Search

Background and objective Tumor microenvironment (TME) is one of the important factors in tumorigenesis and progression, in which tumor-associated macrophages (TAMs) play an important role in non-small cell lung cancer (NSCLC) progression. However, the mechanism of TAMs in NSCLC progression remains unclear, so this study aimed to investigate the role of TAMs in NSCLC progression and to find potential therapeutic targets. Methods Gene Expression Profiling Interactive Analysis (GEPIA) database was used to analyze the expression of prostaglandin E2 receptor 4 (EP4) mRNA in NSCLC and normal lung tissues; the protein expression levels of cyclooxygenase-2 (COX-2), EP4, cluster of differentiation 86 (CD86), CD163 and CD31 were detected by immunohistochemistry (IHC) in 120 NSCLC tissues and 24 paracancerous tissues specimens. The nude mouse lung adenocarcinoma cell A549 and macrophage RAW264.7 co-transplanted tumor model was established. And the samples were collected by gavage with EP4 inhibitor E7046, and then stained with hematoxylin-eosin (HE), IHC, and immunofluorescence (IF), and then detected by Western blot for the epithelial mesenchymal transformation (EMT) of the tumor tissues of the nude mice in each group. Western blot was used to detect the expressions of EMT related protiens in each group of nude mice; full-length transcriptome sequencing was used to screen the key genes causing liver metastasis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was performed. Results EP4 mRNA expression level in NSCLC tissues was generally lower than that in normal lung tissues (P0.05); the main pathways enriched in the differential genes of the full-length transcriptome were the PI3K-AKT and MAPK signaling pathways. Conclusion During NSCLC development, the COX-2/PGE2/EP4 axis may promote tumor progression by inducing macrophage functional activation, and EP4 may be a potential new target for tumor immunotherapy. This study provides new perspectives and ideas for in-depth exploration of the mechanisms of NSCLC development, as well as a theoretical basis for the development of new therapeutic strategies for NSCLC.

The success of an organism depends on the molecular and ecological adaptations that promote its beneficial fitness. Parasitoids are valuable biocontrol agents for successfully managing agricultural pests, and they have evolved diversified strategies to adapt to both the physiological condition of hosts and the competition of other parasitoids. Here, we deconstructed the parasitic strategies in a highly successful parasitoid, Trichopria drosophilae, which parasitizes a broad range of Drosophila hosts, including the globally invasive species D. suzukii. We found that T. drosophilae had developed specialized venom proteins that arrest host development to obtain more nutrients via secreting tissue inhibitors of metalloproteinases (TIMPs), as well as a unique type of cell—teratocytes—that digest host tissues for feeding by releasing trypsin proteins. In addition to the molecular adaptations that optimize nutritional uptake, this pupal parasitoid has evolved ecologically adaptive strategies including the conditional tolerance of intraspecific competition to enhance parasitic success in older hosts and the obligate avoidance of interspecific competition with larval parasitoids. Our study not only demystifies how parasitoids weaponize themselves to colonize formidable hosts but also provided empirical evidence of the intricate coordination between the molecular and ecological adaptations that drive evolutionary success.

Abstract Background Mesothelin (MSLN) has been implicated in cancer migration, invasion, and prognosis, making it a potential tumor marker. However, the precise role of MSLN in the migration and invasion of malignant pleural mesothelioma (MPM) remains elusive, and effective noninvasive methods for assessing MSLN status are currently lacking. In this study, we focused on MSLN expression and elucidated the underlying mechanisms by which MSLN regulates migration and invasion in MPM. Building upon this knowledge, we developed an MRI nanoprobe that targets MSLN to assess its status in vitro and in vivo by comparing T2 signal intensity and T2 values on magnetic resonance imaging examinations. This nanoprobe combines the anatomical information obtained from MRI with biological information obtained from MSLN for comprehensive evaluation of MPM. Results Notably, we observed that MSLN expression in the epithelial type of MPM was higher and increased continuously with tumor growth than that in other types. In addition, MSLN upregulation promoted N-cadherin, matrix metalloproteinase-7, and MMP9 expression and resulted in higher migration/invasion ability and shorter survival. We synthesized MSLN-targeted nanoprobes (Fe3O4@SiO2-PEG-MSLN, FSPM) to assess MSLN expression by comparing the T2 signal intensity and T2 value of different cell lines and mice after 14, 28, and 42 days of modeling. Remarkably, MSLN-targeted nanoprobes demonstrated excellent targeting capabilities. In vitro studies revealed a pronounced reduction in T2 signal intensity and T2 values of the epithelial type as the probe concentration increased. In addition, in vivo experiments demonstrated a gradual decline in these parameters over time, particularly in the epithelial type as compared to the biphasic type, corresponding to the dynamic expression patterns of MSLN during different growth stages. Conclusion Our comprehensive research succeeded in confirming the regulatory mechanisms by which MSLN influences migration and invasion. Moreover, we introduced a promising method for monitoring MSLN expression that may help in facilitating the early detection, histological subtype identification, and assessment of migration, invasion, and prognosis in MPM.

