Exploring the functional domain and the target of the tetanus toxin light chain in neurohypophysial terminals

The tetanus toxin light chain blocks calcium induced vasopressin release from neurohypophysial nerve terminals. Here we show that histidine residue 233 within the putative zinc binding motif of the tetanus toxin light chain is essential for the inhibition of exocytosis, in the rat. The zinc chelating agent dipicolinic acid as well as captopril, an inhibitor of zinc-dependent peptidases, counteract the effect of the neurotoxin. Synthetic peptides, the sequences of which correspond to motifs present in the cytoplasmic domain of the synaptic vesicle membrane protein synaptobrevin 1 and 2, prevent the effect of the tetanus toxin light chain. Our results indicate that zinc bound to the zinc binding motif constitutes the active site of the tetanus toxin light chain. Moreover they suggest that cleavage of synaptobrevin by the neurotoxin causes the inhibition of exocytotic release of vasopressin from secretory granules

Transgender Transitioning and Change of Self-Reported Sexual Orientation

Objective: Sexual orientation is usually considered to be determined in early life and stable in the course of adulthood. In contrast, some transgender individuals report a change in sexual orientation. A common reason for this phenomenon is not known. Methods: We included 115 transsexual persons (70 male-to-female "MtF" and 45 female-to-male "FtM") patients from our endocrine outpatient clinic, who completed a questionnaire, retrospectively evaluating the history of their gender transition phase. The questionnaire focused on sexual orientation and recalled time points of changes in sexual orientation in the context of transition. Participants were further asked to provide a personal concept for a potential change in sexual orientation. Results: In total, 32.9% (n = 23) MtF reported a change in sexual orientation in contrast to 22.2% (n = 10) FtM transsexual persons (p = 0.132). Out of these patients, 39.1% (MtF) and 60% (FtM) reported a change in sexual orientation before having undergone any sex reassignment surgery. FtM that had initially been sexually oriented towards males (= androphilic), were significantly more likely to report on a change in sexual orientation than gynephilic, analloerotic or bisexual FtM (p = 0.012). Similarly, gynephilic MtF reported a change in sexual orientation more frequently than androphilic, analloerotic or bisexual MtF transsexual persons (p = 0.05). Conclusion: In line with earlier reports, we reveal that a change in self-reported sexual orientation is frequent and does not solely occur in the context of particular transition events. Transsexual persons that are attracted by individuals of the opposite biological sex are more likely to change sexual orientation. Qualitative reports suggest that the individual's biography, autogynephilic and autoandrophilic sexual arousal, confusion before and after transitioning, social and self-acceptance, as well as concept of sexual orientation itself may explain this phenomenon

Coolant mixing in pressurized water reactors

For the analysis of boron dilution transients and main steam line break scenarios the modelling of the coolant mixing inside the reactor vessel is important. The reactivity insertion due to overcooling or deboration depends strongly on the coolant temperature and boron concentration. The three-dimensional flow distribution in the downcomer and the lower plenum of PWR's was calculated with a computational fluid dynamics (CFD) code (CFX-4). Calculations were performed for the PWR's of SIEMENS KWU, Westinghouse and VVER-440 / V-230 type. The following important factors were identified: exact representation of the cold leg inlet region (bend radii etc.), extension of the downcomer below the inlet region at the PWR Konvoi, obstruction of the flow by the outlet nozzles penetrating the downcomer, etc. The k- turbulence model was used. Construction elements like perforated plates in the lower plenum have large influence on the velocity field. It is impossible to model all the orifi! ces in the perforated plates. A porous region model was used to simulate perforated plates and the core. The porous medium is added with additional body forces to simulate the pressure drop through perforated plates in the VVER-440. For the PWR Konvoi the whole core was modelled with porous media parameters. The velocity fields of the PWR Konvoi calculated for the case of operation of all four main circulation pumps show a good agreement with experimental results. The CFD-calculation especially confirms the back flow areas below the inlet nozzles. The downcomer flow of the Russian VVER-440 has no recirculation areas under normal operation conditions. By CFD calculations for the downcomer and the lower plenum an analytical mixing model used in the reactor dynamic code DYN3D was verified. The measurements, the analytical model and the CFD-calculations provided very well agreeing results particularly for the inlet region. The difficulties of analytical solutions and the uncertainties of turbulence models for the numerical solutions require additional experiments. Therefore a 1:5 scaled plexiglas model is under construction at RC Rossendorf. The model can be used variably for PWR's of KONVOI- and EPR- types including the primary loops. The measurements of the mixing effects will be performed with modern wire mesh sensors based on conductivity differences and LDA is used to measure the flow conditions

