2,310 research outputs found

    Spatial confinement of muonium atoms

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    We report the achievement of spatial confinement of muonium atoms (the bound state of a positive muon and an electron). Muonium emitted into vacuum from mesoporous silica reflects between two SiO2_2 confining surfaces separated by 1 mm. From the data, one can extract that the reflection probability on the confining surfaces kept at 100 K is about 90% and the reflection process is well described by a cosine law. This technique enables new experiments with this exotic atomic system and is a very important step towards a measurement of the 1S-2S transition frequency using continuous wave laser spectroscopy.Comment: 5 pages, 6 figure

    LC-MS analysis to determine the biodistribution of a polymer coated ilomastat ocular implant

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    Ilomastat is a matrix metalloproteinase inhibitor (MMPi) that has shown the potential to inhibit scarring (fibrosis) by mediating healing after injury or surgery. A long lasting ocular implantable pharmaceutical formulation of ilomastat is being developed to mediate the healing process to prevent scarring after glaucoma filtration surgery. The ilomastat implant was coated with water permeable and biocompatible phosphoryl choline polymer (PC1059) displayed extended slow release of ilomastat in vitro and in vivo. The ocular distribution of ilomastat from the implant in rabbits at day 30 post surgery was determined by the extraction of ilomastat and its internal standard marimastat from the ocular tissues, plasma, aqueous humour and vitreous fluid followed by capillary-flow liquid chromatography (cap-LC), the column effluent was directed into a triple quadrupole mass spectrometer operating in product scan mode. The lower limits of quantification (LLOQs) were 0.3 pg/μL for ocular fluids and plasma, and 3 pg/mg for ocular tissues. The extraction recoveries were 90-95% for ilomastat and its internal standard from ocular tissues. Ilomastat was found in ocular fluids and tissues at day 30 after surgery. The level of ilomastat was 18 times higher in the aqueous humour than vitreous humour. The concentration ranking of ilomastat in the ocular tissues was sclera > bleb conjunctiva > conjunctiva (rest of the eye) > cornea. Mass spectrometry analysis to confirm the presence of ilomastat in the ocular tissues and fluids at day 30 post-surgery establishes the extended release of ilomastat can be achieved in vivo, which is crucial information for optimisation of the ilomastat coated implant

    The descriptive epidemiology of accelerometer-measured physical activity in older adults.

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    BACKGROUND: Objectively measured physical activity between older individuals and between populations has been poorly described. We aimed to describe and compare the variation in accelerometry data in older UK (EPIC-Norfolk) and American (NHANES) adults. METHODS: Physical activity was measured by uniaxial accelerometry in 4,052 UK (49-91 years) and 3459 US older adults (49-85 years). We summarized physical activity as volume (average counts/minute), its underlying intensity distribution, and as time spent 809 counts/minute is used 18.7% of people reached the 30 min/day threshold. By comparison, 2.5% and 9.5% of American older adults accumulated activity at these levels, respectively. CONCLUSION: As assessed by objectively measured physical activity, the majority of older adults in this UK study did not meet current activity guidelines. Older adults in the UK were more active overall, but also spent more time being sedentary than US adults.This work was supported by programme grants from the Medical Research Council [G9502233; G0401527] and Cancer Research UK [C864/A8257]. A grant from Research into Ageing [262] funded the 3rd health check clinic. KW is supported by a British Heart Foundation Intermediate Basic Science Research Fellowship [FS/12/58/29709], and AJMC, SJG, NJW, and SB are supported by MRC programme grants [MC_UU_12015/3 and MC_UU_12015/4].This is the final version of the article. It was first available from BioMed Central via http://dx.doi.org/10.1186/s12966-015-0316-

    Cross Sectional Associations between Socio-Demographic Factors and Cognitive Performance in an Older British Population: The European Investigation of Cancer in Norfolk (EPIC-Norfolk) Study

