Enzyme Tunnel Dynamics and Catalytic Mechanism of Norcoclaurine Synthase: Insights from a Combined LiGaMD and DFT Study.

This study conducts a systematic investigation into the catalytic mechanism of norcoclaurine synthase (NCS), a key enzyme in the biosynthesis of tetrahydroisoquinolines (THIQs) with therapeutic applications. By integration of LiGaMD and DFT calculations, the reaction pathway of NCS is mapped, providing detailed insights into its catalytic activity and selectivity. Our findings underscore the critical role of E103 in substrate capture and reveal the hitherto unappreciated influence of nonpolar residues M183 and L76 on tunnel dynamics. A prominent discovery is the identification of a high-energy barrier (44.2 kcal/mol) associated with the aromatic electrophilic attack, which pinpoints the rate-limiting step. Moreover, we disclose the existence of dual transition states leading to different products with the energetically favored six-membered ring formation consistent with experimental evidence. These mechanistic revelations not only refine our understanding of NCS but also advocate for a renewed emphasis on enzyme tunnel engineering for optimizing THIQs biosynthesis. The research sets the stage for translating these findings into practical enzyme modifications. Our results highlight the potential of NCS as a biocatalyst to overcome the limitations of current synthetic methodologies, such as low yields and environmental impacts, and provide a theoretical contribution to the efficient, eco-friendly production of THIQs-based pharmaceuticals.

Experimental study on dynamic elastic modulus loss of concrete broken by high voltage pulse discharge based on orthogonal design.

High pulse discharge breakage has a vast prospect as a fresh crushing mechanism for it has the capability to enhance the comminuting effect, however, the breaking mechanism is not yet well studied. In this orthogonal designed research, 27 indoor tests of high voltage pulse discharge (HVPD) for breaking concrete together with the determination of dynamic elastic modulus of concrete based on three variables, i.e. applied voltage, pulse number, and discharge electrode gap, were carried out at three levels. The effects of these factors were studied by using significance and range analysis. The results showed that among these factors, the pulse number has the greatest impact on the dynamic elastic modulus loss (DEML) of concrete, while the applied voltage has the least influence. By changing the value of pulse number and applied voltage, the DEML can be increased to 12.9% and 26.7%, respectively. The impact of the factors' combination was experimentally proven, and the resulting DEML of concrete broken by HVPD was obtained as 219.73 ± 9.58 MPa, which was 25.19% higher than the maximum of the DEML of concrete broken by HVPD in the orthogonal experiment under various individual factors. These findings provide technical references for improving the crushing efficiency of concrete materials and the engineering application of HVPD crushing technology.

A matching and localization study of iliac bone graft for repair of talar cartilage injury secondary to lateral ankle instability.

Background: To investigate the search for an Iliac-Talar Grafts on the iliac bone that is morphologically matched to a multiplanar injury lesion of the talus; while utilizing a bone-harvesting guide to ensure precise positioning of the Iliac-Talar Grafts. Methods: A total of twenty-two cases with both talar CT data and iliac CT data were collected from January 2019 to June 2023. One case each of talar deformity injury and bone disease were excluded, resulting in a selection of 20 cases. The medial and lateral target repair areas of the talus were formulated, and virtual surgery was performed by using digital orthopedic technology to locate an iliac-talar restoration on the iliac bone that matched the morphology of the multiplanar injury lesion of the talus. 3D chromatographic deviation analysis was used to assess the accuracy of Iliac-Talar Grafts in terms of morphometric matching and positioning, while personalized iliac bone extraction guides were designed to ensure accurate positioning of the Iliac-Talar Grafts. Results: The best fitting point for repairing the medial talar lesion is determined to be medial to the anterior iliac crest, specifically 2.935 ± 0.365 cm posterior to the anterior superior iliac spine, and 2.550 ± 0.559 cm anterior to the valgus-iliac crest point (VICP). Similarly, for the repair of the lateral talar lesion, the ideal position is found to be lateral to the posterior iliac crest, approximately 2.695 ± 0.640 cm posterior to the valgus-iliac crest point (VICP). Utilizing bone extraction guides enables precise positioning for iliac bone extraction. Conclusion: This study utilizes virtual surgery, 3D chromatographic deviation analysis, and guide plate techniques in digital orthopedics to precisely locate the Iliac-Talar Graft on the iliac bone, matching the morphology of the talar lesion; it provides a new solution for cutting the iliac bone implant that matches the the multifaceted talar lesion to be repaired.

