Weakness Research Articles

The effect of early mobilization on complications after chronic subdural hematoma surgery

Aims: Chronic subdural hematoma is a common condition in the elderly population that often requires hospitalization. While some patients are discharged without surgery, others require surgical intervention due to symptoms such as loss of strength and consciousness. Preventing postoperative complications is as important as the surgical procedure itself. Early mobilization facilitate patients’ return to routine daily life, thereby reducing complications associated with immobility. This study will examine the effect of early mobilization on postoperative complications. Methods: This study included 34 patients diagnosed with chronic subdural hematoma who underwent surgical intervention at our institution between 2020 and 2024. Data collection encompassed findings from preoperative and postoperative neurological examinations, comorbid conditions, the extent of midline shift, time to postoperative mobilization, duration of intensive care unit stay, length of ward stay and overall hospitalization, as well as the incidence of postoperative complications. Patients in satisfactory general condition commenced oral feeding on the morning following surgery and were monitored under controlled conditions. The patients were divided into two groups: those who were mobilized and those who were not. These groups were then compared in terms of time to mobilization, postoperative complications, length of hospital stay, and mortality rates. Results: A comparison of postoperative complications between mobilized and non-mobilized patients revealed a significantly lower incidence of complications in the mobilized group (p<0.001). Analysis of intensive care unit (ICU) stay duration (p<0.001) and total hospital length of stay (p<0.001) also indicated that both ICU and overall hospital stays were significantly shorter in the mobilized group. Mortality rates were notably higher in the non-mobilized group (p=0.005). Furthermore, when analyzing only the mobilized group, patients who experienced postoperative complications had a significantly later mobilization time compared to those without complications (p=0.041). A strong, positive correlation was also found within the mobilized group between the timing of mobilization and total hospital stay duration. Conclusion: Early mobilization following chronic subdural hematoma surgery facilitate patients' reintegration into daily activities. Additionally, these measures minimize complications associated with immobilization and significantly reduce the length of hospitalization.

Sarcopenia

Sarcopenia is the progressive and involuntary loss of muscle mass and strength that occurs with elderly age. The definition of sarcopenia was first made by Rosenberg et al. in 1989. In 2010, the European Working Group on Sarcopenia in Older People (EWGSOP1) characterised the condition primarily by low muscle mass. The definition of sarcopenia that has been most widely adopted is that proposed by the EWGSOP1, which was updated in 2019 to become the EWGSOP2. Acute and chronic sarcopenia was included in the EWGSOP2 guideline for the first time. Although there is no consensus on the exact aetiology of sarcopenia, it is widely accepted that the condition is related to the natural ageing process. There are many chronic diseases associated with sarcopenia, including: cancer, chronic obstructive pulmonary disease (COPD), chronic heart failure, parkinson, cognitive impairment, depression, chronic kidney disease, diabetes mellitus (DM), human immunodeficiency virus (HIV), anorexia and osteoporosis. The assessment of sarcopenia includes a variety of methods and screening tools that are easily accessible and practical. The EWGSOP2 algorithm is delineated as "find–assess–confirm–severity," or F-A-C-S. A multidisciplinary approach is imperative for the early diagnosis and treatment of this condition. Given the multifactorial pathogenesis of sarcopenia, no definitive pharmacological therapy currently exists. Enhanced patient education and adherence to clinical recommendations are pivotal. The most effective strategies for combating sarcopenia involve a combination of nutritional support and resistance–aerobic exercise programs. Further research is needed to explore new pharmacological treatment approaches.

5-HT2C agonism as a neurotherapeutic for sarcopenia: preclinical proof of concept.

