Characterization of hybrid materials by means of inverse gas chromatography and chemometrics

The surface properties of hybrid materials (potential carriers for sustained release of active agents) have been examined by inverse gas chromatography (IGC). A nonsteroidal antiinflammatory agent – ibuprofen was used as a model for active compound. The following parameters have been used to characterize the interactions between the constituents of the hybrid material and the active agent: dispersive component of the surface free energy D S g , KA and KD parameters describing the acidity and basicity, respectively, and Flory-Huggins parameter ' 23 c (the magnitude of interactions). Principal component analysis (PCA) and the procedure based on sum of ranking differences (SRD) were applied for selection of hybrid materials and parameters for characterization of these materials. One loose cluster found by PCA grouping of hybrid materials is refined by SRD analysis: SRD grouping indicates three groups having somewhat dissimilar properties

Quantifying non-specific interactions via liquid chromatography

Determinations of solute-cosolute interactions from chromatography have often resulted in problems, such as the “antibinding” (or a negative binding constant) between the solute and micelle in micellar liquid chromatography (MLC) or indeterminacy of salt-ligand binding strength in high-performance affinity chromatography (HPAC). This shows that the stoichiometric binding models adopted in many chromatographic analyses cannot capture the non-specific nature of solvation interactions. In contrast, an approach using statistical thermodynamics handles these complexities without such problems and directly links chromatographic data to, for example, solubility data via a universal framework based on Kirkwood-Buff integrals (KBI) of the radial distribution functions. The chromatographic measurements can now be interpreted within this universal theoretical framework that has been used to rationalize small solute solubility, biomolecular stability, binding, aggregation and gelation. In particular, KBI analysis identifies key solute-cosolute interactions, including excluded volume effects. We present (i) how KBI can be obtained directly from the cosolute concentration dependence of the distribution coefficient, (ii) how the classical binding model, when used solely as a fitting model, can yield the KBIs directly from the literature data, and (iii) how chromatography and solubility measurements can be compared in the unified theoretical framework provided via KBIs without any arbitrary assumptions about the stationary phase. To perform our own analyses on multiple datasets we have used an “app”. To aid readers’ understanding and to allow analyses of their own datasets, the app is provided with many datasets and is freely available on-line as an open-source resource

Additives for Abrasive Materials

The overarching objective of the chapter is to acquaint the readers with the topic associated with the production of abrasive tools and presentation of the most significant research results regarding the determination of the most important functional properties of selected additives (described in the literature and established on the basis of authors’ own scientific experiences). The studies regarding various additives, which were characterized in detail in the literature, were mainly based on thorough physicochemical and microstructural analysis as well as the determination of basic strength and thermos-mechanic parameters. The attempt to implement alternative cross-linking agents, which would result in the limited release of volatile organic compounds, is also of great importance in terms of production of environmentally friendly final products. A subsequent aim is to attract the attention of a wide range of readers and popularize the topic associated with conventional abrasive materials and next-generation abrasive compositions

Best conditions for biodegradation of diesel oil by chemometric tools

Diesel oil biodegradation by different bacteria-yeast-rhamnolipids consortia was tested. Chromato - graphic analysis of post-biodegradation residue was completed with chemometric tools (ANOVA, and a novel ranking procedure based on the sum of ranking differences). These tools were used in the selection of the most effective systems. The best results of aliphatic fractions of diesel oil biode - gradation were observed for a yeast consortia with Aeromonas hydrophila KR4. For these systems the positive effect of rhamnolipids on hydrocarbon biodegradation was observed. However, rham- nolipids addition did not always have a positive influence on the biodegradation process ( e.g. in case of yeast consortia with Stenotrophomonas maltophila KR7). Moreover, particular differences in the degradation pattern were observed for lower and higher alkanes than in the case with C22. Normally, the best conditions for “lower” alkanes are Aeromonas hydrophila KR4 + emulsifier independently from yeasts and e.g. Pseudomonas stutzeri KR7 for C24 alkane

Crystalline Zeolite Layers on the Surface of Titanium Alloys in Biomedical Applications: Current Knowledge and Possible Directions of Development

In this review, the main focus was on the use of zeolites as layers to modify the surface of titanium implants. The article discusses the basic methods for modifying the functional properties of zeolites (e.g., ion exchange) as well as biomedical applications of zeolites (e.g., drug delivery systems and biosensors). The article reviews the surface modifications of titanium alloys prepared so far with the use of various types of zeolites and selected examples are presented. This review shows the significant impact of titanium surface modification with zeolites, as well as their post-synthetic modification on implant properties, for instance, better biocompatibility, faster osseointegration, better cell adhesion, and corrosion resistance properties. The results of the research presented so far in this review show that the modification of titanium with zeolite layers is a very prospective subject, but underdeveloped, as evidenced by a small number of studies on this subject. We have shown that the prepared layers can be continuously improved and used, e.g., as local delivery systems for various active pharmaceutical ingredients (APIs). We hope that the prepared review will help research groups around the world in the preparation of implants modified with zeolites with even better properties and utility applications

Crystalline Zeolite Layers on the Surface of Titanium Alloys in Biomedical Applications: Current Knowledge and Possible Directions of Development

In this review, the main focus was on the use of zeolites as layers to modify the surface of titanium implants. The article discusses the basic methods for modifying the functional properties of zeolites (e.g., ion exchange) as well as biomedical applications of zeolites (e.g., drug delivery systems and biosensors). The article reviews the surface modifications of titanium alloys prepared so far with the use of various types of zeolites and selected examples are presented. This review shows the significant impact of titanium surface modification with zeolites, as well as their post-synthetic modification on implant properties, for instance, better biocompatibility, faster osseointegration, better cell adhesion, and corrosion resistance properties. The results of the research presented so far in this review show that the modification of titanium with zeolite layers is a very prospective subject, but underdeveloped, as evidenced by a small number of studies on this subject. We have shown that the prepared layers can be continuously improved and used, e.g., as local delivery systems for various active pharmaceutical ingredients (APIs). We hope that the prepared review will help research groups around the world in the preparation of implants modified with zeolites with even better properties and utility applications