229 research outputs found

    Separation of Parallel Encoded Complex-Valued Slices (SPECS) From A Single Complex-Valued Aliased Coil Image

    Get PDF
    Purpose Achieving a reduction in scan time with minimal inter-slice signal leakage is one of the significant obstacles in parallel MR imaging. In fMRI, multiband-imaging techniques accelerate data acquisition by simultaneously magnetizing the spatial frequency spectrum of multiple slices. The SPECS model eliminates the consequential inter-slice signal leakage from the slice unaliasing, while maintaining an optimal reduction in scan time and activation statistics in fMRI studies. Materials and Methods When the combined k-space array is inverse Fourier reconstructed, the resulting aliased image is separated into the un-aliased slices through a least squares estimator. Without the additional spatial information from a phased array of receiver coils, slice separation in SPECS is accomplished with acquired aliased images in shifted FOV aliasing pattern, and a bootstrapping approach of incorporating reference calibration images in an orthogonal Hadamard pattern. Result The aliased slices are effectively separated with minimal expense to the spatial and temporal resolution. Functional activation is observed in the motor cortex, as the number of aliased slices is increased, in a bilateral finger tapping fMRI experiment. Conclusion The SPECS model incorporates calibration reference images together with coefficients of orthogonal polynomials into an un-aliasing estimator to achieve separated images, with virtually no residual artifacts and functional activation detection in separated images

    An epic redemption: Re-reading some aberrant eleventh- century bodies

    Get PDF
    The text of the Junius 11 manuscript and the illustrations accompanying it are marked by an apparent discord, whereby the ecclesiastical nature of the work often seems threatened by the eroticism of the images. This thesis sets out to explain the disjunction, not by eliding it but rather showing it to be highly significant. To uncover the attitudes prevailing towards the corporeal (both erotic and numinous), the analysis undertakes a close examination of late tenth-/early eleventh-century conceptions of the body, especially those informed by the discourses of the Church. Such discourses frequently did pose the body in erotic formations, but in most of these it is possible to demonstrate multiple frameworks of social control being applied to them to determine correct meaning. The Junius Eve, however, does not conform to such structuralist paradigms. Her erotic subversion is driven by something beyond, even antithetical to, expositions of exterior power advanced by, for example, Michel Foucault or Judith Butler. To compensate for such structuralist lack, this thesis advances a psychoanalytic inflexion to develop a fusion that resolves the otherwise incongruous eroticism in the Junius Eve. The result is an Eve that completely subverts the text in a celebration of the libidinal

    4D In-Situ Microscopy of Aerosol Filtration in a Wall Flow Filter

    Get PDF
    The transient nature of the internal pore structure of particulate wall flow filters, caused by the continuous deposition of particulate matter, makes studying their flow and filtration characteristics challenging. In this article we present a new methodology and first experimental demonstration of time resolved in-situ synchrotron micro X-ray computed tomography (micro-CT) to study aerosol filtration. We directly imaged in 4D (3D plus time) pore scale deposits of TiO2 nanoparticles (nominal mean primary diameter of 25 nm) with a pixel resolution of 1.6 μm. We obtained 3D tomograms at a rate of ∼1 per minute. The combined spatial and temporal resolution allows us to observe pore blocking and filling phenomena as they occur in the filter’s pore space. We quantified the reduction in filter porosity over time, from an initial porosity of 0.60 to a final porosity of 0.56 after 20 min. Furthermore, the penetration depth of particulate deposits and filtration rate was quantified. This novel image-based method offers valuable and statistically relevant insights into how the pore structure and function evolves during particulate filtration. Our data set will allow validation of simulations of automotive wall flow filters. Evolutions of this experimental design have potential for the study of a wide range of dry aerosol filters and could be directly applied to catalysed automotive wall flow filters

    The Prediction of isothermal cyclic plasticity in 7175-T7351 aluminium alloy with particular emphasis on thermal ageing effects

