Understanding automated dose control in dynamic X-ray imaging systems

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Osteochondritis dissecans and Osgood Schlatter disease in a family with Stickler syndrome

<p>Abstract</p> <p>Purpose</p> <p>Stickler syndrome is among the most common autosomal dominant connective tissue disorders but is often unrecognised and therefore not diagnosed by clinicians. Despite much speculation, the cause of osteochondrosis in general and osteochondritis dissecans (OCD) and Osgood Schlatter syndrome (OSS) in particular remain unclear. Etiological understanding is essential. We describe a pair of family subjects presented with OCD and OSS as a symptom complex rather than a diagnosis.</p> <p>Methods</p> <p>Detailed clinical and radiographic examinations were undertaken with emphasis on the role of MRI imaging. Magnetic resonance imaging may allow early prediction of articular lesion healing potential in patients with Stickler syndrome.</p> <p>Results</p> <p>The phenotype of Stickler syndrome can be diverse and therefore misleading. The expectation that the full clinical criteria of any given genetic disorder such as Stickler syndrome will always be present can easily lead to an underestimation of these serious inheritable disorders. We report here two family subjects, a male proband and his aunt (paternal sister), both presented with the major features of Stickler syndrome. Tall stature with marfanoid habitus, astigmatism/congenital vitreous abnormality and submucus cleft palate/cleft uvula, and enlarged painful joints with early onset osteoarthritis. Osteochondritis dissecans (OCD) and Osgood Schlatter syndrome (OSS) were the predominating joint abnormalities.</p> <p>Conclusion</p> <p>We observed that the nature of the articular and physeal abnormalities was consistent with a localised manifestation of a more generalised epiphyseal dysplasia affecting the weight-bearing joints. In these two patients, OCD and OSS appeared to be the predominant pathologic musculoskeletal consequences of an underlying Stickler's syndrome. It is empirical to consider generalised epiphyseal dysplasia as a major underlying causation that might drastically affect the weight-bearing joints.</p

Validation study of mHealth technology in HIV to improve empowerment and healthcare utilisation: research and innovation to generate evidence for personalised care (EmERGE)

No description supplie

Positive outcomes: validity, reliability and responsiveness of a novel person-centred outcome measure for people with HIV

Objectives Despite successful treatment, people living with HIV experience persisting and burdensome multidimensional problems. We aimed to assess the validity, reliability and responsiveness of Positive Outcomes, a patient-reported outcome measure for use in clinical practice. Methods In all, 1392 outpatients in five European countries self-completed Positive Outcomes, PAM-13 (patient empowerment), PROQOL-HIV (quality of life) and FRAIL (frailty) at baseline and 12 months. Analysis assessed: (a) validity (structural, convergent and divergent, discriminant); (b) reliability (internal consistency, test-retest); and (c) responsiveness. Results An interpretable four-factor structure was identified: ‘emotional wellbeing’, ‘interpersonal and sexual wellbeing’, ‘socioeconomic wellbeing’ and ‘physical wellbeing’. Moderate to strong convergent validity was found for three subscales of Positive Outcomes and PROQOL (ρ = −0.481 to −0.618, all p < 0.001). Divergent validity was found for total scores with weak ρ (−0.295, p < 0.001). Discriminant validity was confirmed with worse Positive Outcomes score associated with increasing odds of worse FRAIL group (4.81-fold, p < 0.001) and PAM-13 level (2.28-fold, p < 0.001). Internal consistency for total Positive Outcomes and its factors exceeded the conservative α threshold of 0.6. Test-retest reliability was established: those with stable PAM-13 and FRAIL scores also reported median Positive Outcomes change of 0. Improved PROQOL-HIV score baseline to 12 months was associated with improved Positive Outcomes score (r = −0.44, p < 0.001). Conclusions Positive Outcomes face and content validity was previously established, and the remaining validity, reliability and responsiveness properties are now demonstrated. The items within the brief 22-item tool are designed to be actionable by health and social care professionals to facilitate the goal of person-centred care

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

A Dosimetric Quality Audit of Photon Beams By the Belgian-hospital-physicist-association

