Agreement between BTS G-walk and GaitLab in spatiotemporal and pelvic angle measurements in active older adults
Background Aging impacts gait, a vital health indicator in older adults, reducing speed and increasing double support time, linked to falls and disability. The World Health Organization advises 150 min/week of moderate or 75 min/week of vigorous exercise, plus strength training, to sustain neuromuscular integrity and locomotor capacity associated with healthy gait patterns in older adults. While 3D motion capture is the gold standard for gait analysis, its cost and complexity limit use, boosting interest in portable inertial sensors like the BTS G-Walk. Yet, their accuracy in active older adults for spatiotemporal parameters and pelvic angles is underexplored, prompting this comparison with BTS GaitLab. Methods Fifty-nine active older adults (aged 65–87, mean 71.2 ± 5.5 years; eight men, 51 women) were assessed using BTS GaitLab (200 Hz cameras, 400 Hz force plates, Helen Hayes protocol, 18 markers) and BTS G-Walk (100 Hz, at L5) during four 10-meter walks at comfortable speed. Spatiotemporal parameters (cadence, speed, step length, stance/swing/support times) and pelvic angles (tilt, obliquity, rotation) were compared. Agreement used intraclass correlation coefficient (ICC), differences used paired t-tests, and variability used coefficient of variation (CV), with p < 0.05. Results Spatial parameters showed strong agreement: cadence (ICC = 0.98), speed (ICC = 0.96), step/stride length (ICC = 0.90–0.92), with no significant differences for cadence and speed (p > 0.05). Temporal parameters had weak agreement (e.g., stance time ICC = −0.18, swing time ICC = −0.54) and significant differences (p < 0.001). Pelvic angles had moderate agreement for tilt and obliquity (ICC = 0.48–0.78, p < 0.007), but low for rotation (ICC < 0.38, p > 0.038). Variability was high for double support time (CV 15.3–20.9%) and pelvic angles (CV > 27%). The sample (59) exceeds typical studies (7–23). Conclusions BTS G-Walk accurately measures spatial gait parameters in active older adults, ideal for quick clinical assessments where 3D systems are unavailable. However, its weak temporal parameter and pelvic rotation performance, possibly due to 100 Hz sampling, L5 placement, and algorithms, limits detailed analysis like stability. With a large sample and pelvic angle focus, this study supports G-Walk as a complementary tool in gerontology, while noting needs for improved temporal and angular precision.
Bittencourt et al. (2025) Agreement between BTS G-walk and GaitLab in spatiotemporal and pelvic angle measurements in active older adults. PeerJ 13:e20189 https://doi.org/10.7717/peerj.20189
Evidence of an upper entrainment limit for walking with fractal auditory stimuli
Background Variability exists in all biological signals, and in human gait research it has been found to be an indicator of neuromuscular system functioning. Detrended fluctuation analysis (DFA), a nonlinear method used to quantify the strength of long-range correlations in the temporal structure of stride-to-stride gait variability, has revealed gait differences in certain populations that are not observed with traditional linear measures like standard deviation. Previous research suggests that humans can adapt gait patterns to match different variability structures through sensory cues, such as auditory metronomes. However, the upper limits of adaptability and the strength of long-term correlations in gait variability remain unclear. Exploring these limits not only deepens our understanding of neuromuscular control mechanisms but could also inform the design of targeted interventions, such as rehabilitation strategies, to enhance motor control in clinical populations. The aim of this study was to investigate the possible upper limits of long-term correlations in stride-to-stride gait variability, characterized by the fractal scaling index (FSI) using DFA. Methods Fourteen healthy young adults (age 25 ± 3 years; seven females) completed seven treadmill walking trials at a fixed, self-selected speed. The first trial was uncued, and during the remaining six trials participants timed their steps to an auditory metronome with FSI ranging between 1.00 and 1.25. Gait FSI, velocity, stride time, cadence, and the time difference between heel contact and the associated metronome “tones” were calculated. Results Uncued gait FSI averaged 0.76 (±0.1). As the metronome FSI increased from 1.00 to 1.15, gait FSI approximated 1.00. Beyond 1.15 (metronome FSI values of 1.20 and 1.25), gait FSI dropped below 0.70, resembling uncued walking. Other gait measures remained unchanged. These findings suggest an upper gait FSI limit of approximately 1.00 during entrainment to metronome FSI values <1.20, beyond which adaptability diminishes. Conclusions This study establishes the upper entrainment limit for gait FSI during synchronization with fractal auditory stimuli, with implications for designing effective gait rehabilitation interventions targeting specific variability patterns.
