Browse Articles
Discover research articles across all indexed journals
Insights on the neurocognitive mechanisms underlying hippocampus-dependent memory impairment in COVID-19
Abstract COVID-19 has been linked to acute and long-term cognitive impairments, including memory and concentration deficits, as well as neuropsychiatric symptoms such as anxiety and depression. However, the neuropathophysiological mechanisms underlying these cognitive and affective changes remain poorly understood. Accumulating evidence points towards neuroinflammation as a potential driver of most acute and post-acute neurofunctional symptoms. In this study, we aimed to comprehensively characterize cognitive impairment associated with COVID-19 using a large online cohort of over 1400 participants, including individuals reporting a previous SARS-CoV-2 infection and individuals who had never been tested positive. Our cognitive test battery covered alertness, executive functions, and episodic long-term memory. Our results demonstrate a pronounced and selective impairment of individuals previously infected in a mnemonic discrimination task known to engage hippocampus-dependent pattern separation. This impairment remained statistically significant after controlling for potential confounding factors (i.e., age, gender, education, depressiveness, anxiety, and stress). This finding, derived indirectly from behavioral performance, suggests compromised hippocampal neurogenesis following infection, which may contribute to COVID-related memory deficits. Our study has important implications for understanding the neurofunctional consequences of COVID-19 and highlights the potential significance of neuroinflammation in the manifestation of cognitive impairments.
Evaluating language model embeddings for Parkinson’s disease cohort harmonization using a novel manually curated variable mapping schema
Abstract Data Harmonization is an important yet time-consuming process. With the recent popularity of applications using Language Models (LMs) due to their high capabilities in text understanding, we investigated whether LMs could facilitate data harmonization for clinical use cases. To evaluate this, we created PASSIONATE, a novel Parkinson’s disease (PD) variable mapping schema as a ground truth source for pairwise cohort harmonization using LLMs. Additionally, we extended our investigation using an existing Alzheimer’s disease (AD) CDM. We computed text embeddings based on two language models to perform automated cohort harmonization for both AD and PD. We additionally compared the results to a baseline method using fuzzy string matching to determine the degree to which the semantic capabilities of language models can be utilized for automated cohort harmonization. We found that mappings based on text embeddings performed significantly better than those generated by fuzzy string matching, reaching an average accuracy of over 80% for almost all tested PD cohorts. When extended to a further neighborhood of possible matches, the accuracy could be improved to up to 96%. Our results suggest that language models can be used for automated harmonization with a high accuracy that can potentially be improved in the future by applying domain-trained models.
Elements pollution and ecological risk assessment of coastal sediments along the Nile Delta
Abstract The Nile Delta coastal area surface sediments were evaluated for twenty-five elements. Inductively coupled plasma-mass spectroscopy (ICP-MS method) was used to analyze the digested solutions, previously filtered using discrete 0.2 μm PTFE syringe filters according to USEPA protocols. Potentially toxic elements (PTEs) and pollution levels were estimated using several indices. Pollution guides such as the enrichment factor (EF), contamination degree (C d), geoaccumulation index (I geo), and pollution load index (PLI) are mainly determined by actually toxic elements such as Cr, Co, Cd, Hg and Pb, while Principal component analysis (PCA), concerned with the distribution of all elements in sediment to determine the sources of elements. The following is the order of the EF values: Mn < Cu < Zn < Ni < Pb < Cr. The areas under investigation showed no pollution with Cr, Cu, Mn, Ni, Pb, or Zn, as indicated by their (I geo ≤0) values and C d (< 1.5). Significant connections between Mn, Fe, Cr, Co, and Ni values were observed, indicating comparable origins. In the current study, the children’s Hazard Quotient (HQ) results for the dermal exposure pathway are low, but adult values are 3–4 times higher. The chronic daily intake (CDI Dermal) and carcinogenic risk (CR Dermal) through dermal absorption were also investigated.
