Transport of Sub-micron Aerosols in Bifurcations

The convective-diffusive transport of sub-micron aerosols in an oscillatory laminar flow within a 2-D single bifurcation is studied, using order-of-magnitude analysis and numerical simulation using a commercial software (FEMLAB®). Based on the similarity between momentum and mass transfer equations, various transient mass transport regimes are classified and scaled according to Strouhal and beta numbers. Results show that the mass transfer rate is highest at the carinal ridge and there is a phase-shift in diffusive transport time if the beta number is greater than one. It is also shown that diffusive mass transfer becomes independent of the oscillating outer flow if the Strouhal number is greater than one.Singapore-MIT Alliance (SMA

Secondary Flow and Upstream Dynamics in Double Bifurcation Model

Flow behavior in bifurcation models is of great importance to health risk assessments and pulmonary drug delivery. This is particularly true of secondary flow behavior in multi-bifurcation models. Previously, both numerical and experimental methods have shown that four-vortex secondary flow structures can develop in the cross-sections of grand-daughter branches. This work shows that the development of secondary flow in the grand-daughter tubes is due to local stretching of vortex lines in the upstream DT. Scaling arguments have been used to derive two critical parameters governing this particular vorticity transport problem. A simple model for vorticity generation and transport is proposed, taking into account the geometric limitations imposed by the rigid walls of the tubes.Singapore-MIT Alliance (SMA

T-cell–specific PTPN2 deficiency in NOD mice accelerates the development of type 1 diabetes and autoimmune comorbidities

Genome-wide association studies have identified PTPN2 as an important non-major histocompatibility complex gene for autoimmunity. Single nucleotide polymorphisms that reduce PTPN2 expression have been linked with the development of varied autoimmune disorders, including type 1 diabetes. The tyrosine-phosphatase PTPN2 attenuates T cell receptor and cytokine signalling in T cells to maintain peripheral tolerance, but the extent to which PTPN2-deficiency in T cells might influence type 1 diabetes onset remains unclear. Non-Obese Diabetic (NOD) mice develop spontaneous autoimmune type 1 diabetes, similar to that seen in humans. T cell PTPN2-deficiency in NOD mice markedly accelerated the onset and increased the incidence of type 1 diabetes, as well as that of other disorders, including colitis and Sjogren’s syndrome. Although PTPN2-deficiency in CD8+ T cells alone was able to drive the destruction of pancreatic β cells and onset of diabetes, T cell-specific PTPN2-deficiency was also accompanied by increased CD4+ T-helper type 1 differentiation and T follicular helper cell polarisation and an increased abundance of B cells in pancreatic islets as seen in human type 1 diabetes. These findings causally link PTPN2-deficiency in T cells with the development of type 1 diabetes and associated autoimmune co-morbidities

Environment and shipping drive environmental DNA beta-diversity among commercial ports

The spread of nonindigenous species by shipping is a large and growing global problem that harms coastal ecosystems and economies and may blur coastal biogeographical patterns. This study coupled eukaryotic environmental DNA (eDNA) metabarcoding with dissimilarity regression to test the hypothesis that ship-borne species spread homogenizes port communities. We first collected and metabarcoded water samples from ports in Europe, Asia, Australia and the Americas. We then calculated community dissimilarities between port pairs and tested for effects of environmental dissimilarity, biogeographical region and four alternative measures of ship-borne species transport risk. We predicted that higher shipping between ports would decrease community dissimilarity, that the effect of shipping would be small compared to that of environment dissimilarity and shared biogeography, and that more complex shipping risk metrics (which account for ballast water and stepping-stone spread) would perform better. Consistent with our hypotheses, community dissimilarities increased significantly with environmental dissimilarity and, to a lesser extent, decreased with ship-borne species transport risks, particularly if the ports had similar environments and stepping-stone risks were considered. Unexpectedly, we found no clear effect of shared biogeography, and that risk metrics incorporating estimates of ballast discharge did not offer more explanatory power than simpler traffic-based risks. Overall, we found that shipping homogenizes eukaryotic communities between ports in predictable ways, which could inform improvements in invasive species policy and management. We demonstrated the usefulness of eDNA metabarcoding and dissimilarity regression for disentangling the drivers of large-scale biodiversity patterns. We conclude by outlining logistical considerations and recommendations for future studies using this approach.Fil: Andrés, Jose. Cornell University. Department Of Ecology And Evolutionary Biology;Fil: Czechowski, Paul. Cornell University. Department Of Ecology And Evolutionary Biology; . University of Otago; Nueva Zelanda. Helmholtz Institute for Metabolic, Obesity and Vascular Research; AlemaniaFil: Grey, Erin. University of Maine; Estados Unidos. Governors State University; Estados UnidosFil: Saebi, Mandana. University of Notre Dame; Estados UnidosFil: Andres, Kara. Cornell University. Department Of Ecology And Evolutionary Biology;Fil: Brown, Christopher. California State University Maritime Academy; Estados UnidosFil: Chawla, Nitesh. University of Notre Dame; Estados UnidosFil: Corbett, James J.. University of Delaware; Estados UnidosFil: Brys, Rein. Research Institute for Nature and Forest; BélgicaFil: Cassey, Phillip. University of Adelaide; AustraliaFil: Correa, Nancy. Ministerio de Defensa. Armada Argentina. Instituto Universitario Naval de la Ara. Escuela de Ciencias del Mar; Argentina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; ArgentinaFil: Deveney, Marty R.. South Australian Research And Development Institute; AustraliaFil: Egan, Scott P.. Rice University; Estados UnidosFil: Fisher, Joshua P.. United States Fish and Wildlife Service; Estados UnidosFil: vanden Hooff, Rian. Oregon Department of Environmental Quality; Estados UnidosFil: Knapp, Charles R.. Daniel P. Haerther Center for Conservation and Research; Estados UnidosFil: Leong, Sandric Chee Yew. National University of Singapore; SingapurFil: Neilson, Brian J.. State of Hawaii Division of Aquatic Resources; Estados UnidosFil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Pfrender, Michael E.. University of Notre Dame; Estados UnidosFil: Pochardt, Meredith R.. M. Rose Consulting; Estados UnidosFil: Prowse, Thomas A. A.. University of Adelaide; AustraliaFil: Rumrill, Steven S.. Oregon Department of Fish and Wildlife; Estados UnidosFil: Scianni, Chris. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Marine Invasive Species Program; Estados UnidosFil: Sylvester, Francisco. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Tamburri, Mario N.. University of Maryland; Estados UnidosFil: Therriault, Thomas W.. Pacific Biological Station; CanadáFil: Yeo, Darren C. J.. National University of Singapore; SingapurFil: Lodge, David M.. Cornell University. Department Of Ecology And Evolutionary Biology

