Rapid-bTB: a novel lateral flow test able to differentiate Mycobacterium bovis from Mycobacterium tuberculosis in sputum

Background: A novel lateral flow, immunochromatographic assay (LFD) specific for Mycobacterium bovis, the cause of bovine tuberculosis and zoonotic TB, was recently developed at Queen’s University Belfast. The LFD detects whole M. bovis cells, in contrast to other commercially available LFD tests (BD MGITTM TBc ID, SD Bioline TB Ag MPT 64, Capilia TB-Neo kit) which detect MPT64 antigen secreted during growth. The new LFD test has been evaluated in the veterinary context, and its specificity for M. bovis in the broadest sense (i.e. subsp. bovis, subsp. caprae and BCG) and sensitivity to detect M. bovis in positive MGIT™ liquid cultures was demonstrated comprehensively.
Methods: Preliminary work was carried out by researchers at Queen’s University Belfast to optimise sputum sample preparation, estimate the limit of detection (LOD) of the LFD with M. bovis-spiked sputum samples, and check LFD specificity by testing a broad range of non-tuberculous Mycobacterium spp. (NTM) and other bacterial genera commonly encountered in sputum samples (Haemophilus, Klebsiella, Pseudomonas, Staphylococcus). In the Cameroon laboratory direct detection of M. bovis in human sputa was attempted, and 50 positive sputum MGIT™ cultures and 33 cultures of various Mycobacterium spp. originally isolated from human sputa were tested.
Results: Sputum sample preparation consisted of digestion with 1% NALC for 30 min, centrifugation at 3000g for 20 min, PBS wash, centrifugation again, and pellet resuspended in KPL blocking buffer before 100 µl was applied to the LFD. The LOD of the LFD applied to M. bovis-spiked sputum was estimated to be 104 CFU/ml. A small number of confirmed Ziehl-Neelsen ‘3+’ M. bovis positive sputum samples were tested directly but no positive LFD results were obtained. All of the sputum MGIT™ cultures and mycobacterial cultures (including M. tuberculosis, M. africanum, M. bovis, M. intracellulare, M. scrofulaceum, M. fortuitum, M. peregrinum, M. interjectum) tested LFD negative when read after 15 min except for the M. bovis cultures, thereby confirming specificity of LFD for M. bovis in the clinical microbiology context.
Conclusions: Results indicate that the ‘Rapid-bTB’ LFD is a very specific test, able to differentiate M. bovis from M. tuberculosis, M. africanum, and a range of NTM isolated from human sputa in MGITTM liquid cultures. However, the LFD lacks sufficient sensitivity to be applied earlier in the diagnostic process to directly test human sputa.

Cybersecurity Test-Bed for IEC 61850 based Smart Substations

With the development and deployment of IEC 61850 based smart substations, cybersecurity vulnerabilities of supervisory control and data acquisition (SCADA) systems are increasingly emerging. In response to the emergence of cybersecurity vulnerabilities in smart substations, a test-bed is indispensable to enable cybersecurity experimentation. In this paper, a comprehensive and realistic cyber-physical test-bed has been built to investigate potential cybersecurity vulnerabilities and the impact of cyber-attacks on IEC 61850 based smart substations. This test-bed is close to a real production type environment, and has the ability to carry out end-to-end testing of cyber-attacks and physical consequences. A fuzz testing approach is proposed for detecting IEC 61850 based intelligent electronic devices (IEDs) and validated in the proposed test-bed.

The time course of conflict on the Cognitive Reflection Test

Reasoning that is deliberative and reflective often requires the inhibition of intuitive responses. The Cognitive Reflection Test (CRT) is designed to assess people’s ability to suppress incorrect heuristic responses in favour of deliberation. Correct responding on the CRT predicts performance on a range of tasks in which intuitive processes lead to incorrect responses, suggesting indirectly that CRT performance is related to cognitive control. Yet little is known about the cognitive processes underlying performance on the CRT. In the current research, we employed a novel mouse tracking mjavascript:void(0);ethodology to capture the time-course of reasoning on the CRT. Analysis of mouse cursor trajectories revealed that participants were initially drawn towards the incorrect (i.e., intuitive) option even when the correct (deliberative) option was ultimately chosen. Conversely, participants were not attracted to the correct option when they ultimately chose the incorrect intuitive one. We conclude that intuitive processes are activated automatically on the CRT and must be inhibited in order to respond correctly. When participants responded intuitively, there was no evidence that deliberative reasoning had become engaged.

