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This research develops two models to consider retailer sales promotion and manufacturer trade promotion under demand uncertainty. The objective of the first model is to determine the retailer’s optimal promotional effort and order quantity while maximizing the retailer’s profit under exogenous trade promotion. The second model extends the first to consider the manufacturer’s endogenous trade promotion decisions. For these models, three different trade promotion policies (off-invoice, scan-back, unsold-discount) have been compared to identify the policy that can increase the manufacturer’s and the retailer’s profits. For the model with exogenous trade promotion, the retailer’s promotional effort level, order quantity, and profit are highest under the off-invoice trade promotion policy. With respect to the manufacturer’s endogenous trade promotion decisions, the retailer’s promotional effort level, order quantity, and profit, and the manufacturer’s profit are higher under the off-invoice policy than under the scan-backs policy. When comparing the three different trade promotion policies, we also find that the wholesale price is a key factor that influences a manufacturer’s profit. Our research sheds light on the importance of trade promotion policy in supply chain management.

A modeling of the large amplitude free vibration of pretwisted hybrid composite blades is studied by considering the laminated structure which is composed of carbon nanotube reinforced composite (CNTRC) layers and matrix cracked fiber reinforced composite (FRC) layers. Two assumptions are made to facilitate this vibration study of hybrid nanocomposite: (1) CNTs are distributed across the layer thickness uniformly or functionally graded, and (2) the parallel slit matrix cracks disperse in the matrix homogeneously. Based on the theory of differential geometry, a novel shell model for pretwisted hybrid nanocomposites blade is developed. The von Karman strains are adopted to capture the geometrically nonlinear behaviors of blades. The established governing equations are solved accurately and efficiently via the IMLS-Ritz method. The proposed numerical model is verified by making comparison studies and then the influence of crack density, pretwisted angle, CNT distribution and volume fraction, aspect ratio, width-to-thickness ratio, and ply-angle on the large amplitude vibration characteristics of matrix cracked pretwisted hybrid composite blade are scrutinized systematically. The present study serves as a useful benchmark to researchers who intend do further research in this topic.

Although carbon nanotube (CNT) is an excellent additive in geopolymer, the effect of its chemical bonding at interfaces is not well understood. This paper explores the effects of interfacial bonding on the structure, dynamics and mechanical properties of CNT-geopolymer nanocomposites via molecular dynamics simulations. Our findings from the structural analysis reveal that the interfacial bonding decreases the thickness of the “interfacial van der waals (vdW) excluded volume” and interphase (inner) region, and condenses the interfacial structure. Remarkably, it is found that the interfacial bonding provides a new “restrictive mechanism” limiting the diffusion of components in the geopolymer matrix. A dynamical heterogeneous character is found as the atom mobility of the inner region is slower than that of the outer region. Furthermore, the pull-out test reveals about 15 times increase in the interfacial shear strength of CNT-geopolymer nanocomposite with 10.0% interfacial bonding concentration, which is beneficial for the enhancement of its mechanical properties and hinders crack formation under tensile loading. The tensile test reveals about 60% and 80% increase in the nanocomposite’s Young’s modulus and tensile strength, respectively. This study provides, for the first time, valuable insight into the role of the interfacial bonding on the performance of CNT-geopolymer nanocomposites.

Several dehydroabietylamine derivatives containing heterocyclic moieties such as thiophene and pyrazine ring were successfully synthesized. The antiproliferative activities of these thiophene-based Schiff-bases, thiophene amides, and pyrazine amides were investigated in vitro against Hela (cervix), MCF-7 (breast), A549 (lung), HepG2 (liver), and HUVEC (umbilical vein) cells by MTT assay. The toxicity of L1−L10 (IC50 = 5.92− >100 μM) was lower than L0 (1.27 μM) and DOX (4.40 μM) in every case. Compound L1 had higher anti-HepG2 (0.66 μM), anti-MCF-7 (5.33 μM), and anti-A549 (2.11 μM) and compound L3 had higher anti-HepG2 (1.63 μM) and anti-MCF-7 (2.65 μM) activities. Both of these compounds were recognized with high efficiency in apoptosis induction in HepG2 cells and intercalated binding modes with DNA. Moreover, with average IC50 values of 0.66 and 5.98 μM, L1 was nine times more effective at suppressing cultured HepG2 cells viability than normal cells (SI = 9). The relative tumor proliferation rate (T/C) was 38.6%, the tumor inhibition rate was up to 61.2%, which indicated that L1 had no significant toxicity but high anti-HepG2 activity in vivo. Thus, it may be a potential antiproliferation drug with nontoxic side effects.

This study evaluates the mechanical performance and efficiency of epoxy-coated CFRP-reinforcements laminates in different recycled concrete beam configurations as well as conventional concrete beam. Our results revealed that the epoxy-coated CFRP laminate is a potential internal reinforcement in recycled concrete beams with significant improvement in ductility, load-carrying capacity, fracture toughness and fracture energy of both recycled and conventional. The improved efficiencies of the reinforced recycled concrete beams is attributed to the high tensile strength of the epoxy-coated CFRP laminates, large contact surface area with the concrete, and improved bonding of the recycled concrete with the epoxy-coated CFRP laminate as a result of better aggregate interlock and improved interfacial transition zone of the recycled concrete. Our research also demonstrated that digital image correlation (DIC) can be utilized to capture full strain evolution as well as fracture propagation during experimental tests. In addition, pilot tests are needed to improve confidence towards their usage in on-site construction as well as lightweight modular and pre-fabricated concrete structures. High-quality recycling schemes should be put in place to encourage application of recycled coarse aggregates from construction and demolition wastes and avoid their landfill disposal.

