Compact rotation invariant descriptor for non-local means

Non-local means is a recently proposed denoising technique that better preserves image structures than other methods. However, the computational cost of non-local means is prohibitive, especially for large 3D images. Modifications have previously been proposed to reduce the cost, which result in image artefacts. This paper proposes a compact rotation invariant descriptor. Testing demonstrates improved denoising performance relative to optimized non-local means. Rotation invariant non-local means is an order of magnitude faster

Automated, quantitative measures of grey and white matter lesion burden correlates with motor and cognitive function in children with unilateral cerebral palsy

AbstractWhite and grey matter lesions are the most prevalent type of injury observable in the Magnetic Resonance Images (MRIs) of children with cerebral palsy (CP). Previous studies investigating the impact of lesions in children with CP have been qualitative, limited by the lack of automated segmentation approaches in this setting. As a result, the quantitative relationship between lesion burden has yet to be established. In this study, we perform automatic lesion segmentation on a large cohort of data (107 children with unilateral CP and 18 healthy children) with a new, validated method for segmenting both white matter (WM) and grey matter (GM) lesions. The method has better accuracy (94%) than the best current methods (73%), and only requires standard structural MRI sequences. Anatomical lesion burdens most predictive of clinical scores of motor, cognitive, visual and communicative function were identified using the Least Absolute Shrinkage and Selection operator (LASSO). The improved segmentations enabled identification of significant correlations between regional lesion burden and clinical performance, which conform to known structure-function relationships. Model performance was validated in an independent test set, with significant correlations observed for both WM and GM regional lesion burden with motor function (p<0.008), and between WM and GM lesions alone with cognitive and visual function respectively (p<0.008). The significant correlation of GM lesions with functional outcome highlights the serious implications GM lesions, in addition to WM lesions, have for prognosis, and the utility of structural MRI alone for quantifying lesion burden and planning therapy interventions

Increasing feasibility and utility of 18F-FDOPA PET for the management of glioma

Introduction: Despite radical treatment therapies, glioma continues to carry with it a uniformly poor prognosis. Patients diagnosed with WHO Grade IV glioma (glioblastomas; GBM) generally succumb within two years, even those with WHO Grade III anaplastic gliomas and WHO Grade II gliomas carry prognoses of 2-5 and 2 years, respectively. PET imaging with F-18-FDOPA allows in vivo assessment of the metabolism of glioma relative to surrounding tissues. The high sensitivity of F-18-DOPA imaging grants utility for a number of clinical applications

Sansanmycin natural product analogues as potent and selective anti-mycobacterials that inhibit lipid I biosynthesis.

Tuberculosis (TB) is responsible for enormous global morbidity and mortality, and current treatment regimens rely on the use of drugs that have been in use for more than 40 years. Owing to widespread resistance to these therapies, new drugs are desperately needed to control the TB disease burden. Herein, we describe the rapid synthesis of analogues of the sansanmycin uridylpeptide natural products that represent promising new TB drug leads. The compounds exhibit potent and selective inhibition of Mycobacterium tuberculosis, the etiological agent of TB, both in vitro and intracellularly. The natural product analogues were also shown to be nanomolar inhibitors of Mtb phospho-MurNAc-pentapeptide translocase, the enzyme responsible for the synthesis of lipid I in mycobacteria. This work lays the foundation for the development of uridylpeptide natural product analogues as new TB drug candidates that operate through the inhibition of peptidoglycan biosynthesis

The Derivation of Bearing Characteristics by Means of Transient Excitation Applied Directly to a Rotating Shaft

