Ultrasound-Assist Extrusion Methods for the Fabrication of Polymer Nanocomposites Based on Polypropylene/Multi-Wall Carbon Nanotubes

Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 10¹³ to 10⁵ Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods.     

Prospective multicenter clinical trial of Uretex Sup for surgical treatment of stress urinary incontinence

AIM: To evaluate in a prospective multicenter study the efficacy and safety of the suburethral support Uretex (Sofradim, Trevoux, France) delivered by a suprapubic approach in the treatment of female stress urinary incontinence. METHODS: Between March 2002 and March 2003, 57 patients were treated for stress urinary incontinence with Uretex. Preoperative evaluation included urodynamic examination and questionnaires (symptoms and quality of life, Contilife). Forty patients had pure stress urinary incontinence and 17 mixed urinary incontinence. No associated procedure was performed. The objective cure rate was evaluated by clinical examination and pad-test, and the subjective cure rate was assessed through questionnaires at 1, 3 and 12 months. RESULTS: The mean follow-up was 13 months (range 11-24 months). During follow up, chronic urinary retention requiring a tape section occurred in one patient, and in another patient a delay of vaginal healing was followed by a sling exposure and resection at 4 months. No infection or urethral erosion was reported. The objective cure rate was 96.2%, and the subjective cure rate was 79.2%; four patients reported low leakage on stress and nine patients complained of urge incontinence (four de novo and five persistent). CONCLUSION: The suprapubic Uretex Sup procedure is a safe and effective treatment for women with stress urinary incontinence.     

单丝聚丙烯合成非吸收齿状线在美容整形应用中并发症的防治及应用改进

目的探讨单丝聚丙烯合成非吸收齿状线在美容整形中的并发症产生的原因及应用方法及技术的改进。方法对近两年的单丝聚丙烯合成非吸收齿状线在美容整形中的应用进行总结与分析。结果改进应用方法后，并发症明显减少，效果加强。结论单丝聚丙烯合成非吸收齿状线在美容整形中应用得当，可减少并发症、取得显著效果。     

Silicone-Coated Polypropylene Hollow-Fiber Oxygenator: Experimental Evaluation and Preliminary Clinical Use

Background. A membrane oxygenator consisting of a microporous polypropylene hollow fiber with a 0.2-μm ultrathin silicone layer (cyclosiloxane) was developed. Animal experimental and preliminary clinical studies evaluated its reliability in bypass procedures.

Methods. Five 24-hour venoarterial bypass periods were conducted on dogs using the oxygenator (group A). In 5 controls, bypass periods were conducted using the same oxygenator without silicone coating (group B). As a preliminary clinical study, 14 patients underwent cardiopulmonary bypass with the silicone-coated oxygenator.

Results. Eight to 16 hours (mean, 12.2 hours) after initiation of bypass, plasma leakage occurred in all group B animals, but none in group A. The O₂ and CO₂ transfer rates after 24 hours in group A were significantly higher than at termination of bypass in group B (p < 0.005 and p < 0.03, respectively). Scanning electron microscopy of silicone-coated fibers after 24 hours of bypass revealed no damage to the silicone coating of the polypropylene hollow fibers. In the clinical study, the oxygenator showed good gas transfer, acceptable pressure loss, low hemolysis, and good durability.

Conclusions. This oxygenator is more durable and offers greater gas transfer capabilities than the previous generation of oxygenators.     

应力场下固—液相分离制备微孔聚丙烯中空纤维膜

将聚丙烯和石蜡油的混合物熔融挤出,使之在较高的应力场下冷却和相分离,得到了弹性聚丙烯中空纤维。这种部分结晶的弹性纤维可能具有平行排列的片晶结构,石蜡油存在于片晶之间。将石蜡油提取掉后稍加拉伸即可得到透气性很好的微孔中空纤维渗透膜。     

动态硫化PP／EPDM强化增韧机理的动态力学研究

采用动态力学试验方法,研究了不同ＥＰＤＭ含量的动态硫化和简单共混两种ＰＰ／ＥＰＤＭ材料动态力学响应的差异及其特征。结果显示：与简单共混ＰＰ／ＥＰＤＭ相比,动态硫化ＰＰ／ＥＰＤＭ具有ΔＴｇ小,内耗峰扩宽程度大,低温和室温内耗峰强度高,所处温度低,６０－７０℃时内耗峰强度发生高低变位,在ＥＰＤＭ相的α转变以下还显示β和γ次级转变等特性。     

