Inorganic–Organic Hybrid Nanoprobe for NIR‐Excited Imaging of Hydrogen Sulfide in Cell Cultures and Inflammation in a Mouse Model

Hydrogen sulfide (H₂S) is an important gaseous signaling agent mediated by many physiological processes and diseases. In order to explore its role in biological signaling, much effort has been focused on developing organic fluorescent probes to image H₂S. However, these downconversion H₂S probes are impractical for bio‐imaging beyond a certain depth because of the short tissue penetration of UV/visible light (as an excitation source). In most circumstance, these probes are also not suitable for long‐term assay due to photo‐bleaching. Herein, a new design to detect H₂S based on the coumarin‐hemicyanine (CHC1)‐modified upconversion nanophosphors is reported. This inorganic–organic integrated nanoprobe is demonstrated to display a fast response time with a large ratiometric upconversion luminescence (UCL) enhancement, and extraordinary photo‐stability. CHC1‐UCNPs not only can be used for ratiometric UCL monitoring of pseudo‐enzymatic H₂S production in living cells, but can also be used to identify the risk of endotoxic shock through ratiometric UCL imaging of tissue and measurement of endogenous H₂S levels in plasma. The first ratiometric UCL H₂S nanoprobe reported here may be further developed as the next‐generation diagnostic tool for the detection of inflammatory‐related diseases.     

Shear tests on full scale storey‐height specimens constructed with thermally insulating clay unit masonry with thin‐layer mortar

The paper presents results of a series of 6 in‐plane shear tests on storey‐height clay unit masonry panels [1] with thin‐layer mortar, carried out in addition to previous test campaigns [2], [3], and [4]. The walls were constructed with unfilled thermally insulating clay units with a thermal conductivity of λ = 0.09 W/(m · K). The current design rules for clay unit masonry according to DIN EN 1996‐1‐1/NA [5] are conservative compared to the presented test results for thermally insulating clay unit masonry.     

CubiST++: Evaluating Ad-Hoc CUBE Queries Using Statistics Trees

We report on a new, efficient encoding for the data cube, which results in a drastic speed-up of OLAP queries that aggregate along any combination of dimensions over numerical and categorical attributes. We are focusing on a class of queries called cube queries, which return aggregated values rather than sets of tuples. Our approach, termed CubiST⁺⁺ (Cubing with Statistics Trees Plus Families), represents a drastic departure from existing relational (ROLAP) and multi-dimensional (MOLAP) approaches in that it does not use the view lattice to compute and materialize new views from existing views in some heuristic fashion. Instead, CubiST⁺⁺ encodes all possible aggregate views in the leaves of a new data structure called statistics tree (ST) during a one-time scan of the detailed data. In order to optimize the queries involving constraints on hierarchy levels of the underlying dimensions, we select andmaterialize a family of candidate trees, which represent superviews over the different hierarchical levels of the dimensions. Given a query, our query evaluation algorithm selects the smallest tree in the family, which can provide the answer. Extensive evaluations of our prototype implementation have demonstrated its superior run-time performance and scalability when compared with existing MOLAP and ROLAP systems.     

A Completeness Proof for Bisimulation in the pi-calculus Using Isabelle

We use the interactive theorem prover Isabelle to prove that the algebraic axiomatization of bisimulation equivalence in the pi-calculus is sound and complete. This is the first proof of its kind to be wholly machine checked. Although the result has been known for some time the proof had parts which needed careful attention to detail to become completely formal. It is not that the result was ever in doubt; rather, our contribution lies in the methodology to prove completeness and get absolute certainty that the proof is correct, while at the same time following the intuitive lines of reasoning of the original proof. Completeness of axiomatizations is relevant for many variants of the calculus, so our method has applications beyond this single result. We build on our previous effort of implementing a framework for the pi-calculus in Isabelle using the nominal data type package, and strengthen our claim that this framework is well suited to represent the theory of the pi-calculus, especially in the smooth treatment of bound names.     

Norepinephrine Inhibits Lipopolysaccharide-Stimulated TNF-α but Not Oxylipin Induction in n-3/n-6 PUFA-Enriched Cultures of Circumventricular Organs

Sensory circumventricular organs (sCVOs) are pivotal brain structures involved in immune-to-brain communication with a leaky blood–brain barrier that detect circulating mediators such as lipopolysaccharide (LPS). Here, we aimed to investigate the potential of sCVOs to produce n-3 and n-6 oxylipins after LPS-stimulation. Moreover, we investigated if norepinephrine (NE) co-treatment can alter cytokine- and oxylipin-release. Thus, we stimulated rat primary neuroglial sCVO cultures under n-3- or n-6-enriched conditions with LPS or saline combined with NE or vehicle. Supernatants were assessed for cytokines by bioassays and oxylipins by HPLC-MS/MS. Expression of signaling pathways and enzymes were analyzed by RT-PCR. Tumor necrosis factor (TNF)α bioactivity and signaling, IL-10 expression, and cyclooxygenase (COX)2 were increased, epoxide hydroxylase (Ephx)2 was reduced, and lipoxygenase 15-(LOX) was not changed by LPS stimulation. Moreover, LPS induced increased levels of several n-6-derived oxylipins, including the COX-2 metabolite 15d-prostaglandin-J2 or the Ephx2 metabolite 14,15-DHET. For n-3-derived oxylipins, some were down- and some were upregulated, including 15-LOX-derived neuroprotectin D1 and 18-HEPE, known for their anti-inflammatory potential. While the LPS-induced increase in TNFα levels was significantly reduced by NE, oxylipins were not significantly altered by NE or changes in TNFα levels. In conclusion, LPS-induced oxylipins may play an important functional role in sCVOs for immune-to-brain communication.     

