Design and Performance of Novel Self-Cleaning g-C3N4/PMMA/PUR Membranes

In the majority of photocatalytic applications, the photocatalyst is dispersed as a suspension of nanoparticles. The suspension provides a higher surface for the photocatalytic reaction in respect to immobilized photocatalysts. However, this implies that recovery of the particles by filtration or centrifugation is needed to collect and regenerate the photocatalyst. This complicates the regeneration process and, at the same time, leads to material loss and potential toxicity. In this work, a new nanofibrous membrane, g-C3N4/PMMA/PUR, was prepared by the fixation of exfoliated g-C3N4 to polyurethane nanofibers using thin layers of poly(methyl methacrylate) (PMMA). The optimal amount of PMMA was determined by measuring the adsorption and photocatalytic properties of g-C3N4/PMMA/PUR membranes (with a different PMMA content) in an aqueous solution of methylene blue. It was found that the prepared membranes were able to effectively adsorb and decompose methylene blue. On top of that, the membranes evinced a self-cleaning behavior, showing no coloration on their surfaces after contact with methylene blue, unlike in the case of unmodified fabric. After further treatment with H2O2, no decrease in photocatalytic activity was observed, indicating that the prepared membrane can also be easily regenerated. This study promises possibilities for the production of photocatalytic membranes and fabrics for both chemical and biological contaminant control.

The Prevalence of Bacterial Infection in Patients Undergoing Elective ACDF for Degenerative Cervical Spine Conditions: A Prospective Cohort Study With Contaminant Control

Study Design: Prospective cohort study. Objectives: To determine the prevalence of bacterial infection, with the use of a contaminant control, in patients undergoing anterior cervical discectomy and fusion (ACDF). Methods: After institutional review board approval, patients undergoing elective ACDF were prospectively enrolled. Samples of the longus colli muscle and disc tissue were obtained. The tissue was then homogenized, gram stained, and cultured in both aerobic and anaerobic medium. Patients were classified into 4 groups depending on culture results. Demographic, preoperative, and postoperative factors were evaluated. Results: Ninety-six patients were enrolled, 41.7% were males with an average age of 54 ± 11 years and a body mass index of 29.7 ± 5.9 kg/m2. Seventeen patients (17.7%) were considered true positives, having a negative control and positive disc culture. Otherwise, no significant differences in culture positivity was found between groups of patients. However, our results show that patients were more likely to have both control and disc negative than being a true positive (odds ratio = 6.2, 95% confidence interval = 2.5-14.6). Propionibacterium acnes was the most commonly identified bacteria. Two patients with disc positive cultures returned to the operating room secondary to pseudarthrosis; however, age, body mass index, prior spine surgery or injection, postoperative infection, and reoperations were not associated with culture results. Conclusion: In our cohort, the prevalence of subclinical bacterial infection in patients undergoing ACDF was 17.7%. While our rates exclude patients with positive contaminant control, the possibility of contamination of disc cultures could not be entirely rejected. Overall, culture results did not have any influence on postoperative outcomes.