Effect Of Age Research Articles

Selection and re-selection throughout a national talent pathway: Exploring longitudinal relative age effects in Northern Ireland male soccer

ABSTRACT The purpose of this study was to investigate the longitudinal prevalence of relative age effects (RAEs) across playing levels and positions in Northern Ireland international male soccer. Birthdates of U17 (n = 276), U19 (n = 320), U21 (n = 331), and senior (n = 108) international players between 2011 and 2023 were recorded. Chi-square tests and odds ratios with 95% confidence intervals were used to compare observed and expected birthdate distributions. A selection bias toward relatively older players was evident at U17 and U19 playing levels as well as defensive and midfield positions. In contrast, more relatively younger senior and forward players were selected. Longitudinal analyses revealed that of those players who were initially selected at U17, more relatively older players were re-selected at subsequent playing levels, but there were no birthdate asymmetries amongst new players added after U17. The results of this study demonstrate RAEs are prevalent across Northern Ireland international male soccer and are influenced by playing level as well as position. These findings have important implications for policy makers and practitioners as relatively older players are overrepresented at youth but not senior level, which questions the efficacy of this (un)conscious bias in the talent pathway.

Effect of Age on the Pharmacokinetics of Marbofloxacin Following Intravenous Administration in Calves.

The aim of this study was to compare the pharmacokinetics of marbofloxacin after intravenous (IV) administration of a single dose of 10 mg/kg to calves of different ages. The study was carried on 1- (n = 6), 2- (n = 6), and 4-month-old (n = 6) Montofon calves. Plasma concentrations of marbofloxacin were measured using HPLC, and pharmacokinetic data were calculated by non-compartmental analysis. The elimination half-life (t1/2ʎz), volume of distribution at steady state (Vdss), total clearance (ClT), and area under the concentration-versus time curve (AUC0-∞) values of marbofloxacin in 1-month-old calves were 10.62 h, 1.03 L/kg, 0.08 L/h/kg, and 127.90 h*μg/mL, respectively. While the t1/2ʎz (from 10.62 to 3.36 h) and AUC0-∞ (from 127.90 to 47.35 h*μg/mL) decreased in parallel with the age of the calves, ClT (from 0.08 to 0.21 L/h/kg) increased. The Vdss of marbofloxacin was higher in 1- and 2-month-old calves compared to 4-month-old calves. After IV administration of marbofloxacin at a dose of 10 mg/kg, an ƒAUC0-24/MIC90 ratio of ≥ 125 was obtained for bacteria with MIC90 values of ≤ 0.60, ≤ 0.39 and ≤ 0.27 μg/mL in 1-, 2-, and 4-month-old calves, respectively. These results show that the antibacterial effect of marbofloxacin, which has concentration-dependent activity, decreases due to age-related pharmacokinetic changes and that the 10 mg/kg dose should be reviewed according to the MIC90 value of the bacteria.

Prognostic factors for disease activity in newly diagnosed teriflunomide-treated patients with multiple sclerosis: a nationwide Danish study

BackgroundClinicians frequently rely on relapse counts, T2 MRI lesion load (T2L) and Expanded Disability Status Scale (EDSS) scores to guide treatment decisions for individuals diagnosed with multiple sclerosis (MS). This...

Oculomotor Findings in Videonystagmography across the Lifespan.

