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• The activation of osteoclast in OVX rats could activate sensory nerves to release CGRP. • CGRP promoted serotonin release in the brainstem and spinal cord. • Increased brain-derived serotonin inhibited CGRP release in the femur. • CGRP and serotonin were related to osteoporosis and osteoporotic pain. Postmenopausal osteoporosis (PMO) and osteoporotic fracture seriously impair human health in developed countries. The present study aims to explore whether sensory nerves, calcitonin gene-related peptide (CGRP), and brain-derived serotonin are related to bone loss in ovariectomized (OVX) rats. Female rats were grouped into the ovariectomized (OVX) and sham surgery (SHAM) groups. Immunocytochemistry, western blotting, and qPCR were performed to detect CGRP expression in the femurs. The expression levels of serotonin and CGRP in the spinal cord and brainstem were estimated using western blotting, immunofluorescence, and qPCR. ELISA was used to evaluate the serum biomarkers of bone formation and resorption. Bone mineral density was measured using dual-energy X-ray (DXA) analysis. Femur microstructure was imaged by Micro CT. P values less than 0.05 were considered statistically significant. ELISA showed that serum bone alkaline phosphatase (BALP), tartrate-resistant acid phosphatase (TRAP), β-crosslaps, and β-ctx were increased in the OVX group. In the OVX group, in vivo bone mineral density, trabecular bone mineral density, bone volume fraction (BV/TV), and trabecular number (Tb. N) were significantly decreased, while trabecular spacing (Tb. Sp) and trabecular bone pattern factor (Tb. Pf) were markedly increased. In the OVX group, the expression levels of CGRP of the femur were significantly downregulated. In contrast, CGRP and serotonin expression was increased in the spinal cord of the OVX group. Serotonin expression was increased in the brainstem, brainstem nucleus raphe magnus (RMG), and nucleus raphe dorsalis (DRN). Our results indicated that the activation of osteoclast triggered the release of CGRP from nociceptive sensory nerve fibers and transmitted this painful stimulus to the dorsal horn of the spinal cord to release increased CGRP. The descending serotonergic inhibitory system was activated by increased CGRP levels of the spinal cord and promoted serotonin release in the brainstem RMG, DRN, and the spinal cord, contributing to the decreased CGRP level in bone tissue, which revealed a novel mechanism of bone loss in PMO. [ABSTRACT FROM AUTHOR]

• The ground states and the dynamics of the biased bosonic ladder are discussed. • The Meissner, Vortex and two new Plane Wave phases are predicted analytically. • Interestingly, the Plane Wave phases break both Z 2 and time-reversal symmetry. • Rich chiral Bolch oscillations are predicted to distinguish the novel phases. • The work gives an interesting way to explore phases in condensed physics dynamically. The ground states and the dynamics of a biased two-leg flux ladder in the presence of a gravitational field are discussed. In the absence of the gravitational field, the ground states and the critical condition of phase transition are obtained analytically. We identify the Meissner phase, Vortex phase, and interestingly, two new Plane Wave phases, that break both Z 2 and time-reversal symmetry, characterized by the imbalance particle density distribution, asymmetry double well energy band structure in Plane Wave I (PWI) phase and asymmetry single well energy band structure in Plane Wave II (PWII) phase, respectively. In the presence of a longitudinal dc gravitational field, rich chiral Bloch oscillation and Landau-Zener tunneling are predicted theoretically and confirmed numerically. The characteristics of the chiral Bloch oscillation can distinguish the novel phases intuitively. Our work gives an interesting way to discuss the quantum phase transitions in a dynamical way. [ABSTRACT FROM AUTHOR]

To efficiently utilize energy, refrigeration industries, including air conditioning, have put forward higher and higher requirements for the performances of copper pipes used for heat exchangers. Horizontal continuous casting of pipe blank is a key process in production of copper pipes, and optimization of its technological parameters has positive effects on improving the structure uniformity of casting blank. The stability of the performances of pipe blank also directly influences the quality of subsequent machining process. In this paper, numerical analysis was carried out for the temperature field and structure field during solidification of pipe blank in the crystallizer for horizontal continuous casting, and the steady-state sump depth and morphology in the crystallizer for continuous casting, which could be used to evaluate production safety, were obtained. Quantitative analysis was conducted for the laws of influence of different casting technological parameters, such as cooling water flow rate, withdrawal speed, and casting temperature, on the sump morphology in the crystallizer for casting blank and the final distribution of structure field in casting blank. Metallographic experiment was carried out for casting blank, and the results were compared visually with the structure field from simulation calculation, to provide measurable reference bases for further optimizing the horizontal casting technological parameters for copper pipes. [ABSTRACT FROM AUTHOR]

Copper tubes are efficient heat exchange parts in refrigeration industry, and their quality has a bearing on the grade of corresponding products. The cooling process of copper tube after three-roll planetary rolling is a key step in the production of copper tube by the casting and rolling method, and its cooling effect matters to the quality of copper tube products. Aiming at the characteristics of motion of a rolled piece in the through water cooling with a cooling water jacket, the method of "stepwise" moving cooling water jacket was used in this paper to achieve equivalence to the motion of the rolled piece, realizing finite element simulation of the whole process of three-roll planetary rolling and cooling of copper tube. The velocity field and pressure field of the fluid in the cooling water model were analyzed, and it was found that there existed a flow "dead zone" with the velocity below 8 m/s, there was a "negative pressure" phenomenon, and there were more eddy currents occurring. Through the study on the temperature field during the cooling process of the rolled piece, it was found that there was a phenomenon of non-uniform temperature distribution in the cooling process of the rolled piece. With the maximum temperature difference at each monitoring point in the cooling process of rolled piece as the evaluation criterion for the uniformity of temperature distribution in the cooling process of rolled piece, the process parameters affecting the rolled piece cooling effect, including the size of water inlet, the size of water outlet, and the pressure of entering water, were studied respectively, and the optimum process parameter values for improving the quality of rolled pieces were finally obtained. The accuracy of the model was verified by comparatively analyzing the metallographic microstructure and microhardness between the factory produced sample and the thermally simulated sample. • Realize the whole process of three-roll planetary rolling and cooling of the tube. • Simulation method of "stepwise" moving cooling water jacket was used. • It was found that there existed a flow "dead zone". • There were "negative pressure" phenomenon and eddy current phenomena occurring. [ABSTRACT FROM AUTHOR]