Sarcopenia, the pathological age-related loss of muscle mass and strength, contributes to physical decline, frailty, and diminished healthspan. The impact of sarcopenia is expected to rise as the aging population grows, and treatments remain limited. Therefore, novel approaches for enhancing physical function and strength in older adults are desperately needed. Recent evidence suggests that deficits in motor neuron excitability contribute significantly to age-related weakness. Accordingly, we hypothesized that enhancing motor neuron excitability could be a novel strategy for mitigating age-related declines in physical function and strength. To test this hypothesis, we targeted the 5-HT2C receptor with an agonist, as this receptor is known to enhance intrinsic excitability and amplify persistent inward currents of motor neurons. We found that a single oral gavage dose of 1.5, 3, and 6mg/kg lorcaserin, a selective 5-HT2C agonist, significantly increased indices of motor neuron excitability (e.g., cervical motor evoked potential (cMEP) amplitude by 53-64% and reduced attenuation in cMEP amplitude during repetitive stimulation), along with improvements in motor coordination (22-24% enhancement in rotarod performance) and functional strength (~ 17% increase in max weighted cart pull and 12% increase in grip strength) in aged mice. In contrast, antagonism of 5-HT2 receptors resulted in the opposite effect, reducing cMEP amplitude by ~ 26%, increasing attenuation of cMEP amplitude during repetitive stimulation, and decreasing grip strength by ~ 10% in aged mice. Overall, our findings indicate that enhancing motor neuron excitability via 5-HT2C agonism holds promise as a neurotherapeutic approach to treat age-related motor decline and sarcopenia.

Prevalence and incidence of sarcopenia in Swiss postmenopausal women: findings from the OsteoLaus Cohort

STUDY AIMS: Sarcopenia is a progressive, age-related loss of muscle mass, strength and function. Given the ageing population and the adverse outcomes associated with sarcopenia, monitoring its epidemiology is particularly important. This study aimed to describe sarcopenia prevalence, 5-year incidence and agreement between definitions using the latest operational criteria in Swiss postmenopausal women. METHODS: Postmenopausal women from the last 5 years of the CoLaus/OsteoLaus prospective population-based cohort were included based on complete case analysis (April 2015 to October 2022; Lausanne, Switzerland). We assessed appendicular lean mass via Dual X-ray Absorptiometry (GE Lunar iDXA), handgrip strength using a Jamar Dynamometer and 6-metre gait speed at multiple visits. Sarcopenia was defined based on handgrip strength and/or appendicular lean mass and/or gait speed using 11 definitions, including that from the European Working Group on Sarcopenia in Older People (EWGSOPII, 2019). Prevalence was measured as the number and rate of sarcopenic cases at the last visit, while incidence was measured as the number and rate of new sarcopenic cases over 2.5 or 5 years. RESULTS: A total of 930 women were included, with a mean (standard deviation) age of 72.9 (6.9) years, BMI of 25.7 (4.8) kg/m2, appendicular lean mass 16.8 (2.5) kg, handgrip strength 21.2 (5.5) kg, gait speed 1.1 (0.2) m/s. Sarcopenia prevalence based on EWGSOPII definitions ranged from 2.2% to 5.7%, while other definitions varied from 0.5% to 13.4%. The 5-year incidence rates based on EWGSOPII were 1.9% to 4.7%. Prevalence and incidence increased significantly between the lowest and highest age tertiles (Fisher’s exact test, p <0.05) for most definitions. Agreement between definitions was predominantly “none” or “minimal” according to the Cohen Kappa score. CONCLUSION: This population-based cohort of postmenopausal women highlights an increase in sarcopenia prevalence and incidence beginning in the seventh decade of life, underscoring the accelerated decline in muscle health with age. The minimal agreement between the definitions highlights the need for a consensus, which would improve future research and clinical implementations.

The Effect of Steel Reinforcement Diameter on the Behavior of Concrete Beams with Corrosion

Corrosion is one of the main problems affecting reinforced concrete (RC) structures, yet there remains a lack of studies in which the electrochemical and structural behavior of corroded RC elements are studied together. In this work, four RC beams with and without corrosion were studied to evaluate their electrochemical and structural behavior via the variable of the diameter of the longitudinal tension steel reinforcement (LTR). The beams were initially tested to determine their initial structural behavior and then subjected to sustained loads and wetting and drying cycles by applying a NaCl solution. The beams were tested a second time to determine their final structural behavior. The variations in the corrosion potential and corrosion rate of the LTR with time, together with concrete resistivity, cracking patterns, and load–displacement curves of the RC beam, are presented. It was found that the electrochemical parameters of the beams with corrosion were similar regardless of the steel reinforcement diameter; these parameters indicated a high level of corrosion. The maximum flexural strength loss was observed for beams with an LTR of 10 mm compared to those with a 13 mm diameter. The maximum cross-sectional area loss associated with pitting corrosion was greater for the beam with an LTR of 10 mm.