When performing oculomotor testing during standard videonystagmography (VNG), the vestibular system is not actively stimulated. Therefore, responses are generated from the cerebellum, brainstem, and oculomotor tract. Many patients seen for vestibular testing fall outside of the standard age norms, making it difficult to determine whether an abnormal finding is due to age or oculomotor dysfunction. The purpose of this study was to further evaluate the effect of age on a standard clinical VNG oculomotor test battery consisting of saccades, smooth pursuit, and optokinetic (OPK) testing. This is a cross-sectional, between-group prospective study comparing oculomotor tests between age groups. Twenty-one older adults between the ages of 60 and 90 years with no history of central or peripheral vestibular dysfunction were included in the study. Previously collected data from 29 children aged 4 to 6 years and 33 adults aged 20 to 60 years were also included. Participants completed oculomotor testing using infrared goggles consisting of saccades, smooth pursuit, and OPK. Statistical analyses were completed using multivariate analysis of variance and analysis of variance and follow-up analysis when indicated. Significant group differences were noted for saccade latency and speed, smooth pursuit gain, and OPK gain and speed. Children and older adults demonstrated longer saccade latencies compared with the controls, and older adults exhibited slower saccade speed than the controls and children. These results also indicated that smooth pursuit gain was reduced for children and older adults compared with controls, and gain decreased across all groups as frequency increased. Analyses of OPK results indicated older adults had reduced gain and speed compared with the children and control group. The findings of prolonged saccade latencies and reduced smooth pursuit gain in both children and older adults suggest possible cerebellar rather than attentional effects. However, other findings such as reduced saccade speed and reduced OPK gain were noted only in the older adults, which suggests oculomotor degeneration and/or insufficient coverage of the visual field during testing, respectively. These results also indicate the importance of age-specific normative data for use in clinical oculomotor testing.

The Development of Ambiguity Processing Is Explained by an Inverted U-Shaped Curve

Understanding the developmental trajectories for recognizing facial expressions is important for a better understanding of development of psychiatric disorders. In this study, we examined the recognition of emotional and neutral facial expressions in 93 typically developing adolescents and adults. The Emotion Intensity Rating task required participants to rate the intensity of emotional expression in happy, neutral, and sad faces on a scale from 1 to 9. A score of ‘5’ had to be assigned to neutral faces, scores between ‘6’ (slightly happy) and ‘9’ (very happy) to happy faces, and scores between ‘4’ (slightly sad) and ‘1’ (very sad) to sad faces. Mixed effects models were used to examine the effects of age and emotion on recognition accuracy, reaction time (RT), and emotional intensity. Participants tended to misjudge neutral faces as sad. Adolescents were less accurate than adults for neutral face recognition. There were significant quadratic effects of age on accuracy (negative quadratic effect) and RT (positive quadratic effect). The most accurate and fastest performance was observed in 25- to 35-year-old subjects. This trajectory may be associated with prefrontal cortex maturation, which provides top–down control over the heightened amygdala response to ambiguity that may be misinterpreted as emotional content.

Anisotropic spin-glass-like behavior in single crystal GdCo2B2

A high-quality single crystal of GdCo2B2 was successfully synthesized and subjected to a comprehensive investigation into its spin-glass characteristics. We conducted a systematic analysis of magnetization, aging effects, and alternating current (AC) susceptibility. Interestingly, a clear separation was observed between the zero-field-cooled (ZFC) and field-cooled (FC) magnetization curves under low magnetic field of 0.01 T. Furthermore, the crystal exhibited a long-time relaxation behavior at 4 K. The freezing temperature increases with frequency increasing. Additionally, we explored the response of the crystal to DC magnetization and AC susceptibility under different pressure conditions, up to 1.58 GPa. The crystal exhibits three anomalies TC = 22.0 K, T1 = 20.5 K and TN = 11.0 K under ambient pressure. An analysis of the anisotropy of the spin-glass-like behavior in the crystal was conducted, with a specific focus on the a-axis as the preferred direction of magnetization. All of the results provide evidence for the coexistence of mixed ordering states in the crystal.

Sleep restriction and age effects on distinct aspects of cognition in adolescents.

