Preparation and characterization of polyethylene-based hybrid particles by an environmentally-friendly and aqueous solvent evaporation method

The present paper reports preparation procedure and characterization of micrometer-sized polyethylene (PE)-based hybrid particles containing various amounts of Mg(OH)2 powder treated with different amounts of methylhydrogen polysiloxane (MHS). The PE-based hybrid particles were fabricated by an environmentally-friendly and aqueous solvent evaporation method by employing different kinds of surfactants. The shape, microstructure and other properties of the resultant PE-based hybrid particles were dependent markedly on the changes in composition of raw materials, especially for the amount of MHS used for the treatment of Mg(OH)2 and the kind of surfactant. The particles fabricated by using 1 wt% MHS-treated Mg(OH)2 (ST-1) powder and polyoxyethylene (10) octylphenyl ether (Triton X-100) as a surfactant showed spherical shape and their primary particle sizes were about 4--10 μm, irrespective of the additive amount of ST-1 powder. These particles showed superior properties in terms of the actual content of MHS-treated Mg(OH)2 powder incorporated inside the hybrid particles, particle size distribution and particle shape, in comparison with other particles fabricated by using 5 wt% MHS-treated Mg(OH)2 (ST-5) powder and polyoxyethylene (8) octylphenyl ether (Triton X-114) as a surfactant. This is due to good affinity (average contact angle was 19.4°) between the ST-1 powder and the aqueous phase, i.e. a continuous phase, dissolving Triton X-100. Furthermore, a composite fabricated by employing these PE-based hybrid particles showed uniform and homogeneous distribution of ST-1 powder in the PE matrix

Preparation of polycaprolactone nanoparticles via supercritical carbon dioxide extraction of emulsions

Polycaprolactone (PCL) nanoparticles were produced via supercritical fluid extraction of emulsions (SFEE) using supercritical carbon dioxide (scCO2). The efficiency of the scCO2 extraction was investigated and compared to that of solvent extraction at atmospheric pressure. The effects of process parameters including polymer concentration (0.6–10% w/w in acetone), surfactant concentration (0.07 and 0.14% w/w) and polymer-to-surfactant weight ratio (1:1–16:1 w/w) on the particle size and surface morphology were also investigated. Spherical PCL nanoparticles with mean particle sizes between 190 and 350 nm were obtained depending on the polymer concentration, which was the most important factor where increase in the particle size was directly related to total polymer content in the formulation. Nanoparticles produced were analysed using dynamic light scattering and scanning electron microscopy. The results indicated that SFEE can be applied for the preparation of PCL nanoparticles without agglomeration and in a comparatively short duration of only 1 h

Application of isothermal titration calorimetry in evaluation of protein–nanoparticle interactions

Nanoparticles (NPs) offer a number of advantages over small organic molecules for controlling protein behaviour inside the cell. Protein binding to the surface of NPs depends on their surface characteristics, composition and method of preparation (Mandal et al. in J Hazard Mater 248–249:238–245, 2013). It is important to understand the binding affinities, stoichiometries and thermodynamical parameters of NP–protein interactions in order to see which interaction will have toxic and hazardous consequences and thus to prevent it. On the other side, because proteins are on the brink of stability, they may experience interactions with some types of NPs that are strong enough to cause denaturation or significantly change their conformations with concomitant loss of their biological function. Structural changes in the protein may cause exposure of new antigenic sites, “cryptic” peptide epitopes, potentially triggering an immune response which can promote autoimmune disease (Treuel et al. in ACS Nano 8(1):503–513, 2014). Mechanistic details of protein structural changes at NP surface have still remained elusive. Understanding the formation and persistence of the protein corona is critical issue; however, there are no many analytical methods which could provide detailed information about the NP–protein interaction characteristics and about protein structural changes caused by interactions with nanoparticles. The article reviews recent studies in NP–protein interactions research and application of isothermal titration calorimetry (ITC) in this research. The study of protein structural changes upon adsorption on nanoparticle surface and application of ITC in these studies is emphasized. The data illustrate that ITC is a versatile tool for evaluation of interactions between NPs and proteins. When coupled with other analytical methods, it is important analytical tool for monitoring conformational changes in proteins

Thermodynamic study of interactions between ZnO and ZnO binding peptides using isothermal titration calorimetry

