Ultra-bright, efficient and stable perovskite light-emitting diodes.

Metal halide perovskites are attracting a lot of attention as next-generation light-emitting materials owing to their excellent emission properties, with narrow band emission1-4. However, perovskite light-emitting diodes (PeLEDs), irrespective of their material type (polycrystals or nanocrystals), have not realized high luminance, high efficiency and long lifetime simultaneously, as they are influenced by intrinsic limitations related to the trade-off of properties between charge transport and confinement in each type of perovskite material5-8. Here, we report an ultra-bright, efficient and stable PeLED made of core/shell perovskite nanocrystals with a size of approximately 10 nm, obtained using a simple in situ reaction of benzylphosphonic acid (BPA) additive with three-dimensional (3D) polycrystalline perovskite films, without separate synthesis processes. During the reaction, large 3D crystals are split into nanocrystals and the BPA surrounds the nanocrystals, achieving strong carrier confinement. The BPA shell passivates the undercoordinated lead atoms by forming covalent bonds, and thereby greatly reduces the trap density while maintaining good charge-transport properties for the 3D perovskites. We demonstrate simultaneously efficient, bright and stable PeLEDs that have a maximum brightness of approximately 470,000 cd m-2, maximum external quantum efficiency of 28.9% (average = 25.2 ± 1.6% over 40 devices), maximum current efficiency of 151 cd A-1 and half-lifetime of 520 h at 1,000 cd m-2 (estimated half-lifetime >30,000 h at 100 cd m-2). Our work sheds light on the possibility that PeLEDs can be commercialized in the future display industry.

Programmable Threshold Logic Implementations in a Memristor Crossbar Array.

In this study, we demonstrate the implementation of programmable threshold logics using a 32 × 32 memristor crossbar array. Thanks to forming-free characteristics obtained by the annealing process, its accurate programming characteristics are presented by a 256-level grayscale image. By simultaneous subtraction between weighted sum and threshold values with a differential pair in an opposite way, 3-input and 4-input Boolean logics are implemented in the crossbar without additional reference bias. Also, we verify a full-adder circuit and analyze its fidelity, depending on the device programming accuracy. Lastly, we successfully implement a 4-bit ripple carry adder in the crossbar and achieve reliable operations by read-based logic operations. Compared to stateful logic driven by device switching, a 4-bit ripple carry adder on a memristor crossbar array can perform more reliably in fewer steps thanks to its read-based parallel logic operation.

Dual-polarization MZM-based photonic nonlinear analog self-interference cancellation for in-band full-duplex radios.

In this paper, we propose a dual-polarization Mach-Zehnder modulator-based photonic nonlinear analog self-interference cancellation (SIC) technique for in-band full duplex (IBFD) systems. By using the proposed technique, an arbitrary 4th order nonlinear transfer function can be generated, meaning the performance limitation caused by the nonlinearity of the analog SIC circuit can be overcome by imitating the nonlinear transfer function of the analog SIC circuit before cancellation. This paper also presents a performance analysis through simulations and the results of a proof-of-concept demonstration. In the experiment, the proposed nonlinear SIC technique could achieve 29 dB cancellation over 500 MHz bandwidth centered at 1.25 GHz frequency along various degree of distortion caused by nonlinearity. In addition, the performance enhancements achieved by the proposed technique are evaluated in terms of error vector magnitudes (EVMs) and constellations of the signal-of-interest (SOI) in the simulation which is based on the experimental SIC results. More than 3 dB of SOI power gain could be obtained in evaluated EVM performances.

Sympathetic dysfunction as an early indicator of autonomic involvement in Parkinson's disease.

PURPOSE: The specific characteristics of autonomic involvement in patients with early Parkinson's disease (PD) are unclear. This study aimed to evaluate the characteristics of autonomic dysfunction in drug-naïve patients with early-stage PD without orthostatic hypotension (OH) by analyzing Valsalva maneuver (VM) parameters. METHODS: We retrospectively analyzed drug-naïve patients without orthostatic hypotension (n = 61) and controls (n = 20). The patients were subcategorized into early PD (n = 35) and mid-PD (n = 26) groups on the basis of the Hoehn and Yahr staging. VM parameters, including changes in systolic blood pressure at late phase 2 (∆SBPVM2), ∆HRVM3, Valsalva ratio (VR), pressure recovery time, adrenergic baroreflex sensitivity, and vagal baroreflex sensitivity, were assessed. RESULTS: In the early PD group, ∆SBPVM2, a marker of sympathetic function, was significantly lower compared with that in controls (risk ratio = 0.95, P = 0.027). Receiver operating characteristic (ROC) curve analysis showed an optimal cut-off value of -10 mmHg for ∆SBPVM2 [P = 0.002, area under the curve (AUC): 0.737]. VR exhibited an inverse relationship with Unified Parkinson's Disease Rating Scale Part 3 scores in the multivariable regression analysis (VR: P = 0.038, ß = -28.61), whereas age showed a positive relationship (age: P = 0.027, ß = 0.35). CONCLUSION: The ∆BPVM2 parameter of the VM may help detect autonomic nervous system involvement in early-PD without OH. Our results suggest that sympathetic dysfunction is an early manifestation of autonomic dysfunction in patients with PD.

