Feasibility study of computational occupational dosimetry: evaluating a proof-of-concept in an endovascular and interventional cardiology setting.

Individual monitoring of radiation workers is essential to ensure compliance with legal dose limits and to ensure that doses are As Low As Reasonably Achievable. However, large uncertainties still exist in personal dosimetry and there are issues with compliance and incorrect wearing of dosimeters. The objective of the PODIUM (Personal Online Dosimetry Using Computational Methods) project was to improve personal dosimetry by an innovative approach: the development of an online dosimetry application based on computer simulations without the use of physical dosimeters. Occupational doses were calculated based on the use of camera tracking devices, flexible individualised phantoms and data from the radiation source. When combined with fast Monte Carlo simulation codes, the aim was to perform personal dosimetry in real-time. A key component of the PODIUM project was to assess and validate the methodology in interventional radiology workplaces where improvements in dosimetry are needed. This paper describes the feasibility of implementing the PODIUM approach in a clinical setting. Validation was carried out using dosimeters worn by Vascular Surgeons and Interventional Cardiologists during patient procedures at a hospital in Ireland. Our preliminary results from this feasibility study show acceptable differences of the order of 40% between calculated and measured staff doses, in terms of the personal dose equivalent quantity Hp(10), however there is a greater deviation for more complex cases and improvements are needed. The challenges of using the system in busy interventional rooms have informed the future needs and applicability of PODIUM. The availability of an online personal dosimetry application has the potential to overcome problems that arise from the use of current dosimeters. In addition, it should increase awareness of radiation protection among staff. Some limitations remain and a second phase of development would be required to bring the PODIUM method into operation in a hospital setting. However, an early prototype system has been tested in a clinical setting and the results from this two-year proof-of-concept PODIUM project are very promising for future development.

Virtual estimation of effective dose in neutron fields.

The PODIUM project aims to provide real-time assessments of occupationally exposed workers by tracking their motion and combining this with a simulation of the radiation field. The present work describes the approach that would be taken in mixed neutron-gamma fields, and details the methods for generating and applying an effective dose rate map; the required fluence to effective dose conversion coefficients at intercardinal angles are also presented. A proof-of-concept of the approach is demonstrated using a simple simulated workplace field within a calibration laboratory, with corroborative comparisons made against survey instrument measurements generally confirming good agreement. Simulated tracking of an individual within the facility was performed, recording a 1.25µSv total effective dose and accounting for dose rates as low as 0.5 nSv h-1, which is much lower than anything that could be accurately measured by physical neutron dosemeters in such a field.

Regulation of the sonography profession and patient safety: A comparative study between Australia and New Zealand with implications for statutory regulation.

INTRODUCTION: The primary aim of statutory regulation in healthcare is patient safety. Few studies examine health professionals' perceptions of statutory regulation and its impact on patient safety. Statutory regulation of sonographers is different in Australia and New Zealand which affords a unique opportunity to compare and contrast regulation and its impact. METHODS: An interpretive policy analysis investigated how statutory regulation in the sonography profession addresses patient safety in Australia and New Zealand. A framework analysis explored relevant statutory regulatory policy as well as interviews from sonographers. RESULTS: Four policy documents were included. Thirty-one sonographers in Australia and nine in New Zealand took part in semi-structured interviews. Four themes described statutory regulation and its impact on patient safety: how statutory regulation is implemented in practice to address patient safety; factors contributing to implementation of statutory regulation; impact of statutory regulation on sonographers; and considerations for regulation. CONCLUSION: Statutory regulation provides a reference point for safe practice but can be non-specific in defining sonographers' roles and outlining strategies that address patient safety. Sonographers' perspectives of how regulation of practice addresses patient safety was mixed. A gap exists in sonographers' understanding of the role of statutory regulation in patient safety. IMPLICATIONS FOR PRACTICE: Regulatory authorities must consider how to effectively engage and educate both patients and practitioners about their role in patient safety. Practitioners should also take the opportunity to engage in understanding the role of statutory regulation in enhancing patient safety. A broader view of how Fitness-to-Practice in sonography is managed should be considered in light of the findings.

