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Abstract Background The terminal stage of ischemic heart disease develops into heart failure (HF), which is characterized by hypoxia and metabolic disturbances in cardiomyocytes. The hypoxic failing heart triggers hypoxia-inducible factor-1α (HIF-1α) actions in the cells sensitized to hypoxia and induces metabolic adaptation by accumulating HIF-1α. Furthermore, soluble monocarboxylic acid transporter protein 1 (MCT1) and mitochondrial pyruvate carrier 1 (MPC1), as key nodes of metabolic adaptation, affect metabolic homeostasis in the failing rat heart. Aerobic exercise training has been reported to retard the progression of HF due to enhancing HIF-1α levels as well as MCT1 expressions, whereas the effects of exercise on MCT1 and MPC1 in HF (hypoxia) remain elusive. This research aimed to investigate the action of exercise associated with MCT1 and MPC1 on HF under hypoxia. Methods The experimental rat models are composed of four study groups: sham stented (SHAM), HF sedentary (HF), HF short-term exercise trained (HF-E1), HF long-term exercise trained (HF-E2). HF was initiated via left anterior descending coronary artery ligation, the effects of exercise on the progression of HF were analyzed by ventricular ultrasound (ejection fraction, fractional shortening) and histological staining. The regulatory effects of HIF-1α on cell growth, MCT1 and MPC1 protein expression in hypoxic H9c2 cells were evaluated by HIF-1α activatort/inhibitor treatment and plasmid transfection. Results Our results indicate the presence of severe pathological remodelling (as evidenced by deep myocardial fibrosis, increased infarct size and abnormal hypertrophy of the myocardium, etc.) and reduced cardiac function in the failing hearts of rats in the HF group compared to the SHAM group. Treadmill exercise training ameliorated myocardial infarction (MI)-induced cardiac pathological remodelling and enhanced cardiac function in HF exercise group rats, and significantly increased the expression of HIF-1α (p

Geothermal energy is a clean, abundant, and dependable energy source. Because the formation of a geothermal field is often closely linked to the distribution and development of granite, it is crucial to understand the regularity and formation mechanism of granite geothermal resources to advance the field of geothermal energy. Lancang County is located on the southern edge of the Lincang granite, and contains many hot springs. In this paper, we synthesize rock geochemistry, zircon U–Pb chronology, and other methods to interpret the genesis of granites in Lancang County and their geothermal formation patterns. The study area mainly comprises a Middle Triassic S-type granite with high contents of heat-producing elements. Zircon U–Pb dating results show that the intrusion time of the Lancang granite was 239 Ma. The granite is rich in light rare earth elements, depleted in heavy rare earth elements, and characterized by a negative Eu anomaly. The ɛHf values range from −20.3 to 13.6, indicating the presence of mantle material in the source area. Igneous rocks in Lancang County likely formed in the background of an active continental margin associated with the subduction of the Tethys Ocean to the east, which formed an intra-land orogeny. High contents of radioactive thermogenic elements in the granite, fracture development, and additional heat sources from metamorphic rocks combined to generate high-temperature geothermal resources in the study area. The hydrothermal geothermal model of the granite has the following characteristics: a near heat source, large drop, water storage in fractures, simultaneous geothermal influence in deep and shallow layers, and hot spring and geothermal distribution along deep and large faults, etc. The geothermal reservoirs in the study area are classified into four types: internal fissures in granite, granite paleo-weathering crust, tectonic nappe fractures, and sedimentary deposits associated with granite cooling collapse. These types are of great significance to the understanding of the formation of hydrothermal geothermal heat in this granite area.

