The O-Defective g-ZnO Sensor for VOC Gases: The Adsorption-Desorption, Electronic, and Sensitivity Properties.

Adsorption-desorption performance, electronic properties, and sensitivity of O-defective g-ZnO (ODZO) gas sensors for volatile organic compounds (VOCs) are calculated using density functional theory and nonequilibrium Green's formalism. The VOCs are CH2O, CH4, C2H4O, CH4O, and C2H6. The intrinsic g-ZnO (IZO) and ODZO exhibit strong adsorption capabilities for C2H4O and CH4O. The IZO (0.118 e) and ODZO (0.059 e), which act as electron donors, exhibit the highest charge transfer to CH2O, indicating a strong interaction. The VOCs adsorption on the IZO and ODZO systems maintain nonmagnetic semiconductor characteristics. Additionally, the introduction of an O-defect causes the adsorption energy and charge transfer amount of ODZO to show an overall decrease, indicating better desorption ability. Notably, the sensitivity results show that the ODZO gas sensors exhibit high sensitivity to CH2O (39.3%), C2H4O (29.0%), and CH4O (19.6%) at a voltage of 2.6 V, consistent with the adsorption-desorption performance and electronic properties.

Leveraging Transfer Superposition Theory for StableState Visual Evoked Potential Cross-Subject Frequency Recognition.

In steady-state visual evoked potential (SSVEP)based brain-computer interfaces (BCIs), various spatial filtering methods based on individual calibration data have been proposed to alleviate the interference of spontaneous activities in SSVEP signals for enhancing the SSVEP detection performance. However, the necessary calibration procedures take time, cause visual fatigue and reduce usability. For the calibration-free scenario, we propose a cross-subject frequency identification method based on transfer superimposed theory for SSVEP frequency decoding. First, a multi-channel signal decomposition model was constructed. Next, we used the cross least squares iterative method to create individual specific transfer spatial filters as well as source subject transfer superposition templates in the source subject. Then, we identified common knowledge among source subjects using a prototype spatial filter to make common transfer spatial filters and common impulse responses. Following, we reconstructed a global transfer superimposition template with SSVEP frequency characteristics. Finally, an ensemble cross-subject transfer learning method was proposed for SSVEP frequency recognition by combining the sourcesubject transfer mode, the global transfer mode, and the sinecosine reference template. Offline tests on two public datasets show that the proposed method significantly outperforms the FBCCA, TTCCA, and CSSFT methods. More importantly, the proposed method can be directly used in online SSVEP recognition without calibration. The proposed algorithm was robust, which is important for a practical BCI.

Heterojunction photoelectric device with fast response speed and low power consumption composed of WSSe and AlN.

Through the accurate calculation of density functional theory, reveal the excellent photoelectric properties of the AlN/WSSe and WSSe/AlN heterojunction. Especially, the hole mobility of the AlN/WSSe heterojunction is as high as 3919 cm²/Vs in armchair direction, and the hole mobility of the WSSe/AlN heterojunction is as high as 4422 cm²/Vs in the zigzag direction. Interestingly, when two H atoms are adsorbed in the WSSe surface, the Gibbs free energy change are -0.093 eV and -0.984 eV, which tends to zero, which can promote the spontaneous reaction of electrocatalytic water decomposition to produce H2. In addition, the AlN/WSSe heterojunction exhibits significant photoelectric effect photocurrent (1.15 a02/photon) in the armchair direction and the heterojunctions have lower threshold voltage (1.5 V), that indicate the AlN/WSSe and WSSe/AlN heterojunction have great application prospect in manufacturing high-performance optoelectronic devices with fast response and low power consumption. .

Historical evolution of basic characteristics, underlying causes, and management tools of food fraud in China: 1949-2022.

The emergence and development of food fraud are closely related to a country's economic system and social development. It has distinct characteristics in different historical stages, and an inherent historical logic links different historical stages. Following the thread of "what", "why", and "what to do", this study uses a broad perspective and comparative historical approach to examine the evolution of the basic characteristics, underlying causes, and management tools of food fraud in China at different historical stages over 70 years from 1949 to 2022. This study argues that the historical evolution of food fraud in China has characteristics unique to China as well as features similar to those in other countries. It provides a window for academics to understand the historical evolution of food fraud in China. It also provides valuable insights for other countries, especially developing countries, for objectively understanding the evolution of food fraud during their economic development process, and how to address it.

Color tuning by Si/Ge substitution in Cr4+ doped melilite inorganic pigments.

