343 research outputs found
Flow Chamber for Confocal Tracking of Particles in Bone
Interstitial fluid flow in the lacunar-canalicular system (LCS) of bone is recognized as a potential regulator of bone remodeling. Movement of fluid across bone cells called osteocytes regulates gene expression that leads to either bone formation or resorption. Interstitial fluid moves in response to bone loading during daily activity, and bone growth occurs to compensate for these loads, affecting bone shape and strength. While interstitial fluid flow is thoroughly studied using computational models, there is a critical need to study flow in real bone samples with imaging techniques. Flow velocities determined from imaging will be more accurate than computational models due to the simplifying assumptions that are made when building a model. This study presents a sealed system that allows for imaging of particle flow in bone using confocal microscopy. The flow apparatus was designed in Autodesk Fusion 360 and fluid flow was controlled using an electric constant flow pump. For comparison with experimental data, a computational model based on confocal microscopy images was created to calculate flow velocities in the LCS using ANSYS Fluent. The results of this study will develop a novel method for tracking interstitial fluid flow in the LCS, providing a new strategy to study how fluid flow affects bone remodeling. The ability to measure fluid flow in bone allows for the connection of age or disease related alterations in the LCS to changes in bone mass and structure
Identifying the Pathways and Experiences of Asian Students\u27 Engineering Major Choice
Asian students’ pathways and experiences in engineering are not well-studied. Understanding pathways and experiences can inform students, parents, educators, and policymakers how to better approach the engineering major choice process. This study identifies pathways and experiences of Asian students choosing to major in engineering. Eleven semi-structured interviews of Asian students at a major research institution were analyzed in NVivo using thematic analysis. In this study, 8 Asian students chose engineering as a field of study and subsequently chose an engineering major while 3 chose an engineering major directly. Students following either pathway shared catalyzing interests, such as math and science, and the influence of parents but diverged in the decision-making processes. Students who chose their major after choosing engineering considered a broad range of interests in their decision-making and were likely to mention additional figures of influence such as peers, graduate assistants, teachers, and professors. These students actively engaged in exploration and weighing of interests by comparing likes and dislikes. Overall, most students acknowledged parental influence. International students tended to discuss parental influence within the context of financial support/burden. These findings are relevant for the investigation of student persistence, recruitment, and retention and the design of multiple-institution studies. Researchers can develop questions based on the findings to determine what aspects of student pathways and experiences can be affected through policy and other actionable changes
A Case Study of Engineering Students’ Experiences with the Co-Op Application Process
Engineering faculty and advisors emphasize the importance of obtaining industry experience in addition to academic learning. One way universities encourage their students to obtain hands-on work experiences is through cooperative education (co-op) programs. Previous studies have examined the advantages and disadvantages of co-op participation, but the application process for students has not been closely examined. Studying this process will show how academic institutions and companies can potentially enhance the student experience of applying for a co-op position. This study examines student experiences with the co-op application process based on interviews with engineering students at a research-intensive university in the Midwestern U.S. Results indicate that barriers to co-op participation include conflicting offer deadlines established by companies and unclear processes for students in employer matching. Research findings regarding the co-op application and placement process can potentially inform universities and companies on how students use resources designed to help students during the co-op application process, as well as the challenges some students encounter
The impact of ESG on financial performance:A revisit with a regression discontinuity approach
EST contig-based SSR linkage maps for Malus × domestica cv Royal Gala and an apple scab resistant accession of M. sieversii , the progenitor species of domestic apple
