Effect of Inducers, Incubation Time and Heme Concentration on IC(50) Value Variation in Anti-heme Crystallization Assay

Numerical and Experimental Study of Cross-Sectional Effects on the Mixing Performance of the Spiral Microfluidics

Mixing at the microscale is of great importance for various applications ranging from biological and chemical synthesis to drug delivery. Among the numerous types of micromixers that have been developed, planar passive spiral micromixers have gained considerable interest due to their ease of fabrication and integration into complex miniaturized systems. However, less attention has been paid to non-planar spiral micromixers with various cross-sections and the effects of these cross-sections on the total performance of the micromixer. Here, mixing performance in a spiral micromixer with different channel cross-sections is evaluated experimentally and numerically in the Re range of 0.001 to 50. The accuracy of the 3D-finite element model was first verified at different flow rates by tracking the mixing index across the loops, which were directly proportional to the spiral radius and were hence also proportional to the Dean flow. It is shown that higher flow rates induce stronger vortices compared to lower flow rates; thus, fewer loops are required for efficient mixing. The numerical study revealed that a large-angle outward trapezoidal cross-section provides the highest mixing performance, reaching efficiencies of up to 95%. Moreover, the velocity/vorticity along the channel length was analyzed and discussed to evaluate channel mixing performance. A relatively low pressure drop (<130 kPa) makes these passive spiral micromixers ideal candidates for various lab-on-chip applications.

Potent α-amylase inhibitory activity of sprouted quinoa-based yoghurt beverages fermented with selected anti-diabetic strains of lactic acid bacteria

The in vitro inhibitory effect of sprouted quinoa yoghurt beverages (QYB) fermented with anti-diabetic lactic acid bacteria on α-amylase was investigated. In vitro studies using porcine pancreatic α-amylase showed that quinoa yoghurt beverages fermented with Lactobacillus casei Zhang and Lactobacillus casei SY13 dose-dependently inhibited the activities of α-amylase. The saponin content, reducing and total sugars were also quantified to determine their potency as anti-hyperglycemic agents against type 2 diabetes mellitus. The saponin contents of the yoghurt beverages were relatively low at a range of 0.19-0.41%, and significantly reduced as germination time increased. Germination significantly decreased the reducing sugars in all samples. A total of 4 sugars were identified using HPLC. Quinoa yoghurt beverages can be targeted as a potential dual-inhibitory strategy to attenuate type 2 diabetes mellitus by their ability to inhibit α-amylase activity as well as reduce or prevent hyperglycemic conditions associated with elevated levels of sugar glucose in the blood.

Quinoline drug-heme interactions and implications for antimalarial cytostatic versus cytocidal activities

Historically, the most successful molecular target for antimalarial drugs has been heme biomineralization within the malarial parasite digestive vacuole. Heme released from catabolized host red blood cell hemoglobin is toxic, so malarial parasites crystallize heme to nontoxic hemozoin. For years it has been accepted that a number of effective quinoline antimalarial drugs (e.g., chloroquine, quinine, amodiaquine) function by preventing hemozoin crystallization. However, recent studies over the past decade have revealed a surprising molecular diversity in quinoline-heme molecular interactions. This diversity shows that even closely related quinoline drugs may have quite different molecular pharmacology. This paper reviews the molecular diversity and highlights important implications for understanding quinoline antimalarial drug resistance and for future drug design.