Insufficient sleep negatively impacts scholastic performance in children and adolescents. Here we use a dose response time in bed (TIB) restriction study to evaluate associations between sleep loss and multiple aspects of cognition. We evaluated changes in cognitive measures across ages 10 to 23 years and determined whether the effects of sleep loss changed across this age range. A younger cohort (n=77, age range 9.9 to 16.2 years) was studied annually for 3 years. An older cohort study (n=82, age range 15 to 22.8 years) was interrupted by the COVID pandemic with 25 participants completing multiple years. Annually participants completed each of three TIB conditions: four consecutive nights with 7, 8.5, or 10h in bed. A day of cognitive testing followed the fourth night. Restricting TIB to 7h was associated with impaired top-down attentional control and cognitive flexibility, but performance did not differ between the 8.5 and 10h TIB conditions. Psychomotor vigilance test performance decreased as TIB was restricted from 10 to 8.5h and decreased further with restriction to 7h. Sternberg test measures of working memory were not significantly affected by TIB restriction. The effects of sleep loss on these cognitive measures did not change significantly with age, but age-related improvement in many of the measures may compensate for some sleep loss effects. The findings here do not indicate an adolescent decrease in sleep need; however, the minimal duration of sleep needed for optimal performance appears to differ depending on the cognitive measure.

Effects of Pre-deformation and Peak Aging on Mechanical and Damping Properties of (CNTs + AlN)/AZ91 Composite

Effects of Pre-deformation and Peak Aging on Mechanical and Damping Properties of (CNTs + AlN)/AZ91 Composite

Fat body lipogenic capacity in honey bee workers is affected by age, social role and dietary protein.

All organisms need to balance processes that consume energy against those that produce energy. With an increase in biological complexity over evolutionary time, regulation of this balance has become much more complex, resulting in specialization of metabolic tasks between organelles, cells, organs and, in the case of eusocial organisms, between the individuals that comprise the 'superorganism'. Exemplifying this, nurse honey bees maintain high abdominal lipids, while foragers have very low lipid stores, likely contributing to efficient performance of their social role, and thus to colony fitness. The proximate mechanisms responsible for these metabolic differences remain poorly understood. Here, we investigated the effects of age, worker class and dietary macronutrients on the abdominal activity of fatty acid synthase (FAS), the enzyme responsible for de novo synthesis of fatty acids, as well as the effects of age on lipase activity, enzymes responsible for the breakdown of stored lipids. We found that FAS but not lipase activity declines as bees age past peak nursing age. Feeding both nurses and foragers carbohydrates increased FAS activity compared with starved bees, but, whether fed or starved, nurses had much higher FAS activity than similarly treated foragers, implicating reduced lipid synthesis as one component of foragers' low lipid stores. Finally, we used artificial diets with different amounts of protein and fat to precociously induce low, forager-like FAS activity levels in nurse-age bees deprived of protein. We speculate that reduced protein appetite and consumption during the nurse-forager transition is responsible for suppressed lipid synthesis in foragers.

An analysis of diffusion mechanism and mechanical properties of jute, JUCO, and banana fiber composites in three different mediums

Natural fiber-reinforced polymer composites (NFRPC) are the most desirable for their low-cost, eco-friendly, and high-durability properties. Scientists are facing numerous challenges with this type of composite in a wet or high-humid environment. High water absorption and reduced mechanical properties are the main concerns for this type of composite. A new kind of fiber mat called JUCO, which is a mixture of jute and cotton, is introduced here. Banana fiber and jute yarn were used to fabricate unidirectional mats, which were made using a custom-designed handloom. The composite fabrication was done by hand layup with the cold press method. The tensile and flexural strengths decreased after immersion in three mediums (pH 3, pH 7, and pH 8) for 150 days due to the water aging effect. Minimum strength was found when the samples were immersed in pH 3 mediums. Tensile and flexural test results were also evaluated by the finite elemental method (FEM) to validate the experimental results. The main objectives of this study are to investigate the mechanical properties and degradation due to the aging of newly developed JUCO fiber-based composites.

