Calcite–oleate–oxalate interaction in calcite flotation system

Calcite is considered a semi-soluble mineral in flotation. Its solubility in acids plays a major role in its floatability. In this study, micro-flotation experiments are conducted to investigate the interaction of calcite particles with potassium oleate (KOl). Potassium oxalate is used as a depressant in the presence of HC1 or H₂SO₄ as pH modifiers. Flotation experiments indicated that calcite behaves differently in the presence of HCl and H₂SO₄. The calcite floatability is higher in the case of HCl. The different behavior is more obvious in the presence of oxalate. The depressing effect of oxalate is more pronounced in the case of using H₂SO₄ as a pH modifier. In addition, the sensitivity of calcite flotation to pH goes back to the amount of free Ca-ions in the solution. Ionic equilibrium of the dissolved ionic species is proved to play a crucial role in either enhancing or reducing the oleate adsorption, which in turn affects the calcite floatability.     

Flexibility and binding affinity in protein–ligand,protein–protein and multi-component protein interactions: limitations of current computational approaches

The recognition process between a protein and a partner represents a significant theoretical challenge. In silico structure-based drug design carried out with nothing more than the three-dimensional structure of the protein has led to the introduction of many compounds into clinical trials and numerous drug approvals. Central to guiding the discovery process is to recognize active among non-active compounds. While large-scale computer simulations of compounds taken from a library (virtual screening) or designed de novo are highly desirable in the post-genomic area, many technical problems remain to be adequately addressed. This article presents an overview and discusses the limits of current computational methods for predicting the correct binding pose and accurate binding affinity. It also presents the performances of the most popular algorithms for exploring binary and multi-body protein interactions.     

Control of electron–lattice interaction in organic nanoclusters

In this study we demonstrate that the electron–lattice interaction (ELI) could be controlled by changing exciton delocalization length in ordered organic nanoclusters called J-aggregates. Particularly it could be done via the J-aggregates solvate shell manipulation using surfactants. The strong correlation between the J-aggregates luminescence quantum yield and the ELI strength has been reviled that allows us to consider the exciton self-trapping as the main mechanism of the J-aggregates luminescence losses.     

Synthesis of protein–gold nanoparticle hybrid and gold nanoplates in protein aggregates

A straightforward and economically viable approach was developed to biomimetic synthesis of gold nanocrystals by using casein micelles (CMs) without additional reductant. The UV–vis, TEM, SAED, FTIR, DLS and XRD techniques were employed to systematically characterize Au nanocrystals synthesized. Isotropic gold nanoparticle (GNP) and gold nanoplates in good yields (up to 90%) with different sizes can be obtained easily by adjusting the experimental condition. Spherical nanoparticles were obtained with tunable mean sizes at higher pH and casein concentrations. The high colloidal stability of the spherical GNP is attributed to the formation of CM/GNP hybrid under some experimental condition. At lower pH, reaction temperature and casein concentrations, single-crystalline gold nanoplates in good yields (up to 90%) are obtained. The growth of these nanostructures is attributed to an interplay between the faceting tendency of the protein molecules/micelles and the growth kinetics. More importantly, the morphological evolution of large gold nanoplates at different reaction times has been followed, and compared with some earlier protein systems, different formation mechanisms in casein micelles are obtained. The results demonstrate that both the property of individual protein molecules and protein aggregates play important roles in controlling the formation of gold nanocrystals by using amphiphilic protein.     

Guest–host interaction in ferroelectric liquid crystal–nanoparticle composite system

The present paper deals with the characterization of a ferroelectric liquid crystal–nanoparticle (FLC–NP) composite system. The dielectric, electrical and polarization property of the FLC–NP composite system have been studied as a function of temperature and frequency. Ferroelectric Cu-doped ZnO (Cu–ZnO) nanoparticles have been added to the pure ferroelectric liquid crystal (FLC) Felix 17/100. The nanoparticles are bigger in size as compared to FLC molecules; therefore, they distort the existing geometry of FLC matrix and set up an antiparallel correlation with the dipole moments of the host FLC molecules. This antiparallel correlation of guest–host geometry reduces the net ferroelectricity of the composite system and modifies all the physical properties of the pure FLC. The change in properties has been analysed and explained in the light of guest–host interaction.     

