Growth orientations, rather than heterogeneous growth rates, dominate jaw joint morphogenesis in the larval zebrafish

In early limb embryogenesis, synovial joints acquire specific shapes which determine joint motion and function. The process by which the opposing cartilaginous joint surfaces are moulded into reciprocal and interlocking shapes, called joint morphogenesis, is one of the least understood aspect of joint formation and the cell-level dynamics underlying it are yet to be unravelled. In this research, we quantified key cellular dynamics involved in growth and morphogenesis of the zebrafish jaw joint and synthesised them in a predictive computational simulation of joint development. Cells in larval zebrafish jaw joints labelled with cartilage markers were tracked over a forty-eight hour time window using confocal imaging. Changes in distance and angle between adjacent cell centroids resulting from cell rearrangement, volume expansion and extracellular matrix (ECM) deposition were measured and used to calculate the rate and direction of local tissue deformations. We observed spatially and temporally heterogeneous growth patterns with marked anisotropy over the developmental period assessed. There was notably elevated growth at the level of the retroarticular process of the Meckel's cartilage, a feature known to undergo pronounced shape changes during zebrafish development. Analysis of cell dynamics indicated a dominant role for cell volume expansion in growth, with minor influences from ECM volume increases and cell intercalation. Cell proliferation in the joint was minimal over the timeframe of interest. Synthesising the dynamic cell data into a finite element model of jaw joint development resulted in accurate shape predictions. Our biofidelic computational simulation demonstrated that zebrafish jaw joint growth can be reasonably approximated based on cell positional information over time, where cell positional information derives mainly from cell orientation and cell volume expansion. By modifying the input parameters of the simulation, we were able to assess the relative contributions of heterogeneous growth rates and of growth orientation. The use of uniform rather than heterogeneous growth rates only minorly impacted the shape predictions whereas isotropic growth fields resulted in altered shape predictions. The simulation results suggest that growth anisotropy is the dominant influence on joint growth and morphogenesis. This study addresses the gap of the cellular processes underlying joint morphogenesis, with implications for understanding the aetiology of developmental joint disorders such as developmental dysplasia of the hip and arthrogryposis.

A Combined Atomic and Molecular Probe Characterization of Aromatic Hydrocarbons via PALS and ESR: Methylbenzene

A combined study of one of the simplest aromatic hydrocarbons, i.e., methylbenzene (toluene) (TOL), via the annihilation of an ortho-positronium (o-Ps) probe via positron annihilation lifetime spectroscopy (PALS) and the rotation dynamics of nitroxide spin probe 2,2,6,6-tetramethyl-piperidinyl-1-oxy (TEMPO) using electron spin resonance (ESR) over a wide temperature range, 10–300 K, is reported. The o-Ps lifetime, τ3, and the relative o-Ps intensity, I3, as a function of temperature exhibit changes defining several characteristic PALS temperatures in the slowly and rapidly cooled samples. Similarly, the spectral parameter of TEMPO mobility in TOL, 2Azz‘, and its correlation time, τc, reveal several effects at a set of the characteristic ESR temperatures, which were determined and compared with the PALS results. Finally, the physical origins of the changes in free volume expansion and spin probe mobility are revealed. They are reflected in a series of the mutual coincidences between the characteristic PALS and ESR temperatures and appropriate complementary thermodynamic and dynamic techniques.

Slope analysis for the prediction of fluid responsiveness by a stepwise PEEP elevation recruitment maneuver in mechanically ventilated patients

