503 research outputs found
Dexmedetomidine relieves inflammatory response in rats with acute spinal cord injury through IKK/NF-κB signaling pathway
Purpose: To examine the effect of dexmedetomidine (DEX) on inflammatory response in spinal cord damage, and involvement of IKK/NF-κB signaling pathway in the process.Methods: Sixty healthy male Wistar rats were selected and randomly divided into sham, control, IKK inhibition, and DEX groups. Rat hind limb motor function in each group at 1, 24 and 48 h after surgery was determined using Basso Beattie Bresnahan (BBB) method, while Western blot assay was used to evaluate the protein expression levels of IL-1β, IKK and NF-κB in spinal cord tissue.Results: In DEX rat group, neuromotor function at 24 and 48 h, and protein expression level of IL-1β in spinal cord tissue significantly decreased, relative to IKK inhibition group (p < 0.05). There were higher protein expressions of IKK and NF-κB in IKK inhibition and DEX groups than in sham rats, but were lower than the corresponding values for model group (p < 0.05). However, these proteins were significantly downregulated in DEX group, relative to the IKK inhibition rats (p < 0.05).Conclusion: DEX mitigates inflammatory response in rats with acute spinal cord injury via IKK/NF-κB signaling pathway. This provides some ideas for research and development of other drugs for the treatment of acute spinal cord injury
Urban greenery and mental wellbeing in adults: Cross-sectional mediation analyses on multiple pathways across different greenery measures
Multiple mechanisms have been proposed to explain how greenery enhances their
mental wellbeing. Mediation studies, however, focus on a limited number of
mechanisms and rely on remotely sensed greenery measures, which do not
accurately capture how neighborhood greenery is perceived on the ground. To
examine: 1) how streetscape and remote sensing-based greenery affect people's
mental wellbeing in Guangzhou, China; 2) whether and, if so, to what extent the
associations are mediated by physical activity, stress, air quality and noise,
and social cohesion; and 3) whether differences in the mediation across the
streetscape greenery and NDVI exposure metrics occurred. Mental wellbeing was
quantified by the WHO-5 wellbeing index. Greenery measures were extracted at
the neighborhood level: 1) streetscape greenery from street view data via a
convolutional neural network, and 2) the NDVI remote sensing images. Single and
multiple mediation analyses with multilevel regressions were conducted.
Streetscape and NDVI greenery were weakly and positively, but not
significantly, correlated. Our regression results revealed that streetscape
greenery and NDVI were, individually and jointly, positively associated with
mental wellbeing. Significant partial mediators for the streetscape greenery
were physical activity, stress, air quality and noise, and social cohesion;
together, they explained 62% of the association. For NDVI, only physical
activity and social cohesion were significant partial mediators, accounting for
22% of the association. Mental health and wellbeing and both streetscape and
satellite-derived greenery seem to be both directly correlated and indirectly
mediated. Our findings signify that both greenery measures capture different
aspects of natural environments and may contribute to people's wellbeing by
means of different mechanisms
Independent grasping scheme of space-servicing-oriented dexterous hand
It is difficult for the robot to grasp objects of any pose by the independent grasping scheme without the help of human. And the independent grasping scheme is also the key technology to develop the AI robot. In order to solve the problem, this paper establishes the full 3D point cloud model of the target object in advance under the PCL point cloud library. The partial view model of the target object in the current working environment is extracted when dexterous hand grasps the target. After aligning the extracted partial view model, the best alignment homogeneous transformation matrix mapping the partial view model to the full 3D point cloud model is obtained. According to the inverse matrix of the obtained matrix, the 3D point cloud model of the target object in the current working environment, where dexterous hand grasps the target, is obtained through the homogeneous transformation. According to the characteristics of the dexterous hand, a grasping algorithm is proposed, which is suitable for the most objects. Finally, the algorithm is verified by the point cloud model of the target object, and finds out the grasping points and grasping pose accurately (the direction of the hand's force). It demonstrates that this algorithm is correct and useful
RESEARCH ON THE INFLUENCE OF VIRTUAL REALITY TECHNOLOGY AND GIS TEACHING REFORM ON GEOGRAPHY STUDENTS’ COGNITIVE IMPAIRMENT
Experimental Investigation on Premixed Combustion in a Diesel Engine with Ultra-Multihole Nozzle
RESEARCH ON THE INFLUENCE OF VIRTUAL REALITY TECHNOLOGY AND GIS TEACHING REFORM ON GEOGRAPHY STUDENTS’ COGNITIVE IMPAIRMENT
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A Simple Graphene NH₃ Gas Sensor via Laser Direct Writing.
Ammonia gas sensors are very essential in many industries and everyday life. However, their complicated fabrication process, severe environmental fabrication requirements and desorption of residual ammonia molecules result in high cost and hinder their market acceptance. Here, laser direct writing is used to fabricate three parallel porous 3D graphene lines on a polyimide (PI) tape to simply construct an ammonia gas sensor. The middle one works as an ammonia sensing element and the other two on both sides work as heaters to improve the desorption performance of the sensing element to ammonia gas molecules. The graphene lines were characterized by scanning electron microscopy and Raman spectroscopy. The response and recovery time of the sensor without heating are 214 s and 222 s with a sensitivity of 0.087% ppm-1 for sensing 75 ppm ammonia gas, respectively. The experimental results prove that under the optimized heating temperature of about 70 °C the heaters successfully help implement complete desorption of residual NH₃ showing a good sensitivity and cyclic stability
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