Critical-point wedge filling and critical-point wetting.

For simple fluids adsorbed at a planar solid substrate (modeled as an inert wall) it is known that critical-point wetting, that is, the vanishing of the contact angle θ at a temperature T_{w} lying below that of the critical point T_{c}, need not occur. While critical-point wetting necessarily happens when the wall-fluid and fluid-fluid forces have the same range (e.g., both are long ranged or both short ranged) nonwetting gaps appear in the surface phase diagram when there is an imbalance between the ranges of these forces. Here we show that despite this, the convergence of the lines of constant contact angle, 0<θ<π, to an ordinary surface phase transition at T_{c}, means that fluids adsorbed in wedges (and cones) always exhibit critical-point filling (wedge wetting or wedge drying) regardless of the range and imbalance of the forces. We illustrate the necessity of critical-point filling, even in the absence of critical-point wetting, using a microscopic model density functional theory of fluid adsorption in a right angle wedge, with dispersion and also retarded dispersionlike wall-fluid forces. The location and order of the filling phase boundaries are determined and shown to be in excellent agreement with exact thermodynamic requirements and also predictions for critical singularities based on interfacial models.

Critical behaviour of the contact angle within nonwetting gaps.

Recent density functional theory and simulation studies of fluid adsorption near planar walls in systems where the wall-fluid and fluid-fluid interactions have different ranges, have shown that critical point wetting may not occur and instead nonwetting gaps appear in the surface phase diagram, separating lines of wetting and drying transitions, that extend up to the critical temperatureTc. Here we clarify the features of the surface phase diagrams that are common, regardless of the range and balance of the forces, showing, in particular, that the lines of temperature driven wetting and drying transitions, as well as lines of constant contact angleπ>θ>0, always converge to an ordinary surface phase transition atTc. When nonwetting gaps appear the contact angle either vanishes or tends toπast≡(Tc-T)/Tc→0. More specifically, when the wall-fluid interaction is long-ranged (dispersion-like) and the fluid-fluid short-ranged we estimateπ-θ∝t0.16, compared withθ∝t0.77when the wall-fluid interaction is short-ranged and the fluid-fluid dispersion-like, allowing for the effects of bulk critical fluctuations. The universal convergence of the lines of constant contact angle implies that critical point filling always occurs for fluids adsorbed in wedges.

Influence of improved antenatal detection on the outcomes of complete atrioventricular block diagnosed in fetal-neonatal life and childhood periods - a single-centre experience in South Wales for 55 years.

OBJECTIVE: This study aimed to analyse the influence of improved antenatal detection on the course, contemporary outcomes, and mortality risk factors of the complete atrioventricular block during fetal-neonatal and childhood periods in South Wales. METHODS: The clinical characteristics and outcomes of complete atrioventricular block in patients without structural heart disease at the University Hospital of Wales from January 1966 to April 2021 were studied. Patients were divided into two groups according to their age at diagnosis: I-fetal-neonatal and II-childhood. Contemporary outcomes during the post-2001 era were compared with historical data preceding fetal service development and hence earlier detection. RESULTS: There were 64 patients: 26 were identified in the fetal-neonatal period and the remaining 38 in the childhood period. Maternal antibodies/systemic lupus erythematosus disease (anti-Ro/Sjögren's-syndrome-related Antigen A and/or anti-La/Sjögren's-syndrome-related Antigen B) were present in 15 (57.7%) of the fetal-neonatal. Fetal/neonatal and early diagnosis increased after 2001 with an incidence of 1:25000 pregnancies. Pacemaker implantation was required in 34 patients, of whom 13 were diagnosed in the fetal-neonatal group. Survival rates in cases identified before 2001 were at 96.3% (26/27), whereas it was 83.8% (31/37) in patients diagnosed after 2001 (P > 0.05). Other mortality risk factors comprised a lower gestational week at birth, maternal antibodies, and an average ventricular heart rate of < 55 bpm. CONCLUSIONS: Fetal diagnosis of complete atrioventricular block is still portends high fetal and neonatal mortality and morbidity despite significantly improved antenatal detection after 2001. Pacemaker intervention is needed earlier in the fetal-neonatal group. Whether routine antenatal medical treatment might alter this outcome calls for further prospective multicentre studies.

