Why do people use portable air purifiers? Evidence from occupant surveys and air quality monitoring in homes in three European cities

One of the most widely available technologies to clean the air in homes of particulate matter of less than 2.5 µm in diameter (PM2.5), known to have negative health impacts, are portable home air purifiers (HAPs). This paper presents research which (1) explored the effectiveness of HAPs in real-world conditions in 57 homes in three European cities; (2) examined if HAPs affect users’ perceptions of the indoor air quality (IAQ) at home; and (3) considered the motivations for occupants’ operation of HAPs. Results from this study found that PM2.5 concentrations in bedrooms were reduced by 45% to 69%; perceptions of IAQ were not correlated with measured high PM2.5 levels; occupants reported the HAPs to have a ‘cooling’ effect, which may explain why the predominant driver of HAP use was thermal comfort, rather than IAQ, in all three cities. The latter finding was supported by a statistically significant increase in the probability of HAP use with increasing indoor temperatures. If the operation of HAPs can be managed, or fully automated, to reflect indoor air pollution levels rather than thermal conditions, better pollutant reduction would be feasible and their use to reduce PM2.5 may help mitigate the negative health effects of exposure whilst at home

Rho GTPase function in flies: insights from a developmental and organismal perspective.

Morphogenesis is a key event in the development of a multicellular organism and is reliant on coordinated transcriptional and signal transduction events. To establish the segmented body plan that underlies much of metazoan development, individual cells and groups of cells must respond to exogenous signals with complex movements and shape changes. One class of proteins that plays a pivotal role in the interpretation of extracellular cues into cellular behavior is the Rho family of small GTPases. These molecular switches are essential components of a growing number of signaling pathways, many of which regulate actin cytoskeletal remodeling. Much of our understanding of Rho biology has come from work done in cell culture. More recently, the fruit fly Drosophila melanogaster has emerged as an excellent genetic system for the study of these proteins in a developmental and organismal context. Studies in flies have greatly enhanced our understanding of pathways involving Rho GTPases and their roles in development

Galectin-1, a gene preferentially expressed at the tumor margin, promotes glioblastoma cell invasion

BACKGROUND: High-grade gliomas, including glioblastomas (GBMs), are recalcitrant to local therapy in part because of their ability to invade the normal brain parenchyma surrounding these tumors. Animal models capable of recapitulating glioblastoma invasion may help identify mediators of this aggressive phenotype. METHODS: Patient-derived glioblastoma lines have been propagated in our laboratories and orthotopically xenografted into the brains of immunocompromized mice. Invasive cells at the tumor periphery were isolated using laser capture microdissection. The mRNA expression profile of these cells was compared to expression at the tumor core, using normal mouse brain to control for host contamination. Galectin-1, a target identified by screening the resulting data, was stably over-expressed in the U87MG cell line. Sub-clones were assayed for attachment, proliferation, migration, invasion, and in vivo tumor phenotype. RESULTS: Expression microarray data identified galectin-1 as the most potent marker (p-value 4.0 x 10(-8)) to identify GBM cells between tumor-brain interface as compared to the tumor core. Over-expression of galectin-1 enhanced migration and invasion in vitro. In vivo, tumors expressing high galectin-1 levels showed enhanced invasion and decreased host survival. CONCLUSIONS: In conclusion, cells at the margin of glioblastoma, in comparison to tumor core cells, have enhanced expression of mediators of invasion. Galectin-1 is likely one such mediator. Previous studies, along with the current one, have proven galectin-1 to be important in the migration and invasion of glioblastoma cells, in GBM neoangiogenesis, and also, potentially, in GBM immune privilege. Targeting this molecule may offer clinical improvement to the current standard of glioblastoma therapy, i.e. radiation, temozolomide, anti-angiogenic therapy, and vaccinotherapy