Background and objective Currently, a significant number of miners are involved in mining operations at the Gejiu tin mine in Yunnan. This occupational setting is associated with exposure to dust particles, heavy metals, polycyclic aromatic hydrocarbons, and radioactive radon, thereby significantly elevating the risk of lung cancer. This study aims to investigate the involvement of leptin-mediated extracellular regulated protein kinase (ERK) signaling pathway in the malignant transformation of rat alveolar type II epithelial cells induced by Yunnan tin mine dust. Methods Immortalized rat alveolar cells type II (RLE-6TN) cells were infected with Yunnan tin mine dust at a concentration of 200 μg/mL for nine consecutive generations to establish the infected cell model, which was named R200 cells. The cells were cultured normally, named as R cells. The expression of leptin receptor in both cell groups was detected using the Western blot method. The optimal concentration of leptin and mitogen-activated protein kinase kinase (MEK) inhibitor (U0126) on R200 cells was determined using the MTT method. Starting from the 20th generation, the cells in the R group were co-cultured with leptin, while the cells in the R200 group were co-cultured with the MEK inhibitor U0126. The morphological alterations of the cells in each group were visualized utilizing hematoxylin-eosin staining. Additionally, concanavalin A (ConA) was utilized to detect any morphological differences, and an anchorage-independent growth assay was conducted to assess the malignant transformation of the cells. The changes in the ERK signaling pathway in epithelial cells after the action of leptin were detected using the Western blot method. Results Both the cells in the R group and R200 group express leptin receptor OB-R. Compared to the R200 group, the concentration of leptin at 100 ng/mL shows the most significant pro-proliferation effect. The proliferation of R200 cells infected with the virus is inhibited by 30 μmol/L U0126, and a statistically significant divergence was seen when compared to the control group (P

Abstract Background In this study, we aimed to perform a comprehensive analysis on the metagenomic next-generation sequencing for the etiological diagnosis of septic patients, and further to establish optimal read values for detecting common pathogens. Methods In this single-center retrospective study, septic patients who underwent pathogen detection by both microbial culture and metagenomic next-generation sequencing in the intensive care unit of the Second People’s Hospital of Shenzhen from June 24, 2015, to October 20, 2019, were included. Results A total of 193 patients with 305 detected specimens were included in the final analysis. The results of metagenomic next-generation sequencing showed significantly higher positive rates in samples from disparate loci, including blood, bronchoalveolar lavage fluid, and cerebrospinal fluid, as well as in the determination of various pathogens. The optimal diagnostic reads were 2893, 1825.5, and 892.5 for Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae, respectively. Conclusions The metagenomic next-generation sequencing is capable of identifying multiple pathogens in specimens from septic patients, and shows significantly higher positive rates than culture-based diagnostics. The optimal diagnostic reads for frequently detected microbes might be useful for the clinical application of metagenomic next-generation sequencing in terms of timely and accurately determining etiological pathogens for suspected and confirmed cases of sepsis due to well-performed data interpretation.

Evolutionary arms races can drive adaptations in hosts and parasites as well as among competing parasites. A combination of multi-omics and functional tests identifies a set of genes that allow a parasitic wasp to minimize intraspecific competition by inducing hosts to escape before more wasps can parasitize them.

