The behaviour of anodically-polarised magnesium (Mg) appears counter-intuitive to conventional electrochemical theory, where the application of increasingly positive potentials or higher currents ...produce progressively greater rates of hydrogen evolution. Presently this observation is explained by a theory involving Mg dissolution through a Mg+ intermediate, which undergoes chemical reaction with water to produce hydrogen. Here we report the use of an in-situ scanning vibrating electrode technique (SVET) to characterise local current density distributions over anodically-polarised Mg surfaces immersed in sodium chloride containing electrolyte. Anodic dissolution is shown to be highly localised in nature and accompanied by significant cathodic activity. The area occupied by local cathodes increases with time and both total anodic and cathodic currents emerging from the exposed Mg surface are shown to rise accordingly. It is also demonstrated that increasing the anodic current supplied to the Mg causes local cathode areas to grow more rapidly, hence accounting for progressively greater hydrogen evolution rates. These observations demonstrate that hydrogen evolution remains a cathodic process, thus invalidating the Mg+ theory of dissolution.
•Anodically polarised pure Mg surfaces studied by scanning vibrating electrode.•Anodic dissolution is highly focal and accompanied by significant cathodic activity.•Cathode area increases with time and grows more rapidly at higher applied current.•Total anodic current increases with time as more cathode area becomes exposed.•A mechanism based on an Mg+ intermediate is not required to explain the results.
Bisphosphonate-related osteonecrosis of the jaw (BRONJ) commonly occurs in individuals receiving bisphosphonates (BPs) with clinical manifestations of the exposed necrotic bone. Although defective ...wound healing of soft tissue is frequently, if not always, observed in BRONJ, the effects of BPs on oral soft tissue or cells remain unknown. To investigate the effects of BPs on cells of oral mucosal tissue, we studied the effect of pamidronate (PAM), one of the BPs most commonly administered to cancer patients, on the phenotypes of normal human oral keratinocytes (NHOK) and fibroblasts (NHOF). When exposed to PAM at 10 µM, NHOK, not NHOF, underwent senescence: NHOK overexpressed senescence-associated β-galactosidase (SA-β-Gal), p16INK4A, IL-6, and IL-8. When exposed to a higher level (50 µM) of PAM, NHOK maintained senescent phenotypes, but NHOF underwent apoptosis. PAM-induced senescence in NHOK is mediated, in part, via geranylgeranylation of the mevalonate pathway. Our in vitro 3D oral mucosal tissue construction studies further demonstrated that PAM induced senescence and impaired re-epithelialization of oral mucosa. Analysis of these data indicates that premature senescence of oral mucosal cells and subsequent defective soft-tissue wound healing might be partly responsible for the development of BRONJ in individuals receiving PAM or other BPs.
Some individuals are endowed with a biology that renders them more reactive to novelty and potential threat. When extreme, this anxious temperament (AT) confers elevated risk for the development of ...anxiety, depression and substance abuse. These disorders are highly prevalent, debilitating and can be challenging to treat. The high-risk AT phenotype is expressed similarly in children and young monkeys and mechanistic work demonstrates that the central (Ce) nucleus of the amygdala is an important substrate. Although it is widely believed that the flow of information across the structural network connecting the Ce nucleus to other brain regions underlies primates' capacity for flexibly regulating anxiety, the functional architecture of this network has remained poorly understood. Here we used functional magnetic resonance imaging (fMRI) in anesthetized young monkeys and quietly resting children with anxiety disorders to identify an evolutionarily conserved pattern of functional connectivity relevant to early-life anxiety. Across primate species and levels of awareness, reduced functional connectivity between the dorsolateral prefrontal cortex, a region thought to play a central role in the control of cognition and emotion, and the Ce nucleus was associated with increased anxiety assessed outside the scanner. Importantly, high-resolution 18-fluorodeoxyglucose positron emission tomography imaging provided evidence that elevated Ce nucleus metabolism statistically mediates the association between prefrontal-amygdalar connectivity and elevated anxiety. These results provide new clues about the brain network underlying extreme early-life anxiety and set the stage for mechanistic work aimed at developing improved interventions for pediatric anxiety.
