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51.
52.
Carly Rich Marco Geraci Lucy Griffiths Francesco Sera Carol Dezateux Mario Cortina-Borja 《PloS one》2013,8(6)
Background
When using accelerometers to measure physical activity, researchers need to determine whether subjects have worn their device for a sufficient period to be included in analyses. We propose a minimum wear criterion using population-based accelerometer data, and explore the influence of gender and the purposeful inclusion of children with weekend data on reliability.Methods
Accelerometer data obtained during the age seven sweep of the UK Millennium Cohort Study were analysed. Children were asked to wear an ActiGraph GT1M accelerometer for seven days. Reliability coefficients(r) of mean daily counts/minute were calculated using the Spearman-Brown formula based on the intraclass correlation coefficient. An r of 1.0 indicates that all the variation is between- rather than within-children and that measurement is 100% reliable. An r of 0.8 is often regarded as acceptable reliability. Analyses were repeated on data from children who met different minimum daily wear times (one to 10 hours) and wear days (one to seven days). Analyses were conducted for all children, separately for boys and girls, and separately for children with and without weekend data.Results
At least one hour of wear time data was obtained from 7,704 singletons. Reliability increased as the minimum number of days and the daily wear time increased. A high reliability (r = 0.86) and sample size (n = 6,528) was achieved when children with ≥ two days lasting ≥10 hours/day were included in analyses. Reliability coefficients were similar for both genders. Purposeful sampling of children with weekend data resulted in comparable reliabilities to those calculated independent of weekend wear.Conclusion
Quality control procedures should be undertaken before analysing accelerometer data in large-scale studies. Using data from children with ≥ two days lasting ≥10 hours/day should provide reliable estimates of physical activity. It’s unnecessary to include only children with accelerometer data collected during weekends in analyses. 相似文献53.
Diogo Jurelevicius Vanessa Marques Alvarez Raquel Peixoto Alexandre S. Rosado Lucy Seldin 《PloS one》2013,8(6)
The alkane monooxygenase AlkB, which is encoded by the alkB gene, is a key enzyme involved in bacterial alkane degradation. To study the alkB gene within bacterial communities, researchers need to be aware of the variations in alkB nucleotide sequences; a failure to consider the sequence variations results in the low representation of the diversity and richness of alkane-degrading bacteria. To minimize this shortcoming, the use of a combination of three alkB-targeting primers to enhance the detection of the alkB gene in previously isolated alkane-degrading bacteria was proposed. Using this approach, alkB-related PCR products were detected in 79% of the strains tested. Furthermore, the chosen set of primers was used to study alkB richness and diversity in different soils sampled in Carmópolis, Brazil and King George Island, Antarctica. The DNA extracted from the different soils was PCR amplified with each set of alkB-targeting primers, and clone libraries were constructed, sequenced and analyzed. A total of 255 alkB phylotypes were detected. Venn diagram analyses revealed that only low numbers of alkB phylotypes were shared among the different libraries derived from each primer pair. Therefore, the combination of three alkB-targeting primers enhanced the richness of alkB phylotypes detected in the different soils by 45% to 139%, when compared to the use of a single alkB-targeting primer. In addition, a dendrogram analysis and beta diversity comparison of the alkB composition showed that each of the sampling sites studied had a particular set of alkane-degrading bacteria. The use of a combination of alkB primers was an efficient strategy for enhancing the detection of the alkB gene in cultivable bacteria and for better characterizing the distribution of alkane-degrading bacteria in different soil environments. 相似文献
54.
