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In this article, we consider the following fractional (p , q) -Laplacian problem (− Δ) p s 1 u + (− Δ) q s 2 u + V (x) (| u | p − 2 u + | u | q − 2 u) = f (u) + λ | u | r − 2 u , where x ∈ R N , (− Δ) p s 1 is the fractional p-Laplacian operator ( (− Δ) q s 2 is similar), 0 < s 1 < s 2 < 1 < p < q < N s 2 , q s 2 * = N q N − s 2 q , r ≥ q s 2 * , f is a C 1 real function and V is a coercive function. By using variational methods, we prove that the above problem admits a sign-changing solution if λ > 0 is small. [ABSTRACT FROM AUTHOR]

In this paper, we are concerned with the Kirchhoff-type variable-order fractional Laplacian problems involving critical exponents and logarithmic nonlinearity. By using the constraint variational method, we show the existence of one least energy sign-changing solution. Moreover, we show that this energy is strictly larger than twice the ground energy. [ABSTRACT FROM AUTHOR]

The K-core of a graph is the unique maximum subgraph within which each vertex connects to K or more other vertices. The optimal K-core attack problem asks to delete the minimum number of vertices from the K-core to induce its complete collapse. A hierarchical cycle-tree packing model is introduced here for this challenging combinatorial optimization problem. We convert the temporally long-range correlated K-core pruning dynamics into locally tree-like static patterns and analyze this model through the replica-symmetric cavity method of statistical physics. A set of coarse-grained belief propagation equations are derived to predict single vertex marginal probabilities efficiently. The associated hierarchical cycle-tree guided attack (hCTGA) algorithm is able to construct nearly optimal attack solutions for regular random graphs and Erdös-Rényi random graphs. Our cycle-tree packing model may also be helpful for constructing optimal initial conditions for other irreversible dynamical processes on sparse random graphs. [ABSTRACT FROM AUTHOR]

In this paper, we consider the nonlinear impulsive generalized fractional differential equations with (p , q) -Laplacian operator for 1 < p ≤ q < ∞ , in which the nonlinearity f contains two fractional derivatives with respect to another function. Since the complexity of the nonlinear term and the impulses exist in generalized fractional calculus, it is difficult to find the corresponding variational functional of the problem. The existence of nontrivial solutions for the problem is established by the mountain pass theorem and iterative technique under some appropriate assumptions. Furthermore, our main result is demonstrated by an illustrative example to show its feasibility and effectiveness. Due to the employment of a generalized fractional operator, our results extend some existing research findings. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aldehyded cellulose nanofibers/g-C 3 N 4 composite photocatalyst is fabricated. • The MCN-CNF A composite photocatalyst enables efficient photocatalytic H 2 O 2 production. • The multiple covalent/hydrogen bonds between MCN and CNF A is formed. • The electron transfer over the unique bridges of the multiple covalent/hydrogen bonds is thoroughly demonstrated. Photo-driven H 2 O 2 production by graphitic carbon nitride (g-C 3 N 4) using H 2 O and O 2 is a sustainable alternative to fossil fuels, but pristine g-C 3 N 4 is typically limited by inefficient charge transfer and separation. Many research works have focused on the construction of catalyst heterojunction, doping and defect engineering with electron migration for enhanced H 2 O 2 synthesis, while also damaging the intrinsic crystal structure of the catalysts. Herein, a "living" aldehyded cellulose nanofibers (CNF A) are anchored onto g-C 3 N 4 with multiple hydrogen and covalent bonding. Moreover, the CNF A incorporation is found to dominantly increase the wettability of g-C 3 N 4 and promote the adsorption of molecular oxygen. Batch experiments and DFT calculations further confirm that high-quality interfacial hydrogen and covalent bonding between CNF A and g-C 3 N 4 with boosting transfer of photogenerated electrons, leading enhanced single-electron oxygen reduction reaction (ORR) for H 2 O 2 generation. The optimized photocatalytic H 2 O 2 of resultant MCN-CNF A is 67.44 μmol/L, surpassing four-folds of pristine MCN. This work provides an eco-friendly design of active cellulose nanofibers, which efficiently tunes the intramolecular charge transfer of g-C 3 N 4 -based photocatalysts for H 2 O 2 generation. [ABSTRACT FROM AUTHOR]

This paper discusses a kind of coupled nonlocal Laplacian evolution equation with Caputo time-fractional derivatives and proportional delays. Green function and mild solution are firstly established by employing the approach of eigenvalues' expansions and Fourier analysis technique. By the properties of eigenvalues and Mittag–Leffler functions, several vital estimations of Green functions are presented. In view of these estimations and some appropriate assumptions, the existence and uniqueness of the mild solution are studied by utilizing the Leray–Schauder fixed-point theorem and the Banach fixed-point theorem. Finally, an example is provided to illustrate the effectiveness of our main results. [ABSTRACT FROM AUTHOR]

In this paper, we consider the following Kirchhoff problem − a + b ∫ R 3 ∇ u 2 d x Δ u + λ V x u = u p − 2 u , in R 3 u ∈ H 1 R 3 where a , b > 0 are constants, λ is a positive parameter, and 4 < p < 6. Under suitable assumptions on V x , the existence of nontrivial solution is obtained via variational methods. The potential V x is allowed to be sign-changing. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to study a piezoelectric energy harvester in the form of vortex oscillation for fixed disturbance fluid type. The harvester consists of a fixed cylinder, an oscillating cylinder, flexible beams, and polyvinylidene fluorides (PVDFs). The flexible beam connects the fixed cylinder to the oscillating cylinder, and the PVDF is fixed to the flexible beam by means of adhesive, thus completing the assembly of the entire energy harvester. In this paper, the diameters of the fixed cylinder and oscillating cylinder and the length of the flexible beam are studied. In different parameter states, the harvester has different output performance; so the purpose of this study is to find a set of optimum parameters that will lead to the best harvester output. When the diameters of the fixed cylinder and oscillating cylinder are 50 and 20 mm, respectively, and the length of the flexible beam is 60 mm, the whole prototype has the best electrical output performance with 5.98 µW power at 18 m/s. The whole prototype is sensitive to excitation at any wind speed and is able to convert and collect even weak streaming excitation energy from the environment. This structure offers greater reliability and durability than the disturbed fluid oscillation type piezoelectric harvester. [ABSTRACT FROM AUTHOR]

