Polarization in heavy quark decays

In this thesis I concentrate on the angular correlations in top quark decays and their next--to--leading order (NLO) QCD corrections. I also discuss the leading--order (LO) angular correlations in unpolarized and polarized hyperon decays. In the first part of the thesis I calculate the angular correlation between the top quark spin and the momentum of decay products in the rest frame decay of a polarized top quark into a charged Higgs boson and a bottom quark in Two-Higgs-Doublet-Models: $t(uparrow)rightarrow b+H^{+}$. The decay rate in this process is split into an angular independent part (unpolarized) and an angular dependent part (polar correlation). I provide closed form formulae for the ${mathcal O}(alpha_{s})$ radiative corrections to the unpolarized and the polar correlation functions for $m_{b}neq 0$ and $m_{b}=0$. The results for the unpolarized rate agree with the existing results in the literature. The results for the polarized correlations are new. I found that, for certain values of $tanbeta$, the ${mathcal O}(alpha_s)$ radiative corrections to the unpolarized, polarized rates, and the asymmetry parameter can become quite large. In the second part I concentrate on the semileptonic rest frame decay of a polarized top quark into a bottom quark and a lepton pair: $t(uparrow) to X_b + ell^+ + nu_ell$. I analyze the angular correlations between the top quark spin and the momenta of the decay products in two different helicity coordinate systems: system 1a with the $z$--axis along the charged lepton momentum, and system 3a with the $z$--axis along the neutrino momentum. The decay rate then splits into an angular independent part (unpolarized), a polar angle dependent part (polar correlation) and an azimuthal angle dependent part (azimuthal correlation). I present closed form expressions for the ${mathcal O}(alpha_{s})$ radiative corrections to the unpolarized part and the polar and azimuthal correlations in system 1a and 3a for $m_{b}neq 0$ and $m_{b}=0$. For the unpolarized part and the polar correlation I agree with existing results. My results for the azimuthal correlations are new. In system 1a I found that the azimuthal correlation vanishes in the leading order as a consequence of the $(V-A)$ nature of the Standard Model current. The ${mathcal O}(alpha_{s})$ radiative corrections to the azimuthal correlation in system 1a are very small (around 0.24% relative to the unpolarized LO rate). In system 3a the azimuthal correlation does not vanish at LO. The ${mathcal O}(alpha_{s})$ radiative corrections decreases the LO azimuthal asymmetry by around 1%. In the last part I turn to the angular distribution in semileptonic hyperon decays. Using the helicity method I derive complete formulas for the leading order joint angular decay distributions occurring in semileptonic hyperon decays including lepton mass and polarization effects. Compared to the traditional covariant calculation the helicity method allows one to organize the calculation of the angular decay distributions in a very compact and efficient way. This is demonstrated by the specific example of the polarized hyperon decay $Xi^0(uparrow) to Sigma^+ + l^- + bar{nu}_l$ ,($l^-=e^-, mu^-$) followed by the nonleptonic decay $Sigma^+ to p + pi^0$, which is described by a five--fold angular decay distribution.

Synthese und Charakterisierung von Oxidchalkogeniden und Bronzen für die Nanostrukturierung

