Asthma and PM10

PM(10) (the mass of particles present in the air having a 50% cutoff for particles with an aerodynamic diameter of 10 μm) is the standard measure of particulate air pollution used worldwide. Epidemiological studies suggest that asthma symptoms can be worsened by increases in the levels of PM(10). Epidemiological evidence at present indicates that PM(10) increases do not raise the chances of initial sensitisation and induction of disease, although further research is warranted. PM(10) is a complex mixture of particle types and has many components and there is no general agreement regarding which component(s) could lead to exacerbations of asthma. However pro-inflammatory effects of transition metals, hydrocarbons, ultrafine particles and endotoxin, all present to varying degrees in PM(10), could be important. An understanding of the role of the different components of PM(10) in exacerbating asthma is essential before proper risk assessment can be undertaken leading to advice on risk management for the many asthmatics who are exposed to air pollution particles

Durability and inflammogenic impact of carbon nanotubes compared with asbestos fibres

<p>Abstract</p> <p>Background</p> <p>It has been suggested that carbon nanotubes might conform to the fibre pathogenicity paradigm that explains the toxicities of asbestos and other fibres on a continuum based on length, aspect ratio and biopersistence. Some types of carbon nanotubes satisfy the first two aspects of the fibre paradigm but only recently has their biopersistence begun to be investigated. Biopersistence is complex and requires <it>in vivo </it>testing and analysis. However durability, the chemical mimicking of the process of fibre dissolution using <it>in vitro </it>treatment, is closely related to biopersistence and more readily determined. Here, we describe an experimental process to determine the durability of four types of carbon nanotubes in simulated biological fluid (Gambles solution), and their subsequent pathogenicity <it>in vivo </it>using a mouse model sensitive to inflammogenic effects of fibres. The <it>in vitro </it>and <it>in vivo </it>results were compared with well-characterised glass wool and asbestos fibre controls.</p> <p>Results</p> <p>After incubation for up to 24 weeks in Gambles solution, our control fibres were recovered at percentages consistent with their known <it>in vitro </it>durabilities and/or <it>in vivo </it>persistence, and three out of the four types of carbon nanotubes tested (single-walled (CNT_SW) and multi-walled (CNT_TANG2, CNT_SPIN)) showed no, or minimal, loss of mass or change in fibre length or morphology when examined by electron microscopy. However, the fourth type [multi-walled (CNT_LONG1)] lost 30% of its original mass within the first three weeks of incubation, after which there was no further loss. Electron microscopy of CNT_LONG1samples incubated for 10 weeks confirmed that the proportion of long fibres had decreased compared to samples briefly exposed to the Gambles solution. This loss of mass and fibre shortening was accompanied by a loss of pathogenicity when injected into the peritoneal cavities of C57Bl/6 mice compared to fibres incubated briefly. CNT_SWdid not elicit an inflammogenic effect in the peritoneal cavity assay used here.</p> <p>Conclusions</p> <p>These results support the view that carbon nanotubes are generally durable but may be subject to bio-modification in a sample-specific manner. They also suggest that pristine carbon nanotubes, either individually or in rope-like aggregates of sufficient length and aspect ratio, can induce asbestos-like responses in mice, but that the effect may be mitigated for certain types that are less durable in biological systems. Results indicate that durable carbon nanotubes that are either short or form tightly bundled aggregates with no isolated long fibres are less inflammogenic in fibre-specific assays.</p

Critical Mentoring in Urban Contexts: Culturally Embracing School-Community Collaborative Partnerships

Mentoring programs regularly discuss the positive academic, developmental, and socioemotional outcomes for young people who are being supported. Research around school-based mentoring shows that it has the potential to increase mentees’ self-perception, interest in academic pursuit, motivation to learn, and academic performance, prosocial attachments and trust, as well as their interpersonal skills and their ability to deal with social and emotional difficulties. However, much less attention is paid to preparing mentors who can support students, particularly marginalized and minoritized students of color, in an asset-based, equity-framed manner. This research study evaluates fifteen school-based mentors (the Heinz Fellows) who work for the Center for Urban Education at the University of Pittsburgh, supporting students in Pittsburgh Public Schools in the Hill District. Using the Opportunity Gap Framework developed by Milner (2010, 2012) to structure the program, train and develop the mentors, and evaluate findings, pre-and post-survey results showed that the Fellows’ perceived attitudes, beliefs, thoughts, and dispositions as a group increased in alignment with the Opportunity Gap Framework. These perceived mindset shifts occurred due to five major activities in the program: (1) critical race reflection, (2) context observations of cultural discontinuity, (3) critical institutionalism, (4) critical mentoring practices, and (5) exposure to research and lectures around equity and culturally relevant practices

