Fine Partical and Toxic Metal Emissions From the Combustion of Sewage Sludge/Coal Mixtures: A Systematic Assessment

This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and pulverized coal. The objective was to determine potential tradeoffs between CO{sub 2} mitigation through using a CO{sub 2} neutral fuel, such as municipal sewage sludge, and the emergence of other potential problems such as the emission of toxic fly ash particles. The work led to new insight into mechanisms governing the partitioning of major and trace metals from the combustion of sewage sludge, and mixtures of coal and sewage sludge. The research also showed that the co-combustion of coal and sewage sludge emitted fine particulate matter that might potentially cause greater lung injury than that from the combustion of either coal alone or municipal sewage sludge alone. The reason appeared to be that the toxicity measured required the presence of large amounts of both zinc and sulfur in particles that were inhaled. MSS provided the zinc while coal provided the sulfur. Additional research showed that the toxic effects could most likely be engineered out of the process, through the introduction of kaolinite sorbent downstream of the combustion zone, or removing the sulfur from the fuel. These results are consequences of applying ''Health Effects Engineering'' to this issue. Health Effects Engineering is a new discipline arising out of this work, and is derived from using a collaboration of combustion engineers and toxicologists to mitigate the potentially bad health effects from combustion of this biomass fuel

GenQ: Automated Question Generation to Support Caregivers While Reading Stories with Children

When caregivers ask open--ended questions to motivate dialogue with children, it facilitates the child's reading comprehension skills.Although there is scope for use of technological tools, referred here as "intelligent tutoring systems", to scaffold this process, it is currently unclear whether existing intelligent systems that generate human--language like questions is beneficial. Additionally, training data used in the development of these automated question generation systems is typically sourced without attention to demographics, but people with different cultural backgrounds may ask different questions. As a part of a broader project to design an intelligent reading support app for Latinx children, we crowdsourced questions from Latinx caregivers and noncaregivers as well as caregivers and noncaregivers from other demographics. We examine variations in question--asking within this dataset mediated by individual, cultural, and contextual factors. We then design a system that automatically extracts templates from this data to generate open--ended questions that are representative of those asked by Latinx caregivers

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

On inhalation health effects of combustion generated ash aerosol particles

Epidemiological studies have consistently shown an association between elevated quantities of ambient airborne particulate matter (PM) and acute health effects. The focus here is on health effects of primary PM and is intended to provide insight into the roles of particulate speciation on inhalation toxicity. PM considered consisted of combustion generated ash particles from (1) coal, (2) coal/municipal sewage sludge (MSS) mixture, (3) MSS burned with natural gas assist, (4) coal/refuse derived fuel (unstaged and staged), (5) residual fuel oil (ROFA), (6) combustion generated zinc particles, with and without sulfur, and (7) combustion generated zinc which had been sequestered by sorbent particles. In each case, health effects were investigated in-vivo by direct inhalation by a mouse model. An aerosol re-suspension system that produces aerosol concentrations of ∼1000μg/m³ was designed, and characterized. Particles were characterized with respect to size, elemental composition, leachability, and pH of supernatant. Measured alterations in lung permeability, along with pulmonary functions were used as measurements of lung injury. One-hour exposures were conducted for periods lasting from 1 to 24 days. The validity of assumptions used in the lung permeability measurement technique, was explored using a new mathematical model. In-vivo results indicate two types of lung permeability behavior. Inhalation of ash particles from coal, MSS, residual fuel oil, ZnO, and Zn sequestered by kaolinite caused an initial decrease in lung permeability followed by a "recovery" to control mice values (Type 1 behavior). In contrast, the exposure to ash from coal plus MSS, coal plus RDF, and zinc plus sulfur, triggered an increase in lung permeability (Type 2 behavior). This work demonstrates the value of health effects engineering, combining both combustion engineering and toxicology. Particle speciation is extremely important and sulfated zinc has been identified as a "bad actor". Ash aerosol from either coal or MSS combustion alone produces Type 1 behavior in lung permeability, while ash aerosol from combustion of a mixture of coal and MSS produces Type 2 behavior. The high temperature capture of zinc vapor on kaolinite sorbent greatly mitigates lung injury allowing permeability behaviors to change from Type 2 to Type 1

Microfluidic systems for biosensing

In the past two decades, Micro Fluidic Systems (MFS) have emerged as a powerful tool for biosensing, particularly in enriching and purifying molecules and cells in biological samples. Compared with conventional sensing techniques, distinctive advantages of using MFS for biomedicine include ultra-high sensitivity, higher throughput, in-situ monitoring and lower cost. This review aims to summarize the recent advancements in two major types of micro fluidic systems, continuous and discrete MFS, as well as their biomedical applications. The state-of-the-art of active and passive mechanisms of fluid manipulation for mixing, separation, purification and concentration will also be elaborated. Future trends of using MFS in detection at molecular or cellular level, especially in stem cell therapy, tissue engineering and regenerative medicine, are also prospected