Mobile recognition and positioning for multiple visible light communication cells using a convolutional neural network: publisher's note.

This publisher's note contains a correction to Opt. Lett.48, 6468 (2024)10.1364/OL.503007.

RIS-aided dynamically adaptive wide field-of-view receiver for visible light communication in industrial internet of things.

In the current visible light communication (VLC) system, a condenser lens is generally used in the front of receiver to achieve a higher data rate, making an extremely narrow field-of-view for the receiver. With the spread of Industrial Internet of Things (IIoT), the communication between mobile terminals is urgently required. A wide-range detecting method for VLC system in IIoT scenario is asked. In this paper, a novel self-adaptive wide-FoV receiver involving reconfigurable intelligent surfaces (RIS) is proposed. The effective detecting range of the receiver can be expanded by dynamically adjusting the incident light directions with the assistance of RIS. Based on the maximum arrived flux criterion, the mathematical model is established and the optimized RIS parameter tuning algorithm is presented. The feasibility and validity of the method are verified by simulation. The results show that the tolerable transceiver offset can be increased to 2∼4 times as the conventional receiver.

Mobile recognition and positioning for multiple visible light communication cells using a convolutional neural network.

The industrial Internet of Things (IIoT) environment involves multiple production items, such as robots and automated guided vehicles (AGVs), among others. The practical industrial scenario requires communication of production items while also considering mobile recognition and positioning. Hence the perception approach requires not only combining communications but also realizing the recognition and positioning of multiple communication cells. This Letter proposes a multi-optical cell recognition and positioning framework based on LED image features. The LED images are obtained by a CMOS image sensor. This framework utilizes convolutional neural networks (CNN) to train LED images for recognition between multiple optical cells and locates precise positions through region recognition within the optical cells. The experimental results show that the mean accuracy of the CNN model for two LED cells is above 99%, and the mean accuracy of region recognition within the optical cell is as high as 100%, which is significantly better than other traditional recognition algorithms. Therefore, the proposed framework can provide location-aware services for visible light communication and has a wide application prospect in IIoT.

Highly Activated Neuronal Firings Monitored by Implantable Microelectrode Array in the Paraventricular Thalamus of Insomnia Rats.

Insomnia is a common sleep disorder around the world, which is harmful to people's health, daily life, and work. The paraventricular thalamus (PVT) plays an essential role in the sleep-wake transition. However, high temporal-spatial resolution microdevice technology is lacking for accurate detection and regulation of deep brain nuclei. The means for analyzing sleep-wake mechanisms and treating sleep disorders are limited. To detect the relationship between the PVT and insomnia, we designed and fabricated a special microelectrode array (MEA) to record electrophysiological signals of the PVT for insomnia and control rats. Platinum nanoparticles (PtNPs) were modified onto an MEA, which caused the impedance to decrease and improved the signal-to-noise ratio. We established the model of insomnia in rats and analyzed and compared the neural signals in detail before and after insomnia. In insomnia, the spike firing rate was increased from 5.48 ± 0.28 spike/s to 7.39 ± 0.65 spike/s, and the power of local field potential (LFP) decreased in the delta frequency band and increased in the beta frequency band. Furthermore, the synchronicity between PVT neurons declined, and burst-like firing was observed. Our study found neurons of the PVT were more activated in the insomnia state than in the control state. It also provided an effective MEA to detect the deep brain signals at the cellular level, which conformed with macroscopical LFP and insomnia symptoms. These results laid the foundation for studying PVT and the sleep-wake mechanism and were also helpful for treating sleep disorders.

In Vivo Optogenetic Modulation with Simultaneous Neural Detection Using Microelectrode Array Integrated with Optical Fiber.