graph are the square roots of the appropriate diagonal elements from the error covariance matrix P. These elements provide a first-order approximation to the estimated variance in the states and hence ± Vi^, is an approximate measure of the standard deviation of state estimate x ,•. Increasing the running speed (and hence the excitation frequency) has little effect upon the accuracy of estimation, as shown by the results in A key assumption in producing the above results is that the values of (e/c) and &lt;p are known exactly. Where the unbalance is introduced artificially this is a reasonable assumption, however where natural unbalance is exploited its effective magnitude and angular position would be harder to assess. Consequently a further set of tests was performed involving deliberately-induced errors in the assumed values of (e/c) and Typical results (for a running speed of 3000 rev/min) are shown in Discussion This note has discussed an approach to the identification of linearized journal bearing dynamics under normal operating conditions. Given that an effective technique is already available for estimating the four oil-film stiffness terms, a method must now be developed for extracting reliable estimates of the four damping terms, preferably without the need to conduct further experiments. We have suggested that this can be achieved by reformulating the problem so that an existing algorithm can be applied to estimate the damping terms from noisy measurements of the displacement responses to synchronous excitation. These responses are acquired automatically in any identification experiment and hence the approach could be applied retrospectively to refine estimates of the damping terms. The feasibility of the approach has been tested under controlled conditions by generating data from a linearized model of a simple rotor-bearing system and demonstrating that the governing equations can be reconstructed. In practice the effectiveness of such an approach will depend upon the robustness of the algorithm when processing actual operating data and the accuracy with which the unbalance parameters can be assessed. The effects of modeling errors (introduced by the linearization process) and other disturbances not considered in this note (for example, surface roughness of the shaft and bearings) will obviously be reflected in the eventual results. It is hoped that the results presented here will encourage experimental work to quantify such effects. 2 Holmes, R., &quot;The Vibration of a Rigid Shaft on Short Journal Bearings,&quot; J. Mech. Eng. Set., Vol. 2, 1960, pp. 337-341. 3 Allaire, P. E., Nicholas, J. C, and Gunter, E. J., &quot;Finite-Element Analysis of Fluid-Film Bearings,&quot; University of Virginia Report ME-543-120-75, Charlottesville, Va. 4 Stanway, R., Burrows, C. R., and Holmes, R., &quot;Discrete-Time Modelling of a Squeeze-Film Bearing,&quot; J. Mech. Eng. Sci., Vol. 21, 1979, pp. 419-427. 5 Morton, P. G., &quot;The Derivation of Bearing Characteristics by Means of Transient Excitation Applied Directly to a Rotating Shaft,&quot; G. E. C. Journal of Science and Technology, Vol. 42, 1975, pp. 37-47. 6 Burrows, C. R., and Stanway, R., &quot;Identification of Journal Bearing Characteristics,&quot; ASME JOURNAL OF DYNAMIC SYSTEMS, MEASUREMENT AND CONTROL, Vol. 99, 1977, pp. 167-173. 7 Detchmendy, D. M., and Sridhar, R., &quot;Sequential Estimation of States and Parameters in Noisy Non-Linear Dynamical Systems,&quot; ASME Journal of Basic Engineering, Vol. 88, 1966, pp. 362-368. 8 Woodcock, J. S., and Holmes, R., &quot;The Determination and Application of the Dynamic Properties of a Turbo-Rotor Bearing Oil-Film,&quot; Proc. I. Mech. £., Vol. 184, 1969Vol. 184, -1970. Control of Systems Subject to Introduction Although the study of linear systems receives disproportionate attention in the literature, the fact remains that nonlinear equations are necessary to adequately describe many important control processes. Linear feedback theory may still find an application even in this instance. If the nonlinear system operates near a known nominal condition, a nominal state trajectory and a nominal actuating signal can be determined. Under appropriate conditions, the deviations from the nominal path can be described by a linear model. Linear synthesis algorithms can then be applied to this perturbation model, and a regulator which causes the system to track its nominal trajectory can be deduced thereby. To be more specific about these ideas, consider the problem of synthesizing a feedwater flow rate regulator for control of a solar receiver. Certain aspects of this problem were addressed in [1] an

