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The objective of this study was to investigate the absorption behavior of chikusetsusaponin IVa (CHS-IVa) in the rat intestine using single-pass intestinal perfusion (SPIP) and to classify CHS-IVa into the biopharmaceutics classification system (BCS). The equilibrium solubility of CHS-IVa was determined by the shaker method. The absorption mechanism of CHS-IVa in the intestine was studied by comparing the Peff of different concentrations of CHS-IVa. The intestinal site dependence of CHS-IVa absorption was studied by comparing the Peff of the same concentration of CHS-IVa in different intestinal segments. The relationship between CHS-IVa and intestinal efflux protein was studied by perfusion with an efflux protein inhibitor. The permeability of CHS-IVa was investigated by comparing the Peff of CHS-IVa and the reported value. The solubility of CHS-IVa over the pH range 1.0-7.5 was 14.4 ± 0.29 to 16.9 ± 0.34 mg/ml. The Peff of CHS-IVa in the duodenum was 1.76 × 10-3 to 2.00 × 10-3 cm/min. The Peff of CHS-IVa in the jejunum was 1.26 × 10-3 to 1.39 × 10-3 cm/min. The Peff of CHS-IVa in the ileum was 1.25 × 10-3 to 1.31 × 10-3 cm/min. The Peff of CHS-IVa in the colon was 1.02 × 10-3 to 1.08 × 10-3 cm/min. There was no statistical difference of the Peff in the four segments at different CHS-IVa concentrations. The Peff of CHS-IVa (0.07, 0.7 and 7.0 mg/ml) were all notably smaller than the reported Peff (3.00 × 10-3 cm/min) in the jejunum. The Peff of CHS-IVa was not influenced by verapamil (P-gp inhibitor), indomethacin (MRP inhibitor) and pantoprazole (BCRP inhibitor). CHS-IVa was classified as high solubility, low permeability and BCS III. The main absorptive tracts were the upper intestinal tracts and the rank order of intestinal permeability was duodenum > jejunum ≈ ileum > colon. The transport mechanism of CHS-IVa in all intestinal segments might be primarily passive transport. CHS-IVa was not a substrate of P-gp, MRP and BCRP.

The effect of sodium salicylate (NaSal) on the spherical-to-threadlike micelle shape transition in 3-hexadecyloxy-2-hydroxy-propyl trimethyl ammonium bromide (R16HTAB) solution was studied using mo...

A bio-nanocluster (Fe

Obstacle avoidance is crucial for autonomous surface vehicles (ASVs) in the sea because rescue is extremely difficult there. OceanVoy, a sailboat toward long range energy-saving voyage, has to overcome the dual challenges, i.e. from the environmental interference and its low mobility preventing from precise obstacle avoidance. We propose a control scheme based on real-time collision risk assessment and a hybrid propulsion system to enhance safety of OceanVoy. A novel sailboat safety zone (SSZ) has been designed to warn the potential collision during its sailing. Both intrinsic characteristics of OceanVoy and environmental factors have been considered in SSZ. We use lateral and axial thrusters to provide emergency propulsion. A collision avoidance algorithm is executed to coordinate motors in rudder, sail and thrusters based on SSZ. Both simulation and experiments have been conducted and the results have validated our system and collision avoidance scheme.

Automatic latching for charging in a disturbed environment for Unmanned Surface Vehicle (USVs) is always a challenging problem. In this paper, we propose a two-stage automatic latching system for USVs charging in berth. In Stage I, a vision-guided algorithm is developed to calculate an optimal latching position for charging. In Stage II, a novel latching mechanism is designed to compensate the movement misalignments from the water disturbance. A set of experiments have been conducted in real-world environments. The results show the latching success rate has been improved from 40% to 73.3% in the best cases with our proposed system. Furthermore, the vision-guided algorithm provides a methodology to optimize the design radius of the latching mechanism with respect to different disturbance levels accordingly. Outdoor experiments have validated the efficiency of our proposed automatic latching system. The proposed system improves the autonomy intelligence of the USVs and provides great benefits for practical applications.