PSX-4 Exploring the impact of age and body condition score on the genetic analysis of mature cow weight in American Angus cattle

Abstract Selecting sires with optimal genetic merit for mature weight (MWT) is crucial for profitability of beef producers, ensuring cost-effective production and increased economic returns per animal. The main objective of this study was to determine how different statistical approaches [e.g., including the fixed effects (FE) of age and body condition score (BCS) in the statistical model and/or pre-adjusting the weights for these effects] affect variance components estimation and genetic parameters for MWT, and their impact in the posterior selection decisions. The dataset provided by the American Angus Association (AAA) comprised 80,296 MWT records from 37,934 cows aged 2 to 15 yr. Contemporary groups (CG) were defined by concatenating herd, year, and season of measurement. Model 1 analyzed unadjusted MWT with CG and BCS as categorical FE and age as a covariable (quadratic). Model 2 was model 1 without BCS, model 3 was model 1 without age, and model 4 considered CG as the only FE. In model 5, MWT was pre-adjusted for 6 yr of age and BCS of 6, and CG was the only FE included in the statistical model. Additive genetic and permanent environment (pe) random effects were included in all statistical models except model 5, which did not include pe (only one adjusted record per animal). Variance components were calculated using REML implemented in the BLUPf90+ family of programs. Sires with at least 10 offspring (n = 1,483) were ranked according to their breeding values (EBVs) predicted for MWT, and all and the top 10% sires were used to estimate the rank correlation across models. The heritability (± SE) estimated for MWT was 0.43 (± 0.011), 0.42 (± 0.011), 0.70 (± 0.008), 0.72 (± 0.082), and 0.37 (± 0.013) for models 1, 2, 3, 4, and 5, respectively. Repeatability values were 0.64, 0.67, 0.72, and 0.76 for models 1, 2, 3, and 4, respectively. The EBV ranks were highly correlated between models 1 and 2 (Top 10%: 0.96; All: 0.99), and models 3 and 4 (Top 10%: 0.99; All: 0.99). Inflated heritabilities in models 3 and 4 suggest that the effect of age is confounded with the additive genetic effect, which will not translate to greater genetic progress. Therefore, disregarding age in the genetic evaluation of MWT is not recommended. Similarities between models 1 and 2 suggest that BCS has a relatively small impact on MWT, probably related to the relatively low genetic correlation between these traits. Models 1 and 5 cannot be directly compared, as they use slightly different response variables (body weight vs. pre-adjusted weight) and may lead to slightly different selection decisions (correlation between Top 10%: 0.85; All: 0.95). Further investigations in this field are warranted.

A Machine Learning Approach for Efficiently Predicting Polymer Aging from UV-Vis Spectra.

This research has introduced an innovative approach that proficiently forecasts the alterations in ultraviolet-visible spectroscopy (UV-Vis) of polymer solutions during the aging effect. This method combines readily accessible feature descriptors with classical machine learning (ML) algorithms. Traditional spectral measurements, while precise in analyzing physical properties, are limited by their cost and efficiency. Therefore, this paper introduces a method that utilizes wavelength and the blue (B), green (G), and red (R) color values of the solutions as input features. We employed seven different ML models to train on these features with 10-fold cross-validation to ensure the reliability and generalizability of our results. After comparative analysis, all of the models performed excellently. Among them, the ExtraTree model demonstrated particularly high precision and excellent predictive ability on the testing set, with a Pearson correlation coefficient (r) of 0.9859 and a mean absolute error (MAE) of 0.0457. This study offers a practical solution for the rapid and cost-effective evaluation of polymer solutions' aging effect.

