Retention Test Research Articles

Treatment with Tinospora cordifolia ameliorates prenatal stress and maternal separation-induced memory deficits by restoring amygdaloid neuronal architecture

Introduction: Tinospora cordifolia (TC) possesses antioxidative properties and has been shown to improve cognition. In this study, the effects of TC were investigated on prenatal vibratory stress, maternal separation-induced amygdala plasticity, and memory retention in pregnant rats and their neonates. Methods: Four experimental animal groups of pregnant Wistar rats were employed in this research, including normal & vehicle controls, the stressed group, which received 3 hours of vibratory stress/day, and the TC-treated group, which received 6 mg/kg TC before vibratory stress. The neonates born to these mothers were then subjected to maternal separation, followed by postnatal TC treatment. After 6 weeks, the animals were assessed to evaluate memory retention, serum cortisol levels, and neuronal structural changes in the amygdala. Results: Neonates exposed to prenatal vibratory stress and maternal separation entered the dark compartment more quickly during the retention test (P<0.001), indicating reduced memory retention. In contrast, the TC-treated groups showed longer latencies (P<0.001), suggesting improved memory retention. The TC-treated mothers and neonates had longer dendrites with more branching points and intersections (P<0.001). However, these dendrites underwent pruning, indicating a complex structural response to stress and TC treatment. Conclusion: The results indicate that TC exerts neuroprotective effects against prenatal vibratory stress and maternal separation and aids memory retrieval in rats by restoring amygdala neuronal damage.

Manure‐biochar blends effectively reduce nutrient leaching and increase water retention in a sandy, agricultural soil: Insights from a field experiment

AbstractOrganic amendments are commonly applied singularly to soils to improve physical, biological and chemical properties, but their combination may be even more advantageous than when applied alone. In this study manure was applied singularly and in combination with biochar (90:10 and 50:50 ratios) to a drought prone agricultural Regosol in a field evaluation. Samples were collected twice a year for 2 years and subjected to testing for moisture retention, nutrient status and microbial activity whilst weed growth was monitored by drone. Substantial seasonal variability in all parameters measured was observed, though all amendments increased actual soil moisture content between 18 and 41% initially; without the addition of biochar (i.e., manure alone) this reverted back to reduced moisture content towards the second year of sampling. None of the tested amendment combinations significantly affected soil‐saturated hydraulic conductivity. Cation exchange capacity decreased as a result of manure addition alone, the addition of 10% biochar and 50% biochar increased this significantly (23%–54% increase). Though microbial biomass and enzyme soil health indicators showed no decisive changes as a result of amendment application, and plant biomass was variable by ground sampling, drone imagery proved that plant heights and health were generally increased as a result of biochar addition to manure, compared with manured soil alone. In summary, despite much field seasonal variability limiting the interpretation of the data, this study nonetheless demonstrates a useful maintenance of improved soil moisture achieved by adding biochar together with manure to a drought‐prone soil agricultural soil.

Production of Defragmentable Bioplastic using Starch Extracted from Annona Muricata (Soursoup) Seed Reinforced with Bentonite Nanoclay

Abstract Seeds of Annona Muricata, often called soursop or guyabano were used as a source of starch for the production of defragmentable bioplastic. The researchers used mixture of water and starch content of 10 and 20 grams respectively from Annona Muricata (soursop) seeds with various concentration (20%, 25%, 30%) of glycerol (plasticizer) and reinforced with three different concentrations (0%, 3%, 6%) of bentonite nanoclay (filler). The characterization of the bioplastic was carried out by determining the effect of variation of the ratio between the quantity of starch from soursop seeds, bentonite nanoclay, and glycerol. The starch-based defragmentable bioplastic was evaluated with its water retention, degradation, and mechanical properties. The result showed that the tensile strength improved significantly with the addition of bentonite nanoclay and the elongation at break with the addition of glycerol. Same way in water retention test, where the presence of the bentonite nanoclay increased the strength of the bioplastic with its water solubility. In soil burial test, a higher level of glycerol concentration increased the rate of the bioplastic degradation. By adding the bentonite nanoclay as a filler, the rate of bioplastic degradation decreased compared to the bioplastic without filler. In shelf-life test, adding glycerol as plasticizer improved the shelf life of bioplastics. A high concentration of glycerol served as an anti-fungal for bioplastics.

