Mitral Valve Surgery for Mitral Regurgitation Results in Reduced Left Ventricular Ejection Fraction in Barlow's Disease as Compared with Fibro-Elastic Deficiency.

Surgical correction of severe mitral regurgitation (MR) can reverse left ventricular (LV) remodeling in patients with mitral valve prolapse (MVP). However, whether this process is similar to the case in Barlow's Disease (BD) and Fibro-elastic Deficiency (FED) is currently unknown. The aim of this study is to evaluate post-operative LV reverse remodeling and function in patients with BD versus FED. In this study, 100 MVP patients (BD = 37 and FED = 63) with severe MR who underwent mitral valve surgery at three Belgian centers were retrospectively included. Transthoracic echocardiography was used to assess MR severity, LV volumes and function before surgery and 6 months thereafter. Baseline MR severity, LV ejection fraction (LVEF), indexed LV end-diastolic (LVEDVi) and end-systolic volumes (LVESVi) were not different between the groups. After a median follow-up of 278 days, there was a similar decrease in LVEDVi, but a trend towards a smaller decrease in LVESVi in BD compared to FED (-3.0 ± 11.2 mL/m2 vs. -5.3 ± 9.0 mL/m2; p = 0.154). This resulted in a significantly larger decrease in LVEF in BD (-8.3 ± 9.6%) versus FED (-3.9 ± 6.9%) after adjusting for baseline LVEF (p < 0.001) and type of surgical intervention (p = 0.01). These findings suggest that LV (reverse) remodeling in BD could be affected by other mechanisms beyond volume overload, potentially involving concomitant cardiomyopathy.

Assessing Pleiotropic Effects of a Mixed-Mode Perpetrator Drug, Rifampicin, by Multiple Endogenous Biomarkers in Dogs.

Rifampicin (RIF) is a mixed-mode perpetrator that produces pleiotropic effects on liver cytochrome P450 enzymes and drug transporters. To assess the complex drug-drug interaction liabilities of RIF in vivo, a known probe substrate, midazolam (MDZ), along with multiple endogenous biomarkers were simultaneously monitored in beagle dogs before and after a 7-day treatment period by RIF at 20 mg/kg per day. Confirmed by the reduced MDZ plasma exposure and elevated 4ß-hydroxycholesterol (4ß-HC, biomarker of CYP3A activities) level, CYP3A was significantly induced after repeated RIF doses, and such induction persisted for 3 days after cessation of the RIF administration. On the other hand, increased plasma levels of coproporphyrin (CP)-I and III [biomarkers of organic anion transporting polypeptides 1b (Oatp1b) activities] were observed after the first dose of RIF. Plasma CPs started to decline as RIF exposure decreased, and they returned to baseline 3 days after cessation of the RIF administration. The data suggested the acute (inhibitory) and chronic (inductive) effects of RIF on Oatp1b and CYP3A enzymes, respectively, and a 3-day washout period is deemed adequate to remove superimposed Oatp1b inhibition from CYP3A induction. In addition, apparent self-induction of RIF was observed as its terminal half-life was significantly altered after multiple doses. Overall, our investigation illustrated the need for appropriate timing of modulator dosing to differentiate between transporter inhibition and enzyme induction. As further indicated by the CP data, induction of Oatp1b activities was not likely after repeated RIF administration. SIGNIFICANCE STATEMENT: This investigation demonstrated the utility of endogenous biomarkers towards complex drug-drug interactions by rifampicin (RIF) and successfully determined the optimal timing to differentiate between transporter inhibition and enzyme induction. Based on experimental evidence, Oatp1b induction following repeated RIF administration was unlikely, and apparent self-induction of RIF elimination was observed.

Charge Density Overcomes Steric Hindrance of Ferrocene Surfactant in Switchable Oil-in-Dispersion Emulsions.

