Origin of Anomalously Large Depletion Zones in Like-Charged Colloid-Polyelectrolyte Mixtures.

Depletion zones in polyelectrolyte solutions in contact with like-charged flat surfaces are investigated. Using a coupled self-consistent field and Debye-Hückel approach, an explicit expression for the thickness δ of the depletion layer is derived. It is found that δ∼δ_{n}+cκ^{-1}, where δ_{n} is the depletion thickness at a neutral surface, c is a function of the electrostatic characteristics of the system, and κ^{-1} is the Debye length. It is argued that the theory still holds beyond the mean-field approximation, which is confirmed by quantitative agreement between our theoretical results and experiments.

Correction: van Veelen et al. First-in-Human Drug-Eluting Balloon Treatment of Vulnerable Lipid-Rich Plaques: Rationale and Design of the DEBuT-LRP Study. J. Clin. Med. 2023, 12, 5807.

In the original publication [...].

First-in-Human Drug-Eluting Balloon Treatment of Vulnerable Lipid-Rich Plaques: Rationale and Design of the DEBuT-LRP Study.

Patients with non-obstructive lipid-rich plaques (LRPs) on combined intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) are at high risk for future events. Local pre-emptive percutaneous treatment of LRPs with a paclitaxel-eluting drug-coated balloon (PE-DCB) may be a novel therapeutic strategy to prevent future adverse coronary events without leaving behind permanent coronary implants. In this pilot study, we aim to investigate the safety and feasibility of pre-emptive treatment with a PE-DCB of non-culprit non-obstructive LRPs by evaluating the change in maximum lipid core burden in a 4 mm segment (maxLCBImm4) after 9 months of follow up. Therefore, patients with non-ST-segment elevation acute coronary syndrome underwent 3-vessel IVUS-NIRS after treatment of the culprit lesion to identify additional non-obstructive non-culprit LRPs, which were subsequently treated with PE-DCB sized 1:1 to the lumen. We enrolled 45 patients of whom 20 patients (44%) with a non-culprit LRP were treated with PE-DCB. After 9 months, repeat coronary angiography with IVUS-NIRS will be performed. The primary endpoint at 9 months is the change in maxLCBImm4 in PE-DCB-treated LRPs. Secondary endpoints include clinical adverse events and IVUS-derived parameters such as plaque burden and luminal area. Clinical follow-up will continue until 1 year after enrollment. In conclusion, this first-in-human study will investigate the safety and feasibility of targeted pre-emptive PE-DCB treatment of LRPs to promote stabilization of vulnerable coronary plaque at risk for developing future adverse events.

Osteogenesis and osteoclastogenesis on a chip: Engineering a self-assembling 3D coculture.

Healthy bone is maintained by the process of bone remodeling. An unbalance in this process can lead to pathologies such as osteoporosis which are often studied with animal models. However, data from animals have limited power in predicting the results that will be obtained in human clinical trials. In search for alternatives to animal models, human in vitro models are emerging as they address the principle of reduction, refinement, and replacement of animal experiments (3Rs). At the moment, no complete in vitro model for bone-remodeling exists. Microfluidic chips offer great possibilities, particularly because of the dynamic culture options, which are crucial for in vitro bone formation. In this study, a scaffold free, fully human, 3D microfluidic coculture model of bone remodeling is presented. A bone-on-a-chip coculture system was developed in which human mesenchymal stromal cells differentiated into the osteoblastic lineage and self-assembled into scaffold free bone-like tissues with the shape and dimensions of human trabeculae. Human monocytes were able to attach to these tissues and to fuse into multinucleated osteoclast-like cells, establishing the coculture. Computational modeling was used to determine the fluid flow induced shear stress and strain in the formed tissue. Furthermore, a set-up was developed allowing for long-term (35 days) on-chip cell culture with benefits including continuous fluid-flow, low bubble formation risk, easy culture medium exchange inside the incubator and live cell imaging options. This on-chip coculture is a crucial advance towards developing in vitro bone remodeling models to facilitate drug testing.

