156 research outputs found

    Bacterial Colonization of Toys in Neonatal Intensive Care Cots

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    Objectives. To investigate the bacteria and fungi contaminating toys in neonatal intensive care unit (NICU) cots, the colonization rates, and factors that influence them. Methods. A cross-sectional, longitudinal bacteriologic survey of all toys in the cots of infants in an NICU. All the toys in an infant's cot were cultured weekly for 4 weeks. Data were collected on the infant's postnatal age, the type of cot, whether humidity was added, characteristics of the toy, and any infant infections. Results. Over the 4-week period, there were 86 cultures from 34 toys of 19 infants. Bacteria were grown from 84/86 (98%): 84 of the cultures grew coagulase-negative Staphylococcus, 50 Micrococcus sp, 21 Bacillus sp, 13 methicillin-resistant Staphylococcus aureus, 12 diphtheroids, 4 group B streptococcus, 3 S aureus, 3 nonhemolytic streptococci, 3 group D streptococci, 4 -hemolytic streptococci, and 2 coliforms. None grew fungi. The colonization rate did not differ with cot type, presence of humidity, size of the toy, toy fiber length, or the fluffiness score. Eight (42%) of the infants had positive blood culture results and 5/8 of the isolates (63%) were of the same type as that colonizing their corresponding toy. Implications. With time, all the toys in NICU cots became colonized with bacteria. Many were potentially pathogenic. Toys may be reservoirs for potential infantile nosocomial sepsis

    Inhibition of ammonia monooxygenase from ammonia oxidising archaea by linear and aromatic alkynes

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    Ammonia monooxygenase (AMO) is a key nitrogen-transforming enzyme belonging to the same copper-dependent membrane monooxygenase family (CuMMO) as the particulate methane monooxygenase (pMMO). The AMO from ammonia-oxidizing archaea (AOA) is very divergent from both the AMO of ammonia-oxidizing bacteria (AOB) and the pMMO from methanotrophs, and little is known about the structure or substrate range of the archaeal AMO. This study compares inhibition by C 2 to C 8 linear 1-alkynes of AMO from two phylogenetically distinct strains of AOA, " Candidatus Nitrosocosmicus franklandus" C13 and " Candidatus Nitrosotalea sinensis" Nd2, with AMO from Nitrosomonas europaea and pMMO from Methylococcus capsulatus (Bath). An increased sensitivity of the archaeal AMO to short-chain-length alkynes (≤C 5) appeared to be conserved across AOA lineages. Similarities in C 2 to C 8 alkyne inhibition profiles between AMO from AOA and pMMO from M. capsulatus suggested that the archaeal AMO has a narrower substrate range than N. europaea AMO. Inhibition of AMO from " Ca Nitrosocosmicus franklandus" and N. europaea by the aromatic alkyne phenylacetylene was also investigated. Kinetic data revealed that the mechanisms by which phenylacetylene inhibits " Ca Nitrosocosmicus franklandus" and N. europaea are different, indicating differences in the AMO active site between AOA and AOB. Phenylacetylene was found to be a specific and irreversible inhibitor of AMO from " Ca Nitrosocosmicus franklandus," and it does not compete with NH 3 for binding at the active site. IMPORTANCE Archaeal and bacterial ammonia oxidizers (AOA and AOB, respectively) initiate nitrification by oxidizing ammonia to hydroxylamine, a reaction catalyzed by ammonia monooxygenase (AMO). AMO enzyme is difficult to purify in its active form, and its structure and biochemistry remain largely unexplored. The bacterial AMO and the closely related particulate methane monooxygenase (pMMO) have a broad range of hydrocarbon cooxidation substrates. This study provides insights into the AMO of previously unstudied archaeal genera, by comparing the response of the archaeal AMO, a bacterial AMO, and pMMO to inhibition by linear 1-alkynes and the aromatic alkyne, phenylacetylene. Reduced sensitivity to inhibition by larger alkynes suggests that the archaeal AMO has a narrower hydrocarbon substrate range than the bacterial AMO, as previously reported for other genera of AOA. Phenylacetylene inhibited the archaeal and bacterial AMOs at different thresholds and by different mechanisms of inhibition, highlighting structural differences between the two forms of monooxygenase

    Deep three-dimensional solid-state qubit arrays with long-lived spin coherence

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    Nitrogen-vacancy centers (NVCs) in diamond show promise for quantum computing, communication, and sensing. However, the best current method for entangling two NVCs requires that each one is in a separate cryostat, which is not scalable. We show that single NVCs can be laser written 6–15-µm deep inside of a diamond with spin coherence times that are an order of magnitude longer than previous laser-written NVCs and at least as long as naturally occurring NVCs. This depth is suitable for integration with solid immersion lenses or optical cavities and we present depth-dependent T2 measurements. 200 000 of these NVCs would fit into one diamond

