Elastic and dynamic properties of membrane phase-field models

Phase-field models have been extensively used to study interfacial phenomena, from solidification to vesicle dynamics. In this article, we analyze a phase-field model that captures the relevant physical features that characterize biological membranes. We show that the Helfrich theory of elasticity of membranes can be applied to phase-field models, allowing to derive the expressions of the stress tensor, lateral stress profile and elastic moduli. We discuss the relevance and interpretations of these magnitudes from a phase-field perspective. Taking the sharp-interface limit we show that the membrane macroscopic equilibrium equation can be derived from the equilibrium condition of the phase-field interface. We also study two dynamic models that describe the behaviour of a membrane. From the study of the relaxational behaviour of the membrane we characterize the relevant dynamics of each model, and discuss their applications

Bona fide atypical scrapie faithfully reproduced for the first time in a rodent model

Atypical Scrapie, which is not linked to epidemics, is assumed to be an idiopathic spontaneous prion disease in small ruminants. Therefore, its occurrence is unlikely to be controlled through selective breeding or other strategies as it is done for classical scrapie outbreaks. Its spontaneous nature and its sporadic incidence worldwide is reminiscent of the incidence of idiopathic spontaneous prion diseases in humans, which account for more than 85% of the cases in humans. Hence, developing animal models that consistently reproduce this phenomenon of spontaneous PrP misfolding, is of importance to study the pathobiology of idiopathic spontaneous prion disorders. Transgenic mice overexpressing sheep PrPC with I112 polymorphism (TgShI112, 1–2 × PrP levels compared to sheep brain) manifest clinical signs of a spongiform encephalopathy spontaneously as early as 380 days of age. The brains of these animals show the neuropathological hallmarks of prion disease and biochemical analyses of the misfolded prion protein show a ladder-like PrPres pattern with a predominant 7–10 kDa band. Brain homogenates from spontaneously diseased transgenic mice were inoculated in several models to assess their transmissibility and characterize the prion strain generated: TgShI112 (ovine I112 ARQ PrPC), Tg338 (ovine VRQ PrPC), Tg501 (ovine ARQ PrPC), Tg340 (human M129 PrPC), Tg361 (human V129 PrPC), TgVole (bank vole I109 PrPC), bank vole (I109I PrPC), and sheep (AHQ/ARR and AHQ/AHQ churra-tensina breeds). Our analysis of the results of these bioassays concludes that the strain generated in this model is indistinguishable to that causing atypical scrapie (Nor98). Thus, we present the first faithful model for a bona fide, transmissible, ovine, atypical scrapie prion disease.info:eu-repo/semantics/publishedVersio

Bona fide atypical scrapie faithfully reproduced for the first time in a rodent model

Atypical Scrapie, which is not linked to epidemics, is assumed to be an idiopathic spontaneous prion disease in small ruminants. Therefore, its occurrence is unlikely to be controlled through selective breeding or other strategies as it is done for classical scrapie outbreaks. Its spontaneous nature and its sporadic incidence worldwide is reminiscent of the incidence of idiopathic spontaneous prion diseases in humans, which account for more than 85% of the cases in humans. Hence, developing animal models that consistently reproduce this phenomenon of spontaneous PrP misfolding, is of importance to study the pathobiology of idiopathic spontaneous prion disorders. Transgenic mice overexpressing sheep PrPC with I112 polymorphism (TgShI112, 1–2 × PrP levels compared to sheep brain) manifest clinical signs of a spongiform encephalopathy spontaneously as early as 380 days of age. The brains of these animals show the neuropathological hallmarks of prion disease and biochemical analyses of the misfolded prion protein show a ladder-like PrPres pattern with a predominant 7–10 kDa band. Brain homogenates from spontaneously diseased transgenic mice were inoculated in several models to assess their transmissibility and characterize the prion strain generated: TgShI112 (ovine I112 ARQ PrPC), Tg338 (ovine VRQ PrPC), Tg501 (ovine ARQ PrPC), Tg340 (human M129 PrPC), Tg361 (human V129 PrPC), TgVole (bank vole I109 PrPC), bank vole (I109I PrPC), and sheep (AHQ/ARR and AHQ/AHQ churra-tensina breeds). Our analysis of the results of these bioassays concludes that the strain generated in this model is indistinguishable to that causing atypical scrapie (Nor98). Thus, we present the first faithful model for a bona fide, transmissible, ovine, atypical scrapie prion disease.info:eu-repo/semantics/publishedVersio

Características clínicas y evolución de la infección por SARS-CoV-2 en pacientes con lupus eritematoso sistémico en Argentina: datos del registro nacional SAR-COVID

