Accuracy of chest x-ray screening of silica-exposed miners for tuberculosis.

BACKGROUND: The World Health Organization recommends systematic chest X-ray (CXR) screening for tuberculosis (TB) in silica-exposed workers. However, evidence on the accuracy of CXR screening in such populations is lacking. AIMS: To measure the accuracy of CXR screening for active TB in silica-exposed miners, in a population with a high prevalence of silicosis, post-TB lung disease and HIV. METHODS: A secondary analysis of data from a miner screening programme in Lesotho was undertaken. We measured the performance of CXR (in participants with and without cough) for 'abnormalities suggestive of TB' against Xpert MTB/RIF (Xpert). The sample size was 2572 and positive Xpert prevalence was 3%. RESULTS: CXR alone had high sensitivity (0.93, 95% confidence interval [CI] 0.87-0.99), but low specificity (0.41, 95% CI 0.39-0.42). Requiring cough and a positive CXR increased specificity (0.79, 95% CI 0.77-0.81), resulting in reduced sensitivity (0.41, 95% CI 0.30-0.52). There was no difference in CXR accuracy by HIV status. However, specificity was markedly reduced in the presence of silicosis (from 0.70, 95% CI 0.68-0.72, to 0.03, 95% CI 0.02-0.04) or past TB history (from 0.59, 95% CI 0.56-0.62 to 0.27, 95% CI 0.25-0.29). Throughout, positive predictive value remained very low (5%) and negative predictive value very high (99%). CONCLUSIONS: CXR screening accurately identifies TB-negative CXRs in this population, but post-TB lung disease and silicosis would result in a high proportion of Xpert-negative referrals and an increased risk of unneeded empirical treatment. Adapted screening algorithms, practitioner training and digital access to previous mining CXRs are needed.

Measurement of the ν_{e}-Nucleus Charged-Current Double-Differential Cross Section at ⟨E_{ν}⟩=2.4 GeV Using NOvA.

The inclusive electron neutrino charged-current cross section is measured in the NOvA near detector using 8.02×10^{20} protons-on-target in the NuMI beam. The sample of GeV electron neutrino interactions is the largest analyzed to date and is limited by ≃17% systematic rather than the ≃7.4% statistical uncertainties. The double-differential cross section in final-state electron energy and angle is presented for the first time, together with the single-differential dependence on Q^{2} (squared four-momentum transfer) and energy, in the range 1 GeV≤E_{ν}<6 GeV. Detailed comparisons are made to the predictions of the GENIE, GiBUU, NEUT, and NuWro neutrino event generators. The data do not strongly favor a model over the others consistently across all three cross sections measured, though some models have especially good or poor agreement in the single differential cross section vs Q^{2}.

Reforming the workers' compensation process for occupational lung disease among miners in South Africa: an efficiency study of claims assessment.

PURPOSE: The large burden of silicosis and tuberculosis (TB) in the South African mining industry, coupled with an under-resourcing of the compensation agencies responsible for certifying occupational lung disease, have resulted in serious backlogs. This work aimed to measure the efficiency gains from triaging occupational lung disease claims using claim type, years of mining exposure and computer aided detection (CAD) to save on scarce medical adjudicators. METHODS: During 2020, the compensation authority started to triage claims for TB and those of miners with < 10 years of service to two-person panels instead of the four-person panel plus radiologist used previously. Efficiency gain was calculated in medical person-units saved and reduction in delays. Different service thresholds predictive of silicosis were simulated, as well as the impact of pre-classification of chest X-rays with CAD using different combinations of sensitivity and specificity. RESULTS: The new triage system saved 20.3% in person-time units and reduced delays by 10-20 days. Without CAD the greatest efficiency gain (28%) was projected from dispensing with a mining service threshold and routing all non-TB claims to the small panels at the outset. Simulation of four different CAD sensitivity/specificity combinations yielded efficiency gains of 18.2-36.1%, with 31.1% judged the most realistic. Use of sensitivity of close to 100% would not be feasible because of the very low resulting specificity. CONCLUSION: Pre-adjudication triage of claims at the compensation agency is capable of saving a substantial proportion of adjudicator time and reducing certification delays. Additional efficiency gains are achievable by referring all claims to small panels to begin with and improvement of CAD performance for this ex-miner population.

