Smoking patterns in Great Britain: the rise of cheap cigarette brands and roll your own (RYO) tobacco

This is the final version. Available from Oxford University Press via the DOI in this record.Background In Britain, the tobacco industry segments cigarettes into four price categories—premium, mid-price, economy and ultra-low-price (ULP). Our previous work shows that tobacco companies have kept ULP prices stable in real terms. Roll your own (RYO) tobacco remains cheaper still. Methods Analysis of 2001–08 General Household Survey data to examine trends in use of these cheap products and, using logistic regression, the profile of users of these products. Results Among smokers, the proportion using cheap products (economy, ULP and RYO combined) increased significantly in almost all age groups and geographic areas. Increases were most marked in under 24 year olds, 76% of whom smoked cheap cigarettes by 2008. All cheap products were more commonly used in lower socio-economic groups. Men and younger smokers were more likely to smoke RYO while women smoked economy brands. Smokers outside London and the South East of England were more likely to smoke some form of cheap tobacco even once socio-economic differences were accounted for. Conclusions This paper demonstrates that cheap tobacco use is increasing among young and disadvantaged smokers compromising declines in population smoking prevalence. Thus, tobacco industry pricing appears to play a key role in explaining smoking patterns and inequalities in smoking

No effect of arm exercise on diaphragmatic fatigue or ventilatory constraint in Paralympic athletes with cervical spinal cord injury

Cervical spinal cord injury (CSCI) results in a decrease in the capacity of the lungs and chest wall for pressure, volume, and airflow generation. We asked whether such impairments might increase the potential for exercise-induced diaphragmatic fatigue and mechanical ventilatory constraint in this population. Seven Paralympic wheelchair rugby players (mean ± SD peak oxygen uptake = 16.9 ± 4.9 ml·kg–1·min–1) with traumatic CSCI (C5–C7) performed arm-crank exercise to the limit of tolerance at 90% of their predetermined peak work rate. Diaphragm function was assessed before and 15 and 30 min after exercise by measuring the twitch transdiaphragmatic pressure (Pdi,tw) response to bilateral anterolateral magnetic stimulation of the phrenic nerves. Ventilatory constraint was assessed by measuring the tidal flow volume responses to exercise in relation to the maximal flow volume envelope. Pdi,tw was not different from baseline at any time after exercise (unpotentiated Pdi,tw = 19.3 ± 5.6 cmH2O at baseline, 19.8 ± 5.0 cmH2O at 15 min after exercise, and 19.4 ± 5.7 cmH2O at 30 min after exercise; P = 0.16). During exercise, there was a sudden, sustained rise in operating lung volumes and an eightfold increase in the work of breathing. However, only two subjects showed expiratory flow limitation, and there was substantial capacity to increase both flow and volume (<50% of maximal breathing reserve). In conclusion, highly trained athletes with CSCI do not develop exercise-induced diaphragmatic fatigue and rarely reach mechanical ventilatory constraint

Engineering Cowpea Mosaic Virus RNA-2 into a Vector to Express Heterologous Proteins in Plants

AbstractA series of new cowpea mosaic virus (CPMV) RNA-2-based expression vectors were designed. The jellyfish green fluorescent protein (GFP) was introduced between the movement protein (MP) and the large (L) coat protein or downstream of the small (S) coat protein. Release of the GFP inserted between the MP and L proteins was achieved by creating artificial processing sites each side of the insert, either by duplicating the MP-L cleavage site or by introducing a sequence encoding the foot-and-mouth disease virus (FMDV) 2A catalytic peptide. Eight amino acids derived from the C-terminus of the MP and 14–19 amino acids from the N-terminus of the L coat protein were necessary for efficient processing of the artificial Gln/Met sites. Insertion of the FMDV 2A sequence at the C-terminus of the GFP resulted in a genetically stable construct, which produced particles containing about 10 GFP-2A-L fusion proteins. Immunocapture experiments indicated that some of the GFP is present on the virion surface. Direct fusion of GFP to the C-terminus of the S coat protein resulted in a virus which was barely viable. However, when the sequence of GFP was linked to the C-terminus by an active FMDV 2A sequence, a highly infectious construct was obtained

