651 research outputs found
Isentropic Equation of State of Two-Flavour QCD in a Quasi-Particle Model
We examine the isentropic QCD equation of state within a quasi-particle model
being adjusted to first principle QCD calculations of two quark flavours. In
particular, we compare with Taylor expansion coefficients of energy and entropy
densities and with the isentropic trajectories describing the hydrodynamical
expansion of a heavy-ion collision fireball.Comment: Aug. 2006. 6pp. Invited talk given at International Workshop on Hot
and Dense Matter in Relativistic Heavy Ion Collisions, Budapest, Hungary,
9-12 Apr 200
Detektion des Kartoffelspindelknollen Viroids mit Hilfe der Loop Mediated Isothermal Amplification
PSTV ist ein hoch infektiöses Viroid, das in Kartoffeln verkleinerte und spindelähnliche Knollen verursacht. Um Ernteverlusten vorzubeugen, ist eine Detektion in frühen Infektionsstadien von großer Bedeutung. Aufgrund ihrer hohen Sensitivität und Spezifität wird die PCR als Standardnachweisverfahren für PSTV verwendet. Nachteilig an dieser Methode sind der apparative Aufwand und die zeitaufwändige Durchführung. Als viel versprechende Alternative konnte der Nachweis von PSTV mit Hilfe der Reverse Transcription Loop Mediated Isothermal Amplification (RT-LAMP) gezeigt werden. Hierbei handelt es sich um eine einfache und schnelle Methode, für die wenig aufwändige Laborausrüstung benötigt wird. Dabei ermöglichte eine an den Amplifikationsprozess gekoppelte Fluoreszenzreaktion die Detektion von Produkten direkt nach der Nachweisreaktion mit dem bloßen Auge (bzw. unter UV-Licht). Die Ergebnisse konnten mit Hilfe einer Real Time Detektion des auftretenden Fluoreszenzsignals bestätigt werden.PSTV is a highly infectious viroid which leads to small and spindle shaped tubers in potatoes. The detection at an early stage of infection is important to minimize loss of harvest. Normally PCR is used for the detection of PSTV, because of its high sensitivity and specificity. Disadvantages of this method are the requirement of sophisticated equipment and the time consuming process. As a promising alternative, the detection of PSTV with the reverse transcription loop mediated isothermal amplification (RT-LAMP) was shown. LAMP is a very fast and simple detection method requiring only standard laboratory equipment. A fluorescence reaction, coupled to the amplification process, allowed the detection of amplification products directly after the reaction with the naked eye (or under UV light, respectively). Real time detection of the occurring fluorescence signal was possible and confirmed the obtained results
Erweiterung des ProC-B-Paradigmas zur Abbildung entscheidungsrelevanter Kosten und zur Kostenverrechnung
A procedure to derive partial safety factors in textile-reinforced concrete members
In the last decades, modern technological and research developments of textile-reinforced concrete have led to extensive applications in building and civil engineering structures all over the world. Examples of textile-reinforced concrete can be found in retrofitting of existing buildings, facade slabs or bridges. Despite its potential, the widespread use of textile-reinforced concrete remains still limited. This is partly explained by the lack of a consistent design framework since conventional design methods used for other materials (e.g., steel reinforced concrete) cannot be directly applicable to textile-reinforced concrete. Thus, procedures to derive partial safety factors for textile-reinforced concrete would be a major step forward towards a regular procedure for the design of structural members made of this material.This paper offers a general procedure to determine safety factors. The approach is illustrated with a bending design example of a textile-reinforced concrete facade slab. The example is calculated in a recently developed software package for structural reliability analysis built in the statistical programming language R. For the derivation of safety factors, initial data is required, which can be obtained from experimental or numerical tests or from literature. The paper includes the basics of data evaluation as well as the statistical characterisation of data extracted from literature
Statistical characterisation of reinforcement properties for textile-reinforced concrete: a novel approach