Understanding the use of oxygen delivery devices.

Many nurses will care for a patient who requires oxygen therapy, either to treat an acute respiratory condition, such as a lung infection, or a chronic condition, such as chronic obstructive pulmonary disease. This article discusses the physiology of gaseous exchange and provides an overview of some of the main respiratory conditions that may result in the need for oxygen therapy. The author also describes the oxygen delivery devices commonly used in clinical practice, such as simple face masks and nasal cannulas, to assist nurses in selecting the most appropriate device.

Surface Phase Diagrams for Wetting with Long-Ranged Forces.

Recent density functional theory and simulation studies of wetting and drying transitions in systems with long-ranged, dispersionlike forces, away from the near vicinity of the bulk critical temperature T_{c}, have questioned the generality of the global surface phase diagrams for wetting, due to Nakanishi and Fisher, pertinent to systems with short-ranged forces. We extend these studies deriving fully analytic results which determine the surface phase diagrams over the whole temperature range up to T_{c}. The phase boundaries, order of, and asymmetry between the lines of wetting and drying transitions are determined exactly showing that they always converge to an ordinary surface critical point. We highlight the importance of lines of maximally multicritical wetting and drying transitions, for which we determine the exact critical singularities.

Correction: Abrupt onset of the capillary-wave spectrum at wall-fluid interfaces.

Correction for 'Abrupt onset of the capillary-wave spectrum at wall-fluid interfaces' by Andrew O. Parry et al., Soft Matter, 2023, 19, 5668-5673, https://doi.org/10.1039/D3SM00761H.

Abrupt onset of the capillary-wave spectrum at wall-fluid interfaces.

Surfaces between 3D solids and fluids exhibit a wide variety of phenomena both at equilibrium, such as roughening transitions, interfacial fluctuations and wetting, and also out-of-equilibrium, such as the surface growth of driven interfaces. These phenomena are described very successfully using lower dimensional (2D) effective models which focus on the physics associated with emergent mesoscopic lengths scales, parallel to the interface, where the 2D-like behaviour is physically transparent. However, the precise conditions under which this dimensional reduction is justifiable have remained unclear. Here we show that, for a wall-fluid interface, a dimensional reduction from 3D-like to 2D-like behaviour - identified via the decay of density correlations - occurs abruptly at a specific value of the contact angle, and indicates the beginning of interfacial-like 2D behaviour and the spontaneous onset of the capillary-wave spectrum. The reduction from 3D to 2D is characterised by the divergence of a correlation length perpendicular to the interface revealing a morphological change in the nature of density correlations. Counter-intuitive effects occur, including that 3D behaviour can persist up to the wetting temperature and also that 2D behaviour can begin when no wetting layer is present and the adsorption is negative.

Off-pump injectable versus on-pump conventional tissue valves for pulmonary valve replacement: the injectable valve implantation randomised trial (INVITE).

