Bioinspired Stimuli-Responsive Materials for Soft Actuators.

Biological species can walk, swim, fly, jump, and climb with fast response speeds and motion complexity. These remarkable functions are accomplished by means of soft actuation organisms, which are commonly composed of muscle tissue systems. To achieve the creation of their biomimetic artificial counterparts, various biomimetic stimuli-responsive materials have been synthesized and developed in recent decades. They can respond to various external stimuli in the form of structural or morphological transformations by actively or passively converting input energy into mechanical energy. They are the core element of soft actuators for typical smart devices like soft robots, artificial muscles, intelligent sensors and nanogenerators. Significant progress has been made in the development of bioinspired stimuli-responsive materials. However, these materials have not been comprehensively summarized with specific actuation mechanisms in the literature. In this review, we will discuss recent advances in biomimetic stimuli-responsive materials that are instrumental for soft actuators. Firstly, different stimuli-responsive principles for soft actuators are discussed, including fluidic, electrical, thermal, magnetic, light, and chemical stimuli. We further summarize the state-of-the-art stimuli-responsive materials for soft actuators and explore the advantages and disadvantages of using electroactive polymers, magnetic soft composites, photo-thermal responsive polymers, shape memory alloys and other responsive soft materials. Finally, we provide a critical outlook on the field of stimuli-responsive soft actuators and emphasize the challenges in the process of their implementation to various industries.

Causal association between kynurenine and depression investigated using two-sample mendelian randomization.

As research progresses, the intricate metabolic connections between depression and tryptophan, as well as kynurenine (KYN), have become increasingly evident. In studies investigating the relationship between KYN and depression, the conclusions reached thus far have been inconsistent. Therefore, we propose employing a two-sample mendelian randomization (MR) approach to further elucidate the relationship between KYN and depression. We utilized extensive data from large-scale genome-wide association studies to identify single nucleotide polymorphisms that act as instrumental variables for kynurenine and depression in European ancestry populations, ensuring compliance with MR assumptions. We employed five MR algorithms, namely, weighted median, MR-Egger, inverse variance weighted (IVW), simple mode, and weighted mode, with IVW as the primary analysis method. Sensitivity tests were conducted using Cochran's Q test, MR-Egger intercept test, MR Pleiotropy Residual Sum and Outlier, and Leave-one-out analysis.The IVW analysis revealed that each standard deviation increase in kynurenine corresponded to a 1.4-fold increase in the risk of depression (OR = 1.351, 95% CI 1.110-1.645, P = 0.003). The direction of the effect size (positive or negative) was consistent with the findings from the other four algorithms. Sensitivity tests indicated no heterogeneity or horizontal pleiotropy among the instrumental variables. Elevated levels of kynurenine have a causal relationship with an increased risk of developing depression.

Characterization and treatment of oily sludge: A systematic review.

Oily sludge is a prevalent hazardous waste generated in the petroleum industry, and effectively treating it remains a key challenge for the petroleum and petrochemical sectors. This paper provides an introduction to the origin, properties, and hazards of oil sludge while summarizing various treatment methods focused on reduction, recycling, and harmlessness. These methods include combustion, stabilization/solidification, oxidation and biodegradation techniques, solvent extraction, centrifugation, surfactant-enhanced oil recovery processes as well as freezing-thawing procedures. Additionally discussed are pyrolysis, microwave radiation applications along with electrokinetic method utilization for oily sludge treatment. Furthermore explored are ultrasonic radiation techniques and froth flotation approaches. These technologies have been thoroughly examined through discussions that analyze their process principles while considering influencing factors as well as advantages and disadvantages associated with each method. Based on the characteristics of oily sludge properties and treatment requirements, a selection methodology for choosing appropriate oily sludge treatment technology is proposed in this study. The development direction of processing technology has also been explored to provide guidance aimed at improving efficiency by optimizing existing processing technologies. The paper presents a comprehensive treatment method for oily sludge, ensuring that all the parameters meet the standard requirements.

High-Linearity Flexible Pressure Sensor Based on the Gaussian-Curve-Shaped Microstructure for Human Physiological Signal Monitoring.

Flexible pressure sensors with high-performance show broad application prospects in health monitoring, wearable electronic devices, intelligent robot sensing, and other fields. Although flexible pressure sensors have made significant progress in sensitivity and detection range, most of them still exhibit strong nonlinearity, which leads to significant troubles in signal acquisition and thus limits their popularity in practical applications. It remains a serious challenge for the flexible pressure sensor to achieve high linearity while maintaining high sensitivity. Herein, a doped sensing membrane with a uniformly distributed Gaussian-curve-shaped micropattern array was developed using the micro-electromechanical systems (MEMS) process, and a flexible sensor structure with the doped film as the core was designed and constructed. The prototype sensor has a high sensitivity of 1.77 kPa-1 and a linearity of 0.99 in the full detection range of 20 Pa to 30 kPa. In addition, its excellent performance also includes fast response/recovery times (∼25/50 ms) and long-term endurance (>10,000 cycles at 15 kPa). The prototype sensor has been successfully demonstrated in human pulse monitoring, speech recognition, and gesture recognition. The 2 × 6 sensor array can detect the spatial pressure distribution. Thus, such a microstructure shape design will open a new way to fabricate a high-linearity pressure sensor for potential applications in health monitoring, human-machine interaction, etc.

