Viral Filtration Using Carbon-Based Materials

Viral infections alone are a significant cause of morbidity and mortality worldwide and have a detrimental impact on global healthcare and socioeconomic development. The discovery of novel antiviral treatments has gained tremendous attention and support with the rising number of viral outbreaks. In this work, carbonaceous materials, including graphene nanoplatelets and graphene oxide nanosheets, were investigated for antiviral properties. The materials were characterised using scanning electron microscopy and transmission electron microscopy. Analysis showed the materials to be two-dimensional with lateral dimensions ranging between 1 - 4 µm for graphene oxide, 110 ± 0.11nm for graphene nanoplatelets. Antiviral properties were assessed against a DNA virus model microorganism at concentrations of 0.5, 1.0 and 2.0 wt/v%. Both carbonaceous nanomaterials exhibited potent antiviral properties and gave rise to a viral reduction of 100% across all concentrations tested. Graphene oxide nanosheets were then incorporated into polymeric fibres and their antiviral behaviour was examined after 3 and 24 hours. A viral reduction of ~39% was observed after 24 hours of exposure. The research presented here showcases, for the first time, the antiviral potential of several carbonaceous nanomaterials, also included in a carrier polymer. These outcomes can be translated and implemented in many fields and devices to prevent viral spread and infection

Does size matter? The impact of a small but targeted cleaning training intervention within a paediatric ward

Background: Cleaning is a critical tool for infection prevention and control, and is a key intervention for preventing healthcare associated infections (HCAIs) and controlling intermediate transmission routes between patient and environment. This study sought to identify potential areas of weakness in clinical surface cleaning, and assess the effectiveness of a staff group specific training intervention. Observations: One-hundred hours of audit observations in a paediatric cardiac intensive care unit (CICU) assessed surface cleaning technique of healthcare staff within bedspaces. Cleaning was assessed with a 5-component bundle, with each cleaning opportunity scored out of five. Training Intervention: Fifty hours of audit observations before and after a training intervention tested the efficacy of a staff group specific education intervention. The intervention was developed and implemented for 69% of nurses and 100% of cleaners. Results: One hundred and eighteen cleaning opportunities were observed before training, and scored an average of 2.4. One hundred and twenty-one cleaning opportunities were observed after training and scored an average 3.0. On average, before training, each cleaning opportunity by nurses and cleaners fulfilled 2.4 and 2.5, respectively, of the 5 bundle components. Following training, this improved to 3.3 and 2.9 respectively. There was a statistically significant improvement in bundle scores for nurses (P=.004) and cleaners (P=.0003). Conclusions: Surface wipe methods were inconsistent between all staff groups. The education based intervention resulted in a small improvement in most of the cleaning components. This study has identified how a small but targeted cleaning training intervention can have a significant (P= <.0001) impact on cleaning bundle compliance for both nurses and cleaners

Copper nanowire embedded hypromellose: An antibacterial nanocomposite film

The present work reports a novel antibacterial nanocomposite film comprising of copper nanowire impregnated biocompatible hypromellose using polyethylene glycol as a plasticiser. Detailed physico-chemical characterization using X-ray diffraction, Fourier transform infrared spectroscopy, UV–Visible spectroscopy and electron microscopy shows uniform dispersion of copper nanowire in the polymer matrix without any apparent oxidation. The film is flexible and shows excellent antibacterial activity against both Gram positive and negative bacteria at 4.8 wt% nanowire loading with MIC values of 400 µg/mL and 500 µg/mL for E. coli and S. aureus respectively. Investigation into the antibacterial mechanism of the nanocomposite indicates multiple pathways including cellular membrane damage caused by released copper ions and reactive oxygen species generation in the microbial cell. Interestingly, the film showed good biocompatibility towards normal human dermal fibroblast at minimum bactericidal concentration (MBC). Compared to the copper nanoparticles reported earlier in vitro studies, this low cytotoxicity of copper nanowires is due to the slow dissolution rate of the film and production of lower amount of ROS producing Cu2+ ions. Thus, the study indicates a strong potential for copper nanowire-based composites films in broader biomedical and clinical applications

