Trajectory Estimation of Aircraft in a Double-Satellite Passive Positioning System with the Adjoint Method

A double-satellite passive positioning system is constructed based on the theory of space geometry, where two observation coordinate systems and a fundamental coordinate system exist. In each observation coordinate system, there exists a ray from the observation satellite to the aircraft. One difficulty lies in that these two rays may not intersect due to the existence of various errors. Under this situation, this work assumes that the middle point of common perpendicular between two rays is the actual position of aircraft. Based on the theory of space geometry, the coordinates of aircraft in the fundamental coordinate system can be determined. A dynamic model with the adjoint method is developed to estimate the trajectory of aircraft during the process of rocket propulsion. By assimilating observations, the trajectory of aircraft can be calculated. Numerical experiments are designed to validate the reasonability and feasibility of this model. Simulated results indicate that even by assimilating a small number of observations, the trajectory of aircraft can be estimated. In addition, the trajectory estimation can become more accurate when more observations are assimilated to the model

Predicting human microRNA precursors based on an optimized feature subset generated by GA–SVM

AbstractMicroRNAs (miRNAs) are non-coding RNAs that play important roles in post-transcriptional regulation. Identification of miRNAs is crucial to understanding their biological mechanism. Recently, machine-learning approaches have been employed to predict miRNA precursors (pre-miRNAs). However, features used are divergent and consequently induce different performance. Thus, feature selection is critical for pre-miRNA prediction. We generated an optimized feature subset including 13 features using a hybrid of genetic algorithm and support vector machine (GA–SVM). Based on SVM, the classification performance of the optimized feature subset is much higher than that of the two feature sets used in microPred and miPred by five-fold cross-validation. Finally, we constructed the classifier miR-SF to predict the most recently identified human pre-miRNAs in miRBase (version 16). Compared with microPred and miPred, miR-SF achieved much higher classification performance. Accuracies were 93.97%, 86.21% and 64.66% for miR-SF, microPred and miPred, respectively. Thus, miR-SF is effective for identifying pre-miRNAs

Defect-Rich Heterogeneous MoS2/rGO/NiS Nanocomposite for Efficient pH-Universal Hydrogen Evolution

Molybdenum disulfide (MoS2) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS2-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS2, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH)2 nanowires as the nickel source. The MoS2/rGO/NiS-5 of optimal formulation in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm−2 (denoted as η10), respectively. The excellent HER performance of the MoS2/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS2/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst

Design and Evaluation the Anti-Wear Property of Inorganic Fullerene Tungsten Disulfide as Additive in PAO6 Oil

Inorganic fullerene-like tungsten disulfide particles have been proved to have good anti-friction and anti-wear properties as lubricating materials. As far as we know, however, when it is used as a lubricant additive, its behavior and action mechanism in the friction process are rarely studied. Herein, IF–WS2 particles were synthesized by a Chemical Vapor Deposition (CVD) method. The effect of IF–WS2 particle concentrations in the PAO6 oil on the tribological behaviors was investigated with a four-ball wear machine at both 75 and 100 °C. Additionally, the analyzed morphology and composition of nanomaterials and worn surfaces were analyzed by Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The friction behavior in actual working conditions was studied by a wear testing machine. The experimental results show that compared with the original PAO6 oil, at a dispersion of 0.25 wt in PAO6 oil, the IF–WS2 particles showed the best performance in terms of coefficient of friction, wear scar diameter and wear mass, which significantly reduced by 27, 43 and 87, respectively. At the same time, in the process of friction, it was found that IF–WS2 particles accumulated in the depressions to fill the scratches, and adsorption films and chemical films, including FeS2, WS2 and WO3, were formed on the worn surfaces to avoid the direct contact among the friction pairs more effectively, resulting in the improved anti-wear performances. Additionally, the addition of IF–WS2 particles effectively delayed the rise of lubricating oil temperature. In addition, dispersant span 80 can effectively improve the dispersion and stability of IF–WS2 in PAO6. This work provides us for understanding the effective lubrication mechanism of IF–WS2 particles in more detail and having a new acknowledge of the comprehensive performance of IF–WS2/PAO6 oil

Identifying potential anti-COVID-19 pharmacological components of traditional Chinese medicine Lianhuaqingwen capsule based on human exposure and ACE2 biochromatography screening

