Discharge domains regulation and dynamic processes of direct-current triboelectric nanogenerator.

Direct-current triboelectric nanogenerators arising from electrostatic breakdown can eliminate the bottleneck problem of air breakdown in conventional triboelectric nanogenerators, offering critical benefits of constant-current output, resistance to electromagnetic interference, and high output power density. Previous understanding is that its output characteristics are described by a capacitor-breakdown model or dictated by one or two discharge domains in direct-current triboelectric nanogenerators. Here, we demonstrate that the former holds only for ideal conditions and the latter cannot fully explain the dynamic process and output performance. We systematically image, define, and regulate three discharge domains in direct-current triboelectric nanogenerators, then a "cask model" is developed to bridge the cascaded-capacitor-breakdown dynamic model in ideal conditions and real outputs. Under its guidance, the output power is increased by an order of magnitude within a wide range of resistive loads. These unexplored discharge domains and optimization methods revolutionize the output performance and potential applications of direct-current triboelectric nanogenerators.

Localization on a-priori information of plane extraction.

Localization constitutes a critical challenge for autonomous mobile robots, with flattened walls serving as a fundamental reference for indoor localization. In numerous scenarios, prior knowledge of a wall's surface plane is available, such as planes in building information modeling (BIM) systems. This article presents a localization technique based on a-priori plane point cloud extraction. The position and pose of the mobile robot are estimated through real-time multi-plane constraints. An extended image coordinate system is proposed to represent any planes in space and establish correspondences between visible planes and those in the world coordinate system. Potentially visible points representing the constrained plane in the real-time point cloud are filtered using the filter region of interest (ROI), derived from the theoretical visible plane region within the extended image coordinate system. The number of points representing the plane influences the calculation weight in the multi-plane localization approach. Experimental validation of the proposed localization method demonstrates its allowance for redundancy in initial position and pose error.

Precision-Driven Multi-Target Path Planning and Fine Position Error Estimation on a Dual-Movement-Mode Mobile Robot Using a Three-Parameter Error Model.

The multi-target path planning problem is a universal problem to mobile robots and mobile manipulators. The two movement modes of forward movement and rotation are universally implemented in integrated, commercially accessible mobile platforms used in logistics robots, construction robots, etc. Localization error in multi-target path tracking is one of the crucial measures in mobile robot applications. In this article, a precision-driven multi-target path planning is first proposed. According to the path's odometry error evaluation function, the precision-optimized path can be discovered. Then, a three-parameter odometry error model is proposed based on the dual movement mode. The error model describes localization errors in terms of the theoretical motion command values issued to the mobile robot, the forward moving distances, and the rotation angles. It appears that the three error parameters follow the normal distribution. The error model is finally validated using a mobile robot prototype. The error parameters can be identified by analyzing the actual moving trajectory of arbitrary movements. The experimental localization error is compared to the simulated localization error in order to validate the proposed error model and the precision-driven path planning method. The OptiTrack motion capture device was used to capture the prototype mobile robot's pose and position data.

Potential active compounds and molecular mechanism of Xuefu Zhuyu decoction for atherosclerosis, based on network pharmacology and molecular docking.

