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>Magister Scientiae - MSc / Electron-mediated nuclear plasma interactions (NPIs), such as Nuclear Excitation by Electron Capture (NEEC) or Transition (NEET), can have a signi cant impact on nuclear cross sections in High Energy Density Plasmas (HEDPs). HEDP environments are found in nuclear weapons tests, National Ignition Facility (NIF) shots and in the cosmos where nucleosynthesis takes place. This thesis explores the impact of NPIs on highly excited nuclei. This impact is understood to be more intense in highly-excited nuclei states in the quasi-contiuum which is populated by nuclear reactions prior to their decay by spontaneous -ray emission. Attempts thus far have failed in measuring the NEEC process [1, 2], while NEET process has been observed experimentally [3, 4]. Direct observation of NPIs is hindered by the lack of a clear signature of their effect in HEDP environments. Hence this should test a new signature [5] for NPIs for highly-excited nuclei by investigating isomeric to ground state feeding from the isomeric state. An experiment was performed using the reactions 197Au(13C, 12C)198Au and 197Au(13C, 12C2n)196Au at Lawrence Berkeley National Laboratory in inverse kinematics with an 197Au beam of 8.5 MeV/u energy. Several measurements were performed with different target configurations. The activated foils were counted at the low-background counting facility of Lawrence Livermore National Laboratory. From these data, the double isomeric to ground state ratio (DIGS) were extracted with the assistance of the decay equations that were included in the experiment. As the NPIs effects are rather small the lines for analysis had to be chosen carefully so that the extracted ratios would not contain significant errors. The measured DIGS ratios were then compared with the result of the theoretical DIGS ratios. The results showed that the calculated DIGS ratios deviated substantially from unity although this was with large uncertainties. Because of the large errors obtained, the DIGS ratios were found to be inconclusive as a signature for detecting the effects of NPIs such as angular momentum distribution changes in HEDP environmen

<p>Studies of protein and peptide expression are vital in order to understand complex biological systems. As demonstrated in this thesis, on-line packed capillary liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR MS) is a useful analytical tool for such studies.</p><p>A proteomics method, based on global tryptic digestion and subsequent separation and detection of the peptides by LC-FTICR MS, was developed for qualitative analysis of body fluids. Initial experiments on cerebrospinal fluid (CSF) provided results that were comparable or superior to those achieved by more time- and sample-consuming techniques. The method was also successfully applied on plasma and amniotic fluid. One of the major challenges in proteomics is the broad dynamic range of proteins in biological matrices. The advantages of removing high-abundant components from CSF and plasma prior to MS were demonstrated.</p><p>In order to search for potential biomarkers, mass chromatograms of CSF from patients suffering from amyotrophic lateral sclerosis (ALS) and controls were compared using an in-house constructed pattern recognition program. ALS-specific patterns were observed, and four out of five unknown samples were correctly assigned. Alternative strategies to quantitatively compare two pools of samples rely on differential chemical labeling. The performance of one such method, quantification-using-enhanced-signal-tags, was investigated in complex sample analysis. The experimental intensity ratios were proven to be consistent with the prepared concentration ratios of abundant proteins in CSF.</p><p>Finally, the thesis reports on the first experiments where electron capture dissociation (ECD) was successfully incorporated in on-line LC-MS experiments. ECD and nozzle-skimmer fragmentation were applied to a sample of endocrine peptides extracted from mouse pancreatic islets. The two fragmentation methods provided complementary information. However, the method needs further optimization before it can be applied in the analysis of more complex samples, such as body fluids.</p>

Studies of protein and peptide expression are vital in order to understand complex biological systems. As demonstrated in this thesis, on-line packed capillary liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR MS) is a useful analytical tool for such studies. A proteomics method, based on global tryptic digestion and subsequent separation and detection of the peptides by LC-FTICR MS, was developed for qualitative analysis of body fluids. Initial experiments on cerebrospinal fluid (CSF) provided results that were comparable or superior to those achieved by more time- and sample-consuming techniques. The method was also successfully applied on plasma and amniotic fluid. One of the major challenges in proteomics is the broad dynamic range of proteins in biological matrices. The advantages of removing high-abundant components from CSF and plasma prior to MS were demonstrated. In order to search for potential biomarkers, mass chromatograms of CSF from patients suffering from amyotrophic lateral sclerosis (ALS) and controls were compared using an in-house constructed pattern recognition program. ALS-specific patterns were observed, and four out of five unknown samples were correctly assigned. Alternative strategies to quantitatively compare two pools of samples rely on differential chemical labeling. The performance of one such method, quantification-using-enhanced-signal-tags, was investigated in complex sample analysis. The experimental intensity ratios were proven to be consistent with the prepared concentration ratios of abundant proteins in CSF. Finally, the thesis reports on the first experiments where electron capture dissociation (ECD) was successfully incorporated in on-line LC-MS experiments. ECD and nozzle-skimmer fragmentation were applied to a sample of endocrine peptides extracted from mouse pancreatic islets. The two fragmentation methods provided complementary information. However, the method needs further optimization before it can be applied in the analysis of more complex samples, such as body fluids.