Petrogenesis and tectonic evolution of tourmaline- bearing leucogranites, Sikait area, South Eastern Desert of Egypt utilizing mineralogical and bulk rock analysis
Abstract The current research discuss in detail the tourmaline distribution in Sikait leucogranites in order to deduce its genesis and type. We conduct new detailed geological, petrographical, mineralogical, and geochemical examinations to understand the Arabian Nubian Shield development by investigation of such the examined leucogranites. Tourmaline occurs as disseminated or cluster nodular within coarse-grained leucogranites. Geochemically, the examined leucogranites have high contents of SiO2 (69.44–75.87 wt%), and total alkalis (mean > 7) with low mean CaO (0.4 wt%), Fe2O3 (1.93 wt%), and Mg# (14.59) values. They share features of calc-alkaline, strongly peraluminous (A/CNK > 1.1), with high contents of Zn (av. 266.68 ppm), Pb (av. 29.13 ppm), Rb/Sr (av. 22), Al2O3/TiO2 (av. 832.6), FeO/MgO (av. 12.24). They are remarkably enriched in semi-volatile elements (Pb = 12–235 ppm), and LILEs (Rb = 192–679 ppm) relative to HFSEs (e.g. Zr, U and Nb) with notable strong Ba, Sr and Ti negative anomalies. They are depleted in ∑REEs (av. 19.1 ppm) and reveal parallel, uniform patterns slightly notable depletion of HREEs in comparison with LREEs. They reveal extreme pronounced Eu (av. Eu/Eu*= 0.02) negative and Ce/Ce* (0.76–1.12) positive anomalies. The examined rocks have prominent tetrad effect (M-type) as indicated by Irber and Lambda methods. Based up on conventional geochemical diagrams, the examined rocks are post-collisional S-type granites derived by partial degree of the clay-rich pelite rocks melting followed by extreme fractional crystallization processes during post-collisional extension episode at temperatures (663 –786 °C) based on saturation temperature of zircon. The investigated tourmaline nodules are of alkali group and foitite end-member.
Cerebrospinal fluid protein profiling of inflammatory and neurobiological markers in Lyme neuroborreliosis
Abstract Lyme neuroborreliosis (LNB) is the most common form of disseminated Lyme borreliosis in Europe and North America. There are limitations in existing LNB diagnostics and a lack of reliable objective markers for disease-course. Here, extensive protein profiling with two panels of 184 proteins, was done in the search for new clinically useful diagnostic and prognostic candidate biomarkers. Cerebrospinal fluid (CSF) was collected from patients with definite LNB (n = 13) at the time of diagnosis before initiating antibiotic treatment, and at a follow-up one month later. When symptoms were evaluated at a six-month follow-up, six patients had recovered with no persistent symptoms (NPS), and seven experienced delayed recovery with persistent post-treatment symptoms (PS). Orthopedic patients (n = 60) served as controls. With the panels used, no protein biomarkers able to differentiate between PS and NPS were identified. However, from a diagnostic perspective, we identified multiple proteins that were differentially expressed between LNB and controls. The majority of them were downregulated following antibiotic treatment, at the one-month follow-up. IL10, TNF, and CCL8 were considered examples of potentially useful candidate biomarkers in both the early diagnostics and in monitoring of treatment response. These markers merit further investigation to understand their utility in relation to other neurological manifestations.