LncRNA PITPNA-AS1 mediates the diagnostic potential of miR-129-5p in prostate cancer.

BACKGROUND: LncRNA has an effective value in many diseases, which has long been applied in the diagnosis, treatment and prognosis of prostate cancer. This study focused on lncRNA PITPNA-AS1, and its diagnostic potential in prostate cancer has been explored. METHODS: The expression of PITPNA-AS1 and miR-129-5p in prostate cancer serum and sample cells was determined by real-time quantitative polymerase chain reaction (RT-qPCR). The relationship between the expression of PITPNA-AS1 and clinicopathological parameters was considered. ROC curve prompted the diagnostic value of PITPNA-AS1. The effect of PITPNA-AS1 on prostate cancer cells was verified using vitro cells assay. Luciferase activity assay and RIP assay demonstrated the sponge relationship of PITPNA-AS1 to miR-129-5p. RESULTS: PITPNA-AS1 level was increased, while miR-129-5p was obviously decreased in prostate cancer. PITPNA-AS1 expression was associated with Gleason grade, lymph node metastasis and TNM stage in patients. The area under the curve (AUC) was 0.910, with high sensitivity and specificity. PITPNA-AS1 was elucidated to directly target miR-129-5p, whereas silencing PITPNA-AS1 negatively affected prostate cancer cell proliferation, migration and invasion. Intervention of miR-129-5p inhibitor reversed the effect of silencing PITPNA-AS1 on cells. CONCLUSIONS: PITPNA-AS1 was relatively highly expressed in prostate cancer and mediated the pathophysiological process of patients, which may serve as a diagnostic indicator. Silencing of the PITPNA-AS1 sponge miR-129-5p inhibited the biological function of the cells, indicating that PITPNA-AS1 may represent a novel therapeutic target for prostate cancer.

Inspection of defects in composite structures using long pulse thermography and shearography.

Long pulse thermography (LPT) and shearography have been developed as primary methods for detecting debonding or delamination defects in composites due to their full-field imaging, non-contact operation, and high detection efficiency. Both methods utilize halogen lamps as the excitation source for thermal loading. However, the defects detected by the two techniques differ due to their distinct inspection mechanisms. In this study, LPT and shearography are employed to evaluate internal damage in various composite structures. The experimental results demonstrate that LPT, when combined with thermal signal processing algorithms, can clearly detect debonding defects in rubber-to-metal bonded plates, whereas excessive adhesive defects can only be identified by shearography. Flat-bottom holes in the CFRP panel can only be detected by LPT, and shearography is particularly effective for detecting composite materials with a metal skin. For the quantitative measurement of defect sizes, the average errors of the rubber-to-metal bonded plate and CFRP panel using LPT are 4.9 % and 2.2 %, respectively, whereas the average errors of the rubber-to-metal bonded plate and aluminum honeycomb panel using shearography are 15.12 % and 95.4 %, respectively. This indicates that LPT is superior to shearography in quantitatively measuring defect sizes. These two nondestructive testing methods, based on different principles, each have their own advantages and disadvantages. Employing a multi-modal inspection method can leverage their complementary advantages, preventing misdetection and leakage of internal defects in composites.

Effector Cs02526 from Ciboria shiraiana induces cell death and modulates plant immunity.

