Ionic fuel-powered hydrogel actuators for soft robotics.

HYPOTHESIS: Hydrogel actuators powered by chemical fuels are pivotal in autonomous soft robotics. Nevertheless, chemical waste accumulation caused by chemical fuels hampers the development of programmable and reusable hydrogel actuating systems. We propose the concept of ionic fuel-powered soft robotics which are constructed by programmable salt-responsive actuators and use waste-free ionic fuels. EXPERIMENTS: Herein, soft hydrogel actuators were developed by orchestrating the Janus bilayer hydrogels' capacity for swelling and shrinking. Decomposable and easily removable ionic fuels were applied to power the actuators. Swelling tests were used to evaluate the deformability of the hydrogels. Tensile tests were performed to investigate the modulus of the hydrogels. The bonded interface composed of the interpenetrating polymer chains from both hydrogel layers bilayer was evidenced by the optical microscopy and scanning electron microscopy. The ionic conductivities of solutions were determined by a conductivity meter. Furthermore, a range of biomimetic soft robots with various shapes and asymmetrical structures have been designed and fabricated to execute complex functions. FINDINGS: The programmable actuators powered by ionic fuel exhibit adjustable bending orientations, amplitudes, and durations, along with consistent cyclic actuations enabled by replenishment of the fuel without noticeable loss in performance. Many life-like programmable soft robotic systems were designed, indicating spatiotemporally controllable functions.

Spectroscopic assessments on Sm3+ ions doped phospho-borate glasses mixed with fluoride modifiers for the applications of reddish-orange visible light.

Sm3+ions doped Phospho-Borate glasses were synthesized and their physical and spectroscopic parameters were studied to evaluate its potential reddish-orange emission for photonic applications. Structural investigation made through XRD analysis confirms the amorphous nature. The evaluated bonding parameters from the absorption spectral analysis confirm the ionic bonding of the Sm-O network in the prepared glasses. Four emission bands were observed from the luminescence spectra, and the HT 4G5/2 → 6H7/2 is observed at 601 nm. The oscillator strength values elucidate the intensity of the absorption bands, and the PBKZnF:Sm sample exhibits a higher oscillator strength value. The Judd-Ofelt intensity parameters were observed to trail the trend Ω4 > Ω6. > Ω2 for the majority of the samples. The CIE 1931 color chromaticity investigation confirms that the present glass samples are suitable for reddish-orange media. Barium and strontium-incorporated glasses exhibit outstanding lasing potential, which was confirmed through the efficiency of the quantum yield and some of the radiative parameters like effective bandwidth, transition probability and stimulated emission cross-section. Radiative parameters have been calculated from the luminescence spectra. Amid all transitions, 4G5/2 →6H7/2 transition has higher transition probability and higher stimulated emission cross-section values for all the prepared glass samples. Barium-incorporated glass exhibits a higher emission cross-section of 30.55 × 10-22 cm2 and a transition probability of 30.89 s-1 compared to all other glasses. The non-exponential decay profiles of the fabricated samples were plotted by examining the excitation wavelength at 402 nm and emission wavelength at 600 nm. Of all the prepared glasses, the quantum efficiency is found to be higher for the glass sample PBKSrF:Sm (65 %).

A supramolecular hydrogel leveraging hierarchical multi-strength hydrogen-bonds hinged strategy achieving a striking adhesive-mechanical balance.

To obtain high-performance tissue-adhesive hydrogel embodying excellent mechanical integrity, a supramolecular hydrogel patch is fabricated through in situ copolymerization of a liquid-liquid phase separation precursor composed of self-complementary 2-2-ureido-4-pyrimidone-based monomer and acrylic acid coupled with subsequent corporation of bioactive epigallocatechin gallate. Remarkably, the prepared supramolecular hydrogel leverages hierarchical multi-strength hydrogen-bonds hinged strategy assisted by alkyl-based hydrophobic pockets, broadening the distribution of binding strength of physical junctions, striking a canonical balance between superb mechanical performance and robust adhesive capacity. Ultimately, the fabricated supramolecular hydrogel patch stands out as a high stretchability (1500 %), an excellent tensile strength (2.6 MPa), a superhigh toughness (12.6 MJ m-3), an instant and robust tissue adhesion strength (263.2 kPa for porcine skin), the considerable endurance under cyclic loading and reversible adhesion, a superior burst pressure tolerance (108 kPa) to those of commercially-available tissue sealants, and outstanding anti-swelling behavior. The resultant supramolecular hydrogel patch demonstrates the rapid hemorrhage control within 60 s in liver injury and efficient wound closure and healing effects with alleviated inflammation and reduced scarring in full-thickness skin incision, confirming its medical translation as a promising self-rescue tissue-adhesive patch for hemorrhage prevention and sutureless wound closure.