Comparison of lecture-based learning with presentation-assimilation-discussion method in occupational bloodborne exposure education of nursing students, a randomised trial

BackgroundOccupational Bloodborne Exposures (OBEs) are incidents where healthcare workers come into contact with blood or other potentially infectious materials, leading to risks of transmitting bloodborne pathogens. Nursing students, often in direct contact with patients, face heightened risks due to their duties.MethodsFirst, we conducted a cross-sectional survey using a OBEs questionnaire to explore the knowledge, attitudes, practices, and needs regarding OBEs among nursing students. Subsequently, we used a randomized controlled trial (RCT) to compare the impact of the Presentation-Assimilation-Discussion (PAD) method with the traditional lecture-based learning (LBL) method on OBEs education for nursing students. Pre-test, post-test, and retention test were used to observe the teaching effectiveness, and the students’ feedback on the teaching method was also observed.ResultsIn the cross-sectional survey, we found that nursing students lacked sufficient knowledge and management skills regarding OBEs but recognized the importance of standard precautions and expressed a desire for systematic OBEs training during their education and internships. In the RCT, the total, theoretical, and practical scores of the PAD and LBL groups were comparable in the pre-test (56.70 ± 3.47 vs. 56.40 ± 3.95, 33.09 ± 3.39 vs. 33.33 ± 2.44, 23.61 ± 4.66 vs. 23.07 ± 4.84, p > 0.05). After training, the PAD model demonstrated an advantage over the LBL model in immediate total (84.25 ± 4.06 vs. 78.95 ± 4.23, p < 0.001), theoretical (54.32 ± 2.43 vs. 51.44 ± 2.58, p < 0.001), and practical scores (29.93 ± 3.90 vs. 27.51 ± 4.33, p < 0.01). It also showed superior retention of total (69.05 ± 3.87 vs. 65.77 ± 2.94, p < 0.001) and theoretical scores (39.05 ± 3.05 vs. 36.23 ± 3.18, p < 0.001). However, there was no significant difference in the retention of practical scores between the two groups (30.00 ± 4.76 vs. 29.53 ± 3.73, p > 0.05). The PAD group benefited more across various learning dimensions but reported a higher study load.ConclusionsOur study reveals that the PAD model could be a valuable approach for teaching OBEs to nursing students.

Pet Attachment and Maintenance of Physical and Cognitive Function in Community-Residing Older Adults: Evidence From the Baltimore Longitudinal Study of Aging (BLSA)

ABSTRACT Pet ownership is associated with reduced deterioration in physical and cognitive function as older adults age. To date, little research focuses on whether the degree of attachment to the pet is related to the rate of deterioration in these functions. We examined the relationship of pet, dog, and cat attachment to changes in physical and cognitive function among 214 pet-owning, generally healthy, community-dwelling adults aged 50–100 years (M = 68.0, SD = 7.8) from the Baltimore Longitudinal Study of Aging (BLSA). Pet attachment was assessed using the pet ownership module administered during a regularly scheduled BLSA visit. Physical and cognitive assessments were administered every 1–4 years over 1–13 years (M = 7.5, SD = 3.6), including 400-meter walk time, usual and rapid-gait speed, Health ABC Physical Performance Battery, SF-12 Physical Component Score, California Verbal Learning (Immediate, Short, Long recall), Benton Visual Retention, Trail-Making (Trails A, B, B-A), Digit Span, Boston Naming (Naming), and Digit Symbol Substitution (Digit Symbol) Tests. In linear mixed models, controlling for age and comorbidities, greater pet attachment was associated with slower deterioration in physical performance (p = 0.009), usual-gait speed (p < 0.001), rapid-gait speed (p = 0.002), and executive function (Trails B: p = 0.005 and Trails B-A: p < 0.001), and faster deterioration in long-term recall (p < 0.001). Among dog owners (n = 121), a higher attachment was associated with slower deterioration in attention (Trails A: p = 0.046) and faster deterioration in short- (p = 0.025) and long-term (p = 0.019) recall. Among cat owners (n = 100), higher attachment was associated with a slower decline in physical wellbeing (p = 0.035). We provide important longitudinal evidence that pet attachment is differentially associated with the rate of decline in function older adults experience as they age and that attachment to different types of pets may have a different relationship to rates of decline. Potential explanations for these differences are proposed.