Ambient light intensity affecting ultrasound operator detection of liver lesions in cine-clips.

INTRODUCTION: Ambient light (AL) is an important factor to improve ultrasound pathology detection. However, there are no established room AL levels recommended during an ultrasound examination. We aim to examine the diagnostic accuracy using different intensity of AL for the detection of liver lesions in anonymised pre-recorded cine-clips. METHODS: Eight ultrasound operators with 5-14 years' professional experiences were prospectively recruited to evaluate 51 randomised cine-clips directly from one ultrasound machine. These 15-s clips of the right lobe of the liver in longitudinal and transverse planes were meant to simulate the ultrasound examination. Operators reviewed all cine-clips and responded to two questions per cine-clip regarding their detection performance under 3 AL settings; 3, 15 and 25 lux, at one lighting per visit. A repeat visit under each AL was performed to assess for intra-operator variability. Each operator completed six visits in total, with at least a 2-day washout period. The operators' performance was compared against imaging reference standards from contrast CT/MRI for cine-clips with lesion and serial US for those without. RESULTS: AL with highest degree of diagnostic accuracy was found to be at 25 lux. Results from 8 operators revealed sensitivity ranged from 79% to 100%, specificity ranged from 94% to 100%. Positive and negative predictive values were up to 100% with AL at 25 lux. Both intra-and interrater reliability were excellent at 0.85-1.0 (0.79-0.98) and 0.98 (0.97, 0.99) respectively, with AL at 25 lux. CONCLUSION: This study proved that ambient light intensity affects the ultrasound operator detection of liver lesions on cine-clips. IMPLICATIONS FOR PRACTICE: Identifying suitable AL levels will influence future ultrasound room construct.

The bearing capacity of asteroid (65803) Didymos estimated from boulder tracks.

The bearing capacity - the ability of a surface to support applied loads - is an important parameter for understanding and predicting the response of a surface. Previous work has inferred the bearing capacity and trafficability of specific regions of the Moon using orbital imagery and measurements of the boulder tracks visible on its surface. Here, we estimate the bearing capacity of the surface of an asteroid for the first time using DART/DRACO images of suspected boulder tracks on the surface of asteroid (65803) Didymos. Given the extremely low surface gravity environment, special attention is paid to the underlying assumptions of the geotechnical approach. The detailed analysis of the boulder tracks indicates that the boulders move from high to low gravitational potential, and provides constraints on whether the boulders may have ended their surface motion by entering a ballistic phase. From the 9 tracks identified with sufficient resolution to estimate their dimensions, we find an average boulder track width and length of 8.9 ± 1.5 m and 51.6 ± 13.3 m, respectively. From the track widths, the mean bearing capacity of Didymos is estimated to be 70 N/m2, implying that every 1 m2 of Didymos' surface at the track location can support only ~70 N of force before experiencing general shear failure. This value is at least 3 orders of magnitude less than the bearing capacity of dry sand on Earth, or lunar regolith.

Treatment of wastewater phosphate by reductive dissolution of iron: use of ferric oxyhydroxide media.

In smaller wastewater treatment systems such as septic systems, there is an interest in the development of passive phosphorus (P) removal methods. This study tested fixed-bed filters containing ferric oxyhydroxide media for wastewater P removal in a laboratory column test and in a full-scale domestic septic system. In the column test, during 30 mo of dosing with domestic wastewater, reductive iron dissolution reactions delivered consistent moderate concentrations of Fe into solution (2.9 ± 1.6 mg L), and influent PO-P of 3.7 ± 1.0 mg L was attenuated to 0.09 + 0.04 mg L in the column effluent (98% removal). Phosphorus breakthrough at successive locations along the column indicated that in addition to sorption, mineral precipitation reactions probably also played an important role in the observed P attenuation. This was supported by electron microprobe analyses, which showed the presence of thick (20 µm) secondary Fe-rich coatings containing P on the primary ferric media grains. Assays of NaHCO-leachable and acid-extractable P on the column solids showed accumulation of up to 5.4 mg g acid-extractable P near the column inlet, but <5% of this amount was easily desorbable, further indicating P attenuation from processes other than sorption. Over 19 mo of operation, the domestic septic system also showed generally consistent increased Fe in the filter effluent (2.6 ± 1.7 mg L) and achieved 99% P removal to 0.03 ± 0.02 mg L when the effluent was subsequently oxidized in a sand filter. Ferric iron filters could be attractive options for P removal in smaller wastewater systems because of their passive nature.