Decoding Information Flow and Sensory Pollution: A Systematic Framework for Understanding Species Interactions.

Information transmission among species is a fundamental aspect of natural ecosystems that faces significant disruption from rapidly growing anthropogenic sensory pollution. Understanding the constraints of information flow on species' trophic interactions is often overlooked due to a limited comprehension of the mechanisms of information transmission and the absence of adequate analytical tools. To fill this gap, we developed a sensory information-constrained functional response (IFR) framework, which accounts for the information transmission between predator and prey. Through empirical evaluation, the IFR provided a biologically grounded explanation for the systematic variation of functional responses. Specifically, it posits that the variation of different functional-response shapes, associated with community stability, is attributable to limitations in sensory information transmission among species. This not only deepens our mechanistic understanding of species interactions but also elucidates how anthropogenic activities are reshaping species interactions and community dynamics by disrupting information exchange through sensory pollution.

Curving-Stretching Induced Alignment in Hydrogel Actuators for Enhanced Grip Strength and Rapid Response.

Natural tissues, like ligaments and tendons, display not just robust mechanical performance but also complex anisotropic structures extending beyond one-directional arrangements. However, fabricating hydrogel actuators with biomimetic three-dimensional anisotropy remains challenging. Herein, a simple strategy involving curving-stretching induced alignment is proposed to prepare anisotropic Fe3+-cross-linked poly(acrylic acid)-poly(acrylamide) hydrogel actuators. These hydrogels exhibit exceptional mechanical properties, boasting a fracture stress of 7.1 MPa and a superior modulus of 33.2 MPa when prestretched to 200% strain, which are 2.3 times and 4.9 times higher than their unstretched counterparts. The stretched anisotropic hydrogel gripper, stronger than its unstretched counterpart, can lift heavy objects while also achieving rapid responsiveness to stimuli. This work introduces a novel and effective method for fabricating anisotropic hydrogels, highlighting their broad applicability in fields such as soft robotics, biomedical devices, and beyond.

Utilization of quarry dust and periwinkle shell ash in concrete production.

The usage of plentiful raw discarded resources in the manufacturing of concrete has proven to be a sustainable and environmentally beneficial method of making concrete for a variety of purposes. In this study, the physical and mechanical properties of concrete made by partially and fully substituting fine aggregates and ordinary Portland cement with periwinkle shell ash and quarry dust (5%, 10%, 15%, 20%, and 100%), respectively, were examined. The ratio of water to cement utilized for the concrete mixture, 1:2:4, was 0.60. Fresh concrete underwent a slump test, and then 150-mm cubes of cured concrete were subjected to density, compressive strength tests, and morphological and structural property characterizations. The concrete without the waste materials gave an optimum compressive strength of 22.9 N/mm2 as opposed to those that were partially replaced, having 18.8-15.1 N/mm2. The concrete samples with full replacements of periwinkle shell ash and quarry dust have compressive strengths lower than 13.8 N/mm2. All the concrete samples produced with partial and full replacements are in the class of normal concrete, but only those with partial replacements of up to 20% can be utilized for load-bearing and non-load-bearing applications. Opting for these alternative waste materials implies taking steps towards creating a cleaner and healthier planet for now and the future.

Average optimal minimum velocity threshold: A practical variable to increase the accuracy of one-repetition maximum estimation during the free-weight back squat.

