Correlative microscopy of detergent granules

The microstructure of detergent products for textile cleaning determines to a large extent the physical properties of these products. Correlative microscopy was used to reveal the microstructure by reconciling images obtained by scanning electron microscopy with energy dispersive X-ray analysis, X-ray microtomography and Fourier transform infrared microscopy. These techniques were applied on the same location of a subsample of a spray-dried detergent base powder embedded in polyacrylate. In this way, the three-dimensional internal and external structure of detergent granules could be investigated from milli to nano scale with detailed spatial information about the components present. This will generate knowledge how to design optimal microstructures for laundry products to obtain product properties demanded by the market. This method is also very useful for other powder systems used in a large variety of industries (e.g. for pharmaceutical, food, ceramic and metal industries).     

Real-time mapping of moisture migration in cereal based food systems with Aw contrast by means of MRI

The redistribution of water in prototype food systems, comprising phases with contrasting water activity (A_w), was investigated. To accomplish this task, MRI techniques adapted to migration rate were used. RARE and SPI measuring methods were used to monitor water redistribution in crunchy inclusions in water and biscuit shells with apple filling during storage, respectively. In the first case, fast migration, which typically last some tens of minutes, was monitored with a temporal resolution 3.5 min or better, while in the second case of slow migration it was monitored during 2 months with 10 days temporal resolution. 3D MR images with sub-millimeter resolution visualise the spatial redistribution of moisture and allow a quantification of its rate and extent of matrix swelling. Correlation with high resolution X-ray (XRT) images allows to identify structural elements responsible for unwanted fast hydration.     

Quantitative investigation of particle formation of a model pharmaceutical formulation using single droplet evaporation experiments and X-ray tomography

The implementation of a particle design platform that can be applied to novel pharmaceutical systems using acoustic levitation (SAL) and X-ray tomography (XRT) is discussed. Acoustic levitation was employed to provide a container-less particle design environment for single droplet evaporation experiments. Dried particles were subject to further visual and quantitative structural analysis using X-ray tomography to assess the three-dimensional volume space. The workflow of the combined SAL-XRT platform has been applied to investigate the impact of increasing HPMC K100LV concentrations on the evaporation, drying and final particle morphology of particles from a model pharmaceutical formulation containing metformin and D-mannitol. The morphology and internal structure of the formulated particles after drying are dominated by a crystalline core of D-mannitol partially suppressed with increasing HPMC K100LV additions. The final structure can be correlated to the observed evaporation kinetics. The characterisation of formulated metformin hydrochloride particles with increasing polymer content demonstrated the importance of an early-stage quantitative assessment of formulation-related particle properties. The ability to study the evolution of solid phase formation and its influence on the final particle morphology can enable the selection of formulation and process parameter that deliver the desired particle structure and consequent performance by design.     

Al基金属玻璃涂层孔隙特性的精确表征及对其腐蚀行为的影响规律

选用Al86Ni6Y4.5Co2La1.5铝基非晶粉体材料,采用自研的低温超音速喷涂系统,在ZM5表面制备了具备良好耐蚀性能的铝基金属玻璃涂层,分析了涂层的孔隙类型及成因,优选出X射线三维成像法测定了涂层孔隙率,表征了涂层孔隙几何特征,阐明了孔隙对涂层腐蚀行为的影响规律。结果表明,涂层主要包含宏观型、层间型、微球型和微细型四类常规孔隙缺陷;涂层孔隙率基本小于1%且沿厚度方向上变化不大,孔隙呈近球形,尺寸均小于10μm,尤以5μm左右居多;不同孔隙率的涂层均呈现出较宽的自钝化区间,自腐蚀电位较为接近,腐蚀电流密度与孔隙率正相关,大尺寸、贯穿型、边界处的个别特殊孔隙是导致涂层腐蚀失效的根本原因。     

A Laser Synthesis Route to Boron-Doped Gold Nanoparticles Designed for X-Ray Radiotherapy and Boron Neutron Capture Therapy Assisted by CT Imaging

New multifunctional theranostic vectors allow the expansion of cancer therapeutic approaches toward scarcely investigated fields. One example is the combination of boron neutron capture therapy (BNCT) and X-ray radiotherapy (XRT) for treating normal and XRT-resistant hypoxic tumor regions and reduce recurrence. Of great relevance for BNCT is also the support of viable, rapid, safe, and reliable techniques for the localization and quantification of the radiosensitizers in the tissues. To address these challenges, polymer-coated Au-B nanoparticles (NPs) are obtained starting from a laser ablation in liquid process. Despite thermodynamic constraints, the two elements coexist by short-range boron segregation in the gold lattice, as demonstrated experimentally and explained with the support of density functional theory calculations. Thus, the Au-B NPs maintain a marked gold character such as biocompatibility, stability, and straightforward surface chemistry with thiolated compounds, desirable for the integration with agents capable of cell targeting and internalization. Overall, the Au-B NPs exhibit the appropriate features for the investigation of combined BNCT and XRT, supported by the localization and quantification with X-ray computed tomography imaging. Besides, the Au-B nanotechnology tool is achievable without renouncing to reproducibility, environmental sustainability, and cost affordability thanks to the laser-assisted synthetic pathway.