Understanding dislocation multiplication, interactions, and hence crystal plasticity has been a long-standing challenge of major scientific significance. Combining atomistic enriched constitutive law with continuum finite element formulation, we developed a multiscale framework to capture geometrically-compatible dislocation patterns in Body Centered Cubic (BCC) single crystals. This dislocation pattern dynamics framework was successfully applied to study crystal plasticity in Face Centered Cubic (FCC) crystals before, coined as the Multiscale Crystal Defect Dynamics (MCDD) method. Inheriting from MCDD method, we now established a multiscale dislocation pattern dynamics model for BCC crytals with the following novelties: (1) Comparing with molecular dynamics approach, MCDD can predict crystal plasticity in BCC crystals in a more efficient way and in larger scale; (2) MCDD can capture the geometrically-compatible dislocation pattern distribution and evolution in BCC crystals, and (3) MCDD can capture the size effect of crystal plasticity in single BCC crystals at nanoscale, or to simulate size-dependent plasticity in BCC single crystals. In particular, we have successfully simulated crystal plasticity in a BCC crystal at the sub-micron scale by using a serial computing code in a desktop environment.

The influence of high temperature (1000 °C) on the microstructure and phase transformation of graphene-cement composites was investigated experimentally. The results exhibited that Graphene brought a significant influence not only on the phase transformation of hydration products, but also on the microstructure of cemented crystals. The phase transformation of hydration products was studied through X-ray diffraction (XRD) and Fourier Transform Infrared Spectrum (FTIR) under different temperature, from which we captured the phase transformation temperature of ettringite, portlandite and calcium carbonate in graphene-cement composites. The influence of graphene on the morphology of cement at various temperatures was observed through scanning electron microscopic (SEM), showing that crystal particles crystalized around graphene had regular shape and ordered arrangement at certain temperature. The morphology of hydration products could also regularly crystalize with the increase of heating temperature. The initiation and propagation of cracks in cement matrix were also investigated at high temperature.

Over the past decades, a vast number of theories for numerical modeling of laminated composite plates and shells has been developed by various researchers and for diverse reasons. Three-dimensional elasticity theory , equivalent single-layer theories, zig-zag theories and layerwise theories are notable examples. In general, computing 3D elasticity solutions require huge computational time, the ESL theories cannot furnish satisfying results for thick laminates or laminates with distinct properties between layers, and the zig-zag theories cannot directly obtain the transverse stress fields from the constitutive model. The layerwise theory treats each layer individually and C z 0 continuity is satisfied from the beginning; therefore, it yields results comparable to 3D elasticity solutions. These attributes and advantages have driven the prosperity of layerwise theories for analysis of composite laminates and structures. The main aim of this review is to provide the recent development of layerwise theories, their numerical implementation, and application in the analysis of composite laminated structures . The main conclusions and possible future research trends are presented. We expect this review will provide a clear picture of layerwise theory for modeling of composite laminated structures and serve as a useful resource and guide to researchers who intend to extend their work into these research areas.

We investigate chemical reactions, mechanical behaviors and interfacial sliding of calcium silicate hydrates (C S H) incorporating graphene nanosheet (GNS) and graphene oxide (GO) containing epoxides (GO-Oo) and hydroxyls (GO-OH) through molecular dynamics simulation. Structural analysis reveals that chemical reactions occur at the interface between GO and C S H matrices because the alkaline environment in C S H provides Ca2+ coordination and hydrogen bonds with GO. The Young's modulus and strength of C S H are enhanced by 52.6% and 23.3% with the incorporation of GO-OH while an increase of 31.6% and 17.5% in Young's modulus and strength is achieved by incorporating GO-Oo, attributed to high interfacial interaction energy and mechanical interlocking. However, GNS can hardly enhance the mechanical properties of C S H because its 2D surface has no interlocking with the matrix. The pull-out test reveals that mechanical interlocking plays a decisive role in the enhancement of the interfacial shear strength. During the pull-out process, functional groups are exfoliated from GO, which is harmful to its reinforcing ability. This study provides, for the first time, valuable insight into interfacial reaction mechanisms and working mechanisms of GNS/GO in realistic C S H structure.

Since the Silk Road Economic Belt initiative was put forward in 2013, the industrial structure of Xinjiang has become increasingly rationalized, and Xinjiang’s economic development has entered a stage of rapid development. Based on the Solow residual value method, this paper uses the gray correlation model to estimate the elastic coefficient of capital and labor input and calculates the contribution rate of technological progress in 25 industrial sectors in Xinjiang. The research results show that more than 50% of the industrial sector in Xinjiang contributes more than 50% to technological progress, and Xinjiang’s economy has entered a period of intensive rapid development.

The insulation structure of transformer leads should not only meet the requirements of temperature rise and reliable mechanical strength during long full load operation, but also withstand various Insulation Withstanding Test. Therefore, the insulation structure design of power transformer leads is one of the important technical problems in the insulation structure design of EHV power transformer. In order to design the insulation of a lead connection, it is necessary to determine the required insulation distance and insulation structure between the leads and the ground components according to the electric field calculation. This paper introduce the lead insulation structure of a 750kV single-phase auto-transformer, calculate the electric field of the 750kV leads by the finite element electromagnetic field simulation software. In this paper, the insulation structure of the high voltage and medium voltage leads of the transformer is calculated in detail, it shows that reasonable shielding measures and separated the oil gap can effectively reduce the field strength of the leads, and it increase the insulation strength and reliability of the leads, and provide guidance for the insulation structure design of EHV power transformer.

Drug delivery to the inner ear by nanomedicine strategies has emerged as an effective therapeutic approach for the management of inner ear diseases including hearing and balance disorders. It is well accepted that substance enters the perilymph from the middle ear through the round window membrane (RWM), but the passage through the oval window (OW) has long been neglected. Up to now, researchers still know little about the pathway via which nanoparticles (NPs) enter the inner ear or how they reach the inner ear following local applications. Herein, we engineered fluorescence traceable chitosan (CS) NPs, investigated the NP distribution within cochlear and vestibular organs, and assessed the availability of RWM and OW pathways to NP transport. Intriguingly, there were high levels of CS NPs in vestibular hair cells, dark cells and supporting cells, but negligible ones in cochlear hair cells and epithelial cells after intratympanic administration. However, the NPs were visualized in two cell models, L929 and HEI-OC1 cell lines, and in the hair cells of cochlear explants after co-incubation in vitro. These combined studies implied that CS NPs might enter the vestibule directly through the OW and then preferentially accumulated in the cells of vestibular organs. Thus, in vivo studies were carried out and clearly revealed that CS NPs entered the inner ear through both the RWM and OW, but the latter played a governing role in delivering NPs to the vestibule with vivid fluorescence signals in the thin bone of the stapes footplate. Overall, these findings firstly suggested that the OW, as a royal gate, afforded a convenient access to facilitate CS NPs transport into inner ear, casting a new light on future clinical applications of NPs in the effective treatment of vestibular disorders by minimizing the risk of hearing loss associated with cochlear hair cell pathology.

