Methodenoptimierung und -validierung zur NIR-spektroskopischen Analyse von Schokolade, kakaohaltiger Fettglasur und Backmassen

In der Masterarbeit zum Thema "Methodenoptimierung und -validierung zur NIR-spektroskopischen Analyse von Schokolade, kakaohaltiger Fettglasur und Backmassen" geht es im Allgemeinen um die Einsetzbarkeit der Nahinfrarotspektroskopie (NIRS) als Screeningmethode zur analytischen Bestimmung der Zusammensetzung von Schokolade. Die Parameter Fett- und Theobromin-/Coffeingehalt und die Anteile an Saccharose und Laktose werden näher betrachtet. Zum Nachweis der Eignung der NIRS werden 104 Schokoladenproben auf die genannten Parameter über die Referenzanalytik nach der Amtlichen Sammlung nach § 64 LFGB analysiert und jeweils mittels eines Nahinfrarot-Photospektrometers gemessen. Die jeweils ermittelten Ergebnisse werden auf ihren Zusammenhang zueinander geprüft und mittel statistischer Tests ausgewertet. Anhand der Statistikdaten kann eine Angabe zur Einsetzbarkeit der NIRS als Schnellmethode erfolgen. Dieser Bereich umfasst die Methodenvalidierung der NIRS gegenüber der standardisierten nasschemischen Analytik und stellt den Hauptteil dieser Arbeit dar. Die NIRS bietet die Vorteile, dass keine aufwendige Probenvorbereitung zu erfolgen hat und keine Chemikalien einzusetzen sind. Zudem ist eine Probenmessung nach einmaliger Einweisung direkt durchführbar und dauert nur wenige Sekunden. Ein weiterer Aspekt der Arbeit ist die Verwendung der NIRS zur Differenzierung zwischen verschiedenen Lebensmitteln (LM). Hintergrund stellt hierbei der Schutz vor Täuschung nach Art. 7 LMIV in Verbindung mit § 11 LFGB und damit das in Verkehr bringen nachgemachter LM dar, was nach § 11 Abs. 2 Nr. 2 LFGB verboten ist. Untersucht wird hierbei die Möglichkeit der Differenzierung zwischen Schokolade und kakaohaltiger Fettglasur sowie zwischen Marzipan und Persipan. Jeweils letztere genannte LM stellen nachgemachte LM zu den ersteren dar. Über die Messung der Proben werden Absorptionsspektren erhalten, welche visuell auf Unterschiede und Ähnlichkeiten hin überprüft werden. Zusätzlich zu den Probenmessungen durch die NIRS werden die genannten LM im Rahmen der Produktdifferenzierung auch mit einem Photospektrometer des mittleren Infrarotbereiches gemessen. Hintergrund ist selbiger bereits erwähnter und biete den weiteren Vorteil, dass absolut keine Vorbereitung der zu untersuchenden Proben notwendig ist. Für die Parameter Fett- und Saccharosegehalt in Schokolade kann aufgrund der gewonnenen Erkenntnisse die NIRS als Screeningmethode eingesetzt werden. Für die Gehalte an Theobromin/Coffein und Laktose ist dies nicht anwendbar. Der Einsatz der NIRS zur qualitativen LM-Differenzierung ist im Fall von Schokolade/Fettglasur nicht möglich. Für Marzipan/Persipan kann der Einsatz evtl. erfolgen, jedoch liegen hier nicht ausreichend Informationen vor, um eine eindeutige Aussage treffen zu können.This master thesis about the topic "method optimization and validation for NIR spectroscopic analysis of chocolate, containing cocoa glaze and baking compositions" deals generally with the applicability of the near-infrared spectroscopy (NIRS) as a screening method for the analytical determination of the composition of chocolate. The parameters fat and theobromine/ caffeine content and the proportions of sucrose and lactose are considered in more detail. To demonstrate the suitability of the NIRS 104 chocolate samples are analyzed on the above mentioned parameters by the reference method of the Official Compilation according to § 64 LFGB and each sample is measured by a near-infrared spectrophotometer. The results determined in each case are tested for their relationship to each other and evaluated means of statistical tests. Based on the statistical data a decision can be given about the specifying of usability of NIRS as a rapid method. This part covers the method validation of NIRS opposite to the standardized wet chemical analysis and represents the major part of this work. The NIRS has the advantage that there is no complex sample preparation needed and no chemicals should be used. In addition, a sample measurement is directly carried out after a single instruction and takes only a few seconds. Another aspect of the work is the use of the NIRS for the differentiation between different foods. Background represents the protection of fraud under Art. 7 LMIV in conjunction with § 11 LFGB and therefore the placing of imitated food on the market, which is prohibited according to § 11 para. 2 no. 2 LFGB. The possibility of differentiation between chocolate and containing cocoa glaze and between marzipan and persipan will be examined. In each case, the latter mentioned food represents an imitated food of the first mentioned. The absorption spectra which are obtained by the measuring are visually checked for similarities and differences. In addition to the sample measurements by the NIRS the samples are measured as part of product differentiation with a spectrophotometer of the mid-infrared range. It is based on the already mentioned background and offers the additional advantage that absolutely no preparation of the sample is necessary for examination. Based on the findings, the NIRS can be used as a screening method for the parameters of fat and sucrose in chocolate. For the contents of theobromine/caffeine and lactose, this method is not applicable. The use of the NIRS for qualitative differentiation is not possible in the case of chocolate/cocoa containing fat glaze. The use for marzipan/persipan can be carried out if necessary, but there are not enough information available for an unequivocal statement