Search for Active-Sterile Antineutrino Mixing Using Neutral-Current Interactions with the NOvA Experiment.

This Letter reports results from the first long-baseline search for sterile antineutrinos mixing in an accelerator-based antineutrino-dominated beam. The rate of neutral-current interactions in the two NOvA detectors, at distances of 1 and 810 km from the beam source, is analyzed using an exposure of 12.51×10^{20} protons-on-target from the NuMI beam at Fermilab running in antineutrino mode. A total of 121 of neutral-current candidates are observed at the far detector, compared to a prediction of 122±11(stat.)±15(syst.) assuming mixing only between three active flavors. No evidence for ν[over ¯]_{µ}→ν[over ¯]_{s} oscillation is observed. Interpreting this result within a 3+1 model, constraints are placed on the mixing angles θ_{24}<25° and θ_{34}<32° at the 90% C.L. for 0.05 eV^{2}≤Δm_{41}^{2}≤0.5 eV^{2}, the range of mass splittings that produces no significant oscillations at the near detector. These are the first 3+1 confidence limits set using long-baseline accelerator antineutrinos.

Understanding the effects of neutron scattering for neutron-yield-isotropy measurements at the NIF.

Neutron-yield diagnostics at the NIF have been upgraded to include 48 detectors placed around the NIF target chamber to assess the DT-neutron-yield isotropy for inertial confinement fusion experiments. Real-time neutron-activation detectors are used to understand yield asymmetries due to Doppler shifts in the neutron energy attributed to hotspot motion, variations in the fuel and ablator areal densities, and other physics effects. In order to isolate target physics effects, we must understand the contribution due to neutron scattering associated with the different hardware configurations used for each experiment. We present results from several calibration experiments that demonstrate the ability to achieve our goal of 1% or better precision in determining the yield isotropy.

Workers' compensation claims for occupational tuberculosis in South African health workers: Outcomes and workers' experiences.

BACKGROUND: Given the elevated risk of tuberculosis (TB), including drug-resistant disease, experienced by health workers in South Africa (SA), effective workers' compensation for occupational TB is a legal right and an essential social benefit. OBJECTIVES: To investigate the experience of the workers' compensation system among health workers who suffered from TB while working in public service facilities in Western Cape Province, SA. METHODS: In this case series with a qualitative component, 300 claims for occupational TB in health workers were sampled from the provincial health department database of claims submitted. Claim status for each case was ascertained. An attempt was made to contact each health worker for a telephonic interview consisting of both closed- and open-ended (qualitative) questions. Fifty-one interviews were completed. RESULTS: In nearly half of the cases, there was no record of claim status on the state Compensation Fund website. Of the 51 interviewees, only one had received all the compensation benefits for their particular claim circumstances. Health workers' experience of having their cases reported for compensation purposes was marred by perception of poor communication and administration. The experience of contracting TB was further characterised by surprise, perceptions of stigma, financial burden and ongoing ill-health. CONCLUSIONS: Affected health workers' experience of the workers' compensation system was mostly negative, adding to the burden of being ill with TB. Education of management and clinicians, improvement in communication, and timeous and regular checking of claim status and of payment of applicable compensation are required at the provincial level. Dedicated facility-based occupational health units are needed, with a staff complement of knowledgeable persons trusted by their colleagues. However, the effectiveness of the system is ultimately dependent on the ability of the Compensation Fund to register and display claims timeously and administer compensation expeditiously.

Computer-aided detection for tuberculosis and silicosis in chest radiographs of gold miners of South Africa.

