RESUMEN

The collaborative utilization of solid waste through cement kiln represents a highly effective approach in the current era for harnessing solid waste resources. In this paper, density functional theory simulations is used to predict the substitution tendency of tungsten (W) in Ordinary Portland cement (OPC) clinker. By employing experimental design, X-ray diffraction testing, and element distribution spectrum analysis, the doping preference of W ions in OPC clinker was comprehensively investigated. The findings demonstrate that a minor fraction of WO3 firstly infiltrates C4AF through the substitution of Fe atoms, whereas the majority of WO3 infiltrates C3S and C2S secondly by substituting Si atoms, with negligible infiltration observed in C3A finally. The substitution of Fe with W exhibits a lower formation energy compared to other ions, thereby indicating its preference for the formation of solid solutions in C4AF. This preference is primarily determined by the overlapping distribution of WO and FeO bond order-bond length and their similar electron contributions in spatial distribution. However, it should be noted that the newly formed WO bond has weaker strength than the FeO bond, which may explain the limited solubility of W in C4AF. The in-depth investigation of these fundamental issues is expected to offer an effective approach for enhancing solubility of W in OPC clinker through increasing content of C4AF and silicate minerals, thereby providing valuable guidance for synthesizing OPC clinker using W-bearing solid wastes.

RESUMEN

We present two optical breast atlases for optical mammography, aiming to advance the image reconstruction research by providing a common platform to test advanced image reconstruction algorithms. Each atlas consists of five individual breast models. The first atlas provides breast vasculature surface models, which are derived from human breast dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data using image segmentation. A finite element-based method is used to deform the breast vasculature models from their natural shapes to generate the second atlas, compressed breast models. Breast compression is typically done in X-ray mammography but also necessary for some optical mammography systems. Technical validation is presented to demonstrate how the atlases can be used to study the image reconstruction algorithms. Optical measurements are generated numerically with compressed breast models and a predefined configuration of light sources and photodetectors. The simulated data is fed into three standard image reconstruction algorithms to reconstruct optical images of the vasculature, which can then be compared with the ground truth to evaluate their performance.

Asunto(s)

RESUMEN

A regio-, chemo-, and enantioselective nickel-catalyzed hydrocyanation of 1,3-dienes is reported. The key to the success of this asymmetric transformation is the use of a specific multichiral diphosphite ligand. In addition to aryl-substituted 1,3-dienes, highly challenging aliphatic 1,3-diene substrates can also be preferentially converted to the corresponding 1,2-adducts in decent yields with the highest enantioselectivities to date.

RESUMEN

The Markovnikov hydrocyanation of α-substituted styrenes enables the synthesis of tertiary benzylic nitriles under nickel catalysis. The Lewis-acid-free transformation features an unprecedented functional groups tolerance, including the -OH and -NH2 groups. A broad range of tertiary benzylic nitriles were obtained in good to excellent yields. In addition, an asymmetric version of this reaction was preliminarily investigated.

RESUMEN

The objective of this study was to evaluate a novel oil-based suspension as a potential parenteral drug delivery system for drugs with poor water solubility. Most of the new active pharmaceutical ingredients are weak acid or basic drugs with pH-dependent solubility. To limit this dependence, use of micro-environmental pH-modifying solid dispersions (micro pHm SD) has been proved to increase the bioavailability of these drugs. Toltrazuril (TOL), a weakly acidic drug with poor aqueous and pH-dependent solubility, was studied as a model drug. Recently, studies on TOL with focus on the parenteral injection are rarely to find in the literature. A novel parenteral oil-based TOL suspension was prepared containing TOL micro pHm SD (TSD) powders suspended in oil-based vehicles and the optimal formulation was screened. The stability of this formulation was assessed considering particle size distribution, settling volume ratio, redispersibility, thermal stability, and drug content. The optimized white oil-based TOL pHm SD suspension (W-TSDS) showed significant improved stability and shear-thinning behavior. In particular, fumed silica as suspending agent positively influenced the physical stability of the formulation. Furthermore, W-TSDS showed good injectability using 21 G needles and more rapid and sustained drug release compared to TSD powders in vitro. In the in vivo safety evaluation, W-TSDS showed good histocompatibility in rabbits injected subcutaneously or intramuscularly. We believe these findings provide an alternative choice of dosage form for the delivery of new active pharmaceutical ingredients.

Asunto(s)

RESUMEN

Drugs with pH-dependent solubility that have poor water solubility can be identified in the drug discovery pipeline. Some of them have poor oral absorption, which can result in insufficient efficacy. Micro-environmental pH-modifying solid dispersion (micro pHm SD) is a promising approach to overcome the poor oral absorption of these drugs. In the present study, toltrazuril (TOL), a weakly acidic drug with poor aqueous and pH-dependent solubility, was used as a model drug. Using micro pHm SD, a novel oral oil-based suspension of TOL SD (TSDS) was developed, and the stability of this formulation was evaluated based on particle size, settling volume ratio, redispersibility, thermal stability, and drug content. The optimized soybean oil-based TSDS (S-TSDS) had high physicochemical stability and good histocompatibility with common inflammatory reactions. The results of the in vitro dissolution analysis showed that S-TSDS rapidly and markedly released the drug and provided higher efficacy and longer persistence against coccidiosis (above 90.9%) in rabbits. This technique could increase the oral absorption and bioavailability of new drug candidates.

Asunto(s)