    Laser writing of individual atomic defects in a crystal with near-unity yield

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    Atomic defects in wide band gap materials show great promise for development of a new generation of quantum information technologies, but have been hampered by the inability to produce and engineer the defects in a controlled way. The nitrogen-vacancy (NV) color center in diamond is one of the foremost candidates, with single defects allowing optical addressing of electron spin and nuclear spin degrees of freedom with potential for applications in advanced sensing and computing. Here we demonstrate a method for the deterministic writing of individual NV centers at selected locations with high positioning accuracy using laser processing with online fluorescence feedback. This method provides a new tool for the fabrication of engineered materials and devices for quantum technologies and offers insight into the diffusion dynamics of point defects in solids.Comment: 16 pages, 8 figure

    Measuring and Replicating the 1-20 um Energy Distributions of the Coldest Brown Dwarfs: Rotating, Turbulent and Non-Adiabatic Atmospheres

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    Cold, low-mass, field brown dwarfs are important for constraining the terminus of the stellar mass function, and also for optimizing atmospheric studies of exoplanets. In 2020 new model grids for such objects were made available: Sonora-Bobcat and ATMO 2020. Also, new candidate cold brown dwarfs were announced, and new spectroscopic observations at lambda ~4.8 um were published. In this paper we present new infrared photometry for some of the coldest brown dwarfs, and put the new data and models together to explore the properties of these objects. We reconfirm the importance of mixing in these atmospheres, which leads to CO and NH_3 abundances that differ by orders of magnitude from chemical equilibrium values. We also demonstrate that the new models retain the known factor >~3 discrepancy with observations at 2 <~ lambda um <~ 4, for brown dwarfs cooler than 600 K. We show that the entire 1 <~ lambda um <~ 20 energy distribution of six brown dwarfs with 260 <= T_eff K <= 475 can be well reproduced, for the first time, by model atmospheres which include dis-equilibrium chemistry as well as a photospheric temperature gradient which deviates from the standard radiative/convective equilibrium value. This change to the pressure-temperature profile is not unexpected for rotating and turbulent atmospheres which are subject to diabatic processes. A limited grid of modified-adiabat model colors is generated, and used to estimate temperatures and metallicities for the currently known Y dwarfs. A compilation of the photometric data used here is given in the Appendix.Comment: 40 pages which includes 16 Figures and 10 Tables. The Journal publication will include data behind the Figures for Figures 5, 8 and 9, and a machine readable version of Table 1

    Long Spin Coherence and Relaxation Times in Nanodiamonds Milled from Polycrystalline 12^{12}C Diamond

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    The negatively charged nitrogen-vacancy centre (NV−^-) in diamond has been utilized in a wide variety of sensing applications. The centre's long spin coherence and relaxation times (T2∗T_2^*, T2T_2 and T1T_1) at room temperature are crucial to this, as they often limit sensitivity. Using NV−^- centres in nanodiamonds allows for operations in environments inaccessible to bulk diamond, such as intracellular sensing. We report long spin coherence and relaxation times at room temperature for single NV−^- centres in isotopically-purified polycrystalline ball-milled nanodiamonds. Using a spin-locking pulse sequence, we observe spin coherence times, T2T_2, up 786 ±\pm 200 μ\mus. We also measure T2∗T_2^* times up to 2.06 ±\pm 0.24 μ\mus and T1T_1 times up to 4.32 ±\pm 0.60 ms. Scanning electron microscopy and atomic force microscopy measurements show that the diamond containing the NV−^{-} centre with the longest T1T_1 time is smaller than 100 nm. EPR measurements give an Ns_{s}0^{0} concentration of 0.15 ±\pm 0.02 ppm for the nanodiamond sample.Comment: 13 pages, 3 figure

    Clinical effectiveness and cost-effectiveness of collaborative care for depression in UK primary care (CADET): a cluster randomised controlled trial.