This paper proposes a cam frequency-increasing hybrid piezoelectric electromagnetic energy harvester with center symmetric structure (C-HEH). The use of the cam structure allows the harvester to increase the efficiency of energy harvester per unit time, while the center symmetric structure of the entire harvester allows for maximum energy output in a limited size. This paper studies the influence of the number of cam protrusions and the length of the cylindrical permanent magnet on the output voltage signal at different rotation speeds. When the number of cam protrusions is 3 and the length of the cylindrical magnet is 10 mm, the maximum peak-to-peak voltages of the piezoelectric and the electromagnetic power generation unit are 53.74 V and 3.16 V, respectively. The effective value power of the hybrid energy harvester can be obtained as 1.49 mW. A series of application experiments were carried out to verify the performance of the C-HEH. The hybrid energy harvester can easily light up 86 light-emitting diodes (LEDs) lights and make the scientific calculators work stably after rectification. These results demonstrate the giant prospect of piezoelectric-electromagnetic energy harvesters for supplying wireless sensor networks and low-power electronic devices. [ABSTRACT FROM AUTHOR]

Using perovskite solar cells due to their lightweight, cost-effective, and adaptable nature, is regarded as one of the most encouraging renewable energy options. So, improving the stability of this semiconductor device is very important. One of the suggestions for improving the dynamic stability of this structure is choosing laminated composite layers with various angle ply as the metal layer. So, in this work, for the first time, absorbed energy capacity, and dynamics of improved perovskite solar cells via both mathematical modeling and a hybrid machine learning method is presented. Laminated composite layers are placed in the last layer of the solar cell so that it can improve the energy absorption and dynamics of this kind of semiconductor device. So, with this assumption, in the current work, absorbed energy capacity dynamic deflection and natural frequency sensitivity analysis of solar doubly curved cells with respect to geometrical and physical parameters is carried out. High-order shear deformation theory, which displays the parabolic transverse shear stresses throughout the thickness by satisfying the free surface requirements, is employed in this work to simulate the displacement field. The governing equations with varied boundary conditions are generated and solved, accordingly, using the virtual work principle and exact solution. After obtaining the dataset using mathematical simulation, a hybrid machine learning method using coupled support vector machine (SVM), genetic algorithm (GA), and Particle swarm optimization (PSO) is used to test, train, and validate the outputs. After that, the SVM-PSO-GA algorithm is used to validate the current work's results. Lastly, some detailed recommendations for enhancing the stability of solar cells are provided. [ABSTRACT FROM AUTHOR]

This article considers the biharmonic equation Δ 2 u = K (x) f (u) in R N. Under suitable assumptions, the existence of positive solutions is obtained. The methods used here contain the integral operator and the Schauder fixed point theory. Since the form of fundamental solution of Δ 2 u = 0 in R N depends on N, we divide our discussions into three cases as (a) N = 2 ; (b) N = 4 ; (c) N > 2 but N ≠ 4 . The fundamental solution of Δ 2 plays an essential role in our results. [ABSTRACT FROM AUTHOR]

AbstractThe continuous integration and refinement of electronic equipment results in the more stringent requirements for epoxy resin (EP) based materials, such as excellent heat dissipation and low coefficient of thermal expansion (CTE). In order to improve the dispersion of silica powder (SP) in EP and thus expand the application of EP in the field of electronic packaging, our research described in this paper adopted the KH-550 coupling agent to modify the surface of SP (m-SP). The effects of KH-550 coupling agent on the characteristics of the composites were investigated in terms of thermal, rheological, electrical insulation and mechanical properties. The results showed that when the content of KH-550 was 2 wt% of the fillers, the best modification effect was achieved, and the surface properties of the fillers were changed accordingly. In particular, the materials filled with m-SP exhibited lower viscosity end, better mechanical and electrical insulation properties. It was also found that the adding of the KH-550 had different effects on the thermal degradation, dynamic thermo-mechanical properties and the thermal deformation behavior of the materials. According to our study, the thermal conductivity and the CTE of m-SP/EP filled with 70 wt% of modified fillers were 0.787 W/m.K and 28.3 ppm/°C respectively, corresponding to a significant thermal conductivity improvement and low CTE. [ABSTRACT FROM AUTHOR]

Artificial neural networks can achieve impressive performances, and even outperform humans in some specific tasks. Nevertheless, unlike biological brains, the artificial neural networks suffer from tiny perturbations in sensory input, under various kinds of adversarial attacks. It is therefore necessary to study the origin of the adversarial vulnerability. Here, we establish a fundamental relationship between geometry of hidden representations (manifold perspective) and the generalization capability of the deep networks. For this purpose, we choose a deep neural network trained by local errors, and then analyze emergent properties of the trained networks through the manifold dimensionality, manifold smoothness, and the generalization capability. To explore effects of adversarial examples, we consider independent Gaussian noise attacks and fast-gradient-sign-method (FGSM) attacks. Our study reveals that a high generalization accuracy requires a relatively fast power-law decay of the eigen-spectrum of hidden representations. Under Gaussian attacks, the relationship between generalization accuracy and power-law exponent is monotonic, while a non-monotonic behavior is observed for FGSM attacks. Our empirical study provides a route towards a final mechanistic interpretation of adversarial vulnerability under adversarial attacks. [ABSTRACT FROM AUTHOR]

