Advanced quantitative evaluation of PET systems using the ACR phantom and NiftyPET software

PURPOSE

A novel phantom-imaging platform, a set of software tools, for automated and high-precision imaging of the American College of Radiology (ACR) positron emission tomography (PET) phantom for PET/magnetic resonance (PET/MR) and PET/computed tomography (PET/CT) systems is proposed.

METHODS

The key feature of this platform is the vector graphics design that facilitates the automated measurement of the knife-edge response function and hence image resolution, using composite volume of interest templates in a 0.5 mm resolution grid applied to all inserts of the phantom. Furthermore, the proposed platform enables the generation of an accurate μ $\mu$ -map for PET/MR systems with a robust alignment based on two-stage image registration using specifically designed PET templates. The proposed platform is based on the open-source NiftyPET software package used to generate multiple list-mode data bootstrap realizations and image reconstructions to determine the precision of the two-stage registration and any image-derived statistics. For all the analyses, iterative image reconstruction was employed with and without modeled shift-invariant point spread function and with varying iterations of the ordered subsets expectation maximization (OSEM) algorithm. The impact of the activity outside the field of view (FOV) was assessed using two acquisitions of 30 min each, with and without the activity outside the FOV.

RESULTS

The utility of the platform has been demonstrated by providing a standard and an advanced phantom analysis including the estimation of spatial resolution using all cylindrical inserts. In the imaging planes close to the edge of the axial FOV, we observed deterioration in the quantitative accuracy, reduced resolution (FWHM increased by 1-2 mm), reduced contrast, and background uniformity due to the activity outside the FOV. Although it slows convergence, the PSF reconstruction had a positive impact on resolution and contrast recovery, but the degree of improvement depended on the regions. The uncertainty analysis based on bootstrap resampling of raw PET data indicated high precision of the two-stage registration.

CONCLUSIONS

We demonstrated that phantom imaging using the proposed methodology with the metric of spatial resolution and multiple bootstrap realizations may be helpful in more accurate evaluation of PET systems as well as in facilitating fine tuning for optimal imaging parameters in PET/MR and PET/CT clinical research studies.

Secretory microRNA Profiles of Third- and Fourth-Stage Dirofilaria immitis Larvae with Different Macrocyclic Lactone Susceptibility: In Search of Biomarkers for Early Detection of Infection

The canine heartworm, Dirofilaria immitis, is among the most important parasites of dogs in the United States and worldwide, and may cause severe and potentially fatal disease. Current diagnostic recommendations rely on serological detection of an adult female antigen, and visualization of microfilariae in the blood. Therefore, a reliable diagnosis can be only performed approximately six months post-infection. There is a growing need to characterize novel diagnostic markers that are capable of detecting the early stages of heartworm infection, in special markers associated with third-stage larvae (L3) and fourth-stage larvae (L4). The early detection of infection would guide medical interventions that could impede the development of patent infections and further parasite transmission. We cultured D. immitis L3 and L4 of two laboratorial strains with different susceptibility statuses to macrocyclic lactone drugs in vitro. Excretory/secretory microRNAs were sequenced and analyzed. We identified two miRNA novel candidates secreted abundantly by both L3 and L4 of both strains. These candidates were previously detected in the secretions of other D. immitis stages and one of them was found in the blood of D. immitis-infected dogs. These miRNAs have not been found in the secretions of other nematodes and could be D. immitis-specific diagnostic biomarkers, which could allow for the early detection of infection.

Training injury incidence in an amateur women's rugby union team in New Zealand over two consecutive seasons

OBJECTIVES

To describe the training injury incidence in amateur women's rugby union in New Zealand over two consecutive seasons.

DESIGN

A prospective cohort observational study METHODS: A total of 69 amateur women's rugby 15s team playerswere observed. Training exposure and training injury incidence were calculated.

RESULTS

The 38 training injuries resulted in a total injury incidence of 11.4 (8.3-15.6) per 1,000 training-hours. There were 12 injuries that resulted in a time-loss injury incidence of 3.6 (95% CI: 2.0-6.3) per 1,000 training-hours. Forwards recorded more total (RR: 1.8 [95% CI: 0.9-3.5]; p=0.0516) and time-loss (RR: 2.0 [95% CI: 0.6-6.6]; p=0.2482) injuries than Backs. The tackle was the most common injury cause for total (3.0 [95% CI: 1.6-5.6] per 1,000 training-hours.) injuries, but collisions (1.5 [95% CI: 0.6-3.6] per 1,000 training-hours.) with the ground or another person were the most common cause for time-loss injuries.The training injuries occurred most often to the lower limb and during the latter part of training sessions. These injuries were mostly minor in nature resulting in minimal time-loss away from training.

