In vitro cytotoxicity assessment is indispensable in developing new biodegradable implant materials. Zn, which demonstrates an ideal corrosion rate between Mg‐ and Fe‐based alloys, has been reported ...to have excellent in vivo biocompatibility. Therefore, modifications aimed at improving Zn's mechanical properties should not degrade its biological response. As sufficient strength, ductility and corrosion behavior required of load‐bearing implants has been obtained in plastically deformed Zn‐3Ag‐0.5Mg, the effect of simultaneous Ag and Mg additions on in vitro cytocompatibility and antibacterial properties was studied, in relation to Zn and Zn‐3Ag. Direct cell culture on samples and indirect extract‐based tests showed almost no significant differences between the tested Zn‐based materials. The diluted extracts of Zn, Zn‐3Ag, and Zn‐3Ag‐0.5Mg showed no cytotoxicity toward MG‐63 cells at a concentration of ≤12.5%. The cytotoxic effect was observed only at high Zn2+ ion concentrations and when in direct contact with metallic samples. The highest LD50 (lethal dose killing 50% of cells) of 13.4 mg/L of Zn2+ ions were determined for the Zn‐3Ag‐0.5Mg. Similar antibacterial activity against Escherichia coli and Staphylococcus aureus was observed for Zn and Zn alloys, so the effect is attributed mainly to the released Zn2+ ions exhibiting bactericidal properties. Most importantly, our experiments indicated the limitations of water‐soluble tetrazolium salt‐based cytotoxicity assays for direct tests on Zn‐based materials. The discrepancies between the WST‐8 assay and SEM observations are attributed to the interference of Zn2+ ions with tetrazolium salt, therefore favoring its transformation into formazan, giving false cell viability quantitative results.
Mesoporous bioactive glass nanoparticles (MBGNs) have gained considerable attention as multifunctional platforms for simultaneously releasing ions and phytotherapeutic compounds. Thus, in the first ...part of this study, MBGNs based on the 53SiO2–4P2O5–20CaO–23Na2O (wt %) (S53P4) composition were synthesized by a microemulsion assisted sol-gel method. More precisely, P2O5 was substituted with B2O3 and Na2O with MgO and/or ZnO. For B containing MBGNs all ions were successfully incorporated into the borosilicate structure without inducing crystallisation. In contrast, for S53P4 a poorly crystalline hydroxyapatite phase was identified. All MBGNs had a typical spherical shape with an internal radial network of mesopores. Additionally, for S53P4 a second fraction of particles with a smaller size and compact core was observed. Secondly, the feasibility of MBGNs as nanocarriers for gallic acid (GA) was evaluated. All drug-loaded samples showed a similar in vitro release profile which can be divided into three main phases: burst release, slow release and sustained release. Among the different compositions, S53P4 exhibited the highest cumulative release, whereas B and Mg containing particles exhibited the opposite. The presence of Zn in the MBGN compositions improved their antibacterial effect against both E. coli and S. aureus. Moreover, it was shown that depending on the MBGNs’ composition, the antibacterial activity of GA loaded MBGNs can be enhanced. Thus, the results proved that MBGNs can be used as controlled drug delivery system and, by tailoring the composition, a synergistic antibacterial effect can be achieved, considering that GA and biologically active ions are simultaneously released.
Display omitted
Bioactive glasses have been proposed for bone tissue engineering due to their excellent biocompatibility and osteo-inductive behaviour. The generation of mesoporous bioactive glass (nano) particles ...adds a high surface area for the dissolution and release of bioactive ions, and the possibility to load them with different drugs for antibacterial purposes. Essential oils (EO) are an interesting resource for alternative medical therapy, providing antimicrobial compounds that come from organic/natural resources like aromatic plants. Also, a biological polymer, such as chitosan, could be used to control the release of active agents from mesoporous bioactive glass (MBG) loaded particles. This work presents MBG particles with nominal composition (in mol) 60% SiO
, 30% CaO and 10% P
O
, loaded with essential oil of
, which contains 1,8-cineol as the main active component, with an inhibitory in vitro activity against several bacterial species. Also, co-loading with a broad-spectrum antibiotic, namely gentamicin, was investigated. The MBG particles were found to be of around 300nm in diameter and to exhibit highly porous open structure. The release of EO from the particles reached 72% of the initial content after the first 24 h, and 80% at 48 h of immersion in phosphate buffered solution. Also, the MBG particles with EO and EO-gentamicin loading presented in vitro apatite formation after 7 days of immersion in simulated body fluid. The antibacterial tests indicated that the main effect, after 24 h of contact with the bacteria, was reached either for the MBG EO or MBG EO-gentamicin particles against
, while the effect against
was less marked. The results indicate that MBG particles are highly bioactive with the tested composition and loaded with EO of
. The EO, also combined with gentamicin, acts as an antibacterial agent but with different efficacy depending on the bacteria type.