CXCR5⁺ follicular cytotoxic T cells control viral infection in B cell follicles

During unresolved infections, some viruses escape immunological control and establish a persistant reservoir in certain cell types, such as human immunodeficiency virus (HIV), which persists in follicular helper T cells (TFH cells), and Epstein-Barr virus (EBV), which persists in B cells. Here we identified a specialized group of cytotoxic T cells (TC cells) that expressed the chemokine receptor CXCR5, selectively entered B cell follicles and eradicated infected TFH cells and B cells. The differentiation of these cells, which we have called 'follicular cytotoxic T cells' (TFC cells), required the transcription factors Bcl6, E2A and TCF-1 but was inhibited by the transcriptional regulators Blimp1, Id2 and Id3. Blimp1 and E2A directly regulated Cxcr5 expression and, together with Bcl6 and TCF-1, formed a transcriptional circuit that guided TFC cell development. The identification of TFC cells has far-reaching implications for the development of strategies to control infections that target B cells and TFH cells and to treat B cell–derived malignancies

Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p

Beam controller antenna for WiMAX application

Introduce a practical design of an antenna that able to control the radiation beam pattern by using PIN diode and capacitor. The operation of the antenna is an on/off switch that controlled by PIN diode and Direct Current (DC) that supply from an an external source. The proposed antenna was verified to be able to cover the direction of 90 degreess when the DC is turn on. The DC pass through the PIN diode and activate the diode to be functioned as a switch. This proposed antenna is operated at a frequency of 2.3 GHz which is for Worldwide Interoperability for Microwave Access (WiMAX) application that symbolizes in the IEEE 802.16 family. This antenna is designed using a FR-4 substrate material with the dimension is 200 mm×200 mm using Computer Simulation Technology Microwave Studio (CST MWS) simulator software

An evolutionary trade-off between host immunity and metabolism drives fatty liver in male mice

Adaptations to infectious and dietary pressures shape mammalian physiology and disease risk. How such adaptations affect sex-biased diseases remains insufficiently studied. In this study, we show that sex-dependent hepatic gene programs confer a robust (~300%) survival advantage for male mice during lethal bacterial infection. The transcription factor B cell lymphoma 6 (BCL6), which masculinizes hepatic gene expression at puberty, is essential for this advantage. However, protection by BCL6 protein comes at a cost during conditions of dietary excess, which result in overt fatty liver and glucose intolerance in males. Deleting hepatic BCL6 reverses these phenotypes but markedly lowers male survival during infection, thus establishing a sex-dependent trade-off between host defense and metabolic systems. Our findings offer strong evidence that some current sex-biased diseases are rooted in ancient evolutionary trade-offs between immunity and metabolism

Data from: Effects of sampling effort on biodiversity patterns estimated from environmental DNA metabarcoding surveys

Environmental DNA (eDNA) metabarcoding can greatly enhance our understanding of global biodiversity and our ability to detect rare or cryptic species. However, sampling effort must be considered when interpreting results from these surveys. We explored how sampling effort influenced biodiversity patterns and nonindigenous species (NIS) detection in an eDNA metabarcoding survey of four commercial ports. Overall, we captured sequences from 18 metazoan phyla with minimal differences in taxonomic coverage between 18 S and COI primer sets. While community dissimilarity patterns were consistent across primers and sampling effort, richness patterns were not, suggesting that richness estimates are extremely sensitive to primer choice and sampling effort. The survey detected 64 potential NIS, with COI identifying more known NIS from port checklists but 18 S identifying more operational taxonomic units shared between three or more ports that represent un-recorded potential NIS. Overall, we conclude that eDNA metabarcoding surveys can reveal global similarity patterns among ports across a broad array of taxa and can also detect potential NIS in these key habitats. However, richness estimates and species assignments require caution. Based on results of this study, we make several recommendations for port eDNA sampling design and suggest several areas for future research