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BackgroundImplementation of new tuberculosis (TB) diagnostic strategies in resource-constrained settings is challenging. We measured the impact of solid and liquid mycobacterial cultures on treatment practices for patients undergoing TB evaluation in Kampala, Uganda.MethodsWe enrolled consecutive smear-negative, human immunodeficiency virus positive adults with cough of ⩾2 weeks from September 2009 to April 2010. Laboratory technicians performed mycobacterial cultures on solid and liquid media. We compared empiric treatment decisions with solid and liquid culture in terms of diagnostic yield and time to results, and assessed impact on patient management.ResultsOf 200 patients enrolled, 26 (13%) had culture-confirmed TB: 22 (85%) on solid culture alone, 2 (8%) on liquid culture alone, and 2 (8%) on both solid and liquid culture. Thirty-four patients received empiric anti-tuberculosis treatment, but only 10 (29%) were culture-positive. Median time to a positive result on solid culture was 92 days (interquartile range [IQR] 69-148) compared to 106 days (IQR 66-157) for liquid culture. No patients initiated treatment following a positive result on liquid culture.ConclusionThe introduction of mycobacterial culture did not influence care for patients undergoing evaluation for TB in Kampala, Uganda. Attention to contextual factors surrounding implementation is needed to ensure the effective introduction of new testing strategies in low-income countries.

The crude oil recovery process is frequently associated with the formation of stable emulsions due to factors such as turbulent flow in pipelines and the presence of surface-active substances that naturally occur in crude oil. These emulsions are undesirable for the petroleum industry because their destruction/treatment adds to the overall production cost and causes the loss of valuable amounts of crude oil. Therefore, it is essential, for economic and environmental reasons, to optimize the crude oil demulsification process. The effective treatment of crude oil emulsions requires understanding of the process and factors leading to their formation and stabilization. In this sense, suitable treatment methods and possible preventive measures to avoid their formation can be employed. The present study reviews recent oilfield emulsion types and the factors responsible for their formation and stabilization. The different demulsification techniques employed were then extensively examined. Demulsification techniques include mechanical, thermal, electrical, and chemical methods with different demulsification mechanisms affected by many factors such as emulsions type and properties, demulsifiers characteristics, presence of solids stabilized emulsions, etc. The demulsification efficiency depends on the operating parameters of the process, the economics involved, and the environmental impact, which are the main factors considered in selecting a suitable demulsification technique. Future research on the demulsification of crude oil emulsions should focus on real crude oil emulsions studies at a pilot scale level, the effect of aging on crude oil emulsions, the combination of multiple demulsification techniques and their synergistic effects, and the use of natural, ecofriendly demulsifiers.

The cumulative number of historical and recent power system outages substantiates the fact that further studies are necessary for an improved solution to the issue of voltage instability on the grid and the subsequent system collapse. Voltage collapse is a serious reliability issue which inhibits the objective of running a reliable and secure power system network. In this study, a new line stability index (NLSI_1) for predicting voltage collapse is presented. The new index considers a switching logic which is derived from the difference of voltage angle between the two load buses. The index is deployed for performance analysis using the 28-bus, 330-kV Nigeria National Grid (NNG). The simulation implemented in MATLAB shows that the index gives the same results as Line stability index (Lmn) and Fast Voltage Stability Index (FVSI) indices. The base case and the contingency scenarios were considered during the simulation. The base case analysis using the NNG values of all the three indices FVSI, Lmn, and NLSI_1 for simulation generates a value less than one for the entire lines which implies that the NNG is stable in this mode. The values of the three indices are almost the same, which confirms the accuracy of the novel index developed. The analysis for the contingency case reveals that the load bus 16 (Gombe) which has the lowest, maximum permissible reactive load of 139.5MVAR is the weakest; also power line 16-19 is identified as the critical line. The result of the simulation confirms that the accuracy was improved by using NLSI_1. [ABSTRACT FROM AUTHOR]

The capacity of trypanosome-infected cattle to mount an immune response to a simultaneous or subsequent challenge with other trypanosomes was investigated using various clones of Trypanosoma congolense and T. brucei. \n animals infected simultaneously with equal numbers of trypanosomes of two different clones, the variant specific antibody response to one clone was severely depressed while the response to the other was not affected. In cattle infected with one clone and then subsequently challenged with another, the variant-specific antibody response to the challenge clone was or was not severely depressed depending on the time interval between the two inoculations. These observations were consistent regardless of whether the clones of trypanosomes used were derived from the same or different species. The characteristics of these responses would suggest that the inability of Trypanosome-infected cattle to respond well to a simultaneous or subsequent challenge with other trypanosomes or other antigens may be due to antigenic competition. [ABSTRACT FROM AUTHOR]

The host cells of T. annulata can be infected with T. parva. With the superinfection of untreated T. annulata cultures it is not clear if only the few cells not carrying a schizont were susceptible to infection with T. parva or if cells with a T. annulata schizont also became infected with T. parva. In the latter case, T. parva parasites, while going through non-dividing stages (sporozoite, trophozoite, early schizont), may have been diluted out by the rapidly growing and dividing cells transformed by T. annulata. When the propagation of the cells infected by T. annulata was stopped by the schizonticidal treatment, a high infection rate with T. parva was achieved. However, eventually T. annulata-infected cells reappeared in the cultures and by 6 weeks appeared to be overgrowing the T. parva-infected cells. Nevertheless, for a period of 2-3 weeks the cultures consisted of cells, more than 99% of which were infected with T. parva. When inoculated into cattle at a dose of 6×10, these cells failed to initiate infection or induce immunity. In view of the fact that as few as 10 of these cells infected with T. annulata can induce infection and a serological response in cattle, these results indicate that the difference in the capacity of the two Theileria species to transfer infection is a property of the parasite rather than the host cell type which becomes infected. [ABSTRACT FROM AUTHOR]