Power et al. (2025) Evidence of an upper entrainment limit for walking with fractal auditory stimuli. PeerJ 13:e20176 https://doi.org/10.7717/peerj.20176
FastST: an efficient tool for inferring decomposition and directionality of microbial communities
Microbiomes play crucial roles in human health, disease development, and global ecosystem functioning. Understanding the origins, movements, and compositions of microbial communities is essential for unraveling the principles governing microbial ecology. Microbial source tracking (MST) approaches have emerged as valuable tools for quantifying the proportions of different microbial sources within target communities, enabling researchers to track transmissions between hosts and environments, identify similarities between microbiome samples, and determine sources of contamination in various settings. Current MST methods like SourceTracker2 and FEAST have advanced the field by employing Bayesian and expectation-maximization approaches, respectively, but are limited by computational inefficiency with high-dimensional data and inability to infer directionality in source-sink relationships. This study presents a novel computational framework for microbial source tracking called FastST. FastST infers the relative contributions of source environments to sink microbiomes while also determining directionality when source-sink relationships are not predefined. Through extensive simulation studies with varying numbers of sources and complexity, FastST demonstrates superior performance in both accuracy and computational efficiency compared to FEAST and SourceTracker2, maintaining consistent execution times even as the number of source environments increases. Furthermore, the proposed method achieved over 90% accuracy in directionality inference across all tested scenarios, even when multiple major sources are present, broadening its applicability in practical microbiome research and environmental monitoring. FastST and data simulation codes are publicly available at https://github.com/joungmin-choi/FastST.
Choi et al. (2025) FastST: an efficient tool for inferring decomposition and directionality of microbial communities. PeerJ 13:e20161 https://doi.org/10.7717/peerj.20161
Thermal-bias PCR: generation of amplicon libraries without degenerate primer interference
The polymerase chain reaction (PCR) has been used to amplify specific gene regions for many taxonomic studies and there have been substantial efforts to develop protocols that efficiently amplify target regions from a majority of mixed-template populations. Most protocols include the use of degenerate oligonucleotide primer pools, which contain mixed nucleotide sequences to improve priming from templates containing non-consensus sequence variations in their primer-binding sites. In this work, computational modeling and experimental measurements revealed that degenerate primers reduce efficiency well before a substantial product pool has been generated. It was also discovered that non-degenerate primers produced amplicons significantly better than their degenerate counterparts when amplifying either a consensus or a non-consensus target. Using quantitative, real-time PCR (qPCR) and data fitting as a guide, a new PCR protocol was developed that avoids the use of degenerate primers and allows for the stable amplification of targets containing mismatches to the targeting primers. This protocol involves the use of only two non-degenerate primers with no intermediate processing steps and it allows for the reproducible production of amplicon sequencing libraries that maintain the fractional representations of rare members.