Multifunctionality of Additively Manufactured Kelvin Foam for Electromagnetic Wave Absorption and Load Bearing.

Rationally engineered porous structures enable lightweight broadband electromagnetic (EM) wave absorbers for countering radar signals or mitigating EM interference between multiple components. However, the scalability of such structures has been hindered by their limited mechanical properties resulting from low density. Herein, an additively manufactured Kelvin foam-based EM wave absorber (KF-EMA) is reported that exhibits multifunctionality, namely EM wave absorption and light-weighted load-bearing structures with constant relative stiffness made possible using bending-dominated lattice structures. Based on tuning design parameters, such as the backbone structures and constituent materials, the proposed KF-EMA features a multilayered 3D-printed design with geometrically optimized KF structures made of carbon black-based backbone composites. The developed KF-EMA demonstrated an absorbance greater than 90% at frequencies ranging from 5.8 to 18 GHz (average EM wave absorption rates of 95.89% and maximum of 99.1% at 15.8 GHz), while the low-density structures of the absorber (≈200 kg m-3 ) still maintained a compression index between the stiffness and relative density (n = 2) under compression. The design strategy paves the way for using metamaterials as mechanically reinforced EM wave absorbers that enable multifunctionality by optimizing unit-cell parameters through a single and low-density structure.

The Involvement of the Hypothalamus-Pituitary-Adrenal Axis in the Development of Hyperalgesia during the Early Postoperative Period.

INTRODUCTION: Hyperalgesia frequently occurs after surgery and is associated with adverse effects on surgical outcomes. Thus, we aimed to examine whether the hypothalamus-pituitary-adrenal (HPA) axis function after surgery is involved in the development of postoperative hyperalgesia. METHODS: Surgery- and pain-related variables were measured 24 and 48 h after the first and second total knee arthroplasties (TKAs) in postmenopausal patients undergoing 1-week-interval staged bilateral TKA. Two sets of saliva samples were consecutively collected from patients before (pre-T1) and 1 week after (post-T1) the first TKA (n = 69). HPA axis function was analyzed in a subgroup of 20 patients with a typical cortisol awakening response (CAR) in both the sets of saliva samples. RESULTS: Surgery-related variables were comparable between the first and second TKAs. However, pain-related variables (pain ratings and the amount of opioid analgesics consumed) were greater after the second than the first TKA. Cortisol and dehydroepiandrosterone (DHEA) secretion during the post-awakening period (CARauc and Daucawk, respectively) was higher at post-T1 than at pre-T1, but the molar CARauc/Daucawk ratio was comparable between the time points examined. No relationship was observed between the pre-T1 CARauc and pain ratings after the first TKA. However, post-T1 CARauc showed a positive correlation with pain ratings after the second TKA. Postoperative pain ratings were negatively correlated with Daucawk and positively correlated with the molar CARauc/Daucawk ratio at all examined time points. DISCUSSION/CONCLUSION: The results suggest that adrenocortical steroidogenic activity favoring the production of cortisol over DHEA after surgery may contribute to the development of hyperalgesia during the early postoperative period.

Purification of phenoloxidase from Haliotis discus hannai and its anti-inflammatory activity in vitro.

