Determinanten eines vorzeitigen Therapieabbruchs: Über den Einfluss psychosozialer und soziodemographischer Faktoren, externer Ereignisse sowie subjektiver Schlafqualität während der stationären qualifizierten Entzugsbehandlung bei Patienten mit Alkohol- und Drogenabhängigkeit auf den Therapieerfolg

Introduction Addiction is a chronic disease that affects millions of individuals worldwide. Qualified detoxification treatment is the first step in inpatient substance abuse treatment. Premature treatment discontinuation is a common complication with negative impact on the long-term course of the disease. Regular treatment completion is therefore a key success criterion of detoxification treatment. The aim of the present doctoral thesis was to determine the influence of socio-demographic environment, international sports events and sleep quality on qualified detoxification treatment outcome. Method Data on the patient’s social environment and medical anamnesis were collected from 832 patients and analysed with respect to the prediction of regular, respectively irregular treatment outcome. The second study aimed to evaluate a potential effect of international sports events on qualified detoxification outcome. Four periods were defined to determine admission and unplanned discharge rates prior to, during and after the European Football Championship. The aim of the third study was to evaluate sleep quality during qualified detoxification treatment and whether bad sleep might serve as a predictor of premature treatment drop-out. Results The drop-out rate in the first study was 37%. A stable social network in terms of family, employment and education and a lower dependency severity positively predicted treatment outcome, whereas an unstable social environment, younger age, male sex and a high number of previous drop-outs were predictive for a premature treatment drop-out. In the second study, the admission rate of male patients increased significantly after the European Football Championship had ended. The drop-out rate measured 26% respectively 30%. In the third study, at admission, impaired sleep was observed in 70% of the patients. Sleep quality at admission predicted the change of sleep quality during qualified detoxification treatment. But sleep quality was not a predictor for unplanned treatment drop-out. With only 7% the drop-out rate was remarkably low. Discussion With the present work, clinical knowledge about predictors of premature treatment drop-out could be expanded. The results indicate that predominantly socially stable patients benefit from the currently established treatment setting. Our results suggest that sports events such as the European Football Championship can trigger unplanned treatment drop-out in male patients. Social and political measures could improve public awareness. In the light of the prevalence of sleep disturbances during detoxification, detoxification treatment should be enriched with individual evaluation of sleep quality and insomnia-specific treatment.Sucht ist eine chronische Erkrankung, die Millionen von Menschen weltweit betrifft. Die Entgiftung ist der erste Schritt in der stationären Alkohol- und Drogentherapie. Der vorzeitige Behandlungsabbruch ist eine häufige Komplikation, die den langfristigen Verlauf der Krankheit negativ beeinflusst. Im Rahmen der vorliegenden Publikationsdissertation wurden anhand von drei Studien potentielle Determinanten eines vorzeitigen Therapieabbruchs untersucht. Methodik Während der Aufnahmeuntersuchung wurden soziodemographische und medizinische Variablen von 832 Suchtpatienten erhoben und nach signifikanten Assoziationen hinsichtlich eines irregulären bzw. regulären Behandlungsabschlusses gesucht. In der zweiten Studie wurde der Einfluss der Fußball-Europameisterschaft 2012 auf die Behandlungstreue untersucht. Dabei wurden vier zu vergleichende Perioden definiert und die Aufnahmen zur qualifizierten Entzugstherapie sowie die vorzeitigen Entlassungen gegenübergestellt. In der dritten Studie wurde unter Verwendung des Pittsburgh Sleep Quality Index (PSQI) untersucht, welchen Einfluss die subjektive Schlafqualität während der qualifizierten Entzugsbehandlung auf den Behandlungsabschluss hat und ob schlechter Schlaf als Prädiktor eines vorzeitigen Therapieabbruchs herangezogen werden kann. Ergebnisse 37% der Patienten brachen die Behandlung in der ersten Studie vorzeitig ab. Weibliches Geschlecht, Partnerschaft, Berufstätigkeit und gute Bildung waren prädiktiv für einen regulären Behandlungsabschluss, während jüngeres Alter, männliches Geschlecht, eine hohe Anzahl vorhergehender Therapieabbrüche sowie Delinquenz als Prädiktoren für einen irregulären Behandlungsabschluss identifiziert werden konnten. Die Abbruchquote der zweiten Studie lag bei 26% bzw. 30%. Bei den männlichen Patienten war nach der Europameisterschaft ein signifikanter Anstieg der Aufnahmen zu beobachten. Die Abbruchquote in der dritten Studie betrug nur 7%. Die Prävalenz von Schlafstörungen (PSQI-Wert > 5) betrug 70%. Die Schlafqualität bei der Aufnahme war prädiktiv für die Schlafqualität bei der Entlassung. Die Schlafqualität während des Entzuges jedoch war nicht prädiktiv für einen irregulären Behandlungsabschluss. Diskussion Anhand der vorliegenden Arbeit konnten die klinischen Kenntnisse über Determinanten eines vorzeitigen Therapieabbruchs erweitert werden. Die Ergebnisse deuten darauf hin, dass vorwiegend sozial stabile Patienten vom derzeitig etablierten Behandlungssetting profitieren. Unsere Untersuchungen legen weiterhin nahe, dass Sportgroßereignisse für männliche Patienten ein Auslöser für einen Therapieabbruch sein können, hier könnten gesellschaftspolitische Maßnahmen zu einer Verbesserung führen. In Anbetracht der Prävalenz von Schlafstörungen während des Entzuges erscheint es sinnvoll, das stationäre Behandlungskonzept um Maßnahmen zur Behandlung von Schlafstörungen zu erweitern

