Datenbank- und Netzwerkprogrammierung in Java

Die Diplomarbeit befasst sich im zweiten Kapitel mir Datenbanken. Es werden die Anforderungen an Datenbanken formuliert. Des weiteren wird in diesem Kapitel auf dea ER-Modell und auf SQL eingegangen. Im nächsten Kapitel werden die Methoden und die Datentypen von Java vorgestellt. Im vierten Kapitel wird anhand eines Beispieles eine JDBC-Anwedung erläutert. Das fünfte Kapitel handelt von der Systemarchitektur in RMI. In einem Beispiel wird eine RMI-Anwendung abgehandelt

Elektronische Relaxationsprozesse Inner-Valenz-ionisierter Moleküle und Cluster

In der vorliegenden Arbeit wurden elektronische Relaxationsprozesse Valenz-ionisierter Moleküle und Cluster mittels quantenchemischer ab-initio Verfahren untersucht. Als zentrales Resultat dieser Studien konnte ein neuartiger elektronischer Relaxationsprozess für die Inner-Valenz-ionisierten Zustände schwach gebundener Cluster aufgezeigt und analysiert werden. Während die Valenz-ionisierten Zustände isolierter atomarer und kleiner molekularer Systeme (Monomere) aus energetischen Gründen nur im Rahmen relativ langsamer Photonemissions- bzw. Kerndynamik-Prozesse relaxieren können, eröffnet die "Einbettung" dieser Monomere in einen schwach gebundenen Cluster einen äußerst effizienten elektronischen Zerfallsprozess der Inner-Valenz-ionisierten Zustände. Das Ergebnis der Analyse des Zerfallsmechanismus läßt sich in einem vereinfachten schematischen Bild darstellen: Ein Inner-Valenz-ionisierter Ausgangszustand mit lokalisierter Lochladung an einem der schwach gebundenen Clustermonomere zerfällt, indem ein Elektron aus der äußeren Valenz des selben Monomers das ursprüngliche Inner-Valenz-Loch "auffüllt". Die dabei freigesetzte Überschussenergie wird im Rahmen eines effizienten interatomaren bzw. intermolekularen Kopplungsmechanismus zu einem Nachbarmonomer transferiert. Dort führt die Überschussenergie zur Emission eines Elektrons aus der äußeren Valenz. Der resultierende doppelionisierte Zerfallskanal besitzt jeweils eine lokalisierte Lochladung an den beiden benachbarten Monomereinheiten. Die reduzierte Coulomb-Abstoßung der räumlich verteilten Lochladungen führt zu einer drastischen energetischen Absenkung der Doppelionisierungsschwelle gegenüber der Lage in den isolierten Monomereinheiten, und somit zur Öffnung der Zerfallskanäle für die Inner--Valenz--ionisierten Clusterzustände. Der interatomare bzw. intermolekulare Mechanismus des elektronischen Zerfalls der Inner--Valenz--ionisierten Clusterzustände steht in deutlichem Gegensatz zur ausgeprägt intraatomaren Natur des elektronischen Zerfalls elektronisch hochangeregter, Core-ionisierter Zustände (Auger-Zerfall). Auf Grund der dominierenden Coulomb-Wechselwirkung zwischen den Elektronen der am Zerfallsprozess beteiligten Nachbarmonomere wurde der elektronische Zerfall Inner-Valenz-ionisierter Clusterzustände als Interatomic bzw. Intermolecular Coulombic Decay (ICD) bezeichnet. Die große Effizienz des ICD-Prozesses spiegelt sich in den berechneten kurzen Lebensdauern der zerfallenden Inner-Valenz-ionisierten Ausgangszustände im Größenbereich von ca. 1-100 Femtosekunden wieder. Die enorme Bedeutung des ICD-Prozesses für schwach gebundene Systeme zeigt sich im Rahmen der exemplarischen Analyse H-verbrückter Molekülcluster (z.B. H2O- und HF-Cluster) und van-der-Waals-Cluster (Neon-Cluster). Im Detail untersucht wurde unter anderem die Größen- und Abstandsabhängigkeit des elektronischen Zerfallsprozesses. Am Beispiel der heterogenen NeAr- und NeCO-Systeme konnte eine für kurze Monomerabstände relevante Elektrontransfer-vermittelte Variante des ICD-Prozesses aufgezeigt und analysiert werden. Für doppelionisierte Clusterzustände mit mindestens einem Inner-Valenz-Loch wurde das Auftreten eines ICD-analogen elektronischen Zerfallsprozesses vorhergesagt. Die mit der Betrachtung schwach gebundener Cluster begonnenen ab-initio Studien der elektronischen Relaxationsprozesse Valenz-ionisierter Zustände wurden auf molekulare Systeme ausgeweitet. Für Inner-Valenz-ionisierte Zustände "ausgedehnter" molekularer Systeme, sowie kleiner molekularer Anionen konnte eine intramolekulare Variante des ICD-Prozesses aufgezeigt werden. Darüber hinaus wurde die Möglichkeit eines ultraschnellen rein elektronischen Loch-Ladungstransferprozesses für nicht-stationäre Valenz-ionisierte Ausgangszustände molekularer Systeme nachgewiesen. Der im Rahmen der vorliegenden Arbeit erstmals postulierte ICD-Prozess konnte mittlerweile im Rahmen von Photoionisierungsstudien an Neon- und gemischten Neon/Argon-Clustern experimentell nachgewiesen werden. Die Ergebnisse dieser experimentellen Untersuchungen bestätigen die theoretischen Vorhersagen der hier vorgelegten ab-initio Studien