A ferrocene surfactant can be switched between single and double head form (FcN+ C12 /Fc+ N+ C12 ) triggered by redox reaction. FcN+ C12 can neither stabilize an O/W emulsion alone nor an oil-in-dispersion emulsion in combination with alumina nanoparticles due to the steric hindrance of the ferrocene group. However, such steric hindrance can be overcome by increasing the charge density in Fc+ N+ C12 , so that oil-in-dispersion emulsions can be co-stabilized by Fc+ N+ C12 and alumina nanoparticles at very low concentrations (1×10-7  M (≈50 ppb) and 0.001 wt %, respectively). Not only can reversible formation/destabilization of oil-in-dispersion emulsions be achieved by redox reaction, but also reversible transformation between oil-in-dispersion emulsions and Pickering emulsions can be obtained through reversing the charge of alumina particles by adjusting the pH. The results provide a new protocol for the design of surfactants for stabilization of smart oil-in-dispersion emulsions.

Three-dimensional echocardiography of the athlete's heart: a comparison with cardiac magnetic resonance imaging.

Three-dimensional echocardiography (3DE) is the most accurate cardiac ultrasound technique to assess cardiac structure. 3DE has shown close correlation with cardiac magnetic resonance imaging (CMR) in various populations. There is limited data on the accuracy of 3DE in athletes and its value in detecting alterations during follow-up. Indexed left and right ventricular end-diastolic volume (LVEDVi, RVEDVi), end-systolic volume, ejection fraction (LVEF, RVEF) and left ventricular mass (LVMi) were assessed by 3DE and CMR in two-hundred and one competitive endurance athletes (79% male) from the Pro@Heart trial. Sixty-four athletes were assessed at 2 year follow-up. Linear regression and Bland-Altman analyses compared 3DE and CMR at baseline and follow-up. Interquartile analysis evaluated the agreement as cardiac volumes and mass increase. 3DE showed strong correlation with CMR (LVEDVi r = 0.91, LVEF r = 0.85, LVMi r = 0.84, RVEDVi r = 0.84, RVEF r = 0.86 p < 0.001). At follow up, the percentage change by 3DE and CMR were similar (∆LVEDVi r = 0.96 bias - 0.3%, ∆LVEF r = 0.94, bias 0.7%, ∆LVMi r = 0.94 bias 0.8%, ∆RVESVi r = 0.93, bias 1.2%, ∆RVEF r = 0.87 bias 0.4%). 3DE underestimated volumes (LVEDVi bias - 18.5 mL/m2, RVEDVi bias - 25.5 mL/m2) and the degree of underestimation increased with larger dimensions (Q1vsQ4 LVEDVi relative bias - 14.5 versus - 17.4%, p = 0.016; Q1vsQ4 RVEDVi relative bias - 17 versus - 21.9%, p = 0.005). Measurements of cardiac volumes, mass and function by 3DE correlate well with CMR and 3DE accurately detects changes over time. 3DE underestimates volumes and the relative bias increases with larger cardiac size.

Fabrication of Stable Oleofoams with Sorbitan Ester Surfactants.

Sorbitan esters have been extensively used as surfactants to stabilize emulsions in many fields. However, the preparation of an oleofoam with sorbitan ester alone has not been reported. Here, we apply a novel protocol to fabricate stable oleofoams of high air volume fraction from mixtures of vegetable oil and sorbitan ester. To incorporate more air bubbles into the oil matrix, aeration is first carried out in the one-phase region at high temperatures, during which the highest over-run can reach 280%. Due to foam instability at high temperatures, the foam is then submitted to rapid cooling, followed by storage at low temperatures. For high-melting sorbitan monostearate, the resulting foams containing many crystal-encased air bubbles are ultrastable to drainage, coarsening, and coalescence for several months. On the contrary, the cooled foams with low-melting sorbitan monooleate go through a gradual decay lasting for more than 1 month. We highlight the importance of hydrogen bond formation between surfactant and oil in enhancing foam stability. The generic nature of the above findings is demonstrated by preparing oil foams with various vegetable oils and sorbitan monooleate.

Serum autoantibody reactivity in bullous pemphigoid is associated with neuropsychiatric disorders and the use of antidiabetics and antipsychotics: a large, prospective cohort study.

