66 research outputs found

    The First Direct Detection of Kirkwood Transitions in Concentrated Aqueous Electrolytes using Small Angle X-ray Scattering

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    Ion-ion correlations, screening, and equilibrium bulk structure in various concentrated electrolytes are investigated using synchrotron small angle X-ray scattering (SAXS), theory, and molecular simulation. Utilizing SAXS measurements we provide estimates of the Kirkwood Transition (KT) for a variety of aqueous electrolytes (NaCl, CaCl2_2, SrCl2_2, and ErCl3_3). The KT may be defined as the concentration above which the ion-ion correlations cease to decay exponentially with a single length scale given by the Debye length λD\lambda_{\rm D} and develop an additional length scale, d=2π/Q0d=2\pi/Q_0 that reflects the formation of local domains of charge. Theoretical models of the KT have been known for decades for highly idealized models of electrolytes, but experimental verification of KT in real electrolytes has yet to be confirmed. Herein, we provide consistent theoretical and experimental estimates of both the inverse screening lengths a0a_0 and inverse domain size, Q0Q_0 for the aforementioned electrolyte systems. Taken together, a0a_0 and Q0Q_0 are known descriptors of the KT and provide a view into the complexity of ion-ion interaction beyond the well-accepted Debye-H\"{u}ckel limit. Our findings suggest a picture of interaction for real electrolytes that is more general than that found in idealized models that is manifest in the precise form of the non-local response function that we estimate through the interpretation of the experimental SAXS signal. Importantly, the additional complexity of describing ion-ion interaction of real electrolytes will implicate the short-range ion-ion interactions that can only be computed via molecular simulation and provide a quantitative approach to describe electrolyte phenomena beyond Debye-H\"{u}ckel theory.Comment: 3

    Force-time characteristics of the countermovement jump: analyzing the curve in Excel

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    Increased popularity in the utilization of force plates to measure countermovement jumps (cmjs) for performance monitoring warrants the need for strength and conditioning coaches and sport scientists to better under-stand its force-time characteristics and the calculation of its associated variables. this article aims to provide information on how to understand and analyze the force-time curve of cmjs in microsoft excel, thus providing practitioners an inexpensive and accessible alternative to readily avail-able software on the market

    Coherent Detector Arrays for Millimeter and Submillimeter Astronomy

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    Progress in many areas of astronomy requires large-area surveys and observations of extended objects. This includes the cosmic microwave background, nearby galaxies, the Milky Way, and regions of star-forming regions within our galaxy. The ability to carry out such studies is critically dependent on the development of affordable high-sensitivity focal plane arrays, for both spectral line and continuum observations. We discuss a program for the next decade to develop such technology for ground-based and spacebased millimeter and submillimeter astronomy. Appropriate technologies exist, but significant effort is required to make the transition from simply replicating individual pixels to approaching focal plane array design in an integrated fashion from feeds to spectrometers for spectral analysis. This advance is essential to realize the full potential of major new ground-based, suborbital, and future space facilities, and is relevant to the RMS and EOS panels. The recommended budget for this activity is $65M

    Male synthetic sling versus artificial urinary sphincter trial for men with urodynamic stress incontinence after prostate surgery (MASTER): Study protocol for a randomised controlled trial

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    © 2018 The Author(s). Background: Stress urinary incontinence (SUI) is a frequent adverse effect for men undergoing prostate surgery. A large proportion (around 8% after radical prostatectomy and 2% after transurethral resection of prostate (TURP)) are left with severe disabling incontinence which adversely effects their quality of life and many are reliant on containment measures such as pads (27% and 6% respectively). Surgery is currently the only option for active management of the problem. The overwhelming majority of surgeries for persistent bothersome SUI involve artificial urinary sphincter (AUS) insertion. However, this is expensive, and necessitates manipulation of a pump to enable voiding. More recently, an alternative to AUS has been developed - a synthetic sling for men which elevates the urethra, thus treating SUI. This is thought, by some, to be less invasive, more acceptable and less expensive than AUS but clear evidence for this is lacking. The MASTER trial aims to determine whether the male synthetic sling is non-inferior to implantation of the AUS for men who have SUI after prostate surgery (for cancer or benign disease), judged primarily on clinical effectiveness but also considering relative harms and cost-effectiveness. Methods/design: Men with urodynamic stress incontinence (USI) after prostate surgery, for whom surgery is judged appropriate, are the target population. We aim to recruit men from secondary care urological centres in the UK NHS who carry out surgery for post-prostatectomy incontinence. Outcomes will be assessed by participant-completed questionnaires and 3-day urinary bladder diaries at baseline, 6, 12 and 24 months. The 24-h urinary pad test will be used at baseline as an objective assessment of urine loss. Clinical data will be completed at the time of surgery to provide details of the operative procedures, complications and resource use in hospital. At 12 months, men will also have a clinical review to evaluate the results of surgery (including another 24-h pad test) and to identify problems or need for further treatment. Discussion: A robust examination of the comparative effectiveness of the male synthetic sling will provide high-quality evidence to determine whether or not it should be adopted widely in the NHS

