Search

Arsenic and fluoride are two natural components affecting human health. Long-term exposure to arsenic and fluoride, mainly through drinking water intake, can lead to arsenicosis and fluorosis. In this paper, we summarized the distribution and hydrochemical characteristics of high-arsenic and high-fluoride groundwater, and reviewed the arsenicosis and fluorosis distribution due to consumption of high-arsenic and high-fluoride groundwater in China. The results show that there are 20 major provinces//autonomous regions (about 60%) in China suffering from high-arsenic groundwater, and these high-arsenic groundwater provinces are mainly located in the fluvial/alluvial-lacustrine plains and basins located in arid/semi-arid regions and alluvial plains/basins and river deltas in humid/semi-humid regions. Drinking water arsenicosis has been found in 13 provinces/autonomous regions, with Shanxi and Inner Mongolia being the two most seriously affected areas. High-fluoride groundwater is widely distributed in north, northeast and northwest parts of China, occurring mainly in shallow groundwater. Fluorosis has been found in 29 provinces/autonomous regions. With the continuous implementation of water quality improvement projects, drinking water fluorosis and arsenic poisoning have been effectively controlled. However, the long-term maintenance and operation of the water quality improvement project need to be further strengthened.

The prevalence of hydatidosis due to animal husbandry development poses significant health risks to people in the Shiqu County of Sichuan Province, China, where people depend mainly on surface water for domestic uses, which, however, is contaminated due to the development of the animal husbandry. Therefore, groundwater which is protected by the vadose zone and has better quality is now proposed to replace the contaminated surface water as a new source of water supply in this area. To find a high-quality groundwater resource, a detailed investigation and assessment was carried out in this study. The occurrence and distribution of the hydatidosis caused by the consumption of the contaminated surface water were analyzed. The World Health Organization (WHO) and national standards were applied to assess the suitability of groundwater for drinking purpose, and SAR, RSC, %Na, PI were used to evaluate the groundwater quality for irrigation usage. In addition, the overall groundwater quality was assessed using an entropy water quality index (EWQI), and its relationships with the physicochemical indices were discussed using the multiple linear regression models to explore the most important physicochemical indices affecting the groundwater quality. Finally, some measures for the prevention and treatment of the hydatidosis disease were proposed. The results show that the groundwater found beneath the study area is generally in good to excellent quality with low salinity and major ions. Groundwater in all constructed wells except only one is suitable for domestic and irrigation purposes with majority of the samples falling into HCO3-Ca·Mg type. The overall groundwater quality is mainly affected by COD, SO42−, and TH. Measures to reduce the incidence of hydatidosis such as cutting off the hydatidosis exposure pathway and improving the sanitation system are proposed.

Phosphorylation of G-protein-coupled receptors (GPCRs) by GPCR kinases (GRKs) desensitizes G-protein signalling and promotes arrestin signalling, which is also modulated by biased ligands1–6. The molecular assembly of GRKs on GPCRs and the basis of GRK-mediated biased signalling remain largely unknown owing to the weak GPCR–GRK interactions. Here we report the complex structure of neurotensin receptor 1 (NTSR1) bound to GRK2, Gαqand the arrestin-biased ligand SBI-5537. The density map reveals the arrangement of the intact GRK2 with the receptor, with the N-terminal helix of GRK2 docking into the open cytoplasmic pocket formed by the outward movement of the receptor transmembrane helix 6, analogous to the binding of the G protein to the receptor. SBI-553 binds at the interface between GRK2 and NTSR1 to enhance GRK2 binding. The binding mode of SBI-553 is compatible with arrestin binding but clashes with the binding of Gαqprotein, thus providing a mechanism for its arrestin-biased signalling capability. In sum, our structure provides a rational model for understanding the details of GPCR–GRK interactions and GRK2-mediated biased signalling.

In this paper, aiming at the problem of high-precision trajectory tracking of the gantry welding robot system under the influence of uncertain factors, a composite adaptive fuzzy compensation controller based on the computed torque control strategy has been proposed. The controller is composed of an adaptive fuzzy feedback control strategy and a dead zone adaptive fuzzy control strategy, which realizes high-precision trajectory tracking of the gantry welding robot, improves the solving speed of the control algorithm, and its tracking errors has been reduced. Screw theory and Lie group lie algebra are used to solve the problem of high algorithm complexity of controllers in multi-degree-of-freedom robot systems due to Newton-Euler dynamics modeling. Based on the computed torque control, the adaptive fuzzy feedback control strategy is adopted to compensate for the modeling errors and external disturbances in the gantry welding robot system, and the dead zone adaptive fuzzy control strategy is designed to compensate for the nonlinear dead zone structure with unknown parameters. The Lyapunov equation is introduced to prove the stability of the controller. Finally, the controller designed in this paper is compared with the conventional controller through simulation and experiment on the gantry welding robot platform, which verifies the effectiveness and superiority of the controller.

