301 research outputs found

    Cancer in the offspring of radiation workers: an investigation of employment timing and a reanalysis using updated dose information

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    An earlier case-control study found no evidence of paternal preconceptional irradiation (PPI) as a cause of childhood leukaemia and non-Hodgkin's lymphoma (LNHL). Although fathers of children with LNHL were more likely to have been radiation workers, the risk was most marked in those with doses below the level of detection. The timing of paternal employment as a radiation worker has now been examined. The previously reported elevated risk of LNHL in the children of male radiation workers was limited to those whose fathers were still radiation workers at conception or whose employment also continued until diagnosis. Children whose fathers stopped radiation work prior to their conception were found to have no excess risk of LNHL. It was not possible to distinguish between the risks associated with paternal radiation work at conception and at the time of diagnosis. A reanalysis of the original study hypothesis incorporating updated dosimetric information gave similar results to those obtained previously. In particular, the risks of LNHL did not show an association with radiation doses received by the father before conception. It seems likely that the increased risk of LNHL among the children of male radiation workers is associated with an increased exposure to some infective agent consequent on high levels of population mixing

    Who pays and who benefits? How different models of shared responsibilities between formal and informal carers influence projections of costs of dementia management

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    <p>Abstract</p> <p>Background</p> <p>The few studies that have attempted to estimate the future cost of caring for people with dementia in Australia are typically based on total prevalence and the cost per patient over the average duration of illness. However, costs associated with dementia care also vary according to the length of the disease, severity of symptoms and type of care provided. This study aimed to determine more accurately the future costs of dementia management by taking these factors into consideration.</p> <p>Methods</p> <p>The current study estimated the prevalence of dementia in Australia (2010-2040). Data from a variety of sources was recalculated to distribute this prevalence according to the location (home/institution), care requirements (informal/formal), and dementia severity. The cost of care was attributed to redistributed prevalences and used in prediction of future costs of dementia.</p> <p>Results</p> <p>Our computer modeling indicates that the ratio between the prevalence of people with mild/moderate/severe dementia will change over the three decades from 2010 to 2040 from 50/30/20 to 44/32/24.</p> <p>Taking into account the severity of symptoms, location of care and cost of care per hour, the current study estimates that the informal cost of care in 2010 is AU3.2billionandformalcareatAU3.2 billion and formal care at AU5.0 billion per annum. By 2040 informal care is estimated to cost AU11.6billionandformalcare11.6 billion and formal care AU16.7 billion per annum. Interventions to slow disease progression will result in relative savings of 5% (AU1.5billion)perannumandinterventionstodelaydiseaseonsetwillresultinrelativesavingsof141.5 billion) per annum and interventions to delay disease onset will result in relative savings of 14% (AU4 billion) of the cost per annum.</p> <p>With no intervention, the projected combined annual cost of formal and informal care for a person with dementia in 2040 will be around AU38,000(in2010dollars).Aninterventiontodelayprogressionby2yearswillseethisreducedtoAU38,000 (in 2010 dollars). An intervention to delay progression by 2 years will see this reduced to AU35,000.</p> <p>Conclusions</p> <p>These findings highlight the need to account for more than total prevalence when estimating the costs of dementia care. While the absolute values of cost of care estimates are subject to the validity and reliability of currently available data, dynamic systems modeling allows for future trends to be estimated.</p

    Distinguishing Various Models of the 125 GeV Boson in Vector Boson Fusion

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    The hint of a new particle around 125 GeV at the LHC through the decay modes of diphoton and a number of others may point to quite a number of possibilities. While at the LHC the dominant production mechanism for the Higgs boson of the standard model and some other extensions is via the gluon fusion process, the alternative vector boson fusion is more sensitive to electroweak symmetry breaking through the gauge-Higgs couplings and therefore can be used to probe for models beyond the standard model. In this work, using the well known dijet-tagging technique to single out the vector boson fusion mechanism, we investigate its capability to discriminate a number of models that have been suggested to give an enhanced inclusive diphoton production rate, including the standard model Higgs boson, fermiophobic Higgs boson, Randall-Sundrum radion, inert-Higgs-doublet model, two-Higgs-doublet model, and the MSSM. The rates in vector-boson fusion can give more information of the underlying models to help distinguishing among the models.Comment: 31 pages, 3 figures; in this version some wordings are change

