Characteristics of granular boehmite and its ability to adsorb phosphate from aqueous solution

In this study, we investigated the surface properties of granulated boehmite with vinyl acetate (G-BE20) and measured the amount of phosphate it adsorbed and the effect of contact time and solution pH on the adsorption process. The specific surface area (144.9?m²/g) and the number of surface hydroxyl groups (0.88?mmol/g) of G-BE20 were smaller than those of virgin boehmite (BE), which gave a specific surface area and number of surface hydroxyl groups of 297.0?m²/g and 1.08?mmol/g, respectively. The amount of phosphate adsorbed increased with the temperature. The isotherm model of Langmuir was used to fit experimental adsorption equilibrium data for phosphate adsorption onto G-BE20. The calculated thermodynamic parameters show the spontaneous and endothermic nature of the adsorption process. The equilibrium adsorption onto G-BE20 was reached within 16?h and the amount of phosphate adsorbed was 8.4?mg/g. The kinetic mechanism of phosphate uptake was evaluated with two different models: the Largergren pseudo first- and pseudo second-order models. The data obtained showed a better fit to the pseudo second-order model (0.991) than to the pseudo first-order model (0.967), as indicated by the r values. The rate constants for the adsorption of phosphate onto G-BE20 were calculated as 0.481?1/h and 0.029?g/mg?h. The adsorption of phosphate onto G-BE20 was the maximum in the pH range 3.0-4.0.     

On-site chemical reaction lights up protein assemblies in cells

Here we report a fast and effective method to visualize interactive proteins across intact mammalian cells via on-site formation of fluorescence using instant reaction of non-fluorescent fluorescamine with primary amines on proteins. Without interference by fluorescence background, this fluorogenic labelling opens a way for selective identification of primary amine-rich interacting proteins, efficient mapping and real-time monitoring of their spatial distribution in assemblies/network, and fast differentiation of cellular types. Without adverse effect on biological functions, this labelling method also provides new insights to comprehend important aspects of cellular functions of organelles and their relation to health imperfections for disease diagnostics and imaging-guided therapy.     

Segre classes on smooth projective toric varieties

We provide a generalization of the algorithm of Eklund, Jost and Peterson for computing Segre classes of closed subschemes of projective $k$ -space. The algorithm is here generalized to computing the Segre classes of closed subschemes of smooth projective toric varieties.     

Intravoxel incoherent motion diffusion-weighted imaging in head and neck squamous cell carcinoma: Assessment of perfusion-related parameters compared to dynamic contrast-enhanced MRI

Purpose

To investigate the correlation between perfusion-related parameters obtained with intravoxel incoherent motion (IVIM) and classical perfusion parameters obtained with dynamic contrast-enhanced (DCE) magnetic resonance imaging in patients with head and neck squamous cell carcinoma (HNSCC), and to compare direct and asymptotic fitting, the pixel-by-pixel approach, and a region of interest (ROI)-based approach respectively for IVIM parameter calculation.

Materials and methods

Seventeen patients with HNSCC were included in this retrospective study. All magnetic resonance (MR) scanning was performed using a 3 T MR unit. Acquisition of IVIM was performed using single-shot spin-echo echo-planar imaging with three orthogonal gradients with 12 b-values (0, 10, 20, 30, 50, 80, 100, 200, 400, 800, 1000, and 2000). Perfusion-related parameters of perfusion fraction ‘f’ and the pseudo-diffusion coefficient ‘D*’ were calculated from IVIM data by using least square fitting with the two fitting methods of direct and asymptotic fitting, respectively. DCE perfusion was performed in a total of 64 dynamic phases with a 3.2-s phase interval. The two-compartment exchange model was used for the quantification of tumor blood volume (TBV) and tumor blood flow (TBF). Each tumor was delineated with a polygonal ROI for the calculation of f, f ? D* performed using both the pixel-by-pixel approach and the ROI-based approach. In the pixel-by-pixel approach, after fitting each pixel to obtain f, f ? D* maps, the mean value in the delineated ROI on these maps was calculated. In the ROI-based approach, the mean value of signal intensity was calculated within the ROI for each b-value in IVIM images, and then fitting was performed using these values. Correlations between f in a total of four combinations (direct or asymptotic fitting and pixel-by-pixel or ROI-based approach) and TBV were respectively analyzed using Pearson's correlation coefficients. Correlations between f ? D* and TBF were also similarly analyzed.

