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Sleep plays a role in maintaining our physical well-being. However, sleep-related issues impact millions of people globally. Accurate monitoring of sleep is vital for identifying and addressing these problems. While traditional methods like polysomnography (PSG) are commonly used in settings, they may not fully capture natural sleep patterns at home. Moreover, PSG equipment can disrupt sleep quality. In recent years, there has been growing interest in the use of sensors for sleep monitoring. These lightweight sensors can be easily integrated into textiles or wearable devices using technology. The flexible sensors can be designed for skin contact to offer continuous monitoring without being obtrusive in a home environment. This review presents an overview of the advancements made in flexible sensors for tracking body movements during sleep, which focus on their principles, mechanisms, and strategies for improved flexibility, practical applications, and future trends.

Abstract It is challenging to match the mutual interactions between implant and host because the biomaterials usually cannot actively adjust their performance to the changing microenvironment. Surface potential is one of the critical factors affecting the bioactivity of biomaterials, but it is difficult to be directly controlled in vivo. Magnetic stimulation has attracted much attention due to its deep penetrability, good reliability, and convenient operability. Here, titanium dioxide (TiO2) nanotubes and Terfenol‐D/P(VDF‐TrFE) composite film are prepared by anodic oxidation and solution casting methods on opposite sides of a titanium sheet, respectively. Terfenol‐D magnetostrictive microparticles deform under a magnetic field, generating surface potential on the P(VDF‐TrFE) piezoelectric matrix through magneto‐electric coupling. Correspondingly, equal opposite charges are induced on the surface of TiO2 nanotubes. Stem cells cultured on TiO2 nanotubes show that cell adhesion, proliferation, and differentiation abilities can be regulated by magnetic strength, which correlates with the absorption of charged proteins. Therefore, a cascade coupling of magnetic, mechanical, electric, biochemical, and cellular effects is established. This work demonstrates the feasibility of regulating the bioactivity of biomaterials in vivo through a magnetic field.

Abstract Objectives This study aimed to (1) examine the cross-sectional and longitudinal relationships between depressive symptoms and health services utilization among Chinese middle-aged and older adults; and (2) evaluate whether there exists a rural–urban difference in such relationships. Methods Data was obtained from China Health and Retirement Longitudinal Study (CHARLS) in 2013 and 2015, a nationally representative survey of 13,551 adults aged 45 years and above in China. Results Depressive symptoms were positively associated with a greater likelihood of outpatient and inpatient health services utilization. This association was consistent across rural and urban settings, indicating the robustness of such findings across geographic areas. Conclusions Findings indicate that depressive symptoms are significantly associated with both in-patient and out-patient health service utilization among Chinese adults. Screening for depressive symptoms needs to be incorporated in these care settings in China.

Abstract Background Ewing sarcoma, the second most frequent bone tumor in children and adolescents, is often presented with localized disease or metastatic-related symptoms. In this study, we aim to construct and validate a nomogram for patients with Ewing sarcoma to predict the 3- and 5-year overall survival (OS) based on the Surveillance, Epidemiology, and End Results (SEER) database. Methods Demographic and clinic pathological characteristics of patients with Ewing sarcoma diagnosed between 2010 and 2015 were extracted from SEER database. Univariate and multivariate Cox analyses were carried out to identify the independent characteristics. The independent factors were further included into the construction of a nomogram. Finally, c-index and calibration curves were used to validate the nomogram. Results A total of 578 patients were enrolled into our analysis. The results of univariate Cox analysis showed that age, 7th AJCC stage, 7th AJCC T stage, 7th AJCC N stage, 7th AJCC M stage, metastatic status to lung, liver and bone were significant factors. Multivariate Cox analysis was performed and it confirmed age, N stage and bone metastasis as independent variables. Next, a nomogram was constructed using these independent variables in prediction to the 3- and 5-year OS. Furthermore, favorable results with c-indexes (0.757 in training set and 0.697 in validation set) and calibration curves closer to ideal curves indicated the accurate predictive ability of this nomogram. Conclusions The individualized nomogram demonstrated a good ability in prognostic prediction for patients with Ewing sarcoma.

