A colorimetric sensor for rapid discrimination of tea polyphenols and tea authentication based on Rh-decorated Pd nanocubes with high peroxidase-like activity.

The rapid development of nanozymes has offered substantial opportunities for the fields of biomedicine, chemical sensing, and food safety. Among these applications, multichannel sensors, with the capability of simultaneously detecting multiple target analytes, hold promise for the practical application of nanozymes in chemical sensing with high detection efficiency. In this study, Rh-decorated Pd nanocubes (Pd-Rh nanocubes) with significantly enhanced peroxidase-like activity are synthesized through the mediation of underpotential deposition (UPD) and subsequently employed to develop a multichannel colorimetric sensor for discriminating tea polyphenols (TPs) and tea authentication. Based on a single reactive unit of efficient catalytic oxidation of 3,3',5,5'-tetramethylbenzidine dihydrochloride (TMB), the nanozyme-based multichannel colorimetric sensor responds to each analyte in as short as 1 min. With the aid of principal component analysis (PCA) and hierarchical cluster analysis (HCA), various TPs and types of tea can be accurately identified. This work not only provides a new type of simply structured and highly active nanozymes but also develops a concise and rapid multichannel sensor for practical application in tea authentication and quality inspection.

Steering the Selective Production of Glycolic Acid by Electrocatalytic Oxidation of Ethylene Glycol with Nanoengineered PdBi-Based Heterodimers.

Heterodimers of metal nanocrystals (NCs) with tailored elemental distribution have emerged as promising candidates in the field of electrocatalysis, owing to their unique structures featuring heterogeneous interfaces with distinct components. Despite this, the rational synthesis of heterodimer NCs with similar elemental composition remains a formidable challenge, and their impact on electrocatalysis has remained largely elusive. In this study, Pd@Bi-PdBi heterodimer NCs are synthesized through an underpotential deposition (UPD)-directed growth pathway. In this pathway, the UPD of Bi promotes a Volmer-Weber growth mode, allowing for judicious modulation of core-satellite to heterodimer structures through careful control of supersaturation and growth kinetics. Significantly, the heterodimer NCs are employed in the electrocatalytic process of ethylene glycol (EG) with high activity and selectivity. Compared with pristine Pd octahedra and common PdBi alloy NC, the unique heterodimer structure of the Pd@Bi-PdBi heterodimer NCs endows them with the highest electrocatalytic performance of EG and the best selectivity (≈93%) in oxidizing EG to glycolic acid (GA). Taken together, this work not only heralds a new strategy for UPD-directed synthesis of bimetallic NCs, but also provides a new design paradigm for steering the selectivity of electrocatalysts.

A contactless monitoring system for accurately predicting energy expenditure during treadmill walking based on an ensemble neural network.

The monitoring of treadmill walking energy expenditure (EE) plays an important role in health evaluations and management, particularly in older individuals and those with chronic diseases. However, universal and highly accurate prediction methods for walking EE are still lacking. In this paper, we propose an ensemble neural network (ENN) model that predicts the treadmill walking EE of younger and older adults and stroke survivors with high precision based on easy-to-obtain features. Compared with previous studies, the proposed model reduced the estimation error by 13.95% and 66.20% for stroke survivors and younger adults, respectively. Furthermore, a contactless monitoring system was developed based on Kinect, mm-wave radar, and ENN algorithms, and the treadmill walking EE was monitored in real time. This ENN model and monitoring system can be combined with smart devices and treadmill, making them suitable for evaluating, monitoring, and tracking changes in health during exercise and in rehabilitation environments.

Probing local charge transfer processes of Pt-Au heterodimers in plasmon-enhanced electrochemistry by CO stripping techniques.

CO-stripping experiments are employed as a highly structure-sensitive and in situ strategy to explore the mechanisms of plasmon-enhanced electrooxidation reactions. By using Pt-Au heterodimers as a model catalyst, the plasmon-induced current and potential changes on Pt and Au sites can be identified and explained.

Single-plane osteotomy model is inaccurate for evaluating the optimal strategy in treating vertical femoral neck fractures: A finite element analysis.