The potential of textile-reinforced concrete is broad: it can be used in new structures and in the retrofitting of existing structural components. Designing textile-reinforced concrete requires knowledge about the mechanical properties of different textile types. To this, a standardised tensile test for fibre strands was used. The test aims to statistically characterise two material properties needed in design: ultimate tensile strength and the modulus of elasticity. To this, the influence of length and number of fibre strands were evaluated. The results show that the ultimate tensile strength can be statistically modelled by a Gumbel distribution and the modulus of elasticity can be characterised by a Normal distribution. These findings can be used to derive appropriate partial safety factors for the design value of tensile strength using probabilistic methods, or to directly determine the failure probability of textile-reinforced concrete components
"Design your Education". Zur Bedeutung einer hochschuldidaktischen Fortbildung fĂĽr Lehrerbildner:innen fĂĽr das Lehren und Lernen in einer Hochschullernwerkstatt
Im Zuge der Implementation des Hochschullernwerkstattansatzes in das Lehramtsstudium der Universität Erfurt zeigte sich, dass sowohl fachkulturelle Spezifika als auch individuelle Überzeugungen und Werthaltungen der Lehrerbildner:innen das hochschuldidaktische Handeln beeinflussen und zu Unterschieden in der Ausgestaltung der Lehre führen. Für eine empirisch fundierte Weiterentwicklung einer Didaktik der Lehrer:innenbildung sind deshalb neben curricularen Aspekten und Modellentwicklungen auch die Kompetenzen der Lehrerbildner:innen selbst in den Blick zu nehmen und zu fördern. Dieser Zielsetzung ist eine dreisemestrige Fortbildung verpflichtet, die in diesem Beitrag konzeptionell vorgestellt und auf der Grundlage von Daten aus der evaluativen Begleitforschung in ihrer Praktikabilität beurteilt wird. Ergänzend werden Einblicke in das Lernwerkstattseminar „Ästhetische Zugänge zur Demokratiebildung im Sachunterricht“ gegeben, das eine Lehrende innerhalb der Fortbildung weiterentwickelte. (DIPF/Orig.
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Lipid–Polymer Hybrid Nanoparticles for mRNA Delivery to Dendritic Cells: Impact of Lipid Composition on Performance in Different Media
To combine the excellent transfection properties of lipids with the high stability of polymeric nanoparticles, we designed a hybrid system with a polymeric core surrounded by a shell of different lipids. The aim is to use this technology for skin vaccination purposes where the transfection of dendritic cells is crucial. Based on a carrier made of PLGA and the positively charged lipid DOTMA, we prepared a panel of nanocarriers with increasing amounts of the zwitterionic phospholipid DOPE in the lipid layer to improve their cell tolerability. We selected a nomenclature accordingly with numbers in brackets to represent the used mol% of DOPE and DOTMA in the lipid layer, respectively. We loaded mRNA onto the surface and assessed the mRNA binding efficacy and the degree of protection against RNases. We investigated the influence of the lipid composition on the toxicity, uptake and transfection in the dendritic cell line DC 2.4 challenging the formulations with different medium supplements like fetal calf serum (FCS) and salts. After selecting the most promising candidate, we performed an immune stimulation assay with primary mouse derived dendritic cells. The experiments showed that all tested lipid–polymer nanoparticles (LPNs) have comparable hydrodynamic parameters with sizes between 200 and 250 nm and are able to bind mRNA electrostatically due to their positive zetapotential (20–40 mV for most formulations). The more of DOPE we add, the more free mRNA we find and the better the cellular uptake reaching approx. 100% for LPN(60/40)–LPN(90/10). This applies for all tested formulations leading to LPN(70/30) with the best performance, in terms of 67% of live cells with protein expression. In that case, the supplements of the medium did not influence the transfection efficacy (56% vs. 67% (suppl. medium) for live cells and 63% vs. 71% in total population). We finally confirmed this finding using mouse derived primary immune cells. We can conclude that a certain amount of DOTMA in the lipid coating of the polymer core is essential for complexation of the mRNA, but the zwitterionic phospholipid DOPE is also important for the particles’ performance in supplemented media
A novel echocardiographic-based classification for the prediction of peri-device leakage following left atrial appendage occluder implantation