Experimental Study on Properties of Portland Cement Concrete Containing Recycled Asphalt Pavements

Although recycled asphalt pavement (RAP) are widely used in the construction of new, and reconstruction of old, hot mix asphalt (HMA) pavements, little research has been done to examine the potential of incorporating RAP into Portland cement concrete to replace virgin aggregate. Because RAP consists of aggregates coated by asphalt cement, the toughness of concrete made with RAP could be improved. In this paper, the mechanical properties of portland cement concrete containing RAP were investigated through laboratory experiments. Two types of RAP (coarse and fine RAP) materials were used to replace the equal amount of virgin coarse and/or fine aggregate. Silica fume and high-range water reducing agent (HRWRA) were also added into concrete mixtures to minimize the strength loss due to the incorporation of RAP. A total of 17 concrete batches were cast and tested for compressive and split tensile strengths, static compressive modulus of elasticity, and toughness index in accordance with ASTM standards. Test results indicated that there was a systematic reduction in the strengths and elastic modulus as well as an increase in the toughness index with the increase in RAP content. While the addition of HRWRA into the matrix improved the mechanical properties of concretes containing RAP, addition of silica fume unexpectedly did not.

Exerkines and Sarcopenia: Unveiling the Mechanism Behind Exercise-Induced Mitochondrial Homeostasis.

Background/Objectives: Sarcopenia, characterized by the progressive loss of muscle mass and strength, is linked to physical disability, metabolic dysfunction, and an increased risk of mortality. Exercise therapy is currently acknowledged as a viable approach for addressing sarcopenia. Nevertheless, the molecular mechanisms behind exercise training or physical activity remain poorly understood. The disruption of mitochondrial homeostasis is implicated in the pathogenesis of sarcopenia. Exercise training effectively delays the onset of sarcopenia by significantly maintaining mitochondrial homeostasis, including promoting mitophagy, improving mitochondrial biogenesis, balancing mitochondrial dynamics, and maintaining mitochondrial redox. Exerkines (e.g., adipokines, myokines, hepatokines, and osteokines), signaling molecules released in response to exercise training, may potentially contribute to skeletal muscle metabolism through ameliorating mitochondrial homeostasis, reducing inflammation, and regulating protein synthesis as a defense against sarcopenia. Methods: In this review, we provide a detailed summary of exercise-induced exerkines and confer their benefit, with particular focus on their impact on mitochondrial homeostasis in the context of sarcopenia. Results: Exercise induces substantial adaptations in skeletal muscle, including increased muscle mass, improved muscle regeneration and hypertrophy, elevated hormone release, and enhanced mitochondrial function. An expanding body of research highlights that exerkines have the potential to regulate processes such as mitophagy, mitochondrial biogenesis, dynamics, autophagy, and redox balance. These mechanisms contribute to the maintenance of mitochondrial homeostasis, thereby supporting skeletal muscle metabolism and mitochondrial health. Conclusions: Through a comprehensive investigation of the molecular mechanisms within mitochondria, the context reveals new insights into the potential of exerkines as key exercise-protective sensors for combating sarcopenia.

Associations Between Adherence to the Mediterranean Diet and Incident Sarcopenia in Prospective Cohort Studies.

The loss of skeletal muscle mass and strength, known as sarcopenia, is prevalent in older adults and linked to an increased risk of disability, frailty, and early mortality. Muscle health is crucial for the functionality and independence of older adults. As the aging population continuously grows, finding cost-effective strategies for preventing and treating sarcopenia is an important public health priority. While nutrition is recognized as a key factor in the development of sarcopenia, its role in preventing and treating the condition is still under investigation. In recent decades, nutritional research has shifted from a focus on individual nutrients or healthy foods to examining the combination of nutrients and foods in dietary patterns, along with their potential synergistic and antagonistic effects. A balanced diet and regular participation in physical activity are essential for maintaining musculoskeletal health. One of the healthy eating patterns with the greatest evidence of multiple health benefits is the Mediterranean diet, which has also been linked to positive effects on muscle function in observational studies. However, there is a lack of intervention studies. This review explores the updated evidence from longitudinal prospective studies on associations between adherence to the Mediterranean diet and sarcopenia in order to promote preventive and intervention strategies for healthy muscle aging.

Moderate anxiety may improve functional balance in older women with low muscle strength: a preliminary observation.

