2,306 research outputs found

    Imaging Subtle Microstructural Variations in Ceramics with Precision Ultrasonic Velocity and Attenuation Measurements

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    There is an international research effort to incorporate ceramic components into hot sections of heat engines. A major portion of this effort is directed towards the understanding and control of ceramic processing so that the strength of ceramics may be optimized. To date, the strength of sintered ceramics (e.g., SiC) is well below, by about two orders of magnitude, the theoretical strength [1,4]. This discrepancy is understood to be due to the presence of voids, inclusions, agglomerates, and anomalously large grains [4]. These defects, causing premature failure, are introduced or formed during the ceramic manufacturing process. Considerable work has already been done to remove these strength reducing material variations. This has resulted in a steady increase in the fracture strength of ceramics; however, the rate of this increase has slowed. Adding to the problem is the fact that the fracture strength of identically produced experimental samples varies as much as 35 percent [2]. As a result of the loss of momentum toward higher strengths, researchers are turning to ceramic- ceramic fiber composites. These composites show promise of increasing the fracture strength of ceramic materials even further. It is likely that the same material strength variations will be present, at least locally in the matrix, in ceramic composites

    WATCCH: a multiprofessional approach to widening participation in healthcare careers.

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    Background Students from lower socioeconomic backgrounds are underrepresented in higher education and healthcare careers. Whilst most healthcare-related widening participation schemes focus on one healthcare profession, the Widening Access to Careers in Community Healthcare (WATCCH) programme at Imperial College London supports participation in a range of community healthcare careers. We aim to evaluate the impact of WATCCH on students’ perceptions and aspirations towards community healthcare careers. Method WATCCH provides educational and application support to 16–18 year-old students interested in a variety of community healthcare careers via work experience, educational workshops and mentoring. The programme was evaluated by focus groups using semi-structured questions to explore the impact of WATCCH on students’ healthcare career perceptions and aspirations. Results Five themes were identified from the focus groups: increased awareness and understanding of a range of community healthcare careers; improved insight into the realities of healthcare careers enabling reflection on career aspirations; altered perceptions of healthcare professionals and acquisition of new role models; increased confidence in achieving a career in healthcare; and valued access to previously inaccessible work experience. Discussion WATCCH is a multi-professional widening participation programme that has supported students from lower socioeconomic backgrounds interested in entering healthcare careers by increasing insights into varied healthcare careers, provision of role models, and increasing students’ confidence of ability to enter healthcare careers. Similar programmes in other institutions could support large numbers of aspiring students to enter varied community healthcare careers in the future

    LES-based Study of the Roughness Effects on the Wake of a Circular Cylinder from Subcritical to Transcritical Reynolds Numbers

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    This paper investigates the effects of surface roughness on the flow past a circular cylinder at subcritical to transcritical Reynolds numbers. Large eddy simulations of the flow for sand grain roughness of size k/D = 0.02 are performed (D is the cylinder diameter). Results show that surface roughness triggers the transition to turbulence in the boundary layer at all Reynolds numbers, thus leading to an early separation caused by the increased momentum deficit, especially at transcritical Reynolds numbers. Even at subcritical Reynolds numbers, boundary layer instabilities are triggered in the roughness sublayer and eventually lead to the transition to turbulence. The early separation at transcritical Reynolds numbers leads to a wake topology similar to that of the subcritical regime, resulting in an increased drag coefficient and lower Strouhal number. Turbulent statistics in the wake are also affected by roughness; the Reynolds stresses are larger due to the increased turbulent kinetic energy production in the boundary layer and separated shear layers close to the cylinder shoulders.We acknowledge “Red Española de Surpercomputación” (RES) for awarding us access to the MareNostrum III machine based in Barcelona, Spain (Ref. FI-2015-2-0026 and FI-2015-3-0011). We also acknowledge PRACE for awarding us access to Fermi and Marconi Supercomputers at Cineca, Italy (Ref. 2015133120). Oriol Lehmkuhl acknowledges a PDJ 2014 Grant by AGAUR (Generalitat de Catalunya). Ugo Piomelli acknowledges the support of the Natural Sciences and Engineering Research Council (NSERC) of Canada under the Discovery Grant Programme (Grant No. RGPIN-2016-04391). Ricard Borrell acknowledges a Juan de la Cierva postdoctoral grant (IJCI-2014-21034). Ivette Rodriguez, Oriol Lehmkuhl, Ricard Borrell and Assensi Oliva acknowledge Ministerio de Economía y Competitividad, Secretaría de Estado de Investigación, Desarrollo e Innovación, Spain (ref. ENE2014-60577-R).Peer ReviewedPostprint (author's final draft

    Caspase-3 and caspase-8 expression in breast cancer: caspase-3 is associated with survival

