A UV laser ablation microprobe coupled to an ICPMS has been used to determine trace element concentrations in solids with a spatial resolution of S O microns and detection limits ranging from 52 pg/g for Ni to S O ng/g fortheREE,Th,andU.Experimentsdesignedtooptimize laser operating conditions show that pulse rates of 4 Hz p d u c e a steady state signal with less inter-element fractionation per unit time than higher pulse rates (10-20 Hz). Comparisons of laser microprobe analyses of garnets and pyroxenes using the NIST 610 and 612 glasfesascalibrationstandards,with proton microprobe, solutionICPMS,INMandXRFdatashownosignificant matrix effects. Laser microprobe analyses of the NIST 610 and 612 glasses have a p d o n and accuracy of 2-5%, and error analysis shows that counting statistics and the precision on the internal standard concentration accountsfor the analytical uncertainty.The NISTglasses appearto be useful calibration materialsfor trace element analysis of geological materials by laser microprobe.A laser ablation microprobe coupled with an inductively coupled plasma mass spectrometer (ICPMS) holds considerable promise for the rapid and precise in siru determination of trace element abundances in geological materials. Advantages of the technique include a spatial resolution of < 0.1 mm, sub-ppm detection limits for a variety of elements, and rapid analysis times (typically < 5 minutes per point analysis). Although relatively new, the technique has been applied to the determination of trace element zonation in silicate and carbonate minerals, natural and experimental crystal-melt partition,coefficients, whole rock analyses using pressed pellets and fused glasses, determination of Pb isotopic ages of zircons, and analysis of fluid inclusions (e.g., 1-10).As yet there is no consensus on analytical procedures such as laser operating conditions or calibration protocols, reflecting to some degree the variety of applications suitable for laser ablation analysis (11). This paper describes the analytical procedures and instrumental operating conditions currently used by our laboratory to malyse minerals and glasses for trace element abundances by laser ablation ICPMS. We also present new electron microprobe analyses for major element abundances in the NIST 610.612.614, and 616 glasses, o w best estimates for values of 28 trace elements in these glasses, and a comparison of laser microprobe analyses of a suite of mantle-derived garnets and pyroxenes with results by other techniques including proton m i c r o p r o b d solution ICPMS. INSTRUMENTATION Laser ablation systemThe laser ablation system and supporting software was designed by Drs. Simon Jackson and Henry Longerich of Memorial University (2,5). and was installed at Macquarie University in December, 1994. The laser is a Continuum Surelite 1-20 Q-switched Nd:YAG laser with a fundamental infrared (IR) wavelength at 1064 nm and a pulse width of 5-7 nsec. l b o frequency doubling crystals provide second and fourth harmonics in the visible (VIS, 532 nm) and ultrav...

Background: There is limited evidence on whether active case finding (ACF) among marginalised and vulnerable populations mitigates the financial burden during tuberculosis (TB) diagnosis. Objectives: To determine the effect of ACF among marginalised and vulnerable populations on prevalence and inequity of catastrophic costs due to TB diagnosis among TB-affected households when compared with passive case finding (PCF). Methods: In 18 randomly sampled ACF districts in India, during March 2016 to February 2017, we enrolled all new sputum-smear-positive TB patients detected through ACF and an equal number of randomly selected patients detected through PCF. Direct (medical and non-medical) and indirect costs due to TB diagnosis were collected through patient interviews at their residence. We defined costs due to TB diagnosis as ‘catastrophic’ if the total costs (direct and indirect) due to TB diagnosis exceeded 20% of annual pre-TB household income. We used concentration curves and indices to assess the extent of inequity. Results: When compared with patients detected through PCF (n = 231), ACF patients (n = 234) incurred lower median total costs (US$ 4.6 and 20.4, p < 0.001). The prevalence of catastrophic costs in ACF and PCF was 10.3 and 11.5% respectively. Adjusted analysis showed that patients detected through ACF had a 32% lower prevalence of catastrophic costs relative to PCF [adjusted prevalence ratio (95% CI): 0.68 (0.69, 0.97)]. The concentration indices (95% CI) for total costs in both ACF [−0.15 (−0.32, 0.11)] and PCF [−0.06 (−0.20, 0.08)] were not significantly different from the line of equality and each other. The concentration indices (95% CI) for catastrophic costs in both ACF [−0.60 (−0.81, –0.39)] and PCF [−0.58 (−0.78, –0.38)] were not significantly different from each other: however, both the curves had a significant distribution among the poorest quintiles. Conclusion: ACF among marginalised and vulnerable populations reduced total costs and prevalence of catastrophic costs due to TB diagnosis, but could not address inequity.

BackgroundAxshya SAMVAD is an active tuberculosis (TB) case finding (ACF) strategy under project Axshya (Axshya meaning ‘free of TB’ and SAMVAD meaning ‘conversation’) among marginalized and vulnerable populations in 285 districts of India.ObjectivesTo compare patient characteristics, health seeking, delays in diagnosis and treatment initiation among new sputum smear positive TB patients detected through ACF and passive case finding (PCF) under the national TB programme in marginalized and vulnerable populations between March 2016 and February 2017.MethodsThis observational analytic study was conducted in 18 randomly sampled Axshya districts. We enrolled all TB patients detected through ACF and an equal number of randomly selected patients detected through PCF in the same settings. Data on patient characteristics, health seeking and delays were collected through record review and patient interviews (at their residence). Delays included patient level delay (from eligibility for sputum examination to first contact with any health care provider (HCP)), health system level diagnosis delay (from contact with first HCP to TB diagnosis) and treatment initiation delays (from diagnosis to treatment initiation). Total delay was the sum of patient level, health system level diagnosis delay and treatment initiation delays.ResultsWe included 234 ACF-diagnosed and 231 PCF-diagnosed patients. When compared to PCF, ACF patients were relatively older (≥65 years, 14% versus 8%, p = 0.041), had no formal education (57% versus 36%, p<0.001), had lower monthly income per capita (median 13.1 versus 15.7 USD, p = 0.014), were more likely from rural areas (92% versus 81%, p<0.002) and residing far away from the sputum microscopy centres (more than 15 km, 24% versus 18%, p = 0.126). Fewer patients had history of significant loss of weight (68% versus 78%, p = 0.011) and sputum grade of 3+ (15% versus 21%, p = 0.060). Compared to PCF, HCP visits among ACF patients was significantly lower (median one versus two HCPs, p<0.001). ACF patients had significantly lower health system level diagnosis delay (median five versus 19 days, p = 0.008) and the association remained significant after adjusting for potential confounders. Patient level and total delays were not significantly different.ConclusionAxshya SAMVAD linked the most impoverished communities to TB care and resulted in reduction of health system level diagnosis delay.

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An MPIO creates a biomechanical environment conducive to healing of a neglected femoral neck nonunion in a child while simultaneously correcting an associated coxa vara. The procedure also seems to have a biological role in helping restore viability to a noncollapsed femoral head with avascular necrosis.