Anxiety commonly affects older individuals with negative consequences on various physical and motor performances such as balance. When coupled with age-related muscular strength loss, the effects on the ability to perform daily tasks could be particularly detrimental, particularly in older women who are more susceptible to anxiety, muscular strength losses and falls. The study aimed to verify the effects of anxiety on balance performance in relation to muscular strength level in healthy older women. Twenty-six individuals aged over 64 years underwent tests for anxiety, static and dynamic balance, and hand-grip strength. Two-way ANOVA was performed with anxiety (anxious vs. non-anxious) and strength (high vs. low) as independent variables. A significant main effect of anxiety and a significant interaction anxiety*strength for static balance were observed. The analysis of the interaction revealed a significant effect of anxiety on the non-preferred one-foot balance with differences between low and high strength subjects; for low levels of strength, anxious woman performed significantly better than non-anxious, for high levels of strength, anxiety had no effect. Moderate levels of anxiety may support balance performance in low strength condition. These findings if further verified on larger samples could add important information on the role of anxiety on motor performance in aging.

Effect of Plant Versus Animal Protein on Muscle Mass, Strength, Physical Performance, and Sarcopenia: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Dietary protein is recommended for sarcopenia-a debilitating condition of age-related loss of muscle mass and strength that affects 27% of older adults. The effects of protein on muscle health may depend on protein quality. The aim was to synthesize randomized controlled trial (RCT) data comparing plant with animal protein for muscle health. Forty-three eligible RCTs were sourced from Medline, Embase, Scopus, Web of Science, and CENTRAL databases. Four reviewers (R.J.R.-M., S.F.B., N.A.W., D.L.) extracted data from RCTs (study setting, population, intervention characteristics, outcomes, summary statistics) and conducted quality assessment using the Cochrane Risk of Bias 2.0. Standardized mean differences (SMDs) (95% CIs) were combined using a random-effects meta-analysis and forest plots were generated. I2 statistics were calculated to test for statistical heterogeneity. Thirty RCTs (70%) were eligible for meta-analysis and all examined muscle mass outcomes. Compared with animal protein, plant protein resulted in lower muscle mass following the intervention (SMD = -0.20; 95% CI: -0.37, -0.03; P = .02), with stronger effects in younger (<60 years; SMD = -0.20; 95% CI: -0.37, -0.03; P = .02) than in older (≥60 years; SMD = -0.05; 95% CI: -0.32, 0.23; P = .74) adults. There was no pooled effect difference between soy and milk protein for muscle mass (SMD = -0.02; 95% CI: -0.20, 0.16; P = .80) (n = 17 RCTs), yet animal protein improved muscle mass compared with non-soy plant proteins (rice, chia, oat, and potato; SMD = -0.58; 95% CI: -1.06, -0.09; P = .02) (n = 5 RCTs) and plant-based diets (SMD = -0.51; 95% CI: -0.91, -0.11; P = .01) (n = 7 RCTs). No significant difference was found between plant or animal protein for muscle strength (n = 14 RCTs) or physical performance (n = 5 RCTs). No trials examined sarcopenia as an outcome. Animal protein may have a small beneficial effect over non-soy plant protein for muscle mass; however, research into a wider range of plant proteins and diets is needed. PROSPERO registration no. CRD42020188658.

Optimising the mechanism of electroshock treatment on the tensile behaviour of the laser melting deposited Ti55531 alloy

ABSTRACT As an important additive manufacturing method, laser melting deposition (LMD) can be utilised to manufacture many high-property components. In this work, the Ti55531 alloy (Ti-5Al-5V-5Mo-3Cr-1Zr) is manufactured by LMD, and a novel electroshock treatment (EST) is introduced to modify the tensile properties of LMD Ti55531. The microstructure of LMD Ti55531 is an alternating arrangement of columnar and equiaxed β grains. The α phase has not undergone an obvious phase transition after 0.06 s EST, and many fine α phase precipitates with EST time increased to 0.08 s. The reduction of dislocations in the trigeminal grain boundary areas improves the ability to accommodate dislocations and plastic deformation, which improves the elongation of LMD Ti55531 from 14.5% to 17.6% without the loss of tensile strength after 0.06 s EST. The precipitation of the fine α phase in the β phase weakens the ability of the sample to withstand plastic deformation after 0.08 s EST, which reduces the elongation. All results indicate that EST is an effective and novel way to optimising the tensile properties of LMD titanium alloys.