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Mass spectrometry has in recent years been established as the standard method for protein identification and characterization in proteomics with excellent intrinsic sensitivity and specificity. Fourier transform ion cyclotron resonance is the mass spectrometric technique that provides the highest resolving power and mass accuracy, increasing the amount of information that can be obtained from complex samples. This thesis concerns how useful information on proteins of interest can be extracted from mass spectrometric data on different levels of protein structure and how to obtain this data experimentally. It was shown that it is possible to analyze complex mixtures of protein tryptic digests by direct infusion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry and identify abundant proteins by peptide mass fingerprinting. Coupling on-line methods such as liquid chromatography and capillary electrophoresis increased the number of proteins that could be identified in human body fluids. Protein identification was also improved by novel statistical methods utilizing prediction of chromatographic behavior and the non-randomness of enzymatic digestion. To identify proteins by short sequence tags, electron capture dissociation was implemented, improved and finally coupled on-line to liquid chromatography for the first time. The combined techniques can be used to sequence large proteins de novo or to localize and characterize any labile post-translational modification. New computer algorithms for the automated analysis of isotope exchange mass spectra were developed to facilitate the study of protein structural dynamics. The non-covalent interaction between HIV-inhibitory peptides and the oligomerization of amyloid β-peptides were investigated, reporting several new findings with possible relevance for development of anti-HIV drug therapies and understanding of fundamental mechanisms in Alzheimer’s disease.

In the presented PhD. thesis, problems covering occurrence of polybrominated diphenyl ethers (PBDE) and perfluorinated compounds in the environment were solved. The study was focused on identification and further verification of optimal methods in order to determine PBDEs and perfluorinated compounds sampled from the aquatic ecosystem. Polybrominated diphenyl ethers belong to persistent compounds classified as main pollutants; within the environmental constituents, they have been observed particularly in the last decade. For these studies, there were selected surface water matrices and sediments taken in various localities within the river Svratka basin. The analyses were to demonstrate whether they accumulate and remain in these specific matrices for longer time. There we assessed the congeners of polybrominated diphenyl ethers as follows: BDE-28, 47, 66, 85, 99, 100, 153, 154 and 183. In order to isolate them from matrices, various extraction techniques were used, i.e., ultrasonic extraction, microwave extraction, and pressure solvent extraction. Gas chromatography method with electron capture detection (GC/ECD) was selected for determination. The accomplished studies also assessed basic chemical, physical and environmental characteristics of diphenyl ethers in the environmental constituents. The attention was also paid to perfluorooctanoic compounds (PFOA), (PFOS) and (FOSA); physico-chemical properties of these organic pollutants were characterised and their toxicological and environmental aspects were evaluated. Usability of extraction techniques (ultrasonic extraction, pressure solvent extraction, solid phase extraction) applied to PFCs isolation from sediments samples was assessed. Identification and quantification of these analytes were performed using a high performance liquid chromatography/mass spectrometry method (HPLC/MS). After that, the optimized methods applied to real samples. Surface water and sediments were sampled within the river Svratka basin, in particular, from 19 sampling localities. PBDE occurrence was confirmed in sediments samples from the Svratka river (g.kg-1), PBDE were not detected in the surface water samples, their concentrations were below the detection limit, resp.; perfluorinated compounds were not detected in sediments and water samples at all.

