Synthesis and comparative studies of phase transition behaviour of new dimeric liquid crystals consisting of dimethyluracil and biphenyl cores

A new homologous series of mesogens containing 6-amino-1,3-dimethyluracil moiety have been synthesized. The structures of the compounds were characterised by elemental analysis, FT-IR, 1H and 13C NMR spectroscopic techniques. Their mesomorphic properties were studied by polarising optical microscopy attached to a heating stage. Microscopy data were supported with transition temperatures and enthalpy change values obtained from the differential scanning calorimetry analysis. The studies have shown that the mesomorphic properties of the compounds are dependent on the lengths of alkoxy-spacers. Compounds 4a-f with a shorter alkoxy-spacer chain (n = 6) exhibited smectic A phase, while compounds 4g-r with a alkoxy-spacer chain (n = 8 or 10) displayed nematic phase

Facile, One-Pot Synthesis of Aromatic Diamine-Based Phosphinated Benzoxazines and Their Flame-Retardant Thermosets

Three aromatic diamine-based, phosphinated benzoxazines (7-9) were prepared from three typical aromatic diamines-4,4'-diamino diphenyl methane (1), 4,4'-diamino diphenyl sulfone (2), and 4,4'-diamino diphenyl ether (3) by a one-pot procedure. To clarify the reaction mechanism, a two-pot procedure was applied, in which the reaction intermediates (4-6) were isolated for characterization. The structures of intermediates and benzoxazines were confirmed by high resolution mass, IR, and 1D and 2D-NMR spectra. In addition to self-polymerization, (7-9) were copolymerized with cresol novolac epoxy (CNE). After curing, the homopolymers of P(7-9) are brittle while the copolymers of (7-9)/CNE are tough. Dynamic mechanical analysis shows the T(g)s of (7-9)/CNE copolymers are 187, 190, and 171 degrees C, respectively. Thermal mechanical analysis shows the CTEs of (7-9)/CNE copolymers are 46, 38, and 46 ppm, respectively. All the (7-9)/CNE copolymers belong to an UL-94 V-0 grade, demonstrating good flame retardancy. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4555-4566, 201

Quality of life after catheter and minimally invasive surgical ablation of paroxysmal and early persistent atrial fibrillation: results from the SCALAF trial

Contains fulltext : 229201.pdf (Publisher’s version ) (Closed access)AIMS: In the SCALAF trial, catheter-based pulmonary vein isolation (PVI) was as effective in long-term prevention of atrial fibrillation (AF) as minimally invasive thoracoscopic PVI and left atrial appendage ligation (MIPI). Catheter ablation (CA) resulted in significantly less major complications as compare to MIPI. We report quality of life (QOL) outcome in these patients. METHODS: In this study, 52 patients with symptomatic paroxysmal or early persistent AF were randomized to either MIPI or CA. QOL was assessed at baseline, 3, 6, and 12 months follow-up using the SF-36 Health Survey Questionnaire. AF-related symptoms were quantified at each follow-up visit using the European Heart Rhythm Association (EHRA) score. RESULTS: Median age was 57 years and 78% was male. Paroxysmal AF was present in 74%. At 3 months follow-up, physical role limitations (88.2 +/- 29.5; versus 40.9 +/- 44.0; P = 0.001, respectively) and bodily pain scores (95.5 +/- 8.7; versus 76.0 +/- 27.8; P = 0.021, respectively) were significantly higher after CA compared to MIPI, indicating less limitation in daily activity caused by physical problems and less pain after CA than after MIPI. AF symptoms assessed by the EHRA scores improved significantly at 3, 6, 12, and 24 months compared to baseline in both treatment groups (P < 0.001), with no significant differences between treatment groups. CONCLUSIONS: CA and MIPI ablation of AF both resulted in an improvement in several QOL measurements, although CA resulted in significantly less physical problems and bodily pain 3 months after treatment compared to MIPI. CLINICAL TRIAL NUMBER: ClinicalTrials.gov identifier: NCT00703157

Randomized Controlled Trial of Surgical Versus Catheter Ablation for Paroxysmal and Early Persistent Atrial Fibrillation

Contains fulltext : 200354.pdf (Publisher’s version ) (Closed access)BACKGROUND: Current guidelines recommend both percutaneous catheter ablation (CA) and surgical ablation in the treatment of atrial fibrillation, with different levels of evidence. No direct comparison has been made between minimally invasive thoracoscopic pulmonary vein isolation with left atrial appendage ligation (surgical MIPI) versus percutaneous CA comprising of pulmonary vein isolation as primary treatment of atrial fibrillation. We, therefore, conducted a randomized controlled trial comparing the safety and efficacy of these 2 treatment modalities. METHODS: Eighty patients were enrolled in the study and underwent implantable loop recorder implantation. Twenty-eight patients did not reach randomization criteria. A total of 52 patients with symptomatic paroxysmal or early persistent atrial fibrillation were randomized, 26 to CA and 26 to surgical MIPI. The primary end point was defined as freedom of atrial tachyarrhythmias, without the use of antiarrhythmic drugs. The safety end point was freedom of complications. RESULTS: Median age was 57 years (range, 37-75), and 78% were men. Paroxysmal atrial fibrillation was present in 74%. Follow-up duration was >/=2 years in all patients. CA was noninferior to MIPI in terms of single-procedure arrhythmia-free survival after 2 years of follow-up (56.0% versus 29.2%; HR, 0.56; 95% CI, 0.26-1.20; log-rank P=0.059). Procedure-related major adverse events occurred significantly more often in MIPI than CA (20.8% versus 0%; P=0.029). CONCLUSIONS: Percutaneous pulmonary vein isolation was noninferior to MIPI in terms of efficacy and resulted in less complications. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00703157