Microbiota of cocoa powder with particular reference to aerobic thermoresistant spore-formers

The microbiological criteria of commercial cocoa powder are defined in guidelines instituted by the cocoa industry. Twenty-five commercial samples were collected with the aim of assessing the compliance with the microbiological quality guidelines and investigating the occurrence and properties of aerobic Thermoresistant Spores (ThrS). Seventeen samples complied with the guidelines, but one was positive for Salmonella, five for Enterobacteriaceae and two had mould levels just exceeding the maximum admissible level. The treatment of the cocoa powder suspensions from 100 °C to 170 °C for 10 min, revealed the presence of ThrS in 36% of the samples. In total 61 ThrS strains were isolated, of which the majority belonged to the Bacillus subtilis complex (65.6%).Strains resporulation and spore crops inactivation at 110 °C for 5 min showed a wide diversity of heat-resistance capacities. Amplified fragment length polymorphism analysis revealed not only a large intraspecies diversity, but also different clusters of heat-resistant spore-forming strains. The heat-resistance of spores of six B. subtilis complex strains was further examined by determination of their D and z-values.We concluded that B. subtilis complex spores, in particular those from strain M112, were the most heat-resistant and these may survive subsequent preservation treatments, being potentially problematic in food products, such as chocolate milk.     

An ordered Si nanowire with NiSi2 tip arrays as excellent field emitters

A method was developed to grow ordered silicon nanowire with NiSi(2) tip arrays by reacting nickel thin films on silica-coated ordered Si nanowire (NW) arrays. The coating of thin silica shell on Si NW arrays has the effect of limiting the diffusion of nickel during the silicidation process to achieve the single crystalline NiSi(2) NWs. In the meantime, it relieves the distortion of the NWs caused by the strain associated with formation of NiSi(2) to maintain the straightness of the nanowire and the ordering of the arrays. Other nickel silicide phases such as Ni(2)Si and NiSi were obtained if the silicidation processes were conducted on the ordered Si NWs without a thin silica shell. Excellent field emission properties were found for NiSi(2)/Si NW arrays with a turn on field of 0.82 V μm(-1) and a threshold field of 1.39 V μm(-1). The field enhancement factor was calculated to be about 2440. The stability test showed a fluctuation of about 7% with an applied field of 2.6 V μm(-1) for a period of 24 h. The excellent field emission characteristics are attributed to the well-aligned and highly ordered arrangement of the single crystalline NiSi(2)/Si heterostructure field emitters. In contrast to other growth methods, the present growth of ordered nickel silicide/Si NWs on silicon is compatible with silicon nanoelectronics device processes, and also provides a facile route to grow other well-aligned metal silicide NW arrays. The advantages will facilitate its applications as field emission devices.     

Fabrication of sticky and slippery superhydrophobic surfaces via spin-coating silica nanoparticles onto flat/patterned substrates

Silica nanoparticles were spin-coated onto a flat/patterned (regular pillar-like) substrate to enhance the surface roughness. The surface was further modified by a self-assembled fluorosilanated monolayer. The advancing/receding contact angle and sliding angle measurements were performed to determine the wetting behavior of a water droplet on the surface. It is interesting to find that a transition from a Wenzel surface to a sticky superhydrophobic surface is observed due to the spin-coating silica nanoparticles. A slippery superhydrophobic surface can be further obtained after secondary spin-coating with silica nanoparticles to generate a multi-scale roughness structure. The prepared superhydrophobic substrates should be robust for practical applications. The adhesion between the substrate and nanoparticles is also examined and discussed.     

Assessing cellular toxicities in fibroblasts upon exposure to lipid-based nanoparticles: a high content analysis approach

Lipid-based nanoparticles (LNPs) are widely used for the delivery of drugs and nucleic acids. Although most of them are considered safe, there is confusing evidence in the literature regarding their potential cellular toxicities. Moreover, little is known about the recovery process cells undergo after a cytotoxic insult. We have previously studied the systemic effects of common LNPs with different surface charge (cationic, anionic, neutral) and revealed that positively charged LNPs ((+)LNPs) activate pro-inflammatory cytokines and induce interferon response by acting as an agonist of Toll-like receptor 4 on immune cells. In this study, we focused on the response of human fibroblasts exposed to LNPs and their cellular recovery process. To this end, we used image-based high content analysis (HCA). Using this strategy, we were able to show simultaneously, in several intracellular parameters, that fibroblasts can recover from the cytotoxic effects of (+)LNPs. The use of HCA opens new avenues in understanding cellular response and nanotoxicity and may become a valuable tool for screening safe materials for drug delivery and tissue engineering.     

