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Biofilm formation is a dynamic process that leads to mature communities over time. Despite a general knowledge of biofilm community formation and the resultant limitations of antibiotic therapy, there is a paucity of data describing specific plume heights, surface coverage and rates of maturation. Furthermore, little is published on the effect that the broth medium might have on the degree of biofilm maturation. In this study, three strains of methicillin-resistant Staphylococcus aureus (MRSA) (USA300, USA400 and a clinical isolate) were grown in brain heart infusion broth (BHI) or tryptic soy broth (TSB). Following growth, SEM images were captured for 3-D analysis to assess plume height. TSB produced significantly higher plume heights of USA300 and USA400 compared to BHI. Broth type was less influential on the clinical isolate. The data indicate that broth type and time may be important factors to consider when assessing maturation and plume height formation of MRSA biofilms. [ABSTRACT FROM AUTHOR]

ABSTRACT: Flash autoclaving is one of the most frequently utilized methods of sterilizing devices, implants or other materials. For a number of decades, it has been common practice for surgeons to remove implantable devices, flash autoclave and then reimplant them in a patient. Data have not yet indicated the potential for biofilms to survive or remain on the surface of orthopaedic‐relevant materials following flash autoclave. In this study, monomicrobial and polymicrobial biofilms were grown on the surface of clinically relevant titanium materials and exposed to flash autoclave settings that included varying times and temperatures. Data indicated that when the sterilization and control temperatures of an autoclave were the same, biofilms were able to survive flash autoclaving that was performed for a short duration. Higher temperature and increased duration rendered biofilms non‐viable, but none of the autoclave settings had the ability to remove or disperse the presence of biofilms from the titanium surfaces. These findings may be beneficial for facilities, clinics, or hospitals to consider if biofilms are suspected to be present on materials or devices, in particular implants that have had associated infection and are considered for re‐implantation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1543–1550, 2018. [ABSTRACT FROM AUTHOR]

Predicting the risk of traffic demands and delays exceeding critical limits at road junctions, airports, hospitals, etc., requires knowing how both mean and variance of queue size vary over time. Microscopic simulation can explore variability but is computationally demanding and gives only sample results. A computationally efficient approximation to the mean is used in many modelling tools, but only empirical extensions for variance in particular situations have been available. The paper derives theoretical formulae for time-dependent and equilibrium variance, believed to be novel and to apply generally to queues covered by the Pollaczek–Khinchin mean formula, and offering possible structural insights. These are applied in an extended approximation giving mutually consistent mean and variance estimates with improved accuracy. Tests on oversaturated peak demand cases are compared with Markov probabilistic simulation, demonstrating accuracy (R2 > 0.99) for typical random, priority-like (M/M/1) and traffic-signal-like (M/D/1) queues. Implications for risk analysis, planning and policy are considered. [ABSTRACT FROM AUTHOR]

Queues are often associated with uncertainty or unreliability, which can arise from chance or climatic events, phase changes in system behaviour, or inherent randomness. Knowing the probability distribution of the number of customers in a queue is important for estimating the risk of stress or disruption to routine services and upstream blocking, potentially leading to exceeding critical limits, gridlock or incidents. The present paper focuses on time-varying queues produced by transient oversaturation during demand peaks where there is randomness in arrivals and service. The objective is to present practical methods for estimating a probability distribution from knowledge of the mean, variance and utilisation (degree of saturation) of a queue available from computationally efficient, if approximate, time-dependent calculation. This is made possible by a novel expression for time-dependent queue variance. The queue processes considered are those commonly used to represent isolated priority (M/M/1) and signal-like (M/D/1) systems, plus some statistical variations within the common Pollaczek-Khinchin framework. Results are verified by comparison with Markov simulation based on recurrence relations. [ABSTRACT FROM AUTHOR]