Moore (2025) Thermal-bias PCR: generation of amplicon libraries without degenerate primer interference. PeerJ 13:e20241 https://doi.org/10.7717/peerj.20241
Dynamic effects of irrigation on photosynthesis and yield-related physiological characteristics in different glutinous wheat cultivars
Water scarcity critically constrains wheat production in North China, yet the irrigation responsiveness of novel glutinous wheat cultivars remains poorly quantified. This study systematically investigated the physiological mechanisms of common wheat Shimai 19 (SM19), partially glutinous SM19-P (Wx-B1 null), and fully glutinous SM19-N (triple null) under three irrigation regimes: rain-fed (W0), water-saving (W1: jointing irrigation), and conventional irrigation (W2: overwintering + jointing + flowering irrigations). Dynamic monitoring of flag leaf photosynthesis (Soil Plant Analysis Development (SPAD), stomatal conductance (Gs), transpiration rate (Tr), net photosynthetic rate (Pn)), antioxidant enzyme systems (superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) net photosynthetic rate (Pn), malondialdehyde (MDA)), grain starch synthase activities (granule-bound starch synthase (GBSS), soluble starch synthase (SSS), adenosine diphosphate glucose pyrophosphorylase (AGPase), starch branching enzyme (SBE)), and yield components revealed that: (1) SM19 achieved maximum photosynthetic capacity under W1 (Pn increased by 59.54% vs. W0 at 21 days post anthesis (DPA), p < 0.05) with optimal oxidative damage resistance (MDA reduced by 78.73% at 0 DPA), whereas SM19-P and SM19-N required W2 to reach photosynthetic peaks (Pn increased by 60.56% in SM19-P) and enzyme activity maxima (CAT increased by 66.67% in SM19-N). (2) Starch synthase activities peaked under water deficit (W0) early in grain-filling (≤14 DPA) but became tightly coupled to irrigation frequency thereafter. This was supported by a highly significant correlation between irrigation and final yield (r = 0.803, p < 0.01). The coordinated upregulation of AGPase and SSS (r = 0.726, p < 0.01) underpinned this response. The superior branched-starch accumulation in genotype SM19-N (+23%) was linked to its markedly higher SBE activity (r = 0.867, p < 0.01). (3) Yield optimization was genotype-specific: SM19 yielded highest under W1, while SM19-N peaked under W2. The study demonstrates that, unlike common wheat (SM19) which performs optimally under water-saving irrigation, the novel glutinous lines (SM19-P/SM19-N) require full irrigation to realize their yield potential, highlighting a critical trade-off between starch quality and drought adaptation. The key indicators identified—photosynthetic efficiency, antioxidant capacity, and starch metabolism—provide a theoretical foundation for developing future glutinous wheat varieties combining drought tolerance with high starch quality.
Li et al. (2025) Dynamic effects of irrigation on photosynthesis and yield-related physiological characteristics in different glutinous wheat cultivars. PeerJ 13:e20230 https://doi.org/10.7717/peerj.20230
Molecular epidemiology of carbapenem-resistant Escherichia coli in a tertiary hospital located in the Dabie Mountains region, China
Background The emergence of carbapenem-resistant Escherichia coli (CREc) strains poses a growing threat to global public health, presenting significant clinical and therapeutic challenges. Although extensive studies have been conducted in urban areas and high-incidence countries, data on the prevalence and molecular characteristics of CREc in rural regions remain limited, particularly in areas like the Dabie Mountains in China. This knowledge gap is critical because regional variations in resistance mechanisms may differ substantially. This study aims to address this gap by investigating the molecular epidemiology, genetic diversity, and resistance mechanisms of CREc in a tertiary hospital located in this under-researched region, providing crucial data for regional surveillance and informed public health interventions. Patients and methods Between 2018 and 2022, 33 CREc isolates were obtained