Rockery constitutes one of the significant elements of Chinese royal garden design, and it becomes an emerging interdisciplinary topic covering both science and art. In this work, we report an attempt to restore the color of the ancient rockeries by finding the appropriate inorganic pigments. Chromium is doped as activators into strontium melilites with varying Si/Ge ratio, and the synthesized powders give a series of color changing from ice blue to dark-sea green. With the structure and spectroscopic characterizations, we discuss the substitutions of Cr in Mg/Si/Ge sites of the melilite host. The Tanabe-Sugano diagram of 3d2 configuration is employed to explain the change of diffuse reflectance spectra caused by Si/Ge substitution. With the work, we hope to inspire the interdisciplinary research and promote the rockery heritage restoration and protection.

The ubiquitin E3 ligase APC/CCdc20 mediates mitotic degradation of OGT.

O-linked ß-N-acetylglucosamine (O-GlcNAc) transferase (OGT) is the sole enzyme that catalyzes all O-GlcNAcylation reactions intracellularly. Previous investigations have found that OGT levels oscillate during the cell division process. Specifically, OGT abundance is downregulated during mitosis, but the underlying mechanism is lacking. Here we demonstrate that OGT is ubiquitinated by the ubiquitin E3 ligase, anaphase promoting complex/cyclosome (APC/C)-cell division cycle 20 (Cdc20). We show that APC/CCdc20 interacts with OGT through a conserved destruction box (D-box): Arg-351/Leu-354, the abrogation of which stabilizes OGT. As APC/CCdc20-substrate binding is often preceded by a priming ubiquitination event, we also used mass spectrometry and mapped OGT Lys-352 to be a ubiquitination site, which is a prerequisite for OGT association with APC/C subunits. Interestingly, in The Cancer Genome Atlas, R351C is a uterine carcinoma mutant, suggesting that mutations of the D-box are linked with tumorigenesis. Paradoxically, we found that both R351C and the D-box mutants (R351A/L354A) inhibit uterine carcinoma in mouse xenograft models, probably due to impaired cell division and proliferation. In sum, we propose a model where OGT Lys-352 ubiquitination primes its binding with APC/C, and then APC/CCdc20 partners with OGT through the D-box for its mitotic destruction. Our work not only highlights the key mechanism that regulates OGT during the cell cycle, but also reveals the mutual coordination between glycosylation and the cell division machinery.

A cross-dataset adaptive domain selection transfer learning framework for motor imagery-based brain-computer interfaces.

Objective. In brain-computer interfaces (BCIs) that utilize motor imagery (MI), minimizing calibration time has become increasingly critical for real-world applications. Recently, transfer learning (TL) has been shown to effectively reduce the calibration time in MI-BCIs. However, variations in data distribution among subjects can significantly influence the performance of TL in MI-BCIs.Approach.We propose a cross-dataset adaptive domain selection transfer learning framework that integrates domain selection, data alignment, and an enhanced common spatial pattern (CSP) algorithm. Our approach uses a huge dataset of 109 subjects as the source domain. We begin by identifying non-BCI illiterate subjects from this huge dataset, then determine the source domain subjects most closely aligned with the target subjects using maximum mean discrepancy. After undergoing Euclidean alignment processing, features are extracted by multiple composite CSP. The final classification is carried out using the support vector machine.Main results.Our findings indicate that the proposed technique outperforms existing methods, achieving classification accuracies of 75.05% and 76.82% in two cross-dataset experiments, respectively.Significance.By reducing the need for extensive training data, yet maintaining high accuracy, our method optimizes the practical implementation of MI-BCIs.

A rare case of left atrial appendage aneurysm.

BACKGROUND: Left atrial appendage aneurysm is a rare cardiac mass, with only a few cases reported. There are usually no specific symptoms, and a few patients visit the doctor with symptoms. CASE PRESENTATION: A 20-year-old male presented to our hospital with a "pericardial cyst found by medical evaluation in another hospital for 2 years." Cardiac ultrasound performed at clinics of our hospital suggested a cystic dark area in the left ventricular lateral wall and the anterior lateral wall, consistent with a pericardial cyst and mild mitral regurgitation. After further relevant examinations and ruling out contraindications, an excision of the left atrial appendage aneurysm was performed under general anesthesia and cardiopulmonary bypass with beating-heart. The postoperative pathological results identified that: (left atrial appendage) fibrocystic wall-like tissue with a focal lining of the flat epithelium, consistent with a benign cyst. CONCLUSION: Left atrial appendage aneurysms are rare and insidious. They are usually found by chance during medical evaluations. If the location is not good or the volume is too large, then compression symptoms or arrhythmia, thrombosis and other concomitant symptoms will occur. Surgical resection is presently the only effective radical cure for a left atrial appendage aneurysm.

