Responses to COVID-19 in the US build on a 100-year history of state and local public health partnerships

Efforts to tackle the COVID-19 pandemic have not just come from the US federal government – state and local governments have played an important role, too, including by collaborating with non-governmental organizations. Matthew Purcell writes that these partnerships are nothing new: like Partners in Health today, organizations such as the Rockefeller Foundation aided and managed public health campaigns in the US South from 1910 to 1930

Feasibility of using computational fluid dynamics for analysis of flow in an orbiting dish.

The oscillatory flow provided by an orbital shaker table correlates somewhat to the pulsatile flow seen in the human vasculature. This parallel allows for the use of the orbital shaker table in a large range of biomedical research. However, the fluid dynamics is not well characterized in this system. This research employed the computational fluid dynamics (CFD) package FLUENT in an effort to better understand the fluid dynamics in an orbiting dish. This work was performed at low resolution as a first attempt to examine the fluid flow characteristics. The first objective was to determine the time required to reach a steady state. This was found to occur within four orbits of the dish. The shear stress on the bottom surface of an orbital dish was then investigated and compared to previously published scalar functions. An equation used in two cases by Ley et al. (1989) determined shear to be 2.76 dyne/cm2 and 3.12 dyne/cm2 respectively. These systems had Stokes Numbers of 2 and 2.5, Froude Numbers of 0.7 and 0.8 and Slope Ratios of 0.4 and 0.3 respectively. . When modeled in FLUENT the cases showed the magnitude of shear stress in the center of the dish to be 0.67 dyne/cm2 and 1.11 dyne/cm2 respectively. The average shear stress on the bottom of the dish for the same cases was determined to be 0.39 dyne/cm2 and 0.85 dyne/cm2 respectively. More revealing, the shear was found to be uneven across the bottom of the dish with maximum shear near the peak of the fluid wave. Next, cases were simulated across ranges of dimensionless Stokes Number, Froude Number, and slope ratio at low resolution to determine the feasibility of using FLUENT to observe transitions. Each case was run at a constant Reynolds Number of 100 to maintain laminar flow. A Stokes number transition is evidenced by a lag in the location of the fluid peak relative to the location of the dish. When a gap in the leading edge of the fluid is observed, a Froude number transition has occurred. A large free surface slope resulting in a dry area forming on the bottom of the dish is indicative of a Slope Ratio transition. These transitions were positively identified at low resolution when changing one dimensionless number while keeping the others constant

Soil biotic and abiotic conditions negate invasive species performance in native habitat

Background: Most studies on plant invasion consider the enemy release hypothesis when analyzing native habitats. However, the lower performance of invasive species in the native habitats can be the result of unfavorable soil conditions in the native habitats. While soil biotic and abiotic factors have a potential to restrict the growth of invasive species in their native habitats, our understanding of belowground environment of invasive species in their native habitats is very limited. In this study, we analyzed soil characteristics associated with an exotic invasive plant, Old World Climbing Fern (Lygodium microphyllum), in its native habitat in Australia and the recipient habitat in South Florida. Rhizosphere soil samples from both habitats were analyzed for soil physical, chemical and biological characteristics. Results: Soil characteristics in the recipient habitats were significantly different compared to those in the native habitats. Soil samples from the native habitat had low soil pH, and high concentrations of elements such as aluminum and zinc which are phytotoxic in acidic soil environments. Additionally, mycorrhizal fungi spores were more diverse in the recipient habitat in Florida compared to the native habitat in Australia. Conclusion: Overall, our results indicate that growth of an invasive plant in its native habitats could be restricted by the toxic effects associated with strong soil acidity. Results from this study indicate that invasive plants not only escape from their natural herbivores but also from toxic soil environment in their native habitats

Data on foliar nutrient concentration of invasive plants in the recipient habitat and their native habitat