Reporting Leaders and Followers among Trajectories of Moving Point Objects

Widespread availability of location aware devices (such as GPS receivers) promotes capture of detailed movement trajectories of people, animals, vehicles and other moving objects, opening new options for a better understanding of the processes involved. In this paper we investigate spatio-temporal movement patterns in large tracking data sets. We present a natural definition of the pattern ‘one object is leading others’, which is based on behavioural patterns discussed in the behavioural ecology literature. Such leadership patterns can be characterised by a minimum time length for which they have to exist and by a minimum number of entities involved in the pattern. Furthermore, we distinguish two models (discrete and continuous) of the time axis for which patterns can start and end. For all variants of these leadership patterns, we describe algorithms for their detection, given the trajectories of a group of moving entities. A theoretical analysis as well as experiments show that these algorithms efficiently report leadership patterns.

Lorentzian-Corrected Apparent Exchange-Dependent Relaxation (LAREX) Ω-Plot Analysis—An Adaptation for qCEST in a Multi-Pool System: Comprehensive In Silico,In Situ,and In Vivo Studies

Based on in silico, in situ, and in vivo studies, this study aims to develop a new method for the quantitative chemical exchange saturation transfer (qCEST) technique considering multi-pool systems. To this end, we extended the state-of-the-art apparent exchange-dependent relaxation (AREX) method with a Lorentzian correction (LAREX). We then validated this new method with in situ and in vivo experiments on human intervertebral discs (IVDs) using the Kendall-Tau correlation coefficient. In the in silico experiments, we observed significant deviations of the AREX method as a function of the underlying exchange rate (k_ba) and fractional concentration (f_b) compared to the ground truth due to the influence of other exchange pools. In comparison to AREX, the LAREX-based Ω-plot approach yielded a substantial improvement. In the subsequent in situ and in vivo experiments on human IVDs, no correlation to the histological reference standard or Pfirrmann classification could be found for the f_b (in situ: τ = −0.17 p = 0.51; in vivo: τ = 0.13 p = 0.30) and k_ba (in situ: τ = 0.042 p = 0.87; in vivo: τ = −0.26 p = 0.04) of Glycosaminoglycan (GAG) with AREX. In contrast, the influence of interfering pools could be corrected by LAREX, and a moderate to strong correlation was observed for the fractional concentration of GAG for both in situ (τ = −0.71 p = 0.005) and in vivo (τ = −0.49 p < 0.001) experiments. The study presented here is the first to introduce a new qCEST method that enables qCEST imaging in systems with multiple proton pools.     

Electronic Nose Functionality for Breath Gas Analysis during Parabolic Flight

The presence of humans in space represents a constant threat for their health and safety. Environmental factors such as living in a closed confinement, as well as exposure to microgravity and radiation, are associated with significant changes in bone metabolism, muscular atrophy, and altered immune response, which has impacts on human performance and possibly results in severe illness. Thus, maintaining and monitoring of crew health status has the highest priority to ensure whole mission success. With manned deep space missions to moon or mars appearing at the horizon where short-term repatriation back to earth is impossible the availability of appropriate diagnostic platforms for crew health status is urgently needed. In response to this need, the present experiment evaluated the functionality and practicability of a metal oxide based sensor system (eNose) together with a newly developed breath gas collecting device under the condition of altering acceleration. Parabolic flights were performed with an Airbus A300 ZeroG at Bordeaux, France. Ambient air and exhaled breath of five healthy volunteers was analyzed during steady state flight and parabolic flight maneuvres. All volunteers completed the study, the breath gas collecting device valves worked appropriately, and breathing through the collecting device was easy and did not induce discomfort. During breath gas measurements, significant changes in metal oxide sensors, mainly sensitive to aromatic and sulphur containing compounds, were observed with alternating conditions of acceleration. Similarly, metal oxide sensors showed significant changes in all sensors during ambient air measurements. The eNose as well as the newly developed breath gas collecting device, showed appropriate functionality and practicability during alternating conditions of acceleration which is a prerequisite for the intended use of the eNose aboard the International Space Station (ISS) for breath gas analysis and crew health status monitoring. The observed changes in breath gas composition are most likely associated with changes in ambient air volatile organic and inorganic compound composition and require further evaluation.     

High‐Temperature Creep Behavior of SiOC Glass‐Ceramics: Influence of Network Carbon Versus Segregated Carbon

Three silicon oxycarbide samples with different carbon contents are analyzed in the present study with respect to their high‐temperature creep behavior. The tests were performed in compression at 1100°C, 1200°C, and 1300°C; in this temperature range the mechanism of creep relies on viscoelastic flow within the samples and has been modeled with the Jeffreys viscoelastic model. After the release of the applied mechanical stress, a viscoelastic recovery behavior was observed in all samples. The creep behavior of the investigated samples indicates two rheological contributions in SiOC: (i) a high viscous answer, coming from the silica‐rich network, and (ii) an elastic response from the segregated carbon phase within the samples. Furthermore, two distinct effects of the carbon phase on the HT creep behavior of SiOC were identified and are discussed in the present paper: the effect of the carbon presence within the SiOC network (the “carbidic” carbon), which induces a significant increase in the viscosity and a strong decrease in the activation energy for creep, as compared to vitreous silica; and the influence of the segregated carbon phase (the “free” carbon), which has been shown to affect the viscosity and the activation energy of creep and dominates the creep behavior in phase‐separated silicon oxycarbides.