Asymmetric rolling is beneficial for grain refinement and properties improvement through mass production of metals. This study introduces a novel asymmetric rolling technology, known as dynamic offsets and shear force adjustment (DS) rolling. DS rolling not only achieves roll offset and differential speed/diameter, but maintains a constant offset angle in multiple passes. And rolling mechanics model, finite element model, and rolling experiment is established. The results indicate the advantages of DS rolling in reducing the vertical rolling force with increasing offset angles. Moreover, it is observed that the vertical rolling force initially decreases and subsequently increases as the roll-to-diameter ratio increases. DS rolling enhances both average strain and core strain compared to symmetrical rolling, consequently promoting uniformity in strain distribution and permeability into the core region. The shear stress is the primary factor contributing to the increase in equivalent strain during DS rolling. The adjustment of roller diameter ratio and offset angle allows for control over the shear stress level. DS rolling enhances mechanical properties and refines the grain structure. Notably, at an offset angle of 9°, DS rolling results in a substantial increase in microhardness on the upper surface, center, and lower surface of Cu by 3.31 %, 8.40 %, and 8.19 %, respectively, when compared to symmetrical rolling. Furthermore, DS rolling exhibits an enhanced tensile strength and elongation, yielding improvements of 5.12 % and 38.9 % compared to symmetrical rolling, respectively. Additionally, DS rolling leads to a reduction in grain size by 5.77 %, 17.3 %, and 21.7 % on the upper surface, center, and lower surface, respectively.

China is tectonically composed of a series of plates and orogenic belts and has been influenced by the Pacific and Indian plates since the Late Paleozoic, forming a regular distribution of Mesozoic and Cenozoic granites. As an important source of geothermal energy, granite is the five elements of geothermal enrichment:geothermal sources; geothermal reservoirs; heat transmission; heat caprock; and heat preservation and it is possible to classify the types of geothermal resources in China according to their distribution in combination with neotectonic movements. China's geothermal energy can be divided into hydrothermal and hot dry rock types in basins and orogenic belts, respectively. Geothermal resources can be divided into hydrothermal, rock, magma, and hybrid geothermal types according to the heat carrier type. Basin geothermal resources are dominated by hydrothermal types, while geothermal energy in orogenic belts with granite includes both hydrothermal and hot dry rock types. Geothermal resources in China can be divided into 6 distinct geothermal regions and 13 subregions, of which the Southwest and Southeast China regions and the Qaidam-Qilian and Jiaoliao subregions in North China with Mesozoic and Cenozoic granites are the most favorable areas for high-temperature hydrothermal and hot dry rock sources. China has complex geological conditions, diverse types of geothermal resources, and broad prospects for development and utilization. Having performed extensive shallow hydrothermal geothermal development and utilization and completed various power generation tests, China's geothermal development and utilization is in a critical stage of transition from the direct utilization of shallow hydrothermal resources to high-temperature geothermal or hot dry rock power generation in middle and deep layers. Basic theoretical research, key technology breakthroughs, and policy incentives are the main issues that need to be addressed in the geothermal industry.

As an important component of the exploration and evaluation of geothermal resources, the formation model has unique formation and distribution rule in different regions. Reliable geological models need to be established to help in temperature prediction, favorable area selection, and drilling design studies prior to the development of geothermal resources. This paper provides an integrated approach for analyzing the formation models of geothermal resources by combining geological studies and the wide-field electromagnetic method. The resistivity profile is converted into a geologic profile by analyzing the fault distribution, stratigraphic lithology, magmatic rock development, and signal changes of the profile. Comprehensively analyzing the geological elements including the heat sources, water sources, thermal reservoirs, transport conditions, cap rock, and preservation conditions, we investigate the matching relationship of the geological elements on the geologic profile and establish a formation model of the geothermal resources. This approach avoids the respective limitations of geological and geophysical methods, and the formation model established by this approach is comprehensive, intuitive, and accurate and can provide support for the development of geothermal resources.

Estimating leaf chlorophyll content (LCC) in a timely manner and accurately is of great significance for the precision management of rape. The spectral index derived from UAV images has been adopted as a non-destructive and efficient way to map LCC. However, soil background impairs the performance of UAV-based LCC estimation, limiting the accuracy and applicability of the LCC estimation model, and this issue remains to be addressed. Thus, this research was conducted to study the influence of soil pixels in UAV RGB images on LCC estimation. UAV campaigns were conducted from overwintering to flowering stages to cover the process of soil background being gradually covered by rapeseed plants. Three planting densities of 11.25, 18.75, and 26.26 g/m2 were chosen to further enrich the different soil background percentage levels, namely, the rape fractional vegetation coverage (FVC) levels. The results showed that, compared to the insignificant difference observed for the ground measured LCC at a certain growth stage, a significant difference was found for most of the spectral indices extracted without soil background removal, indicating the influence of soil background. Removing soil background during the extraction of the spectral index enhanced the LCC estimation accuracy, with the coefficient of determination (R2) increasing from 0.58 to 0.68 and the root mean square error (RMSE) decreasing from 5.19 to 4.49. At the same time, the applicability of the LCC estimation model for different plant densities (FVC levels) was also enhanced. The lower the planting density, the greater the enhancement. R2 increased from 0.53 to 0.70, and the RMSE decreased from 5.30 to 4.81 under a low planting density of 11.25 g/m2. These findings indicate that soil background removal significantly enhances the performance of UAV-based rape LCC estimation, particularly under various FVC conditions.