Haliotis discus hannai, a food with a high protein content, is widely consumed in Asian countries. It is known to have antioxidant, anticancer, and antibacterial effects. Since the biological significance of H. discus hannai hemolymph has not been widely studied, the objective of the present study was to purify phenoloxidase (PO) and investigate its immunological effects on human colonic epithelial cells. PO was purified through ammonium sulfate precipitation and one step column chromatography. The molecular weight of the protein was about 270 kDa. When PO was mixed with Gram-negative bacteria-derived lipopolysaccharide (LPS) at various ratios (10:1-1:10, w/w), the amount of residual LPS was reduced. PO at concentrations up to 200 µg/mL was not cytotoxic to HT-29 cells. The inflammatory response induced by LPS in HT-29 cells was regulated when the concentration of PO was increased. With increasing concentration of PO, production levels of pro-inflammatory cytokines, cytokines associated with hyperimmune responses such as IL4, IL-5, and INF-γ, and prostaglandin 2 (PGE2) were regulated. It was thought that simultaneous treatment with PO and LPS anti-inflammatory effects in HT-29 cells showed by regulating the ERK1/2-mediated NF-κB pathway. Results of this study suggest that H. discus hannai hemolymph is involved in the regulation of Gram-negative bacteria-related inflammatory immune responses in human colonic epithelial cells.

Artistic Robotic Arm: Drawing Portraits on Physical Canvas under 80 Seconds.

In recent years, the field of robotic portrait drawing has garnered considerable interest, as evidenced by the growing number of researchers focusing on either the speed or quality of the output drawing. However, the pursuit of either speed or quality alone has resulted in a trade-off between the two objectives. Therefore, in this paper, we propose a new approach that combines both objectives by leveraging advanced machine learning techniques and a variable line width Chinese calligraphy pen. Our proposed system emulates the human drawing process, which entails planning the sketch and creating it on the canvas, thus providing a realistic and high-quality output. One of the main challenges in portrait drawing is preserving the facial features, such as the eyes, mouth, nose, and hair, which are crucial for capturing the essence of a person. To overcome this challenge, we employ CycleGAN, a powerful technique that retains important facial details while transferring the visualized sketch onto the canvas. Moreover, we introduce the Drawing Motion Generation and Robot Motion Control Modules to transfer the visualized sketch onto a physical canvas. These modules enable our system to create high-quality portraits within seconds, surpassing existing methods in terms of both time efficiency and detail quality. Our proposed system was evaluated through extensive real-life experiments and showcased at the RoboWorld 2022 exhibition. During the exhibition, our system drew portraits of more than 40 visitors, yielding a survey outcome with a satisfaction rate of 95%. This result indicates the effectiveness of our approach in creating high-quality portraits that are not only visually pleasing but also accurate.

Surface Electromyography-Driven Parameters for Representing Muscle Mass and Strength.

The need for developing a simple and effective assessment tool for muscle mass has been increasing in a rapidly aging society. This study aimed to evaluate the feasibility of the surface electromyography (sEMG) parameters for estimating muscle mass. Overall, 212 healthy volunteers participated in this study. Maximal voluntary contraction (MVC) strength and root mean square (RMS) values of motor unit potentials from surface electrodes on each muscle (biceps brachii, triceps brachii, biceps femoris, rectus femoris) during isometric exercises of elbow flexion (EF), elbow extension (EE), knee flexion (KF), knee extension (KE) were acquired. New variables (MeanRMS, MaxRMS, and RatioRMS) were calculated from RMS values according to each exercise. Bioimpedance analysis (BIA) was performed to determine the segmental lean mass (SLM), segmental fat mass (SFM), and appendicular skeletal muscle mass (ASM). Muscle thicknesses were measured using ultrasonography (US). sEMG parameters showed positive correlations with MVC strength, SLM, ASM, and muscle thickness measured by US, but showed negative correlations with SFM. An equation was developed for ASM: ASM = -26.04 + 20.345 × Height + 0.178 × weight - 2.065 × (1, if female; 0, if male) + 0.327 × RatioRMS(KF) + 0.965 × MeanRMS(EE) (SEE = 1.167, adjusted R2 = 0.934). sEMG parameters in controlled conditions may represent overall muscle strength and muscle mass in healthy individuals.

Prussian Blue Nanolayer-Embedded Separator for Selective Segregation of Nickel Dissolution in High Nickel Cathodes.

Transition metal layered oxides (LiNixCoyMn1-x-yO2, NCM) have been considered as one of the most promising cathodes for lithium-ion batteries used in long-mileage electric vehicles and energy storage systems. Despite its potential interest, dissolved transition metal (TM) ions toward anode sides can catalyze parasitic reactions such as electrolytic decomposition and dendritic Li growth, ultimately leading to catastrophic safety hazards. In this study, we demonstrate that Prussian Blue (PB) nanoparticles anchored to a commercial PE separator significantly reduce cell resistance and effectively suppress TM crossover during cycling, even under harsh conditions that accelerate Ni dissolution. Therefore, using a PB-coated separator in a harsh condition to intentionally dissolve Ni2+ ions at a high cutoff potential of 4.6 V, NCM||graphite full cells maintain 50.8% of their initial capacity at the 150th cycle. Scalable production of PB-coated separator through the facile synthetic methods can help establish a new research direction for the design of high-energy-density batteries.