Giant intermolecular decay and fragmentation of clusters. Phys

In sharp contrast to molecules, electronic states of clusters with an excited intermediate-shell electron can efficiently decay via an intermolecular Coulombic mechanism. Explicit examples are presented using large scale ab initio propagator calculations. The mechanism is illustrated and its generality is stressed. [S0031-9007(97) PACS numbers: 36.40. Cg, 31.50. + w, 34.50.Gb Quantum states of electronic systems typically decay by photon and/or electron emission. Energetically low lying states decay radiatively while highly excited levels involving the excitation of inner-shell electrons decay more efficiently by emitting an electron (Auger decay). It is only for very deep inner-shell electrons of heavy elements that x-ray emission constitutes the prominent decay channel As mentioned above, the environment of the atom influences only moderately the lifetime of the deep vacancy (e.g., of a F1s vacancy). If at all, we can only expect interesting environmental effects on the total Auger decay rate to take place for vacancies in intermediate shells. However, a closer look at the energetics of the decay in typical molecules brings a problem to light. The ionization potential (IP) of a F2s electron in, say, the HF molecule, is about 40 eV Atomic and molecular clusters have been subject to continuous interest over many years We propose to use a different approach. The groups involved in the present study have acquired considerable experience in the ab initio computation of ionization The ionization and Auger spectra of several monomers and clusters have been computed using the methods described in Refs

Anesthetic management in patients suspected of Creutzfeldt-Jakob disease -A case report-

Creutzfeldt-Jakob disease (CJD) is a fatal neurodegenerative disorder in which accumulation of the pathogenic prion protein induces neuronal damage and results in distinct pathologic features. This abnormal prion is an infectious protein and resistant to methods of sterilization currently being used. Therefore, management of definite, or suspected CJD patients requires additional precautions. We report our experience of a patient who had undergone brain biopsy for suspected of CJD. The patient was confirmed to have sporadic CJD

A standardized comparison of commercially available prion decontamination reagents using the Standard Steel-Binding Assay

Prions are comprised principally of aggregates of a misfolded host protein and cause fatal transmissible neurodegenerative disorders of mammals, such as variant Creutzfeldt–Jakob disease in humans and bovine spongiform encephalopathy in cattle. Prions pose significant public health concerns through contamination of blood products and surgical instruments, and can resist conventional hospital sterilization methods. Prion infectivity binds avidly to surgical steel and can efficiently transfer infectivity to a suitable host, and much research has been performed to achieve effective prion decontamination of metal surfaces. Here, we exploit the highly sensitive Standard Steel-Binding Assay (SSBA) to perform a direct comparison of a variety of commercially available decontamination reagents marketed for the removal of prions, alongside conventional sterilization methods. We demonstrate that the efficacy of marketed prion decontamination reagents is highly variable and that the SSBA is able to rapidly evaluate current and future decontamination reagents

Updated projections of future vCJD deaths in the UK

BACKGROUND: Past projections of the future course of the vCJD epidemic in the UK have shown considerable uncertainty, with wide confidence bounds. However, recent vCJD case data have indicated a decrease in the annual incidence of deaths over the past two years. METHODS: A detailed survival model is fitted to the 121 vCJD deaths reported by the end of 2002 stratified by age and calendar time to obtain projections of future incidence. The model is additionally fitted to recent results from a survey of appendix tissues. RESULTS: Our results show a substantial decrease in the uncertainty of the future course of the primary epidemic in the susceptible genotype (MM-homozygous at codon 129 of the prion protein gene), with a best estimate of 40 future deaths (95% prediction interval 9–540) based on fitting to the vCJD case data alone. Additional fitting of the appendix data increases these estimates (best estimate 100, 95% prediction interval 10–2,600) but remains lower than previous projections. CONCLUSIONS: The primary vCJD epidemic in the known susceptible genotype in the UK appears to be in decline