This work establishes an analytical model for determining the critical velocity for proppant flowback, and evaluates how proppant flowback affects fracture conductivity for tight reservoirs. The multiphase effects are considered for determining the critical velocity for proppant flowback before and after fracture closure, respectively. The model’s performance is demonstrated by comparing the results against previous models. A finite-element model is built to simulate the proppant flowback process for a hydraulic-fractured well completed in the Ordos Basin. The change in fracture conductivity caused by proppant flowback for several scenarios with varying saturation and net pressure in fractures is further quantitatively assessed. Our results highlight the importance of multiphase effects in determining the critical velocity for proppant flowback at relatively low water saturation in fractures. The critical velocity generally increases with increasing water saturation in fractures and net pressure in fractures. At a flowback velocity higher than the critical value, the loss in fracture conductivity becomes relatively more pronounced at a lower water saturation in fractures and a lower net pressure in fractures. The findings of this work are expected to provide insights into the mechanisms of proppant flowback and flowback drawdown management for field operations in tight reservoirs.

Abstract Alzheimer’s disease (AD) is a major subtype of neurodegenerative dementia caused by long-term interactions and accumulation of multiple adverse factors, accompanied by dysregulation of numerous intracellular signaling and molecular pathways in the brain. At the cellular and molecular levels, the neuronal cellular milieu of the AD brain exhibits metabolic abnormalities, compromised bioenergetics, impaired lipid metabolism, and reduced overall metabolic capacity, which lead to abnormal neural network activity and impaired neuroplasticity, thus accelerating the formation of extracellular senile plaques and intracellular neurofibrillary tangles. The current absence of effective pharmacological therapies for AD points to the urgent need to investigate the benefits of non-pharmacological approaches such as physical exercise. Despite the evidence that regular physical activity can improve metabolic dysfunction in the AD state, inhibit different pathophysiological molecular pathways associated with AD, influence the pathological process of AD, and exert a protective effect, there is no clear consensus on the specific biological and molecular mechanisms underlying the advantages of physical exercise. Here, we review how physical exercise improves crucial molecular pathways and biological processes associated with metabolic disorders in AD, including glucose metabolism, lipid metabolism, Aβ metabolism and transport, iron metabolism and tau pathology. How metabolic states influence brain health is also presented. A better knowledge on the neurophysiological mechanisms by which exercise improves AD metabolism can contribute to the development of novel drugs and improvement of non-pharmacological interventions.

Although significant progress has been made in the geological theory and exploration and development of shale gas in China, the research on the geological particularity and enrichment regularity associated with shale gas accumulation remains weak. With this in mind, we analyzed the shale gas accumulation patterns in China. The findings show that: (1) A variety of organic-rich shales were deposited in the continental margin-type marine and transitional environments during the Pre-Mesozoic period and the basin-type terrestrial environment during the Mesozoic and Cenozoic eras. (2) The basins dominated by Mesozoic and Cenozoic terrestrial sediments superimpose on the Pre-Mesozoic continental margin-type marine–or transitional-facies sediments. The former developed the terrestrial shales with large thickness, high organic matter abundance, new age, and low thermal maturity; meanwhile, the deep parts of the basins are favorable for shale gas enrichment. However, the latter preserves the shale with old age, high thermal maturity, and undergoing multiphase tectonic movements; and the tectonically stable regions are favorable for shale gas enrichment. (3) The aulacogens mainly formed in the Meso-Neoproterozoic, Sinian-Ordovician, and Devon-Triassic periods are favorable for marine organic-rich shale deposition; moreover, this type of shale and other types including transitional facies shales with favorable reservoir-forming assemblages, coal-measure shales in small and medium-sized basins, and low-medium mature shales affected by magma intrusion, have jointly constituted the various shale gas accumulation patterns in China. (4) Based on the drilling discoveries in China, shale gas accumulation patterns can be categorized into two types: tectonic-controlled and stratigraphic-controlled. The former is mainly related to structural features, whereas the latter is mainly related to the variation of lithology and strata. (5) Shale development and gas content are mainly affected and controlled by geological factors including sedimentation, diagenesis, and later tectonic movements. Favorable sedimentary environments, appropriate thermal maturity, good sealing capacity of caprock, and excellent structural preservation are the necessary conditions for shale gas enrichment.

