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Microwave-promoted cyclocondensation of isoflavones with 3-amino[1,2,4]triazole gave 6-phenyl-7-(2-hydroxyphenyl)-1,2,4triazolo[4,3- a ]pyrimidines as intermediates. Subsequent photocyclization of these intermediates delivered dibenzo[ f , h ][1,2,4]triazolo[3,4- b ]quinazolines as final products. Water was the only by-product in this two-step procedure. The products showed distinct fluorescence properties both in solution and in the solid state .

In the Mars exploration mission, the lander's buffer landing task is a key step. Because of the characteristics of discrete element theory, it is not only widely used in geotechnical analysis, pharmaceutical and other fields, but also in the field of aerospace, especially in the simulation of the surface of the planet such as Stardust and other discrete surface. In this paper, a particle — spring model based on discrete element theory is proposed, which is used to model the Martian airbag by using the EDEM of discrete element simulation software. Then, the simulation and analysis of the special environment such as hard ground and desert surface of Mars are carried out to verify the necessity of the model in the simulation of the landing characteristics of the airbag.

The crawling robot plays an important role in the space mission, such as detection, assemblage and repairing, which can even be an indispensable technology. For the task of unmanned space truss assembly in the future, this paper presents a kind of underactuated pole-climbing robot based on the mechanism of adhesion. The influences of adhesion of the legs' part of the robot was researched and analysed through the coupling simulation of EDEM and ADAMS, after which we got the adhering force between the legs' part and its climbing objects. The simulation results can provide guidance and theoretical basis for the detailed design of this kind of robot.

At present, the robot arm technology occupies the dominant position in the space payload control field. However, with the limitations of robot arm technology, the load control technology with higher flexibility and mobility came into being. The space miniature climbing robot performs on-orbit control tasks such as fault repair and waste removal by crawling through the robotic arm and adhering to the target spacecraft. In this paper, the adhesion characteristic of space climbing robot is studied, an adhesion microarray structure is proposed, and the influence of the contact area, slenderness ratio, length, diameter and density of the microarray on the adhesion characteristics in the zero - gravity environment is analyzed respectively by using the discrete element software EDEM. Results show that: 1) Increasing the density of array with no fibers tangling each other, can obtain the larger adhesion. 2) In order to obtain a larger tangential adhesion, the fiber diameter should be increased and the length be reduced, while in the actual environment, the length/diameter ratio should be appropriately increased because limitation of adaptability to the surface.

Dynamic penetration test by a penetrator is an important detection method for lunar exploration. The analysis of the dynamic penetration properties of the penetrator significantly helps to design the penetrator structure. In this article, the dynamic penetration mechanical model was established according to soil mechanics. Then, the discrete-element simulation model, which was established using the application program interfaces of the EDEM software, was used to simulate the penetration process. The penetration experiment demonstrated the accuracy of the dynamic penetration model and the discrete-element simulation model. This study of dynamic penetration model of a penetrator may provide technical support to the deep space exploration.

Preeclampsia (PE) is initiated by abnormal placentation in the early stages of pregnancy, followed by systemic activation of endothelial cells of the maternal small arterioles in the late second or third trimester (TM) of pregnancy. During normal pregnancy, placental cytotrophoblasts (CTBs) invade the maternal uterine wall and spiral arteries, whereas this process is interrupted in PE. However, it is not known how the malformed placenta triggers maternal endothelial crisis and the associated manifestations. Here, we have focused on the association of CD81 with PE. CD81, a member of the tetraspanin superfamily, plays significant roles in cell growth, adhesion, and motility. The function of CD81 in human placentation and its association with pregnancy complications are currently unknown. In the present study, we have demonstrated that CD81 was preferentially expressed in normal first TM placentas and progressively down-regulated with gestation advance. In patients with early-onset severe PE (sPE), CD81 expression was significantly up-regulated in syncytiotrophoblasts (STBs), CTBs and the cells in the villous core. In addition, high levels of CD81 were observed in the maternal sera of patients with sPE. Overexpressing CD81 in CTBs significantly decreased CTB invasion, and culturing primary human umbilical vein endothelial cells (HUVECs) in the presence of a high dose of exogenous CD81 resulted in interrupted angiogenesis and endothelial cell activation in vitro. Importantly, the phenotype of human PE was mimicked in the CD81-induced rat model.

