•The expression of GDNF is downregulated in DSS-induced colitis in mice.•GDNF facilitates macrophage polarization towards the M2-like phenotype.•The PI3K/AKT pathway may contribute to the regulation ...of GDNF on macrophage.•Macrophages are required for the anticolitic benefit of GDNF in mice.
Glial cell line-derived neurotrophic factor (GDNF) has been reported to protect mice from intestinal inflammation, but its anti-inflammatory mechanisms are poorly understood. Here we found that there was a downregulation in intestinal expression of GDNF accompanied by an increase of M1 macrophages in dextran sulfate sodium (DSS)-induced colitis in mice. GDNF treatment could facilitate the macrophages polarization towards the M2-like phenotype in DSS-treated mice and LPS-stimulated RAW264.7 cells, and reduce pro-inflammatory cytokines and increase anti-inflammatory cytokines. Mechanistically, the activation of PI3K/AKT pathway might contribute to the regulation of GDNF on macrophage phenotypes and inflammatory response. Moreover, the administration of GDNF significantly ameliorated colitis in DSS-treated mice, but this benefit of GDNF was diminished by macrophage depletion. Therefore, we propose a new mechanism whereby GDNF suppresses DSS-induced colitis in mice via a macrophage-mediated pathway.
An Organic Rankine Cycle (ORC) system used in the Internal Combustion Engine (ICE) exhaust heat recovery was proposed and techno-economically analyzed based on various working fluids. It is ...significant to recover ICE exhaust heat (about one third of energy generated from the fuel) by ORC system. In this paper, the suitable working fluids have been screened and recommended for the ORC system, among 20 fluids (boiling point temperature range from −51.60 to 32.05 °C) analyzed on the rated condition of one popular commercial diesel generator set. The cycle parameters, including the thermal efficiency (ηth), the expansion ratio (v2/v1), the net power output per unit mass flow rate of hot exhaust (Pnet), the ratio of total heat transfer area to net power output (A/Wnet), and electricity production cost (Epc), have also been analyzed and optimized. Results show that R141b, R123 and R245fa present the highest ηth and Pnet values ranging from 16.60% to 13.30% (ηth value), and from 60 to 49 kJ/kg (Pnet value). Meanwhile, the three fluids also express the lowest Epc values ranging from 0.30 to 0.35$/kWh, and lowest A/Wnet values ranging from 0.436 to 0.516 m2/kW. The optimum evaporating pressures for R141b, R123, R245fa are ranging from 2.8 MPa to 3.6 MPa.
Research Subject: Waste heat recovery technology in internal combustion engine; The key technology on the improvement of ICE efficiency.
▸ We proposed an organic Rankine cycle recovering Internal Combustion Engine exhaust heat. ▸ We established techno-economically model and did analysis based on 20 working fluids. ▸ System performance express better at high evaporating pressure. ▸ R141b, R123 and R245fa present the highest thermal efficiency ηth and Pnet values. ▸ R141b, R123 and R245fa express the lowest electricity production cost Epc and A/Wnet values.
Background
The current coronavirus disease 2019 pandemic highlights the potential of eHealth. Drawing the knowledge map of eHealth research through data mining and visual analysis technology was ...helpful to systematically present the research status and future trends of global academic circles.
Methods
Based on the web of Science Core Collection (SCIE/SSCI) database, using bibliometric theory and visual analysis technology, this work analyzed the global eHealth research publications from 2000 to 2021, and introduced the interdisciplinary characteristics, hot topics and future trends in this field.
Results
A total of 10188 authors, 891 journals, 3586 institutions, 98 countries using 12 languages had conducted eHealth research in the world. The United States, the Netherlands, Australia and the United Kingdom were the main forces and international cooperation. However, the international co-operation between Eastern and Western countries was still relatively few. The frontier of global eHealth research mainly focused on #0eHealth innovation, #1physical activity, #2generalised anxiety disorder, #3lightweight authentication protocol, #4 eHealth information, #5technology readiness, #6 ehealth literacy scale, #7family carer, #8citance analysis, #9 guiding patient. Clusters #3 lightweight authentication protocol and #9 guiding patient were the latest clusters, indicating the research trend and direction of eHealth in the future.