The prediction of one-repetition maximum (1RM) using the submaximal load-velocity relationship (LVR) is highly relevant for the field of strength and conditioning. The optimal minimum velocity threshold (MVT) was recently proposed to increase the accuracy of 1RM predictions. However, using the average optimal MVT would allow for more practical estimations. LVRs of the free-weight back squat were obtained in 53 participants, throughout 2 sessions. LVRs were obtained using the multi- and two-point methods. Estimations of 1RM were made based on the average actual MVT (1RM velocity) and the average optimal MVT. The accuracy of 1RM predictions was examined using absolute-percent error and Bland-Altman plots. Cross-validation was performed using a leave-one-out approach. The number of selected loads did not affect the slope, y-intercept, optimal MVT or the accuracy of 1RM predictions. Predictions based on the average optimal MVT displayed greater accuracy than those obtained with the average actual MVT (~6% vs. ~8% absolute-percent error, respectively). However, wide 95% limits of agreement (LoA) were found between actual and estimated 1RM using both approaches (~13%1RM). The average optimal MVT offers more accurate 1RM estimations than the average actual MVT. However, errors prove substantial, making it challenging to precisely track minor changes in 1RM.

Investigation of the appropriate thread depth for bioabsorbable screws.

The relatively low strength of bioabsorbable screws is a critical clinical issue. A shallower thread depth will increase a screw's strength, but the pull-out strength of the screw will decrease proportionally with the thread depth. We sought to provide further clarification of the relationships between (i) the thread depth and the pull-out strength, and (ii) the minor diameter and the shearing and bending strengths in bioabsorbable screws made of uncalcined and unsintered hydroxyapatite particles and poly-L-lactide (u-HA/PLLA). Seven types (thread depth from 0.1-0.7 mm) of screws with a major diameter of 4.5 mm were manufactured. Each screw type's pull-out strength was investigated using simulated bone. A shearing test and three-point bending test were both used to measure the physical strength of the screws. We then analyzed the relationships between the mechanical findings and the thread depth. The relationship between the thread depth and the pull-out strength showed a positive biphasic linear correlation with a boundary at 0.4-mm thread depth. The relationships between the minor diameter and both the shearing and bending strengths showed positive linear correlations within the range of dimensions tested. Within the scope of this study, a 0.4-mm thread depth proved to be an appropriate value that provides sufficient pull-out strength and screw strength for u-HA/PLLA screws with a 4.5-mm major diameter.

RESP-FIT: A Technology-Enhanced Combined Inspiratory and Expiratory Muscle Strength Training Intervention for Adults With COPD.

Background: Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disease associated with respiratory muscle weakness and activity-limiting symptoms such as dyspnea. Respiratory muscle strength training (RMST) is an empirically validated therapy to increase respiratory muscle strength. The theoretically-informed, technology-enhanced RESP-FIT intervention for COPD is a 6-week combined inspiratory and expiratory muscle strength training program with symptom measurement in real time via ecological momentary assessment (EMA). Objectives: In addition to hypothesis generating purposes, the purpose of this randomized control pilot study was to explore whether observed effects (on symptoms, patient-reported outcomes, and respiratory muscle strength) support carrying out a future large-scale trial of RESP-FIT. Methods: Thirty adults with COPD were randomized to intervention (n=15) or control, with intervention group undergoing 6 weeks of mHealth-enhanced RMST. Daily symptom data were collected in real time over the 6-week intervention period using EMA. Results: Compared to the control group, participants in the intervention group reported decreased dyspnea and anxiety, increased happiness, and improved respiratory muscle strength (PIMax). However, reports of fatigue and sleep disturbance increased in the intervention group compared to the control group. Conclusion: Results support the hypothesis that the 6-week RESP-FIT program will improve respiratory muscle strength, emotional state (anxiety and happiness), and breathlessness in COPD but may contribute to fatigue, at least in the short-term. Future work is needed to determine efficacy of RESP-FIT, determine mechanisms of action on dyspnea and fatigue, and conduct within-subject comparisons of EMA data to explore individual or environmental fluctuations in COPD symptoms.

STABILITY OF MEDIALLY AND LATERALLY MALPOSITIONED SCREWS: A BIOMECHANICAL STUDY ON CADAVERS.