BACKGROUND: For over one hundred years, the gold mining sector has been a considerable source of tuberculosis (TB) and silicosis disease burden across Southern Africa. Reading chest radiographs (CXRs) is an expert and time-intensive process necessary for the screening and diagnosis of lung disease and the provision of evidence for compensation claims. Our study explores the use of computer-aided detection (CAD) of TB and silicosis in CXRs of a population with a high incidence of both diseases.METHODS: A set of 330 CXRs with human expert-determined classifications of silicosis, TB, silcotuberculosis and normal were provided to four health technology companies. The ability of each of their respective CAD systems to predict disease was assessed using receiver operating characteristic curve analysis of the under the curve metric.RESULTS: Three of the four systems differentiated accurately between TB and normal images, while two differentiated accurately between silicosis and normal images. Inclusion of silicotuberculosis images reduced each system's ability to detect either disease. In differentiating between any abnormal from normal CXR, the most accurate system achieved both a sensitivity and specificity of 98.2%.CONCLUSION: The current ability of CAD to differentiate between TB and silicosis is limited, but its use as a mass screening tool for both diseases shows considerable promise.

Occupational lung disease among Basotho ex-miners in a large outreach medical assessment programme

Background: Current initiatives in southern Africa to medically assess former migrant miners for silicosis and tuberculosis, including statutory and lawsuit derived compensation programmes, require burden of disease information. nObjective: To use clinical information collected on ex-miners examined at the Occupational Health Service Centre (OHSC) in Lesotho, operated under the Tuberculosis in Mining Sector in Southern Africa (TIMS) project, to measure the burden of lung disease and respiratory impairment. Methods: Demographic, occupational and medical history information, chest radiology, spirometry, GeneXpert testing for tuberculosis, and pulse oximetry outcomes were analysed, and descriptive summary measures calculated, in a group of ex-miners examined in 2017 and 2018. Results: The study sample comprised 2 758 Basotho former underground miners, with median age of 62 years and median length of service of 28 years. Among ex-gold miners (n = 2 678), disease prevalence was high: radiological tuberculosis (consistent with previous or current disease) 60.9%, silicosis 42.5%, HIV 30.7%, silicotuberculosis 25.7%, and current active tuberculosis 6.8%. Of those with tuberculosis diagnosed microbiologically, 6.7% had no radiological evidence of tuberculosis and 54.1% did not report cough. Conclusion: The findings have public health and compensation implications. There are large numbers of ex-miners with potentially compensable disease under both the statutory system and a settlement trust set up following litigation. This overlaps with a tuberculosis-HIV co-epidemic which requires screening and treatment for tuberculosis and HIV, and managing a considerable disability and care burden on families and the Lesotho health system. Coordinated planning and substantial resources are needed for these programmes to do justice to their mandates

Simultaneous visualization of wall motion, beam propagation, and implosion symmetry on the National Ignition Facility (invited).

Achieving a symmetric implosion in National Ignition Facility indirect drive targets requires understanding and control of dynamic changes to the laser power transport in the hohlraum. We developed a new experimental platform to simultaneously visualize wall-plasma motion and dynamic laser power transport in the hohlraum and are using it to investigate correlations of these measurements with the imploded capsule symmetry. In a series of experiments where we made one single parameter variation, we show the value of this new platform in developing an understanding of laser transport and implosion symmetry. This platform also provides a new way to evaluate dynamic performance of advanced hohlraum designs.

On the system stability and calibration of the image plate/scanner system for plasma diagnosis at the National Ignition Facility.

At the National Ignition Facility (NIF), storage phosphor image plates (IP) are used extensively for recording x-rays, charged particles, and neutrons. For x-ray imaging and spectroscopy, absolute and relative calibrations are important for extracting plasma information from the diagnostics. We use Fuji MS, SR, and TR image plates that have been cut to fit custom diagnostic envelopes. The image plates are scanned on a General Electric FLA 7000 IP flying spot scanner. Calibrations for sensitivity, spatial scale, and temperature dependent fade are applied. During a set of recent calibrations, we noticed large shifts in the absolute calibration of the image plate system. The possible source of these shifts is discussed. We discuss scanner stability and a method for calibration. We discuss the fade and temperature effects of the image plates and how this correction is applied within the NIF environment. We also compare our NIF GE FLA 7000 IP scanner with a new General Electric Amersham Typhoon IP scanner.

