bluuebunny/crossref_metadata_2025_split huggingface dataset:
How Older Adults Maintain Lateral Balance While Walking on Narrowing Paths
Authors: Kazanski Meghan E. , Cusumano Joseph P. , Dingwell Jonathan B. 
Published: January 2024

ABSTRACTBackgroundOlder adults have difficulty maintaining side-to-side balance while navigating daily environments. Losing balance in such circumstances can lead to falls. We need to better understand how older adults adapt lateral balance to navigate environment-imposed task constraints.Research QuestionHow do older adults adjust mediolateral balance while walking along continually-narrowing paths, and what are the stability implications of these adjustments?MethodsEighteen older (71.6±6.0 years) and twenty younger (21.7±2.6 years) healthy adults traversed 25m-long paths that gradually narrowed from 45cm to 5cm. Participants switched onto an adjacent path when they chose. We quantified participants’ lateral center-of-mass dynamics and lateral Margins of Stability (MoSL) as paths narrowed. We quantified lateral Probability of Instability (PoIL) as the cumulative probability that participants would take a laterally unstable (MoSL<0) step as they walked. We also extracted these outcomes where participants switched paths.ResultsAs paths narrowed, all participants exhibited progressively smaller averageMoSLand increasingly largerPoIL. However, theirMoSLvariability was largest at both the narrowest and widest path sections. Older adults exhibited consistently both larger average and more variableMoSLacross path widths. Taken into account together, these resulted in either comparable or somewhat largerPoILas paths narrowed. Older adults left the narrowing paths sooner, on average, than younger. As they did so, older adults exhibited significantly larger average and more variableMoSL, but somewhat smallerPoILthan younger.SignificanceOur results directly challenge the predominant interpretation that larger averageMoSLas indicating “greater stability”, which we argue isinconsistentwith the principles underlying its derivation. In contrast, analyzing step-to-step gait dynamics, together with estimatingPoILallows one to properly quantify instability risk. Furthermore, the adaptive strategies uncovered using these methods suggest potential targets for future interventions to reduce falls in older adults.
Fluorescence lifetime imaging of sDarken as a tool for the evaluation of serotonin levels
Authors: Kubitschke Martin , Beck Vanessa , Masseck Olivia Andrea 
Published: January 2024

AbstractRecent advances in the development of genetically encoded biosensors have resulted in a variety of different neurotransmitter sensors for the precise measurement of the dynamics of neurotransmitters, neuromodulators, peptides and hormones in real time. However, intensity-based measurements of fluorescent biosensors are limited by their dependence on the expression level of the sensor, the intensity of the excitation light, and photobleaching overtime. Here, we show that the FLIM of sDarken (a GPCR-based genetically encoded sensor for serotonin) decreases with increasing serotonin concentrations. Different members of the sDarken family, with different affinities for serotonin, show concentration-dependent changes in fluorescence lifetime according to their dynamic range. We believe that this feature of sDarken is a value-adding complement to intensity-based information and may lead to a better understanding of serotonin dynamics in health and disease.
KATANIN-mediated microtubule severing is required for MTOC formation and function inMarchantia polymorpha
Authors: Attrill Sarah , Dolan Liam 
Published: January 2024

AbstractMicrotubule organising centres (MTOCs) are sites of localised microtubule nucleation in eukaryotic cells. Regulation of microtubule dynamics often involves KATANIN (KTN); a microtubule severing enzyme which cuts microtubules to generate new negative ends leading to catastrophic depolymerisation. InArabidopsis thaliana, KTN is required for the organisation of microtubules in the cell cortex, preprophase band, mitotic spindle and phragmoplast. However, as angiosperms lack MTOCs, the role of KTN in MTOC formation has yet to be studied in plants. Two unique MTOCs – the polar organisers – form on opposing sides of the prophase nucleus in liverworts. Here we show that KTN-mediated microtubule depolymerisation is required for thede novoformation of polar organisers in the liverwort,Marchantia polymorpha. In Mpktnmutants that lack KTN function, the formation, shape, number, and function of polar organisers is defective. This is in addition to defective microtubule organisation in the cell cortex, preprophase band, mitotic spindle, and phragmoplast. These data demonstrate that KTN-mediated microtubule dynamics are required for the formation of liverwort-specific MTOCs.
Multi-parametric assays capture sex- and environment-dependent modifiers of behavioral phenotypes in autism mouse models
Authors: Wahl Lucas , Karim Arun , Hassett Amy R. , van der Doe Max , Badura Aleksandra 
Published: January 2024

