Spectroscopic investigation of molecular formation in laterally colliding laser-produced carbon plasmas: publisher's note.

This publisher's note corrects errors in Appl. Opt.58, 561 (2019)APOPAI0003-693510.1364/AO.58.000561.

Spectroscopic investigation of molecular formation in laterally colliding laser-produced carbon plasmas.

We report detailed spectroscopic investigation of carbon dimer production in the stagnation layer formed due to laterally colliding plasma plumes under vacuum and N2 ambience. Two spatially separated Nd:YAG laser pulses are used to generate plasma plumes in close proximity to a solid graphite target. A comparative optical emission spectroscopic study of a stagnation layer and a single carbon plasma plume is carried out in order to find the optimum experimental conditions for carbon dimer (C2) production. Significant enhancement in the C2 production is observed in the stagnation layer as compared to that observed in the single plume. Further, a substantial increase in carbon dimer formation is monitored by introducing N2 gas. Along with carbon dimer, carbon nitride (CN) band emission is also observed in the emission spectra. Spatiotemporal evolution of C2 and CN emission reveals that the yield of carbon dimer production is at a maximum close to the target surface, and decreases with an increase in time as well as spatial position. On the contrary, CN emission increases with the target distance. The dominant pathways for CN formation are suggested, and it is demonstrated that C2 acts as a precursor to CN formation. The above observation is correlated with cooling of ejected carbon species in the collisional regime and the estimated vibrational temperature of C2.

Challenges in the development of an immunochromatographic interferon-gamma test for diagnosis of pleural tuberculosis.

Existing diagnostic tests for pleural tuberculosis (TB) have inadequate accuracy and/or turnaround time. Interferon-gamma (IFNg) has been identified in many studies as a biomarker for pleural TB. Our objective was to develop a lateral flow, immunochromatographic test (ICT) based on this biomarker and to evaluate the test in a clinical cohort. Because IFNg is commonly present in non-TB pleural effusions in low amounts, a diagnostic IFNg-threshold was first defined with an enzyme-linked immunosorbent assay (ELISA) for IFNg in samples from 38 patients with a confirmed clinical diagnosis (cut-off of 300 pg/ml; 94% sensitivity and 93% specificity). The ICT was then designed; however, its achievable limit of detection (5000 pg/ml) was over 10-fold higher than that of the ELISA. After several iterations in development, the prototype ICT assay for IFNg had a sensitivity of 69% (95% confidence interval (CI): 50-83) and a specificity of 94% (95% CI: 81-99%) compared to ELISA on frozen samples. Evaluation of the prototype in a prospective clinical cohort (72 patients) on fresh pleural fluid samples, in comparison to a composite reference standard (including histopathological and microbiologic test results), showed that the prototype had 65% sensitivity (95% CI: 44-83) and 89% specificity (95% CI: 74-97). Discordant results were observed in 15% of samples if testing was repeated after one freezing and thawing step. Inter-rater variability was limited (3%; 1 out of 32). In conclusion, despite an iterative development and optimization process, the performance of the IFNg ICT remained lower than what could be expected from the published literature on IFNg as a biomarker in pleural fluid. Further improvements in the limit of detection of an ICT for IFNg, and possibly combination of IFNg with other biomarkers such as adenosine deaminase, are necessary for such a test to be of value in the evaluation of pleural tuberculosis.

Reinforcement of ball shaped MoS2 nanoparticles in epoxy resin.

The present work involves the synthesis of molybdenum disulfide (MoS2) nanoparticles by annealing the precursor obtained from simple reflux method. XRD, FESEM and HRTEM confirmed the formation of 2H-MoS2 with ball shaped particles, where some of them possess coalesced dumbbell morphology. The reinforcement of polysulphide modified epoxy resin (PSER) by MoS2 with varying amounts from 0.150 to 0.200 wt% provides unique combination of the improved thermal stability, tribological and mechanical properties. XRD studies indicate interaction between the sulphur containing nanoparticles and the epoxy resin. Maximum improvements in tensile strength (440%) and toughness (534%) are observed with ball shaped MoS2 nanoparticles (0.150 wt%)/PSER composite. Also the coefficient of friction and wear resistance show improvements of 60 and 78% respectively for 0.175 wt% loading in PSER compared to the neat resin matrix. Thermal stability is found to be improved maximum by 23 degrees C, when 5% weight loss is taken as a point of comparison. Similar studies on synthetic microcrystalline MoS2 filled PSER show that improvements in all these properties are very inferior.