The detection of neuroelectrophysiology while performing optogenetic modulation can provide more reliable and useful information for neural research. In this study, an optical fiber and a microelectrode array were integrated through hot-melt adhesive bonding, which combined optogenetics and electrophysiological detection technology to achieve neuromodulation and neuronal activity recording. We carried out the experiments on the activation and electrophysiological detection of infected neurons at the depth range of 900-1250 µm in the brain which covers hippocampal CA1 and a part of the upper cortical area, analyzed a possible local inhibition circuit by combining opotogenetic modulation and electrophysiological characteristics and explored the effects of different optical patterns and light powers on the neuromodulation. It was found that optogenetics, combined with neural recording technology, could provide more information and ideas for neural circuit recognition. In this study, the optical stimulation with low frequency and large duty cycle induces more intense neuronal activity and larger light power induced more action potentials of neurons within a certain power range (1.032 mW-1.584 mW). The present study provided an efficient method for the detection and modulation of neurons in vivo and an effective tool to study neural circuit in the brain.

Loop-mediated isothermal amplification (LAMP): A novel rapid detection platform for pathogens.

Foodborne bacterial infections and diseases have been considered to be a major threat for public health in the worldwide. Increased incidence of human diseases caused by foodborne pathogens have been correlated with growing world population and mobility. Loop-mediated isothermal amplification (LAMP) has been regarded as an innovative gene amplification technology and emerged as an alternative to PCR-based methodologies in both clinical laboratory and food safety testing. Nowadays, LAMP has been applied to detection and identification on pathogens from microbial diseases, as it showed significant advantage in high sensitivity, specificity and rapidity. The high sensitivity of LAMP enables detection of the pathogens in sample materials even without time consuming sample preparation. An overview of LAMP mainly containing the development history, reaction principle and its application to four kind of foodborne pathogens detection are presented in this paper. As concluded, with the advantages of rapidity, simplicity, sensitivity, specificity and robustness, LAMP is capable of applications for clinical diagnosis as well as surveillance of infection diseases. Moreover, the main purpose of this paper is to provide theoretical basis for the clinical application of LAMP technology.

Injectable, self-healing hyaluronic acid-based hydrogels for spinal cord injury repair.

The cystic cavity that develops following spinal cord injury is a major obstacle for repairing spinal cord injury (SCI). The injectable self-healing biomaterials treatment is a promising strategy to enhance tissue repair after traumatic spinal cord injury. Herein, a natural extracellular matrix (ECM) biopolymer hyaluronic acid-based hydrogel was developed based on multiple dynamic covalent bonds. The hydrogels exhibited excellent injectable and self-healing properties, could be effectively injected into the injury site, and filled the lesion cavity to accelerate the tissue repair of traumatic SCI. Moreover, the hydrogels were compatible with cells and various tissues and possessed proper stiffness matched with nervous tissue. Additionally, when implanted into the injured spinal cord site, the hyaluronic acid-based hydrogel promoted axonal regeneration and functional recovery by accelerating remyelination, axon regeneration, and angiogenesis. Overall, the injectable self-healing hyaluronic acid-based hydrogels are ideal biomaterials for treating traumatic SCI.

Natural Polysaccharide Film-Based Triboelectric Sensor for Fruit Transportation Collision Monitoring.

Transportation-induced damage to fresh produce is a big challenge in logistics. Current acceleration and pressure sensors for collision monitoring face issues of power dependency, high cost, and environmental concerns. Here, a self-powered and environmentally friendly triboelectric sensor has been developed to monitor fruit collisions in transportation packaging. Microcrystalline cellulose/chitosan and sodium alginate films were prepared as positive and negative tribo-layers to assemble a natural polysaccharide film-based triboelectric nanogenerator (NP-TENG). The NP-TENG's electrical output was proportional to the structure parameters (contact surface roughness and separation gap of the tribo-layers) and the vibration factors (force and frequency) and exhibited excellent stability and durability (over 100,000 cycles under 13 N at 10 Hz). The high mechanical-to-electrical conversion efficiency (instantaneous areal power density of 9.6 mW/m2) and force sensitivity (2.2 V/N) enabled the NP-TENG to be a potential sensor for monitoring fresh produce collisions in packaging during logistics. Transportation simulation measurements of kiwifruits verified that the sensor's electrical outputs increased with the vibration frequency and stacking layer while varying at different packaging locations. This study suggests that the NP-TENG can effectively monitor collision damage during fruit transportation, providing new insights into developing intelligent food packaging systems to reduce postharvest supply chain losses.

Community Incidence Estimates of Five Pathogens Based on Foodborne Diseases Active Surveillance - China, 2023.

