341 research outputs found

    Competitive adsorption of plasma proteins at solid—liquid interfaces

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    The competitive adsorption of human serum albumin (HSA), human immuno-γ-globulin (HIgG) and human fibrinogen (HFb) onto polystyrene (PS) at 20° C and a pH of 7.35 (phosphate-buffered saline) was studied. Protein adsorption was studied using enzyme immunoassay. The results obtained with the immunoassay were compared with those obtained using radiolabelled proteins. Recent studies revealed that the adsorption behaviour of radiolabelled proteins onto surfaces differs from that of the non-labelled proteins, which may lead to misinterpretation of adsorption data. Differences in the adsorption behaviour of the labelled proteins as compared to non-labelled proteins can possibly be explained by the formation of modified proteins during the labelling procedure as shown by ion-exchange high-performance liquid chromatography (HPLC). The competitive adsorption of HSA, HIgG and HFb onto a PS latex was studied by measuring the depletion of proteins in solution. The decrease in protein concentration in solution was determined by HPLC techniques. A strong preferential adsorption of HFb was observed with maximum adsorption values of 0.6 μg/cm2

    The adsorption behaviour of two commercial IgG-preparations onto a polystyrene latex surface

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    The adsorption behaviour of two commercial preparations of human IgG onto a polystyrene latex surface was studied. The adsorption isotherms obtained differed markedly, one preparation showed a plateau value of 0.4 μg cm−2 which was reached at 0.1g I−1, whereas the other preparation showed no plateau value within the concentration range studied (0.1–7.0 g I−1). Characterization by means of iso-electric focusing and HPLC also showed differences between the two preparations. No differences were observed when immuno-electrophoresis was carried out These results stress the necessity for proper characterization of proteins used in adsorption studies

    What do women undergoing in vitro fertilization (IVF) understand about their chance of IVF success?

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    Funding No external funding was used for this study. S.L. is supported by a NHMRC Investigator Grant (APP1195189). R.W. is supported by a NHMRC Investigator Grant (GNT2009767). B.W.M. is supported by a NHMRC Investigator Grant (GNT1176437) and has received research funding and travel funding from MerckPeer reviewedPublisher PD

    Modulating calcium phosphate formation using CO2 laser engineering of a polymeric material

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    The use of simulated body fluid (SBF) is widely used as a screening technique to assess the ability of materials to promote calcium phosphate formation. This paper details the use of CO2 laser surface treatment of nylon® 6,6 to modulate calcium phosphate formation following immersion in SBF for 14 days. Through white light interferometry (WLI) it was determined that the laser surface processing gave rise to maximum Ra and Sa parameters of 1.3 and 4.4 µm, respectively. The use of X-ray photoelectron spectroscopy (XPS) enabled a maximum increase in surface oxygen content of 5.6 %at. to be identified. The laser-induced surface modifications gave rise to a modulation in the wettability characteristics such that the contact angle, θ, decreased for the whole area processed samples, as expected, and increased for the patterned samples. The increase in θ can be attributed to a transition in wetting nature to a mixed-state wetting regime. It was seen for all samples that calcium phosphate formed on each surface following 14 days. The largest increase in mass, Δg, owed to calcium phosphate formation, was brought about by the whole area processed sample irradiated with a fluence of 51 Jcm-2. No correlation between the calcium phosphate formation and the laser patterned surface properties was determined due to the likely affect of the mixed-state wetting regime. Strong correlations between θ, the surface energy parameters and the calcium phosphate formation for the whole area processed samples allow one to realize the potential for this surface treatment technique in predicting the bone forming ability of laser processed materials

    Wettability and osteoblast cell response modulation through UV laser processing of nylon 6,6

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    With an ageing population the demand for cheap, efficient implants is ever increasing. Laser surface treatment offers a unique means of varying biomimetic properties to determine generic parameters to predict cell responses. This paper details how a KrF excimer laser can be employed for both laser-induced patterning and whole area irradiative processing to modulate the wettability characteristics and osteoblast cell response following 24 hour and 4 day incubation. Through white light interferometry (WLI) it was found that the surface roughness had considerably increased by up to 1.5 µm for the laser-induced patterned samples and remained somewhat constant at around 0.1 µm for the whole area irradiative processed samples. A sessile drop device determined that the wettability characteristics differed between the surface treatments. For the patterned samples the contact angle, θ, increased by up to 25° which can be attributed to a mixed-state wetting regime. For the whole area irradiative processed samples θ decreased owed to an increase in polar component, γP. For all samples θ was a decreasing function of the surface energy. The laser whole area irradiative processed samples gave rise to a distinct correlative trend between the cell response, θ and γP. However, no strong relationship was determined for the laser-induced patterned samples due to the mixed-state wetting regime. As a result, owed to the relationships and evidence of cell differentiation one can deduce that laser whole area irradiative processing is an attractive technology for employment within regenerative medicine to meet the demands of an ageing population

    Why are feasibility studies accessing routinely collected health data? A systematic review

