318 research outputs found
CANE: A Controlled Application Environment for privacy protection in ITS
Many of the applications proposed for intelligent transportation systems (ITS) need to process and communicate detailed personal identifiable information. Examples are detailed location traces or unique identifiers for authentication towards paid services. Existing applications often run as monolithic black boxes inside users’ cars. Hence, users cannot verify that applications behave as expected. We propose CANE, an application sandboxing approach that enhances user control over privacy properties while, at the same time, supporting common application requirements. CANE makes privacy-relevant application properties explicit and allows their analysis and enforcement during application runtime. We evaluate CANE using a common ITS use case and demonstrate feasibility with a proof-of-concept implementation
High-aluminum-affinity silica is a nanoparticle that seeds secondary aluminosilicate formation.
Despite the importance and abundance of aluminosilicates throughout our natural surroundings, their formation at neutral pH is, surprisingly, a matter of considerable debate. From our experiments in dilute aluminum and silica containing solutions (pH ~ 7) we previously identified a silica polymer with an extraordinarily high affinity for aluminium ions (high-aluminum-affinity silica polymer, HSP). Here, further characterization shows that HSP is a colloid of approximately 2.4 nm in diameter with a mean specific surface area of about 1,000 m(2) g(-1) and it competes effectively with transferrin for Al(III) binding. Aluminum binding to HSP strongly inhibited its decomposition whilst the reaction rate constant for the formation of the β-silicomolybdic acid complex indicated a diameter between 3.6 and 4.1 nm for these aluminum-containing nanoparticles. Similarly, high resolution microscopic analysis of the air dried aluminum-containing silica colloid solution revealed 3.9 ± 1.3 nm sized crystalline Al-rich silica nanoparticles (ASP) with an estimated Al:Si ratio of between 2 and 3 which is close to the range of secondary aluminosilicates such as imogolite. Thus the high-aluminum-affinity silica polymer is a nanoparticle that seeds early aluminosilicate formation through highly competitive binding of Al(III) ions. In niche environments, especially in vivo, this may serve as an alternative mechanism to polyhydroxy Al(III) species binding monomeric silica to form early phase, non-toxic aluminosilicates
Si isotope fractionation during precipitation of silica by cyclic freezing and adsorption of monosilicic acid on gibbsite [Abstract]
Oxygen and clumped isotope fractionation during the formation of Mg calcite via an amorphous precursor
The oxygen and clumped isotope signatures of Mg calcites are routinely used as environmental proxies in a broad range of surroundings, where Mg calcite forms either by classical nucleation or via an amorphous calcium magnesium carbonate (ACMC) precursor. Although the (trans)formation of ACMC to Mg calcite has been identified for an increasing number of settings, the behavior of both isotope proxies throughout this stage is still unexplored. In the present study ACMC (trans)formation experiments were carried out at constant pH (8.30 ± 0.03) and temperature (25.00 ± 0.03 °C) to yield high Mg calcite (up to 20 mol% Mg). The experimental data indicate that the oxygen isotope values of the amorphous and/or crystalline precipitate (δO, analyzed as Mg calcite) are affected by the (trans)formation pathway, whereas clumped isotopes (Δ = Δ) are not. The oxygen isotope evolution of the solid phase can be explained by the instantaneous trapping of the isotopic composition of the aqueous (bi)carbonate complexes. This entrapment results in remarkably high 10ln(α) values of ∼33‰ at the initial ACMC formation stage. During the ACMC transformation process the oxygen isotope equilibrium is approached rapidly between Mg calcite and water (ΔO = 30.3 ± 0.4‰) and no isotopic memory of the initial to the final Mg calcite at the end of the experiment occurs. The implications for oxygen and clumped isotope signatures of Mg calcite formed via ACMC are discussed in the aspects of various scenarios of (trans)formation conditions and their use as environmental proxies
Two-Photon Microscopy Allows Imaging and Characterization of Cochlear Microvasculature In Vivo