Controlling Legionella pneumophila in water systems at reduced hot water temperatures with copper and silver ionization

Background: Hospital-acquired Legionnaires’ disease is associated with the presence of Legionella pneumophila in hospital water systems. In the United Kingdom, the Department of Health recommends maintaining hot water temperatures >55°C and cold water temperatures <20°C at the point of delivery to prevent proliferation of L pneumophila in water systems. In this study, we evaluated the efficacy of copper and silver ionization to control L pneumophila at deliberately reduced hot water temperatures (43°C) within a newly installed water system in a new building linked to a large health care facility in the United Kingdom. / Methods: One thousand, five hundred ninety-eight water samples were collected between September 2011 and June 2017. Samples were tested using accredited methods for L pneumophila, copper and silver ion levels, and total viable counts. Energy consumption and water usage data were also collected to permit carbon emission calculations. / Results: The results of 1,598 routine samples from September 2011 to June 2017, and the recordings of temperatures at outlets in this facility, demonstrated effective (100%) L pneumophila control throughout the study period with an average hot water temperature of 42°C. The energy savings and reduction of carbon emissions were calculated to amount to 33% and 24%, respectively, compared to an equivalent temperature-controlled system. Water system management interventions were required to achieve consistently adequate levels of copper and silver across outlets. / Conclusions: This study demonstrated that it is possible to control L pneumophila independent of temperature when copper and silver ionization is introduced into a new building in conjunction with an appropriately managed water system

The use of salicylaldehyde derivatives as a nitrogen source for antibiotic production by Streptomyces hygroscopicus CH-7

In the present work, four derivatives of salicylaldehyde (salicylaldehyde-hydrazone, phenylhydrazone, semicarbazone and thiosemicarbazone) were synthesized using both conventional (95% ethanol) and green (crude glycerol from biodiesel production) solvents. The obtained compounds were identified by elemental microanalysis, as well as FTIR, UV/Vis and H-1-NMR spectroscopic methods. Yields of 93-98% of the compounds in crude glycerol were achieved within 10-25 min. The derivatives of salicylaldehyde and crude glycerol were used as a nitrogen and carbon source, respectively, in the medium for antibiotic (hexaene H-85 and azalomycine B) production by Streptomyces hygroscopicus CH-7. The highest concentrations of hexaene H-85 and azalomycine B were achieved in the medium containing salicylaldehyde-thiosemicarbazone (198 and 69 mu g/cm(3), respectively). Derivatives of salicylaldehyde also impacted the strain morphology. In the media with salicylaldehyde- phenylhydrazone and salicylaldehyde-thiosemicarbazone, S. hygroscopicus CH-7 grew like large dispersive pellets with long twisted filaments that produced the highest yield of the antibiotics

In-situ fluorescence spectroscopy indicates total bacterial abundance and dissolved organic carbon

We explore in-situ fluorescence spectroscopy as an instantaneous indicator of total bacterial abundance and faecal contamination in drinking water. Eighty-four samples were collected outside of the recharge season from groundwater-derived water sources in Dakar, Senegal. Samples were analysed for tryptophan-like (TLF) and humic-like (HLF) fluorescence in-situ, total bacterial cells by flow cytometry, and potential indicators of faecal contamination such as thermotolerant coliforms (TTCs), nitrate, and in a subset of 22 samples, dissolved organic carbon (DOC). Significant single-predictor linear regression models demonstrated that total bacterial cells were the most effective predictor of TLF, followed by on-site sanitation density; TTCs were not a significant predictor. An optimum multiple-predictor model of TLF incorporated total bacterial cells, nitrate, nitrite, on-site sanitation density, and sulphate (r2 0.68). HLF was similarly related to the same parameters as TLF, with total bacterial cells being the best correlated (ρs 0.64). In the subset of 22 sources, DOC clustered with TLF, HLF, and total bacterial cells, and a linear regression model demonstrated HLF was the best predictor of DOC (r2 0.84). The intergranular nature of the aquifer, timing of the study, and/or non-uniqueness of the signal to TTCs can explain the significant associations between TLF/HLF and indicators of faecal contamination such as on-site sanitation density and nutrients but not TTCs. The bacterial population that relates to TLF/HLF is likely to be a subsurface community that develops in-situ based on the availability of organic matter originating from faecal sources. In-situ fluorescence spectroscopy instantly indicates a drinking water source is impacted by faecal contamination but it remains unclear how that relates specifically to microbial risk in this setting