AbstractCurrent phenotyping approaches for murine autism models often focus on one selected behavioral feature, making the translation onto a spectrum of autistic characteristics in humans challenging. Furthermore, sex and environmental factors are rarely considered.Here, we aimed to capture the full spectrum of behavioral manifestations in three autism mouse models to develop a “behavioral fingerprint” that takes environmental and sex influences under consideration. To this end, we employed a wide range of classical standardized behavioral tests; and two multi-parametric behavioral assays: the Live Mouse Tracker and Motion Sequencing (MoSeq), on male and femaleShank2,Tsc1and Purkinje cell specific-Tsc1mutant mice raised in standard or enriched environments. Our aim was to integrate our high dimensional data into one single platform to classify differences in all experimental groups along dimensions with maximum discriminative power. Multi-parametric behavioral assays enabled far more accurate classification of experimental groups compared to classical tests, and dimensionality reduction analysis demonstrated significant additional gains in classification accuracy, highlighting the presence of sex, environmental and genotype differences in our experimental groups. Together, our results provide a complete phenotypic description of all tested groups, suggesting multi-parametric assays can capture the entire spectrum of the heterogenous phenotype in autism mouse models.
An iPSC-derived small intestine-on-chip with self-organizing epithelial, mesenchymal and neural cells
Authors: Moerkens Renée , Mooiweer Joram , Ramírez-Sánchez Aarón D. , Oelen Roy , Franke Lude , Wijmenga Cisca , Barrett Robert J. , Jonkers Iris H. , Withoff Sebo 
Published: January 2024

SummaryHuman induced pluripotent stem cell (hiPSC)-derived intestinal organoids are valuable tools for researching developmental biology and personalized therapies, but their closed topology and relative immature state limits their applications. Here we use organ-on-chip technology to develop a hiPSC-derived intestinal barrier with apical and basolateral access in a more physiological in vitro microenvironment. To replicate growth factor gradients along the crypt– villus axis, we locally exposed the cells to expansion and differentiation media. In these conditions, intestinal epithelial cells self-organize into villus-like folds with physiological barrier integrity and myofibroblast and neural subtypes emerge and form a layer in the bottom channel underneath the epithelial tissue. The growth factor gradients efficiently balance dividing and mature cell types and induce an intestinal epithelial composition, including absorptive and secretory lineages, resembling the composition of the human adult small intestine. The result is a well-characterized hiPSC-derived intestine-on-chip system that can facilitate personalized studies on physiological processes and therapy development in the human small intestine.
Laboratory evolution ofE. coliwith a natural vitamin B12analog reveals roles for cobamide uptake and adenosylation in methionine synthase-dependent growth
Authors: Mok Kenny C. , Hallberg Zachary F. , Procknow Rebecca R. , Taga Michiko E. 
Published: January 2024