BACKGROUND AND OBJECTIVES: The conventional method for simulating vertical femoral neck fractures (vFNFs) is via a vertical single-plane osteotomy (SPO) across the entire femur. However, the accuracy of SPO for evaluating the optimal internal fixation strategy (IFS) and the appropriate assessment parameters is not clear. This study thus aimed to examine the accuracy of SPO in evaluating IFSs and to identify appropriate evaluation parameters using finite element analysis. METHODS: Eighty patient-specific finite element models were developed based on CT images from eight vFNF patients. The natural fracture model was built using structural features of the affected side, while the SPO was simulated on the healthy side. Five different IFSs were applied to both the natural fracture and SPO groups. Thirteen parameters, including stress, displacement, and stiffness, were subjected to a two-way repeated measures ANOVA to determine the effect of IFSs and fracture morphology on stability. A Pearson correlation analysis was performed on varied parameters with various IFSs to identify independent parameters. Based on these independent parameters, the entropy evaluation method (EEM) score was used to rank the performance of IFSs for each patient. RESULTS: Eight of the thirteen parameters were significantly influenced by IFSs (p < 0.05), two by fracture morphology (p < 0.01), and none by the interaction between IFS and fracture morphology. In the natural fracture group, parameters including screw stress and displacement, bone cut rate (BCR), and compression effects varied independently with distinct IFSs. In the SPO group, trunk displacement, BCR, cut-out risk, and compression effects parameters changed independently. The BCR of the Alpha strategy was significantly higher than that of the Inverted strategy in the natural fracture group (p = 0.002), whereas the opposite was observed in the SPO group (p = 0.016). Regarding compression effects, two IFS pairings in the natural fracture group and seven IFS pairings in the SPO group exhibited significant differences. None of the five IFSs achieved the optimal EEM score for each patient. CONCLUSIONS: The single-plane osteotomy model may have limitations in assessing IFSs, particularly when the bone cut rate and compression effects are the main influencing factors. Parameters of the screw stress and displacement, BCR, and compression effects appear to be relevant in evaluating IFSs for natural fracture models. It indicates that individualized natural fracture models could provide more comprehensive insights for determining the optimal IFS in treating vFNFs.

Deciphering the Mechanisms of Photo-Enhanced Catalytic Activities in Plasmonic Pd-Au Heteromeric Nanozymes for Colorimetric Analysis.

The growing demand for highly active nanozymes in various fields has led to the development of several strategies to enhance their activity. Plasmonic enhancement, a strategy used in heterogenous catalysis, represents a promising strategy to boost the activity of nanozymes. Herein, Pd-Au heteromeric nanoparticles (Pd-Au dimers) with well-defined heterointerfaces have been explored as plasmonic nanozymes. As a model system, the Pd-Au dimers with integrated peroxidase (POD)-like activity and plasmonic activity are used to investigate the effect of plasmons on enhancing the activity of nanozymes under visible light irradiation. Mechanistic studies revealed that the generation of hot electron-hole pairs plays a dominant role in plasmonic effect, and it greatly enhances the decomposition of H2 O2 to the reactive oxygen species (ROS) intermediates (•OH, •O2 - and 1 O2 ), leading to elevated POD-like activity of the Pd-Au dimers. Finally, the Pd-Au dimers are applied in the plasmon-enhanced colorimetric method for the detection of alkaline phosphatase, exhibiting broad linear range and low detection limit. This study not only provides a straightforward approach for regulating nanozyme activity through plasmonic heterostructures but also sheds light on the mechanism of plasmon-enhanced catalysis of nanozymes.

A biomechanical evaluation of firefighters' musculoskeletal loads when carrying self-contained breathing apparatus in walking and running.

