Stormwater drains are important sinks for microplastics and potentially aid the transport of microplastics from terrestrial to marine environments. Samples were collected from sediments in five ...stormwater drainage systems with different land uses, area, population, and sediment characteristics. Microplastic concentrations within the drainage network varied between 0 and 3500 microplastics per kg of dry sediment, with a mean concentration of 664 particles per kg. The majority of microplastics found were fibres. Polyethylene and polypropylene were the dominant polymer types (μ-FTIR). Based on a Generalized Linear Mixed Model, the expected number of microplastics for a representative urban drain was 760 particles per kg, with 245 particles per kg expected for an agricultural drain. Sediment grain size was a predictor for microplastic abundance, with sandier sediments containing more microplastics. This study is the first to quantify microplastic pollution in stormwater drainage systems in Western Australia.
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•Microplastic concentration is lower in catchments with less intensive urbanization.•Microplastic concentration is higher in sediments with a greater proportion of sand.•Polyethylene and polypropylene are the most common polymers in stormwater drains.
•Microplastic concentration is lower in catchments with less intensive urbanization.•Microplastic concentration is higher in sediments with a greater proportion of sand.•Polyethylene and ...polypropylene are the most common polymers in stormwater drains.
As countries move towards or achieve measles elimination status, serosurveillance is an important public health tool. However, a major challenge of serosurveillance is finding a feasible, accurate, ...cost-effective, and high throughput assay to measure measles antibody concentrations and estimate susceptibility in a population. We conducted a systematic review to assess, characterize, and - to the extent possible - quantify the performance of measles IgG enzyme-linked assays (EIAs) compared to the gold standard, plaque reduction neutralization tests (PRNT).
We followed the PRISMA statement for a systematic literature search and methods for conducting and reporting systematic reviews and meta-analyses recommended by the Cochrane Screening and Diagnostic Tests Methods Group. We identified studies through PubMed and Embase electronic databases and included serologic studies detecting measles virus IgG antibodies among participants of any age from the same source population that reported an index (any EIA or multiple bead-based assays, MBA) and reference test (PRNT) using sera, whole blood, or plasma. Measures of diagnostic accuracy with 95% confidence intervals (CI) were abstracted for each study result, where reported.
We identified 550 unique publications and identified 36 eligible studies for analysis. We classified studies as high, medium, or low quality; results from high quality studies are reported. Because most high quality studies used the Siemens Enzygnost EIA kit, we generate individual and pooled diagnostic accuracy estimates for this assay separately. Median sensitivity of the Enzygnost EIA was 92.1% IQR = 82.3, 95.7; median specificity was 96.9 93.0, 100.0. Pooled sensitivity and specificity from studies using the Enzygnost kit were 91.6 (95%CI: 80.7,96.6) and 96.0 (95%CI: 90.9,98.3), respectively. The sensitivity of all other EIA kits across high quality studies ranged from 0% to 98.9% with median (IQR) = 90.6 86.6, 95.2; specificity ranged from 58.8% to 100.0% with median (IQR) = 100.0 88.7, 100.0.
Evidence on the diagnostic accuracy of currently available measles IgG EIAs is variable, insufficient, and may not be fit for purpose for serosurveillance goals. Additional studies evaluating the diagnostic accuracy of measles EIAs, including MBAs, should be conducted among diverse populations and settings (e.g., vaccination status, elimination/endemic status, age groups).
Prior to direct-acting antivirals (DAAs), HCV incidence rose among men who have sex with men (MSM) living with HIV infection in Germany despite high hepatitis C virus (HCV) treatment rates. We ...establish a HCV elimination modeling framework to evaluate whether existing treatment rates can achieve the World Health Organization (WHO) incidence target among MSM living with HIV in Germany.
To evaluate progress towards HCV elimination in Germany, we adapted a previously published HCV transmission model among MSM living with diagnosed HIV. We modelled HCV incidence and prevalence until 2030 (relative to 2015) under existing treatment and DAA scale-up and explored potential impacts of disruptions in treatment and behavioral risk reduction due to the COVID-19 pandemic.
Continuing current treatment rates will result in stable HCV incidence among MSM living with HIV in Germany between 2015-2030. The WHO HCV incidence target is achievable under DAA scale-up to 100% treatment combined with treatment of those previously diagnosed and untreated (at a rate of 15%/year) and would result in greater reductions with early treatment (3 vs 6 months) reducing incidence from 4.0/100person-years to 0.8/100person-years by 2030. A 12-month disruption to HCV treatment (20% reduction) and risk behaviors (25%,50%,75% reduction) during the COVID-19 pandemic would result in a 15% relative increase in total HCV incidence in 2030 compared to that expected under the status quo.
HCV elimination among MSM living with HIV in Germany requires further DAA scale-up among those newly diagnosed combined with efforts to treat those previously diagnosed but untreated. Prospective monitoring will establish whether Germany is on track for HCV microelimination.
Background
Conceptual understanding is critical to both engineering education and practice. In fact, many undergraduate courses focus on developing students' knowledge and understanding of core ...engineering concepts. At the same time, a growing body of literature points to substantial gaps across educational and professional practice contexts, including how problems are embodied and solved.
