Digital x-ray analysis for monitoring fracture healing

X-ray based evaluation of different stages of fracture healing is a well established clinical standard. However, several studies have shown plain radiography alone to be an unreliable method to assess healing. The advent of digital X-ray systems provides the potential to perform quantitative analysis on X-ray images without disrupting normal clinical practice. Two aspects were explored in this study. The first was the measurement of mechanical fracture stiffness under four point bending and axial loading. The second was the inclusion of an Aluminium step wedge to provide Aluminium-equivalent thickness calibration information. Mechanical sti ness studies involved the development of equipment to perform four point bending on intra-medullary (IM) nailed tibial fractures, equipment to perform axial loading on conservatively treated humeral fractures, and fracture models to ex- amine the developed systems. Computational procedures to automatically measure the angle and offset occurring at the fracture site by comparing loaded and unloaded X-ray images were developed utilising cross-correlation. The apparatus and procedures were tested using the fracture models both in X-ray and using the Zwick materials testing machine. The four point bending system was applied clinically to a series of IM nailed tibial fracture patients and the axial loading system to two conservatively treated humeral fracture patients. Mechanical stiffness results showed that the apparatus worked well in the clinical radiography environment and was unobtrusive to normal practice. The developed X-ray analysis procedure provided reliable measurements. However, in the case of IM nailed tibial fractures, both angular and displacement movements were too small to be accurately assessed or to provide reliable stiffness measurements. This indicated that this patient group was possibly unsuitable for mechanical stiffness measurements or that higher loads needed to be applied to the fracture site. The case studies of conservatively treated humeral fractures showed potential in detecting movement between loaded and unloaded X-rays and using this to provide sti ness information. Further investigation is required to show that this technique has the potential to aid fracture healing monitoring. Investigation into Aluminium step wedge calibration began with the design of different step wedges and X-ray phantoms. Initial image analysis involved studying the automatic processing applied by a digital Computed Radiography (CR) Fuji sys- tem and modelling of the inhomogeneities in X-ray images as well as investigation into the effect of and correction for scatter, overlying soft tissue and bone thickness. Computational procedures were developed to semi-automatically detect the steps of the step wedge, form an exponential Aluminium step thickness to grey level calibration graph, measure soft tissue and bone thickness, and correct for the heel effect and scatter contributions. Tests were carried out on pre-clinical models and results compared to ash weight and peripheral quantitative computed tomography (pQCT). A clinical study of radial fractures was used to investigate the effectiveness of the step wedge calibration system in monitoring fracture healing changes. Results using the step wedge indicated that the calibration technique was e ective in detecting and correcting for aspects in uencing Aluminium-equivalent thickness measures. With careful processing, useful information was obtained from digital X- rays that included the Aluminium step wedge and these correlated well with existing density measures. The use of the wedge in patient images showed that small increases in Aluminium-equivalent thickness of the fracture site could be detected. This was most useful for intra-patient comparisons throughout the course of healing rather than providing quantitative measurements which were comparable to other density measures. In conclusion, this thesis shows the potential for accurate analysis of digital X- rays to aid the monitoring of healing changes in fracture patients, particularly with application of axial loading and the use of step wedge calibration

Quantifying extreme behaviour in geomagnetic activity

Understanding the extremes in geomagnetic activity is an important component in understanding just how severe conditions can become in the terrestrial space environment. Extreme activity also has consequences for technological systems. On the ground, extreme geomagnetic behavior has an impact on navigation and position accuracy and the operation of power grids and pipeline networks. We therefore use a number of decades of one-minute mean magnetic data from magnetic observatories in Europe, together with the technique of extreme value statistics, to provide a preliminary exploration of the extremes in magnetic field variations and their one-minute rates of change. These extremes are expressed in terms of the variations that might be observed every 100 and 200 years in the horizontal strength and in the declination of the field. We find that both measured and extrapolated extreme values generally increase with geomagnetic latitude (as might be expected), though there is a marked maximum in estimated extreme levels between about 53 and 62 degrees north. At typical midlatitude European observatories (55–60 degrees geomagnetic latitude), compass variations may reach approximately 3–8 degrees/minute, and horizontal field changes may reach 1000–4000 nT/minute, in one magnetic storm once every 100 years. For storm return periods of 200 years the equivalent figures are 4–11 degrees/minute and 1000–6000 nT/minute

Mental health among healthcare workers and other vulnerable groups during the COVID-19 pandemic and other coronavirus outbreaks: A rapid systematic review.

INTRODUCTION: Although most countries and healthcare systems worldwide have been affected by the COVID-19 pandemic, some groups of the population may be more vulnerable to detrimental effects of the pandemic on mental health than others. The aim of this systematic review was to synthesise evidence currently available from systematic reviews on the impact of COVID-19 and other coronavirus outbreaks on mental health for groups of the population thought to be at increased risk of detrimental mental health impacts. MATERIALS AND METHODS: We conducted a systematic review of reviews on adults and children residing in a country affected by a coronavirus outbreak and belonging to a group considered to be at risk of experiencing mental health inequalities. Data were collected on symptoms or diagnoses of any mental health condition, quality of life, suicide or attempted suicide. The protocol for this systematic review was registered in the online PROSPERO database prior to commencing the review (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=194264). RESULTS: We included 25 systematic reviews. Most reviews included primary studies of hospital workers from multiple countries. Reviews reported variable estimates for the burden of symptoms of mental health problems among acute healthcare workers, COVID-19 patients with physical comorbidities, and children and adolescents. No evaluations of interventions were identified. Risk- and protective factors, mostly for healthcare workers, showed the importance of personal factors, the work environment, and social networks for mental health. CONCLUSIONS: This review of reviews based on primary studies conducted in the early months of the COVID-19 pandemic shows a lack of evidence on mental health interventions and mental health impacts on vulnerable groups in the population

