Abiotic and biotic environmental degradation of the bioplastic polymer poly(lactic acid): A review

© 2017 Elsevier LtdPoly(lactic acid) (PLA) is a compostable bioplastic manufactured by the polymerization of lactic acid monomers derived from the fermentation of starch as a feedstock. Since its first commercialisation in the late 1990's, PLA production has grown annually and currently it estimated that worldwide production will reach at least 800,000 tons by 2020 with Japan and the USA the two major producers. PLA is used as a replacement to conventional petrochemical based plastics, principally as food packaging containers and films and more recently, in electronics and in the manufacture of synthetic fibres. Consequently, there has been a marked increase in PLA contamination in the environment as well as increasing amounts being diverted to commercial composting facilities. This review focuses on the development, production, stability and degradation of PLA in a range of differing environments and explores our current knowledge of the environmental and biological factors involved in PLA degradation

The Compostable Plastic Poly(lactic) Acid Causes a Temporal Shift in Fungal Communities in Maturing Compost

The compostable biopolymer, poly(lactic) acid (PLA), is increasingly being used as an alternative to conventional plastics for short shelf-life products, disposable bags and packaging, and in agriculture. Despite the increase in the amount of PLA entering composting systems, few studies have examined the impact of PLA degradation on the compost microbial community. Thermophilic fungi play an import role in the composting process as they secrete hydrolytic enzymes capable of breaking down an array of complex natural polymers. In this study, the impact of PLA hydrolysis on the compost fungal community was examined by terminal restriction fragment length polymorphism and 454 sequencing. At 25°C, the effect of PLA on the surrounding compost community was relatively small and no physical changes were observed to the PLA films. However, when incubated at 50°C, where physical disintegration of PLA was occurring, a clear divergence between the compost populations in the presence and absence of PLA was evident after 2 months but became closer to the population in the absence of PLA after 4 months indicating that, after causing an initial perturbation after 2 months, the population began to return to that seen in the absence of PLA. The only exception was in the population containing 50% (w/w) PLA film, which remained divergent after 4 months and was associated with a marked acidification of the compost. Thus, 454-pyrosequencing revealed that the presence of PLA caused a strong selection for a Thermomyces sp. that was present only at low abundance in the absence of PLA

Etoricoxib - preemptive and postoperative analgesia (EPPA) in patients with laparotomy or thoracotomy - design and protocols

<p>Abstract</p> <p>Background and Objective</p> <p>Our objective was to report on the design and essentials of the <it>Etoricoxib </it>protocol<it>- Preemptive and Postoperative Analgesia (EPPA) </it>Trial, investigating whether preemptive analgesia with cox-2 inhibitors is more efficacious than placebo in patients who receive either laparotomy or thoracotomy.</p> <p>Design and Methods</p> <p>The study is a 2 × 2 factorial armed, double blinded, bicentric, randomised placebo-controlled trial comparing (a) etoricoxib and (b) placebo in a pre- and postoperative setting. The total observation period is 6 months. According to a power analysis, 120 patients scheduled for abdominal or thoracic surgery will randomly be allocated to either the preemptive or the postoperative treatment group. These two groups are each divided into two arms. Preemptive group patients receive etoricoxib prior to surgery and either etoricoxib again or placebo postoperatively. Postoperative group patients receive placebo prior to surgery and either placebo again or etoricoxib after surgery (2 × 2 factorial study design). The Main Outcome Measure is the cumulative use of morphine within the first 48 hours after surgery (measured by patient controlled analgesia PCA). Secondary outcome parameters include a broad range of tests including sensoric perception and genetic polymorphisms.</p> <p>Discussion</p> <p>The results of this study will provide information on the analgesic effectiveness of etoricoxib in preemptive analgesia and will give hints on possible preventive effects of persistent pain.</p> <p>Trial registration</p> <p>NCT00716833</p

The impact of the extent and severity of coronary artery disease on fractional flow reserve measurements

WOS: 000384168600016PubMed: 27608903OBJECTIVE: Coronary angiography has a limitation to determine the severity of intermediate stenosis (30-70%)(1,2). Fractional flow reserve (FFR) is a method for the assessment of the intermediate stenosis severity(3). The effect of coronary artery disease (CAD) severity on the FFR results is not clear. In this study, we aimed to expose the effect of CAD severity calculated with Syntax and Gensini scores on FFR results. PATIENTS AND METHODS: We scanned patients data (n= 378) who had undergone fractional flow reserve measurements in our center. Patients with acute coronary syndrome in the last month, moderate or severe valvular diseases, acute heart failure, serious bradycardia, atrial fibrillation/flutter, severe left ventricular hypertrophy or patient with deficient data were excluded. 351 patients were included in the study. Syntax and Gensini scores were calculated and compared with FFR results. Hemodynamically significant result for FFR, ratio 22 had notable more crucial lesions in FFR measurements (p<0.001). Cardiovascular disease risk factors such as age, gender, hypertension, diabetes mellitus and dyslipidemia did not correlate with the FFR results. Patients with intermediate stenosis (30-70%) and high Gensini and high Syntax scores were found to have more hemodynamically significant on FFR measurements (FFR < 0.80). CONCLUSIONS: Intermediate lesions with high Syntax score should be evaluated by hemodynamic procedures and treated more carefully with optimal medical treatment or revascularization. Revascularization method of CAD with high Syntax score should be decided with hemodynamic procedures as FFR measurements

Comparison of the efficacy of colistin monotherapy and colistin combination therapies in the treatment of nosocomial pneumonia and ventilator-associated pneumonia caused by Acinetobacter baumannii

Objective. To investigate whether there was a difference in mortality, clinical response and bacterial eradication between colistin monotherapy and colistin combination therapies for the treatment of nosocomial pneumonia/ventilator-associated pneumonia (VAP) caused by Acinetobacter baumannii in a medical intensive care unit (ICU). Methods. This retrospective, observational and single-centre study included all patients who were in the medical ICU of Gazi University Medical Faculty Hospital and diagnosed with nosocomial pneumonia/VAP caused by A. baumannii between January 2009 and September 2014. Results. The median age of the 134 patients was 68 years and 53.3% were male. The most common causes of admission were respiratory insufficiency (66.7%) and sepsis/septic shock (54.8%). In patients with nosocomial pneumonia/VAP caused by A. baumannii, on median day 5 of admission, colistin monotherapy was used in 23 (21.6%) patients, a carbapenem combination was used in 80 (59.7%) patients, sulbactam-ampicillin combination was used in 42 (31.4%) patients, tigecycline combination was used in 26 (19.4%) patients, and sulbactam-cefoperazone combination was used in 17 (12.7%) patients. Median ICU stay of the patients was 15.5 days, and 112 (83.6%) patients died. Colistin monotherapy and combination therapies had no superiority over each other in clinical response for the treatment of A. baumannii-associated nosocomial pneumonia/VAP. Mortality was found to be higher in patients receiving the colistin-carbapenem combination (64.3% v. 36.4%, p=0.016). Discharge/day-of-death Sequential Organ Failure Assessment score (odds ratio (OR) 2.017, 95% confidence interval (CI) 1.330 - 3.061) and vasopressor use (OR 9.014, 95% CI 1.360 - 59.464) were independent risk factors for ICU mortality.Conclusion. Colistin monotherapy and combination therapies have no superiority over each other for clinical response in the treatment of nosocomial pneumonia/VAP caused by multidrug-resistant A. baumannii. Colistin-SAM was associated with improved microbiological eradication and colistin-carbapenem combination was associated with increased mortality