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In the rapidly evolving landscape of Internet of Things (IoT), Zigbee networks have emerged as a critical component for enabling wireless communication in a variety of applications. Despite their widespread adoption, Zigbee networks face significant security challenges, particularly in key management and network resilience against cyber attacks like distributed denial of service (DDoS). Traditional key rotation strategies often fall short in dynamically adapting to the ever-changing network conditions, leading to vulnerabilities in network security and efficiency. To address these challenges, this paper proposes a novel approach by implementing a reinforcement learning (RL) model for adaptive key rotation in Zigbee networks. We developed and tested this model against traditional periodic, anomaly detection-based, heuristic-based, and static key rotation methods in a simulated Zigbee network environment. Our comprehensive evaluation over a 30-day period focused on key performance metrics such as network efficiency, response to DDoS attacks, network resilience under various simulated attacks, latency, and packet loss in fluctuating traffic conditions. The results indicate that the RL model significantly outperforms traditional methods, demonstrating improved network efficiency, higher intrusion detection rates, faster response times, and superior resource management. The study underscores the potential of using artificial intelligence (AI)-driven, adaptive strategies for enhancing network security in IoT environments, paving the way for more robust and intelligent Zigbee network security solutions. [ABSTRACT FROM AUTHOR]

The self-healing cement used in oil wells aims to provide long-term interlayer isolation by enabling the cement system to repair itself. This paper compared the absorption properties of 2-acrylamido-2-methyl propanesulfonic acid (AMPS)-based superabsorbent polymer (SAP) and acrylic acid (AA)-based SAP in water and cement slurry filtrate. The effect of cement slurry filtrate on the water absorption properties of the two SAPs was evaluated. The results showed that the calcium ions in the cement slurry would crosslink with the carboxyl groups in the AA-SAP, increasing the crosslink density and greatly reducing its absorption rate in water. Compared to AA-SAP, AMPS-SAP is more suitable for oil well cement slurries. AMPS-SAP can help reduce the fluid loss of cement slurry. The addition of 0.4% AMPS-SAP in cement slurry results in a 64 mL decrease in fluid loss. The properties (rheological properties, thickening time, and compressive strength) of cement slurry meet the requirements for well cementing construction. [ABSTRACT FROM AUTHOR]

Purpose: Increased vagal activity plays a prominent role in vasovagal syncope (VVS). The aim of this study was to characterize vagal function in VVS by evaluating the heart rate (HR) deceleration capacity (DC) and the HR deceleration runs (DRs) in patients with VVS between attacks. Methods: A total of 188 consecutive VVS patients were enrolled in the study, of whom 129 had positive head-up tilt test (HUTT); 132 healthy participants were enrolled as controls. DC, DRs (DR2, i.e., episodes of 2 consecutive beat-to-beat HR decelerations), and the sum of DR8-10 (very long DR [VLDR]) were calculated using 24-h electrograms. Clinical characteristics, DC, and DRs were compared among syncope groups and controls. Results: Patients with VVS had higher DC (10.63 ± 2.1 vs. 6.58 ± 1.7 ms; P < 0.001) and lower minimum HR and DR6-10 than controls. No significant differences in DC or DR6-10 were found between the patients with positive and those with negative HUTT results. In multivariate logistic regression analysis, minimum HR ≥ 40 bpm (odds ratio [OR] 0.408, 95% confidence interval [CI] 0.167–0.989; P = 0.048), daytime DC ≥ 7.37 ms (OR 3.040, 95% CI 1.220–7.576; P = 0.013), and VLDR ≥ 0.046% (OR 0.306, 95% CI 0.138–0.679; P = 0.004) were demonstrated to be risk factors significantly associated with VVS. Conclusion: Compared to healthy controls, patients with VVS demonstrated distinct HR deceleration profiles between attacks, including overall higher DC and lower DR6-10. [ABSTRACT FROM AUTHOR]

For a complex operational environment, to actualize safe obstacle avoidance and collision avoidance, a swarm must be capable of autonomous formation reconfiguration. First, this paper introduces the basic pigeon-inspired optimization (PIO) algorithm, and establishes the unmanned aerial vehicle motion model and the virtual leader swarm formation control structure. Then, given the above knowledge, the basic error objective function of a UAV swarm, obstacle avoidance objective function, and collision avoidance objective function are devised based on the variable-stepsize model predictive control technique. Next, the adaptive perception Cauchy mutation PIO algorithm is proposed by introducing the Cauchy mutation operator, adaptive weight factor, and roulette wheel selection into the basic PIO. This algorithm is used to optimally solve the abovementioned swarm objective functions. Ultimately, a set of comparative simulations are performed to verify the effectiveness and reliability of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Cardiac resynchronization therapy (CRT) is an effective treatment for selected patients with systolic heart failure. Unlike conventional biventricular pacing (BIP), the left ventricular multipoint pacing (MPP) can increase the number of left ventricular pacing sites via a quadripolar lead positioned in the coronary sinus. This synthetic study was conducted to integratively and quantitatively evaluate the clinical outcome of MPP in comparison with BIP. We systematically searched the databases of EMBASE, Ovid medline, and Cochrane Library through May 2018 for studies comparing the clinical outcome of MPP with BIP in the patients who accepted CRT. Hospitalization for reason of heart failure, left ventricular eject fraction (LVEF), CRT response, all-cause morbidity, and cardiovascular death rate was collected for meta-analysis. A total of 11 studies with 29,606 participants were included in this meta-analysis. Compared with BIP group, MPP decreased heart failure hospitalization (OR, 0.41; 95% CI, 0.33 to 0.50; P < 0.00001), improved LVEF (mean difference, 4.97; 95% CI, 3.11 to 6.83; P < 0.00001), increased CRT response (OR, 3.64; 95% CI, 1.68 to 7.87; P = 0.001), and decreased all-cause morbidity (OR, 0.41; 95% CI, 0.26-0.66; P = 0.0002) and cardiovascular death rate (OR, 0.21; 95% CI, 0.11-0.40; P < 0.00001). The published literature demonstrates that MPP was more effective than BIP in the heart failure patients who accepted cardiac resynchronization therapy. [ABSTRACT FROM AUTHOR]

