Qubesat for Aerothermodynamic Research and Measurement on AblatioN

International audienceThe preliminary design of the QARMAN re-entry CubeSat developed by the von Karman Institute is presented in this paper from de-orbiting to payload choices. It represents an ideal cost-efficient platform for re-entry flight test and validation of thermal protection system (TPS) materials with a demonstration flight scheduled for June 2015. The CubeSat comprises a standard double-unit platform with sensors for atmospheric research and a functional unit for essential satellite operations. A third unit accommodating an ablative heat shield is added to protect the vehicle against the extreme aerothermal conditions of the re-entry. The challenging aspect of the project lies on the constraining mass and form factor from the CubeSat standard, 3kg and 34x10x10 cm 3. Finally, the preliminary design of the vehicle results in a payload of 400 g collecting data all along the re-entry trajectory including the maximal heat flux conditions

A one-step PCR assay for the detection of pathogenic Y. enterocolitica in artificially contaminated fecal samples and lymphoid tissue

In order to specifically detect pathogenic, plasmid bearing Yersinia enterocolitica, we have developed a polymerase chain reaction (PCR) assay based on the plasmid located gene yopT. A substantial number of mismatches within the yopT coding sequence between Y. enterocolitca, Y. pseudotuberculosis, and Y. pestis was used to generate a primer pair that exclusively detects pathogenic Y. enteroco/itica with a high sensitivity and specificity. When this PCR assay was used for the detection of pathogenic Y. enterocolilica cells in artificially inoculated fecal samples and lymphoid tissue of pigs, levels as low as 102 cells per gram feces and 101 cells per gram lymphoid tissue could be detected if an 24 h pre-enrichment in Luria Bertani-Bouillon was performed prior to the PCR

Influence of long-time transportation stress on re-activation of Salmonella Typhimurium DT104 in experimentally infected pigs

In this study a Salmonella Typhimurium infection model in swine was used in order to investigate the influence of pre-mortal stress induced by long time period transportation on the re-activation of Salmonella in experimentally infected pigs. Salmonella free pigs were exposed to a highly virulent strain of Salmonella Typhimurium DT I 04 by direct intragastrical administration. Clinical parameters were monitored and the shedding rate in faeces was qualitatively and quantitatively determined by standard bacteriological procedures for 2 1 days. The distribution of the challenge organism in 14 different internal organs of transported and nontransported animals was determined. All infected animals developed clinical signs of salmonellosis 12 to 24 hours post infection. About 88 to 100 % of the fecal samples were culture-positive up to post exposure day 6, and then varied from 71 to 92 % until slaughter, respectively. At necropsy S. typhimurium was recovered most frequently from caecum and ileocolic lymph nodes (83 %), colon (79 %), pa latine tonsils (71 %) and mandibular lymph nodes (62.5 %). A negative impact of transportation stress on the shedding rate and the genera l condition of the animals was observed

Improvement of an invA-based PCR for the specific detection of Salmonella typhimurium in organs of pigs

The aim of this study was to investigate the suitability of the invA-based polymerase chain reaction (PCR) assay for the specific detection of Salmonella in organs of experimentally infected pigs and to compare these results to classical bacterial culture. While the PCR conditions specified in the Deutsche Industrie Norm , DIN I 0135 (§ 35 LMBG, 1999), revealed various unspecific amplification products, modifications of the PCR conditions allowed the specific amplification of the invA fragment from inner organs. The modified PCR assay correlates excellently with cultivation results (as required by DIN Norm 6579) and enables the detection of Salmonella within 48 hours with equal sensitivity compared to routine cultivation

