Browse Articles

Influence of the SARS-CoV-2 pandemic and infection on musculoskeletal function

Abstract As of September 2023, the number of SARS-CoV-2 infections worldwide has exceeded 770 million, with ongoing research recognizing its long-term health effects. This study investigates the effects of the pandemic on participants with and without SARS-CoV-2 infection on musculoskeletal status. The Hamburg City Health Study (HCHS) is an ongoing, prospective, population-based cohort study (trial registration number: NCT03934957). Participants (n = 2660) examined prior to the SARS-CoV-2 pandemic were compared with non-infected participants (n = 2660) in a 1:1 matched cohort analysis after the pandemic onset. Furthermore, participants who had recovered from a SARS-CoV-2 infection (n = 428) were compared with non-infected participants (n = 1712) in 1:4 matched cohort analysis. Increased relative fat mass and reduced skeletal muscle mass were observed in the post-pandemic group. No significant differences were observed between the groups regarding handgrip strength and timed up and go test. The comparison of the infection group with non-infected participants showed no significant differences in relative fat mass, handgrip strength and timed up and go test. The skeletal muscle mass was increased in the infection group but linear regression analysis adjusted for body surface area revealed no significant differences. This prospective study shows no association between SARS-CoV-2 infection and changes in basic musculoskeletal parameters in the cohort studied, suggesting that the infection may not be a significant cause of major deterioration in musculoskeletal function. Instead, it appears that lifestyle changes in daily routines and physical activities associated with the pandemic itself are the main influence on the musculoskeletal system.

Detecting unacceptable behavior of an autonomous vehicle using electroencephalography

Abstract In the present study, we investigated event related potentials (ERPs) in the context of autonomous driving - specifically in left-turn situations through oncoming traffic. We recorded electroencephalography while participants (n = 33) observed a simulated autonomous vehicle executing a left turn maneuver through oncoming traffic. In the ERP, we observed an increased N2 (251 to 431 ms) when the AV behaved incongruently to the participant’s assessment of the turn situation compared to when it behaved congruently. There were no significant effects in N1 (142 to 182 ms), P2 (177 to 237 ms), nor P3 (439 to 689 ms). This suggests that, in human-AV interaction interaction, ERP-based devices might, in the future, be able to identify critical situations. However, further research is needed to bring current findings from fundamental research closer to application.

Petrophysical assessment of reservoir quality and recoverable reserves in fluviodeltaic Nubian sandstone Saqqara field Gulf of Suez Egypt

Abstract Heterogeneous reservoirs require integrated petrophysical rigor to improve the accuracy of hydrocarbon reserve calculation, minimize uncertainty in reservoir characterization, and optimize development options. Using the Fluvio-Deltaic Nubian Sandstone in the Saqqara Field, Gulf of Suez, as an example, this study uses multi-petrophysical workflows, such as well-log correlation, core-log calibration, petrophysical evaluation, petrophysical distribution maps, and multi-petrophysical cross-plot for lithology, fluid saturation, and reservoir parameters, across four important wells (GS323-1, GS323-2 A, GS323-3, and GS323-4 A). Original hydrocarbons in place (OHIP) and recoverable reserves were calculated using volumetric methods, and thermal maturity was evaluated using geothermal gradient estimations. Lithological interpretation, based on neutron-density cross-plots, confirms the dominance of clean sandstone with minimal clay and anhydrite cementation. Thermal analysis indicates a moderate geothermal gradient (~ 2.75 °C/100 m) and formation temperature (~ 147 °C), supporting hydrocarbon maturation. The reservoir exhibits excellent quality, with low shale volume (~ 0.6%), total porosity averaging 13.5%, and high hydrocarbon saturation (~ 78.5%). Despite variations in permeability, significant net pay zones (ranging from 108.5 to 481.5 ft) offer robust development potential. Using volumetric methods, the estimated hydrocarbons in place reach ~ 106 billion barrels, with ~ 31 × 10 9 barrels considered recoverable. These findings highlight the strategic value of the Nubian Formation in hydrocarbon planning and underline the critical role of integrated petrophysical analysis in maximizing production efficiency in mature basins. Moreover, the insights derived from this study can be effectively applied to similar sandstone reservoirs worldwide, contributing to improved resource management and energy security.