Impacts of commercial bile acids on growth performance, immune responses and expression genes of lipid metabolism in Nile tilapia fingerlings Oreochromis niloticus
Abstract The current investigation evaluated the impact of the dietary addition of commercial bile acids (BAs) on growth, nutrient assimilation, immunity, antioxidant status, intestinal and hepatic histomorphometry, and gene expression of lipid metabolism in Nile tilapia (Oreochromis niloticus). In a study conducted for seventy days, 180 healthy fingerlings weighing 9 ± 0.5 g were divided into 18 hapas measuring 0.7 × 0.7 × 1.0 m. The fish were fed on six meals enriched with varied amounts of BAs: 0.0 (D1), 0.1 (D2), 0.2 (D3), 0.3 (D4), 0.4 (D5), and 0.5 (D6) g/kg diet. Nile tilapia fed the D3 diet exhibited significantly enhanced growth performance, with a specific growth rate of 1.89%/day and had the greatest feed conversion ratio (1.25), protein productive value, and energy utilization (33.28%). Fish fed the D3 exhibited significantly the highest crude protein content (64.50%). Energy content varied significantly, with D1 showing the lowest value (533.34 Kcal/100 g) and D3 the highest (604.27 Kcal/100 g). D3 improved biochemical indicators, immunological parameters, and digestive enzymes of O. niloticus. Histological analysis revealed notable liver and intestinal integrity enhancements among fish receiving BA-enriched diets, especially D3. Additionally, gene expression related to lipid metabolism in liver, peritoneal fat, and muscle tissues was upregulated in the treatment groups, especially 0.2 g/kg BAs compared to the control group. Results illustrate significant modulation of lipid metabolism gene expression parameters (Adipose triglyceride lipase; ATGL, Hormone-sensitive lipase; HSL, Peroxisome proliferator-activated receptor α; PPARα, Fatty acid synthase; FAS) by BAs treatments and were upregulated in BA-fed groups (D2–D6). Conversely, Carnitine palmitoyl transferase 1; CPT-1and Insulin-like growth factor-II; Igf-II expression declined, particularly when the BAs dose was increased. Accordingly, dietary 0.2 g/kg BAs supplementation positively influences on physiological, biochemical parameters, and lipid metabolic of Nile tilapia, making it a promising feed additive for aquaculture.
Optimized frequency stabilization in hybrid renewable power grids with integrated energy storage systems using a modified fuzzy-TID controller
Abstract This article presents several innovative methods to mitigate frequency deviations in hybrid renewable power grids (HRPGs) with high penetration of renewable energy sources (RESs). Two models of the HRPGs are considered: the first model is a two-area power grid that combines three conventional power plants and two RESs in each area, while the second model is the IEEE 39-bus system. The tie-line is connected in series with a unified power flow controller (UPFC). The first method introduces an approach in the secondary control loop (SCL), where a fuzzy logic controller is cascaded with an Integral-Tilt-Derivative (I-TD) controller (Fuzzy I-TD). Additionally, the performance of the Fuzzy I-TD controller is compared with other approaches, such as Fuzzy Proportional-Integral-Derivative (Fuzzy-PID) and Fuzzy Integral-Proportional-Derivative (Fuzzy I-PD). The second strategy integrates the Fuzzy I-TD controller in the SCL along with controlled energy storage systems (ESSs), such as plug-in electric vehicles (PEVs). The parameters of the strategies are optimized using a recent metaheuristic algorithm known as the Sea Horse Optimizer (SHO) under different operating conditions. A comprehensive investigation is conducted to validate the effectiveness of the Fuzzy I-TD controller and the Fuzzy I-TD controller with PEVs in HRPGs. The Fuzzy I-TD controller significantly reduces frequency and tie-line deviations in the SCL by 82.7% and 97.01%, respectively, when compared to the Fuzzy I-PD and Fuzzy-PID controllers. Moreover, the Fuzzy I-TD with PEVs reduces frequency fluctuations by 40% compared to the Fuzzy I-TD alone in the SCL. The results demonstrate that the presented strategy is efficient and effective for HRPGs.