Single antiplatelet therapy directly after percutaneous coronary intervention in non-ST-segment elevation acute coronary syndrome patients: the OPTICA study.

BACKGROUND: Early P2Y12 inhibitor monotherapy has emerged as a promising alternative to 12 months of dual antiplatelet therapy following percutaneous coronary intervention (PCI). AIMS: In this single-arm pilot study, we evaluated the feasibility and safety of ticagrelor or prasugrel monotherapy directly following PCI in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). METHODS: Patients received a loading dose of ticagrelor or prasugrel before undergoing platelet function testing and subsequent PCI using new-generation drug-eluting stents. The stent result was adjudicated with optical coherence tomography in the first 35 patients. Ticagrelor or prasugrel monotherapy was continued for 12 months. The primary ischaemic endpoint was the composite of all-cause mortality, myocardial infarction, definite or probable stent thrombosis or stroke within 6 months. The primary bleeding endpoint was Bleeding Academic Research Consortium type 2, 3 or 5 bleeding within 6 months. RESULTS: From March 2021 to March 2022, 125 patients were enrolled, of whom 75 ultimately met all in- and exclusion criteria (mean age 64.5 years, 29.3% women). Overall, 70 out of 75 (93.3%) patients were treated with ticagrelor or prasugrel monotherapy directly following PCI. The primary ischaemic endpoint occurred in 3 (4.0%) patients within 6 months. No cases of stent thrombosis or spontaneous myocardial infarction occurred. The primary bleeding endpoint occurred in 7 (9.3%) patients within 6 months. CONCLUSIONS: This study provides first-in-human evidence that P2Y12 inhibitor monotherapy directly following PCI for NSTE-ACS is feasible, without any overt safety concerns, and highlights the need for randomised controlled trials comparing direct P2Y12 inhibitor monotherapy with the current standard of care.

Depletion interaction mediated by semiflexible polymers.

We present a simple mean-field theory to describe the polymer-mediated depletion attraction between colloidal particles that accounts for the polymer's chain stiffness. We find that for fixed polymer radius of gyration and volume fraction, the strength of this attraction increases with increasing chain stiffness in both dilute and semidilute concentration regimes. In contrast, the range of attraction monotonically decreases with chain stiffness in the dilute regime, while it attains a maximum in the semidilute regime. The obtained analytical expressions for the depletion interaction were compared with numerical self-consistent field lattice computations and shown to be in quantitative agreement. From the interaction potential between two spheres, we calculated the second osmotic virial coefficient B2, which appears to be a convex function of chain stiffness. A minimum of B2 as a function of chain stiffness was observed both in the numerical self-consistent field computations and the analytical theory. These findings help explain the general observation that semiflexible polymers are more effective depletants than flexible polymers and give insight into the phase behavior of mixtures containing spherical colloids and semiflexible polymers.

Transcatheter aortic valve implantation amid the COVID-19 pandemic: a nationwide analysis of the first COVID-19 wave in the Netherlands.

