Microbial communities play a crucial role in ecosystem function through metabolic interactions. Genome-scale modeling is a promising method to understand these interactions. Flux balance analysis (FBA) is most often used to predict the flux through all reactions in a genome-scale model. However, the fluxes predicted by FBA depend on a user-defined cellular objective. Flux sampling is an alternative to FBA, as it provides the range of fluxes possible within a microbial community. Furthermore, flux sampling may capture additional heterogeneity across cells, especially when cells exhibit sub-maximal growth rates. In this study, we simulate the metabolism of microbial communities and compare the metabolic characteristics found with FBA and flux sampling. We find significant differences in the predicted metabolism with sampling, including increased cooperative interactions and pathway-specific changes in predicted flux. Our results suggest the importance of sampling-based and objective function-independent approaches to evaluate metabolic interactions and emphasize their utility in quantitatively studying interactions between cells and organisms.
Ultra-intense short-pulse lasers interacting with matter are capable of generating exceptionally bright secondary radiation sources. The short pulse duration (picoseconds to nanoseconds), small source size (sub-mm), and comparable high peak flux to conventional single particle sources make them an attractive source for radiography using a combination of particle species, known as multimodal imaging. Simultaneous x-ray and MeV neutron imaging of multi-material objects can yield unique advantages for material segmentation and identification within the full sample.
Chloride ions play vital roles in a variety of biological and environmental processes, making their accurate and efficient detection critical for both research and practical applications. In this perspective, we explore the recent advancements in the development of metal complex-based probes for chloride ion detection, with a focus on complexes involving transition and lanthanide metals. These probes offer remarkable selectivity and sensitivity, achieved through diverse mechanisms such as metal coordination, hydrogen bonding, electrostatic interactions, and halogen or chalcogen bonding.
Monitoring nuclear reactor operations is vital for nuclear safeguards as it ensures that reactors are in compliance with international legal agreements. Validating nuclear facilities and activities, including potential clandestine activities, is currently accomplished by using remotely sensed data from satellites and aircrafts and on-site sampling. However, these techniques are temporally-limited as sampling and interpretation of environmental releases frequently involve labor-intensive, on-site collections.
Microplastic (MP) pollution has reached the remotest areas of the globe, including the polar regions. In the Arctic Ocean, MPs have been detected in ice, snow, water, sediment, and biota, but their temporal dynamics remain poorly understood. To better understand the transport pathways and drivers of MP pollution in this fragile environment, this study aims to assess MPs (≥ 11 μm) in sediment trap samples collected at the HAUSGARTEN observatory (Fram Strait) from September 2019 to July 2021.
Motivation: Analysis of metabolic networks through extreme rays such as Extreme Pathways and Elementary Flux Modes has been shown to be effective for many applications. However, due to the combinatorial explosion of candidate vectors, their enumeration is currently limited to small- and medium-scale networks (typically less than 200 reactions). Partial enumeration of the extreme rays is shown to be possible, but either relies on generating them one-by-one or by implementing a sampling step in the enumeration algorithms.
