An examination of the thermorheological and drug release properties of zinc tetraphenylporphyrin-containing thermoresponsive hydrogels, designed as light activated antimicrobial implants

This study describes the thermorheological, mechanical and drug release properties of novel, light-activated antimicrobial implants. Hydrogels, based on N-isopropylacrylamide (NIPAA) and hydroxyethyl methacryl ate (HEMA) and either devoid of or containing zinc tetraphenylporphyrin, were prepared by free radical polymerisation and characterised using oscillatory rheometry and texture profile analysis. Drug release was studied at both 20 and 37 degrees C. Hydrogels containing NIPAA exhibited a sol-gel temperature (Tin), which increased as the proportion of HEMA increased and was

Effect of a biofilm on the adsorption of 4-chlorophenol on activated carbon

The adsorption of 4-chlorophenol (4-CP) on activated carbon was studied experimentally both in the presence and in the absence of an inactivated anaerobic biofilm on the surface of carbon pellets. The presence of the biofilm markedly decreased the rate of 4-CP adsorption. However, the final near-equilibrium state (at 27 h) was not affected, and the incremental amount of material adsorbed on the pellets was similar both in the presence and in the absence of the biofilm. The biosorption of 4-CP by a biofilm coating non-adsorbing pellets was also determined. It appears that the biofilm also has some adsorption capability. Freundlich-type equations were used to correlate all data, and transient and near-equilibrium isotherms were obtained for 4-CP adsorption on different adsorbing materials at different times.

Chemical and mechanical stability of sodium sulfate activated slag after exposure to elevated temperature

The chemical and mechanical stability of slag activated with two different concentrations of sodium sulfate (Na₂SO₄) after exposure to elevated temperatures ranging from 200 to 800 °C with an increment of 200 °C has been examined. Compressive strengths and pH of the hardened pastes before and after the exposure were determined. The various decomposition phases formed were identified using X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. The results indicated that Na₂SO₄ activated slag has a better resistance to the degradation caused by exposure to elevated temperature up to 600 °C than Portland cement system as its relative strengths are superior. The finer slag and higher Na₂SO₄ concentration gave better temperature resistance. Whilst the pH of the hardened pastes decreased with an increase in temperature, it still maintained a sufficiently high pH for the protection of reinforcing bar against corrosion.

Autophagy stimulation by rapamycin suppresses lung inflammation and infection by Burkholderia cenocepacia in a model of cystic fibrosis

Cystic fibrosis (CF) is the most common inherited lethal disease in Caucasians which results in multiorgan dysfunction. However, 85% of the deaths are due to pulmonary infections. Infection by Burkholderia cenocepacia (B. cepacia) is a particularly lethal threat to CF patients because it causes severe and persistent lung inflammation and is resistant to nearly all available antibiotics. In CFTR Delta F508 (Delta F508) mouse macrophages, B. cepacia persists in vacuoles that do not fuse with the lysosomes and mediates increased production of IL-1 beta. It is believed that intracellular bacterial survival contributes to the persistence of the bacterium. Here we show for the first time that in wild-type but not in Delta F508 macrophages, many B. cepacia reside in autophagosomes that fuse with lysosomes at later stages of infection. Accordingly, association and intracellular survival of B. cepacia are higher in CFTR-Delta F508 macrophages than in WT macrophages. An autophagosome is a compartment that engulfs nonfunctional organelles and parts of the cytoplasm then delivers them to the lysosome for degradation to produce nutrients during periods of starvation or stress. Furthermore, we show that B. cepacia downregulates autophagy genes in WT and Delta F508 macrophages. However, autophagy dysfunction is more pronounced in Delta F508 macrophages since they already have compromised autophagy activity. We demonstrate that the autophagy-stimulating agent, rapamycin markedly decreases B. cepacia infection in vitro by enhancing the clearance of B. cepacia via induced autophagy. In vivo, rapamycin decreases bacterial burden in the lungs of CF mice and drastically reduces signs of lung inflammation. Together, our studies reveal that if efficiently activated, autophagy can control B. cepacia infection and ameliorate the associated inflammation. Therefore, autophagy is a novel target for new drug development for CF patients to control B. cepacia infection and accompanying inflammation.