A High-Resolution View of Genome-Wide Pneumococcal Transformation

Transformation is an important mechanism of microbial evolution through which bacteria have been observed to rapidly adapt in response to clinical interventions; examples include facilitating vaccine evasion and the development of penicillin resistance in the major respiratory pathogen Streptococcus pneumoniae. To characterise the process in detail, the genomes of 124 S. pneumoniae isolates produced through in vitro transformation were sequenced and recombination events detected. Those recombinations importing the selected marker were independent of unselected events elsewhere in the genome, the positions of which were not significantly affected by local sequence similarity between donor and recipient or mismatch repair processes. However, both types of recombinations were sometimes mosaic, with multiple non-contiguous segments originating from the same molecule of donor DNA. The lengths of the unselected events were exponentially distributed with a mean of 2.3 kb, implying that recombinations are stochastically resolved with a fixed per base probability of 4.4×10−4 bp−1. This distribution of recombination sizes, coupled with an observed under representation of large insertions within transferred sequence, suggests transformation has the potential to reduce the size of bacterial genomes, and is unlikely to act as an efficient mechanism for the uptake of accessory genomic loci

Outcomes of obstructed abdominal wall hernia: results from the UK national small bowel obstruction audit

Background: Abdominal wall hernia is a common surgical condition. Patients may present in an emergency with bowel obstruction, incarceration or strangulation. Small bowel obstruction (SBO) is a serious surgical condition associated with significant morbidity. The aim of this study was to describe current management and outcomes of patients with obstructed hernia in the UK as identified in the National Audit of Small Bowel Obstruction (NASBO). Methods: NASBO collated data on adults treated for SBO at 131 UK hospitals between January and March 2017. Those with obstruction due to abdominal wall hernia were included in this study. Demographics, co-morbidity, imaging, operative treatment, and in-hospital outcomes were recorded. Modelling for factors associated with mortality and complications was undertaken using Cox proportional hazards and multivariable regression modelling. Results: NASBO included 2341 patients, of whom 415 (17·7 per cent) had SBO due to hernia. Surgery was performed in 312 (75·2 per cent) of the 415 patients; small bowel resection was required in 198 (63·5 per cent) of these operations. Non-operative management was reported in 35 (54 per cent) of 65 patients with a parastomal hernia and in 34 (32·1 per cent) of 106 patients with an incisional hernia. The in-hospital mortality rate was 9·4 per cent (39 of 415), and was highest in patients with a groin hernia (11·1 per cent, 17 of 153). Complications were common, including lower respiratory tract infection in 16·3 per cent of patients with a groin hernia. Increased age was associated with an increased risk of death (hazard ratio 1·05, 95 per cent c.i. 1·01 to 1·10; P = 0·009) and complications (odds ratio 1·05, 95 per cent c.i. 1·02 to 1·09; P = 0·001). Conclusion: NASBO has highlighted poor outcomes for patients with SBO due to hernia, highlighting the need for quality improvement initiatives in this group

National prospective cohort study of the burden of acute small bowel obstruction

Background Small bowel obstruction is a common surgical emergency, and is associated with high levels of morbidity and mortality across the world. The literature provides little information on the conservatively managed group. The aim of this study was to describe the burden of small bowel obstruction in the UK. Methods This prospective cohort study was conducted in 131 acute hospitals in the UK between January and April 2017, delivered by trainee research collaboratives. Adult patients with a diagnosis of mechanical small bowel obstruction were included. The primary outcome was in‐hospital mortality. Secondary outcomes included complications, unplanned intensive care admission and readmission within 30 days of discharge. Practice measures, including use of radiological investigations, water soluble contrast, operative and nutritional interventions, were collected. Results Of 2341 patients identified, 693 (29·6 per cent) underwent immediate surgery (within 24 h of admission), 500 (21·4 per cent) had delayed surgery after initial conservative management, and 1148 (49·0 per cent) were managed non‐operatively. The mortality rate was 6·6 per cent (6·4 per cent for non‐operative management, 6·8 per cent for immediate surgery, 6·8 per cent for delayed surgery; P = 0·911). The major complication rate was 14·4 per cent overall, affecting 19·0 per cent in the immediate surgery, 23·6 per cent in the delayed surgery and 7·7 per cent in the non‐operative management groups (P < 0·001). Cox regression found hernia or malignant aetiology and malnutrition to be associated with higher rates of death. Malignant aetiology, operative intervention, acute kidney injury and malnutrition were associated with increased risk of major complication. Conclusion Small bowel obstruction represents a significant healthcare burden. Patient‐level factors such as timing of surgery, acute kidney injury and nutritional status are factors that might be modified to improve outcomes