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    BACKGROUND: Feasibility trials are often undertaken to determine whether a larger randomised controlled trial (RCT) is achievable. In a recent review, 15 feasibility trials accessed routinely collected health data (RCHD) from UK national databases and registries. This paper looks at attributes of these trials and the reasons why they accessed RCHD. METHODS: We extracted data from all publicly available sources for the 15 feasibility studies found in a previous review of trials successfully accessing RCHD in the UK between 2013–2018 for the purpose of informing or supplementing participant data. We extracted trial characteristics, the registry accessed, and the way the RCHD was used. RESULTS: The 15 feasibility RCTs were conducted in a variety of disease areas, and were generally small (median sample size 100, range 41–4061) and individually randomised (60%, 9/15). The primary trial outcome was predominantly administrative (non-clinical) (80%, 12/15) such as feasibility of patient recruitment. They were more likely to recruit from secondary care (67%, 10/15) settings than primary (33%, 5/15). NHS Digital was the most commonly accessed registry (33% (5/15)) with SAIL databank (20% (3/15)), electronic Data Research and Innovation Service (eDRIS) and Paediatric Intensive Care Audit Network (PICANET) (each 13% 2/15) also being accessed. Where the information was clear, the trials used RCHD for data collection during the trial (47%, 7/15), follow-up after the trial (27%, 4/15) and recruitment (13%, 2/15). CONCLUSIONS: Between 2013 and 2018, 15 feasibility trials successfully accessed UK RCHD. Feasibility trials would benefit, as with other trials, from guidance on reporting the use of RCHD in protocols and publications

    Should vascular wall F-18-FDG uptake be adjusted for the extent of atherosclerotic burden?

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    Vascular wall 18F-FDG uptake is often used as a surrogate marker of atherosclerotic plaque inflammation. A potential caveat is that vascular wall 18F-FDG uptake is higher simply because more atherosclerosis is present. To determine if the degree of inflammation is high or low relative to the extent of atherosclerosis, vascular wall 18F-FDG uptake may require statistical adjustment for a non-inflammatory marker reflecting the extent of atherosclerosis, e.g. calcification. Adjustments is probably needed if (1) vascular wall 18F-FDG uptake correlates sufficiently strongly with arterial calcification and (2) adjustment for extent of calcification affects determinants of vascular 18F-FDG uptake. This study addresses these questions. 18F-FDG PET/low-dose-CT scans of 99 patients were used. Cardiovascular risk factors were assessed and PET/CT scans were analysed for standardized 18F-FDG uptake values and calcification. ANOVA was used to establish the association between vascular 18F-FDG uptake and calcification. Multiple linear regression (with and without calcification as independent variable) was used to show whether determinants of vascular 18F-FDG uptake were affected by the degree of calcification. 18F-FDG uptake was related to increased calcification in the aortic arch, descending and abdominal aorta. However, 18F-FDG uptake showed considerable overlap between categories of calcification. Age and body mass index were main determinants of vascular 18F-FDG uptake. In multiple regression analyses, most standardized beta coefficients of these determinants were not affected by adjustment for the degree of calcification. Although vascular 18F-FDG uptake is related to total atherosclerotic burden, as reflected by vascular calcification, the association is weak and unlikely to affect the identification of determinants of atherosclerotic inflammation implicating no need for adjustment in future studies

    Mindfulness-based stress reduction for elementary school teachers: a randomized controlled trial

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    Educators frequently grapple with elevated levels of job-related stress, heightening the risk of mental health issues. Although Mindfulness-Based Stress Reduction (MBSR) has demonstrated effectiveness in reducing stress among the general populace, its implementation among educators, especially in non-United States settings, has received limited exploration. This pre-registered randomized-controlled trial investigates the effectiveness of the standard MBSR in reducing perceived stress among Dutch elementary school teachers. Additionally, it examines the impact of MBSR on mindfulness skills, emotion regulation, and self-compassion as secondary proximal outcomes, along with exploring its influence on teacher self-efficacy, perceived pupil-teacher relationships, and classroom climate quality as secondary distal outcomes. Involving 146 teachers randomly assigned to either the intervention (n = 72) or waitlist-control condition (n = 74), assessments were conducted pre- and post-intervention or control period, with a 3-month follow-up. Participants in the intervention reported significantly lower perceived stress compared to the control group, demonstrating a substantial effect size at post-treatment (d = −0.84) and a moderate effect at follow-up (d = −0.69). MBSR not only yielded improvements in personal well-being but also positively impacted teacher self-efficacy and classroom climate quality at both post-treatment and follow-up. These positive outcomes aligned with enhancements in mindfulness skills, emotion regulation, and self-compassion. However, no significant effects were observed on the pupil-teacher relationship. Exploratory analyses revealed no moderation effects based on past or present psychological problems, school weight/pupil population, years of experience, or age on perceived stress at post-measurement. Furthermore, the study examined the potential influence of COVID-19 on the results, concluding that the pandemic had no discernible impact. These findings advocate for the widespread adoption of the standard MBSR program as a means of enhancing the well-being of elementary school teachers

    Community awareness and use of anti-Müllerian hormone testing in Australia : a population survey of women

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    Funding This project was supported by a National Health and Medical Research Council (NHMRC) Centre for Research Excellence grant (1104136) and Program grant (1113532). T.C. is supported by an NHMRC Emerging Leader Research Fellowship (2009419).Peer reviewedPublisher PD
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