AbstractBacteria encounter chemically similar nutrients in their environment that impact their growth in distinct ways. Among such nutrients are cobamides, the structurally diverse family of cofactors related to vitamin B12(cobalamin), which function as cofactors for diverse metabolic processes. Given that different environments contain varying abundances of different cobamides, bacteria are likely to encounter cobamides that enable them to grow robustly as well as those that do not function efficiently for their metabolism. Here, we performed a laboratory evolution of a cobamide-dependent strain ofEscherichia coliwith pseudocobalamin (pCbl), a cobamide thatE. coliuses less effectively than cobalamin for MetH-dependent methionine synthesis, to identify genetic adaptations that lead to improved growth with less-preferred cobamides. After propagating and sequencing nine independent lines and validating the results by constructing targeted mutations, we found that mutations that increase expression of the outer membrane cobamide transporter BtuB are beneficial during growth under cobamide-limiting conditions. Unexpectedly, we also found that overexpression of the cobamide adenosyltransferase BtuR confers a specific growth advantage in pCbl. Characterization of the latter phenotype revealed that BtuR and adenosylated cobamides contribute to optimal MetH-dependent growth. Together, these findings improve our understanding of how bacteria expand their cobamide-dependent metabolic potential.ImportanceIn nature, bacteria commonly experience fluctuations in the availability of required nutrients. Thus, their environment often contains nutrients that are insufficient in quantity or that function poorly in their metabolism. Cobamides, the vitamin B12family of cofactors, are ideal for investigating the influence of nutrient quality on bacterial growth. We performed a laboratory evolution experiment inE. coliwith a less-preferred cobamide to examine whether and how bacteria can improve their growth with less ideal nutrients. We found that overexpression of genes for cobamide uptake and modification are genetic adaptations that improve growth under these conditions. Given that cobamides are key shared metabolites in microbial communities, our results reveal insights into bacterial interactions and competition for nutrients.
Biophysical carbon concentrating mechanisms in land plants: insights from reaction-diffusion modeling
Authors: Kaste Joshua A.M. , Walker Berkley J. , Shachar-Hill Yair 
Published: January 2024

AbstractCarbon Concentrating Mechanisms (CCMs) have evolved numerous times in photosynthetic organisms. They elevate the concentration of CO2around the carbon-fixing enzyme rubisco, thereby increasing CO2assimilatory flux and reducing photorespiration. Biophysical CCMs, like the pyrenoid-based CCM ofChlamydomonas reinhardtiior carboxysome systems of cyanobacteria, are common in aquatic photosynthetic microbes, but in land plants appear only among the hornworts. To predict the likely efficiency of biophysical CCMs in C3 plants, we used spatially resolved reaction-diffusion models to predict rubisco saturation and light use efficiency. We find that the energy efficiency of adding individual CCM components to a C3 land plant is highly dependent on the permeability of lipid membranes to CO2, with values in the range reported in the literature that are higher than used in previous modeling studies resulting in low light use efficiency. Adding a complete pyrenoid-based CCM into the leaf cells of a C3 land plant is predicted to boost net CO2fixation, but at higher energetic costs than those incurred by photorespiratory losses without a CCM. Two notable exceptions are when substomatal CO2levels are as low as those found in land plants that already employ biochemical CCMs and when gas exchange is limited such as with hornworts, making the use of a biophysical CCM necessary to achieve net positive CO2fixation under atmospheric CO2levels. This provides an explanation for the uniqueness of hornworts’ CCM among land plants and evolution of pyrenoids multiple times.
Novel Pentafluorosulfanyl-containing Triclocarban Analogs selectively kill Gram-positive bacteria
Authors: Pormohammad Ali , Moradi Melika , Hommes Josefien W. , Pujol Eugènia , Naesens Lieve , Vázquez Santiago , Surewaard Bas G. J. , Zarei Mohammad , Vazquez-Carrera Manuel , Turner Raymond J. 
Published: January 2024

AbstractThe antibacterial and antibiofilm efficacy of our novel pentafluorosulfanyl-containing triclocarban analogs was explored against seven different Gram-positive and Gram-negative indicator strains. After initial screening, they had bactericidal and bacteriostatic activity against Gram-positive bacteria, especiallyStaphylococcus aureusandMRSA(methicillin–resistant staphylococcus aureus) in a very low concentration. Our results were compared with the most common antibiotic being used (Ciprofloxacin and Gentamycin); the novel components had significantly better antibacterial and antibiofilm activity in lower concentrations in comparison to the antibiotics. For instance, EBP-59minimum inhibitory concentration was < 0.0003 mM, while ciprofloxacin 0.08 mM. Further antibacterial activity of novel components was surveyed against 10 clinical antibiotic resistanceMRSAisolates. Again, novel components had significantly better antibacterial and antibiofilm activity in comparison with antibiotics. Mechanistic studies have revealed that none of these novel compounds exhibit any effect on the reduced thiol, disrupting iron sulfur clusters, or hydrogen peroxide pathways. Instead, their impact is attributed to the disruption of the Gram-positive bacterial cell membrane. Toxicity and safety testing on tissue cell culture showed promising results for the safety of components to the host.
Quantitative species delimitation, tests for gene flow, and migration models uncover complex, recent speciation in tree squirrels
Authors: Abreu Edson F. , Prado Joyce R. , Maldonado Jesús E. , Wilson Don E. , Percequillo Alexandre R. , Pavan Silvia E. 
Published: January 2024