DISCUSSION

The time-loss injury incidence (3.6 per 1,000 training-hours.) for the amateur women's rugby 15s team players was higher than that reported for National (1.2 per 1,000 training-hours.) and Rugby World Cup for women (0.2 to 3.0 per 1,000 training-hours.) competitions.

CONCLUSION

The training injury incidence in amateur women's rugby union in New Zealand was higher than that reported for national and international rugby union injury incidences.

Thrombus formation on bioprosthetic aortic valves

Background

18F-GP1 is a novel radiotracer with a high affinity for the platelet glycoprotein IIb/IIIa receptor. Subclinical bioprosthetic valve thrombus has been postulated as a trigger for accelerated valve degeneration.

Purpose

To determine the feasibility of 18F-GP1 positron-emission tomography-computed tomography (PET-CT) for the detection of subclinical bioprosthetic aortic valve thrombus.

Methods

(i) Explanted degenerated aortic valve prostheses underwent histology and imaging. (ii) In a prospective observational study, patients with bioprosthetic aortic valve replacement (AVR) underwent echocardiography and 18F-GP1 PET-CT. Valves were assessed for hypoattenuating leaflet thickening (HALT), hypo-attenuation affection leaflet motion (HAM) and GP1 uptake.

Results

(i) GP1 correlated with thrombus on explanted valves (Figure). (ii) The first 6 patients (Table) were asymptomatic and had normally functioning surgical bioprostheses on echocardiography. At a median of 166 (range 122–189) days post-AVR, no patients had HALT or HAM on CT. There was avid focal GP1 uptake on the leaflets of all 6 patients which appeared most prominent along the leaflet edges (Figure). Only one patient had focal uptake in the valve frame, remote from the leaflets. In a separate cohort undergoing 18F-GP1 PET-CT for other conditions, there was no uptake on normal, native aortic valves (n=8).

Conclusion

For the first time, we demonstrate that 18F-GP1 PET-CT is a highly sensitive method of assessing platelet activation on bioprosthetic aortic valves. Despite the absence of CT evidence, early thrombus appeared to be a universal finding on recently implanted valve prostheses. The biological and clinical implications of subclinical bioprosthetic aortic valve thrombus have yet to be established.

GP1 uptake in AVR

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Dalton's and Amagat's laws fail in gas mixtures with shock propagation

A shock propagating through a gas mixture leads to pressure, temperature, and density increases across the shock front. Rankine-Hugoniot relations correlating pre- and post-shock quantities describe a calorically perfect gas but deliver a good approximation for real gases, provided the pre-shock conditions are well characterized with a thermodynamic mixing model. Two classic thermodynamic models of gas mixtures are Dalton's law of partial pressures and Amagat's law of partial volumes. We measure post-shock temperature and pressure in experiments with nonreacting binary mixtures of sulfur hexafluoride and helium (two dramatically disparate gases) and show that neither model can accurately predict the observed values, on time scales much longer than that of the shock front passage, due to the models' implicit assumptions about mixture behavior on the molecular level. However, kinetic molecular theory can help account for the discrepancy. Our results provide starting points for future theoretical work, experiments, and code validation.

TECRA® Unique™ Test for Rapid Detection of Salmonella in Food: Collaborative Study

The TECRA® Unique™ Salmonella test uses the principle of immunoenrichment to allow rapid detection of Salmonellae in food. A collaborative study was conducted to compare the TECRA Salmonella Unique test with the reference culture method given in the U.S. Food and Drug Administration's Bacteriological Analytical Manual. Three food types (milk powder, pepper, and soy flour) were analyzed in Australia and 2 food types (milk chocolate and dried egg) were analyzed in the United States. Forty-one collaborators participated in the study. For each of the 5 foods at each of the 3 levels, a comparison showed no significant differences (p ≥ 0.05) in the proportion of positive test samples for Unique and that for the reference method using the Chi-square test for independence with continuity correction.

