Hydrodynamical simulations of a cloud of interacting gas fragments

We present a full hydrodynamical investigation of a system of self-contained, interacting gas `cloudlets'. Calculations are performed using SPH, and cloudlets are allowed to collide, dissipate kinetic energy, merge and undergo local gravitational collapse. The numerical feasibility of such a technique is explored, and the resolution requirements examined. We examine the effect of the collision time and the velocity field on the timescale for evolution of the system, and show that almost all star formation will be confined to dense regions much smaller than the entire cloud. We also investigate the possibility, discussed by various authors, that such a system could lead to a power-law IMF by a process of repeated cloudlet coagulation, finding that in fact the inter-cloudlet collisions occur at too high a Mach number for merging to play an important part.Comment: 11 pages, 12 figures. Accepted for publication in MNRAS. Animations of calculations are available, contact D. Gittins if intereste

Cerebral and tumoral blood flow in adult gliomas: a systematic review of results from magnetic resonance imaging

OBJECTIVE: Blood flow is the rate of blood movement and relevant to numerous processes, though understudied in gliomas. The aim of this review was to pool blood flow metrics obtained from MRI modalities in adult supratentorial gliomas. METHODS: MEDLINE, EMBASE and the Cochrane database were queried 01/01/2000–31/12/2019. Studies measuring blood flow in adult Grade II–IV supratentorial gliomas using dynamic susceptibility contrast (DSC) MRI, dynamic contrast enhanced MRI (DCE-MRI) or arterial spin labelling (ASL) were included. Absolute and relative cerebral blood flow (CBF), peritumoral blood flow and tumoral blood flow (TBF) were reported. RESULTS: 34 studies were included with 1415 patients and 1460 scans. The mean age was 52.4 ± 7.3 years. Most patients had glioblastoma (n = 880, 64.6%). The most common imaging modality was ASL (n = 765, 52.4%) followed by DSC (n = 538, 36.8%). Most studies were performed pre-operatively (n = 1268, 86.8%). With increasing glioma grade (II vs IV), TBF increased (70.8 vs 145.5 ml/100 g/min, p < 0.001) and CBF decreased (85.3 vs 49.6 ml/100 g/min, p < 0.001). In Grade IV gliomas, following treatment, CBF increased in ipsilateral (24.9 ± 1.2 vs 26.1 ± 0.0 ml/100 g/min, p < 0.001) and contralateral white matter (25.6 ± 0.2 vs 26.0± 0.0 ml/100 g/min, p < 0.001). CONCLUSION: Our findings demonstrate that increased mass effect from high-grade gliomas impairs blood flow within the surrounding brain that can improve with surgery. ADVANCES IN KNOWLEDGE: This systematic review demonstrates how mass effect from brain tumours impairs blood flow in the surrounding brain parenchyma that can improve with treatment

Patients' reports or clinicians' assessments: Which are better for prognosticating?

BACKGROUND: The Prognosis in Palliative care Scale (PiPS) predicts survival in advanced cancer patients more accurately than a doctor's or a nurse's estimate. PiPS scores are derived using observer ratings of symptom severity and performance status. The purpose of this study was to determine whether patient-rated data would provide better prognostic estimates than clinician observer ratings. PATIENTS AND METHODS: 1018 subjects with advanced cancer no longer undergoing tumour-directed therapy were recruited to a multi-centre study. Prognostic models were developed using observer ratings, patient ratings or a composite method that used patient ratings when available or else used observer ratings. The performance of the prognostic models was compared by determining the agreement between the models' predictions and the survival of study participants. RESULTS: All three approaches to model development resulted in prognostic scores that were able to differentiate between patients with a survival of 'days', 'weeks' or 'months+'. However, the observer-rated models were significantly (p<0.05) more accurate than the patient-rated models. CONCLUSIONS: A prognostic model derived using observer-rated data was more accurate at predicting survival than a similar model derived using patient self-report measures. This is clinically important because patient-rated data can be burdensome and difficult to obtain in patients with terminal illnesses

Trajectories of distress and recovery, secondary stressors and social cure processes in people who used the resilience hub after the Manchester Arena bombing

Background: Terrorist incidents lead to a range of mental health outcomes for people affected, sometimes extending years after the event. Secondary stressors can exacerbate them, and social support can provide mitigation and aid recovery. There is a need to better understand distress and mitigating factors among survivors of the Manchester Arena attack in 2017. Aims: We explored three questions. First, what experiences of distress did participants report? Second, how might secondary stressors have influenced participants' psychosocial recoveries? Third, what part has social support played in the relationships between distress and participants' recovery trajectories? Method We conducted a cross-sectional online survey of a convenience sample of survivors of the Manchester Arena bombing (N = 84) in January 2021 (3 years 8 months post-incident), and a longitudinal study of the same participants' scores on mental health measures over 3 years from September 2017. Results: Survivors' mental well-being scores in early 2021 were significantly lower than general population norms. Longitudinal follow-up provided evidence of enduring distress. Secondary stressors, specifically disruptions to close relationships, were associated with greater post-event distress and slower recovery. We found an indirect relationship between identifying with, and receiving support from, others present at the event and mental well-being >3 years later. Conclusions: The Arena attack has had an enduring impact on mental health, even in survivors who had a mild response to the event. The quality of close relationships is pivotal to long-term outcome. Constructive support from family and friends, and people with shared experiences, are key to social cure processes that facilitate coping and recovery