Objective: To assess the prevalence of severe transaminitis precluding tuberculosis (TB) preventive therapy (TPT) initiation for people with HIV (PWH) in a high TB/HIV burden setting., Design/methods: We conducted a secondary analysis of data from a prospective cohort study of PWH with pre-antiretroviral therapy (ART) CD4 + counts 350 cells/μl or less undergoing systematic TB screening from two HIV clinics in Uganda. For this analysis, we excluded patients with culture-confirmed TB and patients without aspartate transaminase (AST) or alanine transaminase (ALT) levels measured within three months of enrollment. We compared the proportion of patients with any transaminitis (AST or ALT greater than one times the upper limit of normal ULN) and severe transaminitis (AST or ALT >3 times ULN) for patients screening negative for TB by symptoms and for those screening negative by C-reactive protein (CRP). We also assessed the proportion of patients with transaminitis by self-reported alcohol consumption., Results: Among 313 participants [158 (50%) women, median age 34 years (IQR 27-40)], 75 (24%) had any transaminitis and six (2%) had severe transaminitis. Of 32 of 313 (10%) who screened negative for TB by symptoms, none had severe transaminitis. In contrast, six-times more PWH screened negative for TB by CRP (194 of 313; 62%), of whom only four (2.1%) had severe transaminitis. Differences in the proportion with any and severe transaminitis according to alcohol consumption were not statistically significant., Conclusion: Prevalence of severe transaminitis was low among PWH without culture-confirmed TB in this setting, and is therefore, unlikely to be a major barrier to scaling-up TPT., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Mathematical competitions feature in most developed countries as a part of the secondary school experience, but to a lesser extent in developing countries. In this paper we investigate how widespread these competitions are in Africa, both historically as well as currently, focussing both on national Olympiads and on the participation of African countries in competitions beyond their borders, such as the continent-wide Pan African Mathematical Olympiad and the global International Mathematical Olympiad. Since we could not find a consolidated source of information on African competitions, we include many details and links, hoping that this paper will serve as a valuable starting point for future investigators. Next, we present some survey findings on the attitudes towards and experiences of mathematical competitions, both from the perspective of teachers in secondary schools as well as from secondary school students, and whether these experiences have served to improve or degrade their perceptions of mathematics in general. Among other results, we find that teachers view their students' participation in mathematics competitions as being important, with the biggest barrier to participation being that there are not enough competitions at appropriate levels available, and that students enjoy mathematics competitions and are more likely to pursue a STEM career because of them. Finally, we present some suggestions on how this research may be taken further, and on how the state of mathematical competition culture in Africa may be improved., (© FIZ Karlsruhe 2022.)

Point-of-care C-reactive protein (POC CRP) testing is a potential tuberculosis (TB) screening tool for people living with HIV (PLHIV). Unlike lab-based assays, POC assays do not routinely adjust CRP levels for hematocrit, potentially resulting in TB screening status misclassification. We compared the diagnostic accuracy of unadjusted and hematocrit-adjusted POC CRP for culture-confirmed TB among PLHIV with CD4 cell-count ≤350 cells/uL initiating antiretroviral therapy (ART) in Uganda. We prospectively enrolled consecutive adults, measured POC CRP (Boditech; normal <8 mg/L), collected two spot sputum specimens for comprehensive TB testing, and extracted pre-ART hematocrit from clinic records. Of the 605 PLHIV included, hematocrit-adjusted POC CRP had similar sensitivity (80% vs 81%, difference +1% [95% CI -3 to +5], P= 0.56) and specificity (71% vs 71%, difference 0% [95% CI -1 to +1], P= 0.56) for culture-confirmed TB, relative to unadjusted POC CRP. When used for TB screening, POC CRP may not require adjustment for hematocrit. However, larger studies may be required if differences close to the clinically meaningful threshold are to be detected., (Copyright © 2020 Elsevier Inc. All rights reserved.)

A 12-dose weekly regimen of rifapentine plus isoniazid (3HP) is recommended for the prevention of active tuberculosis (TB); however, it is unclear whether 3HP should be provided by directly observed therapy (DOT) or self-administered therapy (SAT). In addition, the introduction of patient informed choice between delivery modalities may have a positive impact on factors leading to treatment completion. The authors randomized 252 participants with HIV to a hypothetical scenario of providing preventive therapy by either DOT or an informed choice between DOT and SAT. Out of 104 participants who were randomized to a choice between DOT and SAT, 103 chose therapy by SAT. Participants rated their level of confidence and intention to complete therapy. Compared to those assigned to the DOT scenario, patients assigned to the choice scenario expressed greater confidence and intention to complete preventive therapy. Convenience and travel required to complete 3HP therapy were important factors in deciding between delivery modalities. Those assigned to DOT identified more barriers to completing therapy than those given a choice. Empowering patients to make informed decisions about how they receive TB preventive therapy may improve completion rates., Competing Interests: The authors have declared that no competing interests exist.