The sodium chloride complex catena-poly[[{μ3-2-[bis(2-hydroxyethyl)amino]ethan-1-ol}sodium] chloride], N(CH2CH2OH)3·NaCl

The reaction of sodium chloride with 2-[bis(2-hydroxyethyl)amino]ethan-1-ol results in the formation of the title salt {[Na{N(CH2CH2OH)3}]Cl}n. The polymeric structure is characterized by a sodium cation coordinated by one nitrogen and five oxygen atoms in a distorted octahedral environment. The resulting one-dimensional {—O—Na—O—Na—O}— coordination polymer extends parallel to [010] and is connected through the chloride counter-anion via O—H...Cl hydrogen bonding, giving rise to a two-dimensional supramolecular structure parallel to (001)

Influence of oxygen tension on dopaminergic differentiation of human fetal stem cells of midbrain and forebrain origin

Neural stem cells (NSCs) constitute a promising source of cells for transplantation in Parkinson's disease (PD), but protocols for controlled dopaminergic differentiation are not yet available. Here we investigated the influence of oxygen on dopaminergic differentiation of human fetal NSCs derived from the midbrain and forebrain. Cells were differentiated for 10 days in vitro at low, physiological (3%) versus high, atmospheric (20%) oxygen tension. Low oxygen resulted in upregulation of vascular endothelial growth factor and increased the proportion of tyrosine hydroxylase-immunoreactive (TH-ir) cells in both types of cultures (midbrain: 9.1±0.5 and 17.1±0.4 (P<0.001); forebrain: 1.9±0.4 and 3.9±0.6 (P<0.01) percent of total cells). Regardless of oxygen levels, the content of TH-ir cells with mature neuronal morphologies was higher for midbrain as compared to forebrain cultures. Proliferative Ki67-ir cells were found in both types of cultures, but the relative proportion of these cells was significantly higher for forebrain NSCs cultured at low, as compared to high, oxygen tension. No such difference was detected for midbrain-derived cells. Western blot analysis revealed that low oxygen enhanced β-tubulin III and GFAP expression in both cultures. Up-regulation of β-tubulin III was most pronounced for midbrain cells, whereas GFAP expression was higher in forebrain as compared to midbrain cells. NSCs from both brain regions displayed less cell death when cultured at low oxygen tension. Following mictrotransplantation into mouse striatal slice cultures predifferentiated midbrain NSCs were found to proliferate and differentiate into substantial numbers of TH-ir neurons with mature neuronal morphologies, particularly at low oxygen. In contrast, predifferentiated forebrain NSCs microtransplanted using identical conditions displayed little proliferation and contained few TH-ir cells, all of which had an immature appearance. Our data may reflect differences in dopaminergic differentiation capacity and region-specific requirements of NSCs, with the dopamine-depleted striatum cultured at low oxygen offering an attractive micro-environment for midbrain NSCs. © 2014 Krabbe et al.Danish Centre for Stem Cell Research. Work at AMS laboratory was supported by MINECO grants PLE2009-0101 and SAF2010-17167, and CAM S2011-BMD-2336 (Neurostem-CM). CH was supported by grants from the Danish National Research Foundation, the Lundbeck Foundation and the Danish Council for Strategic Research (Program Commission on Strategic Growth Technologies)Peer Reviewe

