Research Progress on the Relevance between Intestinal Flora and Colorectal Cancer

Cancer is a common chronic disease all over the world, which will cause serious health burden. At present, the debate about the role of intestinal flora in the prevention and control of cancer has always existed. Therefore, researchers should pay close attention to the impact of intestinal flora on several cancers (such as colon cancer, liver cancer and breast cancer). In addition, it is reported that intestinal flora may also affect the efficacy of cancer chemotherapy and immunotherapy. This paper introduces some energy research results to help clear the relationship between intestinal flora and cancer, even cancer micro environment. It can help clarify the mist of cancer and gut microbiota, let those little creatures to serve the progress of improving mankind living condition and of health and medicine

On-State Voltage Drop Analytical Model for 4H-SiC Trench IGBTs

In this paper, a model for the forward voltage drop in a 4H-SiC trench IGBT is developed. The analytical model is based on the 4H-SiC trench MOSFET voltage model and the hole-carrier concentration profile in the N-drift region for a conventional 4H-SiC trench IGBT. Moreover, an on-state voltage drop analytical model is validated using a 2D numerical simulation, and the simulation results demonstrate that there is good agreement between the ATLAS simulation data and analytic solutions

Study on syngas methanation over municipal solid waste char supported Ni catalyst

Municipal solid waste pyrolysis char (MSWC) has none suitable high-valued applications. In this research, a Ni/ MSWC catalyst was prepared by loading Ni on to MSWC through impregnation for syngas methanation. Both continuous and intermittent operations were carried out to investigate activity and stability of the Ni/MSWC catalyst. Results showed that the catalyst exhibited high activity with CO conversion reaching 100%, CH4 yield higher than 100% in the beginning. SEM images of the fresh Ni/MSWC demonstrated that Ni particles were highly dispersed on the MSWC surface. In the continuous operation, the CH4 yield maintained above 90% for 29 h. In the 60 h's intermittent operation with 10 h as a cycle, CH4 yield decreased rapidly from 102.4% in the first cycle to 78.0% at the start of the second cycle, and it decreased to around 37% at the end of the third cycle but maintained this minimum till the end; while sharp rises appeared at the start of each cycle. Decreases in CO conversion and CH4 selectivity are found to be closely related to aggregation of Ni particles, carbon deposition and collapse of the char structure. However, carbon deposition in the intermittent operation could be alleviated by N2 purging, while whisker carbon deposition was observed in the used Ni/MSWC after 39 h's continuous operation. Highly dispersed Ni particles on the MSWC surface and proper interaction between Ni and MSWC were favorable to the activity of the catalyst, but its stability should be further improved

MoOy-Pt(CuNi)x heterojunction nanostructured catalyst for promoting the oxygen reduction reaction activity property

The catalyst intrinsic area-specific activity for the oxygen reduction reaction (ORR) was constrained by the scaling relations governing the adsorption of reaction intermediates. In this study, we strategically modified the electronic band structures of Pt(CuNi)x alloy nanoparticles by varying their composition, resulting in a specific activity trend resembling a volcano shape. The introduction of MoOy shattered the existing scaling relations, leading to a significant enhancement in ORR activity of Pt alloys, surpassing the activity of Pt(CuNi)x catalysts. These findings proved the effectiveness of MoOy deposition on Pt(CuNi)x in disrupting the scaling relations, ultimately improving ORR activity

Direct synthesis of methane-rich gas from reed biomass pyrolysis volatiles over its biochar-supported Ni catalysts

Thermochemical conversion of biomass into methane is a promising way for bioenergy recovery and alleviate natural gas shortage; however, the available technologies are queried by the complex procedures. This paper proposed a new approach for the direct synthesis of methane-rich gases from reed pyrolysis volatile at atmospheric pressure, according to which the reed pyrolysis volatiles are catalyzed over reed biochar-supported Ni catalysts in two stages to be converted. Seawater and freshwater reeds were compared for preparing effective catalysts, and the influences of inorganic salts in reed biomass on the catalytic performance were explored. The reed biochar-supported Ni catalysts were also compared with gamma-Al2O3-supported Ni catalyst (Ni/gamma-Al2O3) to evaluate their activities. It has been found that freshwater reed biochar-supported Ni catalysts (Ni/FWBs) performed better than seawater reed biochar-supported catalysts (Ni/SWBs) and Ni/gamma-Al2O3 owing to their large specific surface areas, uniform Ni particle dispersions, and appropriate Ni/biochar interactions. The Ni/FWB with biochar support produced at 600 degrees C (Ni/600FWB) was the best, and its corresponded tar-free gas product was characterized by a methane yield of 188.38 L/kg( reed) after two-stage catalytic conversion. The SWBs with higher alkali metal contents corresponded to larger Ni loading amounts than that of FWBs under the same conditions; however, they suffered from Ni particle aggregation and fusion, which deteriorated their catalytic activities. The findings indicated that the inexpensive Ni/FWBs were effective for the direct synthesis of methane from biomass pyrolysis volatiles, and the approach developed in this study provides an alternative to produce methane from biomass economically