Purpose
The purpose of this study was to explore potential differences in conceptual understanding across engineering students and professional engineers. To do so, we compared the responses of civil engineering practitioners to the Statics Concept Inventory (SCI) to those of engineering students enrolled in statics courses.
Design/Method
We administered the SCI to 95 practicing civil engineers and compared their responses to an existing dataset from 1,372 engineering students. We conducted three comparisons: overall SCI score, concept subscores, and item‐by‐item.
Results
Students generally outperformed engineers on the SCI in terms of overall performance. However, on closer inspection, students' superior performance appears to be driven by differences in knowledge or understanding of specific statics concepts rather than a stronger understanding in general.
Conclusions
We caution against interpretations that imply students have a better understanding of statics concepts. Instead, our results suggest that differences in the way concepts are situated and applied across school and workplace contexts might account for the differences in the performance observed. These findings raise critical questions regarding the nature of concepts and the immutability of common academic representations, and point to the need for further qualitative and exploratory work investigating concepts in practice.
In this study, we report the beneficial effects of a newly identified dermal cell subpopulation expressing the ATP‐binding cassette subfamily B member 5 (ABCB5) for the therapy of nonhealing wounds. ...Local administration of dermal ABCB5+‐derived mesenchymal stem cells (MSCs) attenuated macrophage‐dominated inflammation and thereby accelerated healing of full‐thickness excisional wounds in the iron‐overload mouse model mimicking the nonhealing state of human venous leg ulcers. The observed beneficial effects were due to interleukin‐1 receptor antagonist (IL‐1RA) secreted by ABCB5+‐derived MSCs, which dampened inflammation and shifted the prevalence of unrestrained proinflammatory M1 macrophages toward repair promoting anti‐inflammatory M2 macrophages at the wound site. The beneficial anti‐inflammatory effect of IL‐1RA released from ABCB5+‐derived MSCs on human wound macrophages was conserved in humanized NOD‐scid IL2rγ
null mice. In conclusion, human dermal ABCB5+ cells represent a novel, easily accessible, and marker‐enriched source of MSCs, which holds substantial promise to successfully treat chronic nonhealing wounds in humans. Stem Cells 2019;37:1057–1074
In chronic wounds, M1 macrophages and their autocrine amplification of inflammasome‐generated interleukin‐1 (IL‐1) beta perpetuates a proinflammatory environment impeding the progression through normal phases of wound healing. IL‐1 receptor antagonist adaptively secreted by ATP‐binding cassette subfamily B member 5+ mesenchymal stem cells when exposed to the M1 macrophage imprinted proinflammatory wound environment, attenuates this vicious cycle, and leads to a shift from proinflammatory M1 toward anti‐inflammatory, wound healing‐promoting M2 macrophages as observed in normal wound healing.
Abstract
Fusion crusts form during the atmospheric entry heating of meteorites and preserve a record of the conditions that occurred during deceleration in the atmosphere. The fusion crust of the ...Winchcombe meteorite closely resembles that of other stony meteorites, and in particular CM2 chondrites, since it is dominated by olivine phenocrysts set in a glassy mesostasis with magnetite, and is highly vesicular. Dehydration cracks are unusually abundant in Winchcombe. Failure of this weak layer is an additional ablation mechanism to produce large numbers of particles during deceleration, consistent with the observation of pulses of plasma in videos of the Winchcombe fireball. Calving events might provide an observable phenomenon related to meteorites that are particularly susceptible to dehydration. Oscillatory zoning is observed within olivine phenocrysts in the fusion crust, in contrast to other meteorites, perhaps owing to temperature fluctuations resulting from calving events. Magnetite monolayers are found in the crust, and have also not been previously reported, and form discontinuous strata. These features grade into magnetite rims formed on the external surface of the crust and suggest the trapping of surface magnetite by collapse of melt. Magnetite monolayers may be a feature of meteorites that undergo significant degassing. Silicate warts with dendritic textures were observed and are suggested to be droplets ablated from another stone in the shower. They, therefore, represent the first evidence for intershower transfer of ablation materials and are consistent with the other evidence in the Winchcombe meteorite for unusually intense gas loss and ablation, despite its low entry velocity.