Objective Assessment of fluid responsiveness is problematic in intensive care unit patients. Lung recruitment maneuvers (LRM) can be used as a functional test to predict fluid responsiveness. We propose a new test to predict fluid responsiveness in mechanically ventilated patients by analyzing the variations in central venous pressure (CVP) and systemic arterial parameters during a prolonged sigh breath LRM without the use of a cardiac output measuring device. Design Prospective observational cohort study. Setting Intensive Care Unit, Saint-Etienne University Central Hospital. Patients Patients under mechanical ventilation, equipped with invasive arterial blood pressure, CVP, pulse contour analysis (PICCO™), requiring volume expansion, with no right ventricular dysfunction. Interventions. None. Measurements and main results CVP, systemic arterial parameters and stroke volume (SV) were recorded during prolonged LRM followed by a 500 mL fluid expansion to asses fluid responsiveness. 25 patients were screened and 18 patients analyzed. 9 patients were responders to volume expansion and 9 were not. Evaluation of hemodynamic parameters suggested the use of a linear regression model. Slopes for systolic arterial pressure, pulse pressure (PP), CVP and SV were all significantly different between responders and non-responders during the pressure increase phase of LRM (STEP-UP) (p = 0.022, p = 0.014, p = 0.006 and p = 0.038, respectively). PP and CVP slopes during STEP-UP were strongly predictive of fluid responsiveness with an AUC of 0.926 (95% CI, 0.78 to 1.00), sensitivity = 100%, specificity = 89% and an AUC = 0.901 (95% CI, 0.76 to 1.00), sensibility = 78%, specificity = 100%, respectively. Combining sensitivity of PP and specificity of CVP, prediction of fluid responsiveness can be achieved with 100% sensitivity and 100% specificity (AUC = 0.96; 95% CI, 0.90 to 1.00). One patient showed inconclusive values using the grey zone approach (5.5%). Conclusions In patients under mechanical ventilation with no right heart dysfunction, the association of PP and CVP slope analysis during a prolonged sigh breath LRM seems to offer a very promising method for prediction of fluid responsiveness without the use and associated cost of a cardiac output measurement device. Trial registration NCT04304521, IRBN902018/CHUSTE. Registered 11 March 2020, Fluid responsiveness predicted by a stepwise PEEP elevation recruitment maneuver in mechanically ventilated patients (STEP-PEEP)

Zn–O–C bonds for efficient electron/ion bridging in ZnSe/C composites boosting sodium ion storage

Metal-selenides are one of the next generation anode materials for sodium ion batteries (SIBs), but suffer from sluggish charge/ion transport, huge volume expansion and aggregation of particles. Herein, ZnSe/C composites...

Anthozoan-like Porous Nanocages with Nano-Cobalt Armed CNTs Multifunctional Layer as Cathode Material for High-stable Na-S Battery

The capacity decay of room-temperature Na-S batteries is mainly caused by the poor electronic conductivity, shuttle effect, and volume expansion of sulfur/polysulfides (NaPSs). Herein, anthozoan-like nitrogen-doped porous carbon nanocages with...

Porous Fe2O3 nanorod-decorated hollow carbon nanofibers for high-rate lithium storage

Transition metal oxides (TMOs) are considered as promising anode materials for lithium-ion batteries in comparison with conventional graphite anode. However, TMO anodes suffer severe volume expansion during charge/discharge process. In this respect, a porous Fe2O3 nanorod-decorated hollow carbon nanofiber (HNF) anode is designed via a combined electrospinning and hydrothermal method followed by proper annealing. FeOOH/PAN was prepared as precursors and sacrificial templates, and porous hollow Fe2O3@carbon nanofiber (HNF-450) composite is formed at 450 °C in air. As anode materials for lithium-ion batteries, HNF-450 exhibits outstanding rate performance and cycling stability with a reversible discharge capacity of 1398 mAh g−1 after 100 cycles at a current density of 100 mA g−1. Specific capacities 1682, 1515, 1293, 987, and 687 mAh g−1 of HNF-450 are achieved at multiple current densities of 200, 300, 500, 1000, and 2000 mA g−1, respectively. When coupled with commercial LiCoO2 cathode, the full cell delivered an outstanding initial charge/discharge capacity of 614/437 mAh g−1 and stability at different current densities. The improved electrochemical performance is mainly attributed to the free space provided by the unique porous hollow structure, which effectively alleviates the volume expansion and facilitates the exposure of more active sites during the lithiation/delithiation process. Graphical abstract Porous Fe2O3 nanorod-decorated hollow carbon nanofibers exhibit outstanding rate performance and cycling stability with a high reversible discharge capacity.