INTRODUCTION: The coronavirus disease 2019 (COVID-19) pandemic has put tremendous pressure on healthcare systems. Most transcatheter aortic valve implantation (TAVI) centres have adopted different triage systems and procedural strategies to serve highest-risk patients first and to minimise the burden on hospital logistics and personnel. We therefore assessed the impact of the COVID-19 pandemic on patient selection, type of anaesthesia and outcomes after TAVI. METHODS: We used data from the Netherlands Heart Registration to examine all patients who underwent TAVI between March 2020 and July 2020 (COVID cohort), and between March 2019 and July 2019 (pre-COVID cohort). We compared patient characteristics, procedural characteristics and clinical outcomes. RESULTS: We examined 2131 patients who underwent TAVI (1020 patients in COVID cohort, 1111 patients in pre-COVID cohort). EuroSCORE II was comparable between cohorts (COVID 4.5 ± 4.0 vs pre-COVID 4.6 ± 4.2, p = 0.356). The number of TAVI procedures under general anaesthesia was lower in the COVID cohort (35.2% vs 46.5%, p < 0.001). Incidences of stroke (COVID 2.7% vs pre-COVID 1.7%, p = 0.134), major vascular complications (2.3% vs 3.4%, p = 0.170) and permanent pacemaker implantation (10.0% vs 9.4%, p = 0.634) did not differ between cohorts. Thirty-day and 150-day mortality were comparable (2.8% vs 2.2%, p = 0.359 and 5.2% vs 5.2%, p = 0.993, respectively). CONCLUSIONS: During the COVID-19 pandemic, patient characteristics and outcomes after TAVI were not different than before the pandemic. This highlights the fact that TAVI procedures can be safely performed during the COVID-19 pandemic, without an increased risk of complications or mortality.

The depletion thickness in solutions of semi-flexible polymers near colloidal surfaces: analytical approximations.

We derive a simple, yet accurate approximate mean-field expression for the depletion thickness δsf of a solution of dilute semi-flexible polymers next to a hard surface. In the case of a hard wall this equation has the simple form δsf = δ0[1 - tanh(psf/δ0)], where psf accounts for the degree of flexibility and δ0 is the depletion thickness in the case of fully flexible polymers. For fixed polymer coil size, increasing the chain stiffness leads to a decrease in the depletion thickness. The approach is also extended to include higher polymer concentrations in the semidilute regime. The analytical expressions are in quantitative agreement with numerical self-consistent field computations. A remarkable finding is that there is a maximum in the depletion thickness as a function of the chain stiffness in the semidilute concentration regime. This also means that depletion attractions between colloidal particles reach a maximum for a certain chain stiffness, which may have important implications for the phase stability of colloid-polymer mixtures. The derived equations could be useful for the description of interactions in- and phase stability of mixtures of colloids and semi-flexible polymers.

Sex-specific differences and how to handle them in early psoriatic arthritis.

OBJECTIVES: The prevalence of psoriatic arthritis (PsA) is the same in men and women; however, the latter experience a higher burden of disease and are affected more frequently by polyarthritis. Here, we performed an early PsA cohort analysis to assess sex-related differences in demographics, disease characteristics, and evolution over 1 year including applied treatment strategies. METHODS: Our study is embedded in the Dutch south-west Early Psoriatic Arthritis cohoRt. We described patient characteristics and treatment decisions. For the comparison across sexes and baseline and 1 year follow-up, appropriate tests depending on the distribution were used. RESULTS: Two hundred seventy-three men and 294 women with no significant differences in age and ethnicity were included. Women reported significantly longer duration of symptoms before diagnosis and significantly higher tender joint count, a higher disease activity, higher levels of pain, and lower functional capacity. Although minimal disease activity (MDA) rates increased over time for both sexes, MDA remained significantly more prevalent among men at 1 year (58.1% vs 35.7%, p < 0.00). Initially, treatment strategies were similar in both sexes with methotrexate being the most frequently used drug during the first year. Women received methotrexate for a shorter period [196 (93-364) vs 306 (157-365), p < 0.00] and therefore received a lower cumulative dose compared to men. Retention time was shorter for all DMARDs, and women had a delayed start on b-DMARDs. CONCLUSION: After 1 year of standard-of-care treatment, women did not surpass their baseline disadvantages. Despite the overall improvement, they still presented higher disease activity, higher levels of pain, and lower functional capacity score than men. The nature of these findings may advocate a need for sex specific adjustment of treatment strategies and evaluation in early PsA patients.

DEtection of ProxImal Coronary stenosis in the work-up for Transcatheter aortic valve implantation using CTA (from the DEPICT CTA collaboration).

