Diode-side-pumped Alexandrite slab lasers

We present the investigation of diode-side-pumping of Alexandrite slab lasers in a range of designs using linear cavity and grazing-incidence bounce cavity configurations. An Alexandrite slab laser cavity with double-pass side pumping produces 23.4 mJ free-running energy at 100 Hz rate with slope efficiency ~40% with respect to absorbed pump energy. In a slab laser with single-bounce geometry output power of 12.2 W is produced, and in a double-bounce configuration 6.5 W multimode and 4.5 W output in TEM00 mode is produced. These first results of slab laser and amplifier designs in this paper highlight some of the potential strategies for power and energy scaling of Alexandrite using diode-side-pumped Alexandrite slab architectures with future availability of higher power red diode pumping

Online and on course

Professor Geraint Thomas introduces the course he leads, which aims to expand research activity in the life sciences by enabling learners to develop and interpret advanced models for solving complex issue

Understanding Western Art through Culture

link_to_OA_fulltex

Temporal variability and social heterogeneity in disease transmission: The case of SARS in Hong Kong

The extent to which self-adopted or intervention-related changes in behaviors affect the course of epidemics remains a key issue for outbreak control. This study attempted to quantify the effect of such changes on the risk of infection in different settings, i.e., the community and hospitals. The 2002-2003 severe acute respiratory syndrome (SARS) outbreak in Hong Kong, where 27% of cases were healthcare workers, was used as an example. A stochastic compartmental SEIR (susceptible-exposed-infectious-removed) model was used: the population was split into healthcare workers, hospitalized people and general population. Super spreading events (SSEs) were taken into account in the model. The temporal evolutions of the daily effective contact rates in the community and hospitals were modeled with smooth functions. Data augmentation techniques and Markov chain Monte Carlo (MCMC) methods were applied to estimate SARS epidemiological parameters. In particular, estimates of daily reproduction numbers were provided for each subpopulation. The average duration of the SARS infectious period was estimated to be 9.3 days (±0.3 days). The model was able to disentangle the impact of the two SSEs from background transmission rates. The effective contact rates, which were estimated on a daily basis, decreased with time, reaching zero inside hospitals. This observation suggests that public health measures and possible changes in individual behaviors effectively reduced transmission, especially in hospitals. The temporal patterns of reproduction numbers were similar for healthcare workers and the general population, indicating that on average, an infectious healthcare worker did not infect more people than any other infectious person. We provide a general method to estimate time dependence of parameters in structured epidemic models, which enables investigation of the impact of control measures and behavioral changes in different settings. © 2009 Cori et al.published_or_final_versio

Label-free Raman spectroscopic imaging to extract morphological and chemical information from a formalin-fixed, paraffin-embedded rat colon tissue section.

Animal models and archived human biobank tissues are useful resources for research in disease development, diagnostics and therapeutics. For the preservation of microscopic anatomical features and to facilitate long-term storage, a majority of tissue samples are denatured by the chemical treatments required for fixation, paraffin embedding and subsequent deparaffinization. These aggressive chemical processes are thought to modify the biochemical composition of the sample and potentially compromise reliable spectroscopic examination useful for the diagnosis or biomarking. As a result, spectroscopy is often conducted on fresh/frozen samples. In this study, we provide an extensive characterization of the biochemical signals remaining in processed samples (formalin fixation and paraffin embedding, FFPE) and especially those originating from the anatomical layers of a healthy rat colon. The application of chemometric analytical methods (unsupervised and supervised) was shown to eliminate the need for tissue staining and easily revealed microscopic features consistent with goblet cells and the dense populations of cells within the mucosa, principally via strong nucleic acid signals. We were also able to identify the collagenous submucosa- and serosa- as well as the muscle-associated signals from the muscular regions and blood vessels. Applying linear regression analysis to the data, we were able to corroborate this initial assignment of cell and tissue types by confirming the biological origin of each layer by reference to a subset of authentic biomolecular standards. Our results demonstrate the potential of using label-free Raman microspectroscopy to obtain superior imaging contrast in FFPE sections when compared directly to conventional haematoxylin and eosin (H&E) staining

Influenza vaccination and hospitalisation in Elderly Health Centres.