Ausgehend von der Entdeckung der reversiblen Strukturierung mittels Rastersondenmethoden im Phasensystem Na2O/V2O5/P2O5 wurden im Rahmen dieser Arbeit zwei Ansatzpunkte verfolgt. Einerseits sollten mittels der Schmelzflußelektrolyse einige bereits existierende niederdimensionale Molybdänbronzen mit bekannten elektronischen Übergängen in ausreichend großen Kristallen gezüchtet werden, um sie auf ihre Strukturierungseigenschaften hin zu untersuchen. Gleichzeitig sollte durch Variation versucht werden, neue, bisher unbekannte Bronzen oder reduzierte Oxide zu synthetisieren und charakterisieren. Der zweite Schwerpunkt dieser Arbeit lag in der Synthese und Charakterisierung von Oxidchalkogeniden, bestehend aus einem Seltenerdmetall und einem 3d-Metall von Titan bis hin zu den mittleren Übergangsmetallen. Diese Verbindungen können durch die Kombination der jeweiligen Eigenschaften der oxidischen und chalkogeniden Teilstrukturen völlig neue elektronische und/oder magnetische Eigenschaften aufweisen. Mögliche auftretende Phasenübergänge sind wiederum für Strukturierungsversuche interessant. Die zu den Oxidchalkogeniden durchgeführten Untersuchungen ergaben im Phasensystem Ln/Ti/S/O (Ln = Lanthanoide) insgesamt sechs Verbindungen. Zwei von ihnen, La8Ti9S24O4 und Nd20Ti11S44O6, besitzen als gemeinsames Strukturelement tetranukleare [Ti4(u4-S)2(u2-O)4]-Cluster, bestehend aus vier miteinander über gemeinsame Flächen kondensierte TiS4O2-Oktaeder. Die Titanpositionen innerhalb der Cluster sind mit Ti+3-Ionen besetzt. Beide Verbindungen weisen in einem Temperaturbereich zwischen 150 K und 250 K eine deutlich ausgeprägte Hysterese der magnetischen Suszeptibilität auf, die sich im Falle von La8Ti9S24O4 auf einen Jahn-Teller-Übergang zurückführen läßt. Daneben konnte erstmals eine Serie oxidisch/sulfidisch gemischter Ruddlesden-Popper-Verbindungen mit Ln2Ti2S2O5 (Ln = Pr, Nd, Sm) synthetisiert und charakterisiert werden. Titan liegt als vierwertiges Ion in aus TiSO5-Oktaedern gebildeten Perowskit-Doppelschichten vor. Die neunfach koordinierten Positionen sind mit den Seltenerdmetallionen gefüllt, die zwölffach koordinierten Lagen sind unbesetzt. Bei dem sechsten erhaltene Titanoxidsulfid, La4TiS6.5O1.5, handelt es sich um einen Halbleiter mit einer Bandlücke von etwa 2 eV. Weiterhin gelang es, die Serie Ln2M3S2O8 (Ln = La, Ce, Pr, Nd, Sm; M = Nb, Ta) zu synthetisieren und in ihren physikalischen Eigenschaften zu charakterisieren. Es handelt sich ausnahmslos um Halbleiter mit Bandlücken zwischen E=0.125 eV für La2Nb3S2O8 und E=0.222 eV für Pr2Ta3S2O8. Die Struktur der Oxidsulfide Ce2Ta3S2O8, Pr2Ta3S2O8, Nd2Nb3S2O8 sowie Sm2Ta3S2O8 weist im Gegensatz zu den anderen Verbindungen eine Fehlordnung eines der beiden kristallographisch unabhängigen Nb- bzw. Ta-Atome auf. Daraus resultiert eine Symmetrieerniedrigung von Pnma zu Pbam. Der Einsatz von Europium führte zu einer neuen Modifikation des bronzoiden Oxids EuTa2O6, in der das Europium als Eu+2 vorliegt, wie 151Eu-Mößbauer-Untersuchungen bestätigten. Vor der Durchführung der Kristallzüchtungen mittels der Schmelzflußelektrolysen mußten die benutzen Öfen und Elektrolysezellen geplant und angefertigt werden. Es konnten dann verschiedene blaue, rote und violette Moybdänbronzen (sowie La2Mo2O7) in Kristallen bis zu 25 mm Länge dargestellt werden. Ferner gelang die erste exakte Einkristalluntersuchung der roten Bronze Rb0.33MoO3. Sie verfügt über die höchste d-Elektronen-Lokalisierungsrate aller bekannten roten Bronzen. Die erhaltenen Bronzen wurden teilweise von der Arbeitsgruppe Fuchs, Physikalisches Institut der Westfälischen Wilhelms-Universität Münster, auf ihre Nanostrukturierbarkeit hin untersucht. Dabei ergaben sich zwei verschiedene Strukturierungsmechanismen. Sind es im Fall der blauen Alkalimetall-Molybdänbronzen ausschließlich Lochstrukturen, die entstehen, handelt es sich bei La2Mo2O7 um Hügelstrukturen. Mittels der Schmelzflußelektrolyse konnte auch das gemischtvalente Alkalimetall-Eisenmolybdat NaFe2(MoO4)3 synthetisiert werden. Daneben gelang die Synthese dreier weiterer Alkalimetall-Eisenmolybdate: Cs2Fe2(MoO4)3, NaFe4(MoO4)5 und CsFe5(MoO4)7. Bis auf Cs2Fe2(MoO4)3, welches in der bekannten Langbeinit-Struktur kristallisiert, handelt es sich bei den übrigen Alkalimetall-Eisenmolybdaten um völlig neuartige Käfigverbindungen, bzw. bei CsFe5(MoO4)7 um eine Tunnelverbindung. Die Kristallstrukturen beinhalten kondensierte FeO6-Oktaeder. Im Fall von NaFe2(MoO4)3 lassen sich [Fe2O10]-Einheiten, für NaFe4(MoO4)5 [Fe2O10]- sowie [Fe3O14]-Einheiten, und für CsFe5(MoO4)7 [Fe4O18]-Baueinheiten beobachten. Die Positionen der Fe+2- und Fe+3-Atome in NaFe4(MoO4)5 wurden mit Hilfe einer 57Fe-Mößbauer-Untersuchung bestimmt.