Attenuated behavioral interpersonal synchrony in autistic adults is not explained by perception of timing
Abstract Attenuated interpersonal synchrony (IPS) has been shown between autistic individuals and their interaction partners; however, the mechanisms of this attenuation remain unclear. One possibility could lie in perceiving the timing of others’ behaviors. The present study aimed to relate the behavioral production of IPS with the perception of temporal dynamics of social interactions and event timing perception in autistic and non-autistic adults. Autistic and non-autistic participants engaged in naturalistic conversations with a non-autistic stranger, who was naïve to the participant’s diagnostic status. Behavioral IPS was computed using automatic video-based analysis. Participants reported their experiences of perceived IPS with the partner, as a measure of the perceived temporal dynamics of the social interaction. A perceptual simultaneity task measured the perception of event timing in a nonsocial context. Bayesian linear mixed models were used to evaluate the effects of perceived IPS ratings and simultaneity thresholds on behavioral IPS. Expectedly, behavioral IPS was reduced for dyads including an autistic adult. Neither perceived IPS ratings, nor simultaneity thresholds, were associated with reduced behavioral IPS for dyads with or without an autistic adult. These findings hint that attenuated behavioral IPS may not result from atypical perceived timing of others’ behaviors or event timing perception.
Air temperature estimation and modeling using data driven techniques based on best subset regression model in Egypt
Abstract Air temperature plays a critical role in estimating agricultural water requirements, hydrological processes, and the climate change impacts. This study aims to identify the most accurate forecasting model for daily minimum (T min ) and maximum (T max ) temperatures in a semi-arid environment. Five machine learning models—linear regression (LR), additive regression (AR), support vector machine (SVM), random subspace (RSS), and M5 pruned (M5P)—were compared for T max and T min forecasting in Gharbia Governorate, Egypt, using data from 1979 to 2014. The dataset was divided into 75% for training and 25% for testing. Model input combinations were selected based on best subset regression analysis, result shows the best combination was T min(t−1) , T min(t−3) , T min(t−4) , T min(t−5) , T min(t−6) , T min(t−7) , T min(t−8) and T max (t−1) , T max (t−2) , T max (t−3) , T max (t−4) , T max (t−5) , T max (t−6) , T max (t−8) for daily minimum maximum air temperature forecasting, respectively. The M5P model outperformed the other models in predicting both T max and T min . For T min , the M5P model achieved the lowest root mean square error (RMSE) of 2.4881 °C, mean absolute error (MAE) of 1.9515, and relative absolute error (RAE) of 40.4887, alongside the highest Nash-Sutcliffe efficiency (NSE) of 0.8048 and Pearson correlation coefficient (PCC) of 0.8971. In T max forecasting, M5P showed a lower RMSE of 2.7696 °C, MAE of 1.9867, RAE of 29.5440, and higher NSE of 0.8720 and R² of 0.8720. These results suggest that M5P is a robust and precise model for temperature forecasting, significantly outperforming LR, AR, RSS, and SVM models. The findings provide valuable insights for improving decision-making in areas such as water resource management, irrigation systems, and agricultural productivity, offering a reliable tool for enhancing operational efficiency and sustainability in semi-arid regions. The Friedman ANOVA and Dunn’s test confirm significant differences among temperature forecasting models. Additive Regression overestimates, while Linear Regression and SVM align closely with actual values. Random Subspace and M5P exhibit high variability, with SVM differing significantly. For maximum temperature, Random Subspace and M5P perform similarly, while SVM remains distinct.
Investigating the metastability of amorphous calcium carbonate by droplet microfluidics experiments using machine learning
Abstract Amorphous calcium carbonate (ACC) plays an important role in the crystallization pathways of calcite and its polymorphs influencing many natural and anthropogenic processes, such as carbon sequestration. Characterizing the dissolution rate of ACC in presence of additives of contaminants in favor of crystalline phases is challenging as such reactions occur readily in bulk solution. Droplet microfluidics offers a solution by confining ACC within a droplet, enabling a quantification of the transformation rate of ACC into crystalline phases. However, accurate quantification of this transformation requires analyzing more than thousands of droplets identifying the different polymorphs of calcium carbonate during an experiment, which is labor-intensive. Here we develop a visual-based machine learning method, combining cascading U-Net and K-Means clustering, to allow efficient analysis of droplet microfluidics experiment results. Using our method, we accurately inspect 11,288 droplets over 6 hours of experimental time to identify the polymorphs, using a CPU core in a laptop for only 42 minutes. This is achieved with manual labeling of 11 experimental microscopy images before augmentations. From our analyses the transformation rate of ACC into its crystalline phases can be inferred. The transformation rate indicates an increasing stability of the ACC phase in confinement. Our method is generalizable and can be applied to different setups of droplet microfluidics experiments, facilitating efficient experimentation and analysis of complex crystallization processes.
