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This paper presents the solution approach developed by the team "theAntipodes" for the 11th Global Trajectory Optimization Competition (GTOC11). The approach consists of four main blocks: 1) mothership chain generation, 2) rendezvous table generation, 3) the dispatcher, and 4) the refinement. Blocks 1 and 3 are purely combinatorial optimization problems that select the asteroids to visit and allocate them to the Dyson ring stations. The rendezvous table generation involves interpolating time-optimal transfers to find all transfer opportunities between selected asteroids and the ring stations. The dispatcher uses the data stored in the table and allocates the asteroids to the Dyson ring stations optimally. The refinement ensures each rendezvous trajectory meets the problem accuracy constraints and introduces deep-space maneuvers to the mothership transfers. We provide the details of our solution that, with a score of 5,992, was worth 3rd place., 17 pages, 11 figures

Background Hepatocellular carcinoma (HCC) is recognized as a leading cause of cancer-associated fatality worldwide. Our study here aimed to probe the mechanism by which exosomes secreted by CSQT-2, an HCC cell line, affected the progression of HCC. Methods Exosomes were extracted from CSQT-2 cells. Colony formation, Transwell, sphere formation and flow cytometric analyses were applied to assess cell biological activities. Microarray analysis detected the change of microRNA (miRNA) expression after exosome treatment, followed by RT-qPCR validation. Luciferase reporter was applied to detect the binding between SIK1 and miR-25. Xenograft studies in nude mice manifested tumor growth and metastatic ability of miR-25 and SIK1. Results The exosome treatment enhanced cell malignant phenotype in vitro and tumor growth and liver and lung metastases in vivo. The exosomes elevated miR-25 expression in HCC cells. miR-25 targeted SIK1 which was decreased in the exosomes-treated cells. miR-25 inhibitor reduced cell malignant phenotype and attenuated tumorigenesis and metastasis in vivo. SIK1 silencing reversed the effect of miR-25 inhibitor. The exosome treatment potentiated the Wnt/β-catenin pathway in cells, whereas miR-25 inhibitor blunted the pathway activity. Conclusion MiR-25 shuttled through CSQT-2-derived exosomes promoted the development of HCC by reducing SIK1 expression and potentiating the Wnt/β-catenin pathway.

Opioid use disorder is a chronic brain disease influenced by genetic and epigenetic factors, accounting for approximately 50% of the liability. Adrenergic signaling is involved in opioid use disorder. To demonstrate the associations between methylation alterations in the alpha-1-adrenergic receptor (ADRA1A) gene and opioid use disorder, in the present study, we first examined and compared the methylation levels of 97 CpG sites in the promoter region of the ADRA1A gene in the peripheral blood in 120 patients with heroin use disorder and 111 healthy controls. Correlations between methylation levels and duration of heroin/methadone use were then analyzed. Finally, the predicted binding transcription factors (TFs) and their target sequences in the promoter region of the ADRA1A gene, which include the selected CpG sites, were screened in the JASPAR database. Our results demonstrated that hypermethylation in the promoter region of the ADRA1A gene in the blood was associated with opioid use disorder. Correlations between methylation levels of several CpG sites and duration of heroin/methadone use were observed. TFs TFAP2A and RUNX1 were predicted to bind to the target sequences, which include the CpG sites selected in the current study, in the promoter region of the ADRA1A gene. Our findings further extend the associations between methylation alterations in the ADRA1A gene and opioid use disorder potentially through mechanisms of gene expression regulations in the ADRA1A gene.

Due to the strong nonlinear perturbations near the libration points, the continuous low-thrust technique has many potential applications in stationkeeping relative motions. The Hamiltonian structure-preserving (HSP) control is employed in this paper to stabilize formation flying on quasi-periodic orbits near L L 1 of the restricted Sun–Earth–Moon–spacecraft system. In the bi-circular model (BCM), a multiple shooting corrector is developed to refine quasi-periodic orbits as the chief spacecraft's reference trajectories. The linearized variation equation in BCM is used to design the stationkeeping control. A HSP controller is constructed to change the topology of the equilibrium from hyperbolic to elliptic using only relative position feedbacks consisting of stable, unstable and center manifolds. The critical control gains for transient and long-term stabilities are presented to guide the selection of control gains.

