Mortar and brick materials treated with hydrophobic injection media, studied by environmental scanning electron microscopy

The following article presents a new method for the qualitative and quantitative detection of hydrophobing injection media used as a subsequent masonry-seal against rising damp. Within the scope of this detection method, condensation processes are carried out on the sampling material in the environmental scanning electron microscope with determination of the hydrophobic properties. With this new method statements can be made about the actual sealing quality in the injection level compared to untreated masonry areas. The method can be applied to all capillary masonry treated with a subsequent hydrophobic injection

Optimal execution and speculation with trade signals

We propose a price impact model where changes in prices are purely driven by the order flow in the market. The stochastic price impact of market orders and the arrival rates of limit and market orders are functions of the market liquidity process which reflects the balance of the demand and supply of liquidity. Limit and market orders mutually excite each other so that liquidity is mean reverting. We use the theory of Meyer-$\sigma$-fields to introduce a short-term signal process from which a trader learns about imminent changes in order flow. In this setting, we examine an optimal execution problem and derive the Hamilton--Jacobi--Bellman (HJB) equation for the value function. The HJB equation is solved numerically and we illustrate how the trader uses the signal to enhance the performance of execution problems and to execute speculative strategies

Investigation on Building Materials with the SEM in the ESEM mode to Demonstrate Their Capillarity Using the Contact Angle Method

The chapter describes the use of the Scanning Electron Microscope (SEM) in the Environmental Scanning Electron Microscope (ESEM) mode on building materials, whose capillarity is to be examined. The abbreviation SEM means Scanning Electron Microscope. The abbreviation ESEM means Environmental Scanning Electron Microscope. On the basis of condensation in the ESEM, the hydrophobicity of capillary building materials is demonstrated with the help of the contact angle method. In the chapter, the investigation in the ESEM is shown using capillary building materials that have been given subsequent injections. Due to the problem of rising masonry moisture on capillary masonry in the absence of a cross-section sealing, injection agents, which have a hydrophobic and pore-filling effect, subsequently are used in the borehole method. Such a subsequent masonry sealing must be checked for effectiveness. In addition to already existing macroscopic methods, a new microscopic detection method is presented. This detection method uses ESEM technology in the SEM to generate and detect in situ dew processes at samples taken from the injection level of the examined masonry. The output of the results is done by image or film. By means of the condensation with the medium of water, the contact angle measurement method on the dew drops can be used to make accurate statements about the water-repellent capabilities of the examined sample and thus about the sealing success. There are detectable correlations to the macroscopic detection methods. The contact angles measured in the ESEM during condensation are connected to the conventional macroscopic measurement methods. The method presented in this chapter offers the advantage to have very small samples and to be investigated in a short time with very precise results. The new detection method is suitable for practical use

Fabrication of High‐Quality Thin Single‐Crystal Diamond Membranes with Low Surface Roughness

Certain aspects before and during the fabrication of single-crystal diamond (SCD) membranes are highlighted, which are decisive to obtain high-quality membranes with low surface roughness values around 0.2 nm on a small area scale. In addition to the requirements for the starting material, including a high planarity and a moderate surface roughness, the importance of cleaning processes to minimize particles and impurities before and during the structuring is emphasized. With the help of a planarization procedure, consisting of a combination of different Ar/Cl$_2$ recipes with low etch rates, surface defects like grooves due to polishing are minimized and smooth surfaces are acquired. Severe micromasking can be prevented by the application of a cyclic Ar/Cl$_2$ + O$_2$ recipe, allowing finally the fabrication of defect-minimized and planarized SCD membranes in the thickness range between few microns and a few hundred nanometers. The high quality of the structured SCD membranes is evidenced with a morphological as well as an optical characterization via fiber-based microcavity measurements

Können wir unseren Fachbüchern vertrauen? - Leitlinienkonformität deutscher Lehrbücher bei der präklinischen Behandlung des Schlaganfalls

HINTERGRUND: Bei der Therapie des Schlaganfalls spielt die präklinische Versorgung eine wichtige Rolle. Ziel unseres Projekts war es, die Vollständigkeit und Zuverlässigkeit von medizinischen Lehrbüchern mit Therapieanleitungen zur präklinischen Schlaganfallversorgung zu untersuchen. Lehrbücher sind für Ärzte wie Studenten nach wie vor, trotz der aufkommenden Alternativen in Form digitaler Medien, sehr wichtige Informationsquellen für Examina und medizinische Entscheidungen. METHODEN: Wir führten eine systematische Lehrbuch-Literatursuche gemäß den PRISMA-Kriterien durch. Die Inhalte zur präklinischen Therapie des Schlaganfalls wurden durch zwei unabhängige Untersucher evaluiert. Qualitätsstandard der Evaluation waren die aktuellen Schlaganfall-Leitlinien. Die endgültige Bewertung erfolgte in einem Konsensus Prozess. ERGEBNISSE: Von 68 Lehrbüchern zur Notfallmedizin zwischen 2011 und 2014 konnten 16 mit Inhalten zur präklinischen Therapie des Schlaganfalls bewertet werden. Die meisten untersuchten Lehrbücher zeigten gravierende Auslassungen und Abweichungen im Vergleich zu den Handlungsempfehlungen anerkannter aktueller Leitlinien. In fast allen Büchern fehlten die Quellennachweise. ZUSAMMENFASSUNG: Die meisten Notfallmedizinlehrbücher zur präklinischen Therapie des Schlaganfalls vermitteln momentan nicht die notwendigen Inhalte für eine erfolgreiche Therapie. Wegen fehlender Quellenangaben fehlt den Lesern auch die Möglichkeit Wissensinhalte nachzuvollziehen und zu vertiefen. Es ist dringend notwendig Lehrbuchinhalte auf einen Qualitätsstandard zu bringen, wie er von der evidenz-basierten Medizin gefordert wird

