Preparation and Characterization of Porous Titania Ceramic Scaffolds

Biocompatible ceramics have recently attracted increasing attention as porous scaffolds that stimulate and guide natural bone regeneration. Due to excellent biocompatibility of titania (titanium dioxide or TiO2) porous three-dimensional (3D) TiO2 structures have been proposed as promising scaffolding materials for inducing bone formation from the surrounding environment and for enhancement of vascularisation after implantation. In this paper, 3D porous TiO2 ceramic scaffolds were produced via polymer foam replica method. This work deals with several important issues that are considered to be important for 3D scaffolds applied to regenerate bone tissue: pore size, porosity and mechanical strength. TiO2 ceramic scaffolds with pore size 300 μm − 700 μm and porosity > 90 % were obtained. Scaffolds showed fully open and interconnected pore structure that remained after recoating them with low viscosity TiO2 slurry. By optimising thermal treatment conditions grain growth and collapse of struts could be controlled in a way that resulted in higher compressive strength. Recoating greatly improved compressive strength and it reached 0.74±0.08 MPa after two coatings without causing changes in the open porestructure

Effect of Intumescent Flame Retardants on the Properties of Polyurethanes Based on Tall Oil Fatty Acids Esters

Normal 0 false false false MicrosoftInternetExplorer4 The efficiency of using intumescent flame retardants in polyurethane coatings based on tall oil fatty acids esters was assessed. The influence of the content of each of the flame retardants (ammonium polyphosphate, melamine and pentaerythriol) separately on the flammability parameters of wood samples with polyurethane coatings in a cone calorimeter test, as well as on the thermal and mechanical properties of the polyurethane itself, were investigated. the effect of the ratios of double and triple combinations of the mentioned flame retardants on the specified properties was studied. It has been found that, for the given type of polyester urethane, ammonium polyphosphate decreases the flammability of polyurethane to the greatest extent. Melamine, and melamine in combination with ammonium polyphosphate, decrease the smoke release upon polyurethane combustion. DOI: http://dx.doi.org/10.5755/j01.ms.21.2.5784</p

Influence of Long-Term Storage and UV Light Exposure on Characteristics of Polyurethane Foams for Cryogenic Insulation

Rigid polyurethane (PUR) foams have been the most effective insulation material used in space launchers since the beginning of cryogenic fuel use, due to their outstanding thermal and mechanical properties. In this study, spray-applied PUR foams using different ratios of amine-based catalysts were produced. Due to climate change, several restrictions have been made regarding the usage of blowing agents used for PUR foam production. Lately, hydrofluoroolefins (HFOs) have been suggested as an alternative for PUR foam production due to their low global warming potential (GWP) and ozone depletion potential (ODP), replacing the hydrofluorocarbons (HFCs) so far used. This change in blowing agents naturally altered the usage of catalysts. Reactive amine-based catalysts are less hazardous because of their low volatility and ability to react successfully with isocyanate or polyols. Spray-applied PUR foams with a potential application for cryogenic insulation were produced and tested for long-term storage, analyzing parameters such as the pH value of polyol composition, foaming kinetics (trise, tcream), etc. Athermal analysis (TG, DSC) was also applied to developed materials, as well as artificial ageing by exposing samples to UV light. It was discovered that PUR foams obtained using reactive amine-based catalysts, such as Polycat 203 and 218, have a higher integral heat capacity, but polyol mixtures containing these catalysts cannot exceed a storage time of more than 4 months. It was also observed from artificial ageing tests of PUR cryogenic insulation by exposure to UV light that the thickness of the degraded layer reached 0.8 mm (after 1000 h), but no significant destruction of cellular structure deeper in the material was observed

Preparation and Characterization of Porous Titania Ceramic Scaffolds

Biocompatible ceramics have recently attracted increasing attention as porous scaffolds that stimulate and guide natural bone regeneration. Due to excellent biocompatibility of titania (titanium dioxide or TiO2) porous three-dimensional (3D) TiO2 structures have been proposed as promising scaffolding materials for inducing bone formation from the surrounding environment and for enhancement of vascularisation after implantation. In this paper, 3D porous TiO2 ceramic scaffolds were produced via polymer foam replica method. This work deals with several important issues that are considered to be important for 3D scaffolds applied to regenerate bone tissue: pore size, porosity and mechanical strength. TiO2 ceramic scaffolds with pore size 300 μm − 700 μm and porosity > 90 % were obtained. Scaffolds showed fully open and interconnected pore structure that remained after recoating them with low viscosity TiO2 slurry. By optimising thermal treatment conditions grain growth and collapse of struts could be controlled in a way that resulted in higher compressive strength. Recoating greatly improved compressive strength and it reached 0.74±0.08 MPa after two coatings without causing changes in the open pore structure

