Measurement, Modeling, and Mitigation of Lead Impacts from General Aviation

Airborne lead (Pb) has been regulated as a criteria pollutant by the United States Environmental Protection Agency (EPA) since the Clean Air Act and its amendments in the 1970s. During the 1970s, atmospheric Pb emissions were dominated by the combustion of leaded automobile fuel and metals manufacturing. Over time, those emissions have decreased greatly and according to the EPA the largest emitter of Pb today is piston-engine aircraft. Additionally, in 2008 the EPA reduced the National Ambient Air Quality Standard (NAAQS) for Pb by an order of magnitude. These combined factors served as the impetus for further study of general aviation Pb emissions by the EPA, local and regional air planning agencies, and airports. This dissertation is focused on characterizing Pb impacts at and around general aviation airports because of piston-engine aircraft activity. It includes a detailed analysis of Pb emissions and concentrations by both measurement and modeling. On-site particulate matter (PM) sampling was conducted at three general aviation airports across the United States with varying size, meteorological, and layout characteristics. Those airports were Richard Lloyd Jones Jr. Airport (RVS) in Tulsa, OK, Centennial Airport (APA) in Denver, CO, and Santa Monica Airport (SMO) in Santa Monica, CA. Airborne PM samples collected at these airports were digested and analyzed for Pb by inductively coupled plasma-mass spectrometry (ICP-MS) and a subset of samples were analyzed by X-ray fluorescence (XRF) to examine both Pb and Bromine (Br). Measurement data were used to characterize Pb at airports by examining differences in Pb concentrations at sampling locations upwind and downwind of piston-engine aircraft activity on the airport footprints. Specific analyses included upwind-downwind differences in total Pb concentrations, differences in Pb-Br correlations for samples with predicted high and low aircraft emissions impacts, and differences in Pb isotope ratios measured in the high and low impact samples. The analysis showed that Pb-Br correlation and especially Pb isotope ratios, could serve as markers for identifying Pb impacts from aircraft. Measured Pb concentrations were also used to validate the modeling performed as part of this work. Further analysis of Pb impacts was conducted by performing air dispersion modeling of Pb emissions at airports. Modeling of Pb impacts is critical because Pb measurements are usually only collected at a single or limited number of locations at or near an airport. Initially, Pb emissions at APA were modeled using the Federal Aviation Administration’s (FAA) Emission and Dispersion Modeling System (EDMS), without having detailed information about aircraft activity at the airport. Subsequently, field campaigns were conducted at RVS, APA, and SMO to collect detailed on-site activity data and to characterize the aircraft fleet. These data were collected concurrently with the on-site Pb sampling. The airport-specific data collection was used to generate a spatially and temporally resolved emission inventory which was used as input to the EPA’s AERMOD air dispersion model to estimate Pb concentration fields at and around each of the three airports. Modeled concentrations agreed well with measured values at RVS and SMO, while comparisons at APA were inferior but still acceptable by conventional air quality modeling permeance metrics. The modeling was also used to determine the aircraft operations most significantly contributing to Pb hotspots. The on-site data collection and air quality modeling framework was then applied to a fourth airport, Palo Alto Airport (PAO) in Palo Alto, CA. Data collection was conducted over a shorter period of time than the other airports. The modeled results at PAO showed excellent comparison to on-site concentrations measured by the local air agency, even though the data collection, other than total daily activity, did not occur at the same time as the modeled period. The model setups for RVS, SMO, and PAO were then used to evaluate two mitigation strategies: moving some activity areas away from others to reduce converging emissions; and replacing leaded aviation gasoline with motor vehicle gasoline in planes that are certified to use it. Moving activity areas significantly reduced maximum Pb concentrations at RVS and SMO with a smaller reduction at PAO, while using motor vehicle gasoline significantly reduced concentrations across the full airport footprints at all three airports

Long Range Forces from Two Neutrino Exchange Revisited

The exchange of two massless neutrinos gives rise to a long range force which couples to weakly charged matter. As has been noted previously in the literature, the potential for this force is \VN \propto G_{F}^2 / r^5 with monopole-monople, spin-spin and more complicated interactions. Unfortunately, this is far too small to be observed in present day experiments. We calculate \VN explicitly in the electroweak theory, and show that under very general assumptions forces arising from the exchange of two massless fermions can at best yield $1 / r^5$ potentials.Comment: 5 pages + 1 figure (not included), UFIFT-HEP-92-28/HUTP-92-A04