Parametric study on configuration geometry effect on thrust performance of annular ED nozzles

A numerical investigation is conducted to uncover the parametric influence of configuration geometry on the thrust performance of annular expansion deflection (ED) nozzles. Based on the classic design principle of Taylor’s ED nozzle configuration, the influences of six geometric elements, covering the expansion channel region, the near-pintle region, and the shroud region, including 13 nozzle configurations, are examined in detail. The flow characteristics in each nozzle are demonstrated, according to which the connections between the geometric changes and nozzle thrust performance are elucidated. The present results show that the nozzle flow pattern is closely related to the nozzle configuration geometry. In the open operation mode of the ED nozzle, the wide expansion channel has very little restriction on the axial expansion of the exhaust gas. The high axial velocity brings strong shock strength and total pressure loss, which are unfavorable to the nozzle thrust performance. The large curvature of the shroud expansion section contributes greatly to the exhaust gas deflection, which increases the mass flow rate of the supersonic core flow zone through the nozzle exit plane, and therefore favors the thrust performance. In the closed operation mode, geometric differences in the expansion channel region have little effect on the supersonic gas, which fills almost the entire nozzle. The shroud region still affects the axial deflection of the gas and its large curvature is associated with superior thrust performance. These investigations suggest that the annular ED nozzles with narrow expansion channels and large shroud curvatures are superior in thrust performance.

Assessing Durability and Stability of Calcium Sulfoaluminate Cement-Stabilized Soils Under Cyclic Wet–Dry Conditions

Periodic wet–dry processes are a significant weathering mechanism that can quickly alter a soil’s mechanical characteristics, reducing its resilience and durability. This study investigates the physical and microstructural characterization of stabilized soils through experimental analysis. While the conventional approach to ground improvement involves the application of ordinary Portland cement (OPC) and lime for treating unstable soil, this research explores calcium sulfoaluminate (CSA) cement as an eco-friendly alternative with comparable efficacy and fewer adverse environmental effects. The primary objective is to evaluate the impact of cyclic wet–dry (W–D) events on the durability and stability of CSA cement-treated sand using comprehensive laboratory testing. Various samples were prepared with cement contents of 3%, 5%, 7%, and 10%, corresponding to the optimum moisture content. Stabilized soil specimens underwent testing for unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) after curing for 3, 7, 14, and 28 days. Subsequently, these specimens were exposed to zero, one, three, five, and seven W–D cycles. The outcomes show a decrease in the strength and durability index of the soil with a rising number of W–D cycles. However, the decline in the strength and durability of CSA-treated soil samples is significantly mitigated as the CSA content increases from 3% to 10%. The findings indicate that after seven W–D cycles, the UCS value of 10% cemented samples dropped by 14% after 28 days of curing, whereas 3% specimens experienced a 28% loss in strength. Similarly, UCS values for 5% and 7% cement content reduced from 666 kPa to 509 kPa and from 1587 kPa to 1331 kPa, respectively, indicating improved resilience with higher CSA content. The durability index was less affected during the first three cycles, but showed a more pronounced decline after five and seven cycles. For 3% cemented soil, the durability index dropped from 0.95 to 0.71, whereas for 10% cemented soil, it decreased from 0.97 to 0.82 after seven W–D cycles. The scanning electron microscope (SEM) also determines the cement–soil interaction before and after W–D, and it was noted that the pores and cracks increased after each cycle. Based on the findings, it is established that subgrade materials treated with CSA cement demonstrate durability, environmental sustainability, and suitability for integration into road construction projects.

Unravelling the transcriptomic symphony of muscle ageing: key pathways and hub genes altered by ageing and caloric restriction in rat muscle revealed by RNA sequencing

