Surface modification of nanofiltration membranes to improve the removal of organic micropollutants: Linking membrane characteristics to solute transmission.

Surface modification of nanofiltration (NF) membranes has great potential to improve the removal of organic micropollutants (OMs) by NF membranes. This study used polydopamine (PDA) as a model coating to comprehensively link the changes in membrane properties with the changes in transmission of 34 OMs. The membrane characterization demonstrated that a thicker, denser, and more hydrophilic PDA coating can be achieved by increasing the PDA deposition time from 0.5 to 4 hours. Overall, the transmissions of target OMs were reduced by PDA-coated NF membranes compared to unmodified NF membranes. The neutral hydrophobic compounds showed lower transmissions for longer PDA coating (PDA4), while the neutral hydrophilic compounds tended to show lower transmissions for shorter PDA coating (PDA0.5). To explain this, competing effects provided by the PDA coatings are proposed including sealing defects, inducing cake-enhanced concentration polarization in the coating layer for neutral hydrophilic compounds, and weakened hydrophobic adsorption for neutral hydrophobic compounds. For charged compounds, PDA4 with the greatest negative charge among the PDA-coated membranes showed the lowest transmission. Depending on the molecular size and hydrophilicity of the compounds, the transmission of OMs by the PDA4 coating could be reduced by 70% with only a 26.4% decline in water permeance. The correlations and mechanistic insights provided by this work are highly useful for designing membranes with specific surface properties via surface modification to improve the removal of OMs without compromising water production.

Polymerization-Induced Phase Segregation and Self-Assembly of Siloxane Additives to Provide Thermoset Coatings with a Defined Surface Topology and Biocidal and Self-Cleaning Properties.

In this work, we report on the incorporation of a siloxane copolymer additive, poly((2-phenylethyl) methylsiloxane)-co(1-phenylethyl) methylsiloxane)-co-dimethylsiloxane), which is fully soluble at room temperature, in a rapid-cure thermoset polyester coating formulation. The additive undergoes polymerization-induced phase segregation (PIPS) to self-assemble on the coating surface as discrete discoid nanofeatures during the resin cure process. Moreover, the copolymer facilitates surface co-segregation of titanium dioxide pigment microparticulate present in the coating. Depending on the composition, the coatings can display persistent superhydrophobicity and self-cleaning properties and, surprisingly, the titanium dioxide pigmented coatings that include the siloxane copolymer additive display high levels of antibacterial performance against Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria. This antibacterial performance is believed to be associated with the unique surface topology of these coatings, which comprise stimuli-responsive discoid nanofeatures. This paper provides details of the surface morphology of the coatings and how these relates to the antimicrobial properties of the coating.

Gelled Graphene Oxide-Ionic Liquid Composite Membranes with Enriched Ionic Liquid Surfaces for Improved CO2 Separation.

Blends containing ionic liquid (IL) 1-ethyl-3-methyimidazolium tetrafluoroborate [emim][BF4] gelled with Pebax 1657 block copolymers were modified by adding graphene oxide (GO) and fabricated in the form of thin film composite hollow fiber membranes. Their carbon dioxide (CO2) separation performance was evaluated using CO2 and N2 gas permeation and low-pressure adsorption measurements, and the morphology of films was characterized using scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. Upon small addition of GO into the IL-dominated environment, the interaction between IL and GO facilitated the migration of IL to the surface while suppressing the interaction between IL and Pebax, which was confirmed using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Amplified migration of IL to the surface and better dispersion of GO stacks were further achieved under alkaline conditions. With the enriched IL on the surface, the gas permeation through the films at 0.5 wt % GO and approximately 80 wt % IL loading reached 1000 GPU for CO2 with their CO2/N2 selectivity (up to 44) approaching that of pure IL.

A clinical practice guideline for the use of hyperbaric oxygen therapy in the treatment of diabetic foot ulcers.

BACKGROUND: The role of hyperbaric oxygen (HBO2) for the treatment of diabetic foot ulcers (DFUs) has been examined in the medical literature for decades. There are more systematic reviews of the HBO2/DFU literature than there have been randomized controlled trials (RCTs), but none of these reviews has resulted in a clinical practice guideline (CPG) that clinicians, patients and policy-makers can use to guide decision-making in everyday practice. METHODS: The Undersea and Hyperbaric Medical Society (UHMS), following the methodology of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group, undertook this systematic review of the HBO2 literature in order to rate the quality of evidence and generate practice recommendations for the treatment of DFUs. We selected four clinical questions for review regarding the role of HBO2 in the treatment of DFUs and analyzed the literature using patient populations based on Wagner wound classification and age of the wound (i.e., acute post-operative wound vs. non-healing wound of 30 or more days). Major amputation and incomplete healing were selected as critical outcomes of interest. RESULTS: This analysis showed that HBO2 is beneficial in preventing amputation and promoting complete healing in patients with Wagner Grade 3 or greater DFUs who have just undergone surgical debridement of the foot as well as in patients with Wagner Grade 3 or greater DFUs that have shown no significant improvement after 30 or more days of treatment. In patients with Wagner Grade 2 or lower DFUs, there was inadequate evidence to justify the use of HBO2 as an adjunctive treatment. CONCLUSIONS: Clinicians, patients, and policy-makers should engage in shared decision-making and consider HBO2 as an adjunctive treatment of DFUs that fit the criteria outlined in this guideline. The current body of evidence provides a moderate level of evidence supporting the use of HBO2 for DFUs. Future research should be directed at improving methods for patient selection, testing various treatment protocols and improving our confidence in the existing estimates.

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue with amyloid deposition: a clinicopathologic case series.

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) lymphoma is a mature B-cell neoplasm that typically follows an indolent clinical course. Amyloid deposition associated with MALT lymphoma is uncommon. We describe the clinical and pathologic features of 20 cases of MALT lymphoma and associated amyloid deposition across diverse primary sites. Frozen section immunofluorescence performed on 4 cases suggests that these deposits are a localized form of AL amyloid. Clinical follow-up was available for 15 patients. Amyloid deposits distant from the initial site occurred in 5 cases, always at sites also involved by the underlying lymphoma. No definitive evidence of systemic amyloidosis affecting the heart, kidneys, or liver was present in any patient. Given the generally indolent clinical behavior of MALT lymphomas with associated amyloid, we do not recommend extensive follow-up testing for systemic amyloidosis or more aggressive therapy than would be indicated for other MALT lymphomas of similar clinical stage.