Antibacterial synergistic behaviour of phytosynthesized magnesium oxide nanoparticles with clove essential oil

Abstract While researchers continue to search for new antibacterial agents, combination therapy as well as nanotechnology-based treatments allure as promising approaches to tackle antibiotic resistance. The present study aimed to phytosynthesize magnesium oxide NPs (MgO NPs and evaluate their potential antibacterial synergistic behaviour with different essential oils (EOs). MgO NPs phytosynthesized using thyme aqueous extract were quasi-spherical with an average size of 55.2 ± 12.8 nm and an elemental composition of 35.39% Mg and 51.07% O, as determined by SEM-EDX. FTIR elicited characteristic functional group peaks, while XRD confirmed their cubic crystal structure. The phytosynthesized MgO NPs and four EOs displayed variable antibacterial activity against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. The checkerboard assay revealed that only clove and thyme EOs showed synergistic effects in combination with MgO NPs. Notably, MgO NPs-clove EO combination caused significant bacterial membrane damage as compared to their single counterparts in both S. aureus and E. coli. Moreover, oxidative stress was induced, as observed by the significant increase in the antioxidant enzyme activities (superoxide dismutase and catalase). Conclusively, the present results provide insights into the promising compounding of green-synthesized MgO NPs and clove EO as a bio-efficacious and eco-friendly approach to curtail antibiotic resistance.

Competency of improved artificial ecosystem optimizer in parameters identification of small and medium sized distribution transformers

Abstract Accurate modelling of distribution transformers (TXs) is crucial to identify their operating characteristics across several power system applications. Consequently, this paper employs an improved version of the artificial ecosystem optimizer (called IAEO) in parameters estimation of distribution TXs with different four sizes (i.e. 4, 15, 112.5 and 167 kVA ratings). Comparison with well-known literature optimizers, including genetic algorithm, particle swarm optimizer, coyote optimization algorithm, artificial hummingbird optimizer, and others, validates the performance of the proposed IAEO. The IAEO demonstrates its superiority by getting the lowest possible value of the sum of absolute errors (SAEs) between measured and calculated values, which serves as the objective function (OF) to be optimized. Moreover, three additional optimizers are employed and compared to IAEO for all study cases: firefly algorithm, political optimizer, and exponential distribution optimizer. It is found that IAEO attains the minimum SAEs values of 1.12e-5 and 0.0322, outperforming the best competitors for 4 kVA and 15 kVA TXs, respectively. Furthermore, IAEO accurately captures the steady state fingerprint of all studied TXs in terms of efficiency and voltage regulation (VR). This way, the peak efficiency occurs at 36.2% loading in 112.5 kVA TX while the negative VR may reach -8% when the 167 kVA TX is loaded with its rated leading power factor. Finally, all executed optimizers are analyzed using several statistical indices, including t-test, where the proposed IAEO gets the smoothest and fastest OF minimization trend.

Assessing the potential of bacterial signal peptides for radiopharmaceutical applications

Abstract Bacterial signal peptides are a large group of high-affinity ligands for formyl peptide receptors (FPRs). These receptors are highly enriched on the surface of glioblastomas and several other tumor types. In this study, we evaluated the potential of bacterial signal peptides, a yet relatively unexplored class of high affinity FPR agonist for radiopharmaceutical applications. We tested a range of bacterial signal peptides and their fluorescently labeled derivatives to identify peptide residues that allow chemical modification without drastic loss of affinity. We then developed a selective fluorescent peptide derivative with more than 1000-fold selectivity towards FPR1, which binds rapidly at low nanomolar concentrations and forms stable receptor-ligand complexes that can persist for up to 72 h. This peptide probe effectively bound to a human glioma cell line U87-MG and efficiently penetrated spheroids derived from U87-MG cells. Finally, we have designed a corresponding metal chelate-peptide conjugate with similar affinity that is taken up by FPR1-transfected HEK293T cells and naturally FPR1-expressing U87-MG cells. A pilot study with planar scintigraphy in healthy mice showed no substantial uptake or retention in healthy organs, suggesting that bacterial signal peptides could indeed be an interesting tool for the development of radiopharmaceuticals.