Sclerotinia disease is one of the most devastating fungal diseases worldwide, as it reduces the yields of many economically important crops. Pathogen-secreted effectors play crucial roles in infection processes. However, key effectors of Ciboria shiraiana, the pathogen primarily responsible for sclerotinia disease in mulberry (Morus spp.), remain poorly understood. In this study, we identified and functionally characterized the effector Cs02526 in C. shiraiana and found that Cs02526 could induce cell death in a variety of plants. Moreover, Cs02526-induced cell death was mediated by the central immune regulator brassinosteroid insensitive 1-associated receptor kinase 1, dependent on a 67-amino acid fragment. Notably, Cs02526 homologs were widely distributed in hemibiotrophic and necrotrophic phytopathogenic fungi, but the homologs failed to induce cell death in plants. Pretreatment of plants with recombinant Cs02526 protein enhanced resistance against both C. shiraiana and Sclerotinia sclerotiorum. Furthermore, the pathogenicity of C. shiraiana was diminished upon spraying plants with synthetic dsRNA-Cs02526. In conclusion, our findings highlight the cell death-inducing effector Cs02526 as a potential target for future biological control strategies against plant diseases.

Enhancing social media engagement using AI-modified background music: examining the roles of event relevance, lyric resonance, AI-singer origins, audience interpretation, emotional resonance, and social media engagement.

Introduction: Drawing on the S-O-R model, this study aims to investigate the influence of three stimuli from AI-modified music (i.e., event relevance, lyric resonance, and AI-singer origins), two responses from social media content consumers (i.e., audience interpretation and emotional resonance) on the social media engagement of personalized background music modified by artificial intelligence (AI). Methods: The structural equation modeling analyses of 467 social media content consumers' responses confirmed the role of those three stimuli and the mediating effect of audience interpretation and emotional resonance in shaping social media engagement. Results: The findings shed light on the underlying mechanisms that drive social media engagement in the context of AI-modified background music created for non-professional content creators. Discussion: The theoretical and practical implications of this study advance our understanding of social media engagement with AI-singer-originated background music and provide a basis for future investigations into this rapidly evolving phenomenon in the gig economy.

Identification of the KIF18A alpha-4 helix as a therapeutic target for chromosomally unstable tumor cells.

Background: The mitotic kinesin, KIF18A, is required for proliferation of cancer cells that exhibit chromosome instability (CIN), implicating it as a promising target for treatment of a subset of aggressive tumor types. Determining regions of the KIF18A protein to target for inhibition will be important for the design and optimization of effective small molecule inhibitors. Methods: In this study, we used cultured cell models to investigate the effects of mutating S284 within the alpha-4 helix of KIF18A, which was previously identified as a phosphorylated residue. Results: Mutations in S284 cause relocalization of KIF18A from the plus-ends of spindle microtubules to the spindle poles. Furthermore, KIF18A S284 mutants display loss of KIF18A function and fail to support proliferation in CIN tumor cells. Interestingly, similar effects on KIF18A localization and function were seen after treatment of CIN cells with KIF18A inhibitory compounds that are predicted to interact with residues within the alpha-4 helix. Conclusion: These data implicate the KIF18A alpha-4 helix as an effective target for inhibition and demonstrate that small molecules targeting KIF18A selectively limit CIN tumor cell proliferation and result in phenotypically similar effects on mitosis at the single cell level compared to genetic perturbations.

The feasibility study of stress position device simulating standing weight-bearing applied in computed tomography examination.

