OBJECTIVES/GOALS: DR-TB care in South Africa includes decentralized treatment with shorter, all-oral regimens. Treatment guidelines direct regular clinical and laboratory evaluation to assess patient improvement. We therefore measured sputum collection frequency and follow-up time to assess fidelity to these guidelines in Gauteng Province, South Africa. METHODS/STUDY POPULATION: We included Rifampicin-resistant (RR) sputum specimens from the South African National Health Laboratory Service, which provides pathology services to 80% of the population, submitted between August 2022-September 2023. Patient data were obtained from a DR-TB registry and additional sputum specimen data were collected from follow-up laboratory worksheets. Follow-up spanned from first sputum collection date (baseline) to patient outcome date (e.g., completion, lost) or study closure date (if still on treatment). Monthly sputum submission rate was measured for those with ≥1 additional sputum submitted. We compared patient data by treatment site: at the specialized hospital vs. any other site, using Wilcoxon ranksum and χ2 tests. RESULTS/ANTICIPATED RESULTS: Baseline RR-TB specimens were available for 142 patients, of whom 28 (20%) had specimens submitted from the specialized hospital. Patients at the specialized hospital were older (median age 41 vs. 35.5 years, p=0.03), had higher baseline fluoroquinolone resistance (10% vs. 1%, p=0.01), and longer follow-up (median 5.2 vs. 3.5 months, p=0.01) compared to patients elsewhere. Further, 43 (30%) patients had ≥1 additional sputum submitted during follow-up. Among these, monthly sputum collection rates did not differ by site (0.3 vs. 0.3 sputum per month, p=0.89). We anticipate that increased sputum frequency will be associated with successful TB treatment outcomes based on preliminary findings. DISCUSSION/SIGNIFICANCE: These findings highlight ongoing challenges with routine laboratory follow-up according to DR-TB guidelines across treatment sites in South Africa. Future research is needed to determine reasons for low sputum collection rates, such as low patient adherence, variation in practice of healthcare workers, loss to follow-up, and clinical challenges.

We performed Monte Carlo and molecular dynamics simulations to investigate the interlayer structure of a uranyl-substituted smectite clay. Our clay model is a dioctahedral montmorillonite with negative charge sites in the octahedral sheet only. We simulated a wide range of interlayer water content (0 mg H2O/g clay — 260 mg H2O/g clay), but we were particularly interested in the two-layer hydrate that has been the focus of recent X-ray absorption experiments. Our simulation results for the two-layer hydrate of uranyl-montmorillonite yield a water content of 160 mg H2O/g clay and a layer spacing of 14.66 Å. Except at extremely low water content, uranyl cations are oriented nearly parallel to the surface normal in an outer-sphere complex. The first coordination shell consists of five water molecules with an average U-O distance of 2.45 Å, in good agreement with experimental data. At low water content, the cations can assume a perpendicular orientation to include surface oxygen atoms in the first coordination shell. Our molecular dynamics results show that ${\text{UO}}_2{\left({\text{H}}_2\text{O}\right)}_5^{2+}$ complexes translate within the clay pore through a jump diffusion process, and that first-shell water molecules are exchangeable and interchangeable.

Capacity evaluation has become a widely used assessment device in clinical practice to determine whether patients have the cognitive ability to render their own medical decisions. Such evaluations, which might be better thought of as “capacity challenges,” are generally thought of as benign tools used to facilitate care. This paper proposes that such challenges should be reconceptualized as significant medical interventions with their own set of risks, side effects, and potentially deleterious consequences. As a result, a cost–benefit analysis should be implemented prior to imposing such capacity challenges, and efforts should be made to minimize such challenges in situations where they are unlikely to alter the course of treatment.

In chemical process engineering, surrogate models of complex systems are often necessary for tasks of domain exploration, sensitivity analysis of the design parameters, and optimization. A suite of computational fluid dynamics (CFD) simulations geared toward chemical process equipment modeling has been developed and validated with experimental results from the literature. Various regression-based active learning strategies are explored with these CFD simulators in-the-loop under the constraints of a limited function evaluation budget. Specifically, five different sampling strategies and five regression techniques are compared, considering a set of four test cases of industrial significance and varying complexity. Gaussian process regression was observed to have a consistently good performance for these applications. The present quantitative study outlines the pros and cons of the different available techniques and highlights the best practices for their adoption. The test cases and tools are available with an open-source license to ensure reproducibility and engage the wider research community in contributing to both the CFD models and developing and benchmarking new improved algorithms tailored to this field.

There is a long history of exploitation of the South American river turtle Podocnemis expansa. Conservation efforts for this species started in the 1960s but best practices were not established, and population trends and the number of nesting females protected remained unknown. In 2014 we formed a working group to discuss conservation strategies and to compile population data across the species’ range. We analysed the spatial pattern of its abundance in relation to human and natural factors using multiple regression analyses. We found that > 85 conservation programmes are protecting 147,000 nesting females, primarily in Brazil. The top six sites harbour > 100,000 females and should be prioritized for conservation action. Abundance declines with latitude and we found no evidence of human pressure on current turtle abundance patterns. It is presently not possible to estimate the global population trend because the species is not monitored continuously across the Amazon basin. The number of females is increasing at some localities and decreasing at others. However, the current size of the protected population is well below the historical population size estimated from past levels of human consumption, which demonstrates the need for concerted global conservation action. The data and management recommendations compiled here provide the basis for a regional monitoring programme among South American countries.

Conventional electron microscopy during the last three decades has experienced tremendous developments, especially in equipment design and engineering, to become one of the most widely recognized and powerful tools for key research areas in materials science and nanotechnology. In this article, we discuss scanning ultrafast electron microscopy (S-UEM) as a new methodology for four-dimensional electron imaging of material surfaces. We also illustrate a few unique applications. By monitoring secondary electrons emitted from surfaces of photoactive materials, photo- and electron-impact-induced electrons and holes near surfaces, interfaces, and heterojunctions can be imaged with adequate spatial and temporal resolution. Charge separation, transport, and anisotropic motions as well as their dependence on carrier energies can be resolved. S-UEM is poised to directly image and visualize relevant interfacial dynamics in real space and time for emerging optoelectronic devices and help push their performance.

Growers of glyphosate-resistant crops apply micronutrients tank-mixed with glyphosate to save time and production costs. Therefore, effect of zinc (Zn), as Zn sulfate, on absorption, translocation, and efficacy of glyphosate on yellow nutsedge was investigated. Glyphosate at 850 g ae ha−1 provided 90% yellow nutsedge control at 5 wk after treatment (WAT). Presence of Zn at 1,000 ppmw in the glyphosate spray solution reduced yellow nutsedge control to 24 and 8%, 3 and 5 WAT, respectively. Yellow nutsedge control decreased with increasing Zn level (500 to 2,000 ppmw) in the spray solution. Yellow nutsedge treated with higher rates of Zn tank-mixed with glyphosate produced more tubers and tillers per plant than untreated plants. An abrupt decrease in absorption and translocation of 14C–glyphosate occurred between 500 and 1,000 ppmw Zn. The antagonistic effect of Zn on glyphosate depended mainly on reduced absorption and translocation of 14C–glyphosate within treated tissues. Less than 10% of applied 14C–glyphosate was absorbed when glyphosate was mixed with 1,000, 2,000, or 4,000 ppmw Zn as compared with 85% absorption for glyphosate alone. These treatments inhibited > 90% of 14C–glyphosate translocation out of the treated leaf and > 50% of tuber translocation relative to glyphosate alone. Results indicate that micronutrients containing Zn are not suitable for tank-mixing with glyphosate.