BACKGROUND: Bullous pemphigoid (BP), the by far most frequent autoimmune blistering skin disease (AIBD), is immunopathologically characterized by autoantibodies against the two hemidesmosomal proteins BP180 (collagen type XVII) and BP230 (BPAG1 or dystonin). Several comorbidities and potentially disease-inducing medication have been described in BP, yet a systematic analysis of these clinically relevant findings and autoantibody reactivities has not been performed. OBJECTIVE: To determine associations of autoantibody reactivities with comorbidities and concomitant medication. METHODS: In this prospective multicenter study, 499 patients diagnosed with BP in 16 European referral centers were included. The relation between anti-BP180 NC16A and anti-BP230 IgG ELISA values at the time of diagnosis as well as comorbidities and concomitant medication collected by a standardized form were analysed. RESULTS: An association between higher serum anti-BP180 reactivity and neuropsychiatric but not atopic and metabolic disorders was observed as well as with the use of insulin or antipsychotics but not with dipeptidyl peptidase-4 (DPP4) inhibitors, inhibitors of platelet aggregation and L-thyroxine. The use of DPP4 inhibitors was associated with less anti-BP180 and anti-BP230 reactivity compared with BP patients without these drugs. This finding was even more pronounced when compared with diabetic BP patients without DPP4 inhibitors. Associations between anti-BP180 and anti-BP230 reactivities were also found in patients using insulin and antipsychotics, respectively, compared with patients without this medication, but not for the use of inhibitors of platelet aggregation, and L-thyroxine. CONCLUSION: Taken together, these data imply a relation between autoantibody reactivities at the time of diagnosis and both neuropsychiatric comorbidities as well as distinct concomitant medication suggesting a link between the pathological immune mechanisms and clinical conditions that precede the clinically overt AIBD.

Individual and Joint Effects of Influenza-Like Illness and Vaccinations on Stroke in the Young: A Case-Control Study.

BACKGROUND: Influenza-like illness (ILI) is an acute trigger for stroke, although joint effects of vaccinations and ILI have not yet been explored. METHODS: Data for our case-control study was obtained from MarketScan Commercial Claims and Encounters between 2008 and 2014. Patients 18 to 65 years old who experienced a stroke were matched on age and admission date to a control, defined as patients with head trauma or ankle sprain at an inpatient or emergency department visit. Exposures were ILI in the prior 30 days, and any type of vaccination during the year prior. Our outcome was ischemic and intracerebral hemorrhagic strokes identified using International Classification of Diseases, Ninth Revision (ICD-9) codes. Logistic regression models estimated adjusted odds ratios (aORs) controlling for preventive care visits, diabetes, valvular heart disease, smoking, alcohol abuse, obesity, and hypertension. RESULTS: We identified and matched 24 103 cases 18 to 44 years old and 141 811 45 to 65 years old. Those aged 18 to 44 years had increased stroke risk 30 days after ILI (aOR, 1.68 [95% CI, 1.51-1.86]) and reduced risk with any vaccination in the year prior (aOR, 0.92 [95% CI, 0.87-0.99]). Joint effects indicate that ILI was associated with increased stroke risk among those with (aOR, 1.41 [95% CI, 1.08-1.85]) and without (aOR, 1.73 [95% CI, 1.55-1.94]) vaccinations in the prior year (Pinteraction=0.16). Among those aged 45 to 65 years, adjusted analyses indicate increased stroke risk for those with ILI (aOR, 1.32 [95% CI, 1.26-1.38]), although there was no effect of vaccinations (aOR, 1.00 [95% CI, 0.97-1.02]). Joint effects indicate that ILI was not associated with stroke among those with any vaccination (aOR, 1.07 [95% CI, 0.96-1.18]) but was associated with increased risk among those without vaccinations ([aOR, 1.39 [95% CI, 1.32-1.47]; Pinteraction<0.001). CONCLUSIONS: ILI was associated with increased stroke risk in the young and middle-aged, while vaccinations of any type were associated with decreased risk among the young. Joint effects of ILI and vaccinations indicate vaccinations can reduce the effect of ILI on stroke.

Oil-in-Water emulsions stabilized by alumina nanoparticles with organic electrolytes: Fate of particles.