BACKGROUND: In order to simulate weight-bearing Computed Tomography (CT) examination, this study designed a simple stress position device. By analyzing the relevant data of stress position footprints and weight-bearing position footprints, the feasibility of the stress position device to simulate standing weight-bearing was verified. METHODS: This study randomly selected 25 volunteers for standing weight-bearing and stress position footprints collection, and measured the relevant indicators of stress position footprints and standing weight-bearing position footprints. Two foot and ankle surgeons conducted two measurements respectively on the footprints. Intra-observer and inter-observer reliability were calculated using intra-class correlation coefficients (ICC). Pearson correlation coefficient, ICC, scatter plot analysis, and paired t-test were used to analyze the stress and weight-bearing position data. RESULTS: The intra-observer and inter-observer measurement values were reliable. There was a certain degree of correlation between the stress position footprints and weight-bearing position footprints in terms of Pearson correlation coefficient, ICC, and scatter plot analysis. Paired t-tests showed significant differences in Clarke angle (t 2.636, p .012), C-S index (t 10.568, p .000), arch indx (t 2.176, p .035), and arch lower angle (t 6.246, p .000). CONCLUSION: The stress position device can generate a certain degree of stress, and after further optimization and improvement of the stress position device, it is feasible to apply it to weight-bearing CT examination in clinical settings.

[Effects of lncRNA SNHG12 on the proliferation, migration and invasiveness of prostate cancer cells by regulating E2F5 expression].

OBJECTIVE: To analyze the effects of lncRNA SNHG12 on the proliferation, migration and invasiveness of PCa cells by regulating the expression of E2F5. METHODS: Using real time fluorescence RT-PCR, we detected the expressions of lncRNA SNHG12 and E2F5, constructed the PC3 cells inhibiting the lncRNA SNHG12 expression. After transfection of the PC3 cells, we divided them into an NC, a si-NC, a si-SNHG12, a si-E2F5, a si-SNHG12+OE-si-NC, and a si-SNHG12+OE-E2F5 group, followed by examination of the proliferation, apoptosis, migration and invasiveness of the cells in different groups. RESULTS: The expressions of lncRNA SNHG12 and E2F5 were significantly up-regulated in the PCa tissue compared with those in the adjacent tissue (P < 0.05), remarkably higher in the DU145, LNCaP and PC3 groups than in the RWPE-1 group, the highest in the PC3 group (P < 0.05). The expression of SNHG12 was markedly down-regulated in the si-SNHG12 group (P < 0.05) in comparison with that in the si-NC group, indicating the successful construction of a PC3 cell line interfering with the lncRNA SNHG12 expression. Compared with the si-NC group, the si-SNHG12 group showed significant decreases in the values of CyclinD1, MMP-9 and OD and the numbers of migrating and invading cells, and an increase in apoptotic cells (P < 0.05), while the si-E2F5 group exhibited a remarkably down-regulated expression of E2F5 (P < 0.05), reduced values of CyclinD1, MMP-9 and OD, decreased numbers of migrating and invading cells and an increased number of apoptotic cells (P < 0.05). The dual luciferase report test showed that E2F5 reduced the luciferase activity of SNHG12 (P < 0.05 and had an insignificant impact on the luciferase activity of MUT-SNHG12 (P > 0.05). Inhibiting the expression of lncRNA SNHG12 resulted in significant decreases in the expression of E2F5, values of CyclinD1, MMP-9 and OD and numbers of migrating and invading cells, but an increase in apoptotic cells (P < 0.05). The E2F5 expression, the CyclinD1, MMP-9 and OD values and the numbers of migrating and invading cells were markedly increased while the number of apoptotic cells decreased in the si-SNHG12+OE-E2F5 group compared with those in the si-SNHG12+OE-si-NC group (P < 0.05). CONCLUSION: Interfering with the expression of lncRNA SNHG12 can regulate that of E2F5, inhibit the proliferation, migration and invasiveness of PCa cells and promote their apoptosis.

Discovery of GDC-0077 (Inavolisib), a Highly Selective Inhibitor and Degrader of Mutant PI3Kα.