    Hyponatremia and hospital outcomes among patients with pneumonia: a retrospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>Community-acquired (CAP) and nosocomial pneumonias contribute substantially to morbidity and hospital resource utilization. Hyponatremia, occurring in >1/4 of patients with CAP, is associated with greater disease severity and worsened outcomes.</p> <p>Methods</p> <p>To explore how hyponatremia is associated with outcomes in hospitalized patients with pneumonia, we analyzed a large administrative database with laboratory component from January 2004 to December 2005. Hyponatremia was defined as at least two [Na<sup>+</sup>] < 135 mEq/L within 24 hours of admission value.</p> <p>Results</p> <p>Of 7,965 patients with pneumonia, 649 (8.1%) with hyponatremia were older (72.4 ± 15.7 vs. 68.0 ± 22.0, p < 0.01), had a higher mean Deyo-Charlson Comorbidity Index Score (1.7 ± 1.7 vs. 1.6 ± 1.6, p = 0.02), and higher rates of ICU (10.0% vs. 6.3%, p < 0.001) and MV (3.9% vs. 2.3%, p = 0.01) in the first 48 hours of hospitalization than patients with normal sodium. Hyponatremia was associated with an increased ICU (6.3 ± 5.6 vs. 5.3 ± 5.1 days, p = 0.07) and hospital lengths of stay (LOS, 7.6 ± 5.3 vs. 7.0 ± 5.2 days, p < 0.001) and a trend toward increased hospital mortality (5.4% vs. 4.0%, p = 0.1). After adjusting for confounders, hyponatremia was associated with an increased risk of ICU (OR 1.58, 95% CI 1.20–2.08), MV (OR 1.75 95% CI 1.13–2.69), and hospital death (OR 1.3, 95% CI 0.90–1.87) and with increases of 0.8 day to ICU and 0.3 day to hospital LOS, and over $1,300 to total hospital costs.</p> <p>Conclusion</p> <p>Hyponatremia is common among hospitalized patients with pneumonia and is associated with worsened clinical and economic outcomes. Studies in this large population are needed to explore whether prompt correction of [Na<sup>+</sup>] may impact these outcomes.</p

    Antiferromagnetic metal phase in an electron-doped rare-earth nickelate

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    Long viewed as passive elements, antiferromagnetic materials have emerged as promising candidates for spintronic devices due to their insensitivity to external fields and potential for high-speed switching. Recent work exploiting spin and orbital effects has identified ways to electrically control and probe the spins in metallic antiferromagnets, especially in noncollinear or noncentrosymmetric spin structures. The rare earth nickelate NdNiO3 is known to be a noncollinear antiferromagnet where the onset of antiferromagnetic ordering is concomitant with a transition to an insulating state. Here, we find that for low electron doping, the magnetic order on the nickel site is preserved while electronically a new metallic phase is induced. We show that this metallic phase has a Fermi surface that is mostly gapped by an electronic reconstruction driven by the bond disproportionation. Furthermore, we demonstrate the ability to write to and read from the spin structure via a large zero-field planar Hall effect. Our results expand the already rich phase diagram of the rare-earth nickelates and may enable spintronics applications in this family of correlated oxides.Comment: 25 pages, 4 figure

    Synthetic sling or artificial urinary sphincter for men with urodynamic stress incontinence after prostate surgery: The MASTER non-inferiority RCT