HYPOTHESIS: Oil-in-dispersion emulsions can be stabilized by like charged particles and surfactant. Surfactant adsorbs at the oil-water interface to reduce the interfacial tension and endow the interface with charge, while particles remain dispersed in the aqueous phase to provide electrostatic repulsion between droplets and particles. Can weakly surface-active organic electrolytes adsorb at the oil-water interface and behave like surfactants in stabilizing oil-in-dispersion emulsions with like charged particles? EXPERIMENTS: Symmetrical organic electrolytes, tetraalkylammonium bromides (R4NBr), with either no or very low interfacial activity endowing oil droplets with charge were combined with alumina nanoparticles to stabilize emulsions. The effect of R chain length (varying from methyl to butyl) on the type and stability of emulsions was investigated. FINDINGS: Mixtures of high concentrations of short chain R4NBr salts (R = methyl or ethyl) and alumina particles stabilise oil-in-water Pickering emulsions, whereas longer chain (R = propyl or butyl) analogues stabilize oil-in-dispersion emulsions assisted by alumina particles. Tetrapropylammonium and tetrabutylammonium cations adsorb at the oil-water interface reducing the interfacial tension and endowing the interface with charge. The stability of the oil-in-dispersion emulsions is dominated by the electrostatic repulsion between the droplets and between droplets and particles in the continuous aqueous phase.

Association of NOTCH3 Variant Position With Stroke Onset and Other Clinical Features Among Patients With CADASIL.

BACKGROUND AND OBJECTIVES: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is caused by a cysteine-altering mutation in one of the thirty-four epidermal growth factor-like repeat (EGFR) domains of the NOTCH3 protein. CADASIL has a variable phenotypic presentation and NOTCH3 mutations in EGFRs 1-6 have been found correlated with greater disease severity. We examined clinical and radiological features and performed bioinformatic annotation of mutations in a large CADASIL cohort to further understand these associations. METHODS: We examined the association of NOTCH3 variant position on stroke onset and other clinical features among patients with CADASIL from the United Kingdom. We also explored how in-silico predicted protein aggregation differed by variant position and the extent to which this affected stroke risk. RESULTS: We identified 76 different cysteine-altering NOTCH3 variants in our cohort of 485 patients (mean age: 50.1 years; % male: 57.5). After controlling for cardiovascular risk factors, variants in EGFRs 1-6 were associated with earlier onset of stroke (hazard ratio [HR]: 2.05, 95% CI: 1.43-2.94) and encephalopathy (HR: 2.70, 95% CI: 1.15-6.37), than variants in EGFRs 7-34. Although the risk of stroke was higher in the patients with predicted protein aggregation (HR: 1.50, 95% CI: 1.05-2.14), this association was no longer significant after controlling for variant site. Further analysis suggested lower stroke risk was observed for variants in EGFRs 10-17 compared to variants in the other EGFR domains. DISCUSSION: NOTCH3 variant position is a predictor of stroke and encephalopathy in CADASIL independent of cardiovascular risk factors. Lower stroke risk was found for variants in EGFRs 10-17. Molecular factors that influence CADASIL disease severity remain to be determined.

Stabilisation of oleofoams by lauric acid and its glycerol esters.

Four types of pure lipid, namely lauric acid (LA), glycerol monolaurate (MAG), diglycerol laurate (DAG) and triglyceride laurate (TAG) were used to prepare oleofoams. The relationship between crystal profiles and their performance in oleofoams was established. DAG formed small needle-like crystals while MAG formed large flake-like crystals in oleogels, and crystal shells around air bubbles were observed in LA-, MAG- and DAG-based oleofoams. LA and DAG displayed higher over-run whereas DAG-stabilised foam possessed smaller bubbles and higher physical stability due to the presence of small ß and ß' crystals. Upon heating, DAG and TAG-based foams showed varying extents of oil drainage indicating the crystals were distributed in a different manner. Therefore, DAG was shown to be an excellent gelator in the fabrication of ultra-stable oleofoams. This work extends the lipid varieties with nutritional features and allows a better understanding on the stabilization mechanisms of lauric acid lipids in oleofoams.

Water-in-oil high internal phase Pickering emulsions formed by spontaneous interfacial hydrolysis of monomer oil.

