Das Verhalten und die Struktur der Atome werden durch die Elektronenhülle bestimmt. Die Atome kön... more Das Verhalten und die Struktur der Atome werden durch die Elektronenhülle bestimmt. Die Atome können nur verstanden und berechnet werden, wenn man den Teilchen-und Wellencharakter der Elektronen berücksichtigt. Das Wasserstoffatom kann so relativ einfach berechnet werden und man erhält numerisch die Energien der einzelnen Zustände, sowie die Wellenlängen der Spektrallinien. Jeder Zustand wird durch 4 Quantenzahlen beschrieben, mit denen auch der Aufbau des Periodensystems verstanden werden kann. Es werden wichtige Anwendungen der Atomphysik beschrieben, wie die Röntgenröhre und deren Strahlung, die Spin-und Kernspinresonanz, die Computertomographie (CT und MRT) und die Synchrotronstrahlung. Weiterhin wird auf die Energiezustände von Molekülen und entsprechende Anwendungen hingewiesen.
Die Physik, vom griechischen "physis D Natur" stammend, beschäftigt sich mit der Erforschung und ... more Die Physik, vom griechischen "physis D Natur" stammend, beschäftigt sich mit der Erforschung und dem Verstehen der unbelebten Natur. Sie bildet ein unentbehrliches Fundament für andere Naturwissenschaften, wie die Chemie und die Biologie. Es ist ein Ziel der Physik, die Vielfalt der Erscheinungen einheitlich durch Naturgesetze zu beschreiben. Die Naturvorgänge werden gezielt durch Experimente studiert und nach einer gedanklichen Durchdringung in der Sprache der Mathematik formuliert. Die Aussagen und Ergebnisse einer physikalischen Beschreibung sollen in messbaren, zahlenmäßig erfassbaren Werten gemacht werden. Die moderne Technik ist ohne die Physik nicht denk-und verstehbar, die Naturwissenschaft von heute ist die Grundlage der Technik von morgen. Beispiele dafür sind die Mikroelektronik, die Lasertechnik und die sich stürmisch entwickelnde Photonik. Bedauerlicherweise zählen dazu auch einige 10.000 Atombomben und andere Waffensysteme. Die Frage, ob die Auswirkungen der Physik zum Wohl der Menschheit dienen, bleibt damit gegenwärtig noch unbeantwortet-es hängt von uns ab. 1.1 Basisgrößen und-einheiten 1.1.1 SI-System 1.1.1.1 Zahlenwert und Einheit Zur Formulierung von Zusammenhängen und Gesetzen werden mathematische Gleichungen aufgestellt. In diesen erscheinen physikalische Größen G, die in der Regel messbar sind. Sie bestehen aus einem Zahlenwert {G} und der Einheit [G]:
Turbidity sensing is very common in the control of drinking water. Furthermore, turbidity measure... more Turbidity sensing is very common in the control of drinking water. Furthermore, turbidity measurements are applied in the chemical (e.g., process monitoring), pharmaceutical (e.g., drug discovery), and food industries (e.g., the filtration of wine and beer). The most common measurement technique is nephelometric turbidimetry. A nephelometer is a device for measuring the amount of scattered light of suspended particles in a liquid by using a light source and a light detector orientated in 90 • to each other. Commercially available nephelometers cost usually-depending on the measurable range, reliability, and precision-thousands of euros. In contrast, our new developed GRIN-lens-based nephelometer, called GRINephy, combines low costs with excellent reproducibility and precision, even at very low turbidity levels, which is achieved by its ability to rotate the sample. Thereby, many cuvette positions can be measured, which results in a more precise average value for the turbidity calculated by an algorithm, which also eliminates errors caused by scratches and contaminations on the cuvettes. With our compact and cheap Arduino-based sensor, we are able to measure in the range of 0.1-1000 NTU and confirm the ISO 7027-1:2016 for low turbidity values.
... Page 7. where k is Boltzmann's constant, T is the temperature in K, and h is the solvent... more ... Page 7. where k is Boltzmann's constant, T is the temperature in K, and h is the solvent viscosity. gð1ÞðtÞ for a polydisperse solution containing L different macromolecular species (or aggregates) with masses Mi, diffusion coefficients Di and weight con-centrations ci is ...