Cavitation and crazing in thermosetting polymers can be sophisticatedly designed for valuable applications in optics, electronics, and biotechnology. It is a great challenge for numerical study to describe the formations of cavity and fibrils in polymer composite due to the complicated interfacial interaction. To explore this challenging task, we exploit a two-phase coarse-grained framework which serves as an efficient atomistic level-consistent approach to expose and predict the transition between cavitation and crazing in a polymeric system. The coarse-grained framework is utilized to transmit the information between single phase and interface in polymer composite, and the learning tasks of force field are fulfilled through parameterization of mechanical performances and structural characterizations. We elaborate on the intrinsic characteristics of the cavitation-crazing transition in diamond nanothread- (DNT-) reinforced polymethyl methacrylate composites, in which DNT plays a specific role of nanomodulator to tune the cavity volume ratio. The transition from cavitation to crazing can be induced through a novel dissipative mechanism of opening an interlocked network, in which case the DNT is stretched to the aligned fibrils and links crazing tightly by interfacial adhesion. The designed computational framework can broaden the scope of theoretical tools for providing better insights into the microstructure design of polymer composites.

Brucea javanica oil (BJO) is a traditional herbal medicine in China for the effective treatment of various diseases due to multifaceted activities. As the most common formulation, BJO emulsion (BJOE) has been employed to treat carcinomas in clinical practice for many years. Herein, we fabricated a solid self-microemulsifying drug delivery system (S-SMEDDS) of BJO and assessed its antitumor effects on cancer cell lines A549 and DU145. The shape of BJO-loaded S-SMEDDS (BJOS) was approximately spherical and the nanosuspension was stable. Since the proliferation of A549 and DU145 cells was significantly inhibited by BJOS dose-dependently compared to that by BJOE, BJOS had enhanced anticancer effects. Given a lower IC50, DU145 cells were more sensitive to BJOS than A549 cells. Besides, flow cytometry showed that A549 and DU145 cell cycles were arrested in the G0/G1 phase, and the transwell assay demonstrated that their invasion ability decreased apparently after 24 h of exposure to BJOS. In conclusion, BJOS was a promising formulation for improving the treatment of lung cancer and prostate cancer.

Although thin on the order of several to tens of millimeters, sheet flows normally comprise a lower pick-up sub-layer and an upper contact-load sub-layer, separated at the bed level (z = 0). The time-averaged concentration profile in the pick-up sub-layer shows a ‘convex upward’ curvature, but ‘concave upward’ shape characterizes the time-averaged concentration profile in the contact-load sub-layer. The time-dependent concentration in the contact-load sub-layer is approximately in-phase with the free stream flow velocity, whereas it is nearly in anti-phase with the free stream flow velocity in the pick-up sub-layer. Two distinct analytical expressions of the time-averaged concentration profiles for the respective sub-layers are proposed. The expressions are validated with detailed observation datasets collected in the Groβer Wellenkanal (GWK) prototype wave flume in Hannover, Germany. The agreement between the predicted and the measured values is excellent. Interparticle collisions in the pick-up sub-layer and convective lifting processes associated with vortex shedding in the contact-load sub-layer are considered responsible for the opposite curvatures and in-phase/anti-phase concentration variations. Both transitional boundary and reference concentration are also elaborated.

The use of meshfree and particle methods in the field of bioengineering and biomechanics has significantly increased. This may be attributed to their unique abilities to overcome most of the inherent limitations of mesh-based methods in dealing with problems involving large deformation and complex geometry that are common in bioengineering and computational biomechanics in particular. This review article is intended to identify, highlight and summarize research works on topics that are of substantial interest in the field of computational biomechanics in which meshfree or particle methods have been employed for analysis, simulation or/and modeling of biological systems such as soft matters, cells, biological soft and hard tissues and organs. We also anticipate that this review will serve as a useful resource and guide to researchers who intend to extend their work into these research areas. This review article includes 333 references.

In this work, a novel fluorescent sensor (quercetin-Pluronic-F127 nano-micelles) was prepared by the facile self-assembly method with natural quercetin (Qc) and Pluronic-F127 (F127). Qc-F127 nano-micelles were characterized by TEM which indicated that Qc have successfully entered into the amphiphilic micelle. The nano micelles with sizes of 25 to 40 nm showed a strong green fluorescence (FL). The sensor exhibits high sensitivity and selectivity towards Cu2+ with a linear range of 5 × 10−8–4 × 10−6 mol L−1, the detection limit of 1 × 10−8 mol L −1. Moreover, the Qc-F127 nano-micelles can be used to detect Cu2+ in vitro due to their good biocompatibility. Besides Cu2+ sensing, when Cysteine (Cys) were added, the FL intensity of Qc-F127-Cu(II) system could be restored due to the chelation interactions between Cu2+ ions and the sulfydryl and amino groups of Cys. So, Qc-F127-Cu(II) system can used to detect Cys, and the linear range and the limit of detection of the Qc-F127-Cu2+ system were 3 × 10−7–3.5 × 10−5 mol L−1 and 6 × 10−8 mol L −1. Moreover, Qc-F127-Cu(II) has been used for imaging of Cys in cells, which demonstrates its values for potential application in biological systems.