OBJECTIVES: Computed tomography angiography (CTA) is performed routinely in the work-up for transcatheter aortic valve implantation (TAVI), and could potentially replace invasive coronary angiography (ICA) to rule out left main (LM) and proximal coronary stenosis. The objectives were to assess the diagnostic yield and accuracy of pre-TAVI CTA to detect LM and proximal coronary stenosis of ≥ 50% and ≥ 70% diameter stenosis (DS). METHODS: The DEPICT CTA database consists of individual patient data from four studies with a retrospective design that analyzed the diagnostic accuracy of pre-TAVI CTA to detect coronary stenosis, as compared with ICA. Pooled data were used to assess diagnostic accuracy to detect coronary stenosis in the left main and the three proximal coronary segments on a per-patient and a per-segment level. We included 1060 patients (mean age: 81.5 years, 42.7% male). RESULTS: On ICA, the prevalence of proximal stenosis was 29.0% (≥ 50% DS) and 15.7% (≥ 70% DS). Pre-TAVI CTA ruled out ≥ 50% DS in 51.6% of patients with a sensitivity of 96.4%, specificity of 71.2%, PPV of 57.7%, and NPV of 98.0%. For ≥ 70% DS, pre-TAVI CTA ruled out stenosis in 70.0% of patients with a sensitivity of 96.7%, specificity of 87.5%, PPV of 66.9%, and NPV of 99.0%. CONCLUSION: CTA provides high diagnostic accuracy to rule out LM and proximal coronary stenosis in patients undergoing work-up for TAVI. Clinical application of CTA as a gatekeeper for ICA would reduce the need for ICA in 52% or 70% of patients, using a threshold of ≥ 50% or ≥ 70% DS, respectively. KEY POINTS: • Clinical application of CTA as a gatekeeper for ICA would reduce the need for ICA in 52% or 70% of TAVI patients, using a threshold of ≥ 50% or ≥ 70% diameter stenosis. • The diagnostic accuracy of CTA to exclude proximal coronary stenosis in these patients is high, with a sensitivity of 96.4% and NPV of 98.0% for a threshold of ≥ 50%, and a sensitivity of 96.7% and NPV of 99.0% for a threshold of ≥ 70% diameter stenosis. • Atrial fibrillation and heart rate did not significantly affect sensitivity and NPV. However, a heart rate of < 70 b/min during CTA was associated with a significantly improved specificity and PPV.

The Impact of Percutaneous Coronary Intervention on Mortality in Patients With Coronary Lesions Who Underwent Transcatheter Aortic Valve Replacement.

OBJECTIVES: To analyze the effect of percutaneous coronary intervention (PCI) before transcatheter aortic valve replacement (TAVR) on all-cause and cardiovascular mortality after TAVR, differentiating between significant proximal lesions and the non-proximal (residual) lesions. METHODS: An institutional TAVR database was complemented with data on the extent of coronary artery disease (CAD), lesion location, lesion severity, and the location of PCI. Survival analysis was performed to investigate the impact on 6-month and 3-year mortality after TAVR in all patients and in subgroups of patients with significant proximal lesions (>70% diameter stenosis [DS], >50% DS in left main), the non-proximal residual lesions, and in a propensity score matched cohort. RESULTS: Among the 577 included patients, mean age was 83 years, 50% were female, and 31% had diabetes mellitus. Preprocedural PCI of unselected lesions was independently associated with increased 6-month mortality (hazard ratio, 2.2; 95% confidence interval, 1.0-4.6; P=.04), but selective PCI of significant proximal lesions did not have an association with higher mortality, nor did we find a significant effect of PCI on mortality in the propensity-matched cohort. CONCLUSION: Routine pre-TAVR PCI is not associated with mortality reduction in TAVR patients with coronary lesions in any segment or in patients with proximal coronary lesions. Despite the lack of a beneficial effect of routine pre-TAVR PCI, we cannot exclude a beneficial effect in a selection of patients with proximal lesions. Therefore, we strongly support the current clinical guidelines to only consider pre-TAVR PCI in proximal coronary lesions, while advocating a restrictive pre-TAVR PCI strategy.

