485 research outputs found

    Minimal Position-Velocity Uncertainty Wave Packets in Relativistic and Non-relativistic Quantum Mechanics

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    We consider wave packets of free particles with a general energy-momentum dispersion relation E(p)E(p). The spreading of the wave packet is determined by the velocity v = \p_p E. The position-velocity uncertainty relation ΔxΔv1/2\Delta x \Delta v \geq {1/2} || is saturated by minimal uncertainty wave packets Φ(p)=Aexp(αE(p)+βp)\Phi(p) = A \exp(- \alpha E(p) + \beta p). In addition to the standard minimal Gaussian wave packets corresponding to the non-relativistic dispersion relation E(p)=p2/2mE(p) = p^2/2m, analytic calculations are presented for the spreading of wave packets with minimal position-velocity uncertainty product for the lattice dispersion relation E(p)=cos(pa)/ma2E(p) = - \cos(p a)/m a^2 as well as for the relativistic dispersion relation E(p)=p2+m2E(p) = \sqrt{p^2 + m^2}. The boost properties of moving relativistic wave packets as well as the propagation of wave packets in an expanding Universe are also discussed

    Effect of under-reinforcement on the flexural strength of corroded beams

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    Reinforced concrete beams are normally designed as under-reinforced to provide ductile behaviour i.e. the tensile moment of resistance, Mt(0) is less than the moment of resistance of the compressive zone, Mc. The degree of under-reinforcement (Mt(0)/Mc ratio) can depend upon the preferences of the designer in complying with design and construction constraints, codes and availability of steel reinforcement diameters and length. Mt(0)/Mc is further influenced during service life by corrosion which decreases Mt(0). The paper investigates the influence of Mt(0)/Mc on the residual flexural strength of corroded beams and determines detailing parameters (e.g. size and percentage of steel reinforcement, cover) on Mt(0)/Mc. Corroded reinforced concrete beams (100 mm · 150 mm deep) with varying Mt(0)/Mc ratios were tested in flexure. The results of the investigation were combined with the results of similar work by other researchers and show that beams with lower Mt(0)/Mc ratios suffer lower flexural strength loss when subjected to tensile reinforcement corrosion. Cover to the main steel does not directly influence Mt(0)/Mc and, thus, the residual flexural strength of corroded beams is not normally affected by increased cover. A simplified expression for estimating the residual strength of corroded beams is also given

    A multi-gene signature predicts outcome in patients with pancreatic ductal adenocarcinoma.

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    © 2014 Haider et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Improved usage of the repertoires of pancreatic ductal adenocarcinoma (PDAC) profiles is crucially needed to guide the development of predictive and prognostic tools that could inform the selection of treatment options

    Diagnostic Testing of Pediatric Fevers: Meta-Analysis of 13 National Surveys Assessing Influences of Malaria Endemicity and Source of Care on Test Uptake for Febrile Children under Five Years.

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    In 2010, the World Health Organization revised guidelines to recommend diagnosis of all suspected malaria cases prior to treatment. There has been no systematic assessment of malaria test uptake for pediatric fevers at the population level as countries start implementing guidelines. We examined test use for pediatric fevers in relation to malaria endemicity and treatment-seeking behavior in multiple sub-Saharan African countries in initial years of implementation. We compiled data from national population-based surveys reporting fever prevalence, care-seeking and diagnostic use for children under five years in 13 sub-Saharan African countries in 2009-2011/12 (n = 105,791). Mixed-effects logistic regression models quantified the influence of source of care and malaria endemicity on test use after adjusting for socioeconomic covariates. Results were stratified by malaria endemicity categories: low (PfPR2-10<5%), moderate (PfPR2-10 5-40%), high (PfPR2-10>40%). Among febrile under-fives surveyed, 16.9% (95% CI: 11.8%-21.9%) were tested. Compared to hospitals, febrile children attending non-hospital sources (OR: 0.62, 95% CI: 0.56-0.69) and community health workers (OR: 0.31, 95% CI: 0.23-0.43) were less often tested. Febrile children in high-risk areas had reduced odds of testing compared to low-risk settings (OR: 0.51, 95% CI: 0.42-0.62). Febrile children in least poor households were more often tested than in poorest (OR: 1.63, 95% CI: 1.39-1.91), as were children with better-educated mothers compared to least educated (OR: 1.33, 95% CI: 1.16-1.54). Diagnostic testing of pediatric fevers was low and inequitable at the outset of new guidelines. Greater testing is needed at lower or less formal sources where pediatric fevers are commonly managed, particularly to reach the poorest. Lower test uptake in high-risk settings merits further investigation given potential implications for diagnostic scale-up in these areas. Findings could inform continued implementation of new guidelines to improve access to and equity in point-of-care diagnostics use for pediatric fevers

    Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

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    Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

    Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

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    Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

    Validation of childhood lupus specific targets: Ensuring accurate assessment of disease control in younger, lighter paediatric patients

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    \ua9 2025 The Author(s).Objectives: To validate novel childhood-onset systemic lupus erythematosus (cSLE) treat-To-Target targets including childhood lupus low disease activity state (cLLDAS), cSLE clinical remission on steroids (cCR) and cSLE clinical remission off steroids (cCR-0), as compared with adult-onset SLE (aSLE) targets. Methods: Attainment of the aforementioned cSLE-specific and aSLE-specific targets (LLDAS, DORIS 2021 Remission) was assessed at each visit in UK JSLE Cohort Study patients. Univariable and multivariable Prentice-Williams-Peterson (PWP) gap-Time models investigated the impact of target attainment on new damage and severe flare. Results: The cohort included 430 cSLE patients. Attainability was comparable between corresponding cSLE and aSLE targets. Achieving cLLDAS (hazard ratio [HR] 0.18 [95% CI: 0.14, 0.23]), cCR (HR 0.18 [0.13, 0.23]) and cCR-0 (HR 0.17 [0.13, 0.23]) reduced the risk of severe flare (all P &lt; 0.001). Risk of new damage was reduced in those reaching cLLDAS (HR 0.22 [0.11, 0.44]), cCR (HR 0.25 [0.13, 0.49]) and cCR-0 (HR 0.30 [0.15, 0.60]) (all P &lt; 0.001). Inappropriate attainment of LLDAS and DORIS remission occurred at 35 and 52 visits, respectively, in younger (median age 7.3 and 8.8 years, respectively) and lighter (median weight 26.8 and 37.1 kg, respectively) patients whilst on prednisolone doses that precluded cSLE target attainment (median 0.17 [IQR 0.16-0.24] and 0.13 [IQR 0.11-0.16] mg/kg/day, respectively). Conclusions: This study validates novel paediatric-specific targets, demonstrating that achieving cLLDAS, cCR and cCR-0 reduces risks of new damage and severe flare, which is comparable to aSLE targets. Using cSLE-specific targets prevents misclassification of disease activity in paediatric patients, enabling more accurate disease control assessments in younger, lighter patients
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