Display omitted
•The highest Pmax was obtained from F2@60ppm at 100% load.•The COVIMEP was improved with nano additive for all loads under dual fuel mode.•BTEs of modified fuels under dual fuel mode ...were higher than F2 for all loads.•The highest energy share was computed as 13.7% for F2 @60ppm at the full load.•The drawback of modified fuels was observed NO emission under dual fuel mode.
Biogas has been investigated as an alternative biofuel in dual fuel operating mode in a direct injection diesel engine. However, there is not sufficient information about using modified fuels with biogas. This study aimed to investigate the effects of modified diesel fuel and biogas on combustion behavior, performance, and emissions characteristics at 1500 rpm constant speed with 5 different load conditions at an interval of 25%. Diesel was modified with multi-walled carbon nanotubes with 30, 60, and 90 ppm. Diesel fuel and three modified fuels were used as pilot fuel and biogas was introduced through the intake manifold with the flow rate of 500 g/h as the primary fuel. Diesel mode fuels were denominated F1 while dual fuel mode fuels were labeled as F2, and the concentration levels were given subscript such as F2 @60ppm. The experimental study revealed that modified fuel showed better combustion behaviors, performance, and emissions in comparison to diesel fuel. Further, the same trend was observed in the dual fuel mode. The maximum pressure of F2 @60 ppm was 1% higher than F2 under dual fuel mode at the full load. Moreover, the coefficient of variation of the indicated mean effective pressure for dual fuel mode was found approximately 9.2, 6.9, 6.2, and 7.2% for F2, F2 @30 ppm, F2 @60 ppm, and F2 @90 ppm, respectively at full load. In addition, the energy share of biogas increased by 7.9, 8.7, and 7.1% for F2 @30 ppm, F2 @60 ppm, and F2 @90 ppm, respectively in comparison with F2 at full load. The highest decrease of brake specific energy consumption under the dual mode was obtained to be an 8% drop from F2 @60 ppm compared to F2 at full load. At the same load, the brake thermal efficiency of F2 @30 ppm, F2 @60 ppm, and F2 @90 ppm were noted to be 30.2, 30.4, and 30.0%, respectively which are higher than F2 (27.9%). The value of replaced diesel with biogas was noted 0.09, 0.23, 0.24, and 0.22 kg/h for F2, F2 @30 ppm, F2 @60 ppm, and F2 @90 ppm, respectively under the full load condition. Lastly, CO and HC emissions were almost the same value with and without modified fuel for dual fuel mode at the full load. Nevertheless, NO emission was slightly increased with modified fuel compared to F2. From these findings, it can be suggested that 60 ppm multi-walled carbon nanotubes additive can be an optimum level for combustion, performance, and emissions under the dual fuel mode.