Stainless steel finned tube heat exchanger design for waste heat recovery

Around the world the implementation of heat recovery systems play an increasingly important role in the engineering industry. Recovered energy is utilised in production plants (especially in the food industry) and saves companies millions in expenses per year. Waste heat recovery associated with hydrocarbon combustion in the transport industry is identified as a significantly under-utilised energy resource. The aim of this project was to investigate the recovery of waste heat in a small scale system for the purpose of electrical conversion in order to serve as a secondary energy source. A theoretical analysis concerning the design and construction of the system, utilising researched theory and a control-volume-based simulation program of the recovery system, is presented. It was found that heat exchangers for the required duty are not readily available in South Africa. A high pressure, cross flow, stainless steel finned tube heat exchanger with a water side pressure rating of 2 MPa was therefore designed and constructed. By using the exhaust gases of a continuous combustion unit as an energy source and water as the working fluid, efficiencies of up to 74% in direct steam generation testing were obtained

Heat and fluid flow in a scraped-surface heat exchanger containing a fluid with temperature-dependent viscosity

Scraped-surface heat exchangers (SSHEs) are extensively used in a wide variety of industrial settings where the continuous processing of fluids and fluid-like materials is involved. The steady non-isothermal flow of a Newtonian fluid with temperature-dependent viscosity in a narrow-gap SSHE when a constant temperature difference is imposed across the gap between the rotor and the stator is investigated. The mathematical model is formulated and the exact analytical solutions for the heat and fluid flow of a fluid with a general dependence of viscosity on temperature for a general blade shape are obtained. These solutions are then presented for the specific case of an exponential dependence of viscosity on temperature. Asymptotic methods are employed to investigate the behaviour of the solutions in several special limiting geometries and in the limits of weak and strong thermoviscosity. In particular, in the limit of strong thermoviscosity (i.e., strong heating or cooling and/or strong dependence of viscosity on temperature) the transverse and axial velocities become uniform in the bulk of the flow with boundary layers forming either just below the blade and just below the stationary upper wall or just above the blade and just above the moving lower wall. Results are presented for the most realistic case of a linear blade which illustrate the effect of varying the thermoviscosity of the fluid and the geometry of the SSHE on the flow

An assessment of road-verge grass as a feedstock for farm-fed anaerobic digestion plants

Cuttings from road-verge grass could provide biomass for energy generation, but currently this potential is not exploited. This research assessed the technical, practical and financial feasibility of using grass harvested from road verges as a feedstock in farm-fed anaerobic digestion (AD) plants. The methane potential (191 mL CH4 gDM−1) and digestion characteristics of verge grass were similar to those of current farm feedstocks; indicating suitability for AD. Ensiling had no significant impact on the biomethane generated. Testing co-digestions of verge grass with current farm feedstocks showed enhanced methane yields, suggesting that verge grass could be a valuable addition to AD feedstock mixes. In a case study of the UK county of Lincolnshire, potential volumes and locations of verge grass biomass were estimated, with capacities and locations of existing AD plants, to assess the potential to supply practical grass volumes. Grass harvesting costs were modelled and compared with other feedstock costs. Finally, the attitudes of AD operators to using verge grass were investigated to understand whether a market for verge grass exists. In a small survey all operators were willing to use it as a feedstock and most were prepared to pay over the estimated harvesting cost. If verge grass was legally recognised as a waste product it could be attractive to AD operators especially where financial incentives to use waste feedstocks are in place. In rural areas, verge grass could be harvested and co-digested by existing farm-fed AD plants, potentially reducing the cost of road verge maintenance and increasing biodiversity

Geographical location influences the composition of the gut microbiota in wild house mice (Mus musculus domesticus) at a fine spatial scale.

The composition of the mammalian gut microbiota can be influenced by a multitude of environmental variables such as diet and infections. Studies investigating the effect of these variables on gut microbiota composition often sample across multiple separate populations and habitat types. In this study we explore how variation in the gut microbiota of the house mouse (Mus musculus domesticus) on the Isle of May, a small island off the east coast of Scotland, is associated with environmental and biological factors. Our study focuses on the effects of environmental variables, specifically trapping location and surrounding vegetation, as well as the host variables sex, age, body weight and endoparasite infection, on the gut microbiota composition across a fine spatial scale in a freely interbreeding population. We found that differences in gut microbiota composition were significantly associated with the trapping location of the host, even across this small spatial scale. Sex of the host showed a weak association with microbiota composition. Whilst sex and location could be identified as playing an important role in the compositional variation of the gut microbiota, 75% of the variation remains unexplained. Whereas other rodent studies have found associations between gut microbiota composition and age of the host or parasite infections, the present study could not clearly establish these associations. We conclude that fine spatial scales are important when considering gut microbiota composition and investigating differences among individuals