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Development of primary cell cultures from haplochromine cichlid bone-derived tissues
Get PDFBone is a dynamic tissue with ecological and evolutionary importance, as it can grow and remodel itself in response to mechanical stimuli. In mammals, osteocytes are widely recognised as the central regulators of bone formation and mechanotransduction. However, many advanced teleosts lack these cells yet still exhibit evidence of bone formation and remodelling. This challenges the prevailing view that osteocytes are indispensable for these processes. Notably, these anosteocytic teleosts exhibit clear responses to mechanical loading, suggesting alternative mechanisms at play. African cichlids, known for their remarkable ecological diversification, which occurs in craniofacial bone morphology. However, these differences are based on very few genetic changes, while including interspecific variation in bone remodeling capacities. Thus, cichlid, being anosteocytic, and variable in remodeling abilities based on very few genetic changes, represents an ideal model system for understanding the mechanisms underlying remodeling. This protocol outlines the development of primary cell cultures from cichlid jaw bones that can be applied across species, establishing a foundation for future research aimed at elucidating the cellular and molecular mechanisms underlying bone formation and remodelling in anosteocytic systems
Demographic pressure as a factor in inter-ethnic conflicts: evidence from Colombia
Get PDFThis article explores the link between demographic pressure and inter-ethnic conflicts. Relying on a mixed-methods approach applied to the paradigmatic case of the Cauca region of Colombia, we argue that demographic pressure can play an important role in explaining a recent wave of conflicts between indigenous, mestizo peasant and Afro-Colombian communities. We find that increasing population density within indigenous territories (resguardos) increases the probability of conflict, and that this effect is most acute in resguardos with limited agricultural area. We also describe the complexities of claims and strategies linked to these conflicts and the impact on social relationships and livelihoods. We advocate for a more holistic understanding of land struggles, one that moves the discussion beyond territorial recognition for indigenous peoples and engages with the multiple challenges ethnic communities are facing, including demographic pressure, land scarcity, environmental fragility and endemic poverty and marginalization
Effect of fibre orientation of adjacent plies on the mode I delamination fracture of carbon fibre reinforced polymer multidirectional laminates
Get PDFThe extensive use of multidirectional composite laminates requires to understand the delamination behavior at interfaces between plies with different fiber orientations. In this study, double cantilever beam testing was performed to investigate the mode I interlaminar fracture of carbon fiber reinforced polymer laminates with different central interfaces (0//0, 0//+45 and +45//−45). X-ray microtomography revealed the curved crack front shape that was incorporated to calculate fracture toughness. The fracture toughness varies with the crack length in a typical delamination resistance curve, which can be quantified by an empirical equation. Incorporation of variable fracture toughness into a cohesive zone model can better predict the delamination fracture of the laminate, compared to constant toughness. It was found that the delamination mechanism is independent of central interfaces. However, compared to unidirectional laminates, multidirectional laminates are less resistant to crack initiation, but more resistant to propagation with higher toughness and shorter fiber bridging zone.
Highlights:
Mode I interlaminar fracture of CFRP laminates with different central interfaces was investigated experimentally and numerically;
Curved crack front shape was incorporated to calculate fracture toughness;
Incorporation of variable fracture toughness into a cohesive zone model can better predict the delamination fracture of the laminate;
Multidirectional laminates are less resistant to crack initiation but more resistant to propagation with higher toughness and shorter fiber bridging zone
Frailty and the survival outcomes of patients with laryngeal squamous cell cancer
Get PDFBackground:
Frailty increases the risk of mortality in the head and neck cancer population. This study examines the association between frailty and survival outcomes in patients with laryngeal squamous cell cancer (LSCC).
Method:
Retrospective data collection from patients in the West of Scotland diagnosed with LSCC between 2014 and 2020. The Modified Five Item Frailty Index (mFI-5) measures frailty and categorizes patients according to their level of frailty. Statistical tests used were the Mann–Whitney U-test or ANOVA for differences in means and survival analyses for overall survival time.