Graphical Approach to Model Reduction for Nonlinear Biochemical Networks

Model reduction is a central challenge to the development and analysis of multiscale physiology models. Advances in model reduction are needed not only for computational feasibility but also for obtaining conceptual insights from complex systems. Here, we introduce an intuitive graphical approach to model reduction based on phase plane analysis. Timescale separation is identified by the degree of hysteresis observed in phase-loops, which guides a “concentration-clamp” procedure for estimating explicit algebraic relationships between species equilibrating on fast timescales. The primary advantages of this approach over Jacobian-based timescale decomposition are that: 1) it incorporates nonlinear system dynamics, and 2) it can be easily visualized, even directly from experimental data. We tested this graphical model reduction approach using a 25-variable model of cardiac β1-adrenergic signaling, obtaining 6- and 4-variable reduced models that retain good predictive capabilities even in response to new perturbations. These 6 signaling species appear to be optimal “kinetic biomarkers” of the overall β1-adrenergic pathway. The 6-variable reduced model is well suited for integration into multiscale models of heart function, and more generally, this graphical model reduction approach is readily applicable to a variety of other complex biological systems

A combined model reduction algorithm for controlled biochemical systems

Background: Systems Biology continues to produce increasingly large models of complex biochemical reaction networks. In applications requiring, for example, parameter estimation, the use of agent-based modelling approaches, or real-time simulation, this growing model complexity can present a significant hurdle. Often, however, not all portions of a model are of equal interest in a given setting. In such situations methods of model reduction offer one possible approach for addressing the issue of complexity by seeking to eliminate those portions of a pathway that can be shown to have the least effect upon the properties of interest. Methods: In this paper a model reduction algorithm bringing together the complementary aspects of proper lumping and empirical balanced truncation is presented. Additional contributions include the development of a criterion for the selection of state-variable elimination via conservation analysis and use of an ‘averaged’ lumping inverse. This combined algorithm is highly automatable and of particular applicability in the context of ‘controlled’ biochemical networks. Results: The algorithm is demonstrated here via application to two examples; an 11 dimensional model of bacterial chemotaxis in Escherichia coli and a 99 dimensional model of extracellular regulatory kinase activation (ERK) mediated via the epidermal growth factor (EGF) and nerve growth factor (NGF) receptor pathways. In the case of the chemotaxis model the algorithm was able to reduce the model to 2 state-variables producing a maximal relative error between the dynamics of the original and reduced models of only 2.8% whilst yielding a 26 fold speed up in simulation time. For the ERK activation model the algorithm was able to reduce the system to 7 state-variables, incurring a maximal relative error of 4.8%, and producing an approximately 10 fold speed up in the rate of simulation. Indices of controllability and observability are additionally developed and demonstrated throughout the paper. These provide insight into the relative importance of individual reactants in mediating a biochemical system’s input-output response even for highly complex networks. Conclusions: Through application, this paper demonstrates that combined model reduction methods can produce a significant simplification of complex Systems Biology models whilst retaining a high degree of predictive accuracy. In particular, it is shown that by combining the methods of proper lumping and empirical balanced truncation it is often possible to produce more accurate reductions than can be obtained by the use of either method in isolation

Observation of electron transfer mediated decay in aqueous solution

Photoionization is at the heart of X ray photoelectron spectroscopy XPS , which gives access to important information on a sample s local chemical environment. Local and non local electronic decay after photoionization in which the refilling of core holes results in electron emission from either the initially ionized species or a neighbour, respectively have been well studied. However, electron transfer mediated decay ETMD , which involves the refilling of a core hole by an electron from a neighbouring species, has not yet been observed in condensed phase. Here we report the experimental observation of ETMD in an aqueous LiCl solution by detecting characteristic secondary low energy electrons using liquid microjet soft XPS. Experimental results are interpreted using molecular dynamics and high level ab initio calculations. We show that both solvent molecules and counterions participate in the ETMD processes, and different ion associations have distinctive spectral fingerprints. Furthermore, ETMD spectra are sensitive to coordination numbers, ion solvent distances and solvent arrangemen