Volumetric predictors for shunt-dependency in pediatric posterior fossa tumors
Abstract Posterior fossa (PF) tumors are the most common neoplastic entity in pediatric neurosurgery. Children suffering from PF tumors regularly present with hydrocephalus and CSF diversion is a crucial point of treatment. There is an ongoing debate about external ventricular drainage (EVD) management before surgery and its influence on ongoing hydrocephalus treatment afterwards. Beyond onco-surgical aspects, the prevention of shunt-dependency is an important goal in posterior fossa surgery. Various predictors for shunt-dependency after posterior fossa surgery in children have been suggested. Because these predictors may only apply to small subsets of children, and their reliability has been questioned, we evaluated a straightforward, potentially automated, and unbiased method for shunt prediction. In this retrospective radiomic study we analyzed 60 pediatric patients with posterior fossa tumors. Exclusion criteria were age under two years, missing MRI data, tumor location non-exclusive to the PF, traumatic brain injury and less than 6 months follow-up. Ultimately, 36 children met the inclusion criteria. We performed a volumetric assessment of various skull and brain compartments before and after surgery focused on ventricle-brain ratio (VBR). We dichotomized for potential predictors and performed ROC analyses. We evaluated the prognostic parameters for shunt dependency, including supratentorial transependymal edema and VBR, as well as pre- and postoperative radiomic measurements as early prognostic tools. The cutoff in ventricle volume for CSF diversion was 60.9 ml (AUC 0.788, p = 0.001). The radiomic-based prediction of shunt dependency with VBR-scoring showed an AUC of 0.783. Postoperative reduction in ventricle size, depicted by the deltaVBR scoring, showed an AUC of 0.719 in predicting shunt-free survival. Perioperative CSF diversion did correlate with postoperative persistent HCP, whereas the odd’s ratio for shunting was decreased, but not significantly lower, when CSF diversion was undertaken perioperatively (AUC = 0.618, OR = 0.273, CI = 0.029–2.577). Ventricle-brain ratio may be a potential predictor for the necessity of CSF diversion. In our cohort, radiomic predictors performed better than hydrocephalus categorization, modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) or transependymal edema alone. VBR pre- and deltaVBR postoperatively may be potential tools to predict the need for shunting in pediatric posterior fossa tumor patients. The decision for pre- or intraoperative CSF diversion showed no correlation and no influence on persistent hydrocephalus.
Quantitative comparison of a novel swept-source optical coherence tomography angiography device with three established systems
Abstract Optical Coherence Tomography Angiography (OCTA) has become an essential non-invasive imaging technique for high-resolution visualization of retinal microvasculature. This study evaluates the performance of a novel Swept-Source OCTA device, Intalight DREAM, compared to established systems: Heidelberg Spectralis, Topcon Triton, and Zeiss Cirrus. We assessed acquisition time and microvascular parameters in the superficial (SCP) and deep (DCP) capillary plexuses using the OCTA Vascular Analyser algorithm for standardized image analysis across devices on 30 eyes from 15 healthy participants. In the SCP, DREAM demonstrated a higher median vessel length (47 μm) and greater fractal dimension (mean: 1.999) than the other devices, indicating enhanced continuity and network complexity. In the DCP, DREAM showed a smaller foveal avascular zone (median: 0.339 mm2) compared to Spectralis (0.51 mm2), Triton (0.5935 mm2), and Cirrus (0.9145 mm2), along with a smaller vessel diameter (median: 23 μm) compared to Triton and Cirrus. With a median imaging time of 9.1 s, DREAM was significantly faster than the Spectralis system (23.3 s) while providing largely comparable image quality, enhancing patient comfort, and potentially minimizing motion artifacts. These findings suggest that DREAM OCT is a promising tool for deep retinal imaging, with strong potential for clinical application and research.
