2,053 research outputs found

    Inhibition of monocyte complement receptor enhancement by low molecular weight material from human lung cancers

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    We have studied the effect of dialysates from lung cancer homogenates to alter both the expression of complement (C3b) receptors per se and also to inhibit leucoattractant-induced enhancement of complement rosettes on monocytes from healthy individuals. Enhancement and enhancement-inhibition by tumour extracts were compared with material derived from normal lung excised from distance from the tumour. There was no significant difference between tumour homogenate (TH) and normal lung homogenate (NLH) in terms of enhancement of complement rosettes per se. In contrast, TH produced a dose- and time-dependent inhibition of leucoattractant-induced enhancement of C3b rosettes which was significantly different from that obtained with NLH. This enhancement-inhibition was observed with four undifferentiated, four squamous and three adenocarcinomas of lung. The degree of enhancement-inhibition was not related to the type of tumour or varying accompanying histological features such as necrosis and the degree of infiltration with inflammatory cells. Following gel filtration on Sephadex G-50 each type of cancer gave a major peak of inhibitory activity which eluted with molecules having an apparent molecular size of approximately 3,000 daltons. A second larger peak (8,000-10,000 daltons) was also detected with extracts from the undifferentiated and adenocarcinomas. These results support previous findings, mainly from experimental animals, indicating that 'anti-macrophage/monocyte principles' are elaborated from certain tumour types

    Quantifying temporal and spatial variations in sediment, nitrogen and phosphorus transport in stream inflows to a large eutrophic lake

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    High-frequency sampling of two major stream inflows to a large eutrophic lake (Lake Rotorua, New Zealand) was conducted to measure inputs of total suspended sediment (TSS), and fractions of nitrogen and phosphorus (P). A total of 17 rain events were sampled, including three during which both streams were simultaneously monitored to quantify how concentration–discharge (Q) relationships varied between catchments during similar hydrological conditions. Dissolved inorganic nitrogen (DIN) concentrations declined slightly during events, reflecting dilution of groundwater inputs by rainfall, whereas dissolved inorganic P (PO₄–P) concentrations were variable and unrelated to Q, suggesting dynamic sorptive behaviour. Event loads of total nitrogen (TN) were predominantly DIN, which is available for immediate uptake by primary producers, whereas total phosphorus (TP) loads predominantly comprised particulate P (less labile). Positive correlations between Q and concentrations of TP (and to a lesser extent TN) reflected increased particulate nutrient concentrations at high flows. Consequently, load estimates based on hourly Q during storm events and concentrations of routine monthly samples (mostly base flow) under-estimated TN and TP loads by an average of 19% and 40% respectively. Hysteresis with Q was commonly observed and inclusion of hydrological variables that reflect Q history in regression models improved predictions of TN and TP concentrations. Lorenz curves describing the proportions of cumulative load versus cumulative time quantified temporal inequality in loading. In the two study streams, 50% of estimated two-year loads of TN, TP and TSS were transported in 202–207, 76–126 and 1–8 days respectively. This study quantifies how hydrological and landscape factors can interact to influence pollutant flux at the catchment scale and highlights the importance of including storm transfers in lake loading estimates

    Risk Factors for Hospital Admission After a Fall: A Prospective Cohort Study of Community-Dwelling Older People

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    Background: Falls in later life that require admission to hospital have well-established consequences for future disability and health. The likelihood and severity of a fall will result from the presence of one or more risk factors. The aim of this study is to examine risk factors identified for their ability to prevent falls and to assess whether they are associated with hospital admission after a fall. / Methods: Analyses of data from the English Longitudinal Study of Aging (ELSA), a prospective cohort study. In a sample of 3783 men and women older than 60 years old, a range of potential risk factors measured at Wave 4 (demographic, social environment, physical, and mental functioning) were examined as predictors of fall-related hospitalizations, identified using International Classification of Diseases, 10th Revision (ICD-10) code from linked hospital records in the United Kingdom. Subdistribution hazard models were used to account for competing risk of death. / Results: Several risk factors identified by previous work were confirmed. Suffering from urinary incontinence (subdistribution hazard ratio = 1.49; 95% CI: 1.14, 1.95) and osteoporosis (subdistribution hazard ratio = 1.48; 95% CI: 1.05, 2.07), which are not commonly considered at an early stage of screening, were found to be associated with hospital admission after a fall. Both low and moderate levels of physical activity were also found to somewhat increase the risk of hospital admission after a fall. / Conclusions: Several predictors of having a fall, severe enough to require hospital admission, have been confirmed. In particular, urinary incontinence should be considered at an earlier point in the assessment of risk

