Processing, Adhesion and Corrosion-inhibiting Properties of Poly[2-methoxy-5-(2’-ethylhexyloxy)-1,4-phenylene vinylene], (MEH-PPV) on Aerospace Aluminum Alloys

Researchers at the Naval Air Warfare Center Weapons Division (NAWCWD) and Wright-Patterson Air Force Base (WPAFB) investigated poly[2-methoxy-5-(2’-ethylhexyloxy)-1,4-phenylene vinylene], (MEH-PPV) for its potential corrosion-inhibition properties on aerospace aluminum alloy AA2024-T3. Solution processing of the polymer, as well as adhesion testing and accelerated weathering tests were performed on MEH-PPV full military aerospace coatings. Wet and dry tape adhesion testing, as well as pencil hardness, impact flexibility and pneumatic adhesion tensile test instrument (PATTI) testing were used to demonstrate the adhesion performance of MEH-PPV on aluminum substrates. The results showed that MEH-PPV had acceptable adhesion characteristics when compared to hexavalent chromium (Cr(VI)) based coatings in all of these tests. Accelerated weathering analysis was performed on MEH-PPV coatings to determine their corrosion protection and weathering resistance capabilities. These tests included neutral salt spray (NSS) exposure and xenon-arc lamp testing. The results showed that while MEH-PPV does not exhibit significant color change after 500 hours of xenon arc lamp exposure, the polymer has poor corrosion protection performance under aggressive salt environments

Poly(2,5-bis(N-Methyl-N-Hexylamino)Phenylene Vinylene) (BAM-PPV) as Pretreatment Coating for Aerospace Applications: Laboratory and Field Studies

In this study, an electroactive polymer (EAP), poly(2,5-bis(N-methyl-N-hexylamino)phenylene vinylene) (BAM-PPV) was investigated as a potential alternative surface pretreatment for hexavalent chromium (Cr(VI))-based aerospace coatings. BAM-PPV was tested as a pretreatment coating on an aerospace aluminum alloy (AA2024-T3) substrate in combination with a non-Cr(VI) epoxy primer and a polyurethane Advanced Performance Coating (APC) topcoat. This testing was undertaken to determine BAM-PPV’s adhesion, corrosion-inhibition, compatibility and survivability in laboratory testing and during outdoor field-testing. BAM-PPV showed excellent adhesion and acceptable corrosion performance in laboratory testing. The BAM-PPV aerospace coating system (BAM-PPV, non-Cr(VI) epoxy primer and polyurethane APC topcoat) was field tested for one year on the rear hatch door of the United States Air Force C-5 cargo plane. After one year of field testing there was no evidence of delamination or corrosion of the BAM-PPV aerospace coating system

Stapler-assisted stoma prolapse repair with real-time fluorescent angiography using indocyanine green

<jats:title>Abstract</jats:title><jats:p>Stoma prolapse is an increase in the size of the stoma secondary to intussusception of the proximal bowel segment. Transverse loop colostomy is most commonly involved. Although ostomy function is rarely impaired, large prolapses may cause patients distress and impair stoma dressing. Strangulation and ischemia of the prolapsed segment have been reported as complications. Herein, we report a stapler-associated repair of a prolapsed transverse loop colostomy with real-time perfusion studies using indocyanine green.</jats:p&gt

The role of indocyanine green fluoroscopy for intraoperative bile duct visualization during laparoscopic cholecystectomy: an observational cohort study in 70 patients

Abstract Background Bile duct injury is the most feared complication during laparoscopic cholecystectomy. Real-time intraoperative imaging using indocyanine green (ICG) might reduce the risk of bile duct injury by improving visualization of the biliary tree during laparoscopic cholecystectomy. We compared the outcomes of laparoscopic cholecystectomy in patients with and without real-time ICG. Methods A retrospective analysis of the data of patients undergoing laparoscopic cholecystectomy with and without ICG in a referral centre for minimally invasive surgery was performed. We hypothesized that laparoscopic cholecystectomy with real-time ICG enables a better identification of the biliary tree and thus increases surgical safety. The outcomes of laparoscopic cholecystectomy with and without ICG were compared using the duration of surgery, the rate of bile duct injury, the rate of conversion, complications and the length of stay. Results Seventy patients including 29 with and 41 without ICG underwent laparoscopic cholecystectomy within the period of investigation. The median duration of surgery was 53.0 vs. 54.0 min while the median length of stay was 2.0 d in the group with and without ICG respectively. The rate of conversion was 2.4% in the group without ICG, while no conversion was performed in the group with ICG. NO bile duct injury occurred in both groups. These differences were not statistically significant. Conclusion Laparoscopic cholecystectomy with real-time indocyanine green fluorescence cholangiography enables a better visualization and identification of biliary tree and therefore should be considered as a means of increasing the safety of laparoscopic cholecystectomy

