Dip coating of forsterite-hydroxyapatitie-poly (ɛ-caprolactone) nanocomposites on Ti6Al4Vsubstrates for its corrosion prevention

522-528Titanium and titanium alloys are extensively used in biomedical, cardiac and cardiovascular applications for their superb properties, such as good fatigue strength, low modulus, machinability, formability, corrosion resistance and biocompatibility. However, titanium and its alloys do not meet the majority of all clinical necessities. Due to these reasons, surface modification is frequently performed to enhance the mechanical, biological and chemical properties of titanium and alloys. In this work, nanocomposites coating of poly(ɛ-caprolactone)/hydroxyapatite/forsterite (PCL/HA/F) have been successfully deposited on the Ti6Al4V substratesby dip coating at room temperature. The coatings are prepared with various concentrations of forsterite/hydroxyapatite nanopowder (2, 4, 6 and 8 wt.%) with a fixed concentration of PCL (4 wt.%) and thus coated Ti6Al4V substrates are examined for corrosion resistance. PCL/Hydroxyapatite/Forsterite coatings are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which clearly showed the formation of nanocomposites. Potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) are used to investigate corrosion behavior of the coated substrates, which portrayed that the composite coating of PCL/HA/F substantially enhanced the corrosion resistance of Ti6Al4V alloy

Dip coating of forsterite-hydroxyapatitie-poly (ɛ-caprolactone) nanocomposites on Ti6Al4Vsubstrates for its corrosion prevention

Titanium and titanium alloys are extensively used in biomedical, cardiac and cardiovascular applications for their superb properties, such as good fatigue strength, low modulus, machinability, formability, corrosion resistance and biocompatibility. However, titanium and its alloys do not meet the majority of all clinical necessities. Due to these reasons, surface modification is frequently performed to enhance the mechanical, biological and chemical properties of titanium and alloys. In this work, nanocomposites coating of poly(ɛ-caprolactone)/hydroxyapatite/forsterite (PCL/HA/F) have been successfully deposited on the Ti6Al4V substratesby dip coating at room temperature. The coatings are prepared with various concentrations of forsterite/hydroxyapatite nanopowder (2, 4, 6 and 8 wt.%) with a fixed concentration of PCL (4 wt.%) and thus coated Ti6Al4V substrates are examined for corrosion resistance. PCL/Hydroxyapatite/Forsterite coatings are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which clearly showed the formation of nanocomposites. Potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) are used to investigate corrosion behavior of the coated substrates, which portrayed that the composite coating of PCL/HA/F substantially enhanced the corrosion resistance of Ti6Al4V alloy

Pressurized metered-dose inhalers using next-generation propellant HFO-1234ze(E) deposit negligible amounts of trifluoracetic acid in the environment

Pressurized metered-dose inhalers (pMDIs) deliver life-saving medications to patients with respiratory conditions and are the most used inhaler delivery device globally. pMDIs utilize a hydrofluoroalkane (HFA), also known as an F-gas, as a propellant to facilitate the delivery of medication into the lungs. Although HFAs have minimal impact on ozone depletion, their global warming potential (GWP) is more than 1,000 times higher than CO2, bringing them in scope of the F-Gas Regulation in the European Union (EU). The pharmaceutical industry is developing solutions, including a near-zero GWP “next-generation propellant,” HFO-1234ze(E). At the same time, the EU is also evaluating a restriction on per-and polyfluoroalkyl substances (PFAS) under the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) regulation. Trifluoroacetic acid (TFA) is a persistent PFAS and a potential degradation product of HFO-1234ze(E). We quantified yield of TFA from HFO-1234ze(E) using a computational model under Europe-relevant atmospheric conditions. The modeling suggests that most HFO-1234ze(E) degrades into formyl fluoride within 20 days (≥85%) even at the highest examined altitude. These results suggest that TFA yield from HFO-1234ze(E) varies between 0%–4% under different atmospheric conditions. In 2022, France represented the highest numbers of pMDI units sold within the EU, assuming these pMDIs had HFO-1234ze(E) as propellant, we estimate an annual rainwater TFA deposition of ∼0.025 μg/L. These results demonstrate negligible formation of TFA as a degradation product of HFO-1234ze(E), further supporting its suitability as a non-persistent, non-bioaccumulative, and non-toxic future propellant for pMDI devices to safeguard access for patients to these essential medicines

A Mathematical model for Astrocytes mediated LTP at Single Hippocampal Synapses

Many contemporary studies have shown that astrocytes play a significant role in modulating both short and long form of synaptic plasticity. There are very few experimental models which elucidate the role of astrocyte over Long-term Potentiation (LTP). Recently, Perea & Araque (2007) demonstrated a role of astrocytes in induction of LTP at single hippocampal synapses. They suggested a purely pre-synaptic basis for induction of this N-methyl-D- Aspartate (NMDA) Receptor-independent LTP. Also, the mechanisms underlying this pre-synaptic induction were not investigated. Here, in this article, we propose a mathematical model for astrocyte modulated LTP which successfully emulates the experimental findings of Perea & Araque (2007). Our study suggests the role of retrograde messengers, possibly Nitric Oxide (NO), for this pre-synaptically modulated LTP.Comment: 51 pages, 15 figures, Journal of Computational Neuroscience (to appear