Results:
There were 867 patients included. Seventy-eight percent (n = 676) of patients were deemed frail. Median survival for “not frail” patients was 78 months and “severely frail” was 23 months. The palliative treatment group had worse overall survival outcomes compared to curative (hazard ratio (HR) of 7.96, p < 0.001).
Conclusion:
This study demonstrates frailty is common in patients with LSCC and leads to worse mortality and survival outcomes
Efficacy of air cleaning units for preventing SARS-CoV-2 and other hospital-acquired infections on medicine for older people wards: a quasi-experimental controlled before-and-after study
Get PDFBackground:
Nosocomial infections are costly and airborne transmission is increasingly recognised as important for spread. Air Cleaning Units (ACUs) may reduce transmission but little research has focused on their effectiveness on open wards.
Aim:
Assess whether ACUs reduce nosocomial SARS-CoV-2, or other, infections on older adult inpatient wards.
Methods:
Quasi-experimental before-after study on two intervention-control ward pairs in a UK teaching hospital. Infections were identified using routinely collected electronic health records data during one year of ACU implementation and the preceding year (“core study period”). Extended analyses included 6 months additional data from one ward pair following ACU removal. Hazard ratios (HR) were estimated through Cox regression controlling for age, sex, ward and background infection risk. Time the ACUs were switched on was also recorded for intervention ward 2.
Findings:
ACUs were initially feasible but compliance reduced towards the end of the study (average operation in first vs second half of ACU time on intervention ward 2: 77% vs 53%). 8171 admissions >48hrs (6112 patients, median age 85yrs) were included. Overall, incidence of ward-acquired SARS-CoV-2 was 3.8%. ACU implementation was associated with a non-significant trend of lower hazard for SARS-CoV-2 infection (HR core study period 0.90, 95% CI 0.53, 1.52; extended study period 0.78, 95% CI 0.53, 1.14). Only 1.5% of admissions resulted in other notable ward-acquired infections.
Conclusion:
ACUs may reduce SARS-CoV-2 infection to a clinically-meaningfully degree. Larger studies could reduce uncertainty, perhaps using a cross-over design, and factors influencing acceptability to staff and patients should be further explored
Explanations for higher-than-expected mortality from April 2021: a scoping review
Get PDFObjectives:
Many countries have continued to experience a higher-than-expected number of deaths following the peaks in mortality observed in the first year of the Covid-19 pandemic. This review aims to identify the different explanations proposed for sustained higher-than-expected mortality beyond the first pandemic year.
Study design:
Scoping review.
Methods:
A systematic search of databases and grey literature sources was completed to identify English-language records proposing or investigating hypotheses for higher-than-expected mortality from April 2021 onwards in (sub)populations of high-income countries. Papers focused on survival following a diagnosis or intervention were excluded. Results were summarised narratively, and existing research prioritisation frameworks were adapted and applied to identify priorities for further research within a UK context.
Results:
Seventy eligible papers were identified. Most were opinion pieces or simply presented trends; few included investigation of suggested hypotheses. Numerous explanations for higher-than-expected mortality were proposed, with hypotheses relating to direct Covid-19 mortality, sequalae of Covid-19 infection, the health service and wider impacts of the pandemic, and socioeconomic factors identified as highest-priority for further research.
Conclusions:
A critical understanding of the causes of higher-than-expected mortality is essential for achieving evidence-informed policy. This review proposes priorities for further research, although these are based on author opinion only and likely to vary by setting. We did not seek to clarify the potential interactions between the hypotheses identified, however, in the UK, it is likely that the wider impacts of the Covid-19 pandemic on socioeconomic conditions have exacerbated pre-existing austerity-related trends in stalling life expectancy
Shaping the narrative: examining news coverage of voter ID laws in the United States
Get PDFThis study is the first to examine US news coverage of voter ID laws. Voter ID requirements are central to ongoing political debates about voting procedures. Despite rare cases of voter fraud by impersonation and the strong polarization over voter ID among partisan elites, there is a surprising broad bipartisan support for voter ID among the American public. Using a range of inductive computational content analysis methods, we analyse news coverage of voter ID requirements from 2013 to 2023. We find coverage differs by outlets political leaning and demonstrate a link between news media discourse and elite framing on the issue. Donald Trump’s voter fraud allegations, however, appear to have substantially shaped left-leaning media coverage from 2016, raising concerns around whether this might have helped amplify electoral conspiracies, instead of offering the public alternative ways of thinking about voter ID laws
Comparing the properties of traditional and novel approaches to the Modified Rankin Scale: systematic review and meta-analysis
Get PDFIntroduction:
The Modified Rankin Scale (mRS) is the most commonly used functional measure in stroke research but is limited by inter-rater reliability (IRR). Various interventions to improve mRS application have been described. We aimed to compare properties of differing approaches to mRS assessment.
