19 research outputs found
Preparation of a nano emodin transfersome and study on its anti-obesity mechanism in adipose tissue of diet-induced obese rats
OBJECTIVE: To describe the preparation of nano emodin transfersome (NET) and investigate its effect on mRNA expression of adipose triglyceride lipase (ATGL) and G0/G1 switch gene 2 (G0S2) in adipose tissue of diet-induced obese rats. METHODS: NET was prepared by film-ultrasonic dispersion method. The effects of emodin components at different ratios on encapsulation efficiency were investigated.The NET envelopment rate was determined by ultraviolet spectrophotometry. The particle size and Zeta potential of NET were evaluated by Zetasizer analyzer. Sixty male SD rats were assigned to groups randomly. After 8-week treatment, body weight, wet weight of visceral fat and the percentage of body fat (PBF) were measured. Fasting blood glucose and serum lipid levels were determined. The adipose tissue section was HE stained, and the cellular diameter and quantity of adipocytes were evaluated by light microscopy. The mRNA expression of ATGL and G0S2 from the peri-renal fat tissue was assayed by RT-PCR. RESULTS: The appropriate formulation was deoxycholic acid sodium salt vs. phospholipids 1:8, cholesterol vs. phospholipids 1:3, vitamin Evs. phospholipids 1:20, and emodin vs. phospholipid 1:6. Zeta potential was −15.11 mV, and the particle size was 292.2 nm. The mean encapsulation efficiency was (69.35 ± 0.25)%. Compared with the obese model group, body weight, wet weight of visceral fat, PBF and mRNA expression of G0S2 from peri-renal fat tissue were decreased significantly after NET treatment (all P < 0.05), while high-density lipoprotein cholesterol (HDL-C), the diameter of adipocytes and mRNA expression of ATGL from peri-renal fat tissue were increased significantly (all P < 0.05). CONCLUSION: The preparation method is simple and reasonable. NET with negative electricity was small and uniform in particle size, with high encapsulation efficiency and stability. NET could reduce body weight and adipocyte size, and this effect was associated with the up-regulation of ATGL, down-regulation of G0S2 expression in the adipose tissue, and improved insulin sensitivity
Integrated Sizing and Energy Management for Four-Wheel-Independently-Actuated Electric Vehicles Considering Realistic Constructed Driving Cycles
This paper presents an integrated optimization framework of sizing and energy management for four-wheel-independently-actuated electric vehicles. The optimization framework consists of an inner and an outer layer that are responsible for energy management, i.e., torque allocation, and powertrain parameter optimizations. The optimal torque allocation in the inner layer is achieved via the dynamic programming (DP) method while the desirable powertrain parameters in the outer layer are pursued based on the exhaustive method. In order to verify the proposed optimization framework, two driving cycles are constructed to represent the comprehensive and realistic driving conditions. One cycle is built by combining six typical driving cycles, which cover urban, high-way and rural driving styles to enhance representativeness. The other one is synthesized using the Markov chain method based on a vast quantity of real-time operating data of electric vehicles in Beijing. Simulation results demonstrate that the proposed strategy decreases the power consumption by 15.1% and 13.3%, respectively, in the two driving cycles, compared to the non-optimal, even-torque-allocation strategy
Experimental Study on the Effect of Long-Term Water Injection on Micropore Structure of Ultralow Permeability Sandstone Reservoir
During the long-term waterflooding (LTWF) in oil reservoirs, the formation is subject to permeability reduction as clay release and fine migration. At present, the mechanisms of permeability impairment in both macroscopic and microscopic pore structures in ultralow permeability reservoirs under LTWF are unclear. This statement epitomizes the main objective of this work: to understand how long-term waterflood changes porous structures and thus compromises permeability. The standard core flow experiments in conjunction with a couple of tests consisting of online nuclear magnetic resonance (NMR), high-pressure mercury intrusive penetration (HPMIP), X-ray diffraction (XRD), and scanning electron microscope (SEM) were performed to determine the mineral compositions, macrophysical properties, and micropore structures of two kinds of cores with different natures of pore distribution (i.e., unimodal and bimodal) before and after LTWF in Yan Chang field China. Results showed that the permeability decreased while the porosity increased after the LTWF. With respect to the pore size distribution, the small pores (SPs) decreased and the large pores (LPs) increased for both cores. For the unimodal core, the distribution curve shifted upwards with little change in the radius of the connected pores. For the bimodal core, the curve shifted to the right with an increasing radius of connected pores. With respect to the characteristic parameters, the average pore radius, median pore radius, structural coefficient, and tortuosity increased, while the relative sorting coefficient decreased. The relative changes of the parameters for the unimodal core were much smaller than those for the bimodal core. With respect to the clays, chlorite accounted for a majority proportion of the clays, and its content increased after LTWF. According to these changes, the mechanism of LTWF at different stages was interpreted. At the early stages, the blockage of the released clays occurred in SPs. Some of the middle pores (MPs) and LPs became larger due to the release and some of them became smaller due to the accumulation. At the middle stage, the blockage of SPs weakened. Some flow channels formed by MPs and LPs became dominant flow channels gradually. The effluxes of particles occurred, resulting in a significant increase in porosity. At the late stage, the stable flow channels have formed. The higher response of the bimodal core to LTWF could be attributed to its higher content of chlorite, which was more likely to accumulate. This study clarifies the mechanism of fine-migration-induced formation damage in microscopic pore structures and the migration pattern of clay minerals in ultralow permeability reservoirs. The work provides potential guidance for optimizing waterflood strategies in ultralow permeability reservoirs