Evaluating gene expression and biomarkers for mastitis resistance in Barki sheep
Abstract The aim of this study was monitoring health status of mastitic Barki ewes using candidate gene approach, gene expression and serum profile of inflammatory and antioxidant markers. A total of 70 ewes were allocated into two equal-sized groups: healthy and ewes have a history of mastitis. DNA sequencing of IFN-γ (365-bp), IL-4 (285-bp), TNF-α (273-bp), MYD88 (660-bp), CCL5 (360-bp), TLR4 (256-bp), TLR9 (414-bp), LTF (299-bp), PRLR (891-bp), CAT (300-bp), GPX1 (221-bp), Keap1 (360-bp), OXSR1 (357-bp), ATOX1 (433-bp), GST (480-bp) and Nrf2 (340-bp) revealed single nucleotide polymorphisms (SNPs) between healthy and mastitic ewes. Levels of IFN-γ, IL-4, TNF-α, MYD88, CCL5, TLR4, TLR9, LTF, PRLR, Keap1 and OXSR1 genes expression were significantly up-regulated in ewes affected with mastitis than resistant ones. Meanwhile CAT, GPX1, ATOX1, GST, and Nrf2 genes elicited an opposite trend. There is a significant elevation of activity of AST, LDH, Hp, CP, SAA, IgG, MDA, and NO levels (P < 0.05), along with reduction of total protein, albumin, GSH, GPx, catalase and SOD (P < 0.05) in mastitic ewes. The findings of this study supported the hypothesis that SNPs in immune and antioxidant genes could be important genetic markers for mastitis susceptibility or resistance in Barki ewes. The examined genes’ gene expression profiles may also be utilized as surrogate biomarkers to establish an efficient management regimen and forecast the period of time at which a disease is most likely to manifest.
Hydroxychloroquine modulates the progression of experimentally induced benign prostatic hyperplasia in rats via targeting EGFR/ERK/STAT3 and AR/FOXO1/TRAIL pathways: computational and in vivo studies
Abstract Benign prostatic hyperplasia (BPH) is a prevalent progressive age-related disorder in men, yet its etiopathophysiology remains poorly understood. Current treatments like finasteride (Fin) have limited long-term efficacy, necessitating alternative therapies. Hydroxychloroquine (HCQ), a safe antimalarial agent, possesses anti-inflammatory, immunomodulatory, and antiproliferative activities, however, its therapeutic effect in BPH has not been investigated. Accordingly, we examined its therapeutic potential and underlying mechanisms, alone or combined with Fin, in testosterone-induced BPH in rats. In BPH-induced rats, HCQ markedly reduced prostate weight and index, and PSA, testosterone, dihydrotestosterone, pro-inflammatory cytokines (TNF-α, κ and IL-6), and the transcription factor “NF-κB” levels, while improving histological abnormalities in epithelial and stromal tissues. HCQ reduced the mRNA expression of AR and ERK1/2, and decreased the protein levels of EGFR and STAT3. Additionally, HCQ increased the mRNA expression of FOXO1 and promoted apoptosis through both intrinsic and TRAIL-mediated pathways. This was evidenced by the upregulation of pro-apoptotic Bax and the downregulation of anti-apoptotic Bcl-2 and Bcl-XL levels in the intrinsic pathway, as well as the reduction in mRNA expression of DR4 and DR5 in the TRAIL-mediated pathway. Notably, combining HCQ with Fin enhanced these effects. Molecular docking revealed HCQ’s strong interactions with androgen receptor (AR), EGFR, ERK1/2, FOXO, and TRAIL death receptors (DR4/DR5), comparable to Fin except for STAT3. Our findings suggest that HCQ modulates BPH progression by targeting STAT3/FOXO1/TRAIL and EGFR/ERK/AR pathways, offering a promising therapeutic strategy for BPH, either alone or in combination with Fin.