Masse des Elektrons me , ⋅ − kg Masse des Protons mp ,l ⋅ − kg Masse des Ne... more Masse des Elektrons me , ⋅ − kg Masse des Protons mp ,l ⋅ − kg Masse des Neutrons mn , ⋅ − kg Atommassenkonstante m( C)/12 mu , ⋅ − kg
We have investigated the conformational transition and aggregation process of recombinant Syrian ... more We have investigated the conformational transition and aggregation process of recombinant Syrian hamster prion protein (SHaPrP 90-232) by Fourier transform infrared spectroscopy, circular dichroism spectroscopy, light scattering, and electron microscopy under equilibrium and kinetic conditions. SHaPrP 90-232 showed an infrared absorbance spectrum typical of proteins with a predominant ␣-helical structure both at pH 7.0 and at pH 4.2 in the absence of guanidine hydrochloride. At pH 4.2 and destabilizing conditions (0.3-2 M guanidine hydrochloride), the secondary structure of SHaPrP 90-232 was transformed to a strongly hydrogen-bonded, most probably intermolecularly arranged antiparallel -sheet structure as indicated by dominant amide I band components at 1620 and 1691 cm ؊1. Kinetic analysis of the transition process showed that the decrease in ␣-helical structures and the increase in -sheet structures occurred concomitantly according to a bimolecular reaction. However, the concentration dependence of the corresponding rate constant pointed to an apparent third order reaction. No -sheet structure was formed within the dead time (190 ms) of the infrared experiments. Light scattering measurements revealed that the structural transition of SHaPrP 90-232 was accompanied by formation of oligomers, whose size was linearly dependent on protein concentration. Extrapolation to zero protein concentration yielded octamers as the smallest oligomers, which are considered as "critical oligomers." The small oligomers showed spherical and annular shapes in electron micrographs. Critical oligomers seem to play a key role during the transition and aggregation process of SHaPrP 90-232. A new model for the structural transition and aggregation process of the prion protein is described.
Amyloid protofibril formation of phosphoglycerate kinase (PGK) and Syrian hamster prion protein (... more Amyloid protofibril formation of phosphoglycerate kinase (PGK) and Syrian hamster prion protein (SHaPrP(90-232)) were investigated by static and dynamic light scattering, size exclusion chromatography and electron microscopy. Changes in secondary structure were monitored by Fourier transform infrared spectroscopy and by circular dichroism. Protofibril formation of the two proteins is found to be a two-stage process. At the beginning, an ensemble of critical oligomers is built up. These critical oligomeric states possess a predominant beta-sheet structure and do not interact considerably with monomers. Initial oligomerization and transition to beta-sheet structure are coupled events differing in their details for both proteins. Intermediate oligomeric states (dimers, trimers, etc.) are populated in case of PGK, whereas SHaPrP(90-232) behaves according to an apparent two-state reaction between monomers and octamers rich in beta-structure with a reaction order varying between 2 and 4. All oligomers coalesce to PGK protofibrils in the second stage, while SHaPrP(90-232) protofibrils are only formed by a subpopulation. The rates of both growth stages can be tuned in case of PGK by different salts preserving the underlying generalized diffusion-collision mechanism. The different kinetics of the early misfolding and oligomerization events of the two proteins argue against a common mechanism of protofibril formation. A classification scheme for misassembly mechanisms of proteins based on energy landscapes is presented. It includes scenarios of downhill polymerization to which protofibril formation of PGK and SHaPrP(90-232) belong.
The dependence on environmental conditions of the assembly of barstar into amyloid fibrils was in... more The dependence on environmental conditions of the assembly of barstar into amyloid fibrils was investigated starting from the nonnative, partially folded state at low pH (A-state). The kinetics of this process was monitored by CD spectroscopy and static and dynamic light scattering. The morphology of the fibrils was visualized by electron microscopy, while the existence of the typical cross-beta structure substantiated by solution X-ray scattering. At room temperature, barstar in the A-state is unable to form amyloid fibrils, instead amorphous aggregation is observed at high ionic strength. Further destabilization of the structure is required to transform the polypeptide chain into an ensemble of conformations capable of forming amyloid fibrils. At moderate ionic strength (75 mM NaCl), the onset and the rate of fibril formation can be sensitively tuned by increasing the temperature. Two types of fibrils can be detected differing in their morphology, length distribution and character...