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    BACKGROUND: Stress urinary incontinence is common in men after prostate surgery and can be difficult to improve. Implantation of an artificial urinary sphincter is the most common surgical procedure for persistent stress urinary incontinence, but it requires specialist surgical skills, and revisions may be necessary. In addition, the sphincter is relatively expensive and its operation requires adequate patient dexterity. New surgical approaches include the male synthetic sling, which is emerging as a possible alternative. However, robust comparable data, derived from randomised controlled trials, on the relative safety and efficacy of the male synthetic sling and the artificial urinary sphincter are lacking. OBJECTIVE: We aimed to compare the clinical effectiveness and cost-effectiveness of the male synthetic sling with those of the artificial urinary sphincter surgery in men with persistent stress urinary incontinence after prostate surgery. DESIGN: This was a multicentre, non-inferiority randomised controlled trial, with a parallel non-randomised cohort and embedded qualitative component. Randomised controlled trial allocation was carried out by remote web-based randomisation (1 : 1), minimised on previous prostate surgery (radical prostatectomy or transurethral resection of the prostate), radiotherapy (or not, in relation to prostate surgery) and centre. Surgeons and participants were not blind to the treatment received. Non-randomised cohort allocation was participant and/or surgeon preference. SETTING: The trial was set in 28 UK urological centres in the NHS. PARTICIPANTS: Participants were men with urodynamic stress incontinence after prostate surgery for whom surgery was deemed appropriate. Exclusion criteria included previous sling or artificial urinary sphincter surgery, unresolved bladder neck contracture or urethral stricture after prostate surgery, and an inability to give informed consent or complete trial documentation. INTERVENTIONS: We compared male synthetic sling with artificial urinary sphincter. MAIN OUTCOME MEASURES: The clinical primary outcome measure was men's reports of continence (assessed from questions 3 and 4 of the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form) at 12 months post randomisation (with a non-inferiority margin of 15%). The primary economic outcome was cost-effectiveness (assessed as the incremental cost per quality-adjusted life-year at 24 months post randomisation). RESULTS: In total, 380 men were included in the randomised controlled trial (n = 190 in each group), and 99 out of 100 men were included in the non-randomised cohort. In terms of continence, the male sling was non-inferior to the artificial urinary sphincter (intention-to-treat estimated absolute risk difference -0.034, 95% confidence interval -0.117 to 0.048; non-inferiority p = 0.003), indicating a lower success rate in those randomised to receive a sling, but with a confidence interval excluding the non-inferiority margin of -15%. In both groups, treatment resulted in a reduction in incontinence symptoms (as measured by the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form). Between baseline and 12 months' follow-up, the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form score fell from 16.1 to 8.7 in the male sling group and from 16.4 to 7.5 in the artificial urinary sphincter group (mean difference for the time point at 12 months 1.30, 95% confidence interval 0.11 to 2.49; p = 0.032). The number of serious adverse events was small (male sling group, n = 8; artificial urinary sphincter group, n = 15; one man in the artificial urinary sphincter group experienced three serious adverse events). Quality-of-life scores improved and satisfaction was high in both groups. Secondary outcomes that showed statistically significant differences favoured the artificial urinary sphincter over the male sling. Outcomes of the non-randomised cohort were similar. The male sling cost less than the artificial sphincter but was associated with a smaller quality-adjusted life-year gain. The incremental cost-effectiveness ratio for male slings compared with an artificial urinary sphincter suggests that there is a cost saving of £425,870 for each quality-adjusted life-year lost. The probability that slings would be cost-effective at a £30,000 willingness-to-pay threshold for a quality-adjusted life-year was 99%. LIMITATIONS: Follow-up beyond 24 months is not available. More specific surgical/device-related pain outcomes were not included. CONCLUSIONS: Continence rates improved from baseline, with the male sling non-inferior to the artificial urinary sphincter. Symptoms and quality of life significantly improved in both groups. Men were generally satisfied with both procedures. Overall, secondary and post hoc analyses favoured the artificial urinary sphincter over the male sling. FUTURE WORK: Participant reports of any further surgery, satisfaction and quality of life at 5-year follow-up will inform longer-term outcomes. Administration of an additional pain questionnaire would provide further information on pain levels after both surgeries. TRIAL REGISTRATION: This trial is registered as ISRCTN49212975. FUNDING: This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 36. See the NIHR Journals Library website for further project information

    A Conserved Supergene Locus Controls Colour Pattern Diversity in Heliconius Butterflies