One-dimensional diamond nanothread (DNT) has drawn intensive research interests and become a promising candidate for nanocomposites reinforcement. This paper explores the mechanical properties of DNT reinforced poly (methyl methacrylate) (PMMA) composite under tensile deformation via molecular dynamics simulation. The study shows that the Young's modulus and yielding stress of PMMA composite are enhanced by 85% and 15% with the incorporation of DNT. Remarkably, DNT which is a hydrogenated carbon nanotube (CNT) is proved to strengthen PMMA composite more effectively than CNT for a similar structure. The outstanding strengthening of DNT is attributed to interfacial interaction and mechanical interlocking between DNT and PMMA matrix. A pull-out simulation is conducted to examine the interfacial shear strength of DNT-PMMA interface and comparison studies are made with that of CNT-PMMA interface. The results reveal that DNT has higher load transference within PMMA composite than CNT, by presenting 34% above CNT in interfacial shear strength. It is also demonstrated that DNT morphology can significantly affect the interfacial interaction and mechanical interlocking with PMMA matrix, leading to distinguished reinforcement efficiency for PMMA composite. These findings will shed light to DNT application in nanocomposites and provide an important insight into reinforcing mechanism.

This paper presents the mathematical modeling of the nonlinear vibration behavior of a hybrid laminated plate composed of carbon nanotube reinforced functionally graded (CNTR-FG) layers and conventional fiber reinforced composite (FRC) layers. Three type symmetric distributions of single walled carbon nanotubes (SWCNTs) through the thickness of layers are considered. The cracks are modeled as aligned slit cracks across the ply thickness and transverse to the laminate plane. The distribution of cracks is assumed to be statistically homogeneous corresponding to an average crack density. The obtained partial differential equations are solved by the element-free kp-Ritz method, and the iteration process is dealt with using the linearized updated mode method. Detailed parametric studies are conducted investigate the effects of matrix crack density, CNTs distributions, CNT volume fraction, plate aspect ratio and plate length-to-thickness ratio, boundary conditions and number of layers on the frequency-amplitude responses of hybrid laminated plates containing CNTR-FG layers.

Background: Crocus sativus L. (saffron) is a scarce plant that has been used as food flavoring agent, coloring agent, and traditional herbal medicine. Methods: The bioactivity of exopolysaccharide (EPS) extracted from an endophytic fungus of C. sativus was examined for the first time by antioxidative, antitumor, and antibacterial assays. The extraction conditions for EPS were optimized by combining the response surface methodology with Box-Behnken design. Results: EPS exhibited excellent scavenging activities against 1,1-diphenyl-2-picrylhydrazyl, hydroxyl and superoxide anion radicals, and moderate cytotoxicities against K562, A549, HL-60, and HeLa cells. The optimum extraction conditions for EPS were as follows: precipitation time of 16 h, precipitation temperature of 3.7°C, pH 7.2, and ratio of ethanol to fermented broth of 5:1 (L/L). Under the optimized conditions, the yield of EPS reached 162 ± 6 μg/L which was close to the predicted one (165 μg/L). Moreover, high-performance liquid chromatography of monosaccharide composition showed that EPS comprised mannose, glucose, galactose xylose, and arabinose in a molar ratio of 25.6:16.5:1.0:3.8:5.4. Conclusion: EPS may be an eligible substitute for C. sativus and a potential bioactive source applicable to pharmaceutical and food industries. SUMMARY Exopolysaccharide (EPS) from endophytic fungus of Crocus sativus was studied for the first timeEPS extraction was optimized by combining response surface methodology with Box-Behnken designMonosaccharide composition and EPS structure were identified by high-performance liquid chromatography and Fourier-transform infrared spectroscopy. Abbreviations used: EPS: Exopolysaccharide, RSM: Response surface methodology, BBD: Box-Behnken design, DPPH: 1,1-diphenyl-2-picrylhydrazyl, VC: Ascorbic acid, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, LB: Luria Bertani, DMSO: dimethyl sulfoxide, PMP: 1-phenyl-3-methyl-5-pyrazolone, FT-IR: Fourier transform-infrared, HPLC: High-performance liquid chromatography, 3D: Three-dimensional, 2D: Two-Dimensional.

The day/night band (DNB) of the Visible Infrared Imaging Radiometer Suite can not only identify surface characteristics when illuminated by moonlight, but can also detect night-time radiation from ...

In this paper, we develop quercetin-coated Fe3O4 nanoparticles (QMNPS) as a sensor for the detection and removal of Pb2+ and Cu2+ based on low-field NMR. QMNPS were characterized by TEM, FTIR and XRD. The NMR sensor showed high selectivity toward Pb2+ or Cu2+. The standard curves for ΔT2-ion concentration showed good correlations, i.e., R2 = 0.9912 for Pb2+ and 0.9983 for Cu2+; the linear ranges and the limits of detection were 4.8 × 10−6–1 × 10−4 mol L−1 and 1.6 × 10−6 mol L−1 for Pb2+, and 5.0 × 10−6–1 × 10−4 mol L−1 and 2.0 × 10−6 mol L−1 for Cu2+, respectively. The calculated maximum adsorption capacity was about 71 mg for Cu2+ and 68 mg for Pb2+ per gram of QMMP, which was superior to the results of some previous reports. The detection and removal of Pb2+ or Cu2+ was based on the coordination reaction between the NMR sensor of QMNPs and Pb2+ or Cu2+, which led to the aggregation of QMNPs. As a result, the proposed NMR sensor was successfully applied for the determination and removal of Pb2+ and Cu2+ in contaminated water and urine samples with excellent recoveries and high adsorbent capacities.

A first known study on the mechanical behavior of laminated CNT-reinforced quadrilateral composite plates due to a sudden transverse dynamic load is performed. In this study, a moderately thick plate is considered; therefore, the first-order shear deformation theory (FSDT) is employed in the formulation. The numerical analysis of the problem is carried out using the IMLS-Ritz method. The Newmark- β method is employed for the numerical time integration of the dynamic problem. The Mori-Tanaka approach is adopted for predicting the properties of CNT-composites. The numerical stabilities and accuracies of the IMLS-Ritz method are examined. The convergence properties are illustrated through solving an isotropic square plate and a laminated CNT-composite quadrilateral plate by varying their node numbers and support sizes. A comprehensive parametric study has been carried out to examine the dynamic behavior of symmetric and asymmetric CNT-composite plates.

