Microfluidic device for synthesis of chitosan nanoparticles

Chitosan nanoparticles have a biodegradable, biocompatible, non-toxic structure, and commonly used for drug delivery systems. In this paper, simulation of a microfluidic device for the synthesis of chitosan nanoparticle is presented. The flow filed together with the concentration field within the microchannel network is simulated using COMSOL Multiphysics® simulation environment. Different microchannel geometries are analyzed, and the mixing performance of these configurations are compared. As a result, a 3D design for a microfluidics platform which includes four channel each of which performs the synthesis in parallel is proposed. Future research directions regarding the fabrication of the microfluidic device and experimentation phase are addressed and discussed. Copyright © 2013 by ASME

Preparation and characterization of polyethyleneglycolmethacrylate (PEGMA)-co-vinylimidazole (VI) microspheres to use in heavy metal removal

Polyethyleneglycolmethacrylate (PEGMA) and vinylimidazole (VI) were used in order to obtain microspheres of PEGMA-VI copolymers that can be used in heavy metal removal applications. The obtained copolymers were characterized and their use as sorbents in heavy metal removal was investigated. In the first part of the study, PEGMA-VI microspheres were prepared by suspension polymerization method. The obtained swellable microspheres with 10-50 μm average diameter did not have permanent porosity according to the morphological and physicochemical determinations. The sizes of microspheres became smaller with increasing VI and cross-linker ethyleneglycoldimethacrylate (EGDMA) contents and increasing agitation rate. The VI content, EGDMA ratio, pH and ionic strength were determined as the effective parameters on the swelling behavior of PEGMA-VI microspheres. In the second part of the study, Cu(II) ions were used as a model species in order to investigate the usability of the obtained PEGMA-VI microspheres in heavy metal removal. Adsorption capacities under optimum conditions were determined. The Cu(II) ion adsorption capacity increased by increasing the initial Cu(II) ion concentration, and it reached the maximum value (i.e., 30 mg Cu(II)/g PEGMA-VI microspheres) at 400 mg Cu(II)/L initial Cu(II) ion concentration under the determined optimum conditions. Microspheres were found to be reusable after desorption for several times. © 2008 Elsevier B.V. All rights reserved

Evaluation of growth in children and adolescents after renal transplantation

Büyükkaragöz B, Bakkaloğlu SA, Tuncel AF, Kadıoğlu-Yılmaz B, Karcaaltıncaba D, Paşaoğlu H. Evaluation of growth in children and adolescents after renal transplantation. Turk J Pediatr 2019; 61: 217-227. Despite the advances in the last decades, it is well-known that optimal growth is usually not achieved in children with chronic kidney disease (CKD) even after successful renal transplantation (RTx). In this study, our aim was to evaluate growth patterns and factors affecting growth in pediatric and adolescent renal transplant recipients (RTR). Thirty-seven prevalent RTR with mean age of 17.0±2.9 years and mean post-RTx duration of 4.2±2.0 years were evaluated. Growth parameters, height velocities and factors affecting growth at the time of RTx (baseline) and in the post-RTx follow-up were also retrospectively assessed. Cumulative corticosteroid (CS) doses were calculated. Mean height and weight standard deviation score (SDS) values were negative (-1.4±1.1 and -1.2±1.5, respectively), whereas height SDS was positive in 16% of the patients. Mean weight, height, and BMI (body mass index) SDS of the RTR were significantly higher than the values at transplantation (p < 0.001 for weight and height SDS; p < 0.05 for BMI SDS). Height SDS was < -2.0 in 19% of the patients while 60% at the baseline. Main factors associated with post-RTx height SDS were pre-RTx height SDS (B: 0.448, p < 0.01) and CKD duration (B: -0.01, p < 0.05). Although it was much better than the pre-RTx period, the present study reveals that post- RTx growth was less than anticipated. As well as minimizing post-RTx CS doses and preserving graft function in the post-RTx follow-up, performing early transplantation and all efforts for minimizing pre-RTx growth deficit are crucial for an optimal post-RTx growth