pH-induced conformational changes in the selectivity filter of a potassium channel lead to alterations in its selectivity and permeation properties.

The Selectivity Filter (SF) in tetrameric K channels, has a highly conserved sequence, TVGYG, at the extracellular entry to the channel pore region. There, the backbone carbonyl oxygens from the SF residues, create a stack of K binding sites where dehydrated K binds to induce a conductive conformation of the SF. This increases intersubunit interactions and confers a higher stability to the channel against thermal denaturation.

Coefficients in Taylor's law increase with the time scale of water clarity measurements in a global suite of lakes.

Identifying the scaling rules describing ecological patterns across time and space is a central challenge in ecology. Taylor's law of fluctuation scaling, which states that the variance of a population's size or density is proportional to a positive power of the mean size or density, has been widely observed in population dynamics and characterizes variability in multiple scientific domains. However, it is unclear if this phenomenon accurately describes ecological patterns across many orders of magnitude in time, and therefore links otherwise disparate observations.

The MAASWERP Study: An International, Comparative Case Study on Measuring Biomechanics of the Aged Murine Aorta.

Introduction: Arterial stiffening is a hallmark of vascular ageing, and unravelling its underlying mechanisms has become a central theme in the field of cardiovascular disease. While various techniques and experimental setups are accessible for investigating biomechanics of blood vessels both in vivo and ex vivo, comparing findings across diverse methodologies is challenging.

Methods: Arterial stiffness in the aorta of adult (5 months) and aged (24 months) wild-type C57Bl/6J mice was measured in vivo, after which ex vivo biomechanical evaluation was performed using the Rodent Oscillatory Tension Setup to study Arterial Compliance (ROTSAC; University of Antwerp, Belgium) and the DynamX setup (Maastricht University, The Netherlands).

Interpretation of intra-operative strain differences in ascending thoracic aortic repair patients.

Local biaxial deformation plays a pivotal role in evaluating the tissue state of the ascending aorta and in driving intramural cell-mediated tissue remodeling. Unfortunately, the absence of anatomical markers on the ascending aorta presents challenges in capturing deformation. Utilizing our established intra-operative biaxial strain measurement method, we delineated local biaxial deformation characteristics in patients undergoing aortic valve replacement and coronary artery bypass graft surgery recipients (n = 20), and Aortic Repair surgery patients (n = 47).

Beat-to-beat variability of aortic pulse wave velocity: implications for aortic stiffness measurements.

Objectives: Aortic pulse wave velocity (aPWV) predicts cardiovascular risk. Being the reference method for aortic stiffness evaluation, invasive aPWV is also recommended for validation of noninvasive devices. Because of intrinsic haemodynamic variability and processing issues, aPWV shows beat-to-beat variability.

Transient Amplification of Broken Symmetry in Elastic Snap-Through.

A snap-through bifurcation occurs when a bistable structure loses one of its stable states and moves rapidly to the remaining state. For example, a buckled arch with symmetrically clamped ends can snap between an inverted and a natural state as the ends are released. A standard linear stability analysis suggests that the arch becomes unstable to asymmetric perturbations.

Instability in Computational Models of Vascular Smooth Muscle Cell Contraction.

Purpose: Through their contractile and synthetic capacity, vascular smooth muscle cells (VSMCs) can regulate the stiffness and resistance of the circulation. To model the contraction of blood vessels, an active stress component can be added to the (passive) Cauchy stress tensor. Different constitutive formulations have been proposed to describe this active stress component.

Effect of rapid cooling, frozen storage, and thawing on the passive viscoelastic properties and structure of the rat aorta.

Biological tissues decay over time after harvesting, which alters their biomechanical properties. This poses logistical challenges for studies investigating passive arterial biomechanics as tissues need to be characterized shortly after excision. Freezing and cryopreservation methods can help alleviate the need for biomechanical testing of fresh tissue in human ex vivo studies.

Pre-Pandemic Predictivity of Anxious-Depressive Symptoms in Post-Surgical Traumatic Distress in Hysterectomy for Benign Disease and COVID-19 Outbreak: A Case-Control Study.

The severe acute respiratory syndrome coronavirus (SARS-CoV-2) pandemic led to several needed containment measures that conditioned the onset of depressive, anxiety, and post-traumatic stress symptoms in the population. These symptoms, especially if not diagnosed and treated, can also occur in patients undergoing medical care or surgery, with a high impact on people's lives and causing low adherence to treatment. The study evaluates whether the spread of the coronavirus disease 2019 (COVID-19) worsened the onset of post-surgical distress and symptoms of anxiety and depression in a population undergoing hysterectomy for benign disease during the pandemic era, comparing it with a population with the same characteristics but recruited before COVID-19.

Significance of Dynamic Axial Stretching on Estimating Biomechanical Behavior and Properties of the Human Ascending Aorta.