Development and validation of a semi-automated algorithm to analyze shear wave elastography clips in muscle tissue
Abstract Ultrasound shear wave elastography (SWE) is broadly used to quantify muscle stiffness. Currently, most stiffness measures are retrieved from manually placed small measurement zones, which is an operator-dependent and laborious procedure of questionable reliability. Automated time-series measurements over the full visible muscle are expected to improve measurement validity, robustness, and efficiency in larger studies. This study aimed to develop and validate a semi-automated algorithm for analyzing SWE clips of muscle tissue using the single-image, manufacturer-provided manual measurements in every image of the corresponding clips as reference. SWE clips of the relaxed and activated upper trapezius muscle of 52 healthy participants were analyzed manually and with the algorithm for the muscle’s Young’s modulus (kPa) and shear wave velocity (SWV). Results demonstrated excellent correlation between manual and algorithm measurements, Spearman’s ρ > 0.99, p < 0.001. Bland–Altman analyses indicated good method agreement with proportional biases of + 0.747 kPa and − 0.068 m/s for Young’s modulus and SWV, respectively, and widths of the limits of agreement of 8.653 kPa and 0.500 m/s, respectively. The proportional bias is within the minimal detectable change and therefore clinically negligible. These results support the algorithm as a tool enabling valid SWE time-series measurements in muscle tissue and an improved workflow.
Postural demands modulate tactile perception in the lower limb in young and older adults
Abstract Balance control requires the continuous integration of feedback signals from several sensory organs with feedforward estimates about the state of the body. Such feedback signals are important for standing upright, as shown in increased and more variable sway patterns when sensory feedback is compromised, for instance when standing with eyes closed or on unstable surfaces that make cutaneous signals from the foot less reliable. Poorer sensory processing is also considered to arise during healthy aging due to a decrease of the reliability and transmission rate of feedback signals. Here, we are interested in how processing of tactile signals from the lower leg is modulated when balance control is challenged and how this interacts with age-related sensorimotor changes. We examined tactile sensitivity on the lower leg during sitting, standing on stable ground, and standing on unstable ground (foam). We quantified the center of pressure during the two standing conditions by determining the area of a 95% confidence interval ellipse as well as the total displacement of the center of pressure. Tactile sensitivity was assessed by asking participants to detect brief vibrotactile probes of various intensities to the lower leg. As expected, postural sway increased when standing on foam than stable ground for both age groups. When postural demands were minimal (sitting), tactile sensitivity was overall poorer in older than younger adults. Tactile perception was also poorer when standing on foam than on the stable ground, for both age groups. We conclude that increased postural demands reduce reliance on tactile signals from the lower limb in both young and older adults.
The role of cognitive and brain reserve in the clinical presentation and progression of amyotrophic lateral sclerosis
Abstract Recent research has shown that cognitive reserve is associated with better cognitive abilities in ALS/MND, and that a slow brain ageing speed is associated with intact cognition in ALS. This study compares the effects of cognitive reserve and the predicted brain age difference (PAD) on the risk of being diagnosed with ALS, the risk of having cognitive or behavioral impairment, or even fronto-temporal dementia, and on disease duration. Our results indicated that neither PAD nor cognitive reserve was associated with an increased risk of ALS, but that higher PAD was associated with an increased risk of cognitive impairments and FTD, as well as a shortened disease duration. Higher cognitive reserve on the other hand was associated with a lower risk of cognitive impairment and a longer disease duration. Brain age as a proxy of brain reserve influences disease progression and presentation more strongly than cognitive reserve.
