34 research outputs found
Multi-Scale Research on the Mechanisms of Soil Arching Development and Degradation in Granular Materials with Different Relative Density
Soil arching is significantly influenced by relative density, while its mechanisms have barely been analyzed. A series of DEM numerical simulations of the classical trapdoor test were carried out to investigate the multi-scale mechanisms of arching development and degradation in granular materials with different relative density. For analysis, the granular assembly was divided into three zones according to the particle vertical displacement normalized by the trapdoor displacement δ. The results show that before the maximum arching state (corresponding to the minimum arching ratio), contact forces between particles in a specific zone (where the vertical displacement of particles is larger than 0.1δ but less than 0.9δ) increase rapidly and robust arched force chains with large particle contact forces are generated. The variation in contact forces and force chains becomes more obvious as the sample porosity decreases. As a result, soil arching generated in a denser particle assembly is stronger, and the minimum value of the arching ratio is increased with the sample porosity. After the maximum arching state, the force chains in this zone are degenerated gradually, leading to a decrease in particle contact forces in microscale and an increase in the arching ratio in macroscale. The recovery of the arching ratio after the minimum value is also more significant in simulations with a larger relative density, as the degeneration of contact force chains is more obvious in denser samples. These results indicate the importance of contact force chain stabilities in specific zones for improving soil arching in engineering practice
Maternal exercise represses Nox4 via SIRT1 to prevent vascular oxidative stress and endothelial dysfunction in SHR offspring
Maternal exercise during pregnancy has emerged as a potentially promising approach to protect offspring from cardiovascular disease, including hypertension. Although endothelial dysfunction is involved in the pathophysiology of hypertension, limited studies have characterized how maternal exercise influences endothelial function of hypertensive offspring. In this study, pregnant spontaneously hypertensive rats and Wistar-Kyoto rats were assigned either to a sedentary lifestyle or to swimming training daily, and fetal histone deacetylase-mediated epigenetic modification and offspring vascular function of mesenteric arteries were analyzed. Maternal exercise ameliorated the impairment of acetylcholine-induced vasodilation without affecting sodium nitroprusside-induced vasodilation in mesenteric arteries from the hypertensive offspring. In accordance, maternal exercise reduced NADPH oxidase-4 (Nox4) protein to prevent the loss of nitric oxide generation and increased reactive oxygen species production in mesenteric arteries of hypertensive offspring. We further found that maternal exercise during pregnancy upregulated vascular SIRT1 (sirtuin 1) expression, leading to a low level of H3K9ac (histone H3 lysine 9 acetylation), resulting in the transcriptional downregulation of Nox4 in mesenteric arteries of hypertensive fetuses. These findings show that maternal exercise alleviates oxidative stress and the impairment of endothelium-dependent vasodilatation via SIRT1-regulated deacetylation of Nox4, which might contribute to improved vascular function in hypertensive offspring
Application of human-computer interaction technology in rehabilitation treatment of mental and nervous system diseases
With the development of human-computer interaction technology, how to use intelligent, natural and efficient interaction to promote the development of medicine has gradually become a hot topic of research. Mental and nervous system diseases have a great impact on the quality of people’s daily life. The use of human-computer interaction technology to rehabilitate mental and nervous system diseases can improve the treatment effect and reduce the work intensity of doctors, so it has far-reaching clinical significance. This paper first describes the development process of human-computer interaction technology, and then focuses on the application of human-computer interaction technology such as interactive pen, voice interaction, gait/gesture interaction and physiological computing in the rehabilitation treatment of mental and nervous system diseases, which has important practical significance for improving the use of computer technology to improve traditional medical treatment methods
Application of human-computer interaction technology in rehabilitation treatment of mental and nervous system diseases
With the development of human-computer interaction technology, how to use intelligent, natural and efficient interaction to promote the development of medicine has gradually become a hot topic of research. Mental and nervous system diseases have a great impact on the quality of people’s daily life. The use of human-computer interaction technology to rehabilitate mental and nervous system diseases can improve the treatment effect and reduce the work intensity of doctors, so it has far-reaching clinical significance. This paper first describes the development process of human-computer interaction technology, and then focuses on the application of human-computer interaction technology such as interactive pen, voice interaction, gait/gesture interaction and physiological computing in the rehabilitation treatment of mental and nervous system diseases, which has important practical significance for improving the use of computer technology to improve traditional medical treatment methods
Multi-Scale Research on the Mechanisms of Soil Arching Development and Degradation in Granular Materials with Different Relative Density
