The present work related to apply hot-melt ink-jet process for imaging at offset lithographic printing form, to utilise a reusable surface for many times and particularly related to validating thermal and ultrasonic erasing processes. This dissertation investigated systematically the role of certain factors towards affecting erasing image area process on print surfaces. Thermal erasing process approved to melt and suck the image area from the surface, the results were adopted by using contact angle measurements and scanning electron microscope. Ultrasonic erasing process permitted to solve the image area by choosing erasing chemistries, influence of selected erasing chemistries on printing surface, and evaluation the process, the results were tested by UV/Vis spectrometer, contact angle, profileometery and visual microscope. / Der Fortschritt im Bereich von Charakterisierung und Verständnis für Hot-melt Ink Jet Prozesse zur Bebilderung von Offsetdruckform-Zylindern ist ein Ergebnis dieser Forschung. Die Systematik dieser Arbeit basiert auf einem theoretischen Teil, um einen geeigneten Löschprozess auszuwählen. Der Löschprozess hängt von den Eigenschaften des Hot-melt Ink Jet Materials und der genutzten Aluminiumdruckoberfläche ab. Diese werden systematisch im Labormaßstab experimentell untersucht. Der thermische Prozess wurde einerseits durch Benetzbarkeitsprüfungen und anderseites durch Rasterelektronmikroskopaufnahmen bewertet.Der Ultraschallprozess ist ein nasser Löschprozess. Die Untersuchungen wurden in vier Stufen systematisch durchgeführt - Auswahl vom geeigneten Lösungsmitteln - Einflüsse von ausgewählten Lösungsmitteln auf nicht beschichtete und beschichtete Aluminium platten - Evaluation eines Ultraschalllöschprozesses - Validation eines Löschprozesses; zur Bewertung des Löschprozesses wurden mehrere Druckplattenproben bebildert und gelöscht Die Ergebnisse wurden durch UV/Vis Spektrometer, Kontaktwinkel, Profiliometrie und Visuelle Mikroskopie getestet.

Im Rahmen dieser Arbeit wurden Siliciumkomplexe mit dianionischen Pyrrol-2-carbaldimin-funktionalisierten N,N,O- und N,N,N,N-Chelatliganden synthetisiert und kristallografisch, NMR- und UV/Vis-spektroskopisch und mittels quantenchemischer Berechnungen charakterisiert. Die pentakoordinierten Si-Komplexe mit N,N,O-Ligandrückgraten wiesen in Abhängigkeit von den weiteren Si-gebundenen Substituenten unterschiedlich konfigurierte verzerrt trigonal-bipyramidale Si-Koordinationssphären auf. Die Ursache der Farbigkeit dieser Verbindungen konnte mittels quantenchemischer Berechnungen detailliert erklärt werden. – Die Si-Komplexe mit N,N,N,N-Ligandrückgraten liegen in Abhängigkeit von den weiteren Si-gebundenen Substituenten als 5-fach koordinierte kationische oder neutrale 6-fach koordinierte Si-Komplexe vor. Deren Farbigkeit wurde mittels UV/VIS-Spektroskopie untersucht. Von ausgewählten Komplexen wurden die Tensoren der 29Si-NMR-Verschiebung rechnerisch und CP/MAS-NMR-spektroskopisch bestimmt.

