Ultrafine particles: A review about their health effects, presence, generation, and measurement in indoor environments

Human exposure to aerosols has been associated with diseases and death, reducing the population's life expectancy up to a few years. Indoor particulate matter is predominant in determining human exposure to PM because people spend most of their time indoors. Ultrafine particles (UFP) impact the human body differently from PM2.5 or PM10 fractions. Therefore, scientists cannot apply the same approach to assess the effects of UFP and PM on human health. This work summarizes the health effects, generation, and measurement of ultrafine particles in indoor environments through a literature review. When indoor particle generation is low, particle concentration indoors depends strongly on outdoor aerosols, with an indoor-to-outdoor ratio below 1. In buildings with a high indoor particle generation, the average indoor-to-outdoor UFP concentration ratio can reach 14. Combustion, electric heating, and house cleaning are the main generators of UFP indoors. Current standards for UFP assessments do not provide a solid ground for accurate and reliable measurements. Moreover, the lowest detection limit of instruments used to measure UFP concentration can be significantly different while also showing poor repeatability even among instruments with the same manufacturer and model. Consequently, data supplied by studies on UFP health effects are insufficient and inconclusive. Using ultrafine portable monitors would allow determining properly human exposure to PM0.1, but such instruments are expensive for wide use. Since there is a good correlation between UFP and NOX data, low-cost NOX sensors are good candidates to create a dense and accurate monitoring network of UFP, including indoor environments

Two-dimensional numerical simulation of saltating particles using granular kinetic theory

Most granular flows at environmental conditions are unsteady and exhibit a complex physical behavior. Dune formation and migration in the desert are controlled not only by the flow of saltating particles over the sand bed, but also by turbulent atmospheric airflow. In fact, sediments are transported by the atmospheric airflow within a thin layer only a few centimeters above the sandy surface. These jumping particles reach a maximum sediment mass flux level at a certain delay time (known as the “saturation time”) after the initial movement by sliding and rolling begins. Unlike sediment transport in water where the particles are lifted by the turbulent suspension, the saltating particles are kept alive in the layer mainly due to particle-particle and particle-bed collisions. In order to model this Aeolian transport of sand, Jenkins and Pasini [1] proposed a two-fluid model (one-dimensional and steady state) using Granular Kinetic Theory (GKT) to describe the solid-phase stress. The present work extends the original idea of Jenkins and Pasini [1] by using a more robust model of GKT for the kinetic/collisional contributions to the solid-phase stress tensor, together with a friction model activated for sustained contacts between particles. In addition, a standard k-ε turbulence model for the air and a drag model for the interaction between the phases are employed. A rectangular 2D geometry was chosen with a logarithmic profile for the inlet air velocity, along with an initial amount of sand at rest in the lower part of the simulation domain, resembling the particle saltating flow commonly seen in the vertical middle plane within saltation wind tunnels. This model is validated with experimental data from Liu and Dong [2] and the results given by Pasini and Jenkins [1]. A good estimation for the particle erosion and mass flux in the saltation layer is predicted, even though the profiles of mass flux and concentration within the transport layer are very thin and lowe

Two-dimensional numerical simulation of saltating particles using granular kinetic theory

Most granular flows at environmental conditions are unsteady and exhibit a complex physical behavior. Dune formation and migration in the desert are controlled not only by the flow of saltating particles over the sand bed, but also by turbulent atmospheric airflow. In fact, sediments are transported by the atmospheric airflow within a thin layer only a few centimeters above the sandy surface. These jumping particles reach a maximum sediment mass flux level at a certain delay time (known as the “saturation time”) after the initial movement by sliding and rolling begins. Unlike sediment transport in water where the particles are lifted by the turbulent suspension, the saltating particles are kept alive in the layer mainly due to particle-particle and particle-bed collisions. In order to model this Aeolian transport of sand, Jenkins and Pasini [1] proposed a two-fluid model (one-dimensional and steady state) using Granular Kinetic Theory (GKT) to describe the solid-phase stress. The present work extends the original idea of Jenkins and Pasini [1] by using a more robust model of GKT for the kinetic/collisional contributions to the solid-phase stress tensor, together with a friction model activated for sustained contacts between particles. In addition, a standard k-ε turbulence model for the air and a drag model for the interaction between the phases are employed. A rectangular 2D geometry was chosen with a logarithmic profile for the inlet air velocity, along with an initial amount of sand at rest in the lower part of the simulation domain, resembling the particle saltating flow commonly seen in the vertical middle plane within saltation wind tunnels. This model is validated with experimental data from Liu and Dong [2] and the results given by Pasini and Jenkins [1]. A good estimation for the particle erosion and mass flux in the saltation layer is predicted, even though the profiles of mass flux and concentration within the transport layer are very thin and lowe

Guidelines for measuring and reporting particle removal efficiency in fibrous media

Adopting standardized and reliable methodologies to accurately measure particle removal efficiency when developing fibrous materials for controlling airborne contamination is crucial. Here, we introduce well-established aerosol science and technology concepts often overlooked or misused in interdisciplinary studies developing new fibrous materials for particle filtration. We recommend best practices for experimental assessments and reporting to ensure a reliable evaluation of new airborne particle filtration media and technologies.Adopting standardized and reliable methodologies to accurately measure particle removal efficiency when developing fibrous materials for controlling airborne contamination is crucial. Here, the authors recommend best practices for experimental assessments and reporting to ensure a reliable evaluation of new airborne particle filtration media and technologies