Lucy A. Jury Brett Sitzlar Sirisha Kundrapu Jennifer L. Cadnum Kim M. Summers Christine P. Muganda Abhishek Deshpande Ajay K. Sethi Curtis J. Donskey 《PloS one》2013,8(7)
Background
Recent reports suggest that community-associated Clostridium difficile infection (CDI) (i.e., no healthcare facility admission within 90 days) may be increasing in frequency. We hypothesized that outpatient clinics could be an important source for acquisition of community-associated CDI.Methods
We performed a 6-month prospective study of CDI patients to determine frequency of and risk factors for skin and environmental shedding during outpatient visits and to derive a prediction rule for positive cultures. We performed a point–prevalence culture survey to assess the frequency of C. difficile contamination in outpatient settings and evaluated the frequency of prior outpatient visits in patients with community-associated CDI.Results
Of 67 CDI patients studied, 54 (81%) had 1 or more outpatient visits within 12 weeks after diagnosis. Of 44 patients cultured during outpatient visits, 14 (32%) had skin contamination and 12 (27%) contaminated environmental surfaces. Decreased mobility, fecal incontinence, and treatment with non-CDI antibiotics were associated with positive cultures, whereas vancomycin taper therapy was protective. In patients not on CDI therapy, a prediction rule including incontinence or decreased mobility was 90% sensitive and 79% specific for detection of spore shedding. Of 84 clinic and emergency department rooms cultured, 12 (14%) had 1 or more contaminated environmental sites. For 33 community-associated CDI cases, 31 (94%) had an outpatient visit during the 12 weeks prior to onset of diarrhea.Conclusions
Patients with recent CDI present a significant risk for transmission of spores during outpatient visits. The outpatient setting may be an underappreciated source of community-associated CDI cases. 相似文献55.
Kate Bramham Carlos E. Poli-de-Figueiredo Paul T. Seed Annette L. Briley Lucilla Poston Andrew H. Shennan Lucy C. Chappell 《PloS one》2013,8(10)
Objectives
To evaluate occurrence of adverse maternal and perinatal outcomes with different thresholds of proteinuria (300-499mg and ≥500mg/24 hours) in pre-eclamptic women, comparing outcomes against women with chronic and gestational hypertension.Design
Secondary analysis of the Vitamins in Pre-Eclampsia Trial.Setting
25 UK hospitals in ten geographical areas.Population
946 women with pre-existing risk factors for pre-eclampsia.Methods
Women with pre-eclampsia and proteinuria 300-499mg/24h (PE300, referent group, n=60) or proteinuria ≥500 mg/24h (PE500, n=161) were compared with two groups of non-proteinuric women with chronic hypertension (CHT, n=615) or gestational hypertension (GH, n=110).Main Outcome Measures
Maternal: progression to severe hypertension. Perinatal: small for gestational age (SGA) <5th centile, gestation at delivery.Results
Severe hypertension occurred more frequently in PE500 (35%) and PE300 (27%) than CHT (5.9%; P≤0.01) and GH (10%; p≤0.001). Gestation at delivery was earlier in PE500 (33.2w) than PE300 (37.3w; P≤0.001), and later in CHT (38.3w; P≤0.05) and GH (39.1w; P≤0.001). SGA infants were more frequent in PE300 (32%) than in CHT (13.3%; P≤0.001) and GH (16.5%; P≤0.05). Women in PE500 were more likely to have a caesarean section than PE300 (78% vs. 48%; P≤0.001), and to receive magnesium sulphate (17% vs. 1.7%, P≤0.05).Conclusion
Women with PE300 have complication rates above those of women managed as out-patients (GH and CHT), meriting closer surveillance and confirming 300 mg/d as an appropriate threshold for determining in-patient management. Adverse perinatal outcomes are higher still in women with PE500. 相似文献56.
David C. Bartholomew Paulo R. L. Bittencourt Antonio C. L. da Costa Lindsay F. Banin Patrícia de Britto Costa Sarah I. Coughlin Tomas F. Domingues Leandro V. Ferreira André Giles Maurizio Mencuccini Lina Mercado Raquel C. Miatto Alex Oliveira Rafael Oliveira Patrick Meir Lucy Rowland 《Plant, cell & environment》2020,43(10):2380-2393
The response of small understory trees to long-term drought is vital in determining the future composition, carbon stocks and dynamics of tropical forests. Long-term drought is, however, also likely to expose understory trees to increased light availability driven by drought-induced mortality. Relatively little is known about the potential for understory trees to adjust their physiology to both decreasing water and increasing light availability. We analysed data on maximum photosynthetic capacity (Jmax, Vcmax), leaf respiration (Rleaf), leaf mass per area (LMA), leaf thickness and leaf nitrogen and phosphorus concentrations from 66 small trees across 12 common genera at the world's longest running tropical rainfall exclusion experiment and compared responses to those from 61 surviving canopy trees. Small trees increased Jmax, Vcmax, Rleaf and LMA (71, 29, 32, 15% respectively) in response to the drought treatment, but leaf thickness and leaf nutrient concentrations did not change. Small trees were significantly more responsive than large canopy trees to the drought treatment, suggesting greater phenotypic plasticity and resilience to prolonged drought, although differences among taxa were observed. Our results highlight that small tropical trees have greater capacity to respond to ecosystem level changes and have the potential to regenerate resilient forests following future droughts. 相似文献
57.
