Robust adaptive constrained backstepping flight controller design for re-entry reusable launch vehicle under input constraint

A nonlinear constrained controller is designed for a reusable launch vehicle during re-entry phase in the presence of model uncertainty, external disturbance, and input constraint, via combining sliding mode control and adaptive backstepping control. Since the complex coupling between the translational and rotational dynamics of reusable launch vehicle, a control-oriented model derived from rotational dynamic is used for controller design. During the virtual control input design procedure, a dynamic robust term is utilized to compensate for the uncertainty. In addition, a filter is applied to handle “explosion of terms” problem during the actual control input design. To reduce the computational burden, adaptive law is used to evaluate the unknown norm bound of the lumped uncertainty. An auxiliary system is constructed to compensate for the input constraint effect. The stability of the closed-loop system is analyzed based on Lyapunov theory. Simulation results demonstrate the validity of the developed controller in providing stable tracking of the guidance command by numerical simulation on the 6-degree-of-freedom model of reusable launch vehicle

Spontaneous hepatic haemorrhage after caesarean section in a patient with uraemia and superimposed preeclampsia: a case report

Perinatal spontaneous hepatic haemorrhage is a very rare disease affecting pregnant women, particularly those on long-term dialysis, that has a high maternal and infant mortality rate. Most patients experience preeclampsia with haemolysis, elevated liver enzymes and low platelets syndrome. Here, the case of a 35-year-old multigravida patient with known chronic kidney disease and chronic hypertension with uraemia, who developed spontaneous hepatic haemorrhage after caesarean section, is described. The patient experienced sudden massive circulatory failure, but hemodynamics were temporarily stabilized after emergency surgery. Following transfer to the intensive care unit for continued treatment, her blood pressure and haemoglobin level continued to drop. Selective hepatic artery embolization was performed on day 2 after delivery, and her vital signs gradually stabilized. On day 30 after delivery, the patient was discharged in a stable condition. The newborn recovered after therapy in neonatal intensive care for 2 months. The present case suggests that, for perinatal spontaneous hepatic haemorrhage, timely and accurate diagnosis, multidisciplinary management and determining the therapeutic approach according to clinical symptoms are essential

Predicting the Potential Habitat Distribution of Relict Plant <i>Davidia involucrata</i> in China Based on the MaxEnt Model

Davidia involucrata Baill. 1871 (D. involucrata), as a tertiary relict plant unique to China, is a national Class I protected plant with high economic value. Oil extracted from its seeds and peels can be used for both consumption and industrial purposes. It has become a popular income-earning export tree in China because of its graceful posture and beautiful white bracts. Climate change affects the distribution of the species’ potential habitat areas. Thus, studying its natural distribution pattern and future potential habitat distribution changes has great significance for the sustainable resource utilization and biodiversity conservation of D. involucrata. Here, we employed the MaxEnt model and ArcGIS software to predict the current and future (the 2050s and 2070s) potential habitats of D. involucrata via 130 species distribution records and 37 environmental variables. Meanwhile, we used the jackknife method to assess the importance of environmental factors. Our results showed the following: (1) When the RM = 4 and FC = LQHPT, the MaxEnt model exhibited the lowest complexity and overfitting degree while achieving high model prediction accuracy. The area under the curve (AUC) value of the simulated training was 0.958, indicating an excellent forecast. (2) Under the current climate scenario, D. involucrata was mainly concentrated in eastern Sichuan, western Hubei, northern Guizhou, and northwestern Hunan, with an area of 98.02 × 104 km2. (3) The precipitation in the warmest quarter (Bio18, 30%), mean temperature in the driest quarter (Bio9, 24.4%), annual mean radiation (Bio20, 14.6%), and elevation (ele, 12.7%) were the main environmental factors affecting its habitat distribution; the t contribution was 82.1%. (4) Under different future climate scenarios, the potential habitat area of D. involucrata decreased overall. Compared with the current climate scenario, the areas of potential habitats gradually decreased in both the 2050s and 2070s under the ssp126 and ssp585 climate scenarios but decreased in the 2050s and then increased in the 2070s under the ssp370 climate scenario. Therefore, it is of great significance to track and monitor the existing population or community on the basis of the possible changes in its distribution area. Moreover, the artificial breeding of its seedlings should be considered in the future to improve the quality of its germplasm resources. In summary, our findings can provide a scientific understanding of D. involucrata distribution in China and are conducive to conservation and utilization

Puerarin-V Improve Mitochondrial Respiration and Cardiac Function in a Rat Model of Diabetic Cardiomyopathy via Inhibiting Pyroptosis Pathway through P2X7 Receptors