To explore the potential active compounds and molecular mechanism of Xuefu Zhuyu decoction (XFZYD) in the treatment of atherosclerosis (AS) based on network pharmacology and molecular docking. The effective components and action targets of XFZYD were screened by using TCMSP database. And then, the action targets of AS were collected by GeneCards database. The intersection targets between the effective components' targets of XFZYD and AS-related action targets were used to construct PPI networks. GO and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed on these intersection targets. Finally, molecular docking software was used to excavate the active compounds of the core targets VEGFA and AKT1. We detected 225 active components of XFZYD, and found that quercetin, kaempferol, luteolin, naringenin, ß-sitosterol, isorhamnetin, stigmasterol, baicalein, nobiletin, and ß-carotene are the potential active compounds of XFZYD; STAT3, IL6, JUN, VEGFA, MAPK14, and AKT1 are the core target proteins of the active compounds, among which VEGFA and AKT1 are the key target proteins. PPI network results showed that ß-carotene, quercetin, kaempferol, luteolin, and naringenin had higher degree values and more corresponding targets than other 5 active compounds and had the stable binding ability to regulatory proteins VEGFA and AKT1. The core components ß-carotene, quercetin, kaempferol, and luteolin exerted their therapeutic effects on AS by acting on the key target proteins VEGFA and AKT1 to regulate fluid shear stress and the AGE-RAGE signaling pathway and IL-17 signaling pathway of diabetic complications of AS. The molecular docking results showed that VEGFA and AKT1 had great docking ability with the targeted active compounds, and ß-carotene is the best. The active components of XFZYD, including ß -carotene, quercetin, kamanol, and luteolin, can act on VEGFA and AKT1. These active ingredients play a role in alleviating and treating AS by regulating fluid shear stress and participating in signaling pathways such AS AGE-RAGE of atherosclerosis and diabetes mellitus complicated with AS. ß-carotene is a potential inhibitor of VEGFA and AKT1 and treats AS through antioxidant action.

Bioinspired morphing wings: mechanical design and wind tunnel experiments.

Bioinspired morphing wings are part of a novel research direction offering greatly increased adaptability for use in unmanned aerial vehicles. Recent models published in the literature often rely on simplifications of the bird wing apparatus and fail to preserve many of the macroscopic morphological features. Therefore, a more holistic design approach could uncover further benefits of truly bioinspired bird wing models. With this issue in mind, a prototype inspired by crow wings (Corvusgenus) is developed, which is capable of planform wing morphing. The prototype imitates the feather structure of real birds and replicates the folding motion with a carbon fiber reinforced polymer skeleton with one controllable degree of freedom. The mechanism supplies a smooth airfoil lifting surface through a continuous morphing motion between a fully extended and a folded state. When extended, it has an elliptic planform and emarginated slots between primary remiges. In the folded state, the wingspan is reduced by 50% with a 40% reduction in surface area and the aspect ratio decreases from 2.9 to 1.2. Experimental data from a subsonic wind tunnel investigation is presented for flow velocities ranging from 5 to 20 m s-1, corresponding to Reynolds numbers between 0.7 × 105-2.8 × 105. The wing is analyzed in the three static states (folded, intermediate, and extended) through aerodynamic coefficients and flow visualizations along the surface. The bioinspired design enables the wing to capture several phenomena found on real bird wings. Through its morphing capabilities and intrinsic softness, the wing can sustain large angles of attack with greatly delayed stall and maintain optimal performance at different velocities.

Reconstruction of Flight Parameters of a Bat for Flapping Robots.

The flight of bats is comparatively less documented and understood than birds and insects and may provide novel inspiration for the design of flapping flight robots. This study captured the natural flight of short-nosed fruit bats (Cynopterus sphinx) by an optical motion capture system, "OptiTrack", with pasted markers on the wings and body to reconstruct the flight parameters. Due to the self-occlusion at some moments, points on the membrane wings cannot be captured by any cameras. To draw a smooth trajectory, it is desired to reconstruct all missing data. Therefore, an algorithm is proposed by using numerical techniques, accompanied by modern mathematical and computational tools, to envisage the missing data from the captured flight. The least-square fitted polynomial engendered the parameter equations for x-, y-, and z-coordinates of marked points which were used to reconstruct the trajectory of the flight. The parameter equations of position coordinates were also used to compute the morphological and aerodynamic characteristics of the flight. The most outstanding contribution of the work is that not only the trajectory, velocity, and velocity field but also the morphing areas of the membrane wings were recreated using the reconstructed data. These data and reconstructed curves of trajectory and velocity field will be used for the further aerodynamic analysis and mechanism design of the flapping robot. This method can also be generalized to reconstruct the performance parameters of any other animals for bionic design.