Quantitative Measures of Engagement in History Classes: Analyzing the Efficacy of Interactive Pedagogies

This study aimed to evaluate the impact of interactive pedagogy on student engagement and knowledge retention. A quantitative method was used. The sample was 500 students from three high schools. The Engagement measurement instrument and Knowledge Retention Test were used to measure engagement and knowledge retention metrics. Data collection was conducted over one semester. Data analysis used descriptive statistics, inferential, ANOVA, and Effectiveness Index. The results of this study confirmed that classroom activity engagement reached 88.32%, and history knowledge retention reached 80.30%, indicating the success of the pedagogical intervention. The Effectiveness Index of student engagement and knowledge retention was 35.70%.

The Effect of Internal and external imagery on learning badminton long serve skill: The role of visual and audiovisual imagery

This study aimed to examine the impact of internal and external audiovisual imagery on the learning of the badminton long serve skill. A lot of 42 right-handed novice women were selected using availability sampling. Participants were categorized into four groups based on their scores from the visual imagery ability questionnaire and Bucknell auditory questionnaire: Visual-Internal imagery, Visual-External imagery, AudioVisual-Internal imagery and AudioVisual-External imagery groups. To generate an auditory pattern, the shoulder joint’s angular velocity of a skilled individual was recorded and translated into sound based on frequency characteristic changes. Subjects underwent four sessions of 40 trials each and subsequently participated in retention and transfer tests. Performance accuracy of the badminton long serve was assessed using the Scott and Fox standard test and repeated measures ANOVA was employed to compare performance across groups during test stages. While no significant differences were noted between groups during the acquisition stages, indicated that subjects in the AudioVisual imagery conditions outperformed those in Visual imagery during the retention test. Additionally, the AudioVisual-Internal Imagery group demonstrated superior performance compared to other groups. Internal imagery groups also exhibited better performance in the later stages of acquisition, retention and transfer tests compared to external imagery groups. These findings suggest that the incorporation of audiovisual imagery utilizing movement sonification, alongside physical practice, improves skill development more effectively than visual imagery alone.

Open-field exploration immediately before the retention test impairs retrieval and spaced fear extinction of contextual fear memory

According to the behavioral tagging theory, various stages of fear memory, such as contextual fear conditioning, memory retrieval, and fear extinction, can be facilitated by the exploration of a novel open field (OF). A critical time window of efficacy exists for this process. Novel exploration closely adjacent to weak learning may interfere with the setting of the learning tag, leading to a negative effect. In this mouse study, we consistently showed that exposure to a novel or familiar OF immediately prior to the retention test impaired the retrieval of long-term contextual fear memory. However, OF exposure had no effect on the retrieval of recent or remote cued fear memory or short-term contextual fear memory or the reconsolidation of contextual fear memory. In addition, OF exposure impaired spaced but not massed extinction of contextual fear memory. These results suggest that interfering stimulus may result in the transient forgetting of fear memory; however, temporary loss of fear may lead to retention failure of fear extinction. The results of this study are an important complement to the behavioral tagging theory and may provide new guidance for the treatment of post-traumatic stress disorder.

Ecological-Dynamic Approach vs. Traditional Prescriptive Approach in Improving Technical Skills of Young Soccer Players.