Serial Comparison of Patient-Reported Outcomes of Immediate Breast Reconstruction: Direct-to-Implant Versus Deep Inferior Epigastric Perforator Flap.

BACKGROUND: Direct-to-implant (DTI) and deep inferior epigastric artery perforator (DIEP) flaps are the two most common methods of immediate breast reconstruction. This study aimed to compare patient-reported outcomes between the two methods and to evaluate whether outcomes change over time. METHODS: The data of patients who underwent immediate breast reconstruction using DTI or DIEP flaps between July 2017 and October 2021 were retrospectively reviewed. Patients who completed the BREAST-Q Reconstruction Module at 6 months and > 12 months after reconstruction were analyzed. Mann-Whitney and Wilcoxon signed-rank test were used to compare outcome between DTI and DIEP groups, and serial comparisons were performed. RESULTS: Of 375 patients included in the analysis, 146 patients completed questionnaires > 1 year of follow-up (20.79 ± 8.55 months). The DTI and DIEP groups had 102 (69.9%) and 44 (30.1%) patients, respectively. There were no intergroup differences in the mean scores representing any of the domains at 6 postoperative months. After > 1 year of follow-up, patients who underwent DIEP-flap reconstruction had greater satisfaction with their breast reconstructions (p < 0.001) and greater satisfaction with their overall outcomes (p < 0.001). In the DTI group, satisfaction scores did not change over time in any of the domains. In the DIEP group, however, the mean scores reflecting satisfaction with the breast (p = 0.001), overall outcome (p = 0.045), psychosocial well-being (p = 0.015), and sexual well-being (p = 0.042) significantly increased over long-term follow-up relative to the scores at 6 postoperative months. CONCLUSIONS: Patient-reported outcomes improved over time in association with DIEP reconstructions, reflecting higher satisfaction levels than those associated with DTI reconstruction. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Three-dimensional Volume Changes of the Reconstructed Breast Following DIEP Flap Breast Reconstruction.

BACKGROUND: This study aimed to assess whether the reconstructed breast volume changed postoperatively following a deep inferior epigastric artery perforator (DIEP) flap. METHODS: Patients were included if they had undergone unilateral breast reconstruction with a DIEP flap at the two selected centers between April 2017 and September 2019. Serial 3-D surface imaging of both breasts was taken at 1, 3, 6, and 12 months postoperatively. The primary outcome was a volume ratio of the reconstructed to the contralateral breast. A linear mixed-effect model was used to evaluate whether the DIEP flap volume changed according to the postoperative time. RESULTS: A total of 74 patients were included in the analysis. The mean volume ratio of the reconstructed side compared with the contralateral breast at 1, 3, 6, and 12 months postoperatively were 106.9%, 105.9%, 108.7%, and 107.6%, respectively. In the linear mixed effect model, the volume ratio of the reconstructed breast did not change over time for immediate reconstructions (p = 0.376). However, there was an increase over time in delayed reconstructions (p = 0.043). Adjuvant radiation, chemotherapy, and hormone therapy did not influence the volume ratio of the reconstruced breast. Correlation analysis using repeatedly measured values showed that both reconstruced and healthy breast volumes had positive correlation with the patient's body weight (p < 0.001). On the other hand, volume ratio of the breasts was not influenced by the patient's body weight (p = 0.493). The volume ratio of the reconstructed breast significantly decreased in the upper inner (p = 0.003) and the upper outer (p = 0.006) quadrants, while increasing in the lower outer (p = 0.002) quadrant throughout the first-year postoperative period. CONCLUSION: The volume ratio of the reconstructed to the contralateral breast does not decrease postoperatively following DIEP flap breast reconstruction.

Daily changes in spatial accessibility to ICU beds and their relationship with the case-fatality ratio of COVID-19 in the state of Texas, USA.