Leveraging temporal dependency for cross-subject-MI BCIs by contrastive learning and self-attention.

Brain-computer interfaces (BCIs) built based on motor imagery paradigm have found extensive utilization in motor rehabilitation and the control of assistive applications. However, traditional MI-BCI systems often exhibit suboptimal classification performance and require significant time for new users to collect subject-specific training data. This limitation diminishes the user-friendliness of BCIs and presents significant challenges in developing effective subject-independent models. In response to these challenges, we propose a novel subject-independent framework for learning temporal dependency for motor imagery BCIs by Contrastive Learning and Self-attention (CLS). In CLS model, we incorporate self-attention mechanism and supervised contrastive learning into a deep neural network to extract important information from electroencephalography (EEG) signals as features. We evaluate the CLS model using two large public datasets encompassing numerous subjects in a subject-independent experiment condition. The results demonstrate that CLS outperforms six baseline algorithms, achieving a mean classification accuracy improvement of 1.3 % and 4.71 % than the best algorithm on the Giga dataset and OpenBMI dataset, respectively. Our findings demonstrate that CLS can effectively learn invariant discriminative features from training data obtained from non-target subjects, thus showcasing its potential for building models for new users without the need for calibration.

Polydopamine-Coated Kaempferol-Loaded MOF Nanoparticles: A Novel Therapeutic Strategy for Postoperative Neurocognitive Disorder.

Purpose: The primary objective of this study was to develop an innovative nanomedicine-based therapeutic strategy to alleviate Postoperative Neurocognitive Disorder (PND) in patients undergoing surgery. Patients and Methods: To achieve this goal, polydopamine-coated Kaempferol-loaded Metal-Organic Framework nanoparticles (pDA/KAE@ZIF-8) were synthesized and evaluated. The study involved encapsulating Kaempferol (KAE) within ZIF-8 nanoparticles, followed by coating with polydopamine (PDA) to enhance biocompatibility and targeted delivery. The characterization of these nanoparticles (NPs) was conducted using various techniques including Scanning Electron Microscopy, Fourier-Transform Infrared Spectroscopy, X-ray Diffraction, and Ultraviolet-Visible spectroscopy. The efficacy of pDA/KAE@ZIF-8 NPs was tested in both in vitro and in vivo models, specifically focusing on their ability to penetrate the blood-brain barrier and protect neuronal cells against oxidative stress. Results: The study found that pDA/KAE@ZIF-8 NPs efficiently penetrated the blood-brain barrier and were significantly taken up by neuronal cells. These nanoparticles demonstrated remarkable Reactive Oxygen Species (ROS) scavenging capabilities and stability under physiological conditions. In vitro studies showed that pDA/KAE@ZIF-8 NPs provided protection to HT-22 neuronal cells against H2O2-induced oxidative stress, reduced the levels of pro-inflammatory cytokines, and decreased apoptosis rates. In a PND mouse model, the treatment with pDA/KAE@ZIF-8 NPs significantly improved cognitive functions, surpassing the effects of KAE alone. This improvement was substantiated through behavioral tests and a noted reduction in hippocampal inflammation. Conclusion: The findings from this study underscore the potential of pDA/KAE@ZIF-8 NPs as an effective nanotherapeutic agent for PND. This approach offers a novel direction in the postoperative care of elderly patients, with the potential to transform the therapeutic landscape for neurocognitive disorders following surgery. The application of nanotechnology in this context opens new avenues for more effective and targeted treatments, thereby improving the quality of life for patients suffering from PND.

Nanoporous Carbon Materials Derived from Zanthoxylum Bungeanum Peel and Seed for Electrochemical Supercapacitors.