Higher foliar nitrogen concentration in plants is often attributed to higher biomass assimilation and subsequently higher plant growth rate. To understand the underlying mechanism of extensive growth rate of an invasive plant, Old World climbing fern (Lygodium microphyllum), we analyzed the leaf tissue samples from the native and invaded habitats. In each habitat we selected 3 different locations with varying habitat characteristics (soil type, land use history and coexisting vegetation). Plant aboveground tissue collected from each site were analyzed for macro and micro nutrients. Total C and N were measured with a Truspec CN Analyzer. Total Ca, Fe, Mg, K, Mn, and P in plant tissue samples were measured using inductively coupled plasma mass spectrometry (ICP eMS). Here we present the difference in foliar nutrient concentration of invasive plant species in their native habitats and invaded habitats

Watchdog or Lapdog: Limits of African Media Coverage of the Extractive Sector

The purpose of this study is to evaluate the quality of African media coverage of the extractive industries. This sector plays prominently on the African political, economic, social and journalistic landscape, yet coverage of these industries remains a challenge for African journalists. The financial and technical aspects of the extractive sector are complex, and both governments and companies often have a vested interest in withholding information from journalists. Many reporters lack sufficient training, resources and/or journalistic freedom to publish accurate, well‐researched, in‐depth coverage. As a result, what are arguably some of the most critical industries on the continent operate in relative freedom from public scrutiny. By making a careful study of African media coverage of the extractive sector in three countries, this report hopes to identify key strengths and weaknesses in extractive industry reporting as well as opportunities for media support and the expansion or revision of current media training efforts. The discovery of oil in Uganda in 2006 and in Ghana in 2007 brought both a great deal of excitement and a considerable level of worry to these countries. While extractive resources (oil, gas and mining) are a leading source of wealth for many African countries, this wealth often leads to corruption and conflict. In fact, countries with abundant natural resources tend to fall below less resource‐wealthy countries in terms of human development, a paradox economist Richard Auty and subsequent researchers have labeled the "resource curse." This report is based on two premises: first, that if Africans are to benefit from the immense resource stores that lie beneath their soil, great efforts must be made toward transparency in how these resources are handled. Second, the call for transparency cannot come from non‐governmental organizations and individual political leaders alone. The African media have a critical responsibility to push toward government and corporate openness in the extractive industries. African media have made great strides since the latter half of the twentieth century, but they continue to struggle to fulfill their role as society's watchdog. Instead of keeping governments in check through enterprising stories or investigative pieces, most African media have instead been leashed by a confluence of factors. Lack of resources, government intimidation and interference, media ownership, revenue structures and declining educational quality all make the job of the African journalist difficult. To mitigate some of these constraints, local and international non‐governmental organizations (NGOs), media outlets and in some cases government agencies are training journalists to more fully understand the intricacies of the areas that they cover

Validation of an integrated pressure level measured earmold wideband real-ear-to-coupler difference measurement

Objective: To validate measurement of predicted earmold wideband real-ear-to-coupler difference (wRECD) using an integrated pressure level (IPL) calibrated transducer and the incorporation of an acoustically measured tubing length correction. Design: Unilateral earmold SPL wRECD using varied hearing aid tubing length and the proposed predicted earmold IPL wRECD measurement procedure were completed on all participants and compared. Study Sample: 22 normal hearing adults with normal middle ear status were recruited. Results: There were no clinically significant differences between probe-microphone and predicted earmold IPL wRECD measurements between 500 and 2500 Hz. Above 5000 Hz, the predicted earmold IPL wRECD exceeded earmold SPL wRECDs due to lack of standing wave interference. Test-retest reliability of IPL wRECD measurement exceeded the reliability of earmold SPL wRECD measurement across all assessed frequencies, with the greatest improvements in the high frequencies. The acoustically measured tubing length correction largely accounted for acoustic effects of the participant’s earmold. Conclusions: IPL-based measurements provide a promising alternative to probe-microphone earmold wRECD procedures. Predicted earmold IPL wRECD is measured without probe-microphone placement, agrees well with earmold SPL wRECDs and is expected to extend the valid bandwidth of wRECD measurement

Supercritical fluid foaming : a novel route to polymeric allografts?

