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The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.
Barramundi (Lates calcarifer) are a highly valued aquaculture species, and, as obligate carnivores, they have a demonstrated preference for dietary protein over lipid or starch to fuel energetic growth demands. In order to investigate how carnivorous fish regulate nutritional cues, we examined the metabolic effects of feeding two isoenergetic diets that contained different proportions of digestible protein or starch energy. Fish fed a high proportion of dietary starch energy had a higher proportion of liver SFA, but showed no change in plasma glucose levels, and few changes in the expression of genes regulating key hepatic metabolic pathways. Decreased activation of the mammalian target of rapamycin growth signalling cascade was consistent with decreased growth performance values. The fractional synthetic rate (lipogenesis), measured by TAG 2H-enrichment using 2H NMR, was significantly higher in barramundi fed with the starch diet compared with the protein diet (0·6 (se 0·1) v. 0·4 (se 0·1) % per d, respectively). Hepatic TAG-bound glycerol synthetic rates were much higher than other closely related fish such as sea bass, but were not significantly different (starch, 2·8 (se 0·3) v. protein, 3·4 (se 0·3) % per d), highlighting the role of glycerol as a metabolic intermediary and high TAG-FA cycling in barramundi. Overall, dietary starch significantly increased hepatic TAG through increased lipogenesis. Compared with other fish, barramundi possess a unique mechanism to metabolise dietary carbohydrates and this knowledge may define ways to improve performance of advanced formulated feeds.
Changes in respiratory pathogen testing can affect disease burden estimates. Using linked data, we describe changes in respiratory virus testing among children born in Western Australia in 1996–2012. We extracted data on respiratory specimens from these children from birth to age 9 years. We estimated testing rates by age, year, Aboriginal status and geographical location. Predictors of testing among children hospitalised at least once before their 10th birthday were identified using logistic regression. We compared detection methods for respiratory viruses from nasal/nasopharyngeal (NP) specimens by age and year. Of 83 199 virology testing records in 2000–2012, 80% were nasal/NP specimens. Infants aged <1 month had the highest testing rates. Testing rates in all children increased over the study period with considerable yearly fluctuations. Among hospitalised children, premature children <32 weeks gestation had over three times the odds of being tested (95% CI 3·47–4·13) than those born at term. Testing using molecular methods increased from 5% to 87% over the study period. Proportion of positive samples increased from 36·3% to 44·4% (P < 0·01); this change was greatest in children aged 2–9 years. These findings will assist in interpreting results from future epidemiology studies assessing the pathogen-specific burden of disease.
Australia's National Immunisation Program (NIP) provides free influenza vaccination for children at high risk of severe influenza; a pilot-funded programme for vaccine in all children aged 6 months to <5 years in one of eight states, has seen poor vaccine impact, related to recent vaccine safety concerns. This retrospective review examined influenza hospitalizations in children aged <16 years from three seasons (2011–2013) at two paediatric hospitals on opposite sides of the country. Comparisons of this cohort were made with state-based data on influenza-coded hospitalizations and national immunization register data on population-level immunization coverage. Of 740 hospitalizations, the majority were aged <5 years (476/740, 64%), and a substantial proportion (57%) involved healthy children, not currently funded for influenza vaccine. Intensive care unit admission occurred in 8·5%, and 1·5% of all children developed encephalitis. Use of antiviral therapy was uncommon (20·5%) and decreasing. Of those hospitalized, only 5·0% of at-risk children, who are currently eligible for free vaccine, and 0·7% of healthy children were vaccinated prior to hospitalization. This was consistent with low population-wide estimates of influenza vaccine uptake. It highlights the need to examine alternative strategies, such as universally funded paediatric influenza vaccination, to address disease burden in Australian children.
Volatile organic compounds (VOCs) can be hazardous to human health and can negatively impact the long-term stability of art objects. This research evaluated the VOC adsorbent properties of three materials commonly used in museums as humidity regulating or air filtering agents. Silica gel, activated charcoal, and zeolite powder, materials often placed in proximity to art objects, were analyzed using Thermal Desorption GC-MS to qualitatively identify adsorbed VOC’s from model environments. This research compared the adsorbing capabilities of these materials with a solid-phase micro-extraction (SPME) carboxen/polydimethyl siloxane fiber to frame their adsorbing powers. It was found that different adsorbents have very different ranges of adsorption for the chemicals tested. Silica gel powder and zeolite powder have the greatest sensitivity for acetic acid over a 24 hour exposure period. Zeolite powder and activated charcoal were more sensitive for identification of naphthalene. Silica gel powder proved to be the most sensitive adsorbent overall. This research discovered that the methods used to condition silica gel pellets for reuse need to be re-examined in light of fact they trap VOC’s, especially as it was observed that VOC’s desorb from the silica gel pellets under ambient conditions.