Hydroxysafflower Yellow A Inhibits Vascular Adventitial Fibroblast Migration via NLRP3 Inflammasome Inhibition through Autophagy Activation.

Inflammation is closely associated with progression of vascular remodeling. The NLRP3 inflammasome is the key molecule that promotes vascular remodeling via activation of vascular adventitia fibroblast (VAF) proliferation and differentiation. VAFs have a vital effect on vascular remodeling that could be improved using hydroxysafflower yellow A (HSYA). However, whether HSYA ameliorates vascular remodeling through inhibition of NLRP3 inflammasome activation has not been explored in detail. Here, we cultured primary VAFs and analyzed the migration of VAFs induced by angiotensin II (ANG II) to determine the potential effects and mechanism of HSYA on VAF migration. The results thereof showed that HSYA remarkably inhibited ANG II-induced VAF migration, NLRP3 inflammasome activation, and the TLR4/NF-κB signaling pathway in a dose-dependent manner. In addition, it is worth noting that LPS promoted ANG II-induced VAF migration and NLRP3 inflammasome assembly, which could be significantly reversed using HSYA. Moreover, HSYA could be used to inhibit NLRP3 inflammasome activation by promoting autophagy. In conclusion, HSYA could inhibit ANG II-induced VAF migration through autophagy activation and inhibition of NLRP3 inflammasome activation through the TLR4/NF-κB signaling pathway.

Direct Measurements of the Wing Kinematics of a Bat in Straight Flight.

Bat is the only mammal in the nature that can fly. Compared with birds and insects, bats are quite special in that their wings are formed by an elastic membrane, which renders that the airfoil deforms greatly during downstroke and upstroke. Due to the compliant skin of a bat, the movements of its wings are three-dimensionally complex during diverse flight behaviors. To understand the maneuverability and flight performance, three-dimensional reconstruction of the flight kinematics is essential. This study focuses on the reconstruction of the wing kinematics of the bat and identifies the primary relationship of parameters of aerodynamics in straight flight. With markers pasted on the wings and body of a bat, the motions of these points are recorded by a computerized optical motion capture system. The kinematic analysis shows that the motion of wings is very intricate. The digits of the wing display the sign of coupled motion. A novel approach was developed to measure the angle of attack and flapping angle of the wing. The angle of attack of leading edge differs with the overall angle of attack of the wing. The kinematics of the bat's wing is helpful to interpret the secret of the bat's flight.

Data of feather recovering performance of birds and micro structure of pigeons' feathers.

Data is presented to explain why birds can recover their ruffled feather vanes by shaking wings and preening feathers with the beak [1]. Presented data includes the SEM microscopic images of rachis, barbs and barbules of pigeon's feather and the images recording the experiments of observing and mimicking the recovering performance of pigeons. Besides, based on the measurement and observation of the micro structure of feathers, the mechanical models of barbules were developed to better understand the wings performance. These high-quality images and models could be used for future research on feathers. Data helps to better understand the micro structure of feathers and the reason birds can fly. Data also support bioinspired mechanical structure development, especially for flapping robot development.

Identification of avian flapping motion from non-volant winged dinosaurs based on modal effective mass analysis.

The origin of avian flight is one of the most controversial debates in Paleontology. This paper investigates the wing performance of Caudipteryx, the most basal non-volant dinosaur with pennaceous feathered forelimbs by using modal effective mass theory. From a mechanical standpoint, the forced vibrations excited by hindlimb locomotion stimulate the movement of wings, creating a flapping-like motion in response. This shows that the origin of the avian flight stroke should lie in a completely natural process of active locomotion on the ground. In this regard, flapping in the history of evolution of avian flight should have already occurred when the dinosaurs were equipped with pennaceous remiges and rectrices. The forced vibrations provided the initial training for flapping the feathered wings of theropods similar to Caudipteryx.

Winged forelimbs of the small theropod dinosaur Caudipteryx could have generated small aerodynamic forces during rapid terrestrial locomotion.