Small molecule inhibitors that target the phosphatidylinositol 3-kinase (PI3K) signaling pathway have received significant interest for the treatment of cancers. The class I isoform PI3Kα is most commonly associated with solid tumors via gene amplification or activating mutations. However, inhibitors demonstrating both PI3K isoform and mutant specificity have remained elusive. Herein, we describe the optimization and characterization of a series of benzoxazepin-oxazolidinone ATP-competitive inhibitors of PI3Kα which also induce the selective degradation of the mutant p110α protein, the catalytic subunit of PI3Kα. Structure-based design informed isoform-specific interactions within the binding site, leading to potent inhibitors with greater than 300-fold selectivity over the other Class I PI3K isoforms. Further optimization of pharmacokinetic properties led to excellent in vivo exposure and efficacy and the identification of clinical candidate GDC-0077 (inavolisib, 32), which is now under evaluation in a Phase III clinical trial as a treatment for patients with PIK3CA-mutant breast cancer.

Ballistic Limit of UHMWPE Composite Armor under Impact of Ogive-Nose Projectile.

The ballistic response of armor has been widely used to evaluate its feasibility and advantages as a protective structure. To obtain the ballistic performance and ballistic limitations of composite armor, a type of ultra-high molecular weight polyethylene (UHMWPE) composite armor is designed, which is composed of UHMWPE laminates and steel face sheets of Q235. The total thickness of the armor is 53 mm, with an in-plane dimension of 300 mm × 300 mm. Then, an experimental study of the ballistic impact response of composite armor subject to a typical ogive-nose projectile was carried out. In the velocity range of 501.1 to 1026.1 m/s, the 14.5 mm caliber armor-piercing projectile could penetrate through the composite armor. At the velocity of 433.3 m/s, the A-P projectile was embedded in the armor, leaving a bulge mark on the back sheet. Therefore, 467.2 m/s is taken as the ballistic limit of the armor under the impact of the ogive-nose projectile. In addition, a corresponding numerical simulation model is also established to predict the ballistic limit of the projectile. The numerical predictions are consistent with the experimental results. The ballistic limit obtained from the numerical simulation results is 500 m/s, which is acceptable with a relative error of 7.02%. The failure mechanism of the composite armor is also obtained. Petaling is the main dominant failure mode for both face sheets, while delamination and shear failure dominate the penetration process of UHMWPE laminates. Finally, the perforation mechanism of composite armor under the impact of an A-P projectile is analyzed with theoretical models to predict the residual velocity, the work performed during the perforation, and the resisting stress of σs in the cavity-expansion model. The experimental and numerical simulation results can provide necessary data in the analysis of the composite structure's dynamic response under the impact of sharp head penetrators. The research results present the ballistic performance, failure mechanism, and ballistic limit of the composite armor under the impact of a typical ogive-nose projectile, which can be significant in the design of composite armor in the areas of ship shield, fortifications protection, and bulletproof structures against threats from sharp head penetrators.

Analysis of risk factors for bile duct injury in laparoscopic cholecystectomy in China: A systematic review and meta-analysis.

BACKGROUND: To explore the risk factors of bile duct injury in laparoscopic cholecystectomy (LC) in China through meta-analysis. METHODS: The study commenced with a search and selection of case-control studies on the risk factors for bile duct injury in LC in China using the following databases: PubMed, EMBASE, ScienceNet.cn, CNKI, Wanfang Data, and VIP. Data were extracted from the collected documents independently by 2 researchers, following which a meta-analysis of these data was performed using Revman 5.3. RESULTS: The compilation of all data from a total of 19 case-control studies revealed that among 41,044 patients, 458 patients experienced bile duct injury in LC, accounting for the incidence rate of 1.12% for bile duct injury. The revealed risk factors for bile duct injury were age (≥40 years) (odds ratio [OR] = 6.23, 95% CI [95% confidence interval]: 3.42-11.33, P < .001), abnormal preoperative liver function (OR = 2.01, 95% CI: 1.50-2.70, P < .001), acute and subacute inflammation of gallbladder (OR = 8.35, 95% CI: 5.32-13.10, P < .001; OR = 4.26, 95% CI: 2.73-6.65, P < .001), thickening of gallbladder wall (≥4 mm) (OR = 3.18, 95% CI: 2.34-4.34, P < .001), cholecystolithiasis complicated with effusion (OR = 3.05, 95% CI: 1.39-6.71, P = .006), and the anatomic variations of the gallbladder triangle (OR = 11.82, 95% CI: 6.32-22.09, P < .001). However, the factors of gender and overweight (body mass index ≥ 25 kg/m2) were not significantly correlated with bile duct injury in LC. CONCLUSIONS: In the present study, age (≥40 years), abnormal preoperative liver function, gallbladder wall thickening, acute and subacute inflammation of the gallbladder, cholecystolithiasis complicated with effusion, and anatomic variations of the gallbladder triangle were found to be closely associated with bile duct injury in LC.