This Diploma thesis was focused on the degradation of dyes Saturn Red L4B (Direct Red 79) and Saturn Blue LB (Direct Blue 106) by DC diaphragm discharge (DC-DD). Supplied power was between 160 and 180 W. Conductivity and pH were changing at each electrode area during the DC diaphragm discharge, therefore the effect of pH and conductivity changes on the dye solution itself were examined. All samples were measured by UV-VIS spectrometer in the wavelength range of 300–800 nm. No significant dependence of dye absorption spectra on conductivity was observed, while pH significantly affected the absorption curves of dyes. Ageing of dye spectra showed significant changes of Saturn Red L4B. Next task was the comparison of dyes destruction efficiency by DC-DD, audiofrequency diaphragm discharge (AF-DD) and electrolysis. Dye decomposition by AF-DD was not observed at set conditions (voltage of 80–120 V, current of 2.2 A and frequency of 2 kHz). In the case of DC diaphragm discharge the electrolysis played an important role. Decomposition efficiency of the dyes by electrolysis was up to 15 %. The pumping effect in the DC diaphragm discharge was also investigated. Although the individual electrode areas were linked only by a small pinhole in a nonconductive barrier (the pinhole diameter of 0.3 mm), solutions of the anode and cathode compartment interacted with each other up to 10 %. Finally, the degradation products of Saturn Red L4B treated by DC-DD in two electrodes parts are also described. Decomposition products were determined by high performance liquid chromatography (HPLC) combined with the mass spectrometer.

A series of para-substituted acetophenones bearing a furanyl or a thiophenyl moiety show a large Stokes-shift, which is a function of various solvent properties. Photophysical properties such as emission lifetime of the compounds have been determined using time-correlated-single photon counting to secure the intrinsic fluorescence behaviour. The solvent dependent position of the UV/Vis emission band [small nu, Greek, tilde]max,em of the compounds has been measured in 26 various solvents. The influence of the solvent on [small nu, Greek, tilde]max,em is of very complex nature and mathematically analysed by multiple square linear solvation energy (LSE)-correlation analysis using Catalán's four-solvent parameter set. Solvent acidity has a strong influence on the bathochromic shift of 2,5-disubstituted furan derivatives compared to the non-5-substituted furan and thiophene derivatives, which show a contrary behaviour. Therefore, the 5-cyanofuranyl-substituted acetophenone derivative is useful as a probe for measuring environmental properties by fluorescence spectroscopy. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Das aus dem Apoprotein Opsin und dem kovalent gebundenen Liganden bestehende Rhodopsin dient als Modellsystem für den Aktivierungsmechanismus der größten Klasse von G-Protein-gekoppelten Rezeptoren (GPCR). Infolge einer photochemischen Reaktion vollführt Rhodopsin eine Bewegungsabfolge von Sekundärstrukturelementen, wodurch es aktiviert wird, das G-Protein bindet und den Stimulus auf zellinterne Signalwege überträgt. Mithilfe der ortsspezifischen Mutagenese wurden Mutanten des bovinen Rhodopsins erzeugt, in eine künstliche Lipidumgebung eingelagert und hauptsächlich mittels FTIR-Spektroskopie untersucht. Anhand der Y191F- und Y192F-Mutanten konnte die Translokation des transienten Gegenions der Schiffschen Base Glu181 während der Aktivierung bestimmt werden. Die Interaktionen des Tyr206 sind für die gekoppelte Bewegung von EL2 und TM5 mitbestimmend, was mittels Y206F-Mutante gezeigt wurde. Eine Anhäufung von Methioninen auf der cytoplasmatischen Seite des Rezeptors ist u.a. für das Ausklappen der TM6 zuständig. Diese Bewegung ist wichtige Determinante der Rezeptoraktivierung. Hierfür wurden insgesamt fünf Mutanten verwendet. Im zweiten, hauptsächlichen Teil der Arbeit wird das bislang kaum untersuchte humane Rhodopsin mit dem bovinen Rezeptor verglichen. Ausgehend von verschiedenen Dunkelzuständen, konnte gezeigt werden, dass die Aktivierungsmechanismen beider Rezeptoren voneinander divergieren, um letztlich bei der Bildung der aktiven Spezies wieder zu konvergieren. Über die Analyse der Aminosäuresequenzen der Mammalia-Rhodopsine wurden zwei Bereiche hoher Variabilität identifiziert, die u.a. die molekulare Ursache für diese Diskrepanzen liefern. Diese Feststellung wurde mit human-bovinen-Rhodopsinchimären bewiesen. Ergänzend zu dieser Studie wurde Schafsrhodopsin einem