药学院吴彩胜副教授联合海军军医大学柴逸峰教授团队在连花清瘟胶囊防治新冠肺炎的药理活性成分和机制研究方面取得新进展，这项研究基于HRMS和智能非靶向数据挖掘技术，全面分析了对多次给药后人血浆和尿液中的连花清瘟胶囊成分，合成了全新的ACE2生物色谱固定相，筛选出连花清瘟胶囊提取物和人尿液样品潜在的ACE2靶向成分。这项研究是连花清瘟胶囊的人体暴露信息的首次报道，为其在抗COVID-19的药理活性成分和作用机制研究提供了化学和药理学理论依据。本研究证明基于人体暴露的研究策略可用于高效的发掘中草药中的药效活性物质。【Abstract】Lianhuaqingwen (LHQW) capsule, a herb medicine product, has been clinically proved to be effective in coronavirus disease 2019 (COVID-19) pneumonia treatment. However, human exposure to LHQW components and their pharmacological effects remain largely unknown. Hence, this study aimed to determine human exposure to LHQW components and their anti-COVID-19 pharmacological activities. Analysis of LHQW component profiles in human plasma and urine after repeated therapeutic dosing was conducted using a combination of HRMS and an untargeted data-mining approach, leading to detection of 132 LHQW prototype and metabolite components, which were absorbed via the gastrointestinal tract and formed via biotransformation in human, respectively. Together with data from screening by comprehensive 2D angiotensin-converting enzyme 2 (ACE2) biochromatography, 8 components in LHQW that were exposed to human and had potential ACE2 targeting ability were identified for further pharmacodynamic evaluation. Results show that rhein, forsythoside A, forsythoside I, neochlorogenic acid and its isomers exhibited high inhibitory effect on ACE2. For the first time, this study provides chemical and biochemical evidence for exploring molecular mechanisms of therapeutic effects of LHQW capsule for the treatment of COVID-19 patients based on the components exposed to human. It also demonstrates the utility of the human exposure-based approach to identify pharmaceutically active components in Chinese herb medicines.The authors would like to thank Prof. Chuan Li in Shanghai Institute of Materia Medica, Chinese Academy of Sciences (Shanghai, China) to provide biological samples and technical guidance. This research was supported by Natural Science Foundation of China, China, (Grant Nos. 81773688, U1903119, 81973291, and 81973275); Zhejiang University Special Scientific Research Fund for COVID-19 Prevention and Control, China; “Phospherus” Project of Shanghai Science and Technology Committee, China, (Grant Nos. 19QA1411500); National Major Scientific and Technological Special Project for "Significant New Drugs Development", China, (Grant No. 2020ZX09201005)

Estimation of Oceanic Eddy Viscosity Profile and Wind Stress Drag Coefficient Using Adjoint Method

Adjoint method is used to assimilate pseudoobservations to simultaneously estimate the OEVP and the WSDC in an oceanic Ekman layer model. Five groups of experiments are designed to investigate the influences that the optimization algorithms, step-length, inverse integral time of the adjoint model, prescribed vertical distribution of eddy viscosity, and regularization parameter exert on the inversion results. Experimental results show that the best estimation results are obtained with the GD algorithm; the best estimation results are obtained when the step-length is equal to 1 in Group 2; in Group 3, 8 days of inverse integral time yields the best estimation results, and good assimilation efficiency is achieved by increasing iteration steps when the inverse integral time is reduced; in Group 4, the OEVP can be estimated for some specific distributions; however, when the VEVCs increase along with the depth at the bottom of water, the estimation results are relatively poor. For this problem, we use extrapolation method to deal with the VEVCs in layers in which the estimation results are poor; the regularization method with appropriate regularization parameter can indeed improve the experiment result to some extent. In all experiments in Groups 2-3, the WSDCs are inverted successfully within 100 iterations

Estimation of Open Boundary Conditions Based on an Isopycnic-Coordinate Internal Tidal Model with Adjoint Assimilation Method