During the COVID-19 pandemic, many patients could not receive timely healthcare services due to limited availability and access to healthcare resources and services. Previous studies found that access to intensive care unit (ICU) beds saves lives, but they overlooked the temporal dynamics in the availability of healthcare resources and COVID-19 cases. To fill this gap, our study investigated daily changes in ICU bed accessibility with an enhanced two-step floating catchment area (E2SFCA) method in the state of Texas. Along with the increased temporal granularity of measurements, we uncovered two phenomena: 1) aggravated spatial inequality of access during the pandemic, and 2) the retrospective relationship between insufficient ICU bed accessibility and the high case-fatality ratio of COVID-19 in rural areas. Our findings suggest that those locations should be supplemented with additional healthcare resources to save lives in future pandemic scenarios.

Peptidomimetic Wet-Adhesive PEGtides with Synergistic and Multimodal Hydrogen Bonding.

The remarkable underwater adhesion of mussel foot proteins has long been an inspiration in the design of peptidomimetic materials. Although the synergistic wet adhesion of catechol and lysine has been recently highlighted, the critical role of the polymeric backbone has remained largely underexplored. Here, we present a peptidomimetic approach using poly(ethylene glycol) (PEG) as a platform to evaluate the synergistic compositional relation between the key amino acid residues (i.e., DOPA and lysine), as well as the role of the polyether backbone in interfacial adhesive interactions. A series of PEG-based peptides (PEGtides) were synthesized using functional epoxide monomers corresponding to catechol and lysine via anionic ring-opening polymerization. Using a surface force apparatus, highly synergistic surface interactions among these PEGtides with respect to the relative compositional ratio were revealed. Furthermore, the critical role of the catechol-amine synergy and diverse hydrogen bonding within the PEGtides in the superior adhesive interactions was verified by molecular dynamics simulations. Our study sheds light on the design of peptidomimetic polymers with reduced complexity within the framework of a polyether backbone.

Distinct limbic dopamine regulation across olfactory-tubercle subregions through integration of in vivo fast-scan cyclic voltammetry and optogenetics.

The olfactory tubercle (OT), an important component of the ventral striatum and limbic system, is involved in multi-sensory integration of reward-related information in the brain. However, its functional roles are often overshadowed by the neighboring nucleus accumbens. Increasing evidence has highlighted that dense dopamine (DA) innervation of the OT from the ventral tegmental area (VTA) is implicated in encoding reward, natural reinforcers, and motivated behaviors. Recent studies have further suggested that OT subregions may have distinct roles in these processes due to their heterogeneous DA transmission. Currently, very little is known about regulation (release and clearance) of extracellular DA across OT subregions due to its limited anatomical accessibility and proximity to other DA-rich brain regions, making it difficult to isolate VTA-DA signaling in the OT with conventional methods. Herein, we characterized heterogeneous VTA-DA regulation in the medial (m) and lateral (l) OT in "wild-type," urethane-anesthetized rats by integrating in vivo fast-scan cyclic voltammetry with cell-type specific optogenetics to stimulate VTA-DA neurons. Channelrhodopsin-2 was selectively expressed in the VTA-DA neurons of wild-type rats and optical stimulating parameters were optimized to determine VTA-DA transmission across the OT. Our anatomical, neurochemical, and pharmacological results show that VTA-DA regulation in the mOT is less dependent on DA transporters and has greater DA transmission than the lOT. These findings establish the OT as a unique, compartmentalized structure and will aid in future behavioral characterization of the roles of VTA-DA signaling in the OT subregions in reward, drug addiction, and encoding behavioral outputs necessary for survival.

Investigation and direct observation of sidewall leakage current of InGaN-Based green micro-light-emitting diodes.

Electrical and optical characteristics of InGaN-based green micro-light-emitting diodes (µLEDs) with different active areas are investigated; results are as follows. Reverse and forward leakage currents of µLED increase as emission area is reduced owing to the non-radiative recombination process at the sidewall defects; this is more prominent in smaller µLED because of larger surface-to-volume ratio. Leakage currents of µLEDs deteriorate the carrier injection to light-emitting quantum wells, thereby degrading their external quantum efficiency. Reverse leakage current originate primarily from sidewall edges of the smallest device. Therefore, aggressive suppression of sidewall defects of µLEDs is essential for low-power and downscaled µLEDs.

Advances in the Pathophysiology and Management of Supine Hypertension in Patients with Neurogenic Orthostatic Hypotension.