Influence of Reactive Amine-Based Catalysts on Cryogenic Properties of Rigid Polyurethane Foams for Space and On-Ground Applications

Rigid polyurethane (PUR) foams have outstanding properties, and some of them are successfully used even today as cryogenic insulation. The fourth-generation blowing agent Solstice® LBA and commercial polyols were used for the production of a low-density cryogenic PUR foam composition. A lab-scale pouring method for PUR foam preparation and up-scaling of the processes using an industrial spraying machine are described in this article. For the determination of the foam properties at cryogenic temperature, original methods, devices, and appliances were used. The properties at room and cryogenic temperatures of the developed PUR foams using a low-toxicity, bismuth-based, and low-emission amine catalyst were compared with a reference foam with a conventional tin-based additive amine catalyst. It was found that the values of important cryogenic characteristics such as adhesion strength after cryoshock and the safety coefficient of the PUR foams formed with new reactive-type amine-based catalysts and with the blowing agent Solstice® LBA were higher than those of the foam with conventional catalysts

Современные подходы к ведению детей с острым обструктивным ларингитом и эпиглоттитом

Experts of the Union of Pediatricians of Russia have developed modern guidelines on the management of children with acute obstructive laryngitis and epiglottitis. Croup is the most common cause of acute upper respiratory obstruction in children aged from 6 months to 6 years. Usually respiratory viruses are the pathogenic agents of the disease. The etiological factor of epiglottitis is Haemophilus influenzae type b in the vast majority of cases (&gt; 90%). However, nowadays, epiglottitis caused by this pathogen agent is more common in adults in countries with mass immunization against hemophilic infection. This article considers in detail etiology, pathogenesis, and classification issues. Special attention is given to diagnosis, differential diagnosis, and therapy (via evidence-based approach) of acute obstructive laryngitis in children.Экспертами Союза педиатров России разработаны актуальные методические рекомендации по оказанию медицинской помощи детям с острым обструктивным ларингитом и эпиглоттитом. Круп — это наиболее частая причина острой обструкции верхних дыхательных путей у детей в возрасте от 6 мес до 6 лет. Как правило, возбудителями заболевания являются респираторные вирусы. Этиологическим фактором эпиглоттита в подавляющем большинстве случаев выступает Haemophilus influenzae типа b (&gt; 90%). Однако в настоящее время в странах с массовой иммунизацией против гемофильной инфекции эпиглоттит, вызванный данным возбудителем, чаще встречается у взрослых. В статье подробно рассмотрены вопросы этиологии, патогенеза, классификации. Особое внимание уделено диагностике, дифференциальной диагностике и терапии острого обструктивного ларингита у детей, основанным на принципах доказательности

Rationale, design, and baseline characteristics in Evaluation of LIXisenatide in Acute Coronary Syndrome, a long-term cardiovascular end point trial of lixisenatide versus placebo

BACKGROUND: Cardiovascular (CV) disease is the leading cause of morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). Furthermore, patients with T2DM and acute coronary syndrome (ACS) have a particularly high risk of CV events. The glucagon-like peptide 1 receptor agonist, lixisenatide, improves glycemia, but its effects on CV events have not been thoroughly evaluated. METHODS: ELIXA (www.clinicaltrials.gov no. NCT01147250) is a randomized, double-blind, placebo-controlled, parallel-group, multicenter study of lixisenatide in patients with T2DM and a recent ACS event. The primary aim is to evaluate the effects of lixisenatide on CV morbidity and mortality in a population at high CV risk. The primary efficacy end point is a composite of time to CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for unstable angina. Data are systematically collected for safety outcomes, including hypoglycemia, pancreatitis, and malignancy. RESULTS: Enrollment began in July 2010 and ended in August 2013; 6,068 patients from 49 countries were randomized. Of these, 69% are men and 75% are white; at baseline, the mean ± SD age was 60.3 ± 9.7 years, body mass index was 30.2 ± 5.7 kg/m(2), and duration of T2DM was 9.3 ± 8.2 years. The qualifying ACS was a myocardial infarction in 83% and unstable angina in 17%. The study will continue until the positive adjudication of the protocol-specified number of primary CV events. CONCLUSION: ELIXA will be the first trial to report the safety and efficacy of a glucagon-like peptide 1 receptor agonist in people with T2DM and high CV event risk

Ticagrelor in patients with diabetes and stable coronary artery disease with a history of previous percutaneous coronary intervention (THEMIS-PCI) : a phase 3, placebo-controlled, randomised trial

