Validation of the Decontamination of a Specialist Transport System for Patients with High Consequence Infectious Diseases

When transferring highly infective patients to specialist hospitals, safe systems of work minimise the risk to healthcare staff. The EpiShuttle is a patient transport system that was developed to fit into an air ambulance. A validated decontamination procedure is required before the system can be adopted in the UK. Hydrogen peroxide (H2O2) vapour fumigation may offer better penetration of the inaccessible parts than the liquid disinfectant wiping that is currently suggested. To validate this, an EpiShuttle was fumigated in a sealed test chamber. Commercial bacterial spore indicators (BIs), alongside organic liquid suspensions and dried surface samples of MS2 bacteriophage (a safe virus surrogate), were placed in and around the EpiShuttle, for the purpose of evaluation. The complete kill of all of the BIs in the five test runs demonstrated the efficacy of the fumigation cycle. The log reduction of the MS2 that was dried on the coupons ranged from 2.66 to 4.50, but the log reduction of the MS2 that was in the organic liquids only ranged from 0.07 to 1.90, confirming the results of previous work. Fumigation with H2O2 alone may offer insufficient inactivation of viruses in liquid droplets, therefore a combination of fumigation and disinfectant surface wiping was proposed. Initial fumigation reducing contamination with minimal intervention allows disinfectant wipe cleaning to be completed more safely, with a second fumigation step inactivating the residual pathogens.

In Vitro Toxicity of Industrially Relevant Engineered Nanoparticles in Human Alveolar Epithelial Cells: Air–Liquid Interface versus Submerged Cultures

Diverse industries have already incorporated within their production processes engineered nanoparticles (ENP), increasing the potential risk of worker inhalation exposure. In vitro models have been widely used to investigate ENP toxicity. Air–liquid interface (ALI) cell cultures have been emerging as a valuable alternative to submerged cultures as they are more representative of the inhalation exposure to airborne nano-sized particles. We compared the in vitro toxicity of four ENP used as raw materials in the advanced ceramics sector in human alveolar epithelial-like cells cultured under submerged or ALI conditions. Submerged cultures were exposed to ENP liquid suspensions or to aerosolised ENP at ALI. Toxicity was assessed by determining LDH release, WST-1 metabolisation and DNA damage. Overall, cells were more sensitive to ENP cytotoxic effects when cultured and exposed under ALI. No significant cytotoxicity was observed after 24 h exposure to ENP liquid suspensions, although aerosolised ENP clearly affected cell viability and LDH release. In general, all ENP increased primary DNA damage regardless of the exposure mode, where an increase in DNA strand-breaks was only detected under submerged conditions. Our data show that at relevant occupational concentrations, the selected ENP exert mild toxicity to alveolar epithelial cells and exposure at ALI might be the most suitable choice when assessing ENP toxicity in respiratory models under realistic exposure conditions.

Precision size and refractive index analysis of weakly scattering nanoparticles in polydispersions.

Characterization of the size and material properties of particles in liquid suspensions is in very high demand, e.g., for the analysis of colloidal samples or of bodily fluids such as urine or blood plasma. However, the existing methods are limited in deciphering the constituents of realistic samples. Here, we introduce iNTA as a new method, which combines interferometric detection of scattering with nanoparticle tracking analysis, to reach an unprecedented sensitivity and precision in determining the size and refractive index distributions of nanoparticles in suspensions. After benchmarking iNTA with samples of colloidal gold, we present its remarkable ability to resolve the constituents of various multi-component and polydisperse samples of known origin. Furthermore, we showcase the method by elucidating the refractive index and size distributions of extracellular vesicles from Leishmania parasites and nanoparticles in human urine. The current performance of iNTA already enables advances in several important applications, but we also discuss possible improvements.