Ein Ziel der modernen Physik ist die experimentelle Beobachtung des neutrinolosen Doppelbetazerfalls (0nbb). Unter den wenigen in der Natur vorkommenden Nukliden ist 76-Ge ein möglicher Kandidat an denen dieser Prozess unter anderem mit dem Experiment GERDA nachgewiesen werden soll. Die extrem geringe Wahrscheinlichkeit für das Auftreten einer 0nbb-Umwandlung ist mindestens zehn Größenordnungen kleiner ist als die des Beta-Zerfalls von 115-In mit einer Halbwertszeit von 4,41x10^14 Jahren, einem der seltensten in der Natur beobachteten Kernumwandlungen. Die dafür erforderliche hohe Detektions Sensitivität wird unter anderem vom Messuntergrund bestimmt, dessen genaue Kenntnis für die Auswertung der Messdaten erforderlich ist. In dieser Arbeit wurden neutronenphysikalische Studien an Germanium durchgeführt, die essentielle Lücken in diesem Kenntnisstand schließen. Neutronen können durch direkte Wechselwirkung mit Germanium sowie der umgebenden Materie des Detektors oder indirekt durch Aktivierung Zählereignisse hervorrufen. Für das Verständnis des damit verursachten Untergrundes wurde der Neutronenwechselwirkungsquerschnitt 70-Ge(n,3n)68-Ge, das Anregungsschema von 76-Ge und der energieabhängige Anregungsquerschnitt für einige dieser Zustände untersucht. Der mangelhafte Messdatenbestand für natürlich vorkommende Germaniumisotope wird dabei entscheidend verbessert. Um die Untersuchung des 76-Ge Anregungsschemas und den Zugang zu einer Palette weiterer Experimente zu ermöglichen, wurde im Rahmen dieser Arbeit ein leistungsfähiges, sehr speziellen Anforderungen entsprechendes Rohrpostsystem entwickelt und im Neutronenlabor der TU Dresden installiert. Ein weiteres neutronenphysikalisches Experiment untersucht den bisher unbeobachteten Elektroneneinfang von 76-As. Dadurch wird eine Möglichkeit gezeigt die oftmals nur mit theoretischen Modellen zugänglichen und mit großen Unsicherheiten behafteten Übergansmatrixelemente experimentell zu bestimmen. Diese spielen bei der Auswertung von Experimenten zum Doppelbetazerfall, insbesondere des Experimentes GERDA, eine entscheidende Rolle. / One goal of modern physics is the experimental observation of the neutrinoless double beta decay (0nbb). Among the few naturally occurring nuclides 76-Ge is one candidate to which this process is to verify, amongest others with the GERDA experiment. The extremely low probability of occurrence for a 0nbb-decay is of at least ten orders of magnitude smaller than that of the Beta-decay of 115-In, one of the rarest beta transitions observed in nature with a half-life of 4.41x10^14 years. Thefore a high detection sensitivity is required, wich depends among other things on the measuring background. Its exact knowledge is necessary for the evaluation of the measuring data. In this work neutron-physical studies were performed on germanium aiming to close the essential gaps in this state of knowledge. Neutrons can cause counting events by direct interaction with germanium and the surrounding matter of the detector or indirectly by activation of any of these materials. For understanding of those background signals, the neutron interaction cross section 70-Ge(n,3n)68-Ge, the levelsceme and the energy-dependent excitation cross section of 76-Ge has been investigated. The lack of data inventory for natural germanium has been improved significantly. To enable the investigation of the 76-Ge level sceme and the access to a range of other experiments, a powerful, very special requirements corresponding pneumatic tube system was developed and installed in scope of this work at the neutron laboratory of the TU Dresden. Another neutron physics experiment examined the so far unobserved electroncapture of 76-As. This shows one way to determine transition matrix elements experimentally, which is often only accessible through theoretical models and prone to large uncertainties. These Matrix elements play a crucial role in the analysis of experiments on double beta decay, in particular the GERDA experiment.