The isopycnic-coordinate internal tidal model with adjoint assimilation method is developed into a three-layer version. Two groups of ideal experiments are carried out in order to investigate the estimation of spatially varying open boundary conditions (OBCs). In group 1, different independent point schemes (IPSs) are used to invert 6 kinds of prescribed distributions of OBCs. Results show that, after assimilation, the cost functions and their gradient norms are reduced by about 2 orders of magnitude and by about 1 order of magnitude, respectively; the mean absolute errors (MAEs) in OBCs and the vector differences of horizontal current are reduced by 1 order of magnitude and by more than 23.53% compared with the values before assimilation, respectively. The results demonstrate that the three-layered model has a good ability in estimating the spatially varying OBCs; the use of IPSs can effectively improve the estimation precision; fewer independent points are feasible when the distribution is simpler, and appropriately more independent points are required when the distribution is more complex. In group 2, by using the optimal IPSs in group 1, the model is also able to successfully invert the OBCs on a real topography in the Luzon Strait area. The results are important to the study of the internal tide in the South China Sea

Estimation of Bottom Friction Coefficients Based on an Isopycnic-Coordinate Internal Tidal Model with Adjoint Method

Based on an isopycnic-coordinate internal tidal model with the adjoint method, three groups of ideal experiments are carried out in order to investigate the estimation of spatially varying bottom friction coefficients (BFCs). In group 1, five values of distance between independent points (DIP) are used to invert the BFCs with the distribution of conical surface. Results show that the BFCs can be inverted successfully with independent point scheme and the strategy with a DIP of 50′ can yield the best results. In group 2, five values of interpolation radius (IR) are used to invert the BFCs with the distribution of conical surface. Results show that the strategy with an IR of 1.9 times of DIP can yield the best results. Based on the results of the first two groups, group 3 adopts the optimal DIP and IR to estimate 4 kinds of spatially varying BFCs. The results indicate that the isopycnic-coordinate internal tidal model with the adjoint method has a good ability to estimate the spatially varying BFCs; the inversion results of the BFCs with the distribution of revolution paraboloid are better than those with the distribution of conical surface

A circRNA therapy based on Rnf103 to inhibit Vibrio anguillarum infection

Summary: The losses caused by Vibrio infections in the aquaculture industry are challenging to quantify. In the face of antibiotic resistance, a natural and environmentally friendly alternative is urgently needed. In this study, we identify E3 ubiquitin-protein ligase RNF103 (rnf103) as a crucial target involved in immune evasion by Vibrio anguillarum. Our research demonstrates that Rnf103 promotes immune escape by inhibiting Traf6. Interestingly, we discover a circular RNA (circRNA), circRnf103, formed by reverse splicing of the Rnf103 gene. Predictive analysis and experimentation reveal that circRnf103 encodes Rnf103-177aa, a protein that competes with Rnf103 and binds to Traf6, preventing its degradation. Notably, circRnf103 therapy induces Rnf103-177aa protein production in zebrafish. In zebrafish models, circRnf103 exhibits significant effectiveness in treating V. anguillarum infections, reducing organ burden. These findings highlight the potential of circRNA therapy as a natural and innovative approach to combat infectious diseases sustainably, particularly in aquaculture and environmental management

Three-Dimensional Flower-like Fe, C-Doped-MoS2/Ni3S2 Heterostructures Spheres for Accelerating Electrocatalytic Oxygen and Hydrogen Evolution

The exploration of high-efficiency bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has long been challenging. The rational design of a catalyst by constructing heterostructures and a doping element are possibly expected to achieve it. Herein, the utilization of flower-like Fe/C-doped-MoS2/Ni3S2-450 spherical structural materials for electrocatalytic HER and OER is introduced in this study. The carboxyferrocene-incorporated molybdenum sulfide/nickel sulfide (MoySx/NiS) nanostructures were prepared by solvothermal method. After annealing, the iron and carbon elements derived from ferrocenecarboxylic acid enhanced the electrical transport performance and provided rich electronic sites for HER and OER in alkaline media. Specifically, the optimized flower-like Fe/C-doped-MoS2/Ni3S2-450 exhibited efficient bifunctional performance in alkaline electrolyte, with low overpotentials of 188 and 270 mV required to deliver a current density of 10 mA cm−2 for HER and OER, respectively. This work provides valuable insights for the rational design of energy storage and conversion materials by the incorporation of transition metal and carbon elements into metal sulfide structures utilizing metallocene