ABSTRACT
Surface templating via self-assembly of hydrogen-bonded molecular networks is a rapidly developing bottom-up approach in nanotechnology. Using the melamine-PTCDI molecular system as an example we show theoretically that the network stability in the parameter space of temperature versus molecular coupling anisotropy is highly restricted. Our kinetic Monte Carlo simulations predict a structural stability diagram that contains domains of stability of an open honeycomb network, a compact phase, and a high-temperature disordered phase. The results are in agreement with recent experiments, and reveal a relationship between the molecular size and the network stability, which may be used to predict an upper limit on pore-cavity sizes.
Subject(s)
Imides/chemistry , Models, Chemical , Nanostructures/chemistry , Perylene/analogs & derivatives , Triazines/chemistry , Anisotropy , Computer Simulation , Hydrogen Bonding , Monte Carlo Method , Perylene/chemistryABSTRACT
AIM: This study evaluated the advantages of 'selective' over 'non-selective' antiarrhythmic prevention of atrial fibrillation after coronary surgery based on a new risk prediction algorithm. METHODS AND RESULTS: In a retrospective analysis of a prospective randomized trial, a model for risk prediction was determined based on clinical data of the control group (A; n = 107) and tested in a test group (B; n = 107, treated with low dose sotalol). Using this algorithm, the effect of a 'selective' antiarrhythmic approach in high-risk patients was compared to a 'non-selective' approach, where all patients were treated. In total, 75 (35%) patients developed atrial fibrillation and 14 (7%) side-effects led to discontinuation of study medication. Based on the risk prediction algorithm, 36% of group A patients were classified as high-risk patients with an incidence of atrial fibrillation of 76% compared to 26% in low-risk patients (P < 0.0001). The selective approach, i.e. treatment of high-risk patients only reduced the incidence of atrial fibrillation from 76% to 50% (P = 0.0295) compared to a reduction from 44% to 26% (P = 0.0065) when all patients were treated. More importantly, with the non-selective approach 100% of patients were exposed to the possible side-effects of sotalol and costs compared to 24% only with the selective approach (P < 0.0001). CONCLUSIONS: Thus, a selective approach based on a clinical risk prediction algorithm should improve the cost-effectiveness and safety of low-dose sotalol in the prevention of atrial fibrillation after coronary bypass surgery.
Subject(s)
Anti-Arrhythmia Agents/administration & dosage , Atrial Fibrillation/prevention & control , Coronary Artery Bypass , Postoperative Complications/prevention & control , Sotalol/administration & dosage , Adult , Aged , Algorithms , Anti-Arrhythmia Agents/adverse effects , Atrial Fibrillation/diagnosis , Dose-Response Relationship, Drug , Double-Blind Method , Electrocardiography/drug effects , Female , Humans , Male , Middle Aged , Postoperative Complications/diagnosis , Prospective Studies , Risk Assessment , Sotalol/adverse effectsABSTRACT
We report the case of a 50-year-old female in whom the connection between hypocalcemia and heart failure was not made until a second hospital admission for left ventricular failure. Under appropriate calcium supplementation the symptoms were relieved within 2 days and the patient remained well thereafter. The hypocalcemia was found to be caused by autoimmune hypoparathyroidism. Heart failure due to hypocalcemia has been rarely reported, and even in textbooks the subject is poorly documented. The physiologic functions of calcium and the implications of deficiency for heart muscle are outlined, with a review of the literature. A treatment regimen for hypocalcemia is recommended.
