Integral global sliding mode guidance for impact angle control

This Correspondence proposes a new guidance law based on integral sliding mode control (ISMC) technique for maneuvering target interception with impact angle constraint. A time-varying function weighted line-of-sight (LOS) error dynamics, representing the nominal guidance performance, is introduced first. The proposed guidance law is derived by utilizing ISMC to follow the desired error dynamics. The convergence of the guidance law developed is supported by Lyapunov stability. Simulations with extensive comparisons explicitly demonstrate the effectiveness of the proposed approach

A restricted projection problem for fractal sets in Rn\mathbb{R}^n

Let $\gamma: [-1, 1]\to \mathbb{R}^n$ be a smooth curve that is non-degenerate. Take $m\le n$ and a Borel set $E\subset [0, 1]^n$. We prove that the orthogonal projection of $E$ to the $m$-th order tangent space of $\gamma$ at $\theta\in [-1, 1]$ has Hausdorff dimension $\min\{m, \dim(E)\}$ for almost every $\theta\in [-1, 1]$.Comment: referee report incorporate

Composite finite‐time convergent guidance law for maneuvering targets with second‐order autopilot lag

This paper aims to develop a new finite‐time convergent guidance law for intercepting maneuvering targets accounting for second‐order autopilot lag. The guidance law is applied to guarantee that the line of sight (LOS) angular rate converges to zero in finite time and results in a direct interception. The effect of autopilot dynamics can be compensated based on the finite‐time backstepping control method. The time derivative of the virtual input is avoided, taking advantage of integral‐type Lyapunov functions. A finite‐time disturbance observer (FTDOB) is used to estimate the lumped uncertainties and high‐order derivatives to improve the robustness and accuracy of the guidance system. Finite‐time stability for the closed‐loop guidance system is analyzed using the Lyapunov function. Simulation results and comparisons are presented to illustrate the effectiveness of the guidance strategy

PTEN-regulated alternative splicing of FoxM1 affects tumor cell migration

Objective·To study the effect of phosphatase and tensin homolog on chromosome 10 (PTEN) on alternative splicing of forkhead box M1 (FoxM1), and its impact on tumor cell migration.Methods·PTEN was knocked down by short hairpin RNA (shRNA) in human embryonic kidney 293T cells, human prostate cancer DU145 cells, human colorectal adenocarcinoma RKO cells, and human colon cancer SW480 and SW620 cells. Specific primers were designed for FoxM1 and its subtypes FoxM1B and FoxM1C, and the mRNA expression levels of FoxM1B and FoxM1C were detected by quantitative real-time PCR (qRT-PCR). FoxM1B and FoxM1C were overexpressed in DU145 cells, and their effects on tumor cell migration were tested by Transwell assay and wound healing assay. Immunofluorescence and dual luciferase reporter gene assay were used to explore the potential mechanism of differential regulation of tumor cell migration by FoxM1B and FoxM1C.Results·① PTEN was knocked down in 293T, DU145, RKO, SW480, and SW620 cell lines. qRT-PCR results showed that compared with the control cells, the mRNA expression level of FoxM1B significantly increased in PTEN knockdown cells, while the mRNA expression level of FoxM1C decreased or remained unchanged. Knockdown of PTEN did not affect the transcription level of FoxM1, but caused the variable splicing of FoxM1 and promoted the generation of FoxM1B. ② Compared with the control cells, the number of DU145 cells migrating to the below chamber increased in the FoxM1B overexpression group (P=0.024), while the number of migrating DU145 cells in the FoxM1C overexpression group was lower (P=0.000). The healing ability of DU145 cells was significantly enhanced in the FoxM1B overexpression group (P=0.001), while the healing ability of DU145 cells was weakened in the FoxM1C overexpression group (P=0.021). Overall, FoxM1B and FoxM1C had opposite effects on tumor cell migration. FoxM1B promoted tumor cell migration, while FoxM1C inhibited tumor cell migration. ③ Neither FoxM1B nor FoxM1C overexpression could induce β-catenin to enter the nucleus. Dual luciferase reporter gene assay showed no difference in the transcriptional activity of FoxM1B and FoxM1C. The difference between FoxM1B and FoxM1C in the regulation of tumor metastasis was also not mediated by β-catenin translocation.Conclusion·Knockdown of PTEN regulates the alternative splicing of FoxM1, leading to increasing expression of transcript FoxM1B, which plays a positive role in tumor cell migration

Mixed Eucalyptus plantations in subtropical China enhance phosphorus accumulation and transformation in soil aggregates

IntroductionThe production of Eucalyptus, a principal economic tree genus in China, is faced with challenges related to soil phosphorus (P) limitations. In this study, we explore variations in phosphorus content, storage, and transformation in Eucalyptus forests. We hypothesize that mixed forests augment soil aggregate stability and P content and that microaggregates are pivotal in determining P differences between mixed and pure forests. Additionally, we posit that mixed forests foster P transformation, enhancing its efficacy in the soil. Current research on the distribution and transformation of soil total P (TP) and P fractions at the soil aggregate level is limited.MethodsIn this study, we selected soil from a Eucalyptus-Mytilaria laosensis Lecomte mixed forest, Eucalyptus-Erythrophleum fordii Oliv mixed forest, and pure Eucalyptus forest in Chongzuo County, Guangxi, China, as the research objects. Using a dry-sieving method, we divided the soil collected in situ from the 0–40 cm layer into aggregates of >2, 1–2, 0.25–1, and <0.25 mm particle sizes, measured the TP and P fractions (resin-extractable inorganic P, bicarbonate-extractable inorganic P, bicarbonate-extractable organic P, sodium hydroxide-extractable inorganic P, sodium hydroxide-extractable organic P, dilute hydrochloric acid-extractable P, concentrated hydrochloric acid extractable inorganic P, concentrated hydrochloric acid-extractable organic P and residue-P) in different aggregates, and used redundancy analysis and PLS SEM to reveal key factors affecting soil P accumulation and transformation.ResultsThe results showed that compared to pure Eucalyptus forests, mixed Eucalyptus forests significantly enhanced the stability of soil aggregates and the content and storage of phosphorus, especially the Eucalyptus-Mytilaria laosensis mixed forest. The content of total soil phosphorus and its fractions decreased with increasing aggregate particle size, while the opposite trend was observed for stored P, with aggregates <0.25 mm being the main fraction influencing soil phosphorus accumulation. The transformation process of P fractions was primarily constrained by dissolution rates, mineralization rates, biological activity, including the action of microbes, fungi, and plant–root interactions, and other factors.DiscussionMixed forests increased the transformation of phosphorus in soil aggregates, effectivel enhancing the availability of soil phosphorus. In summary, this study provides important evidence for the systematic management of subtropical artificia Eucalyptus forests and the sustainable utilization of soil resources

TiEV: The Tongji Intelligent Electric Vehicle in the Intelligent Vehicle Future Challenge of China

TiEV is an autonomous driving platform implemented by Tongji University of China. The vehicle is drive-by-wire and is fully powered by electricity. We devised the software system of TiEV from scratch, which is capable of driving the vehicle autonomously in urban paths as well as on fast express roads. We describe our whole system, especially novel modules of probabilistic perception fusion, incremental mapping, the 1st and the 2nd planning and the overall safety concern. TiEV finished 2016 and 2017 Intelligent Vehicle Future Challenge of China held at Changshu. We show our experiences on the development of autonomous vehicles and future trends