Regulation of healthcare and medical imaging in Australia: A narrative review of the evolution, function and impact on professional behaviours.

OBJECTIVES: This review explores the literature about the status and influence of statutory regulation in healthcare with a focus on medical imaging. It summarises the status of regulation in Australia for radiographers and sonographers, with brief reference to the global situation. The role of regulation is explored in terms of its evolution, function and effect on professional behaviours. KEY FINDINGS: Reports of medical errors, sentinel events and professional misconduct in healthcare have raised concern about how health care professionals are regulated. Patient-centric healthcare delivery has changed how people interact with healthcare, contributing to the development of statutory regulation for many healthcare professions. In Australia, the Health Practitioner Regulation National Law (The National Law) 2009, established the National Registration and Accreditation Scheme (NRAS) in order to practice. Not all health care professions are included in the scheme. In medical imaging, radiographers are included but sonographers are a notable exception. Regulation is designed to positively influence practitioners' professional behaviours. The available evidence however is limited, but suggests that under certain circumstances, it can negatively impact practitioners' professional behaviours. CONCLUSION: Statutory regulation has been implemented to address serious issues highlighted in reports of medical errors and professional misconduct, but it may have unintended consequences on the professional behaviours of practitioners. Limited research means the relationship between statutory regulation of healthcare practitioners and its impact upon professional behaviours remains unclear. IMPLICATIONS FOR PRACTICE: If statutory regulation of healthcare professionals is to achieve its aim of protecting the public, it is imperative that we understand the impact that it has on professional behaviours. This review highlights that it can negatively impact professional behaviours which may be detrimental to patient's safety.

CeFePO: f-d hybridization and quenching of superconductivity.

As a homologue to the new, Fe-based type of high-temperature superconductors, the electronic structure of the heavy-fermion compound CeFePO was studied by means of angle-resolved resonant photoemission. It was experimentally found-and later on confirmed by local-density approximation (LDA) as well as dynamical mean-field theory (DMFT) calculations-that the Ce 4f states hybridize to the Fe 3d states of d{3z{2}-r{2}} symmetry near the Fermi level that discloses their participation in the occurring electron-correlation phenomena and provides insight into mechanism of superconductivity in oxopnictides.

Ustekinumab treatment for moderate-to-severe plaque psoriasis: eight-year real-life experience.

Background: Limited information is available from real-life studies evaluating the long-term efficacy and drug retention of ustekinumab.Research design and methods: Data from 378 patients with moderate-severe psoriasis were retrospectively analyzed. Over 8 years, disease severity and treatment response were evaluated using the PASI score. Predictors of PASI response were evaluated by logistic regression. Ustekinumab retention rate was calculated by the Kaplan-Meier method.Results: Over the 8 years, >80% of patients achieved a PASI score of <3 and PASI 75, 90 and 100 response was achieved in 76.2%, 61.9% and 57.1% of patients, respectively. Predictor variables for improved PASI response (after 2 years) were HLA-C*06-POS patients, female gender and BMI <30 Kg/M2. The 2-year retention rate was 81% and 59% after 8 years with mean retention rate of 5.4 years. Improved retention rate was observed in patients positive for the HLA-C*06 allele (3.7 vs. 2.5 years, p = 0.005) and female gender (3.7 vs. 3.3 years, p = 0.06), with no significant difference observed in other patient groups. Ustekinumab was generally well tolerated without evidence of cumulative toxicity or organ toxicity.Conclusion: The long-term use of ustekinumab was observed to be effective and safe in patients with moderate-severe chronic psoriasis in a real world-setting.

The safety of anti-interleukins monoclonal antibodies for the treatment of psoriasis.