Delivery, dose, outcomes and resource use of stroke therapy: the SSNAPIEST observational study

BackgroundTherapy is key to effective stroke care, but many patients receive little.ObjectivesTo understand how stroke therapy is delivered in England, Wales and Northern Ireland, and which factors are associated with dose, outcome and resource use.DesignSecondary analysis of the Sentinel Stroke National Audit Programme, using standard descriptive statistics and multilevel mixed-effects regression models, while adjusting for all known and measured confounders.SettingStroke services in England, Wales and Northern Ireland.ParticipantsA total of 94,905 adults admitted with stroke, who remained an inpatient for > 72 hours.ResultsRoutes through stroke services were highly varied (> 800), but four common stroke pathways emerged. Seven distinct impairment-based patient subgroups were characterised. The average amount of therapy was very low. Modifiable factors associated with the average amount of inpatient therapy were type of stroke team, timely therapy assessments, staffing levels and model of therapy provision. More (of any type of) therapy was associated with shorter length of stay, less resource use and lower mortality. More occupational therapy, speech therapy and psychology were also associated with less disability and institutionalisation. Large amounts of physiotherapy were associated with greater disability and institutionalisation.LimitationsUse of observational data does not infer causation. All efforts were made to adjust for all known and measured confounding factors but some may remain. We categorised participants using the National Institutes of Health Stroke Scale, which measures a limited number of impairments relatively crudely, so mild or rare impairments may have been missed.ConclusionsStroke patients receive very little therapy. Modifiable organisational factors associated with greater amounts of therapy were identified, and positive associations between amount of therapy and outcome were confirmed. The reason for the unexpected associations between large amounts of physiotherapy, disability and institutionalisation is unknown. Prospective work is urgently needed to investigate further. Future work needs to investigate (1) prospectively, the association between physiotherapy and outcome; (2) the optimal amount of therapy to provide for different patient groups; (3) the most effective way of organising stroke therapy/rehabilitation services, including service configuration, staffing levels and working hours; and (4) how to reduce unexplained variation in resource use.FundingThis project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 17. See the NIHR Journals Library website for further project information

How do patients pass through stroke services? Identifying stroke care pathways using national audit data.

OBJECTIVE: To map and describe how patients pass through stroke services. METHODS: Data from 94,905 stroke patients (July 2013-July 2015) who were still inpatients 72 hours after hospital admission were extracted from a national stroke register and were used to identify the routes patients took through hospital and community stroke services. We sought to categorize these routes through iterative consultations with clinical experts and to describe patient characteristics, therapy provision, outcomes and costs within each category. RESULTS: We identified 874 routes defined by the type of admitting stroke team and subsequent transfer history. We consolidated these into nine distinct routes and further summarized these into three overlapping 'pathways' that accounted for 99% of the patients. These were direct discharge (44%), community rehabilitation (47%) and inpatient transfer (19%) with 12% of the patients receiving both inpatient transfer and community rehabilitation. Patients with the mildest and most severe strokes were more likely to follow the direct discharge pathway. Those perceived to need most therapy were more likely to follow the inpatient transfer pathway. Costs were lowest and mortality was highest for patients on the direct discharge pathway. Outcomes were best for patients on the community rehabilitation pathway and costs were highest where patients underwent inpatient transfers. CONCLUSION: Three overarching stroke care pathways were identified which differ according to patient characteristics, therapy needs and outcomes. This pathway mapping provides a benchmark to develop and plan clinical services, and for future research

The promoter from SlREO, a highly-expressed, root-specific Solanum lycopersicum gene, directs expression to cortex of mature roots

Root-specific promoters are valuable tools for targeting transgene expression, but many of those already described have limitations to their general applicability. We present the expression characteristics of SlREO, a novel gene isolated from tomato (Solanum lycopersicum L.). This gene was highly expressed in roots but had a very low level of expression in aerial plant organs. A 2.4-kb region representing the SlREO promoter sequence was cloned upstream of the uidA GUS reporter gene and shown to direct expression in the root cortex. In mature, glasshouse-grown plants this strict root specificity was maintained. Furthermore, promoter activity was unaffected by dehydration or wounding stress but was somewhat suppressed by exposure to NaCl, salicylic acid and jasmonic acid. The predicted protein sequence of SlREO contains a domain found in enzymes of the 2-oxoglutarate and Fe(II)-dependent dioxygenase superfamily. The novel SlREO promoter has properties ideal for applications requiring strong and specific gene expression in the bulk of tomato root tissue growing in soil, and is also likely to be useful in other Solanaceous crop