from 33 patients at a tertiary hospital in the Dabie Mountains region of China. We performed a retrospective clinical analysis of the patients, followed by next-generation sequencing (NGS) and comprehensive bioinformatics analysis of all 33 CREc isolates. Additionally, phenotypic tests for carbapenemase and AmpC-type β-lactamase production were carried out. Results This study analyzed 33 CREc clinical isolates from a mountainous region hospital in China. The isolates predominantly originated from elderly patients (66.7% aged ≥ 60 years) with comorbidities (75.8%). Phenotypic analysis showed that 97.0% of isolates produced carbapenemases (n = 32), with the gene encoding New Delhi Metallo-β-lactamase (blaNDM) variants (n = 30) dominated by blaNDM-5 (n = 24) and a notable proportion of blaNDM-13 (n = 4). In addition to carbapenemase genes, the most prevalent resistance genes were those conferring resistance to sulfonamides (97.0%, 32/33) and aminoglycosides (93.9%, 31/33). Notably, 36.4% (n = 12) of isolates exhibited fosA3-mediated fosfomycin resistance, with universal co-carriage of extended-spectrum-β-lactamase (ESBL) genes. Genomic analysis identified 24 distinct sequence types (STs), with ST410 and ST692 being most prevalent. Molecular investigation localized blaNDM within diversified Tn125 derivatives and the gene encoding Klebsiella pneumoniae Carbapenemase (blaKPC-2) with truncated Tn6296 elements. Virulence factor screening detected 71 virulence genes, including highly prevalent adhesins (fimH, 84.8%) and hemolysins (hlyE, 97.0%). Plasmid profiling showed predominant IncFII (81.8%) and IncX (63.6%) replicon types. Conclusion This represents the first systematic investigation of CREc epidemiology in this understudied region. Our results demonstrate a high prevalence of carbapenem resistance mediated primarily by blaNDM-5, with co-occurrence of other resistance genes (fosA3) and virulence factors (fimH/hlyE/csgA).
Wang et al. (2025) Molecular epidemiology of carbapenem-resistant Escherichia coli in a tertiary hospital located in the Dabie Mountains region, China. PeerJ 13:e20188 https://doi.org/10.7717/peerj.20188
Food selection and feeding patterns in nectarivorous bats: Leptonycteris yerbabuenae and Glossophaga soricina
Sympatric species reduce competition for resources due to differences in one or more of their niche dimensions. Biotic interactions between pollinators and variations in the availability and quality of resources are important factors that determine food selection in bats. The nectarivorous species Leptonycteris yerbabuenae and Glossophaga soricina coexist temporarily in much of their distribution and depend on nectar to feed. These species have similar requirements but differ in the way they obtain food. The coexistence of bat species with similar requirements, such as L. yerbabuenae and G. soricina, suggests that these species have strategies for avoiding competition and maximizing their nectar consumption. However, it is unclear how these bat species select resources and adjust their visits to the available floral resources. We therefore analyzed nectar selection and feeding patterns in these two bat species under captive conditions. We conducted experiments in which we controlled resource type and its availability by offering the bats different artificial nectar solutions, while we removed interspecific interactions. These solutions differed in concentration and sugar type, and some were similar to the nectar offered by chiropterophilic plant species. The bat species presented differences in food selection; G. soricina fed mainly on resources similar to Ipomoea and sucrose sugar. In contrast, L. yerbabuenae preferred those resources similar to the nectar of Acanthocereus cacti. In addition, the timing of feeding for each solution also differed. These results suggest low levels of competition between species under abundant resources and low density of individuals; however, such conditions are not always found in nature, and patterns may change with increased food scarcity and a high density of competitors.