Background While rapid healing of diabetic foot ulcers (DFUs) is highly desirable to avoid infections, amputations and life-threatening complications, DFUs often respond poorly to standard treatment. ...GMP-manufactured skin-derived ABCB5.sup.+ mesenchymal stem cells (MSCs) might provide a new adjunctive DFU treatment, based on their remarkable skin wound homing and engraftment potential, their ability to adaptively respond to inflammatory signals, and their wound healing-promoting efficacy in mouse wound models and human chronic venous ulcers. Methods The angiogenic potential of ABCB5.sup.+ MSCs was characterized with respect to angiogenic factor expression at the mRNA and protein level, in vitro endothelial trans-differentiation and tube formation potential, and perfusion-restoring capacity in a mouse hindlimb ischemia model. Finally, the efficacy and safety of ABCB5.sup.+ MSCs for topical adjunctive treatment of chronic, standard therapy-refractory, neuropathic plantar DFUs were assessed in an open-label single-arm clinical trial. Results Hypoxic incubation of ABCB5.sup.+ MSCs led to posttranslational stabilization of the hypoxia-inducible transcription factor 1alpha (HIF-1alpha) and upregulation of HIF-1alpha mRNA levels. HIF-1alpha pathway activation was accompanied by upregulation of vascular endothelial growth factor (VEGF) transcription and increase in VEGF protein secretion. Upon culture in growth factor-supplemented medium, ABCB5.sup.+ MSCs expressed the endothelial-lineage marker CD31, and after seeding on gel matrix, ABCB5.sup.+ MSCs demonstrated formation of capillary-like structures comparable with human umbilical vein endothelial cells. Intramuscularly injected ABCB5.sup.+ MSCs to mice with surgically induced hindlimb ischemia accelerated perfusion recovery as measured by laser Doppler blood perfusion imaging and enhanced capillary proliferation and vascularization in the ischemic muscles. Adjunctive topical application of ABCB5.sup.+ MSCs onto therapy-refractory DFUs elicited median wound surface area reductions from baseline of 59% (full analysis set, n = 23), 64% (per-protocol set, n = 20) and 67% (subgroup of responders, n = 17) at week 12, while no treatment-related adverse events were observed. Conclusions The present observations identify GMP-manufactured ABCB5.sup.+ dermal MSCs as a potential, safe candidate for adjunctive therapy of otherwise incurable DFUs and justify the conduct of a larger, randomized controlled trial to validate the clinical efficacy. Trial registration: ClinicalTrials.gov, NCT03267784, Registered 30 August 2017, Keywords: ABCB5, Advanced-therapy medicinal product, Angiogenesis, Chronic wound, Diabetic foot ulcer, Mesenchymal stem cells, Wound healing
Abstract
Background
Despite high hepatitis C virus (HCV) treatment rates, HCV incidence among human immunodeficiency virus (HIV)–infected men who have sex with men (HIV-infected MSM) in Germany rose ...before HCV direct-acting antivirals (DAAs). We model what intervention can achieve the World Health Organization (WHO) elimination target of an 80% reduction in HCV incidence by 2030 among HIV-infected MSM in Berlin.
Methods
An HCV transmission model among HIV-diagnosed MSM was calibrated to Berlin (rising HCV incidence and high rates of HCV testing and treatment). We modeled the HCV incidence among HIV-diagnosed MSM in Berlin until 2030 (relative to 2015 WHO baseline) under scenarios of DAA scale-up with or without behavior change (among HIV-diagnosed MSM and/or all MSM).
Results
Continuing current treatment rates will marginally reduce the HCV incidence among HIV-diagnosed MSM in Berlin by 2030. Scaling up DAA treatment rates, beginning in 2018, to 100% of newly diagnosed HCV infections within 3 months of diagnosis and 25% each year of previously diagnosed and untreated HCV infections could reduce the HCV incidence by 61% (95% confidence interval, 55.4%–66.7%) by 2030. The WHO target would likely be achieved by combining DAA scale-up with a 40% reduction in HCV transmission among HIV-diagnosed MSM and a 20% reduction among HIV-undiagnosed or HIV-uninfected MSM.
Discussion
HCV elimination among HIV-infected MSM in Berlin likely requires combining DAA scale-up with moderately effective behavioral interventions to reduce risk among all MSM.
Dynamic modeling indicates that hepatitis C virus elimination among human immunodeficiency virus–infected men who have sex with men (MSM) in Berlin likely requires combining direct-acting antiviral scale-up with moderately effective behavioral interventions to reduce risk among all MSM.
Background
Conceptual change is a process in which an individual's understanding and the basis of this understanding change over time. Vosniadou's framework theory explains conceptual change in terms ...of how students learn to relate the observable and unobservable in everyday phenomena. As a result, courses that relate physical phenomena to complex ions – such as Mechanics of Materials – are useful spaces for exploring conceptual change.
Purpose
This paper leverages Vosniadou's framework theory of conceptual change to explore students' reasoning and to identify trends about their understanding of fundamental concepts of mechanics of materials.
Design/Method
This research is based on the qualitative analysis of semi‐structured interviews with ninety engineering undergraduate students enrolled in a Mechanics of Materials course. Interviews were qualitatively analyzed to capture students' understanding of mechanics of materials concepts under different loading scenarios.
Results
Our results found two common persistent beliefs in student reasoning in both the axial and bending load cases: that shear and normal stress depend on (a) the direction and (b) the location of an applied load. We propose that students' “nonscientific” beliefs are part of an intermediate, synthetic model of conceptual understanding created as students assimilate their presuppositions of mechanics of materials with newly acquired information based on the scientific concepts.
Conclusions
Students form naïve conceptual beliefs based on their experiences with loading scenarios that impede their abilities to more effectively assimilate new concepts into their current framework theories. A better understanding of student reasoning and what influences it can inform instructional techniques to help students develop science‐based reasoning in mechanics of materials.
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