Helicoidal magnetic order in a clean copper oxide spin chain compound

We report susceptibility, specific heat, and neutron diffraction measurements on NaCu$_2$O$_2$, a spin-1/2 chain compound isostructural to LiCu$_2$O$_2$, which has been extensively investigated. Below 13 K, we find a long-range ordered, incommensurate magnetic helix state with a propagation vector similar to that of LiCu$_2$O$_2$. In contrast to the Li analogue, substitutional disorder is negligible in NaCu$_2$O$_2$. We can thus rule out that the helix is induced by impurities, as was claimed on the basis of prior work on LiCu$_2$O$_2$. A spin Hamiltonian with frustrated longer-range exchange interactions provides a good description of both the ordered state and the paramagnetic susceptibility.Comment: 4 pages, 4 figures Improved Fig.1 and 4. Minor rephrasing. Reference adde

Nanogaps with very large aspect ratios for electrical measurements

For nanoscale electrical characterization and device fabrication it is often desirable to fabricate planar metal electrodes separated by large aspect ratio gaps with interelectrode distances well below 100 nm. We demonstrate a self-aligned process to accomplish this goal using a thin Cr film as a sacrificial etch layer. The resulting gaps can be as small as 10 nm and have aspect ratios exceeding 1000, with excellent interelectrode isolation. Such Ti/Au electrodes are demonstrated on Si substrates and are used to examine a voltage-driven transition in magnetite nanostructures. This shows the utility of this fabrication approach even with relatively reactive substrates.Comment: 4 pages, 4 figure

Interplay of bulk and interface effects in the electric-field driven transition in magnetite

Contact effects in devices incorporating strongly-correlated electronic materials are comparatively unexplored. We have investigated the electrically-driven phase transition in magnetite (100) thin films by four-terminal methods. In the lateral configuration, the channel length is less than 2 $\mu$m, and voltage-probe wires $\sim$100 nm in width are directly patterned within the channel. Multilead measurements quantitatively separate the contributions of each electrode interface and the magnetite channel. We demonstrate that on the onset of the transition contact resistances at both source and drain electrodes and the resistance of magnetite channel decrease abruptly. Temperature dependent electrical measurements below the Verwey temperature indicate thermally activated transport over the charge gap. The behavior of the magnetite system at a transition point is consistent with a theoretically predicted transition mechanism of charge gap closure by electric field.Comment: 6 pages, 5 figures, to appear in PR

Incommensurate spin density modulation in a copper-oxide chain compound with commensurate charge order