1. A cohort of Elderly Health Centres was examined to determine whether influenza vaccination decreased hospitalisation and mortality. 2. In the influenza season, influenza vaccination reduced all-cause mortality by half and cardiorespiratory hospitalisation by a quarter. The extent to which influenza vaccination protects older people from serious morbidity and mortality needs to be confirmed in appropriately designed studies, so that scarce health care resources can be used effectivelypublished_or_final_versio

Clinical significance of medial vs lateral compartment patellofemoral osteoarthritis: cross-sectional analyses in an adult population with knee pain

Objective To determine the comparative prevalence, associations with selected patient characteristics, and clinical outcomes of medial and lateral compartment patellofemoral (PF) joint osteoarthritis (OA). Methods Information was collected by questionnaires, clinical assessment, and radiographs from 745 eligible community‐dwelling symptomatic adults age ≥50 years. PF joint space narrowing (JSN) and osteophytes were scored from skyline radiographs using the Osteoarthritis Research Society International atlas. Multilevel models were used to assess associations of compartmental PF joint OA with age, sex, body mass index (BMI) and varus–valgus malalignment, while median regression was used to examine associations with clinical outcomes (current pain intensity on a numeric rating scale [0–10] and the function subscale of the Western Ontario and McMaster Universities Osteoarthritis Index [0–68]). Results Isolated lateral PF joint OA was more common than isolated medial PF joint OA, particularly at higher severity thresholds. Irrespective of severity threshold, age (≥2 odds ratio [OR] 1.19 [95% confidence interval (95% CI) 1.12, 1.26]), BMI (≥2 OR 1.15 [95% CI 1.07, 1.24]), and valgus malalignment (≥2 OR 2.58 [95% CI 1.09, 6.07]) were associated with increased odds of isolated lateral JSN, but isolated medial JSN was only associated with age (≥2 OR 1.20 [95% CI 1.14, 1.27]). The pattern of association was less clear for PF joint osteophytes. Isolated lateral PF joint OA, defined by JSN or osteophytes, was associated with higher pain scores than isolated medial PF joint OA, but these differences were modest and were not significant. A similar pattern of association was seen for functional limitation but only when PF joint OA was defined by JSN. Conclusion Isolated lateral PF joint OA is more common than isolated medial PF joint OA, and it is more consistently associated with established OA risk factors. It is also associated with higher, but clinically nonsignificant, pain and function scores than isolated medial PF joint OA, particularly when PF joint OA is defined using JSN

HYPERPHOSPHATEMIA IN END STAGE RENAL DISEASE: PREVALENCE AND PATIENTS CHARACTERISTICS OF MULTIETHNIC POPULATION OF UNITED ARAB EMIRATES

Objective: Hyperphosphatemia is significantly associated with increased mortality among end stage renal disease (ESRD) patients on hemodialysis. There is paucity of data on hyperphosphatemia in ESRD patients of the multiethnic population of United Arab Emirates (UAE). The study aimed to investigate the prevalence and characteristics of hyperphosphatemia in ESRD patients of the multiethnic population of UAE undergoing maintenance hemodialysis.Methods: Adults ESRD patients undergoing maintenance hemodialysis for more than six months at the study site were included. Demographic, clinical and biological data of the patients were collected. Patient characteristics were compared as per the serum phosphate level, between patients with or without hyperphosphatemia. Univariate and multivariate logistic regression analyses were carried out to identify the predictors of hyperphosphatemia.Results: Hyperphosphatemia was present in 73.8% of the study population, while 31.3% presented with high calcium-phosphate product. Univariate logistic analysis revealed that hyperphosphatemia was inversely correlated with age, hemoglobin, serum calcium, and hypertensive nephropathy as cause of renal disease, and positively correlated with female gender, expatriate status, body mass index (BMI), higher number of comorbidities, calcium-phosphate product and parathyroid hormone (PTH). Multivariate logistic regression model revealed that only age, BMI, hemoglobin and PTH independently correlated with hyperphosphatemia.Conclusion: We report a high prevalence of hyperphosphatemia in multiethnic study population undergoing maintenance hemodialysis at a secondary care hospital in UAE. In this study population, only age, BMI, hemoglobin and PTH were identified as independent predictors of hyperphosphatemia