Cangrelor Use in Routine Practice: A Two-Center Experience.

Cangrelor is the first and only intravenous P2Y12-inhibitor and is indicated when (timely) administration of an oral P2Y12 inhibitor is not feasible in patients undergoing percutaneous coronary intervention (PCI). Our study evaluated the first years of cangrelor use in two Dutch tertiary care centers. Cangrelor-treated patients were identified using a data-mining algorithm. The cumulative incidences of all-cause death, myocardial infarction, definite stent thrombosis and major bleeding at 48 h and 30 days were assessed using Kaplan-Meier estimates. Predictors of 30-day mortality were identified using uni- and multivariable Cox regression models. Between March 2015 and April 2021, 146 patients (median age 63.7 years, 75.3% men) were treated with cangrelor. Cangrelor was primarily used in ST-segment elevation myocardial infarction (STEMI) patients (84.2%). Approximately half required cardiopulmonary resuscitation (54.8%) or mechanical ventilation (48.6%). The cumulative incidence of all-cause death was 11.0% and 25.3% at 48 h and 30 days, respectively. Two cases (1.7%) of definite stent thrombosis, both resulting in myocardial infarction, occurred within 30 days, but after 48 h. No other cases of recurrent myocardial infarction transpired within 30 days. Major bleeding occurred in 5.6% and 12.5% of patients within 48 h and 30 days, respectively. Cardiac arrest at presentation was an independent predictor of 30-day mortality (adjusted hazard ratio 5.20, 95%-CI: 2.10-12.9, p < 0.01). Conclusively, cangrelor was used almost exclusively in STEMI patients undergoing PCI. Even though cangrelor was used in high-risk patients, its use was associated with a low rate of stent thrombosis.

Long-term 5-year outcome of the randomized IMPRESS in severe shock trial: percutaneous mechanical circulatory support vs. intra-aortic balloon pump in cardiogenic shock after acute myocardial infarction.

AIMS: To assess differences in long-term outcome and functional status of patients with cardiogenic shock (CS) treated by percutaneous mechanical circulatory support (pMCS) and intra-aortic balloon pump (IABP). METHODS AND RESULTS: Long-term follow-up of the multicentre, randomized IMPRESS in Severe Shock trial (NTR3450) was performed 5-year after initial randomization. Between 2012 and 2015, a total of 48 patients with severe CS from acute myocardial infarction (AMI) with ST-segment elevation undergoing immediate revascularization were randomized to pMCS by Impella CP (n = 24) or IABP (n = 24). For the 5-year assessment, all-cause mortality, functional status, and occurrence of major adverse cardiac and cerebrovascular event (MACCE) were assessed. MACCE consisted of death, myocardial re-infarction, repeat percutaneous coronary intervention, coronary artery bypass grafting, and stroke. Five-year mortality was 50% (n = 12/24) in pMCS patients and 63% (n = 15/24) in IABP patients (relative risk 0.87, 95% confidence interval 0.47-1.59, P = 0.65). MACCE occurred in 12/24 (50%) of the pMCS patients vs. 19/24 (79%) of the IABP patients (P = 0.07). All survivors except for one were in New York Heart Association Class I/II [pMCS n = 10 (91%) and IABP n = 7 (100%), P = 1.00] and none of the patients had residual angina. There were no differences in left ventricular ejection fraction between the groups (pMCS 52 ± 11% vs. IABP 48 ± 10%, P = 0.53). CONCLUSIONS: In this explorative randomized trial of patients with severe CS after AMI, there was no difference in long-term 5-year mortality between pMCS and IABP-treated patients, supporting previously published short-term data and in accordance with other long-term CS trials.