Das Verhalten und die Struktur der Atome werden durch die Elektronenhülle bestimmt. Die Atome kön... more Das Verhalten und die Struktur der Atome werden durch die Elektronenhülle bestimmt. Die Atome können nur verstanden und berechnet werden, wenn man den Teilchen-und Wellencharakter der Elektronen berücksichtigt. Das Wasserstoffatom kann so relativ einfach berechnet werden und man erhält numerisch die Energien der einzelnen Zustände, sowie die Wellenlängen der Spektrallinien. Jeder Zustand wird durch 4 Quantenzahlen beschrieben, mit denen auch der Aufbau des Periodensystems verstanden werden kann. Es werden wichtige Anwendungen der Atomphysik beschrieben, wie die Röntgenröhre und deren Strahlung, die Spin-und Kernspinresonanz, die Computertomographie (CT und MRT) und die Synchrotronstrahlung. Weiterhin wird auf die Energiezustände von Molekülen und entsprechende Anwendungen hingewiesen.
Die Physik, vom griechischen "physis D Natur" stammend, beschäftigt sich mit der Erforschung und ... more Die Physik, vom griechischen "physis D Natur" stammend, beschäftigt sich mit der Erforschung und dem Verstehen der unbelebten Natur. Sie bildet ein unentbehrliches Fundament für andere Naturwissenschaften, wie die Chemie und die Biologie. Es ist ein Ziel der Physik, die Vielfalt der Erscheinungen einheitlich durch Naturgesetze zu beschreiben. Die Naturvorgänge werden gezielt durch Experimente studiert und nach einer gedanklichen Durchdringung in der Sprache der Mathematik formuliert. Die Aussagen und Ergebnisse einer physikalischen Beschreibung sollen in messbaren, zahlenmäßig erfassbaren Werten gemacht werden. Die moderne Technik ist ohne die Physik nicht denk-und verstehbar, die Naturwissenschaft von heute ist die Grundlage der Technik von morgen. Beispiele dafür sind die Mikroelektronik, die Lasertechnik und die sich stürmisch entwickelnde Photonik. Bedauerlicherweise zählen dazu auch einige 10.000 Atombomben und andere Waffensysteme. Die Frage, ob die Auswirkungen der Physik zum Wohl der Menschheit dienen, bleibt damit gegenwärtig noch unbeantwortet-es hängt von uns ab. 1.1 Basisgrößen und-einheiten 1.1.1 SI-System 1.1.1.1 Zahlenwert und Einheit Zur Formulierung von Zusammenhängen und Gesetzen werden mathematische Gleichungen aufgestellt. In diesen erscheinen physikalische Größen G, die in der Regel messbar sind. Sie bestehen aus einem Zahlenwert {G} und der Einheit [G]:
Turbidity sensing is very common in the control of drinking water. Furthermore, turbidity measure... more Turbidity sensing is very common in the control of drinking water. Furthermore, turbidity measurements are applied in the chemical (e.g., process monitoring), pharmaceutical (e.g., drug discovery), and food industries (e.g., the filtration of wine and beer). The most common measurement technique is nephelometric turbidimetry. A nephelometer is a device for measuring the amount of scattered light of suspended particles in a liquid by using a light source and a light detector orientated in 90 • to each other. Commercially available nephelometers cost usually-depending on the measurable range, reliability, and precision-thousands of euros. In contrast, our new developed GRIN-lens-based nephelometer, called GRINephy, combines low costs with excellent reproducibility and precision, even at very low turbidity levels, which is achieved by its ability to rotate the sample. Thereby, many cuvette positions can be measured, which results in a more precise average value for the turbidity calculated by an algorithm, which also eliminates errors caused by scratches and contaminations on the cuvettes. With our compact and cheap Arduino-based sensor, we are able to measure in the range of 0.1-1000 NTU and confirm the ISO 7027-1:2016 for low turbidity values.
... Page 7. where k is Boltzmann's constant, T is the temperature in K, and h is the solvent... more ... Page 7. where k is Boltzmann's constant, T is the temperature in K, and h is the solvent viscosity. gð1ÞðtÞ for a polydisperse solution containing L different macromolecular species (or aggregates) with masses Mi, diffusion coefficients Di and weight con-centrations ci is ...