INTRODUCTION: Musculoskeletal loading data are needed to design ergonomic intervention for firefighters. This study aimed to quantify the firefighters' musculoskeletal loads during self-contained breathing apparatus (SCBA) carriage and evaluate the effectiveness of shoulder strap length variation for the prevention of SCBA-related injuries. METHOD: Twelve firefighters (height: 174.6 ±â€¯2.4 cm, mass: 67 ±â€¯3.5 kg, BMI = 22 ±â€¯1 kg/m2) participated the walking and running protocols with no SCBA equipped and three varying-strapped SCBAs conditions. Joint range of motion and surface electromyography (sEMG) were synchronously measured. Subsequently, joint kinematics was inputted for subject-specific musculoskeletal modeling to estimate muscle forces and joint reaction forces, while the sEMG was used to validate the model. Repeated measures analysis of variance was used for the main effects (p < 0.05). Independent samples t-test was performed to determine differences between walking and running. RESULTS: Walking with SCBA increased the rectus femoris force and hip reaction force by 34.92% [F = 53.629; p < 0.001; η2 = 0.317] and 34.71% [F = 53.653; p < 0.001; η2 = 0.517], the growth rate was 54.2% [F = 76.487; p < 0.001; η2 = 0.418] and 51.19% [F = 69.201; p < 0.001; η2 = 0.652] during running, respectively. Running with SCBA significantly increased the knee reaction force by 63.04% [F = 83.960; p < 0.001; η2 = 0.797], while only 18.49% increase during walking. Adjusting SCBA shoulder strap length significantly altered the rectus abdominis force and L4/L5 reaction force during walking and running. CONCLUSIONS: Results revealed that rectus femoris activity, hip and knee exertion was sensitive to SCBA carriage. The variation of shoulder strap length has potential to influence the risk of low back pain (LBP). PRACTICAL APPLICATIONS: The findings suggest that fire services promote targeting physical training at firefighters' hip and knee regions. Test firefighters in this study were not advisable to adjust their shoulder strap at loose-fitting condition. The compatibility design of the trunk morphology and SCBA back-mounted frame was suggested for the management of LBP.

Boosting plasmon-enhanced electrochemistry by in situ surface cleaning of plasmonic nanocatalysts.

The application of surface plasmons in heterogeneous catalysis has attracted widespread attention due to their promising potential for harvesting solar energy. The effect of surface adsorbates on catalysts has been well documented in many traditional reactions; nonetheless, their role in plasmonic catalysis has been rarely studied. In this study, an in situ electrochemical surface cleaning strategy is developed and the influence of surface adsorbates on plasmon-enhanced electrochemistry is investigated. Taking Au nanocubes as an example, plasmonic catalysts with clean surfaces are obtained by Cu2O coating and in situ electrochemical etching. During this process, the surface adsorbates of Au nanocubes are removed together with the Cu2O shells. The Au nanocubes with clean surfaces exhibit remarkable performance in plasmon-enhanced electrooxidation of glucose and an enhancement of 445% is demonstrated. The Au NCs with clean surfaces can not only provide more active sites but also avoid halides as hole scavengers, and therefore, the efficient utilization of hot holes by plasmonic excitation is achieved. This process is also generalized to other molecules and applied in electrochemical sensing with high sensitivity. These results highlight the critical role of surface adsorbates in plasmonic catalysis and may forward the design of efficient plasmonic catalysts for plasmon-enhanced electrochemistry.

Numerical Simulation of the Effect of Different Footwear Midsole Structures on Plantar Pressure Distribution and Bone Stress in Obese and Healthy Children.

The foot, as the foundation of the human body, bears the vast majority of the body's weight. Obese children bear more weight than healthy children in the process of walking and running. This study compared three footwear midsole structures (solid, lattice, and chiral) based on plantar pressure distribution and bone stress in obese and healthy children through numerical simulation. The preparation for the study included obtaining a thin-slice CT scan of a healthy 9-year-old boy's right foot, and this study distinguished between a healthy and an obese child by applying external loadings of 25 kg and 50 kg in the finite element models. The simulation results showed that the plantar pressure was mainly concentrated in the forefoot and heel due to the distribution of gravity (first metatarsal, fourth metatarsal, and heel bone, corresponding to plantar regions M1, M4, and HM and HL) on the foot in normal standing. Compared with the lattice and solid EVA structures, in both healthy and obese children, the percentage reduction in plantar pressure due to the chiral structure in the areas M1, M4, HM, and HL was the largest with values of 38.69%, 34.25%, 64.24%, and 54.03% for an obese child and 33.99%, 28.25%, 56.08%, and 56.96% for a healthy child. On the other hand, higher pressures (15.19 kPa for an obese child and 5.42 kPa for a healthy child) were observed in the MF area when using the chiral structure than when using the other two structures, which means that this structure can transfer an amount of pressure from the heel to the arch, resulting in a release in the pressure at the heel region and providing support at the arch. In addition, the study found that the chiral structure was not highly sensitive to the external application of body weight. This indicates that the chiral structure is more stable than the other two structures and is minimally affected by changes in external conditions. The findings in this research lay the groundwork for clinical prevention and intervention in foot disorders in obese children and provide new research ideas for shoe midsole manufacturers.