Medium effects on phi decays to dilepton and kaon-antikaon pairs in relativistic heavy ion reactions

We consider the role of rescattering of secondary kaons on the dilepton branching ratio of the phi meson. In-medium mass modifications and broadening of kaons and phi mesons are taken into account. We find in the framework of a Bjorken scenario for the time evolution of the expanding fireball that the phi yield from dimuons is moderately or at least only slightly enhanced compared to that from kaon-antikaon pairs. The relation to experimental yields measured by the NA49, NA50 and CERES Collaborations at CERN SPS and the PHENIX Collaboration at RHIC is discussed.Comment: 6 pages with 2 figures, accepted for publication in Eur. Phys. J.

Kühlmittelvermischung in Druckwasserreaktoren Teil 1: Möglichkeiten geschlossener analytischer Lösungen und Simulation der Vermischung mit CFX-4

Ziel des Vorhabens war die analytische und numerische Simulation der Kühlmittelvermischung im Ringraum und unteren Plenum von Druckwasserreaktoren. Generell ist die Kühlmittelvermischung relevant für zwei große Störfallgruppen - Borsäureverdünnungsstörfälle und Kaltwassertransienten. Zur Untersuchung der Vermischungsphänomene aus diesen Störfallszenarien wurde die Rossendorfer Versuchsanlage ROCOM konzipiert, die ein 1:5 skaliertes Plexiglasmodell des DWR Konvoi darstellt, in dem auch Geschwindigkeitsmessungen mit Hilfe von LDA-Technik möglich sind. Konstruktion, Errichtung und meßtechnische Ausstattung von ROCOM erfolgten in einem 2. Teil des Vorhabens. Im Vorfeld der Errichtung des ROCOM-Versuchsstandes wurden mit Hilfe des dreidimensionalen Strömungsberechnungsprogrammes CFX-4 Skalierungseffekte untersucht. Die Vergleichsrechnungen belegten, daß eine 1:5 Skalierung ausreichend ist. Nach dem Aufbau des Versuchsstandes und der Inbetriebnahme im 2. Teil des Vorhabens wurden die Vorausberechnungen anhand von experimentellen Ergebnissen bestätigt. Es wurde weiterhin ein Verfahren zur vereinfachten analytischen 2D-Beschreibung des Strömungsfeldes im Ringraum von Druckwasserreaktoren aufgestellt. Es beruht auf der Potentialtheorie, wobei Quellen an den Kühlmitteleintrittspositionen und Wirbel unter Beachtung der Randbedingungen der typischen Ringspaltgeometrie von DWR überlagert wurden. Der Schwerpunkt des Projektes lag jedoch in der numerischen Simulation der Kühlmittelvermischung unterschiedlicher Reaktoranlagen mit CFX-4 und der Validierung des Rechenprogramms anhand von Vermischungsexperimenten. Dabei wurden sowohl stationäre Schleifendurchsätze bei Nominalbetrieb und Teilschleifenbetrieb bzw. transiente Strömungsbedingungen der Reaktortypen DWR Konvoi und WWER-440 untersucht. Die Ergebnisse der CFX-4 Rechnungen im Vergleich mit den Leitfähigkeits- bzw. LDA-Messungen sind im Abschlußbericht dokumentiert. Grundlage für diesen Abschlußbericht ist eine Promotionsarbeit von T. Höhne zum gleichnamigen Thema im Rahmen des Kompetenzerhaltungsprogrammes Kerntechnik

Isobaric and Isochoric Heat Capacities of Imidazolium-Based and Pyrrolidinium-Based Ionic Liquids as Function of Temperature: Modeling of Isobaric Heat Capacity