Lattice preferred orientation in omphacite: Examples from the Tauern Window, Austria and the Western Gneiss Region, Norway

It is lively debated how eclogites find their way from deep to mid-crustal levels during exhumation. Different exhumation models for high-pressure and ultrahigh-pressure rocks were suggested in previous studies, based mainly on field observations and less on microstructural studies on the exhumed rocks. The development and improvement of electron microscopy techniques allows it, to focus interest on direct investigations of microstructures and crystallographic properties in eclogites. In this case, it is of importance to study the applicability of crystallographic measurements on eclogites for exhumation processes and to unravel which processes affect eclogite textures. Previous studies suggested a strong relationship between deformation and lattice preferred orientation (LPO) in omphacite but it is still unclear if the deformation is related to the exhumation of eclogites. This study is focused on the questions which processes affect omphacite LPO and if textural investigations of omphacite are applicable for studying eclogite exhumation. Therefore, eclogites from two examples in the Alps and in the Caledonides were collected systematically and investigated with respect to omphacite LPO by using the electron backscattered diffraction (EBSD) technique. Omphacite textures of the Tauern Window (Austria) and the Western Gneiss Region (Norway) were studied to compare lattice preferred orientation with field observations and suggested exhumation models from previous studies. The interpretation of omphacite textures, regarding the deformation regime is mainly based on numerical simulations in previous studies. Omphacite LPO patterns of the Eclogite Zone are clearly independent from any kind of exhumation process. The textures were generated during omphacite growth on the prograde path of eclogite development until metamorphic peak conditions. Field observations in the Eclogite Zone show that kinematics in garnet mica schist, surrounding the eclogites, strongly indicate an extrusion wedge geometry. Stretching lineations show top-N thrusting at the base and a top-S normal faulting with a sinistral shear component at the top of the Eclogite Zone. The different shear sense on both sides of the unit does not affect the omphacite textures in any way. The omphacite lattice preferred orientation patterns of the Western Gneiss Region can not be connected with any exhumation model. The textures were probably generated during the metamorphic peak and reflect the change from subduction to exhumation. Eclogite Zone and Western Gneiss Region differ significantly in size and especially in metamorphic conditions. While the Eclogite Zone is characterized by constant P-T conditions (600-650°C, 20-25 kbar), the Western Gneiss Region contains a wide P-T range from high- to ultrahigh pressure conditions (400-800°C, 20-35 kbar). In contrast to this, the omphacite textures of both units are very similar. This means that omphacite LPO is independent from P-T conditions and therefore from burial depth. Further, in both units, omphacite LPO is independent from grain and subgrain size as well as from any shape preferred orientation (SPO) on grain and subgrain scale. Overall, omphacite lattice preferred orientation are generated on the prograde part of omphacite development. Therefore, textural investigations on omphacite LPO are not applicable to study eclogite exhumation.