Parasitism is a widespread evolutionary strategy. A study that spans functional and evolutionary genomics identifies the molecular basis and history underlying two genes that have mediated divergent parasitic strategies (specialist vs generalist) between two sister species of parasitoid wasp.

Background Oxidative stress (OS) is key to various diseases and is implicated in cancer progression and oncogenesis. However, the potential diagnostic value of OS-related genes in skin cutaneous melanoma (SKCM) remains unclear. Methods We used data of RNA sequencing from 471 tumor tissues and one healthy tissue acquired from The Cancer Genome Atlas (TCGA)-SKCM cohort. The Genome Tissue Expression database was used to acquire transcriptome data from 812 healthy samples. OS-related genes that were differentially expressed between SKCM and healthy samples were investigated and 16 prognosis-associated OS genes were identified. The prognostic risk model was built using univariate and Cox multivariate regressions. The prognostic value of the hub genes was validated in the GSE65904 cohort, which included 214 SKCM patients. Results The overall survival rate of SKCM patients in the high-risk group was decreased compared to the low-risk group. In both TCGA and GSE65904 cohorts, the ROC curves suggested that our prognostic risk model was more accurate than other clinicopathological characteristics to diagnose SKCM. Moreover, risk score and nomograms associated with the expression of hub genes were developed. These presented reiterated our prognostic risk model. Altogether, this study provides novel insights with regards to the pathogenesis of SKCM. The 16 hub genes identified may help in SKCM prognosis and individualized clinical treatment.

Natural small-molecule phenols (NSMPs) share some bioactivities. The anxiolytic activity of NSMPs is attracting attention in the scientific community. This paper provides data supporting the hypothesis that NSMPs are generally anxiolytic. The anxiolytic activities of seven simple phenols, including phloroglucinol, eugenol, protocatechuic aldehyde, vanillin, thymol, ferulic acid, and caffeic acid, were assayed with the elevated plus maze (EPM) test in mice. The oral doses were 5, 10 and 20 mg/kg, except for phloroglucinol for which the doses were 2.5, 5 and 10 mg/kg. All tested phenols had anxiolytic activity in mice. The phenolic hydroxyl group in 4-hydroxycinnamic acid (4-OH CA) was essential for the anxiolytic activity in the EPM test in mice and rats compared to 4-chlorocinnamic acid (4-Cl CA). The in vivo spike recording of rats’ hippocampal neurons also showed significant differences between 4-OH CA and 4-Cl CA. Behavioral and neuronal spike recording results converged to indicate the hippocampal CA1 region might be a part of the anxiolytic pathways of 4-OH CA. Therefore, our study provides further experimental data supporting NSMPs sharing anxiolytic activity, which may have general implications for phytotherapy because small phenols occur extensively in herbal medicines.

Abstract The origin of energetic charged particles in universe remains an unresolved issue. Astronomical observations combined with simulations have provided insights into particle acceleration mechanisms, including magnetic reconnection acceleration, shock acceleration, and stochastic acceleration. Recent experiments have also confirmed that electrons can be accelerated through processes such as magnetic reconnection and collisionless shock formation. However, laboratory identifying stochastic acceleration as a feasible mechanism is still a challenge, particularly in the creation of collision-free turbulent plasmas. Here, we present experimental results demonstrating kinetic turbulence with a typical spectrum k −2.9 originating from Weibel instability. Energetic electrons exhibiting a power-law distribution are clearly observed. Simulations further reveal that thermal electrons undergo stochastic acceleration through collisions with multiple magnetic islands-like structures within the turbulent region. This study sheds light on a critical transition period during supernova explosion, where kinetic turbulences originating from Weibel instability emerge prior to collisionless shock formation. Our results suggest that electrons undergo stochastic acceleration during this transition phase.