An
in situ Scanning Vibrating Electrode Technique (SVET) is used to investigate the inhibition of localised corrosion occurring on unpolarised magnesium (Mg) samples immersed in 5% (w/v) aqueous ...sodium chloride electrolyte. In uninhibited electrolyte, localised corrosion features taking the form of dark, radially expanding discs are shown to consist of a strongly cathodic interior, surrounded by a ring of anodic activity. A range of potential anionic inhibitors, selected on the basis of their ability to form insoluble precipitates with aqueous Mg
2+ ions, are systematically investigated and compared with chromate additions. Of the anions evaluated only phosphate additions markedly decrease the extent of localised corrosion observed and provide a comparable level of inhibition to chromate. The onset of profound corrosion inhibition is achieved at threshold concentrations of 10
−2 and 2
×
10
−4
mol
dm
−3 for chromate and phosphate additions respectively. Phosphate inhibition efficiency increases markedly when the pH of the electrolyte is decreased. Consequently at phosphate concentrations of ≥10
−3
mol
dm
−3, in the pH 4–7 range, Mg is able to withstand over 4
h immersion with little evidence of breakdown. From the empirical evidence presented, it is proposed that phosphate principally acts to inhibit hydrogen evolution at focal cathodic sites, where elevated pH produces sufficient PO
4
3− speciation to form a surface precipitate by combining with free Mg
2+.
The global organic aerosol (OA) budget is highly uncertain and past studies suggest that models substantially underestimate observed concentrations. Few of these studies have examined the vertical ...distribution of OA. Furthermore, many model-measurement comparisons have been performed with different models for single field campaigns. We synthesize organic aerosol measurements from 17 aircraft campaigns from 2001–2009 and use these observations to consistently evaluate a GEOS-Chem model simulation. Remote, polluted and fire-influenced conditions are all represented in this extensive dataset. Mean observed OA concentrations range from 0.2–8.2 μg sm−3 and make up 15 to 70% of non-refractory aerosol. The standard GEOS-Chem simulation reproduces the observed vertical profile, although observations are underestimated in 13 of the 17 field campaigns (the median observed to simulated ratio ranges from 0.4 to 4.2), with the largest model bias in anthropogenic regions. However, the model is best able to capture the observed variability in these anthropogenically-influenced regions (R2=0.18−0.57), but has little skill in remote or fire-influenced regions. The model bias increases as a function of relative humidity for 11 of the campaigns, possibly indicative of missing aqueous phase SOA production. However, model simulations of aqueous phase SOA suggest a pronounced signature in the mid-troposphere (2–6 km) which is not supported in the observations examined here. Spracklen et al. (2011) suggest adding ~100 Tg yr−1 source of anthropogenically-controlled SOA to close the measurement-model gap, which we add as anthropogenic SOA. This eliminates the model underestimate near source, but leads to overestimates aloft in a few regions and in remote regions, suggesting either additional sinks of OA or higher volatility aerosol at colder temperatures. Sensitivity simulations indicate that fragmentation of organics upon either heterogeneous or gas-phase oxidation could be an important (missing) sink of OA in models, reducing the global SOA burden by 15% and 47% respectively. The best agreement with observations is obtained when the simulated anthropogenically-controlled SOA is increased to ~100 Tg yr−1 accompanied by either a gas-phase fragmentation process or a reduction in the temperature dependence of the organic aerosol partitioning (by decreasing the enthalpy of vaporization from 42 kJ mol−1 to 25 kJ mol−1). These results illustrate that models may require both additional sources and additional sinks to capture the observed concentrations of organic aerosol.
The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft landed successfully on Mars and imaged the surface to characterize the surficial geology. Here ...we report on the geology and subsurface structure of the landing site to aid in situ geophysical investigations. InSight landed in a degraded impact crater in Elysium Planitia on a smooth sandy, granule- and pebble-rich surface with few rocks. Superposed impact craters are common and eolian bedforms are sparse. During landing, pulsed retrorockets modified the surface to reveal a near surface stratigraphy of surficial dust, over thin unconsolidated sand, underlain by a variable thickness duricrust, with poorly sorted, unconsolidated sand with rocks beneath. Impact, eolian, and mass wasting processes have dominantly modified the surface. Surface observations are consistent with expectations made from remote sensing data prior to landing indicating a surface composed of an impact-fragmented regolith overlying basaltic lava flows.
Telemedicine services have been increasingly used to facilitate post-treatment cancer survivorship care, including improving access; monitoring health status, health behaviors, and symptom ...management; enhancing information exchange; and mitigating the costs of care delivery, especially since the COVID-19 pandemic. To inform guidance for the use of telemedicine in the post-COVID era, the aim of this overview of systematic reviews (SRs) was to evaluate the efficacy of, and survivor engagement in, telemedicine interventions in the post-treatment survivorship phase, and to consider implementation barriers and facilitators.
PubMed, Cochrane CENTRAL, CINAHL, Embase, and Web of Science databases were searched. SRs that examined the use of telemedicine in the post-treatment phase of cancer survivorship, published between January 2010 and April 2021, were included. Efficacy data were synthesized narratively. Implementation barriers and facilitators were synthesized using the Consolidated Framework for Implementation Research.
