Abstract
Coronal upflows at the edges of active regions (ARs), which are a possible source of slow solar wind, have been found to connect with dynamics in the transition region. To infer at what ...scale transition region dynamics connect to AR upflows, we investigate the statistical properties of the small-scale dynamics in the transition region underneath the upflows at the edge of NOAA Active Region 11934. With observations from the Interface Region Imaging Spectrograph (IRIS), we found that the Si
iv
1403 Å Doppler map consists of numerous blueshifted and redshifted patches mostly with sizes less than 1 Mm
2
. The blueshifted structures in the transition region tend to be brighter than the redshifted ones, but their nonthermal velocities have no significant difference. With the SWAMIS feature-tracking procedure, we found in IRIS slit-jaw 1400 Å images that dynamic bright dots with an average size of about 0.3 Mm
2
and lifetimes of mostly less than 200 s were spread all over the region. Most of the bright dots appear to be localized, without a clear signature of plasma propagation to a long distance on the projection plane. Surge-like motions with speeds of about 15 km s
−1
could be seen in some events at the boundaries of the upflow region, where the magnetic field appeared to be inclined. We conclude that the transition region dynamics connecting to coronal upflows should occur in at a very fine scale, suggesting that the corresponding coronal upflows should also be highly structured. It is also plausible that the transition region dynamics might just act as stimulation at the coronal base, which then drives the upflows in the corona.
New nano-sized TiO₂ electrorheological (ER) materials doped with different metal (M = Na, Zr, Ce, Al, Ca, Zn) oxides have been prepared. Relationships between the composition, microstructure, ...conductivity, dielectric property and ER effect of these materials have been studied. The results show that doping Na₂O, ZrO₂, Al₂O₃ or CeO₂ can enhance the ER performance of the TiO₂ material, whereas, doping CaO or ZnO would decrease the ER activity of the material. The shear stress (τE) of the suspension (25 wt%) of Na-doped TiO₂ in dimethyl silicone oil reaches 1.6 kPa at the electric field strength E = 4.2 kV/mm and shear rate γ = 300 s⁻¹, and its τᵣ value of 54.6 (τᵣ = τE/τ₀, where τ₀ is the shear stress at no electric field) is seven times higher than that of pure TiO₂ suspension. This high τᵣ value is very advantageous to the use. The dielectric loss tangent (tanδ) plays a dominant role in influencing the ER performance of a particle material, and the effect of the surface area (pore volume, especially) and grain size should be taken into account.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Video person re-identification is a crucial component of a robust surveillance system. Within a video clip, different human regions exhibit unique stability characteristics, which would be harmful to ...generating a discriminative representation. Unfortunately, prior works cannot effectively deal with the stability characteristics of different regions. To tackle this problem, we propose a Multiple Region Representation Network (MRRNet) that aims to discover the discriminative information from different human regions. Firstly, a Stable Region Representation (SRR) layer is proposed to capture important clues from the stable regions and exchange temporal information by cross-relation aware operation. Secondly, a Multiple Region Representation (MRR) layer is designed to address the unstable regions and preserve the attention on stable regions. Thirdly, SRR and MRR can be conveniently inserted into multiple stages of the deep residual networks and significantly improve the performance of the network. Comprehensive experiments validate the effectiveness of our network. Particularly, MRRNet achieves 86.7% mAP and 91.1% Rank-1 accuracy on the MARS dataset, which outperforms state-of-the-arts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nanocrystalline Cu–20Zr (wt.%) films were obtained from the cast master alloy by magnetron sputtering. Potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning electron ...microscopy were employed to characterize the corrosion behavior of the sputtered nanocrystalline Cu–20Zr films and the corresponding cast Cu–20Zr alloy in HCl aqueous solutions with various concentrations (0.1, 0.5 and 1.0 mol L
−
1). Results showed that the corrosion resistance of the sputtered nanocrystalline Cu–20Zr films is superior to that of the cast Cu–20Zr alloy. The improvement of the corrosion resistance through nanocrystallization is explained by (i) the formation of a continuous Cu-rich layer at the corrosion potential, and (ii) the formation of a copper–chloride complex layer in the potential range for simultaneous dissolution of Cu and Zr.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Propose a control framework for two-region bi-modal traffic networks with 3D-MFD.•Integrate perimeter control with regional bus service frequency setting.•Formulate dynamics of regional bus systems ...with regional bus frequencies.•Develop a modified GA for optimizing control inputs.
