Concentration of the distance between points in the unit ball

We prove that in every finite dimensional normed space, for “most” pairs (x, y) of points in the unit ball, ║x − y║ is more than √2(1 − ε). As a consequence, we obtain a result proved by Bourgain, using QS-decomposition, that guarantees an exponentially large number of points in the unit ball any two of which are separated by more than √2(1 − ε)

Exploring the potential relationships between microvascular haemodynamics and density in bone: a feasibility study utilising near infrared spectroscopy

This is the author accepted manuscript. The final version is available from UKIO2019 via the link in this recordRoyal College of Radiologist

Space Efficient Breadth-First and Level Traversals of Consistent Global States of Parallel Programs

Enumerating consistent global states of a computation is a fundamental problem in parallel computing with applications to debug- ging, testing and runtime verification of parallel programs. Breadth-first search (BFS) enumeration is especially useful for these applications as it finds an erroneous consistent global state with the least number of events possible. The total number of executed events in a global state is called its rank. BFS also allows enumeration of all global states of a given rank or within a range of ranks. If a computation on n processes has m events per process on average, then the traditional BFS (Cooper-Marzullo and its variants) requires $\mathcal{O}(\frac{m^{n-1}}{n})$ space in the worst case, whereas ou r algorithm performs the BFS requires $\mathcal{O}(m^2n^2)$ space. Thus, we reduce the space complexity for BFS enumeration of consistent global states exponentially. and give the first polynomial space algorithm for this task. In our experimental evaluation of seven benchmarks, traditional BFS fails in many cases by exhausting the 2 GB heap space allowed to the JVM. In contrast, our implementation uses less than 60 MB memory and is also faster in many cases

Understanding student radiographer attrition: Risk factors and strategies

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordIntroduction Diagnostic student radiographer attrition is reported at 14%, 6% higher than the average for higher education, however, little research has been undertaken on this subject. This study explored risk factors for attrition and strategies that enabled these to be overcome. Methods A two-phase study was undertaken. Phase one: data for 579 former student diagnostic radiographers (468 completers and 111 non-completers) from 3 English universities were analysed. Logistic regression was used to estimate odds ratios and 95% confidence intervals for completion based on individual characteristics. Phase two: content analysis of data from an online survey of 186 current UK student diagnostic radiographers exploring their experiences was undertaken. Results Phase one: Attrition was 19%. Increased age, non A-level entry qualifications and poor academic performance were predictors of attrition (p < 0.005). Phase two: Challenges reported by groups identified as ‘at risk’ showed that for mature students and those with non-traditional entry qualifications, external responsibilities/pressures and financial pressures were likely to be the greatest cause of attrition and for younger students with traditional qualifications, academic difficulty and excessive workload were most significant. Scientific learning and academic writing were identified as the most common academic difficulties by all groups. Poor mental health may also be a risk factor. Conclusion Although characteristics were identified that increased the chance of attrition, the study concluded that attrition is most likely to be multi-factorial. Academic and personal support were identified as key in students continuing their studies when they considered leaving. Clinical placement experience is likely to influence continuation decisions. Implications for practice Transparency around course expectations and academic requirements together with ensuring high quality clinical placements may assist in reducing attrition.University of ExeterNational Institute for Health Research (NIHR

Barriers to lung cancer care: health professionals' perspectives.

PURPOSE: Globally, lung cancer is the most common cancer and the leading cause of cancer death. Problematically, there is a wide variation in the management and survival for people with lung cancer and there is limited understanding of the reasons for these variations. To date, the views of health professionals across relevant disciplines who deliver such care are largely absent. The present study describes Australian health professionals' views about barriers to lung cancer care to help build a research and action agenda for improving lung cancer outcomes. METHODS: Qualitative semi-structured interviews were undertaken with a multidisciplinary group of 31 Australian health professionals working in lung cancer care for an average of 16 years (range 1-35 yrs.; SD = 10.2) seeing a mean of 116 patients annually. RESULTS: Three superordinate themes were identified: illness representations, cultural influences, and health system context. Illness representations included three themes: symptoms attributed as smoking-related but not cancer, health-related stigma, and therapeutic nihilism. Cultural influence themes included Indigenous health care preferences, language and communication, and sociodemographic factors. Health system context included lack of regional services and distance to treatment, poor care coordination, lack of effective screening methods, and health professional behaviours. CONCLUSIONS: Fractured and locally isolated approaches routinely confound responses to the social, cultural and health system complexities that surround a diagnosis of lung cancer and subsequent treatment. Improving outcomes for this disadvantaged patient group will require government, health agencies, and the community to take an aggressive, integrated approach balancing health policy, treatment priorities, and societal values