What is already known about this topic?: Foodborne diseases, representing significant food safety and public health challenges globally, are not well-documented in terms of incidence, particularly for cases characterized by acute gastroenteritis (AGI) in China. What is added by this report?: This study developed a pyramid model to estimate the incidence of five pathogens, stratified by gender and age. The estimated incidences per 100,000 people with 95% uncertainty intervals (UI) are as follows: Norovirus, 3,188.28 (95% UI: 2,518.03, 7,296.96); Salmonella spp., 1,295.59 (95% UI: 1,002.62, 1,573.11); diarrheagenic E. coli (DEC), 782.62 (95% UI: 651.19, 932.05); Vibrio parahaemolyticus, 404.06 (95% UI: 342.19, 468.93); and Shigella spp., 26.73 (95% UI: 21.05, 33.46). What are the implications for public health practice?: This study elucidates the incidence rates across various gender and age groups, thereby identifying priority populations for targeted preventive interventions aimed at reducing disease burden. These insights are crucial for the development of public health policies and management of food safety risks.

Borneol serves as an adjuvant agent to promote the cellular uptake of curcumin for enhancing its photodynamic fungicidal efficacy against Candida albicans.

Candida albicans (C. albicans), a major opportunistic pathogenic fungus, is known to cause superficial skin infections. Unfortunately, the misuse of antibiotics has led to the emergence of drug resistance in fungi. Antimicrobial photodynamic therapy (aPDT), a non-antibiotic alternative, has shown potential in treating drug-resistant fungal infections. Curcumin is a photodynamically active phytochemical whose photodynamic fungicidal efficacy is largely dependent on its intracellular accumulation. However, curcumin faces challenges in penetrating the cytoplasm due to its poor water solubility and the fungal cell wall. Borneol, another monoterpenoid phytochemical, is known for its ability to enhance drug absorption. In this study, we showed that borneol improved the cellular uptake of curcumin, thereby enhancing its photodynamic fungicidal efficacy against C. albicans. This effect was attributed to borneol's ability to increase cell permeability. Transcriptomic analysis further confirmed that borneol disrupted the normal structure and function of the C. albicans cell wall and membrane, resulting in dysregulated mRNA expression of related genes and ultimately increased cell permeability. As a result, the excessive accumulation of curcumin in C. albicans triggered the overproduction of intracellular ROS upon exposure to blue light. These excessive intracellular ROS disrupted various cellular structures, interfered with essential cellular processes, inhibited biofilm formation and reduced virulence. Remarkably, borneol was also found to enhance curcumin uptake by C. albicans within biofilms, further enhancing the anti-biofilm efficacy of curcumin-mediated aPDT (Cur-aPDT). In conclusion, the results of this study strongly support the potential of borneol as an adjuvant agent to Cur-aPDT in treating superficial cutaneous fungal infections.

Proteomic analysis of tomato (Lycopersicum esculentum var. cerasifarm) expressing the HBsAg gene by 2-dimensional difference gel electrophoresis.

In a previous study, an HBsAg gene-bearing transgenic tomato line was made available and it exhibited notable physiological alterations compared with the non-transgenic tomato (control). In particular, leaves of the transgenic plants were fleshy and dark. We hypothesized that a change in leaf proteins of the transgenic plants account for the observed phenotypes. In this study, total protein content in leaves of the transgenic plants was analyzed by 2-dimensional difference gel electrophoresis. A total number of 700 protein spots were detected on silver-stained gels, of which 368 protein spots were matched between the control and sample gels. Among these matched proteins, the expression levels of 122 proteins in the transgenic plants were upregulated while those of the rest were downregulated. In addition, 25 abundant proteins (value ratio > 2.0) on silver-stained gels were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Sixteen differentially expressed proteins were identified, of which 13 were predicted to be involved in cell division, energy metabolism, protein synthesis and processing. The possible roles of these proteins in the transgenic tomato strain have been discussed. Taken together, our data indicate that significant alterations in protein expression occur in transgenic tomatoes bearing the HBsAg gene. Our findings will help broaden our knowledge of the mechanism by which exogenously expressed genes lead to phenotypic alterations in transgenic plants.