BACKGROUND CONTEXT: Pedicle screw instrumentation is widely used in spine surgery. Axial screw misplacement is a common complication. In addition to the recognized neurovascular risks associated with screw misplacement, the biomechanical stability of misplaced screws remains a subject of debate. PURPOSE: The present study investigates whether screw misplacement in the lumbar spine reduces mechanical screw hold. STUDY DESIGN/SETTING: Cadaveric biomechanical study METHODS: Pedicle screw (mis)placement was planned for 12 fresh frozen cadaveric spines between the T12 and the L5 levels. The screws were then implanted into the vertebrae with the help of 3D-printed template guides. Pre- and post-instrumentation computed tomography (CT) scans were acquired for instrumentation planning and quantification of the misplacement. The instrumented vertebrae were potted into CT transparent boxes using Polymethyl methacrylate and mounted on a standardized biomechanical setup for pull-out (PO) testing with uniaxial tensile load. RESULTS: The bone density of all the specimens as per HU was comparable. The predicted pull-out force (POF) for screws medially misplaced by 2mm, 4mm, and 6mm was respectively 985 N (SD 474), 968 N (SD 476) and 822 N (SD 478). For screws laterally misplaced by 2mm, 4mm, and 6mm the POF was respectively 605 N (SD 473), 411 N (SD 475), and 334 N (SD 477). Screws that did not perforate the pedicle (control) resisted pull-out forces of 837 N (SD 471). CONCLUSIONS: Medial misplacement is associated with increased axial screw hold against static loads compared to correctly placed screws and laterally placed screws. CLINICAL SIGNIFICANCE: In clinical settings, the reinsertion of medially misplaced screws should primarily aim to prevent neurological complications while the reinsertion of lateral misplaced screws should aim to prevent screw loosening.

Inducing ipsilateral motor-evoked potentials in the biceps brachii muscle in healthy humans.

To assess reticulospinal tract excitability, high-intensity transcranial magnetic stimulation (TMS) has been used to elicit ipsilateral motor-evoked potentials (iMEPs). However, there is no consensus on robust and valid methods for use in human studies. The present study proposes a standardized method for eliciting and analysing iMEPs in the biceps brachii. Twenty-four healthy young adults participated in this study. Electromyography (EMG) electrodes recorded contralateral MEPs (cMEPs) from the right and iMEPs from the left biceps brachii. A dynamic preacher curl task was used with ~15% of the subject's one-repetition maximum load. The protocol included maximal compound action potential (M-max) determination of the right biceps brachii muscle, TMS hotspot determination, and four sets of five repetitions where 100% stimulator output was delivered at an elbow angle of 110° of flexion. We normalized cMEP amplitude by M-max (% M-max) and iMEP by cMEP amplitude ratio (ICAR). Clear iMEPs above background EMG were observed in 21 subjects (88%, ICAR = .31 ± .19). Good-to-excellent agreement (intraclass correlation coefficient [ICC] = .795-1.000) and low bias (.01-.08 mV and .60-1.11 ms) were demonstrated when comparing two different analysis methods (i.e. fixed time-window vs. manual onset detection) to determine the cMEP and iMEP amplitude and latency, respectively. Most subjects demonstrated clear iMEPs above background EMG triggered at a pre-determined joint angle during a light-load dynamic preacher curl exercise. Similar results were obtained when comparing a single-trial manual identification of iMEP and a semi-automated time-window data analysis approach.

Functioning of post-COVID-19 patients: a cross-sectional study at the outpatient clinic for long-term effects.

BACKGROUND: After COVID-19 infection, long-term impacts on functioning may occur. We studied the functioning of patients with post-COVID-19 condition (PCC) and compared them to controls without PCC. METHODS: This cross-sectional study consisted of 442 patients with PCC referred to rehabilitation at the Helsinki University Hospital (HUS) Outpatient Clinic for the Long-Term Effects of COVID-19, and 198 controls without PCC. Functioning was assessed with a questionnaire including WHODAS 2.0. Patients underwent physical testing including a hand grip strength test (HGST) and a 6-minute walking test (6MWT). Lifestyle was assessed by questionnaire and comorbidities were collected as ICD-10 codes from the HUS Data Lake on the HUS Acamedic platform. RESULTS: The WHODAS 2.0 average total score was 34 (SD 18) (moderate functional limitation) for patients with PCC and 6 (SD 8) (normal or mild limitation) for the controls. The disability was higher in all aspects of WHODAS 2.0 in patients with PCC. Bivariate binomial and multivariable regression analyses showed that the presence of comorbidities, anxiety, depression, and smoking predicted a WHODAS 2.0 score of 24 (moderate functional limitation) or above in the PCC group. The average 6MWT distance was 435 m (SD 98 m) in patients with PCC and 627 m (SD 70 m) in controls. HGST measurements showed no significant differences from controls. CONCLUSIONS: In conclusion, patients with PCC had significantly reduced functioning based on WHODAS 2.0 scores and the 6MWT results. Comorbidities, anxiety, depression, and smoking were associated with moderate or severe limitations in functioning. Findings support that PCC is multifactorial and requires a holistic approach to rehabilitation.