The sodium chloride complex catena-poly[[{μ3-2-[bis(2-hydroxyethyl)amino]ethan-1-ol}sodium] chloride], N(CH2CH2OH)3·NaCl

The reaction of sodium chloride with 2-[bis­(2-hy­droxy­eth­yl)amino]­ethan-1-ol results in the formation of the title salt {[Na{N(CH2CH2OH)3}]Cl}n. The polymeric structure is characterized by a sodium cation coordinated by one nitro­gen and five oxygen atoms in a distorted octa­hedral environment. The resulting one-dimensional {—O—Na—O—Na—O}— coordination polymer extends parallel to [010] and is connected through the chloride counter-anion via O—H...Cl hydrogen bonding, giving rise to a two-dimensional supra­molecular structure parallel to (001)

Comparative Analysis of Spontaneous and Stimulus-Evoked Calcium Transients in Proliferating and Differentiating Human Midbrain-Derived Stem Cells

Spontaneous cytosolic calcium transients and oscillations have been reported in various tissues of nonhuman and human origin but not in human midbrain-derived stem cells. Using confocal microfluorimetry, we studied spontaneous calcium transients and calcium-regulating mechanisms in a human ventral mesencephalic stem cell line undergoing proliferation and neuronal differentiation. Spontaneous calcium transients were detected in a large fraction of both proliferating (>50%) and differentiating (>55%) cells. We provide evidence for the existence of intracellular calcium stores that respond to muscarinic activation of the cells, having sensitivity for ryanodine and thapsigargin possibly reflecting IP3 receptor activity and the presence of ryanodine receptors and calcium ATPase pumps. The observed calcium transient activity potentially supports the existence of a sodium-calcium antiporter and the existence of calcium influx induced by depletion of calcium stores. We conclude that the cells have developed the most important mechanisms governing cytosolic calcium homeostasis. This is the first comparative report of spontaneous calcium transients in proliferating and differentiating human midbrain-derived stem cells that provides evidence for the mechanisms that are likely to be involved. We propose that the observed spontaneous calcium transients may contribute to mechanisms involved in cell proliferation, phenotypic differentiation, and general cell maturation

Characterization of Meteorin-An Evolutionary Conserved Neurotrophic Factor

Growth factors control cellular growth, proliferation, and differentiation and may have therapeutic applications. In this study, we focus on Meteorin which is a member of a largely uncharacterized evolutionary conserved two-member growth factor family. Our analysis shows that Meteorin is expressed in the central nervous system both during development and in adult mice. Detailed immunohistological analysis of the adult mouse brain reveals that Meteorin is highly expressed in Bergmann glia and in a few discrete neuronal populations residing in the superior colliculus, the ocular motor nucleus, the raphe and pontine nuclei, and in various thalamic nuclei. In addition, low levels of Meteorin is found in astrocytes (S100 beta+, OX42-) distributed ubiquitously throughout the brain. Meteorin was cloned and recombinant protein purified allowing N-terminal sequencing and mass spectrometric analysis showing that Meteorin is secreted as an unmodified monomer. This form is bioactive as it induces neurite outgrowth from dorsal root ganglions in vitro. Intrastriatal protein injection and lentiviral studies in vivo showed that Meteorin is a highly diffusible molecule in the brain and cellular uptake is apparent in specific populations which may carry the receptor. In summary, we provide a comprehensive expression analysis and have made and thoroughly validated molecular tools to help investigate the therapeutic potential of Meteorin