Simultaneous improvements in antibacterial and flame retardant properties of PET by use of bio-nanotechnology for fabrication of high performance PET bionanocomposites.

Recently, attentions to the applications of biotechnology and nanotechnology in the polymer industries have been greater than before. Hybrid nanocomposites containing multi-type of nano structures are widely established, but application of biotechnology for in-situ embedment of nanoparticles in polymer matrix is rarely reported. In this study, poly (ethylene terephthalate) (PET) based ternary bionanocomposites containing modified chitosan (phosphorylated chitosan) and nanosilver particles were prepared by simple eco-friendly method. Chitosan was selected as a biopolymer with respect to the biological activity and compatibility with PET. Phosphorylation of chitosan was achieved in order to introduce the phosphorus moieties as a flame retardant agent in PET matrix by using chemical approach. Also a cost-effective and environmentally friendly method was used for the in-situ fabrication and decoration of silver nanoparticles on to phosphorylated chitosan in PET matrix. Effects of the hybrid system (phosphorylated chitosan and silver nanoparticles) on the morphology, thermal behavior and antibacterial properties of the PET samples were investigated by different methods. The microstructure and homogeneity of the samples were analyzed by studying of dispersion of nanoparticles in PET via scanning electron microscopy. The antibacterial properties of PET nanocomposites can be improved by insertion of silver nanoparticles into the bulk of polymer matrix. Obtained results indicated that the PET/phosphorylated chitosan/silver nanocomposites showed a significantly higher growth inhibition rate compared with the PET and PET/phosphorylated chitosan blend. Also the flame retardant properties of PET nanocomposites were drastically enhanced.

The Prevalence and Factors Contributing to Hemodynamic Depression in Patients Undergoing Carotid Angioplasty and Stenting.

BACKGROUND: Hemodynamic depression, including bradycardia and hypotension, is among the most common complications of carotid angioplasty and stenting. METHODS AND MATERIAL: A prospective, cross-sectional study was conducted at Shiraz University of Medical Sciences in southern Iran from 2011 to 2013. Consecutive patients undergoing carotid angioplasty and stenting were included. Demographic data, atherosclerotic risk factors, preprocedural blood pressure, the site of stenosis, the degree of stenosis, and data regarding technical factors were recorded. Hemodynamic depression was defined as a systolic blood pressure less than 90 mmHg and/or heart rate less than 50 beat/min. RESULTS: About 170 patients (67% male, mean age: 71+9.8, 55.9% right side, 82.9% symptomatic) were recruited. Mean degree of stenosis was 79.4% in operated side and 40.7% in nonoperated side. Predilation, postdilation, or both were conducted in 18(10.5%), 141(83%), 11(6.5%) patients respectively. Thirteen (7.6%), 41(24%), and 12(7%) of patients developed postprocedural bradycardia, hypotension or both, respectively. Two patients had a stroke after CAS and periprocedural mortality was 0%. Hemodynamic depression after CAS had a significant association with preprocedure blood pressure and the use of an open cell stent design, but not with atherosclerotic risk factors, site and/or degree of stenosis, predilation, or postdilation. Hemodynamic depression significantly increased hospital stay too. CONCLUSION: Preprocedural hydration and close-cell stents may decrease the risk of poststenting hemodynamic depression.

Demographic and Technical Risk Factors of 30-Day Stroke, Myocardial Infarction, and/or Death in Standard- and High-Risk Patients Who Underwent Carotid Angioplasty and Stenting.

BACKGROUND: Carotid angioplasty and stenting (CAS) is an accepted treatment to prevent stroke in patients with carotid artery stenosis. The purpose of this study is to identify risk factors for major complications after CAS. MATERIALS AND METHODS: This is a prospective study that was conducted at Shiraz University of Medical Sciences in southern Iran from March 2011 to June 2014. Consecutive patients undergoing CAS were enrolled. Both standard- and high-risk patients for endarterectomy were enrolled. Demographic data, atherosclerotic risk factors, site of stenosis, degree of stenosis, and data regarding technical factors were recorded. Thirty-day stroke, myocardial infarction, and/or death were considered as the composite primary outcomes of the study. RESULTS: A total of 251 patients were recruited (mean age: 71.1 ± 9.6 years; male: 65.3%). Of these, 178 (70.9%) were symptomatic, 73 (29.1%) were diabetic, 129 (51.4%) were hyperlipidemic, 165 (65.7%) were hypertensive, and 62 (24.7%) patients were smokers. CAS was performed for left internal carotid artery (ICA) in 113 (45.4%) patients. Fourteen (5.6%) patients had sequential bilateral stenting. Mean stenosis of operated ICA was 80.2 ± 13.8%. An embolic protection device was used in 203 (96.2%) patients. Pre- and postdilation were performed in 39 (18.5%) and 182 (86.3%) patients, respectively. Composite outcomes were observed in 3.6% of patients (3.2% stroke, 0% myocardial infarction, and 1.2% death). Left-sided lesions and the presence of diabetes mellitus were significantly associated with poor short-term outcome (p = 0.025 and p = 0.020, respectively). CONCLUSION: There was a higher risk of short-term major complications in diabetic patients and for left carotid artery intervention.

Large-vessel stenosis in the patients with ischemic stroke in Iran: Prevalence, pattern, and risk factors.

BACKGROUND: Large artery disease (LAD) is a common cause of stroke, but a little is known regarding its role in Iranian stroke patients. The current study investigates the prevalence and risk factors for cervicocephalic arterial stenosis in the patients with ischemic stroke using digital subtraction angiography (DSA). METHODS: This was a prospective cross-sectional study performed in hospitals affiliated to Shiraz University of Medical Sciences from March 2011 to March 2013. Patients with ischemic stroke underwent noninvasive vascular and cardiac investigations to find the etiology of the stroke. Patients suspected of having large artery stenosis underwent DSA. The severity of the stenosis was calculated according to the North American Symptomatic Carotid Endarterectomy (NASCET) and Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) Trial criteria. The presence of cigarette smoking, hyperlipidemia, hypertension, and diabetes mellitus were documented for all subjects. RESULTS: A total of 3703 stroke patients were identified. Of them, 342 patients (62.3%, male) underwent DSA for LAD. The mean age at the time of angiography was 66.7±10.3 years. Extracranial and intracranial arteries were involved in 305 (89.2%) and 162 (47.4%), respectively. And 301 patients (88%) had anterior circulation and 128 patients (37.4%) had posterior circulation involvement. Diabetes mellitus but not age, sex, hypertension, hyperlipidemia, or smoking was significantly associated with intracranial involvement. (P = 0.002). CONCLUSION: It can be concluded that the distribution of the large arterial atherosclerotic disease in Iran is similar to that seen in North America and Europe. Intracranial stenosis was more prevalent in diabetic patients.