VIDAS® Enzyme-Linked Immunofluorescent Assay for Detection of Listeria in Foods: Collaborative Study

The VIDAS LIS method and the traditional culture methods for detection of Listeria species in food were evaluated in a multilaboratory comparative study. The 6 foods tested were either naturally contaminated or inoculated with 3 different concentrations of Listeria. Results for each food and each contamination level with the VIDAS LIS method were as good as or better than those obtained with the traditional culture method. Of 1558 samples tested, 935 were positive: 839 by the VIDAS method and 809 by standard culture methods. Overall false negative rates were 10.3 and 13.5% for the VIDAS LIS and culture methods, respectively. The false positive rate for the VIDAS LIS assay was 1.4% based on 9 VIDAS LIS positive assays that did not confirm positive by isolation of Listeria. The agreement between the VIDAS LIS and culture methods for all samples tested was 86%.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Monoamines differentially modulate neuropeptide release from distinct sites within a single neuron pair

Monoamines and neuropeptides often modulate the same behavior, but monoaminergic-peptidergic crosstalk remains poorly understood. In Caenorhabditis elegans, the adrenergic-like ligands, tyramine (TA) and octopamine (OA) require distinct subsets of neuropeptides in the two ASI sensory neurons to inhibit nociception. TA selectively increases the release of ASI neuropeptides encoded by nlp-14 or nlp-18 from either synaptic/perisynaptic regions of ASI axons or the ASI soma, respectively, and OA selectively increases the release of ASI neuropeptides encoded by nlp-9 asymmetrically, from only the synaptic/perisynaptic region of the right ASI axon. The predicted amino acid preprosequences of genes encoding either TA- or OA-dependent neuropeptides differed markedly. However, these distinct preprosequences were not sufficient to confer monoamine-specificity and additional N-terminal peptide-encoding sequence was required. Collectively, our results demonstrate that TA and OA specifically and differentially modulate the release of distinct subsets of neuropeptides from different subcellular sites within the ASIs, highlighting the complexity of monoaminergic/peptidergic modulation, even in animals with a relatively simple nervous system.

A water-soluble, bay-functionalized perylenediimide derivative - correlating aggregation and excited state dynamics

The aggregation and the photophysics of a water soluble perylenediimide (PDI) derivative that features two bromine substituents in the bay positions has been probed. Non-fluorescent aggregates were found to be present at concentrations of 1.0 × 10^-5 M. In situ small-angle X-ray scattering (SAXS) measurements and complementary molecular modeling showed the presence of PDI aggregates. In their singlet excited states, the PDI aggregates are characterized by distinct transient fingerprints and rapid deactivation, as revealed by pump-probe experiments on the femto-, pico-, nano-, and microsecond timescales. The product of this deactivation is a PDI triplet excited state. The efficiency of the triplet formation depends on the concentration, and hence on the degree of aggregation. Notably, for PDI concentrations in the range of the critical micelle concentration, the efficiency of intersystem crossing is close to zero. In short, we have demonstrated, for the first time, aggregation-induced formation of triplet excited states for PDI derivatives.

Impact of major vascular resection on short- and long-term outcomes in patients with intrahepatic cholangiocarcinoma

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Background: Major vascular (IVC or portal vein) resection for Intrahepatic Cholangiocarcinoma (ICC) has traditionally been considered a relative contraindication to resection. We sought to define perioperative outcomes and survival of ICC patients undergoing liver surgery with major vascular resection using a multi-institutional database. Methods: 1,087 ICC patients who underwent liver resection between 1990-2016 were identified from 13 participating institutions. Multivariable logistic and cox regressions were used to determine the impact of major vascular resection on perioperative outcomes and long-term overall survival. Results: Of 1,087 patients who underwent resection, 128(11.8%) also underwent major vascular resection [21(16.4%)IVC resections, 98(76.6%)PV resections, 9(7.0%)combined resections]. One hundred eighty-seven(17.2%) patients received neoadjuvant therapy. Most patients underwent a major hepatectomy involving ≥ 3 liver segments(n = 664,61.1%). On final pathology, the majority of patients had T1(40.4%) or T2(35.5%) tumors; 194(17.8%) had lymph node metastasis. Patients undergoing major vascular resection had more advanced T3/T4 tumors [44(34.4%) vs. 137(14.3%) without resection;P < 0.001]. Of note, major vascular resection was not associated with the risk of any complication (OR .680,95%CI 0.32-1.45) or major complication (OR 0.69,95%CI 0.35-1.33); post-operative mortality was also comparable between groups (OR 1.06, 95%CI 0.32-3.48). In addition, median recurrence-free (14.0 months vs.14.7 months, HR.737,95%CI .49-1.10) and overall (33.4 months vs.40.2 months, HR .709,95%CI.36-1.40) survival were similar among patients who did and did not undergo major vascular resection, respectively(both P > 0.05). Conclusions: Among patients with ICC, major vascular resection was not associated with increased peri-operative morbidity or mortality at major centers. Long-term outcomes following resection of ICC requiring vascular resection were also comparable to outcomes following resection of tumors without vascular involvement. Concurrent major vascular resection should be considered in appropriately selected ICC patients.