Vergleich sowohl mit bovinem als auch mit humanem Rezeptor unterzogen. Es zeigte, als eine weitere natürlich vorkommende Variante des Lichtrezeptors, einen eigenständigen Weg der Aktivierung. / Rhodopsin, which consists of the apoprotein opsin and its covalently bound ligand, is used as a model system to understand the activation mechanism of the large family of G protein coupled receptors (GPCRs). As a result of a photochemical reaction, rhodopsin undergoes activating structural changes, enabling it to bind the G protein and transmitting the stimulus to intracellular signaling pathways. In the first part of this work, site-directed mutants of bovine rhodopsin were produced, incorporated into an artificial lipid environment, and studied mainly by FTIR spectroscopy. The translocation of the transient Schiff base counterion (Glu181) during the activation process was determined using the Y191F- and Y192F-mutants. The interactions of Tyr206 contributed to the coupled movement of EL2 and TM5, which was shown by Y206F-mutant. A striking accumulation of methionines on the cytoplasmic side of the receptor was observed to be a key-player for the activating outward motion of TM6. In the second and primary part of this work, human rhodopsin, which has been rarely studied, was compared with the bovine receptor. Starting from various dark states, it was shown that the activation mechanisms of both receptors diverge from each other and yet ultimately converge in the formation of the active species. By analyzing the amino acid sequences of mammalian rhodopsins, two regions of high variability were identified, which provide the molecular basis for these discrepancies. This finding was verified by the investigation of human/bovine rhodopsin chimeras. In addition to this study, ovine rhodopsin was compared with both the bovine and human forms. It showed, as another naturally occurring variant of the light receptor, an independent pathway of activation.

Kanalrhodopsine (ChRs) sind lichtgesteuerte Ionenkanäle, welche nach Absorption eines Photons durch den Retinal-Cofaktor einen passiven Ionentransport über die Zellmembran katalysieren. Im Zuge von optogenetischen Anwendungen wird diese Reaktion für die Beeinflussung der Ionenhomöostase von verschiedenen Zelltypen und Geweben ausgenutzt. Zu Beginn dieser Arbeit wurden lichtinduzierte Strukturänderungen und Protontransferschritte in einem breiten Zeitbereich (Nanosekunden bis Minuten) in dem grün-absorbierenden ChR ReaChR mithilfe von stationärer und transienter UV-vis- und Fourier-Transform-Infrarot-Spektroskopie (FTIR) untersucht. Auf Basis der experimentellen Daten wurde ein komplexes Photozyklus-Modell konzipiert. Anschließend wurde die IR-aktive, nichtkanonische Aminosäure p-Azido-L-phenylalanin (azF) mittels Stopp-Codon-Suppression ortsspezifisch an mehreren Positionen innerhalb der vermuteten ionenleitenden Kanalpore in ReaChR inkorporiert und mit FTIR untersucht. azF ist sensitiv gegenüber Polaritätsänderungen und absorbiert in einem hochfrequenten Bereich (~2100 cm-1). Aufgrund der großen spektralen Separation zu endogenen Proteinschwingungen (< 1800 cm-1) können globale Konformations- und lokale Hydratisierungsänderungen simultan detektiert werden. Die erhobenen Daten leisten einen wichtigen Beitrag zum Verständnis der Bildung einer temporären Wasserpore in ChRs und demonstrieren zum ersten Mal den erfolgreichen in-vivo-Einbau einer artifiziellen Aminosäure in mikrobielle Rhodopsine und dessen schwingungsspektroskopische Analyse. Die Methode bietet aufgrund ihrer hohen Ortsauflösung ein großes Potential für die Studie von Mikroumgebungen innerhalb komplexer Proteinensemble. / Channelrhodopsins (ChRs) are light-gated ion channels. Upon absorption of a photon, the retinal chromophore isomerizes and drives conformational changes within the protein, which lead to a passive ion transport across the cell membrane. This capability is used for optogenetic applications to manipulate ionic homeostasis of different cell types and entire organisms. Within the work, light-induced structural changes and proton transfer steps were studied in the green-absorbing ChR ReaChR in great detail by steady-state and transient UV-vis and Fourier transform infrared spectroscopy (FTIR). The data were merged into a complex photocycle model. Next, the IR-active, unnatural amino acid p-azido-L-phenylalanine (azF) was site-specifically introduced at several sites of the putative ion pore of ReaChR by stop codon suppression. azF is sensitive to polarity changes and absorbs in a clear spectral window lacking endogenous protein vibrations. Thus, FTIR measurements of labeled mutants report for global conformational changes (< 1800 cm-1) and local hydration changes (~2100 cm-1) simultaneously. The presented findings reveal crucial insights regarding formation of a transient water pore in ChRs and demonstrate the first report of the successful in-vivo incorporation of an artificial amino acid into a microbial rhodopsin and its subsequent spectroscopic investigation. Additionally, the so far unprecedented spatial resolution renders this methodology superior over conventional FTIR methods to study microenvironments within complex protein ensembles.