In this paper, we prove the multiplicity of nontrivial solutions for a class of fractional-order elliptic equation with magnetic field. Under appropriate assumptions, firstly, we prove that the system has at least two different solutions by applying the mountain pass theorem and Ekeland's variational principle. Secondly, we prove that these two solutions converge to the two solutions of the limit problem. Finally, we prove the existence of infinitely many solutions for the system and its limit problems, respectively. [ABSTRACT FROM AUTHOR]

The existing of avidity cancer stem cells (CSCs) made it an optical strategy to kill cancer cells and CSCs at the same time. Here, we constructed a CSCs specific nanocarrier naming T-S-NLC using the CD133+ targeting peptide TISWPPR (TR) as the targeting moiety attached to the distal end of PEG on salinomycin (Sal) loaded nanostructured lipid carriers (NLC), its pharmaceutical characteristics proved it 128.73 ± 2.09 nm, anionic spheroid with sustained release profile. It's in vitro targeting effect in CD133+ CSCs indicated that it exhibited superior CSCs internalization over non-modified NLC or free drug. Afterwards, it was used in combination with previously designed EGFR specific A-P-NLC (AEYLR peptide-PEG-modified paclitaxel loaded NLC) to achieve the goal to kill the cancer cells and CSCs, simultaneously. The in vitro tumor targeting effect of T-S-NLC + A-P-NLC was affirmed by cellular uptake and proliferation inhibition effect in NCI-H1299 and S180 cell lines showing advanced results over single preparation groups. In vivo tumor targeting effect in S180 tumor-bearing mice also validated the better tumor accumulative effect of the combined group. Last but not least, the in vivo antitumor effect strongly identified the greater tumor suppression effect of T-S-NLC + A-P-NLC than single preparation groups or combined use of free drugs while maintaining a good living state of the mice. To sum up, the combined usage of PTX and Sal active targeting NLC naming A-P-NLC + T-S-NLC which killed cancer cells and CSCs at the same time was a promising drug delivery system. [ABSTRACT FROM AUTHOR]

Lethal‑7 (let‑7) microRNA (miRNA) serves a pivotal role in a number of physiological processes and is associated with the occurrence and development of multiple disorders such as cancer. The present study aimed to use a newly developed stem‑loop strategy for reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) to distinguish let‑7 miRNA family members that differ by as little as a single nucleotide. For the miRNAs comprising 16 identical nucleotides at the 5'‑end, different stem‑loop RT primers were designed and used in RT‑qPCR to assess the expression profiles of a panel of let‑7 family member miRNAs in human glioblastoma U87 cells. Amplification efficiency was evaluated through correlation analysis between total RNA input and the quantification threshold values. Melting curve profiles were measured to estimate the amplification specificity of the improved stem‑loop RT‑qPCR compared with those of the poly(A)‑tailing method. In addition, the discrimination ability of the modified stem‑loop method was examined. Compared with poly(A) tailing, the modified stem‑loop RT method was able to specifically reverse transcribe the diverse let‑7 miRNA family members followed by accurate quantification, with a theoretical amplification efficiency of ~100%. This modified stem‑loop method was able to distinguish miRNAs with a single base difference. This innovative method may be used in the clinical detection of let‑7 expression levels in a variety of tumour samples, and may provide valuable data for disease diagnosis and prognostic evaluation. In addition, this method may offer a new avenue for developing particular stem‑loop approaches in measuring other miRNAs with little discrepancy. [ABSTRACT FROM AUTHOR]

In this paper, we present a recent approach via variational methods and critical point theory to obtain the existence of periodic solutions for a class of delay Hamiltonian systems on time scales with impulsive effects. The variational principle is given, and some existence theorems and two multiplicity results of periodic solutions are obtained. Finally, one example is presented to illustrate the feasibility and effectiveness of our results. Our results are new even in both the differential equations case and the difference equations case. [ABSTRACT FROM AUTHOR]

Global efforts are being made to achieve ecological sustainability while reducing the consequences of environmental degradation. We used panel data from Brazil, Russia, India, China, and South Africa (BRICS countries), spanning 2000 to 2020, to examine the interactions between economic growth, green financing, green credit, renewable energy investment, geopolitical risk (GPR), and environmental sustainability. To explore the short- and long-term connections between the series, we used the cross-sectional augmented distributed lag (CS-ARDL) econometric method. We found that increasing green financing, renewable energy investment, and energy innovation by 0.05% reduced environmental pollution. Moreover, GPR shocks have long-term beneficial effects on green finance development. We also found that the adoption of renewable energy in BRICS countries is significantly and favourably impacted by GPR. This study is groundbreaking because it is the first to examine the interplay between green financing, geopolitical risk, and environmental tax nexus in renewable energy investments, all of which play critical roles in achieving ecological sustainability and yield valuable insights for policymakers working towards the realization of sustainable development goals. • To explore the short- and long-term connections this study used the CS-ARDL econometrics method. • It has been shown that GPR shocks have long-term beneficial effects on green finance development. • We discover that adopting renewable energy in the BRICS is significantly impacted by GPR. [ABSTRACT FROM AUTHOR]