BackgroundRenal cancer (RC) is one of the most common malignant tumors of the urinary system, and molecular targets for the specific diagnosis and treatment of RC have been widely explored. The purpose of this study was to systematically analyze circular RNAs (circRNAs), which may serve as novel tumor markers in terms of the diagnosis, prognosis and clinicopathological characteristics of RC.MethodsPubMed and Web of Science were systematically searched for literature as up to July 30, 2021. All included studies were evaluated by the evaluation system, and the results were satisfactory. Hazard ratios (HRs) and odds ratios (ORs) were used to assess the association of circRNAs with diagnostic and clinicopathological indicators. The sensitivity (SEN), specificity (SPE), positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and area under the summary receiver operating characteristic curve (AUC) were combined to evaluate the diagnostic performance of circRNAs in RC.ResultsWe included 22 studies that met the criteria, including 18 that were prognostic, 4 that were diagnostic, and 12 that were clinicopathologically relevant. In terms of prognosis, we found that upregulated circRNAs were positively associated with poor overall survival in patients with RC (HR=1.63, 95% CI=1.43–1.85). In terms of diagnosis, the combined SEN, SPE and AUC of circRNAs in the diagnosis of RC were 0.82, 0.84 and 0.89 (0.86–0.91), respectively. In terms of clinicopathological features, upregulated circRNAs were associated with the Fuhrman grade (OR=0.641, 95% CI=0.471–0.873), T stage (OR=0.236, 95% CI=0.141–0.396), TNM stage (OR=0.225, 95% CI=0.158–0.321) and lymphatic metastasis (OR=0.329, 95% CI=0.193–0.560).ConclusionOur meta-analysis confirms that circRNAs may be candidate biomarkers for the diagnosis, prognosis, and clinicopathological indicators of RC.

Abstract Conductive polymers (CPs) are generally insoluble, and developing hydrophilic CPs is significant to broaden the applications of CPs. In this work, a mussel-inspired strategy was proposed to construct hydrophilic CP nanoparticles (CP NPs), while endowing the CP NPs with redox activity and biocompatibility. This is a universal strategy applicable for a series of CPs, including polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene). The catechol/quinone contained sulfonated lignin (LS) was doped into various CPs to form CP/LS NPs with hydrophilicity, conductivity, and redox activity. These CP/LS NPs were used as versatile nanofillers to prepare the conductive hydrogels with long-term adhesiveness. The CP/LS NPs-incorporated hydrogels have a good conductivity because of the uniform distribution of the hydrophilic NPs in the hydrogel network, forming a well-connected electric path. The hydrogel exhibits long-term adhesiveness, which is attributed to the mussel-inspired dynamic redox balance of catechol/quinone groups on the CP/LS NPs. This conductive and adhesive hydrogel shows good electroactivity and biocompatibility and therefore has broad applications in electrostimulation of tissue regeneration and implantable bioelectronics.

Data aggregation is a fundamental and efficient algorithm to reduce the communication overhead and energy consumption in wireless sensor networks (WSNs). However, WSNs need both energy-efficient and privacy-preserving when being deployed in an unprotected area. In this paper, we propose an energy-efficient and privacy-preserving data aggregation algorithm CBDA (the chain-based data aggregation). In the CBDA, sensor nodes will be organized as a tree topology. The leaf nodes of the tree sequentially reconnect with each other to form many chain topologies. For assuring data privacy, after data gathering, (1) the tail nodes (the nodes which on the tail of chain) need to slice their sensing data into J fragments. One fragment is kept by themselves, and they distribute the J -1 data fragments to their neighbor nodes. (2) Each tail node will inject some fake fragments into its J -1 fragments to interfere with adversaries. The CBDA can achieve less energy consumption and higher aggregation accuracy during data aggregation. We perform a comprehensive simulation to make a comparison among the CBDA with existing algorithms. The experimental results demonstrate that the CBDA outperforms the existing algorithms.

Biomimetic catechol-based adhesives have attracted significant interest but can lose adhesion due to excessive oxidation. Here, the authors report on the addition of silver-Lignin nanoparticles as a dynamic catechol redox system to maintain catechol/quinone balance, making a reusable, antibacterial bioadhesive.

Delay-division-multiplexing (DDM) involves the use of signal preprocessing for the detection of data via sub-Nyquist analog-to-digital sampling, based on preallocated relative sampling delays among optical network users (ONUs) in an orthogonal frequency-division multiplexing (OFDM) passive optical network (PON). If a DDM-PON consists of M virtual groups, the sampling rate at the receivers is only 1/M of the Nyquist rate, but the maximum capacity of each ONU is fixed at 1/M of the total capacity. In this study, we developed a novel DDM scheme that uses hybrid sub-Nyquist sampling rates to accommodate heterogeneous services of different capacities in an OFDM-PON. To equalize the transmission performances using hybrid sub-Nyquist sampling rates, the modification of preprocessing was proposed, and its necessity was demonstrated. Without loss of generality, we experimentally demonstrated a 25-Gbps DDM-OFDM-PON using hybrid sampling at 1/2, 1/8, and 1/32 (or 1/8, 1/16, and 1/32) of the Nyquist rate. Compared to a DDM-PON with a fixed subNyquist rate, the received signals based on hybrid sub-Nyquist sampling rates show similar sensitivities. A loss budget of 26 dB was experimentally achieved using all sub-Nyquist sampling rates after employing the modified preprocessing.

