Noxic effects of polystyrene microparticles on murine macrophages and epithelial cells

Abstract Microplastic (MP) contamination has been identified as an ecological problem with an increasing impact on everyday life. Yet, possible effects of MP at the cellular level are still poorly understood. Here, the interaction of murine macrophages (J774A.1, ImKC) and epithelial cells (STC-1, BNL CL.2) with well-characterized poly(styrene) MP particles (MPP) of varying sizes (0.2–6.0 µm) was studied. Macrophages are expected to actively engulf particles which could be confirmed in this study, while epithelial cells are found in tissues with direct contact with ingested or inhaled MPP. Here, the epithelial cells from both investigated cell lines did not ingest MPP in significant numbers. Concomitantly, no cytotoxic effects nor any influence on cellular proliferation were observed. Cells from the two macrophage cell lines showed high ingestion of MPP of all sizes, but cytotoxic effects were observed only for one of them (ImKC) and only at MPP concentrations above 250 µg/mL. Indications of cellular stress as well as effects on cell proliferation were observed for cell populations with high particle cell interactions

Will Your Household Adopt Your New Robot?

Domestic robots have slowly found their way into some of our homes and onto the shelves of major stores selling technical appliances. Who hasn’t already seen or heard of robots that vacuum or mow the lawn? As researchers in robotics, we feel this growing commercial success is a great opportunity to learn about robot adoption processes. Leaving the marketing buzz and usual fantasies about robot invasions aside, we are curious to find out how robots are perceived by users. Are robots revolutionizing people’s practices at home? Understanding the adoption of such robots is also central, as it helps to pinpoint crucial factors to be taken into account while designing new robots. Other questions we wish to consider include: What convinces people to adopt them? What stops people from adopting them? What features or concepts should be transferred to future robot generations? To answer these questions, we conducted an ethnographic study that analyzed how people adopted or rejected a vacuum-cleaning robot in their homes [1]. We gave a popular commercially available robot (iRobot’s Roomba) to nine households and observed them over a period of six months [2]. We recruited households with and without children, pets, and gardens. We analyzed cleaning habits before Roomba. We then observed how they evolved from the moment we brought them the robot: at installa- tion, after two weeks, and then two and four months after installation

Push-Out Bond Strength Assessment of Different Post Systems at Different Radicular Levels of Endodontically Treated Teeth.

This study assessed the bond strength of prefabricated post systems at different root levels of endodontically treated teeth. One-rooted human premolars (N = 70; n = 10) were cut to 2 mm above the cement-enamel junction. Root canals were treated and randomly assigned to one of the seven post systems: T: Titanium (Mooser), ZrO: Zirconia (Cosmopost), G: Fiber (FRC Postec Plus), E1: Fiber (Direct) (Everstick post), E2: Fiber (Indirect) (Everstick post), PP: Fiber (PinPost), and LP: Injectable Resin/Fiber composite (EverX Posterior). All posts were luted using a resin cement (Variolink II), and the roots were sectioned at the coronal, middle, and apical root levels. Push-out tests were performed in the Universal Testing Machine (0.5 mm/min). Data (MPa) were analyzed using two-way ANOVA and Tukey's tests (α = 0.05). The results showed that the bond strength (mean ± SD) of E2 posts were highest (5.3 ± 2.7) followed by PP (4.1 ± 2.0); G (4.0 ± 1.6); LP (2.6 ± 1.9): T (2.2 ± 1.5) and ZrO (1.9 ± 1.0) posts systems. No significant differences were found in bond strength of all post systems. The bond strength in the coronal root level was the highest with 3.6 ± 2.2 MPa. The bond strength of FRC post systems was significantly higher than those of rigid posts of titanium or ZrO2. Bond strength results were the highest in the coronal root level for all tested post systems but did not differ significantly from the other two root levels

(Co)constructing critical pedagogies: Expanding on our department’s approach to language teaching

In this report, we—the members of a curriculum working group (CWG) in Penn State’s German department—describe our efforts to decenter our German language sequence by integrating critical pedagogies into our department’s existing communicative language teaching (CLT) approach. We trace our process towards this goal, beginning with an exploration into and analysis of two critical pedagogies, namely Antiracist Pedagogy (ARP) and Social Justice Pedagogy (SJP). We ultimately adopt SJP because we find it to be a better fit for our purposes in German language instruction. We offer a framework to evaluate and didacticize existing as well as newly created course materials, guided by social justice (SJ) learning objectives. To illustrate our work, we describe the creation and implementation of an instructional unit in an intermediate German language course. Reflections from this course’s instructor and student reactions concerning this unit’s instruction—as well as SJP in the language classroom in general—make evident the importance of critical perspectives regarding curricular development in fostering equitable classrooms