Age-related muscle wasting, sarcopenia is an extensive loss of muscle mass and strength with age and a major cause of disability and accidents in the elderly. Mechanisms purported to be involved in muscle ageing and sarcopenia are numerous but poorly understood, necessitating deeper study. Hence, we employed high-throughput RNA sequencing to survey the global changes in protein-coding gene expression occurring in skeletal muscle with age. Caloric restriction (CR) is a known prophylactic intervention against sarcopenia. Therefore, total RNA was isolated from the muscle tissue of both rats fed ad libitum and CR rats. RNA-seq data were subjected to Gene Ontology, pathway, co-expression, and interaction network analyses. This revealed the functional pathways most activated by both ageing and CR, as well as the key “hub” proteins involved in their activation.RNA-seq revealed 442 protein-coding genes to be upregulated and 377 to be downregulated in aged muscle, compared to young muscle. Upregulated genes were commonly involved in protein folding and immune responses; meanwhile, downregulated genes were often related to developmental biology. CR was found to suppress 69.7% and rescue 57.8% of the genes found to be upregulated and downregulated in aged muscle, respectively. In addition, CR uniquely upregulated 291 and downregulated 304 protein-coding genes. Hub genes implicated in both ageing and CR included Gc, Plg, Irf7, Ifit3, Usp18, Rsad2, Blm and RT1-A2, whilst those exclusively implicated in CR responses included Alb, Apoa1, Ambp, F2, Apoh, Orm1, Mx1, Oasl2 and Rtp4. Hub genes involved in ageing but unaffected by CR included Fgg, Fga, Fgb and Serpinc1. In conclusion, this comprehensive RNA sequencing study highlights gene expression patterns, hub genes and signalling pathways most affected by ageing in skeletal muscle. This data may provide the initial evidence for several targets for potential future therapeutic interventions against sarcopenia.

Muscle Strength Loss in Women with COVID-19 and the Restorative Role of Physiotherapy.

Objective: This study aimed to evaluate the effects of an 8-week physiotherapy program on muscle strength, functional capacity, respiratory function, and quality of life in women recovering from COVID-19. Methods: A prospective cohort study was conducted with 42 women aged 18-65 who experienced muscle strength loss and functional impairments post-COVID-19. Participants underwent personalized physiotherapy interventions, including resistance training, respiratory therapy, and functional mobility exercises, for 8 weeks. Data were collected at baseline and post-intervention, including handgrip strength, 6-Minute Walk Test (6MWT), forced vital capacity (FVC), Fatigue Severity Scale (FSS), and SF-36 scores. Statistical analyses were performed using paired t-tests and Wilcoxon signed-rank tests. Results: Significant improvements were observed in muscle strength, with right-handgrip strength increasing from 18.5 ± 4.2 kg to 22.8 ± 4.6 kg (p < 0.001) and left-handgrip strength from 17.2 ± 4.1 kg to 21.1 ± 4.5 kg (p < 0.001). Functional capacity improved, as evidenced by a 6MWT distance increase from 382 ± 62 m to 438 ± 57 m (p < 0.001). Respiratory function parameters, including FVC and FEV1, also showed significant gains (p < 0.01). Quality of life scores improved significantly, particularly in physical functioning and vitality domains, while fatigue levels decreased markedly (p < 0.001). Conclusions: The results demonstrate the effectiveness of physiotherapy in addressing the physical and functional consequences of COVID-19 in women. These findings emphasize the importance of incorporating physiotherapy into post-COVID-19 rehabilitation protocols to enhance recovery and quality of life.

Previous short-term disuse dictates muscle gene expression and physiological adaptations to subsequent resistance exercise.