Classificazione a faccette di obiettivi formativi dell’insegnamento universitario, nelle discipline umanistiche in Austria, Germania, Italia e Regno Unito

Il processo di riforma a carattere europeo che ha condotto alla nascita di uno Spazio Europeo dell’Istruzione Superiore ha conosciuto diverse tappe fondamentali, fra cui, per esempio, la ripartizione in cicli e l’adozione dei crediti ECTS. Una di queste tappe, ossia il passaggio da una pianificazione della didattica basata sui contenuti ad una basata sui risultati dell’apprendimento, ricopre un ruolo di primo piano nel presente progetto di dottorato. Lo studio qui descritto ha esaminato, da un punto di vista sintattico e semantico, un campione di obiettivi e risultati dell’apprendimento di insegnamenti di alcuni corsi di laurea di primo e secondo ciclo, delle scienze umanistiche, in Austria, Germania, Italia e Regno Unito. L’obiettivo del progetto è proporre uno schema per una classificazione a faccette di obiettivi dell’apprendimento denominato FLOC. Tale schema è adottato per classificare gli obiettivi dell’apprendimento di quattro contesti linguistico-culturali (nei paesi summenzionati), dando vita a FLOC-AT, FLOC-DE, FLOC-IT e FLOC-EN. Queste quattro classificazioni forniscono inoltre il contesto per un’analisi contrastiva multilingue fra unità di obiettivi di apprendimento.

Einfluss der Einzeldosisblisterverpackung von festen Oralia auf die Arzneimitteltherapiesicherheit, Information und Zufriedenheit stationär behandelter Patienten in einer prospektiven, multizentrischen Studie

Bei der vorliegenden Studie wurde die Machbarkeit und Qualität der Arzneimittelverteilung von oralen Arzneimitteln in Einzeldosisblisterverpackungen je abgeteilte Arzneiform (EVA) untersucht.rnDie Studie wurde als offene, vergleichende, prospektive und multizentrische Patientenstudie durchgeführt. Als Studienmedikation standen Diovan®, CoDiovan® und Amlodipin in der EVA-Verpackung zur Verfügung. Die Verteilfehlerrate in der EVA- und Kontroll-Gruppe stellte den primären Zielparameter dar. Das Patientenwissen, die Patientenzufriedenheit und die Praktikabilität des EVA-Systems, sowie die Zufriedenheit der Pflegekräfte wurden mithilfe von Fragebogen evaluiert. Insgesamt wurden 2070 gültige Tablettenvergaben bei 332 Patienten in sechs verschiedenen Krankenhäusern geprüft. Es wurde in der EVA-Gruppe ein Verteilungsfehler von 1,8% und in der Kontroll-Gruppe von 0,7% ermittelt. Bei den Patienten-Fragebogen konnten insgesamt 292 Fragebogen ausgewertet werden. Die Ergebnisse zeigten einen ungenügenden Informationsstand der Patienten über ihre aktuellen, oralen Arzneimittel. In den 80 ausgefüllten Pflegekräfte-Fragebogen gaben über 80% an, dass Fehler beim Richten durch das EVA-System besser erkannt werden können. rnZusammenfassend kann gesagt werden, dass die erhöhte Fehlerrate in der EVA-Gruppe im Vergleich zur Kontroll-Gruppe durch mehrere Störfaktoren bedingt wurde. Grundsätzlich konnte eine sehr positive Resonanz auf das EVA-System bei den Patienten und den Pflegekräften beobachtet werden. rn

Training-related modulations of the autonomic nervous system in endurance athletes: is female gender cardioprotective?

The risk of sudden death is increased in athletes with a male predominance. Regular physical activity increases vagal tone, and may protect against exercise-induced ventricular arrhythmias. We investigated training-related modulations of the autonomic nervous system in female and male endurance athletes. Runners of a 10-mile race were invited. Of 873 applicants, 68 female and 70 male athletes were randomly selected and stratified according to their average weekly training hours in a low (≤4 h) and high (>4 h) volume training group. Analysis of heart rate variability was performed over 24 h. Spectral components (high frequency [HF] and low frequency [LF] power in normalized units) were analyzed for hourly 5 min segments and averaged for day- and nighttime. One hundred and fourteen athletes (50 % female, mean age 42 ± 7 years) were included. No significant gender difference was observed for training volume and 10-mile race time. Over the 24-h period, female athletes exhibited a higher HF and lower LF power for each hourly time-point. Female gender and endurance training hours were independent predictors of a higher HF and lower LF power. In female athletes, higher training hours were associated with a higher HF and lower LF power during nighttime. In male athletes, the same was true during daytime. In conclusion, female and male athletes showed a different circadian pattern of the training-related increase in markers of vagal tone. For a comparable amount of training volume, female athletes maintained their higher markers of vagal tone, possibly indicating a superior protection against exercise-induced ventricular arrhythmias.