The spectra and global distributions of the X-ray emissions generated by the solar wind charge-exchange (SWCX) process in the terrestrial magnetosheath are investigated based on a global hybrid model and a global geocoronal hydrogen model. Solar wind O6+ ions, which are the primary charge state for oxygen ions in solar wind, are considered. The line emissivity of the charge-exchange-borne O5+ ions is calculated by the Spectral Analysis System for Astrophysical and Laboratory (SASAL). It is found that the emission lines from O5+ range from 105.607 to 118.291 eV with a strong line at 107.047 eV. We then simulate the magnetosheath X-ray emission intensity distributions with a virtual camera at two positions of the north pole and dusk at six stages during the passing of a perpendicular interplanetary shock combined with a tangential discontinuity structure through the Earth’s magnetosphere. During this process, the X-ray emission intensity increases with time, and the maximum value is 27.11 keV cm−2 s−1 sr−1 on the dayside, which is 4.5 times that before the solar wind structure reached the Earth. A clear shock structure can be seen in the magnetosheath and moves earthward. The maximum emission intensity seen at dusk is always higher than that seen at the north pole.

In present paper, a delayed SEIR model of malware propagation on mobile wireless sensor networks is formulated. Basic reproduction number of the model is calculated by employing the next generation matrix method and impact of the time delay due to incubation period of malware is discussed with the help of eigenvalue method. What is more, properties of the Hopf bifurcation are derived by using center manifold method. To minimize number of the infectious nodes and the cost related with detoxication, an optimal control strategy is presented by constructing a suitable Hamiltonian function. Numerical calculations are performed to justify the obtained theoretical findings.

With the development of information technology, individuals are able to receive rumor information through various channels and subsequently act based on their own perceptions. The significance of the disparity between media and individual cognition in the propagation of rumors cannot be underestimated. In this paper, we establish a dual-layer rumor propagation model considering the differences in individual cognition to study the propagation behavior of rumors in multiple channels. Firstly, we obtain the threshold for rumor disappearance or persistence by solving the equilibrium points and their stability. The threshold is related to the number of media outlets and the number of rumor debunkers. Moreover, we have innovatively designed a class of non-periodic intermittent noise stabilization methods to suppress rumor propagation. This method can effectively control rumor propagation based on a flexible control scheme, and we provide specific expressions for the control intensity. Finally, we have validated the accuracy of the theoretical proofs through experimental simulations.

This paper formulates a Susceptible–Latent–Breaking out–Patched–Susceptible (SLBPS) virus propagation model with delay of temporary immunity. The influence of time delay on stability of the model is examined by analyzing the distribution of eigenvalues of the characteristic equation. Furthermore, we also demonstrate the direction and stability of the Hopf bifurcation. Lastly, optimal control strategies in terms of the rate at which susceptible, latent, break out nodes acquiring patches to improve performance of the model are presented. For the sake of the correctness of the theoretical analysis, some numerical simulations are also presented.

Founded on bounded rationality and limited information, evolutionary game theory has been preliminarily applied in many fields, such as electricity market (EM). To address the complex behavioral decision-making issues in the more-common three-population multi-strategy evolutionary game (3PmSEG) scenarios in EM. This paper explores the long-term evolutionarily stable equilibrium (ESE) characteristics of general 3PmSEG systems with the aim of systematically investigating the evolution process of long-term on-grid bidding of a generation-side EM based on these features. First, the long-term ESE characteristics of general three-population two-strategy and three-strategy evolutionary games are thoroughly investigated. Complete relative net payoff (RNP) parameters are defined for these games. Then, the modeling idea of general 3PmSEGs is elaborated. Research shows that the game can be guided to evolve toward an expected long-term ESE point by properly adjusting its RNP parameters. To verify this, finally, the long-term on-grid bidding of power generation is investigated for a tripartite generation-side EM. The case study reveals that effective government supervision can effectively promote new energy accommodation of the market. Overall, the models developed in this paper are relatively universal and practical, which can provide some theoretical and methodological references for complex evolutionary game issues in related fields.

The Zeeman splitting effect is observed in a strong magnetic field generated by a laser-driven coil. The expanding plasma from the coil wire surface is concentrated at the coil center and interacts with the simultaneously generated magnetic field. The Cu I spectral lines at wavelengths of 510.5541, 515.3235, and 521.8202 nm are detected and analyzed. The splittings of spectral lines are used to estimate the magnetic field strength at the coil center as ∼31.4 ± 15.7 T at a laser intensity of ∼5.6 × 1015 W/cm2, which agrees well with measurements using a B-dot probe. Some other plasma parameters of the central plasma disk are also studied. The temperature is evaluated from the Cu I spectral line intensity ratio, while the electron density is estimated from the Stark broadening effect.

