Analytische Chemie
Filtern
Erscheinungsjahr
- 2012 (4) (entfernen)
Dokumenttyp
- Zeitschriftenartikel (4) (entfernen)
Schlagworte
- BSA (1)
- Bio-interface (1)
- Drug discovery (1)
- Editorial (1)
- Environmental analysis (1)
- Giant magneto resistance (1)
- Lead identification (1)
- Lessing (1)
- Magnetic flux leakage (1)
- Nanosilica hybrids (1)
A facile and versatile synthetic route for controlling the size and surface potential of organic–inorganic hybrid silica nanoparticles (NPs) is introduced in this paper. For polymer-grafted NPs, the density of polymer chains on the surface is strongly affected by the concentration of precursor. Nevertheless, for condensed NPs, the precursor concentration determines the particle size but not the density of polymer chains on the surface or the adsorption of bovine serum albumin (BSA). Results presented here may have Major implications in biomedical and colloidal chemistry since interfacial and colloidal properties are known to drive several processes associated with nanoparticles in biological media.
Im Rahmen der Herstellung und Überwachung von Arzneimitteln käme wohl niemand – außer dem alten Paracelsus – auf die Idee, diese Aussage in irgendeiner Form anzuzweifeln. Zeit, der Pharmazeutischen Industrie endlich einmal ein Kompliment zu machen. Danke zu sagen, für die technisch, wissenschaftliche Kultur, die fast für jede Krankheit etwas parat hat und uns, unserer Familie, unseren Freunden ein unbeschwertes und langes Leben ermöglicht. Leute, verkauft Euch doch nicht immer so schlecht!
GMR sensors are widely used in many industrial segments such as information technology, automotive, automation and production, and safety applications. Each area requires an adaption of the sensor arrangement in terms of size adaption and alignment with respect to the field source involved. This paper deals with an analysis of geometric sensor parameters and the arrangement of GMR sensors providing a design roadmap for non-destructive testing (NDT) applications. For this purpose we use an analytical model simulating the magnetic flux leakage (MFL) distribution of surface breaking defects and investigate the flux leakage signal as a function of various sensor parameters. Our calculations show both the influence of sensor length and height and that when detecting the magnetic flux leakage of µm sized defects a gradiometer base line of 250 µm leads to a signal strength loss of less than 10% in comparison with a magnetometer response. To validate the simulation results we finally performed measurements with a GMR magnetometer sensor on a test plate with artificial µm-range cracks. The differences between simulation and measurement are below 6%. We report on the routes for a GMR gradiometer design as a basis for the fabrication of NDT-adapted sensor arrays. The results are also helpful for the use of GMR in other application when it comes to measure positions, lengths, angles or electrical currents.
A unifying review of bioassay-guided fractionation, effect-directed analysis and related techniques
(2012)
The success of modern methods in analytical chemistry sometimes obscures the problem that the ever increasing amount of analytical data does not necessarily give more insight of practical relevance. As alternative approaches, toxicity- and bioactivity-based assays can deliver valuable information about biological effects of complex materials in humans, other species or even ecosystems. However, the observed effects often cannot be clearly assigned to specific chemical compounds. In these cases, the establishment of an unambiguous cause-effect relationship is not possible. Effect-directed analysis tries to interconnect instrumental analytical techniques with a biological/biochemical entity, which identifies or isolates substances of biological relevance. Successful application has been demonstrated in many fields, either as proof-of-principle studies or even for complex samples. This review discusses the different approaches, advantages and limitations and finally shows some practical examples. The broad emergence of effect-directed analytical concepts might lead to a true paradigm shift in analytical chemistry, away from ever growing lists of chemical compounds. The connection of biological effects with the identification and quantification of molecular entities leads to relevant answers to many real life questions.