Flexible dual-functionalized hyaluronic acid hydrogel adhesives formed in situ for rapid hemostasis.

Hydrogel adhesives integrating both rapid and strong adhesion to blooding tissues and biocompatibility are highly desired for fast hemostasis. Herein, a flexible hyaluronic acid hydrogel adhesive is fabricated via photocrosslinking of the solution originating from dopamine-conjugated maleic hyaluronic acid (DMHA) in situ. The introduction of acrylate groups with high substitutions into the hydrogel matrix endows the adhesive with rapid gelation and strong tissue adhesion properties through photopolymerization. Moreover, the high substitution of catechol groups with unoxidized state can not only induce red blood cell aggregation and platelets adhesion but also adhere to wound tissue to further enhance hemostasis. Based on its bio-adhesion and procoagulant activity, the DMHA hydrogel formed in situ reveals superior hemostatic performance in the rat liver injury model and noncompressible hemorrhage model, and rabbit femoral artery puncture model, compared to commercial products (gauze, absorbable gelatin sponge) and oxidized DMHA (SMHA) hydrogel. Besides, the hydrogel exhibited good adaptability, biodegradability, and superior cytocompatibility as well as negligible inflammation. This hydrogel adhesive is a promising biological adhesive for hemorrhage control.

A Microelectrode Array Modified by PtNPs/PB Nanocomposites Used for the Detection and Analysis of Glucose-Sensitive Neurons under Different Blood Glucose States.

Hypoglycemia state damages the organism, and glucose-excited and glucose-inhibited neurons from the ventral medial hypothalamus can regulate this state. Therefore, it is crucial to understand the functional mechanism between blood glucose and electrophysiology of glucose-excited and glucose-inhibited neurons. To better detect and analyze this mechanism, a PtNPs/PB nanomaterials modified 32-channel microelectrode array with low impedance (21.91 ± 6.80 kΩ), slight phase delay (-12.7° ± 2.7°), high double layer capacitance (0.606 µF), and biocompatibility was developed to realize in vivo real-time detection of the electrophysiology activities of glucose-excited and glucose-inhibited neurons. The phase-locking level of some glucose-inhibited neurons elevated during fasting (low blood glucose state) and showed theta rhythms after glucose injection (high blood glucose state). With an independent oscillating ability, glucose-inhibited neurons can provide an essential indicator to prevent severe hypoglycemia. The results reveal a mechanism for glucose-sensitive neurons to respond to blood glucose. Some glucose-inhibited neurons can integrate glucose information input and convert it into theta oscillating or phase lock output. It helps in enhancing the interaction between neurons and glucose. Therefore, the research can provide a basis for further controlling blood glucose by modulating the characteristics of neuronal electrophysiology. This helps reduce the damage of organisms under energy-limiting conditions, such as prolonged manned spaceflight or metabolic disorders.

PtNPs/rGO-GluOx/mPD Directionally Electroplated Dual-Mode Microelectrode Arrays for Detecting the Synergistic Relationship between the Cortex and Hippocampus of Epileptic Rats.

Precise and directional couplings of functional nanomaterials with implantable microelectrode arrays (IMEAs) are critical for the manufacture of sensitive enzyme-based electrochemical neural sensors. However, there is a gap between the microscale of IMEA and conventional bioconjugation techniques for enzyme immobilization, which leads to a series of challenges such as limited sensitivity, signal crosstalk, and high detection voltage. Here, we developed a novel method using carboxylated graphene oxide (cGO) to directionally couple the glutamate oxidase (GluOx) biomolecules onto the neural microelectrode to monitor glutamate concentration and electrophysiology in the cortex and hippocampus of epileptic rats under RuBi-GABA modulation. The resulting glutamate IMEA exhibited good performance involving less signal crosstalk between microelectrodes, lower reaction potential (0.1 V), and higher linear sensitivity (141.00 ± 5.66 nA µM-1 mm-2). The excellent linearity ranged from 0.3 to 68 µM (R = 0.992), and the limit of detection was 0.3 µM. For epileptic rats, the proposed IMEA sensitively obtained synergetic variations in the action potential (Spike), local field potentials (LFPs), and glutamate of the cortex and hippocampus during seizure and RuBi-GABA inhibition. We found that the increase in glutamate preceded the burst of electrophysiological signals. At the same time, both changes in the hippocampus preceded the cortex. This reminded us that glutamate changes in the hippocampus could serve as important indicators for early warning of epilepsy. Our findings provided a new technical strategy for directionally stabilizing enzymes onto the IMEA with versatile implications for various biomolecules' modification and facilitated the development of detecting tools for understanding the neural mechanism.