The Influence of Head Impact Threshold for Reporting Data in Contact and Collision Sports: Systematic Review and Original Data Analysis

BACKGROUND

Head impacts and resulting head accelerations cause concussive injuries. There is no standard for reporting head impact data in sports to enable comparison between studies.

OBJECTIVE

The aim was to outline methods for reporting head impact acceleration data in sport and the effect of the acceleration thresholds on the number of impacts reported.

METHODS

A systematic review of accelerometer systems utilised to report head impact data in sport was conducted. The effect of using different thresholds on a set of impact data from 38 amateur senior rugby players in New Zealand over a competition season was calculated.

RESULTS

Of the 52 studies identified, 42% reported impacts using a >10-g threshold, where g is the acceleration of gravity. Studies reported descriptive statistics as mean ± standard deviation, median, 25th to 75th interquartile range, and 95th percentile. Application of the varied impact thresholds to the New Zealand data set resulted in 20,687 impacts of >10 g, 11,459 (45% less) impacts of >15 g, and 4024 (81% less) impacts of >30 g.

DISCUSSION

Linear and angular raw data were most frequently reported. Metrics combining raw data may be more useful; however, validity of the metrics has not been adequately addressed for sport. Differing data collection methods and descriptive statistics for reporting head impacts in sports limit inter-study comparisons. Consensus on data analysis methods for sports impact assessment is needed, including thresholds. Based on the available data, the 10-g threshold is the most commonly reported impact threshold and should be reported as the median with 25th and 75th interquartile ranges as the data are non-normally distributed. Validation studies are required to determine the best threshold and metrics for impact acceleration data collection in sport.

CONCLUSION

Until in-field validation studies are completed, it is recommended that head impact data should be reported as median and interquartile ranges using the 10-g impact threshold.

Using carbon nanodots as inexpensive and environmentally friendly sensitizers in mesoscopic solar cells

We discuss the use of carbon nanodots (CNDs) as sensitizers in mesoscopic solar cells. The CNDs are synthesized using a one-step, bottom-up microwave approach with citric acid, urea, and formic acid as precursors in aqueous media. Their light-harvesting capabilities can be tuned by adjusting the synthetic parameters. Comprehensive spectroscopic and theoretical studies allow us to rationalize the nature of their absorption features. Promising power conversion efficiencies (η) of 0.24% can be achieved from these cheap and eco-friendly sensitizers by optimizing the solar-cell assembly process. Interestingly, we found that extending the light absorption towards longer wavelengths does not necessarily improve the performance of the solar cells, since the longer-wavelength absorption features hardly contribute to the cells' photo-action spectra, so that the overall power conversion efficiency is actually worse. The origin of the lower performance is corroborated in transient absorption spectroscopy and photovoltage decay measurements. Our work points, on one hand, to the limits of as-synthesized CNDs as photosensitizers and, on the other hand, to possible improvements.

Abstract PD6-08: IMAGE: Individualized molecular analyses guide efforts in breast cancer with comprehensive genomic profiling of tissue and plasma tumor DNA

Background: Standard treatment options for patients with metastatic triple negative breast cancer (TNBC) are limited to chemotherapy. Molecular profiling of tumors may allow for novel treatment recommendations.