Copper excess in psychiatric disorders: a focus on mood spectrum disorders and sex

BackgroundMeta-analyses show increased copper (Cu) levels in major depression disorder. However, the association of Cu biomarkers with clinical classification in other mental health disorders has not been fully explored. MethodsTo this aim, we compared an extensive panel of Cu biomarkers, composed of Cu, ceruloplasmin (Cp) Cp activity, Cp specific activity, Cu not bound to ceruloplasmin (non-Cp Cu, also known as ‘free’ copper) in 171 consecutive patients affected by psychiatric disorders and in 61 healthy controls (HC) using MANOVA adjusting for the effect of sex and age, and studied their association with the clinical scale outcomes at psychiatric examination, namely Global Assessment of Functioning, Clinical Global Impression, and Brief Psychiatric Rating Scale. Resultsindividuals with psychiatric disorders were classified as 109 patients affected by mood spectrum disorders (MSD), 20 patients with schizophrenia spectrum disorders (SSD), and 42 with personality disorders (PD). Cu and non-Cp Cu were increased in psychiatric individuals than in HC, which also differed among the patients stratified per the clinical classification, being higher in the MSD individuals. The analysis stratified for sex revealed that women from the patient group, and specifically from the MSD group, had increased levels of Cu and non-Cp Cu than healthy women, while no difference was revealed in men. A logistic regression model considering the effect of sex and age revealed that non-Cp Cu could explain 26 % increased odds of having MSD per µmol/L unit increase (OR = 1.26; p = 0.0008; 95 % CI 1.099–1.436), that reached 40 % when considering only women. This result was driven by non-Cp Cu that correctly classified 64.1 % MSD (70 % in women) individuals vs. HC in a decision tree model, with values higher than 2.1 µmol/L which could distinguish the majority of MSD patients (86.3 % MSD vs. 13.7 % HC in women). None of the biological variables under study correlated with outcomes of the clinical scales, substances, or alcohol abuse. ConclusionCurrent results suggest mild Cu toxicity in women with MSD, as revealed by a value of non-Cp Cu higher than 2.1 µmol/L, which can be further investigated to assess its potential diagnostic accuracy in bigger and longitudinal cohorts.

PREVALENCE OF PAROTID TUMORS AMONG YEMENI PATIENTS IN SANA'A CITY, YEMEN

Background and aims: Parotid gland tumors (PGT) are a moderately scarce group of tumors with a broad range of histopathological manifestations and clinical characteristics. To date, most epidemiological studies on salivary gland tumors including PGT are limited in Yemen and this is one of the first studies, so the aim of the study was to determine the prevalence of different tumors affecting the parotid glands and the effect of age and sex on their distribution. Methods: Epidemiological information as well as demographic data, anatomical site, and histological analysis of PGT were analyzed. The data analyzed included age, sex, site, and histological diagnosis. Data were collected from all histopathological centers covering the majority of Sana'a city between 2019 and 2023. Results: A total of 284 cases- 69% benign and 31% malignant tumors were examined. Both benign and malignant tumors showed a little male inclination (52.5%) and a peak occurrence between the third and fifth decade. Malignant tumors make up 31% of patients, while benign tumors make up 69%. Mucoepidermoid carcinoma (36.4%) and adenoid cystic carcinoma (11.4%) are two common malignant tumor types. Benign parotid tumors include pleomorphic adenoma (71.4%) and Warthin tumors (11.2%) of benigns. Other malignants and benigns are less frequent. Conclusions: This study presents the first prospective study to date to analyze PGT data from health centers spread across Sana'a city. These results should serve the same as the basis for prospect studies assessing the epidemiological geography of these tumors in Sana'a in particular and Yemen in general. Peer Review History: Received 18 May 2024; Reviewed 12 July 2024; Accepted 23 August; Available online 15 September 2024 Academic Editor: Dr. Nuray Arı, Ankara University, Turkiye, ari@ankara.edu.tr Average Peer review marks at initial stage: 6.5/10 Average Peer review marks at publication stage: 7.5/10 Reviewers: Asmaa Ahmed Mohamed Ahmed Khalifa, Pharos University, Alexandria, Egypt, asmaa.khalifa@pua.edu.eg Dr. George Zhu, Tehran University of Medical Sciences, Tehran, Iran, sansan4240732@163.com