Blackout analysis of small cone-shaped reentry vehicles

The high temperatures associated with the hypersonic reentry process lead to an increase in the collisions between molecules, which may result in the disruption of the electronic structure, producing free electrons and ions. This production of free electrons and ions creates a plasma or ionized flowfield around the vehicle that is known to degrade the quality of radio-wave signal propagation, leading to a loss of communication or "blackout." This study involves performing hypersonic computational fluid dynamics simulations in the commercial software CFD++ with a bluntnosed cone geometry at different flight conditions to predict how and when ground communication can be achieved to aid in the design of an alert transmitter, which is an extension of aircraft collision-avoidance system technology. Computational results show that a small blunt-nosed cone geometry has decreased ionization regions as the cone angle decreases due to a shifting of the reaction zone further downstream. As a result, higher freestream velocities have less of an impact in determining the location for an antenna, and communicating along the stagnation line is seen to be independent of cone angle

Biomarkers for Non-Invasive Stratification of Coronary Artery Disease and Prognostic Impact on Long-Term Survival in Patients with Stable Coronary Heart Disease

Knowledge about cardiac and inflammatory biomarkers in patients with stable coronary artery disease (CAD) is limited. To address this, we analyzed 3072 patients (36% female) with a median follow-up of 10 years in the Leipzig LIFE Heart Study with suspected CAD with coronary angiography. Selected biomarkers included troponin T (hsTNT), N-terminal pro B-type natriuretic peptide (NT-proBNP), copeptin, C-reactive protein (hsCRP), and interleukin-6 (IL-6). Patients were stratified by CAD severity: CAD0 (no sclerosis), CAD1 (non-obstructive, i.e., stenosis < 50%), and CAD2 (one stenosis 50%). Group comparison (GC) included GC1: CAD0 + 1 vs. CAD2; GC2: CAD0 vs. CAD1 + 2. CAD0, CAD1, and CAD2 were apparent in 1271, 631, and 1170 patients, respectively. Adjusted for classical risk factors, hs-cTnT, NT-proBNP, and IL-6 differed significantly in both GC and hsCRP only in GC2. After multivariate analysis, hs-cTnT, NT-proBNP, and IL-6 remained significant in GC1. In GC2, hs-cTnT (p < 0.001) and copeptin (p = 0.014) reached significance. Ten-year survival in groups CAD0, CAD1, and CAD2 was 88.3%, 77.3%, and 72.4%. Incorporation of hs-cTnT, NT-proBNP, copeptin, and IL-6 improved risk prediction (p < 0.001). The studied cardiac and inflammatory biomarkers enable fast and precise non-invasive identification of mortality risk in CAD patients, allowing the tailoring of primary and secondary CAD prevention

Lignin oxidation products in soil, dripwater and speleothems from four different sites in New Zealand

Lignin oxidation products (LOPs) are widely used as vegetation proxies in climate archives, such as sediment and peat cores. The total LOP concentration, Σ8, provides information on the abundance of vegetation, while the ratios C/V and S/V of the different LOP groups also provide information on the type of vegetation. Recently, LOP analysis has been successfully applied to speleothem archives. However, there are many open questions concerning the transport and microbial degradation of LOPs on their way from the soil into the cave system. These processes could potentially alter the original source-dependent LOP signals, in particular the C/V and S/V ratios, and thus complicate their interpretation in terms of past vegetation changes. We analyzed LOPs in leaf litter and different soil horizons as well as dripwater and flowstone samples from four different cave sites from different vegetation zones in New Zealand using ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry. We test whether the original source-dependent LOP signal of the overlying vegetation is preserved and can be recovered from flowstone samples and investigate how the signal is altered by the transport from the soil to the cave. The LOP concentrations range from mg g−1 in the soil to ng g−1 in the flowstones. Our results demonstrate that, from the soil to the flowstone, the C/V and S/V ratios both increase, while the total lignin content, Σ8, strongly decreases. This shows that the LOP signal is strongly influenced by both transport and degradation processes. Nevertheless, the relative LOP signal from the overlying soil at the different cave sites is preserved in the flowstone. We emphasize that for the interpretation of C/V and S/V ratios in terms of past vegetation changes, it is important to compare only samples of the same type (e.g., speleothem, dripwater or soil) and to evaluate only relative variations