<p>In this thesis some multivariate spectroscopic methods for the analysis of solutions are proposed. Spectroscopy and multivariate data analysis form a powerful combination for obtaining both quantitative and qualitative information and it is shown how spectroscopic techniques in combination with chemometric data evaluation can be used to obtain rapid, simple and efficient analytical methods. These spectroscopic methods consisting of spectroscopic analysis, a high level of automation and chemometric data evaluation can lead to analytical methods with a high analytical capacity, and for these methods, the term high-capacity analysis (HCA) is suggested. It is further shown how chemometric evaluation of the multivariate data in chromatographic analyses decreases the need for baseline separation. </p><p>The thesis is based on six papers and the chemometric tools used are experimental design, principal component analysis (PCA), soft independent modelling of class analogy (SIMCA), partial least squares regression (PLS) and parallel factor analysis (PARAFAC). The analytical techniques utilised are scanning ultraviolet-visible (UV-Vis) spectroscopy, diode array detection (DAD) used in non-column chromatographic diode array UV spectroscopy, high-performance liquid chromatography with diode array detection (HPLC-DAD) and fluorescence spectroscopy. The methods proposed are exemplified in the analysis of pharmaceutical solutions and serum proteins.</p><p>In Paper I a method is proposed for the determination of the content and identity of the active compound in pharmaceutical solutions by means of UV-Vis spectroscopy, orthogonal signal correction and multivariate calibration with PLS and SIMCA classification. Paper II proposes a new method for the rapid determination of pharmaceutical solutions by the use of non-column chromatographic diode array UV spectroscopy, i.e. a conventional HPLC-DAD system without any chromatographic column connected. In Paper III an investigation is made of the ability of a control sample, of known content and identity to diagnose and correct errors in multivariate predictions something that together with use of multivariate residuals can make it possible to use the same calibration model over time. In Paper IV a method is proposed for simultaneous determination of serum proteins with fluorescence spectroscopy and multivariate calibration. Paper V proposes a method for the determination of chromatographic peak purity by means of PCA of HPLC-DAD data. In Paper VI PARAFAC is applied for the decomposition of DAD data of some partially separated peaks into the pure chromatographic, spectral and concentration profiles. </p>

La miniaturisation toujours plus poussée des composants électroniques a atteint une limite en arrivant à l’échelle atomique. Afin de fabriquer des circuits à cette échelle, il est nécessaire de intéresser aux plus petits composants pouvant être intégrés : les molécules individuelles et les groupes d’atomes. Dans cette optique, les molécules de 1,4-bis(pyridin-4-ylethynyl) benzène (BPEB), Dibenzo[a,h]thianthrene (DBTH), de Bis{82,92,152,162,222,232- hexa-(2,4,6-trifluorophenoxy)[g,l,q]-5,10,15,20-tetraazaporphyrino)}[b,e]-benzene (H4Pc2) ont été conçues, synthétisées et caractérisées afin d’en étudier le transport de charges et les changements induits proche de la surface. Des techniques de SPM, tels que le STM, le nc-AFM et l’usage conjoint de l’AFM avec le STM ont été mises en pratique pour analyser les molécules reposant intégralement ou partiellement sur un substrat. L’interprétation des résultats expérimentaux a été faite au moyen de calculs de DFT. De plus, l’autoassemblage en solution de nouvelles mono-phthalocyanines métalliques fluorées, MPc (M= Mg2+, 2H+, Co2+) a été étudié.Tout d’abord, les mesures de conductance mirent en évidence, lors d’expériences de manipulation de fils moléculaires (BEPB), les changements de conformation associés aux transport des électrons à travers les molécules. De plus, le mouvement dit de “retournement papillon” (anglais: butterfly flapping) ayant lieu dans la classe des thianthrènes fut bloqué à basse température grâce à l’interaction avec le substrat. Ce blocage a permit de conduire la première étude stéréochimique de dérivés de thianthrènes chiraux (DBTH). Les analyses STM du DBTH ont montrées que le passage entre deux configurations de DBTH est reproductible et non-destructif. Par ailleurs, le nc-AFM utilisé à résolution sub-moléculaire a constitué un outils important pour réaliser une caractérisation complète et distinguer entre les différents isomères de configuration et de constitution déposés sur une surface. D’autre part, la structure moléculaire de la phthalocyanine binucléaire (H4Pc2) a été confirmée en utilisant un STM en mode “courant constant” et un AFM en mode “fréquence constante”. Ces résultats jettent les bases d’une prochaine étude de transport (travail en cours). En outre, l’étude de l’agrégation dans les molécules de MPc mit en évidence le rôle important de la capacité de coordination de l’atome central de la cavité Pc sur la formation d’agrégat. Finalement, des mesures électrochimiques ont démontrées que l’agrégation moléculaire peut bloquer le nature active de l’atome Co2+. Dans ce travail, il a été clairement montré que le SPM est une technique adéquate pour étudier les changements de conformations et de configurations associés aux courant tunnel d’électrons à travers des molécules, qu’elles soient planaire ou pas. Les études d’agrégation des interrupteurs magnétiques ont permis de mieux comprendre l’organisation supramoléculaire. Cette organisation est un point crucial pour le développement de futurs circuits basés sur une fabrication “bottom-up”. / The demand of downscaling of technology will reach its limit at the atomic length scale. This claim creates the necessity of investigating the smallest components suitable to become devices, single molecules or group of atoms. Therefore, 1,4-bis(pyridin-4-ylethynyl) benzene (BPEB), Dibenzo[a,h]thianthrene (DBTH) and Bis{82,92,152,162,222,232-hexa-(2,4,6-trifluorophenoxy)[g,l,q]-5,10,15,20-tetraazaporphyrino)}[b,e]-benzene (H4Pc2) have been designed, synthesized and characterized to investigate transport of charge through molecules and surface confined molecular switching. Scanning Probe Microscopy (SPM), such as STM, nc-AFM and combined STM/AFM were used to study the molecules on near-surface conditions. Density Functional Theory (DFT) calculations were used to interpret the experimental results. Moreover, the self-assembly of new fluorinated metalo mono-phthalocyanines, MPc (M= Mg2+, 2H+, Co2+) was investigated in solution.Firstly, conductance experiments performed while a molecular wire (BPEB) was being lifted up from a surface revealed the conformational changes associated to the transport of electrons through molecules. Secondly, the “butterfly” flapping motion in the class of the thianthrenes was blocked due to the interaction with a surface at low temperature. This block leads to the first stereochemical study of a quiral thianthere derivative (DBTH). The STM experiments on DBTH revealed a reproducible and non-destructive switching between two surface confined configurations of DBTH. In addition, nc-AFM with submolecular resolution has been proved to be a powerful tool for the full characterization and distinction of configurational and constitutional isomers on surfaces. Thirdly, the molecular structure of a binuclear phthalocyanine (H4Pc2) was confirmed through constant current STM and constant high _f AFM experiments. These results set the state of future spintronic transport experiments (ongoing work). On the other hand, the aggregation studies on MPc revealed that the coordination character of the central atom of the Pc cavity has an important effect on the formation of aggregates. Additionally, electrochemical experiments demonstrated that molecular aggregations can lead to the quenching of the electrochemical-active nature of a Co2+ atom.Herein it has been demonstrated that SPM are suitable techniques to study the conformational and configurational changes associated with the tunneling of electrons through planar and non-planar molecules in real space. Aggregation studies of magnetic switches were carried out to better understand the supramolecular organization under near surface conditions, a key point for the design of future devices based on the bottom up approach.