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    We studied whether similar developmental genetic mechanisms are involved in both convergent and divergent evolution. Mimetic insects are known for their diversity of patterns as well as their remarkable evolutionary convergence, and they have played an important role in controversies over the respective roles of selection and constraints in adaptive evolution. Here we contrast three butterfly species, all classic examples of Müllerian mimicry. We used a genetic linkage map to show that a locus, Yb, which controls the presence of a yellow band in geographic races of Heliconius melpomene, maps precisely to the same location as the locus Cr, which has very similar phenotypic effects in its co-mimic H. erato. Furthermore, the same genomic location acts as a “supergene”, determining multiple sympatric morphs in a third species, H. numata. H. numata is a species with a very different phenotypic appearance, whose many forms mimic different unrelated ithomiine butterflies in the genus Melinaea. Other unlinked colour pattern loci map to a homologous linkage group in the co-mimics H. melpomene and H. erato, but they are not involved in mimetic polymorphism in H. numata. Hence, a single region from the multilocus colour pattern architecture of H. melpomene and H. erato appears to have gained control of the entire wing-pattern variability in H. numata, presumably as a result of selection for mimetic “supergene” polymorphism without intermediates. Although we cannot at this stage confirm the homology of the loci segregating in the three species, our results imply that a conserved yet relatively unconstrained mechanism underlying pattern switching can affect mimicry in radically different ways. We also show that adaptive evolution, both convergent and diversifying, can occur by the repeated involvement of the same genomic regions

    Insights into hominid evolution from the gorilla genome sequence.

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    Gorillas are humans' closest living relatives after chimpanzees, and are of comparable importance for the study of human origins and evolution. Here we present the assembly and analysis of a genome sequence for the western lowland gorilla, and compare the whole genomes of all extant great ape genera. We propose a synthesis of genetic and fossil evidence consistent with placing the human-chimpanzee and human-chimpanzee-gorilla speciation events at approximately 6 and 10 million years ago. In 30% of the genome, gorilla is closer to human or chimpanzee than the latter are to each other; this is rarer around coding genes, indicating pervasive selection throughout great ape evolution, and has functional consequences in gene expression. A comparison of protein coding genes reveals approximately 500 genes showing accelerated evolution on each of the gorilla, human and chimpanzee lineages, and evidence for parallel acceleration, particularly of genes involved in hearing. We also compare the western and eastern gorilla species, estimating an average sequence divergence time 1.75 million years ago, but with evidence for more recent genetic exchange and a population bottleneck in the eastern species. The use of the genome sequence in these and future analyses will promote a deeper understanding of great ape biology and evolution

    Genomic Hotspots for Adaptation: The Population Genetics of Müllerian Mimicry in the Heliconius melpomene Clade

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    Wing patterning in Heliconius butterflies is a longstanding example of both Müllerian mimicry and phenotypic radiation under strong natural selection. The loci controlling such patterns are “hotspots” for adaptive evolution with great allelic diversity across different species in the genus. We characterise nucleotide variation, genotype-by-phenotype associations, linkage disequilibrium, and candidate gene expression at two loci and across multiple hybrid zones in Heliconius melpomene and relatives. Alleles at HmB control the presence or absence of the red forewing band, while alleles at HmYb control the yellow hindwing bar. Across HmYb two regions, separated by ∼100 kb, show significant genotype-by-phenotype associations that are replicated across independent hybrid zones. In contrast, at HmB a single peak of association indicates the likely position of functional sites at three genes, encoding a kinesin, a G-protein coupled receptor, and an mRNA splicing factor. At both HmYb and HmB there is evidence for enhanced linkage disequilibrium (LD) between associated sites separated by up to 14 kb, suggesting that multiple sites are under selection. However, there was no evidence for reduced variation or deviations from neutrality that might indicate a recent selective sweep, consistent with these alleles being relatively old. Of the three genes showing an association with the HmB locus, the kinesin shows differences in wing disc expression between races that are replicated in the co-mimic, Heliconius erato, providing striking evidence for parallel changes in gene expression between Müllerian co-mimics. Wing patterning loci in Heliconius melpomene therefore show a haplotype structure maintained by selection, but no evidence for a recent selective sweep. The complex genetic pattern contrasts with the simple genetic basis of many adaptive traits studied previously, but may provide a better model for most adaptation in natural populations that has arisen over millions rather than tens of years
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