Access management of IoT devices is extremely important, and a secure login authentication scheme can effectively protect users’ privacy. However, traditional authentication schemes are threatened by shoulder-surfing attacks, and biometric-based schemes, such as fingerprint recognition and face recognition, that are commonly used today can also be cracked. Researchers have proposed some schemes for current attacks, but they are limited by usability. For example, the login authentication process requires additional device support. This method solves the problem of attacks, but it is unusable, which limits its application. At present, most authentication schemes for the Internet of Things and mobile platforms either focus on security, thus ignoring availability, or have excellent convenience but insufficient security. This is a symmetry problem worth exploring. Therefore, users need a new type of login authentication scheme that can balance security and usability to protect users’ private data or maintain device security. In this paper, we propose a login authentication scheme named PinWheel, which combines a textual password, a graphical password, and biometrics to prevent both shoulder-surfing attacks and smudge attacks and solves the current schemes’ lack of usability. We implemented PinWheel and evaluated it from the perspective of security and usability. The experiments required 262 days, and 573 subjects participated in our investigation. The evaluation results show that PinWheel can at least effectively resist both mainstream attacks and is superior to most existing schemes in terms of usability.

With the development of information technology, films, music, and other publications are inclined to be distributed in digitalized form. However, the low cost of data replication and dissemination leads to digital rights problems and brings huge economic losses. Up to now, existing digital rights management (DRM) schemes have been powerless to deter attempts of infringing digital rights and recover losses of copyright holders. This paper presents a YODA-based digital watermark management system (Y-DWMS), adopting non-repudiation of smart contract and blockchain, to implement a DRM mechanism to infinitely amplify the cost of infringement and recover losses copyright holders suffered once the infringement is reported. We adopt game analysis to prove that in Y-DWMS, the decision of non-infringement always dominates rational users, so as to fundamentally eradicate the infringement of digital rights, which current mainstream DRM schemes cannot reach.

A smart watch is a kind of emerging wearable device in the Internet of Things. The security and privacy problems are the main obstacles that hinder the wide deployment of smart watches. Existing security mechanisms do not achieve a balance between the privacy-preserving and data access control. In this paper, we propose a fine-grained privacy-preserving access control architecture for smart watches (FPAS). In FPAS, we leverage the identity-based authentication scheme to protect the devices from malicious connection and policy-based access control for data privacy preservation. The core policy of FPAS is two-fold: (1) utilizing a homomorphic and re-encrypted scheme to ensure that the ciphertext information can be correctly calculated; (2) dividing the data requester by different attributes to avoid unauthorized access. We present a concrete scheme based on the above prototype and analyze the security of the FPAS. The performance and evaluation demonstrate that the FPAS scheme is efficient, practical, and extensible.

Traditional methods using coupling chemistry for surface grafting of heparin onto polyurethane (PU) are disadvantageous due to their generally low efficiency. In order to overcome this problem, a quick one-step photografting method is proposed here. Three heparin derivatives incorporating 0.21, 0.58, and 0.88 wt% pendant aryl azide groups were immobilized onto PU surfaces, leading to similar grafting densities of 1.07, 1.17, and 1.13 μg/cm2, respectively, yet with increasing densities of anchoring points. The most negatively charged surface and the maximum binding ability towards antithrombin III were found for the heparinized PU with the lowest amount of aryl azide/anchor sites. Furthermore, decreasing the density of anchoring points was found to inhibit platelet adhesion to a larger extent and to prolong plasma recalcification time, prothrombin time, thrombin time, and activated partial thromboplastin time to a larger extent. This was also found to enhance the bioactivity of immobilized heparin from 22.9% for raw heparin to 36.9%. This could be explained by the enhanced molecular mobility of immobilized heparin when it is more loosely anchored to the PU surface, as well as a higher surface charge.

IoT devices are now enriching people’s life. However, the security of IoT devices seldom attracts manufacturers’ attention. There are already some solutions to the problem of connecting a smart device to a user’s wireless network based on the 802.11 transmission such as Smart Config from TI. However, it is insecure in many situations, and it does not have a satisfactory transmission speed, which does not mean that it has a low bit rate. It usually takes a long time for the device to recognize the data it receives and decode them. In this paper, we propose a new Wi-Fi connection method based on audio waves. This method is based on MFSK (Multiple frequency-shift keying) and works well in short distance, which enables the correctness and efficiency. In addition, audio waves can hardly be eavesdropped, which provides higher security than other methods. We also put forward an encryption solution by using jamming signal, which can greatly improve the security of the transmission.