Biodiesel and blends with petroleum diesel have shown their potential as renewable alternative fuels for engines, with additional benefits of low particulate matter and low sulfate emissions. In this paper we measure the soot volume fraction produced by three different methyl esters processed biodiesels (extracted from palm (PME), soy (SME) and coconut (CME)), and their blends with petroleum diesel, in a series of co-flow stabilized laminar pool flames, using laser induced-incandescence (LII) and laser extinction optical methods. The soot volume fraction measurement results show that all neat biodiesels produce only up to 33% of the total soot volume compared to pure diesel, and that the total soot volume correlates directly with the degree of unsaturation of the biodiesels. Blending leads to approximately linear behaviour of total soot volume, with a shift in slope with smaller sensitivity towards neat diesel.
Background
Outcomes of pediatric central nervous system (CNS) tumors in low‐ to middle‐income countries (LMIC) are poorer than their high‐income counterparts. Abandonment of therapy is increasingly recognized as a key contributor to this disparity, but has been poorly quantified. We performed a meta‐analysis to determine the magnitude of abandonment in pediatric CNS tumors in LMIC, and risk factors and interventions aimed at reducing this.
Patients and methods
We searched seven databases for pediatric CNS tumor cohorts followed up from diagnosis and treated in LMIC. All languages were included. Two reviewers independently selected articles and extracted data on abandonment rates (ARs) and predictors. The authors were contacted for additional information.
Results
Of 50 660 publications, 643 in five languages met criteria for full review; 131 met analysis inclusion criteria. ARs were not reported in the majority, and a small number were available from the authors. Available ARs ranged from 0% to 59%, from 38 studies (2497 children in 14 countries), and these were quantitatively analyzed. Lower‐middle‐income countries had higher ARs than upper‐middle‐income countries (27%, 95% confidence interval [CI] 20%–36% vs 9%, 95% CI 6%–14%, P < 0.0001), with significant heterogeneity within each (LMIC I2 = 78%, P < 0.00001, UMIC I2 = 85%, P < 0.00001). Common predictors for abandonment included distance to treatment centers, financial hardship, and prognostic misconceptions.
Conclusion
In LMICs, ARs are highest in lower‐MICs. However, the paucity of published data limits further evaluation. Given the increasing burden of pediatric CNS tumors in LMIC, addressing deficits in abandonment reporting is critical. Consistent reporting is needed for developing interventions to improve outcomes.
Planar two-dimensional two-color time-resolved laser-induced incandescence (2D-2C-TiRe-LII) is employed to investigate soot formation in a standard ethylene laminar diffusion flame. The time resolution of the 2D LII signal is realized by shifting the delay time of ICCD cameras. The two-color configuration is applied to measure the peak temperature T p of soot particles immediately after the laser pulse rather than using the energy balance to compute T p . The Sauter mean diameter D 32 and the corresponding distribution width parameter s of the measured soot particles is extracted by using an error minimization method. The method shows that a range of possible geometry mean particle diameters and corresponding distribution width parameters are also possible solutions, and further information on realizable particle size distribution widths is necessary to narrow down the extracted diameter.
EDITOR
Thomas KirchstetterCONTACT B. Tian
Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer. Within ALL, precursor B-cell disease predominates and now has survival >90%. Mature B-cell, or Burkitt leukemia/lymphoma, is distinct from ALL and requires short intensive chemotherapy and with the addition of Rituximab, survival rates of >95% are achieved. Its defining characteristic is MYC translocation at 8q24. Patients who have features of both ALL and Burkitt leukemia/lymphoma represent a rare subpopulation of ALL and present a diagnostic and treatment conundrum. We have performed a systematic review on the occurrence of and treatment of MYC positive precursor B-ALL, reported between 1980 and 2016. The review highlighted a lack of data to guide any consensus about how to treat this important group of children and focused research in this area is needed.
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