In order to prepare biomass-derived carbon materials with high specific capacitance at a low activation temperature (≤700 °C), nanoporous carbon materials were prepared from zanthoxylum bungeanum peels and seeds via the pyrolysis and KOH-activation processes. The results show that the optimal activation temperatures are 700 °C and 600 °C for peels and seeds. Benefiting from the hierarchical pore structure (micropores, mesopores, and macropores), the abundant heteroatoms (N, S, and O) containing functional groups, and plentiful electrochemical active sites, the PAC-700 and SAC-600 derive the large capacities of ~211.0 and ~219.7 F g-1 at 1.0 A g-1 in 6 M KOH within the three-electrode configuration. Furthermore, the symmetrical supercapacitors display a high energy density of 22.9 and 22.4 Wh kg-1 at 7500 W kg-1 assembled with PAC-700 and SAC-600, along with exceptional capacitance retention of 99.1% and 93.4% over 10,000 cycles at 1.0 A g-1. More significantly, the contribution here will stimulate the extensive development of low-temperature activation processes and nanoporous carbon materials for electrochemical energy storage and beyond.

Association between Body Mass Index and Early Renal Function after Kidney Transplantation: Observational and Mendelian Randomization Study.

INTRODUCTION: The relationship between BMI and early renal function recovery after kidney transplantation is important due to the rising global obesity rates. METHODS: A retrospective study on 320 patients who received allograft kidney transplantation at Guangxi Medical University Hospital explored the BMI-kidney function relationship using various statistical methods. Mendelian randomization (MR) was also employed to investigate causality. RESULTS: Based on the univariate analysis, multivariate linear regression models, and trend analysis, it was found that there were significant positive correlations between BMI and creatinine, urea, and cystatin C on the 7th day after kidney transplantation (p < 0.05). The sensitivity analysis further confirmed these correlations in different gender stratification, adolescents, and adults. However, the positive correlation with cystatin C was only significant in males. Additionally, after conducting smooth curve fitting analysis and threshold saturation analysis, it was revealed that the negative correlation between early renal function recovery was most significant when BMI was between 22.0 and 25.5 kg/m2, and early postoperative renal function may be optimal when BMI was at 22.2 kg/m2. Finally, the MR analysis confirmed a causal relationship between BMI and renal failure, as indicated by the IVW method (p = 0.003), as well as the weighted median estimator (p = 0.004). CONCLUSION: This study on kidney transplant patients found that maintaining a BMI within the range of 22.0-25.5 kg/m2, with an optimal BMI of 22.2 kg/m2, improves early renal function recovery. This correlation holds true for different age-groups and genders. Monitoring and controlling BMI in high-risk patients can enhance post-transplantation renal function.

Targeted desialylation and cytolysis of tumour cells by fusing a sialidase to a bispecific T-cell engager.

Bispecific T-cell engagers (BiTEs) bring together tumour cells and cytotoxic T cells by binding to specific cell-surface tumour antigens and T-cell receptors, and have been clinically successful for the treatment of B-cell malignancies. Here we show that a BiTE-sialidase fusion protein enhances the susceptibility of solid tumours to BiTE-mediated cytolysis of tumour cells via targeted desialylation-that is, the removal of terminal sialic acid residues on glycans-at the BiTE-induced T-cell-tumour-cell interface. In xenograft and syngeneic mouse models of leukaemia and of melanoma and breast cancer, and compared with the parental BiTE molecules, targeted desialylation via the BiTE-sialidase fusion proteins enhanced the formation of immunological synapses, T-cell activation and T-cell-mediated tumour-cell cytolysis in the presence of the target antigen. The targeted desialylation of tumour cells may enhance the potency of therapies relying on T-cell engagers.

A Time-Local Weighted Transformation Recognition Framework for Steady State Visual Evoked Potentials Based Brain-Computer Interfaces.

Canonical correlation analysis (CCA), Multivariate synchronization index (MSI), and their extended methods have been widely used for target recognition in Brain-computer interfaces (BCIs) based on Steady State Visual Evoked Potentials (SSVEP), and covariance calculation is an important process for these algorithms. Some studies have proved that embedding time-local information into the covariance can optimize the recognition effect of the above algorithms. However, the optimization effect can only be observed from the recognition results and the improvement principle of time-local information cannot be explained. Therefore, we propose a time-local weighted transformation (TT) recognition framework that directly embeds the time-local information into the electroencephalography signal through weighted transformation. The influence mechanism of time-local information on the SSVEP signal can then be observed in the frequency domain. Low-frequency noise is suppressed on the premise of sacrificing part of the SSVEP fundamental frequency energy, the harmonic energy of SSVEP is enhanced at the cost of introducing a small amount of high-frequency noise. The experimental results show that the TT recognition framework can significantly improve the recognition ability of the algorithms and the separability of extracted features. Its enhancement effect is significantly better than the traditional time-local covariance extraction method, which has enormous application potential.

Highly Sensitive and Selective Defect WS2 Chemical Sensor for Detecting HCHO Toxic Gases.