• Suction-repulsion action of magnetic force complete energy harvester. • Prototype increase the reliability of system compared with collision structure. • Hybrid mechanism solves the power limitation problem and improves output power. In this paper, a hybrid piezoelectric-electromagnetic energy harvester (HEH) based on magnetic couple suction-repulsion motion and centrifugal action is proposed. Using a control variable approach, the effect of two variables on the output performance was investigated under different parameter conditions in order to maximize the output power. At a mounting angle of 60 degrees for the piezoelectric cantilever beam and a mass of 3.2 g for the rectangular magnet, the entire piezoelectric-electromagnetic harvester can produce 13.32 mW of power, which can successfully power low-power electronic devices such as light-emitting diodes (LEDs). The power generated by mixing piezoelectricity and electromagnetism is 1.16 times greater than the power generated by the piezoelectric generation unit alone and 70.1 times greater than the power generated by the electromagnetic generation unit alone. The composite piezoelectric-electromagnetic hybrid mechanism greatly increases the power output of the entire structure compared to the single generation mode. The suction-repulsion process is accomplished using magnetic coupling. This makes the piezoelectric cantilever beam deformed by the magnetic force and has power output. At the same time, the magnetic suction-repulsion makes the circular magnet complete cutting magnetic induction line motion at the same time, which cleverly combines piezoelectricity and electromagnetism. The form of reciprocating motion of the magnet in the coil frame using suction-repulsion is also proposed for the first time. In addition, compared with those structures that strike the piezoelectric cantilever to generate electricity, this paper uses magnetic coupling, which makes the piezoelectric cantilever beam more durable and longer in use. In summary, this structure has good prospects for application in the direction of powering wireless networks or low-power electronic devices. [ABSTRACT FROM AUTHOR]

In this paper, the hydrodynamic characteristics of a piezoelectric micropump operate on the Coanda effect, and the mechanism of bi-directional pumping are analyzed by numerical simulation and experiments. The research focuses on the different positions of the fluid deflector and the influence on the output of the micropump. The results show that a closer fluid deflector to the inlet can produce greater vortices in the suction process due to the Coanda effect, and the backflow diminishing is more significant as well. Moreover, the different positions of the fluid deflector can cause a phenomenon that the micropump will achieve bi-directional pumping. As a finding, vortices arranged in pairs could improve the rectification efficiency of the micropump. The micropump achieves a maximum flow rate of 40.5 ml/min and back pressure of 5.76 cmH2o. In addition, the maximum flow rate per unit area can reach 305.2 µl/(min mm2). [ABSTRACT FROM AUTHOR]

Gliomas are the most common and aggressive primary tumors in the central nervous system. Recently, Max interactor-1 (MXI1), an antagonist of c-Myc that is involved in brain tumor progression, has been reported to be deregulated in a variety of tumors including glioma. However, the mechanism of MXI1 deregulation in gliomas remains unclear. In this study, we show that the relative expression level of MXI1 is markedly down-regulated in glioma cell lines. Using integrated bioinformatic analysis and experimental confirmation, we identified several miRNAs by screening a panel of predicted miRNAs that may regulate the MXI1 3′UTR. The strongest inhibitory miRNA, miR-155, can attenuate the activity of a luciferase reporter gene that is fused with the MXI1 3′UTR and decrease the expression levels of MXI1 mRNA and protein in U87 glioma cells. The potential role of miR-155 in promoting glioma cell proliferation by targeting MXI1 was confirmed in various glioma cell lines by rescue experiments using MTT assays, EdU incorporation assay, and cell counting experiments. In addition, we determined that the level of MXI1 mRNA was inversely correlated with the expression of miR-155 in 18 sets of glioblastoma multiforme specimens. These findings reveal for the first time that the targeting of MXI1 by miR-155 may result in a reduction in MXI1 expression and promote glioma cell proliferation; this result suggests a novel function of miR-155 in targeting MXI1 in glioma-genesis. [ABSTRACT FROM AUTHOR]

• Heat treatment and divalent cations had impact on the aggregation of β-lactoglobulin. • Ca2+ and Zn2+ increased the particle size of β-lactoglobulin aggregates. • Cu2+ effected the conformational structure of β-lactoglobulin strongly. • Free sulfhydryl content was significantly declined after Cu2+ treatment. • Cu2+ enhanced peptic digestion of β-lactoglobulin and decreased its antigenicity. Aggregation of bovine β-lactoglobulin is affected easily by external factors. In this study, effects of metal ions combining with temperature on aggregation of β-lactoglobulin were explored. The conformational characteristics of aggregates were detected by environment scanning electron microscope, CD spectrum and free sulfhydryl group, respectively. Digestive and immunological characteristics were assessed by simulated digestion in vitro and ELISA respectively. The results showed that the morphology of β-lactoglobulin aggregates became more amorphous in Cu2+ and Mg2+ treated samples and more constricted in Zu2+-induced protein. Among them, Cu2+ altered the secondary structure of β-lactoglobulin aggregates and free sulfhydryl content most as well as that in gastric digestion. However, all ion-treated groups had similar digestive stability in intestinal digestion. Specially, Ca2+ and Mg2+ made the antigenicity and potential allergenicity of β-lactoglobulin aggregates decrease, which helps us understand the role of metal ions in immunological characteristics. [ABSTRACT FROM AUTHOR]

This paper gives some results on almost automorphic strong solutions to time-fractional partial differential equations by employing a mix o thef Galerkin method, Fourier series, and Picard iteration. As an application, the existence, uniqueness, and global Mittag–Leffler convergence of almost automorphic strong solution are discussed to a concrete time-fractional parabolic equations. To the best of our knowledge, this is the first study on almost automorphic strong solutions on this subject. [ABSTRACT FROM AUTHOR]