Ein Ziel der modernen Physik ist die experimentelle Beobachtung des neutrinolosen Doppelbetazerfalls (0nbb). Unter den wenigen in der Natur vorkommenden Nukliden ist 76-Ge ein möglicher Kandidat an denen dieser Prozess unter anderem mit dem Experiment GERDA nachgewiesen werden soll. Die extrem geringe Wahrscheinlichkeit für das Auftreten einer 0nbb-Umwandlung ist mindestens zehn Größenordnungen kleiner ist als die des Beta-Zerfalls von 115-In mit einer Halbwertszeit von 4,41x10^14 Jahren, einem der seltensten in der Natur beobachteten Kernumwandlungen. Die dafür erforderliche hohe Detektions Sensitivität wird unter anderem vom Messuntergrund bestimmt, dessen genaue Kenntnis für die Auswertung der Messdaten erforderlich ist. In dieser Arbeit wurden neutronenphysikalische Studien an Germanium durchgeführt, die essentielle Lücken in diesem Kenntnisstand schließen. Neutronen können durch direkte Wechselwirkung mit Germanium sowie der umgebenden Materie des Detektors oder indirekt durch Aktivierung Zählereignisse hervorrufen. Für das Verständnis des damit verursachten Untergrundes wurde der Neutronenwechselwirkungsquerschnitt 70-Ge(n,3n)68-Ge, das Anregungsschema von 76-Ge und der energieabhängige Anregungsquerschnitt für einige dieser Zustände untersucht. Der mangelhafte Messdatenbestand für natürlich vorkommende Germaniumisotope wird dabei entscheidend verbessert. Um die Untersuchung des 76-Ge Anregungsschemas und den Zugang zu einer Palette weiterer Experimente zu ermöglichen, wurde im Rahmen dieser Arbeit ein leistungsfähiges, sehr speziellen Anforderungen entsprechendes Rohrpostsystem entwickelt und im Neutronenlabor der TU Dresden installiert. Ein weiteres neutronenphysikalisches Experiment untersucht den bisher unbeobachteten Elektroneneinfang von 76-As. Dadurch wird eine Möglichkeit gezeigt die oftmals nur mit theoretischen Modellen zugänglichen und mit großen Unsicherheiten behafteten Übergansmatrixelemente experimentell zu bestimmen. Diese spielen bei der Auswertung von Experimenten zum Doppelbetazerfall, insbesondere des Experimentes GERDA, eine entscheidende Rolle. / One goal of modern physics is the experimental observation of the neutrinoless double beta decay (0nbb). Among the few naturally occurring nuclides 76-Ge is one candidate to which this process is to verify, amongest others with the GERDA experiment. The extremely low probability of occurrence for a 0nbb-decay is of at least ten orders of magnitude smaller than that of the Beta-decay of 115-In, one of the rarest beta transitions observed in nature with a half-life of 4.41x10^14 years. Thefore a high detection sensitivity is required, wich depends among other things on the measuring background. Its exact knowledge is necessary for the evaluation of the measuring data. In this work neutron-physical studies were performed on germanium aiming to close the essential gaps in this state of knowledge. Neutrons can cause counting events by direct interaction with germanium and the surrounding matter of the detector or indirectly by activation of any of these materials. For understanding of those background signals, the neutron interaction cross section 70-Ge(n,3n)68-Ge, the levelsceme and the energy-dependent excitation cross section of 76-Ge has been investigated. The lack of data inventory for natural germanium has been improved significantly. To enable the investigation of the 76-Ge level sceme and the access to a range of other experiments, a powerful, very special requirements corresponding pneumatic tube system was developed and installed in scope of this work at the neutron laboratory of the TU Dresden. Another neutron physics experiment examined the so far unobserved electroncapture of 76-As. This shows one way to determine transition matrix elements experimentally, which is often only accessible through theoretical models and prone to large uncertainties. These Matrix elements play a crucial role in the analysis of experiments on double beta decay, in particular the GERDA experiment.