Using a photodeformable polymer material, liquid-crystalline polymer incorporated with azobenzene moieties, a spoke-type micromotor is designed, which could convert light energy directly into mechanical work. It consists of four driving belts, whose mechanical model is established and the driving moment of the micromotor upon irradiation with UV light and without photoirradiation is calculated, respectively. According to the calculated driving moment, the UV light and the visible light are arranged to irradiate from parallel and opposite direction of the micromotor simultaneously, which convert the bending deflection of the photodeformable polymer material belts to continuous rotation of the micromotor. As light is a green energy source that can be controlled remotely, instantly and without the aid of electric wires, the photodeformable polymer material has great potential to be utilized in micro-actuator and other relative applications. [ABSTRACT FROM AUTHOR]

Microparticles (MPs) are vesicles released from activated or apoptotic cells. MP derive from various cells, most notably platelets, but also leucocytes, lymphocytes, erythrocytes, and endothelial cells. The aim of this study was to investigate endothelial MP (EMP), platelet MP (PMP), lymphocyte MP and monocyte MP and TF-positive MPs (TF MPs) in patients with coronary heart disease (CHD), and to evaluate the correlation of these MPs with Interleukin-6 (IL-6) and C-reactive protein (CRP). Different cell-derived MPs and TF MPs were analyzed by flow cytometry in 40 patients with myocardial infarction (MI), 30 unstable angina (UA), 20 stable angina (SA) and 20 healthy individuals, and IL-6 and CRP were determined by ELISA and special protein analyzer, respectively. Compared with SA and control, EMP and PMP was significantly elevated in MI and UA ( P < 0.001), and TF MPs was significantly elevated in MI and UA ( P < 0.001). EMP and PMP correlated with IL-6 ( r = 0.822, P < 0.001 and r = 0.567, P < 0.001; respectively) or CRP level ( r = 0.597, P < 0.001 and r = 0.66, P < 0.001; respectively). Different cell-derived MPs in CHD may indicate the different pathophysiological changes in vessels, and MPs may both participate in the development of thrombosis and enhance the vascular inflammation. [ABSTRACT FROM AUTHOR]

Acute coronary syndrome (ACS) is a group of clinical symptoms that results from complete or partial occlusive thrombus, which is caused by coronary an atherosclerotic plaque rupture or erosion. According to a recent study, CD4 CD28 T cells are found in atherosclerotic plaques and the peripheral circulation blood in patients with ACS, these cells play an important role in plaque ruptures. CD4 CD28 T cells are an unusual subset of helper cells, which expand and have harmful effects in ACS. In this review, we discuss the current issues on the generation of CD4 CD28 T cells and focus on their phenotypic and functional characteristics relevant to the development of cardiovascular events. Targeting the CD4 CD28 T cells subset in ACS could provide novel therapeutic means to prevent acute life-threatening coronary events. [ABSTRACT FROM AUTHOR]

Lost circulation controlling & killing material has been a focused issue since a long time ago. A novel leak resistance fluid with the raw materials such as SDS, SDBS, HES, PAM and proprietary productions has been developed from laboratory. The experiment and application shows that the new leak resistance fluid can plug leaking passage of different sizes simultaneously. Observing with 1000 to 2000 time microscope, it is found that the working liquid contains a kind of spherical material which has the microstructure of "one core, two layers, and three membranes". When it is in a static state, the inside of the material looks like an airbag and the outside looks like some fuzzy things which has high gel strength. While when it is in a dynamic state, the fuzzy thing is cut or scattered and flow ability becomes much better. That is the reason why it is called fuzzy-ball. When the diameter or the width of the leak passage is greater than the fuzzy-ball's, the fuzzy-ball accumulates in conical shape to decompose the working fluid pressure of liquid column to achieve blocking; when the diameter or the width of the leak passage is equivalent to the fuzzy-ball's, the fuzzy-ball changes from sphere to oval-shape to increase the resistance to the leak passage and plug the holes; when the diameter or the width of the leak passage is smaller than the fuzzy-ball's, the leaks could be blocked up by the non-permeable membrane formed by the gel of high strength in the working fluid. In these cases, the leak passages of different sizes could be blocked comprehensively. [ABSTRACT FROM AUTHOR]