P-glycoprotein (P-gp), an important efflux transporter, is encoded by the MDR1 class of genes and is a major element of the multidrug resistance (MDR) phenomenon in breast cancers. The most common approved cause of MDR in cancer tissues is the over-expression of P-gp. At present, a novel potent anti-tumor compound RY10-4 has been synthesized by our team, which has a similar structure close to protoapigenone. We chose MCF-7/ADR cells, an adriamycin (ADR) – selected human breast tumor cell line with the MDR phenotype, to study the anticancer features of this novel compound in our experiments. In cytotoxicity and apoptosis tests, it was shown that RY10-4 significantly inhibited cell growth, induced apoptosis, potentiated ADR cytotoxicity and restored chemotherapy sensitivity in the MDR cancer cells. Furthermore, our results suggested that RY10-4 reversed MDR partially by down-regulation of P-gp and MDR1 expressions in the MCF-7/ADR cell line. Besides, it is seen that RY10-4 could reduce the intracellular ATP level. Our studies give the theoretical basis for the possible clinical applications of RY10-4 alone or in combination with other chemotherapeutic drugs in the treatment of MDR tumors.

In the article, we investigated the anti-metastasis mechanism of RY10-4, an anti-tumor compound derived from protoapigenone, in breast tumor cells MB-MDA-231. The analog of protoapigenone with an unaromatic B-ring was verified to suppress the proliferation of several tumor cells by previous research that also showed that several tumor progression such as inducing apoptosis and anti-angiogenesis could be acted on by RY10-4. In the article, we investigated the mechanism about how RY10-4 suppressed the invasion of MDA-MB-231. Firstly, the transwells assays with and without matrigel were adapted to evaluate the anti-metastasis and anti-invasion activity. Much research had demonstrated that the ECM and E-cadherin/β-catenin complex play an important role in cell adhesion and the formation of the cell skeleton, and as we knew the abnormal and absent expression of ECM and E-cadherin/β-catenin complex are found in many malignant cells. The result demonstrated that the amount and distribution of E-cadherin/β-catenin complex were backed on track by RY10-4, and the expression of MMP-2/9 in MDA-MB-231, which functions as a major negative factor of ECM, was down-regulated after co-cultured with RY10-4. Furthermore the pathway related to MMP-2/9 and E-cadherin was assessed by the western blot. As the results showed, the MAPK pathway and the spread of β-catenin were affected by RY10-4 to exert the anti-metastasis on MDA-MB-231. Collectively, the research revealed a novel anti-tumor ability of RY10-4 by inhibiting migration and invasion in MDA-MB-231.

Previous reports suggested that protoapigenone showed remarkable antitumor activities against a broad spectrum of human cancer cell lines, but had no effect on human lung adenocarcinoma A549 cell. The lack of effective remedies had necessitated the application of new therapeutic scheme. A novel compound RY10-4 which has the similar structure close to protoapigenone showed better antitumor activity. Treatment with RY10-4 inhibited the expression of pro-caspase-3, pro-caspase-9, Bcl-2 as well as phosphorylation of signal transducer and activator of transcription-3 (p-STAT3). It also reduced the expressions of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and increases the expressions of reversion-inducing cysteine-rich protein with kazal motifs (RECK), as well as tissue inhibitor of metalloproteinase (TIMP) via inhibiting STAT3 by activating the mitogen-activated protein (MAP) kinases (the c-Jun N-terminal kinase (JNK), the p38 and extracellular signal-regulated kinase (ERK)) in A549 cells treated with RY10-4. Moreover, the cytotoxic effect of RY10-4 was induction of apoptosis in A549 cells by enhancing production of reactive oxygen species (ROS). Taken together, the observations suggested that RY10-4 had affected Bcl-2 family members, caspases, MMPs, TIMPs expressions and ROS production via inhibiting STAT3 activities through ERK and p38 pathways in A549 cells.