Introducción: el lupus eritematoso sistémico (LES) es una enfermedad sistémica que se ha asociado a mayor severidad con la infección por SARS-CoV-2. Particularmente la alta actividad de la enfermedad y algunos inmunosupresores se han vinculado a peores desenlaces. Objetivos: describir las características por SARS-CoV-2 en pacientes con LES en Argentina del registro SAR-COVID y establecer los factores asociados a peor desenlace de la misma. Materiales y métodos: estudio observacional. Se incluyeron pacientes con diagnóstico de LES con infección confirmada por SARS-CoV-2 (RT-PCR y/o serología positiva) del registro SAR-COVID. Los datos se recolectaron desde agosto de 2020 hasta marzo de 2022. El desenlace de la infección se midió mediante la escala ordinal de la Organización Mundial de la Salud (EO-OMS). Se definió COVID-19 severo con un valor EO-OMS ≥5. Análisis descriptivo, test T de Student, U de Mann Whitney U, ANOVA, chi2 y Fisher. Regresión logística múltiple. Resultados: se incluyeron 399 pacientes, el 93% de sexo femenino, con una edad media de 40,9 años (DE 12,2). El 39,6% tenía al menos una comorbilidad. Al momento de la infección, el 54,9% recibía glucocorticoides, el 30,8% inmunosupresores y el 3,3% agentes biológicos. La infección por SARS-CoV-2 fue leve en la mayoría de los casos, mientras que un 4,6% tuvo curso severo y/o falleció. Estos últimos presentaban comorbilidades, usaban glucocorticoides y tenían síndrome antifosfolípido (SAF) con mayor frecuencia y mayor actividad de la enfermedad al momento de la infección. En el análisis multivariado, la hipertensión arterial, el diagnóstico de SAF y el uso de glucocorticoides se asociaron a hospitalización severa y/o muerte por COVID-19 (EO-OMS ≥5). Conclusiones: en esta cohorte de pacientes con LES con infección por SARS-CoV-2 confirmada, la mayoría cursó de manera sintomática, un 22,1% fue hospitalizado y un 5% requirió ventilación mecánica. La mortalidad fue cercana al 3%. El diagnóstico de SAF, tener hipertensión arterial y el uso de glucocorticoides se asociaron significativamente con COVID-19 severo

Conocimientos tradicionales relativos a la biodiversidad agrícola

La biodiversidad agrícola, a diferencia de la silvestre, requiere la acción continuada de los agricultores para su conservación, ya que las plantas cultivadas dependen de la intervención humana, con actividades como la selección, la siembra, el abonado, la poda u otras prácticas agrícolas para su supervivencia. Desde la revolución agrícola del Neolítico hasta la actualidad, estas prácticas y conocimientos han ido generando y conservando una gran diversidad, amenazada a partir de la segunda mitad del siglo XX por las causas que se han indicado anteriormente.Peer reviewe

Key Factors Associated With Pulmonary Sequelae in the Follow-Up of Critically Ill COVID-19 Patients

Introduction: Critical COVID-19 survivors have a high risk of respiratory sequelae. Therefore, we aimed to identify key factors associated with altered lung function and CT scan abnormalities at a follow-up visit in a cohort of critical COVID-19 survivors. Methods: Multicenter ambispective observational study in 52 Spanish intensive care units. Up to 1327 PCR-confirmed critical COVID-19 patients had sociodemographic, anthropometric, comorbidity and lifestyle characteristics collected at hospital admission; clinical and biological parameters throughout hospital stay; and, lung function and CT scan at a follow-up visit. Results: The median [p25–p75] time from discharge to follow-up was 3.57 [2.77–4.92] months. Median age was 60 [53–67] years, 27.8% women. The mean (SD) percentage of predicted diffusing lung capacity for carbon monoxide (DLCO) at follow-up was 72.02 (18.33)% predicted, with 66% of patients having DLCO < 80% and 24% having DLCO < 60%. CT scan showed persistent pulmonary infiltrates, fibrotic lesions, and emphysema in 33%, 25% and 6% of patients, respectively. Key variables associated with DLCO < 60% were chronic lung disease (CLD) (OR: 1.86 (1.18–2.92)), duration of invasive mechanical ventilation (IMV) (OR: 1.56 (1.37–1.77)), age (OR [per-1-SD] (95%CI): 1.39 (1.18–1.63)), urea (OR: 1.16 (0.97–1.39)) and estimated glomerular filtration rate at ICU admission (OR: 0.88 (0.73–1.06)). Bacterial pneumonia (1.62 (1.11–2.35)) and duration of ventilation (NIMV (1.23 (1.06–1.42), IMV (1.21 (1.01–1.45)) and prone positioning (1.17 (0.98–1.39)) were associated with fibrotic lesions. Conclusion: Age and CLD, reflecting patients’ baseline vulnerability, and markers of COVID-19 severity, such as duration of IMV and renal failure, were key factors associated with impaired DLCO and CT abnormalities

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016