    Distribution and symmetrical patellofemoral pain patterns as revealed by high-resolution 3D body mapping:a cross-sectional study

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    Abstract Background Detailed pain mapping of extent and distribution in individuals with patellofemoral pain (PFP) within and around a complex structure such as the knee has yet to be explored. Methods Perceptions of on-going pain from adolescents and young adults (N = 35) with long-standing (>10Β months) PFP were collected on high-resolution 3D digital body-schema of the knees. Location, area of pain, pain intensity, laterality, worse side of knee pain, symptom duration, and symmetry in bilateral knee pain were recorded. A threshold for naturally occurring variations in symmetrical knee pain drawings were collected from 18 healthy controls and used in combination with the development a symmetry index (0–1) to create a fuzzy rule for classifying symmetrical and non-symmetrical PFP patterns as compared to a PFP expert. The symmetry index was computed and tested using a correlation coefficient alone or in combination with the Jaccard index and the true and false positive rates (TPR and FPR, respectively) determined. Results The peripatellar region was the common report of pain location however, novel and nonconforming PFP patterns were identified and the majority of individuals (22 of 27) with bilateral PFP expressed highly-symmetric mirror-image pain. Individuals with symptom duration of 5Β years or more had a greater area of pain, compared to those with symptoms for less than 5Β years. The total area of pain was correlated to symptom duration for those with extended symptoms durations and a progression towards an β€œO” shaped pattern emerged. A TPR of 100% for identifying symmetrical knee pain patterns was found however the expert PFP tended to be stricter, as reflected in FPR of 20%. Conclusions A high proportion of PFP patterns or symptoms occur in mirrored locations and are exceptionally symmetrical, and long duration of symptoms appear to converge to an β€˜O’ shape. Classifying symmetrical pain patterns is subjective however simple fuzzy rules and correlations can be used to increase objectivity. This study highlights a gap in knowledge of PFP symptom presentation, reveals what may be a natural progression of symptoms, and provides valuable clinical insight for both pain management and treatment

    Marimo machines: Oscillators, biosensors and actuators

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    BackgroundThe green algae balls (Aegagropila linnaei), known as Marimo, are large spherical colonies of live photosynthetic filaments, formed by rolling water currents in freshwater lakes. Photosynthesis therein produces gas bubbles that can attach to the Marimo, consequently changing its buoyancy. This property allows them to float in the presence of light and sink in its absence.ResultsWe demonstrate that this ability can be harnessed to make actuators, biosensors and bioprocessors (oscillator, logic gates). Factors affecting Marimo movement have been studied to enable the design, construction and testing of working prototypes.ConclusionsA novel actuator design is reported, incorporating an enhanced bubble retention system and the design and optimisation of a bio-oscillator is demonstrated. A range of logic gates (or, and, nor, nand, xor) implementable with Marimo have been proposed

    Endemicity response timelines for Plasmodium falciparum elimination

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    Background: The scaling up of malaria control and renewed calls for malaria eradication have raised interest in defining timelines for changes in malaria endemicity. Methods: The epidemiological theory for the decline in the Plasmodium falciparum parasite rate (PfPR, the prevalence of infection) following intervention was critically reviewed and where necessary extended to consider superinfection, heterogenous biting, and aging infections. Timelines for malaria control and elimination under different levels of intervention were then established using a wide range of candidate mathematical models. Analysis focused on the timelines from baseline to 1% and from 1% through the final stages of elimination. Results: The Ross-Macdonald model, which ignores superinfection, was used for planning during the Global Malaria Eradication Programme (GMEP). In models that consider superinfection, PfPR takes two to three years longer to reach 1% starting from a hyperendemic baseline, consistent with one of the few large-scale malaria control trials conducted in an African population with hyperendemic malaria. The time to elimination depends fundamentally upon the extent to which malaria transmission is interrupted and the size of the human population modelled. When the PfPR drops below 1%, almost all models predict similar and proportional declines in PfPR in consecutive years from 1% through to elimination and that the waiting time to reduce PfPR from 10% to 1% and from 1% to 0.1% are approximately equal, but the decay rate can increase over time if infections senesce. Conclusion: The theory described herein provides simple "rules of thumb" and likely time horizons for the impact of interventions for control and elimination. Starting from a hyperendemic baseline, the GMEP planning timelines, which were based on the Ross-Macdonald model with completely interrupted transmission, were inappropriate for setting endemicity timelines and they represent the most optimistic scenario for places with lower endemicity. Basic timelines from PfPR of 1% through elimination depend on population size and low-level transmission. These models provide a theoretical basis that can be further tailored to specific control and elimination scenarios