Effects of nighttime odor exposure and delivery methods on subjective sleep quality in healthy adults

Abstract The role of smell in improving sleep quality is inconclusive. This study aimed to investigate whether the type of odor and the method of application affect sleep quality. Based on individual preference 112 healthy participants (mean age ± SD = 31 ± 12 years, 43 men) selected an odor (lavender, orange, specifically designed “perfume”) and an application method (odorized nasal clips, odors on pillow, odors through diffuser). Their performance was compared to a control group (n = 19; mean age ± SD = 29 ± 6 years, 9 men). Except for the control group, all groups slept with exposure of odor for 2 weeks (phase 1), followed by 2 more weeks of normal sleep without odors (phase 2). The Pittsburgh Sleep Quality Index (PSQI) and the wearable sleep monitoring device “Fitbit Charge 2” were used to measure sleep quality both subjectively and objectively. After adjusting for baseline differences, participants exposed to “perfume” reported better subjective sleep quality during the odor exposure phase compared to the control group. Among the application evaluated, the use of a diffuser was associated with better subjective sleep quality and reduced daytime fatigue, as reflected in the PSQI components. No significant group differences were observed in objective sleep parameters measured by Fitbit. Exposure to odors during the night influence sleep quality. Using a diffuser to deliver the odor appears to be associated with better subjective sleep quality and reduced daytime fatigue. No sustained improvement in sleep quality over time was observed with odor exposure.

Effect of port-site and intraperitoneal local anesthetic injection versus placebo on postoperative pain and recovery after gynecologic laparoscopic surgery: a randomized controlled trial

Abstract Laparoscopic gynecological surgery, while minimally invasive, is frequently associated with significant postoperative pain requiring systemic analgesics. Local anesthetic administration, either intraperitoneally or at trocar sites, has been proposed to improve analgesia and recovery, but evidence remains inconsistent. To evaluate and compare the efficacy of intraperitoneal and port-site local anesthetic injection versus placebo in reducing postoperative pain and improving recovery outcomes in women undergoing gynecological laparoscopic surgery. This randomized, double-blind, three-arm controlled trial enrolled 90 women aged 18–60 years undergoing elective gynecological laparoscopy at Kasr Al-Ainy Hospital, Cairo, Egypt (March 2024–March 2025; ClinicalTrials.gov NCT07030647). Participants were randomized into: Group A (trocar site bupivacaine 0.25%), Group B (intraperitoneal bupivacaine 0.25%), and Group C (saline placebo). Postoperative pain was assessed using a visual analog scale (VAS) at 1, 6, 12, and 24 h. Secondary outcomes included rescue diclofenac use, time to first analgesic, total diclofenac dose, time to ambulation, hospital stay, and patient satisfaction. Baseline demographics were comparable across groups. Group B reported the lowest pain scores at 1, 6, and 12 h (0.1 ± 0.3; 2.9 ± 1.1; 2.1 ± 0.3, respectively), followed by Group A, while Group C had the highest (p < 0.001). At 24 h, pain scores were similar (p = 0.087). Diclofenac requirement was significantly reduced in Group B (26.7%) compared to Groups A (83.3%) and C (100%) (p < 0.001). Time to first rescue analgesic was longest in Group B (7.1 ± 1.1 h vs. 2.9 ± 0.7 and 1.5 ± 0.8; p < 0.001). Total 24-hour diclofenac consumption was lowest in Group B (75 mg) versus Groups A (114 ± 38.2 mg) and C (142.5 ± 22.9 mg; p < 0.001). Early ambulation occurred fastest in Group B (3.5 ± 0.9 h), followed by Group A (5.1 ± 0.6 h) and Group C (6.9 ± 0.8 h; p < 0.001). Hospital stay was 24 h in all groups. Patient satisfaction was highest in Group B (7.3 ± 1.2), intermediate in Group A (4.2 ± 1.6), and lowest in Group C (3.0 ± 0.8; p < 0.001). Both intraperitoneal and trocar site local anesthetic administration significantly reduced postoperative pain and analgesic requirements compared with placebo. Intraperitoneal administration demonstrated superior efficacy, leading to earlier ambulation and higher patient satisfaction. Routine use of intraperitoneal local anesthetic may enhance postoperative recovery in gynecological laparoscopy. Trial registration ClinicalTrials.gov Identifier: NCT07030647 (retrospectively registered 20 June 2025).