In this paper, we present a recent approach via variational methods and critical point theory to obtain the existence of solutions for the second order Hamiltonian system on time scale $\mathbb{T}$ where u( t) denotes the delta (or Hilger) derivative of u at t, $u^{\Delta^{2}}(t)=(u^{\Delta})^{\Delta}(t)$, σ is the forward jump operator, T is a positive constant, A( t)=[ d( t)] is a symmetric N× N matrix-valued function defined on $[0,T]_{\mathbb{T}}$ with $d_{ij}\in L^{\infty}([0,T]_{\mathbb{T}},\mathbb{R})$ for all i, j=1,2,..., N, and $F:[0,T]_{\mathbb{T}}\times \mathbb{R}^{N}\rightarrow\mathbb{R}$. By establishing a proper variational setting, two existence results and two multiplicity results are obtained. Finally, three examples are presented to illustrate the feasibility and effectiveness of our results. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we study the Sobolev’s spaces on time scales and their properties. As applications, we present a recent approach via variational methods and the critical point theory to obtain the existence of solutions for a class of second order Hamiltonian systems on time scales. By establishing a proper variational setting, three existence results for systems under consideration are obtained. Finally, three examples are presented to illustrate the feasibility and effectiveness of the existence results. [Copyright &y& Elsevier]

Abstract: In this paper, a class of second-order Hamiltonian systems with impulsive effects are considered. We establish some sufficient conditions for the existence of solutions for the second-order Hamiltonian systems with impulsive effects where , , are continuous and . The solutions are sought by means of some critical point theorems. Finally, two examples are presented to illustrate the feasibility and effectiveness of our results. [Copyright &y& Elsevier]

Abstract: In this paper, we consider the existence and multiplicity of solutions for some Dirichlet impulsive problems and some existence and multiplicity results are obtained. The solutions are sought by means of Lax–Milgram theorem and some critical theorems. [Copyright &y& Elsevier]

• Using multiple groups of magnet coupling and plucking harvesters driven by inertial wheel. • In contrast to previous study, we have made a parametric study of the piezoelectric energy harvester structure. • It can generate milliwatt-level electrical energy at a smaller resonance frequency. Piezoelectric technology has attracted extensive attention and played an increasingly important role in the aspect of harvesting energy from the environment, which has advantages of simple structure, good performance, and so on. In this study, a multi-group dual piezoelectric energy harvester driven by inertial wheel with magnet coupling and plucking (M−PEH) is proposed. The M−PEH mainly includes a base, supports, piezoelectric patches, magnets, magnets cover, and rotor. This paper studies the series–parallel connection relationship between the circular and rectangular piezoelectric patches in the circumferential direction of the base, and the influence on the peak-to peak voltage when the length of the magnet extending from the surface of the rotor is different. Under the condition of inertial wheel 407 g, the M−PEH is tested and researched from 50 r/min to 600 r/min. After a series of experimental studies at 550 r/min, the peak-to-peak voltages of the circular and rectangular piezoelectric patches are respectively 15.00 V, 28.74 V, and 34.37 V, 67.19 V in the case of parallel and series connection when the length of the magnet protruding from the surface of the rotator is 7 mm. Besides that, under the condition of series connection, it is shown that the root-mean-square voltage and power of the circular and rectangular piezoelectric patches are 3.37 V, 0.054 mW, and 10.03 V, 0.80 mW, respectively at 550 r/min when the resistance is 100 kΩ. It can also easily light 47 light-emitting diodes (LEDs) under the excitation of 550 r/min. Therefore, the M−PEH can effectively collect energy under the drive of the inertia wheel and power the microelectronic devices. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we consider the existence and multiplicity of sign-changing solutions for some fourth-order nonlinear elliptic problems and some existence and multiple are obtained. The weak solutions are sought by means of sign-changing critical theorems. [Copyright &y& Elsevier]

Abstract: The main purpose of this paper is to study the following damped vibration problems with and where The variational sets are given and some multiplicity results of periodic solutions satisfying (1.1)–(1.3) are obtained. [Copyright &y& Elsevier]

In this paper, an integral valve is proposed by connecting the inlet cantilever valve and the outlet cantilever valve with a connecting post and a rubber circle plate structure. The integral valve changes the traditional inlet cantilever valve and outlet cantilever valve to work independently and realizes the joint response of the inlet cantilever valve and the outlet cantilever valve. The integral valve was designed, manufactured, and installed, and the performance of the static experimental test equipment of the valve and that of the experimental equipment of the piezoelectric pump were evaluated. The static performance of the integral valve was tested. In addition, the performance of the integral valve piezoelectric pump and the cantilever valve piezoelectric pump was tested and compared. The experimental results show that the integral valve piezoelectric pump reaches up to 270.2 ml/min at 210 Vrms, 45 Hz; the pressure can reach 86.2 cmH2O at 40 Hz. Compared to cantilever valves, integral valves have less forward flow resistance and better reverse shutoff. In particular, the pressure of the integral valve piezoelectric pump can be significantly improved compared to the cantilever valve piezoelectric pump. In terms of efficiency, the integrated valve piezoelectric pump will have better performance in the low-frequency region. [ABSTRACT FROM AUTHOR]

In this paper, we studied the existence of solutions for fractional differential equations of p-Laplacian with instantaneous and non-instantaneous impulses. The existence of solutions for a class of fractional differential equations with instantaneous and non-instantaneous impulses is obtained by using the critical point theory. Finally, an example is given to illustrate the feasibility of the main results. [ABSTRACT FROM AUTHOR]