Contrary to most vessels, the ascending thoracic aorta (ATA) not only distends but also elongates in the axial direction. The purpose of this study is to investigate the biomechanical behavior of the ascending thoracic aorta (ATA) in response to dynamic axial stretching during the cardiac cycle. In addition, the implications of neglecting this dynamic axial stretching when estimating the constitutive model parameters of the ATA are investigated.

Surgical Outcomes and Complications of Myomectomy: A Prospective Cohort Study.

Study Objective: To investigate postoperative surgical and non-surgical complications that occur within 30 days following myomectomy procedures, whether laparoscopic or via open surgery.

Design: Prospective cohort study SETTING: Del Ponte Women's and Children's Hospital, Varese, Italy.

Patients: Women undergoing myomectomy either with laparoscopic or open surgery from July 2020 to June 2023 INTERVENTIONS: Data of consecutive patients who underwent abdominal myomectomy procedures, either via laparoscopy or open abdominal surgery were collected.

Steady-state and time-resolved fluorescent methodologies to characterize the conformational landscape of the selectivity filter of K channels.

A variety of equilibrium and non-equilibrium methods have been used in a multidisciplinary approach to study the conformational landscape associated with the binding of different cations to the pore of potassium channels. These binding processes, and the conformational changes resulting therefrom, modulate the functional properties of such integral membrane properties, revealing these permeant and blocking cations as true effectors of such integral membrane proteins. KcsA, a prototypic K channel from Streptomyces lividans, has been extensively characterized in this regard.

Pharmacological modulation of vascular ageing: A review from VascAgeNet.

Vascular ageing, characterized by structural and functional changes in blood vessels of which arterial stiffness and endothelial dysfunction are key components, is associated with increased risk of cardiovascular and other age-related diseases. As the global population continues to age, understanding the underlying mechanisms and developing effective therapeutic interventions to mitigate vascular ageing becomes crucial for improving cardiovascular health outcomes. Therefore, this review provides an overview of the current knowledge on pharmacological modulation of vascular ageing, highlighting key strategies and promising therapeutic targets.

Aging and Vascular Disease: A Multidisciplinary Overview.

Vascular aging, i.e., the deterioration of the structure and function of the arteries over the life course, predicts cardiovascular events and mortality.

Anionic Phospholipids Shift the Conformational Equilibrium of the Selectivity Filter in the KcsA Channel to the Conductive Conformation: Predicted Consequences on Inactivation.

Here, we report an allosteric effect of an anionic phospholipid on a model K channel, KcsA. The anionic lipid in mixed detergent-lipid micelles specifically induces a change in the conformational equilibrium of the channel selectivity filter (SF) only when the channel inner gate is in the open state. Such change consists of increasing the affinity of the channel for K, stabilizing a conductive-like form by maintaining a high ion occupancy in the SF.

Constituent-based quasi-linear viscoelasticity: a revised quasi-linear modelling framework to capture nonlinear viscoelasticity in arteries.

Arteries exhibit fully nonlinear viscoelastic behaviours (i.e. both elastically and viscously nonlinear).

Education as a tool of social equality?

Do political parties approach education with different social policy aims? We argue that while parties have adopted a common language of equality as an aim of education, they draw on different conceptions of it linked to diverging social projects. To make this argument, we first normatively distinguish education as a tool for creating equal opportunity, equal outcomes, and representational diversity. We then draw on an original dataset coding the educational content in the political manifestos of the largest center-left and center-right party across 19 Western democracies from 1950 to present.

Tri-layered constitutive modelling unveils functional differences between the pig ascending and lower thoracic aorta.

The arterial wall's tri-layered macroscopic and layer-specific microscopic structure determine its mechanical properties, which vary at different arterial locations. Combining layer-specific mechanical data and tri-layered modelling, this study aimed to characterise functional differences between the pig ascending (AA) and lower thoracic aorta (LTA). AA and LTA segments were obtained for n=9 pigs.

Detectable Bias between Vascular Ultrasound Echo-Tracking Systems: Relevance Depends on Application.

The Esaote MyLab70 ultrasound system has been extensively used to evaluate arterial properties. Since it is reaching end-of-service-life, ongoing studies are forced to seek an alternative, with some opting for the Esaote MyLabOne. Biases might exist between the two systems, which, if uncorrected, could potentially lead to the misinterpretation of results.

Curvature-driven instabilities in thin active shells.

Spontaneous material shape changes, such as swelling, growth or thermal expansion, can be used to trigger dramatic elastic instabilities in thin shells. These instabilities originate in geometric incompatibility between the preferred extrinsic and intrinsic curvature of the shell, which may be modified by active deformations through the thickness and in plane, respectively. Here, we solve the simplest possible model of such instabilities, which assumes the shells are shallow, thin enough to bend but not stretch, and subject to homogeneous preferred curvatures.