In the present study, our main aim is to show that the first synthesized metal-doped tea factory waste (TFW) catalyst can be used in both hydrogen production and supercapacitor application. In this ...context, TFW catalyst doped with copper (Cu) (TFW-Cu) was synthesized for methanolysis of NaBH
4
and supercapacitor measurement. In the presence of four different parameters (metal type, metal amount, carbonization temperature, and carbonization time), methanolysis experiments of NaBH
4
were performed and the catalyst with the maximum hydrogen production rate (HPR) was determined. As a result, it was determined that the 30% Cu-doped TFW (TFW-30%Cu) catalyst had a maximum HPR at a carbonization temperature of 300 °C and a carbonization time of 60 min compared to other substances. As a result of the methanolysis experiments performed in the presence of TFW-30%Cu catalyst, the maximum HPR and activation energy were determined as 9475 mL (min.g)
−1
and 13.02 kJ mol
−1
, respectively. In supercapacitor application, the capacitance of the electrodes in the presence of TFW-30%Cu was calculated as 7–19.9 F.(g)
−1
. Thus, it is expected that the synthesized catalyst will make a promising contribution in both energy storage and energy production areas—especially for distributed generation systems operating in national networks.
Reflection and transmission through a solar cell can be significantly reduced using light-trapping structures. This approach can be applied to both crystalline and thin-film solar cells to improve ...the light absorption and conversion efficiency of the cell. In this study, vertically aligned Si nanowires were fabricated over a large area via a metal-assisted etching technique. Following a detailed parametric study, nanowires were applied to industrial-size (156 mm × 156 mm) Si solar cells. The reflectivity from the device surface was reduced to less than 5% for the entire visible spectrum (350-750 nm), including the blue-violet region. Standard solar cell fabrication procedures were employed to fabricate cells with and without Si nanowires, and the results showed that the efficiencies of solar cells with nanowires were similar to those of standard pyramid-textured cells, revealing the potential of the proposed concept. A systematic study of the dependence of the solar cell parameters on the length of the nanowires was performed. The quantum efficiency of the cells exhibited relatively poor performance in the blue-ultraviolet range of the spectrum, and enhancement in carrier generation was observed in the red-infrared region especially for shorter nanowires.
Bioactive glasses have been proposed for bone tissue engineering due to their excellent biocompatibility and osteo-inductive behaviour. The generation of mesoporous bioactive glass (nano) particles ...adds a high surface area for the dissolution and release of bioactive ions, and the possibility to load them with different drugs for antibacterial purposes. Essential oils (EO) are an interesting resource for alternative medical therapy, providing antimicrobial compounds that come from organic/natural resources like aromatic plants. Also, a biological polymer, such as chitosan, could be used to control the release of active agents from mesoporous bioactive glass (MBG) loaded particles. This work presents MBG particles with nominal composition (in mol) 60% SiOsub.2 , 30% CaO and 10% Psub.2 Osub.5 , loaded with essential oil of Melaleuca armillaris, which contains 1,8-cineol as the main active component, with an inhibitory in vitro activity against several bacterial species. Also, co-loading with a broad-spectrum antibiotic, namely gentamicin, was investigated. The MBG particles were found to be of around 300nm in diameter and to exhibit highly porous open structure. The release of EO from the particles reached 72% of the initial content after the first 24 h, and 80% at 48 h of immersion in phosphate buffered solution. Also, the MBG particles with EO and EO-gentamicin loading presented in vitro apatite formation after 7 days of immersion in simulated body fluid. The antibacterial tests indicated that the main effect, after 24 h of contact with the bacteria, was reached either for the MBG EO or MBG EO-gentamicin particles against E. coli, while the effect against S. aureus was less marked. The results indicate that MBG particles are highly bioactive with the tested composition and loaded with EO of Melaleuca armillaris. The EO, also combined with gentamicin, acts as an antibacterial agent but with different efficacy depending on the bacteria type.
This paper analyses the adoption of the EU Strategic Environmental Assessment Directive (2001/42/EC) in Turkey as part of a programme of environmental policy harmonisation for EU accession, to ...explore the extent to which this is driving wider shifts in modes of environmental governance. To do this, rather than simply assess compliance with Directive in narrow, formal, statutory terms, we use Jänicke and Weidner's concept of capacity building, which focuses on the constraints facing societal action to promote sustainable development. Despite the resources invested in pre-accession training and pilot SEA projects, Turkey's adoption of the Directive is still likely to be affected by the centralised nature of the bureaucracy (affecting the scope for sectoral integration), its politicised nature (interrupting the accumulation of policy learning), the limited capacity of civil society and environmental organisations to engage with the process, and the political dominance of economic development objectives.
