Toward low-loss mid-infrared Ga2O3-BaO-GeO2 optical fibers.

The development of efficient and compact photonic systems in support of mid-infrared integrated optics is currently facing several challenges. To date, most mid-infrared glass-based devices are employing fluoride or chalcogenide glasses (FCGs). Although the commercialization of FCGs-based optical devices has rapidly grown during the last decade, their development is rather cumbersome due to either poor crystallization and hygroscopicity resilience or poor mechanical-thermal properties of the FCGs. To overcome these issues, the parallel development of heavy-metal oxide optical fiber from the barium-germanium-gallium oxide vitreous system (BGG) has revealed a promising alternative. However, over 30 years of fiber fabrication optimization, the final missing step of drawing BGG fibers with acceptable losses for meters-long active and passive optical devices had not yet been reached. In this article, we first identify the three most important factors that prevent the fabrication of low-loss BGG fibers i.e., surface quality, volumic striae and glass thermal-darkening. Each of the three factors is then addressed in setting up a protocol enabling the fabrication of low-loss optical fibers from gallium-rich BGG glass compositions. Accordingly, to the best of our knowledge, we report the lowest losses ever measured in a BGG glass fiber i.e., down to 200 dB km-1 at 1350 nm.

Bedside colorimetric reagent dipstick in the diagnosis of meningitis in low- and middle-income countries: A prospective, international blinded comparison with laboratory analysis.

Background: Colorimetric reagent dipstick (CRD) for leukocyte esterase (LE) has shown potential for diagnosing and ruling out bacterial meningitis. Potential advantages over traditional cerebrospinal fluid (CSF) analysis include the small quantity of CSF required, rapid results, and easy interpretation. Our study aimed to determine whether clinicians in LMICs could accurately diagnose bacterial meningitis using CRD at the bedside. Methods: A convenience sample of 143 patients requiring lumbar puncture for possible meningitis were enrolled from 1 October 2018 to 31 December 2019 at three hospitals, one each in rural Burundi, the Democratic Republic of Congo, and Kenya. CSF was analyzed using CRD followed by traditional laboratory-based analysis by technicians blinded to bedside results. Results were analyzed for concordance rates, sensitivity/specificity, positive and negative predictive values and impact on clinical decision-making. Results: One hundred and one patients were included in the analysis. The prevalence of bacterial meningitis in the convenience sample was 35% (35/101) as defined by microscopy or positive Gram stain. Using a threshold of "any positivity" for LE on the CRD, bedside testing correctly identified 33/35 cases (sensitivity 94.3%) and had a NPV of 92%. When only a clearly positive (≥ "+" for LE) CRD criterion was used, sensitivity and NPV were 77.1% and 86.2%, respectively. Conclusion: Despite considerable promise, in our study, color reagent dipstick analysis of CSF did not perform well enough to rule out meningitis or screen samples for the need for microscopy. The development of a CSF-specific dipstick should be considered.

[Seroprevalence of leptospirosis in Puente Piedra, Lima, in 2006]. / Seroprevalencia de Leptospirosis en Puente Piedra, Lima en el año 2006.

Leptospirosis is a disease widely prevalent in tropical areas, but may also be present in urban areas. The present study aims to determine the seroprevalence of Leptospira in the district of Puente Piedra, where there have been cases of severe leptospirosis in recent years. We collected data related to risk factors associated with leptospirosis and blood samples from 250 participants, selected by random sampling. We found a high prevalence of risk factors in the population and using the microscopic agglutination test, antibodies were found in only 3 participants (1.2%).

Seroprevalencia de Leptospirosis en Puente Piedra, Lima en el año 2006 / Seroprevalence of Leptospirosis in Puente Piedra, Lima, in 2006

La leptospirosis es una enfermedad ampliamente prevalente en áreas tropicales, pero también se presenta en áreas urbanas. El presente estudio tiene como objetivo determinar la seroprevalencia para Leptospira en el distrito de Puente Piedra, donde se han presentado casos de leptospirosis severa en los últimos años. Se recolectaron datos relacionados a factores de riesgo asociados con leptospirosis y muestras de sangre de 250 participantes, seleccionados por un muestreo aleatorio. Se encontró una alta prevalencia de factores de riesgo en la población y, usando la prueba de aglutinación microscópica, anticuerpos circulantes contra Leptospira en solamente tres participantes (1,2 por ciento).

Leptospirosis is a disease widely prevalent in tropical areas, but may also be present in urban areas. The present study aims to determine the seroprevalence of Leptospira in the district of Puente Piedra, where there have been cases of severe leptospirosis in recent years. We collected data related to risk factors associated with leptospirosis and blood samples from 250 participants, selected by random sampling. We found a high prevalence of risk factors in the population and using the microscopic agglutination test, antibodies were found in only 3 participants (1.2 percent).