Background: This study contributes to expanding the existing literature on learning technical skills in youth soccer by comparing the effectiveness of different training approaches in the development of passing skills. The ecological-dynamic approach, which emphasizes the continuous and adaptive interaction between the athlete and the environment, is analyzed in comparison to the traditional prescriptive approach, which relies on predefined techniques and exercises. The aim of the study is to determine which of the two approaches is more effective in improving the performance of young soccer players. Methods: Thirty players (age 12 ± 1.2 years) were randomly assigned to two groups: the ecological-dynamic group (ECG) and a control group (CON). Both groups underwent an eight-week training program with equal sessions. The ECG group's training focused on adjusting constraints like the learning environment, game rules, and visual restrictions to boost adaptability and problem-solving skills. The CON group followed a traditional prescriptive approach with specific instructions, goal setting, immediate feedback, and structured exercise progression. Passing abilities were evaluated before and after the program using the Loughborough Soccer Passing Test, with a retention test administered five weeks later. Descriptive statistics, including mean values and percentage improvements, were used. A repeated measures ANOVA compared differences between the groups. Results: The analysis revealed a significant Occasion × Group interaction for all performance variables, indicating that the ECG group experienced greater improvements than the CON group. Specifically, the ECG group showed significant reductions in Trial Time (p = 0.001, ηp2 = 0.6), Penalty Time (p = 0.016, ηp2 = 0.4), and Overall Performance (p = 0.011, ηp2 = 0.8) from pre-test to post-test. However, these improvements did not persist into the retention test (p = 0.131, p = 0.792, and p = 0.192, respectively). The CON group also improved significantly in Trial Time (p = 0.003), Penalty Time (p = 0.002), and Overall Performance (p = 0.001) from pre-test to post-test, but with smaller effect sizes and no sustained gains at retention. Conclusions: The ecological-dynamic approach (EDG) has proven to be more effective in enhancing passing skills compared to the traditional prescriptive approach (CON). Although both methods led to performance improvements, the EDG group achieved more significant progress.

Acai Oil-Based Organogel Containing Hyaluronic Acid for Topical Cosmetic: In Vitro and Ex Vivo Assessment.

Organogels are semi-solid pharmaceutical forms whose dispersing phase is an organic liquid, for example, an oil, such as acai oil, immobilized by a three-dimensional network formed by the gelling agent. Organogels are being highlighted as innovative release systems for cosmetic active ingredients such as hyaluronic acid for topical applications. Acai oil was evaluated for its physicochemical parameters, fatty acid composition, lipid quality index, spectroscopic pattern (Attenuated total reflectance Fourier Transform Infrared Spectroscopy), thermal behavior, total phenolic, total flavonoids, and total carotenoids and β-carotene content. The effectiveness of the organogel incorporated with hyaluronic acid (OG + HA) was evaluated through ex vivo permeation and skin retention tests, in vitro tests by Attenuated total reflectance Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry. The physicochemical analyses highlighted that the acai oil exhibited quality standards in agreement with the regulatory bodies. Acai oil also showed high antioxidant capacity, which was correlated with the identified bioactive compounds. The cytotoxicity tests demonstrated that the formulation OG + HA does not release toxic substances into the biological environment that could impede cell growth, adhesion, and efficacy. In vitro and ex vivo analyses demonstrated that after 6 h of application, OG + HA presented a high level of hydration, thermal protection and release of HA. Thus, it can be concluded that the OG + HA formulation has the potential for physical-chemical applications, antioxidant quality, and potentially promising efficacy for application in the cosmetic areas.

Comparison of Effects of Implicit versus Explicit Learning of a Novel Skill in Young Gymnastic Athletes.

The purpose of this study was to compare the effects of explicit learning with implicit learning using a dual-task paradigm on learning a novel skill and whether the performance was maintained over an extended period. Forty-four young children from a local gymnastics club (n = 44, boys n = 10, girls n = 34, age: 10 ± 2.9 years) completed four 30 min front-flip practice sessions over four weeks between pre- and post-test, followed by two retention tests three and six months after the post-test, in which no front-flip practice occurred. Comparable improvements were found beyond baseline performance for both learning conditions over the six-month hiatus. While both groups increased performance at the post-test, neither explicit nor implicit learning groups were able to maintain the achieved performance level into six months of retention. In particular, the explicit group showed a more marked decrease than the implicit group after three months, which was probably caused by the decay of their reliance on the retrieval of declarative knowledge from working memory. The current findings highlight the importance of conducting retention tests over an extended period to monitor performance development after the acquisition of a novel task by different learning methods, as they can differ over time.