Introduction: Psoriasis is a chronic inflammatory disease and affects about 10% of the world's population. Psoriasis is associated with a number of comorbidities. Biologic therapies for the treatment of moderate-severe plaque psoriasis include tumor necrosis factor α inhibitors (TNFi), and newer molecules targeting IL-12 and 23, blocking p40 subunit, or targeting subunit p19 of IL-23 and other molecules blocking IL-17A, or directed against the IL-17 receptor. Areas covered: Anti-interleukin drugs show great improvement in disease control and on the other hand are not affected by important adverse reactions of older compounds. Approach to chronic disease affected patients, in particular, and to patients with multiple comorbidities is revolutionized by novel molecules that are safer and more manageable. Expert opinion: A recent work suggests that pro-fibrogenic cytokines, IL-17, might be important player of liver damage and even in regulation of obesity, diabetes, and non-alcoholic fatty liver disease (NAFLD) pathogenesis. Choosing to interfere with IL-23/Il-17 axis, definitely, is like acting against psoriatic march and in a parallel way against its comorbidities.

Pharmacotherapeutic management of psoriasis in adolescents and children.

Introduction: Psoriasis is a relatively common condition, with a lot of discordance in studies about the peak of onset. In a large German study, an almost linear prevalence increase was reported during childhood, ranging from 0.12% at 1 year to 1-2% at 18 years. According to recent studies, plaque psoriasis is the most common variant in childhood disease. Areas covered: This article focuses on topical, systemic and biologic therapies used in childhood psoriasis. The authors performed a full literature PubMed research, while incorporating case reports and experience. Topical agents are considered the first step, but they always have little efficacy in the extensive form of the disease. In this case, systemic and particularly biological therapy must be evaluated. The most studied treatment in the pediatric population is etanercept, but adalimumab and ustekinumab are also approved in pediatric and adolescent populations. Expert opinion: Larger studies are needed to further investigate the use of new compounds in childhood psoriasis. Recent evidence suggests that practitioners should consider interceding in the early immunologic psoriatic process to halt this march and stunt immunological scar development. An early investment would provide lasting effects and serious impact in long-term disease modification.

Noradrenaline modulates neuronal responses to GABA in vestibular nuclei.

The effects of noradrenaline (NA) on the inhibitory responses to GABA were studied in vivo in neurons of the vestibular nuclei of the rat using extracellular recordings of single unit electrical activity and a microiontophoretic technique of drug application in loco. NA application influenced GABA-evoked inhibitions in 82% of tested neurons, depressing them in 42% and enhancing them in 40% of cases. The more frequent action of NA on GABA responses was depressive in lateral and superior vestibular nuclei (50% of neurons) and enhancing in the remaining nuclei (56% of neurons). The most intense effect of NA application was the enhancement of GABA responses induced in a population of lateral vestibular nucleus neurons, characterized by a background firing rate significantly higher than that of other units. The alpha(2) noradrenergic receptor agonist clonidine mimicked the enhancing action of NA on GABA responses; this action was blocked by application of the specific alpha(2) antagonist yohimbine. The beta adrenergic agonist isoproterenol induced either depressive or enhancing effects on GABA responses; the former more than the latter were totally or partially blocked by application of the beta antagonist timolol. It is concluded that NA enhances GABA responses by acting on noradrenergic alpha(2) and to a lesser extent beta receptors, whereas depressive action involves beta receptors only. These results confirm the hypothesis that the noradrenergic system participates in the regulation of the vestibulospinal and the vestibulo-ocular reflexes and suggest that conspicuous changes of NA content in brain due to aging or stress could lead to a deterioration in the mechanisms of normal vestibular function.

Acetyl-L-carnitine affects nonassociative learning processes in the leech Hirudo medicinalis.