Methods: We initiated a prospective study designated IMAGE. Women with newly progressing metastatic TNBC who received at least one line of prior chemotherapy were eligible. New metastatic biopsies were obtained for molecular profiling at study entry. Archived metastatic biopsy specimens were allowed if patients had not commenced new systemic therapy. The specimens were reviewed by the study pathologist and stained for ER, PR, HER2, and androgen receptor (AR) by immunohistochemistry. Specimens underwent hybrid-capture based comprehensive genomic profiling (CGP) (Foundation Medicine Inc., Cambridge, MA). Clinical data and genomic profiling reports were reviewed by the GAITWAY (Genomic Alterations in Tumors with Actionable Yields) Molecular Profile Tumor Board. Recommendations were communicated to the treating oncologist and patients were followed for treatment decision and clinical outcomes. Peripheral blood was also analyzed by an investigational assay for circulating plasma tumor DNA (ptDNA) (Foundation Medicine Inc.) at study entry, and when obtainable, from serial blood draws at time of progression. The primary objective was to assess feasibility of completing the process from consent to GAITWAY recommendations within 28 days for at least 80% of patients.

Results: From September 2013 to April 2015, we enrolled 26 eligible women. Median age was 55 (range 25-67); patients identified as white 12 (46%), black 11 (42%), or other 3 (12%); median number of prior lines of treatment was 3; and 65.4% of patients had visceral disease. Twenty (77%) eligible patients received CGP of a metastatic site biopsy. Six patients did not undergo CGP due to either absence of a metastatic site amenable for biopsy or inadequate tissue for CGP. The study met the predefined statistical endpoint for futility and was closed after 20 patients had undergone CGP. Twelve (60%) evaluable patients received treatment recommendations within 28 days of study consent. Failure to meet this time frame was due to difficulties in accessing archival tumor tissue (N=5) and need for additional tissue for molecular analysis (N=3). Preliminary results demonstrate high concordance between mutations in metastatic biopsies and ptDNA in 15/17 patients.

Enrolled in IMAGE26Successful NGS20Potentially actionable mutation identified15GAITWAY recommended targeted therapy as possible next treatment13Received targeted therapy4

Conclusions: CGP of patients with metastatic TNBC can provide additional information that may help direct treatment. However, difficulties in obtaining adequate tumor tissue may hinder this approach. Use of a well-validated ptDNA profiling assay could be an alternative to overcome these limitations.

Citation Format: Parsons HA, Beaver JA, Cimino-Mathews A, Zorzi J, Slater S, Clark T, Lipson D, Ali SM, Kennedy M, Otto GA, Young LE, Jeter S, VanDenBerg DA, Rosner GL, Park BH, Stearns V. IMAGE: Individualized molecular analyses guide efforts in breast cancer with comprehensive genomic profiling of tissue and plasma tumor DNA. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD6-08.

Management of cardiac arrest survivors in UK intensive care units: a survey of practice

BACKGROUND

Cardiac arrest is a common presentation to intensive care units. There is evidence that management protocols between hospitals differ and that this variation is mirrored in patient outcomes between institutions, with standardised treatment protocols improving outcomes within individual units. It has been postulated that regionalisation of services may improve outcomes as has been shown in trauma, burns and stroke patients, however a national protocol has not been a focus for research. The objective of our study was to ascertain current management strategies for comatose post cardiac arrest survivors in intensive care in the United Kingdom.

METHOD

A telephone survey was carried out to establish the management of comatose post cardiac arrest survivors in UK intensive care units. All 235 UK intensive care units were contacted and 208 responses (89%) were received.

RESULTS

A treatment protocol is used in 172 units (82.7%). Emergency cardiology services were available 24 hours a day, 7 days a week in 54 (26%) hospitals; most units (123, 55.8%) transfer patients out for urgent coronary angiography. A ventilator care bundle is used in 197 units (94.7%) and 189 units (90.9%) have a policy for temperature management. Target temperature, duration and method of temperature control and rate of rewarming differ between units. Access to neurophysiology investigations was poor with 91 units (43.8%) reporting no availability.

CONCLUSIONS

Our results show that treatments available vary considerably between different UK institutions with only 28 units (13.5%) able to offer all aspects of care. This suggests the need for 'cardiac arrest care bundles' and regional centres to ensure cardiac arrests survivors have access to appropriate care.