HYPOTHESIS: Alcohols can strongly reduce the interfacial tension between immiscible liquids, thus facilitating the formation of emulsions. By combining non-surface-active hydrophobic particles with medium-chain alcohols, stable water-in-oil (w/o) high internal phase Pickering emulsions (HIPPEs) can be easily prepared without high-energy emulsification methods. EXPERIMENTS: The emulsions containing acrylate monomer as the oil phase were prepared at different pH values in the presence of hydrophobic silica particles. Further, by replacing monomer oil with organic solvents (e.g., toluene) and a certain concentration of alcohol, the promoted particle adsorption at the oil-water interface has been systematically investigated. The morphology and interfacial structure of HIPPEs were visualized by confocal laser scanning microscopy (CLSM). FINDING: At high pH, stable water-in-acrylate monomer HIPPEs can be formed using commercial fumed silica nanoparticles alone with simple stirring or vortexing. The hydrolysis of the acrylate group at high pH can generate alcohols in situ which adsorb at the oil-water interface to reduce the interfacial tension and promote particle adsorption to hinder droplet coalescence. The novel strategy for forming stable and processable HIPPEs can be universally applied to different hydrophobic silica particles with the help of various alcohols as the co-stabilizer, which provides a flexible approach for the fabrication of lightweight, closed-cell solid foams for a range of applications.

Clinical profile and outcome of recurrent infective endocarditis.

AIMS: Purpose of this study is to compare the clinical course and outcome of patients with recurrent versus first-episode infective endocarditis (IE). METHODS: Patients with recurrent and first-episode IE enrolled in the EUROpean ENDOcarditis (EURO-ENDO) registry including 156 centres were identified and compared using propensity score matching. Recurrent IE was classified as relapse when IE occurred ≤6 months after a previous episode or reinfection when IE occurred >6 months after the prior episode. RESULTS: 3106 patients were enrolled: 2839 (91.4%) patients with first-episode IE (mean age 59.4 (±18.1); 68.3% male) and 267 (8.6%) patients with recurrent IE (mean age 58.1 (±17.7); 74.9% male). Among patients with recurrent IE, 13.2% were intravenous drug users (IVDUs), 66.4% had a repaired or replaced valve with the tricuspid valve being more frequently involved compared with patients with first-episode IE (20.3% vs 14.1%; p=0.012). In patients with a first episode of IE, the aortic valve was more frequently involved (45.6% vs 39.5%; p=0.061). Recurrent relapse and reinfection were 20.6% and 79.4%, respectively. Staphylococcus aureus was the microorganism most frequently observed in both groups (p=0.207). There were no differences in in-hospital and post-hospitalisation mortality between recurrent and first-episode IE. In patients with recurrent IE, in-hospital mortality was higher in IVDU patients. Independent predictors of poorer in-hospital and 1-year outcome, including the occurrence of cardiogenic and septic shock, valvular disease severity and failure to undertake surgery when indicated, were similar for recurrent and first-episode IE. CONCLUSIONS: In-hospital and 1-year mortality was similar in patients with recurrent and first-episode IE who shared similar predictors of poor outcome.

Comparing Revision Total Knee Arthroplasty Stems at a High-Volume Revision Center.

Introduction: Hybrid fixation and fully cemented fixation are commonly used in revision total knee arthroplasty (rTKA). These two techniques are typically done based on surgeon preference and one has not demonstrated superiority over the other. The purpose of this study was to examine if there was a difference in survivorship between the two different techniques. Methods: A retrospective cohort study of all consecutive patients undergoing rTKA (CPT 27487) from January 1, 2011 to January 1, 2018 at a single academic center was performed. Patients were divided into cemented and hybrid rTKA groups with comparison of patient demographic, clinical and radiological outcomes, reoperation, change in post-operative hemoglobin (HgB), and length of stay (LOS). Results: A total of 133 rTKA for 122 patients were identified: 30.1% in the cemented and 69.9% in the hybrid groups. There was no significant difference in age (p = 0.491), sex (p = 0.250), laterality (p = 0.421), or body mass index (BMI) (p = 0.609) between the two groups. Mean LOS (hybrid 4.13 days, cemented 3.65 days; p = 0.356) and change in Hgb (hybrid 2.95 mg/dL, cemented 2.62mg/dL; p = 0.181) were not statistically different between the groups. Mean follow up for the hybrid (25.4 months, range 2-114 months) and cemented (24.6 months, range 3-75.5 months) rTKA was not statistically significant (p = 0.825). Overall survival rates were 80.9% in the hybrid and 84.6% in the cemented groups (p = 0.642). Conclusions: Hybrid and fully cemented rTKA techniques have similar survival rates at a minimum followup of 2 years. Additionally, in our cohort, age, gender, and BMI were not associated with failure in either group. Furthermore, we did not observe differences in LOS or change in hemoglobin suggesting early postoperative complications may not differ between cemented and hybrid stemmed groups. Continued long-term research is required for defining the best rTKA technique.