The Role of Silicon in Silicon-Graphite Composite Electrodes Regarding Specific Capacity, Cycle Stability, and Expansion

One promising way of compensating for the repeated volume expansion and contraction of silicon as an anode active material in lithium ion batteries (LIBs) is to embed silicon within a graphite matrix. Silicon-graphite (SiG) composites combine the advantageous properties of graphite, i.e., large electrical conductivity and high structural stability, with the advantageous properties of silicon, i.e., high theoretical capacity. Graphite has a much lower volume expansion upon lithiation (≈ 10%) than pure silicon (≈ 300%) and provides a mechanically stable matrix. Herein, we present an investigation into the electrochemical performance and thickness change behavior of porous SiG anode compositions with silicon contents ranging from 0 wt% to 20 wt%. The electrode composites were studied using two methods: in situ dilatometry for the thickness change investigation and conventional coin cells for the assessment of electrochemical performance. The measurements show that the initial thickness change of SiG electrodes increased significantly with the silicon content, but it leveled off during cycling for all compositions. There appears to be a correlation between silicon content and capacity loss, but no clear correlation between thickness change and capacity loss rate was found.

Circulatory Response to Rapid Volume Expansion and Cardiorespiratory Fitness in Fontan Circulation

The role of dysfunction of the single ventricle in Fontan failure is incompletely understood. We aimed to evaluate hemodynamic responses to preload increase in Fontan circulation, to determine whether circulatory limitations in different locations identified by experimental preload increase are associated with cardiorespiratory fitness (CRF), and to assess the impact of left versus right ventricular morphology. In 38 consecutive patients (median age = 16.6 years, 16 females), heart catheterization was supplemented with a rapid 5-mL/kg body weight volume expansion. Central venous pressure (CVP), ventricular end-diastolic pressure (VEDP), and peak systolic pressure were averaged for 15‒30 s, 45‒120 s, and 4‒6 min (steady state), respectively. CRF was assessed by peak oxygen consumption (VO2peak) and ventilatory threshold (VT). Median CVP increased from 13 mmHg at baseline to 14.5 mmHg (p < 0.001) at steady state. CVP increased by more than 20% in eight patients. Median VEDP increased from 10 mmHg at baseline to 11.5 mmHg (p < 0.001). Ten patients had elevated VEDP at steady state, and in 21, VEDP increased more than 20%. The transpulmonary pressure difference (CVP‒VEDP) and CVP were consistently higher in patients with right ventricular morphology across repeated measurements. CVP at any stage was associated with VO2peak and VT. VEDP after volume expansion was associated with VT. Preload challenge demonstrates the limitations beyond baseline measurements. Elevation of both CVP and VEDP are associated with impaired CRF. Transpulmonary flow limitation was more pronounced in right ventricular morphology. Ventricular dysfunction may contribute to functional impairment after Fontan operation in young adulthood.ClinicalTrials.govidentifier NCT02378857

2D Porous Nb4N5@Nb2C Heterojunctions for High-Performance Li-ion Batteries

Constructing transition metal nitrides (TMNs) with a 2D porous structure is an effective strategy to alleviate their volume expansion and self-aggregation issues, eventually enhancing their electrochemical performance. However, very few studies have been reported up to now. Herein, 2D porous Nb4N5@Nb2C heterojunctions are successfully synthesized from Nb2C MXene precursor by employing a two-step nitridation method in NH3 atmosphere. Owing to the abundant active sites, fast Li-ions diffusion paths, and sufficient buffer space for releasing volume expansion, 2D porous Nb4N5@Nb2C heterojunctions achieve high rate performance and excellent cycling stablility, maintaining 109.2 mAh g-1 at 2 A g-1 after 800 cycles. This work provides a facile strategy for building 2D porous TMNs and their heterojunctions with excellent electrochemical performances.