Laboratory and Field Studies of Poly(2,5-bis(N-methyl-N-hexylamino)phenylene vinylene) (BAM-PPV): A Potential Wash Primer Replacement for Army Military Vehicles

In this study, an electroactive polymer (EAP), poly(2,5-bis(N-methyl-N- hexylamino)phenylene vinylene) (BAM-PPV), was tested as an alternative to current hexavalent chromium (Cr(VI))-based Army wash primers. BAM-PPV was tested in both laboratory and field studies to determine its adhesive and corrosion-inhibiting properties when applied to steel and aluminum alloys. The Army Research Laboratory (ARL) tests showed that BAM-PPV combined with an epoxy primer and the Army chemical agent-resistant coating (CARC) topcoat met Army performance requirements for military coatings. After successful laboratory testing, the BAM-PPV was then field tested for one year at the Aberdeen Test Center (ATC). This field testing showed that BAM-PPV incorporated into the Army military coating survived with no delamination of the coating and only minor corrosion on the chip sites

Routine preoperative mechanical bowel preparation with additive oral antibiotics is associated with a reduced risk of anastomotic leakage in patients undergoing elective oncologic resection for colorectal cancer

Abstract Background Anastomotic leakage (AL) following colorectal resection is a serious issue. AL in oncologic patients might negatively affect the overall survival. Recently, mechanical bowel preparation with additive oral antibiotics (MBP + AB) prior to surgery has been suggested as a means of reducing AL. However, it is unclear whether this positive effect is secondary to MBP alone or secondary to the additive oral antibiotic (MBP + AB). The aim of this study was to investigate the effect of mechanical bowel preparation with additive oral antibiotics (MBP + AB) and without additive oral antibiotics (MBP − AB) on the rate of AL following colorectal resection for cancer. Materials and methods Patients undergoing surgical management for colorectal cancer with anastomosis from January 2014 till September 2017 were included for analysis. Cases undergoing MBP + AB were included in the study group. Patients undergoing MBP − AB were included in the control group. Both groups were compared with regard to the rate of AL. Results Four hundred and ninety-six patients: 125 undergoing MBP + AB and 371 undergoing MBP – AB were included for analysis. Significantly, more male patients were included in the MBP – AB group compared to the MBP + AB group: 60.1% vs. 45.6% respectively (p = 0.03). Both groups were similar with regard to age distribution and clinicopathological findings (p > 0.05). The rate of AL was significantly higher in the control group (MBP − AB) compared to study group (MBP + AB) (9.1% vs. 4.0%, p = 0.03). Conclusion Mechanical bowel preparation with additive oral antibiotics prior to elective colorectal resection with anastomosis significantly reduces the risk of AL. Therefore, mechanical bowel preparation with additive non-absorbable oral antibiotics should be recommended in all cases prior to elective colorectal surgery

Intraoperative real-time fluorescence angiography with indocyanine green for evaluation of intestinal viability during surgery for an incarcerated obturator hernia: a case report

Abstract Background Bowel incarceration represents a dreaded complication amongst patients with hernias. The intraoperative evaluation of the bowel perfusion following hernia reduction with regard to the need for resection of ischaemic bowel can be challenging. In this case report we discuss intraoperative fluorescence angiography with indocyanine green (ICG) as an objective means of accessing bowel perfusion following hernia reduction. Case presentation The case of a 92-year-old, caucasian, female patient presenting with symptoms of small bowel obstruction secondary to an incarcerated left sided obturator hernia is presented. An incarcerated segment of the small bowel was reduced during emergency laparoscopy. Intraoperative ICG fluorescence angiography revealed ischaemic changes in the normal appearing bowel, so that the involved segment was resected. The postoperative course was uneventful and the patient was discharged home safely on postoperative day seven. Conclusion Intraoperative ICG fluorescence angiography provides an objective method of judging bowel perfusion and therefore represents a useful tool for assessing intestinal perfusion in patients with incarcerated hernia

Waterborne functional paints to control biodeteration

Coatings are generally defined as any material (usually liquid) that may be applied as a thin continuous layer to a surface. Paint is a term traditionally used to describe a specific dispersion system constituted by pigments, binder(s) (polymer or resin), solvents, and additives. These pigmented systems are designed for application to a substrate as a thin layer which is converted to an opaque solid film after application unlike of lacquers or varnishes. Therefore, paint is any pigmented coating. Coatings are usually applied as multilayered systems, each layer performing a specific function. Mostly these systems are used for decorative and protective purposes, but depending on the surface to cover and the environmental conditions in service, additional properties are required. Examples of these films with additional functionalities, known as functional coatings, are self-cleaning, easy-to-clean (antigraffiti), self-healing, anticorrosive, hygienic, and antifouling.Centro de Investigación y Desarrollo en Tecnología de PinturasConsejo Nacional de Investigaciones Científicas y Técnica