PSDs and the value of n, and consequently in obtaining scattering phase function, for aerosol particles from purely scattering to slightly absorbing (the imaginary part of the refractive index k ≤ 0.01) both without and with assumed measurement errors (when ±ψs≤±3%). Under such circumstances, relative errors in retrieved effective diameter (De), total surface area concentration (Sa), total volume concentration (Va) are almost within ±20%, relative errors in retrieved total number concentration (Na) stay roughly within ±50%, and absolute errors of n are well within ±0.02. Moreover, relative errors in backscattering ratio (BSR) and the defined parameter to describe relative errors in scattering phase function (δP), as good indicators for demonstrating how well scattering phase function can be captured, averagely locate within ±20% and ±10%, respectively. In contrast, relative errors in the widely used parameters of the asymmetry parameter (g) and hemispheric backscattering ratio (HBSR) remain still quite small even when considerable deviations can be observed in the forward and backward scattering regimes. Hopefully, when applied in field studies in the next step, the retrieval algorithm established in this study will improve our knowledge and understanding on angular scattering properties of ambient aerosol particles, as well as the associated impacts on aerosol direct radiative forcing.
•An algorithm is developed for Aurora 4000 to retrieve particle size distribution and estimate refractive index.•The algorithm is systematically evaluated by a series of numerical experiments.•Aerosol scattering phase function is obtained from retrieved parameters.
We present new equations of state (EOSs) for hydrogen and helium covering a wide range of temperatures from 60 K to 10 super(7) K and densities from 10 super(-10) g cm super(-3) to 10 super(-3) g cm ...super(-3). They include an extended set of ab initio EOS data for the strongly correlated quantum regime with an accurate connection to data derived from other approaches for the neighboring regions. We compare linear mixing isotherms based on our EOS tables with available real mixture data. A first important astrophysical application of this new EOS data is the calculation of interior models for Jupiter and comparison with recent results. Second, mass-radius relations are calculated for Brown Dwarfs (BDs) which we compare with predictions derived from the widely used EOS of Saumon, Chabrier, and van Horn. Furthermore, we calculate interior models for typical BDs with different masses, namely, Corot-3b, Gliese-229b, and Corot-15b, and the giant planet KOI-889b. The predictions for the central pressures and densities differ by up to 10% dependent on the EOS used. Our EOS tables are made available in the supplemental material of this paper.
Although archaeological findings show the synchronous collapses of major well-documented Chinese Neolithic cultures around 4000 cal. yr BP, the driving mechanism for the phenomenon is still unclear ...and debatable. Spatial climatic features in China spanning this time period suggest a generally cold-dry setting. This is evidenced by 130 well-dated geological records at 97 sites located in climatically and topographically diverse regions, with occurrences of some extreme hydrological events like severe floods in the Chinese Loess Plateau, and in basins of the lower Yellow River and the middle-to-lower Yangtze River. The weakening of the Asian Summer Monsoon (ASM) since the mid-Holocene would have made Neolithic subsistence living unfavourable by decreasing the warmth and wetness in arid and semi-arid regions. However, it might not have been the sole factor that destroyed the Neolithic cultures in the vast territories of China ca. 4000 cal. yr BP. Environmental alterations in the major cultural territories of China reacted in response to precipitation anomalies caused by high variability of the ASM and the westerlies, which were modulated by centennial- to inter-annual- scale driving factors such as solar insolation, the North Atlantic Oscillation (NAO), the Pacific Decadal Oscillation (PDO) and El Niño-Southern Oscillations (ENSO). This most likely accounted for the nearly synchronous Chinese Neolithic cultural collapses.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted) Because of their large numbers, low-mass stars may be the most abundant planet hosts in our Galaxy. Furthermore, terrestrial planets ...in the habitable zones (HZs) around M-dwarfs can potentially be characterized in the near future and hence may be the first such planets to be studied. Recently, Dressing & Charbonneau used Kepler data and calculated the frequency of terrestrial planets in the HZ of cool stars to be ... per star for Earth-size planets (0.5-1.4 R sub(Hamiltonoperator)). However, this estimate was derived using the Kasting et al. HZ limits, which were not valid for stars with effective temperatures lower than 3700 K. Here we update their result using new HZ limits from Kopparapu et al. for stars with effective temperatures between 2600 K and 7200 K, which includes the cool M stars in the Kepler target list. The new HZ boundaries increase the number of planet candidates in the HZ. Assuming Earth-size planets as 0.5-1.4 R sub(Hamiltonoperator), when we reanalyze their results, we obtain a terrestrial planet frequency of ... super()and ... planets per M-dwarf star for conservative and optimistic limits of the HZ boundaries, respectively. Assuming Earth-size planets as 0.5-2 R sub(Hamiltonoperator), the frequency increases to ... per star for the conservative estimate and to ... per star for the optimistic estimate. Within uncertainties, our optimistic estimates are in agreement with a similar optimistic estimate from the radial velocity survey of M-dwarfs (...)- So, the potential for finding Earth-like planets around M stars may be higher than previously reported.
An experimental study into twin screw granulation (TSG) has been performed using a design of experiments (DoE) approach. The properties of the produced granules are compared to those reported ...previously from a range of continuous and batch granulation processes. The effect of processing parameters such as speed, temperature and binder content on granule strength and structure are analysed. Seeded granule structures were found to be present in all but one type of granulator (Extrudomix) and longer residence times were found to lead to maximum seeded structures with a batch Cyclomix granulator. Granule crushing strengths were found to be higher in TSG than all other continuous equipment and the optimum condition for the formation of stronger granules with the lowest variation was around 65.4 °C. Overall, an equipment-specific DoE approach was shown to be a useful method to establish the relationship between process parameters, structure and properties.
