102 research outputs found
in situ joining of unidirectional tapes on long fiber reinforced thermoplastic structures by thermoplastic automated fiber placement for scientific sounding rocket applications
Abstract Automated Fiber Placement allows the automated lay-up of tailored laminates in aerospace quality. For thermoplastic matrix materials, the use of closed-loop temperature control enables an in situ consolidation. This makes autoclave curing superfluous and increases the overall process efficiency. Scientific sounding rockets typically consist of several aluminum modules carrying the scientific payload. The design of a module includes a cylindrical outer shell and two load input rings with a defined assembly interface. Reducing the structural weight would allow higher payloads, higher apogees or reduced fuel consumption. A new manufacturing concept using the Thermoplastic Automated Fiber Placement (TP-AFP) process was developed to manufacture a lightweight composite module. This paper presents the developed concept and focuses on the characterization of an in situ joint of TP-AFP tapes on a long fiber reinforced thermoplastic (LFT) structure. This represents the joint of the cylindrical shell on the load input rings of the rocket module. The joint was characterized with single lap shear tests for two different sample extraction areas at room temperature and at elevated temperature on pre-treated and untreated LFT surface. The variations did not show significant effects on the resulting shear strength. The results were considered for the design of the composite module allowing a weight reduction of more than 40 % compared to the aluminum modules. The new module proved its airworthiness as part of the sounding rocket mission REXUS-23 in March 2019. Beyond sounding rockets, the concept of in situ bonded TP-AFP tapes on complex LFT structures has many potential applications within aerospace but also automotive structures
Junctional adhesion molecule (JAM)-C deficient C57BL/6 mice develop a severe hydrocephalus
The junctional adhesion molecule (JAM)-C is a widely expressed adhesion molecule regulating cell adhesion, cell polarity and inflammation. JAM-C expression and function in the central nervous system (CNS) has been poorly characterized to date. Here we show that JAM-C−/− mice backcrossed onto the C57BL/6 genetic background developed a severe hydrocephalus. An in depth immunohistochemical study revealed specific immunostaining for JAM-C in vascular endothelial cells in the CNS parenchyma, the meninges and in the choroid plexus of healthy C57BL/6 mice. Additional JAM-C immunostaining was detected on ependymal cells lining the ventricles and on choroid plexus epithelial cells. Despite the presence of hemorrhages in the brains of JAM-C−/− mice, our study demonstrates that development of the hydrocephalus was not due to a vascular function of JAM-C as endothelial re-expression of JAM-C failed to rescue the hydrocephalus phenotype of JAM-C−/− C57BL/6 mice. Evaluation of cerebrospinal fluid (CSF) circulation within the ventricular system of JAM-C−/− mice excluded occlusion of the cerebral aqueduct as the cause of hydrocephalus development but showed the acquisition of a block or reduction of CSF drainage from the lateral to the 3rd ventricle in JAM-C−/− C57BL/6 mice. Taken together, our study suggests that JAM-C−/− C57BL/6 mice model the important role for JAM-C in brain development and CSF homeostasis as recently observed in humans with a loss-of-function mutation in JAM-C
Temperature sensitivity of soil organic carbon respiration along a forested elevation gradient in the Rwenzori Mountains, Uganda
Comparability of neuraminidase inhibition antibody titers measured by enzyme-linked lectin assay (ELLA) for the analysis of influenza vaccine immunogenicity
AbstractNeuraminidase-inhibition (NI) antibody titers can be used to evaluate the immunogenicity of inactivated influenza vaccines and have provided evidence of serologic cross-reactivity between seasonal and pandemic H1N1 viruses. The traditional thiobarbituric acid assay is impractical for large serologic analyses, and therefore many laboratories use an enzyme-linked lectin assay (ELLA) to determine serum NI antibody titers. The comparability of ELLA NI antibody titers when measured in different laboratories was unknown. Here we report a study conducted through the Consortium for the Standardisation of Influenza SeroEpidemiology (CONSISE) to evaluate the variability of the ELLA. NI antibody titers of a set of 12 samples were measured against both N1 and N2 neuraminidase antigens in 3 independent assays by each of 23 laboratories. For a sample repeated in the same assay, ≥96% of N1 and N2 assays had less than a 4-fold difference in titer. Comparison of the titers measured in assays conducted on 3 different days in the same laboratory showed that a four-fold difference in titer was uncommon. Titers of the same sera measured in different laboratories spanned 3 to 6 two-fold dilutions (i.e., 8–64 fold difference in titer), with an average percent geometric coefficient of variation (%GCV) of 112 and 82% against N1 and N2 antigens, respectively. The difference in titer as indicated by fold range and %GCV was improved by normalizing the NI titers to a standard that was included in each assay. This study identified background signal and the amount of antigen in the assay as critical factors that influence titer, providing important information toward development of a consensus ELLA protocol
Gauged Inflation
We propose a model for cosmic inflation which is based on an effective
description of strongly interacting, nonsupersymmetric matter within the
framework of dynamical Abelian projection and centerization. The underlying
gauge symmetry is assumed to be with . Appealing to a
thermodynamical treatment, the ground-state structure of the model is
classically determined by a potential for the inflaton field (dynamical
monopole condensate) which allows for nontrivially BPS saturated and thereby
stable solutions. For this leads to decoupling of gravity from the