Abstract Background Moderate physical exercise is conducive to the brains of healthy humans and AD patients. Previous reports have suggested that treadmill exercise plays an anti-AD role and improves cognitive ability by promoting amyloid clearance, inhibiting neuronal apoptosis, reducing oxidative stress level, alleviating brain inflammation, and promoting autophagy–lysosome pathway in AD mice. However, few studies have explored the relationships between the ubiquitin–proteasome system and proper exercise in AD. The current study was intended to investigate the mechanism by which the exercise-regulated E3 ubiquitin ligase improves AD. Methods Both wild type and APP/PS1 transgenic mice were divided into sedentary (WTC and ADC) and exercise (WTE and ADE) groups (n = 12 for each group). WTE and ADE mice were subjected to treadmill exercise of 12 weeks in order to assess the effect of treadmill running on learning and memory ability, Aβ plaque burden, hyperphosphorylated Tau protein and E3 ubiquitin ligase. Results The results indicated that exercise restored learning and memory ability, reduced Aβ plaque areas, inhibited the hyperphosphorylation of Tau protein activated PI3K/Akt/Hsp70 signaling pathway, and improved the function of the ubiquitin–proteasome system (increased UCHL-1 and CHIP levels, decreased BACE1 levels) in APP/PS1 transgenic mice. Conclusions These findings suggest that exercise may promote the E3 ubiquitin ligase to clear β-amyloid and hyperphosphorylated Tau by activating the PI3K/Akt signaling pathway in the hippocampus of AD mice, which is efficient in ameliorating pathological phenotypes and improving learning and memory ability.

Abstract Red tide data are typical multivariate time series (MTS) and complete data help analyze red tide more conveniently. However, missing values due to artificial or accidental events hinder further analysis of red tide phenomenon. Generative adversarial network (GAN) is effective in capturing distribution of MTS while the imputation performance is far from satisfactory, especially in conditions of high missing rate. One of the remaining open challenges is that common GAN-based imputation methods usually lack the ability to excavate implicit correlations between different attributions and downstream tasks, from which advanced latent information about missing values can be mined to improve imputation performance. To deal with the problem, a novel multi-task learning-based generative adversarial imputation network (MTGAIN) is proposed by introducing the prediction task into GAN to unearth more detailed information about missing values to better model distribution of red tide MTS. Furthermore, the homoscedastic uncertainty of multiple tasks is exploited to balance the weights of losses between generation and prediction tasks. The experiments conducted on a real-world dataset demonstrate that MTGAIN outperforms existing methods in terms of imputation and post-imputation performances, especially in conditions of high missing rate.

A natural amino acid-doped polyaniline nanostructure was prepared by a simple in situ chemical polymerization method in an aqueous medium. The structure and morphology of composite material were characterized by FESEM, TEM, FT-IR, and XRD. The results showed that the product possesses a large aspect ratio and a hollow tubular morphology. As-synthesized products were further applied to remove dyes and heavy metal ions from the aqueous solution, which exhibited good removal capacity toward Congo red (955.6 mg·g−1) and Cr(VI) (60.0 mg·g−1). The adsorption data for the former were found to be well described by the pseudo-first-order kinetic and Langmuir adsorption isotherm model. Thermodynamic studies show that the adsorption of Congo red by GluP is a spontaneous and endothermic process. Moreover, cyclic experiment results show that the polyaniline composites exhibited good recyclability. Therefore, these amino acid-doped polyaniline nanotubes can be expected to be an ideal candidate for the removal of organic dye and heavy metal ions from wastewater.