Since 1987, a dosimetric standardization process has been started by the Belgian Hospital Physicist Association (BHPA). As part of this project, on-site visits were performed by a voluntary team, by request of the local physicist. They included mechanical checks on treatment machines and simulators and a dosimetric intercomparison of photon beams, following the EORTC methodology. Until now 16 centres have participated. Dose measurements were performed in order to evaluate the uniformity in dosimetry after the adoption by the BHPA members of the Nederlandse Commissie voor Stralingsdosimetrie (NCS) code of practice for photon beams [7,9]. Doses were measured with an ionization chamber in water under NCS reference conditions and under other conditions in 13 cobalt beams and 24 high energy X-ray beams from 4 to 25 MV. Under reference conditions, the mean ratio of measured to stated dose is 0.999 (+/- 0.010) and 1.006 (+/- 0.23) for cobalt and X-ray beams, respectively, with a difference between the extreme values (DELTA) of 0.042 for cobalt beams and 0.084 for X-ray beams. In other conditions, the spread is a little larger for all beams. The results are comparable, but with a smaller dispersion, with those of other national and international similar dose intercomparisons and show the importance of applying a common protocol. The results of mechanical checks show some large deviations in digital displays and indicate the need for a systematic mechanical and beam alignment quality assurance programme

Procédé de suralcalinisation d'additifs détergents : rôle des promoteurs et détermination du régime de la réaction de surbasage Overbasing Process of Detergent Additives: Behavior of Promoters and Determination of Factors Controling the Reaction

Le mécanisme du procédé de suralcalinisation des huiles lubrifiantes est étudié. L'analyse du contrôle physique et (ou) chimique est effectué dans ce procédé polyphasique, où une base solide (chaux, magnésie) en suspension dans une solution, constituée d'une microémulsion, est carbonatée. Le carbonate non colloïdal est formé dans le milieu par une réaction successive à celle de la formation de carbonate colloïdal. La réaction, en présence (et en absence) de détergent alkylarylsulfonique, n'est pas limitée par la cinétique chimique, mais par la diffusion des réactifs. Le méthanol, utilisé comme cotensioactif, influe sur la quantité de carbonate colloïdal sans augmenter la vitesse de surbasage. Les essais en milieu anhydre montrent que la présence d'une quantité très faible d'eau est indispensable. L'importance de la dilution par le solvant (xylène) et la réactivité comparée MgO/Ca(OH)2 sont discutées. <br> Overbased (overalcalinized) detergent additives are applied in lubrication of modern combustion engines : they neutralize the acidic products coming from combustion and fight corrosive wear. Overbased calcium sulfonates, the most widely used are made by carbonating CaO or Ca(OH)2 in an hydrocarbon mixture (alkane + xylene) containing a detergent (mostly alkylaryl-sulfonate) and reaction promoters (water, alcohol, amine). The process is operated by several companies and a large amount of patent literature is reported on the subject [2]; however if the geometrical and physical nature of the colloidal carbonare particles formed in the process has been studied, very little is known on the fundamental aspects and on the mechanism of the overbasing process; this is what is described and discussed in this paper. Following previous kinetic results on experimental parameters associated to carbonatation, [4], further data are obtained applying kinetic graphs used in reactor analysis of complex reactions (Fig. 1). Plotting YA/B (colloidal carbonate/initial Ca(OH)2) versus P (yield of non colloïdal carbonate) shows clearly (Fig. 2) that the non-colloidal CaCO3, eliminated by contrifugation at several extends of the reaction progress, comes from a consecutive and not from a parallel reaction. A pseudoternary, phase diagram of (detergent + oil; water; MeOH) indicates a very narrow monophasic area (Fig. 3) which implies the need of small amounts of water. The assignement of the chemical or physical nature of the reaction is made from the equations related to the chemical engineering model of the shrinking spherical particle (Fig. 5). The results show clearly that the overbasing process is under diffusion control (Fig. 9), and that the chemical reaction is not the determining factor. A detailed analysis of the process is made by varying the chemical parameters involved. A minimum amount of methanol is necessary for the carbonatation to give a significant value of TBN (total base number) but an excess of methanol makes the final product not fluid enough and even solid. There is a linear relation between the volume of methanol and the volume (TBN 2/3) of micellar carbonate (Fig. 11). However the maximum of TBN is independant of the amount of methanol. This is consistent with a multiparametric role of MeOH involved in wettingthe colloids and in changing the physical nature of the micelles [8-10]. A minimum amount of water is also necessary, in agreement with recent observations on the mechanism of solid-liquid Phase Transfer Catalysis [11]. Increasing the amount of xylene increases the rate of carbonatation, probably by reducing the viscosity of the reaction medium, without changing the final value of TBN. In addition, there is a large difference of carbonatation rate when comparing MgO and Ca(OH)2. In summary the results of this study show that diffusion is determinant in the reaction. The promoters are necessary and play a multiparametric role. The mass transfer of Ca(OH)2 does not occur through formation of organosoluble species as in the alcoholate process [2]. The overbasing mechanism is in agreement with the dynamic behavior [13-16] and the theorical concepts [17-18] of micellar systems