Effectiveness of social media with or without wearable devices to improve physical activity and reduce sedentary behavior: A randomized controlled trial of Chinese postgraduates.

The present study was aimed to verify whether an integrating of wearable activity tracker device and a social media intervention strategy would be better than a standalone social media intervention for improving physical activity (PA) and reducing sedentary time for Chinese postgraduate population. A total of 42 full-time postgraduate students participated in this study, which were randomized to receive a 4-week social media intervention through WeChat either with (Wearable Device group) or without (control group) a wearable activity tracker device. Energy expenditure, step counts, moderate to vigorous physical activity time (MVPA) and sedentary time were assessed before and after the intervention. Besides, anthropometric parameters of body weight, body mass index, body fat rate, waist-to-hip ratio, as well as self-reported quality of life were also evaluated. It was found that both energy expenditure and step counts were significantly increased, while sedentary time was significantly reduced during the post-intervention test compared to the baseline test for Wearable Device group. No significant difference of PA was found for the control group. The results demonstrated that the integrating of wearable activity tracker device and a social media intervention was effective in promoting PA, while a standalone social media intervention may have no effect on the influence of PA for Chinese postgraduates.

Engineering the Intrinsic Chirality of Plasmonic Au@Pd Metamaterials for Highly Sensitive Chiroplasmonic Hydrogen Sensing.

Metal helicoid nanoparticles with intrinsic 3D chiral structures have emerged as a new class of plasmonic metamaterials with outstanding chiroplasmonic properties. Despite the considerable potential of metal helicoid nanoparticles in chiroplasmonic sensing, their sensing capabilities remain elusive, stressing the need for the rational chirality engineering of helicoid nanoparticles. In this report, Au@Pd helicoid nanoparticles with engineered chiroplasmonic properties and integrated hydrogen sensing capabilities are rationally synthesized. As chiroplasmonic metamaterials, the Au@Pd helicoid nanoparticles exhibit unprecedented sensitivity for hydrogen chiroplasmonic sensing in the visible range. A significant circular dichroism red-shift as large as 206.1 nm can be achieved when they are exposed to hydrogen. Such a high sensitivity outperforms all the plasmonic hydrogen sensors in the visible range. Besides sensitivity, the chiroplasmonic sensing platform shows a good linear range of 1.5-6.0% hydrogen concentration with higher figure of merit, excellent selectivity, and good reusability. To further demonstrate its applicability, this chiroplasmonic hydrogen sensing platform is utilized to investigate hydrogen absorption and desorption kinetics on Pd. This study heralds a new paradigm for plasmonic hydrogen sensing and highlights the tremendous potential of utilizing helicoid nanoparticles as chiroplasmonic sensing metamaterials by chirality engineering.

Surface Topographical Engineering of Chiral Au Nanocrystals with Chiral Hot Spots for Plasmon-Enhanced Chiral Discrimination.

Surface roughness in chiral plasmonic nanostructures generates asymmetrical localized electromagnetic fields, which hold great promise for applications in chiral recognition, chiroptical spectroscopic sensing, and enantioselective photocatalysis. In this study, we develop a surface topographical engineering approach to precisely manipulate the surface structures of chiral Au nanocrystals. Through carefully controlling the amounts of l- or d-cystine (Cys) and the seed solution in the growth process, we successfully synthesize chiral Au nanocrystals with highly disordered, ordered, and less ordered wrinkled surfaces. An underlying principle governing the relationship between surface roughness, orderliness, and chiroptical response is also proposed. More importantly, the chiral ordered wrinkles on the surfaces of the nanocrystals generate asymmetrical localized electronic fields with enhanced intensity, which achieve excellent plasmon-enhanced chiral discrimination ability for penicillamine (Pen) enantiomers. This work offers exciting prospects for manipulating the surface structures of chiral nanocrystals and designing highly sensitive plasmon-enhanced enantioselective sensors with chiral hot spots.

Silver decahedral nanoparticles with uniform and adjustable sizes for surface-enhanced Raman scattering-based thiram residue detection.