A precise first attempt is performed to quantify the biomechanical properties of human erythrocyte membrane subjects to extreme temperature and loading conditions. An improved three-dimensional (3D) atomistic–continuum model based on the Cauchy–Born rule is proposed to investigate the elastic properties and biomechanical responses of the erythrocyte membrane. A membrane rigidity model is developed to estimate the membrane elastic properties over an extreme temperature range. Our computational results reveal that the membrane is able to sustain large strains up to a certain limit; beyond which, mechanically induced hemolysis may occur as exponential stress increment, fluctuations and multiple peaks were observed in the stress–strain curves. Additionally, we found that the overall deformability of the erythrocyte membrane significantly decreases as temperature increases. It is concluded that the observed increase in membrane rigidity may be attributed to the denaturation, structural remodeling and cross-linking of membrane cytoskeletal proteins.

The properties of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and penetration enhancers play a deciding role in the inner ear drug delivery of NPs across the round window membrane (RWM). Thus, PLGA nano-based systems with a variety of particle sizes and surface chemistries and those combined with cell-penetrating peptides (CPPs) as penetration enhancers were devised to explore their impact on the cochlear drug delivery in vivo. First, we demonstrated that the properties of NPs dictated the extent of NP cochlear entry by near-infrared fluorescence imaging. NPs with the sizes of 150 and 300nm had faster entry than that of 80nm NPs. At 0.5h, among the NPs unmodified and modified with chitosan (CS), poloxamer 407 (P407) and methoxy polyethylene glycol, CS-PLGA-NPs (positive surface charge) carried payload to the cochlea fastest, whereas P407-PLGA-NPs (surface hydrophilicity) showed the greatest distribution in the cochlea at 24h. Compared to other CPPs (TAT, penetratin and poly(arginine)8), low molecular weight protamine (LMWP) performed an outstanding enhanced NP cellular uptake in HEI-OC1 cells and cochlear entry. More importantly, NPs with optimized properties and CPPs may be combined to improve RWM penetration. For the first time, we confirmed that the combination of P407-PLGA-NPs (mean diameter: 100-200nm) and LMWP provided a synergistic enhancement in NP entry to the organ of Corti and stria vascularis without inducing pathological alteration of cochlear tissues and RWM. Taken together, we propose an effective PLGA nano-based strategy for enhanced drug delivery to the inner ear tissues that combines hydrophilic molecule-modified NPs and CPPs, ultimately opening an avenue for superior inner ear therapy.

We examine the aeroelastic behavior of a cylindrical nanocomposite (i.e. CNT-reinforced composite) shell in a supersonic airflow under thermal environments. Meanwhile, using piezoelectric materials, active flutter control of the cylindrical nanocomposite shell is conducted. Reddy’s high-order shear deformation theory is applied in the structural modeling, and the displacement fields of piezoelectric patches are derived according to the geometrical deformation relationship. The partial differential equation of motion is formulated by way of Hamilton’s principle and then is discretized by the assumed mode method. The active controller is designed by the displacement feedback and linear quadratic regular (LQR) methods. The aerothermoelastic properties of the cylindrical shell are analyzed using the frequency-domain method. The flutter bounds of the cylindrical shell are computed using the third-order shear deformation theory (TSDT), and the first-order shear deformation theory (FSDT) is compared in order to verify the necessity of the high-order shear deformation theory in the vibration analysis of thick nanocomposite structures. The influences of temperature change, CNT distribution and CNT volume fraction on the aeroelastic stability of the nanocomposite cylindrical shell are investigated. The active flutter control effects of different control methods are performed. The influence of thickness of the cylindrical shell on the flutter control effects is examined.

Due to their valuable and unique properties, graphene sheets (GSs) have attracted increasing attention in recent years. This paper presents the mathematical modeling of the nonlinear vibration behavior of GSs using classic plate theory and nonlocal elasticity theory which accounts for the size effect. The numerical solutions are obtained through the element-free kp-Ritz method. The iteration process is dealt with using the linearized updated mode method. The transformation method is used to impose the boundary conditions. The published results are used to verify the correctness of the present nonlocal element-free kp-Ritz method. The effects of boundary conditions, side length, aspect ratio and nonlocal parameters on the frequency–amplitude response are examined.

This paper presents the first known mechanical behavior of laminated CNT-reinforced composite skew plates subjected to a transverse sudden dynamic load. The plate is composed of multilayers of nanocomposite reinforced with single-walled carbon nanotubes (SWCNTs). The problem is formulated using the first-order shear deformation theory (FSDT), and solution to the problem is obtained through the element-free IMLS-Ritz method. The elastodynamic behavior is furnished by employing the Newmark-β method. Material properties of CNT-reinforced composites are predicted through the Mori–Tanaka approach. The stability and precision of the IMLS-Ritz method are validated by convergence and comparison studies. The effects of skew angles, width-to-thickness ratio, CNT-volume fraction, CNT-distribution along the layer thickness, CNT-fiber orientation and boundary conditions on the elastodynamic responses of laminated CNT-reinforced composite skew plates are examined.

Additive manufacturing (AM) or 3D printing has been hailed as the third industrial revolution as it has caused a paradigm shift in the way objects have been manufactured. Conventionally, converting a raw material to a fully finished and assembled, usable product comprises several steps which can be eliminated by using this process as functional products can be created directly from the raw material at a fraction of the time originally consumed. Thus, AM has found applications in several sectors including automotive, aerospace, printed electronics, and healthcare. AM is increasingly being used in the healthcare sector, given its potential to fabricate patient-specific customized implants with required accuracy and precision. Implantable heart valves, rib cages, and bones are some of the examples where AM technologies are used. A vast variety of materials including ceramics, metals, polymers, and composites have been processed to fabricate intricate implants using 3D printing. The applications of AM in dentistry include maxillofacial implants, dentures, and other prosthetic aids. It may also be used in surgical training and planning, as anatomical models can be created at ease using AM. This article gives an overview of the AM process and reviews in detail the applications of 3D printing in dentistry. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2058-2064, 2018.