MGMT promoter methylation testing to predict overall survival in people with glioblastoma treated with temozolomide:a comprehensive meta-analysis based on a Cochrane Review

BACKGROUND: The DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) causes resistance of tumor cells to alkylating agents. It is a predictive biomarker in high-grade gliomas treated with temozolomide, however, there is no consensus on which test method, methylation sites, and cutoff values to use. METHODS: We performed a Cochrane Review to examine studies using different techniques to measure MGMT and predict survival in glioblastoma patients treated with temozolomide. Eligible longitudinal studies included (i) adults with glioblastoma treated with temozolomide with or without radiotherapy, or surgery; (ii) where MGMT status was determined in tumor tissue, and assessed by 1 or more technique; and (iii) where overall survival was an outcome parameter, with sufficient information to estimate hazard ratios (HRs). Two or more methods were compared in 32 independent cohorts with 3474 patients. RESULTS: Methylation-specific PCR (MSP) and pyrosequencing (PSQ) techniques were more prognostic than immunohistochemistry for MGMT protein, and PSQ is a slightly better predictor than MSP. CONCLUSIONS: We cannot draw strong conclusions about use of frozen tissue vs formalin-fixed paraffin-embedded in MSP and PSQ. Also, our meta-analysis does not provide strong evidence about the best CpG sites or threshold. MSP has been studied mainly for CpG sites 76-80 and 84-87 and PSQ at CpG sites ranging from 72 to 95. A cutoff threshold of 9% for CpG sites 74-78 performed better than higher thresholds of 28% or 29% in 2 of the 3 good-quality studies. About 190 studies were identified presenting HRs from survival analysis in patients in which MGMT methylation was measured by 1 technique only

Predicting Shielding Effectiveness of Populated Enclosures Using Absorption Cross Section of PCBs

Shielding effectiveness (SE) is an important measure of how well an enclosure reduces the electromagnetic (EM) field incident upon it. Commonly, when the shielding effectiveness of an enclosure is stated it is for the case when the enclosure is empty. Including contents such as printed circuit boards (PCBs) in the enclosure will affect the shielding effectiveness as the PCB absorbs EM energy. One technique of determining how much energy a PCB absorbs is to measure its absorption cross section (ACS) using a reverberation chamber (RC). The measured ACS can be used to predict the shielding effectiveness of an enclosure when the PCB is inside it using power balance techniques. In this paper the ACS of a number of PCBs are measured both individually and in closely stacked groups. This information is then used to show how the ACS can be used to calculate shielding effectiveness and the results are compared to direct measurement of the SE of the enclosure containing a PCB. Knowledge of the ACS of typical or particular PCBs could be used by engineers to estimate the real shielding effectiveness of an enclosure with contents, when designing electronic systems

Safe and just operating spaces for regional social-ecological systems

Humanity faces a major global challenge in achieving wellbeing for all, while simultaneously ensuring that the biophysical processes and ecosystem services that underpin wellbeing are exploited within scientifically informed boundaries of sustainability. We propose a framework for defining the safe and just operating space for humanity that integrates social wellbeing into the original planetary boundaries concept (Rockström et al., 2009a,b) for application at regional scales. We argue that such a framework can: (1) increase the policy impact of the boundaries concept as most governance takes place at the regional rather than planetary scale; (2) contribute to the understanding and dissemination of complexity thinking throughout governance and policy-making; (3) act as a powerful metaphor and communication tool for regional equity and sustainability. We demonstrate the approach in two rural Chinese localities where we define the safe and just operating space that lies between an environmental ceiling and a social foundation from analysis of time series drawn from monitored and palaeoecological data, and from social survey statistics respectively. Agricultural intensification has led to poverty reduction, though not eradicated it, but at the expense of environmental degradation. Currently, the environmental ceiling is exceeded for degraded water quality at both localities even though the least well-met social standards are for available piped water and sanitation. The conjunction of these social needs and environmental constraints around the issue of water access and quality illustrates the broader value of the safe and just operating space approach for sustainable development

Lack of Evidence for Ribavirin Treatment of Lassa Fever in Systematic Review of Published and Unpublished Studies

Ribavirin has been used widely to treat Lassa fever in West Africa since the 1980s. However, few studies have systematically appraised the evidence for its use. We conducted a systematic review of published and unpublished literature retrieved from electronic databases and gray literature from inception to March 8, 2022. We identified 13 studies of the comparative effectiveness of ribavirin versus no ribavirin treatment on mortality outcomes, including unpublished data from a study in Sierra Leone provided through a US Freedom of Information Act request. Although ribavirin was associated with decreased mortality rates, results of these studies were at critical or serious risk for bias when appraised using the ROBINS-I tool. Important risks for bias related to lack of control for confounders, immortal time bias, and missing outcome data. Robust evidence supporting the use of ribavirin in Lassa fever is lacking. Well-conducted clinical trials to elucidate the effectiveness of ribavirin for Lassa fever are needed