The post-COVID-19 condition (PCC) has been shown to negatively impact functioning, quality of life, and mental health, with cognitive and physical impairments being prevalent.This study found that patients with PCC had significantly reduced functioning compared to controls.Key factors predicting severe disability included comorbidities, smoking, and mental health issues like anxiety and depression.The reduced functioning in patients with PCC appears to be multifactorial and not only related to COVID-19 infection.

A Non-Weight Bearing Method for Measuring Hip Abduction Strength Overestimates Hip Abductor Muscle Fatigue During One-Leg Stance.

OCCUPATIONAL APPLICATIONSAssessing workers' strength capacities is a common practice prior to return to work following injury or illness, or assessing capabilities for strenuous jobs. Because it requires 50% or more of maximum strength capacity, hip abductor muscle strength is a strong predictor of both middle- and older-aged individuals' ability to reliably balance on one leg and of their risk of falls. Our results suggest subjects were able to augment their hip abductor moment during unipedal weight stance via gluteus maximus activity. Weight-bearing hip abduction strength measures are important for assessing worker capacity for jobs requiring reliable unipedal balance whether during lateral loading, while walking in gusty winds, on slippery footing or resisting lateral deck movements on board ship or train. Measurements of hip abductor strength should be made in a full unipedal weight bearing posture; non-weight-bearing measurements significantly underpredicted hip abductor strength as well as endurance.

Background: Unipedal stance time is a significant predictor of fall risk in middle- and older-aged individuals. Because muscle fatigue reduces muscle strength over a sustained contraction, muscle endurance time could limit maximum unipedal stance time. Purpose: We tested the hypothesis that hip abduction muscle endurance time, which depends on muscle strength, limits maximum unipedal stance time. Methods: We recruited 18 healthy young (10 females) and 17 older (10 females) adults who could stand on one leg for at least 10 s. Using a non-weight bearing test, we measured the left hip isometric maximum abduction strength and endurance time at 50% of that strength. We also measured subjects' maximum unipedal stance time, while force plate and full-body 3D motion capture signals were recorded. Subject-specific inverse dynamics biomechanical models were used to calculate the hip abduction moment required to stand on one leg. Results: Unipedal balance required a mean (SD) of 59 (19) % and 118 (53) % of the young and old adult hip abduction muscle strengths, respectively, which were consistent with published values. Mean (SD) hip muscle endurance times at 50% of abduction MVC were 63 (62) sec. and 147 (107) sec. for young and older adults, respectively. However, contrary to our hypothesis (above), the endurance time at 50% MVC failed to predict an upper limit for the maximum unipedal stance time. Conclusions: Our results show that standing on one leg requires over 50% of non-weight bearing hip abductor strength when young, and full strength when older. Because all younger individuals and four (out of 17) older individuals could balance on one leg longer than predicted during weight-bearing the gluteus maximus, a hip extensor, likely tensioned the iliotibial band to counteract abductor muscle fatigue with time. So, measurements of hip abduction strength should be made in the weight-bearing posture when middle- and older-aged workers' balance capacity is being assessed whether in a return-to-work assessment setting or evaluating workers for jobs requiring significant lateral loading, walking in gusty winds or on slippery surfaces, or on boat or train decks prone to sudden movements.

p38α kinase governs muscle strength through PGC1α in mice.