(1) Background: The assessment of residual peri-device leakages (PDL) after left atrial appendage occlusion (LAAO) remains crucial for post-procedural management. Our study aimed to verify a novel echocardiographic classification for the prediction of PDL. (2) Methods: Echocardiographic data of 72 patients who underwent percutaneous LAAO were evaluated. All echo images were analyzed by two independent investigators using standard analysis software (Image-Arena IA-4.6.4.44 by TomTec ® , Munich, Germany). A total number of 127 studies was evaluated. Forty-four patients had baseline studies, at 45 days and at 6 months post-implantation. We propose a morphological classification of LAA devices based on the amount of echodensity inside the devices into three types: type A showing complete homogenous thrombosis, type B incompletely thrombosed device with inhomogeneous echo-free space 50% of device in various planes, which we called the “ice-cream cone” sign. Each type was matched to the degree of PDL and clinical outcome parameters. (3) Results: Patients with type C had the highest percentage of PDL at 45 days follow-up (type A: 24%, type B: 31%, type C 100% PDL, p < 0.001) and at 6 months follow-up (type A: 7%, type B: 33%, type C 100% PDL, p < 0.001). Notably, device size in patients with PDL was larger than that in patients without PDL at 6 months follow-up (25.6 ± 3.5 mm vs. 28.7 ± 3.4 mm, p = 0.004). Device size in patients with type C appearance was the largest of the three types (type A: 25.9 ± 3.6 mm, type B: 25.8 ± 3.4 mm, type C 29.8 ± 3.0 mm, type A vs. C; p = 0.019; type B vs. C, p = 0.007). (4) Conclusions: In conclusion, PDL are common post-LAAO, and their frequency is underestimated and under-recognized. PDL are much more common in patients with larger LAA ostial sizes and likely lower longitudinal compression. Type C appearance of the LAAO devices (“ice-cream cone sign”) has a high positive predictive value for PDL. Further studies are needed for better delineation of the clinical importance of this proposed classification
Lipid-Polymer Hybrid Nanoparticles for mRNA Delivery to Dendritic Cells : Impact of Lipid Composition on Performance in Different Media
To combine the excellent transfection properties of lipids with the high stability of polymeric
nanoparticles, we designed a hybrid system with a polymeric core surrounded by a shell of different
lipids. The aim is to use this technology for skin vaccination purposes where the transfection of
dendritic cells is crucial. Based on a carrier made of PLGA and the positively charged lipid DOTMA,
we prepared a panel of nanocarriers with increasing amounts of the zwitterionic phospholipid
DOPE in the lipid layer to improve their cell tolerability. We selected a nomenclature accordingly
with numbers in brackets to represent the used mol% of DOPE and DOTMA in the lipid layer,
respectively. We loaded mRNA onto the surface and assessed the mRNA binding efficacy and the
degree of protection against RNases. We investigated the influence of the lipid composition on
the toxicity, uptake and transfection in the dendritic cell line DC 2.4 challenging the formulations
with different medium supplements like fetal calf serum (FCS) and salts. After selecting the most
promising candidate, we performed an immune stimulation assay with primary mouse derived
dendritic cells. The experiments showed that all tested lipid–polymer nanoparticles (LPNs) have
comparable hydrodynamic parameters with sizes between 200 and 250 nm and are able to bind
mRNA electrostatically due to their positive zetapotential (20–40 mV for most formulations). The
more of DOPE we add, the more free mRNA we find and the better the cellular uptake reaching
approx. 100% for LPN(60/40)–LPN(90/10). This applies for all tested formulations leading to
LPN(70/30) with the best performance, in terms of 67% of live cells with protein expression. In
that case, the supplements of the medium did not influence the transfection efficacy (56% vs. 67%
(suppl. medium) for live cells and 63% vs. 71% in total population). We finally confirmed this finding
using mouse derived primary immune cells. We can conclude that a certain amount of DOTMA in
the lipid coating of the polymer core is essential for complexation of the mRNA, but the zwitterionic
phospholipid DOPE is also important for the particles’ performance in supplemented media
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