Nuclear Magnetic Resonance (NMR) Assessment of Bio and Crude Oil-Based Rejuvenation

Asphalt binders in pavements lose their stability through aging and eventually fail in the field. Using nuclear magnetic resonance (NMR) to monitor the primary longitudinal relaxation time of asphalt samples and the ratio of material that carries this primary relaxation time has been shown to indicate the impact of ultraviolet (UV) radiation on the aging of asphalt pavements. Longitudinal NMR relaxation was used to investigate two types of proposed asphalt rejuvenators, a bio-oil-based rejuvenator and a crude-oil-based rejuvenator. Two different binders with the performance grades (PG) 64-22 and 76-22 were considered for their interactions with the rejuvenators. After 72 h of exposure to intense UV radiation, specifically designed NMR relaxometry experiments were applied to compare the rejuvenation capabilities of the two rejuvenator samples. The crude oil-based rejuvenator was found to exhibit relaxation times similar to the binder samples while the bio-based material showed relaxation times that pointed to different nuclear hydrogen environments. Both rejuvenators reduced the primary relaxation time of the PG 76-22 binder, which indicates that their stiffness was reduced. Both types of rejuvenators also seemed to prevent the effects of UV aging. Two mechanisms of rejuvenation were identified by NMR relaxometry. The primary relaxation time can be used to indicate a change in stiffness while the primary ratio of the material is tied to oxidative aging. Oxidative aging creates distinct hydrogen environments due to asphaltene aggregation. The bio-based rejuvenator only reduced the binder’s stiffness, while the crude oil-based rejuvenator also reduced the aggregation of asphaltenes. Consequently, the bio-based rejuvenator could be classified as an asphalt softener, while the oil-based material acted like a true rejuvenator.

The effect of direct aging treatment on microstructure and mechanical properties of the GH4099 superalloys produced by selective laser melting

The effect of direct aging (DA) treatment on microstructure and mechanical properties of the GH4099 superalloys produced by selective laser melting (SLM) was investigated by the microhardness tests, room- (RT) and high-temperature (HT) tensile tests, field emission scanning electron microscopy (FE-SEM), and electron backscattered diffraction (EBSD) in this study. Both microhardness and RT tensile results show that DA treatment improves mechanical properties more than solution-aging (SA) treatment. By analyzing the effect of the microstructural features on the yield strength, we found that the dominant strengthening mechanisms responsible for higher yield strength of the DA specimens are the grain size hardening of fine γ matrix, high-density dislocation strengthening, Orowan dislocation bypass strengthening of smaller but dense M23C6-type carbides, and chemical strengthening of smaller but dense γ΄ nanoprecipitates. Furthermore, a transgranular fracture is a dominant fracture type for RT tensile specimens produced by DA treatment. Conversely, the failure type of SA tensile specimens is a typical intergranular fracture mechanism. The underlying mechanism for the above phenomenon is attributed to the effects of transgranular and intergranular M23C6-type carbides.

The effect of aging on mast cell density in human skin: a comparative analysis of photoexposed and photoprotected regions.

Mast cells are mononuclear cells originating from bone marrow. They produce various biologically active substances, which allow them to actively participate in immune and inflammatory processes associated with intrinsic and extrinsic skin aging. This research focused on distribution and density of mast cells in healthy skin in different stages of skin aging. This project included samples of photoexposed and photoprotected skin, obtained from 90 cadavers aged 0-82 years. The samples were classified into five age groups: newborns, young age, middle age, senior age and the oldest age. In order to visualize the mast cells, we have employed several histochemical staining protocols. The number of mast cells of the photoexposed skin significantly correlated to the individual's age. The number of mast cells of the photoprotected skin was in general statistically significantly lower in younger compared to older groups; however, the correlation of the mast cell density in photoprotected skin and the age did not reach statistical significance. In middle age, senior age and the oldest age groups, a significantly higher number of mast cells was recorded in the skin of the photoexposed compared to photoprotected region. The increase in mast cell density correlated with age only in photoexposed skin. Age-related higher accumulation of dermal mast cells in photoexposed skin can be an important factor in the photoaging process, as well as the contributing factor in the occurrence of skin cancer.