An experimental study on double longitudinal plate connection for steel T-joints subject to out-of-plane moments

Abstract Square hollow section (SHS) is widely used as a chord member in steel trusses. In one connection type, a brace using I-shape or box section at a T-joint transfers out-of-plane bending moment to these chords through double longitudinal plates. Design codes include rules for different connections to hollow sections, but not specifically for this detail. An experimental program is presented in this paper to verify relevant design rules and apply them to the double-plate connection, considering three key parameters: double-plate spacing, connection offset from the chord centerline, and plate width. The test results are evaluated by discussing the connection capacity and the observed failure modes, in addition to plotting both the load-displacement and moment-rotation curves. Applying relative rules from code is found to be on the conservative side and requires adjustment to apply to the current context. However, the rules for single plates are found to be adequate for some of the eccentric double-plate connections with a plate at the chord face center. Some modifications to the existing design rules are proposed to suit the eccentric connection with a plate not at the center.

In vivo tibialis anterior muscle mechanics through force estimation using ankle joint moment and shear wave elastography

Abstract Understanding how individual muscles contribute to joint mechanics is crucial for biomechanics. This study investigated the tibialis anterior (TA) shear modulus using shear wave elastography (SWE) and studied its relationship with ankle angle, contraction intensity, and joint moment-derived TA force and stress. Fourteen healthy volunteers (seven females, 26.43 ± 3.67 years) participated. SWE from TA, EMG, and ankle joint moment data were collected across ankle angles (− 15° dorsiflexion to 45° plantar flexion) during rest, maximum voluntary contraction (MVC), and isometric submaximal contractions. TA muscle length, passive ankle joint moment, and TA passive shear modulus increased with increasing plantar flexion (p < 0.001). During MVC, ankle joint moment peaked at 15° (50.13 Nm ± 15.54 Nm) whereas shear modulus remained unchanged (122.96 ± 9.87 kPa) across muscle lengths (p = 0.068). SWE reflected contractions at 25%, 50%, and 75% MVC (p < 0.001). TA force estimates peaked between 15° and 30°, with no significant decrease beyond this range. While SWE captured length-dependent passive properties and contraction intensity changes, the shear modulus at MVC (a stiffness measure obtained from SWE) did not align with the tangent modulus (derived from joint-moment-based force–length characteristics). Emphasizing the need for validation, SWE could serve as a valuable tool for understanding muscle mechanics and muscles’ roles in joint dynamics.

Cerebral microstructural alterations as an imaging biomarker for Post-COVID-condition

Abstract To develop an imaging biomarker-based approach for the diagnosis of Post-COVID-condition (PCC) at the individual patient level. Magnetic resonance imaging (MRI) data from a prospective cohort of PCC patients (n = 89) were compared with a control group of unimpaired individuals who had contracted coronavirus disease 2019 (COVID-19) in the past (n = 38). Participants were divided into two groups: a training and a test cohort. The macrostructure, diffusion tensor imaging, and multi-shell-based microstructure imaging metrics were extracted using an atlas-based approach. These data were subsequently utilized to train a linear support vector machine (SVM). The efficacy of discrimination between the groups was evaluated for various combinations of input parameters. Upon comparison of the different input combinations, we found the highest area under the receiver operating characteristic curve (AUROC) for microstructural parameters. For the optimal combination of input parameters, an AUROC value of 0.95 with a sensitivity of 94% and a specificity of 85% was achieved, indicating high discriminatory potential but also underscoring the need for further validation given the non-negligible false-positive rate. The atlas regions with the highest discriminatory power include both gray (including multiple cortical areas, putamen and left thalamus) and white matter (including corpus callosum and frontal white matter). The use of a SVM allowed for the differentiation between PCC patients and UPC participants with high sensitivity using microstructural MRI data. While these findings mark a significant step toward a biomarker-based diagnosis of PCC, the moderate specificity and the monocentric design emphasize the need for confirmation in larger and multicentric cohorts before clinical application.