Malus sieversii is a progenitor species of domestic apple M.×domestica. Using population "GMAL 4595” of 188 individuals derived from a cross of Royal Gala×PI 613988 (apple scab resistant, M. sieversii), 287 SSR (simple sequence repeats) loci were mapped. Of these SSRs, 80 are published anchors and 207 are newly developed EST (expressed sequence tag) contig-based SSRs, representing 1,630 Malus EST accessions in GenBank. Putative gene functions of these EST contigs are diverse, including regulating plant growth, development and response to environmental stresses. Among the 80 published SSRs, 18 are PI 613988 specific, 38 are common and 24 are Royal Gala specific. Out of the 207 newly developed EST contig-based SSRs, 79 are PI 613988 specific, 45 are common and 83 are Royal Gala specific. These results led to the construction of a M. sieversii map (1,387.0cM) of 180 SSR markers and a Royal Gala map (1,283.4cM) of 190 SSR markers. Mapping of scab resistance was independently conducted in two subsets of population "GMAL 4595” that were inoculated with Ventura inaequalis races (1) and (2), respectively. In combination with the two major resistance reactions Chl (chlorotic lesions) and SN (stellate necrosis) to each race, four subsets of resistance data, i.e., Chl/race (1), SN/race (1), Chl/race (2) and SN/race (2), were constituted and analyzed, leading to four resistance loci mapped to the linkage group 2 of PI 613988; SNR1 (stellate necrosis resistance to race (1)) and SNR2 are tightly linked in a region of known scab resistance genes, and ChlR1 (Chlorotic lesion resistance to race (1)) and ChlR2 are also linked tightly but in a region without known scab resistance genes. The utility of the two linkage maps, the new EST contig-based markers and M. sieversii as sources of apple scab resistance are discusse
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New Tropical Peatland Gas and Particulate Emissions Factors Indicate 2015 Indonesian Fires Released Far More Particulate Matter (but Less Methane) than Current Inventories Imply
Deforestation and draining of the peatlands in equatorial SE Asia has greatly increased their flammability, and in September-October 2015 a strong El Niño-related drought led to further drying and to widespread burning across parts of Indonesia, primarily on Kalimantan and Sumatra. These fires resulted in some of the worst sustained outdoor air pollution ever recorded, with atmospheric particulate matter (PM) concentrations exceeding those considered "extremely hazardous to health" by up to an order of magnitude. Here we report unique in situ air quality data and tropical peatland fire emissions factors (EFs) for key carbonaceous trace gases (CO2, CH4 and CO) and PM2.5 and black carbon (BC) particulates, based on measurements conducted on Kalimantan at the height of the 2015 fires, both at locations of "pure" sub-surface peat burning and spreading vegetation fires atop burning peat. PM2.5 are the most significant smoke constituent in terms of human health impacts, and we find in situ PM2.5 emissions factors for pure peat burning to be 17.8 to 22.3 g·kg-1, and for spreading vegetation fires atop burning peat 44 to 61 g·kg-1, both far higher than past laboratory burning of tropical peat has suggested. The latter are some of the highest PM2.5 emissions factors measured worldwide. Using our peatland CO2, CH4 and CO emissions factors (1779 ± 55 g·kg-1, 238 ± 36 g·kg-1, and 7.8 ± 2.3 g·kg-1 respectively) alongside in situ measured peat carbon content (610 ± 47 g-C·kg-1) we provide a new 358 Tg (± 30%) fuel consumption estimate for the 2015 Indonesian fires, which is less than that provided by the GFEDv4.1s and GFASv1.2 global fire emissions inventories by 23% and 34% respectively, and which due to our lower EFCH4 produces far less (~3×) methane. However, our mean in situ derived EFPM2.5 for these extreme tropical peatland fires (28 ± 6 g·kg-1) is far higher than current emissions inventories assume, resulting in our total PM2.5 emissions estimate (9.1 ± 3.5 Tg) being many times higher than GFEDv4.1s, GFASv1.2 and FINNv2, despite our lower fuel consumption. We find that two thirds of the emitted PM2.5 come from Kalimantan, one third from Sumatra, and 95% from burning peatlands. Using new geostationary fire radiative power (FRP) data we map the fire emissions' spatio-temporal variations in far greater detail than ever before (hourly, 0.05°), identifying a tropical peatland fire diurnal cycle twice as wide as in neighboring non-peat areas and peaking much later in the day. Our data show that a combination of greatly elevated PM2.5 emissions factors, large areas of simultaneous, long-duration burning, and very high peat fuel consumption per unit area made these Sept to Oct tropical peatland fires the greatest wildfire source of particulate matter globally in 2015, furthering evidence for a regional atmospheric pollution impact whose particulate matter component in particular led to millions of citizens being exposed to extremely poor levels of air quality for substantial periods. © 2018 by the authors
Adnectins: engineered target-binding protein therapeutics
AdnectinsTM are a new family of therapeutic proteins based on the 10th fibronectin type III domain, and designed to bind with high affinity and specificity to therapeutically relevant targets. Adnectins share with antibody variable domains a beta-sheet sandwich fold with diversified loops, but differ from antibodies in primary sequence and have a simpler, single-domain structure without disulfide bonds. As a consequence, Adnectins bind targets with affinity and specificity as high as those of antibodies, but are easier to manipulate genetically and compatible with bacterial expression systems. Adnectins that bind macromolecular targets with nanomolar and picomolar affinity have been selected using in vitro evolution methods, including mRNA display, phage display and yeast display. CT-322, a PEGylated, anti-angiogenic Adnectin that binds vascular endothelial growth factor (VEGF) receptor 2 and blocks its interaction with VEGF A, C and D, is being evaluated in Phase II clinical trials for efficacy in several oncology indications
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