The Role of Digital-Game Based Language Learning in EFL Vocabulary Learning and Retention: A Case Study at a Higher Educational Institute in Oman

This study investigates the role of Digital-Game Based Language Learning (DGBLL) in helping students learn and retain English vocabulary items in a foreign language context. Using a quantitative approach, data was collected from 80 students enrolled in four different levels of the General Foundation Program at the University of Technology and Applied Sciences, Ibra, Oman. The students were exposed to practice learning the meaning of ten vocabulary items per level using Kahoot and Wordwall games. Three tests were administered: a pre-test in week 1, a post-test after practicing the vocabulary items using the previously mentioned digital games in week 4, and a retention test in week 6. In addition, students’ perceptions regarding the efficacy of DGBLL in the vocabulary learning process were measured via a questionnaire following the post-test. The findings indicated the students’ positive attitudes in terms of utilizing DGBLL as a learning approach to mastering vocabulary regardless of gender or class level. Additionally, the findings demonstrated the effectiveness of DGBLL in vocabulary learning and retention. Hence, the study recommends using digital games to promote vocabulary learning and retention, resulting in a more engaging foreign language educational environment.

Evaluation of The Flipped Classroom Model on Students' Academic Achievement and Retention in MAN 1 Ambon

This study evaluates the impact of computer simulation and animation instructional packages in natural sciences on high school student's academic achievement and retention in a flipped classroom setting. Using a quasi-experimental pre-test and post-test design, 30 students used the computer simulation package, and 29 students used the computer animation package. Data were collected via academic achievement and retention tests and analyzed using descriptive statistics and independent sample t-tests. The results showed significant improvements in academic achievement for both groups. The average post-test score increased from 28.52 to 70.35 in the computer simulation group and from 25.74 to 64.23 in the computer animation group. The t-test indicated no significant difference in academic achievement between the two groups (t = 1.98, p = 0.79). Retention scores showed a slight decrease from post-test to retention test but remained high, with average retention scores of 68.74 for the simulation group and 61.15 for the animation group. The t-test also revealed no significant difference in retention between the groups (t = 1.12, p = 0.66). The implications of this study suggest that using educational technology, such as computer simulations and animations, in a flipped classroom setting can significantly enhance students' academic achievement and knowledge retention. It underscores the importance of integrating technology into the educational curriculum to create a more inclusive, interactive, and effective learning environment. Additionally, these findings allow educators to choose the teaching methods that best suit their instructional needs and contexts, whether in resource-limited situations or when teaching complex concepts.

The Impact of Two-Stage Testing and Other Tutorial Co-Learning Activities on Cohort Cohesion and Learning Outcomes in a Large-Enrollment Undergraduate Course

Large enrollments in undergraduate courses pose several teaching and learning challenges that impact students’ learning experience and performance. Implementing co-learning activities in tutorials of large courses can help mitigate these challenges and improve the learning environment. One type of collaborative learning activity that has become increasingly popular is two-stage testing but there are limitations to how two-stage testing has been conducted. We undertook a study to elucidate whether our modified two-stage testing protocol and other co-learning activities performed in tutorials can enhance the learning experiences of undergraduate students and foster a sense of community in a large-enrollment research methods course. The specific aims of our study were to: 1) Assess whether co-learning activities including two stage testing in tutorials improves learning outcomes and fosters cohort cohesion in a large-enrollment junior undergraduate science course. 2) Evaluate the impact of our modified two-stage testing approach on student learning and long-term retention. To assess cohort cohesion students were asked to complete a survey and were invited to participate in focus groups. Results indicated that tutorials did foster cohort cohesion among students in the tutorial. The tutorial activities helped scale down the course size and connect with their peers. We tested our modified two-stage testing protocol by administering a two-stage test (an individual test consisting of short-answer questions followed by a group test that was comprised of a subset of the individual test questions that was completed during tutorials). Approximately three months after the individual test, a retention test was administered. Student grades were significantly higher in group tests compared to the individual tests. Interestingly, students on average scored 6.2% higher on the retention test questions that were from the group test, compared to questions that were only on the individual test. These results support the idea that group tests help improve student retention. Students reported tutorials and two-stage testing to be a positive learning experience.