Graphene sheets have wide application, in which the integration of multiple disparate fields for the realization of expanded functionalities is of great significance. This study investigates the vibration behavior of quadrilateral single-layered graphene sheets (SLGSs) in a magnetic field using classic plate theory and incorporating nonlocal elasticity theory, concerning the small scale effect. The element-free kp-Ritz method is employed to perform the numerical simulation. The efficiency of the proposed numerical tool is verified by published results. The effect of nonlocal parameters, skew angles, magnetic parameters and boundary conditions on the vibration behavior of parallelogram SLGSs is studied. The results show that skew angles and the magnetic field help increase the fundamental frequencies of SLGSs, which indicates the potential application of SLGSs as highly sensitive mass detectors. Moreover, 14 different quadrilateral SLGSs, with different nonlocal parameters and magnetic parameters for different boundary conditions, are simulated.

To the best of our knowledge, the available literature investigating the impact analysis of functionally graded carbon nanotube reinforced composite (CNTRC) plates is very limited and missing in the case of utilizing any of the element-free methods. In this paper, a novel element-free IMLS-Ritz model in association with Reddy’s higher-order shear deformation theory is presented to study the impact analysis of CNTRC plates with both uniform and functionally graded carbon nanotubes (CNTs) distributions. The modified non-linear Hertz contact law is used to define the contact force between the CNTRC target plates and the spherical impactor during the impact duration. Newmark time integration method is employed to identify the dynamic response of the CNTRC plates and the impactor displacement. Two Mori–Tanaka methods are utilized to calculate the effective material properties of the composites reinforced with randomly oriented or aligned straight CNTs. The current approach accuracy is validated with the available open literature results showing a clear agreement. Detailed parametric studies are performed to study the effects of CNTs distributions, plate’s width-to-thickness ratio, impactor’s initial velocity, impactor’s radius and CNTs volume fraction on the results. Furthermore, a comparison between the results obtained by the two Mori-Tanka methods is presented.

The structural stability and anti-deforming capability of borophene and graphene-filled calcium silicate (C 2 S) for cement-based materials are studied by employing molecular dynamic simulations. By analyzing and comparing their various potential energies, it is found that the introduction of borophene or graphene into C 2 S can effectively improve its structural stability, make the complex nanosheets cling tightly together, and enhance the ability to resist deformation of the configuration at high temperature, especially for borophene-filled calcium silicate (C 2 S-B). Structural analyses on the above complexes at a high compression strain (14.06%) and a high temperature (1000 K) indicate that the graphene-filled calcium silicate (C 2 S-G) has the best pressure resistance and the C 2 S-B has the greatest high temperature tolerance, while C 2 S is always the worst. The results indicate that filling graphene and borophene in calcium silicate can significantly improve the structural stability and enhance the resistance to compressive and high temperature.

In the hydration process of a cementitious matrix, considerable interactive physical and chemical changes take place inside the material that affect both the composition and morphology of cement paste during its early stages. These changes are properly considered within a multiscale model that comprises length-scale integration and gives access to the effective properties via upscaling. In this paper, the kinetics laws of the induction period, nucleation, and growth-controlled and diffusion-controlled hydration are considered, and the evolutions of volume fractions of clinker phases and various hydration products with respect to the hydration degrees are simulated. Based on the microstructural evolution of cement hydration, the properties of cement paste are estimated with a combination of self-consistent and Mori–Tanaka schemes, and the mechanical properties of carbon nanotube-reinforced cement-based composites on the macroscale are then predicted with a meshless method on the basis of the moving least-squares approximation. Finally, the accuracy and efficiency of the proposed model are verified by comparisons with experiments and finite element model simulations.

Experimental studies are carried out to examine the microstructure and mechanical performance of carbon nanotube (CNT) reinforced cementitious composites at elevated temperatures (25 °C, 200 °C, 400 °C and 600 °C). Two different contents (0.1% and 0.2% by weight of cement) of CNT are added to cement paste. X-ray powder diffraction (XRD) results show that CNT does not improve or impede the hydration of cement minerals at room temperature, while at higher temperatures the further hydration process caused by high-pressure steam is impeded by CNT. The morphology observed by scanning electron microscopy (SEM) indicates that the bridging effect of CNT can be maintained below 400 °C, while CNT is mostly spalled with the matrix on the walls of pores and gaps at 600 °C. The residual flexural and compressive strength are measured. The reinforcing effect of CNT is most obvious at 400 °C, which is due to the potential of CNT as channels for releasing high-pressure steam.

The buckling behavior of nanocomposite plates of polygonal planform under in-plane loads is examined. The plate under consideration is reinforced by single-walled carbon nanotubes (CNTs). The governing eigenvalue equation to this problem is derived based on the first-order shear deformation plate theory (FSDT) with a set of element-free shape functions in approximating the two-dimensional displacement fields. To solve this eigenvalue equation, the element-free IMLS-Ritz method is employed to furnish the buckling solution. The convergence of the solution for the CNT-reinforced composite plates is examined. Comparison study is further carried out to validate the accuracy of the solution. A parametric study is performed by varying the CNT volume fraction, CNT distribution, plate thickness-to-apothem ratio and boundary conditions. This first known buckling solution may serve as benchmarks for future research.

A first attempt to investigate bending and vibration behaviors of carbon nanotube (CNT) reinforced functionally graded composite skew plates using the isogeometric analysis is performed. The formulation of the plate is based on Reddy’s higher order shear deformation theory (HSDT). The effect of CNT orientation angle on the mechanical behavior of CNT-reinforced composite plates with varying skew angles is investigated. The optimum fiber orientations for CNT-reinforced composite skew plates with simply supported, clamped and cantilevered boundary conditions are found. It is shown that selecting the correct fiber orientation angle is of crucial importance in obtaining the desired static and dynamic responses of CNT-reinforced composite skew plates.

