Terrestrial Exchange of Atmospheric Metals: Insights from Fallout Radionuclides

Forests mediate the exchange of gases and particulate matter (PM2.5 and PM10) between terrestrial ecosystems and the atmosphere over 30% of global land area. Because forest foliage efficiently absorbs PM with persistent pollutants including metals Pb and Hg, as well as CO2 and gaseous elemental mercury (GEM), this exchange profoundly influences the composition of the atmosphere as well as terrestrial biogeochemical cycles. The processes by which PM is absorbed remain enigmatic, however, due to the complexity of micrometeorological physics and submicron physical scale of the interaction. Here, measurements of fallout radionuclides (FRNs) beryllium-7 and lead-210, which are quintessential tracers of PM but also radioactive and decay with known rates, provide insights into fundamental questions regarding the role of wet vs dry process in PM deposition, the strength of PM retention by forest canopies, and the timescales over which PM metals are cycled to underlying soils. I combine long-term timeseries of FRNs and trace metals in bulk wet deposition, paired openfall and throughfall event-based deposition, and foliage collections, with annual litterfall and whole-tree mass balance, to describe processes and timescales that govern atmospheric metal dynamics in forest canopies. FRNs and metals accumulate efficiently and permanently in live and senesced vegetation, coupling them to the fate of organic matter. Foliar uptake occurs primarily through wet deposition (~80%), but efficiencies of wet (55%) and dry absorption (53%) by the canopy are similar. While the FRNs 7Be and 210Pb are fractionated at the single-leaf scale, with a deficit of 7Be possibly attributable to hyperacidity of dry-deposited PM, there is no discernible fractionation at the whole-canopy scale due to buffering capacity of the canopy and surfeit of organic surfaces for absorption. FRNs and metals accumulate in the canopy to the equivalent of many decades of deposition, primarily in non-foliar surfaces including lichen, moss, mold, and bark (collectively phyllosphere). These inventories are slowly recycled to underlying soils in association with dissolved organic carbon (DOC) and fine particulate organic matter (FPOM). Cumulatively the forest has a long memory with respect to atmospheric deposition, storing vast quantities of legacy pollutants for multi-decadal timescales, and thereby strongly influencing biogeochemical cycles of critical pollutants

Sunny and Share: Balancing Airspace Entitlement Rights Between Solar Energy Adopters and Their Neighbors

In an effort to ameliorate the effects of climate change, state and local governments have made increasingly large commitments to support solar energy adoption. For solar investments to be successful, however, solar adopters require unobstructed access to sunlight, which is directly at odds with the interests of neighbors and developers who value vertical development, especially in urban centers. To mitigate these looming conflicts, governments have enacted a variety of laws that assign airspace entitlements to either solar adopters or their neighbors. Unfortunately, these solutions are all poorly tailored for dense cities, which is where future airspace conflict is likely to concentrate. In response, this Note proposes a legal scheme designed to protect urban solar investments without ignoring neighbors\u27 property interests: the creation of solar development options ( SDOs ). Under this proposal, the solar adopter would be entitled to unilaterally create a solar easement across his neighbor\u27s airspace. But, in an important break from existing approaches, the owner of the neighboring property would receive a call option to retake her airspace entitlement along with an award of transferable development rights to compensate her for the encumbrance. The benefits of SDOs are numerous: they overcome the significant bargaining impediments plaguing urban stakeholders, properly compensate neighbors for valuable air rights without pricing out solar adopters, and preserve the autonomy of local governments to flexibly balance solar energy adoption and vertical development

Islamic Education in Syria: Undoing Secularism

Pendidikan Islam di Syiria adalah bagian dari strategi besar negara tersebut menuju nation-building. Sejalan dengan kebijakan pemerintah untuk mengeliminasi semua perbedaan di antara bangsa Syiria, pengajaran Islam di sekolah menanamkan ajaran Islam Sunni kepada semua muslim Syiria tanpa memandang suku. Namun, kurikulum agama ini berkebalikan dengan agenda pemerintah menuju sekularisme. Kurikulum agama Islam mengajarkan ketidaksetaraan di antara bangsa Syiria yang beragama Islam dan non-Islam. Ketidaksetaraan ini, yang menyebabkan perlakuan yang berbeda terhadap non-muslim, menjadikan mereka merasa tidak nyaman, dan pada akhirnya gelombang imigrasi ke negara lain pun terus terjadi

