Relation Between Specific Ionization of Various Radiations and Their Relative Biological Effectiveness in Mammalian Systems

The relative biological effectiveness of several radiations of differing specific ionizations was determined. The radiation effect studied was impairment of bone marrow function, and the biological test system used was the depression of Fe59 uptake by the red blood cells of male Sprague-Dawley rats. The effectiveness of the mixed radiations in the thermal column of a homogeneous reactor was compared with 250-KVP X radiation, and the effect of the beta particles of tritium was compared with that of Co60 gamma rays. The effect of the alpha particles of Pu and Ra on bone marrow function was also determined

Crosspolarization with imperfect infrared polarizers

The analysis of vibrational bands is a core application of infrared (IR) spectroscopy. Polarization-dependent measurements enable the study of anisotropic materials. However, imperfect IR polarizers exhibit polarizer leakage, which causes pronounced bandshape and baseline distortions for samples with weak optical anisotropy. Based on the 4 × 4 Mueller-matrix formalism, we propose a polarimetric measurement scheme for handling imperfect polarizers and source prepolarization that delivers correct co- and crosspolarized transmission and reflection IR spectra. The scheme is applied to a weakly anisotropic polypropylene sheet, resolving crosspolarized signatures as small as 5⋅10−5. We determine the polymer's direction-dependent complex refractive index in the vibrational fingerprint range

An Amplitude Modulated Radio Telemetry System for the Measurement of Physiological Temperatures and a Revised Analysis of R-C Phase-shift Transistor Oscillators

In recent years, electronic instrumentation has been employed as a means of measuring physiological phenomena. One use of this instrumentation is the location of small radio transmitters within animals. The most common method of transmitting temperature data is by varying the carrier frequency of a small temperature sensitive oscillator located within the animal and recording the change of this frequency at the receiver; however, this system has some disadvantages. Reduction of these problems was believed to be possible by developing an amplitude modulated transmitting unit in which a temperature controlled audio oscillator would be used to amplitude modulate the carrier frequency oscillator. The variation in the audio frequency could then be recorded at the demodulated output of the received. This study is concerned with the investigation of two separate areas which are involved in a temperature telemetry system. One area is the use of electronic instruments to measure and transmit the temperature of unrestrained animals while the other area concerns the theory and application of the transistor R-C phase-shift oscillator as an important link in a certain type of temperature telemetry system. The audio oscillator selected was an R-C phase shift transistor oscillator with three R-C combinations in the feedback network. The temperature transducer consisted of two thermistors which were used as resistive elements in the feedback network. The carrier frequency was generated by a separate transistor Colpitts oscillator

Kundenbindungsstrategien für Charterfluggesellschaften : Kundenbindung jenseits von Bonusmeilen- und Vielfliegerprogrammen am Beispiel der TUIfly GmbH

Die Masterarbeit untersucht den Einfluss von Kundenloyalität auf mögliche Kundenbindungsstrategien für Charterfluggesellschaften am Beispiel der TUIfly GmbH. Aufgrund der herrschenden wettbewerbs-intensiven Bedingungen im europäischen Personenluftverkehr ist es für die Ferienfluggesellschaften immer bedeutender, den Kunden in den Mittelpunkt zu rücken und in seine Zufrieden-heit, Loyalität und Bindung zu investieren. Dies setzt jedoch ein umfassendes Wissen über den Kunden, seine Motive und Wünsche voraus. In diesem Zusammenhang wurde unter den TUIfly Kunden eine Online-Befragung durchgeführt, in der das Flugverhalten und die Motive für die Wahl der TUIfly GmbH als Fluggesellschaft erfasst wurden. Dabei konnten kundengruppen-spezifische Unterschiede festge-stellt werden, die sich sowohl auf die Loyalität, die Motive und die Nutzungs-häufigkeit der Kunden zurückführen lassen. Die gewonnenen Erkenntnisse werden abschließend in einer Handlungsempfehlung für die TUIfly GmbH zusammengefasst, um Aufschluss über Ansätze und Potentiale für mögliche Kundenbindungs-strategien zu geben. Im Fokus steht hierbei zu jeder Zeit die Beziehung zum Kunden als entscheidender Erfolgsfaktor eines Unternehmens