Background: Patients with stable coronary artery disease and diabetes with previous percutaneous coronary intervention (PCI), particularly those with previous stenting, are at high risk of ischaemic events. These patients are generally treated with aspirin. In this trial, we aimed to investigate if these patients would benefit from treatment with aspirin plus ticagrelor. Methods: The Effect of Ticagrelor on Health Outcomes in diabEtes Mellitus patients Intervention Study (THEMIS) was a phase 3 randomised, double-blinded, placebo-controlled trial, done in 1315 sites in 42 countries. Patients were eligible if 50 years or older, with type 2 diabetes, receiving anti-hyperglycaemic drugs for at least 6 months, with stable coronary artery disease, and one of three other mutually non-exclusive criteria: a history of previous PCI or of coronary artery bypass grafting, or documentation of angiographic stenosis of 50% or more in at least one coronary artery. Eligible patients were randomly assigned (1:1) to either ticagrelor or placebo, by use of an interactive voice-response or web-response system. The THEMIS-PCI trial comprised a prespecified subgroup of patients with previous PCI. The primary efficacy outcome was a composite of cardiovascular death, myocardial infarction, or stroke (measured in the intention-to-treat population). Findings: Between Feb 17, 2014, and May 24, 2016, 11 154 patients (58% of the overall THEMIS trial) with a history of previous PCI were enrolled in the THEMIS-PCI trial. Median follow-up was 3·3 years (IQR 2·8–3·8). In the previous PCI group, fewer patients receiving ticagrelor had a primary efficacy outcome event than in the placebo group (404 [7·3%] of 5558 vs 480 [8·6%] of 5596; HR 0·85 [95% CI 0·74–0·97], p=0·013). The same effect was not observed in patients without PCI (p=0·76, p interaction=0·16). The proportion of patients with cardiovascular death was similar in both treatment groups (174 [3·1%] with ticagrelor vs 183 (3·3%) with placebo; HR 0·96 [95% CI 0·78–1·18], p=0·68), as well as all-cause death (282 [5·1%] vs 323 [5·8%]; 0·88 [0·75–1·03], p=0·11). TIMI major bleeding occurred in 111 (2·0%) of 5536 patients receiving ticagrelor and 62 (1·1%) of 5564 patients receiving placebo (HR 2·03 [95% CI 1·48–2·76], p<0·0001), and fatal bleeding in 6 (0·1%) of 5536 patients with ticagrelor and 6 (0·1%) of 5564 with placebo (1·13 [0·36–3·50], p=0·83). Intracranial haemorrhage occurred in 33 (0·6%) and 31 (0·6%) patients (1·21 [0·74–1·97], p=0·45). Ticagrelor improved net clinical benefit: 519/5558 (9·3%) versus 617/5596 (11·0%), HR=0·85, 95% CI 0·75–0·95, p=0·005, in contrast to patients without PCI where it did not, p interaction=0·012. Benefit was present irrespective of time from most recent PCI. Interpretation: In patients with diabetes, stable coronary artery disease, and previous PCI, ticagrelor added to aspirin reduced cardiovascular death, myocardial infarction, and stroke, although with increased major bleeding. In that large, easily identified population, ticagrelor provided a favourable net clinical benefit (more than in patients without history of PCI). This effect shows that long-term therapy with ticagrelor in addition to aspirin should be considered in patients with diabetes and a history of PCI who have tolerated antiplatelet therapy, have high ischaemic risk, and low bleeding risk

Lipoprotein(a) and Benefit of PCSK9 Inhibition in Patients With Nominally Controlled LDL Cholesterol

International audienceBackground: Guidelines recommend nonstatin lipid-lowering agents in patients at very high risk for major adverse cardiovascular events (MACE) if low-density lipoprotein cholesterol (LDL-C) remains ≥70 mg/dL on maximum tolerated statin treatment. It is uncertain if this approach benefits patients with LDL-C near 70 mg/dL. Lipoprotein(a) levels may influence residual risk.Objectives: In a post hoc analysis of the ODYSSEY Outcomes (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) trial, the authors evaluated the benefit of adding the proprotein subtilisin/kexin type 9 inhibitor alirocumab to optimized statin treatment in patients with LDL-C levels near 70 mg/dL. Effects were evaluated according to concurrent lipoprotein(a) levels.Methods: ODYSSEY Outcomes compared alirocumab with placebo in 18,924 patients with recent acute coronary syndromes receiving optimized statin treatment. In 4,351 patients (23.0%), screening or randomization LDL-C was 13.7 mg/dL or ≤13.7 mg/dL; corresponding adjusted treatment hazard ratios were 0.82 (95% CI: 0.72-0.92) and 0.89 (95% CI: 0.75-1.06), with Pinteraction = 0.43.Conclusions: In patients with recent acute coronary syndromes and LDL-C near 70 mg/dL on optimized statin therapy, proprotein subtilisin/kexin type 9 inhibition provides incremental clinical benefit only when lipoprotein(a) concentration is at least mildly elevated. (ODYSSEY Outcomes: Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab; NCT01663402)