Compatibility and stability of bryostatin 1 in infusion devices

Bryostatin 1 is currently in phase II clinical trial sponsored by the National Cancer Institute as an anticancer chemotherapeutic agent. Bryostatin 1 for injection was supplied in a dual pack containing a drug vial and a diluent vial and was manufactured by Ben Venue Laboratories, Inc (Bedford, OH). The stability and compatibility of the bryostatin 1-PET formulation, diluted to 1 and 10 ug/mL in saline and benzyl alcohol preserved saline, with polypropylene (PP) and polyvinyl chloride (PVC) bags at room temperature (27°C) were studied. All experiments were conducted in triplicate and analyses were performed using a validated, stability-indicating, high performance liquid chromatography (HPLC) assay.Bryostatin 1 solutions were compatible with PP bags. At both concentrations and with both salines, the bryostatin content remained unchanged during the 28-day storage period, benzyl alcohol concentration in the preserved saline solutions also remained relatively constant. In PVC bags, however, a decrease in bryostatin 1 concentrations without generation of decomposition products was observed at both dilutions and with both salines during the 28-day storage. A decrease in benzyl alcohol concentration in the preserved saline was also observed. While no diethylhexylphthalate (DEHP) leakage into the solution was observed in PP bags, DEHP leakage in PVC infusion bags was observed on day 2 of storage which increased with storage time and leveled off on day 6. The amount of DEHP leached into drug solution is dependent on the drug concentration. This study suggests bryostatin-PET formulation diluted with preserved saline can be used for long-term (4 week) intravenous administration using PP infusion bags, but not with PVC bags.     

Influence of a New Monofilament Polyester Mesh on Inflammation and Matrix Remodeling

ABSTRACT

Synthetic mesh is widely used for hernia repairs, but mesh-induced chronic inflammatory responses may lead to postoperative complications. We previously showed an elevated response to multifilament polyester (PE) versus monofilament polypropylene (PP) and polytetrafluoroethylene (PTFE) meshes, but it is unclear whether this discrepancy is due to the differences in chemical composition or filament structure. This study compares the influence of a newly available monofilament PE mesh to that of multifilament PE, monofilament PP, and monofilament PTFE on the expression of genes important in inflammation and extracellular matrix remodeling in a rat model. Full thickness abdominal wall defects were corrected with onlay repair or suture repair with no mesh. Explants were harvested 7 or 90 days after repair and divided for histology and mRNA analyses using real-time quantitative polymerase chain reaction arrays to profile expression at the tissue-mesh interface. Monofilament PE elicited a reduced foreign body reaction compared to multifilament PE, corresponding with reduced mRNA expression of important inflammatory cytokines and matrix metalloproteinases (MMPs). Unexpectedly, monofilament PE also resulted in markedly reduced mRNA expression of tumor necrosis factor and MMPs 3 and 9 compared to the widely-used monofilament PP mesh. Findings from this study revealed that both chemical composition and filament structure are important mesh characteristics that may affect a patient's wound healing response and clinical outcome, and should be considered by the surgeon when choosing a particular mesh. Although clinical studies are warranted, results in a rodent model suggest that monofilament PE may be more beneficial than the multifilament form for certain hernia repairs.     

Early Necrectomy in Deep Burns of Aesthetically and Functionally Important Areas

Deep burns of aesthetically and functionally important body areas in children may in their later growth and development have a decisive role. Of the total number (2743) of hospitalized children at the Burns Department of the Pediatric Surgery in Zagreb in the last ten years. deep burns of some aesthetically and functionally important body areas were separated and the results of the application of the early necrectomy and immediate grafting method, as recommended by Jan?ekovi?, are analysed. It is concluded that the results, due to the strict and minute application of the method (considered are individual technically important details and solutions) are good in aesthetic and even more so in the functional sense. Very fast recovery of the functions as well as the fact that up till now no surgical corrections for functional disorders were necessary in analyzed areas, along with already known advantages of the early surgical treatment, undoubtfully speak for its application.     

Safety assessment for octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (CAS Reg. No. 2082-79-3) from use in food contact applications

Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (CAS Reg. No. 2082-79-3), currently marketed as Irganox 1076 (I-76), is a sterically hindered phenolic antioxidant used in a variety of organic substrates, including those used in the manufacture of food contact articles. In 2012, the US Food and Drug Administration (USFDA), Office of Food Additive Safety (OFAS), initiated a post-market re-evaluation of the food contact applications of I-76. This project aimed to ensure that current dietary exposures from the use of I-76 in food contact articles are accurately captured and the safety assessment considered all relevant and available toxicological information. To accomplish these aims, the USFDA reviewed the available toxicological studies and chemistry information on food contact applications of I-76. Based on this in-depth analysis, a NOAEL of 64 mg/kg-bw/d (female rats) from a chronic rat study and a cumulative estimated dietary intake (CEDI) of 4.5 mg/p/d, was used to calculate a margin of exposure (MOE) of ∼850. We concluded that the previous and current exposure levels provide an adequate margin of safety (MOS) and remain protective of human health for the regulated uses.