Implementation of CT Coronary Angiography as an Alternative to Invasive Coronary Angiography in the Diagnostic Work-Up of Non-Coronary Cardiac Surgery, Cardiomyopathy, Heart Failure and Ventricular Arrhythmias.

To assess the need for additional invasive coronary angiography (CAG) after initial computed tomography coronary angiography (CTCA) in patients awaiting non-coronary cardiac surgery and in patients with cardiomyopathy, heart failure or ventricular arrhythmias, and to determine differences between patients that were referred to initial CTCA or direct CAG, consecutive patients were included between August 2017 and January 2020 and categorized as those referred to initial CTCA (conform protocol), and to direct CAG (non-conform protocol). Out of a total of 415 patients, 78.8% (327 patients, mean age: 57.9 years, 67.3% male) were referred to initial CTCA, of whom 260 patients (79.5%) had no obstructive lesions (<50% DS). A total of 55 patients (16.8%) underwent additional CAG after initial CTCA, which showed coronary lesions of >50% DS in 21 patients (6.3% of 327). Eighty-eight patients (mean age: 66.0 years, 59.1% male) were directly referred to CAG (non-conform protocol). These patients were older and had more cardiovascular risk factors compared to patients that underwent initial CTCA (conform protocol), and coronary lesions of >50% DS were detected in 16 patients (17.2%). Revascularization procedures were infrequently performed in both groups: initial CTCA (3.0%), direct CAG (3.4%). The use of CTCA as a gatekeeper CAG in the diagnostic work-up of non-coronary cardiac surgery, cardiomyopathy, heart failure and ventricular arrhythmias is feasible, and only 17% of these patients required additional CAG after initial CTCA. Therefore, CTCA should be considered as the initial imaging modality to rule out CAD in these patients.

Phase separation in mixed suspensions of bacteria and nonadsorbing polymers.

The shapes of bacteria can vary widely; they may, for instance, be spherical, rod-like, string-like, or curved. In general, bacilli are highly anisotropic. For research and (bio)technological purposes, it can be useful to concentrate bacteria, which is possible by adding nonadsorbing polymers. The induced phase separation originates from a polymer-mediated depletion interaction, first understood by Asakura and Oosawa. Here, it is shown that free volume theory (FVT) can semi-quantitatively describe the phase transitions observed when adding sodium polystyrene sulfonate polymers to E. coli bacteria [Schwarz-Linek et al., Soft Matter 6, 4540 (2010)] at high ionic strength. The E. coli bacteria are described as short, hard spherocylinders. FVT predicts that the phase transitions of the mixtures result from a fluid-ABC crystal solid phase coexistence of a hard spherocylinder-polymer mixture.

Update and, internal and temporal-validation of the FRANCE-2 and ACC-TAVI early-mortality prediction models for Transcatheter Aortic Valve Implantation (TAVI) using data from the Netherlands heart registration (NHR).

BACKGROUND: The predictive performance of the models FRANCE-2 and ACC-TAVI for early-mortality after Transcatheter Aortic Valve Implantation (TAVI) can decline over time and can be enhanced by updating them on new populations. We aim to update and internally and temporally validate these models using a recent TAVI-cohort from the Netherlands Heart Registration (NHR). METHODS: We used data of TAVI-patients treated in 2013-2017. For each original-model, the best update-method (model-intercept, model-recalibration, or model-revision) was selected by a closed-testing procedure. We internally validated both updated models with 1000 bootstrap samples. We also updated the models on the 2013-2016 dataset and temporally validated them on the 2017-dataset. Performance measures were the Area-Under ROC-curve (AU-ROC), Brier-score, and calibration graphs. RESULTS: We included 6177 TAVI-patients, with 4.5% observed early-mortality. The selected update-method for FRANCE-2 was model-intercept-update. Internal validation showed an AU-ROC of 0.63 (95%CI 0.62-0.66) and Brier-score of 0.04 (0.04-0.05). Calibration graphs show that it overestimates early-mortality. In temporal-validation, the AU-ROC was 0.61 (0.53-0.67).The selected update-method for ACC-TAVI was model-revision. In internal-validation, the AU-ROC was 0.63 (0.63-0.66) and Brier-score was 0.04 (0.04-0.05). The updated ACC-TAVI calibrates well up to a probability of 20%, and subsequently underestimates early-mortality. In temporal-validation the AU-ROC was 0.65 (0.58-0.72). CONCLUSION: Internal-validation of the updated models FRANCE-2 and ACC-TAVI with data from the NHR demonstrated improved performance, which was better than in external-validation studies and comparable to the original studies. In temporal-validation, ACC-TAVI outperformed FRANCE-2 because it suffered less from changes over time.