The aim of the present study was to determine the effect of a small dose of aspirin on a quantitative test of 24-h urinary protein in patients with hypertension in pregnancy. In total, 224 patients with hypertension in pregnancy were continuously selected and were randomly divided into the control group (50 cases with conventional therapy), aspirin 50 mg/day group (60 cases), aspirin 75 mg/day group (58 cases), and aspirin 100 mg/day group (56 cases). Clinical effects were compared from 16 gestational weeks to childbirth. According to the comparison in the four groups, there was no statistical difference in the mean arterial pressure, pre-eclampsia rate, gestational weeks, and caesarean section rate (p>0.05). The 24-h urinary protein and endothelin-1 (ET-1) level were significantly decreased following treatment, and were less than the control and 50 mg/day groups. The superoxide dismutase (SOD) level was significantly increased, and higher than the control and 50 mg/day groups. In terms of the 75 and 100 mg/day, control and 50 mg/day groups, there was no statistical difference (p>0.05). A comparison of the complication rate in the four groups of fetuses during the perinatal period, no statistical difference was observed (p>0.05). Thus, the results show that, regarding patients with hypertension in pregnancy, 75 mg/day aspirin can decrease the 24-h urinary protein, SOD, and ET-1 level. However, the results remain to be confirmed to improve maternal and infant outcome in delivery. [ABSTRACT FROM AUTHOR]

By introducing a circular Dammann grating (CDG) into the pump unit, we demonstrated an endpumped Nd:YAG laser that emitted a vortex and first-order LG mode with high laser efficiency and high power. In our scheme, the CDG was used to reshape the pumping light into an annular profile, and the adaptation of it was realized easily by inserting it into the pump unit of a conventional end-pumped solid-state laser; the laser cavity was simple, compact, and consisted of only a laser crystal and an output coupler. The beam power of this laser reached 1.86 W at an absorbed pump power of 6.38 W with a slope efficiency of 34.5%. [ABSTRACT FROM AUTHOR]

In this paper, based on backstepping technique and time delay estimation (TDE) technique, an adaptive time delay compensation control scheme is developed for a class of piezoelectric positioning mechanical systems with Bouc-Wen hysteresis and input saturation constraint. The nonlinear part of the Bouc-Wen model is estimated online by TDE, and the TDE error introduced by TDE is compensated online by an adaptive law. Furthermore, an auxiliary variable system is used to deal with the input saturation constraint. Based on the Lyapunov method, the stability of the closed-loop system is analyzed and proved. Two simulation examples are given to demonstrate the effectiveness of the proposed control scheme.

Nasopharyngeal carcinoma (NPC) is endemic in southern China. Due to the unique anatomical and biological properties of NPCs, radiotherapy or combined modality based on radiotherapy is an effective treatment option. Helical tomotherapy (HT) is an emerging intensity modulated radiotherapy technology. The advantages of dose homogeneity, steepness of dose gradient, and protection of normal organs are reflected in the treatment of head and neck cancers. We present the preliminary (2-year) clinical outcomes of HT in 85 patients with locally advanced NPC (LA-NPC). Of these patients, 3 patients (3.5%) experienced treatment interruption due to severe pulmonary infection, and 82 (96.5%) completed radiation treatments. The 2-year estimate of progression-free survival, local relapse-free survival, nodal relapse-free survival, distant metastases-free survival, and overall survival rate were 90%, 96.3%, 98.8%, 96.3%, and 96.3%, respectively. Among the three patients that died, one had stage III disease and died from fatal nasopharyngeal bleeding after radiotherapy, while the other two patients succumbed to local recurrence. Our experience suggests that HT can achieve promising disease control and survival in the treatment of LA-NPC patients with mild acute and late toxicity profiles.