Pennaceous feathers capable of forming aerodynamic surfaces are characteristic of Pennaraptora, the group comprising birds and their closest relatives among non-avian dinosaurs. However, members of the basal pennaraptoran lineage Oviraptorosauria were clearly flightless, and the function of pennaceous feathers on the forelimb in oviraptorosaurs is still uncertain. In the basal oviraptorosaur Caudipteryx both the skeleton and the plumage, which includes pennaceous feathers forming wing-like arrangements on the forelimbs, are well known. We used mathematical analyses, computer simulations and experiments on a robot Caudipteryx with realistic wing proportions to test whether the wings of Caudipteryx could have generated aerodynamic forces useful in rapid terrestrial locomotion. These various approaches show that, if both wings were held in a fixed and laterally extended position, they would have produced only small amounts of lift and drag. A partial simulation of flapping while running showed similarly limited aerodynamic force production. These results are consistent with the possibility that pennaceous feathers first evolved for a non-locomotor function such as display, but the effects of flapping and the possible contribution of the wings during manoeuvres such as braking and turning remain to be more fully investigated.

Roscovitine attenuates intimal hyperplasia via inhibiting NF-κB and STAT3 activation induced by TNF-α in vascular smooth muscle cells.

Roscovitine is a selective CDK inhibitor originally designed as anti-cancer agent, which has also been shown to inhibit proliferation in vascular smooth muscle cells (VSMCs). However, its effect on vascular remodeling and its mechanism of action remain unknown. In our study, we created a new intimal hyperplasia model in male Sprague-Dawley rats by trypsin digestion method, which cause to vascular injury as well as the model of rat carotid balloon angioplasty. Roscovitine administration led to a significant reduction in neointimal formation and VSMCs proliferation after injury in rats. Western blot analysis revealed that, in response to vascular injury, TNF-α stimulation induced p65 and STAT3 phosphorylation and promoted translocation of these molecules into the nucleus. p65 can physically associate with STAT3 and bind to TNF-α-regulated target promoters, such as MCP-1 and ICAM-1, to initiate gene transcription. Roscovitine can interrupt activation of NF-κB and reduce expression of TNF-α-induced proinflammatory gene, thus inhibiting intimal hyperplasia. These findings provide a novel mechanism to explain the roscovitine-mediated inhibition of intimal hyperplasia induced by proinflammatory pathways.

Roscovitine Protects From Arterial Injury by Regulating the Expressions of c-Jun and p27 and Inhibiting Vascular Smooth Muscle Cell Proliferation.

PURPOSE: Roscovitine (Rosc) is a selective inhibitor of cyclin-dependent kinases (CDKs) and a promising therapy for various cancers. However, limited information is available on the biological significance of Rosc in vascular smooth muscle cells (VSMCs), the cell type critical for the development of proliferative vascular diseases. In this study, we address the effects of Rosc in regulating VSMC proliferation, both in vitro and in vivo, exploring the underlying molecular mechanisms. METHODS: The proliferations and cell-cycle distributions of in vitro cultured VSMCs, as well as several other cancer cell lines, were examined by cell-counting assay and flow cytometry, respectively. Molecular changes in various CDKs, cyclins, and other regulatory molecules were examined by reverse transcription polymerase chain reaction, Western blot, or immunocytochemistry. The in vivo effects of Rosc were examined on a carotid arterial balloon-injury model. RESULTS: Rosc significantly inhibited VSMC proliferation in response to serum or angiotensin II and arrested these cells at the G0/G1 phase. These changes were associated with a specific and robust decrease in CDK4, cyclin E, c-Jun, and a dramatic increase in p27kip1 in VSMCs, which was also translated in vivo and correlated with the protection of Rosc on injury-induced neointimal hyperplasia. CONCLUSIONS: Acting on distinct molecular targets in VSMCs versus cancer cells, Rosc inhibits VSMC proliferation and protects from proliferative vascular diseases.

Endometrial breakdown with sustained progesterone release involves NF-κB-mediated functional progesterone withdrawal in a mouse implant model.