Recent advances and research progress on microsystems and bioeffects of terahertz neuromodulation.

Terahertz waves can interact with the nervous system of organisms under certain conditions. Compared to common optical modulation methods, terahertz waves have the advantages of low photon energy and low risk; therefore, the use of terahertz waves to regulate the nervous system is a promising new method of neuromodulation. However, most of the research has focused on the use of terahertz technology for biodetection, while relatively little research has been carried out on the biological effects of terahertz radiation on the nervous system, and there are almost no review papers on this topic. In the present article, we begin by reviewing principles and objects of research regarding the biological effects of terahertz radiation and summarizing the current state of related research from a variety of aspects, including the bioeffects of terahertz radiation on neurons in vivo and in vitro, novel regulation and detection methods with terahertz radiation devices and neural microelectrode arrays, and theoretical simulations of neural information encoding and decoding. In addition, we discuss the main problems and their possible causes and give some recommendations on possible future breakthroughs. This paper will provide insight and assistance to researchers in the fields of neuroscience, terahertz technology and biomedicine.

Impaired Spatial Firing Representations of Neurons in the Medial Entorhinal Cortex of the Epileptic Rat Using Microelectrode Arrays.

Epilepsy severely impairs the cognitive behavior of patients. It remains unclear whether epilepsy-induced cognitive impairment is associated with neuronal activities in the medial entorhinal cortex (MEC), a region known for its involvement in spatial cognition. To explore this neural mechanism, we recorded the spikes and local field potentials from MEC neurons in lithium-pilocarpine-induced epileptic rats using self-designed microelectrode arrays. Through the open field test, we identified spatial cells exhibiting spatially selective firing properties and assessed their spatial representations in relation to the progression of epilepsy. Meanwhile, we analyzed theta oscillations and theta modulation in both excitatory and inhibitory neurons. Furthermore, we used a novel object recognition test to evaluate changes in spatial cognitive ability of epileptic rats. After the epilepsy modeling, the spatial tuning of various types of spatial cells had suffered a rapid and pronounced damage during the latent period (1 to 5 d). Subsequently, the firing characteristics and theta oscillations were impaired. In the chronic period (>10 d), the performance in the novel object experiment deteriorated. In conclusion, our study demonstrates the detrimental effect on spatial representations and electrophysiological properties of MEC neurons in the epileptic latency, suggesting the potential use of these changes as a "functional biomarker" for predicting cognitive impairment caused by epilepsy.

PtNPs/PEDOT:PSS-Modified Microelectrode Arrays for Detection of the Discharge of Head Direction Cells in the Retrosplenial Cortex of Rats under Dissociation between Visual and Vestibular Inputs.

The electrophysiological activities of head direction (HD) cells under visual and vestibular input dissociation are important to understanding the formation of the sense of direction in animals. In this paper, we fabricated a PtNPs/PEDOT:PSS-modified MEA to detect changes in the discharge of HD cells under dissociated sensory conditions. The electrode shape was customized for the retrosplenial cortex (RSC) and was conducive to the sequential detection of neurons at different depths in vivo when combined with a microdriver. The recording sites of the electrode were modified with PtNPs/PEDOT:PSS to form a three-dimensional convex structure, leading to closer contact with neurons and improving the detection performance and signal-to-noise ratio of the MEA. We designed a rotating cylindrical arena to separate the visual and vestibular information of the rats and detected the changes in the directional tuning of the HD cells in the RSC. The results showed that after visual and vestibular sensory dissociation, HD cells used visual information to establish newly discharged directions which differed from the original direction. However, with the longer time required to process inconsistent sensory information, the function of the HD system gradually degraded. After recovery, the HD cells reverted to their newly established direction rather than the original direction. The research based on our MEAs revealed how HD cells process dissociated sensory information and contributes to the study of the spatial cognitive navigation mechanism.