Long-term effects of endovascular angioplasty on orthostatic vasocutaneous autoregulation in patients with peripheral atherosclerosis

OBJECTIVE: To test the hypothesis that endovascular revascularization of femoropopliteal lesions improves the impaired venoarteriolar response (VAR) in patients with atherosclerosis. METHODS: We prospectively compared VARs in 15 healthy controls (18 legs) and 14 patients (17 legs) with mild to moderate peripheral arterial disease before and after successful peripheral endovascular angioplasty of femoropopliteal lesions. In all subjects, foot skin blood flow was assessed by laser Doppler flowmetry in the horizontal (HBF) and sitting (SBF) positions. VAR was calculated as (HBF - SBF)/HBF x 100. RESULTS: In patients with peripheral arterial disease, mean HBF (in arbitrary units [AU]; mean +/- SD) was similar before (25.6 +/- 15.3 AU) and after (27.0 +/- 16.4 AU) angioplasty (P = .67), whereas SBF was significantly lower after than before the endovascular procedure (11.6 +/- 7.7 AU to 18.4 +/- 14.1 AU; P < .05). Intragroup differences between SBF and HBF were significant before and after angioplasty (P < .001). VAR was higher after angioplasty (55.1% +/- 21.2%) compared with VAR before intervention (33.4% +/- 20.2%; P = .015). Although VAR increased after the intervention, VAR was still lower than in healthy controls (68.4% +/- 20.5%; P = .025). During the 6 months of follow-up, the ankle-brachial index and VAR remained unchanged (P > .05). CONCLUSIONS: Patients with mild to moderate peripheral arterial disease have an impaired orthostatic autoregulation that improves after successful endovascular revascularization of femoropopliteal obstructive lesions. The effect on VAR is sustained in the absence of restenosis.

A randomized comparison of the safety and efficacy of once-daily gentamicin or thrice-daily gentamicin in combination with ticarcillin-clavulanate

PURPOSE: The primary purpose of the clinical trial was to assess the safety and efficacy of once-a-day compared with three-times-a-day gentamicin in patients with serious infections who had protocol-determined peak serum aminoglycoside concentrations. PATIENTS AND METHODS: A total of 249 hospitalized patients with suspected or proven serious infections were randomized in a 2:2:1 ratio to gentamicin given three times a day with ticarcillin-clavulanate (TC), gentamicin once a day with TC, or ticarcillin-clavulanate (TC) alone. The gentamicin once-a-day dosage for patients with estimated creatinine clearance values of > or =80 mL/min was 5.1 mg/kg. With lower creatinine clearance estimates, the mg/kg dosage of gentamicin was decreased, and the dosage intervals (once daily or three times a day) were maintained. Evaluability required documentation of achievement of protocol-defined peak serum gentamicin levels. RESULTS: Of the total 175 evaluable patients, there were no significant differences found between treatment regimens with respect to clinical or microbiologic efficacy. Bedside audiometry proved impractical due to the frequency of altered mental state in ill patients. Based on the traditional increase in serum creatinine values from baseline values, no differences in renal toxicity between the treatment groups was identified. When changes in renal function were reanalyzed based on maintaining, as opposed to worsening, of renal function, preservation of renal function was better in the gentamicin once-a-day patients as opposed to the gentamicin three-times-a-day patients, P <0.01. CONCLUSIONS: Gentamicin once a day plus TC, gentamicin three times a day plus TC, and TC alone had similar effects in seriously ill hospitalized patients. The incidence of nephrotoxicity was similar in the three treatment groups. Using a nonvalidated post-hoc analysis, renal function was better preserved in gentamicin once-a-day + TC and TC-only patients as opposed to gentamicin three-times-a-day + TC.