Short-term unloading experienced following injury or hospitalisation induces muscle atrophy and weakness. The effects of exercise following unloading have been scarcely investigated. We investigated the functional and molecular adaptations to a resistance training (RT) programme following short-term unloading. Eleven males (22.09±2.91years) underwent 10days of unilateral lower limb suspension (ULLS) followed by 21days of knee extensor RT (three times/week). Data collection occurred at Baseline (LS0), after ULLS (LS10) and at active recovery (AR21). Knee extensor maximum voluntary contraction (MVC) was evaluated. Quadriceps volume was estimated by ultrasonography. Muscle fibre cross-sectional area, fibre type distribution, glycogen content and succinate dehydrogenase (SDH) activity were measured from vastus lateralis biopsies. Mitochondrial-related proteins were quantified by western blot and transcriptional responses were assessed by RNA sequencing. Following ULLS, quadriceps volume and MVC decreased significantly (3.7%, P<0.05; 29.3%, P<0.001). At AR21 (vs. LS10), MVC was fully restored (42%) and quadriceps volume increased markedly (18.6%, P<0.001). Glycogen content and whole-body water increased at AR21 (14%, P<0.001; 3.1%, P<0.05). We observed a marked increase in fibre type I at AR21 (38%, P<0.05). SDH immunoreactivity increased significantly after exercise (20%, P<0.001). Mitochondrial fusion (MFN1, MFN2 and OPA1) and fission (DRP1) proteins were markedly increased by RT, and the most differentially expressed genes belonged to oxidative phosphorylation pathways. In contrast with what is usually observed after RT, oxidative metabolism, slow fibre type and mitochondrial dynamics were enhanced beyond expected. We propose that prior exposure to short-term muscle unloading may drive the nature of molecular adaptations to subsequent RT. KEY POINTS: Short-term unloading is often experienced during recovery from injuries and hospitalisation, leading to loss of muscle mass and strength. Although exercise can be beneficial in mitigating/reversing such alterations during disuse, only a few studies have focused on the effects of exercise following muscle unloading. With an integrative physiological approach, we aimed to elucidate the basic mechanisms of muscle function recovery in response to 21days of resistance exercise that followed 10days of unilateral lower limb suspension (ULLS), assessing whether the mechanisms underlying recovery are defined by a specific reversal of those that occurred during disuse. Resistance training was successful in recovering functional and structural muscle properties after 10days of ULLS, but in contrast with what is usually observed in response to this training modality, oxidative metabolism and slow fibre type were mostly enhanced. We propose that prior exposure to short-term muscle unloading may drive the adaptations to subsequent exercise.

Comparison of Maximum Isometric Strength of the Hip Joint Abductor and Knee Joint Extensor Muscles between Knee Osteoarthritis Patients with and without Self-reported Instability.

Patients with knee osteoarthritis (KOA) often have impaired muscle function of the weight-bearing muscles, particularly in the knee and hip joints. This can lead to a significant loss of strength and power and may play a role in the perceived instability of the knee joint. The purpose of this study was to compare the maximum isometric strength of the hip abductor and knee extensor muscles between patients with KOA with and without perceived instability.Nineteen patients with KOA participated in this cross-sectional study and were divided into two groups. The first group (n=10; women =4, men =6, mean age =67.4 ± standard deviation [SD] 6.4 years) consisted of patients with self-reported instability in the knee joint, and the second group (n=9; women =5, men =4, mean age =69.6 ± SD 6.7 years) consisted of patients without self-reported instability. Functional and activity limitations were quantified using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Maximum isometric strength of the hip abductors and knee extensors was measured using a belt-mounted handheld dynamometer and expressed as torque (Newton meters [Nm]) by multiplication with the determined lever arm. Torque was normalized to body weight and height.Patients with instability (median WOMAC score =68) achieved a significantly lower mean torque in hip abduction than the patients without instability (median WOMAC score =39) (p=0.01; Cohen's d=1.31). There was no significant difference in knee extension torque between the groups (p=0.202; Cohen's d=0.58).KOA patients with instability were able to develop significantly lower hip abductor strength than those without instability, suggesting that targeted strength training of this muscle group may be important for this group of patients.

Enhanced Dielectric Performance in PVDF-Based Composites by Introducing a Transition Interface.

Polymeric dielectrics have garnered significant interest worldwide due to their excellent comprehensive performance. However, developing polymeric dielectric films with high permittivity (εr) and breakdown strength (Eb) and low dielectric loss (tanδ) presents a huge challenge. In this study, amorphous aluminum oxide (Al2O3, AO) transition interfaces with nanoscale thickness were constructed between titanium oxide (TiO2, TO) nanosheets and polyvinylidene fluoride (PVDF) to manufacture composites (PVDF/TO@AO). TO@AO nanosheets showed favorable dispersion in the polymer-based composites. Improved permittivity, suppressed dielectric loss, and enhanced breakdown strength were achieved by introducing AO coating with intermediate permittivity onto TO nanosheets to build a transition interface. The transition interface efficiently depressed the mobility of the charge carrier and electric conduction of the PVDF/TO@AO composites. As a result, the PVDF-based composite with 1 wt% TO@AO showed superior comprehensive performance, including high εr of ~12.7, low tanδ of ~0.017, and exceptional Eb of ~357 kV/mm. This strategy supplies a novel paradigm for the application of fabricating dielectric films with excellent comprehensive performance.