Self-regulation of motor vehicle advertising: is it working in Australia?

There is growing concern that certain content within motor vehicle advertising may have a negative influence on driving attitudes and behaviours of viewers, particularly young people, and hence a negative impact on road safety. In response, many developed countries have adopted a self-regulatory approach to motor vehicle advertising. However, it appears that many motor vehicle advertisements in Australia and elsewhere are not compliant with self-regulatory codes. Using standard commercial advertising methods, we exposed three motor vehicle ads that had been the subject of complaints to the Australian Advertising Standards Board (ASB) to, N = 463, 14–55 year olds to assess the extent to which their perceptions of the content of the ads communicated themes that were contrary to the Australian self-regulatory code. All three ads were found to communicate messages contrary to the code (such as the vehicle's speed and acceleration capabilities). However, the ASB had upheld complaints about only one of the ads. Where motor vehicle advertising regulatory frameworks exist to guide motor vehicle advertisers as to what is and what is not acceptable in their advertising, greater efforts are needed to ensure compliance with these codes. One way may be to make it mandatory for advertisers to report consumer pre-testing of their advertising to ensure that undesirable messages are not being communicated to viewers.     

Evaluation of the Click It or Ticket intervention in Utah

Objective

To evaluate the Click It or Ticket (CIOT) intervention conducted in Utah by comparing changes in safety belt use using observational safety belt surveys pre- and post-intervention.

Methods

Observational surveys of safety belt use for drivers and front seat passengers (collectively referred to as front seat occupants) were conducted before and after the media and enforcement blitz of the CIOT intervention. Data were collected from 16 urban sites during the daytime and nighttime. Logistic regression and generalized estimating equations were used to compute odds ratios for safety belt use adjusted for front seat occupant characteristics.

Results

Overall safety belt use was observed at 76.5% pre-intervention and 84.8% post-intervention, an improvement of 8.3% (95% confidence interval [CI]: 5.2%, 11.3%). Daytime and nighttime safety belt use improved by 7.8% (95% CI: 3.5%, 12.1%) and 9.7% (95% CI: 6.4%, 13.0%), respectively. While males showed a greater improvement (9.9%) in safety belt use when compared to females (5.7%); males were still less likely to use safety belts than females.

Conclusions

The CIOT intervention is associated with increased safety belt use at the sites observed in Utah, including among the two high risk groups targeted by the intervention: nighttime occupants and males.     

Calibration of multiplexed fiber-optic spectroscopy

Large-scale commercial bioprocesses that manufacture biopharmaceutical products such as monoclonal antibodies generally involve multiple bioreactors operated in parallel. Spectra recorded during in situ monitoring of multiple bioreactors by multiplexed fiber-optic spectroscopies contain not only spectral information of the chemical constituents but also contributions resulting from differences in the optical properties of the probes. Spectra with variations induced by probe differences cannot be efficiently modeled by the commonly used multivariate linear calibration models or effectively removed by popular empirical preprocessing methods. In this study, for the first time, a calibration model is proposed for the analysis of complex spectral data sets arising from multiplexed probes. In the proposed calibration model, the spectral variations introduced by probe differences are explicitly modeled by introducing a multiplicative parameter for each optical probe, and then their detrimental effects are effectively mitigated through a "dual calibration" strategy. The performance of the proposed multiplex calibration model has been tested on two multiplexed spectral data sets (i.e., MIR data of ternary mixtures and NIR data of bioprocesses). Experimental results suggest that the proposed calibration model can effectively mitigate the detrimental effects of probe differences and hence provide much more accurate predictions than commonly used multivariate linear calibration models (such as PLS) with and without empirical data preprocessing methods such as orthogonal signal correction, standard normal variate, or multiplicative signal correction.     

Analytical and sampling constraints in ²¹⁰Pb dating

²¹⁰Pb dating provides a valuable, widely used means of establishing recent chronologies for sediments and other accumulating natural deposits. The Constant Rate of Supply (CRS) model is the most versatile and widely used method for establishing ²¹⁰Pb chronologies but, when using this model, care must be taken to account for limitations imposed by sampling and analytical factors. In particular, incompatibility of finite values for empirical data, which are constrained by detection limit and core length, with terms in the age calculation, which represent integrations to infinity, can generate erroneously old ages for deeper sections of cores. The bias in calculated ages increases with poorer limit of detection and the magnitude of the disparity increases with age. The origin and magnitude of this effect are considered below, firstly for an idealised, theoretical ²¹⁰Pb profile and secondly for a freshwater lake sediment core. A brief consideration is presented of the implications of this potential artefact for sampling and analysis.