Dynamic Response of UHMW-PE Composite Armors under Ballistic Impact of Blunt Projectiles.

To study the dynamic response of UHMW-PE composite armor under ballistic impact, two kinds of UHMW-PE composite armors are designed. Both of them are composed of UHMW-PE laminates and steel face sheets of Q235. The blunt projectile is made of 35CrMnSiA, with a cylinder shape. By numerical simulation, the dynamic response and deformation of composite armors are obtained under the penetration of the projectile. With the increase of impact velocity, the penetration depth increases nearly linearly, with a more severe tendency of swaging in the projectile. Then, experiments are carried out to validate the numerical simulation results. Based on a ballistic gun with a caliber of 14.5 mm, the projectiles are fired with a velocity from 680 m/s to 1300 m/s. The penetration into the composite armor can be divided into an initial shear plugging stage and the following bulging and delamination stage. Based on the theoretical analysis, the shear strength in the shear plugging stage can be estimated. Associated with typical experimental results, numerical simulation is suitable to predict the bulging characteristics of the composite armor. The failure mode of the composite armors under the impact of blunt projectiles is determined, and the failure mechanism is analyzed. The penetration results in the experiment agree well with the numerical simulation results, which validate the correctness of the numerical simulation models. The research results can be significant in the design of composite armor with UHMW-PE laminates.

Ligamentous injury-induced ankle instability causing posttraumatic osteoarthritis in a mouse model.

BACKGROUND: This study aims to explore the relationship between surgically-induced ankle instability and posttraumatic osteoarthritis (PTOA) in a mouse model, and to provide reference for clinical practice. RESULTS: Ligamentectomy was performed on 24 eight-week-old male C57BL/6 J mice, which were divided into three groups. Both the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) were severed in the CFL + ATFL group, while only the CFL was removed in the CFL group. The SHAM group was set as the blank control group. A wheel-running device was used to accelerate the development of ankle osteoarthritis (OA). Balance measurement, footprint analysis, and histological analysis were used to assess the degree of ankle instability and OA. According to the balance test results, the CFL + ATFL group demonstrated the highest number of slips and the longest crossing beam time at 8 weeks postoperatively. The results of gait analysis exhibited that the CFL + ATFL group had the most significant asymmetry in stride length, stance length, and foot base width compared to the CFL and SHAM groups. The OARSI score of the CFL + ATFL group (16.7 ± 2.18) was also much higher than those of the CFL group (5.1 ± 0.96) and the SHAM group (1.6 ± 1.14). CONCLUSION: Based on the mouse model, the findings indicate that severe ankle instability has nearly three times the chance to develop into ankle OA compared to moderate ankle instability.

Biomethane enhancement from corn straw using anaerobic digestion by-products as pretreatment agents: A highly effective and green strategy.