    Get PDF
    Rapid thermal ageing has been observed in the literature for certain aerospace aluminium alloys under conditions which are foreseeable in their intended component applications. While several experimental programs have explored this phenomenon in the laboratory, efforts to incorporate these effects in unified constitutive models have, to date, been lacking. In the present work, a modified elastic-viscoplastic material model has been fitted to 7175-T7351 aluminium alloy data under fully-reversed uniaxial (strain-controlled) isothermal loading conditions at 160 °C and 200 °C. These temperatures were chosen in order to represent nominal and extreme (but still operationally relevant) conditions experienced by aero-engine gearbox components. The modified elastic-viscoplastic model is able to accurately predict the hysteresis loops of the strain-controlled fatigue data of each sample at 160 °C and 200 °C. Additionally, it was found that the isotropic hardening can be effectively de-coupled into material ageing and mechanical softening components

    Risk factors for genital infections in people initiating SGLT2 inhibitors and their impact on discontinuation

    Get PDF
    Introduction: To identify risk factors, absolute risk, and impact on treatment discontinuation of genital infections with sodium-glucose co-transporter-2 inhibitors (SGLT2i). Research design and methods: We assessed the relationship between baseline characteristics and genital infection in 21 004 people with type 2 diabetes initiating SGLT2i and 55 471 controls initiating dipeptidyl peptidase-4 inhibitors (DPP4i) in a UK primary care database. We assessed absolute risk of infection in those with key risk factors and the association between early genital infection and treatment discontinuation. Results: Genital infection was substantially more common in those treated with SGLT2i (8.1% within 1 year) than DPP4i (1.8%). Key predictors of infection with SGLT2i were female sex (HR 3.64; 95% CI 3.23 to 4.11) and history of genital infection; <1 year before initiation (HR 4.38; 3.73 to 5.13), 1–5 years (HR 3.04; 2.64 to 3.51), and >5 years (HR 1.79; 1.55 to 2.07). Baseline HbA1c was not associated with infection risk for SGLT2i, in contrast to DPP4i where risk increased with higher HbA1c. One-year absolute risk of genital infection with SGLT2i was highest for those with a history of prior infection (females 23.7%, males 12.1%), compared with those without (females 10.8%, males 2.7%). Early genital infection was associated with a similar discontinuation risk for SGLT2i (HR 1.48; 1.21–1.80) and DPP4i (HR 1.58; 1.21–2.07). Conclusions: Female sex and history of prior infection are simple features that can identify subgroups at greatly increased risk of genital infections with SGLT2i therapy. These data can be used to risk-stratify patients. High HbA1c is not a risk factor for genital infections with SGLT2i

    Effect of 18F-fluciclovine positron emission tomography on the management of patients with recurrence of prostate cancer: Results from the FALCON Trial

    Get PDF
    Purpose: Early and accurate localization of lesions in patients with biochemical recurrence (BCR) of prostate cancer may guide salvage therapy decisions. The present study, 18F-Fluciclovine PET/CT in biochemicAL reCurrence Of Prostate caNcer (FALCON; NCT02578940), aimed to evaluate the effect of 18F-fluciclovine on management of men with BCR of prostate cancer. Methods and Materials: Men with a first episode of BCR after curative-intent primary therapy were enrolled at 6 UK sites. Patients underwent 18F-fluciclovine positron emission tomography/computed tomography (PET/CT) according to standardized procedures. Clinicians documented management plans before and after scanning, recording changes to treatment modality as major and changes within a modality as other. The primary outcome measure was record of a revised management plan postscan. Secondary endpoints were evaluation of optimal prostate specific antigen (PSA) threshold for detection, salvage treatment outcome assessment based on 18F-fluciclovine-involvement, and safety. Results: 18F-Fluciclovine was well tolerated in the 104 scanned patients (median PSA = 0.79 ng/mL). Lesions were detected in 58 out of 104 (56%) patients. Detection was broadly proportional to PSA level; ≤1 ng/mL, 1 out of 3 of scans were positive, and 93% scans were positive at PSA >2.0 ng/mL. Sixty-six (64%) patients had a postscan management change (80% after a positive result). Major changes (43 out of 66; 65%) were salvage or systemic therapy to watchful waiting (16 out of 66; 24%); salvage therapy to systemic therapy (16 out of 66; 24%); and alternative changes to treatment modality (11 out of 66, 17%). The remaining 23 out of 66 (35%) management changes were modifications of the prescan plan: most (22 out of 66; 33%) were adjustments to planned brachytherapy/radiation therapy to include a 18F-fluciclovine-guided boost. Where 18F-fluciclovine guided salvage therapy, the PSA response rate was higher than when 18F-fluciclovine was not involved (15 out of 17 [88%] vs 28 out of 39 [72%]). Conclusions: 18F-Fluciclovine PET/CT located recurrence in the majority of men with BCR, frequently resulting in major management plan changes. Incorporating 18F-fluciclovine PET/CT into treatment planning may optimize targeting of recurrence sites and avoid futile salvage therapy