One-step fabrication of high-performance graphene composites from graphite solution for bio-scaffolds and flexible strain sensors.

Graphene composites possess great application potential in various fields including flexible electrodes, wearable sensors and biomedical devices owing to their excellent mechanical and electrical properties. However, it remains challenging to fabricate graphene composites-based devices with high consistency due to the gradual aggression effect of graphene during fabrication process. Herein, we propose a method for one-step fabricating graphene/polymer composite-based devices from graphite/polymer solution by using electrohydrodynamic (EHD) printing with the Weissenberg effect (EPWE). Taylor-Couette flows with high shearing speed were generated to exfoliate high-quality graphene with a rotating steel microneedle coaxially set in a spinneret tube. The effects of the rotating speed of the needle, spinneret size and precursor ingredients on the graphene concentration were discussed. As a proof of concept, EPWE was used to successfully fabricate graphene/polycaprolactone (PCL) bio-scaffolds with good biocompatibility and graphene/thermoplastic polyurethane strain sensor for detecting human motions with a maximum gauge factor more than 2400 from 40% to 50% strain. As such, this method sheds a new light on one-stepin situfabrication of graphene/polymer composite-based devices from graphite solution with low cost.

Peony-Glycyrrhiza Decoction for Antipsychotic-Related Hyperprolactinemia in Patients with Schizophrenia: A Randomized Controlled Trial.

Background: Most antipsychotic drugs are dopamine receptor antagonists that usually lead to abnormal increases in prolactin concentrations and the development of hyperprolactinemia (HPRL), which in turn causes sexual dysfunction in patients. Peony-Glycyrrhiza Decoction (PGD) enhanced dopamine D2 receptors (DRD2) and dopamine transporter (DAT) and significantly reversed the expression of DRD2 and DAT. Therefore, we hypothesized that PGD might effectively improve hyperprolactinemia and alleviate sexual dysfunction in patients. Methods: We performed an 8-week randomized controlled study on 62 subjects with schizophrenia who were randomized into two groups. The experimental group was treated with the PGD intervention, and the control group did not receive treatment. The primary outcome indicators were the levels of sex hormones and the total Arizona Sexual Experience Scale (ASEX) score. Results: There was a significant difference in PRL levels between the two groups at weeks 4 and 8. From the beginning to the end of the experiment, there was a significant increase in PRL levels in the control group, while there was no significant change in the experimental group. The ASEX scale assessed sexual function in both groups, and patients in the experimental group showed an improvement in sexual function at week 8. During the experiment, the two groups found no differences between Positive and Negative Syndrome Scale (PANSS) scores and Treatment Emergent Symptom Scale (TESS) scores. Conclusion: PGD significantly improved the patient's sexual function but was less effective in reducing prolactin levels and may prevent further increases in prolactin levels.

A flexible pressure sensor with highly customizable sensitivity and linearity via positive design of microhierarchical structures with a hyperelastic model.

The tactile pressure sensor is of great significance in flexible electronics, but sensitivity customization over the required working range with high linearity still remains a critical challenge. Despite numerous efforts to achieve high sensitivity and a wide working range, most sensitive microstructures tend to be obtained only by inverting naturally existing templates without rational design based on fundamental contact principles or models for piezoresistive pressure sensors. Here, a positive design strategy with a hyperelastic model and a Hertzian contact model for comparison was proposed to develop a flexible pressure sensor with highly customizable linear sensitivity and linearity, in which the microstructure distribution was precalculated according to the desired requirement prior to fabrication. As a proof of concept, three flexible pressure sensors exhibited sensitivities of 0.7, 1.0, and 1.3 kPa- 1 over a linear region of up to 200 kPa, with a low sensitivity error (<5%) and high linearity (~0.99), as expected. Based on the superior electromechanical performance of these sensors, potential applications in physiological signal recognition are demonstrated as well, and such a strategy could shed more light on demand-oriented scenarios, including designable working ranges and linear sensitivity for next-generation wearable devices.

Self-Patterning of Highly Stretchable and Electrically Conductive Liquid Metal Conductors by Direct-Write Super-Hydrophilic Laser-Induced Graphene and Electroless Copper Plating.