Differential Responses of Soil Microbial and Carbon‐Nitrogen Processes to Future Environmental Changes Across Soil Depths and Environmental Factors
Abstract Accurately predicting carbon‐climate feedbacks relies on understanding the environmental factors regulating soil organic carbon (SOC) storage and dynamics. Here, we employed a microbial ecological model (MEND), driven by downscaled output data from six Earth system models under two Shared Socio‐economic Pathways (SSP1‐2.6 and SSP5‐8.5) scenarios, to simulate long‐term soil biogeochemical processes. We aim to analyze the responses of soil microbial and carbon‐nitrogen (C‐N) processes to changes in environmental factors, including litter input (L), soil moisture (W) and temperature (T), and soil pH, in a broadleaf forest (BF) and a pine forest (PF). For the entire soil layer in both forests, we found that, compared to the baseline period of 2009–2020, the mean SOC during 2081–2100 increased by 40.9%–90.6% under the L or T change scenarios, versus 5.2%–31.0% under the W change scenario. However, soil moisture emerged as a key regulator of SOC, MBC and inorganic N dynamics in the topsoil of BF and PF. For example, W change led to SOC gain of 5.5%–37.2%, compared to the SOC loss of 15.5%–18.0% under L or T scenario. Additionally, a further reduction in soil pH by 0.2 units in the BF, representing the acid rain effect, significantly resulted in an additional SOC gain by 14.2%–21.3%, compared to the LTW (simultaneous changes in the three factors) scenario. These results indicate that the results derived solely from topsoil may not be extrapolated to the entire soil profile. Overall, this study significantly advances our comprehension of how different environmental factors impact the dynamics of SOC and the implications they have for climate change
Free-walking: Pedestrian inertial navigation based on dual foot-mounted IMU
The inertial navigation system (INS), which is frequently used in emergency rescue operations and other situations, has the benefits of not relying on infrastructure, high positioning frequency, and strong real-time performance. However, the intricate and unpredictable pedestrian motion patterns lead the INS localization error to significantly diverge with time. This paper aims to enhance the accuracy of zero-velocity interval (ZVI) detection and reduce the heading and altitude drift of foot-mounted INS via deep learning and equation constraint of dual feet. Aiming at the observational noise problem of low-cost inertial sensors, we utilize a denoising autoencoder to automatically eliminate the inherent noise. Aiming at the problem that inaccurate detection of the ZVI detection results in obvious displacement error, we propose a sample-level ZVI detection algorithm based on the U-Net neural network, which effectively solves the problem of mislabeling caused by sliding windows. Aiming at the problem that Zero-Velocity Update (ZUPT) cannot suppress heading and altitude error, we propose a bipedal INS method based on the equation constraint and ellipsoid constraint, which uses foot-to-foot distance as a new observation to correct heading and altitude error. We conduct extensive and well-designed experiments to evaluate the performance of the proposed method. The experimental results indicate that the position error of our proposed method did not exceed 0.83% of the total traveled distance
A Bubble-Assisted Approach for Patterning Nanoscale Molecular Aggregates
We demonstrate a new approach to pattern functional organic molecules with a template of foams, and achieve a resolution of sub 100 nm. The bubble-assisted assembly (BAA) process is consisted of two periods, including bubble evolution and molecular assembly, which are dominated by the Laplace pressure and molecular interactions, respectively. Using TPPS (meso-tetra(4-sulfonatophenyl) porphyrin), we systematically investigate the patterns and assembly behaviour in the bubble system with a series of characterizations, which show good uniformity in nanoscale resolution. Theoretical simulations reveal that TPPS's J-aggregates contribute to the ordered construction of molecular patterns. Finally, we propose an empirical rule for molecular patterning approach, that the surfactant and functional molecules should have the same type of charge in a two-component system. This approach exhibits promising feasibility to assemble molecular patterns at nanoscale resolution for micro/nano functional devices
N-fertilization has different effects on the growth, carbon and nitrogen physiology, and wood properties of slow- and fast-growing Populus species
To investigate how N-fertilization affects the growth, carbon and nitrogen (N) physiology, and wood properties of poplars with contrasting growth characteristics, slow-growing (Populus popularis, Pp) and fast-growing (P. alba×P. glandulosa, Pg) poplar saplings were exposed to different N levels. Above-ground biomass, leaf area, photosynthetic rates (A), instantaneous photosynthetic nitrogen use efficiency (PNUE (i)), chlorophyll and foliar sugar concentrations were higher in Pg than in Pp. Foliar nitrate reductase (NR) activities and root glutamate synthase (GOGAT) activities were higher in Pg than in Pp as were the N amount and NUE of new shoots. Lignin contents and calorific values of Pg wood were less than that of Pp wood. N-fertilization reduced root biomass of Pg more than of Pp, but increased leaf biomass, leaf area, A, and PNUE(i) of Pg more than of Pp. Among 13 genes involved in the transport of ammonium or nitrate or in N assimilation, transcripts showed more pronounced changes to N-fertilization in Pg than in Pp. Increases in NR activities and N contents due to N-fertilization were larger in Pg than in Pp. In both species, N-fertilization resulted in lower calorific values as well as shorter and wider vessel elements/fibres. These results suggest that growth, carbon and N physiology, and wood properties are more sensitive to increasing N availability in fast-growing poplars than in slow-growing ones, which is probably due to prioritized resource allocation to the leaves and accelerated N physiological processes in fast-growing poplars under higher N levels