The RP-Mdm2-p53 Pathway and Tumorigenesis

The dynamic processes of cell growth and division are under constant surveillance. As one of the primary “gatekeepers” of the cell, the p53 tumor suppressor plays a major role in sensing and responding to a variety of stressors to maintain cellular homeostasis. Recent studies have shown that inhibition of ribosomal biogenesis can activate p53 through ribosomal protein (RP)-mediated suppression of Mdm2 E3 ligase activity. Mutations in Mdm2 that disrupt RP binding have been detected in human cancers; however, the physiological significance of the RP-Mdm2 interaction is not completely understood. We generated mice carrying a single cysteine-to-phenylalanine substitution in the central zinc finger of Mdm2 (Mdm2C305F) that disrupts Mdm2’s binding to RPL11 and RPL5. Despite being developmentally normal and maintaining an intact p53 response to DNA damage, the Mdm2C305F mice demonstrate a diminished p53 response to perturbations in ribosomal biogenesis, providing the first in vivo evidence for an RP-Mdm2-p53 signaling pathway. Here we review some recent studies about RP-Mdm2-p53 signaling and speculate on the relevance of this pathway to human cancer

Self Assembled Clusters of Spheres Related to Spherical Codes

We consider the thermodynamically driven self-assembly of spheres onto the surface of a central sphere. This assembly process forms self-limiting, or terminal, anisotropic clusters (N-clusters) with well defined structures. We use Brownian dynamics to model the assembly of N-clusters varying in size from two to twelve outer spheres, and free energy calculations to predict the expected cluster sizes and shapes as a function of temperature and inner particle diameter. We show that the arrangements of outer spheres at finite temperatures are related to spherical codes, an ideal mathematical sequence of points corresponding to densest possible sphere packings. We demonstrate that temperature and the ratio of the diameters of the inner and outer spheres dictate cluster morphology and dynamics. We find that some N-clusters exhibit collective particle rearrangements, and these collective modes are unique to a given cluster size N. We present a surprising result for the equilibrium structure of a 5-cluster, which prefers an asymmetric square pyramid arrangement over a more symmetric arrangement. Our results suggest a promising way to assemble anisotropic building blocks from constituent colloidal spheres.Comment: 15 pages, 10 figure

Leading the Leaders: Embedded Educational Leadership Initiatives at the University of Windsor

This project explored the impact and scope of embedded educational leadership initiatives (EELIs) at the University of Windsor. EELIs are programs through which individual members of the campus community autonomously and often collaboratively develop and pursue educational improvement projects within their own contexts. Such initiatives are quite common at Canadian universities, and can include, for example, small grants schemes, teaching chairs, and peer observation of teaching networks. They serve many needs at universities, and are widely believed to be an effective approach to improving teaching and learning, driving innovation, building leadership capacity, and communicating the value institutions place on quality teaching. There has been comparatively little empirical research on the outcomes of these programs, and infrastructure for their evaluation for improvement of productivity or strategic alignment tends to be limited. Moreover, despite their strong potential, without a coordinated approach, it is hard to capitalize on the expertise created over time, to bring groups together to address joint concerns through collaborative initiatives, or to establish mechanisms to identify and further support projects whose expansion or duplication would be of benefit to other units on campus.https://scholar.uwindsor.ca/ctlreports/1002/thumbnail.jp

Análisis de las necesidades percibidas por mujeres migrantes latinoamericanas y sus hijos/as en Canarias

El presente estudio se centra en conocer las necesidades percibidas por las mujeres migrantes latinoamericanas que forman familias monoparentales con sus hijos/as en Canarias. Para ello, se ha llevado a cabo a través de una metodología cualitativa, enmarcada en la fenomenología, que corresponde con las entrevistas semiestructuradas (grupo de discusión). La investigación se llevó a cabo con un grupo de cuatro mujeres de orígenes venezolano, colombiano y argentino, profundizándose en diversos temas, como: la gestión de la vida familiar, social y laboral, la relación con el centro educativo y de salud, la interacción con los servicios sociales, ONG, etc. Tras la transcripción y categorización los datos, los resultados apuntan a que las familias monoparentales migrantes en Canarias, perciben una serie de necesidades de tipo económico, laboral, familiar y legal principalmente. También, que los recursos y apoyos de los que disponen son muy limitados y escasos, aunque refieren haber percibido ayudas de ayuntamientos, ONG, y otras instituciones, etc. Estos resultados evidencian la necesidad de contar con Políticas Sociales que apoyen a las madres migrantes latinoamericanas en su lucha diaria contra la pobreza y/o exclusión social en el país de acogida.This study focuses on the needs perceived by Latin American migrant women who form single-parent families with their children in the Canary Islands. For this purpose, it has been carried out through a qualitative methodology, framed in phenomenology, which corresponds to semi-structured interviews (discussion group). The research was carried out with a group of four women of Venezuelan, Colombian and Argentinean origins, exploring in depth various topics, such as: the management of family, social and work life, the relationship with the educational and health center, the interaction with social services, NGOs, etc. After transcribing and categorizing the data, the results indicate that migrant single-parent families in the Canary Islands perceive a series of needs, mainly of an economic, labor, family and legal nature. Also, that the resources and support available to them are very limited and scarce, although they report having received help from municipalities, NGOs, and other institutions, etc. These results show the need for public social policies to support Latin American migrant mothers in their daily struggle against poverty and/or social exclusion in the host country