A comprehensive study on elastodynamic behavior of regular polygonal carbon nanotube (CNT) reinforced functionally graded composite plates subjected to a sudden transverse dynamic load is presented in this paper. This analysis uses as its base the first-order shear deformation theory (FSDT) and the element-free IMLS-Ritz method, to conduct a numerical simulation. A numerical time integration for the dynamic problems is performed using the Newmark-β method. Convergence studies are carried out for an isotropic square plate with different support sizes and different numbers of nodes. Parametric studies are further carried out to investigate the effect of four special regular polygons with different CNT volume fractions, CNT distribution types, plate apothem-to-thickness ratios and boundary conditions on the dynamic behaviors of regular polygonal CNT-reinforced composite plates.

This paper presents a first know study of the effect of orientation angle of carbon nanotubes (CNTs), embedded in a single-ply polymer-based CNT-reinforced composite, on buckling behavior of skew plates using an isogeometric analysis. The plate model is based on Reddy’s higher-order shear deformation theory (HSDT). Four in-plane loading conditions together with simply supported and cantilevered boundary conditions have been considered. The optimum CNT fiber orientations for CNT-reinforced composite rhombic plates with varying skew angles and boundary conditions are presented. Moreover, the effect of width-to-thickness ratio on optimum CNT orientation is explored. The results show that the efficiency of the skew plate structures can be significantly improved by simply placing the CNTs in the correct orientation.

To date, the literature investigating the active vibration control of carbon nanotube reinforced composite (CNTRC) plates with piezoelectric layers is limited. Furthermore, studying this particular problem utilizing any of the element-free methods is missing. This paper presents a novel element-free IMLS-Ritz model based on Reddy’s higher-order shear deformation theory to study this issue. Four carbon nanotubes (CNTs) distributions are considered including both uniform and functionally graded types. For all these distributions, the effective material properties of the CNTRC plates are calculated by the Mori–Tanaka method. A conversion study has been performed to select the appropriate values of nodes number and scaling factor that give accurate results compared to the literature. New detailed natural frequency results have been presented for various CNTs volume fractions, CNTs distribution types, dimensions ratios and boundary conditions. Parametric studies have been carried out to show the effects of boundary conditions, CNTs volume fraction, CNTs distribution type and piezoelectric layer thickness to total plate thickness ratio on the natural frequency increment between open and closed circuit conditions. A constant velocity feedback approach is adopted for the active vibration control of the composite plates and two positions of piezoelectric sensor and actuator layers are proposed.

We theoretically study the band structure and optical conductivity of twisted bilayer graphene (TBG) near the magic angle considering the effects of lattice relaxation. We show that the optical conductivity spectrum is characterized by a series of peaks associated with the van Hove singularities in the band structure, and the peak energies evolve systematically with the twist angle. Lattice relaxation effects in TBG modify its band structure, especially the flat bands, which lead to significant shifts of the peaks in optical conductivity. These results demonstrate that spectroscopic features in the optical conductivity can serve as fingerprints for exploring the band structure, band gap and lattice relaxation in magic angle TBG as well as identifying its rotation angle., Comment: 16 pages, 5 figures, accepted by Chinese Physics B

Reinforcement learning (RL) is attracting increasing interests in autonomous driving due to its potential to solve complex classification and control problems. However, existing RL algorithms are rarely applied to real vehicles for two predominant problems: behaviours are unexplainable, and they cannot guarantee safety under new scenarios. This paper presents a safe RL algorithm, called Parallel Constrained Policy Optimization (PCPO), for two autonomous driving tasks. PCPO extends today's common actor-critic architecture to a three-component learning framework, in which three neural networks are used to approximate the policy function, value function and a newly added risk function, respectively. Meanwhile, a trust region constraint is added to allow large update steps without breaking the monotonic improvement condition. To ensure the feasibility of safety constrained problems, synchronized parallel learners are employed to explore different state spaces, which accelerates learning and policy-update. The simulations of two scenarios for autonomous vehicles confirm we can ensure safety while achieving fast learning.

Traditional intelligent product design usually focuses on functional design, aiming to generate appropriate structures that would provide required functions. Design specifications are mainly formulized into technical descriptions or values that are related to certain functional or usability requirements. In today’s global market, to in-crease user satisfaction, the appearance design of a product become vital for users to make purchasing decisions. This is particularly true of today’s consumer products such as mobile phones, digital cameras, and other electronic products. In intelligent product appearance design, design specifications are merely described as basic geometric dimensions and types of surface materials. Additionally, the aesthetic considerations and emotional needs of product appearance are seldom discussed when establishing design specifications for product appearance design. In this regard, the objective of this study is to propose a design specification representation framework for intelligent product appearance design considering both emotional and aesthetic aspects. The framework be-gins to investigate user needs by acquiring user aesthetic experience. Based on the notion of aesthetic experience, a detailed representation model of appearance design specifications is provided for satisfying user emotional and aesthetic needs. Finally, a case study of the appearance design of digital cameras is provided to demonstrate the acquisition of user needs and establishment of design specifications based on the proposed framework.

Surface dielectric barrier discharge (SDBD) plasma actuators has been widely used for enhanced aerodynamics. In this paper, several different surface conductivity and frequency configurations, i.e., high conductivity surface and low supply frequency were chosen for the SDBD plasma actuator. And an improved simulation model with fewer mesh units and better convergence was proposed in this paper. The Simulated results show that surface conductivity have a significant impact on the performance of actuators, such as electric field distribution before discharge. The effects also verified by experiments.

As a consequence of recent progression in biomedicine and nanotechnology, nanoparticle-based systems have evolved as a new method with extensive applications in responsive therapy, multimodal imaging, drug delivery and natural product separation. Meanwhile, the magnetic nanoparticulate system has aroused great interest for separation and purification because of its excellent magnetic properties. Phospholipase A2 (PLA2) is a highly expressed regulator to promote the growth of various cancers and is an ideal target to treat cancers. In this study, a novel strategy based on ligand–receptor interactions to discover novel PLA2 inhibitors was established, in which PLA2-functionalized Fe3O4@PLGA-PEG-NH2 magnetic nanoparticles were used as a supporting material combined with high-performance liquid chromatography–mass spectrometry, aiming to accelerate the discovery of novel PLA2 inhibitors from natural sources such as mangrove endophytic fungi. Under the optimized ligand fishing conditions, six target compounds were ultimately fished and identified to be cyclic peptides (1–3) and sterols (4–6), which compounds 1, 2 and 4–6 have well-documented cytotoxicities. Compound 3 exerted better inhibitory effect on A549 cells by experiment. In conclusion, PLA2-functionalized Fe3O4@PLGA-PEG-NH2 magnetic nanoparticles-based ligand fishing provided a feasible, selective and effective platform for the efficient screening and identification of antitumor components from natural products.