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    Impaired apoptosis is one of the hallmarks of cancer. Caspase-3 and -8 are key regulators of the apoptotic response and have been shown to interact with the calpain family, a group of cysteine proteases, during tumorigenesis. The current study sought to investigate the prognostic potential of caspase-3 and -8 in breast cancer, as well as the prognostic value of combinatorial caspase and calpain expression. A large cohort (n = 1902) of early stage invasive breast cancer patients was used to explore the expression of caspase-3 and -8. Protein expression was examined using standard immunohistochemistry on tissue microarrays. High caspase-3 expression, but not caspase-8, is significantly associated with adverse breast cancer-specific survival (P = 0.008 and P = 0.056, respectively). Multivariate analysis showed that caspase-3 remained an independent factor when confounding factors were included (hazard ratio (HR) 1.347, 95% confidence interval (CI) 1.086–1.670; P = 0.007). The analyses in individual subgroups demonstrated the significance of caspase-3 expression in clinical outcomes in receptor positive (ER, PR or HER2) subgroups (P = 0.001) and in non-basal like subgroup (P = 0.029). Calpain expression had been previously assessed. Significant association was also found between high caspase-3/high calpain-1 and breast cancer-specific survival in the total patient cohort (P = 0.005) and basal-like subgroup (P = 0.034), as indicated by Kaplan–Meier analysis. Caspase-3 expression is associated with adverse breast cancer-specific survival in breast cancer patients, and provides additional prognostic values in distinct phenotypes. Combinatorial caspase and calpain expression can predict worse prognosis, especially in basal-like phenotypes. The findings warrant further validation studies in independent multi-centre patient cohorts

    Neuroprotection in a Novel Mouse Model of Multiple Sclerosis

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    The authors acknowledge the support of the Barts and the London Charity, the Multiple Sclerosis Society of Great Britain and Northern Ireland, the National Multiple Sclerosis Society, USA, notably the National Centre for the Replacement, Refinement & Reduction of Animals in Research, and the Wellcome Trust (grant no. 092539 to ZA). The siRNA was provided by Quark Pharmaceuticals. The funders and Quark Pharmaceuticals had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Identifying sources, pathways and risk drivers in ecosystems of Japanese Encephalitis in an epidemic-prone north Indian district

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    Japanese Encephalitis (JE) has caused repeated outbreaks in endemic pockets of India. This study was conducted in Kushinagar, a highly endemic district, to understand the human-animal-ecosystem interactions, and the drivers that influence disease transmission. Utilizing the ecosystems approach, a cross-sectional, descriptive study, employing mixed methods design was employed. Four villages (two with pig-rearing and two without) were randomly selected from a high, a medium and a low burden (based on case counts) block of Kushinagar. Children, pigs and vectors were sampled from these villages. A qualitative arm was incorporated to explain the findings from the quantitative surveys. All human serum samples were screened for JE-specific IgM using MAC ELISA and negative samples for JE RNA by rRT-PCR in peripheral blood mononuclear cells. In pigs, IgG ELISA and rRT-PCR for viral RNA were used. Of the 242 children tested, 24 tested positive by either rRT-PCR or MAC ELISA; in pigs, 38 out of the 51 pigs were positive. Of the known vectors, Culex vishnui was most commonly isolated across all biotopes. Analysis of 15 blood meals revealed human blood in 10 samples. Univariable analysis showed that gender, religion, lack of indoor residual spraying of insecticides in the past year, indoor vector density (all species), and not being vaccinated against JE in children were significantly associated with JE positivity. In multivariate analysis, only male gender remained as a significant risk factor. Based on previous estimates of symptomatic: asymptomatic cases of JE, we estimate that there should have been 618 cases from Kushinagar, although only 139 were reported. Vaccination of children and vector control measures emerged as major control activities; they had very poor coverage in the studied villages. In addition, lack of awareness about the cause of JE, lack of faith in the conventional medical healthcare system and multiple referral levels causing delay in diagnosis and treatment emerged as factors likely to result in adverse clinical outcomes

    Lenvatinib with etoposide plus ifosfamide in patients with refractory or relapsed osteosarcoma (ITCC-050): a multicentre, open-label, multicohort, phase 1/2 study