    The Seventh Data Release of the Sloan Digital Sky Survey

    Get PDF
    This paper describes the Seventh Data Release of the Sloan Digital Sky Survey (SDSS), marking the completion of the original goals of the SDSS and the end of the phase known as SDSS-II. It includes 11663 deg^2 of imaging data, with most of the roughly 2000 deg^2 increment over the previous data release lying in regions of low Galactic latitude. The catalog contains five-band photometry for 357 million distinct objects. The survey also includes repeat photometry over 250 deg^2 along the Celestial Equator in the Southern Galactic Cap. A coaddition of these data goes roughly two magnitudes fainter than the main survey. The spectroscopy is now complete over a contiguous area of 7500 deg^2 in the Northern Galactic Cap, closing the gap that was present in previous data releases. There are over 1.6 million spectra in total, including 930,000 galaxies, 120,000 quasars, and 460,000 stars. The data release includes improved stellar photometry at low Galactic latitude. The astrometry has all been recalibrated with the second version of the USNO CCD Astrograph Catalog (UCAC-2), reducing the rms statistical errors at the bright end to 45 milli-arcseconds per coordinate. A systematic error in bright galaxy photometr is less severe than previously reported for the majority of galaxies. Finally, we describe a series of improvements to the spectroscopic reductions, including better flat-fielding and improved wavelength calibration at the blue end, better processing of objects with extremely strong narrow emission lines, and an improved determination of stellar metallicities. (Abridged)Comment: 20 pages, 10 embedded figures. Accepted to ApJS after minor correction

    Intelligence, reason of state and the art of governing risk and opportunity in early modern Europe

    Get PDF
    Drawing upon primary and secondary historical material, this paper explores the role of intelligence in early modern government. It focuses upon developments in seventeenth- and early-eighteenth-century England, a site-specific genealogical moment in the broader history of state power/knowledges. Addressing a tendency in Foucauldian work to neglect pre-eighteenth-century governance, the analysis reveals a set of interrelated processes which gave rise to an innovative technique for anticipating hazard and opportunity for the state. At the intersection of raison d’État, the evolving art of government, widespread routines of secrecy and a post-Westphalia field of European competition and exchange, intelligence was imagined as a fundamental solution to the concurrent problems of ensuring peace and stability while improving state forces. In the administrative offices of the English Secretary of State, an assemblage of complex and interrelated procedures sought to produce and manipulate information in ways which exposed both possible risks to the state and potential opportunities for expansion and gain. As this suggests, the art of intelligence played an important if largely unacknowledged role in the formation and growth of the early modern state. Ensuring strategic advantage over rivals, intelligence also limited the ability of England's neighbours to dominate trade, control the seas and master the colonies, functioning as a constitutive feature of European balance and equilibrium. As the analysis concludes, understanding intelligence as a form of governmental technique – a way of doing something – reveals an entirely novel way of thinking about and investigating its myriad (historical and contemporary) formations

    Establishing a large prospective clinical cohort in people with head and neck cancer as a biomedical resource: head and neck 5000

    Get PDF
    BACKGROUND: Head and neck cancer is an important cause of ill health. Survival appears to be improving but the reasons for this are unclear. They could include evolving aetiology, modifications in care, improvements in treatment or changes in lifestyle behaviour. Observational studies are required to explore survival trends and identify outcome predictors. METHODS: We are identifying people with a new diagnosis of head and neck cancer. We obtain consent that includes agreement to collect longitudinal data, store samples and record linkage. Prior to treatment we give participants three questionnaires on health and lifestyle, quality of life and sexual history. We collect blood and saliva samples, complete a clinical data capture form and request a formalin fixed tissue sample. At four and twelve months we complete further data capture forms and send participants further quality of life questionnaires. DISCUSSION: This large clinical cohort of people with head and neck cancer brings together clinical data, patient-reported outcomes and biological samples in a single co-ordinated resource for translational and prognostic research
    corecore