OBJECTIVES: To assess the effectiveness of injectable tissue pulmonary valve compared with standard pulmonary valve in patients requiring pulmonary valve replacement surgery. DESIGN: A multicentre, single-blind, parallel two-group randomised controlled trial. Participants were blind to their allocation. Follow-up continued for 6 months. Randomised allocations were generated by a computer using block randomisation, stratified by centre. SETTING: Two National Health Service secondary care centres in the UK. PARTICIPANTS: People aged 12-80 years requiring pulmonary valve replacement. INTERVENTIONS: Participants were randomly allocated (1:1 ratio) to injectable pulmonary valve replacement (IPVR) without cardiopulmonary bypass (CPB) or standard pulmonary valve replacement (SPVR) with CPB. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was chest drainage volume over the first 24 hours after surgery. Secondary outcomes included in-hospital clinical outcomes; valve and heart function 6 months postsurgery and health-related quality of life 6 weeks and 6 months postsurgery. RESULTS: Nineteen participants agreed to take part. Eleven were allocated to IPVR and eight to SPVR. The trial was stopped before the target sample size of 60 participants was reached due to challenges in recruitment. The primary analysis includes all randomised participants; there were no withdrawals. Chest drain volume 24 hours after surgery was on average 277.6 mL lower with IPVR (IPVR mean 340.0 mL; SPVR mean 633.8 mL; mean difference, -277.6; 95% CI, -484.0 to -71.2; p=0.005). There were no statistically significant differences in time to readiness for extubation (p=0.476), time to fitness for discharge (p=0.577) and time to first discharge from the intensive care unit (p=0.209). Six participants with IPVR required CPB. Safety profiles and quality of life scores were similar. CONCLUSIONS: IPVR reduced chest drain volume despite >50% of participants requiring CPB. There was no evidence of any other benefit of IPVR. TRIAL REGISTRATION NUMBER: ISRCTN23538073.

Warm versus cold blood cardioplegia in paediatric congenital heart surgery: a randomized trial.

OBJECTIVES: Intermittent cold blood cardioplegia is commonly used in children, whereas intermittent warm blood cardioplegia is widely used in adults. We aimed to compare clinical and biochemical outcomes with these 2 methods. METHODS: A single-centre, randomized controlled trial was conducted to compare the effectiveness of warm (≥34°C) versus cold (4-6°C) antegrade cardioplegia in children. The primary outcome was cardiac troponin T over the 1st 48 postoperative hours. Intensive care teams were blinded to group allocation. Outcomes were compared by intention-to-treat using linear mixed-effects, logistic or Cox regression. RESULTS: 97 participants with median age of 1.2 years were randomized (49 to warm, 48 to cold cardioplegia); 59 participants (61%) had a risk-adjusted congenital heart surgery score of 3 or above. There were no deaths and 92 participants were followed to 3-months. Troponin release was similar in both groups [geometric mean ratio 1.07; 95% confidence interval (CI) 0.79-1.44; P = 0.66], as were other cardiac function measures (echocardiography, arterial and venous blood gases, vasoactive-inotrope score, arrhythmias). Intensive care stay was on average 14.6 h longer in the warm group (hazard ratio 0.52; 95% CI 0.34-0.79; P = 0.003), with a trend towards longer overall hospital stays (hazard ratio 0.66; 95% CI 0.43-1.02; P = 0.060) compared with the cold group. This could be related to more unplanned reoperations on bypass in the warm group compared to cold group (3 vs 1). CONCLUSIONS: Warm blood cardioplegia is a safe and reproducible technique but does not provide superior myocardial protection in paediatric heart surgery.

Effective handovers on escalation of care for the deteriorating patient.

Evidence suggests that improvements in clinical practice are required to ensure that deteriorating patients are rapidly identified and assessed in a systematic manner. The important step of escalating care involves a detailed handover to the most appropriate colleague so that interventions can be put in place to reverse or optimise the patient's condition. However, multiple issues can hinder this handover process, including a lack of confidence among nurses and suboptimal team dynamics or cultures. Using structured communication tools such as situation, background, assessment, recommendation (SBAR) can assist nurses in delivering a handover that results in the desired outcome. This article explains the steps involved in identifying, assessing and escalating the care of deteriorating patients, and describes the components of an effective handover.

Critical effects and scaling at meniscus osculation transitions.