Silencing COQ8B in Aortic Smooth Muscle Cells Reveals Cellular Dysfunction Related to Changes in Cell Proliferation

Background/Objective: Thoracic aortic aneurysm (TAA) is a prevalent disorder that predisposes to aortic dissection. Prior work identified the ubiquinone biosynthesis gene COQ8B as a genetic modifier of TAA progression. We sought to determine the impact of decreased COQ8B on global transcription in aortic smooth muscle cells (SMCs). Methods: Primary human aortic SMCs from a healthy donor were seeded in 12-well plates. Six experimental conditions were created, each with 3 replicates: 1) siRNA targeting COQ8B (siCOQ8B); 2) siRNA targeting the dominant TAA gene SMAD3 (siSMAD3); 3) negative controlsiRNA (siNeg); 4) siCOQ8B and siSMAD3; 5) siCOQ8B with Angiotensin II (AngII) stimulation (siCOQ8B+AngII); 6) siNeg+AngII. RNA was extracted approximately 48 hours post-siRNA transfection and, for AngII conditions, after 1 hour of incubation with AngII (100 nM).  mRNAsequencing was performed and downstream analysis utilized R packages EdgeR and topGO. Results: Multidimensional scaling identified distinct clustering of samples by experimental condition. Downregulated genes in siCOQ8B were enriched for Gene Ontology pathways related to cell proliferation including cell cycle regulators, DNA replication, and mitosis. MYOCD, a master regulator of SMC homeostasis, was downregulated. Similar proliferation-related pathways were enriched in siCOQ8B+siSMAD3 and siCOQ8B+AngII compared to siNeg. Pathways related to cell proliferation in siCOQ8B+AngII cells were downregulated when compared to siCOQ8B which indicates that AngII infusion in the context of COQ8B silencing may further dysregulate cell proliferation pathways. Conclusion: The results indicate that COQ8B has an important role in cell cycle processes in aortic SMCs, including when SMCs are exposed to stressors associated with TAA development. Stimulation of angiotensin receptors may exacerbate the effects of decreased COQ8B in these processes. To investigate these experimental results in human pathology, bulk RNA samples and intact nuclei have been isolated from frozen human aortic specimens and prepared for transcriptomic analysis

Silencing COQ8B in Aortic Smooth Muscle Cells Reveals Cellular Dysfunction Related to Changes in Cell Proliferation

Background/Objective: Thoracic aortic aneu­rysm (TAA) is a prevalent disorder that predis­poses to aortic dissection. Prior work identified the ubiquinone biosynthesis gene COQ8B as a genetic modifier of TAA progression. We sought to determine the impact of decreased COQ8B on global transcription in aortic smooth muscle cells (SMCs). Methods: Primary human aortic SMCs from a healthy donor were seeded in 12-well plates. Six experimental conditions were created, each with 3 replicates: 1) siRNA targeting COQ8B (siCO­Q8B); 2) siRNA targeting the dominant TAA gene SMAD3 (siSMAD3); 3) negative control siRNA (siNeg); 4) siCOQ8B and siSMAD3; 5) siCOQ8B with Angiotensin II (AngII) stimula­tion (siCOQ8B+AngII); 6) siNeg+AngII. RNA was extracted approximately 48 hours post-siR­NA transfection and, for AngII conditions, after 1 hour of incubation with AngII (100 nM). mRNA-sequencing was performed and down­stream analysis utilized R packages EdgeR and topGO. Results: Multidimensional scaling identified dis­tinct clustering of samples by experimental con­dition. Downregulated genes in siCOQ8B were enriched for Gene Ontology pathways related to cell proliferation including cell cycle regulators, DNA replication, and mitosis. MYOCD, a mas­ter regulator of SMC homeostasis, was down­regulated. Similar proliferation-related pathways were enriched in siCOQ8B+siSMAD3 and siCOQ8B+AngII compared to siNeg. Pathways related to cell proliferation in siCOQ8B+AngII cells were downregulated when compared to siCOQ8B which indicates that AngII infusion in the context of COQ8B silencing may further dysregulate cell proliferation pathways. Conclusion/Implications: The results indi­cate that COQ8B has an important role in cell cycle processes in aortic SMCs, including when SMCs are exposed to stressors associated with TAA development. Stimulation of angiotensin receptors may exacerbate the effects of decreased COQ8B in these processes. To investigate these experimental results in human pathology, bulk RNA samples and intact nuclei have been iso­lated from frozen human aortic specimens and prepared for transcriptomic analysis