On Passive Intermodulation Test of Analog and Digital Systems

This paper presents initial results of evaluating suitability of the conventional two-tone CW passive intermodulation (PIM) test for characterization of modulated signal distortion by passive nonlinearities in base station antennas and RF front-end. A comprehensive analysis of analog and digitally modulated waveforms in the transmission lines with weak distributed nonlinearity has been performed using the harmonic balance analysis and X-parameters in Advanced Design System (ADS) simulator. The nonlinear distortion metrics used in the conventional two-tone CW PIM test have been compared with the respective spectral metrics applied to the modulated waveforms, such as adjacent channel power ratio (ACPR) and error vector magnitude (EVM). It is shown that the results of two-tone CW PIM tests are consistent with the metrics used for assessment of signal integrity of both analog and digitally modulated waveforms.

Temperament test for re-homed dogs validated through direct behavioral observation in shelter and home environment

This study was the first attempt to carry out a validation of a temperament test (TT) for shelter dogs that addressed the topics of inter- and intra-raters agreements, test-retest reliability, and validity. The TT consisted of 22 subtests. Each dog was approached and handled by an unfamiliar person and made to interact with a same- and an opposite-gender conspecific. Dogs were tested twice in the shelter and once in their new homes 4 months after adoption to evaluate consistency in behavioral assessment. Playfulness, trainability, problem solving abilities, food possessiveness, and reactivity to sudden stimuli were also evaluated. Testers scored dogs' responses in terms of confidence, fearfulness, and aggressiveness. Results highlighted strengths and limits of this TT that was devised to help shelter staff in matching dogs' personality and owners' expectations. Methodological constraints when working with sheltered dogs are unavoidable; however, the test proved to be overall feasible, reliable, and valid although further studies are needed to address the critical issues that emerged. © 2011 Elsevier Inc.

Laterality as an indicator of emotional stress in ewes and lambs during a separation test

We assessed motor laterality in sheep to explore species-specific brain hemi-field dominance and how this could be affected by genetic or developmental factors. Further, we investigated whether directionality and strength of laterality could be linked to emotional stress in ewes and their lambs during partial separation. Forty-three ewes and their singleton lambs were scored on the (left/right) direction of turn in a y-maze to rejoin a conspecific (laterality test). Further, their behavioural response (i.e. time spent near the fence, vocalisations, and activity level) during forced separation by an open-mesh fence was assessed (separation test). Individual laterality was recorded for 44.2 % ewes (significant right bias) and 81.4 % lambs (equally biased to the left and the right). There was no significant association in side bias between dams and offspring. The Chi-squared test revealed a significant population bias for both groups (p < 0.05). Evolutionary adaptive strategies or stimuli-related visual laterality may provide explanation for this decision-making process. Absolute strength of laterality (irrespective of side) was high (Kolmogorov–Smirnov test, dams: D = 0.2; p < 0.001; lambs: D = 0.36, p < 0.0001). The Wilcoxon test showed that lateralised lambs and dams spent significantly more time near each other during separation than non-lateralised animals (p < 0.05), and that lateralised dams were also more active than non-lateralised ones. Arguably, the lateralised animals showed a greater attraction to their pair because they were more disturbed and thus required greater reassurance. The data show that measures of laterality offer a potential novel non-invasive indicator of separation stress.

Test-retest variability in structural and functional parameters of glaucoma damage in the glaucoma imaging longitudinal study.

PURPOSE:

To determine the test-retest variability in perimetric, optic disc, and macular thickness parameters in a cohort of treated patients with established glaucoma.

PATIENTS AND METHODS:

In this cohort study, the authors analyzed the imaging studies and visual field tests at the baseline and 6-month visits of 162 eyes of 162 participant in the Glaucoma Imaging Longitudinal Study (GILS). They assessed the difference, expressed as the standard error of measurement, of Humphrey field analyzer II (HFA) Swedish Interactive Threshold Algorithm fast, Heidelberg retinal tomograph (HRT) II, and retinal thickness analyzer (RTA) parameters between the two visits and assumed that this difference was due to measurement variability, not pathologic change. A statistically significant change was defined as twice the standard error of measurement.