Impairment of cochlear blood flow has been discussed as factor in the pathophysiology of various inner ear disorders. However, the microscopic study of cochlear microcirculation is limited due to small scale and anatomical constraints. Here, two-photon fluorescence microscopy is applied to visualize cochlear microvessels. Guinea pigs were injected with Fluorescein isothiocyanateor Texas red-dextrane as plasma marker. Intravital microscopy was performed in four animals and explanted cochleae from four animals were studied. The vascular architecture of the cochlea was visualized up to a depth of 90.0 +/- 22.7 mu m. Imaging yielded a mean contrast-to-noise ratio (CNR) of 3.3 +/- 1.7. Mean diameter in vivo was 16.5 +/- 6.0 mu m for arterioles and 8.0 +/- 2.4 mu m for capillaries. In explanted cochleae, the diameter of radiating arterioles and capillaries was measured with 12.2 +/- 1.6 mu m and 6.6 +/- 1.0 mu m, respectively. The difference between capillaries and arterioles was statistically significant in both experimental setups (P < 0.001 and P = 0.022, two-way ANOVA). Measured vessel diameters in vivo and ex vivo were in agreement with published data. We conclude that two-photon fluorescence microscopy allows the investigation of cochlear microvessels and is potentially a valuable tool for inner ear research
Morphology control in modulated synthesis of metal-organic framework CPO-27
Under embargo until: 2020-08-27The CPO-27/MOF-74 series is among the most investigated metal-organic frameworks because of their usefulness in a diverse range of applications. For specific applications, it will be important to control the shape and size of the particles or crystallites of the material. The modulation approach has been successfully used to direct these parameters in the synthesis of MOFs. Here, we report the synthesis of CPO-27-Ni in the presence of different ratios of benzoic acid and acetic acid as modulators. Yields, powder X-ray diffraction data, scanning electron microscopy results, and elemental, thermogravimetric, and gas sorption analyses are compared to study the influence of the modulator on the product. The results show that we have successfully synthesized pure CPO-27-Ni independent of the amount of modulator. The modulator affects the resulting morphology of the crystalline product with a defined variation of particle sizes and shapes. In addition, ESI-MS has been employed in probing the reaction solutions. It shows the preferred formation of complexes between the metal cation and the modulator, thus indicating that the ligand substitution plays a major role in the crystal growth.acceptedVersio
Sulfate attack - Reaction mechanisms revealed by a multi proxy approach
The destructive effects of sulfate attack on concrete structures are well known, but the reaction paths and mechanisms that cause the deterioration are still under debate. The aim of this study is to contribute to a deeper understanding on investigating concrete damage by introducing a novel and promising multi proxy approach method. The methodology comprises advanced mineralogical and hydro-geochemical methods as well as stable isotope signals. Investigations were performed on various field case studies in Austria, where the locally occurring ground water was classified as slightly aggressive to concrete, in accordance to DIN EN 206-1. Nevertheless intense concrete damage related to sulfate attack was found. Severely damaged mushy concrete consisted mainly of thaumasite, secondary calcite, gypsum and relicts of aggregate. The expressed interstitial solutions from such material were extremely enriched in SO4 (up to >30000 mg L-1). Stable hydrogen and oxygen isotope were applied successfully and demonstrated that the degree of evaporation provoked enrichments in SO4 and other dissolved, potentially harmful ions such as Cl. Furthermore, the enormous accumulation of incompatible trace elements (e.g. Rb and Li) clearly indicated that numerous wetting and drying cycles had occurred. Such a highly dynamic system is known to induce severe destructive effects on concrete. In this study we demonstrate that the application of a multi proxy approach can provide a better understanding of the complexity of reaction mechanisms involving sulfate attack on concrete structures. More detailed knowledge on the individual reactions that promote concrete damage in field structures will help to find specific counter measures for already affected buildings and to develop tailored concrete recipes, applications and constructive measures for future projects
Groundwater flow dynamics in the complex aquifer system of Gidabo River Basin (Ethiopian Rift): a multi-proxy approach
- …