Patients and methods:
Multidisciplinary databases (MEDLINE, EMBASE, Health and Psychosocial Instruments [OVID], CINAHL, PsycINFO [EBSCO]) were searched for adult human stroke studies describing psychometric properties of mRS. Two researchers independently screened 20% titles and abstracts, reviewed all full studies, extracted data, and conducted risk of bias (ROB) analysis. Primary outcomes for random-effects meta-analysis were IRR measured by kappa (K) and weighted kappa (KW). Validity and inter-modality reliability measures (Spearman’s rho, KW) were also summarised.
Results:
From 897 titles, 46 studies were eligible, including twelve differing approaches to mRS, 8608 participants. There was high ROB in 14 (30.4%) studies. Overall, reliability was substantial (n = 29 studies, K = 0.65, 95% CI: 0.58–0.71) but IRR was higher for novel approaches to mRS, for example, the Rankin Focussed Assessment (n = 2 studies, K = 0.94, 95% CI: 0.90–0.98) than standard mRS (n = 13 studies, K = 0.55, 95%CI:0.46–0.64). Reliability improved following the introduction of mRS training (K = 0.56, 95% CI: 0.44–0.67; vs K = 0.69, 95% CI: 0.62–0.77). Validity ranged from poor to excellent, with an excellent overall concurrent validity of novel scales (n = 6 studies, KW = 0.86, 95% CI: 0.75–0.97). The agreement between face-to-face and telephone administration was substantial (n = 5 studies, KW = 0.80, 95% CI: 0.74–0.87).
Discussion:
The mRS is a valid measure of function but IRR remains an issue. The present findings are limited by a high ROB and possible publication bias.
Conclusion:
Interventions to improve mRS reliability (training, structured interview, adjudication) seem to be beneficial, but single interventions do not completely remove reliability concerns
Oscillatory brain activity in the canonical alpha-band conceals distinct mechanisms in attention
Get PDFBrain oscillations in the alpha-band (8-14Hz) over posterior areas have been linked to specific processes in attention and perception. In particular, decreases in alpha-amplitude are thought to reflect activation of perceptually relevant brain areas for target engagement, while increases in alpha-amplitude have been associated with inhibition for distractor suppression. Traditionally, these alpha-changes have been viewed as two facets of the same process. However, more recent evidence calls for revisiting this interpretation. Here, we concurrently recorded MEG/EEG in 32 participants (19 females) during covert visuo-spatial attention shifts (spatial cues), and two control conditions (neutral cue, no-attention cue), while tracking fixational eye-movements. In disagreement with a single, perceptually relevant alpha-process, we found the typical alpha-modulations contra- and ipsilateral to the attention focus to be triple dissociated in their timing, topography, and spectral features: Ipsilateral alpha-increases occurred early, over occipital sensors, at a high alpha-frequency (10-14Hz) and were expressed during spatial attention (alpha spatial cue and neutral cue). By contrast, contralateral alpha-decreases occurred later, over parietal sensors, at a lower alpha-frequency (7-10Hz) and were associated with attention deployment in general (alpha spatial and neutral cue and no-attention cue). Additionally, the lateralized early alpha-increases but not -decreases during spatial attention coincided in time with directionally biased microsaccades. Overall, these findings suggest that the attention-related early alpha-increases and late -decreases reflect distinct, likely reflexive versus endogenously controlled attention mechanisms. We conclude that there is more than one perceptually relevant posterior alpha-oscillation, which need to be dissociated for a detailed account of their roles in perception and attention
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