For the on-orbit servicing missions of spacecraft, space robot is considered as one of the most promising approaches. Many on-orbit servicing missions are successfully accomplished and most of these missions are designed to service cooperative targets only. Some of the target is non-cooperative spacecraft with unknown motion and kinematics properties. On-orbit servicing is still a challenging research area. The challenge is to ensure the servicing spacecraft safely and stabilize it for subsequent servicing. In order to expand space robot workspace and its task function, this paper presents a new type of space climbing robot which can be carried on mechanical arm. It can climb onto the target spacecraft for repairing, rescuing and removing orbital debris when the connection is established between the space manipulator and the target spacecraft. This robot mobile system is composed of piezoelectric actuation leg, micro adhesive feet, ejector and manipulator. The robot’s crotch joint and ankle joint both have two degrees of freedom with Roll-Pitch organization. In the environment of zero-gravity the obstacles on the target can be crossed by space climbing robot through wriggle movement and turnover movement. The gripping force of the robot is supplied by the adhesive capacity of the robot feet while robot climb along the surface of target spacecraft with weightlessness. The research of its adhesion mechanism is the basis of robot feet design and motion control. The design of robot feet micro array structure imitates the adhesion mechanism of gecko seta. A contact model between the robot feet and spacecraft surface is proposed. A single seta’s DEM (Discrete Element Method) model is set up by stacking micro particles, on the software platform of EDEM. EDEM is a software for discrete element analysis. The attachment and the detachment process of a single seta in different slope angle and its adhesion properties are simulated by using JKR model which is a classical contact mechanics model. The simulation demonstrate that the single seta’s gripping force with 90 degree slope angle is about 20% of the gripping force with 30 degree slope angle. The fiber structure was destroyed by large pressure making failure to its adhesion properties when the slope angle is zero. So the different ways of movement can achieve different adhesion properties of single seta. When the movement of micro array structure is determined, in order to improve the robust adhesion properties, well stability and excellent adaptability of the micro array structure, the structure parameters of seta is optimized. The structure parameters include the cylinder radius, length-diameter ratio and arrangement density of the micro array structure. A group of micro array structure optimized parameters is given according to the DEM comparing simulations with different structure parameters. This work propose a novel adhesion concept for climbing robot in space environment, and the stable attaching and easy detaching mechanism of the robot is also given.

The acquirement of lunar soil samples is the foundation to analyze and know about the composition of lunar soil and the lunar geologic structure. Because of the restrictions of the sampling method, the size of driller, the drilling pressure and the driller’s output power, the traditional digging method and vertical drilling method can only acquire the samples from lunar surface to 3 meters deep. In order to acquire the deeper samples based on the existing technique methods, a new exploration concept in which a driller fixed on the rover takes a horizontal drilling and sampling at the cross section of a crater after cleaning the surface chaotic soil was proposed in this paper. When drilling horizontally, the maximum drilling pressure is limited by the low adhesive ability between wheels and soil. For the purpose of making sure enough drilling pressure, study was carried out in this paper to improve the wheel’s adhesive ability by modifying the wheel’s surface. A wheel with a new kind of micro convex structures was proved to be more adhesive and stable during horizontal drilling by comparing with the existing wheel structures, such as wheel with thorns or discontinuous rims. The structural parameters of the convex structures may have significant influences on the adhesive ability. In order to study the effects of the convex structure’s parameters on wheel’s adhesive ability, the motion process of wheels on sandy road was simulated by using a DEM software EDEM. According to the simulation results, when the structural parameters of the convex structures are: flat-end shape, length/diameter = 5 and distribution density = 81/mm2, the wheel’s adhesive ability is much better than the wheel with other parameters based on a criterion which is the ratio of the tangential force to the normal force in the tangential motion process. Besides, the friction coefficient of wheels with convex structures is about 5 times as much as the friction coefficient of normal wheels, which proves that it is a useful method to improve wheel’s adhesive ability by modifying wheel’s surface with the convex structures.