Twenty-nine SRs were included. A substantive body of evidence found telemedicine to benefit the management of psychosocial and physical effects, particularly for improving fatigue and cognitive function. There was a lack of evidence on the use of telemedicine in the prevention and surveillance for recurrences and new cancers as well as management of chronic medical conditions. This overview highlights a range of diverse barriers and facilitators at the patient, health service, and system levels.
This review highlights the benefits of telemedicine in addressing psychosocial and physical effects, but not in other areas of post-treatment cancer survivorship care. This large review provides practical guidance for use of telemedicine in post-treatment survivorship care.
•Telemedicine interventions can be effective for addressing the psychosocial and physical effects of cancer.•Development of evidence-based guidance for the implementation of telemedicine in survivorship care is urgently required.•Rigorous studies exploring strategies to improve telemedicine accessibility to diverse population groups are warranted.
The objective of this study was to investigate the relationships among birth weight, birth order, or litter size on growth performance, carcass quality, and eating quality of the ultimate pork ...product. Data were collected from 98 pig litters and, with the addition of recording birth weight and birth order, farrowing and piglet management were according to normal barn practices. In the nursery and during growout, the pigs received the normal feeding program for the barn and, with the addition of individual tattooing, were marketed as per standard procedure. From 24 litters, selected because they had at least 12 pigs born alive and represented a range of birth weights, 4 piglets were chosen (for a total of 96 piglets) and sent to Agriculture and Agri-Food Canada-Lacombe Research Centre (Lacombe, Alberta, Canada) when they reached 120 kg for extensive meat quality and sensory analysis. Individual BW was measured at birth, on the day of weaning, 5 wk after weaning, at nursery exit, at first pull, and at the time of marketing. Litter sizes were divided into 3 categories: small (3 to 10 piglets), medium (11 to 13 piglets), and large (14 to 19 piglets). There were 4 birth-weight quartiles: 0.80 to 1.20, 1.25 to 1.45, 1.50 to 1.70, and 1.75 to 2.50 kg. Increased litter size resulted in reduced mean birth weight (P < 0.05), but had no effect on within litter variability or carcass quality (P > 0.05) when slaughtered at the same endpoint. Lighter birth-weight pigs had reduced BW at weaning, 5 and 7 wk postweaning, and at first pull and had increased days to market (P < 0.05). Birth weight had limited effects on carcass quality, weight of primal cuts, objective quality, and overall palatability of the meat at the same slaughter weight (P > 0.05). In conclusion, increased litter size resulted in decreased mean birth weight but no change in days to market. Lighter birth-weight pigs took longer to reach market. Despite some differences in histological properties, birth weight had limited effects on carcass composition or final eating quality of the pork when slaughtered at the same BW and large litter size resulted in more pigs weaned and marketed compared with the smaller litters. We concluded that based on the conditions of this study, other than increased days to market, there is no reason based on pig performance or pork quality to slow down the goal of the pork industry to increase sow productivity as a means to increase efficiency.
•Immersion of Zn-Al-Mg coatings of varying composition and thickness in acetic acid.•Substrate iron exposure time increases with Zn-Al-Mg thickness and Al content.•Filiform corroded area rate ...increases with coating thickness and Al (≤6 wt. %).•Filiform propagation rate determined by time to iron exposure.•Modification in coating composition can reduce rate of filiform corrosion.
The effect of coating thickness and composition on the kinetics of acetic acid-induced filiform corrosion (FFC) on Zinc-Aluminium-Magnesium (ZAM) coated steel is investigated. Scribe defects are created in organic coatings applied to ∼10 μm coatings of varying composition (1−6 wt.%. Al, 1−3 wt. % Mg), and fixed composition (Zn-1.5 wt. % Al- 1.5 wt.% Mg) but varying thickness (5−27 μm). FCC decreases with increasing Al (at fixed wt. % Mg) and thickness. A linear trend exists between thickness and iron exposure time. Findings are consistent with FFC advancing via a penetrative coating mechanism whereby exposed iron couples to the coating.
Comorbid conditions appear to be common among individuals hospitalised with coronavirus disease 2019 (COVID-19) but estimates of prevalence vary and little is known about the prior medication use of ...patients. Here, we describe the characteristics of adults hospitalised with COVID-19 and compare them with influenza patients. We include 34,128 (US: 8362, South Korea: 7341, Spain: 18,425) COVID-19 patients, summarising between 4811 and 11,643 unique aggregate characteristics. COVID-19 patients have been majority male in the US and Spain, but predominantly female in South Korea. Age profiles vary across data sources. Compared to 84,585 individuals hospitalised with influenza in 2014-19, COVID-19 patients have more typically been male, younger, and with fewer comorbidities and lower medication use. While protecting groups vulnerable to influenza is likely a useful starting point in the response to COVID-19, strategies will likely need to be broadened to reflect the particular characteristics of individuals being hospitalised with COVID-19.
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