29 research outputs found
Disordering effects of colour in a system of coupled Brownian motors: phase diagram and anomalous-to-normal hysteresis transition
A system of periodically coupled nonlinear phase oscillators submitted to
both additive and multiplicative white noises has been recently shown to
exhibit ratchetlike transport, negative zero-bias conductance, and anomalous
hysteresis. These features stem from the "asymmetry" of the stationary
probability distribution function, arising through a noise-induced
nonequilibrium phase transition which is "reentrant" as a function of the
multiplicative noise intensity. Using an explicit mean-field approximation we
analyze the effect of the multiplicative noises being coloured, finding a
contraction of the ordered phase (and a reentrance as a function of the
coupling) on one hand, and a shift of the transition from anomalous to normal
hysteresis inside this phase on the other.Comment: Invited Talk LAWNP01, Proceedings to be published in Physica D,
RevTex, 9 pgs, 5 figure
Continuous population-level monitoring of SARS-CoV-2 seroprevalence in a large European metropolitan region.
Effective public health measures against SARS-CoV-2 require granular knowledge of population-level immune responses. We developed a Tripartite Automated Blood Immunoassay (TRABI) to assess the IgG response against three SARS-CoV-2 proteins. We used TRABI for continuous seromonitoring of hospital patients and blood donors (n = 72'250) in the canton of Zurich from December 2019 to December 2020 (pre-vaccine period). We found that antibodies waned with a half-life of 75 days, whereas the cumulative incidence rose from 2.3% in June 2020 to 12.2% in mid-December 2020. A follow-up health survey indicated that about 10% of patients infected with wildtype SARS-CoV-2 sustained some symptoms at least twelve months post COVID-19. Crucially, we found no evidence of a difference in long-term complications between those whose infection was symptomatic and those with asymptomatic acute infection. The cohort of asymptomatic SARS-CoV-2-infected subjects represents a resource for the study of chronic and possibly unexpected sequelae
Whole-genome sequencing reveals host factors underlying critical COVID-19
Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genesâincluding reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)âin critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease
Prion Infections and Anti-PrP Antibodies Trigger Converging Neurotoxic Pathways
Prions induce lethal neurodegeneration and consist of PrPSc, an aggregated conformer of the cellular prion protein PrPC. Antibody-derived ligands to the globular domain of PrPC (collectively termed GDL) are also neurotoxic. Here we show that GDL and prion infections activate the same pathways. Firstly, both GDL and prion infection of cerebellar organotypic cultured slices (COCS) induced the production of reactive oxygen species (ROS). Accordingly, ROS scavenging, which counteracts GDL toxicity in vitro and in vivo, prolonged the lifespan of prion-infected mice and protected prion-infected COCS from neurodegeneration. Instead, neither glutamate receptor antagonists nor inhibitors of endoplasmic reticulum calcium channels abolished neurotoxicity in either model. Secondly, antibodies against the flexible tail (FT) of PrPC reduced neurotoxicity in both GDL-exposed and prion-infected COCS, suggesting that the FT executes toxicity in both paradigms. Thirdly, the PERK pathway of the unfolded protein response was activated in both models. Finally, 80% of transcriptionally downregulated genes overlapped between prion-infected and GDL-treated COCS. We conclude that GDL mimic the interaction of PrPSc with PrPC, thereby triggering the downstream events characteristic of prion infection. © 2015 Herrmann et al
Aspectos fĂsico-quĂmicos e microbiolĂłgicos de grĂŁos de soja tratados com ĂĄcidos orgĂąnicos e seus sais Physical-chemical and microbiological aspects of soybean grain treated with organic acid and their salts
Este trabalho teve por objetivo avaliar os parĂąmetros microbiolĂłgicos e fĂsico-quĂmicos do grĂŁo de soja (Glycine max L.) desativado, tratado com trĂȘs diferentes dosagens (2, 4 e 6L t-1) de uma mistura de ĂĄcidos orgĂąnicos e seus sais (AOS), com a função de aditivo antifĂșngico. O ensaio teve uma duração de 90 dias, em que foram feitas a contagem de bolores e leveduras (UFC g-1), e a identificação dos gĂȘneros fĂșngicos, da umidade (U), da atividade de ĂĄgua (AA), do Ăndice de perĂłxido (IP) e do Ăndice de acidez (IA). As anĂĄlises foram realizadas em triplicata, em intervalos de 15 dias entre cada anĂĄlise, atĂ© o 60o dia de avaliação e depois no 90o dia do experimento. Verificou-se aumento na UFC g-1 nas doses de 2 e 4L t-1, bem como mudança nos gĂȘneros fĂșngicos encontradas nestes tratamentos a cada avaliação, diferentemente da baixa UFC g-1 e da identificação de gĂȘneros na dose de 6L t-1. Os valores de U e AA mantiveram-se acima dos padrĂ”es recomendados de 14% e 0,70, respectivamente em todos os tratamentos e avaliaçÔes. O IP aumentou significativamente a partir do 45o dia de avaliação no controle e a partir do 60o dia nos demais tratamentos. O IA nĂŁo variou significativamente durante o perĂodo de avaliação. Conclui-se que a dosagem de 6L t-1 foi eficiente na proteção antifĂșngica desta matĂ©ria-prima.<br>This research had the objective to evaluate microbiological and physical-chemical parameters of deactivated soybean grain (Glycine max L.) treated with three different dosages (2, 4 and 6L t-1) of organic acids and their salts mixture (AOS), as an antifungical additive. The assay had a duration of 90 days, where executed fungi count (UFC g-1), fungi specie identification, humidity (U), activity of water (AA), peroxide value (IP) and acidity value (IA). The analyses were carried out in triplicate, in intervals of 15 days among analysis, until 60th day of evaluation and, at the 90th day of evaluation. There were increases in the UFC g-1 in dosages of 2 and 4L t-1, as well a change in fungi species found in these treatment at each evaluation, distinguished of low UFC g-1 and fungi species in dosage of 6L t-1. The values of U and AA were above of recommended patterns of 14% and 0.70, respectively for all treatments and evaluations. The IP increased significative from 45th day of evaluation in control and from 60th day in other treatments. The IA had no significative variation during the period of evaluation. The dosage of 6L t-1 was efficient in the antifungical protection of this raw material