An Electric Fence-Based Intelligent Scheduling Method for Rebalancing Dockless Bike Sharing Systems

With a new generation of bike sharing services emerging, the development of dockless bike sharing services results in considerable socioeconomic and environmental benefits but also creates new issues, such as inappropriate parking behaviors and bike imbalances. To solve the inappropriate parking problem, electric fences have been introduced to guide users to park bikes in designated zones. Considering the role of electric fences in restricting user parking behaviors, an electric fence-based intelligent scheduling method for rebalancing dockless bike sharing systems is proposed in this paper. As a dynamic method that considers the real-time usage of bike sharing systems, an electric fence adjusts its capacity based on real-time information, which guides users to return bikes to electric fences with greater urgency. Because existing approaches require prespecified models and are unable to consider all the intricacies in the dynamic optimization problem, a model-free intelligent scheduling approach based on deep Q-learning that can adapt to the changing distributions of customer arrivals, available bikes, bike locations, and user travel times is used to solve the problem. Finally, a case study involving Beihang University is employed, which shows that the method performs well in rebalancing the bike sharing system and improving the mean utilization (MU) and customer satisfaction (CS)

Triggering WORM/SRAM Memory Conversion in a Porphyrinated Polyimide via Zn Complexation as the Internal Electrode

We design two novel solution processable polyimides (PIs), NH-Por-6FDA and Zn-Por-6FDA, with 5,15-bis­(4,-aminophenyl)-10,20-diphenylporphyrin (<i>trans</i>-DATPP) (electron donor) and 4,4′-(hexafluoroisoprpoylidine)­diphthalic anhydride (6FDA) (electron acceptor) as the building blocks for polymer memory applications. The chemical structures of the two polymers are mostly identical with the only difference lying in the zinc ion (Zn²⁺) insertion into the porphyrin core in the Zn-Por-6FDA. Electrical characterization indicates that the NH-Por-6FDA possesses bidirectional nonvolatile write once read many times (WORM) memory behavior, while the Zn-Por-6FDA shows vastly different volatile static random access memory (SRAM) behavior. Both polymer memory devices show high ON/OFF current ratio up to 10⁶ and exhibit excellent long-term operation stability in 10⁸ read cycles and retention time of 4000 s with no current degradation. The charge transfer (CT) and function of the donor/acceptor moiety in the polymers related with the electrical switching effect are elucidated on the basis of optical, electrochemical measurement, and quantum simulation results. The inserted zinc ion in the porphyrin is suggested to form an internal electrode and act as a bridge during the electronic transition process, which facilitates both the CT and back CT, consequently triggering the WORM/SRAM conversion upon Zn complexation. The results observed here indicate the significance of metal-complexation on the memory effects, and will attract the attention of the researchers to use noble transition metals for the suitable expecting memory devices

Tuning Electrical Memory Behavior from Nonvolatile to Volatile by Varying Tethering Positions of the Anthracene Moiety in Functional Polyimides

In this work, three functional polyimides, in which the diaminophenylaminoanthracene (DAPAA) group served as the electron donor and 4,4′-hexafluoroisopropylidene dianhydride (6FDA) served as the electron acceptor, were synthesized and denoted as 1-DAPAA-6FDA, 2-DAPAA-6FDA, and 9-DAPAA-6FDA. The only difference between the three polyimides was that the anthracene group in DAPAA was attached to the nitrogen atom through different tethering positions (1-, 2-, and 9-). Characterization results indicate that the 1-DAPAA-6FDA and 9-DAPAA-6FDA based memory devices exhibit nonvolatile write once read many times memory (WORM) behavior, while the 2-DAPAA-6FDA based memory device exhibits volatile static random access memory (SRAM) behavior. Quantum chemical calculation results indicate that a lower dihedral angle between the anthracene group and the molecular backbone of 2-DAPAA-6FDA caused better coplanar structure for charge transfer (CT) and back CT processes, which accounts for the observed volatile SRAM memory performance. All of the polyimides possess excellent long-term operational stability. This work reveals the possibility of tuning memory behavior by elaborately adjusting the spatial conformation of the electron donor, providing feasible guidance for the design of polymer memory materials