Buckling versus Crystal Expulsion Controlled by Deformation Rate of Particle-Coated Air Bubbles in Oil.

Oil foams stabilized by crystallizing agents exhibit outstanding stability and show promise for applications in consumer products. The stability and mechanics imparted by the interfacial layer of crystals underpin product shelf life, as well as optimal processing conditions and performance in applications. Shelf life is affected by the stability against bubble dissolution over a long time scale, which leads to slow compression of the interfacial layer. In processing flow conditions, the imposed deformation is characterized by much shorter time scales. In practical situations, the crystal layer is therefore subjected to deformation on extremely different time scales. Despite its importance, our understanding of the behavior of such interfacial layers at different time scales remains limited. To address this gap, here we investigate the dynamics of single, crystal-coated bubbles isolated from an oleofoam, at two extreme time scales: the diffusion-limited time scale characteristic of bubble dissolution, ∼104 s, and a fast time scale characteristic of processing flow conditions, ∼10-3 s. In our experiments, slow deformation is obtained by bubble dissolution, and fast deformation in controlled conditions with real-time imaging is obtained using ultrasound-induced bubble oscillations. The experiments reveal that the fate of the interfacial layer is dramatically affected by the dynamics of deformation: after complete bubble dissolution, a continuous solid layer remains; after fast, oscillatory deformation of the layer, small crystals are expelled from the layer. This observation shows promise toward developing stimuli-responsive systems, with sensitivity to deformation rate, in addition to the already known thermoresponsiveness and photoresponsiveness of oleofoams.

Correction: Spontaneous particle desorption and "Gorgon" drop formation from particle-armored oil drops upon cooling.

Correction for 'Spontaneous particle desorption and "Gorgon" drop formation from particle-armored oil drops upon cooling' by Diana Cholakova et al., Soft Matter, 2020, 16, 2480-2496, DOI: 10.1039/C9SM02354B.

Key Metabolic Enzymes Involved in Remdesivir Activation in Human Lung Cells.

Remdesivir (RDV; GS-5734, Veklury), the first FDA-approved antiviral to treat COVID-19, is a single-diastereomer monophosphoramidate prodrug of an adenosine analogue. RDV is taken up in the target cells and metabolized in multiple steps to form the active nucleoside triphosphate (TP) (GS-443902), which, in turn, acts as a potent and selective inhibitor of multiple viral RNA polymerases. In this report, we profiled the key enzymes involved in the RDV metabolic pathway with multiple parallel approaches: (i) bioinformatic analysis of nucleoside/nucleotide metabolic enzyme mRNA expression using public human tissue and lung single-cell bulk mRNA sequence (RNA-seq) data sets, (ii) protein and mRNA quantification of enzymes in human lung tissue and primary lung cells, (iii) biochemical studies on the catalytic rate of key enzymes, (iv) effects of specific enzyme inhibitors on the GS-443902 formation, and (v) the effects of these inhibitors on RDV antiviral activity against SARS-CoV-2 in cell culture. Our data collectively demonstrated that carboxylesterase 1 (CES1) and cathepsin A (CatA) are enzymes involved in hydrolyzing RDV to its alanine intermediate MetX, which is further hydrolyzed to the monophosphate form by histidine triad nucleotide-binding protein 1 (HINT1). The monophosphate is then consecutively phosphorylated to diphosphate and triphosphate by cellular phosphotransferases. Our data support the hypothesis that the unique properties of RDV prodrug not only allow lung-specific accumulation critical for the treatment of respiratory viral infection such as COVID-19 but also enable efficient intracellular metabolism of RDV and its MetX to monophosphate and successive phosphorylation to form the active TP in disease-relevant cells.