The gas sensitivity of the W defect in WS2 (VW/WS2) to five toxic gases-HCHO, CH4, CH3HO, CH3OH, and CH3CH3-has been examined in this article. These five gases were adsorbed on the VW/WS2 surface, and the band, density of state (DOS), charge density difference (CDD), work function (W), current-voltage (I-V) characteristic, and sensitivity of adsorption systems were determined. Interestingly, for HCHO-VW/WS2, the energy level contribution of HCHO is closer to the Fermi level, the charge transfer (B) is the largest (0.104 e), the increase in W is more obvious than other adsorption systems, the slope of the I-V characteristic changes more obviously, and the calculated sensitivity is the highest. To sum up, VW/WS2 is more sensitive to HCHO. In conclusion, VW/WS2 has a great deal of promise for producing HCHO chemical sensors due to its high sensitivity and selectivity for HCHO, which can aid in the precise and efficient detection of toxic gases.

Delineation and authentication of ferroptosis genes in ventilator-induced lung injury.

BACKGROUND: Mechanical ventilation, a critical support strategy for individuals enduring severe respiratory failure and general anesthesia, paradoxically engenders ventilator-induced lung injury (VILI). Ferrostatin-1 mitigates lung injury via ferroptosis inhibition, yet the specific ferroptosis genes contributing significantly to VILI remain obscure. METHODS: Leveraging the Gene Expression Omnibus database, we acquired VILI-associated datasets and identified differentially expressed genes (DEGs). To identify the hub genes, we constructed a protein-protein interaction network and used three parameters from CytoHubba. Consequently, we identified hub genes and ferroptosis genes as ferroptosis hub genes for VILI (VFHGs). We conducted enrichment analysis and established receiver operating characteristic (ROC) curves for VFHGs. Subsequently, to confirm the correctness of the VFHGs, control group mice and VILI mouse models, as well as external dataset validation, were established. For further research, a gene-miRNA network was established. Finally, the CIBERSORT algorithm was used to fill the gap in the immune infiltration changes in the lung during VILI. RESULTS: We identified 64 DEGs and 4 VFHGs (Il6,Ptgs2,Hmox1 and Atf3) closely related to ferroptosis. ROC curves demonstrated the excellent diagnostic performance of VFHGs in VILI. PCR and external dataset validation of the VILI model demonstrated the accuracy of VFHGs. Subsequently, the gene-miRNA network was successfully established. Ultimately, an Immune cell infiltration analysis associated with VILI was generated. CONCLUSIONS: The results emphasize the importance of 4 VFHGs and their involvement in ferroptosis in VILI, confirming their potential as diagnostic biomarkers for VILI.

Immune characteristics of kidney transplant recipients with acute respiratory distress syndrome induced by COVID-19 at single-cell resolution.

BACKGROUND: COVID-19-induced acute respiratory distress syndrome (ARDS) can result in tissue damage and multiple organ dysfunction, especially in kidney transplant recipients (KTRs) receiving immunosuppressive drugs. Presently, single-cell research on COVID-19-induced ARDS is considerably advanced, yet knowledge about ARDS in KTRs is still constrained. METHODS: Single-cell RNA sequencing (scRNA-seq) analysis was performed to construct a comprehensive single-cell immune landscape of the peripheral blood mononuclear cells (PBMCs) of eight patients with COVID-19-induced ARDS, five KTRs with COVID-19-induced ARDS, and five healthy individuals. Subsequently, we conducted a comprehensive bioinformatics analysis, including cell clustering, enrichment analysis, trajectory analysis, gene regulatory network analysis, and cell-cell interaction analysis, to investigate the heterogeneity of the immune microenvironment in KTRs with ARDS. RESULT: Our study revealed that KTRs exhibit significant heterogeneity with COVID-19-induced ARDS compared with those of other individuals, with significant reductions in T cells, as well as an abnormal proliferation of B cells and monocytes. In the context of dual influences from immunosuppression and viral infection, KTRs exhibited more specific plasma cells, along with significant enrichment of dysfunctional GZMB and XAF1 double-positive effector T cells and IFI27-positive monocytes. Additionally, robust communication existed among T cells and monocytes in cytokine signaling. These effects impede the process of immune reconstitution in KTR patients. CONCLUSION: Our findings suggest that KTRs with COVID-19-induced ARDS show elevated antibody levels, impaired T cell differentiation, and dysregulation of innate immunity. In summary, this study provides a theoretical foundation for a comprehensive understanding of COVID-19-induced ARDS in KTRs.

