Recovering the activity parameters of an active fluid confined in a sphere.

The properties of an active fluid, for example, a bacterial bath or a collection of microtubules and molecular motors, can be accessed through the dynamics of passive particle probes. Here, in the perspective of analyzing experimental situations of confinement in droplets, we consider the kinematics of a negatively buoyant probe particle in an active fluid, both confined within a spherical domain. The active bath generates a fluctuating flow that pushes the particle with a velocity that is modeled as a colored stochastic noise, characterized by two parameters, the intensity and memory time of the active flow.

Accumulation and depletion of E. coli in surfaces mediated by curvature.

Can topography be used to control bacteria accumulation? We address this question in the model system of smooth-swimming and run-and-tumble Escherichia coli swimming near a sinusoidal surface, and show that the accumulation of bacteria is determined by the characteristic curvature of the surface. For low curvatures, cells swim along the surface due to steric alignment and are ejected from the surface when they reach the peak of the sinusoid. Increasing curvature enhances this effect and reduces the density of bacteria in the curved surface.

Between the personal and the political: life experiences during the covid-19 pandemic in Tucumán, Argentina, 2020-2022.

This article analyzes feelings, experiences, practices, and actions that underlie the meanings attributed to the covid-19 pandemic. Based on a case study located in the province of Tucumán (Argentina), a mixed-methods investigation was developed, interested in capturing life experiences. Discourse analysis show the resignification of life itself, the valorization of close ties, community social capital, the State and politics.

Salir Adelante: Social capital and resilience during the Covid-19 pandemic in Argentina.

The Covid-19 pandemic has stimulated new appraisals of how social cohesion, including neighborhood-level social capital, fosters resilience in the face of crisis. Several studies suggest better health outcomes in neighborhoods with higher level of social capital, in general and during the pandemic. Building on a growing body of research which suggests that those who live in close-knit neighborhoods have fared better during the pandemic, this article analyzes how social capital influences individual and collective perceptions and attitudes about the experiences of the Covid-19 pandemic in Tucumán, Argentina.

Study of the interaction of folic acid-modified gold nanorods and fibrinogen through microfluidics: implications for protein adsorption, incorporation and viability of cancer cells.

Gold nanoparticles (GNPs) are an attractive nanomaterial for potential applications in therapy and diagnostics due to their capability to direct toward specific sites in the organism. However, when exposed to plasma, GNPs can interact with different biomolecules that form a dynamic nano-bio interface called a "protein corona" (PC). Remarkably, the PC could affect multiple biological processes, such as cell targeting and uptake, cytotoxicity, and nanoparticle (NP) clearance.

Magnitude and spatial distribution of food and nutrition security during the COVID-19 pandemic in Tucumán (Argentina).

Objective: To describe the magnitude and spatial distribution of household food and nutrition security (FNS) during the COVID-19 pandemic in Tucumán (Argentina) and identify factors associated with food insecurity.

Methods: During April and May 2020 a cross-sectional quantitative study was performed. Data from 3915 households were analyzed.

Local details versus effective medium approximation: A study of diffusion in microfluidic random networks made from Voronoi tessellations.

We measured the effective diffusion coefficient in regions of microfluidic networks of controlled geometry using the fluorescence recovery after photobleaching (FRAP) technique. The geometry of the networks was based on Voronoi tessellations, and had varying characteristic length scale and porosity. For a fixed network, FRAP experiments were performed in regions of increasing size.

Bacteria driving droplets.

We confine a dense suspension of motile Escherichia coli inside a spherical droplet in a water-in-oil emulsion, creating a "bacterially" propelled droplet. We show that droplets move in a persistent random walk, with a persistence time τ∼ 0.3 s, a long-time diffusion coefficient D∼ 0.

Magnetotactic bacteria in a droplet self-assemble into a rotary motor.

From intracellular protein trafficking to large-scale motion of animal groups, the physical concepts driving the self-organization of living systems are still largely unraveled. Self-organization of active entities, leading to novel phases and emergent macroscopic properties, recently shed new light on these complex dynamical processes. Here we show that under the application of a constant magnetic field, motile magnetotactic bacteria confined in water-in-oil droplets self-assemble into a rotary motor exerting a torque on the external oil phase.

Nutritional transition in schoolchildren from Tucumán, Argentina: A cross-sectional analysis of nutritional status and body composition.

Objective: The aim of this article was to describe the nutritional status and body composition of schoolchildren from Tucumán (Argentina) and analyze variations according to sex, area of residence, and socioeconomic status (SES).

Methods: A cross-sectional study was performed in 1948 schoolchildren aged 8.0 to 11.

[Overweight, obesity and perceived health in contexts of poverty in Tucumán, Argentina].

In contexts in which poverty compromises children's health and quality of life, the study of perceived health allows for the identification of aspects of quality of life affected by overweight and obesity. From this perspective, the objectives of this study were: 1) to determine the prevalence of overweight and obesity in schoolchildren aged 8-12 years living in contexts of poverty, 2) to describe and compare the perception of health of children according to the presence or absence of overweight and obesity, and 3) to identify possible factors associated with low quality of life related to health. A quantitative and cross-sectional study was conducted.

[Measurement of rest energy expanditure in pediatric oncological patients: concordance between indirect calorimetry and predictive equations].

Introduction: in childhood cancer, the disease impacts resting energy expenditure (GER) in a way that is not estimable by predictive equations.

Objective: the aim of this study is to determine the concordance between the measurement of resting energy expenditure (REE) by indirect calorimetry in pediatric oncology patients versus the World Health Organization (WHO) and Schofield predictive equations.

Method: cross-sectional study in children aged 5-15 years receiving chemotherapy, in outpatient Clínica Las Condes and Hospital Dr.

Perceived health and its relation with macrosocial and individual factors in children from two departments of Tucumán, Argentina.

Introduction: The assessment of health-related quality of life (HRQoL) during childhood favors the identification of factors that affect growth and development. The objectives of this study were: a) to describe the HRQoL in children between 8.0 and 11.

Incidence and prognosis of ventilator-associated tracheobronchitis (TAVeM): a multicentre, prospective, observational study.

Background: Ventilator-associated tracheobronchitis has been suggested as an intermediate process between tracheobronchial colonisation and ventilator-associated pneumonia in patients receiving mechanical ventilation. We aimed to establish the incidence and effect of ventilator-associated tracheobronchitis in a large, international patient cohort.

Methods: We did a multicentre, prospective, observational study in 114 intensive care units (ICU) in Spain, France, Portugal, Brazil, Argentina, Ecuador, Bolivia, and Colombia over a preplanned time of 10 months.

Effect of confinement on the deformation of microfluidic drops.

We study the deformation of drops squeezed between the floor and ceiling of a microchannel and subjected to a hyperbolic flow. We observe that the maximum deformation of drops depends on both the drop size and the rate of strain of the external flow and can be described with power laws with exponents 2.59±0.

Time-resolved temperature rise in a thin liquid film due to laser absorption.

The temperature increase of a thin water layer is investigated, both experimentally and numerically, when the layer is heated by an infrared laser. The laser is focused to a waist of 5.3 microm inside a 28 microm gap that contains fluorescent aqueous solutions between two glass slides.

Resonant frequency shifts induced by a large spherical object in an air-filled acoustic cavity.

Acoustic resonances are modified when objects are introduced into a chamber. The magnitude of these changes depends on the object position, size, and shape, as well as on its acoustic properties. Here, an experimental study concerning the resonant frequency shifts induced by a solid spherical object in a quasi-one-dimensional air-filled acoustic cavity is reported.