Immobilized stem–loop structured probes as conformational switches for enzymatic detection of microbial 16S rRNA

We have designed and evaluated novel DNA stem–loop structured probes for enzymatic detection of nucleic acid targets. These probes constitute a novel class of conformational switches for enzymatic activity, which in the absence of a target sterically shield an affinity label and upon hybridization of the target to the recognition sequence that forms the loop of the probe restore accessibility of the label for the binding of a reporter enzyme. Analysis of probe characteristics revealed stem stability as the most important parameter governing detection functionality, while other factors such as the length of linker molecules attaching the label to the stem–loop structure and the nature of the solid support proved to be less critical. Apparently, the bulky nature of the reporter enzyme facilitates shielding of the label in the absence of the target, thereby conferring considerable structural tolerance to the conformational switch system. The stem–loop structured probes allow sensitive detection of unlabeled nucleic acid targets. Employing a microtiter assay format, 4 ng of bacterial 16S ribosomal RNA corresponding to 8 fmol could be detected, which can be compared favorably with current immobilized molecular beacon concepts based on fluorescence detection

Oral diabetes medication monotherapy and short-term mortality in individuals with type 2 diabetes and coronary artery disease

Objective To determine whether sulfonylurea use, compared with non-sulfonylurea oral diabetes medication use, was associated with 2-year mortality in individuals with well-controlled diabetes and coronary artery disease (CAD). Research design and methods We studied 5352 US veterans with type 2 diabetes, obstructive CAD on coronary angiography, hemoglobin A1c ≤7.5% at the time of catheterization, and taking zero or one oral diabetes medication (categorized as no medications, non-sulfonylurea medication, or sulfonylurea). We estimated the association between medication category and 2-year mortality using inverse probability of treatment-weighted (IPW) standardized mortality differences and IPW multivariable Cox proportional hazards regression. Results 49%, 35%, and 16% of the participants were on no diabetes medications, non-sulfonylurea medications, and sulfonylureas, respectively. In individuals on no medications, non-sulfonylurea medications, and sulfonylureas, the unadjusted mortality rates were 6.6%, 5.2%, and 11.9%, respectively, and the IPW-standardized mortality rates were 5.9%, 6.5%, and 9.7%, respectively. The standardized absolute 2-year mortality difference between non-sulfonylurea and sulfonylurea groups was 3.2% (95% CI 0.7 to 5.7) (p=0.01). In Cox proportional hazards models, the point estimate suggested that sulfonylurea use might be associated with greater hazard of mortality than non-sulfonylurea medication use, but this finding was not statistically significant (HR 1.38 (95% CI 1.00 to 1.93), p=0.05). We did not observe significant mortality differences between individuals on no diabetes medications and non-sulfonylurea users. Conclusions Sulfonylurea use was common (nearly one-third of those taking medications) and was associated with increased 2-year mortality in individuals with obstructive CAD. The significance of the association between sulfonylurea use and mortality was attenuated in fully adjusted survival models. Caution with sulfonylurea use may be warranted for patients with well-controlled diabetes and CAD, and metformin or newer diabetes medications with cardiovascular safety data could be considered as alternatives when individualizing therapy

Demokratie und Technikfolgenabschätzung : Praktische Herausforderungen und konzeptionelle Konsequenzen

Technikfolgenabschätzung (TA) ist vor über 50 Jahren zur Unterstützung demokratischer Meinungsbildung und Entscheidungsfindung entstanden. Sie hat sich seitdem in demokratischen Gesellschaften westlichen Typs weiterentwickelt und diversifiziert. Dieses Modell ist seit einigen Jahren mit Herausforderungen konfrontiert, darunter: (1) In fast allen westlichen Ländern wird anlässlich des Erstarkens populistischer Strömungen von einer Krise der Demokratie gesprochen. (2) Die Digitalisierung ermöglicht neue Kommunikations- und Mobilisierungsmuster weitab von den klassischen Formen demokratischer Meinungs- und Willensbildung. (3) Basisdemokratische und partizipative Verhandlungen werden für die Ausgestaltung und Akzeptanz von neuen Technologien immer relevanter. In dieser Einführung entfalten wir diese Herausforderungen und geben einen Überblick über die Beiträge des TATuP-Themas.Technology assessment (TA) was established more than 50 years ago to support democratic opinion forming and decision making. Since then, it has developed and diversified in Western democratic societies. This model has faced a number of challenges in recent years, including: (1) In almost all Western countries, the rise of populist movements has led to talk of a crisis of democracy. (2) The ongoing digitalization enables new patterns of communication and mobilization far beyond traditional forms of democratic opinion forming and decision making. (3) Grassroots and participatory negotiations are becoming more and more relevant for the development and acceptance of new technology. This introduction unfolds these challenges and provides an overview of the contributions to the TATuP special topic

Geschlossen-analytische Modellierung der Längsvermischung von Kühlmittelpfropfen auf dem Weg vom Reaktoreintrittsstutzen zum Kerneintritt in Druckwasserreaktoren

Messungen an der Versuchsanlage ROCOM mit der in Rossendorf entwickelten Gittersensortechnik lieferten auch zeitabhängige mittlere Vermischungen an verschiedenen Modellpositionen. Der Versuch, diese mit Hilfe eines aufgestellten geschlossen-analytischen 1D-Rechenmodells der turbulenten Diffusion in einer stationären und symmetrischen Modellströmung nachzurechnen, erwies sich auch für den Fall einfachster Annahmen und einer Anpassung an nur einen Fluidmassenstrom, der bis auf das 6-fache erhöht wurde, als erfolgreich. Zum Vergleich mit den Messungen und den Ergebnissen aus den analytischen Rechnungen werden auch CFX-4 Simulationen herangezogen, welche eine gute Übereinstimmung aller angewandten Verfahren zur Bestimmung der mittleren Vermischungen an der Modellanlage ROCOM bestätigen. Insbesondere konnten auch in Abhängigkeit von der dimensionslosen Pfropfenlänge der Tracerdosierungen nicht nur die Maxima der mittleren Vermischungsverteilungen berechnet, sondern auch die zu erwartenden Maximalwerte selbst abgeschätzt werden. Eine Anwendung des beschriebenen analytischen Verfahrens und der CFX-4 Simulationen auf prinzipiell beliebige Modelle und Originalkomponenten bei vergleichbaren turbulenten stationären und symmetrischen Strömungen läßt ebenso gute Ergebnisse erwarten

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

Rev Proteins of Human and Simian Immunodeficiency Virus Enhance RNA Encapsidation

The main function attributed to the Rev proteins of immunodeficiency viruses is the shuttling of viral RNAs containing the Rev responsive element (RRE) via the CRM-1 export pathway from the nucleus to the cytoplasm. This restricts expression of structural proteins to the late phase of the lentiviral replication cycle. Using Rev-independent gag-pol expression plasmids of HIV-1 and simian immunodeficiency virus and lentiviral vector constructs, we have observed that HIV-1 and simian immunodeficiency virus Rev enhanced RNA encapsidation 20- to 70-fold, correlating well with the effect of Rev on vector titers. In contrast, cytoplasmic vector RNA levels were only marginally affected by Rev. Binding of Rev to the RRE or to a heterologous RNA element was required for Rev-mediated enhancement of RNA encapsidation. In addition to specific interactions of nucleocapsid with the packaging signal at the 5′ end of the genome, the Rev/RRE system provides a second mechanism contributing to preferential encapsidation of genomic lentiviral RNA