The interface of inflammation and subclinical atherosclerosis in granulomatosis with polyangiitis (Wegener's): a preliminary study

The objective of this study is to assess the relationship between inflammatory disease in granulomatosis with polyangiitis (GPA, Wegener's) and the development of subclinical atherosclerosis. A total of 46 adult patients with GPA were enrolled. Disease status was measured by Birmingham vasculitis assessment scores as modified for GPA, vasculitis damage index, disease duration, and number of relapses. Classic atherosclerotic risk factors, platelet aggregation responses, and circulating microparticle (MP) levels were recorded. All patients underwent carotid artery intima-media thickness (IMT) measurement as outcome for subclinical atherosclerosis. In univariate analyses, systolic and diastolic blood pressure, creatinine, and age were significantly associated with higher IMT (ρ values 0.37, 0.38, 0.35, and 0.054, respectively [P < 0.02 for all]). In a multiple regression model, greater number of relapses, older age at the onset of disease, and higher diastolic blood pressure were found to be associated with higher IMT (P values 0.003, <0.001, and 0.031, respectively). MP counts and platelet reactivity correlated well with disease activity in GPA. Furthermore, MPs were found to activate vascular endothelial cells and platelets in vitro. The cumulative burden of systemic inflammation in GPA correlated with the development of subclinical atherosclerosis. The correlation with subclinical atherosclerosis could be because of glucocorticoid use and not the inflammatory process in GPA, giving the inherent bias that exits with the use of glucocorticoid with each relapse. The findings of increased levels of circulating leukocyte-derived MPs and enhanced platelet reactivity during relapse suggest possible roles for MPs and platelets in disease pathogenesis and support a growing literature that links inflammation, atherosclerosis, and platelet activation. This hypothesis is further substantiated by our demonstration that MPs isolated from plasma of GPA patients can activate platelets and vascular endothelial cells.

Use of the King-Devick test for sideline concussion screening in junior rugby league

AIM

To determine whether the King-Devick (K-D) test used as a sideline test in junior rugby league players over 12 matches in a domestic competition season could identify witnessed and incidentally identified episodes of concussion.

METHODS

A prospective observational cohort study of a club level junior rugby league team (n=19) during the 2014 New Zealand competition season involved every player completing two pre-competition season baseline trials of the K-D test. Players removed from match participation, or who reported any signs or symptoms of concussion were assessed on the sideline with the K-D test and referred for further medical assessment. Players with a pre- to post-match K-D test difference >3s were referred for physician evaluation.

RESULTS

The baseline test-retest reliability of the K-D test was high (rs=0.86; p<0.0001). Seven concussions were medically identified in six players who recorded pre- to post-match K-D test times greater than 3s (mean change of 7.4s). Post-season testing of players demonstrated improvement of K-D time scores consistent with learning effects of using the K-D test (67.7s vs. 62.2s).

DISCUSSION

Although no witnessed concussions occurred during rugby play, six players recorded pre- to post-match changes with a mean delay of 4s resulting in seven concussions being subsequently confirmed post-match by health practitioners. All players were medically managed for a return to sports participation.

CONCLUSION

The K-D test was quickly and easily administered making it a practical sideline tool as part of the continuum of concussion assessment tools for junior rugby league players.

Correction: Influences on and patterns in total gaseous mercury (TGM) at Harwell, England

Correction for ‘Influences on and patterns in total gaseous mercury (TGM) at Harwell, England’ by J. Kentisbeer et al., Environ. Sci.: Processes Impacts, 2015, DOI: 10.1039/c4em00652f.

Influences on and patterns in total gaseous mercury (TGM) at Harwell, England

Total gaseous mercury (TGM) was monitored during 2013 at the rural monitoring site, Harwell, England using the Tekran 2537A monitoring system. Average TGM for the year was 1.45 ± 0.24 ng m(-3). This is comparable to other northern hemisphere studies, but on average 0.5 ng m(-3) higher than at its sister monitoring station at Auchencorth Moss, Scotland, but 14% lower than that found in a similar study at the same location of 1.68 ng m(-3) in 1995/6. Using wind sector analysis we show the important influence of local emissions, with our data showing that the largest influence on TGM observed is that of the adjacent Science & Innovation campus, making the site more a 'suburban background'. By using co-located measurements of black carbon and sulphur dioxide as tracers, we present an initial investigation into the impact of the closure of Didcot A coal fired power station, which ceased operating in March 2013. Further analysis using air mass back trajectories shows the long-range contribution to TGM from continental Europe, and that the lowest levels are associated with marine air masses from the west.

Molecular wires – impact of π-conjugation and implementation of molecular bottlenecks

We highlight recent progress in the field of electron transport through molecular bridges as integrative parts of electron donor–bridge–acceptor conjugates.