Fabrication and Characterization of Single-Crystal Diamond Membranes for Quantum Photonics with Tunable Microcavities

The development of quantum technologies is one of the big challenges in modern research. Acrucial component for many applications is an efficient, coherent spin–photon interface, and coupling single-color centers in thin diamond membranes to a microcavity is a promising approach. To structure such micrometer thin single-crystal diamond (SCD) membranes with a good quality, it is important to minimize defects originating from polishing or etching procedures. Here, we report on the fabrication of SCD membranes, with various diameters, exhibiting a low surface roughness down to 0.4 nm on a small area scale, by etching through a diamond bulk mask with angled holes. A significant reduction in pits induced by micromasking and polishing damages was accomplished by the application of alternating Ar/Cl2 + O2 dry etching steps. By a variation of etching parameters regarding the Ar/Cl2 step, an enhanced planarization of the surface was obtained, in particular, for surfaces with a higher initial surface roughness of several nanometers. Furthermore, we present the successful bonding of an SCD membrane via van der Waals forces on a cavity mirror and perform finesse measurements which yielded values between 500 and 5000, depending on the position and hence on the membranethickness. Our results are promising for, e.g., an efficient spin–photon interface

Three-dimensional quantification of tree architecture from mobile laser scanning and geometry analysis

The structure and dynamics of a forest are defined by the architecture and growth patterns of its individual trees. In turn, tree architecture and growth result from the interplay between the genetic building plans and environmental factors. We set out to investigate whether (1) latitudinal adaptations of the crown shape occur due to characteristic solar elevation angles at a species’ origin, (2) architectural differences in trees are related to seed dispersal strategies, and (3) tree architecture relates to tree growth performance. We used mobile laser scanning (MLS) to scan 473 trees and generated three-dimensional data of each tree. Tree architectural complexity was then characterized by fractal analysis using the box-dimension approach along with a topological measure of the top heaviness of a tree. The tree species studied originated from various latitudinal ranges, but were grown in the same environmental settings in the arboretum. We found that trees originating from higher latitudes had significantly less top-heavy geometries than those from lower latitudes. Therefore, to a certain degree, the crown shape of tree species seems to be determined by their original habitat. We also found that tree species with wind-dispersed seeds had a higher structural complexity than those with animal-dispersed seeds (p < 0.001). Furthermore, tree architectural complexity was positively related to the growth performance of the trees (p < 0.001). We conclude that the use of 3D data from MLS in combination with geometrical analysis, including fractal analysis, is a promising tool to investigate tree architecture

Evaluating the Performance of Ultra-Low-Field MRI for In-vivo 3D Current Density Imaging of the Human Head

Magnetic fields associated with currents flowing in tissue can be measured non-invasively by means of zero-field-encoded ultra-low-field magnetic resonance imaging (ULF MRI) enabling current density imaging (CDI) and possibly conductivity mapping of human head tissues. Since currents applied to a human are limited by safety regulations and only a small fraction of the current passes through the relatively high-resistive skull, a sufficient signal-to-noise ratio (SNR) may be difficult to obtain when using this method. In this work, we study the relationship between the image SNR and the SNR of the field reconstructions from zero-field-encoded data. We evaluate these results for two existing ULF MRI scanners, one ultra-sensitive single-channel system and one whole-head multi-channel system, by simulating sequences necessary for current-density reconstruction. We also derive realistic current-density and magnetic-field estimates from finite-element-method simulations based on a three-compartment head model. We found that existing ULF-MRI systems reach sufficient SNR to detect intra-cranial current distributions with statistical uncertainty below 10%. However, they also reveal that image artifacts influence the reconstruction quality. Further, our simulations indicate that current-density reconstruction in the scalp requires a resolution less than 5 mm and demonstrate that the necessary sensitivity coverage can be accomplished by multi-channel devices.Comment: 18 pages, 8 figures. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 68686

Transplantation of Chemically Processed Decellularized Meniscal Allografts: A Pilot Sheep Study

Objective The aim of this study was to evaluate the chondroprotective effect of chemically decellularized meniscal allografts transplanted into the knee joints of adult merino sheep. Methods Lateral sheep meniscal allografts were chemically processed by a multistep method to yield acellular, sterile grafts. The grafts were transplanted into the knee joints of sheep that were treated by lateral meniscectomy. Joints treated by meniscectomy only and untreated joints served as controls. The joints were analyzed morphologically 6 and 26 weeks after surgery by the macroscopical and histological OARSI (Osteoarthritis Research Society International) score. Additionally, the meniscal grafts were biomechanically tested by cyclic indentation. Results Lateral meniscectomy was associated with significant degenerative changes of the articular cartilage of the lateral joint compartment. Transplanted lateral meniscal allografts retained their integrity during the observation period without inducing significant synovitis or foreign body reactions. Cellular repopulation of the grafts was only present on the surface and the periphery of the lateral meniscus, but was still completely lacking in the center of the grafts at week 26. Transplantation of processed meniscal allografts could not prevent degenerative changes of the articular cartilage in the lateral joint compartment. Compared with healthy menisci, the processed grafts were characterized by a significantly reduced dynamic modulus, which did not improve during the observation period of 26 weeks in vivo. Conclusion Chemically decellularized meniscal allografts proved their biocompatibility and durability without inducing immunogenic reactions. However, insufficient recellularization and inferior stiffness of the grafts hampered chondroprotective effects on the articular cartilage