We propose a simple scaling theory describing critical effects at rounded meniscus osculation transitions which occur when the Laplace radius of a condensed macroscopic drop of liquid coincides with the local radius of curvature R_{w} in a confining parabolic geometry. We argue that the exponent ß_{osc} characterizing the scale of the interfacial height ℓ_{0}∝R_{w}^{ß_{osc}} at osculation, for large R_{w}, falls into two regimes representing fluctuation-dominated and mean-field-like behavior, respectively. These two regimes are separated by an upper critical dimension, which is determined here explicitly and depends on the range of the intermolecular forces. In the fluctuation-dominated regime, representing the universality class of systems with short-range forces, the exponent is related to the value of the interfacial wandering exponent ζ by ß_{osc}=3ζ/(4-ζ). In contrast, in the mean-field regime, which was not previously identified and which occurs for systems with longer-range forces (and higher dimensions), the exponent ß_{osc} takes the same value as the exponent ß_{s}^{co} for complete wetting, which is determined directly by the intermolecular forces. The prediction ß_{osc}=3/7 in d=2 for systems with short-range forces (corresponding to ζ=1/2) is confirmed using an interfacial Hamiltonian model which determines the exact scaling form for the decay of the interfacial height probability distribution function. A numerical study in d=3, based on a microscopic model density-functional theory, determines that ß_{osc}≈ß_{s}^{co}≈0.326 close to the predicted value of 1/3 appropriate to the mean-field regime for dispersion forces.

A Segmental Approach from Molecular Profiling to Medical Imaging to Study Bicuspid Aortic Valve Aortopathy.

Bicuspid aortic valve (BAV) patients develop ascending aortic (AAo) dilation. The pathogenesis of BAV aortopathy (genetic vs. haemodynamic) remains unclear. This study aims to identify regional changes around the AAo wall in BAV patients with aortopathy, integrating molecular data and clinical imaging. BAV patients with aortopathy (n = 15) were prospectively recruited to surgically collect aortic tissue and measure molecular markers across the AAo circumference. Dilated (anterior/right) vs. non-dilated (posterior/left) circumferential segments were profiled for whole-genomic microRNAs (next-generation RNA sequencing, miRCURY LNA PCR), protein content (tandem mass spectrometry), and elastin fragmentation and degeneration (histomorphometric analysis). Integrated bioinformatic analyses of RNA sequencing and proteomic datasets identified five microRNAs (miR-128-3p, miR-210-3p, miR-150-5p, miR-199b-5p, and miR-21-5p) differentially expressed across the AAo circumference. Among them, three miRNAs (miR-128-3p, miR-150-5p, and miR-199b-5p) were predicted to have an effect on eight common target genes, whose expression was dysregulated, according to proteomic analyses, and involved in the vascular-endothelial growth-factor signalling, Hippo signalling, and arachidonic acid pathways. Decreased elastic fibre levels and elastic layer thickness were observed in the dilated segments. Additionally, in a subset of patients n = 6/15, a four-dimensional cardiac magnetic resonance (CMR) scan was performed. Interestingly, an increase in wall shear stress (WSS) was observed at the anterior/right wall segments, concomitantly with the differentially expressed miRNAs and decreased elastic fibres. This study identified new miRNAs involved in the BAV aortic wall and revealed the concomitant expressional dysregulation of miRNAs, proteins, and elastic fibres on the anterior/right wall in dilated BAV patients, corresponding to regions of elevated WSS.

Intermittent attractive interactions lead to microphase separation in nonmotile active matter.

Nonmotile active matter exhibits a wide range of nonequilibrium collective phenomena yet examples are crucially lacking in the literature. We present a microscopic model inspired by the bacteria Neisseria meningitidis in which diffusive agents feel intermittent attractive forces. Through a formal coarse-graining procedure, we show that this truly scalar model of active matter exhibits the time-reversal-symmetry breaking terms defining the Active Model B+ class. In particular, we confirm the presence of microphase separation by solving the kinetic equations numerically. We show that the switching rate controlling the interactions provides a regulation mechanism tuning the typical cluster size, e.g., in populations of bacteria interacting via type IV pili.

Meniscus osculation and adsorption on geometrically structured walls.