Surface-enhanced Raman scattering (SERS) has been widely used as a sensitive molecular spectroscopy technology in food safety detection. Precise morphology control of plasmonic nanoparticles for high sensitivity and high uniformity SERS substrates remains challenging. Herein, silver decahedral nanoparticles (AgDeNPs) with uniform and adjustable sizes were synthesized by a photochemical seed-mediated method and utilized as SERS substrates for pesticide residue detection. The SERS sensitivity was demonstrated by using 4-mercaptobenzoic acid (4-MBA) as a typical model molecule, and the limit of detection (LOD) reached 1.0 × 10-13 M. The pesticide residue detection of thiram in aqueous solution and on fruit peels was successfully realized; the LODs were 1.0 × 10-11 M and 0.96 ng cm-2, respectively, and SERS repeatability was also proved. Overall, size-tunable AgDeNPs show attractive SERS performances and are expected to hold potential application in sensitive food and environmental safety detection.

Preparation and evaluation of dissolving tofacitinib microneedles for effective management of rheumatoid arthritis.

Dissolving microneedles have become a focal point in transdermal drug delivery. They have the advantages of painless, rapid drug delivery and high drug utilization. The purpose of this study was to evaluate the efficacy of Tofacitinib citrate microneedles in arthritis treatment, assess the dose-effect relationship, and determine the cumulative penetration during percutaneous injection. In this study, block copolymer was utilized to prepare the dissolving microneedles. The microneedles were characterized through skin permeation tests, dissolution tests, treatment effect evaluations, and Western blot experiments. In vivo dissolution experiments revealed that the soluble microneedles completely dissolved within 2.5 min, while in vitro skin permeation experiments demonstrated the highest unit area of skin permeation of the microneedles reached 2118.13 mg/cm2. The inhibition of Tofacitinib microneedle on joint swelling in rats with Rheumatoid arthritis was better than Ketoprofen and close to that of oral Tofacitinib. Western-blot experiment comfirmed the Tofacitinib microneedle's inhibitory effect on the JAK-STAT3 pathway in rats with Rheumatoid arthritis. In conclusion, Tofacitinib microneedles effectively inhibited arthritis in rats, demonstrating potential for Rheumatoid arthritis treatment.

Modulate the metallic Sb state on ultrathin PdSb-based nanosheets for efficient formic acid electrooxidation.

Incorporation of oxophilic metals into Pd-based nanostructures has shown great potential in small molecule electrooxidation owing to their superior anti-poisoning capability. However, engineering the electronic structure of oxophilic dopants in Pd-based catalysts remains challenging and their impact on electrooxidation reactions is rarely demonstrated. Herein, we have developed a method for synthesizing PdSb-based nanosheets, enabling the incorporation of the Sb element in a predominantly metallic state despite its high oxophilic nature. Moreover, the Pd90Sb7W3 nanosheet serves as an efficient electrocatalyst for the formic acid oxidation reaction (FAOR), and the underlying promotion mechanism is investigated. Among the as-prepared PdSb-based nanosheets, the Pd90Sb7W3 nanosheet exhibits a remarkable 69.03% metallic state of Sb, surpassing the values observed for the Pd86Sb12W2 (33.01%) and Pd83Sb14W3 (25.41%) nanosheets. X-ray photoelectron spectroscopy (XPS) and CO stripping experiments confirm that the Sb metallic state contributes the synergistic effect of their electronic and oxophilic effect, thus leading to an effective electrooxidation removal of CO and significantly enhanced FAOR electrocatalytic activity (1.47 A mg-1; 2.32 mA cm-1) compared with the oxidated state of Sb. This work highlights the importance of modulating the chemical valence state of oxophilic metals to enhance electrocatalytic performance, offering valuable insights for the design of high-performance electrocatalysts for electrooxidation of small molecules.

Characteristics of corticomuscular coupling during wheelchair Tai Chi in patients with spinal cord injury.