Digital radiological surveillance of silicosis and related tuberculosis in the South African mining industry practical and technical considerations

The switch from analogue to digital radiography formats for surveillance for silicosis and tuberculosis in the South African mining industry raised the question of equivalence of formats for this purpose. As a result, the South African Mine Health and Safety Council (MHSC) sponsored a study, recently published, on the equivalence of digital and analogue radiography in this setting. This commentary aims to provide a summary of the study findings, accompanied by an overview of the practical considerations that arise in the use of digital radiographic surveillance in the South African mining industry. Through a clear understanding of the objectives of surveillance, use of quality and reference standards for hardware and software, and interpretation of digital images, avoidance of common pitfalls, and use of all the clinical and occupational health information on each miner, the contribution of surveillance to identification and control of silicosis and tuberculosis in the mining industry can be maximised

Constraints on Oscillation Parameters from ν_{e} Appearance and ν_{µ} Disappearance in NOvA.

Results are reported from an improved measurement of ν_{µ}→ν_{e} transitions by the NOvA experiment. Using an exposure equivalent to 6.05×10^{20} protons on target, 33 ν_{e} candidates are observed with a background of 8.2±0.8 (syst.). Combined with the latest NOvA ν_{µ} disappearance data and external constraints from reactor experiments on sin^{2}2θ_{13}, the hypothesis of inverted mass hierarchy with θ_{23} in the lower octant is disfavored at greater than 93% C.L. for all values of δ_{CP}.

Rhabdomyolysis with acute tubular necrosis following occupational inhalation of thinners.

Thinners are mixtures of organic solvents commonly containing toluene, xylene, acetone, hexane, benzene and methyl isobutyl ketone. This report describes a case of rhabdomyolysis with acute tubular necrosis and renal failure, most likely attributable to toluene, following occupational exposure to thinners while cleaning a steel water tank. These adverse health effects have previously been reported following acute poisoning or intentional inhalation by drug abusers, but rarely in the occupational setting. Poor working conditions, lack of health and safety training and delayed treatment contributed to the onset and severity of the patient's complications. This case emphasizes the need for strict control measures, including adequate ventilation, training on working in confined spaces, appropriate personal protective equipment and emergency rescue procedures in such settings. In addition, rhabdomyolysis, acute tubular necrosis and renal failure should be added to safety data material as possible complications of excessive inhalation of thinners.

Measurement of the Neutrino Mixing Angle θ_{23} in NOvA.

This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of 6.05×10^{20} protons on target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal θ_{23} mixing (θ_{23}=π/4). Assuming the normal mass hierarchy, we find Δm_{32}^{2}=(2.67±0.11)×10^{-3} eV^{2} and sin^{2}θ_{23} at the two statistically degenerate values 0.404_{-0.022}^{+0.030} and 0.624_{-0.030}^{+0.022}, both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6σ significance.

Aflibercept as a Second Line Therapy for Neovascular Age Related Macular Degeneration in Israel (ASLI) study.

PurposeThe purpose of this study is to evaluate an early switch to aflibecept in eyes with neovascular age-related macular degeneration (nvAMD) showing partial or lack of response for initial therapy with bevacizumab.MethodsThe Aflibercept as a Second Line Therapy for Neovascular Age Related Macular Degeneration in Israel (ASLI) was a prospective, multicenter, single-arm clinical trial. Eyes with nvAMD having incomplete response to 3-9 prior bevacizumab injections were recruited. Three monthly intravitreal aflibercept (2 mg) injections were administered, followed by two bi-monthly injections and a final examination at week 28. An optional injection was allowed at week 20.ResultsForty-seven eyes of 46 patients (mean±SD age 76±8 years) were recruited. The mean number of prior bevacizumab injections was 5.5±2.9. The mean visual acuity improved from 60.3±10 ETDRS letters at baseline to 63.1±15 letters at week 28 (P=0.02, paired t-test). The central subfield thickness (CST) reduced from 409±127 micron at baseline to 330±110 microns at week 4 (P=0.0002; paired t-test), and 277±70 microns at week 28 (P=0.00002; paired t-test). Twenty-two eyes had three to five prior bevacizumab injections (mean 5.1±0.7), and 25 eyes had six to nine prior injections (7.32±1.2). Both groups had reduced CST from baseline to week 28 (P=0.0004 and P=0.0007; paired t-test, respectively). Thirty-five (75%) eyes required the optional additional aflibercept injection at week 20.ConclusionsThe ASLI study demonstrated improved BCVA and reduced CST following an early switch to aflibercept therapy in eyes with prior incomplete response to initial therapy with three to nine bevacizumab injections.