There is a growing need for synthetic bone graft materials, which is particularly apparent for procedures requiring impaction bone grafting (IBG), such as revision hip arthroplasty. Currently allograft bone is used that has limited supply and associated risks of transmission of infectious agents. Porous bioresorbable polymeric scaffolds can be created using supercritical carbon dioxide (scCO2). This thesis investigated the use of these scaffolds for impaction bone grafting procedures. Building on previous research within the literature poly(D,L-lactide) (PDLLA) and poly(D,L-lactide-co-glycolide) (PDLLGA) scaffolds of high molecular weight (100 kDa) were investigated for this use. Scaffolds were milled using a standard bone mill and impacted to create porous milled chips of bioresorbable scaffolds and impacted for mechanical shear testing and biocompatibilities. The impaction process used forces equivalent to those experienced during IBG. In vitro cell experiments were used to assess the proliferation and osteoblastic differentiation of mesenchymal stem cells (MSCs) on impacted scaffolds to identify the most promising scaffold compositions. These compositions included pure polymer and polymer:HA microparticle composites. Further experiments using animals (murine and ovine) were then used to investigate the in vivo performance of the scaffolds. A critical sized ovine femoral condyle defect established the osteoinductive and osteoconductive potentials of milled scCO2 foamed PDLLA + 10 wt.% hydroxyapatite (HA) microparticle scaffolds in vivo. The scale-up potential of scCO2 foaming of bioresorbable scaffolds was established using a 1 L vessel. Scaffolds scCO2 foamed using either a 60 ml autoclave or a 1 L vessel were characterised using scanning electron microscopy and micro computed tomography. Scaffolds from different batches were characterised and compared to ensure process repeatability was accounted for. The final chapter investigated differences in the osteoblastic differentiation of MSCs on PDLLA and PDLLGA scaffolds observed in experiments at the start of the study. Spincoated and dipcoated flat films of PDLLA, PDLLGA, and PDLLA:PDLLGA (50:50) were used for in vitro cell culture to remove the effect of morphological differences that affected scCO2 foamed scaffold experiments. Additionally, this chapter investigated the effect of the form of HA using HA nanoparticles andHA microparticles in scCO2 foamed PDLLA:HA composites for in vitro studies

Supercritical fluid foaming : a novel route to polymeric allografts?

There is a growing need for synthetic bone graft materials, which is particularly apparent for procedures requiring impaction bone grafting (IBG), such as revision hip arthroplasty. Currently allograft bone is used that has limited supply and associated risks of transmission of infectious agents. Porous bioresorbable polymeric scaffolds can be created using supercritical carbon dioxide (scCO2). This thesis investigated the use of these scaffolds for impaction bone grafting procedures. Building on previous research within the literature poly(D,L-lactide) (PDLLA) and poly(D,L-lactide-co-glycolide) (PDLLGA) scaffolds of high molecular weight (100 kDa) were investigated for this use. Scaffolds were milled using a standard bone mill and impacted to create porous milled chips of bioresorbable scaffolds and impacted for mechanical shear testing and biocompatibilities. The impaction process used forces equivalent to those experienced during IBG. In vitro cell experiments were used to assess the proliferation and osteoblastic differentiation of mesenchymal stem cells (MSCs) on impacted scaffolds to identify the most promising scaffold compositions. These compositions included pure polymer and polymer:HA microparticle composites. Further experiments using animals (murine and ovine) were then used to investigate the in vivo performance of the scaffolds. A critical sized ovine femoral condyle defect established the osteoinductive and osteoconductive potentials of milled scCO2 foamed PDLLA + 10 wt.% hydroxyapatite (HA) microparticle scaffolds in vivo. The scale-up potential of scCO2 foaming of bioresorbable scaffolds was established using a 1 L vessel. Scaffolds scCO2 foamed using either a 60 ml autoclave or a 1 L vessel were characterised using scanning electron microscopy and micro computed tomography. Scaffolds from different batches were characterised and compared to ensure process repeatability was accounted for. The final chapter investigated differences in the osteoblastic differentiation of MSCs on PDLLA and PDLLGA scaffolds observed in experiments at the start of the study. Spincoated and dipcoated flat films of PDLLA, PDLLGA, and PDLLA:PDLLGA (50:50) were used for in vitro cell culture to remove the effect of morphological differences that affected scCO2 foamed scaffold experiments. Additionally, this chapter investigated the effect of the form of HA using HA nanoparticles andHA microparticles in scCO2 foamed PDLLA:HA composites for in vitro studies