Validation of the AERIUS air quality model

De luchtkwaliteit in Nederland wordt gemonitord in het Nationaal Samenwerkingsprogramma Luchtkwaliteit (NSL). De luchtkwaliteit wordt berekend met behulp van technische rekenregels die voldoen aan de wettelijk voorgeschreven standaard rekenmethoden voor luchtkwaliteit. Het gaat hierbij specifiek om de rekenmethoden voor de luchtkwaliteit langs wegen in stedelijk gebied en rond snelwegen. Het rekenmodel voor het NSL is nu vervangen door AERIUS lucht en is gevalideerd als rekenmodel luchtkwaliteit. In dit rapport wordt de validatie van AERIUS lucht toegelicht. Een nieuw rekenmodel luchtkwaliteit wordt standaard gevalideerd door het RIVM. Dat gebeurt door de resultaten te vergelijken met die van het rekenmodel van het RIVM (TREDM). Het rekenmodel van het RIVM werkt ook met de wettelijk voorgeschreven standaardrekenmethoden. Om mogelijke discussies over de werkwijze te voorkomen heeft een onafhankelijke organisatie het validatieproces gecontroleerd. Volgens hen is de validatie goed uitgevoerd. Zie rapport: https://vito.be/sites/vito.be/files/rapport_rivm2.pdf De oude NSL-rekenmethode is van 2010 tot en met 2019 gebruikt. Het nieuwe model sluit aan bij de laatste ontwikkelingen in de wetenschap en ict. Het nieuwe model is in opdracht van het ministerie van Infrastructuur en Waterstaat (IenW) gebouwd. Zie ook rapport: Actualisering en addenda SRM-1 en SRM-2 https://www.rivm.nl/bibliotheek/rapporten/2020-0118.pdfThe air quality in the Netherlands is monitored in the National Air Quality Cooperation Program (NAQCP). The air quality is calculated with the help of technical calculation rules that comply with the legally mandated calculation methods for air quality. More specifically, we are talking here about the air quality alongside roads in urban areas and near motorways. The NAQCP calculation model has now been replaced by AERIUS air, which has been validated as an air quality calculation model. This report explains how AERIUS air has been validated. A new calculation model for air quality is, as a rule, validated by RIVM. This is done by comparing the results of the new model with the results of the RIVM calculation model (TREDM). The RIVM calculation model also complies with the legally mandated standard calculation methods. In order to avoid potential discussions about the working procedure, an independent organisation checked the validation process. According to them, the validation process was sound. See report: https://vito.be/sites/vito.be/files/rapport_rivm2.pdf The older NAQCP calculation method was used from 2010 up to and including 2019. The new model is in line with the latest developments in science and ICT. The new model was commissioned by the Ministry of Infrastructure and Water Management. See also report: Updating addenda SRM-1 and SRM-2 https://www.rivm.nl/bibliotheek/rapporten/2020-0118.pdfMinisterie van I&

Probing the Plant Actin Cytoskeleton during Cytokinesis and Interphase by Profilin Microinjection.

We have examined the cytological effects of microinjecting recombinant birch profilin in dividing and interphase stamen hair cells of Tradescantia virginiana. Microinjection of profilin at anaphase and telophase led to a marked effect on cytokinesis; cell plate formation was often delayed, blocked, or completely inhibited. In addition, the initial appearance of the cell plate was wrinkled, thin, and sometimes fragmented. Injection of profilin at interphase caused a thinning or the collapse of cytoplasmic strands and a retardation or inhibition of cytoplasmic streaming in a dose-dependent manner. Confocal laser scanning microscopy of rhodamine-phalloidin staining in vivo revealed that high levels of microinjected profilin induced a degradation of the actin cytoskeleton in the phragmoplast, the perinuclear zone, and the cytoplasmic strands. However, some cortical actin filaments remained intact. The data demonstrate that profilin has the ability to act as a regulator of actin-dependent events and that centrally located actin filaments are more sensitive to microinjected profilin than are cortical actin filaments. These results add new evidence supporting the hypothesis that actin filaments play a crucial role in the formation of the cell plate and provide mechanical support for the cytoplasmic strands in interphase cells

In-vitro method for determining corneal tissue friction and damage due to contact lens sliding

It is postulated that frictional energy due to contact lens rubbing against corneal tissue correlates positively with cell damage; where the damage is due to a fatigue mechanism (repeated stressing). Efforts were made to develop a relatively rapid in-vitro method capable of exploring this postulate. Measurements of the dynamic coefficient of friction (DCoF) between corneal epithelium and contact lenses, associated frictional forces, frictional energy, and corresponding cell damage were made using SkinEthic (Lyon, France) human corneal epithelial (HCE) constructs and commercially available contact lenses. Five silicone hydrogels (SiHs) and two polyhydroxyethlymethacrylate (p-HEMA) lens types were employed. Frictional forces were measured while the lens was rubbed against a construct that was moistened using a tear-like fluid. The exposed constructs were stained, imaged, and processed using a custom Matlab code. The range of DCoF values observed here extended from about 0.04 to 0.07. The frictional energy varied from about 0.03 mJ to 0.08 mJ. The results indicated a moderate correlation (Pearson's R = 0.79, P = 3.4%) between the frictional energy and cell damage. The authors believe that these results support the notion that cell damage can be caused by fatigue. Future efforts should explore how cell damage relates to a potentially more relevant metric, power density