Investigating the Performance of the Multi-Lobed Leaf-Shaped Oscillatory Obstacles in Micromixers Using Bulk Acoustic Waves (BAW): Mixing and Chemical Reaction.

Proper mixing in microfluidic devices has been a concern since the early development stages. Acoustic micromixers (active micromixers) attract significant attention due to their high efficiency and ease of implementation. Finding the optimal geometries, structures, and characteristics of acoustic micromixers is still a challenging issue. In this study, we considered leaf-shaped obstacle(s) having a multi-lobed structure as the oscillatory part(s) of acoustic micromixers in a Y-junction microchannel. Four different types of leaf-shaped oscillatory obstacles, including 1, 2, 3, and 4-lobed structures, were defined, and their mixing performance for two fluid streams was evaluated numerically. The geometrical parameters of the leaf-shaped obstacle(s), including the number of lobes, lobes' length, lobes' inside angle, and lobes' pitch angle, were analyzed, and their optimum operational values were discovered. Additionally, the effects of the placement of oscillatory obstacles in three configurations, i.e., at the junction center, on the side walls, and both, on the mixing performance were evaluated. It was found that by increasing the number and length of lobes, the mixing efficiency improved. Furthermore, the effect of the operational parameters, such as inlet velocity, frequency, and intensity of acoustic waves, was examined on mixing efficiency. Meanwhile, the occurrence of a bimolecular reaction in the microchannel was analyzed at different reaction rates. It was proven that the reaction rate has a prominent effect at higher inlet velocities.

The effect of melatonin on testis histological changes and spermatogenesis indexes in mice following treatment with dexamethasone.

Dexamethasone is a common medicine that is capable of causing malformation in the male reproductive system. The aim of this study was to investigate the effect of melatonin on testis histological changes and Spermatogenesis indexes in adult mice following treatment with dexamethasone. Adult male NMRI mice were divided randomly into four groups: control, dexamethasone (i.p injections, 7 mg/kg/day), dexamethasone + melatonin and melatonin (i.p injections, 20 mg/kg/day). After 7 days of treatment, the right testes were studied stereologically and the left testes were used to measure the daily sperm production (DSP). The serum levels of malondialdehyde (MDA), testosterone and total antioxidant capacity (TAC) were also measured. The left caudal epididymis was used to analyze sperm parameters. Data were analyzed using one way ANOVA and means were considered significantly different at p < 0.05. A significant decrease in the testis volume, seminiferous tubules volume, the number of spermatocytes, round and long spermatids, Spermatogenesis indexes, sperm parameters such as motility, count, viability, tail length and DSP, serum testosterone level, TAC and the body weight was found in the dexamethasone group compared to the control. Meanwhile a significant swelling of the interstitial tissue and a significant increase in the MDA level was found in the dexamethasone group compared to the control. The above parameters reached the control level in the dexamethasone + melatonin group. Melatonin can compensate for the adverse effects of dexamethasone on sperm parameters and the histology of the seminiferous tubules in mice.

A novel iron quantum cluster confined in hemoglobin as fluorescent sensor for rapid detection of Escherichia coli.

A new method based on fluorescent probe of iron quantum cluster has been proposed for rapid detection of Escherichia coli (E. coli). The iron quantum cluster was synthesized using hemoglobin as both a source of iron and a protective agent (Hb-FeQCs). The investigation of the sensitivity of Hb-FeQCs towards metal ions showed a highly selective turn off fluorescence for Cu2+. It suggests that Cu2+ can induce fluorescence quenching by binding to amino acids of Hb. The ability of E. coli bacteria to capture and reduce of Cu ions caused to efficient recovery of the fluorescence of Hb-FeQCs from Cu2+-caused quenching. This probe has a satisfactorily linear range of 0.35-35 µM for Cu2+ under the optimal iron quantum cluster concentration (500 µg/mL) with an 85 nM detection limit. Rapid and facile detection of E.coli bacteria with the limit of detection around 8.3 × 103 CFU/mL was successfully achieved in the artificially contaminated urine, tap water, and DMEM samples within 30 min. The fluorescence recovery was investigated by different types of bacteria and only E. coli revealed 56% recovery which related to its capability to Cu2+ reduction and the great potential of the fluorescent probe for rapid detection of pathogenic E. coli bacteria. Furthermore, the Hb-FeQCs can detect E. coli bacteria in an infected urine sample by retrieving up to 74% of its fluorescence which is helpful to accelerate the diagnosis and treatment of urinary tract infection (UTI).

Bone morphogenetic protein-7 incorporated polycaprolactone scaffold has a great potential to improve survival and proliferation rate of the human embryonic kidney cells.

Renal failures treatment has been faced with several problems during the last decades. Kidney tissue engineering has been created many hopes to improve treatment procedures with scaffold fabrication that can modulate kidney cells/stem cells migration to the lesion site and increase the survival of these cells at that site with imitating the role of the kidney extracellular matrix. In this study, bone morphogenetic protein-7 (BMP7) as a vital factor for kidney development and regeneration was incorporated in the polycaprolactone (PCL) nanofibers and after morphological, mechanical, and biocompatible characterization, proliferation, and survival of the human embryonic kidney cells (HEK) were investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry, and gene expression while cultured on scaffolds. Mechanical properties of the PCL nanofibers modulated after combining with BMP7 and hydration degree, protein adsorption and cell adhesion were enhanced in PCL-BMP7 compared to the pure PCL. Proliferation rate and growth increased significantly in HEK cells cultured on PCL-BMP7 when compared with that of PCL and tissue culture plate, whereas these data were also confirmed via significant decrease in apoptotic genes expression level in HEK cell cultured on PCL-BMP7. According to the results, PCL-BMP7 demonstrated positive effects on the survival and proliferation rate of the kidney cells and showed has also a great potential to use as a bioimplant for kidney tissue engineering applications.