    Patterned Arrays of Supramolecular Microcapsules

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    Micropatterning of hydrogel has brought innovative outcomes in fundamental and applied material sciences. Previous approaches have mainly been dedicated to fabricate arrays of bulk hydrogel beads, which have inherent challenges including loading ability, scalability, specificity and versatility. Here we present a methodology to create hollow microcapsule arrays from sessile microdroplets. The difference in wettability between hydrophilic and hydrophobic surfaces enables self-partitioning of liquid into microdroplet arrays, serving as microreservoirs to load complementarily-functionalized host-guest polymers, cucurbit[8]uril-threaded highly-branched polyrotaxanes (HBP-CB[8]) and naphthyl-functionalized hydroxyethyl cellulose (HEC-Np). The interfacial dynamic complexation between positively-charged HBP-CB[8] and HECNp occurred in the presence of negatively-charged surfactants, resulting in condensed supramolecular hydrogel skins. The hydrogel microcapsules were uniform in size, and were developed to encapsulate target cargos in a robust and well-defined manner. Moreover, the microcapsule substrates were further used for surface enhanced Raman spectroscopy (SERS) sensing upon loading of gold nanoparticles. This facile assembly of microcapsule arrays has potential applications in controlled cargo delivery, bio-sensing, high throughput analysis and sorting

    A systematic review of simulation studies which compare existing statistical methods to account for non-compliance in randomised controlled trials

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    INTRODUCTION: Non-compliance is a common challenge for researchers and may reduce the power of an intention-to-treat analysis. Whilst a per protocol approach attempts to deal with this issue, it can result in biased estimates. Several methods to resolve this issue have been identified in previous reviews, but there is limited evidence supporting their use. This review aimed to identify simulation studies which compare such methods, assess the extent to which certain methods have been investigated and determine their performance under various scenarios.METHODS: A systematic search of several electronic databases including MEDLINE and Scopus was carried out from conception to 30th November 2022. Included papers were published in a peer-reviewed journal, readily available in the English language and focused on comparing relevant methods in a superiority randomised controlled trial under a simulation study. Articles were screened using these criteria and a predetermined extraction form used to identify relevant information. A quality assessment appraised the risk of bias in individual studies. Extracted data was synthesised using tables, figures and a narrative summary. Both screening and data extraction were performed by two independent reviewers with disagreements resolved by consensus.RESULTS: Of 2325 papers identified, 267 full texts were screened and 17 studies finally included. Twelve methods were identified across papers. Instrumental variable methods were commonly considered, but many authors found them to be biased in some settings. Non-compliance was generally assumed to be all-or-nothing and only occurring in the intervention group, although some methods considered it as time-varying. Simulation studies commonly varied the level and type of non-compliance and factors such as effect size and strength of confounding. The quality of papers was generally good, although some lacked detail and justification. Therefore, their conclusions were deemed to be less reliable.CONCLUSIONS: It is common for papers to consider instrumental variable methods but more studies are needed that consider G-methods and compare a wide range of methods in realistic scenarios. It is difficult to make conclusions about the best method to deal with non-compliance due to a limited body of evidence and the difficulty in combining results from independent simulation studies.PROSPERO REGISTRATION NUMBER: CRD42022370910.</p

    Surface superconducting states in a polycrystalline MgB2_{2} sample

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    We report results of dc magnetic and ac linear low-frequency study of a polycrystalline MgB2_2 sample. AC susceptibility measurements at low frequencies, performed under dc fields parallel to the sample surface, provide a clear evidence for surface superconducting states in MgB2_2.Comment: 4 pages and 5 figure

    The Importance of Meteorite Collections to Sample Return Missions: Past, Present, and Future Considerations