Thyroid-stimulating hormone (TSH), through activation of its G-protein-coupled thyrotropin receptor (TSHR), controls the synthesis of thyroid hormone—an essential metabolic hormone1–3. Aberrant signalling of TSHR by autoantibodies causes Graves’ disease (hyperthyroidism) and hypothyroidism, both of which affect millions of patients worldwide4. Here we report the active structures of TSHR with TSH and the activating autoantibody M225, both bound to the allosteric agonist ML-1096, as well as an inactivated TSHR structure with the inhibitory antibody K1-707. Both TSH and M22 push the extracellular domain (ECD) of TSHR into an upright active conformation. By contrast, K1-70 blocks TSH binding and cannot push the ECD into the upright conformation. Comparisons of the active and inactivated structures of TSHR with those of the luteinizing hormone/choriogonadotropin receptor (LHCGR) reveal a universal activation mechanism of glycoprotein hormone receptors, in which a conserved ten-residue fragment (P10) from the hinge C-terminal loop mediates ECD interactions with the TSHR transmembrane domain8. One notable feature is that there are more than 15 cholesterols surrounding TSHR, supporting its preferential location in lipid rafts9. These structures also highlight a similar ECD-push mechanism for TSH and autoantibody M22 to activate TSHR, therefore providing the molecular basis for Graves’ disease.

Aiming at the problem that the traditional inverse solution optimization method is not comprehensive and does not consider the robot structure and actual working conditions, an inverse solution multi-objective optimization method is proposed. This method comprehensively considers the structural size and working state of the welding robot, establishes the stiffness performance evaluation index, optimizes the performance index of the subsequent connecting rod movement area caused by joint rotation, and selects the optimal inverse solution combined with the principle of “minimum joint displacement.” Compared with the traditional method, this method is more comprehensive. It makes the variation range of the rear three small joints of the welding robot larger than the front three large joints, which reduces the power consumption. In addition, it also improves the stiffness of the welding robot at the trajectory point, which ensures the reliability of the welding robot. On this basis, for linear and arc welds, the position interpolation of cartesian space line and arc trajectory based on the S-shaped acceleration and deceleration curve and the posture interpolation of spherical linear interpolation based on unit quaternion are realized. MATLAB simulation results show that the combination of the inverse optimization method and the interpolation method makes the end trajectory, velocity, acceleration, posture curve, and joint displacement curve of the welding robot continuous, smooth, and without mutation.

The p38 mitogen-activated protein kinases (MAPKs) are associated with insect immunity, tissue repair, and the insecticidal activity of Bacillus thuringiensis(Bt). Here, a p38 MAPK family gene (Sep38β) was identified from Spodoptera exigua. Among the developmental stages, the transcription level of Sep38β was the highest in egg, followed by that in prepupa and pupa. Sep38β expression peaked in Malpighian tubules and the hemolymph of fifth instar larvae. Knockdown of Sep38β or injection of SB203580 (a p38 MAPK inhibitor) significantly downregulated the SeDUOXexpression and reactive oxygen species (ROS) level in the midgut, accounting for deterioration of the midgut to scavenge pathogens and enhancement of Bt insecticidal activity. In conclusion, all the results demonstrate that Sep38β regulates the immune-related ROS level in the insect midgut, which suppresses the insecticidal activity of Bt against S. exiguaby 17–22%. Our study highlights that Sep38β is essential for insect immunity and the insecticidal activity of Bt to S. exiguaand is a potential target for pest control.

Star-shaped and rod-like PbS crystals have been successfully prepared by a novel thioglycolic acid (TGA) assisted hydrothermal method. X-ray diffraction (XRD) reveals that the PbS crystals are of the cubic rock-salt structure and well formed. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) observations show that the morphology of PbS nanocrystals is easily controlled according to sulphur source, lead source, and pH value. Furthermore, the paper gives a preliminary presntation of the mechanism and the critical role of the TGA-assisted hydrothermal synthesis of PbS nanorods

A TGA assisted hydrothermal process was employed to prepare chalcogenide nanorods. The different morphology of CdS nanomaterials prepared with and without the TGA assisted hydrothermal process indicates that TGA plays a critical role in controlling the nucleation and growth of CdS nanomaterials. The paper makes a preliminary presentation of the mechanisms of preparation of chalcogenide nanostructures with and without the use of the TGA assisted hydrothermal synthesis. FeS nanorods and nanoparticles have been prepared by the TGA assisted and without the TGA assisted hydrothermal process, respectively, which confirmed the proposed mechanism. X-ray diffraction (XRD) shows that the nanorods are of orthorhombic structure, and selected area electron diffraction (SAED) pattern showed that the FeS nanorods were single crystalse. Further investigation for the synthesis of other chalcogenides will be undertaken in order to confirm the proposed mechanism.