Extracellular vesicle-associated transcriptomic and proteomic biomarkers show in vitro potential for vandetanib treatment monitoring in anaplastic thyroid cancer

Abstract Anaplastic thyroid cancer (ATC) is an aggressive and rare disease. Rapid metastasis and limited treatments call for additional therapeutic options, including drug repurposing. The early spreading of ATC highlights the importance of rapid therapy success assessment, which could be achieved by measurement of extracellular vesicle (EV)-associated cell-free RNA in liquid biopsy samples. Recent studies have discovered the potential of the receptor tyrosine kinase inhibitor vandetanib for ATC treatment in vitro and in vivo. Given the rarity of ATC patients receiving off-label vandetanib treatment, acquiring patient samples for clinical studies is a prolonged process, and pre-clinical investigations are needed to elucidate the effects of vandetanib on ATC cells. Here, we present an in vitro study addressing holistic transcriptional and proteomic changes induced in the ATC cell line Cal62 by three doses of vandetanib and quantified by high-throughput methods. By comparing the transcriptional and proteomic data sets and applying dimensional reduction models such as sparse partial least-squares discriminant analysis, we refined a set of 21 biomarker candidates. Out of these, we report a final signature of eight transcriptional biomarkers, validated in cellular and cell-free RNA by RT-qPCR and verified for biological significance and discriminatory power by pathway over-representation analysis and partial least-squares regression. This transcriptional biomarker signature can distinguish vandetanib treatment from control in cell-free RNA isolated from Cal62 EVs and can be measured reliably, easily, and quickly using RT-qPCR. Our findings may serve as a basis for future clinical trials with liquid biopsy samples from ATC patients undergoing off-label vandetanib treatment.

SDC2 and FN as cargo proteins in circulating extracellular vesicles in obese breast cancer patients with lymph node metastasis

Abstract Lymph node metastasis (LNM) is a pivotal determinant of breast cancer (BC) patient prognosis and treatment efficacy. Cell surface heparan sulfate proteoglycans (HSPGs), namely, syndecan-1 (SDC1), SDC2, and SDC4, are involved in cancer progression, metastasis, and regulate extracellular vesicles (EVs) biogenesis, including the microvesicles (MVs). This study analyzed MV-enriched EVs isolated from blood plasma of BC patients with negative (n = 19) and positive (n = 20) LNM (nLNM and pLNM, respectively) using differential centrifugation. Western blot analysis revealed significantly elevated SDC2 levels in MV-enriched EVs from pLNM cases compared to nLNM. Additionally, fibronectin (FN), a SDC2-interacting protein identified through STRING analysis, was also upregulated in pLNM MV-enriched EVs. In contrast, qRT-PCR showed reduced SDC2 (P < 0.01) and FN (P < 0.05) mRNA levels in tumor tissues of pLNM patients compared to nLNM. ROC analysis highlighted the diagnostic value of SDC2 (AUC: 0.8376) and FN (AUC: 0.8803) mRNA in differentiating LNM status. Bioinformatics analyses further confirmed the association of SDC2 and FN expression with BC staging and prognosis. These findings underscore the potential of circulating MV-enriched EV-associated SDC2 and FN, along with their tumor tissue mRNA expression, as potential predictive biomarkers for LNM and chemotherapy response in chemotherapy-naïve obese BC patients.