There is a new form of puerarin, puerarin-V, that has recently been developed, and it is unclear whether puerarin-V has a cardioprotective effect on diabetic cardiomyopathy (DCM). Here, we determined whether puerarin-V had any beneficial influence on the pathophysiology of DCM and explored its possible mechanisms. By injecting 30 mg/kg of STZ intraperitoneally, diabetes was induced in rats. After a week of stability, the rats were injected subcutaneously with ISO (5 mg/kg). We randomly assigned the rats to eight groups: (1) control; (2) model; (3) metformin; (4–6) puerarin-V at different doses; (7) puerarin (API); (8) puerarin injection. DCM rats were found to have severe cardiac insufficiency (arrythmia, decreased LVdP/dt, and increased E/A ratio). In addition, cardiac injury biomarkers (cTn-T, NT-proBNP, AST, LDH, and CK-MB), inflammatory cytokines (IL-1β, IL-18, IL-6, and TNF-α), and oxidative damage markers (MDA, SOD and GSH) were markedly increased. Treatment with puerarin-V positively adjusts these parameters mentioned above by improving cardiac function and mitochondrial respiration, suppressing myocardial inflammation, and maintaining the structural integrity of the cardiac muscle. Moreover, treatment with puerarin-V inhibits the P2X7 receptor-mediated pyroptosis pathway that was upregulated in diabetic hearts. Given these results, the current study lends credence to the idea that puerarin-V can reduce myocardial damage in DCM rats. Furthermore, it was found that the effect of puerarin-V in diabetic cardiomyopathy is better than the API, the puerarin injection, and metformin. Collectively, our research provides a new therapeutic option for the treatment of DCM in clinic

The effects of fertility and synchronization variation on seed production in two Chinese fir clonal seed orchards

Abstract Variations in fertility and synchronization information is fundamental to seed orchard management. Our objective was to determine clonal variation and stability in strobili production, phenology, synchronization, and seed production in two generation clonal seed orchards (CSO) of Chinese fir. The number of female and male strobili and the phenology of 42 clones in both the 2.0- and 2.5-generation clonal seed orchards were investigated and recorded to calculate the variation and stability of fertility and synchronization. In both seed orchards, an obvious variation in gamete contribution was found among clones, indicating deviation from random mating. Female receptivity was in the pollen shedding stage, which is favorable to pollination. However, low synchronization (mean POij = 0.283) between clones indicated low overlap between female receptivity and pollen shedding. A higher POij value within clones than within outcrossing combinations indicated a high risk of selfing in two seed orchards, particularly for early- and late-flowering clones. The number of female strobili and POij (as female) significantly influence seed production. Overall, fertility and synchronization variation had notable consequences for seed production. Scientific genetic management is indispensable for promoting fertility uniformity and synchronization to obtain maximal genetic gain

Integrative Metabolomic and Transcriptomic Analysis Reveals the Mechanism of Specific Color Formation in <i>Phoebe zhennan</i> Heartwood

Nanmu (Phoebe zhennan) is an extremely valuable tree plant that is the main source of famous “golden-thread nanmu” wood. The potential metabolites and gene regulation mechanisms involved in golden thread formation are poorly understood, even though the color change from sapwood to heartwood has been investigated in several tree plants. Here, five radial tissues from sapwood to heartwood were compared via integrative metabolomic and transcriptomic analysis to reveal the secondary metabolites and molecular mechanisms involved in golden thread formation. During heartwood formation, gradual starch grain loss is accompanied by the cell lumen deposition of lipids and color-related extractives. Extractives of 20 phenylpropanoids accumulated in heartwood, including cinnamic acids and derivatives, coumarin acid derivatives, and flavonoids, which were identified as being closely related to the golden thread. Phenylpropanoids co-occurring with abundant accumulated metabolites of prenol lipids, fatty acyls, steroids, and steroid derivatives may greatly contribute to the characteristics of golden thread formation. Additionally, the expression of nine genes whose products catalyze phenylpropanoid and flavonoids biosynthesis was upregulated in the transition zone, then accumulated and used to color the heartwood. The expression levels of transcription factors (e.g., MYB, bHLH, and WRKY) that act as the major regulatory factors in the synthesis and deposition of phenylpropanoid and flavonoids responsible for golden thread formation were also higher than in sapwood. Our results not only explain golden thread formation in nanmu, but also broaden current knowledge of special wood color formation mechanisms. This work provides a framework for future research focused on improving wood color