We study the adsorption of simple fluids at smoothly structured, completely wet walls and show that a meniscus osculation transition occurs when the Laplace and geometrical radii of curvature of locally parabolic regions coincide. Macroscopically, the osculation transition is of fractional, 7/2, order and separates regimes in which the adsorption is microscopic, containing only a thin wetting layer, and mesoscopic, in which a meniscus exists. We develop a scaling theory for the rounding of the transition due to thin wetting layers and derive critical exponent relations that determine how the interfacial height scales with the geometrical radius of curvature. Connection with the general geometric construction proposed by Rascón and Parry is made. Our predictions are supported by a microscopic model density functional theory for drying at a sinusoidally shaped hard wall where we confirm the order of the transition and also an exact sum rule for the generalized contact theorem due to Upton. We show that as bulk coexistence is approached the adsorption isotherm separates into three regimes: A preosculation regime where it is microscopic, containing only a thin wetting layer; a mesoscopic regime, in which a meniscus sits within the troughs; and finally another microscopic regime where the liquid-gas interface unbinds from the crests of the substrate.

Casimir Contribution to the Interfacial Hamiltonian for 3D Wetting.

Previous treatments of three-dimensional (3D) short-ranged wetting transitions have missed an entropic or low-temperature Casimir contribution to the binding potential describing the interaction between the unbinding interface and wall. This we determine by exactly deriving the interfacial model for 3D wetting from a more microscopic Landau-Ginzburg-Wilson Hamiltonian. The Casimir term changes the interpretation of fluctuation effects occurring at wetting transitions so that, for example, mean-field predictions are no longer obtained when interfacial fluctuations are ignored. While the Casimir contribution does not alter the surface phase diagram, it significantly increases the adsorption near a first-order wetting transition and changes completely the predicted critical singularities of tricritical wetting, including the nonuniversality occurring in 3D arising from interfacial fluctuations. Using the numerical renormalization group, we show that, for critical wetting, the asymptotic regime is extremely narrow with the growth of the parallel correlation length characterized by an effective exponent in quantitative agreement with Ising model simulations, resolving a long-standing controversy.

Initial results from an enhanced recovery program for pediatric cardiac surgical patients.

BACKGROUND: Over recent years, a number of enhanced recovery programs have appeared in first, adult colorectal surgery, and subsequently many other adult surgical specialties. Increasing interest in this approach to perioperative management in children culminated in the recent development of the first enhanced recovery pathway for pediatric intestinal surgery, endorsed by Enhanced Recovery after Surgery Society (ERAS®). In parallel, there has been increasing interest in the refinement of perioperative management of selected pediatric cardiac surgical patients, invariably referred to as "fast track" management. Initiatives have largely focused on duration of postoperative ventilation rather than on a much wider range of perioperative interventions to optimize recovery and ensure timely discharge after surgery. In our institution, a "Level 1" pediatric cardiac surgical center, we assembled a multidisciplinary team to design a comprehensive enhanced recovery pathway, based on ERAS® methodology, for selected cardiac surgical patients. After a lengthy period of planning, staff education, and preparation, we implemented the pathway at the end of November 2019. METHODS: We conducted a prospective audit of the perioperative management and outcomes of the first 88 patients managed according to this enhanced recovery pathway over a 25-month period in our institution. RESULTS: The mean age of the patients was 5.8 years (range 0.5-17.9), and the mean weight was 22.4 kg (range 6.6-57.2). Sixty-eight of the 88 patients were cardiopulmonary bypass cases. A total of 54% of patients received all four defined intraoperative anesthetic interventions (intravenous paracetamol, non-steroidal anti-inflammatory drug, antiemetic if aged more than 4 years, and use of a local anesthetic technique). A total of 89% of patients met the target extubation time of 6 h after administration of protamine. Median postoperative intensive care unit length of stay was 23.5 h (range 15.2-89.5). When compared to a historic control group, this represented a 22% reduction in median intensive care unit stay, although the total hospital length of stay remained unchanged. A total of 83% of patients met the target hospital discharge target of the fifth postoperative day. CONCLUSIONS: These preliminary results suggest that enhanced recovery pathway implementation for selected pediatric cardiac surgical patients is feasible, with acceptable outcomes. They suggest areas for further development and the potential for wider implementation.

MRI features of canine hemangiosarcoma affecting the central nervous system.