Neutron diffraction has been used to determine the magnetic structure of Na$_8$Cu$_5$O$_{10}$, a stoichiometric compound containing chains based on edge-sharing CuO$_4$ plaquettes. The chains are doped with 2/5 hole per Cu site and exhibit long-range commensurate charge order with an onset well above room temperature. Below $T_N = 23$ K, the neutron data indicate long-range collinear magnetic order with a spin density modulation whose propagation vector is commensurate along and incommensurate perpendicular to the chains. Competing interchain exchange interactions are discussed as a possible origin of the incommensurate magnetic order

Wigner crystallization in Na(3)Cu(2)O(4) and Na(8)Cu(5)O(10) chain compounds

We report the synthesis of novel edge-sharing chain systems Na(3)Cu(2)O(4) and Na(8)Cu(5)O(10), which form insulating states with commensurate charge order. We identify these systems as one-dimensional Wigner lattices, where the charge order is determined by long-range Coulomb interaction and the number of holes in the d-shell of Cu. Our interpretation is supported by X-ray structure data as well as by an analysis of magnetic susceptibility and specific heat data. Remarkably, due to large second neighbor Cu-Cu hopping, these systems allow for a distinction between the (classical) Wigner lattice and the 4k_F charge-density wave of quantum mechanical origin.Comment: 4 pages, 4 figure

Application of nuclear quadrupole resonance in study of minerals

The NQR method has been used to study some structural and chemical properties of minerals that are difficult or impossible to determine by conventional methods. For example, an X-ray determination commonly integrates the data for all cells, whereas NQR can separate the nearly ideal from highly distorted ones. It can thus give a better picture of the ideal structure and can determine the "degree of defectiveness." The method also has a very high sensitivity for crystallochemical effects. In this connection it has shown that arsenic selenide and orpiment are not strictly isostructural, as was previously thought. Nuclear magnetic resonance and NQR have been particularly successful in order-disorder studies. The latter can also be used as a rapid method of mineral identification. There are important restrictions on mineralogical applications, however: 1) compounds studied must have isotopes with nuclei that carry quadrupole moments; 2) symmetry at the sites of these nuclei must be lower than cubic; 3) concentration of atoms must be about 106 times higher than for the electron paramagnetic resonance method.-E. Ingerson. © 1967 Taylor & Francis Group, LLC

Magnetic excitations and phonons in the spin-chain compound NaCu2O2

We report an inelastic light scattering study of single-crystalline NaCu$_2$O$_2$, a spin-chain compound known to exhibit a phase with helical magnetic order at low temperatures. Phonon excitations were studied as a function of temperature and light polarization, and the phonon frequencies are compared to the results of ab-initio lattice dynamical calculations, which are also reported here. The good agreement between the observed and calculated modes allows an assignment of the phonon eigenvectors. Two distinct high-energy two-magnon features as well as a sharp low-energy one-magnon peak were also observed. These features are discussed in terms of the magnon modes expected in a helically ordered state. Their polarization dependence provides evidence of substantial exchange interactions between two closely spaced spin chains within a unit cell. At high temperatures, the spectral features attributable to magnetic excitations are replaced by a broad, quasielastic mode due to overdamped spin excitations

The origin of hysteresis in resistive switching in magnetite is Joule heating

In many transition metal oxides the electrical resistance is observed to undergo dramatic changes induced by large biases. In magnetite, Fe$_3$O$_4$, below the Verwey temperature, an electric field driven transition to a state of lower resistance was recently found, with hysteretic current-voltage response. We report the results of pulsed electrical conduction measurements in epitaxial magnetite thin films. We show that while the high- to low-resistance transition is driven by electric field, the hysteresis observed in $I-V$ curves results from Joule heating in the low resistance state. The shape of the hysteresis loop depends on pulse parameters, and reduces to a hysteresis-free "jump" of the current provided thermal relaxation is rapid compared to the time between voltage pulses. A simple relaxation time thermal model is proposed that captures the essentials of the hysteresis mechanism.Comment: 7 pages, 6 figure