Capillary pressure may predict preclinical changes in the eye

This is the final version. Available on open access from Springer Verlag via the DOI in this recordAIMS/HYPOTHESIS: Microvascular dysfunction is associated with end-organ damage. Macular oedema is an important component of diabetic retinopathy. Macular thickness can be accurately quantified by optical coherence tomography (OCT), enabling accurate assessment of the macular prior to clinically apparent abnormalities. We investigated whether macular (fovea) thickness in non-diabetic individuals is related to the microvascular variables controlling fluid filtration across a blood vessel wall, in particular capillary pressure and the microvascular filtration capacity (Kf). METHODS: We recruited 50 non-diabetic individuals (25 men, 25 women; age range: 26-78 years; BMI range: 20-46 kg/m(2)). Fovea thickness was assessed by OCT. Microvascular assessments included: finger nailfold capillary pressure; Kf; microvascular structural assessments, i.e. skin vasodilatory capacity, minimum vascular resistance (MVR) and microvascular distensibility; and endothelial function. RESULTS: At 214.6 (19.9) microm (mean [SD]), fovea thickness was within normal range. Capillary pressure, adjusted for BMI, was associated with fovea thickness (standardised beta 0.573, p = 0.006, linear regression). Fovea thickness was not associated with Kf, microvascular structural assessments or endothelial function. Capillary pressure was still associated with fovea thickness when adjusted for microvascular variables (Kf, vasodilatory capacity, MVR, microvascular distensibility or endothelial function), or for risk factors for diabetes (systemic blood pressure, insulin sensitivity, inflammation, glycaemic status and lipids) and age. CONCLUSIONS/INTERPRETATION: Capillary pressure, a key determinant of movement of fluid across a blood vessel wall, is associated with fovea thickness in non-diabetic individuals. This suggests that with regard to potential preventative or therapeutic targets, attention should be directed at the mechanisms determining retinal microvascular pressure.Diabetes UKNational Institute for Health Research (NIHR

Systematic review of patient-specific predictors of pain improvement to endometriosis surgery

BACKGROUND: Up to 28% of endometriosis patients do not get pain relief from therapeutic laparoscopy but this subgroup is not defined. OBJECTIVES: To identify any prognostic patient-specific factors (such as but not limited to patients’ type or location of endometriosis, sociodemographics and lifestyle) associated with a clinically meaningful reduction in post-surgical pain response to operative laparoscopic surgery for endometriosis. SEARCH STRATEGY: PubMed, Cochrane and Embase databases were searched from inception to 19th May 2020 without language restrictions. Backward and forward citation tracking was used. SELECTION CRITERIA, DATA COLLECTION AND ANALYSIS: Cohort studies reporting prognostic factors, along with scores for domains of pain associated with endometriosis before and after surgery, were included. Studies that compared surgeries, or laboratory tests, or outcomes without stratification were excluded. Results were synthesised but variation in study designs and inconsistency of outcome reporting precluded us from doing a meta-analysis. MAIN RESULTS: Five studies were included. Quality assessment using the Newcastle Ottawa Scale graded three studies as high, one as moderate and one as having a low risk of bias. Four of five included studies separately reported that a relationship exists between more severe endometriosis and stronger pain relief from laparoscopic surgery CONCLUSION: Currently there are few studies of appropriate quality to answer the research question. We recommend future studies report core outcome sets to enable meta-analysis. FUNDING: NIHR PB-PG-0317-20018 PROSPERO: CRD4201810860

Post coital aortic dissection: a case report

<p>Abstract</p> <p>Background</p> <p>Sudden onset peri- or post-coital cardiovascular disease is well documented in the literature including myocardial infarction, pulmonary embolus and subarachnoid haemorrhage. The occurrence of aortic dissection in this setting has been reported only once previously.</p> <p>Case presentation</p> <p>We report the case of a 47 year old man who developed sudden onset right leg pain during coitus. This was initially believed to be neurological due to nerve impingement but an MRI failed to identify a prolapse. On further review after 6 weeks, pulses were noted to be absent in the patient's right leg and an urgent vascular review with investigation identified a dissection of the aorta which was subsequently successfully treated.</p> <p>Conclusion</p> <p>This case illustrates a rare presentation of aortic dissection and demonstrates the importance of a thorough vascular assessment in the presence of sudden onset limb pain.</p