Genetic, Clinical, and Pathologic Backgrounds of Children With X-Linked Alport Syndrome in China: A Monocenter Study.

Background. Characteristics of X-linked Alport syndrome (XLAS) in a cohort of Chinese children. Methods. This work is a retrospective study covering the clinical information, pathological data, and gene sequencing results of 32 cases with XLAS from 2011 to 2022. Results. Among these 32 patients, the youngest age of onset was 3 months. Renal biopsy was performed on 29 children. The lamellated glomerular basement membrane was observed in 19 children using electron microscopy (65.5%). Of the 26 samples tested, 73.1% were found to be negative for collagen-a5 under immunohistochemical staining, showing clinical significance. Next-generation sequencing (NGS) detected 27 pathogenic gene mutations. A total of 15.4% of patients carried de novo mutations. Conclusions. The boys with XLAS showed more typical pathological performance than the girls. Patients with severe mutation were more likely to have proteinuria and hearing impairment. Renal pathology combined with NSG is an important means of diagnosis of AS.

Identification of cuproptosis-related biomarkers and analysis of immune infiltration in allograft lung ischemia-reperfusion injury.

Background: Allograft lung ischemia-reperfusion injury (ALIRI) is a major cause of early primary graft dysfunction and poor long-term survival after lung transplantation (LTx); however, its pathogenesis has not been fully elucidated. Cell death is a mechanism underlying ALIRI. Cuproptosis is a recently discovered form of programmed cell death. To date, no studies have been conducted on the mechanisms by which cuproptosis-related genes (CRGs) regulate ALIRI. Therefore, we explored the potential biomarkers related to cuproptosis to provide new insights into the treatment of ALIRI. Materials and methods: Datasets containing pre- and post-LTx lung biopsy samples and CRGs were obtained from the GEO database and previous studies. We identified differentially expressed CRGs (DE-CRGs) and performed functional analyses. Biomarker genes were selected using three machine learning algorithms. The ROC curve and logistic regression model (LRM) of these biomarkers were constructed. CIBERSORT was used to calculate the number of infiltrating immune cells pre- and post-LTx, and the correlation between these biomarkers and immune cells was analyzed. A competing endogenous RNA network was constructed using these biomarkers. Finally, the biomarkers were verified in a validation set and a rat LTx model using qRT-PCR and Western blotting. Results: Fifteen DE-CRGs were identified. GO analysis revealed that DE-CRGs were significantly enriched in the mitochondrial acetyl-CoA biosynthetic process from pyruvate, protein lipoylation, the tricarboxylic acid (TCA) cycle, and copper-transporting ATPase activity. KEGG enrichment analysis showed that the DE-CRGs were mainly enriched in metabolic pathways, carbon metabolism, and the TCA cycle. NFE2L2, NLRP3, LIPT1, and MTF1 were identified as potential biomarker genes. The AUC of the ROC curve for each biomarker was greater than 0.8, and the LRM provided an excellent classifier with an AUC of 0.96. These biomarkers were validated in another dataset and a rat LTx model, which exhibited good performance. In the CIBERSORT analysis, differentially expressed immune cells were identified, and the biomarkers were associated with the immune cells. Conclusion: NFE2L2, NLRP3, LIPT1, and MTF1 may serve as predictors of cuproptosis and play an important role in the pathogenesis of cuproptosis in ALIRI.

Elastohydrodynamic propulsion of a filament magnetically driven at both ends.

The elastohydrodynamic interaction between an elastic filament and its surrounding fluid was exploited to develop the first microswimmers. These flexible microswimmers are typically actuated magnetically at one end and their propulsion behavior is relatively well understood. In this work, we move beyond the traditional single-end actuation setup and explore the propulsion characteristics of an elastic filament driven by magnetic torques at both ends. We report the emergence of new modes of propulsion behaviors in different physical regimes, depending on the balance of elastic and viscous forces as well as the arrangement of the magnetic moments at the filament ends. In particular, under the same magnetic actuation, a filament driven at both ends can propel either forward or backward depending on its relative stiffness. Moreover, this new backward propulsion mode can generate a magnitude of propulsion that is unattainable by the traditional single-end actuation setup. We characterize these new propulsion behaviors and provide some physical insights into how they emerge from the complex interplay between viscous and elastic forces and magnetic actuation in various configurations. Taken together, these findings could guide the development of soft microrobots with enhanced propulsion performance and maneuverability for future biomedical applications.