Encapsulation of Cochleates Derived from Salmonella Infantis with Biopolymers to Develop a Potential Oral Poultry Vaccine

The aim of this study was to develop and characterize Salmonellaenterica serovar Infantis (S. Infantis) cochleates protected by encapsulation technology as a potential vaccine and to determine its safety in pullets. Cochleates were encapsulated by two technologies, spray drying and ionotropic gelation at different concentrations (0–15% v/v), and were characterized by physicochemical properties, protein content and Fourier Transform Infrared Spectroscopy (FTIR). The cochleates were white liquid suspensions with tubular shapes and a protein content of 1.0–2.1 mg/mL. After encapsulation by spray drying, microparticles ranged in size from 10.4–16.9 µm, were spherical in shape, and the protein content was 0.7–1.8 mg/g. After encapsulation by ionotropic gelation, beads ranged in size from 1620–1950 µm and were spherical in shape with a protein content of 1.0–2.5 mg/g. FTIR analysis indicated that both encapsulation processes were efficient. The cochleates encapsulated by ionotropic gelation were then tested for safety in pullets. No ill effect on the health of animals was observed upon physical or postmortem examination. In conclusion, this study was the first step in developing a potential oral S. Infantis vaccine safe for poultry using a novel cochleate encapsulation technology. Future studies are needed to determine the effectiveness of the vaccine.

A Finite Element/Neural Network Framework for Modeling Suspensions of Non-spherical Particles

An accurate prediction of the translational and rotational motion of particles suspended in a fluid is only possible if a complete set of correlations for the force coefficients of fluid-particle interaction is known. The present study is thus devoted to the derivation and validation of a new framework to determine the drag, lift, rotational and pitching torque coefficients for different non-spherical particles in a fluid flow. The motivation for the study arises from medical applications, where particles may have an arbitrary and complex shape. Here, it is usually not possible to derive accurate analytical models for predicting the different hydrodynamic forces. The presented model is designed to be applicable to a broad range of shapes. Another important feature of the suspensions occurring in medical and biological applications is the high number of particles. The modelling approach we propose can be efficiently used for simulations of solid-liquid suspensions with numerous particles. Based on resolved numerical simulations of prototypical particles we generate data to train a neural network which allows us to quickly estimate the hydrodynamic forces experienced by a specific particle immersed in a fluid.

Ultrasonic Time-of-Flight Computed Tomography for Investigation of Batch Crystallisation Processes

Crystallisation is a crucial step in many industrial processes. Many sensors are being investigated for monitoring such processes to enhance the efficiency of them. Ultrasound techniques have been used for particle sizing characterization of liquid suspensions, in crystallisation process. An ultrasound tomography system with an array of ultrasound sensors can provide spatial information inside the process when compared to single-measurement systems. In this study, the batch crystallisation experiments have been conducted in a lab-scale reactor in calcium carbonate crystallisation. Real-time ultrasound tomographic imaging is done via a contactless ultrasound tomography sensor array. The effect of the injection rate and the stirring speed was considered as two control parameters in these crystallisation functions. Transmission mode ultrasound tomography comprises 32 piezoelectric transducers with central frequency of 40 kHz has been used. The process-based experimental investigation shows the capability of the proposed ultrasound tomography system for crystallisation process monitoring. Information on process dynamics, as well as process malfunction, can be obtained via the ultrasound tomography system.

EFFECT OF HYDROSTATIC PRESSURE ON THE VIABILITY OF EPN NATIVE ITALIAN STRAINS STEINERNEMA FELTIAEAND HETERORHABDITIS BACTERIOPHORA

The use of entomopathogenic nematodes (EPNs)as a non-chemical treatment system is one of the most mo-dern techniques promoted by the 2008/128/EC standards for the biological control of plant pathogens. The distri-bution ofEPNscould be carried out with the same sprayers used for the distribution of pesticides. This research is focusedon the effects of the mechanical stress due to hydraulic compression on EPNsItalianstrains,Stei-nernemafeltiaeand Heterorhabditisbacteriophora, to assess their residual strength and vitality under laboratory tests. Liquid suspensions of nematodes were subjected to 8 different levels of hydrostatic pressure from 5 to 40 bar. The hydraulic compression test was conducted through a hydrostatic compression system specifically de-signed for the experimental test. Although correlation curves show an increment of14%in nematode mortality, the statistical analysisdid not show any significant effect of static pressure on the vitality and infectivity of EPNs, that makes them suitable for field application with sprayers. These preliminary positive results on the effects of compression on the viability of EPNsare preparatory to subsequent field tests under high pressure