Traditional solar trackers often adopt motors to automatically adjust the attitude of the solar panels towards the sun for maximum power efficiency. In this paper, a novel design of solar tracker for the ocean environment is introduced. Utilizing the fluctuations due to the waves, electromagnetic brakes are utilized instead of motors to adjust the attitude of the solar panels. Compared with the traditional solar trackers, the proposed one is simpler in hardware while the harvesting efficiency is similar. The desired attitude is calculated out of the local location and time. Then based on the dynamic model of the system, the angular acceleration of the solar panels is estimated and a control algorithm is proposed to decide the release and lock states of the brakes. In such a manner, the adjustment of the attitude of the solar panels can be achieved by using two brakes only. Experiments are conducted to validate the acceleration estimator and the dynamic model. At last, the feasibility of the proposed solar tracker is tested on the real water surface. The results show that the system is able to adjust 40° in two dimensions within 28 seconds.

The new era with prosperous artificial intelligence (AI) and robotics technology is reshaping the materials discovery process in a more radical fashion. Here we present authentic intelligent robotics for chemistry (AIR-Chem), integrated with technological innovations in the AI and robotics fields, functionalized with modules including gradient descent-based optimization frameworks, multiple external field modulations, a real-time computer vision (CV) system, and automated guided vehicle (AGV) parts. AIR-Chem is portable and remotely controllable by cloud computing. AIR-Chem can learn the parametric procedures for given targets and carry on laboratory operations in standalone mode, with high reproducibility, precision, and availability for knowledge regeneration. Moreover, an improved nucleation theory of size focusing on inorganic perovskite quantum dots (IPQDs) is theoretically proposed and experimentally testified to by AIR-Chem. This work aims to boost the process of an unmanned chemistry laboratory from the synthesis of chemical materials to the analysis of physical chemical properties, and it provides a vivid demonstration for future chemistry reshaped by AI and robotics technology.

A bio-nanocluster (Fe3O4@bacteria) was prepared by simply mixture using the bacterial suspension and Fe3O4 nanoclusters to remove Congo red (CR) contamination from water resources. The bio-nanocluster was characterized by SEM, TEM and XPS. Adsorption efficiency, adsorption process and adsorption mechanism were comprehensively investigated. The maximum adsorption capacity (Qm) of CR dye onto the Fe3O4@bacteria peaked at 320.1 mg/g, which was 2.88 times that of Fe3O4 under the same condition. Based on the equilibrium and kinetic studies, the Langmuir isotherm theory and pseudo-first-order model is appropriate to describe the adsorption process. The adsorption of CR is spontaneous and exothermic according to the thermodynamics parameters (ΔGθ, ΔHθ and ΔSθ). The adsorption force dominated the Van der Waals force, biofloculation and chemisorption. The Fe3O4@bacteria could be applied potentially as an absorbent with high efficiency and environmentally friendly remediation of dyeing wastewater.

Nowadays manipulators are widely used in logistics systems, thus being important to improve the efficiency. In this paper, we transform the task sequencing problem of manipulator into a dynamic traveling salesman problem (DTSP), and use the Monte Carlo tree search (MCTS) approach to determine the execution order of the tasks. MCTS is an effective self-learning algorithm, which consists of four phases, i.e., initialization, simulation, selection and back propagation. Furthermore, to fit the dynamic feature of real-life applications, we introduce a dynamic mechanism using the information of historically found solutions. Finally, we carry out experiments based on 30 randomly generated task sets. The results show that, compared to the most popular method which executes all the tasks in sequence, MCTS is able to save 14.37%, 15.68%, 18.10% execution time (respectively on the small-scale, mid-scale and large-scale task sets), indicating its ability in improving the efficiency of manipulator.

Shape memory alloys (SMAs) are materials that have the ability to return to their predetermined shapes when heated. Using electrically heated SMAs, actuators can be designed for motion and force control. In this paper, the development and testing of a snake robot that uses SMAs as actuators is presented. An eight-segment robot is designed to move similar to the rectilinear motion of a natural snake. A pair of SMA wires are implemented into each segment. One of the SMA wires in each segment is heated at a time, and it acts like a muscle to change the shape of the segment. A sequence of activation for the SMA wires is designed for the robot to move forward and backward. A prototype robot is built, and it can move well with the desired locomotion