BACKGROUND: Wheelchair Tai Chi (WCTC) has been proved to have benefits for the brain and motor system of spinal cord injury (SCI) patients. However, the characteristics of corticomuscular coupling during WCTC are scarcely known. We aimed to investigate changes following SCI on corticomuscular coupling, and further compare the coupling characteristics of WCTC with aerobic exercise in SCI patients. METHODS: A total of 15 SCI patients and 25 healthy controls were recruited. The patients had to perform aerobic exercise and WCTC, while healthy controls needed to complete a set of WCTC. The participants accomplished the test following the tutorial video in a sitting position. The upper limb muscle activation was measured from upper trapezius, medial deltoid, biceps brachii and triceps brachii with surface electromyography. Cortical activity in the prefrontal cortex, premotor cortex, supplementary motor area and primary motor cortex was simultaneously collected by functional near-infrared spectroscopy. The functional connectivity, phase synchronization index and coherence values were then calculated and statistically analyzed. RESULTS: Compared to healthy controls, changes in functional connectivity and higher muscle activation were observed in the SCI group. There was no significant difference in phase synchronization between groups. Among patients, significantly higher coherence values between the left biceps brachii as well as the right triceps brachii and contralateral regions of interest were found during WCTC than during aerobic exercise. CONCLUSION: The patients may compensate for the lack of corticomuscular coupling by enhancing muscle activation. This study demonstrated the potential and advantages of WCTC in eliciting corticomuscular coupling, which may optimize rehabilitation following SCI.

Te-induced fabrication of Pt3PdTe0.2 alloy nanocages by the self-diffusion of Pd atoms with unique MOR electrocatalytic performance.

The key to the application of direct methanol fuel cells is to improve the activity and durability of Pt-based catalysts. Based on the upshift of the d-band centre and exposure to more Pt active sites, Pt3PdTe0.2 catalysts with significantly enhanced electrocatalytic performance for the methanol oxidation reaction (MOR) were designed in this study. A series of different Pt3PdTex (x = 0.2, 0.35, and 0.4) alloy nanocages with hollow and hierarchical structures were synthesized using cubic Pd nanoparticles as sacrificial templates and PtCl62- and TeO32- metal precursors as oxidative etching agents. The Pd nanocubes were oxidized into an ionic complex, which was further co-reduced with Pt and Te precursors by reducing agents to form the hollow Pt3PdTex alloy nanocages with a face-centred cubic lattice. The sizes of the nanocages were around 30-40 nm, which were larger than the Pd templates (18 nm) and the thicknesses of the walls were 7-9 nm. The Pt3PdTe0.2 alloy nanocages exhibited the highest catalytic activities and stabilities toward the MOR after electrochemical activation in sulfuric acid solution. CO-stripping tests suggested the enhanced CO-tolerant ability due to the doping of Te. The specific activity of Pt3PdTe0.2 for the MOR reached 2.71 mA cm-2 in acidic conditions, which was higher than those of Pd@Pt core-shell and PtPd1.5 alloy nanoparticles and commercial Pt/C. A DMFC with Pt3PdTe0.2 as the anodic catalyst output a higher power density by 2.6 times than that of commercial Pt/C, demonstrating its practicable application in clean energy conversions. Density functional theory (DFT) confirmed that the alloyed Te atoms altered the electron distributions of Pt3PdTe0.2, which could lower the Gibbs free energy of the rate-determining methanol dehydrogenation step and greatly improve the MOR catalytic activity and durability.

Metallic Heterostructures for Plasmon-Enhanced Electrocatalysis.

Metallic heterogeneous nanostructures with plasmonic functionality have attracted great attention in the field of plasmon-enhanced electrocatalysis, where surface plasmons produced under light excitation could facilitate the overall electrocatalytic performances. Owing to their controllability, multifunctionality, and complexity, heterogeneous metallic nanostructures take advantages of the properties from individual components and synergistic effects from adjacent components, thus may achieve remarkable electrocatalytic performances. This review highlights the state-of-the-art progress of the application of metallic heterostructures for plasmon-enhanced electrocatalysis. First, a brief introduction to plasmonic heterogeneous nanostructures is demonstrated. Then, fundamental principles of localized surface plasmon resonance and the underlying mechanisms of plasmonic heterogeneous nanostructures in catalysis are discussed. This is followed by a discussion of recent advances of plasmonic heterogeneous nanostructures in plasmon-enhanced electrocatalysis, in which the enhanced activity, selectivity, and stability are particularly emphasized. Finally, an outlook of remaining challenges and future opportunities for plasmonic heterogeneous nanomaterials and plasmon-related electrocatalysis is presented.