Dynamic analysis of dam–reservoir-foundation interaction in time domain

In this paper, a time domain dynamic analysis of the dam–reservoir-foundation interaction problem is developed by coupling the dual reciprocity boundary element method (DRBEM) for the infinite reservoir and foundation domain and the finite element method for the finite dam domain. An efficient coupling procedure is formulated by using the substructuring method. Sharans boundary condition at the far end of the infinite fluid domain is implemented. To verify the proposed scheme, numerical examples are carried out and compared with available exact solutions and finite–finite element coupling results for the problem of the dam–reservoir interaction. Finally, a complete dam–reservoir-foundation interaction problem is solved and its solution is compared with previously published results.The author is thankful to the anonymous reviewer of this paper for his suggestions and comments, which improved considerably the present paper.     

Prediction of human protein–protein interaction by a mixed Bayesian model and its application to exploring underlying cancer-related pathway crosstalk

Protein–protein interaction (PPI) prediction method has provided an opportunity for elucidating potential biological processes and disease mechanisms. We integrated eight features involving proteomic, genomic, phenotype and functional annotation datasets by a mixed model consisting of full connected Bayesian (FCB) model and naive Bayesian model to predict human PPIs, resulting in 40 447 PPIs which contain 2740 common PPIs with the human protein reference database (HPRD) by a likelihood ratio cutoff of 512. Then we applied them to exploring underlying pathway crosstalk where pathways were derived from the pathway interaction database. Two pathway crosstalk networks (PCNs) were constructed based on PPI sets. The PPI sets were derived from two different sources. One source was strictly the HPRD database while the other source was a combination of HPRD and PPIs predicted by our mixed Bayesian method. We demonstrated that PCNs based on the mixed PPI set showed much more underlying pathway interactions than the HPRD PPI set. Furthermore, we mapped cancer-causing mutated somatic genes to PPIs between significant pathway crosstalk pairs. We extracted highly connected clusters from over-represented subnetworks of PCNs, which were enriched for mutated gene interactions that acted as crosstalk links. Most of the pathways in top ranking clusters were shown to play important roles in cancer. The clusters themselves showed coherent function categories pertaining to cancer development.     

Fabrication and properties of novel composites in the system Al–Zr–C

Composite bodies in the system Al–Zr–C, with about 95% relative density, were obtained by heating the compact body of powder mixture consisting of Al and ZrC (5 : 1 mol %) in Ar at 1100–1500°C for various lengths of time. Components of the material heated at more than 1200°C were Al, Al3Zr, ZrC and AlZrC2. The Al3Zr exhibited plate-like aggregation, and its size increased with increasing temperature. In the material heated at 1500°C for 1 h, the largest plate-like Al3Zr aggregation was 2000 m long and 133 m thick. Then the AlZrC2 was present as well-proportioned hexagonal platelet particles with a 8–9 m diameter and a 1–2 m thickness in the interior of the plate-like Al3Zr aggregation and Al matrix phase. The average three-point bending strength of the bodies was 140–190 MPa, and the maximum strength was 203 MPa in the body heated at 1300°C for 1 h. The body heated at 1500°C for 1 h showed high oxidation resistivity to air up to 1000°C.     

3D mass-redistributed finite element method in structural–acoustic interaction problems

A 2D mass-redistributed finite element method (MR-FEM) for pure acoustic problems was recently proposed to reduce the dispersion error. In this paper, the 3D MR-FEM is further developed to solve more complicated structural–acoustic interaction problems. The smoothed Galerkin weak form is adopted to formulate the discretized equations for the structure, and MR-FEM is applied in acoustic domain. The global equations of structural–acoustic interaction problems are then established by coupling the MR-FEM for the acoustic domain and the edge-based smoothed finite element method for the structure. The perfect balance between the mass matrix and stiffness matrix is able to improve the accuracy of the acoustic domain significantly. The gradient smoothing technique used in the structural domain can provide a proper softening effect to the “overly-stiff” FEM model. A number of numerical examples have demonstrated the effectiveness of the mass-redistributed method with smoothed strain.     