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    BACKGROUND\textbf{BACKGROUND}: Cognition covers a range of abilities, such as memory, response time and language, with tests assessing either specific or generic aspects. However differences between measures may be observed within the same individuals. OBJECTIVE\textbf{OBJECTIVE}: To investigate the cross-sectional association of cognitive performance and socio-demographic factors using different assessment tools across a range of abilities in a British cohort study. METHODS\textbf{METHODS}: Participants of the European Prospective Investigation of Cancer (EPIC) in Norfolk Study, aged 48-92 years, underwent a cognitive assessment between 2006 and 2011 (piloted between 2004 and 2006) and were investigated over a different domains using a range of cognitive tests. RESULTS\textbf{RESULTS}: Cognitive measures were available on 8584 men and women. Though age, sex, education and social class were all independently associated with cognitive performance in multivariable analysis, different associations were observed for different cognitive tests. Increasing age was associated with increased risk of a poor performance score in all of the tests, except for the National Adult Reading Test (NART), an assessment of crystallized intelligence. Compared to women, men were more likely to have had poor performance for verbal episodic memory, Odds Ratio, OR = 1.99 (95% Confidence Interval, 95% CI 1.72, 2.31), attention OR = 1.62, (95% CI 1.39, 1.88) and prospective memory OR = 1.46, (95% CI 1.29, 1.64); however, no sex difference was observed for global cognition, OR = 1.07 (95%CI 0.93, 1.24). The association with education was strongest for NART, and weakest for processing speed. CONCLUSION\textbf{CONCLUSION}: Age, sex, education and social class were all independently associated with performance on cognitive tests assessing a range of different domains. However, the magnitude of associations of these factors with different cognitive tests differed. The varying relationships seen across different tests may help explain discrepancies in results reported in the current literature, and provides insights into influences on cognitive performance in later life.The infrastructure for this study was supported by the Medical Research Council, UK http://www.mrc.ac.uk/ (Ref: G0401527) and Cancer Research UK http://www.cancerresearchuk.org/ (CRUK, Ref: C864/A8257). The clinic for EPIC-Norfolk 3 was funded by Research into Ageing, now known as Age UK http://www.ageuk.org.uk/ (Grant Ref: 262). The pilot phase was supported by MRC (Ref: G9502233) and CRUK (Ref: C864/A2883). KK received the above funding. FEM Is supported by MRC (Ref: U105292687)

    muCool: A novel low-energy muon beam for future precision experiments

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    Experiments with muons (μ+\mu^{+}) and muonium atoms (μ+e\mu^{+}e^{-}) offer several promising possibilities for testing fundamental symmetries. Examples of such experiments include search for muon electric dipole moment, measurement of muon g2g-2 and experiments with muonium from laser spectroscopy to gravity experiments. These experiments require high quality muon beams with small transverse size and high intensity at low energy. At the Paul Scherrer Institute, Switzerland, we are developing a novel device that reduces the phase space of a standard μ+\mu^{+} beam by a factor of 101010^{10} with 10310^{-3} efficiency. The phase space compression is achieved by stopping a standard μ+\mu^{+} beam in a cryogenic helium gas. The stopped μ+\mu^{+} are manipulated into a small spot with complex electric and magnetic fields in combination with gas density gradients. From here, the muons are extracted into the vacuum and into a field-free region. Various aspects of this compression scheme have been demonstrated. In this article the current status will be reported.Comment: 8 pages, 5 figures, TCP 2018 conference proceeding

    Alcohol Consumption and Incident Cataract Surgery in Two Large UK Cohorts

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    PURPOSE: To examine the association of alcohol consumption and type of alcoholic beverage with incident cataract surgery in two large cohorts. DESIGN: Longitudinal observational study PARTICIPANTS: We included 469,387 participants of UK Biobank with a mean age of 56 years, and 23,162 participants of EPIC-Norfolk with a mean age of 59 years. METHODS: Self-reported alcohol consumption at baseline was ascertained by a touchscreen questionnaire in UK Biobank and a food-frequency questionnaire in EPIC-Norfolk. Cases were defined as participants undergoing cataract surgery in either eye as ascertained via data linkage to National Health Service procedure statistics. We excluded participants with cataract surgery up to 1 year after the baseline assessment visit or those with self-reported cataract at baseline. Cox proportional hazards models were used to examine the associations of alcohol consumption with incident cataract surgery, adjusted for age, sex, ethnicity, Townsend deprivation index, body mass index, smoking and diabetes status. MAIN OUTCOME MEASURES: Incident cataract surgery RESULTS: There were 19,011 (mean cohort follow-up of 95 months) and 4,573 (mean cohort follow-up of 193 months) incident cases of cataract surgery in UK Biobank and EPIC-Norfolk, respectively. Compared to non-drinkers, drinkers were less likely to undergo cataract surgery in UK Biobank (HR 0.89, 95% CI 0.85-0.93) and EPIC-Norfolk (HR 0.90, 95% CI 0.84-0.97) after adjusting for covariables. Among alcohol consumers, greater alcohol consumption was associated with a reduced risk of undergoing cataract surgery in EPIC-Norfolk (P<0.001), while a U-shaped association was observed in the UK Biobank. Compared with non-drinkers, sub-group analysis by type of alcohol beverage showed the strongest protective association with wine consumption; the risk of incident cataract surgery was 23% and 14% lower among those in the highest category of wine consumption in EPIC-Norfolk and UK Biobank, respectively. CONCLUSION: Our findings suggest a lower risk of undergoing cataract surgery with low to moderate alcohol consumption. The association was particularly apparent with wine consumption. We cannot exclude the possibility of residual confounding and further studies are required to determine whether this association is causal in nature

    Muonium emission into vacuum from mesoporous thin films at cryogenic temperatures