Origin and Provenance of Spherules and Magnetic Grains at the Younger Dryas Boundary

One or more bolide impacts are hypothesized to have triggered the Younger Dryas cooling at ∼12.9 ka. In support of this hypothesis, varying peak abundances of magnetic grains with iridium and magnetic microspherules have been reported at the Younger Dryas boundary (YDB). We show that bulk sediment and/or magnetic grains/microspherules collected from the YDB sites in Arizona, Michigan, New Mexico, New Jersey, and Ohio have (187)Os/(188)Os ratios ≥1.0, similar to average upper continental crust (= 1.3), indicating a terrestrial origin of osmium (Os) in these samples. In contrast, bulk sediments from YDB sites in Belgium and Pennsylvania exhibit (187)Os/(188)Os ratios \u3c\u3c1.0 and at face value suggest mixing with extraterrestrial Os with (187)Os/(188)Os of ∼0.13. However, the Os concentration in bulk sample and magnetic grains from Belgium is 2.8 pg/g and 15 pg/g, respectively, much lower than that in average upper continental crust (=31 pg/g), indicating no meteoritic contribution. The YDB site in Pennsylvania is remarkable in yielding 2- to 5-mm diameter spherules containing minerals such as suessite (Fe-Ni silicide) that form at temperatures in excess of 2000 °C. Gross texture, mineralogy, and age of the spherules appear consistent with their formation as ejecta from an impact 12.9 ka ago. The (187)Os/(188)Os ratios of the spherules and their leachates are often low, but Os in these objects is likely terrestrially derived. The rare earth element patterns and Sr and Nd isotopes of the spherules indicate that their source lies in 1.5-Ga Quebecia terrain in the Grenville Province of northeastern North America

Surficial Redistribution of Fallout 131iodine in a Small Temperate Catchment

Isotopes of iodine play significant environmental roles, including a limiting micronutrient (127I), an acute radiotoxin (131I), and a geochemical tracer (129I). But the cycling of iodine through terrestrial ecosystems is poorly understood, due to its complex environmental chemistry and low natural abundance. To better understand iodine transport and fate in a terrestrial ecosystem, we traced fallout 131iodine throughout a small temperate catchment following contamination by the 11 March 2011 failure of the Fukushima Daiichi nuclear power facility. We find that radioiodine fallout is actively and efficiently scavenged by the soil system, where it is continuously focused to surface soils over a period of weeks following deposition. Mobilization of historic (pre-Fukushima) 137cesium observed concurrently in these soils suggests that the focusing of iodine to surface soils may be biologically mediated. Atmospherically deposited iodine is subsequently redistributed from the soil system via fluvial processes in a manner analogous to that of the particle-reactive tracer 7beryllium, a consequence of the radionuclides’ shared sorption affinity for fine, particulate organic matter. These processes of surficial redistribution create iodine hotspots in the terrestrial environment where fine, particulate organic matter accumulates, and in this manner regulate the delivery of iodine nutrients and toxins alike from small catchments to larger river systems, lakes and estuaries

Contrasting sensitivity of lake sediment n-alkanoic acids and n-alkanes to basin-scale vegetation and regional-scale precipitation δ2H in the Adirondack Mountains, NY (USA)

