Statistical hierarchical clustering algorithm for outlier detection in evolving data streams

Machine Learning - Anomaly detection is a hard data analysis process that requires constant creation and improvement of data analysis algorithms. Using traditional clustering algorithms to analyse...     

Microstructure and mechanical properties of Mg-5Li-1Al sheets prepared by accumulative roll bonding

Ultrafine-grain and high-strength Mg-5Li-1Al sheets were prepared by accumulative roll bonding (ARB) process. Evolution of microstructure and mechanical properties of ARB-processed Mg-5Li-1Al sheets was investigated.Results show that, during ARB process, the evolution of deformation mechanism of t Mg-5Li-1Al alloy is as follows: twinning deformation, shear deformation, forming macro shear zone, and finally dynamic recrystallization (DRX). The grain refining mechanism changes from twin DRX to rotation DRX. With the increase in ARB cycles, strength of the Mg-5Li-1Al sheets is enhanced, whilst elongation varies slightly. With the increase in rolling cycles, anisotropy of mechanical properties decreases. It is conclusive that strain hardening and grain refinement dominate the strengthening mechanism of Mg-5Li-1Al alloy.     

Digital PCR Panel for Sensitive Hematopoietic Chimerism Quantification after Allogeneic Stem Cell Transplantation

Accurate and sensitive determination of hematopoietic chimerism is a crucial diagnostic measure after allogeneic stem cell transplantation to monitor engraftment and potentially residual disease. Short tandem repeat (STR) amplification, the current “gold standard” for chimerism assessment facilitates reliable accuracy, but is hampered by its limited sensitivity (≥1%). Digital PCR (dPCR) has been shown to combine exact quantification and high reproducibility over a very wide measurement range with excellent sensitivity (routinely ≤0.1%) and thus represents a promising alternative to STR analysis. We here aimed at developing a whole panel of digital-PCR based assays for routine diagnostic. To this end, we tested suitability of 52 deletion/insertion polymorphisms (DIPs) for duplex analysis in combination with either a reference gene or a Y-chromosome specific PCR. Twenty-nine DIPs with high power of discrimination and good performance were identified, optimized and technically validated. We tested the newly established assays on retrospective patient samples that were in parallel also measured by STR amplification and found excellent correlation. Finally, a screening plate for initial genotyping with DIP-specific duplex dPCR assays was designed for convenient assay selection. In conclusion, we have established a comprehensive dPCR system for precise and high-sensitivity measurement of hematopoietic chimerism, which should be highly useful for clinical routine diagnostics.     

Hot-pressed ceramic SiC–YAG materials

Dense SiC-based ceramic materials containing yttrium aluminum garnet (YAG) as an oxide sintering aid have been prepared by hot pressing in the temperature range 1750–1850°C. As a result of melting, the oxides fill spaces between the SiC particles, contributing to the densification of the material and mass transport during the hot pressing process. The present results demonstrate that relatively small amounts of the oxides (≤5 wt %) are needed to ensure a high degree of densification of the SiC–YAG materials. The best physicomechanical properties are offered by the SiC + 3 wt % YAG material sintered at a temperature of 1850°C: ρ = 3.24 ± 0.01 g/cm³, П = 1.1 ± 0.1%, σ_b = 640 ± 10 MPa; K_Ic = 6.4 ± 0.2 MPa m^1/2, Еel = 410 ± 20 GPa, and HV = 26.0 ± 0.2 GPa. This material experiences predominantly intercrystalline fracture.     

Temperature-induced impacts on groundwater quality and arsenic mobility in anoxic aquifer sediments used for both drinking water and shallow geothermal energy production

Aquifers used for the production of drinking water are increasingly being used for the generation of shallow geothermal energy. This causes temperature perturbations far beyond the natural variations in aquifers and the effects of these temperature variations on groundwater quality, in particular trace elements, have not been investigated. Here, we report the results of column experiments to assess the impacts of temperature variations (5°C, 11°C, 25°C and 60°C) on groundwater quality in anoxic reactive unconsolidated sandy sediments derived from an aquifer system widely used for drinking water production in the Netherlands. Our results showed that at 5 °C no effects on water quality were observed compared to the reference of 11°C (in situ temperature). At 25°C, As concentrations were significantly increased and at 60 °C, significant increases were observed pH and DOC, P, K, Si, As, Mo, V, B, and F concentrations. These elements should therefore be considered for water quality monitoring programs of shallow geothermal energy projects. No consistent temperature effects were observed on Na, Ca, Mg, Sr, Fe, Mn, Al, Ba, Co, Cu, Ni, Pb, Zn, Eu, Ho, Sb, Sc, Yb, Ga, La, and Th concentrations, all of which were present in the sediment. The temperature-induced chemical effects were probably caused by (incongruent) dissolution of silicate minerals (K and Si), desorption from, and potentially reductive dissolution of, iron oxides (As, B, Mo, V, and possibly P and DOC), and mineralisation of sedimentary organic matter (DOC and P).