To investigate the effect of dihydrotestosterone (DHT) combined with Dezawa’s method on the differentiation of bone marrow stromal cells (BMSCs) into schwann-like cells. Compared to the Dezawa’s method, schwann-like cells obtained from our modified method were longer and thinner and exhibited a typical bipolar or tripolar shape. These cells had a higher mRNA expression of S100 and myelin protein zero (P0), about 1.7- and 2.5-fold respectively, while the glial fibrillary acidic protein (GFAP) mRNA level was decreased about 92 %. No significant difference in peripheral myelin protein 22 (PMP22) mRNA expression was found. Immunofluorescence and Western blot showed the similar results. DHT in combination with Dezawa’s method to induce a BMSCs to differentiate into schwann-like cells with higher expression of P0, which might be more effective in clinical application than previous method for nerve regeneration.

Landing-impact between lander and lunar regolith is the decisive factor to soft landing and relates directly to the safety of detection equipment. In this paper, the landing-impact process and the interaction between lander and regolith is researched using the discrete element simulation. Firstly, the landing-impact model is established based on discrete element theory and the mechanical properties of lunar regolith. Many simulations in different working conditions are conducted to study the vertical impact. Secondly, to study the process of landing-impact, dynamic response, stress distribution and motion in a certain condition are studied and the phenomenon of landing impact is explained. Finally, the influence of velocity and mass on the landing-impact is summarized through contrastive analysis. The research in this paper provides reference for the design of lander buffering mechanism and the establishment of the theoretical model.

At present, control methods of the six-wheeled rocker lunar rover primarily consist of setting the same driving parameters for each wheel. This type of control method ignores the multiple active driving characteristics of the lunar rover and causes parasitic power loss. The main cause of the parasitic power loss is the uncoordinated motion of the driving elements. Therefore, in this article, a coordinated motion programming model of the six-wheeled rocker lunar rover based on the velocity projection theorem, the quasi-static mechanical model, and the rated power of the motor is established to eliminate parasitic loss, reduce driving energy, and improve energy efficiency. The analytical solution of the programming model based on the Kuhn–Tucker condition is also calculated. The coordinated motion control model saves energy, and it is suitable for other wheeled-type planet rovers. This model provides technical support for reducing the energy consumption of planet rovers.

In order to reduce the destruction of lunar dust electrostatic adhesion on detector and related equipment, technology of particle removal and charging model are researched. The technology of photoelectric dedusting is proposed. According to the particle orbit theory, current of photoelectron and electron are respectively obtained. Based on Maxwell energy distribution, the density distribution function of each particle is obtained. Then, charging model of lunar dust is setup. The model is solved by Runge-Kutta Method and charging regulation of lunar dust is obtained. Based on charging model, electrostatic adhesion force of nanoscale particles is got by discrete element software. At last, effect of solar radiation intensity on electrostatic adhesion is researched by discrete element software.

Microwave-promoted cyclocondensation of isoflavones with 3-amino[1,2,4]triazole gave 6-phenyl-7-(2-hydroxyphenyl)-1,2,4triazolo[4,3- a ]pyrimidines as intermediates. Subsequent photocyclization of these intermediates delivered dibenzo[ f , h ][1,2,4]triazolo[3,4- b ]quinazolines as final products. Water was the only by-product in this two-step procedure. The products showed distinct fluorescence properties both in solution and in the solid state .