Display omitted
•Equipment specific DoE gives better understanding of process-parameter effect.•Long residence times with enough binder enables denser and stronger granules.•Higher binder ratio at the same temperature improves strength.•Temperature and binder ratio strongly influence granule properties in TSE.•Stronger granules are formed by less viscous binder at higher temperatures.
Objective: The aim of the work was to enhance the dissolution rate of rivaroxaban by preparing its solid dispersions (SDs) using hydrophilic carrier PEG 4000.
Methods: The SDs of rivaroxaban with PEG ...4000 were prepared at 1:1, 1:2 and 1:3 w/w ratios by physical mixing, melting and solvent evaporation techniques. The prepared solid dispersions were characterized by Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC).
Results: Both the solubility and dissolution rate of the drug in these formulations were increased. The used hydrophilic carriers showed a more than two-fold increase in dissolution rate in their prepared solid dispersions by melting or solvent evaporation techniques. The pure drug rivaroxaban as the pure drug shows a dissolution rate of nearly 39 % after 60 m, whereas the solid dispersions by melting or solvent evaporation showed 90% of dissolution after 60 m. The FTIR spectroscopic and DCS thermal studies showed the compatibility of rivaroxaban and the absence of well-defined drug polymer interactions, though the shift in peaks was observed due to the formation of new bonds.
Conclusion: Formulation of solid dispersions of drug with hydrophilic carriers is a successful approach for solubility or dissolution rate enhancement of low soluble drug(s). In this work for solubility enhancement of rivaroxaban the hydrophilic carrier PEG 4000 showed significant solubility enhancement.
The aim of this study was to determine the effect of varying excipient content on the formation and physical properties of 3 D printed tablets. Fifteen different excipient preparations were formed ...into tablets with radii of 5 mm and thickness of 2 mm, using binder jetting (BJ). The tablets were analyzed by assessing visual and microstructural appearance, friability, hardness, and disintegration time. We found that filling agents with high water solubility (e.g. D-sucrose), binding agents with a high viscosity in solution (e.g. polyethylene glycol 4000) and moistening agent with higher water content can increase the bonding strength and hardness of the 3 D printed tablets and prolonged their disintegration time. This work has demonstrated that the type of excipient and its concentration affects the properties of the 3 D printed tablet. This article may be used as a guide for elucidation of the effects of using conventional tablet excipients in the field of 3 D printed pharmaceuticals. The present work should enable the identification of excipients that satisfy requirements, reduce analysis time, and improve efficiency.
This article compares the effect of different surfactants on foam stability and determines the foam decay relationship, so that the suitability of surfactants in a clinical setting can be evaluated.
...Five different surfactants were used to prepare sclerosing foam at room temperature using a liquid:gas ratio of 1:4 in vitro. Foam decay experiments were performed for each sample using a laboratory-made foaming apparatus, and the process was recorded using a video camera. The stability indices used included the drainage time, drainage rate, half-life, foam half-life volume, surfactant stability index, and foaming index.
The sodium morrhuate foam was relatively more stable than the polidocanol foam, but exhibited weak foaming. After the addition of the surfactants, the foam half-life was less than 300 seconds. The effect of the surfactants on the stability of the sodium morrhuate foam was more pronounced. The surfactant stability indices could be arranged as follows: poloxamer 188 > Tween 80 > macrogol 4000 > propanediol > lecithin. However, the differences in the foaming indices were small.
Of the five surfactants tested, poloxamer 188 has best performance to enhance sclerosing foam stability. The addition of the surfactants improved the stability of the sclerosing foams. It was observed that the relationships between the foam half-life and the surfactant stability index and the surfactant concentration follow the power law.
Improving foam stability would not only improve the efficacy of foam sclerotherapy, but would also increase patient safety. Therefore, we investigated the effects of five commonly used surfactants on the stability of foams of two drugs used widely for treating varicose diseases. A new test scheme for evaluating the foaming characteristics and stability of two commonly used drugs was proposed. The results of this study should aid the preparation and use of sclerosing foams in clinical applications as well as further our understanding of the nature of the foams themselves and, thus, provide a more grounded theoretical and experimental basis for their use in the treatment of varicose diseases.
Display omitted
•Thermodynamic properties of KBr in PEG 4000 + H2O were studied at (288.2, 298.2, and 308.2) K.•Experimental data were fitted to the extended Debye-Hückel and Pitzer models.•Good ...agreement between experimental and correlated data was obtained by both models.•Activity coefficients, the standard free energy of transference, and primary hydration number were reported.
The goal of this research is to evaluate the mean ion activity coefficients (γ±) of the mixtures containing KBr + PEG 4000 + H2O (PEG stands for poly(ethylene glycol)) as well as some other thermodynamic quantities including solvent osmotic coefficients (φ), excess Gibbs energies (GE), standard Gibbs energies of transference (ΔGt0), and primary hydration number (nhydr). The experiment was employed by potentiometric measurement using the cell with two ion-selective electrodes (abbreviated as ISE) at (288.2, 298.2, and 308.2) K, and the mass fraction of PEG 4000 ranged from w = (0 to 0.20) with an increment of 0.05. The type of the cell is as follows:
K–ISE | KBr (m), PEG 4000 (w), H2O (1-w) | Br–ISE.
Nernst's equation was used to combine the Debye-Hückel and Pitzer models with potentiometric values. Pitzer ion interaction parameters (β0, β1, and Cφ) and Debye-Hückel model parameter (a) were evaluated. Moreover, the Bjerrum parameter (q) was calculated.
PDF