A mirror-image rotating piezoelectric energy harvester is proposed, and it can adapt to 2.8 m/s — 13.6 m/s wind speed. It is arranged by the mirror image of two piezoelectric elements, so it has multiple resonant frequencies. The multiple resonant frequencies make the bandwidth of the energy harvester be broadened. The force applied on the piezoelectric beam is aperiodic and an evaluable analytical model is established based on Fourier series and superposition principle. The influence of the system parameters on the piezoelectric beam is deduced by the Bernoulli beam formula of axial direction, and a prototype is made for experiment and application. The results show that when the distance between the two magnets is kept at 15 mm, the torsion angle of the blades is 15°, three blades are selected, and the height of each blade is 50 mm, the power generation effect is optimal, and the power can reach 12.5 mW. Under the optimal power, it only takes 100s to charge the capacitor of 220 μF to 15V, the prototype can directly power 98 light emitting diodes (LEDs) and make the calculator work. This technology can also be extended for harvesting water energy. • The mirror image structure has multiple resonant frequencies. • The blades are designed to collect wind energy in multiple directions. • It can be extended to the collection of water energy. • Successfully powering micro and small electronic devices. [ABSTRACT FROM AUTHOR]

Syndecan-1 (SDC1) modified lipid bilayer (LB)-coated mesoporous silica nanoparticles (MSN) to co-deliver gemcitabine (GEM) and honokiol (HNK) were prepared for the targeting treatment of pancreatic cancer. The encapsulation efficiencies of GEM and HNK in SDC1-LB-MSN-GEM/HNK were determined to be 60.3 ± 3.2% and 73.0 ± 1.1%. The targeting efficiency of SDC1-LB-MSN-GEM/HNK was investigated in BxPC-3 cells in vitro. The fluorescence intensity in the cells treated with SDC1-LB-MSN-Cou6 was 2-fold of LB-MSN-Cou6-treated cells, which was caused by SDC1/IGF1R-mediated endocytosis. As anticipated, its cytotoxicity was significantly increased. Furthermore, the mechanism was verified that SDC1-LB-MSN-HNK induced tumor cell apoptosis through the mitochondrial apoptosis pathway. Finally, the biodistribution, tumor growth inhibition, and preliminary safety studies were performed on BALB/c nude mice bearing BxPC-3 tumor models. The tumor growth inhibition index of SDC1-LB-MSN-GEM/HNK was 56.19%, which was 1.45-fold and 1.33-fold higher than that of the free GEM/HNK and LB-MSN-GEM/HNK treatment groups, respectively. As a result, SDC1-LB-MSN-GEM/HNK combined advantages of both GEM and HNK and simultaneously targeted and eliminated pancreatic cancerous and cancer-associated stromal cells. In summary, the present study demonstrated a new strategy of synergistic GEM and HNK to enhance the therapeutic effect of pancreatic cancer via the targeting depletion of tumor stroma. [ABSTRACT FROM AUTHOR]

Valveless piezoelectric pumps usually have less flow than valve piezoelectric pumps, but the valve piezoelectric pumps have some limitations, such as high cost, complex structure, and difficult installation. In order to solve the problem of the low flow rate of the valveless piezoelectric pump, a valveless piezoelectric pump with multi-stage fluid guiding bodies is proposed. Based on the structure and working principle of the piezoelectric pump, the forward energy loss equation is established, and analysis on parameters affecting the energy loss of the pump is then conducted. COMSOL Multiphysics is adopted to construct a two-dimensional model of velocity and von Mises stress distribution. The valveless piezoelectric pumps were then fabricated based on 3D printing technologies, and the prototypes were tested. The results show that the output performance of the pump is the best when the working voltage is 220 V, the frequency is 95 Hz, the length of the oblique arm of the fluid guiding body is 3.5 mm, the spacing is 9.05 mm, and the thickness is 0.1 mm. The maximum flow rate is 520.6 ml/min. In addition, the experimental results prove that the asymmetric fluid guiding body placed in the center of the pump chamber can improve the performance of piezoelectric pumps. This study extends the application of piezoelectric valveless pumps in micromechanical cooling. [ABSTRACT FROM AUTHOR]

This paper researches a class of Caputo-Fabrizio fractional-order fuzzy competitive neural networks (CF-FCNNs) with different time scales and time delays. Firstly, according to Banach contracting mapping principle and some appropriate assumptions, it derives CF-FCNNs possess a unique weak solution. Then, exponential Euler difference scheme of discrete-time CF-FCNNs (DCF-FCNNs) is presented by the constant variation methods and the difference format is implicit Euler difference and is solved by fractional PECE algorithm. Next, the existence of a unique bounded asymptotically almost periodic sequence solution, global exponential stability and synchronization of DCF-FCNNs are considered. In the end, numerical examples are given to describe the effectiveness of the acquired conclusions. [ABSTRACT FROM AUTHOR]

H 2 O 2 production through solar-driven photocatalytic route has received increasing attention. Herein, a carbon ring incorporated hollow g-C 3 N 4 tubes (CHCN) was successfully fabricated via a novel supramolecular self-assembly strategy, co-inducing by hydrogen bond and covalent bond. The optimum H 2 O 2 yield over the CHCN-0.02 reached up to 1.58 mmol L−1 h−1 (AQE= 28.10%, 420 nm), which was 5.4 times significantly higher than that of bulk g-C 3 N 4 (0.29 mmol L−1 h−1) under visible light irradiation. Experimental and density functional theory (DFT) calculations revealed that the CHCNs not only expedited the charge carrier transfer/separation but also favored molecular oxygen adsorption and regulated bandgap structure under the in-plane electronic field induced by continuous π-conjugated C ring , which boosted the ORR efficiency for photocatalytic H 2 O 2 synthesis. The optimized CHCN catalyst demonstrated adequate hybrid ORR routes, consisting of a dominated selective one-step two-electron ORR pathway and highly efficient two-step single-electron ORR for H 2 O 2 production. Therefore, this work not only provides a new strategy for an efficient H 2 O 2 formation using a g-C 3 N 4 -based photocatalyst but also explores the functionary mechanism of the ORR process and enlightens the way to highly efficient H 2 O 2 generation. [Display omitted] • Facile synthesis of carbon rings-g-C 3 N 4 hollow tubes was achieved. • Intensified charge carriers transfer/separation across carbon rings-g-C 3 N 4 heterojunctions. • Efficient oxygen reduction reaction was regulated by TP derived carbon rings. • Remarkable photocatalytic H 2 O 2 generation by carbon rings-g-C 3 N 4 hollow tubes was revealed. [ABSTRACT FROM AUTHOR]