A geometrically nonlinear analysis of carbon nanotube reinforced functionally graded (CNTR-FG) composite laminated plates is presented. Single-walled carbon nanotubes (SWCNTs) are selected as reinforcement and the effective material properties of CNTR-FG plates are assumed to be graded through the thickness direction in each layer. The two-dimensional displacement fields of the plates are approximated by a set of meshless kernel particle functions. For the purpose of eliminating shear locking, a stabilized conforming nodal integration scheme is employed to evaluate the system bending stiffness, and the membrane and shear terms are calculated by the direct nodal integration method. Parametric studies are conducted to investigate the effect of various types of CNT distribution, CNT volume fraction, plate aspect ratio and boundary conditions on the nonlinear responses of CNTR-FG laminated plates. Moreover, the effects of the number of layers and lamination angle are also investigated.

In this paper, free vibration behavior of carbon nanotube (CNT) reinforced functionally graded thick laminated composite plates utilizing Reddy’s higher-order shear deformation theory (HSDT) is studied. To the best of authors’ knowledge, this paper is the first to incorporate HSDT with one of the element-free approaches to investigate this issue. The element-free IMLS-Ritz method is employed and four types of CNT distributions are considered. The resulting effective material properties of the CNT-reinforced composite are estimated by a detailed and straightforward Mori–Tanaka approach. The numerical results have been compared with the literature showing excellent agreement. Considering various CNT orientation angles, a parametric study showing the effects of CNT volume fraction, plate aspect ratio, plate width-to-thickness ratio and number of plate’s layers on the non-dimensional natural frequencies is investigated. Finally, the influence of boundary conditions on the sequence of the first six mode shapes for various lamination arrangements is presented.

This paper investigates the impact responses of carbon nanotube (CNT) reinforced functionally graded composite cylindrical shells. The effective material properties of the CNT-reinforced composite cylindrical shell are modeled by the extended rule of mixture. Reddy’s high-order shear deformation theory is employed in the modeling, in which thermal effects are taken into account. In order to simulate the contact load, a linearized contact law is used to obtain a linearized contact coefficient. Fourier series expansion and Laplace transforms are utilized during the solving process. The analytical expression of transverse displacement is furnished, and the impact responses of CNT-reinforced composite cylindrical shell are analyzed. From the numerical results, it is observed that the amplitude of the impact responses of FG-X CNT-reinforced composite cylindrical shell is lower than that of the shell with FG-O and UD CNT-distributions. The increase in CNT volume fraction reduces the amplitude of the impact response. Meanwhile, temperature change affects both the material properties and stiffness of the structure. It is also observed that with an increased temperature, the impact amplitude of the cylindrical shell increases.

This paper investigates the effect of in-plane forces on the vibration behavior of carbon nanotube (CNT) reinforced composite skew plates. The analysis is performed by implementing the first-order shear deformation theory (FSDT) with the element-free/mesh-free Improved Moving Least Square-Ritz (IMLS-Ritz) method for solution to the problem. Two varieties of carbon nanotube-reinforced composite skew plates, namely uniformly distributed and functionally graded reinforcement are considered. A micromechanical model is employed to estimate the material properties of CNT-reinforced composite plates. Comparison studies are implemented to validate the accuracy of the proposed method. The frequency parameters and mode shapes for the skew plates are presented. A detailed parametric study is carried out to reveal many complicated effect on the frequency parameters of the plate. These effects include in-plane stress ratio, boundary conditions, CNT-volume fraction and geometric size. The obtained results will be references of future research and corresponding engineering project.

The mechanical and damping properties of CNT-reinforced cementitious composite structures were experimentally examined. In the experiments, an aromatic modified polyethylene glycol ether named TNWDIS and polyvinylpyrrolidone (PVP) were used to disperse CNTs, which were ultra-effective and compatible with cement hydrates. The growth of cement hydrates on the CNT surface was observed by Scanning Electron Microscopy (SEM) and identified by Energy Dispersive Spectrometry (EDS). X-ray Powder Diffraction (XRD) analysis suggested that the mechanism by which the CNTs and cement hydrates were combined was a physical process. The compressive and flexural strengths of CNT/cement composites were improved by 17.3 and 16.3%, respectively, through the addition of 0.1 wt.% CNTs dispersed by PVP, while the addition of CNTs dispersed by TNWDIS led to a very limited improvement in strength. In addition, the loss factor of CNT/cement matrix was measured, and 0.1 wt.% CNTs dispersed by TNWDIS improved the loss factor by 25.9%, which is nearly twice greater than the improvement caused by 0.1 wt.% CNTs dispersed by PVP.

In the construction sector, interest and exploration work within the field of carbon materials have been ongoing for many years. Although carbon fibers have already been applied to cementitious composites, carbon nanotubes (CNTs), as nanomaterials, have received widespread attention as a result of their unique multifunctional properties within the context of engineered materials. This article focuses on the research advances of CNT dispersion and CNT reinforcement on the mechanical, electrical and piezoresistive properties of cementitious composites. Sonication and surfactants, as the commonly used techniques for CNT dispersion, are introduced for CNT/CNT dispersion characterization. Four reinforcing mechanisms of CNTs in cement matrices are summarized. Various factors that work towards an effect on the mechanical, electrical and piezoresistive properties of CNTs are reported, including CNT size, CNT concentration and lattice defects on the CNT structure. In addition, the effect of CNTs on the workability, hydration process and autogenous shrinkage of cement paste are discussed.