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    Background: Tyrosine kinase inhibitors have shown activity in osteosarcoma and might enhance the efficacy of chemotherapy. We aimed to determine the recommended phase 2 dose and antitumour activity of lenvatinib with etoposide plus ifosfamide in patients with refractory or relapsed osteosarcoma. // Methods: This multicentre, open-label, multicohort, phase 1/2 trial was done at 17 hospitals in six countries. Eligible patients were aged 2–25 years, had relapsed or refractory osteosarcoma, measurable or evaluable disease per Response Evaluation Criteria in Solid Tumors version 1.1, Lansky play–performance score or Karnofsky performance score of 50% or higher, up to one previous VEGF or VEGF receptor-targeted therapy, and a life expectancy of at least 3 months. This study includes a combination dose-finding phase 1 part (cohort 3A) and a phase 2 combination expansion in patients with osteosarcoma (cohort 3B). Lenvatinib was administered orally at a starting dose of 11 mg/m2 per day, capped at 24 mg per day, and etoposide (100 mg/m2 per day) plus ifosfamide (3000 mg/m2 per day) were administered intravenously on days 1–3 of each 21-day cycle for a maximum of five cycles. Lenvatinib monotherapy continued after these five cycles until disease progression, toxic effects, or patient choice to discontinue. The phase 1 primary endpoint was to determine the recommended phase 2 dose by evaluating dose-limiting toxicity and the phase 2 primary endpoint was progression-free survival at 4 months. Progression-free survival was measured in the full analysis set, which included all patients enrolled for efficacy outcomes; safety was assessed in all patients who received any study drug. This study is registered with ClinicalTrials.gov, NCT02432274. // Findings: 30 patients were screened for enrolment into cohort 3A between May 9, 2016, and June 3, 2019, and 22 patients for enrolment into cohort 3B between Sept 13, 2018, and July 18, 2019. Eight patients from cohort 3A and two from cohort 3B were ineligible for enrolment in the study. In phase 1, dose-limiting toxicities were observed in three patients (one in the lenvatinib 11 mg/m2 combination group and two in the 14 mg/m2 combination group) and the recommended phase 2 dose was determined as lenvatinib 14 mg/m2 per day (with daily dose cap of 24 mg) and etoposide 100 mg/m2 per day plus ifosfamide 3000 mg/m2 per day administered intravenously on days 1–3 of each 21-day cycle for a maximum of five cycles. 35 patients from phase 1 (cohort 3A; n=15) and phase 2 (cohort 3B; n=20) were treated at the recommended phase 2 dose and their results were pooled. Progression-free survival at 4 months was 51% (95% CI 34–69) in 18 of 35 patients per the binomial estimate. The most common grade 3–4 treatment-emergent adverse events were neutropenia (27 [77%] of 35), thrombocytopenia (25 [71%]), anaemia (19 [54%]), and decreased white blood cell count (19 [54%]). 26 [74%] of 35 patients had serious treatment-emergent adverse events and no treatment-related deaths occurred. // Interpretation: Lenvatinib with etoposide plus ifosfamide shows promising antitumour activity with no new safety signals in patients with refractory and relapsed osteosarcoma. These findings warrant further investigation in an ongoing randomised phase 2 study (NCT04154189)

    Strong coupling, discrete symmetry and flavour

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    We show how two principles - strong coupling and discrete symmetry - can work together to generate the flavour structure of the Standard Model. We propose that in the UV the full theory has a discrete flavour symmetry, typically only associated with tribimaximal mixing in the neutrino sector. Hierarchies in the particle masses and mixing matrices then emerge from multiple strongly coupled sectors that break this symmetry. This allows for a realistic flavour structure, even in models built around an underlying grand unified theory. We use two different techniques to understand the strongly coupled physics: confinement in N=1 supersymmetry and the AdS/CFT correspondence. Both approaches yield equivalent results and can be represented in a clear, graphical way where the flavour symmetry is realised geometrically.Comment: 31 pages, 5 figures, updated references and figure

    Phase I/II study of single-agent lenvatinib in children and adolescents with refractory or relapsed solid malignancies and young adults with osteosarcoma (ITCC-050)

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    Background: We report results from the phase I dose-finding and phase II expansion part of a multicenter, open-label study of single-agent lenvatinib in pediatric and young adult patients with relapsed/refractory solid tumors, including osteosarcoma and radioiodine-refractory differentiated thyroid cancer (RR-DTC) (NCT02432274). // Patients and methods: The primary endpoint of phase I was to determine the recommended phase II dose (RP2D) of lenvatinib in children with relapsed/refractory solid malignant tumors. Phase II primary endpoints were progression-free survival rate at 4 months (PFS-4) for patients with relapsed/refractory osteosarcoma; and objective response rate/best overall response for patients with RR-DTC at the RP2D. // Results: In phase I, 23 patients (median age, 12 years) were enrolled. With lenvatinib 14 mg/m2, three dose-limiting toxicities (hypertension, n = 2; increased alanine aminotransferase, n = 1) were reported, establishing 14 mg/m2 as the RP2D. In phase II, 31 patients with osteosarcoma (median age, 15 years) and 1 patient with RR-DTC (age 17 years) were enrolled. For the osteosarcoma cohort, PFS-4 (binomial estimate) was 29.0% [95% confidence interval (CI) 14.2% to 48.0%; full analysis set: n = 31], PFS-4 by Kaplan–Meier estimate was 37.8% (95% CI 20.0% to 55.4%; full analysis set) and median PFS was 3.0 months (95% CI 1.8-5.4 months). The objective response rate was 6.7% (95% CI 0.8% to 22.1%). The patient with RR-DTC had a best overall response of partial response. Some 60.8% of patients in phase I and 22.6% of patients in phase II (with osteosarcoma) had treatment-related treatment-emergent adverse events of grade ≥3. // Conclusions: The lenvatinib RP2D was 14 mg/m2. Single-agent lenvatinib showed activity in osteosarcoma; however, the null hypothesis could not be rejected. The safety profile was consistent with previous tyrosine kinase inhibitor studies. Lenvatinib is currently being investigated in osteosarcoma in combination with chemotherapy as part of a randomized, controlled trial (NCT04154189), in pediatric solid tumors in combination with everolimus (NCT03245151), and as a single agent in a basket study with enrollment ongoing (NCT04447755)
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