Conclusions
Cooperation network framework at the regional, national and global levels and the cooperation of multidisciplinary teams with complementary backgrounds and expertise were needed to realize the in-depth popularization and application of eHealth knowledge. Interdisciplinary international cooperation should be the trend of eHealth research in the future.
Since the birth of cyanidation, it has been dominant in the gold extraction industry. Recently, with the increasing awareness of environmental hazards and potential risks posed by the severe toxicity ...of cyanide, attempts to seek alternative lixiviants have arisen. Over the past three decades, a significant amount of literature has examined alternative lixiviants to cyanide for recovering gold, while few industrial applications have been reported due to various obstacles, such as toxicity, excessive consumption, or low leaching efficiency. These obstacles are progressively overcome in multiple ways, including process improvement, system optimization, use of co-intensifying systems, and development of additives. In this paper, related studies about alternative lixiviants and methods such as cyanide, thiosulfate, thiourea, thiocyanate, polysulfides, halides, and microbial leaching are summarized. The history, fundamentals, advancements, and challenges of alternative lixiviants are fully concluded to provide a reference for cleaner gold production. In addition, the comprehensive performance of lixiviants was evaluated according to a novel evaluation criterion proposed in terms of economy, efficiency, and environment.
Display omitted
•The history and mechanisms of gold lixiviants in gold extraction were reviewed.•A novel evaluation criterion was proposed to evaluate the performance of lixiviants.•The current advances and progress of each lixiviant were summarized.•The challenges and prospects of each lixiviant were forecasted.
Lithium-air battery has attracted extensively attention and now developing catalysts with high electrocatalytic activity is one of the challenges for lithium-air battery. In this paper, 3D ...hierarchical porous spinel CoFe2O4 hollow nanospheres were first prepared by a facile hydrothermal method. The hollow CoFe2O4 nanospheres have unique bimodal porous structure which consists of micropores and mesopores. The catalytic activity of the CoFe2O4 hollow nanospheres for oxygen reduction reaction (ORR) has been studied and compared with the acetylene black, the solid CoFe2O4 nanospheres and the commercial Pt/C by using rotating ring-disk electrode (RRDE) technique. The spinel CoFe2O4 hollow nanospheres exhibit superior catalytic activity for the ORR compared to the acetylene black and the solid CoFe2O4 nanospheres. Besides, the spinel CoFe2O4 hollow nanospheres also afford high catalytic activity for the oxygen evolution reaction (OER). Furthermore, the hollow CoFe2O4 nanospheres show the smallest overpotential between ORR and OER. The chronoamperometric studies show that the CoFe2O4 hollow nanospheres exhibit excellent stability for both the ORR and OER. The high ORR and OER activities and stabilities of CoFe2O4 hollow nanospheres could be attributed to their special 3D hierarchical porous structure. This material shows a significant potential application on lithium-air battery.
Abstract
Early optical observations of gamma-ray bursts can significantly contribute to the study of the central engine and physical processes therein. However, of the thousands observed so far, only ...a few have data at optical wavelengths in the first minutes after the onset of the prompt emission. Here we report on GRB 190106A, whose afterglow was observed in optical bands just 36 s after the Swift/BAT trigger, i.e., during the prompt emission phase. The early optical afterglow exhibits a bimodal structure followed by a normal decay, with a faster decay after ∼
T
0
+ 1 day. We present optical photometric and spectroscopic observations of GRB 190106A. We derive the redshift via metal absorption lines from Xinglong 2.16 m/BFOSC spectroscopic observations. From the BFOSC spectrum, we measure
z
= 1.861 ± 0.002. The double-peak optical light curve is a significant feature predicted by the reverse-forward external-shock model. The shallow decay followed by a normal decay in both the X-ray and optical light curves is well explained with the standard forward-shock model with late-time energy injection. Therefore, GRB 190106A offers a case study for GRB emission from both reverse and forward shocks.