Basic control of reperfusion effectively protects against reperfusion injury in a realistic rodent model of acute limb ischemia

BACKGROUND: Reperfusion injury is insufficiently addressed in current clinical management of acute limb ischemia. Controlled reperfusion carries an enormous clinical potential and was tested in a new reality-driven rodent model. METHODS AND RESULTS: Acute hind-limb ischemia was induced in Wistar rats and maintained for 4 hours. Unlike previous tourniquets models, femoral vessels were surgically prepared to facilitate controlled reperfusion and to prevent venous stasis. Rats were randomized into an experimental group (n=7), in which limbs were selectively perfused with a cooled isotone heparin solution at a limited flow rate before blood flow was restored, and a conventional group (n=7; uncontrolled blood reperfusion). Rats were killed 4 hours after blood reperfusion. Nonischemic limbs served as controls. Ischemia/reperfusion injury was significant in both groups; total wet-to-dry ratio was 159+/-44% of normal (P=0.016), whereas muscle viability and contraction force were reduced to 65+/-13% (P=0.016) and 45+/-34% (P=0.045), respectively. Controlled reperfusion, however, attenuated reperfusion injury significantly. Tissue edema was less pronounced (132+/-16% versus 185+/-42%; P=0.011) and muscle viability (74+/-11% versus 57+/-9%; P=0.004) and contraction force (68+/-40% versus 26+/-7%; P=0.045) were better preserved than after uncontrolled reperfusion. Moreover, subsequent blood circulation as assessed by laser Doppler recovered completely after controlled reperfusion but stayed durably impaired after uncontrolled reperfusion (P=0.027). CONCLUSIONS: Reperfusion injury was significantly alleviated by basic modifications of the initial reperfusion period in a new in vivo model of acute limb ischemia. With this model, systematic optimizations of according protocols may eventually translate into improved clinical management of acute limb ischemia.

In vitro comparison of the complement-scavenging capacity of different intravenous immunoglobulin preparations

BACKGROUND AND OBJECTIVES: Complement inhibition is considered important in the mechanism of action of intravenous immunoglobulin (IVIG) in a number of inflammatory and autoimmune disorders. The capacity of different IVIG preparations to 'scavenge' activated C3 and thereby inhibit complement activation was assessed by a new in vitro assay. MATERIALS AND METHODS: Diluted human serum as a complement source, with or without addition of different concentrations of IVIG, was incubated in microtitre plates coated with heat-aggregated human IgG. Complement scavenging was measured by detecting reduced C3 binding and determining fluid phase C3b-IgG complex formation. Complement activation induced by the IVIG preparations was measured as C5a formation. RESULTS: All IVIG preparations exhibited a dose-dependent inhibition of C3b deposition, correlating strongly with binding of C3b to fluid-phase IgG, but the extent of complement scavenging varied considerably between different IVIG preparations. At an IVIG concentration of 0.9 mg/ml, the inhibition of C3b deposition ranged from 72 +/- 16% to 22 +/- 4.1%. The reduction of C3b deposition on the complement-activating surface was not due to IVIG-induced complement activation in the fluid phase, as shown by the low C5a formation in the presence of serum. CONCLUSION: In vitro analysis allows comparison of the complement-inhibitory properties of IVIG preparations. The extent of complement scavenging varies between the products.

Pathways that make voices - White matter changes in auditory hallucinations

BACKGROUND: The origin of auditory hallucinations, which are one of the core symptoms of schizophrenia, is still a matter of debate. It has been hypothesized that alterations in connectivity between frontal and parietotemporal speech-related areas might contribute to the pathogenesis of auditory hallucinations. These networks are assumed to become dysfunctional during the generation and monitoring of inner speech. Magnetic resonance diffusion tensor imaging is a relatively new in vivo method to investigate the directionality of cortical white matter tracts. OBJECTIVE: To investigate, using diffusion tensor imaging, whether previously described abnormal activation patterns observed during auditory hallucinations relate to changes in structural interconnections between the frontal and parietotemporal speech-related areas. METHODS: A 1.5 T magnetic resonance scanner was used to acquire twelve 5-mm slices covering the Sylvian fissure. Fractional anisotropy was assessed in 13 patients prone to auditory hallucinations, in 13 patients without auditory hallucinations, and in 13 healthy control subjects. Structural magnetic resonance imaging was conducted in the same session. Based on an analysis of variance, areas with significantly different fractional anisotropy values between groups were selected for a confirmatory region of interest analysis. Additionally, descriptive voxel-based t tests between the groups were computed. RESULTS: In patients with hallucinations, we found significantly higher white matter directionality in the lateral parts of the temporoparietal section of the arcuate fasciculus and in parts of the anterior corpus callosum compared with control subjects and patients without hallucinations. Comparing patients with hallucinations with patients without hallucinations, we found significant differences most pronounced in the left hemispheric fiber tracts, including the cingulate bundle. CONCLUSION: Our findings suggest that during inner speech, the alterations of white matter fiber tracts in patients with frequent hallucinations lead to abnormal coactivation in regions related to the acoustical processing of external stimuli. This abnormal activation may account for the patients' inability to distinguish self-generated thoughts from external stimulation.