Hemangiosarcoma is the most common metastatic tumor involving the brain in dogs but detailed published descriptions of the magnetic resonance imaging (MRI) features are lacking. The objective of this multi-center, retrospective case series study was to describe MRI characteristics of canine hemangiosarcoma affecting the central nervous system (CNS). Medical records of seven referral institutions were retrospectively reviewed. Dogs were included if they had a histopathologically confirmed diagnosis of hemangiosarcoma affecting the CNS and undergone an MRI of the brain and/or vertebral column. Lesions were independently evaluated by two observers. Twenty dogs met the inclusion criteria and one dog had both intracranial and intramedullary hemangiosarcoma. Consistent MRI features included heterogeneous (17/21) lesions in all sequences with mainly mixed signal intensity (12/21), presence of susceptibility artifact on T2*w (15/16), associated moderate to severe perilesional edema (21/21), and moderate to strong (20/21) heterogeneous (14/21) or ring-like (6/21) contrast enhancement. Intracranial hemangiosarcoma was frequently multiple and intra-axial, affecting consistently the telencephalon and no differences in MRI features were found between primary and metastatic hemangiosarcoma. This is the first MRI description of primary intracranial hemangiosarcoma and primary intracranial epithelioid hemangiosarcoma. Vertebral hemangiosarcomas were segmental poorly marginated polyostotic and highly aggressive lesions invading the thoracic vertebral canal and paraspinal tissues. Epidural hemangiosarcomas were single and well-marginated lesions in the thoracolumbar and/or lumbar region. Intramedullary hemangiosarcomas were cervical, metastatic in origin, and frequently (3/4) accompanied by intracranial lesions. These described MRI features will aid early identification of hemangiosarcoma guiding subsequent diagnostics and therapeutics.

Capillary condensation and depinning transitions in open slits.

We study the low-temperature phase equilibria of a fluid confined in an open capillary slit formed by two parallel walls separated by a distance L which are in contact with a reservoir of gas. The top wall of the capillary is of finite length H while the bottom wall is considered of macroscopic extent. This system shows rich phase equilibria arising from the competition between two different types of capillary condensation, corner filling, and meniscus depinning transitions depending on the value of the aspect ratio a=L/H and divides into three regimes: For long capillaries, with a<2/π, the condensation is of type I involving menisci which are pinned at the top edges at the ends of the capillary. For intermediate capillaries, with 2/π1, condensation is always of type II. In all regimes, capillary condensation is completely suppressed for sufficiently large contact angles which is determined explicitly. For long and intermediate capillaries, we show that there is an additional continuous phase transition in the condensed liquid-like phase, associated with the depinning of each meniscus as they round the upper open edges of the slit. Meniscus depinning is third-order for complete wetting and second-order for partial wetting. Detailed scaling theories are developed for these transitions and phase boundaries which connect with the theories of wedge (corner) filling and wetting encompassing interfacial fluctuation effects and the direct influence of intermolecular forces. We test several of our predictions using a fully microscopic density functional theory which allows us to study the two types of capillary condensation and its suppression at the molecular level for different aspect ratios and contact angles.

Edge Contact Angle, Capillary Condensation, and Meniscus Depinning.

We study the phase equilibria of a fluid confined in an open capillary slit formed when a wall of finite length H is brought a distance L away from a second macroscopic surface. This system shows rich phase equilibria arising from the competition between two different types of capillary condensation, corner filling and meniscus depinning transitions depending on the value of the aspect ratio a=L/H. For long capillaries, with a<2/π, the condensation is of type I involving menisci which are pinned at the top edges at the ends of the capillary characterized by an edge contact angle. For intermediate capillaries, with 2/π1, condensation is always of type II. In all regimes, capillary condensation is completely suppressed for sufficiently large contact angles. We show that there is an additional continuous phase transition in the condensed liquidlike phase, associated with the depinning of each meniscus as they round the upper open edges of the slit. Finite-size scaling predictions are developed for these transitions and phase boundaries which connect with the fluctuation theories of wetting and filling transitions. We test several of our predictions using a fully microscopic density functional theory which allows us to study the two types of capillary condensation and its suppression at the molecular level.