The mechanisms of the oxygen reduction reaction (ORR) on Au surfaces are revisited in electrolytes with different pH values by using a combination of electrochemical and in situ surface‐enhanced ...Raman scattering spectroscopy. Surprisingly, the in situ Raman signal of the O−O stretching vibration was detected during the ORR on a Au surface by using a λ=785 nm laser. Both the intermediate products O2− and H2O2 could be detected, which indicates the difficulty of the further reduction H2O2 and results in a lower electron transfer number, especially in neutral and acid electrolytes. The weak absorption ability of HO2 on the Au surface may explain the poor ORR in neutral and acid electrolytes. This work not only provides a deep insight to understand the reduction mechanisms of O2 on Au in electrolytes with different pH values but also supplies a new idea for the selection and optimization of electrolytes and efficient electrocatalysts for oxygen reduction.
Golden oldie: The mechanism of the oxygen reduction reaction (ORR) is not clear as it is a multielectron reaction and the pH value is a crucial factor. Detailed reaction pathways of the ORR on a gold surface in electrolytes with different pH values are investigated by using electrochemical techniques and in situ surface‐enhanced Raman spectroscopy. A decrease in the generation rate of the intermediate HO2 could be an effective strategy to increase the ORR in electrolytes with a low pH value.
Different types of waste heat recovery technologies available onboard ships have been discussed from the perspective of technical principle and application feasibility. Study of basic principle, ...novel methods, existing designs, theoretical and experimental analyses, economics and feasibility are discussed in this paper. The primary focus of this paper is to provide a better understanding of the options available for waste heat recovery and using in various applications onboard ocean-going ships to improve fuel economy and environmental compliance.
A constrained predictive speed controller with an input current limit and a constrained predictive current controller (CPCC) with an input voltage limit are proposed for high-performance sensorless ...interior permanent magnet synchronous motor (IPMSM) drive systems. Recent predictive controllers for sensorless IPMSM drives tend to focus on unconstrained predictive controllers, which do not consider the voltage or current limitations of inverters and may cause responses that are not smooth. The proposed constrained predictive controllers in this article solve these problems by imposing constraints in the performance index for real-time optimization. Simplified numerical solutions that use Hildreth quadratic programming are used to identify active constraints, and then the control inputs are limited within their physical ranges. In addition, a simple external load estimator based on the Lyapunov function is designed to compensate for external load disturbances. Moreover, a current-slope-based rotor position estimation method, which does not require any extra hardware or high-frequency signal generators or occupy any dc-link voltage, is implemented to accurately estimate the rotor position and speed. The proposed method in this article improves the dynamic performance and reduces computational complexity when implemented in sensorless IPMSM drive systems. The proposed methods have quick transient responses, excellent load disturbance responses, good tracking capabilities, and good robustness. The sensorless IPMSM drive system proposed in this article is operated at full-range speeds, from 1 to 3000 r/min. Several simulations and experimental results validate the effectiveness of the proposed constrained predictive controllers.
The surface permanent magnet synchronous motor (SPMSM) drive system has been widely used in the industry due to its high power density, high efficiency and easy to control. nature The author proposes ...a speed‐loop frequency‐adaptive periodic controller and a current‐loop optimal harmonic periodic controller for a fault‐tolerant SPMSM drive system, including normal operating conditions and faulty operating conditions. The faulty conditions consist of an insulated gate bipolar transistor (IGBT) open‐circuit and an IGBT short‐circuit. A digital signal processor, TMS‐320F‐2808, manufactured by Texas Instruments, is used as a control centre to execute the proposed fault‐detection, fault‐diagnosis, frequency‐adaptive and optimal harmonic periodic control algorithms. Experimental results show the proposed advanced periodic controllers can provide better performance than the proportional integral controller and the classic periodic controller, including transient responses, load disturbance responses, and tracking responses under normal and faulty conditions.
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