MiR-155 is known to participate in various cellular processes by targeting gene expression. We previously revealed a link between miR-155 and perturbation of trophoblast invasion and differentiation. This study aimed to investigate the target molecule(s) of miR-155 on the influence on the proliferation and migration of trophoblast cells. Bioinformatics analysis showed that, at the 3' untranslated region (UTR) of cyclin D1, six bases are complementary to the seed region of miR-155. Luciferase assays and cyclin D1 3'UTR transfection assays validated that cyclin D1 3'UTR was the target of miR-155 in HTR-8/SVneo cells. Overexpression of miR-155 in HTR-8/SVneo cells reduced the level of cyclin D1 protein, decreased cell proliferation and invasion, and increased cell number at the G1 stage. Furthermore, the increased expression of miR-155 also regulated the protein levels of kinase inhibitory protein p27 and phosphorylated cytoskeletal protein filamin A. In conclusion, we found that cyclin D1 may be a target of miR-155 in HTR-8/SVneo cells, and demonstrated a negative regulatory role of miR-155 involved in cyclin D1/p27 pathway in proliferation and migration of the cells.

To assess the anti-angiogenesis potential and mechanism of RY10-4, a derivative of protoapigenone, which was verified the broad-spectrum anti-tumor activities by previous study. RY10-4 and RY10-3 were synthesized according to the procedure described. Breast cancer cells MCF-7 and MDA-MB-231 that got the best performance in the previous anti-tumor activity screening were selected for further anti-cancer mechanism research. Firstly, cells proliferation assay of RY10-4 and RY10-3 was used to demonstrate the fact that the 4-hydroxy-2,5-cyclohexadien-1-one system would be the efficient pharmacophore of RY10-4. Then, a series of assays such as human umbilical vein endothelial cells (HUVECs) proliferation assay, HUVECs migration, tube network formation and morphological observations of zebrafish were applied to confirm its anti-angiogenesis activity. Upon RY10-4 treatment, the HIF-1α and VEGF were analyzed by western blot in normoxic and hypoxic conditions, meanwhile the PI3K-AKT-mTOR pathway-related protein such as AKT, p-AKT, mTOR and p-mTOR was also analyzed. In the MCF-7, MDA-MB-231 and HUVECs proliferation assay, RY10-4 that has 4-hydroxy-2,5-cyclohexadien-1-one system showed distinct advantage compared with RY10-3. Tests had verified the anti-angiogenesis capability of RY10-4. Down-regulation of the HIF-1α and inhibition phosphorylation levels of AKT and mTOR were found to be the pathway that RY10-4 exerts its functions on anti-angiogenesis. The structure of 4-hydroxy-2,5-cyclohexadien-1-one should be the effective pharmacophore of RY10-4. RY10-4 got fine performance in anti-tumor and anti-angiogenesis assay, and thus, the quinol compound will be the new hot-spot for further anti-tumor agency development.

The mechanism for plants around the soil threshold of drought (close to the soil wilting water content) is a problem that needs to be further explored. In this paper, Artemisia ordosica, which grows in the Tengri Desert, was selected to analyze the changes in the plant water potentials in the soil-plant-atmosphere continuum (SPAC), the water contents in the roots, shoots and leaves of A. ordosica, and the indices in enzymatic and non-enzymatic systems. Based on the statistics, we discussed the water physiology mechanism around the soil drought threshold. The results show that, around the soil drought threshold, besides absorbing and transporting water, the roots could serve as temporary water reservoirs that enable A. ordosica to continue to transport the SPAC water and survive severe drought. As drought becomes more severe, the activity of superoxide dismutase (SOD) and catalase (CAT) increases and they have significant correlations with the tissue water content. The activity of peroxidase (POD) decreases and it has no significant correlation with the tissue water content. During daytime, when temperature is high, the soluble sugar does not participate in the osmotic adjustment but eliminate the active oxygen free radicals. Thus, around the soil threshold of drought, A. ordosica maintains a physiological water metabolism by harmonizing water itself and eliminate the active oxygen and the free radicals by the joint efforts of enzymatic and nonenzymatic systems.