inflaton dynamics. The ground state dynamics implies a heat capacity for the
vacuum leading to inflation for temperatures comparable to the mass scale
of the potential. The dynamics has an attractor property. In contrast to the
usual slow-roll paradigm we have during inflation. As a consequence,
density perturbations generated from the inflaton are irrelevant for the
formation of large-scale structure, and the model has to be supplemented with
an inflaton independent mechanism for the generation of spatial curvature
perturbations. Within a small fraction of the Hubble time inflation is
terminated by a transition of the theory to its center symmetric phase. The
spontaneously broken symmetry stabilizes relic vector bosons in the
epochs following inflation. These heavy relics contribute to the cold dark
matter of the universe and potentially originate the UHECRs beyond the GZK
bound.Comment: 23 pages, 4 figures, subsection added, revision of text, to app. in
PR
DGK and DZHK position paper on genome editing: basic science applications and future perspective
For a long time, gene editing had been a scientific concept, which was limited to a few applications. With recent developments, following the discovery of TALEN zinc-finger endonucleases and in particular the CRISPR/Cas system, gene editing has become a technique applicable in most laboratories. The current gain- and loss-of function models in basic science are revolutionary as they allow unbiased screens of unprecedented depth and complexity and rapid development of transgenic animals. Modifications of CRISPR/Cas have been developed to precisely interrogate epigenetic regulation or to visualize DNA complexes. Moreover, gene editing as a clinical treatment option is rapidly developing with first trials on the way. This article reviews the most recent progress in the field, covering expert opinions gathered during joint conferences on genome editing of the German Cardiac Society (DGK) and the German Center for Cardiovascular Research (DZHK). Particularly focusing on the translational aspect and the combination of cellular and animal applications, the authors aim to provide direction for the development of the field and the most frequent applications with their problems
Temporal Pattern of ICAM-I Mediated Regulatory T Cell Recruitment to Sites of Inflammation in Adoptive Transfer Model of Multiple Sclerosis
Migration of immune cells to the target organ plays a key role in autoimmune disorders like multiple sclerosis (MS). However, the exact underlying mechanisms of this active process during autoimmune lesion pathogenesis remain elusive. To test if pro-inflammatory and regulatory T cells migrate via a similar molecular mechanism, we analyzed the expression of different adhesion molecules, as well as the composition of infiltrating T cells in an in vivo model of MS, adoptive transfer experimental autoimmune encephalomyelitis in rats. We found that the upregulation of ICAM-I and VCAM-I parallels the development of clinical disease onset, but persists on elevated levels also in the phase of clinical remission. However, the composition of infiltrating T cells found in the developing versus resolving lesion phase changed over time, containing increased numbers of regulatory T cells (FoxP3) only in the phase of clinical remission. In order to test the relevance of the expression of cell adhesion molecules, animals were treated with purified antibodies to ICAM-I and VCAM-I either in the phase of active disease or in early remission. Treatment with a blocking ICAM-I antibody in the phase of disease progression led to a milder disease course. However, administration during early clinical remission aggravates clinical symptoms. Treatment with anti-VCAM-I at different timepoints had no significant effect on the disease course. In summary, our results indicate that adhesion molecules are not only important for capture and migration of pro-inflammatory T cells into the central nervous system, but also permit access of anti-inflammatory cells, such as regulatory T cells. Therefore it is likely to assume that intervention at the blood brain barrier is time dependent and could result in different therapeutic outcomes depending on the phase of CNS lesion development
Detector Systems Engineering for Extremely Large Instruments
The scientific detector systems for the ESO ELT first-light instruments,
HARMONI, MICADO, and METIS, together will require 27 science detectors:
seventeen 2.5 m cutoff H4RG-15 detectors, four 4K x 4K 231-84 CCDs, five
5.3 m cutoff H2RG detectors, and one 13.5 m cutoff GEOSNAP detector.
This challenging program of scientific detector system development covers
everything from designing and producing state-of-the-art detector control and
readout electronics, to developing new detector characterization techniques in
the lab, to performance modeling and final system verification. We report
briefly on the current design of these detector systems and developments
underway to meet the challenging scientific performance goals of the ELT
instruments.Comment: Proceedings of the SPIE Astronomical Telescopes and Instrumentation
Conference 202
Operator Product Expansion and Quark-Hadron Duality: Facts and Riddles
We review the status of the practical operator product expansion (OPE), when
applied to two-point correlators of QCD currents which interpolate to mesonic
resonances, in view of the violations of local quark-hadron duality. Covered
topics are: a mini-review of mesonic QCD sum rules in vacuum, at finite
temperature, or at finite baryon density, a comparison of model calculations of
current-current correlation functions in 2D and 4D with the OPE expression, a
discussion of meson distribution amplitudes in the light of nonperturbatively
nonlocal modifications of the OPE, and a reorganization of the OPE which
(partially) resums powers of covariant derivatives.Comment: now 68 pages, 29 figures (1 figure added), habilitation thesis, mild
restructuring, typos corrected, about 30 references and corresponding text
added, version to be published in Prog. Part. Nucl. Phy
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