Internal quality assessment of blood components at Mansoura university blood transfusion center

Abstract In modern blood banking, quality control of blood products ensures the timely availability of a blood component of high-quality yield with maximum efficacy and minimal risk to potential recipients. A prospective cross-sectional study was carried out at Mansoura University Hospital Blood Bank (MUHBB) aiming to assess the internal quality control (IQC) of 300 units of each blood components, red blood cell concentrates (RBCs), fresh frozen plasma (FFP), and platelet concentrates (PCs), and to explore their compliance with The Egyptian National Blood Transfusion Services (NBTS ),The American Association of Blood Banks (AABB), and Council of Europe (CE) standard criteria. IQC of different blood products was accepted if > 90% of units were fulfilled the standard requirements. The results of our study show that the total compliance of RBCs was 93.3% according to NBTS and CE standards and 96% as regards AABB standards. The total compliance of FFP was 94.0% according to NBTS and CE standards and 96.0% as regards AABB standards. While the total compliance of PCs was 96.0% according to NBTS and AABB standards and 93.3% as regards CE standards. Continuous improvement is recommended to decrease the percentage of noncompliance in the QC parameters included in our study and to uplift the blood transfusion practices.

Exploring the potential of hydro alcoholic crude extract of beeswax as antibacterial antifungal antiviral antiinflammatory and antioxidant agent

Abstract Apis mellifera beeswax is synthesized from honey sugars and secreted by specialized glands located on the ventral side of the abdomen of worker bees aged 12–18 days. This beeswax possesses various therapeutic properties beneficial to human health. Given the priority in pharmacological research to develop new drugs from natural sources with minimal side effects, the absence of studies on the biological activities of A. mellifera beeswax is notable. Therefore, this study aims to investigate the chemical composition, as well as the anti-inflammatory, antiviral, cytotoxic, antimicrobial, and antioxidant activities of hydroethanolic crude beeswax extract from A. mellifera. The results revealed the presence of the flavonoids rutin (19.39 µg/g), naringenin (69.52 µg/g), daidzein (3.34 µg/g), quercetin (53.69 µg/g), kaempferol (51.88 µg/g), hesperetin (8.13 µg/g) and the phenolic gallic acid (421.13 µg/g), chlorogenic acid (878.80 µg/g), methyl gallate (56.21 µg/g), caffeic acid (8.83 µg/g), syringic acid (8.07 µg/g), coumaric acid (9.80 µg/g) and cinnamic acid (4.94 µg/g) which assessed by HPLC. Apis mellifera beeswax had considerable anti-inflammatory activity percent hemolysis Inhibition was 90.2% at concentration 1000 µg/mL, while indomethacin (standard drug) showed 100% activity at the same concentration. Also, exhibited major antioxidant activity as assessed by DPPH radical scavenging activity assay which compared to ascorbic acid, the IC50 of A. mellifera beeswax was 16.93 µg/mL. The antiviral activity of A. mellifera beeswax against HAV was recorded at 78.52%, while it was 24.2% against CoxB4 at the same concentration. The beeswax of A. mellifera demonstrated greater inhibitory activity than the reference compound gentamicin against Staphylococcus aureus (25 ± 0.18 mm) and Escherichia coli (15 ± 0.81 mm). It also showed significant inhibitory activity against Candida auris (22 ± 0.21 mm). Moderate inhibitory effects were observed against Klebsiella pneumoniae (19 ± 0.36 mm), Enterobacter aerogenes (14 ± 0.46 mm), and Candida albicans (15 ± 0.13 mm). The minimum lethal concentrations and minimum inhibitory concentrations of A. mellifera beeswax against these pathogenic strains ranged from 125 to 250 μg/mL and 62.5–125 μg/mL, respectively. The findings of this study highlight the substantial biological potential of beeswax extract, suggesting that A. mellifera beeswax warrants further investigation as a source for new pharmacological alternatives. However, additional in vitro and in vivo studies are necessary to fully assess its potential benefits for human health.