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    BACKGROUND: Collaborative care is effective for depression management in the USA. There is little UK evidence on its clinical effectiveness and cost-effectiveness. OBJECTIVE: To determine the clinical effectiveness and cost-effectiveness of collaborative care compared with usual care in the management of patients with moderate to severe depression. DESIGN: Cluster randomised controlled trial. SETTING: UK primary care practices (n = 51) in three UK primary care districts. PARTICIPANTS: A total of 581 adults aged ≥ 18 years in general practice with a current International Classification of Diseases, Tenth Edition depressive episode, excluding acutely suicidal people, those with psychosis, bipolar disorder or low mood associated with bereavement, those whose primary presentation was substance abuse and those receiving psychological treatment. INTERVENTIONS: Collaborative care: 14 weeks of 6-12 telephone contacts by care managers; mental health specialist supervision, including depression education, medication management, behavioural activation, relapse prevention and primary care liaison. Usual care was general practitioner standard practice. MAIN OUTCOME MEASURES: Blinded researchers collected depression [Patient Health Questionnaire-9 (PHQ-9)], anxiety (General Anxiety Disorder-7) and quality of life (European Quality of Life-5 Dimensions three-level version), Short Form questionnaire-36 items) outcomes at 4, 12 and 36 months, satisfaction (Client Satisfaction Questionnaire-8) outcomes at 4 months and treatment and service use costs at 12 months. RESULTS: In total, 276 and 305 participants were randomised to collaborative care and usual care respectively. Collaborative care participants had a mean depression score that was 1.33 PHQ-9 points lower [n = 230; 95% confidence interval (CI) 0.35 to 2.31; p = 0.009] than that of participants in usual care at 4 months and 1.36 PHQ-9 points lower (n = 275; 95% CI 0.07 to 2.64; p = 0.04) at 12 months after adjustment for baseline depression (effect size 0.28, 95% CI 0.01 to 0.52; odds ratio for recovery 1.88, 95% CI 1.28 to 2.75; number needed to treat 6.5). Quality of mental health but not physical health was significantly better for collaborative care at 4 months but not at 12 months. There was no difference for anxiety. Participants receiving collaborative care were significantly more satisfied with treatment. Differences between groups had disappeared at 36 months. Collaborative care had a mean cost of £272.50 per participant with similar health and social care service use between collaborative care and usual care. Collaborative care offered a mean incremental gain of 0.02 (95% CI -0.02 to 0.06) quality-adjusted life-years (QALYs) over 12 months at a mean incremental cost of £270.72 (95% CI -£202.98 to £886.04) and had an estimated mean cost per QALY of £14,248, which is below current UK willingness-to-pay thresholds. Sensitivity analyses including informal care costs indicated that collaborative care is expected to be less costly and more effective. The amount of participant behavioural activation was the only effect mediator. CONCLUSIONS: Collaborative care improves depression up to 12 months after initiation of the intervention, is preferred by patients over usual care, offers health gains at a relatively low cost, is cost-effective compared with usual care and is mediated by patient activation. Supervision was by expert clinicians and of short duration and more intensive therapy may have improved outcomes. In addition, one participant requiring inpatient treatment incurred very significant costs and substantially inflated our cost per QALY estimate. Future work should test enhanced intervention content not collaborative care per se. TRIAL REGISTRATION: Current Controlled Trials ISRCTN32829227. FUNDING: This project was funded by the Medical Research Council (MRC) (G0701013) and managed by the National Institute for Health Research (NIHR) on behalf of the MRC-NIHR partnership

    Soil, senescence and exudate utilisation: characterisation of the Paragon var. spring bread wheat root microbiome

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    Background: Conventional methods of agricultural pest control and crop fertilisation are unsustainable. To meet growing demand, we must find ecologically responsible means to control disease and promote crop yields. The root-associated microbiome can aid plants with disease suppression, abiotic stress relief, and nutrient bioavailability. The aim of the present work was to profile the community of bacteria, fungi, and archaea associated with the wheat rhizosphere and root endosphere in different conditions. We also aimed to use 13CO2 stable isotope probing (SIP) to identify microbes within the root compartments that were capable of utilising host-derived carbon. Results: Metabarcoding revealed that community composition shifted significantly for bacteria, fungi, and archaea across compartments. This shift was most pronounced for bacteria and fungi, while we observed weaker selection on the ammonia oxidising archaea-dominated archaeal community. Across multiple soil types we found that soil inoculum was a significant driver of endosphere community composition, however, several bacterial families were identified as core enriched taxa in all soil conditions. The most abundant of these were Streptomycetaceae and Burkholderiaceae. Moreover, as the plants senesce, both families were reduced in abundance, indicating that input from the living plant was required to maintain their abundance in the endosphere. Stable isotope probing showed that bacterial taxa within the Burkholderiaceae family, among other core enriched taxa such as Pseudomonadaceae, were able to use root exudates, but Streptomycetaceae were not. Conclusions: The consistent enrichment of Streptomycetaceae and Burkholderiaceae within the endosphere, and their reduced abundance after developmental senescence, indicated a significant role for these families within the wheat root microbiome. While Streptomycetaceae did not utilise root exudates in the rhizosphere, we provide evidence that Pseudomonadaceae and Burkholderiaceae family taxa are recruited to the wheat root community via root exudates. This deeper understanding crop microbiome formation will enable researchers to characterise these interactions further, and possibly contribute to ecologically responsible methods for yield improvement and biocontrol in the future

    Higher serum vitamin D3 levels are associated with better cognitive test performance in patients with Alzheimer's disease

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    Background/Aims: Recent studies suggest that vitamin D metabolites may be important for preserving cognitive function via specific neuroprotective effects. No large studies have examined the association between vitamin D status and cognition. Methods: In this cross-sectional study, we analyzed the serum 25-hydroxyvitamin D3levels and Mini-Mental State Examination (MMSE) test scores of 225 older outpatients who were diagnosed as having probable Alzheimer's disease (AD). In addition to the 25-hydroxyvitamin D3levels, we analyzed the serum vitamin B1, B6and B12levels. Results: An association was found between MMSE test scores and serum 25-hydroxyvitamin D3levels, with a β-coefficient of 0.05 (p = 0.01). Vitamin-D-sufficient patients had significantly higher MMSE scores as compared to vitamin-D-insufficient ones. No association was found with the other serum vitamin levels. Conclusions: These data support the idea that a relationship exists between vitamin D status and cognition in patients with probable AD. However, given the cross-sectional design of this study, no causality can be concluded. Further prospective studies are needed to specify the contribution of vitamin D status to the onset and course of cognitive decline and AD. Copyrigh
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