Developmental ECM Sculpting: Laying It Down and Cutting It Up

In mammals, proteolytic remodeling of the embryonic extracellular matrix (ECM) controls morphogenesis, but the key players remain elusive. Two recent reports identify new roles for metalloproteinases belonging to the MT-MMP and ADAMTS families in branching morphogenesis and interdigital web regression

Characterization of a unique technique for culturing primary adult human epithelial progenitor/“stem cells”

Abstract Background Primary keratinocytes derived from epidermis, oral mucosa, and urothelium are used in construction of cell based wound healing devices and in regenerative medicine. This study presents in vitro technology that rapidly expands keratinocytes in culture by growing monolayers under large volumes of serum-free, essential fatty acid free, low calcium medium that is replaced every 24 hrs. Methods Primary cell cultures were produced from epidermal skin, oral mucosa and ureter by trypsinization of tissue. Cells were grown using Epilife medium with growth factors under high medium volumes. Once densely confluent, the keratinocyte monolayer produced cells in suspension in the overlying medium that can be harvested every 24 hrs. over a 7–10 day period. The cell suspension (approximately 8 X 105 cells/ml) is poured into a new flask to form another confluent monolayer over 2–4 days. This new culture, in turn produced additional cell suspensions that when serially passed expand the cell strain over 2–3 months, without the use of enzymes to split the cultures. The cell suspension, called epithelial Pop Up Keratinocytes (ePUKs) were analyzed for culture expansion, cell size and glucose utilization, attachment to carrier beads, micro-spheroid formation, induction of keratinocyte differentiation, and characterized by immunohistochemistry. Results The ePUKs expanded greatly in culture, attached to carrier beads, did not form micro-spheroids, used approximately 50% of medium glucose over 24 hrs., contained a greater portion of smaller diameter cells (8–10 microns), reverted to classical appearing cultures when returned to routine feeding schedules (48 hrs. and 15 ml/T-75 flask) and can be differentiated by either adding 1.2 mM medium calcium, or essential fatty acids. The ePUK cells are identified as cycling (Ki67 expressing) basal cells (p63, K14 expressing). Conclusions Using this primary culture technique, large quantities of epithelial cells can be generated without the use of the enzyme trypsin to split the cultures. The cells are small in diameter and have basal cell progenitor/”stem” (P/SC) cell characteristics induced by daily feeding with larger than normal medium volumes. The ePUK epithelial cells have the potential to be used in regenerative medicine and for basic studies of epithelia P/SC phenotype.http://deepblue.lib.umich.edu/bitstream/2027.42/112344/1/12895_2011_Article_127.pd

Evaluation of Transplanted Tissue-Engineered Oral Mucosa Equivalents in Severe Combined Immunodeficient Mice

The aim of this study was to determine the optimal stage of development at which transplant human ex vivo-produced oral mucosa equivalents (EVPOMEs) in vivo. EVPOMEs were generated in a serum-free culture system, without the use of an irradiated xenogeneic feeder layer, by seeding human oral keratinocytes onto a human cadaveric dermal equivalent, AlloDerm. EVPOMEs were cultured for 4 days submerged and then for 7 or 14 days at an air-liquid interface to initiate stratification before transplantation into SCID mice. AlloDerm, without epithelium, was used as a control. Mice were killed on days 3, 10, and 21 posttransplantation. Epithelium of the transplanted EVPOMEs was evaluated with the differentiation marker keratin 10/13. Dermal microvessel ingrowth was determined by immunohistochemistry with a mouse vascular marker, lectin binding from Triticum vulgaris. The presence and stratification of the epithelium were correlated with revascularization of the underlying dermis. The microvessel density of AlloDerm without epithelium was less than that of EVPOMEs with an epithelial layer. Microvessel density of the dermis varied directly with the degree of epithelial stratification of the EVPOMEs. The EVPOMEs cultured at an air-liquid interface for 7 days had the optimal balance of neoangiogenesis and epithelial differentiation necessary for in vivo grafting.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63269/1/107632703762687645.pd