Enhanced oil recovery from sandstone reservoir using cationic hyperbranched polyamidoamine dendrimer surfactant flooding under real reservoir conditions

Abstract This study investigates the application of a synthesized cationic hyperbranched polyamidoamine (PAMAM) dendrimer surfactant (G2-C12) as a novel chemical agent for enhanced oil recovery (EOR) in sandstone reservoirs under realistic high-salinity and high-temperature conditions. The dendrimer was synthesized via a divergent approach involving Michael addition, amidation, and quaternization, yielding a structurally defined amphiphilic macromolecule. Its performance was evaluated through interfacial tension (IFT) measurements, salinity-dependent behavior, wettability alteration tests, and core flooding experiments. The surfactant reduced IFT from 27 mN/m to 5 mN/m at 2000 ppm, which was identified as the critical micelle concentration (CMC). Contact angle measurements confirmed a significant shift from oil-wet to strongly water-wet conditions (10.87°–34.57°). Additional salinity tests established the optimal brine strength, while core flooding results demonstrated an incremental oil recovery of 29.09% at reservoir-representative conditions. These findings underscore the dendrimer’s dual-function mechanism, operational stability, and strong potential as a high-performance EOR surfactant under challenging field environments.

In vitro assessment of fracture resistance of premolar teeth restored with diatomite zirconia versus barium glass filled resin composite

Impact of chewing muscle anesthesia on masticatory performance in healthy participants

Abstract The impact of the muscle spindles in the masticatory performance remains elucidated. This study aimed to investigate the impact of local anesthesia in the jaw-closing muscles on masticatory performance in healthy participants. Thirty healthy pain-free volunteers underwent in two rounds of chewing tasks involving two types of viscoelastic candies and a two-coloured chewing gum. Lidocaine (3.0 mL) was injected into a total of six points in the masseter and temporalis muscles bilaterally for the second round. Pain intensity, fatigue, the number and area of particles, and the degree of mixing of the chewing gum were assessed at baseline and after each round of chewing. The number of candy particles after injection of lidocaine, was significantly lower (33%) for women compared to the results without anesthesia (p < 0.05). There was no significant difference in the variance of hue of the two-coloured chewing-gum when comparing values before and after anesthesia. None of the participants experienced any pain during the experiment. However, self-reported fatigue increased during the second round, i.e., after anesthesia, with significantly higher values observed at the final assessment point. (p = 0.029). Local anesthesia of the jaw-closing muscles appears to impair the masticatory function in women, leading to reduced efficiency in food comminution compared to normal mastication. The observed sex differences suggest that women may be more vulnerable to neuromuscular control alterations following sensory alterations.

Correction: The impact of the integrated people-centered eye care model on myopia control among children and adolescents in China

Increased frontal functional connectivity correlates with structural disconnection in the anterior corpus callosum in healthy older adults

Abstract Cognitive aging is a heterogeneous process characterized by a varied decline in brain performance. While the neurophysiological basis of this decline remains poorly understood, age-related alterations in structural connectivity (SC) and functional connectivity (FC) have been implicated. Understanding the relationship between these changes is crucial for identifying early markers of cognitive impairment. In our previous work, we observed that in healthy older adults, diminished performance in a tactile recognition task was associated with reduced fractional anisotropy (FA) in the anterior corpus callosum (aCC). The aim of this study was to investigate the impact of this age-related SC degeneration on the FC between the connected regions. In the current analysis, we examined resting-state functional MRI data from 29 healthy older adults, who were categorized into two subgroups - high and low performers - based on their performance in a tactile recognition task and a younger control group (N = 20). We conducted a region of interest (ROI) to ROI analysis to evaluate FC between frontal regions connected via the aCC. Subsequently, we compared the FC between the groups and assessed its correlation with FA values in the aCC across all older participants based on a TBSS analysis from our previous work. We found that poorer performance in a tactile recognition task was associated with increased FC between frontal regions. The second main finding was a negative correlation between FA in the aCC and FC between frontal regions. Our findings suggest that structural degradation of the underlying pathways may initially lead to increased FC within the connected regions, possibly as a compensatory mechanism to preserve cognitive function. However, as no direct brain–behavior correlation was assessed, this interpretation remains tentative. The aCC appears to be particularly vulnerable to age-related structural decline, which may underlie functional changes in frontal regions observed with aging.