Our knowledge of glass production in ancient Egypt has been well augmented not only by the publication of recently excavated materials and glass workshops, but also by more recent materials analysis, and experiments of modern glass-makers attempting to reconstruct the production process of thin-walled core-formed glass vessels. The small but well preserved glass collection of the Freer Gallery of Art in Washington, D.C. was used to examine and study the technology and production of ancient Egyptian core-formed glass vessels. Previous study suggests that most of these vessels were produced in the 18th Dynasty in the 15th and 14th centuries BCE, while others date from the Hellenistic period and later. In an ongoing project we conducted computed radiography, x-ray fluorescence analysis and scanning electron microscopy on a selected group of vessels to understand further aspects of the ancient production process. This paper will provide an overview of our recent research.
Radiotherapy departments are having to work more efficiently to cope with increasing demand for radiotherapy resources. Radiotherapy treatment room efficiency may be increased by the introduction of hospital clothing as this negates the need for patient changing in the treatment room. However, studies have shown that hospital clothing can have a negative effect on patient dignity. It is therefore important to balance potential time saving with any detriment to patients.
This study examined the effect that hospital clothing had on the time patients spend in the treatment room and aimed to identify patients’ opinions of the clothing.
Materials and methods
Potential time saving was determined by covertly timing patients currently undergoing radiotherapy treatment as they entered and exited the treatment room. A total of 348 patients were timed in their own clothing and 341 were timed when they wore hospital clothing. The timings of these two groups were compared to determine whether hospital clothing saved treatment unit time. Patient opinions of the clothing were examined by issuing a short questionnaire, designed to gather ordinal data, at the end of their course of treatment. Questionnaires were issued only to patients who had worn hospital clothing in the radiotherapy department.
Introducing hospital clothing saved a significant amount of treatment room time and patients were generally positive about wearing the clothing.
It is suggested that hospital clothing is a welcome addition to the radiotherapy department to increase efficiency without detriment to patients.
Ensuring reproducibility in any radiotherapy technique is vital to ensure that a geometric miss does not occur. Patient position and comfort play a major part in the reproducibility of setups.
Purpose: To study the effect on accuracy of the introduction of a bellyboard to the existing prone technique used for radical radiotherapy treatment of prostate cancer.
Materials and Methods: Thirty patients were treated using the bellyboard in the standard method. Portal images were compared with those of a control group of patients who had treatment with no rigid immobilisation. Patients in both groups were males with prostate cancer, who underwent radical radiotherapy treatment. Images were analysed using anatomy matching, and deviations from the isocentre were noted.
Results: Statistical analysis of the results showed no statistical significance between the groups, though within the control group there were more deviations over 0.5 cm from the isocentre position than in the bellyboard group.
Conclusions: Introduction of the bellyboard was seen to be equivalent to the use of the control technique. When the deviations from isocentre position were evaluated for each group, the control group had more deviations over 0.5 cm than the bellyboard group.
The transit of a two-dimensional elastic fluid-filled capsule through a channel with a side branch is investigated numerically. The mathematical formulation allows for a capsule carried in a pressure-driven flow of fluid of generally different viscosity to that inside the capsule. Far upstream and downstream in the main channel, and downstream in the side branch, the fluid velocity profiles are assumed to adopt those of unidirectional Poiseuille flow with prescribed flow rates. The capsule boundary is treated as a two-dimensional elastic membrane developing elastic tensions and bending moments according to simple constitutive laws. A boundary-integral formulation allows for the explicit computation of the fluid pressures upstream and downstream of the branching. The novelty of the approach is the inclusion of a notional boundary at the entrance to the side branch, which avoids the need to collocate the channel ends. The deformation experienced by the capsule in the region of the junction is found to depend strongly on the branch angle. The deformation is ameliorated by increasing the membrane stiffness or lowering the viscosity of the suspending fluid relative to the encapsulated fluid. When a capsule exits the branch region, a distance of many decades of capsule diameters is required before the capsule relaxes to an equilibrium shape. Capsule residence times in the vicinity of the branch region can be considerable, depending on the line of approach into the junction and the capsule deformability. The path selection of a cell at a branch junction can depend crucially on capsule deformability: capsules with different elastic properties may follow different routes out of the junction in otherwise identical flow conditions.