The effect of sensor-to-source distance on magnetic neuromuscular signals
Abstract Magnetomyography (MMG) can be used as a contactless modality to study the neuromuscular system. On the one hand, being contactless is a practical advantage as there is no need to prepare skin or attach electrodes as in electromyography (EMG). On the other hand, it is also a disadvantage because the magnetic field decays with increasing distance. However, the effect of sensor-to-source distance in MMG has not been systematically studied. Comparative in vivo and in silico experiments of the effect of sensor-to-source distance were performed. In vivo, muscle activity was recorded using simultaneous surface EMG and one triaxial optically pumped magnetometer (OPM). For the simulations, an established multiscale muscle model was used to predict how distance affects the signal-to-noise ratio (SNR) and the signal’s spectral content. Given an environmental noise level of 0.5–1 pT root-mean-square (RMS) from 10 to 350 Hz, it was impossible to robustly detect muscle activity of one finger flexor muscle beyond a distance of two centimeters using OPM technology. In silico experiments showed a high SNR between 8 and 29 for MMG at 0.5 cm distance. Increasing the distance increases the MMG’s median frequency content. The simulations uncovered that this is due to the effect of noise. For distances greater than two centimeters, measuring MMG of voluntary contractions in medium-sized muscles with current OPM technology and conventional magnetic shielding cannot be recommended.
Effects of marine heat waves and cold spells on a polar shallow water ecosystem
Abstract Global warming affects the Earth system in complex ways, often preventing a functional understanding of the underlying processes. Disentangling these processes between abiotic drivers and single species or entire communities is, however, essential for an in-depth understanding of the impacts of climate change on the ecosystem. Using a high-resolution time series on heat waves and cold spells in an Arctic fjord system, we demonstrate that AI-supported digital data processing, which is based on state-of-the-art observatory technology, has the potential to provide new insights into the effects of abiotic factors on biotic communities, which would not be possible with traditional expedition-based sampling methods. Furthermore, our study shows that short-term, event-driven anomalies in key ocean variables not only alter a system’s hydrography but also have the potential to impact the entire community across the trophic chain from benthos and zooplankton to fish. We found a significant positive correlation between hydrographic temperature anomalies and biota abundance, with high biota abundances linked to ‘Atlantic’ phases with frequent heat waves and low biota abundances correlated with ‘Arctic’ phases dominated by cold spells. The study also revealed that hydrographic anomalies can not only influence overall biota abundance in an area but also trigger complex shifts in species composition. This leads to fluctuating interannual abundance peaks in specific biotic groups, such as jellyfish, fish, or chaetognaths, depending on trigger factors that are not yet fully understood.
A novel approach to exploring infant gaze patterns with AI-manipulated videos
Abstract Eye tracking is a widely used tool to study infant development, but creating diverse stimuli while maintaining high control over confounding variables can be challenging. In this proof-of-concept study, we examined an innovative way to generate ecologically valid stimuli using AI technology, in order to create videos that can be used in culturally diverse settings. Using the eye-mouth-index (EMI), a commonly used paradigm in infant eye tracking, we examined the consistency of eye tracking measures across original videos and two types of AI-manipulated videos in a sample of 46 infants aged 12–14 months. We found a very strong correlation of the EMI across original and AI videos (r = 0.873–0.874), and there were no statistically significant differences between mean EMI in the original and AI conditions. Additionally, we created culturally diverse videos to measure gaze following, and found that children followed the gaze of the people in the AI-manipulated videos in an expected manner. In conclusion, AI technology provides promising tools to create ecologically valid and culturally diverse stimuli, that can be used to conduct studies in a wide range of settings and to examine the generalizability of earlier findings in the field of developmental psychology.