Effects of repeated unihemispheric concurrent dual-site tDCS and virtual reality games on motor coordination of sedentary adolescent girls

BackgroundThis study investigated the effects of repetitive unihemispheric concurrent dual-site anodal transcranial direct current stimulation (a-tDCSUHCDS) associated with the use of virtual reality games (VR) on the motor coordination of sedentary adolescent girls.MethodsThirty-six inactive adolescent girls were randomly assigned into 3 groups (n = 12 per group): (1) VR + a-tDCSUHCDS, (2) VR + sham-tDCSUHCDS, and (3) Control. The VR + a-tDCSUHCDS and VR + s-tDCSUHCDS groups received the intervention three times a week for four weeks. In each experimental session, participants first received either 20 min of a-tDCSUHCDS (2 mA at each anodal electrode) targeting the primary motor cortex (M1) and the left dorsolateral prefrontal cortex (DLPFC) or sham and then performed VR for 1 h. The control group received no intervention. Eye-hand coordination (EHC) and bimanual coordination (BC) were measured at baseline, post-intervention, and two weeks later (retention test) using the automatic scoring mirror tracer and continuous two-arm coordination test, respectively.ResultsResults showed that the EHC was significantly higher in the VR + a-tDCS and VR + s-tDCS groups at post-intervention (all ps< 0.001) and the retention test (all ps< 0.001) compared to the control group. Moreover, the EHC was significantly higher in the VR + a-tDCS group compared to the VR + s-tDCS group (p = 0.024) at the retention. Similarly, VR + a-tDCS and VR + s-tDCS improved BC compared to the control group at post-intervention (all ps< 0.001) and retention test (all ps< 0.001). In addition, higher BC was observed in the VR + a-tDCS group compared to the VR + s-tDCS group (p< 0.001) at the retention test.ConclusionsOur results suggest that adding a-tDCSUHCDS to VR over 12 sessions may have an additional effect on VR training for improving and retaining motor coordination in sedentary adolescent girls.

The Effect of In-person and Online Training on Learning Jump Rope Skills in Girl Students

Background: In situations with physical limitations, combining online and in-person methods with a greater focus on practical exercises, feedback, and maintaining motivation and commitment to learning may be the best approach. Objectives: The aim of the present study was to compare the effectiveness of two educational methods— in-person training and online training— on learning jump rope skills. Methods: Forty fourth-grade girl students were randomly assigned to two groups: In-person training and online training. Initially, participants took a pre-test that involved performing the basic single jump technique (BSJT) for 30 seconds. The online class was conducted on Iran's official educational platform, a messaging service that allows for the transmission of audio, video, and text files, as well as live calls. The in-person group received all instructions with the same content in person. Immediately after completing eight 45-minute instructional sessions, a post-test similar to the pre-test was administered. One week after the acquisition sessions, a retention test for 10 other jump rope techniques was conducted within a 30-second time frame, and the average score was calculated for each participant. Results: The results showed a significant main effect of the group, with the overall performance of the in-person group being better than that of the online group. Participants' scores in BSJT improved from the pre-test to the post-test. A significant difference was observed between the in-person and online groups in the retention test. Conclusions: In-person training appears to be generally more effective than online training for improving jump rope skills. While online training can be effective for mastering and consolidating previously learned skills, in-person training is preferable for learning and mastering more complex techniques.

Motivation Unraveled: Giving Choice to Football Players to Improve Anterior Cruciate Ligament Injury Prevention.

Benjaminse, A, Nijmeijer, EM, Gokeler, A, Broekhaar, DC, and Cortes, N. Motivation unraveled: giving choice to football players to improve anterior cruciate ligament injury prevention. J Strength Cond Res XX(X): 000-000, 2024-Providing athletes some control over a training session facilitates motor skill acquisition. This is a promising concept to use in anterior cruciate ligament (ACL) injury prevention, as the key for risk reduction is to improve quality of movement. The goal of this study was to better understand why improved motor learning occurred when football players had the opportunity to choose when to receive feedback when practicing sidestep cutting (SSC) movements. Healthy male recreational football players (n = 22, 22.9 ± 1.7 years, 185.5 ± 7.2 cm, 79.3 ± 9.2 kg) were included and assigned to the self-control (SC) or the yoked (YK) group. The players performed anticipated and unanticipated SSC. They received video instructions and were instructed to "copy the movement of the model to the best of their ability." During the training blocks, the SC group could ask for feedback, whereas the YK group could not. Cutting movement assessment scores (CMAS) were measured to test quality of movement and the Intrinsic Motivation Inventory was administered to measure constructs of motivation. In the anticipated condition, SC group showed better scores in immediate post and the retention test compared with pretest (p < 0.001), whereas the YK group showed worse scores in the retention test compared with immediate posttest (p = 0.001). Perceived competence (p = 0.017) and self-efficacy (p = 0.032) were consistent factors that correlated with improved CMAS in the SC group. This has given us innovative insights into underlying mechanisms optimizing the quality of movement, necessary to improve current ACL injury prevention approaches.