Whilst material specific peptide binding sequences have been identified using a combination of combinato-rial methods and computational modelling tools, a deep molecular level understanding of the fundamental principles through which these interactions occur and in some instances modify the morphology of inorganic materials is far from being fully realized. Understanding the thermodynamic changes that occur during peptide-inorganic interactions and correlating these to structural modifications of the inorganic materials could be the key to achieving and mastering con-trol over material formation processes. This study is a detailed investigation applying isothermal titration calorimetry (ITC) to directly probe thermodynamic changes that occur during interaction of ZnO binding peptides (ZnO-BPs) and ZnO. The ZnO-BPs used are reported sequences G-12 (GLHVMHKVAPPR), GT-16 (GLHVMHKVAPPR-GGGC) and alanine mutants of G-12 (G-12A6, G-12A11 and G-12A12) whose interaction with ZnO during solution synthesis studies have been extensively investigated. The interactions of the ZnO-BPs with ZnO yielded biphasic isotherms comprising both an endo-thermic and an exothermic event. Qualitative differences were observed in the isothermal profiles of the different pep-tides and ZnO particles studied. Measured ΔG values were between -6 and -8.5 kcal/mol and high adsorption affinity val-ues indicated the occurrence of favourable ZnO-BP-ZnO interactions. ITC has great potential in its use to understand peptide-inorganic interactions and with continued development, the knowledge gained may be instrumental for simplifi-cation of selection processes of organic molecules for the advancement of material synthesis and design

Simple scoring system to predict in-hospital mortality after surgery for infective endocarditis

BACKGROUND: Aspecific scoring systems are used to predict the risk of death postsurgery in patients with infective endocarditis (IE). The purpose of the present study was both to analyze the risk factors for in-hospital death, which complicates surgery for IE, and to create a mortality risk score based on the results of this analysis. METHODS AND RESULTS: Outcomes of 361 consecutive patients (mean age, 59.1\ub115.4 years) who had undergone surgery for IE in 8 European centers of cardiac surgery were recorded prospectively, and a risk factor analysis (multivariable logistic regression) for in-hospital death was performed. The discriminatory power of a new predictive scoring system was assessed with the receiver operating characteristic curve analysis. Score validation procedures were carried out. Fifty-six (15.5%) patients died postsurgery. BMI >27 kg/m2 (odds ratio [OR], 1.79; P=0.049), estimated glomerular filtration rate 55 mm Hg (OR, 1.78; P=0.032), and critical state (OR, 2.37; P=0.017) were independent predictors of in-hospital death. A scoring system was devised to predict in-hospital death postsurgery for IE (area under the receiver operating characteristic curve, 0.780; 95% CI, 0.734-0.822). The score performed better than 5 of 6 scoring systems for in-hospital death after cardiac surgery that were considered. CONCLUSIONS: A simple scoring system based on risk factors for in-hospital death was specifically created to predict mortality risk postsurgery in patients with IE

QUALITY OF WATERS OF AQUIFER WEBS OF BISKRA REGION

<p>Controlling the quality of water distributed together with sound resource management is a factor of economic and social development. Also, the chemistry and knowledge of geological and hydrogeological aquifer, the object of this work, we identify the water quality examined through physical-chemical parameters. The study of these parameters more precisely the region of Biskra reveals a generally high mineralized whose origin is essentially the geological nature of enclosing land. However, the waters of the continental interlayer (Albian) are the chemical profile weakest; however, its high temperature makes it difficult to use both to supply drinking water as well as for irrigation. After synthesis of the results for different sheets (groundwater, Miopliocene, Eocene, Albian), the limestone is most interesting at least for drinking water, part of its rate of mineralization (medium), the acceptable temperature (24°C) and its relatively low salinity    (1 to 3 g/l). However, these waters are not used directly for human consumption. They requires further treatment.</p

Interaction of chitosan/lecithin nanoparticles with the rat intestinal tissue

To investigate the permeation of the anti-estrogenic drug tamoxifen through rat intestinal mucosa from tamoxifen-loaded chitosan/lecithin nanoparticles (TAM-NCL) and to study the role of bioadhesion and enzymatic degradation of the TAMNCL in the permeation experiment through the rat intestinal mucus