Participatory theatre and tuberculosis: a feasibility study with South African health care workers.

SETTING: Health care workers (HCWs) in South Africa have a risk of acquiring tuberculosis (TB) that is twice that of the general population. Nonetheless, adherence to infection control and TB disclosure requirements remain problematic. OBJECTIVE: To gain insight into the feasibility of an educational participatory theatre intervention to reduce the risk of occupational TB. DESIGN: An intervention using participatory theatre was developed progressively over six consecutive sessions with different groups of HCWs, totalling 83 participants. Videos of the sessions, field notes, observations, interviews and a post-experience survey were analysed to ascertain feasibility. RESULTS: The intervention was acceptable to participants, met a defined demand, proved adaptable to the target group and was practical if done during working hours or if integrated into already existing training sessions. The theatre work shed light on where to focus educational interventions. Preliminary efficacy outcomes included strengthened social cohesion via group work and reports of subsequent greater vigilance regarding occupational TB. CONCLUSION: Participatory theatre techniques may offer a useful, culturally appropriate supplement to existing educational approaches to the prevention and management of occupational TB. Given the limitations in resources and our assessment of feasibility, training existing health care educators in such techniques would be a promising next step.

Observation of hohlraum-wall motion with spectrally selective x-ray imaging at the National Ignition Facility.

The high fuel capsule compression required for indirect drive inertial confinement fusion requires careful control of the X-ray drive symmetry throughout the laser pulse. When the outer cone beams strike the hohlraum wall, the plasma ablated off the hohlraum wall expands into the hohlraum and can alter both the outer and inner cone beam propagations and hence the X-ray drive symmetry especially at the final stage of the drive pulse. To quantitatively understand the wall motion, we developed a new experimental technique which visualizes the expansion and stagnation of the hohlraum wall plasma. Details of the experiment and the technique of spectrally selective x-ray imaging are discussed.

Fate of Outstanding COIDA Occupational Disease Claims Following Closure of the Western Cape Provincial Medical Advisory Panel in 2008 : An audit

Background and objectives: The Western Cape Provincial Medical Advisory Panel (PMAP) was established in 2004 in terms of Section 70(1) of COIDA. A primary function was to improve the efficiency of medical assessment of occupational disease claims. The PMAP was closed by the Compensation Commissioner in 2008. This audit aimed to determine the fate of claims outstanding at the time of closure. Methods: A total of 68 claims outstanding in April 2008 were followed up by telephone; email and/or internet to determine what proportion had progressed or; if accepted; had resulted in a permanent disablement compensation payment. Results: Of the 68 claims; 31 (44) were confirmed as having progressed. Of these; payment of permanent disablement awards could be confirmed in only 15 claims (22). The remaining 56 either showed no progress or no longer had a record in the COIDA system. Those stages of the claims process that had previously been aided by PMAP functioning had deteriorated in efficiency. Conclusions: Overall; the low proportion of outstanding claims finalised and awarded is consistent with inefficiency in claims handling of occupational disease; a finding echoed by recent complaints about general Compensation Fund performance from both healthcare providers and parliamentary investigation

Deep vein thrombosis following prolonged kneeling: a case report.

This report describes a fibreglass mould maker in the yacht building industry who developed a deep vein thrombosis (DVT) after 6 weeks of working in a kneeling position. We propose that his prolonged kneeling combined with constrictive knee pad straps caused vascular compression, precipitating his DVT. A hypercoagulability diathesis was suspected but not confirmed. Operator and employer education, modified work practices and strapless knee pads are suggested as possible preventive measures.