Irregular uterine bleeding is a major side effect of long-acting progestogen-only contraceptives in women, and is the primary reason women discontinue their use. In this study, a mouse model of endometrial breakdown was established using a subcutaneous progesterone implant to understand how irregular bleeding begins. Although progestogens sustained decidualization, endometrial breakdown was still observed in this model. We, therefore, hypothesized that endometrial breakdown might involve functional progesterone withdrawal. Using co-immunoprecipitation assays, we observed the constitutive activation of nuclear factor kappa-b (NF-κB) p65 and its interaction with the progesterone receptor (PGR); moreover, transcriptional activity of the PGR was also repressed by NF-κB activity in primary mouse and human decidual stromal cells that mimic progesterone maintenance. Yet the ratio of PGR-B to PGR-A was not increased in the mouse model. In vivo comparison of endometrial breakdown induced by progesterone withdrawal to that seen during sustained progesterone exposure, in the presence of NF-κB inhibitors, revealed that NF-κB-mediated functional progesterone withdrawal is involved in endometrial breakdown in this implant model. These data prompt further studies to determine the homology of this functional progesterone withdrawal mechanism in human endometrium. Mol. Reprod. Dev. 83: 780-791, 2016 © 2016 Wiley Periodicals, Inc.

Acetylbritannilactone Modulates Vascular Endothelial Growth Factor Signaling and Regulates Angiogenesis in Endothelial Cells.

The present study was conducted to determine the effects of 1-O-acetylbritannilactone (ABL), a compound extracted from Inula britannica L., on vascular endothelial growth factor (VEGF) signaling and angiogenesis in endothelial cells (ECs). We showed that ABL promotes VEGF-induced cell proliferation, growth, migration, and tube formation in cultured human ECs. Furthermore, the modulatory effect of ABL on VEGF-induced Akt, MAPK p42/44, and p38 phosphorylation, as well as on upstream VEGFR-2 phosphorylation, were associated with VEGF-dependent Matrigel angiogenesis in vivo. In addition, animals treated with ABL (26 mg/kg/day) recovered blood flow significantly earlier than control animals, suggesting that ABL affects ischemia-mediated angiogenesis and arteriogenesis in vivo. Finally, we demonstrated that ABL strongly reduced the levels of VEGFR-2 on the cell surface, enhanced VEGFR-2 endocytosis, which consistent with inhibited VE-cadherin, a negative regulator of VEGF signaling associated with VEGFR-2 complex formation, but did not alter VE-cadherin or VEGFR-2 expression in ECs. Our results suggest that ABL may serve as a novel therapeutic intervention for various cardiovascular diseases, including chronic ischemia, by regulating VEGF signaling and modulating angiogenesis.

Hydroxysafflor yellow A inhibits rat vascular smooth muscle cells proliferation possibly via blocking signal transduction of MEK-ERK1/2 / 中华心血管病杂志

<p><b>OBJECTIVE</b>To elucidate the effect of hydroxysafflor yellow A ( HYSA) on the proliferation of vascular smooth muscle cells (VSMCs) and the related mechanism.</p><p><b>METHODS</b>VSMCs derived from SD rats were treated with DMEC culture medium (Control), 10 ng/ml PDGF (PDGF group), pretreatment with HYSA at different doses (1, 5, 10, 20, 40, 60 µmol/L) for 24 h then cotreatment with PDGF. After 24 h, MTT assay, Western blot and immunohistochemical staining were performed to evaluate the inhibitory effects of HYSA on VSMCs proliferation.</p><p><b>RESULTS</b>HYSA inhibited PDGF induced VSMCs proliferation in a dose-dependent manner, dowregulated proliferating cell nuclear antigen (PCNA) expression and blocked PDGF activated PDGFR-MEK-ERK1/2 signaling pathway.</p><p><b>CONCLUSIONS</b>HYSA inhibits VSMCs proliferation possibly via downregulating the expression of PCNA and blocking MEK-ERK1/2 signal transduction in VSMCs.</p>

Reduced endoplasmic reticulum stress might alter the course of heart failure via caspase-12 and JNK pathways.