Lessons learned from clinical phenotypes in early psoriatic arthritis: the real-world Dutch south west Early Psoriatic ARthritis study.

Objective: This paper describes the baseline demographics, clinical characteristics, and patient-reported outcomes (PROs) according to clinical phenotype of patients with early psoriatic arthritis (PsA) for the purpose of creating a decision support system for daily clinical practice.Method: Patients with newly diagnosed PsA were included in the Dutch south west Early Psoriatic ARthritis (DEPAR) study. No classification criteria were applied, to ensure collection of real-world data on demographics, medication, clinical characteristics, and PROs. An IT infrastructure facilitated data collection.Results: We described 527 patients, categorized according to the clinical phenotype stated by the rheumatologist at the time of diagnosis, namely monoarthritis (15%), oligoarthritis (40%), polyarthritis (23%), enthesitis (10%), axial disease (2%), and dactylitis (10%). Overall psoriasis severity was mild and 83 patients (16%) had no psoriasis. Short-term sick leave (> 1 day per 4 weeks) was 17% and long-term sick leave (> 4 weeks) was 4%. The group with phenotype enthesitis reported the longest duration of complaints, had the highest fatigue scores, and contained the highest percentage of patients with a Hospital Anxiety and Depression Scale (HADS) anxiety score ≥ 8 and depression score ≥ 8.Conclusion: PsA patients presenting at outpatient clinics in the Netherlands had a mild degree of psoriasis, with impairment of quality of life and work productivity. Most patients presented with phenotype oligoarthritis. Those presenting with phenotype enthesitis more often reported scores suggestive of an anxiety or depression disorder and fatigue. It is important for attending rheumatologists to be aware of these differences when assessing patients with PsA.

Defying the Gibbs Phase Rule: Evidence for an Entropy-Driven Quintuple Point in Colloid-Polymer Mixtures.

Using a minimal algebraic model for the thermodynamics of binary rod-polymer mixtures, we provide evidence for a quintuple phase equilibrium; an observation that seems to be at odds with the Gibbs phase rule for two-component systems. Our model is based on equations of state for the relevant liquid crystal phases that are in quantitative agreement with computer simulations. We argue that the appearance of a quintuple equilibrium, involving an isotropic fluid, a nematic and smectic liquid crystal, and two solid phases, can be reconciled with a generalized Gibbs phase rule in which the two intrinsic length scales of the athermal colloid-polymer mixture act as additional field variables.

Algebraic equations of state for the liquid crystalline phase behavior of hard rods.

Based on simplifications of previous numerical calculations [H. Graf and H. Löwen, Phys. Rev. E 59, 1932 (1999)1063-651X10.1103/PhysRevE.59.1932], we propose algebraic free energy expressions for the smectic-A liquid crystal phase and the crystal phases of hard spherocylinders. Quantitative agreement with simulations is found for the resulting equations of state. The free energy expressions can be used to straightforwardly compute the full phase behavior for all aspect ratios and to provide a suitable benchmark for exploring how attractive interrod interactions mediate the phase stability through perturbation approaches such as free-volume or van der Waals theory.