AbstractAccurate estimates of species diversity are essential for all biodiversity research. Delimiting species and understanding the underlaying processes of speciation are also central components of systematic biology that outline our comprehension of the evolutionary mechanisms generating biodiversity. We obtained genomic data (Ultraconserved Elements and single nucleotide polymorphisms) for a widespread genus of South American tree squirrels (genusGuerlinguetus) to explore alternative hypotheses on species limits and to clarify recent and rapid speciation on continental-scale and dynamically evolving landscapes. Using a multilayered genomic approach that integrates fine-scale population genetic analyses with quantitative molecular species delimitation methods, we observed that (i) the most likely number of species withinGuerlinguetusis six, contrasting with both classic morphological revision and mitochondrial species delimitation; (ii) incongruencies in species relationships still persist, which might be a response to population migration and gene flow taking place in lowlands of eastern Amazonia; and (iii) effective migration surfaces detected important geographic barriers associated with the major Amazonian riverine systems and the mountain ranges of the Guiana shield. In conclusion, we uncovered unexpected species diversity of keystone mammals that are critical in tree-seed predation and dispersal in one of the most fragile and threated ecosystems of the world, the tropical rainforests of South America. Our results corroborate recent findings suggesting that much of the extant species-level diversity in Amazonia is young, dating back to the Quaternary, while also reinforcing long-established hypotheses on the role of rivers and climate-driven forest dynamics triggering Amazonian speciation.
Assessing White Matter Engagement in Brain Networks through Functional and Structural Connectivity Mapping
Authors: Li Muwei , Schilling Kurt G , Ding Zhaohua , Gore John C 
Published: January 2024

AbstractUnderstanding the intricate interplay between gray matter (GM) and white matter (WM) is crucial for deciphering the complex activities of the brain. While diffusion tensor imaging (DTI) has advanced the mapping of these structural pathways, the relationship between structural connectivity (SC) and functional connectivity (FC) remains inadequately understood. This study addresses the need for a more integrative approach by mapping the importance of the inter-GM functional link to its structural counterparts in WM. This mapping yields a spatial distribution of engagement that is not only highly reproducible but also aligns with direct structural, functional, and bioenergetic measures within WM, illustrating a notable interdependence between the function of GM and the characteristics of WM. Additionally, our research has uncovered a set of unique engagement modes through a clustering analysis of window-wise engagement maps, highlighting the dyanmic nature of the engagement. The engagement along with their temporal variations revealed significant differences across genders and age groups. These findings suggest the potential of WM engagement as a biomarker for neurological and cognitive conditions, offering a more nuanced understanding of individualized brain activity and connectivity patterns.
Inclusive, prompt and nonprompt
J/ψ
identification in proton-proton collisions at the Large Hadron Collider using machine learning
Authors: Prasad Suraj , Mallick Neelkamal , Sahoo Raghunath 
Published: January 2024

