Alzheimer’s disease (AD) is an age-related neurodegenerative disorder, characterized by the accumulation of proteinaceous aggregates and neurofibrillary lesions composed of β-amyloid (Aβ) peptide and hyperphosphorylated microtubule-associated protein tau, respectively. It has long been known that dysregulation of cholinergic and monoaminergic (i.e., dopaminergic, serotoninergic, and noradrenergic) systems is involved in the pathogenesis of AD. Abnormalities in neuronal activity, neurotransmitter signaling input, and receptor function exaggerate Aβ deposition and tau hyperphosphorylation. Maintenance of normal neurotransmission is essential to halt AD progression. Most neurotransmitters and neurotransmitter-related drugs modulate the pathology of AD and improve cognitive function through G protein-coupled receptors (GPCRs). Exercise therapies provide an important alternative or adjunctive intervention for AD. Cumulative evidence indicates that exercise can prevent multiple pathological features found in AD and improve cognitive function through delaying the degeneration of cholinergic and monoaminergic neurons; increasing levels of acetylcholine, norepinephrine, serotonin, and dopamine; and modulating the activity of certain neurotransmitter-related GPCRs. Emerging insights into the mechanistic links among exercise, the neurotransmitter system, and AD highlight the potential of this intervention as a therapeutic approach for AD.
Understanding sentiment changes in tourist flow is critical in designing exciting experiences for tourists and promoting sustainable tourism development. This paper proposes a novel analytical framework to investigate the tourist sentiment changes between different attractions based on geotagged social media data. Our framework mainly focuses on visualizing the detailed sentiment changes of tourists and exploring the valuable spatiotemporal pattern of the sentiment changes in tourist flow. The tourists were first identified from social media users. Then, we accurately evaluated the tourist sentiment by constructing a Chinese sentiment dictionary, grammatical rule, and sentiment score. Based on the location information of social media data, we built and visualized the tourist flow network. Last, to further reveal the impact of attractions on the sentiment of tourist flow, the positive and negative sentiment profiles were generated by mining social media texts. We took Beijing, a famous tourist destination in China, as a case study. Our results revealed the following: (1) the temporal trend of tourist sentiment has seasonal characteristics and is significantly influenced by government control policies against COVID-19; (2) due to the impact of the attraction’s historical background, some tourist flows with highly decreased sentiment strength are linked to attractions; (3) on the long journey to the attraction, the sentiment strength of tourists decreases; and (4) bad traffic conditions can significantly decrease tourist sentiment. This study highlights the methodological implications of visualizing sentiment changes during collective tourist movement and provides comprehensive insight into the spatiotemporal pattern of tourist sentiment.
Bone formation in type 2 diabetes mellitus (T2DM) is inhibited by decreased bone formation capacity. Exercise can significantly improve bone metabolism; however, the effect and mechanism of exercise on bone formation in T2DM is not known. In this study, we used the method of a high-fat diet and injecting STZ to build a T2DM mouse model, and the mice were treated with swimming and downhill running for 8 weeks. Their body weights were obtained using an electronic scale. Their bone length and wet weights were measured by Vernier callipers and an electronic balance. The bone microstructure of the distal femur was analysed by Alizarin red staining of paraffin sections and micro-CT. An ALP dye was used to detect the changes in ALP activity in the mouse skull and osteoblasts. Alizarin red staining was applied to stain the osteoblasts produced by BMSCs. The mRNA expression of related factors were detected by RT-PCR. Our results showed that the body weights of T2DM mice were significantly increased by exercise. When the Wnt3a/β-catenin pathway in the bones of T2DM mice is inhibited, their bone formation ability is significantly reduced, resulting in the degradation of the bone tissue morphology and structure. Except for the significant increase in body weight and Runx2 mRNA expression, swimming had no significant effect on bone formation-related indicators in T2DM mice. However, downhill running could significantly increase their body weight, while the tibia length, wet weight, and the trabecular morphological structure of the distal femur and the indexes of bone histomorphology were significantly improved by activating the Wnt3a/β-catenin pathway. Compared with swimming, downhill running can activate the Wnt pathway to improve bone formation ability, thereby improving bone histomorphology. These findings suggest that exercise promotes OB differentiation, osteogenic capacity and enhances bone formation metabolism by regulating Wnt3a/β-catenin signalling in T2DM mice.
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