RESULTS:

In this cohort of treated glaucoma patients, it was found that statistically significant changes were 3.2 dB for mean deviation (MD), 2.2 for pattern standard deviation (PSD), 0.12 for cup shape measure, 0.26 mm for rim area, and 32.8 microm and 31.8 microm for superior and inferior macular thickness, respectively. On the basis of these values, it was estimated that the number of potential progression events detectable in this cohort by the parameters of MD, PSD, cup shape measure, rim area, superior macular thickness, and inferior macular thickness was 7.5, 6.0, 2.3, 5.7, 3.1, and 3.4, respectively.

CONCLUSIONS:

The variability of the measurements of MD, PSD, and rim area, relative to the range of possible values, is less than the variability of cup shape measure or macular thickness measurements. Therefore, the former measurements may be more useful global measurements for assessing progressive glaucoma damage.

Dark room provocative test and extent of angle closure: an anterior segment OCT study.

PURPOSE: To clarify the risk parameters measured by anterior segment optical coherence tomography (AS-OCT) for elevated intraocular pressures (IOP) provoked by the darkroom test and to provide recommendations for its clinical usage. METHODS: Subjects aged >40 years and whose peripheral anterior chambers were ≤1/4 corneal thickness were recruited. The anterior segment of the eye was imaged in sitting position and under both light and dark conditions and biometry was performed using anterior segment optical coherence tomography. The analyzed parameters were: (1) central anterior chamber depth (ACD); (2) anterior chamber width; (3) pupil diameter; (4) iris curvature; (5) lens thickness; and (6) number of meridians with closed angles (NCA). Then the darkroom test was performed and a positive provocative test result was defined as a rise in IOP ≥8 mm Hg after the test. Statistical analyses included: (1) the difference in parameters between positive and negative eyes; (2) the association between posttest IOP and the parameters; and (3) the difference in parameters between the 2 eyes in subjects with the asymmetric results. RESULTS: A total of 70 subjects were recruited. ACD (P=0.022), NCA in light (P<0.001), and NCA in dark (P<0.001) were different significantly between eyes with positive and negative results. There was a strong association between NCA in dark (r=0.755, P<0.001) and the posttest IOP. Among subjects with asymmetric results between the 2 eyes, the ACD was shallower and the lens thickness was larger in the positive eye. CONCLUSIONS: The posttest IOP is determined by the extent of functionally closed angles in the dark. The test may be useful in the early diagnosis of primary angle closure. At the same time, angle configuration should be evaluated to remove false positive result.

Pupil constriction can alter the accuracy of dark room provocative test.

BACKGROUND: Primary angle-closure glaucoma (PACG) is a major cause of visual morbidity in East Asia. Dark-room provocative test (DRPT) has been used to determine which narrow angles have the risk to develop angle closure. However, the accuracy of DRPT might be altered because that after emerging from the dark room, the configuration of the angle is affected by the light of the slit-lamp and the appositionally closed angle reopens. The aim of this study was to examine the pupillary diameter in different light conditions and use it as a parameter to assess the accuracy of dark-room provocative test. METHODS: Patients with suspected primary angle-closure glaucoma undergoing DRPT were recruited. The anterior chamber angle was examined by anterior segment optical coherence tomography under the following conditions: (1) in standard room illumination; (2) after short-term dark-adaptation and (3) after DRPT. Mean values of pupil size and numbers of appositionally closed angle under different conditions were compared. RESULTS: A total of 47 eyes of 47 patients were analyzed. The pupil size after DRPT was smaller than that after short-term dark-adaptation (P < 0.001) and smaller than that in standard room illumination (P = 0.026). The numbers of appositionally closed angles after short-term dark-adaptation were significantly larger than those after DRPT (P < 0.001). There was no significant difference between the numbers of appositionally closed angles in standard room illumination and after DRPT (P = 0.157). CONCLUSIONS: Constriction of pupil size immediately after prolonged dark room provocative test may lead to change in the angle configuration, which may lead to false negative results. We suggest a modified protocol of recording intraocular pressure immediately after DRPT and performing gonioscopy following short-term dark adaptation to improve the accuracy of angle closure assessment.