Evaluation of Plant and Fungal Extracts for Their Potential Antigingivitis and Anticaries Activity

The link between diet and health has lead to the promotion of functional foods which can enhance health. In this study, the oral health benefits of a number of food homogenates and high molecular mass and low molecular mass fractions were investigated. A comprehensive range of assays were performed to assess the action of these foods on the development of gingivitis and caries using bacterial species associated with these diseases. Both antigingivitis and anticaries effects were investigated by assays examining the prevention of biofilm formation and coaggregation, disruption of preexisting biofilms, and the foods' antibacterial effects. Assays investigating interactions with gingival epithelial cells and cytokine production were carried out to assess the foods' anti- gingivitis properties. Anti-caries properties such as interactions with hydroxyapatite, disruption of signal transduction, and the inhibition of acid production were investigated. The mushroom and chicory homogenates and low molecular mass fractions show promise as anti-caries and anti-gingivitis agents, and further testing and clinical trials will need to be performed to evaluate their true effectiveness in humans

Aerodynamic investigations of ventilated brake discs.

The heat dissipation and performance of a ventilated brake disc strongly depends on the aerodynamic characteristics of the flow through the rotor passages. The aim of this investigation was to provide an improved understanding of ventilated brake rotor flow phenomena, with a view to improving heat dissipation, as well as providing a measurement data set for validation of computational fluid dynamics methods. The flow fields at the exit of four different brake rotor geometries, rotated in free air, were measured using a five-hole pressure probe and a hot-wire anemometry system. The principal measurements were taken using two-component hot-wire techniques and were used to determine mean and unsteady flow characteristics at the exit of the brake rotors. Using phase-locked data processing, it was possible to reveal the spatial and temporal flow variation within individual rotor passages. The effects of disc geometry and rotational speed on the mean flow, passage turbulence intensity, and mass flow were determined. The rotor exit jet and wake flow were clearly observed as characterized by the passage geometry as well as definite regions of high and low turbulence. The aerodynamic flow characteristics were found to be reasonably independent of rotational speed but highly dependent upon rotor geometry

Tryptophan-like and humic-like fluorophores are extracellular in groundwater: implications as real-time faecal indicators

Fluorescent natural organic matter at tryptophan-like (TLF) and humic-like fluorescence (HLF) peaks is associated with the presence and enumeration of faecal indicator bacteria in groundwater. We hypothesise, however, that it is predominantly extracellular material that fluoresces at these wavelengths, not bacterial cells. We quantified total (unfiltered) and extracellular (filtered at < 0.22 µm) TLF and HLF in 140 groundwater sources across a range of urban population densities in Kenya, Malawi, Senegal, and Uganda. Where changes in fluorescence occurred following filtration they were correlated with potential controlling variables. A significant reduction in TLF following filtration (ΔTLF) was observed across the entire dataset, although the majority of the signal remained and thus considered extracellular (median 96.9%). ΔTLF was only significant in more urbanised study areas where TLF was greatest. Beneath Dakar, Senegal, ΔTLF was significantly correlated to total bacterial cells (ρs 0.51). No significant change in HLF following filtration across all data indicates these fluorophores are extracellular. Our results suggest that TLF and HLF are more mobile than faecal indicator bacteria and larger pathogens in groundwater, as the predominantly extracellular fluorophores are less prone to straining. Consequently, TLF/HLF are more precautionary indicators of microbial risks than faecal indicator bacteria in groundwater-derived drinking water