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    While much of the scientific community s current attention is drawn to sample return missions, it is the existing meteorite and cosmic dust collections that both provide the paradigms to be tested by these missions and the context for interpreting the results. Recent sample returns from the Stardust and Hayabusa missions provided us with new materials and insights about our Solar System history and processes. As an example, Stardust sampled CAIs among the population of cometary grains, requiring extensive and unexpected radial mixing in the early solar nebula. This finding would not have been possible, however, without extensive studies of meteoritic CAIs that established their high-temperature, inner Solar System formation. Samples returned by Stardust also revealed the first evidence of a cometary amino acid, a discovery that would not have been possible with current in situ flight instrument technology. The Hayabusa mission provided the final evidence linking ordinary chondrites and S asteroids, a hypothesis that developed from centuries of collection and laboratory and ground-based telescopic studies. In addition to these scientific findings, studies of existing meteorite collections have defined and refined the analytical techniques essential to studying returned samples. As an example, the fortuitous fall of the Allende CV3 and Murchison CM2 chondrites within months before the return of Apollo samples allowed testing of new state-of-the-art analytical facilities. The results of those studies not only prepared us to better study lunar materials, but unanticipated discoveries changed many of our concepts about the earliest history and processes of the solar nebula. This synergy between existing collections and future space exploration is certainly not limited to sample return missions. Laboratory studies confirmed the existence of meteorites from Mars and raised the provocative possibility of preservation of ancient microbial life. The laboratory studies in turn led to a new wave of Mars exploration that ultimately could lead to sample return focused on evidence for past or present life. This partnership between collections and missions will be increasingly important in the coming decades as we discover new questions to be addressed and identify targets for for both robotic and human exploration . Nowhere is this more true than in the ultimate search for the abiotic and biotic processes that produced life. Existing collections also provide the essential materials for developing and testing new analytical schemes to detect the rare markers of life and distinguish them from abiotic processes. Large collections of meteorites and the new types being identified within these collections, which come to us at a fraction of the cost of a sample return mission, will continue to shape the objectives of future missions and provide new ways of interpreting returned samples

    The AMIGA sample of isolated galaxies. V. Quantification of the isolation

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    The AMIGA project aims to build a well defined and statistically significant reference sample of isolated galaxies in order to estimate the environmental effects on the formation and evolution of galaxies. The goal of this paper is to provide a measure of the environment of the isolated galaxies in the AMIGA sample, quantifying the influence of the candidate neighbours identified in our previous work and their potential effects on the evolution of the primary galaxies. Here we provide a quantification of the isolation degree of the galaxies in this sample. Our starting sample is the Catalogue of Isolated Galaxies (CIG). We used two parameters to estimate the influence exerted by the neighbour galaxies on the CIG galaxy: the local number density of neighbour galaxies and the tidal strength affecting the CIG galaxy. We show that both parameters together provide a comprehensive picture of the environment. For comparison, those parameters have also been derived for galaxies in denser environments such as triplets, groups and clusters. The CIG galaxies show a continuous spectrum of isolation, as quantified by the two parameters, from very isolated to interacting. The fraction of CIG galaxies whose properties are expected to be influenced by the environment is however low (159 out of 950 galaxies). The isolated parameters derived for the comparsion samples gave higher values than for the CIG and we found clear differences for the average values of the 4 samples considered, proving the sensitivity of these parameters. The environment of the galaxies in the CIG has been characterised, using two complementary parameters quantifying the isolation degree, the local number density of the neighbour galaxies and the tidal forces affecting the isolated galaxies. (Abridged)Comment: 10 pages, 12 figures, proposed for acceptance A&

    Ruptured splenic artery aneurysms and the use of an adapted fast protocol in reproductive age women with hemodynamic collapse: Case series

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    Nontraumatic symptomatic hypotension in all patients requires prompt diagnosis and appropriate treatment for optimum outcome. The female population specifically has an expanded differential diagnosis that should be considered when these patients present with hemodynamic collapse. While the most common causes of hypotension in pregnant patients are dehydration, ruptured ectopic pregnancy, and placental and uterine abnormalities, less common nonobstetrical etiologies such as hepatic rupture and ruptured abdominal and visceral artery aneurysms should also be considered. Splenic artery aneurysms are associated with high rates of mortality and in cases of pregnancy, maternal and fetal mortality. These high rates can be attributed to the asymptomatic nature of the aneurysm, rapid deterioration after rupture, and frequent misdiagnosis. In patients with hemodynamic collapse, the role of traditional imaging is limited mainly due to the critical condition of the patient. Bedside ultrasound has emerged as a diagnostic imaging resource in patients with undifferentiated hypotension and in patients with traumatic injuries. However, its use has not been studied specifically in the female population. We present two patients with ruptured splenic artery aneurysms, discuss the role of bedside ultrasound in their management, and introduce a new ultrasound protocol for use in reproductive age female patients with hemodynamic collapse
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