We are concerned with the following p-Laplacian equation - Δ p u + | u | p - 2 u = μ u + | u | s - 2 u , in R N , where - Δ p u = d i v (| ∇ u | p - 2 ∇ u) , 1 < p < N , μ ∈ R , s ∈ (N + 2 N p , p ∗) , p ∗ = Np N - p is the critical Sobolev exponent. Using constrained variational methods, we prove that the above problem has a normalized solution. Our contribution is that we can deal with the L 2 -supercritical case (N + 2 N p , p ∗) by a mountain-pass argument on the prescribed L 2 -norm constraint. [ABSTRACT FROM AUTHOR]

A delayed cellular neural networks with Caputo fractional-order derivative has been discussed in this paper. Firstly, the existence and uniqueness of S -asymptotically ω -periodic oscillation of the model are investigated by some important features of Mittag-Leffler functions and contraction mapping principle. Secondly, global asymptotical stability of the model is also studied by using Laplace transform, comparison principle and stability theorem of linear delayed Caputo fractional-order differential equations. Some better results are derived to improve and extend a few existing research findings. The research thoughts in this literature could be applied to research other fractional-order models in neural networks and physical areas. [ABSTRACT FROM AUTHOR]

We studied the unique kinematic properties in massive filament G352.63-1.07 at 103 au spatial scale with the dense molecular tracers observed with the Atacama Large Millimeter/submillimeter Array. We find the central massive core M1 (12 M ⊙) being separated from the surrounding filament with a velocity difference of v − v ¯ sys = − 2 km s − 1 and a transverse separation within 3″. Meanwhile, as shown in multiple dense-gas tracers, M1 has a spatial extension closely aligned with the main filament and is connected to the filament toward both its ends. M1 thus represents a very beginning state for a massive, young star-forming core escaping from the parental filament, within a timescale of ∼4000 yr. Based on its kinetic energy (3.5 × 1044 erg), the core escape is unlikely solely due to the original filament motion or magnetic field but requires more energetic events such as a rapid intense anisotropic collapse. The released energy also seems to noticeably increase the environmental turbulence. This may help the filament to become stabilized again. [ABSTRACT FROM AUTHOR]

Antibiotic resistance genes (ARGs) in environment have gradually engendered extensive concern recently due to the harm caused to environment and human beings. Wastewater treatment plants are considered as important nodes of ARGs controlling and it is of utmost importance to figure out effects and mechanisms of each process, especially disinfections. In this study, three disinfection processes (ultraviolet, chlorination, and ozone) were used to reduce levels of ARGs in secondary effluents from a municipal wastewater treatment plant. Results indicated that the abundance of ARGs decreased exponentially as the dosage increased during the ultraviolet disinfection treatment ( R 2 = 0.68–0.92). In the 0–5 mg/L available chlorine concentrations, with a contact time of 30 min, the abundance of ARGs decreased linearly as the chlorine concentrations increased ( R 2 = 0.77–0.99). In a 2 mg/L concentration of ozone (O 3 ), the abundance of ARGs had higher removal efficiency, but the removal efficiency was not significantly enhanced by increasing the concentration of ozone. However, an experiment using the DNase I treatment showed that UV and ozone disinfection resulted in apoptosis, and the bacterial DNA was released into the environment; ARGs were mostly found as free DNA in the treated wastewater. These results provide insights into behavior of ARGs during disinfection processes in wastewater treatment plants. [ABSTRACT FROM AUTHOR]

This paper presents a harvester that collects vibrational energy. The piezoelectric sheet deforms under mass inertia and then generates electricity according to the piezoelectric effect. At the same time, when designing the equipment, the incentive model is selected as the non-contact type to avoid mechanical collision and wear inside the structure and improve the service life of the device. An equivalent damping analysis is performed for the cantilever and combined with the control equations of the Lagrangian. The simulation analysis obtains the native frequency of the rectangular and circular piezoelectric sheets under the mode analysis. Through experimental proof that the device reaches the maximum output voltage 67.19 V when magnet 1 in the mass mutually repels magnet 1 in the housing and magnet 2 in the mass and magnet 2 in the housing. For an external resistance of 10 KΩ, the maximum power output of the device is 165 mW. The device can convert the vibrational energy in the environment into electricity and supply power to other devices through circuit storage. [ABSTRACT FROM AUTHOR]