PURPOSE OF REVIEW: Patients with neurogenic orthostatic hypotension (OH) frequently have hypertension in the supine position (sHTN). We review the controversies surrounding the need and safety of treating sHTN in patients with OH. RECENT FINDINGS: The presence of sHTN complicates the management of OH because treatment of one can worsen the other. New approaches have been developed to treat OH without worsening sHTN by preferentially improving standing blood pressure, such as medications that harness the patient's residual sympathetic tone like pyridostigmine and atomoxetine, and devices such as an automated abdominal binder that targets the inappropriate splanchnic venous pooling causing OH. There is a reluctance to treat sHTN for fear of increasing the risks of falls and syncope associated with OH, thought to be more immediate and dangerous than the late complications of organ damage associated with sHTN. This, however, does not take into account that nighttime sHTN induces natriuresis, volume loss, and begets daytime orthostatic hypotension. It is possible to treat sHTN in ways that reduce the risk of worsening OH. Furthermore, novel approaches, such as the use of local heat can control nighttime sHTN, reduce nocturia, and improve OH. Although continued progress is needed, recent findings offer hope that we can treat nocturnal sHTN and at the same time improve daytime OH, lessening the controversy whether to treat or not sHTN.

Electron-beam induced damage process for Ca2Na2Nb5O16nanosheets.

Dielectric two-dimensional oxide nanosheets are attractive because of their thermal stability and high-k property. However, their atomic structure characterization has been limited since they are easily degraded by electron-beams. This study aimed to investigate the electron-beam induced damage mechanisms for exfoliated Ca2Na2Nb5O16(CNNO) nanosheets. Knock-on damage dominantly occurred at high voltages, leaving short-range order in the final amorphous structure. On the other hand, a series of chemical reactions predominantly occurred at low voltages, resulting in random elemental loss and a fully disordered amorphous structure. This radiolysis was facilitated by insulated CNNO nanosheets that contained a large number of dangling bonds after the chemical solution process. The radiolysis damage kinetics was faster than knock-on damage and induced more elemental loss. Based on our understanding of the electron beam-induced degradation, atomic-scale imaging of the CNNO nanosheets was successfully performed using Cs-corrected scanning transmission electron microscopy at 300 keV with a decreased beam current. This result is of particular significance because understanding of electron-beam damage in exfoliated and insulating 2D oxide sheets could improve identification of their atomic structure using electron microscopy techniques and lead to a practical guide for further extensive characterization of doped elements and layered structures to improve their properties.

Intrinsic variation effect in memristive neural network with weight quantization.

To analyze the effect of the intrinsic variations of the memristor device on the neuromorphic system, we fabricated 32 × 32 Al2O3/TiOx-based memristor crossbar array and implemented 3 bit multilevel conductance as weight quantization by utilizing the switching characteristics to minimize the performance degradation of the neural network. The tuning operation for 8 weight levels was confirmed with a tolerance of ±4µA (±40µS). The endurance and retention characteristics were also verified, and the random telegraph noise (RTN) characteristics were measured according to the weight range to evaluate the internal stochastic variation effect. Subsequently, a memristive neural network was constructed by off-chip training with differential memristor pairs for the Modified National Institute of Standards and Technology (MNIST) handwritten dataset. The pre-trained weights were quantized, and the classification accuracy was evaluated by applying the intrinsic variations to each quantized weight. The intrinsic variations were applied using the measured weight inaccuracy given by the tuning tolerance, RTN characteristics, and the fault device yield. We believe these results should be considered when the pre-trained weights are transferred to a memristive neural network by off-chip training.

Predictors of Step Length from Surface Electromyography and Body Impedance Analysis Parameters.

Step length is a critical hallmark of health status. However, few studies have investigated the modifiable factors that may affect step length. An exploratory, cross-sectional study was performed to evaluate the surface electromyography (sEMG) and body impedance analysis (BIA) parameters, combined with individual demographic data, to predict the individual step length using the GAITRite® system. Healthy participants aged 40−80 years were prospectively recruited, and three models were built to predict individual step length. The first model was the best-fit model (R2 = 0.244, p < 0.001); the root mean square (RMS) values at maximal knee flexion and height were included as significant variables. The second model used all candidate variables, except sEMG variables, and revealed that age, height, and body fat mass (BFM) were significant variables for predicting the average step length (R2 = 0.198, p < 0.001). The third model, which was used to predict step length without sEMG and BIA, showed that only age and height remained significant (R2 = 0.158, p < 0.001). This study revealed that the RMS value at maximal strength knee flexion, height, age, and BFM are important predictors for individual step length, and possibly suggesting that strengthening knee flexor function and reducing BFM may help improve step length.