Formal specification of QoS properties

We describe the specification of communication services, with special emphasis being placed on the use of the Temporal Logic of Actions (TLA) to describe the behaviours involved. We show how, startingfrom Message Sequence Charts, this temporal logic may be used to describe The Joint Viewing and Tele Operating Service (JVTOS) and its associated functions; and so lead on to the specification of QoS parameters. We discuss the approach that was taken to determine the exact nature of the Quality of Service parameters, and how the method may be used to extend the specification, and probe further aspects of the services and protocols involved

Persistent inflammation and impaired chemotaxis of alveolar macrophages on cessation of dust exposure

Rats were exposed by inhalation to coal mine dust, titanium dioxide, or quartz. The magnitude of the consequent inflammatory response was assessed by counting numbers and types of leukocytes in the bronchoalveolar lavage fluid. The magnitude of the inflammatory response reflected the toxicity of the dusts, with quartz eliciting the greatest recruitment of inflammatory leukocytes, coal mine dust less than quartz, and titanium dioxide eliciting no inflammation. To assess the persistence of the inflammation, groups of rats were maintained in room air for 30 or 60 days after cessation of dust exposure and then numbers of leukocytes were assessed. Bronchoalveolar leukocytes in rats exposed to coal mine dust were reduced after exposure, but in the quartz-exposed rats the numbers increased with time after exposure. The chemotactic responses of bronchoalveolar leukocytes from rats inhaling coal mine dust and quartz were reduced and remained so after a 30-day recovery period. Their reduced ability to chemotact did not fully prevent macrophages from leaving the bronchoalveolar region of dust-exposed rats. However, it is likely that the delayed removal of inflammatory leukocytes with the potential to injure the lung tissue may contribute to septal damage and so contribute to the pathogenesis of pneumoconiosis

Improved crystal structure solution from powder diffraction data by the use of conformational information

The effect of introducing conformational information to the DASH implementation of crystal structure determination from powder diffraction data is investigated using 51 crystal structures, with the aim of allowing increasingly complex crystal structures to be solved more easily. The findings confirm that conformational information derived from the Cambridge Structural Database is indeed of value, considerably increasing the chances of obtaining a successful structure determination. Its routine use is therefore encouraged

Improved performance of crystal structure solution from powder diffraction data through parameter tuning of a simulated annealing algorithm

Significant gains in the performance of the simulated annealing algorithm in the DASH software package have been realised by using the irace automatic configuration tool to optimise the values of three key simulated annealing parameters. Specifically, the success rate in finding the global minimum in intensity chi squared space is improved by up to an order of magnitude. The general applicability of these revised simulated annealing parameters is demonstrated using the crystal structure determinations of over 100 powder diffraction data sets

Prototype performance evaluation of multimedia service components

This paper deals with a formal approach for decomposition and description of multimedia service components and their performance analysis. Our approach is based on the Temporal Logic of Actions (TLA) specifications. A TLA based specification of multimedia components is transformed into process prototypes described with the SPIMS (SICS Protocol Implementation Measurement System) application language. The multimedia component prototype derived in this way is then evaluated with the SPIMS tool for different QoS parameters. The proposed approach using TLA based specifications, transformations in SPIMS application prototypes, and performance analysis provides the background for an computer based system for test specification and performance analysis which is currently under development. We present and discuss practical test scenarios derived from the proposed method for performance analysis of the Audio-Visual Communication (AVC)component of the Joint-Viewing and Tele-Operation Service (JVTOS). The multimedia test scenarios shown use the TCP/IP and XTP protocols on top of FORE ATM networks

Free radical activity of industrial fibers: role of iron in oxidative stress and activation of transcription factors

We studied asbestos, vitreous fiber (MMVF10), and refractory ceramic fiber (RCF1) from the Thermal Insulation Manufacturers' Association fiber repository regarding the following: free radical damage to plasmid DNA, iron release, ability to deplete glutathione (GSH), and activate redox-sensitive transcription factors in macrophages. Asbestos had much more free radical activity than any of the man-made vitreous fibers. More Fe3+ was released than Fe2+ and more of both was released at pH 4.5 than at pH 7.2. Release of iron from the different fibers was generally not a good correlate of ability to cause free radical injury to the plasmid DNA. All fiber types caused some degree of oxidative stress, as revealed by depletion of intracellular GSH. Amosite asbestos upregulated nuclear binding of activator protein 1 transcription factor to a greater level than MMVF10 and RCF1; long-fiber amosite was the only fiber to enhance activation of the transcription factor nuclear factor kappa B (NF kappa B). The use of cysteine methyl ester and buthionine sulfoximine to modulate GSH suggested that GSH homeostasis was important in leading to activation of transcription factors. We conclude that the intrinsic free radical activity is the major determinant of transcription factor activation and therefore gene expression in alveolar macrophages. Although this was not related to iron release or ability to deplete macrophage GSH at 4 hr, GSH does play a role in activation of NF kappa B