Commander Lucy Elizabeth Merino-Martín Luis Elliott Carole P. Miller Ben P. Dixon Kingsley Stevens Jason 《Plant and Soil》2020,457(1-2):113-129
Plant and Soil - Understanding limitations to plant recruitment is a key element in devising effective restoration of semi-arid ecosystems: only when these limitations are identified can management... 相似文献
58.
Wenhui Wang Lucy A. Muir Muhui Zhang Ran Zhao Jingqiang Tan Xu Chen 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2020,53(3):396-408
Three-dimensionally preserved pyritic internal moulds of the Late Ordovician graptolites Appendispinograptus leptothecalis and Styracograptus chiai from the Upper Ordovician Wufeng Formation of the Daheba section, Hunan Province, South China, were imaged by micro-CT. The distinctive pea-shaped pits/dimples aligned in a zigzag line arising from the second/third thecal pair on the tubarium in these species are interpreted as the surface expression of the junction between the lateral thecal walls and the thickened internal cross-bars that support the nema. The relations between different internal structures such as the nema, median septum, aboral lists, interthecal septa and cross-bars are summarized, and examples of these supporting systems in different taxa are illustrated. The presence of isolated cross-bars in different diplograptid tubarium may suggest that they have evolved as a result of constructional restrictions. 相似文献
59.
Co-administration of Selenium with Inorganic Mercury Alters the Disposition of Mercuric Ions in Rats
Orr Sarah E. George Hannah S. Barnes Mary C. Mathis Taylor N. Joshee Lucy Barkin Jennifer Kiefer Adam M. Seney Caryn S. Bridges Christy C. 《Biological trace element research》2020,195(1):187-195
Biological Trace Element Research - Mercury (Hg) is a common environmental toxicant to which humans are exposed regularly through occupational and dietary means. Although selenium supplementation... 相似文献
60.
Lucy Wentworth Justin V. Meyers Sheeba Alam Andrew J. Russ M. Suresh Clifford S. Cho 《Cancer immunology, immunotherapy : CII》2013,62(1):149-159
We have previously observed that in vivo exposure to growing melanoma tumors fundamentally alters activated T cell homeostasis by suppressing the ability of naïve T cells to undergo antigen-driven proliferative expansion. We hypothesized that exposure of T cells in later stages of differentiation to melanoma would have similar suppressive consequences. C57BL/6 mice were inoculated with media or syngeneic B16F10 melanoma tumors 8 or 60 days after infection with lymphocytic choriomeningitis virus (LCMV), and splenic populations of LCMV-specific T cells were quantified using flow cytometry 18 days after tumor inoculation. Inoculation with melanoma on post-infection day 8 potentiated the contraction of previously activated T cells. This enhanced contraction was associated with increased apoptotic susceptibility among T cells from tumor-bearing mice. In contrast, inoculation with melanoma on post-infection day 60 did not affect the ability of previously established memory T cells to maintain themselves in stable numbers. In addition, the ability of previously established memory T cells to respond to LCMV challenge was unaffected by melanoma. Following adoptive transfer into melanoma-bearing mice, tumor-specific memory T cells were significantly more effective at controlling melanoma growth than equivalent numbers of tumor-specific effector T cells. These observations suggest that memory T cells are uniquely resistant to suppressive influences exerted by melanoma on activated T cell homeostasis; these findings may have implications for T cell–based cancer immunotherapy. 相似文献