AIMS: Skeletal muscle, with its remarkable plasticity and dynamic adaptation, serves as a cornerstone of locomotion and metabolic homeostasis in the human body. Muscle tissue, with its extraordinary capacity for force generation and energy expenditure, plays a fundamental role in the movement, metabolism, and overall health. In this context, we sought to determine the role of p38α in mitochondrial metabolism since mitochondrial dynamics play a crucial role in the development of muscle-related diseases that result in muscle weakness. METHODS: We conducted our study using male mice (MCK-cre, p38αMCK-KO and PGC1α MCK-KO) and mouse primary myoblasts. We analyzed mitochondrial metabolic, physiological parameters as well as proteomics, western blot, RNA-seq analysis from muscle samples. RESULTS: Our findings highlight the critical involvement of muscle p38α in the regulation of mitochondrial function, a key determinant of muscle strength. The absence of p38α triggers changes in mitochondrial dynamics through the activation of PGC1α, a central regulator of mitochondrial biogenesis. These results have substantial implications for understanding the complex interplay between p38α kinase, PGC1α activation, and mitochondrial content, thereby enhancing our knowledge in the control of muscle biology. CONCLUSIONS: This knowledge holds relevance for conditions associated with muscle weakness, where disruptions in these molecular pathways are frequently implicated in diminishing physical strength. Our research underscores the potential importance of targeting the p38α and PGC1α pathways within muscle, offering promising avenues for the advancement of innovative treatments. Such interventions hold the potential to improve the quality of life for individuals affected by muscle-related diseases.

Comparison of bond failure with resin-modified glass ionomer cement and visible light-cured composite bonding systems in orthodontic patients: A split-mouth randomized controlled trial.

BACKGROUND: Resin-modified glass ionomer cement (RMGIC) is considered a fluoride-releasing bonding agent. OBJECTIVES: The aim of the study was to evaluate the rate of bracket bond failure with light-cured composite (LCC) and RMGIC, and to evaluate factors that contribute to the rate of bracket failure with both bonding agents. MATERIAL AND METHODS: A randomized controlled trial was conducted on a sample size of 33 patients. The patients were randomly allocated for bonding with visible LCC (control group) or RMGIC (intervention group) using the lottery method. The study was double-blinded. The rate of bracket bond failure was assessed after a follow-up of minimum 3 months and evaluated using the survival regression analysis, taking into account the effects of bonding agents and other factors influencing bracket bond failure. RESULTS: A total of 33 participants were recruited for the study, and 66 quadrants for the intervention and control groups were randomly selected and analyzed. The data was normally distributed and the mean age of the subjects was comparable between both bonding systems. The results of the regression analysis indicated that there was no statistically significant difference between the rate of bracket bond failure with RMGIC and LCC (p = 0.081). However, after analyzing the mean days of survival, it was found that bracket survival was negligibly low with RMGIC, with a mean of 216.00 ±133.72 days as compared to LCC, with a mean survival of 224.11 ±124.59 days. No adverse effects were observed during the course of the trial. CONCLUSIONS: There was no difference in the rate of bracket bond failure between the intervention and control groups. The survival rate of brackets treated with RMGIC was found to be comparable to that of LCC, with a minimal difference.

Individual and combined effects of muscle strength and visceral adiposity on incident prediabetes and type 2 diabetes in a longitudinal cohort of midlife Asian women.

AIM: To investigate the independent and combined effects of muscle strength and visceral adiposity on prediabetes and type 2 diabetes incidence among midlife women. MATERIALS AND METHODS: In this prospective study of midlife women (mean age 56.4 years), visceral adiposity, defined as visceral adipose tissue (VAT) >131 cm2 measured by dual energy X-ray absorptiometry, and poor combined muscle strength, defined as handgrip strength <18 kg and/or five-time repeated chair stand test performance ≥12 s, were determined at baseline between 2014 and 2016. After 6.6 years, the effects of VAT and muscle strength on risk of incident prediabetes (fasting blood glucose 5.6-6.9 mmol/L) and type 2 diabetes (fasting blood glucose levels ≥7 mmol/L, medication use, or physician diagnosis) were examined using modified Poisson regression analysis. RESULTS: Among the 733 initially normoglycaemic participants, 150 (20.5%) developed prediabetes or type 2 diabetes. Women with both poor combined muscle strength and high VAT had the highest risk for both prediabetes and type 2 diabetes (adjusted relative risk [aRR] 2.63, 95% confidence interval [CI] 1.81-3.82). In comparison, high VAT alone increased risk by 1.78-fold (95% CI 1.12-2.84). Stratification analyses showed that among women with low muscle strength, high VAT demonstrated increased risks of prediabetes and type 2 diabetes (aRR 2.84, 95% CI 1.95-4.14) compared to those with normal strength (aRR 1.66, 95% CI 1.04-2.65). CONCLUSIONS: Low combined muscle strength with high VAT poses a greater risk for the development of prediabetes and type 2 diabetes than high VAT alone. Muscle strengthening should be promoted alongside weight loss in diabetes prevention.