Detection of neuronal defensive discharge information transmission and characteristics in periaqueductal gray double-subregions using PtNP/PEDOT:PSS modified microelectrode arrays.

Threatened animals respond with appropriate defensive behaviors to survive. It has been accepted that midbrain periaqueductal gray (PAG) plays an essential role in the circuitry system and organizes defensive behavioral responses. However, the role and correlation of different PAG subregions in the expression of different defensive behaviors remain largely unexplored. Here, we designed and manufactured a microelectrode array (MEA) to simultaneously detect the activities of dPAG and vPAG neurons in freely behaving rats. To improve the detection performance of the MEAs, PtNP/PEDOT:PSS nanocomposites were modified onto the MEAs. Subsequently, the predator odor was used to induce the rat's innate fear, and the changes and information transmission in neuronal activities were detected in the dPAG and vPAG. Our results showed that the dPAG and vPAG participated in innate fear, but the activation degree was distinct in different defense behaviors. During flight, neuronal responses were stronger and earlier in the dPAG than the vPAG, while vPAG neurons responded more strongly during freezing. By applying high-performance MEA, it was revealed that neural information spread from the activated dPAG to the weakly activated vPAG. Our research also revealed that dPAG and vPAG neurons exhibited different defensive discharge characteristics, and dPAG neurons participated in the regulation of defense responses with burst-firing patterns. The slow activation and continuous firing of vPAG neurons cooresponded with the regulation of long-term freezing responses. The results demonstrated the important role of PAG neuronal activities in controlling different aspects of defensive behaviors and provided novel insights for investigating defense from the electrophysiological perspective.

Injectable and fast gelling hyaluronate hydrogels with rapid self-healing ability for spinal cord injury repair.

Self-healing natural hydrogels still suffer from some issues such as unfit stiffness, poor healing efficiency, and lack of biocompatibility and hydrolytic stability, although they have been used to treat spinal cord injury (SCI). Herein, we develop the injectable, self-healing hyaluronate hydrogels based on multiple dynamic covalent bonds. The hydrogels exhibit fast gelation and excellent self-healing capability as well as injectability, favoring in situ formation for the hydrogels in target sites and maintaining their structural stability. Furthermore, the hydrogels are compatible with neural stem cells and various tissues and possess proper stiffness similar to nervous tissue. Interestingly, the hydrogel can induce neural differentiation of neural stem cells. In vivo experiment further illustrates that the hydrogels promote angiogenesis and remyelination as well as neuron regeneration, leading to the significant locomotor recovery of the SCI model rats. This injectable self-healing hyaluronic acid-based hydrogel is a potential candidate for nerve repair.

Multiple Crosslinking Hyaluronic Acid Hydrogels with Improved Strength and 3D Printability.

Hyaluronic acid (HA) hydrogel is preferred for biomedicine applications, as it possesses biodegradability, biocompatibility, and cell-regulated capacity as well as high hydration nature similar to the native extracellular matrix. However, HA hydrogel fabricated via a 3D printing technique often faces poor printing properties. In this study, maleiated sodium hyaluronate (MHA) with a high substituted degree of the acrylate group (i.e., 2.27) and thiolated sodium hyaluronate (SHHA) were synthesized. By blending these modified HAs, the MHA/SHHA hydrogels were prepared via pre-crosslinking through thiol-acrylate Michael addition and subsequently covalent crosslinking using thiol-acrylate and acrylate-acrylate photopolymerization mechanisms. Rheological properties, swelling behaviors, and mechanical properties can be modulated by altering the molar ratio of the thiol group and acrylate group. The results showed that the MHA/SHHA hydrogel precursors have rapidly gelling capacity and improved compressive strength. Based on these results, high-resolution hydrogel scaffolds with good structural stability were prepared by extrusion-based 3D printing. This HA hydrogel is cytocompatible and capable of supporting adherence of L929 cells, indicating its great potential for tissue engineering scaffolds.