Transition from nerve stimulator to sonographically guided axillary brachial plexus anesthesia in hand surgery: block quality and patient satisfaction during the transition period

OBJECTIVES Sonographic guidance for peripheral nerve anesthesia has proven increasingly successful in clinical practice; however, fears that a change to sonographically guided regional anesthesia may impair the block quality and operating room work flow persist in certain units. In this retrospective cohort study, block quality and patient satisfaction during the transition period from nerve stimulator to sonographic guidance for axillary brachial plexus anesthesia in a tertiary referral center were investigated. METHODS Anesthesia records of all patients who had elective surgery of the wrist or hand during the transition time (September 1, 2006-August 25, 2007) were reviewed for block success, placement time, anesthesiologist training level, local anesthetic volume, and requirement of additional analgesics. Postoperative records were reviewed, and patient satisfaction was assessed by telephone interviews in matched subgroups. RESULTS Of 415 blocks, 341 were sonographically guided, and 74 were nerve stimulator guided. Sonographically guided blocks were mostly performed by novices, whereas nerve stimulator-guided blocks were performed by advanced users (72.3% versus 14%; P < .001). Block performance times and success rates were similar in both groups. In sonographically guided blocks, significantly less local anesthetics were applied compared to nerve stimulator-guided blocks (mean ± SD, 36.1 ± 7.1 versus 43.9 ± 6.1 mL; P< .001), and less opioids were required (fentanyl, 66.1 ± 30 versus 90 ± 62 μg; P< .001). Interviewed patients reported significantly less procedure-related discomfort, pain, and prolonged procedure time when block placement was sonographically guided (2% versus 20%; P = .002). CONCLUSIONS Transition from nerve stimulator to sonographic guidance for axillary brachial plexus blocks did not change block performance times or success rates. Patient satisfaction was improved even during the early institutional transition period.

A compact and portable deposition chamber to study nanoparticles in air-exposed tissue

BACKGROUND Epidemiological studies show that elevated levels of particulate matter in ambient air are highly correlated with respiratory and cardiovascular diseases. Atmospheric particles originate from a large number of sources and have a highly complex and variable composition. An assessment of their potential health risks and the identification of the most toxic particle sources would require a large number of investigations. Due to ethical and economic reasons, it is desirable to reduce the number of in vivo studies and to develop suitable in vitro systems for the investigation of cell-particle interactions. METHODS We present the design of a new particle deposition chamber in which aerosol particles are deposited onto cell cultures out of a continuous air flow. The chamber allows for a simultaneous exposure of 12 cell cultures. RESULTS Physiological conditions within the deposition chamber can be sustained constantly at 36-37°C and 90-95% relative humidity. Particle deposition within the chamber and especially on the cell cultures was determined in detail, showing that during a deposition time of 2 hr 8.4% (24% relative standard deviation) of particles with a mean diameter of 50 nm [mass median diameter of 100 nm (geometric standard deviation 1.7)] are deposited on the cell cultures, which is equal to 24-34% of all charged particles. The average well-to-well variability of particles deposited simultaneously in the 12 cell cultures during an experiment is 15.6% (24.7% relative standard deviation). CONCLUSIONS This particle deposition chamber is a new in vitro system to investigate realistic cell-particle interactions at physiological conditions, minimizing stress on the cell cultures other than from deposited particles. A detailed knowledge of particle deposition characteristics on the cell cultures allows evaluating reliable dose-response relationships. The compact and portable design of the deposition chamber allows for measurements at any particle sources of interest.