The expansion rate of the Universe can potentially be measured using age-dating of Luminous Red Galaxies (LRGs). Here, we explore the validity of the assumptions implicit in this method using LRGs identified in the Millenium Simulation (MS). We use stellar population modelling and spectral synthesis to estimate the errors on ages that can be expected and discuss optimization of such an experiment. We find that H(z) using simulated galaxies from MS can be recovered with high accuracy. Using single stellar populations (SSPs) to age-date LRGs is not sufficient but if the MS star formation histories of galaxies are used, accurate ages are obtainable. We discuss an observing program to carry out this experiment using SALT (Southern African Large Telescope).
Two changes were observed in the acid phosphatase of macrophages that had ingested infective TRIC organisms: the proportion of extralysosomal enzyme rose, while the total amount in the cells fell. Both effects were directly related to the number of organisms ingested and increased with time. When macrophages were inoculated with more than 50 organisms per cell, changes were obvious within a few hours; with 2–10 organisms per cell changes were detectable only after 18 hr. or more. Enzyme appeared in the culture medium as the amount in the cells decreased. Ingestion of organisms killed by heat or treated with antibody did not induce such changes. In infected BHK-21 cells, no changes in acid phosphatase were detected at any stage of the developmental cycle of the organism.
Compression tests with varying loading rates were performed on  and  oriented small-scale bcc Mo and Nb pillars to determine the contribution of thermally activated screw dislocation motion during deformation. Calculated activation volumes were shown to be in the range of 2 - 9 b3 and by further examination were found to decrease with pillar diameter. This suggests that the kink-pair nucleation of screw dislocations is enhanced by surface effects in the micron and submicron range.
The capillary instability of a liquid thread containing a regular array of spherical particles along the centreline is considered with reference to microencapsulation. The thread interface may be clean or occupied by an insoluble surfactant. The main goal of the analysis is to illustrate the effect of the particle spacing on the growth rate of axisymmetric perturbations and identify the structure of the most unstable modes. A normal-mode linear stability analysis based on Fourier expansions for Stokes flow reveals that, at small particle separations, the interfacial profiles are nearly pure sinusoidal waves whose growth rate is nearly equal to that of a pure thread devoid of particles. Higher harmonics suddenly enter the normal modes for moderate and large particle separations, elevating the growth rates and yielding a stability diagram that consists of a sequence of superposed pure-thread lobes. A complementary numerical stability analysis based on the boundary integral formulation for Stokes flow reveals the strong stabilizing effect of particles whose radius is comparable to the thread radius. Numerical simulations of the finite-amplitude motion based on the boundary integral method demonstrate that thread breakup leads to particles coated with annular layers of different thicknesses.
Legionnaires' disease (LD) is caused by Legionella species, most of which live in water. The Mid-Atlantic region experienced a sharp rise in LD in 2003 coinciding with a period of record-breaking rainfall. To investigate a possible relationship, we analysed the association between monthly legionellosis incidence and monthly rainfall totals from January 1990 to December 2003 in five Mid-Atlantic states. Using negative binomial model a 1-cm increase in rainfall was associated with a 2·6% (RR 1·026, 95% CI 1·012–1·040) increase in legionellosis incidence. The average monthly rainfall from May to September 1990–2002 was 10·4 cm compared to 15·7 cm from May to September 2003. This change in rainfall corresponds to an increased risk for legionellosis of approximately 14·6% (RR 1·146, 95% CI 1·067–1·231). Legionellosis incidence increased during periods of increased rainfall; identification of mechanisms that increase exposure and transmission of Legionella during rainfall might lead to opportunities for prevention.
The effect of an insoluble surfactant on the stability of the core–annular flow of two immiscible fluids is investigated by a normal-mode linear analysis and by numerical simulations based on the immersed-interface method for axisymmetric perturbations. The results reveal that, although the Marangoni stress due to surfactant concentration variations is unable to initiate a new type of instability as in the case of two-dimensional two-layer channel flow, it does destabilize the interface by broadening the range of growing wavenumbers and by raising the growth rate of unstable perturbations. Numerical simulations for large-amplitude disturbances reveal that the surfactant plays an important role in determining the morphology of the interfacial structures developing in the nonlinear stages of the motion.
The effect of an insoluble surfactant on the stability of the gravity-driven flow of a liquid film down an inclined plane is investigated by a normal-mode analysis. Numerical solutions of the Orr–Sommerfeld equation reveal the occurrence of a stable Marangoni mode and a possibly unstable Yih mode, and demonstrate that the primary role of the surfactant is effectively to raise the critical Reynolds number at which instability is first encountered.