Currently, a tremendous amount of space debris in Earth’s orbit imperils operational spacecraft. It is essential to undertake risk assessments of collisions and predict dangerous encounters in space. However, collision predictions for an enormous amount of space debris give rise to large-scale computations. In this paper, a parallel algorithm is established on the Compute Unified Device Architecture (CUDA) platform of NVIDIA Corporation for collision prediction. According to the parallel structure of NVIDIA graphics processors, a block decomposition strategy is adopted in the algorithm. Space debris is divided into batches, and the computation and data transfer operations of adjacent batches overlap. As a consequence, the latency to access shared memory during the entire computing process is significantly reduced, and a higher computing speed is reached. Theoretically, a simulation of collision prediction for space debris of any amount and for any time span can be executed. To verify this algorithm, a simulation example including 1382 pieces of debris, whose operational time scales vary from 1 min to 3 days, is conducted on Tesla C2075 of NVIDIA. The simulation results demonstrate that with the same computational accuracy as that of a CPU, the computing speed of the parallel algorithm on a GPU is 30 times that on a CPU. Based on this algorithm, collision prediction of over 150 Chinese spacecraft for a time span of 3 days can be completed in less than 3 h on a single computer, which meets the timeliness requirement of the initial screening task. Furthermore, the algorithm can be adapted for multiple tasks, including particle filtration, constellation design, and Monte-Carlo simulation of an orbital computation.

Accumulating studies assessing the impacts of hot spot mutations on conventional interferon (IFN) efficacy come to discrepant conclusions; studies regarding the mutations in S and RT regions are also unclear. The present study aimed to evaluate the impacts of HBV mutations on the efficacy of conventional IFN.A total of 126 patients who received conventional IFN treatment for 48 weeks were enrolled. Biochemical and serological parameters were routinely tested. The sequences of HBV from 78 serum samples were amplified by nested-PCR; mutations were identified with sequence scanner V1.0 after ABI 3730xl direct sequencing, HBV genotypes were determined according to RT gene sequences utilizing NCBI Genotyping Tool which was based on phylogenetic analysis.The baseline DNA levels of virological response (VR) group were significantly lower than those of no VR group [7.13+/-0.76 vs 7.69+/-0.56 lg (copies/mL), P=0.001]. The baseline ALT levels were significantly higher in the HBeAg clearance group (204.72+/-88.65 vs 162.80+/-85.81 IU/L, P0.05) and HBeAg seroconversion group (204.89+/-95.68 vs 166.75+/-84.43 IU/L, P0.05). Females and lower BMI levels (20.01+/-2.33 vs 21.65+/-3.66 kg/m2, P0.05) were prone to acquired biochemical response (BR). PC-W28STOP (ntG1896A) was significantly higher in the combined response (CR) group than that in the no CR group (91.7% vs 39.7%, P=0.001). Multivariate logistic regression analysis showed that baseline DNA, PC-P159T (ntC2288A), BCP-N118T (ntA1726C) and BCP-L134L (ntA1775C/G/T) influenced VR independently. PC-G182C (ntG2357T), PC-S64A/T (ntT2003G/A) and BMI were independent influence factors for HBeAg clearance, HBeAg seroconversion and BR, respectively. The new predicting model concluded that baseline DNA and new mutations for VR were established successfully, and ROC analysis showed that AUC was 0.842 (P0.001) with a sensitivity of 0.652 and a specificity of 0.933.PC-P159T (ntC2288A), BCP-N118T (ntA1726C), BCP-L134L (ntA1775C/G/T), PC-G182C (ntG2357T) and PC-S64A/T (ntT2003G/A) were novel identified mutations that impacted IFN therapeutic efficacy. These novel mutations could serve as important predictors before conventional IFN treatment.