The development of biogas projects feed by lignocellulosic biomass has been constrained by the high cost of pre- and post-treatment. In this study, a novel strategy for pretreatment by using two by-products, i.e., CO2 and liquid digestate (LD), generated from anaerobic digestion (AD) was developed to overcome these shortcomings. Results showed that corn straw pretreated in LD pressurized under 1 Mpa CO2 at 55 â„ƒ resulted in increased glucose and xylose contents and a 9.80% decrease in cellulose crystallinity. After 45 days of AD conversion, the methane yield increased by 50.97% compared with untreated straw. However, pretreatment in LD pressurized under 1 Mpa CO2 at 170 â„ƒ produced 5-hydroxymethylfurfural and furfural, which led to a decrease in methane production from the straw in the subsequent AD conversion. The alteration of the microbial community in the pretreated slurry at 55 °C was another potential contributor to the enhanced performance of AD.

Dynamic Behavior Analysis and Stability Control of Tethered Satellite Formation Deployment.

In recent years, Tethered Space Systems (TSSs) have received significant attention in aerospace research as a result of their significant advantages: dexterousness, long life cycles and fuel-less engines. However, configurational conversion processes of tethered satellite formation systems in a complex space environment are essentially unstable. Due to their structural peculiarities and the special environment in outer space, TSS vibrations are easily produced. These types of vibrations are extremely harmful to spacecraft. Hence, the nonlinear dynamic behavior of systems based on a simplified rigid-rod tether model is analyzed in this paper. Two stability control laws for tether release rate and tether tension are proposed in order to control tether length variation. In addition, periodic stability of time-varying control systems after deployment is analyzed by using Floquet theory, and small parameter domains of systems in asymptotically stable states are obtained. Numerical simulations show that proposed tether tension controls can suppress in-plane and out-of-plane librations of rigid tethered satellites, while spacecraft and tether stability control goals can be achieved. Most importantly, this paper provides tether release rate and tether tension control laws for suppressing wide-ranging TSS vibrations that are valuable for improving TSS attitude control accuracy and performance, specifically for TSSs that are operating in low-eccentricity orbits.

Energy-Optimal Latency-Constrained Application Offloading in Mobile-Edge Computing.

Mobile-edge computation offloading (MECO) is a promising emerging technology for battery savings in mobile devices (MD) and/or in latency reduction in the execution of applications by (either total or partial) offloading highly demanding applications from MDs to nearby servers such as base stations. In this paper, we provide an offloading strategy for the joint optimization of the communication and computational resources by considering the blue trade-off between energy consumption and latency. The strategy is formulated as the solution to an optimization problem that minimizes the total energy consumption while satisfying the execution delay limit (or deadline). In the solution, the optimal transmission power and rate and the optimal fraction of the task to be offloaded are analytically derived to meet the optimization objective. We further establish the conditions under which the binary decisions (full-offloading and no offloading) are optimal. We also explore how such system parameters as the latency constraint, task complexity, and local computing power affect the offloading strategy. Finally, the simulation results demonstrate the behavior of the proposed strategy and verify its energy efficiency.

Multi-objective Informative Frequency Band Selection Based on Negentropy-induced Grey Wolf Optimizer for Fault Diagnosis of Rolling Element Bearings.

Informative frequency band (IFB) selection is a challenging task in envelope analysis for the localized fault detection of rolling element bearings. In previous studies, it was often conducted with a single indicator, such as kurtosis, etc., to guide the automatic selection. However, in some cases, it is difficult for that to fully depict and balance the fault characters from impulsiveness and cyclostationarity of the repetitive transients. To solve this problem, a novel negentropy-induced multi-objective optimized wavelet filter is proposed in this paper. The wavelet parameters are determined by a grey wolf optimizer with two independent objective functions i.e., maximizing the negentropy of squared envelope and squared envelope spectrum to capture impulsiveness and cyclostationarity, respectively. Subsequently, the average negentropy is utilized in identifying the IFB from the obtained Pareto set, which are non-dominated by other solutions to balance the impulsive and cyclostationary features and eliminate the background noise. Two cases of real vibration signals with slight bearing faults are applied in order to evaluate the performance of the proposed methodology, and the results demonstrate its effectiveness over some fast and optimal filtering methods. In addition, its stability in tracking the IFB is also tested by a case of condition monitoring data sets.