Electron–vibrational interaction in the 5d states of Ce ions in halosulphate phosphors

Using the literature data on excitation and luminescence spectra of Ce³⁺ ions in NaMgSO₄F, Na₃SO₄F, and KZnSO₄Cl halosulphate phosphors [S.C. Gedam, S.J. Dhobe, S.V. Moharil, J. Lumin. 126 (2007) 121], we performed comparative studies of electron–vibrational interaction (EVI) of the cerium 5d states with host lattices. The main EVI parameters, such as the Huang-Rhys factor, effective phonon energy, and zero-phonon line position, were estimated and reported for these systems for the first time. The obtained results were checked by modeling the Ce³⁺ 5d–4f emission line shapes; good agreement with experimental spectra confirms validity of the performed analysis.     

Synthesis and in vitro characterization of a novel PAA–ATP conjugate

The objective of this study was to improve the multifunctional properties of poly(acrylic acid) (PAA) by covalent attachment of 4-aminothiophenol (ATP) to its backbone. The permeation enhancing effect of PAA–ATP together with glutathione was evaluated in Ussing-type chambers using fluorescein isothiocyanate dextran as model compound. The mucoadhesive properties were evaluated in vitro on freshly excised porcine intestinal mucosa through the rotating cylinder method. The resulting conjugates PAA–ATP1 and PAA–ATP2 displayed 168 ± 35 and 426 ± 55 μmol immobilized free thiol groups per gram polymer, respectively. In addition, 279 ± 28 and 139 ± 22 μmol disulfide bonds per gram polymer, respectively, were identified on PAA–ATP1 and PAA–ATP2. Within disintegration studies in aqueous buffer solution, the modified polymers showed improved cohesive properties. Because of the immobilization of ATP, the swelling of PAA–ATP1 and PAA–ATP2 improved 12.0- and 17.8-fold, respectively. The adhesion times of the conjugates PAA–ATP1 and PAA–ATP2 were more than 20- and 30-fold increased in comparison to unmodified PAA. Furthermore, conjugates PAA–ATP1 and PAA–ATP2 exhibited a 1.86- and 2.07-fold higher permeation enhancing effect, respectively, over unmodified PAA. According to these results, PAA–ATP conjugates represent a very promising novel type of thiomer for the development of various mucoadhesive drug delivery systems.     

Using design equations to identify sources of complexity in human–machine interaction

A coupled design is generally more difficult to use than an uncoupled design. It should therefore be replaced by an uncoupled design. The problem described in this paper is to identify sources of couplings and propose new design parameters that uncouple the design. A method based on Suh's axiomatic design (AD) was developed. There are two axioms in AD. The first axiom proclaims that design parameters should be selected so that functional requirements become independent. Based on this, a method for Human Factors Design was devised. It is called Design Equations for Systems Analysis (DESA). Several case studies of human factors design problems were analysed: a refrigerator, hand tools and a driver's compartment. As demonstrated in the case studies, DESA is useful for analysis of existing design solutions as well as for synthesis of new design alternatives. The second axiom in AD aims at minimizing information in design. It should be noted that this is in agreement with Hick's law and Fitts’ law. The calculation of information or entropy in design was demonstrated for an adjustable workstation. The second axiom was adapted to human factors design by taking into account the variability of human attributes, in this case anthropometric measures. If the manufacturer's supplied adjustability range and the users’ desired range are known, the entropy or information of an adjustable workstation can be quantified. In comparing several workstations, the workstation with the least information should be selected.     