Sarcopenia is a risk factor for postoperative delirium in geriatric hip fracture patients: a retrospective study.

Various factors contribute to postoperative delirium (POD) in elderly patients undergoing hip fracture surgeries. Sarcopenia was defined as the progressive loss of skeletal muscle mass and strength associated with aging. The aim of this study was to explore the prevalence of POD and sarcopenia in geriatric patients undergoing hip fracture surgeries and to investigate the correlation between preoperative sarcopenia and POD. After applying specific inclusion and exclusion criteria, the information of 234 patients were retrospectively collected. POD was screened for with 4A's Test and diagnosed with DSM-5 criteria. The incidences of POD and sarcopenia were calculated. The demographic and perioperative features as well as comorbidities of delirious and non-delirious patients were analyzed and the risk factors analysis for POD in elderly hip fracture patients were conducted through univariate analysis and multivariate regression analysis. 48.7% patients were diagnosed of POD, 78.95% of which were females. The average age of delirious and non-delirious patients were 84.75 years and 80.63 years, respectively. The incidence of sarcopenia was 41.02% for all the included patients with 60.53% for delirious patients and 20.55% for non-delirious patients. Results of univariate analysis showed that sarcopenia (OR:5.281, 95%CI 2.988-9.337, p = 0.000), age increase per year (OR:1.128, 95CI 1.070-1.190, p = 0.000), operation duration increase (OR:1.017, 95%CI 1.004-1.030, p = 0.011), intertrochanteric fracture (OR:2.571, 95%CI 1.517-4.358, p = 0.000), dementia (OR: 6.029, 95%CI 2.532-14.359, p = 0.000), ASA > 2 (OR: 6.955, 95%CI 3.461-13.976, p = 0.000), coronary heart disease (OR: 2.201, 95%CI 1.257-3.854, p = 0.006), renal insufficiency (OR: 2.215, 95%CI 1.187-4.133, p = 0.012) and COPD (OR: 2.554, 95%CI 1.414-4.615, p = 0.002) were risk factors for POD. Results of multivariate analysis identified sarcopenia (OR: 2.457, 95% CI 1.226-4.923, p = 0.011), ASA > 2 (OR: 3.968, 95% CI 1.805-8.722, p = 0.001), dementia (OR: 3.912, 95% CI 1.390-11.014, p = 0.010) and coronary heart disease (OR: 2.176, 95% CI 1.044-4.538, p = 0.038) as independent risk factors for POD in geriatric hip fracture patients. The incidences of POD and sarcopenia in geriatric hip fracture patients are high. Sarcopenia is an independent risk factor for POD in geriatric hip fracture patients.

A randomized controlled trial to assess the efficacy of standardized tai chi in prefrail older adults with immunosenescence: design and protocol

BackgroundFrailty is a common geriatric syndrome worldwide, and its early identification and intervention have important clinical significance. Resistance training has been recommended as an efficient means to combat loss of muscle strength and mass; however, it is often not a prioritized option for older adults. Tai chi is a well-known traditional Chinese exercise that has a beneficial impact on physical performance, balance ability, metabolism, and immune function.AimsWith the newly emerged concept of muscle-immune homeostasis, this study focused on determining the efficacy of tai chi prefrail older adults who develop immunosenescence. Furthermore, the proper timing of the exercise regimen for maximizing the therapeutic effect of tai chi has also been explored.MethodsThis 12-week, multicenter, randomized controlled trial (RCT) was conducted with participants between 60 and 75 years of age. A total of 144 prefrail participants were included in this study and were randomized (1:1:1:1) to four groups: (1) a control group with only health education, (2) a morning tai chi group, (3) a morning resistance training group, and (4) an afternoon tai chi group. The primary endpoints included physical performance, frailty index scores, muscle strength, and mass, and the secondary endpoints were the sarcopenia quality of life score, Berg balance scale score, bioenergetic anti-stress index (BASI), and immune risk profile (IRP). The data were analyzed according to the intention-to-treat protocol.DiscussionThe results of this investigation aided in determining whether tai chi effectively reversed the prefrail state of older adults and ameliorated biomarkers of immunosenescence. Furthermore, proper exercise timing was also determined to maximize the efficacy of physical training.Trial registrationChinese Clinical Trial Registry; registration number: ChiCTR2200065815; prospectively registered on November 16th, 2022.