In Vitro Models of Bacterial Biofilms: Innovative Tools to Improve Understanding and Treatment of Infections

Bacterial infections are a growing concern to the health care systems. Bacteria in the human body are often found embedded in a dense 3D structure, the biofilm, which makes their eradication even more challenging. Indeed, bacteria in biofilm are protected from external hazards and are more prone to develop antibiotic resistance. Moreover, biofilms are highly heterogeneous, with properties dependent on the bacteria species, the anatomic localization, and the nutrient/flow conditions. Therefore, antibiotic screening and testing would strongly benefit from reliable in vitro models of bacterial biofilms. This review article summarizes the main features of biofilms, with particular focus on parameters affecting biofilm composition and mechanical properties. Moreover, a thorough overview of the in vitro biofilm models recently developed is presented, focusing on both traditional and advanced approaches. Static, dynamic, and microcosm models are described, and their main features, advantages, and disadvantages are compared and discussed

Experimental Assessment of Cuff Pressures on the Walls of a Trachea-Like Model Using Force Sensing Resistors: Insights for Patient Management in Intensive Care Unit Settings

The COVID-19 outbreak has increased the incidence of tracheal lesions in patients who underwent invasive mechanical ventilation. We measured the pressure exerted by the cuff on the walls of a test bench mimicking the laryngotracheal tract. The test bench was designed to acquire the pressure exerted by endotracheal tube cuffs inflated inside an artificial model of a human trachea. The experimental protocol consisted of measuring pressure values before and after applying a maneuver on two types of endotracheal tubes placed in two mock-ups resembling two different sized tracheal tracts. Increasing pressure values were used to inflate the cuff and the pressures were recorded in two different body positions. The recorded pressure increased proportionally to the input pressure. Moreover, the pressure values measured when using the non-armored (NA) tube were usually higher than those recorded when using the armored (A) tube. A periodic check of the cuff pressure upon changing the body position and/or when performing maneuvers on the tube appears to be necessary to prevent a pressure increase on the tracheal wall. In addition, in our model, the cuff of the A tube gave a more stable output pressure on the tracheal wall than that of the NA tube

1,4-Bis[2-(prop-1-en­yl)phen­oxy]butane

The mol­ecule of the title compound, C22H26O2, exhibits Ci mol­ecular symmetry with a crystallographic inversion centre at the mid-point of the central C—C bond. A kink in the mol­ecule is defined by the torsion angle of 66.7 (2)° about this central bond of the alkyl bridge

Dementia and Stroke Risk Associated with Brain Artery Luminal Diameters

Background: It is unclear whether brain artery diameters measured on conventional T2-weighted brain MRI images relate to dementia and stroke outcomes across distinct populations. We aimed this study to evaluate the association of T2-weighted brain artery luminal diameters with dementia and stroke in three distinct population‑based studies. Methods: Three longitudinal population-based studies with 8420 adults \u3e40 years old (Northern Manhattan Study [NOMAS] from the United States, and the Rotterdam Study [RS], from the Netherlands, and Three-City, from France) with brain MRI scans obtained between 1999 and 2015. The median follow-up time for clinical events ranged between 7 and 12.5 years. We tested our hypothesis in each cohort separately due to local data‑sharing regulations. The exposure variable was brain carotid and basilar artery luminal diameters measured on MRI axial T2‑weighted scans. Multivariable hazard ratios (HRs) and their 95% confidence intervals (CI) expressed the risk of dementia and stroke (primary outcomes) associated with the lowest (\u3c5th) and highest (\u3e95th) percentiles of the rank‑normalized brain artery diameters compared to a reference group defined as the diameters distributed between the 5th and 95th percentiles. Secondary outcomes included total and vascular mortality, and fatal and nonfatal cardiovascular and coronary end points. Results: Among the three cohorts (mean age ranged from 65 to 73 y, ≥57% women), 335 participants developed dementia and 331 strokes. Compared with the reference group, participants with arterial diameters \u3e95th percentile had a higher risk of dementia (HR range 1.15-4.50) and any stroke (HR range 1.29-2.03). For secondary outcomes, participants with arterial diameters \u3e95th percentile had a consistent higher risk of coronary outcomes, vascular mortality and a composite of any vascular events. The results were less supportive of a higher risk of events among participants with arterial diameters \u3c5th percentile except for vascular mortality. Conclusions: Individuals with dilated brain arteries are at higher risk of dementia and vascular events. Our findings were consistency across distinct populations in spite of using a non-enhanced, conventional T2-weighted MRI sequence. Understanding the underlying physiopathology of the reported associations, particularly with dementia and stroke, might reveal novel vascular contributions to dementi