In this paper, a compound cantilever beam based piezoelectric energy harvester (CCBPH) is proposed. This piezoelectric energy harvester uses vibrations caused by vortex excitation behind the winding fluid to harvest wind energy. In particular, this structure uses vortex excitation formed behind a vertically suspended cylindrical winding fluid to cause the vibration of the cylindrical winding fluid, which then indirectly excites the piezoelectric element. The CCBPH consists of a fixed support, a cantilever beam, magnet-1 and magnet-2, a support beam, two piezoelectric units-PVDF (polyvinylidene fluoride), a compound cantilever beam, and a cylindrical winding fluid. We investigated the parameters affecting the structure and verify the effectiveness of the energy harvester through the design of the structure, simulation analysis, and experiments. The experimental results show that the CCBPH can obtain the maximum output voltage from the energy harvester at a wind speed of 18 m/s. The maximum output power was achieved with an external load resistance of 2000 kΩ. By comparison, it is found that the maximum output power is 0.095 mW when the distance between two magnets is 20 mm and the mass ratio is 1:2 for copper. [ABSTRACT FROM AUTHOR]

"Driver gene-negative" lung adenocarcinoma (LUAD) was of rare treatment options and a poor prognosis. Presently, for them, few biomarkers are available for stratification analysis to make appropriate treatment strategy. This study aimed to develop a DNA-methylome-based signature to realize the precise risk-stratifying. Here, an Illumina MethylationEPIC Beadchip was applied to obtain differentially methylated CpG sites (DMCs). A four-CpG-based signature, named as TLA, was successfully established, whose prognosis-predicting power was well verified in one internal (n = 78) and other external (n = 110) validation cohorts. Patients with high-risk scores had shorter overall survival (OS) in all cohorts [hazard ratio (HR): 11.79, 5.16 and 2.99, respectively]. Additionally, it can effectively divide patients into low-risk and high-risk groups, with significantly different OS in the diverse subgroups stratified by the standard clinical parameters. As an independent prognostic factor, TLA may assist in improving the nomogram's 5-year OS-predicting ability (AUC 0.756, 95% CI:0.695–0.816), superior to TNM alone (AUC 0.644, 95% CI: 0.590–0.698). Additionally, the relationship of TLA-related genes, TAC1 , LHX9 , and ALX1 , with prognosis and tumour invasion made them serve as potential therapy targets for driver gene-negative LUAD. • The genome-wide methylome analysis highlighted DNA methylation's crucial role in "driver gene-negative" LUAD. • The methylation-based TLA signature can act as specific prognostic predictor that assist in optimizing treatment strategies. • The corresponding genes of TLA affected the progression that provide potential therapy targets for driver gene-negative LUAD. [ABSTRACT FROM AUTHOR]

This paper proposes a double-acting nonlinear wideband piezoelectric energy harvester under plucking and collision(W-PEH) for energy during rotation. The device is mainly composed of a base, rectangular piezoelectric patches, circular piezoelectric generating units and permanent magnets. The circular power generation units are constructed by using the nonlinear magnetic coupling mechanism and the contact frequency conversion principle. The nonlinearity caused by the magnetic force makes the circular piezoelectric power generation units work stably and efficiently at low speeds. And the contact-type collision excitation enables the circular piezoelectric patches inside the circular piezoelectric generating units to produce greater deformation and output a higher voltage. The rectangular piezoelectric patches are excited by the plucking, and the vibration amplitude is greater at high speeds, and it also produces a higher output voltage. Two different excitations make W-PEH's working frequency band wider, and the overall output voltage is also higher. The electromechanical coupling dynamics model of the system was constructed from Hamilton's principle and the magnetic dipole theory. The experimental results indicate that W-PEH can work effectively in different frequency bands. Under the load of 10 KΩ, the peak-to-peak power of the 150r/min integrated device is 0.350W, and that of the 450r/min integrated device is 0.107W. • Combines a nonlinear magnetic coupling with contact frequency conversion principle. • It works well under both low and high speeds excitation. • Two excitations make W-PEH's working frequency band wider, and the power is higher. • It can supply power for micro-electronic devices. [ABSTRACT FROM AUTHOR]

In this paper, a nonlinear piezoelectric energy harvester is developed based on rotational motion applications. It consists of the pedestal, the piezoelectric beam, the connection mass, the tip magnetic mass, the revolving host, the support frame, and the bolts. This device drives the intermittent magnetic vibration between the magnet and the tip magnetic mass to generate electric energy, avoids mechanical collision and wear, and extends the service life of the device. The working principle and vibration model of the proposed energy harvester are studied theoretically. The displacement state of the piezoelectric beam under a magnetic force is simulated and analyzed. In addition, a series of experiments verify the simulation results. With two driving magnets, 5 g tip magnetic mass, and 10 mm radial excitation distances, a piezoelectric energy harvester can capture energy efficiently. The results demonstrate that the piezoelectric energy harvester produces four resonance frequencies of 4, 11, 15, and 19 Hz. When the rotation frequency is 4 Hz, the maximum open-circuit voltage of the piezoelectric energy harvester is 96.87 V. The piezoelectric energy harvester gets the maximum average power of 8.97 mW when the external resistance is 300 kΩ. At this time, the voltage across the resistance is 51.87 V. [ABSTRACT FROM AUTHOR]

In recent years, the X-ray spectrometer has been developed not only just in enhancing resolution, but also towards dynamic analysis, computer modeling processing, sampled quantitative analysis and supra-light element analysis. With the gradual sophistication of the quantitative analysis system software, the rationality and accuracy of the established sample deferential document have become the most important guarantee to the reliability of sample quantitative analysis. This work is an important technical subject in China Petroleum Reservoir Research. Through two years of research and experimental work, the EDS quantitative analysis method for petroleum geology and reservoir research has been established, and referential documents for five mineral (silicate, etc.) specimen standards have been compiled. Closely combining the shape characters and compositional characters of the minerals together and applying them into reservoir diagenetic research and prevention of oil formations from damage, we have obtained obvious geological effects. [ABSTRACT FROM AUTHOR]