Soil arching is significantly influenced by relative density, while its mechanisms have barely been analyzed. A series of DEM numerical simulations of the classical trapdoor test were carried out to investigate the multi-scale mechanisms of arching development and degradation in granular materials with different relative density. For analysis, the granular assembly was divided into three zones according to the particle vertical displacement normalized by the trapdoor displacement δ. The results show that before the maximum arching state (corresponding to the minimum arching ratio), contact forces between particles in a specific zone (where the vertical displacement of particles is larger than 0.1δ but less than 0.9δ) increase rapidly and robust arched force chains with large particle contact forces are generated. The variation in contact forces and force chains becomes more obvious as the sample porosity decreases. As a result, soil arching generated in a denser particle assembly is stronger, and the minimum value of the arching ratio is increased with the sample porosity. After the maximum arching state, the force chains in this zone are degenerated gradually, leading to a decrease in particle contact forces in microscale and an increase in the arching ratio in macroscale. The recovery of the arching ratio after the minimum value is also more significant in simulations with a larger relative density, as the degeneration of contact force chains is more obvious in denser samples. These results indicate the importance of contact force chain stabilities in specific zones for improving soil arching in engineering practice
How Can Prosocial Behavior Be Motivated? The Different Roles of Moral Judgment, Moral Elevation, and Moral Identity Among the Young Chinese
Prior research has shown that moral judgment, moral elevation, and moral identity contribute to prosocial behavior. However, how these three motivating factors interact in predicting prosocial behaviors is not yet clear. The current study proposed and examined a moderated mediation model to illustrate the specific process of how prosocial behavior is motivated by these factors. A total of 264 Chinese undergraduate and graduate students participated in the present study (140 females; age range 17–26, M = 20.25, SD = 1.57). Moral judgment competence, intensity of moral elevation, and moral identity were measured by self-reported scales, and the tendency to engage in prosocial behavior was assessed in a simulated “Ask for help” situation. The multiple regressive results showed that moral elevation mediated the effect of moral judgment on prosocial behavior, and moral identity moderated this mediation through interacting with moral elevation. However, within the proposed model, the mediating effect of moral elevation was stronger in women than in men, while the moderating role of moral identity appeared only in women. These findings imply different methods for men and women to enhance their prosocial behaviors, including the need to pay more attention to developing moral reasoning in men while putting more emphasis on evoking moral emotion and moral traits in women. Together, these results supported the assumptive model and provided a comprehensive framework to explain prosocial behaviors
Characterizing Inter-Sensor Calibration Radiometric Biases between SNPP and NOAA-20 OMPS Nadir Profiler (NP) Sensor Data Records by Using Hybrid Methodologies
The Ozone Mapping & Profiler Suite (OMPS) Nadir Profiler (NP), onboard both the Suomi National Polar-orbiting Partnership (SNPP) satellite and the Joint Polar Satellite System NOAA-20 satellite, is an ultraviolet-visible imaging spectrometer that measures Earth’s albedo by registering terrestrial events to Earth image and extraterrestrial events to Solar spectral images. The NP operates from wavelengths of 250 to 310 nm to profile ozone observations in Earth’s stratosphere. Through years of intensive post-launch calibrations and validations, the Sensor Data Record (SDR) data from both SNPP and NOAA-20 NP sensors demonstrate good performance, meeting the SDR specifications (e.g., Pan et al., 2017). However, it is still challenging to characterize inter-sensor calibration radiometric biases between SNPP and NOAA-20 NP due to non-negligible differences in instrument spectral features, spatial resolution, and temporal resolution. In addition, very narrow NP swath coverage of 250 km not only increases the temporal difference up to 8 days but also extremely reduces the sample size of overlapped observations between the two satellite sensors.
To accurately quantify SNPP and NOAA-20 NP inter-sensor calibration radiometric biases, our study conducts a series of analyses by taking advantage of existing inter-sensor comparison methods, such as the 32-day averaged difference method (Yan et al. 2020), the Simultaneous Nadir Overpass (SNO) method (Cao and Heidinger, 2002), and the deep convective cloud (DCC) method (Wang et al., 2020). Due to limited sample size per geographic location during collocated observations, a 32-day consecutive data set is essential in our zonal mean analysis. Such a data set provides a statistically robust feature for our inter-sensor comparison. The significance is also recognized to ensure the consistency of geographic locations in the data sets between two sensors. The data from two satellites over a similar geographic location need to be simultaneously removed if one satellite observation fails in passing a given quality-control (QC) criterion. Otherwise, resultant mismatches of observations in location can cause large geographic distance differences of over 100 km, further producing many imprecise inter-sensor radiometric bias features. Following those analyses, the impacts of viewing condition discrepancies such as solar zenith angle (SZA) difference on the inter-sensor biases will be assessed using an existing radiative transfer modeling (RTM) to improve the QC criteria in the zonal mean analysis. This is important since the SZA difference can be as large as a couple of degrees between the two NPs’ observations over a similar geographic location. Furthermore, the zonally averaged inter-sensor calibration radiometric bias features will be validated using the RTM and third sensor (e.g., OMPS Nadir Mapper or Visible Infrared Imaging Radiometer Suite) as a transfer, respectively. The validations include some relatively homogenous regions, e.g., the DCC region and open oceans. Finally, we will assess the impacts of SNPP and NOAA-20 NP sensor spectral feature discrepancies in bandpass, radiance sensitivity, wavelength shift, and polarization sensitivity on the inter-sensor biases by using the STAR Vectorized Community Radiative Transfer Model (VCRTM) (Liu and Cao, 2019) and the Algorithm Development Library (ADL) software for OMPS SDR processing