Physiological and behavioral response of the Asian shore crab, Hemigrapsus sanguineus, to salinity: implications for estuarine distribution and invasion

The invasive Asian shore crab, Hemigrapsus sanguineus, is ubiquitous in the rocky intertidal zone of the western North Atlantic. A likely contributor to this colonization is that H. sanguineus is able to handle a wide range of salinities, and is thus more likely to spread through a greater geographic area of estuaries. This study investigated the salinity effects on this animal by observing survival across a range of salinities, the maintenance of hemolymph osmolality under different salinities, and behavioral preference for and avoidance of salinities. H. sanguineus showed high survival across a broad range of salinities, had little change in hemolymph osmolality over a short-term salinity shock, and behaviorally distinguished between salinities when presented with a choice, under both acclimation salinities of 5 PSU or 35 PSU. Such results suggest H. sanguineus has a hardiness for the rapid changes in salinity that happen in the intertidal zone, yet is capable of physically moving to a more optimal salinity. This enhances their competitiveness as an invader, particularly surviving lower salinities that present challenges during high-precipitation events in rocky intertidal areas, and partially explains this species’ dominance in this habitat type

Reduced phase space of heat-carrying acoustic phonons in single-crystalline InTe

Chalcogenide semiconductors and semimetals are a fertile class of efficient thermoelectric materials, which, in most cases, exhibit very low lattice thermal conductivity κph despite lacking a complex crystal structure such as the tetragonal binary compound InTe. Our measurements of κph(T) in single-crystalline InTe along the c axis show that κph exhibits a smooth temperature dependence upon cooling to about 50 K, the temperature below which a strong rise typical for dielectric compounds is observed. Using a combination of first-principles calculations, inelastic neutron scattering (INS), and low-temperature specific heat and transport properties measurements on single-crystalline InTe, we show that the phonon spectrum exhibits well-defined acoustic modes, the energy dispersions of which are constrained to low energies due to distributions of dispersionless, optical modes, which are responsible for a broad double peak structure in the low-temperature specific heat. The latter are assigned to the dynamics of In+ cations in tunnels formed by edge-sharing (In3+Te42−)− tetrahedra chains, the atomic thermal displacement parameters of which, probed as a function of temperature by means of single-crystal x-ray diffraction, suggest the existence of a complex energy potential. Indeed, the In+-weighted optical modes are not observed by INS, which is ascribed to the anharmonic broadening of their energy profiles. While the low κph value of 1.2Wm−1K−1 at 300 K originates from the limited energy range available for acoustic phonons, we show that the underlying mechanism is specific to InTe and argue that it is likely related to the presence of local disorder induced by the In+ sit

Genetic determinants of cortical structure (thickness, surface area and volumes) among disease free adults in the CHARGE Consortium

Cortical thickness, surface area and volumes (MRI cortical measures) vary with age and cognitive function, and in neurological and psychiatric diseases. We examined heritability, genetic correlations and genome-wide associations of cortical measures across the whole cortex, and in 34 anatomically predefined regions. Our discovery sample comprised 22,824 individuals from 20 cohorts within the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium and the United Kingdom Biobank. Significant associations were replicated in the Enhancing Neuroimaging Genetics through Meta-analysis (ENIGMA) consortium, and their biological implications explored using bioinformatic annotation and pathway analyses. We identified genetic heterogeneity between cortical measures and brain regions, and 160 genome-wide significant associations pointing to wnt/β-catenin, TGF-β and sonic hedgehog pathways. There was enrichment for genes involved in anthropometric traits, hindbrain development, vascular and neurodegenerative disease and psychiatric conditions. These data are a rich resource for studies of the biological mechanisms behind cortical development and aging