The intelligent manufacturing of power systems has led to many challenges. The cyber-physical system (CPS) was introduced to solve the problem of insufficient integration of equipment and systems. It brings advantages, but also risks. In the distribution network CPS, malicious attacks on the PC-PLC communication network can cause significant incidents and affect system safety. The paper discusses two challenges, of possible mutated virus attacks and multi-delay in the PC-PLC coupled network. We present for the first time a virus-mutation and multi-delay propagation model. Then, to effectively control the virus propagation in the network and minimize the cost, the paper proposes five control measures, introduces their possible control combinations, and solves the optimal control problem with the Pontryagin maximum theorem. Finally, simulations verify the optimal control strategies for all combinations. By comparing the effects of maximum control, minimum control, average control, and optimal control, the optimal control strategy has been proven to be effective.

In wireless rechargeable sensors (WRSNs), the system is vulnerable to be attacked by malware. Because of the distributed network structure of WRSNs, the malware attack has great influence on the security system of WRSNs. With the variability in malware, the problem of decryption and coding errors will lead to the malware mutating. In this paper, there are two problems to be solved, including the malware mutation and the charging delay in WRSNs. The malware mutation state and the low-energy state are introduced. Firstly, three different equilibrium solutions of the mutation model are given. Then, the local stability is proven by the characteristic equation, and the system will be stabilized at different equilibrium solutions when the base reproductive number is different. With the condition of charging delay, the bifurcation phenomenon is investigated by using the Hopf bifurcation theory. Furthermore, to improve the security of WRSNs and decrease the control cost, the Pontryagin’s Maximum principle is applied to obtain an optimal control scheme under mutation and charging delay. Finally, the numerical simulation is applied by Matlab to confirm this model. The simulation results show that the mutation malware can be controlled when the delay is less than the maximum threshold.

The risk of ship–bridge collisions should be evaluated using advanced models to consider different anti-collision and bridge-protection measures. This study aimed to propose a method to evaluate the effectiveness of active and passive safety measures in preventing ship–bridge collision. A novel ship–bridge collision probability formulation taking into consideration different safety measures was proposed. The model was applied at Jintang Bridge in China where the surrounding vessel traffic is ultra-crowded. We calculated the collision probability between the bridge and passing traffic using automatic identification system (AIS) data, Monte Carlo simulation, and Bayesian networks. Results under four different safety measures (i.e., active measures, passive measures, both measures and none) were analyzed and compared. The analysis concluded that both active and passive safety measures are effective in reducing the ship–bridge collision probability. Active measures, if deployed properly, can provide protection at an equivalent level than passive measures against collision risks. However, passive measures, such as setting arresting cables, are necessary in cases where the response time of the active measures is long. The proposed method and the results obtained from the case study may be useful for robust and systematic effectiveness evaluation of safety measures in other cases worldwide.

As wireless rechargeable sensor networks (WRSNs) are gradually being widely accepted and recognized, the security issues of WRSNs have also become the focus of research discussion. In the existing WRSNs research, few people introduced the idea of pulse charging. Taking into account the utilization rate of nodes’ energy, this paper proposes a novel pulse infectious disease model (SIALS-P), which is composed of susceptible, infected, anti-malware and low-energy susceptible states under pulse charging, to deal with the security issues of WRSNs. In each periodic pulse point, some parts of low energy states (LS nodes, LI nodes) will be converted into the normal energy states (S nodes, I nodes) to control the number of susceptible nodes and infected nodes. This paper first analyzes the local stability of the SIALS-P model by Floquet theory. Then, a suitable comparison system is given by comparing theorem to analyze the stability of malware-free T-period solution and the persistence of malware transmission. Additionally, the optimal control of the proposed model is analyzed. Finally, the comparative simulation analysis regarding the proposed model, the non-charging model and the continuous charging model is given, and the effects of parameters on the basic reproduction number of the three models are shown. Meanwhile, the sensitivity of each parameter and the optimal control theory is further verified.

With the rapid development of international trade and the fast growth of port freight volumes, the risk of ship pollution in marine areas has significantly increased. Frequent ship pollution accidents seriously endanger marine ecosystems and are extremely unfavorable to economic development and marine environmental protection. In this study, we investigate the results of emergency responses after ship pollution accidents and analyze the factors affecting a successful emergency response. A Bayesian network model of the emergency response results of ship pollution is established, and the emergency response results of ship pollution accidents in the example of Zhoushan Port are analyzed. Based on the analysis, suggestions for strengthening the emergency preparedness of Zhoushan Port are proposed. We believe that the results of this are beneficial for improving ship pollution risk management and decision making, and that they have practical significance for marine environmental protection.