    Quantifying garnet-melt trace element partitioning using lattice-strain theory: New crystal-chemical and thermodynamic constraints

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    Many geochemical models of major igneous differentiation events on the Earth, the Moon, and Mars invoke the presence of garnet or its high-pressure majoritic equivalent as a residual phase, based on its ability to fractionate critical trace element pairs (Lu/Hf, U/Th, heavy REE/light REE). As a result, quantitative descriptions of mid-ocean ridge and hot spot magmatism, and lunar, martian, and terrestrial magma oceans require knowledge of garnet-melt partition coefficients over a wide range of conditions. In this contribution, we present new crystal-chemical and thermodynamic constraints on the partitioning of rare earth elements (REE), Y and Sc between garnet and anhydrous silicate melt as a function of pressure (P), temperature (T), and composition (X). Our approach is based on the interpretation of experimentally determined values of partition coefficients D using lattice-strain theory. In this and a companion paper (Draper and van Westrenen this issue) we derive new predictive equations for the ideal ionic radius of the dodecahedral garnet X-site,

    The use of schools for malaria surveillance and programme evaluation in Africa

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    Effective malaria control requires information on both the geographical distribution of malaria risk and the effectiveness of malaria interventions. The current standard for estimating malaria infection and impact indicators are household cluster surveys, but their complexity and expense preclude frequent and decentralized monitoring. This paper reviews the historical experience and current rationale for the use of schools and school children as a complementary, inexpensive framework for planning, monitoring and evaluating malaria control in Africa. Consideration is given to (i) the selection of schools; (ii) diagnosis of infection in schools; (iii) the representativeness of schools as a proxy of the communities they serve; and (iv) the increasing need to evaluate interventions delivered through schools. Finally, areas requiring further investigation are highlighted

    Adenovirus-5-Vectored P. falciparum Vaccine Expressing CSP and AMA1. Part B: Safety, Immunogenicity and Protective Efficacy of the CSP Component

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    Background: A protective malaria vaccine will likely need to elicit both cell-mediated and antibody responses. As adenovirus vaccine vectors induce both these responses in humans, a Phase 1/2a clinical trial was conducted to evaluate the efficacy of an adenovirus serotype 5-vectored malaria vaccine against sporozoite challenge.\ud \ud Methodology/Principal Findings: NMRC-MV-Ad-PfC is an adenovirus vector encoding the Plasmodium falciparum 3D7 circumsporozoite protein (CSP). It is one component of a two-component vaccine NMRC-M3V-Ad-PfCA consisting of one adenovector encoding CSP and one encoding apical membrane antigen-1 (AMA1) that was evaluated for safety and immunogenicity in an earlier study (see companion paper, Sedegah et al). Fourteen Ad5 seropositive or negative adults received two doses of NMRC-MV-Ad-PfC sixteen weeks apart, at 1x1010 particle units per dose. The vaccine was safe and well tolerated. All volunteers developed positive ELISpot responses by 28 days after the first immunization (geometric mean 272 spot forming cells/million[sfc/m]) that declined during the following 16 weeks and increased after the second dose to levels that in most cases were less than the initial peak (geometric mean 119 sfc/m). CD8+ predominated over CD4+ responses, as in the first clinical trial. Antibody responses were poor and like ELISpot responses increased after the second immunization but did not exceed the initial peak. Pre-existing neutralizing antibodies (NAb) to Ad5 did not affect the immunogenicity of the first dose, but the fold increase in NAb induced by the first dose was significantly associated with poorer antibody responses after the second dose, while ELISpot responses remained unaffected. When challenged by the bite of P. falciparum-infected mosquitoes, two of 11 volunteers showed a delay in the time to patency compared to infectivity controls, but no volunteers were sterilely protected.\ud \ud Significance: The NMRC-MV-Ad-PfC vaccine expressing CSP was safe and well tolerated given as two doses, but did not provide sterile protection
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