Many analyses of traffic signal queues use Webster and Cobbe's formula, which combines the net effect of the red/green cycle with a term representing stochastic effects, idealised as an M/D/1 queue process having random arrivals and uniform service. Several authors have noted that this component should depend not only on demand intensity but also on throughput capacity in each green period, although an extra empirical term may partially allow for this. Extending the service interval in M/D/1 (M = Markovian, i.e. random, D = deterministic, i.e. uniform, 1 = one server) enables the effect to be reproduced, but no exact expressions for its moments are found. Approximate formulae for the extended mean exist but are accurate only near saturation. The paper derives novel approximations for the equilibrium mean and also variance and utilisation, using functions linking traffic intensity with green period capacity. With three moments, equilibrium probability distributions can be estimated for which a method based on a doubly nested geometric distribution is described. [ABSTRACT FROM PUBLISHER]

Pressure on transport networks from increased demand to travel combined with reducing investment in highway infrastructure is leading to significant interest in the use of transport telematics. Telematics systems are aimed at making the most of existing infrastructure through, for example, area traffic control, electronic tolling and traveller information. Although there are quite high levels of activity in the application and implementation of some systems, there remains a significant dearth of evidence of the impact these systems will have on behaviour and travel patterns. It is important that appropriate appraisal methodologies are available to assess the impact of new systems. Modelling is an appropriate method of appraisal as it enables system-wide impacts of individual responses to be predicted. This paper is concerned with the advances required in order that modelling techniques are available for this purpose. Modelling requirements are identified from reviews of technologies, behavioural responses and modelling procedures. Advice is given on both enhancements to existing modelling procedures and the structure of a modelling system that fully meets assessment needs. Recommendations are made on steps to be taken towards this. [ABSTRACT FROM AUTHOR]

The article discusses public transport has improved has held as offering sustainable mobility in n increasingly urbanised and environment-sensitive world, has still felt like pushing water, or a river of petroleum, uphill.

A letter to the editor is presented in response to the article in the January 2017 issue regarding food obtained from plants in Christmas 2050.

Obtaining a biopsy of the physis in a pediatric/juvenile could provide the ability to diagnose and manage children with physeal abnormalities. However, it has not yet been determined whether a physeal biopsy procedure affects angular deformity. We employed a rabbit model to collect biopsies of the distal femoral and proximal tibial physes on anesthetized, 8-week old New Zealand rabbits. The contralateral limb served as a control. At 8 (n = 5) and 16 (n = 5) weeks postbiopsy, animals were euthanized. Micro-computed tomography (CT) was employed to estimate percentage of the physis biopsied and assess structural abnormalities resulting from biopsy. Bone samples were embedded in polymethylmethacrylate and analyzed. The percentage of physis sampled was ≤1.5% of the total femoral physis while all but one of the tibiae had ≤2.3% removed. There were no iatrogenic clinical or radiographic deformities (frontal or sagittal). Micro-CT and histological analysis suggested that physeal defects had signs of healing that did not lead to subsequent angular deviation. A defect caused by physeal biopsy may not lead to angular deformity. Long-term data could help determine the safety and efficacy of collecting biopsies for histological analyses. Advanced imaging may demonstrate a detailed picture of anatomic or structural alteration of a given physis, but provides no functional information. The diagnostic and therapeutic information that could be gleaned from one or more serial biopsy samples could be invaluable in decision making and clinical management (e.g. skeletal dysplasias and metabolic conditions), so long as subsequent deformity is not a future possibility.

Flash autoclaving is one of the most frequently utilized methods of sterilizing devices, implants or other materials. For a number of decades, it has been common practice for surgeons to remove implantable devices, flash autoclave and then reimplant them in a patient. Data have not yet indicated the potential for biofilms to survive or remain on the surface of orthopaedic-relevant materials following flash autoclave. In this study, monomicrobial and polymicrobial biofilms were grown on the surface of clinically relevant titanium materials and exposed to flash autoclave settings that included varying times and temperatures. Data indicated that when the sterilization and control temperatures of an autoclave were the same, biofilms were able to survive flash autoclaving that was performed for a short duration. Higher temperature and increased duration rendered biofilms non-viable, but none of the autoclave settings had the ability to remove or disperse the presence of biofilms from the titanium surfaces. These findings may be beneficial for facilities, clinics, or hospitals to consider if biofilms are suspected to be present on materials or devices, in particular implants that have had associated infection and are considered for re-implantation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1543-1550, 2018., (© 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)