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Taking the rotor system supported by angular contact ball bearing as the research object, the dynamic model of rotor bearing system is established by using Lagrange equation. Based on the Archard wear model, the calculation model of wear depth of bearing raceways considering lubrication effects is presented. The wear depth is introduced into the system dynamics model as the bearing clearance. The dynamic characteristics of rotor-bearing system and the evolution of bearing wear are carefully analyzed taking into account the rotor speed, bearing preload and disc position. The results show that the influence of bearing wear on dynamic characteristics of rotor-bearing system is closely related to rotor speed and bearing preload. Changing disc position does not lead to the significant variation of dynamic characteristics of rotor-bearing system with wear depth of bearing raceways. The rotor speed significantly affects the bearing wear, the bearing preload has very limited effect on bearing wear, and the variation of the disc position results in the weak difference of wear depth of bearings.

In order to clarify the effects of different working condition parameters and quantify their influence degree on bearing wear in the spindle system, the bearing wear in the spindle system supported by multi-bearing was carried out. Firstly, the calculation method of wear coefficient considering the lubrication state is introduced, and the wear depth model of the angular contact ball bearing is deduced. Second, the wear depth of the inner and outer raceways of the bearing is calculated based on the motion parameters and contact parameters of the bearing rolling elements obtained from the system model. The influences of spindle speed, bearing angular misalignment caused by mounting error, external loads and bearing surface roughness on bearing wear are discussed. The results show that the spindle speed has a significant impact on bearing wear, and the change of spindle speed leads to a great difference of bearing wear law. Without bearing angular misalignment, the sum of the wear depth of the inner and outer raceways of each bearing in the spindle system is the smallest. The change of external loads has little effect on bearing wear, but the increase in surface roughness can significantly increase the wear depth of the bearing.

Abstract Background Despite plausible biological mechanisms, the differential abilities of phylloquinone (PK) and menaquinones (MKn) to prevent bone loss remain controversial. The objective of the current study was to compare the effects of PK, menaquinone-4 (MK-4) and menaquinone-7 (MK-7) on the rate of bone loss in ovariectomized (OVX) Norway rats. A secondary aim was to compare the effects of vitamin K with those of bisphosphonates (BP) on bone loss. Methods Rats (n = 96) were randomized to 6 dosing groups [n = 16/group; Sham; OVX; OVX + BP (100 μg/kg/100 μg/mL saline sc); OVX + PK; OVX + MK-4; and OVX + MK-7] for 6 wk. Equimolar daily doses of 107 mg PK/kg, 147 mg MK-4/kg, and 201 mg MK-7/kg diet were provided. Results BP significantly increased bone strength and bone mineral density (BMD) vs. OVX (P < 0.05). However, PK, MK-4 or MK-7 did not change bone strength or BMD compared to the OVX group. Whereas supplementation of PK, MK-4 and MK-7 increased serum and tibia concentrations of each respective form, PK concentrations were consistently higher despite equimolar intakes. Conclusion PK, MK-4, and MK-7 do not appear to prevent bone loss in OVX rats when administered concurrent with adequate intake of other nutrients.

Objectives: Engelhardia roxburghiana Wall is a plant of the Juglandaceae family, and its leaves is the main part used as a medicine. It is used to relieve heat and pain, gasification, and dampness. The purpose of this review is to provide a systematic review about the botany, traditional uses, phytochemistry, pharmacology, and toxicology of this plant. Key findings: Many compounds have been isolated and identified from the plant, including flavonoids, triterpenoids, steroids, quinones, essential oils, and other types of chemical constituents. Extensive pharmacological activities of the extracts or compounds of E. roxburghiana Wall in vivo and in vitro were mainly confirmed, including anti-cancer, anti-diabetic, anti-inflammatory, and anti-allergic effects. Summary: In this paper, the botany, traditional uses, phytochemistry, and pharmacology of E. roxburghiana Wall were reviewed. In the future, E. roxburghiana Wall needs further study, such as paying more attention to quality control and the utilization on agriculture. In addition, discussing the medicinal components of decoction as well as the toxicity will also contribute to the progress of clinical trial studies. [ABSTRACT FROM AUTHOR]

Morinda officinalis How oligosaccharide (MOO) stands as one of the principal active constituents of M. officinalis How, widely employed in traditional Chinese medicine. The methods for MOO extraction predominantly encompass hot water extraction, ethanol extraction, ultrasonic-assisted extraction, and microwave-assisted extraction. Distinct extraction techniques yield varying MOO quantities. MOO encompasses a diversity of oligosaccharides, including bajijiasu, sucrose, 1-kestose, nystose, mannose, 1F-fructofuranosylnystose, 1,1,1,1-kestohexose, fructoheptasaccharide, inulin-type hexasaccharide, inulin-type heptasaccharide, inulotriose, inulotetraose, inulopentaose, and mannose. MOO exhibits a wide spectrum of biological activities, exerting specific effects on the nervous system, cardiovascular system, motor system, reproductive system, and immune system. It demonstrates antidepressant properties, offers potential in mitigating Alzheimer's disease, stimulates angiogenesis, and possesses anti-osteoporotic and other pharmacological effects. Clinically, when combined with various antidepressants, MOO exhibits specific therapeutic efficacy across multiple forms of depression. As a naturally occurring plant oligosaccharide, MOO holds diverse pharmaceutical applications. This article conducts a review of the latest extraction and purification methodologies, structural characterization analysis, biological activity assessment, and clinical applications of MOO. Such a comprehensive analysis yields innovative insights for advancing the research and application of MOO in the future. [ABSTRACT FROM AUTHOR]