Results

In all combinations of f and TBV, f ? D* and TBF, there was a significant correlation. In the comparison of f and TBV, a moderate correlation was observed only between f obtained by direct fitting with the pixel-by-pixel approach, whereas a good correlation was observed in the comparisons using the other three combinations. In the comparison of f ? D* and TBF, a good correlation was observed only with f ? D* obtained by asymptotic fitting with the ROI-based approach. In contrast, moderate correlations were observed in the comparisons using the other three combinations.

Conclusion

IVIM was found to be feasible for the analysis of perfusion-related parameters in patients with HNSCC. Especially, the combination of asymptotic fitting with the ROI-based approach was better correlated with DCE perfusion.     

Does Σ–Σ–α Form Quasi-Bound States?

For the Σ–Σ–α system we theoretically look into the possible existence of a quasi-bound state in the framework of Faddeev calculations. We are particularly interested in the state of total iso-spin T=2, because there is no strong conversion between Ξ–N–α and ${\Lambda-\Lambda-\alpha}$ . An analytic continuation using the point method is applied to search the eigenvalue in the complex energy plane. In our results the Σ–Σ–α three-body system has two quasi-bound states (J ^π  = 0⁺) where, depending on the potential parameters in the Nijmegen NSC97 model potential, the energy ranges between ?1.4 and ?2.4 MeV and the level width is about 0.4 MeV for the ground state. In addition, we obtained the excited state at ?0.15 MeV (width 4 MeV).     

Propagation property for anisotropic nonlinear diffusion equation with convection

We consider propagation property for anisotropic diffusion equation with convection in 2 dimension,

t_∂(um)−x_1∂(|x_1∂u|^p₁−1x_1∂u)−x_2∂(|x_2∂u|^p₂−1x_2∂u)+uα−1x_1∂u=0,     

Designer multi-functional comb-polymers for surface engineering of quantum dots on the nanoscale

Synthesis, characterization and cell-biomarker applications for a novel series of comb-copolymers featuring hydrophobic amide side groups, carboxylates and other functionalities such as polymerizable side chains and PEG oligomers are reported. When used as polymer ligand shell for trioctylphosphine oxide (TOPO) coated quantum dots (QDs) these copolymers effectively solubilise CdSe/ZnS QDs in water. A systematic study was carried out to find the relation between the molecular structure of the copolymers, their ability to coat the QDs, and to suspend the nanocrystals in water. To demonstrate potential applications, highly luminescent QD/polymer assemblies were internalized into living and fixed cells.     

Some self-consistent perturbation calculations of 1J(CC)

Self-consistent perturbation calculations of 70 ¹J(CC) values are reported within the INDO framework. A least-squares agreement between the calculated and observed couplings, for a variety of bond multiplicities, provides values of 13.503 au^?6 and 5.072 au^?6 for (S_C²(O))² and 〈r^?3〉_C², respectively. The non-contact terms are found to be important in cases of multiple bonding.     

Laser mechanisms and processes in the p-GE far IR laser

Laser mechanisms in the p-Ge far IR laser are identified and models presented to make laser line assignments in the three laser spectral regions: (A) multiple frequencies non-tunable with E and B, (B) multiple frequencies tunable with B, and (CR) single cyclotron frequencies tunable with B. Brief reviews of the classical and quantum theories of the p-Ge laser are given to support and explain the laser models.