Fabrication of Large Size Ex Vivo-Produced Oral Mucosal Equivalents for Clinical Application

The soft tissue reconstruction of significant avulsed and/or surgically created tissue defects requires the ability to manufacture substantial soft tissue constructs for repair of the resulting wounds. In this study, we detail the issues that need to be addressed in upsizing the manufacture of larger tissue-engineered devices (ex vivo-produced oral mucosa equivalent [EVPOME]) in vitro from a methodology previously used for smaller constructs. The larger-sized EVPOME, consisting of autologous human oral keratinocytes and a dermal substitute, AlloDerm?, was fabricated for the purpose of reconstructing large clinical defects. Regulated as an autologous somatic cell therapy product, the fabrication process abided by current Good Manufacturing Practices and current Good Tissue Practices as required by the Center for Biologics Evaluation and Research (CBER) of the United States Food and Drug Administration (FDA). Successful fabrication of large EVPOMEs utilized a higher cell seeding density (5.3?105 cells/cm2) with a relatively thinner AlloDerm, ranging from 356.6 to 508.0??m in thickness. During the air?liquid interface culture, the thickness of the scaffold affected the medium diffusion rate, which, in turn, resulted in changes of epithelial stratification. Histologically, keratinocyte progenitor (p63), proliferation (Ki-67), and late differentiation marker (filaggrin) expression showed differences correlating with the expression of glucose transporter-1 (GLUT1) in the EVPOMEs from the thickest (550?1020??m) to the thinnest (228.6?330.2??m) AlloDerm scaffold. Glucose consumption and 2-deoxyglucose (2DG) uptake showed direct correlation with scaffold thickness. The scaffold size and thickness have an impact on the cellular phenotype and epithelial maturation in the manufacturing process of the EVPOME due to the glucose accessibility influenced by the diffusion rate. These outcomes provide basic strategies to manufacture a large-sized, healthy EVPOME graft for reconstructing large mucosa defects.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140251/1/ten.tec.2014.0600.pd

Establishing Peer Recovery Support Services to Address the Central Appalachian Opioid Epidemic: The West Virginia Peers Enhancing Education, Recovery, and Survival (WV PEERS) Pilot Program

Introduction: Central Appalachia has been disproportionately affected by the opioid epidemic and overdose fatalities. We developed West Virginia Peers Enhancing Education, Recovery, and Survival (WV PEERS), a program based on peer recovery support, to engage individuals using opioids and link them with a range of services. Methods: Community partners providing services to individuals with opioid use disorder (OUD) were identified and collaborations were formalized using a standardized memorandum of understanding. The program was structured to offer ongoing peer recovery support specialist (PRSS) services, not just a one-time referral. A website and cards describing the WV PEERS program were developed and disseminated via community partners and community education sessions. Results: Overall, 1456 encounters with individuals with OUD (mean= 2 encounters per individual) occurred in a variety of community settings over 8 months. The majority of referrals were from harm reduction programs. Overall, 63.9% (n=931) of individuals served by WV PEERS accessed services for substance use disorders and/or mental health problems. Over half (52.3%; n = 487) of individuals entered substance use and/or mental health treatment, and nearly a third (30.4%; n = 283) remained in treatment over six months. Implications: Using the WV PEERS model, PRSSs effectively engaged and linked individuals with OUD to mental health and substance use treatment in rural central Appalachia. Future research is needed to determine whether these services reduce the risk of overdose mortality

Analyzing Data from Multivariate Directed Graphs: An Application to Social Networks

1 online resource (PDF, 29 pages

Extracellular matrixâ based scaffolding technologies for periodontal and periâ implant soft tissue regeneration

The present article focuses on the properties and indications of scaffoldâ based extracellular matrix (ECM) technologies as alternatives to autogenous soft tissue grafts for periodontal and periâ implant plastic surgical reconstruction. The different processing methods for the creation of cellâ free constructs resulting in preservation of the extracellular matrices influence the characteristics and behavior of scaffolding biomaterials. The aim of this review is to discuss the properties, clinical application, and limitations of ECMâ based scaffold technologies in periodontal and periâ implant soft tissue augmentation when used as alternatives to autogenous soft tissue grafts.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153617/1/jper10427.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153617/2/jper10427_am.pd