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Improvement of properties of self-flowing low-cement castables based on brownfused alumina
Necip Ünlü,Cem Gögtas,Akln Odabasl,Levent Sezer,Filiz Çlnar,Sule Güner,Niyazi Eruslu 한양대학교 세라믹연구소 2007 Journal of Ceramic Processing Research Vol.8 No.5
A new self flowing brown-fused alumina based castable with 5 wt.% cement has been developed. An Andreason mathematical model (q=0.25) was used to adjust the granulometric particle size distribution. To achieve optimum self-leveling flowability, 5.6% water was used. The main physical and mechanical properties of the present castable were studied. Phase analysis using X-ray diffraction (XRD), scanning electron microscopy (SEM) and apparent porosity (AP), bulk density (BD), water absorption (WA), cold crushing strength (CCS), hardness, and self-leveling flowability were investigated as a function of the firing temperature. The castable exhibited low AP and WA, and high CCS values with an increase in the firing temperature as a result of the corresponding phases. A new self flowing brown-fused alumina based castable with 5 wt.% cement has been developed. An Andreason mathematical model (q=0.25) was used to adjust the granulometric particle size distribution. To achieve optimum self-leveling flowability, 5.6% water was used. The main physical and mechanical properties of the present castable were studied. Phase analysis using X-ray diffraction (XRD), scanning electron microscopy (SEM) and apparent porosity (AP), bulk density (BD), water absorption (WA), cold crushing strength (CCS), hardness, and self-leveling flowability were investigated as a function of the firing temperature. The castable exhibited low AP and WA, and high CCS values with an increase in the firing temperature as a result of the corresponding phases.
Electrospun Nanofibers for Dual and Local Delivery of Neuroprotective Drugs
Mohammad Karim Haidar,Selin Seda Timur,Gülen Melike Demirbolat,Emirhan Nemutlu,R. Neslihan Gürsoy,Kezban Ulubayram,Levent Öner,Hakan Eroğlu 한국섬유공학회 2021 Fibers and polymers Vol.22 No.2
Drug delivery for neuroprotection/neuroregeneration after traumatic peripheral nerve injuries still remains achallenge. For this purpose, we formulated composite nanofiber formulation for the dual local delivery of alpha lipoic acid(ALA) and atorvastatin (ATR) to enhance regeneration process after peripheral nerve injury. The initial stage involvedencapsulation of ATR into nanosprayed chitosan (CH) nanoparticles after which the CH nanoparticles were embedded intopoly(lactic-co-glycolic acid) (PLGA) nanofibers containing freely dispersed ALA within the fiber structure. Morphologyinvestigations revealed that smooth and randomly aligned nanofibers with mean diameter of 340±69 nm were formed. Encapsulation efficiency for ALA and ATR were calculated as 92.76±3.53 % and 89.27±5.053 %, respectively. DifferentialScanning Calorimetry and FT-IR analysis confirmed successful encapsulation of ALA and ATR into the compositenanofibers; however, XRD results indicated surface localization of ALA within the structure. Porosity and pore volume of thenanofibers increased in accordance with increase in density of the electrospunned solution. Similarly, mechanical strength ofthe nanofibers was found to increase significantly following the incorporation of ALA and ATR with respect to the unloadednanofibers (p<0.05). Dual release of ALA and ATR in different fashions was confirmed by in-vitro release test of thenanofibers. For ALA, an immediate release percentage of 83.90 % within the first hour was observed. On the other hand,ATR exhibited a three-stage release profile which begins with a relatively lower initial release (22.07 %) in comparison toALA followed by an increasing release (82.439 %) up to 150 h. According to cell viability results, blank and loadedformulations were found to have no cytotoxic effect on both L-929 and B35 cell lines after incubation for up to 48 h. Basedon this, composite PLGA nanofibers could be classified as suitable candidates for long-term and local delivery ofneuroprotective drugs in peripheral nerve injury.