Understanding the Effect of Reflow Profile on the Metallurgical Properties of Tin–Bismuth Solders

Sn–Bi alloys are desirable candidates for soldering components on printed circuit boards (PCBs) because of their low melting point and reduced cost. While certain tin–bismuth solders are well characterized many new alloys in this family have been developed which need proper characterization. The following study looks at the behavior of four different Sn–Bi alloys—traditional 42Sn58Bi and 42Sn57Bi1Ag and two new tin–bismuth alloys—in solder paste during the reflow soldering process. Each alloy was processed using different reflow profiles that had varying times above liquidus (TALs) and peak temperatures. The PCBs were then analyzed to see how the processing variables influenced wetting, voiding, microstructure, intermetallic layer composition, and thickness. After analysis, the PCBs were then subjected to thermal cycling experiments to see how reflow profile impacted microstructure evolution. The results demonstrated that reflow profile affects properties such as metal wetting and voiding. It does not however, greatly impact key metallurgical properties such as intermetallic layer thickness.

Preparation of Nanoemulsion

Nanoemulsion is a versatile emulsion-based delivery system that can be structured or prepared with different compositions, methods, or processing variables. Although single nanoemulsion has been a promising delivery carrier in numerous industries, the innovation of double nanoemulsion is introduced to provide different benefits. However, the nanoemulsion must be optimized in terms of the composition and emulsification methods to maintain the integrity of the delivery system. Therefore, the optimization of nanoemulsion can range from deciding the type and concentration of compositions (aqueous, lipid, surfactants) to the processing conditions during emulsification. The current options of emulsification methods, processing parameters, and optimization process of nanoemulsion are highlighted and elaborated in this chapter. This allows readers to understand the fundamental principles of nanoemulsion preparation and encourage future studies and applications in the related field.

Process-Induced Modifications on Quality Attributes of Cassava (Manihot esculenta Crantz) Flour

Cassava flour (CF) is a suitable representative and one of the easiest shelf-stable food products of the edible portion of the highly perishable cassava root (Manihot esculenta Crantz). The quality and type of CF are dependent on processing variables. Broadly categorized into fermented and unfermented CF, unfermented CF is white, odorless, and bland, while fermented CF has a sour flavor accompanied by its characteristic odor. The use of fermented CF as a composite is limited because of their off-odors. Modifications in CF processing have given rise to prefixes such as: modified, unmodified, gelatinized, fortified, native, roasted, malted, wet, and dry. Consumed alone, mostly in reconstituted dough form with soups, CF may also serve as a composite in the processing of various flour-based food products. Fermenting with microorganisms such as Rhizopus oryzae and Saccharomyces cerevisiae results in a significant increase in the protein content and a decrease in the cyanide content of CF. However, there are concerns regarding its safety for consumption. Pre-gelatinized CF has potential for the textural and structural improvement of bakery products. The average particle size of the CF also influences its functional properties and, subsequently, the quality of its products. Cassava flour is best stored at ambient temperature. Standardizing the processing of CF is a challenge because it is mostly processed in artisanal units. Furthermore, each variety of the root best suits a particular application. Therefore, understanding the influence of processing variables on the characteristics of CF may improve the utilization of CF locally and globally.

When Origin Matters: Properties of Mesenchymal Stromal Cells From Different Sources for Clinical Translation in Kidney Disease

Advanced therapy medicinal products (ATMPs) offer new prospects to improve the treatment of conditions with unmet medical needs. Kidney diseases are a current major health concern with an increasing global prevalence. Chronic renal failure appears after many years of impairment, which opens a temporary window to apply novel therapeutic approaches to delay or halt disease progression. The immunomodulatory, anti-inflammatory, and pro-regenerative properties of mesenchymal stromal cells (MSCs) have sparked interest for their use in cell-based regenerative therapies. Currently, several early-phase clinical trials have been completed and many are ongoing to explore MSC safety and efficacy in a wide range of nephropathies. However, one of the current roadblocks to the clinical translation of MSC therapies relates to the lack of standardization and harmonization of MSC manufacturing protocols, which currently hinders inter-study comparability. Studies have shown that cell culture processing variables can have significant effects on MSC phenotype and functionality, and these are highly variable across laboratories. In addition, heterogeneity within MSC populations is another obstacle. Furthermore, MSCs may be isolated from several sources which adds another variable to the comparative assessment of outcomes. There is now a growing body of literature highlighting unique and distinctive properties of MSCs according to the tissue origin, and that characteristics such as donor, age, sex and underlying medical conditions may alter the therapeutic effect of MSCs. These variables must be taken into consideration when developing a cell therapy product. Having an optimal scale-up strategy for MSC manufacturing is critical for ensuring product quality while minimizing costs and time of production, as well as avoiding potential risks. Ideally, optimal scale-up strategies must be carefully considered and identified during the early stages of development, as making changes later in the bioprocess workflow will require re-optimization and validation, which may have a significant long-term impact on the cost of the therapy. This article provides a summary of important cell culture processing variables to consider in the scale-up of MSC manufacturing as well as giving a comprehensive review of tissue of origin-specific biological characteristics of MSCs and their use in current clinical trials in a range of renal pathologies.

Biocompatible Sulphonated PEEK Spheres: Influence of Processing Conditions on Morphology and Swelling Behavior

This work aimed to develop and evaluate the influence of processing variables on the morphology and swelling of sulfonated poly(ether ether ketone) (SPEEK) spheres for possible applications as a biomaterial. We used the drip method to obtain spheres with the polymer starting solutions SPEEK-6 (w/v: 6%) and SPEEK-10 (w/v: 10%), drip rates (20 and 30 mL/h), and drip heights (5 and 10 cm) in experimental planning. The samples were characterized by Fourier-transform infrared spectroscopy (FTIR), optical microscopy (OM), the absorption capacity of phosphate-buffered saline (PBS) by swelling (%), and statistical analysis of data through Design of Experiments (DOE). The obtained results evidenced that the processing variables influenced the morphology and swelling. Spheres with a bigger concentration of the polymer solution presented a greater degree of sulfonation (DS). We verified that the diameter of the spheres was directly related to the variable height and the sphericity was associated with the speed and viscosity of the solution. Bigger and more pores in a greater amount were observed in the spheres with a greater DS, influencing the behavior of the swelling in PBS. The better variable combinations with a high DS, regular sphericity, a smaller diameter, and greater swelling were the samples S2-10-20-5 e S10-10-20-5. The cytotoxicity indicated that the best samples obtained in the experimental planning (S2-10-20-5 and S10-10-20-5) were not toxic. In that regard, the evaluated spheres presented cell viability and swelling capacity, suggesting their possible applications as biomaterials.