CD4+ T Cell Polarization in Mice Is Modulated by Strain-specific Major Histocompatibility Complex–independent Differences within Dendritic Cells

Resistance and susceptibility to Leishmania major in mice are determined by multiple genes and correlate with the preferential development of Th1 and Th2 responses, respectively. Here, we found that CD11b+ dendritic cells (DCs) prime parasite-specific CD4+ T cells in both susceptible BALB/c (H2-d) and resistant B10.D2 (H2-d) mice. However, BALB/c and B10.D2 DCs from L. major–infected mice differ in their ability to polarize naive T cells into Th1 or Th2 effector cells. This difference is cell-intrinsic, is not restricted to H2-d mice, and is observed with both parasite-specific and allospecific CD4+ T cells. Thus, strain-specific differences within CD11b+ DCs influence the ability of inbred mice to mount polarized CD4+ T cell responses

In vitro cultivation of primary intestinal cells from Eisenia fetida as basis for ecotoxicological studies

The earthworm Eisenia fetida is a commonly used model organism for unspecific soil feeders in ecotoxicological studies. Its intestinal cells are the first to encounter possible pollutants co-ingested by the earthworm, which makes them prime candidates for studies of toxic effects of environmental pollutants on the cellular as compared to the organismic level. In this context, the aim of this study was to demonstrate the suitability of preparations of primary intestinal E. fetida cells for in vitro ecotoxicological studies. For this purpose, a suitable isolation and cultivation protocol was established. Cells were isolated directly from the intestine, maintaining >85% viability during subsequent cultivations (up to 144 h). Exposure to established pollutants and soil elutriates comprising silver nanoparticles and metal ions (Cu(2+), Cd(2+)) induced a significant decrease in the metabolic activity of the cells. In case of microplastic particles (MP particles), namely 0.2, 0.5, 2.0, and 3.0 µm diameter polystyrene (PS) beads as well as 0.5 and 2.0 µm diameter polylactic acid (PLA) beads, no active uptake was observed. Slight positive as well as negative dose and size dependent effects on the metabolism were seen, which to some extent might correlate with effects on the organismic level

The Reservoir Age Effect Varies With the Mobilization of Pre-Aged Organic Carbon in a High-Altitude Central Asian Catchment

Lake sediments provide excellent archives to study past environmental and hydrological changes at high temporal resolution. However, their utility is often restricted by chronological uncertainties due to the “ reservoir age effect ” (RAE), a phenomenon that results in anomalously old radiocarbon ages of total organic carbon (TOC) samples that is mainly attributed to the contribution of pre-aged carbon from aquatic organisms. Although the RAE is a well-known problem especially in high altitude lakes, detailed studies analyzing the temporal variations in the contribution of terrestrial and aquatic organic carbon (OC) on the RAE are scarce. This is partially due to the complexity of isolating individual compounds for subsequent compound-speci fi c radiocarbon analysis (CSRA). We developed a rapid method for isolating individual short-chain (C 16 and C 18 ) and long-chain ( > C 24 ) saturated fatty acid methyl esters (FAMEs) by using high-pressure liquid chromatography (HPLC). Our method introduces only minor contaminations (0.50 ± 0.22 µg dead carbon on average) and requires only few injections ( ≤ 10), therefore offering clear advantages over traditional preparative gas chromatography (prep-GC). Here we show that radiocarbon values ( Δ 14C) of long-chain FAs, which originate from terrestrial higher plant waxes, re fl ect carbon from a substantially pre-aged OC reservoir, whereas the Δ 14C of short-chain FAs that originate from aquatic sources were generally less pre-aged. 14 C ages obtained from the long-chain FAs are in closer agreement with 14 C ages of the corresponding bulk TOC fraction, indicating a high control of pre-aged terrestrial OC input from the catchment on TOC-derived 14 C ages. Variations in the age offset between terrestrial and aquatic biomarkers are related to changes in bulk sediment log(Ti/K) that re fl ect variations in detrital input from the catchment. Our results indicate that the chronological offset between terrestrial and aquatic OC in this high-altitude catchment is mainly driven by temporal variations in the mobilization of pre-aged OC from the catchment. In conclusion, to obtain accurate and process-speci fi c lake sediment chronologies, attention must be given to the temporal dynamics of the RAE. Variations in the apparent ages of aquatic and terrestrial contributions to the sediment and their mass balance can substantially alter the reservoir age effect