Pressure-volume curve (PV curve) technique is a major method for studying critical plant water potential and critical tissue water content when plasmolysis takes place. In the present study, a mathematical solution method is put forward to obtain parameters based on the PV curve. The calculated results for the parameters of Lolium perenne, Festuca arundinacea, Leymus chinensis and Stipa krylovii indicated that the mathematical solution method is convenient for actual research compared with the graphical method. Further analysis of the calculations suggested that drought resistance decreased in the following order: S. krylovii > F. arundinacea and L. chinensis > L. perenne.

We have proposed a novel optical sensor scheme based on chaotic correlation fiber loop ring down (CCFLRD). In contrast to the well-known FLRD spectroscopy, where pulsed laser is injected to fiber loop and ring down time is measured, the proposed CCFLRD uses a chaotic laser to drive a fiber loop and measures autocorrelation coefficient ring down time of chaotic laser. The fundamental difference enables us to avoid using long fiber loop as required in pulsed FLRD, and thus generates higher sensitivity. A strain sensor has been developed to validate the CCFLRD concept. Theoretical and experiment results demonstrate that the proposed method is able to enhance sensitivity by more than two orders of magnitude comparing to the existing FLRD method. We believe the proposed method could find great potential applications for chemical, medical, and physical sensing.

Among miRNAs, miR-155 is a known regulator of immune system. Accumulating studies have revealed the connections between miR-155 and activator protein 1 (AP-1)/nuclear factor (NF)-κB. However, miR-155*, a miR-155 paralog, has so far been less studied. Here we demonstrated that miR-155*, induced by lipopolysaccharide (LPS) in an AP-1/NF-κB dependent manner, played a positive feedback role in AP-1/NF-κB pathway via targeting interleukin-1 receptor-associated kinase M (IRAKM) and NF-κB inhibitor interacting Ras-like 1 (NKIRAS1) in trophoblasts. Our study further proved that miR-155*-targeted PTEN 3'-untranslated region (3'UTR) increased IRAKM and NKIRAS1 expression by competing for miR-155* binding, thereby suppressing AP-1/NF-κB activation induced by LPS.

Balanced immune responses are essential for the maintenance of successful pregnancy. Aberrant responses of immune system during pregnancy increase the risk of preeclampsia. Toll-like receptor 4 (TLR4) plays a crucial role in the activation of immune system at the maternal-fetal interface. This study aimed to generate a rat model of preeclampsia by lipopolysaccharide (LPS, a TLR4 agonist) administration on gestational day (GD) 5 as rats are subjected to placentation immediately after implantation between GDs 4 and 5, and to assess the contribution of TLR4 signaling to the development of preeclampsia. Single administration of 0.5 μg/kg LPS significantly increased blood pressure of pregnant rats since GD 6 (systolic blood pressure, 124.89 ± 1.79 mmHg versus 119.02 ± 1.80 mmHg, P < 0.05) and urinary protein level since GD 9 (2.02 ± 0.29 mg versus 1.11 ± 0.18 mg, P < 0.01), but barely affected blood pressure or proteinuria of virgin rats compared with those of saline-treated pregnant rats. This was accompanied with adverse pregnancy outcomes including fetal growth restriction. The expression of TLR4 and NF-κB p65 were both increased in the placenta but not the kidney from LPS-treated pregnant rats, with deficient trophoblast invasion and spiral artery remodeling. Furthermore, the levels of inflammatory cytokines were elevated systemically and locally in the placenta from pregnant rats treated with LPS. TLR4 signaling in the placenta was activated, to which that in the placenta of humans with preeclampsia changed similarly. In conclusion, LPS administration to pregnant rats in early pregnancy could elicit TLR4-mediated immune response at the maternal-fetal interface contributing to poor early placentation that may culminate in the preeclampsia-like syndrome.