The special engineering characteristics of loess will inevitably bring hidden trouble to the construction of shallow buried subway tunnel. The purpose of this paper is to investigate the variation law of surrounding rock stress, lining stress, and surface settlement in loess tunnel construction and further explore the optimum construction method in the soft loess area. A model test considering the different excavation methods and prereinforcement measures was conducted to measure the surrounding rock pressure, lining stress, and surface settlement under different working conditions. The results show that the sequence of tunnel excavation had a great influence on the stability of the tunnel. As the experimental steps increased, the surrounding rock stress and lining stress at each monitoring section gradually increase. Especially, stress concentration could easily occur at the arch foot of the tunnel. The pre-reinforcement measure, especially the WSS grouting, was more crucial than the excavation method. Considering the number of elements, the combination of DSDM excavation method and WSS grouting reinforcement method was proposed as the final construction method of the tunnel in soft loess area in this paper. The research results can effectively guide the design and construction of a shallow tunnel in the soft loess area.

Pile composite foundation can make good use of the bearing capacity of the soil and pile, which is widely used in the Chinese northwest loess area. However, the theory of pile composite foundation is far from sufficient, hindering its long-term development. Aiming at this problem, a laboratory model test of pile composite foundation in the loess area was conducted to explore the common working mechanism and variations of each bearing stage. Besides, the settlement of the single pile composite foundation was calculated by using the modified tangent modulus method, and the result was compared with the experimental data. The main results of this paper are as follows: Both in the single pile and single pile composite foundation, loading-settlement curves showed a trend of “elastic to elastoplastic to plastic,” accompanied by the appearance of plummeting point. Influenced by the pile group effect, the loading-settlement curve of the group pile composite foundation showed a slow-varying trend without an obvious breakdown point. Pile axis stress increased with the growth of upper load. At the beginning of loading, the pile axis stress indicated such a distribution that stress on both ends of the pile was larger than that in the middle of the pile. When reaching a certain load, the location of the biggest pile axis stress transferred to the pile top, and the pile axis stress decreased gradually as the pile became deep. The side friction resistance in the static load test of the single pile was always positive, whereas in the composite foundation of a single pile and a group of piles, negative side resistance appeared in the upper side of the neutral point. Pile-soil stress ratio in the depth of 12 cm changed with the upper load. The outcome calculated by the modified tangent modulus method had a relatively better consistency with experimental data if the upper load was not too large.

In order to have a better understanding of the real contact area of granular materials, the white light interference method is applied to explore the real surface morphology of clay soils under high stress. Analysis of the surface profile indicates that there exists a support point height z0 with the highest distribution frequency. A concept of a real contact region (from z0 to z0 + d90; d90 represents the particle size corresponding to 90% of the volume fraction) is proposed by combining a surface profile with the particle size distribution of clay soil. It was found that under the compressive stress of 106 MPa–529 MPa, the actual contact area ratio of clay soil varies between 0.375 and 0.431. This demonstrates an increasing trend with the rise of stress. On the contrary, the apparent porosity decreases with an increasing stress, varying between 0.554 and 0.525. In addition, as the compressive stress increases, the cumulative frequency of apparent profile height (from z0 − d90 to z0 + d90) has a concentrated tendency with a limited value of 0.9.

Foundations for offshore wind turbines (OWTs) are mainly open-ended piles that are subjected to cyclic loadings caused by winds, waves and currents. This study aims to investigate the dynamic responses of open-ended pipe pile under lateral cyclic loadings, as well as the characteristics of the soil plug and surrounding soil. Both large-scale indoor model test and discrete element simulation were adopted in this study. The test results show that the resistance of each part of the pipe pile increases linearly with depth during the process of pile driving. The pile side resistance degradation effect was also observed along with the friction fatigue. The soil plug formation rate decreases gradually with an increase in the pile depth. The influence range in the surrounding soil is about 5~6 times of the pile diameter. The cumulative displacement of the pile head increases with the number of cycles. Lateral tangential stiffness and lateral ultimate bearing capacity decreases with an increase in number of cycles. The severe disturbance range of soil around the pile is 2~3 times of the pile diameter. The center of rotation of the pile body is about 0.8 times of the pile body depth. The side frictional resistance and lateral pressure of the pile body is found to fluctuate along the pile body. Additionally, the lateral pressure and side friction resistance decreases gradually with decreasing tendency of the former more than the latter.