Phosphor–silicone interaction effects in high power white light emitting diode packages

As a widespread application of high power phosphor-converted white light emitting diodes (pc-WLEDs) with long lifetime and color-consistence, the highly reliable phosphor/silicone composite, one of core materials used for light-conversion, working under severe operation conditions has become increasingly necessary. This paper selects three widely used monochromatic phosphors (Aluminates, Silicates and Nitrides based) as well as a pristine silicone to determine the potential interaction effects in their phosphor/silicone composites operated under different environments. Firstly, the transient thermal quenching and long-term high temperature ageing tests are used to investigate the thermal stabilities of both monochromatic phosphor powders and phosphor/silicone composites. Furthermore, the degradation mechanisms of phosphor/silicone composites aged under the high temperature & blue light exposure and high temperature & high humidity conditions are studied by considering the interaction effect. The results show that: (1) the thermal stabilities of different phosphors are different and the phosphor/silicone composites have more severe thermal quenching effects than those of their corresponding phosphor powders, but with the similar degradation trends; (2) the blue light irradiation can deteriorate silicone which is related to the photolysis effect; (3) the moisture can accelerate the degradation of phosphor/silicone composites because the change of pH condition, owing to the dissolution of phosphor powders in moisture, can degrade both phosphors and silicone.     

Characterization of novel borides in Ti–Nb–Zr–Ta + 2B metal-matrix composites

Metal-matrix composites consisting of a complex quaternary Ti-35Nb-7Zr-5Ta alloy reinforced by borides have been successfully deposited from a powder feedstock consisting of a blend of elemental titanium, niobium, zirconium, tantalum, and, titanium diboride (TiB₂) powders, using the laser engineered net-shaping (LENS?)¹ process. The microstructures of the as-deposited composites have been characterized using scanning electron microscopy, orientation microscopy, and, transmission electron microscopy. Both primary and eutectic boride precipitates, exhibiting the orthorhombic B27 structure, are observed in these as-deposited composites. The complex primary borides exhibit an unusual compositional variation within the same precipitate, which has been investigated in detail using site-specific characterization with a transmission electron microscope. The ability to form near-net shape components using the Laser Engineered Net Shaping process makes these laser-deposited composites promising candidates for wear-resistant applications in biomedical implants.     

Osseointegration behavior of novel Ti–Nb–Zr–Ta–Si alloy for dental implants: an in vivo study

This study aimed to evaluate the effects of Ti–Nb–Zr–Ta–Si alloy implants on mineral apposition rate and new BIC contact in rabbits. Twelve Ti–Nb–Zr–Ta–Si alloy implants were fabricated and placed into the right femur sites in six rabbits, and commercially pure titanium implants were used as controls in the left femur. Tetracycline and alizarin red were administered 3 weeks and 1 week before euthanization, respectively. At 4 weeks and 8 weeks after implantation, animals were euthanized, respectively. Surface characterization and implant-bone contact surface analysis were performed by using a scanning electron microscope and an energy dispersive X-ray detector. Mineral apposition rate was evaluated using a confocal laser scanning microscope. Toluidine blue staining was performed on undecalcified sections for histology and histomorphology evaluation. Scanning electron microscope and histomorphology observation revealed a direct contact between implants and bone of all groups. After a healing period of 4 weeks, Ti–Nb–Zr–Ta–Si alloy implants showed significantly higher mineral apposition rate compared to commercially pure titanium implants (P?<?0.05), whereas there was no significant difference between Ti–Nb–Zr–Ta–Si alloy implants and commercially pure titanium implants (P?>?0.05) at 8 weeks. No significant difference of bone-to-implant contact was observed between Ti–Nb–Zr–Ta–Si alloy implants and commercially pure titanium implants implants after a healing period of 4 weeks and 8 weeks. This study showed that Ti–Nb–Zr–Ta–Si alloy implants could establish a close direct contact comparedto commercially pure titanium implants implants, improved mineral matrix apposition rate, and may someday be an alternative as a material for dental implants.