In vivo Measurement of Intraosseous Vascular Haemodynamic Markers in Human Bone Tissue Utilising Near Infrared Spectroscopy

This is the final version. Available on open access from Frontiers Media via the DOI in this recordData Availability Statement: The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.Objective: Poor vascular health is associated with reduced bone strength and increased risk of fragility fracture. However, direct measurement of intraosseous vascular health is difficult due to the density and mineral content of bone. We investigated the feasibility of using a commercially available continuous wave near infrared spectroscopy (NIRS) system for the investigation of vascular haemodynamics in human bone in vivo. Approach: An arterial occlusion (AO) protocol was developed for obtaining haemodynamic measurements of the proximal tibia and lateral calf, including assessment of the protocol’s intra operator reproducibility. For 36 participants, intraosseous haemodynamics derived by NIRS were compared to alternative tests of bone health based on dual x-ray absorptiometry (DXA) testing and MRI. Main Results: Near infrared spectroscopy markers of haemodynamics of the proximal tibia demonstrated acceptable reproducibility, comparable with reproducibility assessments of alternative modalities measuring intraosseous haemodynamics, and the use of NIRS for measuring muscle. Novel associations have been demonstrated between haemodynamic markers of bone measured with NIRS and body composition and bone mineral density (BMD) measurements obtained with both DXA and MRI. Significance: Near infrared spectroscopy provides inexpensive, non-invasive, safe, and real time data on changes in oxygenated and deoxygenated haemoglobin concentration in bone at the proximal tibia. This study has demonstrated the potential for NIRS to contribute to research investigating the pathophysiological role of vascular dysfunction within bone tissue, but also the limitations and need for further development of NIRS technology.College of RadiographersNational Institute for Health Research (NIHR

Lewis X antigen mediates adhesion of human breast carcinoma cells to activated endothelium. Possible involvement of the endothelial scavenger receptor C-Type lectin

Lewis x (Lex, CD15), also known as SSEA-1 (stage specific embryonic antigen-1), is a trisaccharide with the structure Galβ(1–4)Fucα(1–3)GlcNAc, which is expressed on glycoconjugates in human polymorphonuclear granulocytes and various tumors such as colon and breast carcinoma. We have investigated the role of Lex in the adhesion of MCF-7 human breast cancer cells and PMN to human umbilical endothelial cells (HUVEC) and the effects of two different anti-Lex mAbs (FC-2.15 and MCS-1) on this adhesion. We also analyzed the cytolysis of Lex+-cells induced by anti-Lex mAbs and complement when cells were adhered to the endothelium, and the effect of these antibodies on HUVEC. The results indicate that MCF-7 cells can bind to HUVEC, and that MCS-1 but not FC-2.15 mAb inhibit this interaction. Both mAbs can efficiently lyse MCF-7 cells bound to HUVEC in the presence of complement without damaging endothelial cells. We also found a Lex-dependent PMN interaction with HUVEC. Although both anti-Lex mAbs lysed PMN in suspension and adhered to HUVEC, PMN aggregation was only induced by mAb FC-2.15. Blotting studies revealed that the endothelial scavenger receptor C-type lectin (SRCL), which binds Lex-trisaccharide, interacts with specific glycoproteins of Mr␣∼␣28 kD and 10 kD from MCF-7 cells. The interaction between Lex+-cancer cells and vascular endothelium is a potential target for cancer treatment.Fil: Elola, Maria Teresa. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Capurro, Mariana Isabel. University of Toronto; CanadáFil: Barrio, Maria Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación, Docencia y Prevención del Cáncer; ArgentinaFil: Coombs, Peter J.. Imperial College London; Reino UnidoFil: Taylor, Maureen E.. Imperial College London; Reino UnidoFil: Drickamer, Kurt. Imperial College London; Reino UnidoFil: Mordoh, Jose. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Investigación, Docencia y Prevención del Cáncer; Argentin