Functional Nanogels as Platforms for Imparting Antibacterial,Antibiofilm, and Antiadhesion Activities to Stainless Steel

In this work, long‐term antibacterial, antiadhesion, and antibiofilm activities are afforded to industrial stainless steel surfaces following a green and bio‐inspired strategy. Starting from catechol bearing synthetic polymers, the film cross‐linking and the grafting of active (bio)molecules are possible under environmentally friendly conditions (in aqueous media and at room temperature). A bio‐inspired polyelectrolyte, a polycation‐bearing catechol, is used as the film‐anchoring polymer while a poly(methacrylamide)‐bearing quinone groups serves as the cross‐linking agent in combination with a polymer bearing primary amine groups. The amine/quinone reaction is exploited to prepare stable solutions of nanogels in water at room temperature that can be easily deposited to stainless steel. This coating provides quinone‐functionalized surfaces that are then used to covalently anchor active (bio)molecules (antibiofilm enzyme and antiadhesion polymer) through thiol/quinone reactions.     

Small RNAs beyond Model Organisms: Have We Only Scratched the Surface?

Small RNAs (sRNAs) are essential regulators in the adaptation of bacteria to environmental changes and act by binding targeted mRNAs through base complementarity. Approximately 550 distinct families of sRNAs have been identified since their initial characterization in the 1980s, accelerated by the emergence of RNA-sequencing. Small RNAs are found in a wide range of bacterial phyla, but they are more prominent in highly researched model organisms compared to the rest of the sequenced bacteria. Indeed, Escherichia coli and Salmonella enterica contain the highest number of sRNAs, with 98 and 118, respectively, with Enterobacteriaceae encoding 145 distinct sRNAs, while other bacteria families have only seven sRNAs on average. Although the past years brought major advances in research on sRNAs, we have perhaps only scratched the surface, even more so considering RNA annotations trail behind gene annotations. A distinctive trend can be observed for genes, whereby their number increases with genome size, but this is not observable for RNAs, although they would be expected to follow the same trend. In this perspective, we aimed at establishing a more accurate representation of the occurrence of sRNAs in bacteria, emphasizing the potential for novel sRNA discoveries.     

Genotoxic effects of food contact recycled paperboard extracts on two human hepatic cell lines

Food contact paperboards may be a potential source of food contamination as they can release chemicals (intentionally added or not), especially recycled paperboards. This study assessed the in vitro genotoxicity of food contact paperboard samples from a manufacturer, collected at the beginning and at the end of a recycling production chain. Samples were extracted in water to mimic a wet food contact. Different genotoxic endpoints were evaluated in two human hepatic cell lines (HepG2 and HepaRG) using bioassays: γH2AX and p53 activation, primary DNA damage with the comet assay and micronucleus formation. It was found that the samples from the beginning and the end of the production chain induced, with the same potency, γH2AX and p53-ser15 activation and DNA damage with the comet assay. The micronucleus assay was negative with the paperboard extract from the beginning of the chain, whereas positive data were observed for the end paperboard extract. These results indicate that samples from recycled food contact paperboard can induce in vitro genotoxic effects in this study’s experimental conditions.     

Efficient Total Nitrogen Removal in an Ammonia Gas Biofilter through High-Rate OLAND

Ammonia gas is conventionally treated in nitrifying biofilters; however, addition of organic carbon to perform post-denitrification is required to obtain total nitrogen removal. Oxygen-limited autotrophic nitrification/denitrification (OLAND), applied in full-scale for wastewater treatment, can offer a cost-effective alternative for gas treatment. In this study, the OLAND application thus was broadened toward ammonia loaded gaseous streams. A down flow, oxygen-saturated biofilter (height of 1.5 m; diameter of 0.11 m) was fed with an ammonia gas stream (248 ± 10 ppmv) at a loading rate of 0.86 ± 0.04 kg N m(-3) biofilter d(-1) and an empty bed residence time of 14 s. After 45 days of operation a stable nitrogen removal rate of 0.67 ± 0.06 kg N m(-3) biofilter d(-1), an ammonia removal efficiency of 99%, a removal of 75-80% of the total nitrogen, and negligible NO/N(2)O productions were obtained at water flow rates of 1.3 ± 0.4 m(3) m(-2) biofilter section d(-1). Profile measurements revealed that 91% of the total nitrogen activity was taking place in the top 36% of the filter. This study demonstrated for the first time highly effective and sustainable autotrophic ammonia removal in a gas biofilter and therefore shows the appealing potential of the OLAND process to treat ammonia containing gaseous streams.     

Mechanical Properties of Highly Deformable Elastomeric Gyroids for Multifunctional Capacitors

Triply periodic minimal surface lattices have mechanical properties that derive from the unit cell geometry and the base material. Through computation software like nTopology and Abaqus, these geometries are used to tune nonlinear stress–strain curves not readily achievable with solid materials alone and to change the compliance by two orders of magnitude compared to the constituent material. In this study, four elastomeric TPMS gyroids undergo large deformation compression and tension testing to investigate the impact of the structure's geometry on the mechanical properties. Among all the samples, the modulus at strain ε$=0.05$ varies by over one order of magnitude (7.7–293.4 kPa from FEA under compression). These lattices are promising candidates for designing multifunctional systems that can perform multiple tasks simultaneously by leveraging the geometry's large surface area to volume ratio. For example, the architectural functionality of the lattice to bear loads and store mechanical energy along with the larger surface area for energy storage is combined. A compliant double-gyroid capacitor that can simultaneously achieve three functions is demonstrated: load bearing, energy storage, and sensing.     

CO2 utilization in Eastern Canada: Sources,sites, and grid effects

Achieving net zero carbon dioxide (CO₂) emissions will require the cessation of fossil fuel emissions into the atmosphere, yet the need for ‘fuel’ and energy storage will remain. One solution could be a carbon-based fuel system where CO₂ of biogenic origin is converted to fuels using hydrogen generated by electrolysis powered by renewable energy sources. Methane has value as an initial target given its prevalence in biogas, use in home heating and in electricity generation. Sources of CO₂ in Eastern Canada are dominated by the iron and steel, cement, and aluminium industries, all of which have biogenic fuel options. Collecting all of the potentially biogenic CO₂ would displace 75% of current natural gas use and require a 50% increase in generating capacity. Initial efforts could site a carbon capture, utilization, and storage facility near Montreal, QC, with other large-scale facilities near Hamilton, ON, and Lac St-Jean, QC. These facilities would be grid connected and expected to operate ~6200 h annually. The most high-frequency electrolysis events would be 10 h of run time and 2 h of idle time. These periods would peak during the equinox months and be at a minimum during the winter solstice. These operational assumptions will all be subject to the increased variability caused by anthropogenic climate change and increased renewable generation on the grid. A closed-loop carbon-based fuel system would require an equivalent price of $250 per tonne CO₂.