BACKGROUND: Endoplasmic reticulum (ER) stress plays an important role in mediating ischemic heart cell death. The aim of this study was to investigate whether manipulation of a key factor of the ER stress pathway, eukaryotic translation initiation factor 2 subunit α (eIF2α), can change the natural history of heart failure (HF). METHODS: HF was induced using coronary artery ligation in adult rats and a selective eIF2α dephosphorylation inhibitor, salubrinal (Sal), was used. Thirty minutes after ligation, rats were randomly assigned to 3 groups: myocardial infarction (MI) plus placebo injections (dimethyl sulfoxide; n = 12), MI plus Sal injection (Sal; n = 12), and MI (HF; n = 12). Hemodynamic parameters were examined. Hearts were harvested for apoptosis assessment after 8 weeks of Sal treatment by terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labelling and flow cytometric analysis. Hearts were harvested to determine ER chaperones by Western analysis, real-time polymerase chain reaction and immunohistochemical analysis. RESULTS: Cardiac function was significantly improved in Sal-treated rats. Apoptosis was reduced by Sal treatment. Glucose-regulated protein-78 and -94 were increased in HF but normalized by Sal treatment. HF caused a significant increase in eIF2α phosphorylation, which was further increased by Sal treatment, and caspase-12 and phospho-c-JUN NH2-terminal kinase were markedly increased in rats with HF alone but significantly reduced by Sal treatment. CONCLUSIONS: Our results suggest that reduction of ER stress and myocardial apoptosis through inhibition of eIF2α dephosphorylation might alter the natural history of HF, which might provide a new approach for its treatment.

On-line concentration and pressurized capillary electrochromatographic analysis of phytohormones in corn.

A pressurized CEC (pCEC) method was developed for the separation of phytohormones, in which UV absorbance was used as the detector and a monolithic silica-ODS column as the separation column. The parameters (including the concentration of organic solvent in the mobile phase, pH of the electrolyte buffer, applied voltage) affecting the separation resolution were evaluated. Two on-line concentration techniques, namely, solvent gradient zone sharpening effect and field-enhanced sample stacking, were utilized to improve detection sensitivity. The combination of the two techniques proved to be beneficial to enhance the detection sensitivity by enabling the injection of large volumes of samples. Compared to the conventional injection mode, the enhancement in the detection sensitivities of phytohormones using the on-line concentration technique is in the range from 9- to 23-fold. The developed pCEC method was applied to evaluate phytohormones in corns.

[Determination of acetylbritannilactone in inulicin and rat plasma by micellar electrokinetic capillary chromatography with on-line sweeping concentration technique].

A method was established for the determination of acetylbritannilactone (ABL) in inulicins and rat plasma by micellar electrokinetic capillary chromatography (MECC), in which on-line sweeping technique was applied to elevate the sensitivity of the detection. The column used was an uncoated fused silica capillary with a size of 57 cm (effective length of 50 cm) x 75 microm i.d. Electrode buffer was a 50 mmol/L borate buffer containing 50 mmol/L sodium lauryl sulfate (SDS) (pH 9.5). Sample buffer was a 10 mmol/L borate buffer (pH 9.5). Other conditions were as follows: separation voltage, 23 kV; detection wavelength, 195 nm; sample injection, 3.45 kPa (0.5 psi) x 5 s; column temperature, 25 degrees C. The on-line sweeping-MECC had excellent linearity with correlation coefficient of 0. 997 5, and reproducibility with the relative standard deviation of ABL migration time less than 5%. The recovery was more than 92%, and the sensitivity was 0.005 g/L. ABL in inulicin and their dynamic change in vivo were determined by sweeping-MECC. The results indicate that on-line sweeping-MECC is a simple and rapid method for the determination of trace biological sample. The method needs only micro-amount of samples, and is characterized by higher degree of automation and sensitivity.