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    We report on Muonium (Mu) emission into vacuum following {\mu}+ implantation in mesoporous thin SiO2 films. We obtain a yield of Mu into vacuum of (38\pm4)% at 250 K temperature and (20\pm4)% at 100 K for 5 keV {\mu}+ implantation energy. From the implantation energy dependence of the Mu vacuum yield we determine the Mu diffusion constants in these films: D250KMu = (1.6 \pm 0.1) \times 10-4 cm2/s and D100KMu = (4.2\pm0.5)\times10-5 cm2/s. Describing the diffusion process as quantum mechanical tunneling from pore-to-pore, we reproduce the measured temperature dependence T^3/2 of the diffusion constant. We extract a potential barrier of (-0.3 \pm 0.1) eV which is consistent with our computed Mu work-function in SiO2 of [-0.3,-0.9] eV. The high Mu vacuum yield even at low temperatures represents an important step towards next generation Mu spectroscopy experiments.Comment: 5 pages, 5 Figure

    Associations between daily sitting time and the combinations of lifestyle risk factors in men

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    Background: Understanding the reciprocal role that multiple problematic behaviours play in men's health is important for intervention delivery and for reducing the healthcare burden. Data regarding the concurrence of problematic health behaviours is currently limited but offers insights into risk profiles, and should now include total time spent sitting/day. Methods: Self-reported data on lifestyle health behaviours was collected from 232 men aged ≥18 years who engaged in a men's health promotion programme delivered by 16 English Premier League Clubs. Results: Men at risk due to high sitting display multiple concurrent lifestyle risk factors, 88.6% displayed at least two ancillary risk factors and were three times more likely to report ≥2 lifestyle risk factors (OR. =3.13, 95% confidence interval (CI). =1.52-6.42) than those with low sitting risk. Significant differences in the mean number of risk factors reported between those participants in the higher risk (2.43. ±. 0.90) and lower risk (2.13. ±. 0.96) sitting categories were also found (P=0.015). Conclusions: Hard-to-reach men displayed multiple problematic concurrent behaviours, strongly linked to total sitting time. © 2012 WPMH GmbH

    The Accuracy and Reliability of Crowdsource Annotations of Digital Retinal Images

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    PURPOSE: Crowdsourcing is based on outsourcing computationally intensive tasks to numerous individuals in the online community who have no formal training. Our aim was to develop a novel online tool designed to facilitate large-scale annotation of digital retinal images, and to assess the accuracy of crowdsource grading using this tool, comparing it to expert classification. METHODS: We used 100 retinal fundus photograph images with predetermined disease criteria selected by two experts from a large cohort study. The Amazon Mechanical Turk Web platform was used to drive traffic to our site so anonymous workers could perform a classification and annotation task of the fundus photographs in our dataset after a short training exercise. Three groups were assessed: masters only, nonmasters only and nonmasters with compulsory training. We calculated the sensitivity, specificity, and area under the curve (AUC) of receiver operating characteristic (ROC) plots for all classifications compared to expert grading, and used the Dice coefficient and consensus threshold to assess annotation accuracy. RESULTS: In total, we received 5389 annotations for 84 images (excluding 16 training images) in 2 weeks. A specificity and sensitivity of 71% (95% confidence interval [CI], 69%-74%) and 87% (95% CI, 86%-88%) was achieved for all classifications. The AUC in this study for all classifications combined was 0.93 (95% CI, 0.91-0.96). For image annotation, a maximal Dice coefficient (∼0.6) was achieved with a consensus threshold of 0.25. CONCLUSIONS: This study supports the hypothesis that annotation of abnormalities in retinal images by ophthalmologically naive individuals is comparable to expert annotation. The highest AUC and agreement with expert annotation was achieved in the nonmasters with compulsory training group. TRANSLATIONAL RELEVANCE: The use of crowdsourcing as a technique for retinal image analysis may be comparable to expert graders and has the potential to deliver timely, accurate, and cost-effective image analysis

    Mendelian Randomisation Study of Childhood BMI and Early Menarche

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    To infer the causal association between childhood BMI and age at menarche, we performed a mendelian randomisation analysis using twelve established “BMI-increasing” genetic variants as an instrumental variable (IV) for higher BMI. In 8,156 women of European descent from the EPIC-Norfolk cohort, height was measured at age 39–77 years; age at menarche was self-recalled, as was body weight at age 20 years, and BMI at 20 was calculated as a proxy for childhood BMI. DNA was genotyped for twelve BMI-associated common variants (in/near FTO, MC4R, TMEM18, GNPDA2, KCTD15, NEGR1, BDNF, ETV5, MTCH2, SEC16B, FAIM2 and SH2B1), and for each individual a “BMI-increasing-allele-score” was calculated by summing the number of BMI-increasing alleles across all 12 loci. Using this BMI-increasing-allele-score as an instrumental variable for BMI, each 1 kg/m2 increase in childhood BMI was predicted to result in a 6.5% (95% CI: 4.6–8.5%) higher absolute risk of early menarche (before age 12 years). While mendelian randomisation analysis is dependent on a number of assumptions, our findings support a causal effect of BMI on early menarche and suggests that increasing prevalence of childhood obesity will lead to similar trends in the prevalence of early menarche
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