In this paper, we study the achievable spectral efficiency (SE) for multi-user massive multipleinput multiple-output (MIMO) systems in a single cell, where the base station (BS) has the perfect channel state information and utilizes the maximum ratio transmission precoding. The channel model is built based on a finite dimensional mmWave channel by taking the azimuth angle into account and all users are assumed to have a random distribution in a circular-shaped cell. When the BS is deployed with a full uniform linear array (ULA) configuration, an analytical expression is derived by taking into account the expectation of the squared inner product between every two channel vectors that is viewed as inter-user interference. To effective suppress inter-user interference, we focus on studying the BS installing a multiple sub-arrays antenna configuration, in which all antennas are divided into three sub-ULA configurations to cover three regions of the cell, respectively. A closed-form expression on the inter-user interference is derived. Furthermore, we evaluate the performance of full ULA and three sub-ULA configurations and derive approximated expressions on the achievable SE. Numerical results reveal that the achievable SE of system increases with the number of antennas, while it approaches saturation in the high-SNR regime. Interestingly, it is also found that three sub-ULA configurations are able to suppressive user interference and their achievable SE is superior to full ULA configuration, which has a great potential of mmWave massive MIMO systems.

As energy-harvesting wireless sensor networks (EHWSNs) are increasingly integrated with all walks of life, their security problems have gradually become hot issues. As an attack means, malicious programs often attack sensor nodes in critical locations in the networks to cause paralysis and information leakage of the networks, resulting in security risks. Based on the previous works and the introduction of solar charging, we proposed a novel model, namely, Susceptible-Infected-Low (energy)-Recovered-Dead (SILRD) with solar energy harvesters. Meanwhile, this paper takes Logistic Growth as the drop rate of sensor nodes and the infection rate of multitype malicious programs under nonlinear condition into consideration. Finally, an Λ-Susceptible-Infected-Low (energy)-Recovered-Dead (ΛSILRD) model is proposed. Based on the Pontryagin Maximum Principle, this paper proposes the optimal strategies based on the SILRD with solar energy harvesters and the ΛSILRD. The effectiveness of SILRD with solar energy harvesters was demonstrated by comparison with the general epidemic model. At the same time, by analyzing different charging strategies, we conclude that solar charging is highly efficient. Moreover, we further analyze the influence of controllable and uncontrollable input and various node degrees on ΛSILRD model.

In this paper, we propose a novel heterogeneous model to describe the propagation dynamics of malware (viruses, worms, Trojan horses, etc.) in wireless sensor networks. Our model takes into consideration different battery-level sensor nodes contrary to existing models. In order to control the spread of malware, we design an aperiodically intermittent controller driven by white noise, which has striking advantages of lower cost and more flexible control strategy. We give a distinct condition on stability in probability one using graph-theoretical Lyapunov function and stochastic analysis method. Our results show that the nonlinear malware propagation system can be stabilized by intermittent stochastic perturbation under the intermittent time related to stochastic perturbation intensity. Our theoretical results can be applied to understand the observed mechanisms of malware and design interventions to control the spread of malware. Numerical simulations illustrate our analytical results clearly.

Based on the traditional propagation model, this paper innovatively divides nodes into high- and low-energy states through introducing Low-energy (L) state and presents a whole new propagation model which is more suitable for WSNs (wireless sensor networks) against malicious programs, namely, SILRD (Susceptible, Infected, Low-energy, Recovered, Dead) model. In this paper, nodes are divided into five states according to the residual energy and infection level, and the differential equations are constructed to describe the evolution of nodes. At the same time, aiming at the exhaustion of WSNs’ energy, this paper introduces charging as a method to supplement the energy. Furthermore, we regard the confrontation between WSNs and malicious programs as a kind of game and find the optimal strategies by using the Pontryagin Maximum Principle. It is found that charging as a defense mechanism can inhibit the spread of malicious programs and reduce overall costs. Meanwhile, the superiority of bang-bang control on the SILRD model is highlighted by comparing with square control.