Acetyl-L-carnitine is a natural molecule widely distributed in vertebrate and invertebrate nervous system. It is known to have significant effects on neuronal activity playing a role as neuroprotective and anti-nociceptive agent, as well as neuromodulatory factor. About its capability of affecting learning processes the available data are controversial. In the present study, we utilized the simplified model system of the leech Hirudo medicinalis to analyze the effects of acetyl-L-carnitine, assessing whether and how it might affect elementary forms of nonassociative learning processes. In leeches with the head ganglion disconnected from the first segmental ganglion, repetitive application of weak electrical shocks onto the caudal portion of the body wall induces habituation of swim induction whereas brush strokes on the dorsal skin produces sensitization or dishabituation when the nociceptive stimulus is delivered on previously habituated animals. Herein, the effects of different concentrations of acetyl-L-carnitine (2 mM - 0.05 mM) have been tested at different times on both sensitization and dishabituation. The results show that a single treatment of acetyl-L-carnitine blocked the onset of sensitization in a dose- and time-dependent manner. In fact, the most effective concentration able to block this process was 2 mM, which induced its major effects 11 days after the treatment, whereas 0.05 mM was unable to affect the sensitization process at all considered time points. On the contrary, acetyl-L-carnitine did not completely abolish dishabituation at the tested concentrations and at every time point. Finally, acetyl-L-carnitine also impaired the habituation of swim induction, but only 11 days after treatment.

High-permeability layers for remediation of ground water; go wide, not deep.

A nitrate-reactive porous media layer comprising wood particles with very high hydraulic conductivity (K approximately 1 cm/s) was used to successfully treat nitrate in a shallow sand-and-gravel aquifer in southern Ontario. Nitrate concentrations of 1.3 to 14 mg/L as N in the aquifer were attenuated to <0.5 mg/L as N in the reactive layer. Borehole dilution testing indicated that ground water velocities in the reactive layer, although variable, averaged five times higher than in the surrounding aquifer, suggesting that the layer was capturing ground water flow from deeper in the aquifer. The use of high-K reactive media opens up the possibility of installing permeable reactive barriers as horizontal layers in the shallow water table zone that do not necessarily have to penetrate the full depth of a contaminant plume to be effective. Model simulations show that the depth of capture of a high-K layer increases as the layer width in the direction of flow increases. Shallower emplacement could decrease barrier costs at some sites.

Acetyl-L-carnitine induces a sustained potentiation of the afterhyperpolarization.

Acetyl-L-carnitine is known to improve many aspects of the neural activity even if its exact role in neurotransmission is still unknown. This study investigates the effects of acetyl-L-carnitine in T segmental sensory neurons of the leech Hirudo medicinalis. These neurons are involved in some forms of neural plasticity associated with learning processes. Their physiological firing is accompanied by a large afterhyperpolarization that is mainly due to the Na+/K+ ATPase activity and partially to a Ca2+ -dependent K+ current. A clear-cut hyperpolarization and a significant increase of the afterhyperpolarization have been recorded in T neurons of leeches injected with 2 mM acetyl-L-carnitine some days before. Acute treatments of 50 microM acetyl-L-carnitine induced similar effects in T cells of naive animals. In the presence of apamin, a pharmacological blocker of Ca2+ -dependent K+ channel, acetyl-L-carnitine still enhanced the residual afterhyperpolarization, suggesting an effect of the drug on the Na+/K+ATPase. Acetyl-L-carnitine also increased the hyperpolarization induced by intracellular injection of Na+ ions. Therefore, acetyl-L-carnitine seems to be able to exert a positive sustained effect on the Na+/K+ ATPase activity in leech T sensory neurons. Moreover, in these cells, widely arborized, the afterhyperpolarization seems to play an important role in determining the action potential transmission at neuritic bifurcations. A computational model of a T cell has been previously developed considering detailed data for geometry and the modulation of the pump current. Herein, we showed that to a larger afterhyperpolarization, due to the acetyl-L-carnitine-induced effects, corresponds a decrement in the number of action potentials reaching synaptic terminals.

Morning recall of verbal material depends on prior sleep organization.

Despite the evidence that sleep may facilitate memory, controversial findings concern the role of sleep states (NREM, REM). We put forward the hypothesis that sleep organization, i.e. the regular occurrence of NREM-REM cycles, more than sleep states per se, may be crucial for the retention of verbal material presented before sleep. An experiment was performed in which recall of verbal material was requested of young subjects after three different kinds of night sleep: undisturbed sleep, fragmented sleep without sleep cycles disorganization, and fragmented sleep interrupted with sleep disorganization. Morning recall of verbal material was impaired after the night with disturbed sleep cycles, whereas it was not after the night with preserved sleep cycles; the amount of REM was similar in both cases. We conclude that the recall of verbal material is greatly affected by sleep cycle disorganization.