The hydrogen isotope values of plant waxes (δ2Hwax) primarily reflect plant source water. δ2Hwax preserved in lake sediments has therefore been widely used to investigate past hydroclimate. The processes by which plant waxes are integrated at regional and catchment scales are poorly understood and may affect the δ2Hwax values recorded in sediments. Here, we assess the variability of sedimentary δ2Hwax for two plant wax compound classes (n-alkanes and n-alkanoic acids) across 12 lakes in the Adirondack Mountains that receive similar regional precipitation δ2H but vary at the catchment-scale in terms of vegetation structure and basin morphology. Total long-chain (n-C27 to n-C35) alkane concentrations were similar across all sites (191 ± 53 µg/g TOC) while total long-chain (n-C28 and n-C30) alkanoic acid concentrations were more variable (117 ± 116 µg/g TOC) and may reflect shoreline vegetation composition. Lakes with shorelines dominated by evergreen gymnosperm plants had significantly higher concentrations of long-chain n-alkanoic acids relative to n-alkanes, consistent with our observations that deciduous angiosperms produced more long-chain n-alkanes than evergreen gymnosperms (471 and 33 µg/g TOC, respectively). In sediments, the most abundant chain lengths in each compound class were n-C29 alkane and n-C28 alkanoic acid, which had mean δ2H values of −188 ± 6‰ and −164 ± 9‰, respectively. Across sites, the range in sedimentary n-C29 alkane (22‰) and n-C28 alkanoic acid δ2H (35‰) was larger than expected based on the total range in modeled mean annual precipitation δ2H (4‰). We observed larger mean εapp (based on absolute values) for n-alkanes (−123‰) than for n-alkanoic acids (−97‰). Across sites, the δ2H offset between n-C29 alkane and the biosynthetic precursor n-C30 alkanoic acid (εC29-C30) ranged from −8 to −58‰, which was more variable than expected based on observations in temperate trees (−20 to −30‰). Sediments with greater aquatic organic matter contributions (lower C/N ratios) had significantly larger (absolute) εC29-C30 values, which may reflect long-chain n-alkanoic acids from aquatic sources. Concentration and δ2Hwax data in Adirondack lakes suggest that long-chain n-alkanes are more sensitive to regional-scale precipitation signals, while n-alkanoic acids are more sensitive to basin-scale differences in catchment vegetation and wax sourcing

Evaluation of Tissue-engineered Tendon Enthesis Polymer Constructs

Both scientists and clinicians have proposed tissue engineering as the future of medicine. The possibilities for tissue engineering, that is, fabrication of tissues and organs in the laboratory and their translation to patients, appear to be endless, and many believe that this new approach in medicine will result in abolishing many common ailments, injuries, and congenital defects. Injuries to a tendon enthesis, the normal tissue connection between tendon and bone, are of particular concern to clinicians because of their frequency and failure to repair as a result of surgery. While these injuries may not be life threatening, they can certainly limit mobility and reduce the quality of life in those affected individuals. Fabrication of a tendon enthesis by tissue engineering would offer an alternative to the routine of surgery now performed and present potential for treatment and healing of the tissue now unavailable. In the current prospective study, polymer scaffolds created using polycaprolactone (PCL), poly-L lactide (PLLA), or nano-polyglycolic acid (nPGA) were seeded with chondrocytes, tenocytes, and periosteum for the development of cartilage, tendon and bone, respectively, and then implanted into six athymic nude mice for a period of 10 weeks. One group of constructs (scaffolds and cells or tissue together) was tethered to the mice 2 in order to determine if mechanical forces improved or were required for tendon enthesis formation compared to a group of identical implanted constructs that were not tethered. Analysis by histology illustrated a noticeable increase in tissue formation around the area of anticipated enthesis in tethered constructs when compared to constructs that were not tethered. Based on these data, it is believed that mechanical tension (tethering) is required for the formation of a tendon enthesi

Better Pumps: Reliable Handpump Infrastructure

Approximately 90 million people in Africa lack access to safe drinking water, despite having water infrastructure installed in their community. The India Mark II and the Afridev handpumps are among the most widely used handpumps in the world. Sadly, studies show that approximately 30% of these handpumps are non-operational due to failures of the bearings, seals, head flange, and other common components. The Better Pumps team of the Collaboratory provides engineering support for partners who are working to improve handpump sustainability. We partnered with Tony Beers and AlignedWorks to validate a bearing test methodology for the India Mark II handpump. By modifying the loading conditions in our handpump test machine, we were able to replicate failures observed by AlignedWorks in a field trial of their bearing design. We partnered with Matt Schwiebert and Living Water International to test new seal designs for the India Mark II and Afridev handpumps and to measure head flange deflections in the India Mark II handpump. Seal performance data collected by the team was used to validate a new design in advance of field trials by Living Water International. Head flange deflection data was collected for partner benchmarking of their computational analysis. Test methodologies and results are reported.https://mosaic.messiah.edu/engr2021/1000/thumbnail.jp