An integrated algorithm to design the optimal ascent trajectory of a target Sun-synchronous orbit (SSO) for small-lift launch vehicles is studied in this paper. A general problem description is provided, including the specific pitch law designed for an ascent trajectory to SSO and the definitions of design variables and equality/inequality constraints. Then an integrated optimization scheme is introduced to solve this problem. In order to improve its efficiency, a preliminary determination method is to analytically generate two sensitive design variables related with the coast arc. With the help of the two design variables, an initial combination of design variables can be obtained by solving separately the optimization problems of two powered phases. Based on the predetermination method, an efficient integrated algorithm using hierarchical optimization is proposed. A simulation based on a type of small-lift Electron Rocket and Rutherford engine is performed using this hierarchical optimization algorithm and the feasibility and efficiency of this algorithm is evaluated. These systematic investigations on all the possible injected orbits give a full detail of launching capability for Electron Rocket.

In order to evaluate the highway maintenance enterprise synthetically and quantificationally, a safety evaluation indicator is established according to the impact conservation production safety factors in this paper. It can help the conservation and management departments to keep abreast of the conservation highway enterprise safety production dynamic and make the targeted safety measures. Lee scale is designed for expert scoring. Analytic hierarchy process (AHP) is adopted to select it. The indicator weights are ensured by AHP so as to establish highway maintenance safety production comprehensive evaluation system. By verifying the evaluated cases, this method can effectively improve the effectiveness and accuracy of the highway safety production. It has great significance for accelerating highway maintenance safety management system.

Close-proximity Coulomb formation flying offers attractive prospects in multiple astronautical missions. To achieve a deeper understanding of the dynamical structures of Coulomb formations, in this paper, an eight-charge symmetric configuration of Coulomb formation is presented and its dynamics is analyzed by center manifold reduction and Poincare maps. The Hamiltonian equations of motion for the Coulomb formation are derived on the basis of Clohessy–Wiltshire equations. Equilibrium configurations of the Coulomb formation and their corresponding linearized vector fields in different charging scenarios are studied. Nonlinear dynamics near the equilibrium points is investigated with center manifold reduction based on Lie series method. Poincare maps are employed to describe the bounded motions of the reduced Hamiltonian system. Numerical results indicate that there exist two families of Lyapunov periodic orbits, 1:1 and 1:2 resonance halo orbits, chaotic orbits, and two-dimensional invariant tori and the center manifold is capable of capturing all the dynamics in different charging scenarios.

This paper investigates the Cauchy problem for an isentropic magnetogasdynamic system. Under certain reasonable hypotheses on the initial data, we obtain the global existence and uniqueness of the C 1 solution to the system. Meanwhile, when the hypotheses on the initial data do not hold, we obtain the blow-up phenomena of the C 1 solution to the system. The bounds of the solution are shown to depend on the parameter ν, which characterizes a one-dimensional plane flow ( ν = 0 ) or a three-dimensional cylindrically symmetric flow ( ν = 1 ); it is shown that the existence of the finite time singularity is significantly influenced by the magnetic field strength present in the flow along with the initial data.

The exact controllability and observability for a heat equation with hyperbolic memory kernel in anisotropic and nonhomogeneous media are considered. Due to the appearance of such a kind of memory, the speed of propagation for solutions to the heat equation is finite and the corresponding controllability property has a certain nature similar to hyperbolic equations, and is significantly different from that of the usual parabolic equations. By means of Carleman estimate, we establish a positive controllability and observability result under some geometric condition. On the other hand, by a careful construction of highly concentrated approximate solutions to hyperbolic equations with memory, we present a negative controllability and observability result when the geometric condition is not satisfied.

In this Note, a weighted identity for partial differential operators of second order is established. As its applications, one may deduce all the known controllability/observability results for the parabolic, hyperbolic, Schrodinger and plate equations that are derived via Carleman estimate. Meanwhile, a new controllability/observability result is presented for the parabolic equations with a complex principal part. To cite this article: X. Fu, C. R. Acad. Sci. Paris, Ser. I 342 (2006).

A novel random mutagenesis strategy was developed by combining sodium bisulfite modification with polymerase chain reaction (PCR). This method introduced the predominant substitution of GC to AT, meaning that it was more suitable for mutagenesis of GC-rich genes and helped to decrease the GC content of target DNA. Mutation efficiency correlated with modification time and different mutation frequency could easily be obtained by controlling modification time. The results indicated that this method could yield a desired and adequate frequency of random mutation to the DNA of interest, especially GC-rich genes, and provided a powerful tool for directed molecular evolution.