New evidence of healthier aging: Positive cohort effects on verbal fluency

Abstract Background and Objectives Cross sectional studies have shown improvements in cognition in later born cohorts. However, it remains unclear whether these cohort effects extend beyond cognitive levels and are also detectable in the rate of age-related cognitive decline. Additionally, evidence is scarce on the presence and consistency of cohort effects throughout different segments of the distribution of cognitive trajectories. Research Design and Methods This study evaluates the existence and variability of cohort effects across the entire distribution of aging-related trajectories of verbal fluency. With this purpose, we develop sex and education adjusted longitudinal norms of verbal fluency using data from 9 waves of the English Longitudinal Study of Aging (ELSA) by fitting quantile mixed models. The effect of age was modelled using splines to assess birth cohort effects, after grouping individuals in five-year groups from 1920 to 1950 according to their age at study entry. To test for possible cohort effects across the 10th, 50th and 90th quantiles, the coefficients associated with the splines were allowed to vary among cohorts. Results Our results suggest that, consistently across longitudinal quantiles, decline in verbal fluency across age is less pronounced for later born individuals (p < 0.001), supporting the hypothesis of cohort effects. Additionally, we also found that quantiles of verbal fluency at any age are shifted upwards in later-born cohorts compared to those in earlier-born cohorts. Discussion and Implications These results enhance our understanding of cognitive decline in older adults by demonstrating that cohort effects on cognition are observable both cross-sectionally and longitudinally, impacting the entire range of verbal fluency trajectories.

Impact of Fenton aging on the incipient motion of microplastic particles in open-channel flow

Upon entering the environment, Microplastics (MPs) experience aging processes that modify their properties and integrity. Previous methods for predicting the incipient motion of MPs have been validated using pristine plastics, which do not account for the effects of aging. This can lead to uncertainties in both quantification and characterization. This study investigates the effect of aging on the incipient motion of MPs with different bed roughness (smooth and rough beds) and MP properties (e.g., grain sizes and densities) in an open-channel flow. Five types of MPs were subjected to four different degrees of aging using the Fenton reagent, and their incipient velocities were tested on beds with two distinct roughness. The results suggest that the incipient velocity of MPs increases linearly with aging. However, this increase is not uniform across different particles and bed roughness. Upon comparing various commonly employed sediment incipient velocity equations, experimental results are in agreement with Ruijin Zhang's equation as the most precise. The parameters in Ruijin Zhang's equation are modified to enhance its applicability for predicting the incipient velocity of aged MPs. This study provides novel insights into the incipient motion of aged MPs in an open-channel flow, highlighting the intricate interaction between aged MP characteristics and bed roughness.

Dynamic plastic deformation at liquid nitrogen temperature and aging effects on microstructure and properties of Cu-0.3Zr-0.15Cr alloys

The 9R phase is rarely formed in copper alloys because of its high stacking fault energy. In this study, we generated a large amount of 9R phase in Cu-0.3Zr-0.15Cr alloys by dynamic plastic deformation (DPD) at liquid nitrogen temperature for the first time, and revealed the transformation mechanism of 9R to nanotwins. The process of DPD + aging treatment enables the alloy to obtain excellent comprehensive properties (strength of 657 MPa, electrical conductivity of 75.2 % IACS, and elongation of 14.6 %), which are derived from the heterogeneous microstructure composed of ultrafine structures, coarse grains, and nano precipitated phases. In addition, we have evaluated the phase transformation kinetics after DPD at liquid nitrogen temperature. This work provides a new way to better understanding the microstructure transition and precipitation kinetics under dynamic plastic deformation with aging treatment at liquid nitrogen temperature.