Spektroskopische Infrarotellipsometrie an funktionalen Polymerfilmen

Ziel der vorliegenden Arbeit ist die qualitative sowie quantitative Untersuchung funktionaler Polymerfilme und stimuli-responsiver Polymerbürsten mittels spektroskopischer Infrarotellipsometrie. Die Stärke dieser Messmethode ist in der Fähigkeit begründet, Molekülschwingungen organischer Dünnschichtsysteme an der Fest/Flüssig-Grenzfläche zu wässrigen Umgebungen in-situ zu vermessen und mittels optischer Schichtmodelle zu quantifizieren. Unter anderem geben diese Schwingungen Aufschluss über chemische Zusammensetzung, Struktur und Wechselwirkungen. Es ist somit erstmals möglich, verschiedene Polymer/Wasser- und Polymer/Polymer-Wechselwirkungen in temperatursensitiven Polymerfilmen und -bürsten ellipsometrisch zu identifizieren und erfolgreich, auf physikalischen Modellen basierend, zu quantifizieren. Des Weiteren wurde Infrarotellipsometrie bemüht, um Adsorptions- und Desorptionsprozesse von Proteinen an Polyelektrolytbürsten zu studieren. Komplementäre Messmethoden wie sichtbare Ellipsometrie und In-situ-Infrarotmikroskopie geben Aufschluss über zusätzliche Probeneigenschaften. Insbesondere erlauben es geometrische Überlegungen zum Streiflichtobjektiv erstmals, in-situ-infrarot-mikroskopische Messungen an Polymerdünnfilmen auf Metallen basierend auf denselben optischen Modellen auszuwerten, welche auch für Ellipsometrie genutzt werden. Dies gibt zusätzliche quantitative Einblicke in sich verändernde Wechselwirkungen bei Änderung der Umgebungsbedingungen, wie zum Beispiel Luftfeuchtigkeit.The aim of the present work is the qualitative as well as quantitative investigation of functional polymer films and stimuli-responsive polymer brushes by means of spectroscopic infrared ellipsometry. The strength of this method lies in its ability to measure molecular vibrations of organic thin-film systems in-situ at the solid–liquid interface to aqueous environments, and to quantify these vibrations with optical layer models. Among others, molecular vibrations give insights into chemical composition, structure, and interactions. For the first time, it was thus possible to ellipsometrically identify various polymer–water and polymer–polymer interactions in temperature-sensitive polymer films and brushes as well as to quantify these on the basis of physical models. Furthermore, infrared ellipsometry was employed for studying adsorption and desorption processes of proteins at polyelectrolyte brushes. Complementary methods like visible ellipsometry and in-situ infrared microscopy shed light on additional sample properties. In particular, geometric considerations with respect to the grazing-incidence objective allow one to evaluate in-situ infrared-microscopic measurements on polymer thin films on metal substrates based upon the same optical models as used for ellipsometry. This provides additional insights into changing interactions upon changes of environmental conditions like humidity

Probing carbonyl–water hydrogen-bond interactions in thin polyoxazoline brushes

Temperature-responsive oxazoline-based polymer brushes have gained increased attention as biocompatible surfaces. In aqueous environment, they can be tuned between hydrophilic and hydrophobic behavior triggered by a temperature stimulus. This transition is connected with changes in molecule–solvent interactions and results in a switching of the brushes between swollen and collapsed states. This work studies the temperature-dependent interactions between poly(2-oxazoline) brushes and water. In detail, thermoresponsive poly(2-cyclopropyl-2-oxazoline), nonresponsive hydrophilic poly(2-methyl-2-oxazoline), as well as a copolymer of the two were investigated with in situinfrared ellipsometry. Focus was put on interactions of the brushes’ carbonyl groups with water molecules. Different polymer–water interactions could be observed and assigned to hydrogen bonding between C=O groups and water molecules. The switching behavior of the brushes in the range of 20–45°C was identified by frequency shifts and intensity changes of the amide I band

Probing carbonyl–water hydrogen-bond interactions in thin polyoxazoline brushes

Temperature-responsive oxazoline-based polymer brushes have gained increased attention as biocompatible surfaces. In aqueous environment, they can be tuned between hydrophilic and hydrophobic behavior triggered by a temperature stimulus. This transition is connected with changes in molecule–solvent interactions and results in a switching of the brushes between swollen and collapsed states. This work studies the temperature-dependent interactions between poly(2-oxazoline) brushes and water. In detail, thermoresponsive poly(2-cyclopropyl-2-oxazoline), nonresponsive hydrophilic poly(2-methyl-2-oxazoline), as well as a copolymer of the two were investigated with in situinfrared ellipsometry. Focus was put on interactions of the brushes’ carbonyl groups with water molecules. Different polymer–water interactions could be observed and assigned to hydrogen bonding between C=O groups and water molecules. The switching behavior of the brushes in the range of 20–45°C was identified by frequency shifts and intensity changes of the amide I band

Probing carbonyl-water hydrogen-bond interactions in thin polyoxazoline brushes

Temperature-responsive oxazoline-based polymer brushes have gained increased attention as biocompatible surfaces. In aqueous environment, they can be tuned between hydrophilic and hydrophobic behavior triggered by a temperature stimulus. This transition is connected with changes in molecule–solvent interactions and results in a switching of the brushes between swollen and collapsed states. This work studies the temperature-dependent interactions between poly(2-oxazoline) brushes and water. In detail, thermoresponsive poly(2-cyclopropyl-2-oxazoline), nonresponsive hydrophilic poly(2-methyl-2-oxazoline), as well as a copolymer of the two were investigated with in situ infrared ellipsometry. Focus was put on interactions of the brushes' carbonyl groups with water molecules. Different polymer–water interactions could be observed and assigned to hydrogen bonding between C=O groups and water molecules. The switching behavior of the brushes in the range of 20–45 °C was identified by frequency shifts and intensity changes of the amide I band

Crosspolarization with imperfect infrared polarizers

The analysis of vibrational bands is a core application of infrared IR spectroscopy. Polarization dependent measurements enable the study of anisotropic materials. However, imperfect IR polarizers exhibit polarizer leakage, which causes pronounced bandshape and baseline distortions for samples with weak optical anisotropy. Based on the 4 4 Mueller matrix formalism, we propose a polarimetric measurement scheme for handling imperfect polarizers and source prepolarization that delivers correct co and crosspolarized transmission and reflection IR spectra. The scheme is applied to a weakly anisotropic polypropylene sheet, resolving crosspolarized signatures as small as . We determine the polymer s direction dependent complex refractive index in the vibrational fingerprint rang

Mid infrared laser ellipsometry a new era beyond FTIR

This view highlights a revolutionary change in IR ellipsometry, namely, the incorporation and application of tunable lasers. The presented instrumental developments beyond classical FTIR based approaches are coming precisely at the right time for today s demands for in situ, operando and hyperspectral characterization methods required in bioanalytics, catalysis and surface scienc