Public buses and private vehicles are two main transportation modes for urban road traffic. It has strong flow interactions between the two traffic modes. From data analysis, the vehicle density of a traffic mode not only determine its flow, but also affect the flow of the other mode. With such mixed vehicle flows, the application of traditional traffic management that controls each vehicle flow system separately is limited. Thus, it is beneficial to control both bus and private vehicle flows in an integrated way. Under such bi-modal traffic management, the network efficiency cannot be reflected by vehicle flows since the occupancies of the traffic modes are greatly different. It leads to that the control objective should be necessarily based on passengers. To do so, we adopt bi-modal passenger-based macroscopic fundamental diagram (3D-pMFD) to capture the relations among vehicle accumulations and the total passenger flow in a network. From this aggregate perspective, a passenger-oriented traffic control strategy is proposed by integrating the perimeter control and the regional bus service frequency setting. The characteristics of both traffic modes, especially the operation strategy of buses, are taken into account in the model to describe the bi-modal traffic flow dynamics. A control framework comprised of optimization and simulation is established using model predictive control. The corresponding passenger-based optimization problem is solved by a modified genetic algorithm. With multiple data collected from the network of Shenzhen City in China, numerical experiments are designed to verify the validity and efficiency of the proposed integrated control strategy. Results show that: (1) the proposed strategy can maintain a high level of passenger flow during peak hour with a relatively high demand; (2) the interest of private vehicles is guaranteed even if buses are more recommended in the control strategy; (3) the crowding degree in a bus is reduced properly, which is able to improve the attraction of buses during peak hours; and (4) the proposed passenger-oriented objective results in a comprehensively good performance of the bi-modal network system.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
BACKGROUND: Many studies have showed that apoptosis of endothelial cells plays a curial role in the progress of sepsis. But the role of simvastatin in apoptosis of endothelial cells induced by sepsis ...is not clear. The present study aimed to investigate the role of simvastatin in apoptosis of endothelial cells induced by sepsis and its mechanism.METHODS: Human umbilical vein endothelial cells(HUVECs) were randomly divided into three groups: control group, sepsis serum intervention group(sepsis group) and simvastatin+sepsis serum intervention group(simvastatin group). After 24-hour incubation with corresponding culture medium, the relative growth rate of HUVECS in different groups was detected by MTT assay; the apoptosis of HUVECs was detected by Hoechst33258 assay and fl ow cytometry; and the expression of the Bcl-2 and Bax genes of HUVECs was detected by PCR.RESULTS: Compared with the sepsis group, HUVECs in the simvastatin group had a higher relative growth rate. Apoptotic HUVECs decreased significantly in the simvastatin group in comparison with the sepsis group. Expression of the Bcl-2 gene in HUVECs decreased obviously, but the expression of the Bax gene increased obviously after 24-hour incubation with sepsis serum; however, the expression of the Bcl-2 and Bax genes was just the opposite in the simvastatin group.CONCLUSIONS: Our study suggests that simvastatin can inhibit apoptosis of endothelial cells induced by sepsis through upregulating the expression of Bcl-2 and downregulating Bax. It may be one of the mechanisms for simvastatin to treat sepsis.
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FFLJ, NUK, ODKLJ, UL, UM, UPUK
Upper gastrointestinal bleeding (UGIB) is a lethal complication of biliary-pancreatic surgery (BPS). The role of endoscopic intervention has not been fully defined in such a critical condition. The ...aim of this study was to assess the efficacy and safety of endoscopic hemostasis in a retrospective cohort.
Consecutive patients with acute UGIB after BPS who received interventional endoscopy between January 2007 and August 2020 were included in this study. The clinical characteristics were collected and analyzed to screen for predictive factors significantly associated with successful hemostasis.
