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- GC/MS (5)
- Polymers (4)
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- Pyrolysis (3)
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Analysis of Synthetic Polymers and Copolymers by Pyrolysis- Gas Chromatography/Mass Spectrometry
(2005)
Structural analysis and the study of degradation properties are important in order to understand and improve performance characteristics of synthetic polymers and copolymers in many industrial applications. Polymers/copolymers are inherently difficult to analyze because of their high molecular weight and lack of volatility. Traditionally, various analytical techniques are used to characterize polymers/copolymers including physical testing (rheological testing), thermogravimetric analysis (TGA), electron microscopy, Fourier transform infrared (FTIR) spectroscopy, size-exclusion chromatography (SEC)/gel permeation chromatography (GPC), and mass spectrometry (MS). Often, time consuming sample preparation, including hydrolysis, dissolution, or derivatization is needed before analysis.
Gas chromatography with flame-ionization detection (FID) and gas chromatography-mass spectrometry (GC/MS) has been used for structure elucidation of long-chain primary n-alkyl amines after derivatization with trifluoroacetic anhydride (TFAA). Electron impact ionization- (EI) and positive chemical ionization- (PCI) mass spectra of trifluoroacetylated derivatives of the identified nalkyl amines are presented. The corrosion inhibiting n-alkyl amines were applied in the investigation of a new anticorrosive and antifouling formulation for water-steam circuit of energy systems in the power industry. The presented results are part of an EU-funded international collaboration with partners from research institutes and industry from Poland, Lithuania, Romania, France and Germany (EUREKA project BOILTREAT E!2426).
Timely recognition of threats can be significantly supported by security assistance systems that work continuously in time and call the security personnel in case of anomalous events in the surveillance area. We describe the concept and the realization of an indoor security assistance system for real-time decision support. The system consists of a computer vision module and a person classification module. The computer vision module provides a video event analysis of the entrance region in front of the demonstrator. After entering the control corridor, the persons are tracked, classified, and potential threats are localized inside the demonstrator. Data for the person classification are provided by chemical sensors detecting hazardous materials. Due to their limited spatio-temporal resolution, a single chemical sensor cannot localize this material and associate it with a person. We compensate this deficiency by fusing the output of multiple, distributed chemical sensors with kinematical data from laser-range scanners. Considering both the computer vision formation and the results of the person classification affords the localization of threats and a timely reaction of the security personnel.
The ongoing miniaturization, multi-layer structure parts and hybrid parts require methods to determine mechanical properties on a micro-scale. However, there is a gap in measuring techniques. On one hand there are the classical methods to measure hardness e.g. VICKERS, ROCKWELL, UNIVERSAL, IRHD etc having resolutions typically above 100μm. On the other hand there are well-developed AFM methods that allow for the determination of mechanical properties in the nanometer range. This paper describes an indentation technique that yields data of mechanical properties in the micrometer range between typically 5 to 50 μm. The measuring device and the data evaluation is presented. Results of micro-mechanical mapping are shown for NR-SBR rubber interfaces, a fuel tank and a part manufactured by two component injection moulding. Finally, the measured micro-mechanical stiffness is compared to the YOUNG’s modulus of the corresponding materials.
Embryonic stem cells (ES) have the potential of long-term viability, selfrenewal and pluripotency which makes them interesting candidates for tissue engineering and gene therapy applications. On the other hand ethical and political issues arise while using theses cells and severe problems such as their tumorgenicity have not been solved yet. In the last couple of month a new source of cells with stem cell character was developed, the induced pluripotent stem cells (iPS). These cells are derived from differentiated adult cells via transduction of three transcription factors and show features similar to embryonic stem cells. Unfortunately, this includes the tumorgenicity which is even higher in those cells since the transcription factor transduction needed until now, is performed with retrovial vectors, which have a tumor potential on their own. Thus, adult stem cells are investigated extensively as alternative source of self-renewing cells. Human mesenchymal stem cells (HMSCs), which have in addition the advantage of potential autologous transplantation, can be found in various differentiated tissues since they are needed for maintenance and repair. They can be differentiated in chondrogenic, osteogenic, adipogenic and myogenic lineages which makes them an excellent tool for future tissue replacement strategies.
A method for the identification of polymeric residues in recycled aluminium by using analytical pyrolysis at 700°C hyphenated to gas chromatography-mass spectrometry (Py-GC/MS) was presented for the first time. The polymeric residues in recycled aluminium were identified as a mixture of polyethylene, polystyrene, and phenolic resin. The described method could be useful for the aluminium industry as a part of the quality control of the recycled aluminium production.
A soluble form of the complement receptor CD21 (sCD21) is shed from the lymphocyte surface. The sCD21 is able to bind all known ligands such as CD23, sCD23, Epstein-Barr virus and C3d in immune complexes. Here, we show the serum levels of sCD21 in sera the of antiphospholipid syndrome (APS) patients. Antiphospholipid syndrome is an autoimmune disorder in which autoantibodies cause heart attack, stroke and miscarriage. Antiphospholipid syndrome may appear as primary or in association with systemic lupus erythromatosus (SLE) and other autoimmune diseases. Here, we ask whether APS patients have different sCD21 titers compared to healthy persons and whether sCD21 levels correlate with the presence of anti-β2-GPI autoantibodies. We show that autoimmune APS patients have significantly reduced amounts of sCD21 in their sera, irrespective of the presence of anti-β2-GPI autoantibodies. In our APS patients cohort additional SLE, vasculities, DVT (deep vein thrombosis), fetal loss or thrombosis did not correlate to the reduced level of sCD21.
Polymerase Chain Reaction
(2011)
DNA Sequencing
(2011)