Stretchable electrodes are desirable in flexible electronics for the transmission and acquisition of electrical signals, but their fabrication process remains challenging. Herein, we report an approach based on patterned liquid metals (LMs) as stretchable electrodes using a super-hydrophilic laser-induced graphene (SHL-LIG) process with electroless plating copper on a polyimide (PI) film. The LMs/SHL-LIG structures are then transferred from the PI film to an Ecoflex substrate as stretchable electrodes with an ultralow sheet resistance of 3.54 mΩ per square and excellent stretchability up to 480% in elongation. Furthermore, these electrodes show outstanding performances of only 8% electrical resistance changes under a tensile strain of 300%, and strong immunity to temperature and pressure changes. As demonstration examples, these electrodes are integrated with a stretchable strain sensing system and a smart magnetic soft robot toward practical applications.

Research progress in the correlation between SREBP/PCSK9 pathway and lipid metabolism disorders induced by antipsychotics. / SREBP/PCSK9é€šè·¯ä¸ŽæŠ—ç²¾ç¥žç— è¯ç‰©æ‰€è‡´è„‚ä»£è°¢ç´Šä¹±ç›¸å ³æ€§çš„ç ”ç©¶è¿›å±•.

Antipsychotic medications are commonly used to treat schizophrenia, but they can have negative effects on lipid metabolism, leading to an increased risk of cardiovascular diseases, reduced life expectancy, and difficulties with treatment adherence. The specific mechanisms by which antipsychotics disrupt lipid metabolism are not well understood. Sterol regulatory element-binding proteins (SREBPs) are important transcriptional factors that regulate lipid metabolism. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a gene regulated by SREBPs, plays a critical role in controlling levels of low-density lipoprotein cholesterol (LDL-C) and has become a focus of research on lipid-lowering drugs. Recent studies have shown that antipsychotic drugs can affect lipid metabolism through the SREBP/PCSK9 pathway. A deep understanding of the mechanism for this pathway in antipsychotic drug-related metabolic abnormalities will promote the prevention of lipid metabolism disorders in patients with schizophrenia and the development and application of new drugs.

Electroacupuncture improves cognitive impairment in diabetic cognitive dysfunction rats by regulating the mitochondrial autophagy pathway.

BACKGROUND: Diabetes-associated cognitive dysfunction has become a major public health concern. However, the mechanisms driving this disease are elusive. Herein, we explored how electroacupuncture improves learning and memory function in diabetic rats. METHODS: The diabetic model was established by intraperitoneal injection of streptozotocin (STZ) in adult Sprague-Dawley rats. Rats were fed on high-fat and high-sugar diets. Learning and memory functions were assessed using behavioral tests. The hematoxylin and eosin (H&E) staining, Western blotting, real-time PCR, ELISA, immunohistochemistry, and transmission electronic microscopy (TEM) was performed to test related indicators. RESULTS: High-fat and high-sugar diets impaired learning and memory function in rats, while electroacupuncture treatment reversed these changes. The model group presented highly prolonged escape latency compared to the control group, indicating impaired learning and memory functions. The TEM examination showed that electroacupuncture enhanced Aß clearance and mitochondrial autophagy in hippocampal neuronal cells by increasing DISC1 expression. CONCLUSIONS: Electroacupuncture improves learning and memory function in diabetic rats by increasing DISC1 expression to promote mitophagy. This enhanced Aß clearance, alleviating cytotoxicity in hippocampal neuronal cells.

A Thermal-Switchable Metamaterial Absorber Based on the Phase-Change Material of Vanadium Dioxide.

This article presents a thermal-switchable metamaterial absorber (TSMA) based on the phase-change material of vanadium dioxide (VO2). VO2 thin film was deposited on sapphire substrate by magnetron sputtering followed by vacuum annealing treatment. Then, the prepared VO2 film was sliced into tiny chips for thermal-switchable elements. The surface structure of TSMA was realized by loading four VO2 chips into a square metallic loop. The absorption frequency of TSMA was located at 7.3 GHz at room temperature and switched to 6.8 GHz when the temperature was heated above the critical phase transition temperature of VO2. A VO2-based TSMA prototype was fabricated and measured to verify this design. The design is expected to be used in metasurface antennas, sensors, detectors, etc.

Design, fabrication and application of magnetically actuated micro/nanorobots: a review.

Magnetically actuated micro/nanorobots are typical micro- and nanoscale artificial devices with favorable attributes of quick response, remote and contactless control, harmless human-machine interaction and high economic efficiency. Under external magnetic actuation strategies, they are capable of achieving elaborate manipulation and navigation in extreme biomedical environments. This review focuses on state-of-the-art progresses in design strategies, fabrication techniques and applications of magnetically actuated micro/nanorobots. Firstly, recent advances of various robot designs, including helical robots, surface walkers, ciliary robots, scaffold robots and biohybrid robots, are discussed separately. Secondly, the main progresses of common fabrication techniques are respectively introduced, and application achievements on these robots in targeted drug delivery, minimally invasive surgery and cell manipulation are also presented. Finally, a short summary is made, and the current challenges and future work for magnetically actuated micro/nanorobots are discussed.