Masse des Elektrons me , ⋅ − kg Masse des Protons mp ,l ⋅ − kg Masse des Ne... more Masse des Elektrons me , ⋅ − kg Masse des Protons mp ,l ⋅ − kg Masse des Neutrons mn , ⋅ − kg Atommassenkonstante m( C)/12 mu , ⋅ − kg
We have investigated the conformational transition and aggregation process of recombinant Syrian ... more We have investigated the conformational transition and aggregation process of recombinant Syrian hamster prion protein (SHaPrP 90-232) by Fourier transform infrared spectroscopy, circular dichroism spectroscopy, light scattering, and electron microscopy under equilibrium and kinetic conditions. SHaPrP 90-232 showed an infrared absorbance spectrum typical of proteins with a predominant ␣-helical structure both at pH 7.0 and at pH 4.2 in the absence of guanidine hydrochloride. At pH 4.2 and destabilizing conditions (0.3-2 M guanidine hydrochloride), the secondary structure of SHaPrP 90-232 was transformed to a strongly hydrogen-bonded, most probably intermolecularly arranged antiparallel -sheet structure as indicated by dominant amide I band components at 1620 and 1691 cm ؊1. Kinetic analysis of the transition process showed that the decrease in ␣-helical structures and the increase in -sheet structures occurred concomitantly according to a bimolecular reaction. However, the concentration dependence of the corresponding rate constant pointed to an apparent third order reaction. No -sheet structure was formed within the dead time (190 ms) of the infrared experiments. Light scattering measurements revealed that the structural transition of SHaPrP 90-232 was accompanied by formation of oligomers, whose size was linearly dependent on protein concentration. Extrapolation to zero protein concentration yielded octamers as the smallest oligomers, which are considered as "critical oligomers." The small oligomers showed spherical and annular shapes in electron micrographs. Critical oligomers seem to play a key role during the transition and aggregation process of SHaPrP 90-232. A new model for the structural transition and aggregation process of the prion protein is described.
Amyloid protofibril formation of phosphoglycerate kinase (PGK) and Syrian hamster prion protein (... more Amyloid protofibril formation of phosphoglycerate kinase (PGK) and Syrian hamster prion protein (SHaPrP(90-232)) were investigated by static and dynamic light scattering, size exclusion chromatography and electron microscopy. Changes in secondary structure were monitored by Fourier transform infrared spectroscopy and by circular dichroism. Protofibril formation of the two proteins is found to be a two-stage process. At the beginning, an ensemble of critical oligomers is built up. These critical oligomeric states possess a predominant beta-sheet structure and do not interact considerably with monomers. Initial oligomerization and transition to beta-sheet structure are coupled events differing in their details for both proteins. Intermediate oligomeric states (dimers, trimers, etc.) are populated in case of PGK, whereas SHaPrP(90-232) behaves according to an apparent two-state reaction between monomers and octamers rich in beta-structure with a reaction order varying between 2 and 4. All oligomers coalesce to PGK protofibrils in the second stage, while SHaPrP(90-232) protofibrils are only formed by a subpopulation. The rates of both growth stages can be tuned in case of PGK by different salts preserving the underlying generalized diffusion-collision mechanism. The different kinetics of the early misfolding and oligomerization events of the two proteins argue against a common mechanism of protofibril formation. A classification scheme for misassembly mechanisms of proteins based on energy landscapes is presented. It includes scenarios of downhill polymerization to which protofibril formation of PGK and SHaPrP(90-232) belong.
The dependence on environmental conditions of the assembly of barstar into amyloid fibrils was in... more The dependence on environmental conditions of the assembly of barstar into amyloid fibrils was investigated starting from the nonnative, partially folded state at low pH (A-state). The kinetics of this process was monitored by CD spectroscopy and static and dynamic light scattering. The morphology of the fibrils was visualized by electron microscopy, while the existence of the typical cross-beta structure substantiated by solution X-ray scattering. At room temperature, barstar in the A-state is unable to form amyloid fibrils, instead amorphous aggregation is observed at high ionic strength. Further destabilization of the structure is required to transform the polypeptide chain into an ensemble of conformations capable of forming amyloid fibrils. At moderate ionic strength (75 mM NaCl), the onset and the rate of fibril formation can be sensitively tuned by increasing the temperature. Two types of fibrils can be detected differing in their morphology, length distribution and character...
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Papers by Andreas Modler