Sustainable and Robust Cellulose‐Based Core–Shell Hydrogels Recycled from Waste Cotton Fabrics as High‐Performance Food Coolants

AbstractIdeal temperature condition is one of the essential determinants that critically impact the quality of food products. Conventional water‐based ice cubes present challenges from meltwater being breeding grounds for microorganisms and heightening the risk for cross‐contamination. Hereby, the presented cellulose‐based hydrogels crosslinked by epichlorohydrin are dip‐coated with alginate/calcium chloride to form a core–shell structure for achieving the critical benchmarks of an ideal food coolant with limited meltwater production, high‐water retention capacity, and high mechanical strength. The structures and properties of the hydrogels before and after freeze–thaw cycles are characterized by scanning electron microscopy, compressive test, water retention test, and differential scanning calorimetry. All formulated hydrogels demonstrate promising compressive strength, latent heat of fusion, and water retention properties. Notably, the C2A10Cl hydrogel exhibits a maximum compressive strength of 144.7 kPa and high latent heat of fusion of 272.5 J g–1, which is better than previously reported sustainable hydrogel coolants. Furthermore, comparison studies reveal that the cellulose‐based hydrogels demonstrate a similar thawing pattern to conventional ice cubes but without the generation of any meltwater. The temperature of blueberries can be cooled down from 22 to 3.9 °C in 32 min by the hydrogels and in 26 min by ice cubes, respectively.

Enhancement in Formation of Insoluble Arsenic Phases without Re-Leaching by Particle Size of Excavated Sediment with Iron Sulfate Heptahydrate

ABSTRACT Massive quantities of naturally arsenic-containing sediments are excavated for construction. Chemical immobilization is applied to such excavated materials for reuse. Appropriate physicochemical properties should be understood to enhance the formation of the insoluble arsenic phases without re-leaching. The up-flow column retention test flowing 10 mg L−1 of arsenic solution was conducted to understand how the retention of arsenic and the phases of arsenic immobilized by iron sulfate heptahydrate depend on the particle size of the excavated sediment. The amount of arsenic retained on the immobilization material (particle size of 0.5 mm) during the retention test was lower for the larger particle size of the excavated sediment. However, arsenic was more stably retained on the immobilization material for the large particle sizes (1.0–2.0 and 2.0–5.0 mm) and the amount of arsenic re-leached was 12% of that in the small one (<0.5 mm). The percentages of arsenic in fraction 3 of sequential extraction increased from 45% to 68% with increasing the particle size. These results indicate that the excavated sediment with a larger particle size than that of immobilization material retains less arsenic on the immobilization material, but the arsenic phases immobilized are more stable, resulting in less arsenic re-leaching. This study suggests that the use of excavated sediment with a particle size larger than that of the immobilization material is desirable for the application of immobilization technique without re-leaching.

Comparison of Homogeneous and Heterogeneous Live and Video Models Observation on Basketball Dribbling and Shooting Skills in 13-15-Year-Old Females

Context: In recent years, there has been various research on observational learning and its different characteristics and methods through live and video models. Objectives: In this regard, the aim of the current research was to compare the observation of live and video models of the the homogeneous or heterogeneous on basketball dribbling and shooting performance. Methods: Forty-eight 13 - 15-year-old (14 ± 2) female students were randomly assigned into four groups (observing a live female model, a live male model, a female video model, and a male video model). The research was conducted in three phase: (1) pre-test, (2) post-test, and (3) retention test. In the pre-test, the subjects of all four groups performed the dribble and basketball shot test, then observed the implementation of these skills in one of the four models according to the group they were in. After observing the model, the individuals in each group were given a post-test and a retention test after 24 hours. Results: The results showed that in both dribbling and shooting skills, observing the live man model had a greater effect on the acquisition and learning of skills, whereas observing the video models of both men and women had no significant effect on the acquisition and learning of the desired skills. Conclusion: The results showed us that observing a live model is better than a video model, and a model of the opposite sex is more effective than a model of the same sex for femals.