de Santiago-Hernández et al. (2025) Food selection and feeding patterns in nectarivorous bats: Leptonycteris yerbabuenae and Glossophaga soricina. PeerJ 13:e20164 https://doi.org/10.7717/peerj.20164
The expression of metastasis associated protein 2 in normal development and cancers: mechanism and clinical significance
Metastasis-associated protein 2 (MTA2), a master transcriptional regulator, through multiple target genes and interacting proteins, has been demonstrated to play a vital role in the regulation of proliferation, replication, apoptosis, autophagy, DNA damage repair, preimplantation, embryonic development and immune cell differentiation. Despite extensive research, the physiological role and pathogenic mechanisms of MTA2 remain poorly understood. Here, we mainly review in the current research the status of MTA2 and its implications in normal development and various tumor biology. Accumulating evidence suggests that MTA2 is frequently amplify in several types of cancers, closely associates with tumor cells migration and invasion, relates to the malignant characteristics and poor prognosis, which therefore has been considered as playing tumor oncogenic roles. Substantial evidence indicates that MTA2 functions by modulating downstream targets including cell growth, invasion as well as angiogenesis related genes. Confusingly, the proliferation effect of MTA2 remains elusive and even conflicting in the development of several solid tumors. Furthermore, we discuss the upstream regulation of MTA2 by transcription factors, microRNAs and lncRNAs in specific physiology and pathology conditions, which results in the abnormal MTA2 expression in various aspects of cancer. In this context, we summarize linked function of MTA2 directly to oncogenesis and might provide a significant avenue for the treatment of diseases. We hope that this review will help tumor molecular biologists further understand the molecular mechanism of MTA2 in normal development and cancer.
Liu et al. (2025) The expression of metastasis associated protein 2 in normal development and cancers: mechanism and clinical significance. PeerJ 13:e20107 https://doi.org/10.7717/peerj.20107
Changes in mercury content in oysters in relation to sediment and seston content in the Colombian Caribbean lagoons
Total mercury (Hg) was evaluated in the mangrove oyster Crassostrea rhizophorae, in sediments and seston from the Ciénaga Grande de Santa Marta (CGSM) and Cispatá Bay (BhC) in two climatic seasons (rainy and dry). Composite samples of sediments, seston and oysters in juvenile and adult ages were collected at six stations (three in each ecosystem) and Hg was quantified by atomic absorption spectrophotometry (Environmental Protection Agency (EPA) method 7473 PLTX-017). BhC had the highest Hg concentrations in sediment, seston and oysters compared to CGSM, with values close to the tolerable threshold for the ecosystem and associated biota (TEL) of 0.13 µg/g. Although at CGSM Hg was below the TEL in sediment and was considered safe in the oyster, significant bioconcentration was evident with the metal content in the seston, indicating a potential risk to the ecosystem and humans. The variables organic matter and temperature influenced metal availability in the sediment and seston, respectively; in contrast, they had no significant relationship in the oyster. In CGSM, higher Hg concentration was recorded in adult ages, while in BhC the highest accumulation occurred in juveniles, especially during the dry season. These findings underscore the importance of continuous Hg monitoring in both ecosystems. When assessed using the adapted Nemerow Pollution Index based on the provisional tolerable weekly intake (PTWI) of one µg Hg/kg body weight, although both sites presented a very high risk in terms of consumption, they are well below the most contaminated global hotspots over the past five decades. This study also highlights the relevance of oyster age in contamination assessments, as Hg accumulation patterns vary depending on environmental and climatic conditions.
Environmental Contamination and Remediation
Vélez-Mendoza et al. (2025) Changes in mercury content in oysters in relation to sediment and seston content in the Colombian Caribbean lagoons. PeerJ 13:e19868 https://doi.org/10.7717/peerj.19868
The profound impact of COVID-19 on college students’ physical fitness
Background This study expands existing research by examining longitudinal impacts of the COVID-19 pandemic on medical college students’ physical fitness. Methods A medical college in Wenzhou, was selected to examine the changes in physical fitness indicators among students from 2019 to 2021. Results While most students maintained normal weight status (85.2%), overweight/obese prevalence increased significantly (8.0% in 2019, 8.9% in 2020, and 10.1% in 2021). Among male students, 67.0% were classified within the passing range, while the majority of female students (55.0%) fell within the “good” grade category. In 2021, a significant decline was observed in the standing long jump, 50-m dash, and 1,000/800 m run (p < 0.05) across both genders. Conclusions The lingering effects of the COVID-19 pandemic have significantly contributed to increased weight gain among college students and a decline in their endurance running performance.
Sun et al. (2025) The profound impact of COVID-19 on college students’ physical fitness. PeerJ 13:e20293 https://doi.org/10.7717/peerj.20293