Toxicity of perfluorinated carboxylic acids for aquatic organisms

Toxicity of perfluorinated carboxylic acids with carbon chain C8 to C12 were tested with oligochaeta Tubifex tubifex. Toxicity was evaluated as the exposure time ET50 from onset of damage of the oligochaeta in saturated aqueous solutions. The ET50 fluctuated between 25 and 257 minutes. No statistically significant difference was found among the C8, C9 and C12 acids (ET50 between 143 and 257 minutes with large standard deviation). The acids with carbon chain C10 and C11 induced the effect significantly quicker (25 to 47 minutes). No acute toxicity measured in the three-minute test was observed in any case

Mismatch repair deficiency predicts response of solid tumors to PD-1 blockade.

The genomes of cancers deficient in mismatch repair contain exceptionally high numbers of somatic mutations. In a proof-of-concept study, we previously showed that colorectal cancers with mismatch repair deficiency were sensitive to immune checkpoint blockade with antibodies to programmed death receptor-1 (PD-1). We have now expanded this study to evaluate the efficacy of PD-1 blockade in patients with advanced mismatch repair-deficient cancers across 12 different tumor types. Objective radiographic responses were observed in 53% of patients, and complete responses were achieved in 21% of patients. Responses were durable, with median progression-free survival and overall survival still not reached. Functional analysis in a responding patient demonstrated rapid in vivo expansion of neoantigen-specific T cell clones that were reactive to mutant neopeptides found in the tumor. These data support the hypothesis that the large proportion of mutant neoantigens in mismatch repair-deficient cancers make them sensitive to immune checkpoint blockade, regardless of the cancers\u27 tissue of origin

Comparison of the Models of the Air Gauge Static Characteristics

In the article, the authors analyze and discuss several models used to the calculation of air gauge characteristics. The model based on the actual mass flow (which is smaller than the theoretical one) was proposed, too. Calculations have been performed with a dedicated software with the second critical parameters included. The air gauge static characteristics calculated with 6 different models were compared with the experimental data. It appeared that the second critical parameters model (SCP) provided the characteristics close to the experimental ones, with an error of ca. 3% within the air gauge measuring range

Mathematical Model of Dynamic Work Conditions in the Measuring Chamber of an Air Gauge

The goal of the proposed computational model was to evaluate the dynamical properties of air gauges in order to exploit them in such industrial applications as in-process control, form deviation measurement, dynamical measurement. The model is based on Reynolds equations complemented by the k-ε turbulence model. The boundary conditions were set in different areas (axis of the chamber, side surfaces, inlet pipeline and outlet cross-section) as Dirichlet's and Neumann's ones. The TDMA method was applied and the efficiency of the calculations was increased due to the "line-by-line" procedure. The proposed model proved to be accurate and useful for non-stationary two-dimensional flow through the air gauge measuring chamber

Structure, Mechanical Properties, and High-Temperature Stability of ZrB2- and HfB2-Based Materials

The structure, mechanical characteristics, and high-temperature stability in vacuum and air of ZrB2 and HfB2-based materials sintered at a high quasi-hydrostatic pressure (4.1 GPa) under hot pressing (at a pressure of 30 MPa) with and without SiC and Si3N4 additives have been studied. It has been shown that short-term sintering (4 min) under high pressure conditions and at a comparatively low temperature (1800°C) essentially improves the mechanical properties of these materials as compared to the similar materials synthesized by the other method (hot pressing and spark-plasma sintering). In the case of sintering at a high pressure (4.1 GPa), the addition of 20 wt % SiC to ZrB2 and 30 wt % SiC to HfB2 leads to a decrease in the specific gravity of ZrB2 and HfB2 and increases their hardness by 17 and 46% and fracture toughness by 40 and 21%, respectively. When SiC is added, there occurs the formation of solid solutions through the mutual diffusion of C and Si into the ZrB2 or HfB2 matrix phases and the slight diffusion of Zr and Hf into SiC-enriched areas. The improvement of the mechanical properties of ZrB2 and HfB2 sintered at a high pressure without additives is explained by the formation of stronger bonds between the sintered material grains. The addition of SiC to ZrB2 slightly decreases the Young modulus, but increases the damping ability of the synthesized materials. The simultaneous addition of SiC and Si3N4 to ZrB2 leads to an increase in the hardness to a smaller extent, but results in a further increase in fracture toughness. The melting temperature in vacuum of sintered ZrB2 and HfB2 has proven to be much higher as compared to the materials with SiC additives. The composite material synthesized from a HfB2–30 wt % SiC mixture has a density ρ = 6.21 g/cm3 , a microhardness HV(9.8 N) = 38.1 ± 1.4 GPa, HV(49 N) = 27.7 ± 0.24 GPa, HV(98 N) = 26.3 ± 2.03 GPa, and a fracture toughness KІс(9.8 N) = 8.2 ± 0.2 MPa m0.5, KІс(49 N) = 6.8 ± 0.6 MPa m0.5, KІс(98 N) = 6.4 ± 0.11 MPa m0.5, which are much higher than the similar characteristics of HfB2 sintered under the same conditions, but without the additives