Evaluation of the Bond Strength of Acrylic Teeth to Denture Base after Various Chemical Surface Treatments: An In Vitro Study.

AIM: The purpose of the present study was to assess the bonding capacity and efficacy of acrylic teeth to denture bases following two different chemical surface treatments. MATERIALS AND METHODS: A two-metal mold measuring 35 mm in length and 12 mm in diameter was created specifically for the investigation in order to standardize the wax pattern-based tooth attachment at 45°. Following standard protocol, 75 wax cylinder specimens were flasked, dewaxed, and surface treatment of teeth was done as follows with 25 samples in each group-group I: control group, group II: monomethyl methacrylate monomer group, group III: acetone group. The curing process was completed following the packing of the denture base material. The samples' shear bond strength was assessed using a universal testing machine. Every sample was taken out when it fractured, and the shear load (Newton, N) was noted. The significance of the variation in applied shear load was assessed using one-way analysis of variance (ANOVA) and post hoc ANOVA Tukey's honestly significant difference (HSD) test at the 5% level of significance. RESULTS: The maximum shear bond strength was found in the samples treated with acetone (183.21 ± 0.06) followed by samples treated with monomethyl methacrylate monomer (171.64 ± 0.12) and the control group (149.32 ± 0.04). A statistically significant difference was found between the different groups (p < 0.001). CONCLUSION: In conclusion, according to the current study's findings, acetone chemical surface treatment of acrylic teeth produced the strongest bond when compared with the control group and monomethyl methacrylate monomer. CLINICAL SIGNIFICANCE: In prosthodontic practice, artificial teeth regularly de-bond and separate from the denture base. A weak interface is produced when certain clinical conditions, such as ridge prominence, cause excessive cutting of the acrylic teeth and base. Where the denture base polymer meets the teeth's highly cross-linked matrix, it de-bonds adhesively. Therefore, the bonding between the acrylic teeth and the denture base material can be improved by the chemical surface treatment. How to cite this article: Chaudhuri NG, Lahiri B, Francis NT, et al. Evaluation of the Bond Strength of Acrylic Teeth to Denture Base after Various Chemical Surface Treatments: An In Vitro Study. J Contemp Dent Pract 2024;25(6):514-517.

Effect of Adding Different Concentrations of Silver Nanoparticles on Flexural Strength and Microhardness of Different Denture Base Materials.

AIM: This study aimed to evaluate the effect of adding different concentrations of silver nanoparticles (AgNPs) on the flexural strength and microhardness of various denture base materials. MATERIALS AND METHODS: For this study, a total of 60 specimens were used and divided into equal groups. The first group consisted of heat-cured acrylic resin (Vertex-Germany), while the second group consisted of thermoplastic resin (Breflex 2nd edition, Germany). The samples were created using a split brass mold with dimensions of 65 × 10 × 2.5 mm, in accordance with the specifications of the American Dental Association (specifically No. 12 for flexural and microhardness). Following this, the samples were divided into three groups (A, B, and C) based on different concentrations of AgNPs (0, 2, and 5%). The flexural and microhardness of the samples were assessed using a universal testing machine and the Vickers hardness test, respectively. The data were gathered, organized, and analyzed using statistical methods. RESULTS: The flexural strength findings showed a significant difference between the two groups. Also, there was a considerable decrease in the average value of the acrylic group as the concentrations of AgNPs rose, while the flexural strength of the thermoplastic group notably improved. Regarding microhardness, the results showed a significant difference between the two groups. It showed that the mean value of both groups increased with increasing concentrations of AgNPs. CONCLUSION: Within the limitations of laboratory testing conditions of this study, it was discovered that AgNPs negatively impact the flexural strength of acrylic resins. Furthermore, an increase in the concentration of AgNPs was found to be directly related to the flexural strength of thermoplastic resin and the microhardness of both groups. CLINICAL SIGNIFICANCE: The concentration of AgNPs has a significant impact on certain mechanical properties of denture base materials, but it is important to consider their potential toxicity. How to cite this article: El-Hussein IG. Effect of Adding Different Concentrations of Silver Nanoparticles on Flexural Strength and Microhardness of Different Denture Base Materials. J Contemp Dent Pract 2024;25(5):417-423.