Studies related to J/ψ meson, a bound state of charm and anticharm quarks (cc¯), in heavy-ion collisions, provide genuine testing grounds for the theory of strong interaction, quantum chromodynamics. To better understand the underlying production mechanism, cold nuclear matter effects, and influence from the quark-gluon plasma, baseline measurements are also performed in proton-proton (pp) and proton-nucleus (p-A) collisions. The inclusive J/ψ measurement has contributions from both prompt and nonprompt productions. The prompt J/ψ is produced directly from the hadronic interactions or via feed down from directly produced higher charmonium states, whereas nonprompt J/ψ comes from the decay of beauty hadrons. In experiments, J/ψ is reconstructed through its electromagnetic decays to lepton pairs, in either e++e− or μ++μ− decay channels. In this work, for the first time, machine learning techniques are implemented to separate the prompt and nonprompt dimuon pairs from the background to obtain a better identification of the J/ψ signal for different production modes. The study has been performed in pp collisions at s=7 and 13 TeV simulated using 8. Machine learning models such as XGBoost and LightGBM are explored. The models could achieve up to 99% prediction accuracy. The transverse momentum (pT) and rapidity (y) differential measurements of inclusive, prompt, and nonprompt J/ψ, its multiplicity dependence, and the pT dependence of fraction of nonprompt J/ψ (fB) are shown. These results are compared to experimental findings wherever possible.

Published by the American Physical Society
2024
Smectic and Soap Bubble Optofluidic Lasers
Authors: Korenjak Zala , Humar Matjaž 
Published: January 2024

Soap bubbles are simple, yet very unique and marvelous objects. They exhibit a number of interesting properties such as beautiful interference colors and the formation of minimal surfaces. Various optical phenomena have been studied in soap films and bubbles, but so far they have not been employed as optical cavities. Here we demonstrate that dye doped soap or smectic liquid crystal bubbles can support whispering gallery mode lasing, which is observed in the spectrum as hundreds of regularly spaced peaks, resembling a frequency comb. The lasing enabled the measurement of size changes as small as 10 nm in a millimeter-sized, ∼100−nm-thick bubble. Bubble lasers were used as extremely sensitive electric field sensors with a smallest measurable electric field of 110  Vm−1 Hz−1/2. They also enable the measurement of pressures up to a 100 bar with a resolution of 1.5 Pa, resulting in a dynamic range of almost 107. By connecting the bubble to a reservoir of air, almost arbitrarily low pressure changes can be measured while maintaining an outstanding dynamic range. The demonstrated soap bubble lasers are a very unique type of microcavities which are one of the best electric field and pressure microsensors to date and could in the future also be employed to study thin films and cavity optomechanics.

Published by the American Physical Society
2024
Complex Structure of Molten FLiBe (2
LiF
–
BeF
2
) Examined by Experimental Neutron Scattering, X-Ray Scattering, and Deep-Neural-Network Based Molecular Dynamics
Authors: Fayfar Sean , Chahal Rajni , Williams Haley , Gardner D. Nathanael , Zheng Guiqiu , Sprouster David , Neuefeind Jörg C. , Olds Dan , Hwang Andrea , Mcfarlane Joanna , Gallagher Ryan C. , Asta Mark , Lam Stephen , Scarlat Raluca O. , Khaykovich Boris 
Published: January 2024

The use of molten salts as coolants, fuels, and tritium breeding blankets in the next generation of fission and fusion nuclear reactors benefits from furthering the characterization of the molecular structure of molten halide salts, paving the way to predictive capability of the chemical and thermophysical properties of molten salts. Due to its neutronic, chemical, and thermochemical properties, 2LiF-BeF2 is a candidate molten salt for several fusion- and fission-reactor designs. We performed neutron and x-ray total-scattering measurements to determine the atomic structure of liquid 2LiF-BeF2. We also performed and neural-network molecular-dynamics simulations to predict the structure obtained by neutron- and x-ray-diffraction experiments. The use of machine learning provides improvements to the efficiency in predicting the structure at a longer length scales than is achievable with simulations at significantly lower computational expense while retaining near accuracy. We found that the NNMD simulations accurately predicted the BeF42− oligomer formations seen in the experimental first-structure-factor peak. Our combination of high-resolution measurements with large-scale molecular dynamics provided an avenue to explore and experimentally verify the intermediate-range ordering beyond the first-nearest neighbor that has posed too many experimental and computational challenges in previous works. With a deeper understanding of the salt structure and ion ordering, the evolution of salt chemistry over the lifetime of a reactor can be better predicted, which is crucial to the licensing and operation of advanced fission and fusion reactors that employ molten salts. To this end, this work will serve as a reference for future studies of salt structure and macroscopic properties with and without the addition of solutes.

Published by the American Physical Society
2024