Pedigrees, propaganda, and paranoia: family studies in a historical context.

This article reviews the uses of family studies carried out in the early 20th century under the banner of eugenics, a companion discipline to early genetics. It explores how, in an attempt to analyze and quantify purportedly biologic bases of social problems, the eugenicists constructed pedigree charts of notoriously "defective" families. Investigation of individuals with suspect traits formed the basis for instruction of field workers who linked those traits to larger groups. The resulting eugenic family studies provided a "scientific" face for a popular hereditarian mythology that claimed to explain all social failure in systematic terms. The eugenicists were successful in fueling public fear about the growing "army of idiots and imbeciles" graphically depicted in their pedigree charts. Their success was the result of a finely crafted educational program--propaganda that reduced science to simplistic terms. The tendency to oversimplify concepts of genetic causation and the rush to amplify the significance of research findings through the popular media is also apparent today. What begins as publicity has the potential to be transformed into propaganda. Although many in the scientific community are understandably reluctant to revisit the abuses of the past, that community must confront the history of eugenics as a necessary antidote to the genetic hype that surrounds us.

Fetal heart rate tracings: observers versus computer assessment.

UNLABELLED: Cardiotocography (CTG) is widely used despite the fact that its diagnostic accuracy is far from satisfying. This is due, among other reasons, to the great intra- and interobserver variation in reading the fetal heart rate tracings. Computerized analysis might be a means to overcome the latter problem. OBJECTIVE: the present study was designed to assess the reproducibility of CTG readings among observers and between observers and a computer system. STUDY DESIGN: 63 fetal heart rate tracings were read by 4 clinicians (2 experienced and 2 inexperienced) and by the 2CTG computerized system. The variables considered were: baseline fetal heart rate (FHR), long-term variability (amplitude bandwidth around the baseline), number of large accelerations and number and type of decelerations. RESULTS: the agreement among observers, assessed by means of kappa coefficient, ranges from fair to good. The agreement between each of the observers and the computer readings, ranges from 0.18 to 0.48 for FHR baseline, from 0.16 to 0.74 for variability, from 0.37 to 0.64 for the number of accelerations and from 0.41 to 0.54 for the number of decelerations. The agreement on the type of decelerations is very low (0.01-0.25). CONCLUSION: it is concluded that interobserver variability between experienced observers, inexperienced observers and 2CTG is considerable and that the use of a computer system should overcome this problem.

Digestive tract endoluminal perfusion of cisapride (R 51619) and effects on gastrointestinal hormone levels in anaesthetized pigs.

The authors evaluated the in vivo effects of the new drug Cisapride on gastrointestinal hormone release in the mini-pig. Cisapride has been reported to stimulate and coordinate peristalsis of the GI tract. Selective endoluminal perfusion with Cisapride solution of the isolated but not denervated gastric antrum, duodenum and distal ileum demonstrated a significant increase of gastrin levels following perfusion of the gastric antrum and a decrease in vasoactive intestinal peptide following perfusion of the duodenum, only at very high doses.

Functional uncertainty, aging and memory processes during sleep.

Disorganized sleep patterns, can be found both during normal development and in pathological conditions. Aging could also be accompanied by a disorganization of the night sleep episode; sleep could be interrupted by spontaneous awakening, sleep cycle could be shortened or incomplete, sleep states modified. These patterns suggest an inability to sustain a stable condition, i.e. a condition of functional uncertainty. Biological and cognitive implications of functional uncertainty conditions are discussed. In particular, the hypothesis has been put forward that disturbances of sleep could have a detrimental role on memory. Recent results obtained in our lab support this hypothesis: recall is correlated with NREM-REM cycles proportion. Future research should ascertain the role of the functional uncertainty with respect to the kind of memory being involved during sleep, and establish how much and for which cognitive processes (including those involved in dream production) the inability to sustain a steady condition impairs the functioning during sleep. The duration of the functional uncertainty condition is also important. The long-term study of the link between functional uncertainty and cognitive resources, could be important for the understanding of the night life and for an adequate treatment of patients.