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Plastics have brought invaluable convenience to human life since it was firstly synthesized in the last century. However, the stable polymer structure of plastics led to the continuous accumulation of plastic wastes, which poses serious threats to the ecological environment and human health. Poly(ethylene terephthalate) (PET) is the most widely produced polyester plastics. Recent researches on PET hydrolases have shown great potential of enzymatic degradation and recycling of plastics. Meanwhile, the biodegradation pathway of PET has become a reference model for the biodegradation of other plastics. This review summarizes the sources of PET hydrolases and their degradation capacity, degradation mechanism of PET by the most representative PET hydrolase-IsPETase, and recently reported highly efficient degrading enzymes through enzyme engineering. The advances of PET hydrolases may facilitate the research on the degradation mechanism of PET and further exploration and engineering of efficient PET degradation enzymes.
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Humans , Hydrolases/metabolism , Polyethylene Terephthalates/metabolism , Plastics/metabolism , EthylenesABSTRACT
Objective To compare and analyze the advantages and disadvantages of the application of self-fixing and plain polypropylene mesh in open inguinal hernia repair.Methods A study of 83 patients who underwent open inguinal hernia repair patients from June 2014 to June 2016 in the Department of General Surgery,AnHui No.2 Provincial People's Hospital Patients were divided into two groups according to the use of different patches,42 cases were applicated self-fixating mesh (observation group) and 41 cases were applicated the ordinary polypropylene patch (control group).The operation time,average postoperative hospitalization time,postoperative complications and Visual Analogue Score of postoperative pain were compared.The measurement data were expressed by mean standard deviation (~ ± s),and using t test,Count data were represented by frequency and percentage,and chi-square test was used for comparison between groups.Results The operation time of the observation group and the control group was (49.9 ± 6.4) minutes and (67.9 ± 6.1) minutes,and there was significant difference(P ＜ 0.05).The postoperative hospitalization time of observation group and control group was (2.5 ± 1.4) days and (2.6 ± 1.8) days,there was no significant difference (P ＞ 0.05).In the complications of the two groups,there were 1 case of scrotal edema in the observation group,and 2 cases of scrotal edema in the control group,the difference was no statistically significance.The Visual Analogue Score in two groups was (4.0 ± 0.8) score and (4.1 ± 0.7) score,there was no significant difference between the two groups (P ＞ 0.05) within 12 hours after operation.The Visual Analogue Score was (2.6 ± 0.7) score,(1.4 ± 0.5) score within 24 hours and 48 hours after operation in the observation group,and was (3.1 ± 0.6) score,(2.7 ± 0.5) score in the control group.There was a significant difference between the two groups (P ＜ 0.05).There was no obvious local pain for the observation group and had a better sense of comfort in one month follow-up after the operation.Conclusions The application of self-fixing suture free patch can reduce the operation time of patients and relieve the discomfort of postoperative pain,and has a high clinical value.
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Objective To investigate the effect of early enteral nutrition.Methods 248 patients with esophageal and gastric carcinoma were randomly divided into two groups,and received enteral nutrition(EN)and parenteral nutrition(PN)each continuously for 6 days after operation.The body weight,blood routine test,liver function,and postoperative day 8 were compared with those before operation.Results The body weight,red blood cell count,and the levels of hemoglobin,serum albumin and transaminase decreased less in EN group than those in PN group(P＜0.01).The complication rates of anastomotic fistula,pulmonary infection,and delayedincision healing and average volume of pleural effusion were 0,13.8%,0,780ml in EN groups,while 3.2%,28.2%,7.2%,1842ml in PN group.Conclusion Early postoperative enteral nutirtion after esophageal carcinoma surgery can improve nutritional status and reduce complications in comparision with parenteral nutrition.
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BACKGROUND: Many study results proved that electroacupuncture can cause change of endogenous opioid peptide system.OBJECTIVE: To observe the change of blood sugar and blood lipoprotein (a) in rats with diabetes mellitus after electroacupuncture therapy and probe into the effect of opioid peptide system in the treatment for diabetes with electroacupuncture.DESIGN: Randomized controlled trial with experimental animals as the subjects.SETTING: The experiment was conducted in the Department of Pathophysiology, Medical College of Shandong University.MATERIALS: The experiment was completed in the Department of Pathophysiology, Medical College of Shandong University from July 2004 to December 2004. Totally 140 male Wistar rats were involved.METHODS: Ten Wistar rats were collected randomly as the blank control group. The other 130 rats were given 20 g/L streptozotocin 50 mg/kg intraperitoneally and the rats in blank control group were given the same volume of saline intraperitoneally. Three weeks later, the tails were cut off and the blood sugar was measured 2 hours after food intake. The rats with obvious rapid sugar tolerance were given foods with high calories for 28 days as the model rats. There were 64 rats were successful models and they were classified into 3 groups randomly, namely model control group( n = 20), electroacupuncture therapy(n=22) and electroacupuncture with naloxone groups( n = 22) . The blood sugar and blood lipoprotein(a) were detected after treatment for the diabetic rats with streptozotocin.MAIN OUTCOME MEASURES: Blood sugar level and blood lipoprotein(a) of each rat after the final therapy.RESULTS: Totally 74 rats entered the result analysis. Electroacupuncture therapy could reduce the blood sugar and blood lipoprotein(a) of diabetes mellitus rats, while rats with naloxone injection before therapy were insensitive to electroacupuncture. [The blood sugar value were(13.91 ± 3.79),( 10.33 ± 2.36), (12.96 ± 2.23)mmol/L in the model control group, electroacupuncture therapy group, electroacupuncture with naloxone group respectively; while the level of blood lipoprotein(a) were(13.75 ±2.69),( 10.81 ± 2.96), (13.01 ± 3.23)mg/L respectively].CONCLUSION: Electroacupuncture therapy can reduce the level of blood sugar and the risk of atherosclerosis in rats with diabetes mellitus. Although the mechanism can not be explained through the meridian theory, according to the experimental result that blood sugar and blood lipoprotein(a) were no longer intervened by electroacupuncture therapy after injecting naloxone, it is presumed that electroacupuncture therapy can exert its intervention effect on blood sugar and blood lipoprotein(a)through opiate system.
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0 05). Positive expression rates of Fas and bcl-2 were 60 0% and 92 9% respectively and Fas increased along with the escalation of the pathological grading (?=0 584,P0 05). Conclusions DNA ploidy aberration,Fas and bcl-2 overexpression could play an important role in the development of esophageal carcinoma .