Functions and intramolecular interactions of ribosomal RNA in decoding of termination codons

Two regions in the 3$\prime$ domain of 16S rRNA (the RNA of the small ribosomal subunit) have been implicated in decoding of termination codons. Using segment-directed PCR random mutagenesis, I isolated 33 translational suppressor mutations in the 3$\prime$ domain of 16S rRNA. Characterization of the mutations by both genetic and biochemical methods indicated that some of the mutations are defective in UGA-specific peptide chain termination and that others may be defective in peptide chain termination at all termination codons. The studies of the mutations at an internal loop in the non-conserved region of helix 44 also indicated that this structure, in a non-conserved region of 16S rRNA, is involved in both peptide chain termination and assembly of 16S rRNA.^ With a suppressible trpA UAG nonsense mutation, a spontaneously arising translational suppressor mutation was isolated in the rrnB operon cloned into a pBR322-derived plasmid. The mutation caused suppression of UAG at two codon positions in trpA but did not suppress UAA or UGA mutations at the same trpA positions. The specificity of the rRNA suppressor mutation suggests that it may cause a defect in UAG-specific peptide chain termination. The mutation is a single nucleotide deletion (G2484$\Delta$) in helix 89 of 23S rRNA (the large RNA of the large ribosomal subunit). The result indicates a functional interaction between two regions of 23S rRNA. Furthermore, it provides suggestive in vivo evidence for the involvement of the peptidyl-transferase center of 23S rRNA in peptide chain termination. The $\Delta$2484 and A1093/$\Delta$2484 (double) mutations were also observed to alter the decoding specificity of the suppressor tRNA lysT(U70), which has a mutation in its acceptor stem. That result suggests that there is an interaction between the stem-loop region of helix 89 of 23S rRNA and the acceptor stem of tRNA during decoding and that the interaction is important for the decoding specificity of tRNA.^ Using gene manipulation procedures, I have constructed a new expression vector to express and purify the cellular protein factors required for a recently developed, realistic in vitro termination assay. The gene for each protein was cloned into the newly constructed vector in such a way that expression yielded a protein with an N-terminal affinity tag, for specific, rapid purification. The amino terminus was engineered so that, after purification, the unwanted N-terminal tag can be completely removed from the protein by thrombin cleavage, yielding a natural amino acid sequence for each protein. I have cloned the genes for EF-G and all three release factors into this new expression vector and the genes for all the other protein factors into a pCAL-n expression vector. These constructs will allow our laboratory group to quickly and inexpensively purify all the protein factors needed for the new in vitro termination assay. (Abstract shortened by UMI.) ^

Diurnal variations in middle-atmospheric water vapor by ground-based microwave radiometry

Abstract. In this paper, we compare the diurnal variations in middle-atmospheric water vapor as measured by two ground-based microwave radiometers in the Alpine region near Bern, Switzerland. The observational data set is also compared to data from the chemistry–climate model WACCM. Due to the small diurnal variations of usually less than 1%, averages over extended time periods are required. Therefore, two time periods of five months each, December to April and June to October, were taken for the comparison. The diurnal variations from the observational data agree well with each other in amplitude and phase. The linear correlation coefficients range from 0.8 in the upper stratosphere to 0.5 in the upper mesosphere. The observed diurnal variability is significant at all pressure levels within the sensitivity of the instruments. Comparing our observations with WACCM, we find that the agreement of the phase of the diurnal cycle between observations and model is better from December to April than from June to October. The amplitudes of the diurnal variations for both time periods increase with altitude in WACCM, but remain approximately constant at 0.05 ppm in the observations. The WACCM data are used to separate the processes that lead to diurnal variations in middle-atmospheric water vapor above Bern. The dominating processes were found to be meridional advection below 0.1 hPa, vertical advection between 0.1 and 0.02 hPa and (photo-)chemistry above 0.02 hPa. The contribution of zonal advection is small. The highest diurnal variations in water vapor as seen in the WACCM data are found in the mesopause region during the time period from June to October with diurnal amplitudes of 0.2 ppm (approximately 5% in relative units).