In this work, an electrochemical method based on a cyt c biosensor has been developed, for the detection of selected arsenic and cyanide compounds. Boron Doped Diamond (BDD) electrode was used as a transducer, onto which cyt c was immobilised and used for direct determination of Prussian blue, potassium cyanide and arsenic trioxide by inhibition mechanism. The sensitivity as calculated from cyclic voltammetry (CV) and square wave voltammetry (SWV), for each analyte in phosphate buffer (pH= 7) was found to be (1.087- 4.488 ×10-9 M) and the detection limits ranging from 0.0043- 9.1 μM. These values represent a big improvement over the current Environmental Protection Agency (EPA) and World Health Organisation (WHO) guidelines.

In this thesis some multivariate spectroscopic methods for the analysis of solutions are proposed. Spectroscopy and multivariate data analysis form a powerful combination for obtaining both quantitative and qualitative information and it is shown how spectroscopic techniques in combination with chemometric data evaluation can be used to obtain rapid, simple and efficient analytical methods. These spectroscopic methods consisting of spectroscopic analysis, a high level of automation and chemometric data evaluation can lead to analytical methods with a high analytical capacity, and for these methods, the term high-capacity analysis (HCA) is suggested. It is further shown how chemometric evaluation of the multivariate data in chromatographic analyses decreases the need for baseline separation. The thesis is based on six papers and the chemometric tools used are experimental design, principal component analysis (PCA), soft independent modelling of class analogy (SIMCA), partial least squares regression (PLS) and parallel factor analysis (PARAFAC). The analytical techniques utilised are scanning ultraviolet-visible (UV-Vis) spectroscopy, diode array detection (DAD) used in non-column chromatographic diode array UV spectroscopy, high-performance liquid chromatography with diode array detection (HPLC-DAD) and fluorescence spectroscopy. The methods proposed are exemplified in the analysis of pharmaceutical solutions and serum proteins. In Paper I a method is proposed for the determination of the content and identity of the active compound in pharmaceutical solutions by means of UV-Vis spectroscopy, orthogonal signal correction and multivariate calibration with PLS and SIMCA classification. Paper II proposes a new method for the rapid determination of pharmaceutical solutions by the use of non-column chromatographic diode array UV spectroscopy, i.e. a conventional HPLC-DAD system without any chromatographic column connected. In Paper III an investigation is made of the ability of a control sample, of known content and identity to diagnose and correct errors in multivariate predictions something that together with use of multivariate residuals can make it possible to use the same calibration model over time. In Paper IV a method is proposed for simultaneous determination of serum proteins with fluorescence spectroscopy and multivariate calibration. Paper V proposes a method for the determination of chromatographic peak purity by means of PCA of HPLC-DAD data. In Paper VI PARAFAC is applied for the decomposition of DAD data of some partially separated peaks into the pure chromatographic, spectral and concentration profiles.