Does Taking a Break Matter-Adaptations in Muscle Strength and Size Between Continuous and Periodic Resistance Training.

We aimed to compare the effects of periodic resistance training (RT) and continuous RT on muscle strength and size. Fifty-five healthy, untrained participants (age 32 ± 5 years) were randomized to periodic (PRT, n = 20 completed the study, 45% females) or continuous (CRT, n = 22 completed the study, 45% females) groups. PRT completed a 10-week RT, a 10-week detraining, and a second identical 10-week RT. CRT began with a 10-week non-RT, followed by a 20-week RT. RT included twice-weekly supervised whole-body RT sessions. Leg press (LP) and biceps curl (BC) one repetition maximum (1RM), countermovement jump (CMJ) height, muscle cross-sectional area (CSA) of vastus lateralis (VL), and biceps brachii (BB) using ultrasound imaging were measured twice at the beginning and every fifth week during the intervention. Both groups increased (p < 0.001) 1RM in LP and BC, CSA in VL and BB, and CMJ height with no differences between the groups. In PRT, 1RM in LP and BC, CSA in VL and BB, and CMJ height decreased during detraining (p < 0.05). During the first 5 weeks of retraining in PRT, increases in LP 1RM, and VL and BB CSA were greater than in CRT during Weeks 10-15 of their CRT (p < 0.01). PRT and CTR ended up in similar postintervention adaptations, as decreased muscle strength and size during detraining in PRT regained rapidly during retraining. Our results therefore suggest that trainees should not be too concerned about occasional short-term training breaks in their daily lives when it comes to lifelong strength training. Trial Registration: ClinicalTrials.gov identifier: NCT05553769.

Impact of frenectomy on the oral exercise in patients with ankyloglossia and obstructive sleep apnea: double-blind randomized controlled clinical trials.

OBJECTIVE: This study compares the efficacy of oral exercise alone to oral exercise with frenectomy in improving obstructive sleep apnea (OSA) symptoms and quality of life (QOL) in patients with ankyloglossia. MATERIALS AND METHODS: A prospective, controlled, double-blind clinical study enrolled fifteen adults (20-60 years) newly diagnosed with mild to moderate OSA and ankyloglossia. Participants were randomly assigned to either oral exercise alone (control group; n = 8) or oral exercise with frenectomy (intervention group; n = 7). Outcomes were assessed after a 3-month therapy period using polysomnography, the Epworth Sleepiness Scale (ESS), tongue strength (measured in kPa), and QOL questionnaires. RESULTS: Both control (-2.88 ± 1.73; p = 0.02) and intervention (-4.00 ± 3.65; p = 0.03) groups showed a significant reduction in ESS scores, indicating both improved sleepiness. Although the apnea-hypopnea index (AHI) increased in both groups after treatment, these changes were not statistically significant (control 4.73 ± 15.55; p = 0.48, intervention 10.42 ± 14.66; p = 0.12). Tongue strength significantly increased in both groups: control group (p = 0.04) and intervention group (p = 0.03). Satisfaction rates with the overall treatment process were 100% in the control group and 57.1% in the intervention group. Furthermore, 75.0% and 57.1% of participants in the respective groups reported an improvement in QOL. CONCLUSION: Frenectomy improved tongue mobility and the ability to perform oral exercises in individuals with OSA and ankyloglossia. However, these exercises did not significantly improve OSA-related symptoms or QOL. CLINICAL RELEVANCE: While frenectomy enhances tongue mobility, thereby enabling better engagement in oral exercises. These exercises alone did not significantly improve OSA-related symptoms or QOL. This suggests that oral exercises focusing solely on tongue mobility may not be sufficient for managing OSA. TRIAL REGISTRATION: The Thai Clinical Trials Registry was TCTR20220429002.