Hip and Knee Bracing: Categorization, Treatment Algorithm, and Systematic Review.

Hip and knee braces or orthoses are often used to provide support after surgery and to prevent or reduce the severity of injuries. The braces are used for stabilization, immobilization, mechanical correction, and rehabilitation. Hip braces consist of stabilization and unloader variations, whereas knee braces are composed of knee sleeves and patellofemoral, prophylactic, unloader, and functional braces. Indications vary widely and depend on the type of brace. Hip braces can treat osteoarthritis to instability after total hip arthroplasty. Knee brace indications range from mild arthralgias to instability and osteoarthritis. Although braces are routinely used clinically, high-level evidence is sparse for their use. With this review, the different types and uses of hip and knee braces have been defined, and their indications exemplified in hopes of spurring future research.

Aqueous and Oil Foams Stabilized by Surfactant Crystals: New Concepts and Perspectives.

Surfactant crystals can stabilize liquid foams. The crystals are adsorbed at bubble surfaces, slowing down coarsening and coalescence. Excess crystals in the liquid channels between bubbles arrest drainage, leading to ultrastable foams. The melting of crystals upon raising the temperature allows thermoresponsive foams to be designed. In the case of oil foams, the stabilization by crystals received substantial renewed interest in the last 5 years due to their potential applications, particularly in the food industry. For aqueous foams, several reports exist on foams stabilized by crystals. However, these two kinds of liquid foams possess similarities in terms of stabilization mechanisms and the design of surfactant crystal systems. This field will certainly grow in the coming years, and it will contribute to the engineering of new soft materials not only for food but also for cosmetics, pharmaceuticals, and biomedical applications.

Particle-stabilized oil foams.

The area of oil foams although important industrially has received little academic attention until the last decade. The early work using molecular surfactants for stabilisation was limited and as such it is difficult to obtain general rules of thumb. Recently however, interest has grown in the area partly fuelled by the understanding gained in the general area of colloidal particles at fluid interfaces. We review the use of solid particles as foaming agents for oil foams in cases where particles (inorganic or polymer) are prepared ex situ and in cases where crystals of surfactant or fat are prepared in situ. There is considerable activity in the latter area which is particularly relevant to the food industry. Discussion of crude oil/lubricating oil foams is excluded from this review.

A novel strategy to fabricate stable oil foams with sucrose ester surfactant.

HYPOTHESIS: Can a mixture of sucrose ester surfactant in vegetable oil be aerated to yield stable oleofoams? Is foaming achievable from one-phase molecular solutions and/or two-phase crystal dispersions? Does cooling a foam after formation induce surfactant crystallisation and enhance foam stability? EXPERIMENTS: Concentrating on extra virgin olive oil, we first study the effect of aeration temperature and surfactant concentration on foamability and foam stability of mixtures cooled from a one-phase oil solution. Based on this, we introduce a strategy to increase foam stability by rapidly cooling foam prepared at high temperature which induces surfactant crystallisation in situ. Differential scanning calorimetry, X-ray diffraction, infra-red spectroscopy, surface tension and rheology are used to elucidate the mechanisms. FINDINGS: Unlike previous reports, both foamability and foam stability decrease upon decreasing the aeration temperature into the two-phase region containing surfactant crystals. At high temperature in the one-phase region, substantial foaming is achieved (over-run 170%) within minutes of whipping but foams ultimately collapse within a week. We show that surfactant molecules are surface-active at high temperature and that hydrogen bonds form between surfactant and oil molecules. Cooling these foams substantially increases foam stability due to both interfacial and bulk surfactant crystallisation. The generic nature of our findings is demonstrated for a range of vegetable oil foams with a maximum over-run of 330% and the absence of drainage, coalescence and disproportionation being achievable.