International audienceThe isobaric and isochoric heat capacities of seven 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides, two 1-alkyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imides, and two bis(1-alkyl-3-methylimidazolium) tetrathiocyanatocobaltates were determined at atmospheric pressure in the temperature range from 293.15 to 323.15 K. The isobaric heat capacities were determined by means of differential scanning calorimetry, whereas isochoric heat capacities were determined along with isothermal compressibilities indirectly by means of the acoustic method from the speed of sound and density measurements. Based on the experimental data, as expected, the isobaric heat capacity increases linearly with increasing alkyl chain length in the cation of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides and no odd and even carbon number effect is observed. After critical comparison of the obtained data with the available literature data, the most reliable values are recommended. It has been also shown that, although the COSMOthermX calculations underestimated the isobaric heat capacity values whatever the temperature and the ionic liquid structure, the approach used during this work may be applied to estimate physical properties of non-single-charged ions as well. Additionally, based on the speeds of sound the thermal conductivities were calculated using a modified Bridgman relation

Innovating the collection of open-ended answers: The linguistic and content characteristics of written and oral answers to political attitude questions

The rapid increase in smartphone surveys and technological developments open novel opportunities for collecting survey answers. One of these opportunities is the use of open-ended questions with requests for oral instead of written answers, which may facilitate the answer process and result in more in-depth and unfiltered information. Whereas it is now possible to collect oral answers on smartphones, we still lack studies on the impact of this novel answer format on the characteristics of respondents' answers. In this study, we compare the linguistic and content characteristics of written versus oral answers to political attitude questions. For this purpose, we conducted an experiment in a smartphone survey (N = 2402) and randomly assigned respondents to an answer format (written or oral). Oral answers were collected via the open source ‘SurveyVoice (SVoice)’ tool, whereas written answers were typed in via the smartphone keypad. Applying length analysis, lexical structure analysis, sentiment analysis and structural topic models, our results reveal that written and oral answers differ substantially from each other in terms of lengths, structures, sentiments and topics. We find evidence that written answers are characterized by an intentional and conscious answering, whereas oral answers are characterized by an intuitive and spontaneous answering.publishedVersio

Evaluating the effect of apex position and rocker in curved rocker shoes

Curved rocker shoes are designed with a contoured outsole which can be characteristics by three principle design features: rocker angle, apex angle and apex position. Although these shoes are routinely prescribed to reduce in-shoe pressure in patients with diabetes, there is only minimal scientific evidence to inform the choice of value for each of the three design features. Results from a previous study [1], suggested that a 95° apex angle may be the best compromise for offloading the different regions of the forefoot. The results of this study also suggested that higher rocker angle may lead to decrease pressure, however, this study did not quantify the precise effect of rocker angle and apex position in shoes with a 95° apex angle

Crossed cerebellar diaschisis in acute ischemic stroke: Impact on morphologic and functional outcome

Crossed cerebellar diaschisis (CCD) is the phenomenon of hypoperfusion and hypometabolism of the contralateral cerebellar hemisphere caused by dysfunction of the related supratentorial region. Our aim was to analyze its influence on morphologic and functional outcome in acute ischemic stroke. Subjects with stroke caused by a large vessel occlusion of the anterior circulation were selected from an initial cohort of 1644 consecutive patients who underwent multiparametric CT including whole-brain CT perfusion. Two experienced readers evaluated the posterior fossa in terms of CCD absence (CCD-) or presence (CCD+). A total of 156 patients formed the study cohort with 102 patients (65.4%) categorized as CCD- and 54 (34.6%) as CCD+. In linear and logistic regression analyses, no significant association between CCD and final infarction volume (beta = -0.440, p = 0.972), discharge mRS2 (OR = 1.897, p = 0.320), or 90-day mRS <= 2 (OR = 0.531, p = 0.492) was detected. CCD+ patients had larger supratentorial cerebral blood flow deficits (median: 164 ml vs. 115 ml;p = 0.001) compared to CCD-patients. Regarding complications, CCD was associated with a higher rate of parenchymal hematomas (OR = 4.793, p = 0.035). In conclusion, CCD is frequently encountered in acute ischemic stroke caused by large vessel occlusion of the anterior circulation. CCD was associated with the occurrence of parenchymal hematoma in the ipsilateral cerebral infarction but did not prove to significantly influence patient outcome