Among 37,772 patients who underwent BPS, 26 patients (0.069%) developed acute UGIB. The sites and causes of hemorrhage were as follows: gastroenteric anastomoe (n=17), gastric stump (n=2), jejunal anastomose (n=1), duodenal bulb ulcer (n=2), pancreatojejunal anastomosis hemorrhage (n=1), cholangiojejunal anastomose (n=1), gastroenteric anastomose and gastric stump hemorrhage (n=1), and Dieulafoy lesion (n=1). Successful endoscopic hemostasis was achieved in 19 (73.1%) of the 26 UGIB patients. In the 7 patients who failed endotherapy, 1 patient received a successful radiologic intervention, 6 patients underwent reoperation and achieved hemostasis in 4, and the other 2 patients died after reoperation. Logistic regression analysis showed that presentation-to-endoscopy time (≤12 h) was the only independent predictive factor associated with successful endoscopic hemostasis.
Endoscopic hemostasis is relatively safe and effective in controlling UIGB after BPS. Prompt intervention (≤12 h) could improve the success rate of endoscopic hemostasis.
The Active Particle-induced X-ray Spectrometer (APXS) is an important payload mounted on the Yutu rover, which is part of the Chang'e-3 mission. The scientific objective of APXS is to perform in-situ ...analysis of the chemical composition of lunar soil and rock samples. The radioactive sources, sup 55Fe and sup 109Cd, decay and produce -particles and X-rays. The elements and their concentrations can be determined by analyzing their peak energies and intensities. APXS has analyzed both the calibration target and lunar soil once during the first lunar day and again during the second lunar day. In this study, we analyze the data from the calibration target and lunar soil on the first lunar day. Comparing the peak areas and ratios of calibration basalt and lunar soil the landing site was found to be depleted in K, and have lower Mg and Al but higher Ca, Ti, and Fe. In the future, we will obtain the elemental concentrations of lunar soil at the Chang'e-3 landing site using APXS data.
Two kinds of solid solution systems of Ta‐doped MgTiO3 were identified by X‐ray diffraction, which can be represented by the formulae MgTi1−x(Mg1/3Ta2/3)xO3 (0≤x<0.5) and MgTi1−xTaxO3 (0≤x<0.05). The ...conductivity and microwave dielectric loss for the two solid solution systems were examined by AC impedance and microwave resonator measurements, respectively. In the system MgTi1−x(Mg1/3Ta2/3)xO3, the mechanism for the solid solution formation is the isovalent substitution of
for Ti4+. In the system MgTi1−xTaxO3, the doping mechanism is the aliovalent substitution of Ta5+ for Ti4+, where for a small amount Ta doping, the oxygen vacancies formed during the high‐temperature preparation are filled by an extra oxygen introduced from Ta2O5 and further Ta doping leads to an increase in the contents of
and electrons, which was consistent with conductivity measurements. In both systems, the Q×f values improved, e.g., ∼17% for the isovalent substitution at x=0.08 and ∼10% for the aliovalent substitution at x=0.02. The filling oxygen vacancy and the substitution of Ta/Mg for Ti may contribute to the improvement of Q×f values for both systems.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
•K.S Bfr can store Cd2+ in protein cavities in vitro.•The engineering bacteria with K.S Bfr can enhance the removal of Cd2+ from water.•Bacterioferritin up-regulates the ribosomal metabolic pathway.
...Cadmium can enter water through various industrial pollutants, posing serious threats to the ecological environment and human health. This study unveiled an effective method for removing Cd2+ from water by introducing bacterioferritin, known as Candidatus Kuenenia stuttgartiensis (K.S Bfr), into engineering bacteria (EB) to facilitate metal ion removal via K.S Bfr storage. Additionally, the paper explores the mechanism behind Cd2+ removal by EB using K.S Bfr. The binding kinetics revealed that EB’s Cd2+ binding capacity was significantly higher than that of wild bacteria, and Cd2+ was found to enter the protein cavity of K.S Bfr in vitro. When exposed to Cd2+ concentrations ranging from 0 to 2.5 mM, EB demonstrated a survival rate above 70 %, whereas wild bacteria's survival rate remained below 50 %. The superior Cd2+ removal capacity of EB can be attributed to the intracellular storage capacity of K.S Bfr. Tandem Mass Tags quantitative proteomics analysis showed that EB mitigated cytotoxicity mainly by up-regulating the expression of binding, homeostasis, efflux, and ribosome-related proteins. K.S Bfr was identified as a major pathway for bacteria to remove Cd2+ since it provided independent storage space for Cd2+ and ensured intracellular metal ion homeostasis. This study presents an effective strategy for treating metal wastewater, offering promising new applications for bioremediation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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